[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.

[In vitro synergistic effect of moxifloxacin and amphotericin B combination against Candida strains]. / Moksifloksasin ve amfoterisin b kombinasyonunun Candida türleri uzerine in vitro sinerjistik etkisi.

Contradictory results such as synergy or indifferent effect, have been reported about the interactions between quinolones and antifungal drugs in different studies. The aim of this study was to investigate the in vitro susceptibilities of Candida spp. to moxifloxacin (MOX) alone and MOX + amphotericin B (AmB) combination. A total of 20 strains were included to the study, of which 19 were clinical isolates (10 Candida albicans, 4 Candida glabrata, 2 Candida parapsilosis, 1 Candida tropicalis, 1 Candida pelliculosa ve 1 Candida sake) and 1 was a standard strain (C. albicans ATCC 90028). In vitro susceptibilities of the strains to MOX with AmB were investigated by broth microdilution method according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI), and in vitro interaction of these drugs were determined by a chequerboard titration method. Minimal inhibitory concentration (MIC) values of Candida spp. for MOX were found > or = 400 microg/ml indicating that MOX, by itself has no antifungal activity. AmB MIC values were found 1 microg/ml in 11 of the clinical isolates, and < or = 0.5 microg/ml in the other 8 clinical isolates and 1 standard strain. The inhibitor activity of AmB was slightly enhanced when combined with MOX, there being a decrease of 1-4 fold dilutions in the AmB MICs against all isolates tested. Synergistic effect between MOX and AmB, defined as a fractional inhibitory concentration (FIC) index as < or = 0.5, was observed in 90% (18/20; all were clinical isolates) of the strains, whereas indifferent effect (FIC = 1) was detected in 10% (2/20; 1 was clinical and 1 was standard strain) of the strains. Antagonistic effect was not observed for this combination even at 48th hours. It was concluded that these preliminary results should be confirmed by large-scaled in vitro and in vivo studies to evaluate MOX + AmB combination as a therapeutic option for the treatment of Candida infections.

The relationship between cervical human papillomavirus infection and apoptosis.

PURPOSE: Cervical carcinoma is the second most common cancer among women worldwide. Viral infections, especially human papillomavirus (HPV) infections, are important factors in its etiology. Changes in apoptotic regulation are considered to have an important role in the carcinogenesis development. In this study, the relationship between apoptosis and HPV infection was investigated. METHODS: HPV DNA and HPV DNA type 16 positivity were detected in 110 cervical smear samples with Real Time PCR and sequencing was performed for HPV DNA type 18. The presence of apoptosis was investigated using TUNEL and Annexin V staining methods and analyzed by fluorescence microscope and flow cytometry. RESULTS: HPV DNA type 16 was detected in 9 samples (8.1%), HPV DNA type 18 positive in 6 samples (5.4%) and HPV types other than HPV type 16 and HPV type 18 in 9 samples (8.1%). A decrease apoptosis was found in HPV DNA positive samples compared with controls (P < 0.05). CONCLUSION: The decrease of apoptosis during HPV infection might cause cellular immortality and then malignant transformation.

Effects of recombinant interferon-gamma on cytokine secretion from monocyte-derived macrophages infected with Salmonella typhi.

Salmonella typhi (S. typhi) is an important pathogen which causes typhoid fever. The cytokines released from the macrophages, playing a role in the host defense against Salmonella infection, are crucial in the defense against the infection. IFN-gamma provides a protection against Salmonella infection by developing macrophage activation in different mechanisms. This study was designed to investigate the effect of the recombinant IFN-gamma (rIFN-gamma) on the cytokines secreted from S. typhi stimulated macrophages. Macrophage isolation was done in the heparinized blood samples obtained from healthy people, and following the priming with rIFN-gamma for 72h the cells were stimulated by S. typhi and then the cytokine levels in culture supernatants were determined by enzyme-linked immunosorbent assay. It was observed that rIFN-gamma reversely increased the levels of IL-1, IL-2 the levels of which were decreased by S. typhi and that it increased TNF-alpha levels while suppressing the levels of antiinflammatory cytokines such as IL-10 and TGF-beta the levels of which were increased by S. typhi. Consequently, rIFN was observed to increase protective Th1 response by affecting the secretion of cytokine during S. typhi infection and it was considered to be a good target especially to prevent and treat invasive Salmonella infections.