ABSTRACT
Occurrence of carbapenemase-producing organisms, including New Delhi metallo-ß-lactamase-1 (NDM-1) is increasingly reported worldwide. The aim of this study was to assess the distribution of carbapenemase producers among multidrug-resistant Gram-negative bacteria isolated from blood cultures. All carbapenem-resistant strains collected from December 2011 to December 2012 were analyzed. Presence of carbapenemases was assessed with combined disc test and Carba NP test followed by polymerase chain reaction for carbapenemase genes. Altogether, 30 strains were detected, of which 7 were positive for VIM (23.3%), 6 for NDM-1 (20%), 5 for IMP (16.7%), and KPC was present in one isolate (3.3%). Four Pseudomonas aeruginosa strains were found to produce more than one carbapenemase. We also present the case report of a patient with Acinetobacter baumannii ventilator-associated pneumonia, followed by sepsis due to Enterococcus faecalis and pan-resistant NDM-1-producing P. aeruginosa. Despite the inappropriate therapy, the patient was successfully treated. This is the first report of NDM-1-producing strains in Slovakia and it contributes to a number of studies mapping the distribution of carbapenemase producers in Europe.
Subject(s)
Bacteremia/enzymology , Drug Resistance, Multiple, Bacterial , Gram-Negative Bacteria/enzymology , Gram-Negative Bacterial Infections/enzymology , beta-Lactamases/analysis , Acinetobacter Infections/drug therapy , Acinetobacter Infections/microbiology , Acinetobacter baumannii/isolation & purification , Adult , Anti-Bacterial Agents/therapeutic use , Bacteremia/epidemiology , Bacteremia/microbiology , Coinfection , Disk Diffusion Antimicrobial Tests , Drug Resistance, Multiple, Bacterial/genetics , Drug Therapy, Combination , Enterococcus faecalis/isolation & purification , Genes, Bacterial , Gram-Negative Bacteria/genetics , Gram-Negative Bacteria/isolation & purification , Gram-Negative Bacterial Infections/epidemiology , Gram-Negative Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/drug therapy , Gram-Positive Bacterial Infections/microbiology , Humans , Pneumonia, Ventilator-Associated/drug therapy , Pneumonia, Ventilator-Associated/microbiology , Pseudomonas Infections/drug therapy , Pseudomonas Infections/microbiology , Slovakia , beta-Lactamases/geneticsABSTRACT
BACKGROUND: The main mechanisms causing high-level resistance to fluoroquinolones (FQ) are encoded chromosomally; that includes mutations in genes coding DNA-gyrase, but overexpression of efflux pumps contributes to increased minimum inhibitory concentration (MIC) of FQ as well. However, genes responsible for FQ-resistance may be harboured in transferable/conjugative plasmids. For some time, there was an assumption that resistance to FQ cannot be transferable in conjugation due to their synthetic origin, until 1998, when plasmid-mediated resistance transmission in Klebsiella pneumoniae was proved. We aimed to detect the occurrence of transferable FQ-resistance among Gram- negative bacteria isolated from patients in Czech and Slovak hospitals. METHODS: In this study, we tested 236 clinical isolates of Gram-negative bacteria for transferable resistance. Among relevant isolates we performed PCR detection of transferable fluoroquinolone genes (qnr). RESULTS: We have observed transfer of determinants of cephalosporin-resistance, aminoglycoside resistance as well as FQ-resistance (in 10 cases; 4.24%) not only intra-species but inter-species too. The presence of qnr gene was detected in two isolates of forty tested (5%). We have also observed that determinants of cephalosporin-resistance and aminoglycoside-resistance were linked to those of FQ-resistance and were transferred en block in conjugation. CONCLUSION: We have proved that resistance to fluoroquinolones can be transferred horizontally via conjugation among Gram-negative bacteria of different species and is associated with resistance to other antibiotics.
