Staphylococcus aureus small-colony variants (SCVs) are being isolated more frequently in cystic fibrosis (CF) patients. We aimed to determine the prevalence of S. aureus SCVs and their phenotypic and genotypic properties in CF patients admitted to a university hospital. Specimens of 248 patients were examined during a period of 11 months. Colonies supposed to be SCVs were evaluated on Columbia blood agar, mannitol salt agar, and brain-heart infusion agar with 5% NaCl (BHIA 5% NaCl). Strains were confirmed by S. aureus nucA PCR. Antibiotic susceptibilities of SCVs and simultaneously isolated S. aureus strains were determined for oxacillin, gentamicin, trimethoprim-sulphamethoxazole, vancomycin, ciprofloxacin, linezolid, and tigecycline. Genetic relatedness between SCVs and normal S. aureus strains was determined with a pulsed-field gel electrophoresis (PFGE) method. S. aureus SCVs were detected in 20 of 248 patients (8.1%). The highest SCV isolation rate was obtained with MSA, followed by BHIA 5% NaCl. Auxotrophism for thymidine was demonstrated in six SCVs. The tigecycline susceptibilities of 48 SCV strains isolated in this study showed higher MIC values than those of 33 simultaneously isolated normal S. aureus strains. Whereas SCVs and normal S. aureus strains showed identical genotypes in 14 of the patients, five patients showed different genotypes. This first study from Turkey evaluating S. aureus SCVs in CF patients has indicated the importance of considering and reporting SCVs in chronic infections such as CF. The presence of SCVs will probably indicate persistent infection, and this might impact on antibiotic treatment decisions, as they are more resistant to antibiotics.
Aims This study was designed to investigate the penetration of second-, third-and fourthgeneration topical fluoroquinolone into aqueous and vitreous humour in a rabbit endophthalmitis model. Methods Thirty New Zealand white rabbits were divided into six groups. Left eye was infected with an intravitreal inoculum of Staphylococcus aureus. Groups 1, 2, 3, 4, and 5 received topical ofloxacin, ciprofloxacin, lomefloxacin, levofloxacin, or moxifloxacin treatment 24 h after the inoculation, respectively. No treatment was given to group 6 as the control group (n ¼ 5). Aqueous and vitreous samples were obtained 30 min after the last drop. High-performance liquid chromatography was used to determine the fluoroquinolone concentration. Results In the normal and inflamed eyes, mean aqueous concentrations of ofloxacin were 1.90 and 2.69 lg/ml, ciprofloxacin were 2.16 and 3.65 lg/ml, lomefloxacin were 3.54 and 1.19 lg/ml, levofloxacin were 2.89 and 9.41 lg/ ml, and moxifloxacin were 4.92 and 43.33 lg/ ml, respectively. Mean vitreous concentrations of ofloxacin were 0.25 and 0.07 lg/ml, ciprofloxacin were 0.08 and 0.32 lg/ml, lomefloxacin were 0.001 and 0.03 lg/ml, levofloxacin were 0.03 and 0.09 lg/ml, and moxifloxacin were 0.28 and 2.68 lg/ml, in normal and inflamed eyes, respectively. Moxifloxacin achieved a significantly higher concentration in aqueous and vitreous humour of infected eyes compared with ofloxacin (Po0.01), ciprofloxacin (Po0.05), lomefloxacin (Po0.01), and levofloxacin (Po0.05). Conclusion This study demonstrated that fourth-generation fluoroquinolone, moxifloxacin, seems to have better penetration to inflamed ocular tissues in rabbit.
BackgroundThe aim of this study was to determine the distribution of vancomycin and daptomycin MICs among methicillin-resistant Staphylococcus aureus (MRSA) blood isolates, the prevalence of heterogeneous vancomycin-intermediate S. aureus (hVISA) and the relationship between hVISA and vancomycin MIC values.MethodsA total of 175 MRSA blood isolates were collected from seven university hospitals in Turkey. All isolates were tested for susceptibility to vancomycin and daptomycin by reference broth microdilution (BMD) and by standard Etest method. BMD test was performed according to CLSI guidelines and Etest was performed according to the instructions of the manufacturer. All isolates were screened for the presence of the hVISA by using macro Etest (MET) and population analysis profile-area under the curve (PAP-AUC) methods.ResultsThe vancomycin MIC50, MIC90 and MIC ranges were 1, 2, and 0.5-2 μg/ml, respectively, by both of BMD and Etest. The daptomycin MIC50, MIC90 and MIC ranges were 0.5, 1 and 0.125 -1 μg/ml by BMD and 0.25, 0.5 and 0.06-1 μg/ml by Etest, respectively. The vancomycin MIC for 40.6% (71/175) of the MRSA isolates tested was >1 μg/ml by BMD. No vancomycin and daptomycin resistance was found among MRSA isolates. Percent agreement of Etest MICs with BMD MICs within ±1 doubling dilution was 100% and 73.1% for vancomycin and daptomycin, respectively. The prevalence of hVISA among MRSA blood isolates was 13.7% (24/175) by PAP-AUC method. MET identified only 14 of the hVISA strains (sensitivity, 58.3%), and there were 12 strains identified as hVISA that were not subsequently confirmed by PAP-AUC (specificity, 92.1%).ConclusionsAgreement between BMD and Etest MICs is high both for vancomycin and daptomycin. Daptomycin was found to be highly active against MRSA isolates including hVISA. A considerable number of isolates are determined as hVISA among blood isolates. As it is impractical to use the reference method (PAP-AUC) for large numbers of isolates, laboratory methods for rapid and accurate identification of hVISA need to be developed.
This paper reviews the species composition and distribution of Culicoides biting midges in Turkey for the first time. The
Acinetobacter baumannii is the most important agent of nosocomial infections within the Acinetobacter genus. This gram-negative coccobacillus is intrinsically resistant to many antibiotics used in antimicrobial 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.baumannii, and to investigate the distribution of OXA subgroups in A.baumannii strains isolated from geographically different regions of Turkey. A total of 834 A.baumannii clinical isolates collected from different 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 (bioMerieux, 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 blaOXA-24-like gene. The resistance rates observed during the study period were as follows: 96.8% for amoxicillin-clavulanate, 86.8% for ciprofloxacin, 74.7% for gentamicin, 71.7% for amikacin, 73.5% for cefaperozone-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-51-like, however blaOXA-24-like gene could not be demonstrated in any isolate. Total positivity rates of blaOXA-23-like and blaOXA-58-like genes were found as 53.7% and 12.5%, respectively, while these rates were 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 varied 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 sensitivity 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 throughout the study. Currently, multiplex qPCR is the best way for rapid diagnosis of resistant bacteria for prevention 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-lik...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.