Carbapenem-resistant and carbapenem-susceptible isogenic isolates of Klebsiella pneumoniae ST101 causing infection in a tertiary hospital

• Published in: BMC microbiology Vol. 15; no. 1; p. 177
• Main Authors: Cubero, Meritxell, Cuervo, Guillermo, Dominguez, M Ángeles, Tubau, Fe, Martí, Sara, Sevillano, Elena, Gallego, Lucía, Ayats, Josefina, Peña, Carmen, Pujol, Miquel, Liñares, Josefina, Ardanuy, Carmen
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 03.09.2015; BioMed Central
• Subjects: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antibiòtics betalactàmics; Bacterial Proteins - genetics; Bacterial Proteins - secretion; Beta lactam antibiotics; beta-Lactam Resistance; beta-Lactamases - genetics; beta-Lactamases - secretion; Carbapenems - pharmacology; Cross Infection - epidemiology; Cross Infection - microbiology; Disease Outbreaks; Drug resistance; E coli; Electrophoresis, Gel, Pulsed-Field; Epidemiology; Female; Genomes; Genomic Instability; Genotype; Hospitals; Humans; Infeccions; Infections; Klebsiella Infections - epidemiology; Klebsiella Infections - microbiology; Klebsiella pneumoniae; Klebsiella pneumoniae - classification; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - enzymology; Klebsiella pneumoniae - genetics; Male; Medicaments antibacterians; Microbial Sensitivity Tests; Middle Aged; Molecular Typing; Plasmids - analysis; Resistència als medicaments; Retrospective Studies; Tertiary Care Centers; Spain; France
• ISSN: 1471-2180; 1471-2180
• DOI: 10.1186/s12866-015-0510-9

In this study we describe the clinical and molecular characteristics of an outbreak due to carbapenem-resistant Klebsiella pneumoniae (CR-KP) producing CTX-M-15 and OXA-48 carbapenemase. Isogenic strains, carbapenem-susceptible K. pneumoniae (CS-KP) producing CTX-M-15, were also involved in the outbreak. From October 2010 to December 2012 a total of 62 CR-KP and 23 CS-KP were isolated from clinical samples of 42 patients (22 had resistant isolates, 14 had susceptible isolates, and 6 had both CR and CS isolates). All patients had underlying diseases and 17 of them (14 patients with CR-KP and 3 with CS-KP) had received carbapenems previously. The range of carbapenem MICs for total isolates were: imipenem: 2 to >32 μg/ml vs. <2 μg/ml; meropenem: 4 to >32 μg/ml vs. <2 μg/ml; and ertapenem: 8 to >32 μg/ml vs. <2 μg/ml. All the isolates were also resistant to gentamicin, ciprofloxacin, and cotrimoxazole. Both types of isolates shared a common PFGE pattern associated with the multilocus sequence type 101 (ST101). The bla CTX-M-15 gene was detected in all the isolates, whereas the bla OXA-48 gene was only detected in CR-KP isolates on a 70 kb plasmid. The clonal spread of K. pneumoniae ST101 expressing the OXA-48 and CTX-M-15 beta-lactamases was the cause of an outbreak of CR-KP infections. CTX-M-15-producing isolates lacking the bla OXA-48 gene coexisted during the outbreak.