Detection of small colony variants among methicillin-resistant staphylococcus aureus blood isolates

Staphylococcus aureus small colony variants (SCVs) are associated with chronic and persistent infections. Methicillin-resistant S. aureus (MRSA) SCVs cause more severe infections and mortality rates are higher in comparison with infections caused by MRSA. Our objective was to document the prevalence and phenotypical characteristics of SCVs among MRSA blood isolates. MRSA strains isolated from blood during 1999-2009 were evaluated retrospectively. Among 299 MRSA isolates, suspected colonies were inoculated onto Columbia blood agar and Schaedler agar. Columbia blood agar was incubated in normal atmosphere and Schaedler agar in 5-10% CO2, both at 35°C. If the small, nonpigmented, nonhemolytic colonies on Columbia blood agar were seen as normal-sized, hemolytic, and pigmented colonies on Schaedler agar, they were considered as MRSA SCVs. Six MRSA SCVs were detected. When subcultures were made, four of them reversed to phenotypically normal S. aureus, but two isolates were stable as SCV phenotype. The prevalence of SCVs among MRSA blood isolates was found as 6/299 (2%) with 2 (0.67%) stable. The detection of SCVs among MRSA blood isolates was reported from Turkey for the first time in this study. As the clinical significance of MRSA infections is well documented, evaluation of MRSA SCVs in clinical samples, especially from intensive care patients and those who have chronic and persistent infections are important to consider. © Mary Ann Liebert, Inc. 2016

Lens Concentration of Ofloxacin and Lomefloxacin in an Experimental Endophthalmitis Model

Background: Bacterial endophthalmitis is a serious complication of ocular surgery and penetrating trauma. The primary causative organisms are strains of Staphylococcus aureus and Staphylococcus epidermidis. Fluoroquinolones are widely used to treat endophthalmitis. There are a few studies on the penetration of fluoroquinolones into the lens in inflamed eyes. A literature search did not identify any data regarding penetration of topical ofloxacin into the lens in normal and inflamed eyes. Objective: The aim of this study was to determine the penetration of topical ofloxacin and lomefloxacin into the lens in a rabbit endophthalmitis model. Methods: New Zealand white rabbits were randomly divided into 2 groups. The left eyes were infected with an intravitreal inoculation of S aureus. The right eyes were used as a noninoculated control. Groups 1 and 2 received topical ofloxacin and lomefloxacin treatment, respectively, 24 hours after the inoculation. Two drops of the study drugs were instilled in the eyes every 30 minutes for 3 hours and then every 60 minutes for 3 hours. Lens samples were obtained 30 minutes after the last ofloxacin or lomefloxacin drops were administered. High-performance liquid chromatography was used to determine the fluoroquinolone concentration. Results: Ten rabbits were equally divided into the 2 treatment groups. There was no significant difference in mean (SD) lens concentrations between the control and inoculated eyes in either treatment group-ofloxacin (0.26 [0.32] mu g/mL vs 0.11 [0.05] mu g/mL, respectively) and lomefloxacin (0.50 [0.87] mu g/mL vs 0.12 [0.08] mu g/mL, respectively). Conclusions: The results of this small experimental study found that topical ofloxacin and lomefloxacin can accumulate in the crystalline lens after installation. Inflammation did not affect the penetration of ofloxacin or lomefloxacin into the lens.WoSScopu

Detection of the frequency of PER-1 type extended-spectrum ?-lactamase–producing Acinetobacter baumannii clinical isolates in Turkey: a multicenter study

Background/aim: β-Lactamases are an important resistance mechanism in Acinetobacter baumannii. Pseudomonas extended-resistance (PER-1) type β-lactamase–producing strains have been reported from various geographic locations; however, PER-1 type β-lactamases from Turkish hospitals have not been investigated extensively. The aim of this study was to determine the prevalence of PER-1 type β-lactamases in A. baumannii isolates in various regions of Turkey. Materials and methods: A total of 763 clinical A. baumannii isolates were collected from 9 university hospitals and 2 state hospitals between 2008 and 2011. Molecular amplification of the OXA-51 gene from the A. baumannii genome was performed in order to verify identification of the species. Real-time polymerase chain reaction was used to detect blaPER-1 genes. Results: PER-1 was detected in 24.6% of the isolates. The annual frequencies of the PER-1 enzyme were detected as 52.2%, 35.9%, and 8.3% in 2008, 2009, and 2010, respectively. PER-1 prevalence decreased gradually over time. The differences observed in PER-1 prevalence among the regions of Turkey were statistically significant (chi-square test; P < 0.001). Conclusion: These data demonstrate that the frequency of detection of PER-1 type β-lactamases in A. baumannii species has decreased in Turkey. However, the increased carbapenem resistance, together with multidrug resistance, has created a worrisome situation regarding this pathogen

Detection Of The Frequency Of Per-1 Type Extended-Spectrum Β-Lactamase Producing Acinetobacter Baumannii Clinical İsolates İn Turkey: A Multicenter Study

Background/aim: β-Lactamases are an important resistance mechanism in Acinetobacter baumannii. Pseudomonas extended-resistance (PER-1) type β-lactamaseproducing strains have been reported from various geographic locations; however, PER-1 type β-lactamases from Turkish hospitals have not been investigated extensively. The aim of this study was to determine the prevalence of PER-1 type β-lactamases in A. baumannii isolates in various regions of Turkey. Materials and methods: A total of 763 clinical A. baumannii isolates were collected from 9 university hospitals and 2 state hospitals between 2008 and 2011. Molecular amplification of the OXA-51 gene from the A. baumannii genome was performed in order to verify identification of the species. Real-time polymerase chain reaction was used to detect blaPER-1 genes. Results: PER-1 was detected in 24.6% of the isolates. The annual frequencies of the PER-1 enzyme were detected as 52.2%, 35.9%, and 8.3% in 2008, 2009, and 2010, respectively. PER-1 prevalence decreased gradually over time. The differences observed in PER-1 prevalence among the regions of Turkey were statistically significant (chi-square test; P > 0.001). Conclusion: These data demonstrate that the frequency of detection of PER-1 type β-lactamases in A. baumannii species has decreased in Turkey. However, the increased carbapenem resistance, together with multidrug resistance, has created a worrisome situation regarding this pathogen

Distribution of blaOXA genes in Acinetobacter baumannii strains: A multicenter study

Acinetobacter cinsi içerisinde hastane enfeksiyonlarının en önemli etkeni Acinetobacter baumannii’dir. Bu gram-negatif kokobasil, antimikrobiyal tedavide kullanılan çoğu antibiyotiğe dirençli olup aynı zamanda karbapenemlere de direnç geliştirme kapasitesindedir. Bu çalışmanın amacı, A.baumannii’nin OXA alt grupları için multipleks gerçek zamanlı polimeraz zincir reaksiyonu (qPCR) kiti tasarlamak ve Türkiye'nin farklı bölgelerinden toplanan A.baumannii izolatlarında OXA alt gruplarının dağılımını araştırmaktır. Çalışmaya, çeşitli illerdeki (Afyonkarahisar, Ankara, Bolu, Elazığ, Erzurum, Isparta, İstanbul, Kahramanmaraş, Konya, Sakarya, Van) 13 üniversite ve devlet hastanesinin mikrobiyoloji laboratuvarlarında, 2008-2011 tarihleri arasında izole edilen toplam 834 A.baumannii klinik izolatı dahil edilmiştir. İzolatlar, konvansiyonel yöntemler ve otomatize sistemler [Vitek2 (bioMerieux, ABD) ve Phoenix (BD Diagnostic, MD)] kullanıla- rak tanımlanmış; duyarlılık testleri otomatize sistemler ve disk difüzyon yöntemiyle yapılmıştır. Tüm örnek- lere blaOXA-51-like, blaOXA-23-like ve blaOXA-58-like genleri için qPCR uygulanmış; ayrıca, blaOXA-24-like geni araştırılmasında konvansiyonel PCR yöntemi kullanılmıştır. Çalışmamızda saptanan antibiyotik direnç oranları; amoksisilin-klavulanat için %96.8, siprofloksasin için %86.8, gentamisin için %74.7, amikasin için %71.7, sefaperazon-sulbaktam için %73.5, imipenem için %72.1 ve meropenem için %73 olarak izlenmiştir. Altı yüz iki (%72.2) izolat hem imipenem hem de meropeneme dirençli bulunmuştur. A.baumannii izolatları için en etkili antibiyotiğin, %100 duyarlılık oranı ile kolistin olduğu görülmüştür. İzolatların tümünde bla-geni pozitif bulunmuş; ancak blaOXA-24-like geni hiçbir izolatta gösterilememiştir. Toplam blaOXA-23- OXA-51-like ve blaOXA-58-like gen pozitiflikleri sırasıyla %53.7 ve %12.5 olarak saptanmıştır. Karbapeneme dirençli izolike latların blaOXA-23-like ve blaOXA-58-like gen pozitiflikleri ise sırasıyla %74.4 ve %17.3 olarak tespit edilmiştir. Yir- mi beş izolat hem blaOXA-23-like hem de blaOXA-58-like gen pozitifliği göstermiştir. blaOXA-24-like hariç, karbapeneme dirençli izolatların tamamında OXA tipi genler saptanmıştır. Çalışmaya katılan merkezlerin blaOXA-23- ve blaOXA-58-like gen pozitiflik oranları farklı bulunmuştur. Ek olarak, çalışma sürecinde blaOXA-58-like gen like pozitifliği azalırken, blaOXA-23-like gen pozitifliği ile birlikte karbapenem direncinin arttığı belirlenmiştir. So- nuç olarak, karbapenemler dahil antimikrobiyal tedavide kullanılan çoğu antibiyotiğe yüksek direnç gös- teren A.baumannii izolatlarının kolistine duyarlılığı devam etmektedir. Hem blaOXA-23-like hem de blaOXA-58- genleri karbapeneme dirençli A.baumannii klinik izolatlarında oldukça yaygın olmakla birlikte, yıllar için- like deki blaOXA-23-like pozitif izolatların artışı dikkat çekicidir. Günümüzde, hastane kaynaklı enfeksiyonların ön- lenmesi için dirençli bakterilerin hızlı tanısında, multipleks qPCR en uygun yöntemdir. Bu çalışmada geliştirilen multipleks qPCR kiti karbapeneme dirençli A.baumannii klinik izolatlarında blaOXA-23-like, blaOXA-58-like ve blaOXA-51-like genlerinin hızlı tanısı ve sıklığının ortaya konmasında yararlı olabilir.Acinetobacter baumannii is the most important agent of nosocomial infections within the Acinetobac- ter genus. This gram-negative coccobacillus is intrinsically resistant to many antibiotics used in antimic- robial therapy, and capable of developing resistance including carbapenems. The objective of this study was to develop a multiplex real time polymerase chain reaction (qPCR) kit for OXA subgroups in A.ba- umannii, and to investigate the distribution of OXA subgroups in A.baumannii strains isolated from ge- ographically different regions of Turkey. A total of 834 A.baumannii clinical isolates collected from diffe- rent state and university medical centers in 13 provinces (Afyonkarahisar, Ankara, Bolu, Elazig, Erzurum, Isparta, Istanbul, Kahramanmaras, Konya, Sakarya, Van) between 2008-2011, were included in the study. The isolates were identified by conventional methods and automated systems [Vitek2 (bioMeri- eux, ABD) and Phoenix (BD Diagnostic, MD)]. The susceptibility profiles of the isolates were studied with automated systems and standard disc diffusion method. All samples were subjected to qPCR to detect blaOXA-51-like, blaOXA-23-like and blaOXA-58-like genes. A conventional PCR method was also used to detect bla- gene. The resistance rates observed during the study period were as follows: 96.8% for amo- OXA-24-like xicillin-clavulanate, 86.8% for ciprofloxacin, 74.7% for gentamicin, 71.7% for amikacin, 73.5% for ce- faperozone-sulbactam, 72.1% for imipenem and 73% for meropenem. Six hundred and two (72.2 %) isolates were resistant to both imipenem and meropenem. Colistin was found to be the most effective antibiotic against A.baumannii isolates with 100% susceptibility rate. All isolates were positive for blaOXA- gene, however blaOXA-24-like gene could not be demonstrated in any isolate. Total positivity rates of 51-like blaOXA-23-like and blaOXA-58-like genes were found as 53.7% and 12.5%, respectively, while these rates we- re 74.4% and 17.3% in carbapenem-resistant isolates, respectively. Twenty-five isolates were positive for both blaOXA-23-like and blaOXA-58-like genes. All of the carbapenem-resistant isolates have OXA type genes with the exception of blaOXA-24-like gene. The positivity rates for blaOXA-23-like and blaOXA-58-like genes vari- ed for each center. In addition, there was a decrease in the frequency of blaOXA-58-like gene, however both blaOXA-23-like gene and carbapenem resistance rates increased during the study period. In conclusion, high rates of resistance to carbapenems were also remarkable but A.baumannii strains keep on sensiti- vity to colistin. Both blaOXA-23-like and blaOXA-58-like genes were shown to be widespread in carbapenem- resistant A.baumannii clinical isolates. However, blaOXA-23-like gene positive strains were increased throug- hout the study. Currently, multiplex qPCR is the best way for rapid diagnosis of resistant bacteria for pre- vention of hospital-acquired infections. The multiplex qPCR kit developed in this study could be useful for rapid diagnosis and identify the frequencies of blaOXA-23-like, blaOXA-51-like and blaOXA-58-like genes in car- bapenem-resistant A.baumannii clinical isolates

Distribution of blaOXA genes in Acinetobacter baumannii strains: A multicenter study

Acinetobacter cinsi içerisinde hastane enfeksiyonlarının en önemli etkeni Acinetobacter baumannii’dir. Bu gram-negatif kokobasil, antimikrobiyal tedavide kullanılan çoğu antibiyotiğe dirençli olup aynı zamanda karbapenemlere de direnç geliştirme kapasitesindedir. Bu çalışmanın amacı, A.baumannii’nin OXA alt grupları için multipleks gerçek zamanlı polimeraz zincir reaksiyonu (qPCR) kiti tasarlamak ve Türkiye'nin farklı bölgelerinden toplanan A.baumannii izolatlarında OXA alt gruplarının dağılımını araştırmaktır. Çalışmaya, çeşitli illerdeki (Afyonkarahisar, Ankara, Bolu, Elazığ, Erzurum, Isparta, İstanbul, Kahramanmaraş, Konya, Sakarya, Van) 13 üniversite ve devlet hastanesinin mikrobiyoloji laboratuvarlarında, 2008-2011 tarihleri arasında izole edilen toplam 834 A.baumannii klinik izolatı dahil edilmiştir. İzolatlar, konvansiyonel yöntemler ve otomatize sistemler [Vitek2 (bioMerieux, ABD) ve Phoenix (BD Diagnostic, MD)] kullanıla- rak tanımlanmış; duyarlılık testleri otomatize sistemler ve disk difüzyon yöntemiyle yapılmıştır. Tüm örnek- lere blaOXA-51-like, blaOXA-23-like ve blaOXA-58-like genleri için qPCR uygulanmış; ayrıca, blaOXA-24-like geni araştırılmasında konvansiyonel PCR yöntemi kullanılmıştır. Çalışmamızda saptanan antibiyotik direnç oranları; amoksisilin-klavulanat için %96.8, siprofloksasin için %86.8, gentamisin için %74.7, amikasin için %71.7, sefaperazon-sulbaktam için %73.5, imipenem için %72.1 ve meropenem için %73 olarak izlenmiştir. Altı yüz iki (%72.2) izolat hem imipenem hem de meropeneme dirençli bulunmuştur. A.baumannii izolatları için en etkili antibiyotiğin, %100 duyarlılık oranı ile kolistin olduğu görülmüştür. İzolatların tümünde bla-geni pozitif bulunmuş; ancak blaOXA-24-like geni hiçbir izolatta gösterilememiştir. Toplam blaOXA-23- OXA-51-like ve blaOXA-58-like gen pozitiflikleri sırasıyla %53.7 ve %12.5 olarak saptanmıştır. Karbapeneme dirençli izolike latların blaOXA-23-like ve blaOXA-58-like gen pozitiflikleri ise sırasıyla %74.4 ve %17.3 olarak tespit edilmiştir. Yir- mi beş izolat hem blaOXA-23-like hem de blaOXA-58-like gen pozitifliği göstermiştir. blaOXA-24-like hariç, karbapeneme dirençli izolatların tamamında OXA tipi genler saptanmıştır. Çalışmaya katılan merkezlerin blaOXA-23- ve blaOXA-58-like gen pozitiflik oranları farklı bulunmuştur. Ek olarak, çalışma sürecinde blaOXA-58-like gen like pozitifliği azalırken, blaOXA-23-like gen pozitifliği ile birlikte karbapenem direncinin arttığı belirlenmiştir. So- nuç olarak, karbapenemler dahil antimikrobiyal tedavide kullanılan çoğu antibiyotiğe yüksek direnç gös- teren A.baumannii izolatlarının kolistine duyarlılığı devam etmektedir. Hem blaOXA-23-like hem de blaOXA-58- genleri karbapeneme dirençli A.baumannii klinik izolatlarında oldukça yaygın olmakla birlikte, yıllar için- like deki blaOXA-23-like pozitif izolatların artışı dikkat çekicidir. Günümüzde, hastane kaynaklı enfeksiyonların ön- lenmesi için dirençli bakterilerin hızlı tanısında, multipleks qPCR en uygun yöntemdir. Bu çalışmada geliştirilen multipleks qPCR kiti karbapeneme dirençli A.baumannii klinik izolatlarında blaOXA-23-like, blaOXA-58-like ve blaOXA-51-like genlerinin hızlı tanısı ve sıklığının ortaya konmasında yararlı olabilir.Acinetobacter baumannii is the most important agent of nosocomial infections within the Acinetobac- ter genus. This gram-negative coccobacillus is intrinsically resistant to many antibiotics used in antimic- robial therapy, and capable of developing resistance including carbapenems. The objective of this study was to develop a multiplex real time polymerase chain reaction (qPCR) kit for OXA subgroups in A.ba- umannii, and to investigate the distribution of OXA subgroups in A.baumannii strains isolated from ge- ographically different regions of Turkey. A total of 834 A.baumannii clinical isolates collected from diffe- rent state and university medical centers in 13 provinces (Afyonkarahisar, Ankara, Bolu, Elazig, Erzurum, Isparta, Istanbul, Kahramanmaras, Konya, Sakarya, Van) between 2008-2011, were included in the study. The isolates were identified by conventional methods and automated systems [Vitek2 (bioMeri- eux, ABD) and Phoenix (BD Diagnostic, MD)]. The susceptibility profiles of the isolates were studied with automated systems and standard disc diffusion method. All samples were subjected to qPCR to detect blaOXA-51-like, blaOXA-23-like and blaOXA-58-like genes. A conventional PCR method was also used to detect bla- gene. The resistance rates observed during the study period were as follows: 96.8% for amo- OXA-24-like xicillin-clavulanate, 86.8% for ciprofloxacin, 74.7% for gentamicin, 71.7% for amikacin, 73.5% for ce- faperozone-sulbactam, 72.1% for imipenem and 73% for meropenem. Six hundred and two (72.2 %) isolates were resistant to both imipenem and meropenem. Colistin was found to be the most effective antibiotic against A.baumannii isolates with 100% susceptibility rate. All isolates were positive for blaOXA- gene, however blaOXA-24-like gene could not be demonstrated in any isolate. Total positivity rates of 51-like blaOXA-23-like and blaOXA-58-like genes were found as 53.7% and 12.5%, respectively, while these rates we- re 74.4% and 17.3% in carbapenem-resistant isolates, respectively. Twenty-five isolates were positive for both blaOXA-23-like and blaOXA-58-like genes. All of the carbapenem-resistant isolates have OXA type genes with the exception of blaOXA-24-like gene. The positivity rates for blaOXA-23-like and blaOXA-58-like genes vari- ed for each center. In addition, there was a decrease in the frequency of blaOXA-58-like gene, however both blaOXA-23-like gene and carbapenem resistance rates increased during the study period. In conclusion, high rates of resistance to carbapenems were also remarkable but A.baumannii strains keep on sensiti- vity to colistin. Both blaOXA-23-like and blaOXA-58-like genes were shown to be widespread in carbapenem- resistant A.baumannii clinical isolates. However, blaOXA-23-like gene positive strains were increased throug- hout the study. Currently, multiplex qPCR is the best way for rapid diagnosis of resistant bacteria for pre- vention of hospital-acquired infections. The multiplex qPCR kit developed in this study could be useful for rapid diagnosis and identify the frequencies of blaOXA-23-like, blaOXA-51-like and blaOXA-58-like genes in car- bapenem-resistant A.baumannii clinical isolates