[Occurrence of alert pathogens in hospital environment. Part I. ESBL-producing enterobacteriaceae strains]. / Wystepowanie patogenów alarmowych w srodowisku szpitalnym. Czesc I. Paleczki z rodziny Enterobacteriaceae wytwarzajace beta-laktamazy ESBL.

INTRODUCTION: Gram-negative bacteria belonging to the family Enterobacteriaceae cause severe and difficult to treat nosocomial infections. Strains of different species that produce extended-spectrum beta-lactamases (ESBL) were classified as alert pathogens. The purpose of this study was to analyze the occurrence and determination of antimicrobial susceptibility patterns of 134 ESBL-producing Enterobacteriaceae strains. METHODS: 96 (72%) isolates of Klebsiella pneumoniae and 38 (28%) isolates of Escherichia coli, were cultured from patients of Specialistic Hospital in Krakow, in the period from 2008 to 2010. Bacterial identification and antimicrobial susceptibility testing were performed by automated system Vitek 2 Compact (bioMerieux, Poland). Condition for inclusion in the study was the production by the strains of beta-lactamases with extended substrate spectrum (ESBL), which was confirmed using the automated method (Vitek 2 Compact system) and the disc-diffusion assay (DDST). Taken into consideration the first isolate from the patient. RESULTS: Bacilli of the species K. pneumoniae ESBL(+) were mainly isolated from respiratory tract samples (46%), urine (27%) and blood (12%). The dominant divisions in terms of frequency of isolation of these pathogens were anesthesiology and intensive care (42%), neurology and brain strokes (16%) and internal medicine (11%). Drugs with the highest efficiency against K. pneumoniae ESBL(+), in our in vitro studies, were: imipenem (100%), meropenem (100%), amikacin (90%) and tetracycline (75%). E. coli ESBL(+) isolates derived from patients of Anesthesiology and Intensive Care Unit (32%), Internal Medicine Unit (16%) and Division of Hematology (13%). Among all tested strains majority were obtained from respiratory tract samples, urine, swabs from wounds and blood (respectively 24%, 24%, 21% and 18%). Isolates of E. coli ESBL(+) demonstrated the greatest susceptibility in case of amikacin (92%) and piperacillin with tazobactam (76%), which suggests the highest activity of that antimicrobials against infections caused by examined strains. None of the analyzed bacilli were resistant to carbapenems. CONCLUSIONS: Our study highlights the importance of characteristics of distribution of ESBL-producing K. pneumoniae and E. coli strains among hospitalized patient. Good antibiotic policies based on antibiotic resistant patterns can decrease the risk of ESBL infection.

[Occurrence of alert pathogens in hospital environment Part II. Multidrug-resistant non-fermenting bacilli]. / Wystepowanie patogenów alarmowych w srodowisku szpitalnym. Czesc II. Wielolekooporne paleczki niefermentujace.

INTRODUCTION: Multidrug-resistant gram-negative non-fermenting bacilli are an important cause of nosocomial infection. Aim of this study was to analyze the prevalence and antimicrobial susceptibility of rods of the species Acinetobacter baumannii and Pseudomonas aeruginosa, belonging to multidrug-resistant alert pathogens. METHODS: 105 (70%) strains of A. baumannii and 46 (30%) strains of P. aeruginosa were isolated from 125 patients hospitalized in the Specialistic Hospital in Krakow, in the years 2008-2010. Taken into account first isolate from the patient. The condition for inclusion in the study was the resistance or reduced susceptibility to selected groups of antibiotics, such as beta-lactams, aminoglycosides and fluoroquinolones. Bacterial identification and antimicrobial susceptibility testing were performed by automated system Vitek 2 Compact (bioMerieux, Poland). All strains were tested with phenotypic method Etest MBL (AB Biodisk, Sweden) for the presence of resistance mechanism associated with the production of metallo-beta-lactamases. RESULTS: Bacilli of the species A. baumannii were isolated most frequently from patients from the Department of Anesthesiology and Intensive Care (52%) and Burn Therapy Unit (25%), with clinical materials collected from the respiratory tract (51%), the wound swabs (18%), urine (11%) and blood (11%). Production of metallo-beta-lactamases was found in 24 (22.9%) strains of A. baumannii. Drugs effective against multidrug-resistant isolates of A. baumannii were colistin and amikacin. Department of anesthesiology and intensive care (59%) and unit of internal medicine (11%) were the main source of multidrug-resistant strains of P. aeruginosa. Pathogens were mainly isolated from clinical specimens collected from the respiratory tract (61%), urine (15%) and wound swabs (13%). Seven (15.2%) strains of P. aeruginosa produced the metallo-beta-lactamases. With regard to colistin and piperacillin with tazobactam was noted the highest percentage of susceptible isolates. CONCLUSIONS: MDR bacteria belonging to alert pathogens are an important cause of many severe and difficult to treat infections which greatly increases the morbidity and mortality among hospitalized patients worldwide. Epidemiological studies and detection of local resistance patterns can provide useful information which can be used in the development of strategies to combat the rising tide of microbial antibiotic resistance.