ABSTRACT
The purpose of this study was to quantify the impact of Staphylococcus haemolyticus in the epidemiology of the blood stream infection (BSI) and to characterize the rates and quantitative levels of resistance to antistaphylococcal drugs. During an eight-year period, 2967 BSIs of the patients hospitalized in different clinical departments of the Semmelweis University, Budapest, Hungary were analyzed. One hundred eighty-four were caused by S. haemolyticus, amounting to 6% of all infections. The antibacterial resistance of S. haemolyticus isolates was investigated by the broth microdilution method, vancomycin agar screen, population analysis profile and PCR for mecA, vanA and vanB genes detection. Epidemiological investigation was processed by determining phenotypic antibiotic resistance patterns and PFGE profiles. Extremely high MIC levels of resistance were obtained to oxacillin, erythromycin, clindamycin, gentamicin and ciprofloxacin. The incidence of teicoplanin reduced susceptibility revealed 32% without possessing either the vanA or vanB gene by the strains. PFGE revealed 56 well-defined genotypes indicating no clonal relationship of the strains. The propensity of S. haemolyticus to acquire resistance and its pathogenic potential in immunocompromised patients, especially among preterm neonates, emphasise the importance of species level identification of coagulase-negative staphylococci and routinely determine the MIC of proper antibacterial agents for these isolates.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteremia/epidemiology , Drug Resistance, Bacterial , Methicillin/pharmacology , Staphylococcal Infections/epidemiology , Staphylococcus haemolyticus/drug effects , Teicoplanin/pharmacology , Adult , Bacteremia/microbiology , Bacterial Proteins/genetics , Bacterial Typing Techniques , Electrophoresis, Gel, Pulsed-Field , Hospitals, University , Humans , Hungary , Infant , Infant, Newborn , Microbial Sensitivity Tests/methods , Molecular Typing , Polymerase Chain Reaction/methods , Staphylococcal Infections/microbiology , Staphylococcus haemolyticus/isolation & purificationABSTRACT
The extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp. cause worldwide problems in intensive care units. The aim of this study was to investigate the molecular epidemiology of ESBL-producing Klebsiella pneumoniae and K. oxytoca strains in a neonatal intensive care unit (NICU) in Budapest, Hungary and to determine the risk factors of the infections and the epidemiological features. Infections with Klebsiella spp. were analyzed retrospectively by reviewing the medical records between January 2001 and December 2005. Antibiotic susceptibility tests, isoelectric focusing, pulsed field gel electrophoresis, plasmid analysis, PCR for bla(TEM) and bla(SHV) and DNA sequencing analysis were performed on ESBL-producing Klebsiella isolates. A total of 45 babies were found to be infected with non-ESBL-producing Klebsiella spp. and 39 with ESBL-producing Klebsiella spp. Of the parameters analyzed, including sex, gestational age, twin pregnancy, birth weight, presence of central vascular catheter, mechanical ventilator use, parenteral nutrition, polymicrobial infection, caesarean section, transfusion and mortality, we found no statistically significant difference between the ESBL and the non-ESBL groups, or between the K. pneumoniae and K. oxytoca species. Further characterization of the ESBL-producing K. pneumoniae and K. oxytoca strains isolated between February 2001 and January 2003 revealed three distinct PFGE patterns of SHV-5-producing K. pneumoniae (A, B, E) and two distinct patterns of SHV-12-producing K. oxytoca (C,D) isolates; these had different plasmid profiles. From July to November 2005, a new SHV-5 producing K. oxytoca (F) was isolated. The molecular epidemiology of ESBL-producing organisms in a NICU over time shows substantial shifts in predominant strains. The ESBL production of the infected organisms has an impact on the survival of newborn babies with infections caused by Klebsiella spp.
