ABSTRACT
Introduction. Identification of non-O157 Shiga-toxin-producing Escherichia coli (STEC) infections may be underestimated in microbiological diagnosis. Case presentation. A 58-year-old woman developed diarrhoea with watery and subsequently mucous stool. Initial multiplex PCR testing revealed a positive result for stx2 . Culture isolation of a STEC was successful only after repeated inoculation of chromogenic E. coli media. Molecular characterization was performed and identified the isolate as stx2e-positive STEC of serotype O8â:âH19. The strain harboured lpfA, but not eae. Conclusion. This case highlights the usefulness of initial multiplex PCR for diagnosis of non-O157 STEC infection.
ABSTRACT
Rapid diagnosis of bloodstream infections remains a challenge for the early targeting of an antibiotic therapy in sepsis patients. In recent studies, the reliability of the Nanosphere Verigene Gram-positive and Gram-negative blood culture (BC-GP and BC-GN) assays for the rapid identification of bacteria and resistance genes directly from positive BCs has been demonstrated. In this work, we have developed a model to define treatment recommendations by combining Verigene test results with knowledge on local antibiotic resistance patterns of bacterial pathogens. The data of 275 positive BCs were analyzed. Two hundred sixty-three isolates (95.6%) were included in the Verigene assay panels, and 257 isolates (93.5%) were correctly identified. The agreement of the detection of resistance genes with subsequent phenotypic susceptibility testing was 100%. The hospital antibiogram was used to develop a treatment algorithm on the basis of Verigene results that may contribute to a faster patient management.
Subject(s)
Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Bacteremia/drug therapy , Bacteremia/microbiology , Drug Resistance, Bacterial , Oligonucleotide Array Sequence Analysis/methods , Algorithms , Bacteremia/diagnosis , Gram-Negative Bacteria/classification , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/genetics , Gram-Positive Bacteria/classification , Gram-Positive Bacteria/drug effects , Gram-Positive Bacteria/genetics , Humans , Microbial Sensitivity Tests , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Extended spectrum of ß-lactam (ESBL) resistance of Klebsiella pneumoniae has become an increasing problem in hospital infections. Typing of isolates is important to establish the intrahospital surveillance of resistant clones. In this study, the discriminatory potential of randomly amplified polymorphic DNA and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analyses were compared with multilocus sequence typing (MLST) by using 17 ß-lactam-resistant K. pneumoniae isolates of different genotypes. MLST alleles were distributed in 8 sequence types (STs). Among ESBL strains of the same ST, the presence of different ß-lactamase genes was common. RAPD band patterns also revealed 8 types that corresponded to MLST-defined genotypes in 15 out of 17 cases. MALDI-TOF analysis could differentiate 5 clusters of strains. The results of this work show that RAPD may be usable as a rapid screening method for the intrahospital surveillance of K. pneumoniae, allowing a discrimination of clonally related strains. MALDI-TOF-based typing was not strongly corresponding to genotyping and warrants further investigation.