BACKGROUND: Increasing bacterial resistance to antibiotics is one of the most serious problems in current medicine. An important factor contributing to the growing prevalence of multiresistant bacteria is application of antibiotics. This study aimed at analyzing the development of resistance of Enterobacteriaceae to selected beta-lactam, fluoroquinolone and aminoglycoside antibiotics in the University Hospital Olomouc and assessing the effect of selection pressure of these antibiotics. METHODS: For the period between 1 January 2000 and 31 December 2011, resistance of Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae and Proteus mirabilis to third- and fourth-generation cephalosporins, meropenem, piperacillin/tazobactam, fluoroquinolones and aminoglycosides was retrospectively studied. For the assessment of selection pressure of antibiotics, a parameter of defined daily dose in absolute annual consumption (DDDatb) based on the ATC/DDD classification and in relative annual consumption (RDDDatb) as the number of defined daily doses per 100 bed-days was used. The relationship between frequency of strains resistant to a particular antibiotic and antibiotic consumption was assessed by linear regression analysis using Spearman's correlation. The level of statistical significance was set at p < 0.05. RESULTS: A total of 113,027 isolates from the Enterobacteriaceae family were analyzed. There was a significant effect of selection pressure of the primary antibiotic in the following cases: piperacillin/tazobactam in Klebsiella pneumoniae, gentamicin in Klebsiella pneumoniae and Escherichia coli and amikacin in Escherichia coli and Enterobacter cloacae. Also, there was significant correlation between resistance to ceftazidime and consumption of piperacillin/tazobactam in Klebsiella pneumoniae and Escherichia coli. No relationship was found between consumption of third- and fourth-generation cephalosporins and resistance to ceftazidime or between fluoroquinolone consumption and resistance to ciprofloxacin. CONCLUSION: The study showed the effects of both direct and indirect selection pressure on increasing resistance to gentamicin, amikacin, piperacillin/tazobactam and ceftazidime. Given the fact that no correlation was found between resistance to fluoroquinolones and consumption of either primary or secondary antibiotics, we assume that the increasing resistance to fluoroquinolones is probably due to circulation of resistance genes in the bacterial population and that this resistance was not affected by reduced use of these antibiotics.

• MeSH
• Aminoglycosides therapeutic use   MeSH
• Anti-Bacterial Agents therapeutic use   MeSH
• beta-Lactams therapeutic use   MeSH
• Enterobacter cloacae drug effects   isolation & purification   physiology   MeSH
• Enterobacteriaceae Infections drug therapy   microbiology   MeSH
• Escherichia coli drug effects   isolation & purification   physiology   MeSH
• Fluoroquinolones therapeutic use   MeSH
• Klebsiella pneumoniae drug effects   isolation & purification   physiology   MeSH
• Humans MeSH
• Linear Models MeSH
• Microbial Sensitivity Tests MeSH
• Drug Resistance, Multiple, Bacterial drug effects   MeSH
• Proteus mirabilis drug effects   isolation & purification   physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aminoglycosides MeSH
• Anti-Bacterial Agents MeSH
• beta-Lactams MeSH
• Fluoroquinolones MeSH

BACKGROUND: Enterobacteriaceae producing ESBL and AmpC enzymes can be associated with failure of antibiotic therapy and related morbidity and mortality. Their routine detection in microbiology laboratories is still a problem. The aim of this study was to compare the sensitivity of selected phenotypic methods. MATERIAL/METHODS: A total of 106 strains of the Enterobacteriaceae family were tested, in which molecular biology methods confirmed the presence of genes encoding ESBL or AmpC. In ESBL-positive strains, the sensitivity of the ESBL Etest (AB Biodisk) and a modified double-disk synergy test (DDST) were evaluated. AmpC strains were tested by a modified AmpC disk method using 3-aminophenylboronic acid. For simultaneous detection of ESBL and AmpC, the microdilution method with a modified set of antimicrobial agents was used. RESULTS: The sensitivity of the ESBL Etest was 95%; the modified DDST yielded 100% sensitivity for ESBL producers and the AmpC test correctly detected 95% of AmpC-positive strains. The sensitivity of the modified microdilution method was 87% and 95% for ESBL and AmpC beta lactamases, respectively. CONCLUSIONS: The detection of ESBL and AmpC beta lactamases should be based on specific phenotypic methods such as the modified DDST, ESBL Etest, AmpC disk test and the modified microdilution method.

• MeSH
• Anti-Infective Agents pharmacology   MeSH
• Bacterial Proteins analysis   MeSH
• beta-Lactamases analysis   MeSH
• Cephalosporins pharmacology   MeSH
• Enterobacteriaceae cytology   drug effects   enzymology   MeSH
• Phenotype MeSH
• Klebsiella pneumoniae cytology   drug effects   enzymology   MeSH
• Microbial Sensitivity Tests methods   MeSH
• Reference Standards MeSH
• Sensitivity and Specificity MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• AmpC beta-lactamases MeSH Browser
• Anti-Infective Agents MeSH
• Bacterial Proteins MeSH
• beta-Lactamases MeSH
• Cephalosporins MeSH

A 2-month survey of extended-spectrum beta-lactamase (ESBL) producers was performed in a Czech hospital. Klebsiella pneumoniae produced SHV-2, -5, or -12, Escherichia coli produced CTX-M-9 or -15, and other species produced TEM-92 or -132. All K. pneumoniae and E. coli isolates belonged to sequence types (STs) or clonal complexes (CCs) spread across the world (K. pneumoniae clonal complex 11 [CC11], CC14, and sequence type 101 [ST101] and E. coli CC31, CC73, CC131, and CC405) and carried various plasmids (mainly with A/C- and FII-type replicons).

• MeSH
• Anti-Bacterial Agents pharmacology   MeSH
• beta-Lactamases biosynthesis   chemistry   genetics   metabolism   MeSH
• DNA, Bacterial chemistry   genetics   MeSH
• Enterobacteriaceae Infections microbiology   MeSH
• Escherichia coli classification   enzymology   isolation & purification   MeSH
• Genotype MeSH
• Klebsiella pneumoniae classification   enzymology   isolation & purification   MeSH
• Humans MeSH
• Microbial Sensitivity Tests MeSH
• Hospitals MeSH
• Plasmids MeSH
• Bacterial Typing Techniques MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• Anti-Bacterial Agents MeSH
• beta-Lactamases MeSH
• DNA, Bacterial MeSH