Persistence of related bla-IMP-4 metallo-beta-lactamase producing Enterobacteriaceae from clinical and environmental specimens within a burns unit in Australia - a six-year retrospective study.

Background: To describe the clinical epidemiology, environmental surveillance and infection control interventions undertaken in a six-year persistence of bla-IMP-4 metallo-beta-lactamase (MBL) producing Enterobacteriaceae within a separately confined hospital burns unit in a tertiary hospital in Sydney, Australia.

Methods: MBL positive clinical and environmental isolates were collected from the Burns Unit, from the first detection of isolates in September 2006 to August 2012. Unit-acquired clinical isolates were included, and patient outcomes analyzed amongst those who acquired clinically significant infections.

Plasmids and bacterial strains mediating multidrug-resistant hospital-acquired infections are coresidents of the hospital environment.

Hospital-acquired infections (HAIs) are a global problem. The widespread use of antibiotics continues to exacerbate the problem giving rise to antibiotic-resistant bacteria both in and outside a clinical context. The general hospital environment is an obvious important focus for the selection and spread of multiresistant bacteria and a potential direct source of HAIs.

Tn6060, a transposon from a genomic island in a Pseudomonas aeruginosa clinical isolate that includes two class 1 integrons.

A 25,441-bp transposon was recovered from a Pseudomonas aeruginosa clinical isolate. While the transposition module was >99% identical to sequence of Tn1403, the element had been subject to rearrangements, with two In70.2-like class 1 integrons inserted into it in an unusual "tail-to-tail" configuration.