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The aims of this study were to determine the minimum inhibitory concentration (MIC) values of vancomycin, teicoplanin, daptomycin, quinupristin/dalfopristin, linezolid, tigecycline, chloramphenicol, rifampicin, ofloxacin and tetracycline and to investigate the reduced vancomycin susceptibility among methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in hospitals located in different geographical regions of Turkey. A total of 100 MRSA strains isolated from patients (of which 50% were from intensive care units) hospitalized in seven centers in Turkey [Istanbul (n= 15), Ankara (n= 15), Izmir (n= 15), Adana (n= 15), Diyarbakir (n=15), Erzincan (n= 15), Van (n= 10)], between August 201 3 August 2014, were included in the study. Fourty-three strains were isolated from blood, whereas 21 were from lower respiratory tract, 17 from wounds, eight from catheters, six from urine, four from nasal swab and one from cerebrospinal fluid samples. Methicillin resistance of the isolates was determined by using cefoxitin (30 mu g) disk with standard disk diffusion method, while the MIC values of other antibiotics were determined with E-test in accordance with the recommendations of Clinical and Laboratory Standards Institute (CLSI). MIC results obtained for quinupristin-dalfopristin (Q/D) were evaluated according to the CLSI criteria used for methicillin-susceptible S.aureus and for tigecycline according to the criteria recommended by the Food and Drug Administration for MRSA. Primarily, agar screening method (ASM) was used for determination of vancomycin-intermediate S.aureus (VISA) and heterogeneous VISA (hVISA) strains. Brain heart infusion agar containing 6 mu g/ml vanconnycin was used in ASM, and the strains with suspicion of VISA/hVISA were screened by standard E-test and macro E-test methods. All MRSA strains were susceptible to vancomycin, teicoplanin, daptomycin, Q/D and linezolid by E-test method; and their rates of susceptibility for tigecycline, chloramphenicol, rifampicin, ofloxacin and tetracycline were detected as 89%, 97%, 40%, 39% and 32%, respectively. MIC50/MIC90 values were 1.5/2 mu g/ml for vancomycin, 2/4 mu g/ml for teicoplanin, 0.19/0.38 mu g/ml for daptomycin, 0.19/0.38 mu g/ml for Q/D, 0.75/1 mu g/ml for linezolid, 0.19/0.75 mu g/ml for tigecycline, 3/6 mu g/ml for chloramphenicol, 32/32 mu g/ml for rifampicin, 32/32 mu g/ml for ofloxacin and 32/64 mu g/ml for tetracycline, respectively. For the evaluation of reduced vancomycin susceptibility, 2% (2/100) of MRSA strains were defined as VISA and 5% (5/100) as hVISA with ASM. One of those seven isolates identified as VISA/hVISA with ASM was evaluated as suspected hVISA by using both standard E-test and macro E-test methods. In conclusion, no MRSA resistant strain to vancomycin, teicoplanin, daptomycin, Q/D and linezolid was determined in our study. However tigecycline resistance (11%) was found higher than expected. As the glycopeptide resistance is increasing in the world and because of the intense use of these drugs in Turkey, the rates of vancomycin resistance among MRSA strains should be investigated periodically.

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 bla(OXA-51-like), bla(OXA-23-like) and bla(OXA-58-like) genes. A conventional PCR method was also used to detect bla(OXA-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 bla(OXA-51-like) gene, however bla(OXA-24-like) gene could not be demonstrated in any isolate. Total positivity rates of bla(OXA-23-like) and bla(OXA-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 bla(OXA-23-like) and bla(OXA-58-like) genes. All of the carbapenem-resistant isolates have OXA type genes like with the exception of bla(OXA-24-like) gene. The positivity rates for bla(OXA-23-like) and bla(OXA-58-like) genes varied for each center. In addition, there was a decrease in the frequency of bla(OXA-58-like) gene, however both bla(OXA-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 bla(OXA-23-like) and bla(OXA-58-like) genes were shown to be widespread in carbapenem-resistant A.baumannii clinical isolates. However, bla(OXA-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 bla(OXA-23-like), bla(OXA-51-like) and bla(OXA-58-like) genes in carbapenem-resistant A.baumannii clinical isolates.