Clinical experience of serious infections caused by Enterobacteriaceae producing VIM-1 metallo-beta-lactamase in a Greek University Hospital.

Abstract

BACKGROUND:

The dissemination of acquired metallo-beta-lactamases (MBLs) in members of the family Enterobacteriaceae is regarded as an emerging clinical threat. The clinical characteristics and outcomes of 17 cases of infection due to MBL-producing isolates were analyzed.

METHODS:

During a 3-year period, medical records for all patients with confirmed infection due to an MBL-producing strain belonging to the Enterobacteriaceae family were retrospectively analyzed. We screened for MBL production with the imipenem-ethylenediaminetetraacetic acid disk synergy test, and results were confirmed by polymerase chain reaction. Genetic relatedness between isolates was evaluated by repetitive extragenic palindromic polymerase chain reaction.

RESULTS:

Fourteen cases of bacteremia and 3 cases of ventilator-associated pneumonia due to an MBL-producing isolate were studied. Most of the patients had previously been colonized with an MBL-producing organism, and almost 60% had been exposed to carbapenems before infection. The isolated pathogens (Klebsiella pneumoniae, 14 cases; and Klebsiella oxytoca, Enterobacter cloacae, and Enterobacter aerogenes, 1 case each) exhibited variable minimum inhibitor concentrations of carbapenems (1 to >32 microg/mL) and resistance to most other beta-lactams. Tigecycline was active against all isolates, whereas colistin and gentamicin were active against 88% of them. Molecular studies confirmed the presence of a gene belonging to bla(VIM-1) cluster in all isolates. Among the 12 K. pneumoniae isolates, which were subjected to molecular typing, 11 distinct clones were identified. Five cases ( approximately 30%) occurred in patients who were already receiving carbapenem-containing treatment, and carbapenem treatment was considered to have failed. Twelve cases were treated with a colistin-containing regimen. The attributable mortality rate was 18.8%.

CONCLUSIONS:

MBL-producing Enterobacteriaceae can cause severe, often fatal infection in severely ill patients, irrespective of the MIC of carbapenems. Colonization with an MBL-producer is a preceding event, highlighting the importance of surveillance. Both infection control practices and antibiotic policies should be intensified to contain the spread of these problematic bacteria.

• Authors: Maria Souli, Flora V Kontopidou, Evangelos Papadomichelakis, Irene Galani, Apostolos Armaganidis, Helen Giamarellou
• Journal: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America (Clin Infect Dis) Vol. 46 Issue 6 Pg. 847-54 (Mar 15 2008) ISSN: 1537-6591 [Electronic] United States
• PMID: 18269335 (Publication Type: Journal Article)

Chemical References

• VIM-1 metallo-beta-lactamase
• beta-Lactamases

Topics

• Adult
• Aged
• Aged, 80 and over
• Bacteremia (microbiology, mortality, physiopathology)
• Enterobacteriaceae (drug effects, enzymology, genetics, pathogenicity)
• Enterobacteriaceae Infections (microbiology, mortality, physiopathology)
• Female
• Greece (epidemiology)
• Hospitals, University
• Humans
• Klebsiella Infections (microbiology, mortality, physiopathology)
• Klebsiella pneumoniae
• Male
• Microbial Sensitivity Tests
• Middle Aged
• Pneumonia, Bacterial (microbiology, mortality, physiopathology)
• Polymerase Chain Reaction
• beta-Lactam Resistance
• beta-Lactamases (biosynthesis, genetics)