Extended-spectrum beta-lactamase-producing Enterobacteriaceae at Middlemore Hospital

Aims. To review patients colonised or infected with extended-spectrum betalactamase-producing Enterobacteriaceae (ESBLPE) at Middlemore Hospital, Auckland, New Zealand. Methods. All patients who had an ESBLPE isolated at the Middlemore Hospital Microbiology Laboratory from January 2001 to June 2004 were included in this review. Results. ESBLPE were isolated from 132 patients during the review period. There were 12 patients colonised or infected with an ESBLPE in 2001, 34 in 2002, 43 in 2003, and 43 in the first 6 months of 2004. The isolates were Escherichia coli (n=56), Enterobacter spp. (n=55), and Klebsiella pneumoniae (n=21). ESBLPE were isolated from a wide range of specimens including peripheral blood in 18 patients. Thirtythree (25%) patients had an ESBLPE isolated within 48 hours of admission; seven of these patients were neither long-term care facility (LTCF) residents nor had hospital admissions in the previous 6 months. Thirty-one patients (23%) resided in a LTCF before their admission; four patients from the same LTCF had indistinguishable isolates. All isolates tested were susceptible to meropenem and imipenem. All but one isolate tested was susceptible to ertapenem, and all but two were susceptible to amikacin. Conclusions. Colonisation and infection due to ESBLPE are increasing at Middlemore Hospital and in the Auckland community. We expect this trend to continue. There is evidence to suggest transmission of ESBLPE both in the Auckland community and LTCFs. Antibiotics useful for treatment of patients with proven ESBLPE infection at Middlemore Hospital include amikacin or a carbapenem. Careful infection control practices and antibiotic prescribing will be necessary to reduce the rate of increase of ESBLPE colonisation and infection at Middlemore Hospital and in the Auckland community.