In vitro antibiotic susceptibility profile of Clostridium difficile excluding PCR ribotype 027 outbreak strain in Hungary.

Our study showed the antibiotic susceptibility profile of toxigenic Clostridium difficile isolated from nosocomial and community-acquired CDI between 2008 and 2010. MICs of 200 C. difficile strains were determined using E®test method in the case of erythromycin, clindamycin, moxifloxacin, rifampicin, and metronidazole. All strains were susceptible to metronidazole in the study period. Resistance rates to erythromycin, clindamycin and moxifloxacin were 31%, 29.5%, and 21.5%, respectively. In the case of rifampicin, the MIC range was quite wide, 11.5% of the tested strains proved to be highly resistant (MIC≥32 µg/ml) to rifampicin. When we compared these results with our earlier findings from 2006 to 2007, only minor changes in susceptibility over the time-periods could be observed in the case of erythromycin, clindamycin, moxifloxacin, and rifampicin, but metronidazole susceptibility did not show changes.

[Gram-negative bacteremia in neutropenic patients with hematologic disorders. Experiences with prophylactic use of fluoroquinolones]. / Gram-negatív bacteriaemia neutropeniás hematológiai betegekben. Tapasztalatok fluorokinolonprofilaxis alkalmazása kapcsán.

UNLABELLED: Gram-negative bacteremia remains a severe complication of neutropenia with a high mortality rate. For high-risk patients prophylactic use of fluoroquinolones is recommended as a preventive strategy. AIMS: To study the effect of fluoroquinolone prophylaxis on Gram-negative bacteremia. METHODS: In the retrospective survey Gram-negative bacteremic episodes occurring in a centre for hematology and stem cell transplantation were studied. Data from the year before and after instituting prophylaxis were compared with regard to the incidence of blood stream infections, spectrum of pathogens, rate of fluoroquinolone resistance and all cause mortality of affected patient population. RESULTS: Only a slight decrease in the incidence of Gram-negative bacteremia was seen (ARR: 0.024) after the introduction of fluoroquinolone prophylaxis. Spectrum of pathogens remained unchanged. However, the proportion of fluoroquinolone resistant Gram-negative isolates increased markedly (from 24% to 59%, p = 0.001), especially fluoroquinolone resistant E. coli strains became more prevalent (from 16% to 75%, p<0.001). All cause mortality at 7 and 30 days remained the same or increased insignificantly. CONCLUSIONS: With the current epidemiological background none of the expected benefits from the fluoroquinolone prophylaxis could be proven, whereas, the rate of fluoroquinolone resistance increased markedly. A reconsideration of present prophylactic strategies is suggested.

Rapid identification of pathogens in blood culture with fluorescent in situ hybridization (FISH).

Rapid identification of pathogens in bloodstream infections is of utmost importance to improve survival of septic patients. Fluorescent in situ hybridization (FISH) accelerates the identification of most frequent bacterial and yeast pathogens of sepsis. In this study, 210 positive blood cultures were tested with FISH method and the results were evaluated comparing to the traditional cultivation based results. Overall agreement between FISH and conventional identification was 91.4%, with better results for Gram-negative bacteria than for Gram-positives (100% and 89.5%, respectively). FISH results were obtained within 1 hour. FISH may serve as a useful tool to supplement traditional microbiological methods for rapid, provisional identification of sepsis pathogens.

Assessment of changes in the epidemiology of Clostridium difficile isolated from diarrheal patients in Hungary.

150 Clostridium difficile strains isolated from diarrheal feces were collected from three parts of Hungary and the presence of genes responsible for toxin A and B, and binary toxin production were examined. MIC distribution against clindamycin, erythromycin, metronidazole, moxifloxacin and rifampin of 80 toxigenic strains selected from the above-mentioned strains and 20 large clostridial toxins (LCTs)-positive strains chosen from our earlier strain collection were determined. 80% of the examined 150 strains were positive for both tcdA and tcdB, and no toxin A-negative, toxin B-positive isolates were found during the study period. 5.3% of toxigenic strains proved to be positive for binary toxin too. Among binary toxin-positive strains, one strain showed the same pattern characteristic of PCR ribotype 027. Comparison of recent findings and our earlier results, the prevalence of toxin-producing and binary toxin-positive strains among C. difficile isolated from diarrheal specimens increased. No metronidazole resistant isolate was detected among strains isolated in 2002-2003 and 2006-2007. The rates of resistance to erythromycin, clindamycin, moxifloxacin and rifampin among strains isolated between 2006 and 2007 were 25%, 27.5%, 25% and 6.3%, respectively. Erythromycin resistance was frequently associated with clindamycin and moxifloxacin resistance, however this resistant phenotype was not found among strains isolated in 2002-2003.

Molecular characterization of vancomycin-resistant Enterococcus spp. clinical isolates from Hungary and Serbia.

The objectives of this work were to collect and characterize vancomycin-resistant Enterococcus faecium (VREF) clinical isolates from Hungary and Serbia and to analyse their genetic relatedness. VREF isolates were initially typed by PFGE. A selection of VREF isolates representing all participating hospitals was further examined by multiple-locus variable-number tandem repeat analysis (MLVA) and multilocus sequence typing (MLST). VanB VREF isolates (n=18) recovered from blood, urine and faecal cultures at a Budapest hospital between August 2003 and December 2004 were molecularly characterized. Macrorestriction analysis of the isolates revealed their monoclonal relatedness. A cluster of infections caused by 2 distinct VanA VREF clones recovered from 6 departments was identified in a Belgrade hospital in Serbia. The vanA resistance determinant was transferable by in vitro conjugation experiments. We also identified 2 vanA-positive E. gallinarum blood culture isolates in this Belgrade hospital. Molecular typing of representative VREF isolates from Hungary and Serbia by MLVA and MLST revealed that all tested isolates belonged to MLST complex CC17 and the corresponding MLVA cluster 1. Our results extend the documented occurrence of CC17 to a new region in Europe.

Optimising antibiotic dosing regimens based on pharmacodynamic target attainment against Pseudomonas aeruginosa collected in Hungarian hospitals.

Owing to increasing resistance rates in Europe, pharmacodynamic analyses were proposed to determine optimal empirical antibiotic therapy against Pseudomonas aeruginosa isolated in Hungary. Minimum inhibitory concentrations for 180 non-duplicate P. aeruginosa collected from 14 hospitals in Hungary were determined by Etest methodology. A 5000-subject Monte Carlo simulation was performed to calculate the bactericidal cumulative fraction of response (CFR) for standard dosing regimens of cefepime, ceftazidime, ciprofloxacin, imipenem, meropenem and piperacillin/tazobactam. In the case of poor CFR, alternative dosage regimens were simulated for selected agents by increasing the infusion time, dose and frequency. Owing to high resistance rates in Hungary, no regimen achieved >90% CFR. CFRs for standard dosing regimens were: meropenem 1g every 8h (q8h), 77.1%; ceftazidime 2g q8h, 75.3%; imipenem 0.5 g every 6h (q6h), 71.7%; and piperacillin/tazobactam 4.5 g and 3.375 g q6h, 72.4% and 71.0%, respectively. Ciprofloxacin achieved significantly lower bactericidal CFRs than any beta-lactam. Prolonged infusion regimens improved the CFR for cefepime, imipenem, meropenem and piperacillin/tazobactam. Overall, the highest CFR (88.1%) was achieved by a 3-h infusion of meropenem 2g q8h. Given the poor CFR predicted with standard dosage regimens against these isolates, it seems prudent to consider alternative dosage strategies such as increasing doses, frequencies or infusion times as well as combination therapy when empirically treating infections caused by P. aeruginosa in Hungary.

[The first clinical experiences in Hungary with a new effective antibiotic (linezolid) effective against Gram-positive infections]. / Multirezisztens Gram-pozitív kórokozók ellen hatékony, új antibiotikummal (linezolid) szerzett elsó magyarországi tapasztalatok.

INTRODUCTION: The occurrence of gram-positive infections caused by multiresistant organisms has increased significantly in general, particularly among the surgical patients, and only a few effective antibiotics are available. A new and effective, synthetic antibiotic, against gram-positives is the oxazolidinon group, that electively inhibits bacterial protein synthesis in the early phase. Linezolid, the first member of this group to be used in clinical practice is the linezolid was studied. AIMS: The purpose of this study was to evaluate the effectiveness and safety of linezolid in the gram-positive infections of surgical patients. METHODS: A 3rd phase, clinical trial was conducted at the Semmelweis University Ist Surgical Department in the period of 1999-2001. Twenty-one patients with gram-positive infections were enrolled to this study. The mean of age was 57 years. Patients were selected for linezolid treatment in whom the conventional anti-gram-positive antibiotic therapy caused difficulties. RESULTS: Sixteen patients out of 21 recovered, one patient was cured clinically, but not microbiologically, and one case showed microbiological cure with clinical failure. In one case the methicillin resistant Staphylococcus aureus carriership was cured. Two cases had a fatal outcome. The causes of death were mediastinitis plus pneumonia in one case, and diffuse peritonitis with renal insufficiency in the other. Withdrawal from the study occurred in one case, due to drug intolerance. CONCLUSIONS: The linezolid administration proved to be safe and effective even in those cases, in which either hypacusis or decreased renal function persisted, or oral intake was advantagous. Contraindication of linezolid therapy did not occur. Few side effects were observed. If the infection was polymicrobial, the linezolid could be combined with other antibiotics. Further investigations are mandatory to evaluate the role of linezolid in the treatment of methicillin resistant Staphylococcus aureus carriership.