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


RESULTS
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.


CONCLUSIONS
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.
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. mcubero@bellvitgehospital.cat.|Centro de Investigacion Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain. mcubero@bellvitgehospital.cat.
Meritxell
M
Cubero
Department of Infectious Diseases, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. guillermo.cuervos@bellvitgehospital.cat.
Guillermo
G
Cuervo
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. adominguez@bellvitgehospital.cat.|Spanish Network for Research in Infectious Diseases (RD06/0008), Instituto de Salud Carlos III, Madrid, Spain. adominguez@bellvitgehospital.cat.
M Ángeles
MÁ
Dominguez
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. f.tubau@bellvitgehospital.cat.|Centro de Investigacion Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain. f.tubau@bellvitgehospital.cat.
Fe
F
Tubau
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. smartinm@bellvitgehospital.cat.|Centro de Investigacion Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain. smartinm@bellvitgehospital.cat.
Sara
S
Martí
Department of Immunology, Microbiology, and Parasitology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Bizkaia, Spain. elena.sevillano@ehu.es.
Elena
E
Sevillano
Department of Immunology, Microbiology, and Parasitology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Bizkaia, Spain. lucia.gallego@ehu.es.
Lucía
L
Gallego
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. jayats@bellvitgehospital.cat.|Centro de Investigacion Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain. jayats@bellvitgehospital.cat.
Josefina
J
Ayats
Department of Infectious Diseases, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. cpena@bellvitgehospital.cat.|Spanish Network for Research in Infectious Diseases (RD06/0008), Instituto de Salud Carlos III, Madrid, Spain. cpena@bellvitgehospital.cat.
Carmen
C
Peña
Department of Infectious Diseases, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. mpujol@bellvitgehospital.cat.|Spanish Network for Research in Infectious Diseases (RD06/0008), Instituto de Salud Carlos III, Madrid, Spain. mpujol@bellvitgehospital.cat.
Miquel
M
Pujol
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. fina.linares@bellvitgehospital.cat.|Centro de Investigacion Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain. fina.linares@bellvitgehospital.cat.
Josefina
J
Liñares
Department of Microbiology, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL, Barcelona, Spain. c.ardanuy@bellvitgehospital.cat.|Centro de Investigacion Biomédica en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III, Madrid, Spain. c.ardanuy@bellvitgehospital.cat.
Carmen
C
Ardanuy
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015780:Carbapenems / Q000494:pharmacology*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D042822:Genomic Instability; D005838:Genotype; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing; D010957:Plasmids / Q000032:analysis; D012189:Retrospective Studies; D062606:Tertiary Care Centers; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D001618:beta-Lactamases; C063912:carbapenemase