Banu Kaşkatepe | Ankara University (original) (raw)

Papers by Banu Kaşkatepe

Ankara Universitesi Eczacilik Fakultesi Dergisi

In this study we aimed to determine the development of resistance against subinhibitory concentra... more In this study we aimed to determine the development of resistance against subinhibitory concentrations of ciprofloxacin and levofloxacin of the Escherichia coli strains. Fifty E.coli strains that are susceptible to ciprofloxacin and levofloxacin have been included in this study. Minimal Inhibitory Concentration (MIC)s were detected by macro dilution method. In order to investigate the resistance development, the E.coli strains were left to incubate at 37°C for one night in subinhibitory concentrations (1/2 x MIC), then incubated in antibiotic free Mueller-Hinton broth for one night. In this way, after eight sequential passages, second MICs were detected. The third MICs were determined by repeating the same process based on the newly determined MIC values. Accordingly, as of the first MICs, after 16 successive passages an increase of MIC values against subinhibitory concentrations of ciprofloxacin was observed in all E.coli strains. This was the same for levofloxacin except for three strains; however, there were striking increases such as 64 or 128 times in the remaining strains. The use of antimicrobials for long treatment durations, taking care to monitor dose regulations and proper usage is recommended.

To determine the susceptibilities of fluconazole and voriconazole based on slime production by Ca... more To determine the susceptibilities of fluconazole and voriconazole based on slime production by Candida spp. Methods: Candida strains (115) isolated in the period between January 2011 and January 2012 were included in this study. Conventional methods were used for the identification. Candida albicans and non-C. albicans isolates were tested for slime production with modified tube adherence test and antifungal resistance with disk diffusion method. Results: Slime positivity was 31.3 % in all Candida species. Slime positivity in non-C.albicans isolates (44.89 %) was higher than in C. albicans species (21.21 %). All C. albicans isolates were sensitive to fluconazole and voriconazole. The highest resistance to fluconazole (40 %) and voriconazole (5%) was by C. glabrata strains. Conclusion: Species definition and determination of antifungal susceptibility patterns are advised for the proper management and treatment of patients.

The aim of this study was to increase rhamnolipid production by formulating media using kefir and... more The aim of this study was to increase rhamnolipid production by formulating media using kefir and fish meal for Pseudomonas aeruginosa strains isolated from different environmental resources. The strains, named as H1, SY1, and ST1, capable of rhamnolipid production were isolated from soil contaminated with wastes originating from olive and fish oil factories. Additionally, P. aeruginosa ATCC 9027 strain, which is known as rhamnolipid producer, was included in the study. Initially, rhamnolipid production by the strains was determined in Mineral Salt Medium (MSM) and then in media prepared by using kefir and fish meal. The obtained rhamnolipids were purified and quantified according to . The quantity of rhamnolipids of ATCC, H1 and SY1 strains in kefir media were determined as 11.7 g/L, 10.

Urinary tract infections (UTI) are among the most commonly encountered infections and are thus as... more Urinary tract infections (UTI) are among the most commonly encountered infections and are thus associated with widespread usage of antibiotics. Escherichia coli is the commonest bacteria isolated in UTI and treatment alternatives are limited in extended spectrum beta-lactamase (ESBL) producers.

There has been an increased interest in essential oils in recent years in accordance with new tre... more There has been an increased interest in essential oils in recent years in accordance with new treatments against pathogens. The aim of the present study was to investigate the contents and to compare the antimicrobial activity of different brands of commercial oils with two natural cinnamon oils. Antibacterial and antifungal activities of cinnamon oils were estimated using disc diffusion and macro dilution methods against Enterococcus faecalis ATCC 19433, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Escherichia coli ATCC 35218, Staphylococcus aureus ATCC 29213, Staphylococcus aureus ATCC 25923, methicillin resistant Staphylococcus aureus ATCC 43300, Pseudomonas aeruginosa ATCC 9027, Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis ATCC 6633, Klebsiella pneumonia RSKK 574, Candida albicans ATCC 10231, Candida albicans ATCC 033.

Widespread existence of drug-resistant pathogens poses a threat to the successful treatment of ba... more Widespread existence of drug-resistant pathogens poses a threat to the successful treatment of bacterial diseases and increases the need for new antibacterial agents. Natural products are the basic source of antibacterial therapeutic agents for now, and will remain so in the future. Therefore, the aim of this study was to determine the antibacterial activity of cinnamon oil against carbapenem-resistant nosocomial isolates of Acinetobacter baumannii (111) and Pseudomonas aeruginosa (136). The essential oil composition of cinnamon oil was analyzed by GC, GC/MS and the antimicrobial effect of cinnamon oil was determined by disk diffusion method. The observed zone diameters were compared with carbapenem breakpoints (CLSI standard) and it was found that only one of the P. aeruginosa isolates was within resistance limits. Thus, cinnamon oil has antimicrobial activity with potential use as an antimicrobial agent in the pharmaceutical industry and an additive in the food industry.

Giriş: Son yıllarda ülkemizde ve dünyada üropatojen Escherichia coli izolatlarında üriner sistem ... more Giriş: Son yıllarda ülkemizde ve dünyada üropatojen Escherichia coli izolatlarında üriner sistem infeksiyonu tedavisinde sık kullanılan antibiyotiklere karşı duyarlılık azalmaktadır. Bu çalışmada, üriner sistem infeksiyonu etkeni olan E. coli izolatlarının fosfomisin duyarlılığının araştırılması amaçlanmıştır. Materyal ve Metod: Çalışmaya 2280 idrar örneği arasında üreme saptanan 567 (%24.9) izolat dahil edilmiştir. Şubat 2012-Şubat 2013 tarihleri arasında laboratuvarımızdan izole edilen 389 (%68.6) E. coli izolatının fosfomisin duyarlılığı retrospektif olarak değerlendirilmiştir. İzolatların duyarlılığı "Clinical and Laboratory Standards Institute (CLSI)" kriterlerine göre disk difüzyon yöntemiyle yapılmıştır. Bulgular: Toplam 389 (%68.6) üropatojen E. coli izolatı çalışılmıştır. E. coli izolatlarında fosfomisin duyarlılığı %99.5 olarak tespit edilmiştir. Sadece iki suş fosfomisine dirençli olarak bulunmuştur. Sonuç: Üriner sistem infeksiyonlarında fosfomisin, yüksek düzey duyarlılık oranları nedeniyle üriner sistem infeksiyonlarında tercih edilebilir bir antimikrobiyal ajandır. Introduction: In our country and the world, susceptibility of uropathogenic Escherichia coli strains to commonly used antibiotics in the treatment of urinary tract infections has decreased in recent years. In this study, it was aimed to determine the susceptibility of urinary tract infection isolate E. coli to fosfomycin. Materials and Methods: Five hundred and sixty-seven (24.9%) strains out of 2280 urine samples were included in the study. The susceptibility results of 389 (%68.6) E. coli strains collected from our laboratory between February 2012 and February 2013 to fosfomycin was examined retrospectively. Susceptibility of the isolates was determined by the disk diffusion method according to Clinical and Laboratory Standards Institute criteria. Results: Totally three hundred and eighty-nine (%68.6) uropathogenic E. coli strains were used in the study. Antibiotic susceptibility of E. coli isolates was detected as 99.5% to fosfomycin. Only two isolates were found resistant to fosfomycin. Conclusion: Due to high susceptibility rates of fosfomycin at urinary tract infections, it can be preferred in urinary tract infections as an antimicrobial agent.

Clindamycin has been an alternative to methicillin as a result of incrase the prevelance of methi... more Clindamycin has been an alternative to methicillin as a result of incrase the prevelance of methicillin resistant staphylococci strains. However, inducible Macrolide-Lincosamide-Streptogramin B (iMLS B ) resistance to clindamycin could limit the use of this drug. The aim of this study was to determine the prevalance of iMLSB resistance in staphylococci strains, isolated from various clinical samples. 79 (21%) methicillin resistant Staphylococcus aureus (MRSA) and 60 (16%) methicillin sensitive S. aureus (MSSA), 154 (41.1%) methicillin resistant and 82 (21.9%) methicillin sensitive coagulase negative stapylococci for a total of 375 isolates were included in this study. iMLS B resistance was investigated by D-test using clindamycin and erytromycin disk on the basis of guidelines by the Clinical and Laboratory Standards Institute. 223 of total 375 staphylococci isolates were found to be resistant to erythromycin (ER-R). 55 (24.6%) of total 223 (59.5%) ER-R isolates showed iMLS B phenotype. 40 of 55 iMLS B resistant isolates were also methicillin resistant. Since iMLS B resistance is not detected by classical susceptibility tests, using of D-test on a routine laboratory application will help safety usage of clindamycin in treatment of especially methicillin resistant staphylococci infections.

Purpose: To determine the efficacies of three commercially available new generation disinfectants... more Purpose: To determine the efficacies of three commercially available new generation disinfectants against some bacteria and yeast. Methods: Three commercially available new generation disinfectant (0.2 % chlorine dioxide, 0.3 % chlorine dioxide and 50 % hydrogen peroxide-stabilized by colloidal silver) were screened for their antimicrobial activity against Escherichia coli ATCC 25922, Klebsiella pneumonia RSKK 574, Pseudomonas aeruginosa ATCC 9027, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. aureus ATCC 43300 (methicillin resistant), S. epidermidis ATCC 12228 (non-biofilm forming), S. epidermidis ATCC 35948 (biofilm forming) and Candida albicans ATCC 10231. Quantitative suspension test was used to determine the efficacies of the disinfectants at contact times of 1, 3 and 5 min. Results: All of the new generation disinfectants were effective against test microorganisms at all test contact times. Conclusions: The findings indicate that the tested new generation disinfectants may be useful for routine disinfection purposes.

Surfactants are chemical products widely used in our daily life in toothpaste and other personal ... more Surfactants are chemical products widely used in our daily life in toothpaste and other personal hygiene and cosmetic products, and in several industries. Biosurfactants are surfactants of biological origin that can be produced by microorganisms and have many advantages, such as low toxicity and high biodegradability, compared to synthetic counterparts. Unfortunately, high production costs limit the use of biosurfactants. Low-cost production is the most important factor for biosurfactants to be able to compete in the global market place. This review presents general information on rhamnolipid biosurfactant produced by Pseudomonas species, as well as on their production and applications. In addition, industrial products and their wastes used for rhamnolipid production are reviewed in detail based on recent studies.

Objective: Antibiotic resistance has turned into a global public health problem in all over the w... more Objective: Antibiotic resistance has turned into a global public health problem in all over the world. Intestinal flora bacteria perform many important functions for human health. As a member of microbiota Escherichia coli cause many infections. This study was aimed to determine antibiotic susceptibility of microbiota member E. coli isolates against to the antibiotics that used in treatment.

Ankara Universitesi Eczacilik Fakultesi Dergisi

In this study we aimed to determine the development of resistance against subinhibitory concentra... more In this study we aimed to determine the development of resistance against subinhibitory concentrations of ciprofloxacin and levofloxacin of the Escherichia coli strains. Fifty E.coli strains that are susceptible to ciprofloxacin and levofloxacin have been included in this study. Minimal Inhibitory Concentration (MIC)s were detected by macro dilution method. In order to investigate the resistance development, the E.coli strains were left to incubate at 37°C for one night in subinhibitory concentrations (1/2 x MIC), then incubated in antibiotic free Mueller-Hinton broth for one night. In this way, after eight sequential passages, second MICs were detected. The third MICs were determined by repeating the same process based on the newly determined MIC values. Accordingly, as of the first MICs, after 16 successive passages an increase of MIC values against subinhibitory concentrations of ciprofloxacin was observed in all E.coli strains. This was the same for levofloxacin except for three strains; however, there were striking increases such as 64 or 128 times in the remaining strains. The use of antimicrobials for long treatment durations, taking care to monitor dose regulations and proper usage is recommended.

To determine the susceptibilities of fluconazole and voriconazole based on slime production by Ca... more To determine the susceptibilities of fluconazole and voriconazole based on slime production by Candida spp. Methods: Candida strains (115) isolated in the period between January 2011 and January 2012 were included in this study. Conventional methods were used for the identification. Candida albicans and non-C. albicans isolates were tested for slime production with modified tube adherence test and antifungal resistance with disk diffusion method. Results: Slime positivity was 31.3 % in all Candida species. Slime positivity in non-C.albicans isolates (44.89 %) was higher than in C. albicans species (21.21 %). All C. albicans isolates were sensitive to fluconazole and voriconazole. The highest resistance to fluconazole (40 %) and voriconazole (5%) was by C. glabrata strains. Conclusion: Species definition and determination of antifungal susceptibility patterns are advised for the proper management and treatment of patients.

The aim of this study was to increase rhamnolipid production by formulating media using kefir and... more The aim of this study was to increase rhamnolipid production by formulating media using kefir and fish meal for Pseudomonas aeruginosa strains isolated from different environmental resources. The strains, named as H1, SY1, and ST1, capable of rhamnolipid production were isolated from soil contaminated with wastes originating from olive and fish oil factories. Additionally, P. aeruginosa ATCC 9027 strain, which is known as rhamnolipid producer, was included in the study. Initially, rhamnolipid production by the strains was determined in Mineral Salt Medium (MSM) and then in media prepared by using kefir and fish meal. The obtained rhamnolipids were purified and quantified according to . The quantity of rhamnolipids of ATCC, H1 and SY1 strains in kefir media were determined as 11.7 g/L, 10.

Urinary tract infections (UTI) are among the most commonly encountered infections and are thus as... more Urinary tract infections (UTI) are among the most commonly encountered infections and are thus associated with widespread usage of antibiotics. Escherichia coli is the commonest bacteria isolated in UTI and treatment alternatives are limited in extended spectrum beta-lactamase (ESBL) producers.

There has been an increased interest in essential oils in recent years in accordance with new tre... more There has been an increased interest in essential oils in recent years in accordance with new treatments against pathogens. The aim of the present study was to investigate the contents and to compare the antimicrobial activity of different brands of commercial oils with two natural cinnamon oils. Antibacterial and antifungal activities of cinnamon oils were estimated using disc diffusion and macro dilution methods against Enterococcus faecalis ATCC 19433, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Escherichia coli ATCC 35218, Staphylococcus aureus ATCC 29213, Staphylococcus aureus ATCC 25923, methicillin resistant Staphylococcus aureus ATCC 43300, Pseudomonas aeruginosa ATCC 9027, Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis ATCC 6633, Klebsiella pneumonia RSKK 574, Candida albicans ATCC 10231, Candida albicans ATCC 033.

Widespread existence of drug-resistant pathogens poses a threat to the successful treatment of ba... more Widespread existence of drug-resistant pathogens poses a threat to the successful treatment of bacterial diseases and increases the need for new antibacterial agents. Natural products are the basic source of antibacterial therapeutic agents for now, and will remain so in the future. Therefore, the aim of this study was to determine the antibacterial activity of cinnamon oil against carbapenem-resistant nosocomial isolates of Acinetobacter baumannii (111) and Pseudomonas aeruginosa (136). The essential oil composition of cinnamon oil was analyzed by GC, GC/MS and the antimicrobial effect of cinnamon oil was determined by disk diffusion method. The observed zone diameters were compared with carbapenem breakpoints (CLSI standard) and it was found that only one of the P. aeruginosa isolates was within resistance limits. Thus, cinnamon oil has antimicrobial activity with potential use as an antimicrobial agent in the pharmaceutical industry and an additive in the food industry.

Giriş: Son yıllarda ülkemizde ve dünyada üropatojen Escherichia coli izolatlarında üriner sistem ... more Giriş: Son yıllarda ülkemizde ve dünyada üropatojen Escherichia coli izolatlarında üriner sistem infeksiyonu tedavisinde sık kullanılan antibiyotiklere karşı duyarlılık azalmaktadır. Bu çalışmada, üriner sistem infeksiyonu etkeni olan E. coli izolatlarının fosfomisin duyarlılığının araştırılması amaçlanmıştır. Materyal ve Metod: Çalışmaya 2280 idrar örneği arasında üreme saptanan 567 (%24.9) izolat dahil edilmiştir. Şubat 2012-Şubat 2013 tarihleri arasında laboratuvarımızdan izole edilen 389 (%68.6) E. coli izolatının fosfomisin duyarlılığı retrospektif olarak değerlendirilmiştir. İzolatların duyarlılığı "Clinical and Laboratory Standards Institute (CLSI)" kriterlerine göre disk difüzyon yöntemiyle yapılmıştır. Bulgular: Toplam 389 (%68.6) üropatojen E. coli izolatı çalışılmıştır. E. coli izolatlarında fosfomisin duyarlılığı %99.5 olarak tespit edilmiştir. Sadece iki suş fosfomisine dirençli olarak bulunmuştur. Sonuç: Üriner sistem infeksiyonlarında fosfomisin, yüksek düzey duyarlılık oranları nedeniyle üriner sistem infeksiyonlarında tercih edilebilir bir antimikrobiyal ajandır. Introduction: In our country and the world, susceptibility of uropathogenic Escherichia coli strains to commonly used antibiotics in the treatment of urinary tract infections has decreased in recent years. In this study, it was aimed to determine the susceptibility of urinary tract infection isolate E. coli to fosfomycin. Materials and Methods: Five hundred and sixty-seven (24.9%) strains out of 2280 urine samples were included in the study. The susceptibility results of 389 (%68.6) E. coli strains collected from our laboratory between February 2012 and February 2013 to fosfomycin was examined retrospectively. Susceptibility of the isolates was determined by the disk diffusion method according to Clinical and Laboratory Standards Institute criteria. Results: Totally three hundred and eighty-nine (%68.6) uropathogenic E. coli strains were used in the study. Antibiotic susceptibility of E. coli isolates was detected as 99.5% to fosfomycin. Only two isolates were found resistant to fosfomycin. Conclusion: Due to high susceptibility rates of fosfomycin at urinary tract infections, it can be preferred in urinary tract infections as an antimicrobial agent.

Clindamycin has been an alternative to methicillin as a result of incrase the prevelance of methi... more Clindamycin has been an alternative to methicillin as a result of incrase the prevelance of methicillin resistant staphylococci strains. However, inducible Macrolide-Lincosamide-Streptogramin B (iMLS B ) resistance to clindamycin could limit the use of this drug. The aim of this study was to determine the prevalance of iMLSB resistance in staphylococci strains, isolated from various clinical samples. 79 (21%) methicillin resistant Staphylococcus aureus (MRSA) and 60 (16%) methicillin sensitive S. aureus (MSSA), 154 (41.1%) methicillin resistant and 82 (21.9%) methicillin sensitive coagulase negative stapylococci for a total of 375 isolates were included in this study. iMLS B resistance was investigated by D-test using clindamycin and erytromycin disk on the basis of guidelines by the Clinical and Laboratory Standards Institute. 223 of total 375 staphylococci isolates were found to be resistant to erythromycin (ER-R). 55 (24.6%) of total 223 (59.5%) ER-R isolates showed iMLS B phenotype. 40 of 55 iMLS B resistant isolates were also methicillin resistant. Since iMLS B resistance is not detected by classical susceptibility tests, using of D-test on a routine laboratory application will help safety usage of clindamycin in treatment of especially methicillin resistant staphylococci infections.

Purpose: To determine the efficacies of three commercially available new generation disinfectants... more Purpose: To determine the efficacies of three commercially available new generation disinfectants against some bacteria and yeast. Methods: Three commercially available new generation disinfectant (0.2 % chlorine dioxide, 0.3 % chlorine dioxide and 50 % hydrogen peroxide-stabilized by colloidal silver) were screened for their antimicrobial activity against Escherichia coli ATCC 25922, Klebsiella pneumonia RSKK 574, Pseudomonas aeruginosa ATCC 9027, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, S. aureus ATCC 43300 (methicillin resistant), S. epidermidis ATCC 12228 (non-biofilm forming), S. epidermidis ATCC 35948 (biofilm forming) and Candida albicans ATCC 10231. Quantitative suspension test was used to determine the efficacies of the disinfectants at contact times of 1, 3 and 5 min. Results: All of the new generation disinfectants were effective against test microorganisms at all test contact times. Conclusions: The findings indicate that the tested new generation disinfectants may be useful for routine disinfection purposes.

Surfactants are chemical products widely used in our daily life in toothpaste and other personal ... more Surfactants are chemical products widely used in our daily life in toothpaste and other personal hygiene and cosmetic products, and in several industries. Biosurfactants are surfactants of biological origin that can be produced by microorganisms and have many advantages, such as low toxicity and high biodegradability, compared to synthetic counterparts. Unfortunately, high production costs limit the use of biosurfactants. Low-cost production is the most important factor for biosurfactants to be able to compete in the global market place. This review presents general information on rhamnolipid biosurfactant produced by Pseudomonas species, as well as on their production and applications. In addition, industrial products and their wastes used for rhamnolipid production are reviewed in detail based on recent studies.

Objective: Antibiotic resistance has turned into a global public health problem in all over the w... more Objective: Antibiotic resistance has turned into a global public health problem in all over the world. Intestinal flora bacteria perform many important functions for human health. As a member of microbiota Escherichia coli cause many infections. This study was aimed to determine antibiotic susceptibility of microbiota member E. coli isolates against to the antibiotics that used in treatment.