Occurrence of bacteria producing broad-spectrum beta-lactamases and qnr genes in hospital and urban wastewater samples.

The aims were to investigate the level of antibiotic-resistant bacteria in hospital and urban wastewater and to determine the similarity of isolates obtained from wastewater and hospitalized patients. Wastewater samples were collected in September 2013 and 2014. After identification using MALDI-TOF MS, beta-lactamase production was determined by relevant phenotypic tests. Genes responsible for the production of single beta-lactamase groups and Qnr proteins were established. The epidemiological relationship of the isolates from wastewater and hospitalized patients was determined by PFGE. A total of 51 isolates of enterobacteria were obtained. Overall, 45.1% of them produced broad-spectrum beta-lactamases. Genes encoding TEM, SHV, CTX-M, CIT, DHA and EBC types of enzymes and Qnr proteins were detected. No broad-spectrum beta-lactamase production was confirmed in the urban wastewater treatment plant. The most important finding was the detection of two identical isolates of K. pneumoniae in 2013, one from a patient's urinary catheter and the other from a wastewater sample.

Antibiotic consumption and its influence on the resistance in Enterobacteriaceae.

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.

[Effect of colistin consumption and prevalence of colistin-resistant bacteria]. / Vliv spotreby kolistinu na vyskyt kolistin-rezistentnich bakterii.

OBJECTIVE: Recently, there has been a renaissance of the use of the antibiotic colistin resulting from increasing resistance of bacterial pathogens, particularly in intensive care patients. The study aimed at assessing the impact of colistin consumption on the prevalence of colistin-resistant bacteria in the University Hospital Olomouc (UHO). METHODS: A laboratory database was retrospectively searched to identify all clinically significant colistin-resistant bacterial strains isolated between 2007 and 2011. These data were compared with colistin consumption over the same period and the results were statistically processed. RESULTS: Over the study period, a total of 6 338 clinically significant colistin-resistant strains were detected in the UHO (Acinetobacter spp., Burkholderia cepacia complex, Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp., Morganella morganii, Proteus spp., Providencia spp., Pseudomonas spp., Serratia marcesces and Stenotrophomonas maltophilia). Over the same period, the consumption of colistin increased nearly 10-fold. With the increasing colistin consumption, the numbers of colistin-resistant strains of Pseudomonas aeruginosa and Acinetobacter spp. decreased over that period of time. By contrast, there was an increase in the rates of naturally Burkholderia cepacia complex strains naturally resistant to colistin. An alarming finding is that the prevalence of colistin-resistant strains of Klebsiella pneumoniae increased in the last years of the study period, especially in intensive care patients. CONCLUSIONS: In the UHO, higher consumption of colistin was accompanied by increased numbers of colistin-resistant strains. There was a marked increase of Burkholderia cepacia complex strains and, recently, a statistically insignificant but alarming increase in colistin-resistant Klebsiella pneumoniae strains.