[Detection of plasmid-mediated AmpC beta-lactamase production in Escherichia coli and Klebsiella spp. isolates]. / Escherichia coli ve Klebsiella spp. izolatlarinda plazmid kaynakli AmpC beta-laktamaz üretiminin arastirilmasi

This study was conducted to obtain data about prevalence of plasmid-mediated AmpC (pAmpC), efficacy of various phenotypic tests applied for the detection of pAmpC-mediated resistance and the enzyme types responsible for this resistance. A total of 1316 isolates (1030 Escherichia coli and 286 Klebsiella spp.) obtained from the clinical samples sent to our laboratory between 2008-2011 period, from various inpatient and outpatient clinics and intensive care units, were included in this study. Antimicrobial susceptibility profiles of the isolates were determined by using Kirby-Bauer disk diffusion method. Production of pAmpC was phenotypically investigated by Boronic Acid Inhibition Test (BAIT), Cefoxitin Hodge Test (CHT) and AmpC Disk Test (ACDT) in a total of 36 (2.7%) cefoxitin-resistant isolates (77% were E.coli, 23% were K.pneumoniae); and by synergy tests with or without AmpC inhibitors in a total of 165 (88% were E.coli, 12% were K.pneumoniae) cefoxitin-susceptible, third generation cephalosporin-resistant (S3R) isolates. For the detection of pAmpC genes a multiplex-PCR protocol was applied to the isolates found positive at least by one of the phenotypic tests. CHT, ACDT and BAIT were found positive in 21 (58%), 18 (50%) and 7 (19%) of the 36 cefoxitin-resistant isolates, respectively. In only 10 (27.7%) of these isolates (all were E.coli strains), pAmpC presence was detected by PCR; and the enzyme produced was assessed as CMY-2. Based on the positive PCR results; specificity rates of the phenotypic tests, BAIT, ACDT and CHT were 97%, 69% and 58%; while the sensitivity rates were 50%, 100% and 100%, respectively. Our data indicated that, pAmpC prevalence (10/1316, 0.8%) detected in this study, did not seem to be an important problem yet, in the population screened. However, since the first detection of this resistance was in 2010, it should be considered as a sign to get necessary precautions preventing its spread. In conclusion, none of the phenotypic methods were satisfactory alone for the detection of pAmpC-mediated resistance; and BAIT was superior in terms of specificity while the others were superior in terms of sensitivity. Thus, combined application of these phenotypic tests are necessary to screen and confirm the presence of pAmpC-mediated resistance.

Does treatment affect the levels of serum interleukin-6, interleukin-8 and procalcitonin in diabetic foot infection? A pilot study.

AIMS: To investigate about serum PCT, IL-6 and IL-8 levels and how they are affected by the treatment in diabetic foot patients. METHODS: Fifty patients' blood samples were taken to study ESR and CRP, IL-6, IL-8 and PCT before and at the 14th day of the treatment. RESULTS: The pretreatment results of the 50 patients showed positive correlations between PCT and either ESH (r=0.49, p<0.001), or CRP (r=0.56, p<0.001). Similarly, there was a positive correlation between IL-6 and ESH (r=0.46, p=0.001), just like as it was between IL-6 and CRP (r=0.54, p<0.001). At the 14th day, the levels of ESR (70 ± 30.2 and 58.4 ± 26.2, p=0.02), CRP (63.8 ± 73.1 and 18.1 ± 19.7, p<0.001) and PCT (0.6 ± 2.1 and 0.05 ± 0.02, p=0.007) were significantly decreased while IL-6 was decreased at a close range to statistical significancy at healing patients (97.5 ± 147.2 and 47.1 ± 77.6; p=0.05), but they did not at nonhealing patients. IL-8 levels were not changed anyhow. CONCLUSIONS: PCT was significantly decreased such as ESR and CRP were in the early phase of healing; IL-6 and IL-8 levels were also decreased by the treatment, but not statistically significantly. IL-6 and PCT were affected in correlation with the other inflammatory parameters in the beginning, but IL-8 was not. PCT and IL-6 may be useful like CRP and ESR in the diagnosis and follow up of diabetic foot infection, but IL-8 is not. Further investigation is needed.

[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.