[In vitro susceptibility of methicillin-resistant Staphylococcus aureus isolates to vancomycin, teicoplanin, linezolide and daptomycin]. / Metisiline dirençli staphylococcus aureus izolatlarinin vankomisin, teikoplanin, linezolid ve daptomisine in vitro duyarliliklari.

In this study, vancomycin, teicoplanin, linezolide and daptomycin susceptibility rates of 67 methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained from various clinical samples between November 2006 and August 2010 in our laboratories, were investigated by E-test method and MIC values of the drugs were determined. Seventeen (25%) of the samples were from outpatient wards, 50 (75%) from inpatients of which 24 (48%) were from intensive care units. Distribution of MRSA isolated clinical samples were as follows: 16 (23.4%) blood, 28 (42.2%) wound swab, 15 (21.8%) tracheal aspirate, 2 (3.1%) urine, 2 (3.1%) urethral discharge, and one for each (1.6%) cerebrospinal fluid, joint fluid, catheter tip and nasal swab. Except one (1.5%) which was probably intermediate-resistant to vancomycin (since not confirmed by microdilution test or population analysis, this isolate was considered as "probable" intermediate-resistant), all of the isolates were found susceptible to all tested antibiotics. MIC(50) and MIC(90) values were determined as 0.75 and 1.5 µg/ml for vancomycin, 2 and 3 µg/ml for teicoplanin, 0.38 and 0.5 µg/ml for linezolide and 0.094 and 0.19 µg/ml for daptomycin, respectively. The MIC ranges were 0.25-3 µg/ml for vancomycin, 0.125-4 µg/ml for teicoplanin, 0.094-3 µg/ml for linezolide and 0.047-0.25 µg/ml for daptomycin. There was no statistically significant difference between MICs of outpatient, inpatient and intensive care unit isolates for any of the tested drugs (p> 0.05). Based on MIC90 values, daptomycin seems 4-16 times more effective than the other three drugs. It was concluded that considering their in-vitro antibacterial activity, these antibiotics can be used as alternatives to each other for the treatment of MRSA infections.

[Antibiotic resistance profiles of Acinetobacter species isolated from several clinical samples between 2007-2010]. / Çesitli klinik örneklerden 2007-2010 yillarinda izole edilen acinetobacter türlerinin antibiyotik direnç profilleri.

This study was aimed to investigate the changes in antibiotic resistance profiles of Acinetobacter spp. in our hospital during a four-year period. The study included a total of 465 non-duplicate Acinetobacter spp. isolated from various samples sent from intensive care (n= 274, 58.9%), inpatient (n= 141, 30.3%) and outpatient (n= 49, 10.5%) units of our hospital between 2007 and 2010. Sample distribution was as follows: 184 tracheal aspirates (39.5%), 70 blood (15.3%), 92 (19.8%) wound, 40 urine (8.6%), 24 sputum (5.1%), 22 (4.7%) bronchial lavage and 22 (4.7%) other (catheter tip, cerebrospinal fluid, thorasynthesis material) samples. The isolates were identified as A.baumannii (n= 340, 73.1%), A.lwoffii (n= 64, 13.7%) and Acinetobacter spp. (n= 61, 13.1%). The susceptibility profiles were investigated by Kirby-Bauer disc diffusion method. Overall, the results indicated an increase in resistance against all tested drugs since 2007. A steady increase of resistance from 2007 to 2009, followed by a tendency to decrease in 2010 was also noted for all drugs, except for ceftazidime (CAZ), trimethoprim-sulfomethoxazole (SXT), netilmicin (NET), imipenem (IPM), meropenem (MER) and gentamicin (CN). NET, IPM, cefepime and MER resistance rates increased regularly from 2007 to 2010. CAZ resistance followed a fluctuating course, while CN resistance displayed a decreasing trend since 2009. According to the statistical analyses (X2 and Fisher’s exact test), there was a regular resistance increase between 2007-2009 except for amikacin (AK), SXT and PIP. Resistance rates were also increased for AK and PIP, but only between 2007 and 2009; as well as for piperacillin-tazobactam, ticarcilin-clavulanate, NET, MER and IPM between 2008 and 2009. A significant increase from 2008 to 2010 was observed for NET; and a significant resistance decrease in 2010 was noted for only sultamicillin, cefotaxime, CN and tobramycin (TOB) (p< 0.05). As of 2010, the results indicated high resistance rates against ciprofloxacin [resistance rate (RR): 79%], NET (RR: 60%) and all beta-lactam drugs, including carbapenems (mean RR: 80%). Moreover, there was a progressive increase in resistance to carbapenems and NET, two very important treatment alternatives. Tigecycline (RR: 5.5%), TOB (RR: 19%), CN (RR: 34%) and cefoperazone-sulbactam (RR: 38%) appeared to remain as relatively effective treatment choices. The resistance rates of inpatient and outpatient isolates which were usually lower than those of the intensive care unit isolates, also displayed a noteworthy increase over the past four years. Evidently, pan-resistant Acinetobacter spp. will become a serious health problem in the near future, unless efficient and appropriate precautions are taken.