Search results for: gram-positive and gram negative bacteria

Authors: Sajjad Jafari, Reza Akbari

Abstract:

Background and Aim: Chrysin, a flavonoid compound found in medicinal plants, honey, and propolis, has potential biological activities that make it an important perspective in the treatment of infectious and cancer diseases. The aim of this review study is to evaluate the biological activities of chrysin in the treatment of infectious and cancer diseases. Material and Methods: The present study is a review study that searched reputable scientific databases such as PubMed, Google Scholar, Scopus, and Web of Science from 2000 to 2023 using keywords such as antimicrobial, antifungal, chrysin, anticancer, antioxidants, and infectious diseases. The researchers examined 25 articles to determine the biological activities of chrysin. Results: Chrysin has high inhibitory or lethal activities on gram-positive and gram-negative bacteria, including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Enterococcus faeces. It also has anti-biofilm effects and antifungal effects on strains such as Aspergillus niger and Candida albicans. Chrysin also has anticancer effects on various cancers, including colorectal cancer, pancreatic cancer, breast cancer, and MCF-7 cancer, which have been confirmed in vitro and in vivo. Conclusion: Chrysin has the potential as an important therapeutic option in the treatment of infectious and cancer diseases. Its high antimicrobial and anticancer activities, combined with its low toxicity in nanoparticle form, make it a promising candidate for further clinical trials. The production of anti-microbial and anti-cancer drugs from natural substances, such as chrysin, is a valuable contribution to the field of medicine.

Keywords: chrysin, antimicrobial, anticancer, infectious diseases

Procedia PDF Downloads 80

Authors: R. Gounina-Allouane, N. Ouali, F. Z. Berrabah, A. Bentaleb

Abstract:

For a long time, the Gram-positive spore-forming bacteria Bacillus thuringiensis (Bt) has been widely used in biological control against devastating and disease vectors insects. This is due to the insecticidal activity of its crystalline parasporal inclusion (crystals) predominantly comprised of one or more proteins (Cry and Cyt proteins) also called δ-endotoxins, produced during sporulation. The shape and composition of Bt crystals vary among strains and crystalline proteins are extremely varied (more than 475 cry gene were discovered). The insecticidal activity of Bt crystals is very well studied, thus their insecticidal mode of action is well established, however, their antimicrobial effect is largely unknown. The lack of data on the antimicrobial effect of crystalline proteins of Bt and the need for searching new antimicrobial molecules encouraged us to carried out this study. The antibacterial effect of δ-endotoxines produced by two Bt stains; a strain isolated from soil at northern of Algeria (Bt 7.2.B), and a strain isolated from a bioinsecticide (Bacillus thuringiensis var aizawai), activated by proteolysis, was assayed on clinical bacterial strains and ATCC collection ones respectively. Gram positive and negative clinical bacterial strains (Escherichia coli, Klebsiella pneumonaie, Pseudomonas aeruginosa, Staphylococcus aureus) were sensitive to activated Bt 72B endotoxins. Similarly, bacterial strains from ATCC collection (Escherichia coli ATCC 25922, Pseudomonas aerugenosa ATCC 27853, Staphylococcus aureus ATCC 25923) were sensitive to activated B. thuringiensis var aizawai δ-endotoxines. The activated δ-endotoxins were separated by SDS-PAGE.

Keywords: Bacillus thuringiensis, crystals, cry proteins, δ-endotoxins, antibacterial activity

Procedia PDF Downloads 423

Authors: Essam A. Makky, Chan Cai Wen, Muna Jalal, Mashitah M. Yusoff

Abstract:

Termites are considered as important pests that could cause severe wood damage and economic losses in urban, agriculture and forest of Malaysia. The ability of termites to degrade cellulose depends on association of gut cellulolytic microflora or better known as mutual symbionts. With the idea of disrupting the mutual symbiotic association, better pest control practices can be attained. This study is aimed to isolate cellulolytic bacteria from the gut of termites and carry out antibacterial studies for the termite. Confirmation of cellulase activity is done by qualitative and quantitative methods. Impacts of antibiotics and their combinations, as well as heavy metals and disinfectants, are conducted by using disc diffusion method. Effective antibacterial agents are then subjected for termite treatment to study the effectiveness of the agents as termiticides. 24 cellulolytic bacteria are isolated, purified and screened from the gut of termites. All isolates were identified as Gram-negative with either rod or cocci in shape. For antibacterial studies result, isolates were found to be 100% sensitive to 4 antibiotics (rifampicin, tetracycline, gentamycin, and neomycin), 2 heavy metals (cadmium and mercury) and 3 disinfectants (lactic acid, formalin, and hydrogen peroxide). 22 out of 36 antibiotic combinations showed synergistic effect while 15 antibiotic combinations showed an antagonistic effect on isolates. The 2 heavy metals and 3 disinfectants that showed 100% effectiveness, as well as 22 antibiotic combinations, that showed synergistic effect were used for termite control. Among the 27 selected antibacterial agents, 12 of them were found to be effective to kill all the termites within 1 to 6 days. Mercury, lactic acid, formalin and hydrogen peroxide were found to be the most effective termiticides in which all termites were killed within 1 day only. These effective antibacterial agents possess a great potential to be a new application to control the termite pest species in the future.

Keywords: antibacterial, cellulase, termicide, termites

Procedia PDF Downloads 447

Authors: Jamie Lynn Co, Mary Shiela Ariola-Ramos

Abstract:

Myroides are aerobic, yellow-pigmented, non-motile, non-fermenting gram-negative rods. They are commonly found in the environment such as water and soil. Although found in the environment, Myroides are rare pathogens of humans. Myroides spp. primarily infect immunocompromised patients, often with diabetes mellitus, liver cirrhosis, chronic kidney disease, chronic obstructive pulmonary disease or prolonged corticosteroid therapy. We present a case of a 70-year-old immunocompromised patient with diabetes mellitus, chronic renal failure, diagnosed with sepsis caused by Myroides spp. The primary portal and source of infection were the pustules and boils found on the lower extremities of the patient. Susceptibility testing showed that our isolate was only susceptible to ciprofloxacin and meropenem; and following the treatment, the patient recovered. Myroides continues to be a rare pathogen of humans that is prevalent in our environment. It primarily affects immunocompromised patients such as those with uncontrolled diabetes mellitus, chronic kidney disease, etc. Despite their low virulence, physicians should consider this opportunistic pathogen as possible etiologic agent especially in cases wherein there is lack of response to commonly used antibiotics.

Keywords: bacteremia, immunocompromised, gram negative rods, Myroides

Procedia PDF Downloads 134

Authors: R. Gounina-Allouane, N. Ouali, F. Z. Berrabah, A. Bentaleb

Abstract:

For a long time, the Gram-positive spore-forming bacteria Bacillus thuringiensis (Bt) has been widely used in biological control against devastating and disease vectors insects. This is due to the insecticidal activity of its crystalline parasporal inclusion (crystals) predominantly comprised of one or more proteins (Cry and Cyt proteins) also called δ-endotoxins, produced during sporulation. The shape and composition of Bt crystals vary among strains and crystalline proteins are extremely varied (more than 475 cry gene were discovered). The insecticidal activity of Bt crystals is very well studied, thus their insecticidal mode of action is well established, however, their antimicrobial effect is largely unknown. The lack of data on the antimicrobial effect of crystalline proteins of Bt and the need for searching new antimicrobial molecules encouraged us to carried out this study. The antibacterial effect of δ-endotoxines produced by two Bt stains; a strain isolated from soil at northern of Algeria (Bt 7.2.B), and a strain isolated from a bioinsecticide (Bacillus thuringiensis var aizawai), activated by proteolysis, was assayed on clinical bacterial strains and ATCC collection ones respectively. Gram positive and negative clinical bacterial strains (Escherichia coli, Klebsiella pneumonaie, Pseudomonas aeruginosa, Staphylococcus aureus) were sensitive to activated Bt 72B endotoxins. Similarly, bacterial strains from ATCC collection (Escherichia coli ATCC 25922, Pseudomonas aerugenosa ATCC 27853, Staphylococcus aureus ATCC 25923) were sensitive to activated B. thuringiensis var aizawai δ-endotoxines. The activated δ-endotoxins were separated by SDS-PAGE.

Keywords: Bacillus thuringiensis, crystals, cry proteins, δ-endotoxins, antibacterial activity

Procedia PDF Downloads 409

Authors: K. Petrosyan, R. Piwowarczyk, K. Ruraż, S. Thijs, J. Vangronsveld, W. Kaca

Abstract:

Holoparasitic plants are flowering heterotrophic angiosperms which with the help of an absorbing organ - haustorium, attach to another plant, the so-called the host. Due to the different hosts, unusual lifestyle, lack of roots, chlorophylls and photosynthesis, these plants are interesting and unique study objects for global biodiversity. The seeds germination of the parasitic plants also is unique: they germinate only in response to germination stimulants, namely strigolactones produced by the root of an appropriate host. Resistance of the seeds on different environmental conditions allow them to stay viable in the soil for more than 20 years. Among the wide range of plant protection mechanisms the endophytic communities have a specific role. In this way, they have the potential to mitigate the impacts of adverse conditions such as soil salinization. The major objective of our study was to compare the bacterial endo-microbiomes from seeds of two holoparasitic plants from Orobanchaceae family, Cistanche – C. armena (Armenia) and C. phelypaea (Portugal) – from saline habitats different in soil water status. The research aimed to perform how environmental conditions influence on the diversity of the bacterial communities of C. armena and C. phelypaea seeds. This was achieved by comparison of the endophytic microbiomes of two species and isolation of culturable bacteria. A combination of culture-dependent and molecular techniques was employed for the identification of the seed endomicrobiome (culturable and unculturable). Using the V3-V4 hypervariable region of the 16S rRNA gene, four main taxa were identified: Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, but the relative proportion of the taxa was different in each type of seed. Generally, sixteen phyla, 323 genera and 710 bacterial species were identified, mainly Gram negative, halotolerant bacteria with an environmental origin. However, also some unclassified and unexplored taxonomic groups were found in the seeds of both plants. 16S rRNA gene sequencing analysis from both species identified the gram positive, endospore forming, halotolerant and alkaliphile Bacillus spp. which suggests that the endophytic bacteria of examined seeds possess traits that are correlated with the natural habitat of their hosts. The cultivable seed endophytes from C. armena and C. phelypaea were rather similar, notwithstanding the big distances between their growth habitats - Armenia and Portugal. Although the seed endophytic microbiomes of C. armena and C. phelypaea contain a high number of common bacterial taxa, also remarkable differences exist. We demonstrated that the environmental conditions or abiotic stresses influence on diversity of the bacterial communities of holoparasiotic seeds. To the best of our knowledge the research is the first report of endophytes from seeds of holoparasitic Cistanche armena and C. phelypaea plants.

Keywords: microbiome, parasitic plant, salinity, seeds

Procedia PDF Downloads 48

Authors: Ramutė Miseikienė, Saulius Tusas

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Somatic cell count and bacteria count are the main indicators of cow milk quality. The aim of this study was to analyze and compare parameters of milk quality in different-sized cows herds. Milk quality of ten dairy cows farms during one year period was analyzed. Dairy farms were divided into five groups according to number of cows in the farm (under 50 cows, 51–100 cows, 101–200 cows, 201–400 cows and more than 400 cows). The averages of somatic cells bacteria count in milk and milk freezing temperature were analyzed. Also, these parameters of milk quality were compared during outdoor (from May to September) and indoor (from October to April) periods. The largest number of SCC was established in the smallest farms, i.e., in farms under 50 cows and 51-100 cows (respectively 264±9,19 and 300±10,24 thousand/ml). Reliable link between the smallest and largest dairy farms and farms with 101-200 and 201-400 cows and count of somatic cells in milk has not been established (P > 0.05). Bacteria count had a low tendency to decrease when the number of cows in farms increased. The highest bacteria number was determined in the farms with 51-100 cows and the the lowest bacteria count was in milk when 201-400 and more than 401 cows were kept. With increasing the number of cows milk maximal freezing temperature decreases (significant negative trend), i. e, indicator is improving. It should be noted that in all farms milk freezing point never exceeded requirements (-0.515 °C). The highest difference between SCC in milk during the indoor and outdoor periods was established in farms with 201-400 cows (respectively 218.49 thousand/ml and 268.84 thousand/ml). However, the count of SC was significantly higher (P < 0.05) during outdoor period in large farms (201-400 and more cows). There was no significant difference between bacteria count in milk during both – outdoor and indoor – periods (P > 0.05).

Keywords: bacteria, cow, farm size, somatic cell count

Procedia PDF Downloads 240

Authors: B. S. Chandrashekar, M. K. Prasannakumar, P. Buela Parivallal, Sahana N. Banakar, Swathi S. Patil, H. B. Mahesh, D. Pramesh

Abstract:

Bacterial soft rot is one of the most often seen diseases in many plant species globally, resulting in considerable yield loss. Radish roots with dark water-soaked lesions, maceration of tissue, and a foul odour were collected in the Kolar region, India. Two isolates were obtained from rotted samples that demonstrated morphologically unpigmented, white mucoid convex colonies on nutrient agar medium. The isolated bacteria (RDH1 and RDH3) were gram-negative, rod-shaped bacteria with biochemically distinct characteristics similar to the type culture of Enterobacter cloacae ATCC13047 and Bergy's handbook of determinative bacteriology. The 16s rRNA gene was used to identify Enterobacter species. On carrot, potato, tomato, chilli, bell pepper, knolkhol, cauliflower, cabbage, and cucumber slices, the Koch′s postulates were fulfilled, and the pathogen was also pathogenic on radish, cauliflower, and cabbage seedlings were grown in a glasshouse. After 36 hours, both isolates exhibited a hypersensitive sensitivity to Nicotianatabacum. Semi-quantitative analysis revealed that cell wall degrading enzymes (CWDEs) such as pectin lyase, polygalacturonase, and cellulase (p=1.4e09) contributed to pathogenicity, whereas isolates produced biofilms (p=4.3e-11) that help in host adhesion. This is the first report in India of radish soft rot caused by E. cloacae.

Keywords: soft rot, enterobacter cloacae, 16S rRNA, nicotiana tabacum, and pathogenicity

Procedia PDF Downloads 95

Authors: Denis V. Axenov-Gribanov, Irina V. Voytsekhovskaya, Evgenii S. Protasov, Maxim A. Timofeyev

Abstract:

Isolated ecosystems existing under specific environmental conditions have been shown to be promising sources of new strains of actinobacteria. The taiga forest of Baikal Siberia has not been well studied, and its actinobacterial population remains uncharacterized. The proximity between the huge water mass of Lake Baikal and high mountain ranges influences the structure and diversity of the plant world in Siberia. Here, we report the isolation of eighteen actinobacterial strains from male cones of Pinus sylvestris trees growing on the shore of the ancient Lake Baikal in Siberia. The actinobacterial strains were isolated on solid nutrient MS media and Czapek agar supplemented with cycloheximide and phosphomycin. Identification of actinobacteria was carried out by 16S rRNA gene sequencing and further analysis of the evolutionary history. Four different liquid and solid media (NL19, DNPM, SG and ISP) were tested for metabolite production. The metabolite extracts produced by the isolated strains were tested for antibacterial and antifungal activities. Also, antiradical activity of crude extracts was carried out. Strain Streptomyces sp. IB 2014 I 74-3 that active against Gram-negative bacteria was selected for dereplication analysis with using the high-yield liquid chromatography with mass-spectrometry. Mass detection was performed in both positive and negative modes, with the detection range set to 160–2500 m/z. Data were collected and analyzed using Bruker Compass Data Analysis software, version 4.1. Dereplication was performed using the Dictionary of Natural Products (DNP) database version 6.1 with the following search parameters: accurate molecular mass, absorption spectra and source of compound isolation. Thus, in addition to more common representative strains of Streptomyces, several species belonging to the genera Rhodococcus, Amycolatopsis, and Micromonospora were isolated. Several of the selected strains were deposited in the Russian Collection of Agricultural Microorganisms (RCAM), St. Petersburg, Russia. All isolated strains exhibited antibacterial and antifungal activities. We identified several strains that inhibited the growth of the pathogen Candida albicans but did not hinder the growth of Saccharomyces cerevisiae. Several isolates were active against Gram-positive and Gram-negative bacteria. Moreover, extracts of several strains demonstrated high antioxidant activity. The high proportion of biologically active strains producing antibacterial and specific antifungal compounds may reflect their role in protecting pollen against phytopathogens. Dereplication of the secondary metabolites of the strain Streptomyces sp. IB 2014 I 74-3 was resulted in the fact that a total of 59 major compounds were detected in the culture liquid extract of strain cultivated in ISP medium. Eight compounds were preliminarily identified based on characteristics described in the Dictionary of Natural Products database, using the search parameters Streptomyces sp. IB 2014 I 74-3 was found to produce saframycin A, Y3 and S; 2-amino-3-oxo-3H-phenoxazine-1,8-dicarboxylic acid; galtamycinone; platencin A4-13R and A4-4S; ganefromycin d1; the antibiotic SS 8201B; and streptothricin D, 40-decarbamoyl, 60-carbamoyl. Moreover, forty-nine of the 59 compounds detected in the extract examined in the present study did not result in any positive hits when searching within the DNP database and could not be identified based on available mass-spec data. Thus, these compounds might represent new findings.

Keywords: actinobacteria, Baikal Lake, biodiversity, male cones, Pinus sylvestris

Procedia PDF Downloads 201

Authors: Anoff Anim, Lila Mahmoud, Maria Katsikogianni, Sanjit Nayak

Abstract:

Sustained and controlled delivery of antimicrobial drugs have been largely studied recently using metal organic frameworks (MOFs)and different polymers. However, much attention has not been given to combining both MOFs and biodegradable polymers, which would be a good strategy in providing a sustained gradual release of the drugs. Herein, we report a comparative study of the sustained and controlled release of widely used antibacterial drugs, cephalexin and metronidazole, from zinc-based MOF-5 incorporated in biodegradable polycaprolactone (PCL) and poly-lactic glycolic acid (PLGA) membranes. Cephalexin and metronidazole were separately incorporated in MOF-5 post-synthetically, followed by their integration into biodegradable PLGA and PCL membranes. The pristine MOF-5 and the loaded MOFs were thoroughly characterized by FT-IR, SEM, TGA and PXRD. Drug release studies were carried out to assess the release rate of the drugs in PBS and distilled water for up to 48 hours using UV-Vis Spectroscopy. Four bacterial strains from both the Gram-positive and Gram-negative types, Staphylococus aureus, Staphylococuss epidermidis, Escherichia coli, Acinetobacter baumanii, were tested against the pristine MOF, pure drugs, loaded MOFs and the drug-loaded MOF-polymer composites. Metronidazole-loaded MOF-5 composite of PLGA (PLGA-Met@MOF-5) was found to show highest efficiency to inhibit the growth of S. epidermidis compared to the other bacteria strains while maintaining a sustained minimum inhibitory concentration (MIC). This study demonstrates that the combination of biodegradable MOF-polymer composites can provide an efficient platform for sustained and controlled release of antimicrobial drugs and can be a potential strategy to integrate them in biomedical devices.

Keywords: antimicrobial resistance, biodegradable polymers, cephalexin, drug release metronidazole, MOF-5, PCL, PLGA

Procedia PDF Downloads 103

Authors: Anoff Anim, Lila A. M. Mahmoud, Maria Katsikogianni, Sanjit Nayak

Abstract:

Sustained and controlled delivery of antimicrobial drugs have been largely studied recently using metal organic frameworks (MOFs)and different polymers. However, much attention has not been given to combining both MOFs and biodegradable polymers, which would be a good strategy in providing a sustained gradual release of the drugs. Herein, we report a comparative study of the sustained and controlled release of widely used antibacterial drugs, cephalexin and metronidazole, from zinc-based MOF-5 incorporated in biodegradable polycaprolactone (PCL) and poly-lactic glycolic acid (PLGA) membranes. Cephalexin and metronidazole were separately incorporated in MOF-5 post-synthetically, followed by their integration into biodegradable PLGA and PCL membranes. The pristine MOF-5 and the loaded MOFs were thoroughly characterized by FT-IR, SEM, TGA and PXRD. Drug release studies were carried out to assess the release rate of the drugs in PBS and distilled water for up to 48 hours using UV-Vis Spectroscopy. Four bacterial strains from both the Gram-positive and Gram-negative types, Staphylococus aureus, Staphylococuss epidermidis, Escherichia coli, Acinetobacter baumanii, were tested against the pristine MOF, pure drugs, loaded MOFs and the drug-loaded MOF-polymer composites. Metronidazole-loaded MOF-5 composite of PLGA (PLGA-Met@MOF-5) was found to show highest efficiency to inhibit the growth of S. epidermidis compared to the other bacteria strains while maintaining a sustained minimum inhibitory concentration (MIC). This study demonstrates that the combination of biodegradable MOF-polymer composites can provide an efficient platform for sustained and controlled release of antimicrobial drugs and can be a potential strategy to integrate them in biomedical devices.

Keywords: antimicrobial resistance, biodegradable polymers, cephalexin, drug release metronidazole, MOF-5, PCL, PLGA

Procedia PDF Downloads 98

Authors: Ali M. Elgerbi, Obied A. Alwan, Al-Taher O. Alzwei, Abdurrahim A. Elouzi

Abstract:

The binding of AFM1 to bacteria in phosphate buffer solution depended on many factors such as: availability of energy, incubation period, species and strain of bacteria. Increase in concentration of sugar showed higher removal of AFM1 and faster than in phosphate buffer alone. With 1.0% glucose lactic acid bacteria and bifidobacteria showed toxin removal ranging from 7.7 to 39.7% whereas with 10.0% glucose the percentage removal was 21.8 to 45.4% at 96 hours of incubation.

Keywords: aflatoxin M1, lactic acid bacteria, bifidobacteria , binding, phosphate buffer

Procedia PDF Downloads 475

Authors: Sajjad Jafari

Abstract:

Background and Aim: The use of herbal medicines has a long history. Today, due to the resistance of microorganisms to antibiotics and antimicrobial substances, herbal medicines have attracted attention due to their significant antimicrobial effects and low toxicity. This study aims to systematically review the antimicrobial effects of different plant extracts (Quercus infectoria) as possible candidates for treating infectious diseases. Material and Methods: The present study is a review study by searching reputable scientific databases such as PubMed, Google Scholar, Scopus, and Web of Science from 2000 to 2023 using the keywords Antimicrobial, Quercus infectoria, Medicinal herbal, Infectious diseases the latest information obtained. Results: In this study, 45 articles were found and reviewed. Quercus infectoria is a small tree native to Greece, Asia Minor, and Iran. Quercus is a plant genus in the family of Fagaceae. This species is generally known under the name ‘‘baloot” in Iran and is commonly used as a medicinal plant. The extracts used included water, hydro-alcoholic, ethanol, methanol. This plant had high inhibition activity and a lethal effect on gram-positive and gram-negative bacteria of ATCC strains, hospital, and resistant strains. Therefore, in addition to antibacterial effects, antiparasitic and antifungal effects. The seed of the plant was the most used and the most effective antimicrobial extract among the ethanol and methanol extracts. Conclusion: The findings of this study suggest that Quercus infectoria has significant antimicrobial effects against a wide range of microorganisms. This makes it a potential candidate for the development of new antimicrobial drugs. Further research is needed to confirm the efficacy and safety of Quercus infectoria in clinical trials.

Keywords: antimicrobial, Quercus infectoria, medicinal herbal, infectious diseases

Procedia PDF Downloads 55

Authors: Robin Anderson, Elizabeth Latham, David Nisbet

Abstract:

Propagation and dissemination of antimicrobial resistant and pathogenic microbes from spoiled silages and composts represents a serious public health threat to humans and animals. In the present study, the antimicrobial activity of the short chain nitro-compound, 2-nitro-1-propanol (9 mM) as well as the medium chain fatty acid, lauric acid, and its glycerol monoester, monolaurin, (each at 25 and 17 µmol/mL, respectfully) were investigated against select pathogenic and multi-drug resistant antimicrobial resistant Gram-positive bacteria common to spoiled silages and composts. In an initial study, we found that growth rates of a multi-resistant Enterococcus faecalis (expressing resistance against erythromycin, quinupristin/dalfopristin and tetracycline) and Staphylococcus aureus strain 12600 (expressing resistance against erythromycin, linezolid, penicillin, quinupristin/dalfopristin and vancomycin) were more than 78% slower (P < 0.05) by 2-nitro-1-propanol treatment during culture (n = 3/treatment) in anaerobically prepared ½ strength Brain Heart Infusion broth at 37oC when compared to untreated controls (0.332 ± 0.04 and 0.108 ± 0.03 h-1, respectively). The growth rate of 2-nitro-1-propanol-treated Listeria monocytogenes was also decreased by 96% (P < 0.05) when compared to untreated controls cultured similarly (0.171 ± 0.01 h-1). Maximum optical densities measured at 600 nm were lower (P < 0.05) in 2-nitro-1-propanol-treated cultures (0.053 ± 0.01, 0.205 ± 0.02 and 0.041 ± 0.01, respectively) than in untreated controls (0.483 ± 0.02, 0.523 ± 0.01 and 0.427 ± 0.01, respectively) for E. faecalis, S. aureus and L. monocytogenes, respectively. When tested against mixed microbial populations during anaerobic 24 h incubation of spoiled silage, significant effects of treatment with 1 mg 2-nitro-1-propanol (approximately 9.5 µmol/g) or 5 mg lauric acid/g (approximately 25 µmol/g) on populations of wildtype Enterococcus and Listeria were not observed. Mixed populations treated with 5 mg monolaurin/g (approximately 17 µmol/g) had lower (P < 0.05) viable cell counts of wildtype enterococci than untreated controls after 6 h incubation (2.87 ± 1.03 versus 5.20 ± 0.25 log10 colony forming units/g, respectively) but otherwise significant effects of monolaurin were not observed. These results reveal differential susceptibility of multi-drug resistant enterococci and staphylococci as well as L. monocytogenes to the inhibitory activity of 2-nitro-1-propanol and the medium chain fatty acid, lauric acid and its glycerol monoester, monolaurin. Ultimately, these results may lead to improved treatment technologies to preserve the microbiological safety of silages and composts.

Keywords: 2-nitro-1-propanol, lauric acid, monolaurin, gram positive bacteria

Procedia PDF Downloads 77

Authors: Anoff Anim, Lila Mahmound, Maria Katsikogianni, Sanjit Nayak

Abstract:

Sustained and controlled delivery of antimicrobial drugs have been largely studied recently using metal organic frameworks (MOFs)and different polymers. However, much attention has not been given to combining both MOFs and biodegradable polymers which would be a good strategy in providing a sustained gradual release of the drugs. Herein, we report a comparative study of the sustained and controlled release of widely used antibacterial drugs, cephalexin and metronidazole, from zinc-based MOF-5 incorporated in biodegradable polycaprolactone (PCL) and poly-lactic glycolic acid (PLGA) membranes. Cephalexin and metronidazole were separately incorporated in MOF-5 post-synthetically, followed by their integration into biodegradable PLGA and PCL membranes. The pristine MOF-5 and the loaded MOFs were thoroughly characterized by FT-IR, SEM, TGA and PXRD. Drug release studies were carried out to assess the release rate of the drugs in PBS and distilled water for up to 48 hours using UV-Vis Spectroscopy. Four bacterial strains from both the Gram-positive and Gram-negative types, Staphylococus aureus, Staphylococuss epidermidis, Escherichia coli, Acinetobacter baumanii, were tested against the pristine MOF, pure drugs, loaded MOFs and the drug-loaded MOF-polymer composites. Metronidazole-loaded MOF-5 composite of PLGA (PLGA-Met@MOF-5) was found to show highest efficiency to inhibit the growth of S. epidermidis compared to the other bacteria strains while maintaining a sustained minimum inhibitory concentration (MIC). This study demonstrates that the combination of biodegradable MOF-polymer composites can provide an efficient platform for sustained and controlled release of antimicrobial drugs, and can be a potential strategy to integrate them in biomedical devices.

Keywords: antimicrobial resistance, biodegradable polymers, cephalexin, drug release metronidazole, MOF-5, PCL, PLGA

Procedia PDF Downloads 50

Authors: Frans J. Smit, Wisdom A. Munzeiwa, Hermanus C. M. Vosloo, Lyn-Marie Birkholtz, Richard K. Haynes

Abstract:

Malaria and antimicrobial infections remain significant global health concerns, necessitating the continuous search for novel therapeutic approaches. This abstract presents an overview of the potential use of triazenes as effective agents against malaria and various antimicrobial pathogens. Triazenes are a class of compounds characterized by a linear arrangement of three nitrogen atoms, rendering them structurally distinct from their cyclic counterparts. This study investigates the efficacy of triazenes against malaria and explores their antimicrobial activity. Preliminary results revealed significant antimalarial activity of the triazenes, as evidenced by in vitro screening against P. falciparum, the causative agent of malaria. Furthermore, the compounds exhibited broad-spectrum antimicrobial activity, indicating their potential as effective antimicrobial agents. These compounds have shown inhibitory effects on various essential enzymes and processes involved in parasite survival, replication, and transmission. The mechanism of action of triazenes against malaria involves interactions with critical molecular targets, such as enzymes involved in the parasite's metabolic pathways and proteins responsible for host cell invasion. The antimicrobial activity of the triazenes against bacteria and fungi was investigated through disc diffusion screening. The antimicrobial efficacy of triazenes has been observed against both Gram-positive and Gram-negative bacteria, as well as multidrug-resistant strains, making them potential candidates for combating drug-resistant infections. Furthermore, triazenes possess favourable physicochemical properties, such as good stability, solubility, and low toxicity, which are essential for drug development. The structural versatility of triazenes allows for the modification of their chemical composition to enhance their potency, selectivity, and pharmacokinetic properties. These modifications can be tailored to target specific pathogens, increasing the potential for personalized treatment strategies. In conclusion, this study highlights the potential of triazenes as promising candidates for the development of novel antimalarial and antimicrobial therapeutics. Further investigations are necessary to determine the structure-activity relationships and optimize the pharmacological properties of these compounds. The results warrant additional research, including MIC studies, to further explore the antimicrobial activity of the triazenes. Ultimately, these findings contribute to the development of more effective strategies for combating malaria and microbial infections.

Keywords: malaria, anti-microbials, triazene, resistance

Procedia PDF Downloads 68

Authors: Nesrine Lenchi, Salima Kebbouche-Gana, Laddada Belaid, Mohamed Lamine Khelfaoui, Mohamed Lamine Gana

Abstract:

Saline lakes are extreme hypersaline environments that are considered five to ten times saltier than seawater (150 – 300 g L-1 salt concentration). Hypersaline regions differ from each other in terms of salt concentration, chemical composition and geographical location, which determine the nature of inhabitant microorganisms. In order to explore the diversity of moderate and extreme halophiles Bacteria in Chott Tinsilt (East of Algeria), an isolation program was performed. In the first time, water samples were collected from the saltern during pre-salt harvesting phase. Salinity, pH and temperature of the sampling site were determined in situ. Chemical analysis of water sample indicated that Na +and Cl- were the most abundant ions. Isolates were obtained by plating out the samples in complex and synthetic media. In this study, seven halophiles cultures of Bacteria were isolated. Isolates were studied for Gram’s reaction, cell morphology and pigmentation. Enzymatic assays (oxidase, catalase, nitrate reductase and urease), and optimization of growth conditions were done. The results indicated that the salinity optima varied from 50 to 250 g L-1, whereas the optimum of temperature range from 25°C to 35°C. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. The results showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Idiomarina, Halobacillus Thalassobacillus and Planococcus genera and what may represent a new bacterial genus.

Keywords: bacteria, Chott, halophilic, 16S rRNA

Procedia PDF Downloads 251

Authors: Sang Guen Kim, Sib Sankar Giri, Jin Woo Jun, Saekil Yun, Hyoun Joong Kim, Sang Wha Kim, Jung Woo Kang, Se Jin Han, Se Chang Park

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Emerging of the super bacteria, bacteriophages are considered to be as an alternative to antibiotics. As the demand of phage increased, economical and large production of phage is becoming one of the critical points. For the therapeutic use, what is important is to eradicate the pathogenic bacteria as fast as possible, so higher concentration of phages is generally needed for effective therapeutic function. On the contrary, for the maximum production, bacteria work as a phage producing factory. As a microbial cell factory, bacteria is needed to last longer producing the phages without eradication. Consequently, killing the bacteria fast has a negative effect on large production. In this study, Multiplicity of Infection (MOI) was manipulated based on initial bacterial inoculation and used phage pAh-6C which has therapeutic effect against Aeromonas hydrophila. 1, 5 and 10 percent of overnight bacterial culture was inoculated and each bacterial culture was co-cultured with the phage of which MOI of 0.01, 0.0001, and 0.000001 respectively. Simply changing the initial MOI as well as bacterial inoculation concentration has regulated the production quantity of the phage without any other changes to culture conditions. It is anticipated that this result can be used as a foundational data for mass production of lytic bacteriophages which can be used as the therapeutic bio-control agent.

Keywords: bacteriophage, multiplicity of infection, optimization, Aeromonas hydrophila

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Authors: Naser Shagerdi Esmaeli, Mohsen Hamidpour

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Background and Objective: Hematopoietic stem cell transplantation (HSCT) has been widely used for treating oncological and hematological diseases. Although HSCT has helped to improve patient survival, the risk of developing an infection during hospitalization is an important cause of morbidity and mortality. This study aimed to analyze the infection profile during hospitalization and the associated risk factors among patients undergoing autologous HSCT at the University Hospital, Shahid Ghazi Tabatabaei Hospital, Tabriz, Iran. Subjects and Methods: This was a cross-sectional study on patients undergoing autologous HSCT at a public university hospital. Methods: Patients with febrile neutropenia between 2015 and 2018 were retrospectively evaluated regarding their infection profile and associated risk factors. This survey included: bacterial culture and blood culture on specific media. Results: Infection occurred in 57.2% of 56 patients with febrile neutropenia. The main source of infection was the central venous catheter (25.9%). Infection was chiefly due to Gram-positive bacteria, although Gram-negative-related infections were more severe and caused a higher death rate. Sex, age, skin color, nutritional status, and underlying disease were not associated with the development of infection. Patients with severe mucositis (Grades III and IV) had a higher infection rate (P < 0.001). Patients who developed pulmonary complications during hospitalization had higher infection rates (P = 0.002). Infection was the main cause of death (57.1%) in the study sample. Conclusion: Strategies aimed at reducing infection-related mortality rates among patients undergoing autologous HSCT are necessary.

Keywords: hematopoietic stem cell, autologous bone marrow transplantation, infection profile, tabriz, Iran

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Authors: Boudjema Nouara, Mameri Nabil

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Bacteria have played an important role in water contamination as a consequence of organic pollution. In this study, an electrocoagulation process was adopted to remove fecal contamination and pathogenic bacteria from waste water. The effect of anode/cathodes materials as well as operating conditions for bacteria removal from water, such as current intensity and initial pH and temperature. The results indicated that the complete removal was achevied when using aluminium anode as anode at current intensity of 3A, initial pH of 7-8 and electrolysis time of 30 minutes. This process showed a bactericidal effect of 95 to 99% for the total and fecal coliforms and 99% to 100% for Eschercichia coli and fecal Streptococci. A decrease of 72% was recorded for sulphite-reducing Clostridia. Thus, this process has the potential to be one the options for treatment where high amount of bacteria in wastewater river.

Keywords: bacteria, el Harrach river, electrocoagulation, wastewater, treatment

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Authors: M. Knezevic, V. Marecic, M. Ozanic, I. Kelava, M. Mihelcic, M. Santic

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Francisella tularensis is a highly infectious, gram-negative intracellular bacterium and the causative agent of tularemia. The bacterium has been isolated from more than 250 wild species, including protozoa cells. Since Francisella is very virulent and persists in the environment for years, the aim of this study was to investigate whether Acanthamoeba castellanii-grown F. novicida exhibits an alteration in the resistance to disinfectants. It has been shown by other intracellular pathogens, including Legionella pneumophila that bacteria grown in amoeba exhibit more resistance to disinfectants. However, there is no data showing Francisella viability behaviour after intracellular life cycle in A. castellani. In this study, the bacterial suspensions of A. castellanii-grown or in vitro-grown Francisella were treated with three different disinfectants, and the bacterial viability after disinfection treatment was determined by a colony-forming unit (CFU) counting method, transmission electron microscopy (TEM), fluorescence microscopy as well as the leakage of intracellular fluid. Our results have shown that didecyldimethylammonium chloride (DDAC) combined with isopropyl alcohol was the most effective in bacterial killing; all in vitro-grown and A. castellanii-grown F. novicida were killed after only 10s. Surprisingly, in comparison to in vitro-grown bacteria, A. castellanii-grown F. novicida was more sensitive to decontamination by the benzalkonium chloride combined with DDAC and formic acid and the polyhexamethylene biguanide (PHMB). We can conclude that the tested disinfectants exhibit antimicrobial activity by causing a loss of structural organization and integrity of the Francisella cell wall and membrane and the subsequent leakage of the intracellular contents. Finally, the results of this study clearly demonstrate that Francisella grown in A. castellanii had become more susceptible to many disinfectants.

Keywords: Acanthamoeba, disinfectant, Francisella, sensitivity

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Authors: Okolie Pius Ifeanyi, Emerenini Emilymary Chima

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Aims: The study investigated the diversity and identities of Lactic Acid Bacteria (LAB) isolated from different fresh fruits using Molecular Nested PCR analysis and the efficacy of cell free supernatants from Lactic Acid Bacteria (LAB) isolated from fresh fruits for in vitro control of some tomato pathogens. Study Design: Nested PCR approach was used in this study employing universal 16S rRNA gene primers in the first round PCR and LAB specific Primers in the second round PCR with the view of generating specific Nested PCR products for the LAB diversity present in the samples. The inhibitory potentials of supernatant obtained from LAB isolates of fruits origin that were molecularly characterized were investigated against some tomato phytopathogens using agar-well method with the view to develop biological agents for some tomato disease causing organisms. Methodology: Gram positive, catalase negative strains of LAB were isolated from fresh fruits on Man Rogosa and Sharpe agar (Lab M) using streaking method. Isolates obtained were molecularly characterized by means of genomic DNA extraction kit (Norgen Biotek, Canada) method. Standard methods were used for Nested Polymerase Chain Reaction (PCR) amplification targeting the 16S rRNA gene using universal 16S rRNA gene and LAB specific primers, agarose gel electrophoresis, purification and sequencing of generated Nested PCR products (Macrogen Inc., USA). The partial sequences obtained were identified by blasting in the non-redundant nucleotide database of National Center for Biotechnology Information (NCBI). The antimicrobial activities of characterized LAB against some tomato phytopathogenic bacteria which include (Xanthomonas campestries, Erwinia caratovora, and Pseudomonas syringae) were obtained by using the agar well diffusion method. Results: The partial sequences obtained were deposited in the database of National Centre for Biotechnology Information (NCBI). Isolates were identified based upon the sequences as Weissella cibaria (4, 18.18%), Weissella confusa (3, 13.64%), Leuconostoc paramensenteroides (1, 4.55%), Lactobacillus plantarum (8, 36.36%), Lactobacillus paraplantarum (1, 4.55%) and Lactobacillus pentosus (1, 4.55%). The cell free supernatants of LAB from fresh fruits origin (Weissella cibaria, Weissella confusa, Leuconostoc paramensenteroides, Lactobacillus plantarum, Lactobacillus paraplantarum and Lactobacillus pentosus) can inhibits these bacteria by creating clear zones of inhibition around the wells containing cell free supernatants of the above mentioned strains of lactic acid bacteria. Conclusion: This study shows that potentially LAB can be quickly characterized by molecular methods to specie level by nested PCR analysis of the bacteria isolate genomic DNA using universal 16S rRNA primers and LAB specific primer. Tomato disease causing organisms can be most likely biologically controlled by using extracts from LAB. This finding will reduce the potential hazard from the use of chemical herbicides on plant.

Keywords: nested pcr, molecular characterization, 16s rRNA gene, lactic acid bacteria

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Authors: Kedibone Masenya, Memory Tekere, Jasper Rees

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Sorghum is an important cereal crop in the world. In particular, it has attracted breeders due to capacity to serve as food, feed, fiber and bioenergy crop. Like any other plant, sorghum hosts a variety of microbes, which can either, have a neutral, negative and positive influence on the plant. In the current study, regions (V3/V4) of 16 S rRNA were targeted to extensively assess bacterial multitrophic interactions in the phyllosphere of sorghum. The results demonstrated that the presence of a pathogen has a significant effect on the endophytic bacterial community. Understanding these interactions is key to develop new strategies for plant protection.

Keywords: bacteria, multitrophic, sorghum, target sequencing

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Authors: Nelson Rotimi Osungbemiro, Sanni Rafiu Olugbenga, Abayomi Olufemi Olajuyigbe

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Ninety Fingerlings of Clarias gariepinus were exposed to the pathogenic Flavobacterium columnare a Gram Negative bacteria responsible for high mortality in fish pond raised young fish (fries and fingerlings) of Clarias sp. in Southwestern Nigeria. After feeding with 40% crude protein pelletized fish feed for 5 days, the fishes were divided into two groups, one group was treated with extracts from Calendula officinalis flowers, while the second group was not treated (control). The results indicated that, at day 5, colony formation had been manifesting and at day 7, skin lesion occurred and at the 8th day, first mortality of fish occurred, and this continued steadily on the 9th-12th day when all the fishes were dead. Whereas, in the group that was treated with Calendula sp., no single mortality was recorded. This research shows that plant extract from Calendula flowers is an effective antimicrobial agent against the virulent pathogenic Flavobacterium columnare disease.

Keywords: antimicrobial, Flavobacterium columnare, Clarias gariepinus, fish

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Authors: Mohamed S. Selim, Nesreen A. Fatthallah, Shimaa A. Higazy, Zhifeng Hao, Ping Jing Mo

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As marine fouling-release (FR) surfaces, two new superhydrophobic nanocomposite series of polydimethylsiloxane (PDMS) loaded with reduced graphene oxide (RGO) and graphene oxide/boehmite nanorods (GO-γ-AlOOH) nanofillers were created. The self-cleaning and antifouling capabilities were modified by controlling the nanofillers' shapes and distribution in the silicone matrix. With an average diameter of 10-20 nm and a length of 200 nm, γ-AlOOH nanorods showed a single crystallinity. RGO was made using a hydrothermal process, whereas GO-γ-AlOOH nanocomposites were made using a chemical deposition method for use as fouling-release coating materials. These nanofillers were disseminated in the silicone matrix using the solution casting method to explore the synergetic effects of graphene-based materials on the surface, mechanical, and FR characteristics. Water contact angle (WCA), scanning electron, and atomic force microscopes were used to investigate the surface's hydrophobicity and antifouling capabilities (SEM and AFM). The roughness, superhydrophobicity, and surface mechanical characteristics of coatings all increased the homogeneity of the nanocomposite dispersion. To examine the antifouling effects of the coating systems, laboratory tests were conducted for 30 days using specified bacteria.PDMS/GO-γ-AlOOH nanorod composite demonstrated superior antibacterial efficacy against several bacterial strains than PDMS/RGO nanocomposite. The high surface area and stabilizing effects of the GO-γ-AlOOH hybrid nanofillers are to blame for this. The biodegradability percentage of the PDMS/GO-γ-AlOOH nanorod composite (3 wt.%) was the lowest (1.6%), while the microbial endurability percentages for gram-positive, gram-negative, and fungi were 86.42%, 97.94%, and 85.97%, respectively. The homogeneity of the GO-γ-AlOOH (3 wt.%) dispersion, which had a WCA of 151° and a rough surface, was the most profound superhydrophobic antifouling nanostructured coating.

Keywords: superhydrophobic nanocomposite, fouling release, nanofillers, surface coating

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Authors: Maryam Nejat Dehkordi, Per Lincoln, Hassan Momtaz

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Interaction of Schiff base complexes of iron and manganese (iron [N, N’ Bis (5-(triphenyl phosphonium methyl) salicylidene) -1, 2 ethanediamine) chloride, [Fe Salen]Cl, manganese [N, N’ Bis (5-(triphenyl phosphonium methyl) salicylidene) -1, 2 ethanediamine) acetate) with DNA were investigated by spectroscopic and isothermal titration calorimetry techniques (ITC). The absorbance spectra of complexes have shown hyper and hypochromism in the presence of DNA that is indication of interaction of complexes with DNA. The linear dichroism (LD) measurements confirmed the bending of DNA in the presence of complexes. Furthermore, isothermal titration calorimetry experiments approved that complexes bound to DNA on the base of both electrostatic and hydrophobic interactions. Furthermore, ITC profile exhibits the existence of two binding phases for the complex. Antibacterial activity of ligand and complexes were tested in vitro to evaluate their activity against the gram positive and negative bacteria.

Keywords: Schiff base complexes, ct-DNA, linear dichroism (LD), isothermal titration calorimetry (ITC), antibacterial activity

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Authors: Baljeet Singh Saharan

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Bioremediation is the demand of the day. Tannery and textile effluents/waste waters have lots of pollution due to presence of hexavalent Chromium. Methodologies used in the present investigations include isolation, cultivation and purification of bacterial strain. Further characterization techniques and 16S rRNA sequencing were performed. Efficient bacterial strain capable of reducing hexavalent chromium was obtained. The strain can be used for bioremediation of industrial effluents containing hexavalent Cr. A gram negative, rod shaped and yellowish pigment producing bacterial strain from tannery effluent was isolated using nutrient agar. The 16S rRNA gene sequence similarity indicated that isolate SA13A is associated with genus Luteimonas (99%). This isolate has been found to reduce 100% of hexavalent chromium Cr (VI) (100 mg L-1) 100% in 16 h. Growth conditions were optimized for Cr (VI) reduction. Maximum reduction was observed at a temperature of 37 °C and pH 8.0. Additionally, Luteimonas aestuarii SA13A showed resistance against various heavy metals like Cr+6, Cr+3, Cu+2, Zn+2, Co+2, Ni+2 and Cd+2 . Hence, Luteimonas aestuarii SA13A could be used as potent Cr (VI) reducing strain as well as significant bioremediator in heavy metal contaminated sites.

Keywords: bioremediation, chromium, eco-friendly, heavy metals

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Authors: Recep Keşli, Gülşah Aşık, Cengiz Demir, Onur Türkyılmaz

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Objective: Serratia species are identified as aerobic, motile Gram negative rods. The species Serratia marcescens (S. marcescens) causes both opportunistic and nosocomial infections. The genus Providencia is Gram-negative bacilli and includes urease-producing that is responsible for a wide range of human infections. Although most Providencia infections involve the urinary tract, they are also associated with gastroenteritis, wound infections, and bacteremia. The aim of this study was evaluate the antimicrobial resistance rates of S. marcescens and Providencia spp. strains which had been isolated from various clinical materials obtained from different patients who belongs to intensive care units (ICU) and inpatient clinics. Methods: A total of 35 S. marcescens and Providencia spp. strains isolated from various clinical samples admitted to Medical Microbiology Laboratory, ANS Research and Practice Hospital, Afyon Kocatepe University between October 2013 and September 2015 were included in the study. Identification of the bacteria was determined by conventional methods and VITEK 2 system (bio-Merieux, Marcy l’etoile, France) was used additionally. Antibacterial resistance tests were performed by using Kirby Bauer disc (Oxoid, Hampshire, England) diffusion method following the recommendations of CLSI. Results: The distribution of clinical samples were as follows: upper and lower respiratory tract samples 26, 74.2 % wound specimen 6, 17.1 % blood cultures 3, 8.5%. Of the 35 S. marcescens and Providencia spp. strains; 28, 80% were isolated from clinical samples sent from ICU. The resistance rates of S. marcescens strains against trimethoprim-sulfamethoxazole, piperacillin-tazobactam, imipenem, gentamicin, ciprofloxacin, ceftazidime, cefepime and amikacin were found to be 8.5 %, 22.8 %, 11.4 %, 2.8 %, 17.1 %, 40 %, 28.5 % and 5.7 % respectively. Resistance rates of Providencia spp. strains against trimethoprim-sulfamethoxazole, piperacillin-tazobactam, imipenem, gentamicin, ciprofloxacin, ceftazidime, cefepime and amikacin were found to be 10.2 %, 33,3 %, 18.7 %, 8.7 %, 13.2 %, 38.6 %, 26.7%, and 11.8 % respectively. Conclusion: S. marcescens is usually resistant to ampicillin, amoxicillin, amoxicillin/clavulanate, ampicillin/sulbactam, cefuroxime, cephamycins, nitrofurantoin, and colistin. The most effective antibiotic on the total of S. marcescens strains was found to be gentamicin 2.8 %, of the totally tested strains the highest resistance rate found against to ceftazidime 40 %. The lowest and highest resistance rates were found against gentamiycin and ceftazidime with the rates of 8.7 % and 38.6 % for Providencia spp.

Keywords: Serratia marcescens, Providencia spp., antibiotic resistance, intensive care unit

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Authors: Nastaran Soltani

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Heavy metals such as Mercury are toxic elements that enter the environment through different ways and endanger the environment, plants, animals, and humans’ health. Microbial activities reduce the amount of heavy metals. Therefore, an effective mechanism to eliminate heavy metals in the nature and factory slops, is using bacteria living in polluted areas. Karun River in Khuzestan Province in Iran has been always polluted by heavy metals as it is located among different industries in the region. This study was performed based on the data from sampling water and sediments of four stations across the river during the four seasons of a year. The isolation of resistant bacteria was performed through enrichment and direct cultivation in a solid medium containing mercury. Various bacteria such as Pseudomonas sp., Serratia Marcescens, and E.coli were identified as mercury-resistant bacteria. The power of these bacteria to remove mercury varied from 28% to 86%, with strongest power belonging to Pseudomonas sp. isolated in spring making a good candidate to be used for mercury biological removal from factory slops.

Keywords: bacteria, Karun River, mercury, biological removal, mercury-resistant

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Authors: Nassim Belkacem, Amina Azzam, Dalila Haouchine, Kahina Bennacer, Samira Soufit

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Objective: To evaluate the antioxidant activity of the methanolic extract along with the antimicrobial activity of the essential oil of the aerial parts of Rosmarinus officinalis L. collected in the region of Bejaia (northern center of Algeria). Materials and methods: The polyphenols and flavonoids contents of the methanolic extract were measured. The antioxidant activity was evaluated using two methods: the ABTS method and DPPH assay. The antimicrobial activity was studied by the agar diffusion method against five bacterial strains (Three Gram positive strains and two Gram negative strains) and one fungus. Results: The total polyphenol and flavonoid content was about 43.8 mg gallic acid equivalent per gram (GA Eq/g) and 7.04 mg quercetin equivalent per gram (Q Eq/g), respectively. In the ABTS assay, the rosemary extract has shown an inhibition of 98.02% at the concentration of 500ug/ml with a half maximal inhibitory concentration value (IC50) of 194.92ug/ml. The results of DPPH assay have shown that the rosemary extract has an inhibition of 94.67 % with an IC50 value of 17.87ug/ml, which is lower than that of Butylhydroxyanisol (BHA) about 6.03ug/ml and ascorbic acid about 1.24μg/ml. The yield in essential oil of rosemary obtained by hydrodistillation was 1.42%. Based on the determination of the diameter of inhibition, different antimicrobial activity of the essential oil was revealed against the six tested microbes. Escherichia coli from the University Hospital (UH), Streptococcus aureus (UH) and Pseudomonas aeruginosa ATCC have a minimum inhibitory concentration value (MIC) of 62.5µl/ml. However, Bacillus sp (UH) and Staphylococcus aureus ATCC have an MIC value of 125μl/ml. The inhibition zone against Candida sp was about 24 mm. The aromatograms showed that the essential oil of rosemary exercises an antifungal activity more important than the antibacterial one.

Keywords: Rosmarinus officinalis L., maceration, essential oil, antioxidant, antimicrobial activity

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