Klebsiella pneumoniae ESBL, a protracted outbreak

Abstract number: P1651

Lytsy B., Melhus Å., Artinger C., Aspevall O., Eriksson B., Günther G., Hambraeus A., Ransjö U.

Objectives: Increasing numbers of multi-resistant K. pneumoniae isolates were found during May-Aug 2005 in Uppsala University Hospital, predominantly in urinary samples. The objective of the study was to identify risk factors for colonisation, develop screening strategies, and to reduce spread of resistant Enterobacteriaceae.

Methods: Isolates were typed with PhenePlate and PFGE, and belonged to a single clone, producing CTXM-15. Numbers of new cases were few after November 2005, but increased greatly during June-August 2006. The hospital then formed a Klebsiella ESBL steering group and working group with representatives from Microbiology, Infectious disease, Infection control, and Hospital administration.

Interventions used to terminate the outbreak:

–Placing cases with urinary catheters, diarrhoea, and/or discharging wounds in single rooms

–Enforced contact precautions for all levels of staff: short-sleeved working clothes, alcohol hand disinfection before and after any patient contact, gloves and plastic aprons at risk of soilage.

–Emphasis on hand hygiene for patients and visitors.

–Antimicrobial stewardship

To improve case-finding, screening strategies were developed, concentrating on stool samples from all patients in all wards, using selective media and PCR for CTXM group 1.

Results: Over 40 000 screening samples were taken Oct 2006-Aug 2007.

From May 2005 to September 2007, 257 patients were found to carry the outbreak strain in >50 different wards and departments, but not in intensive care units. A case-control study identified naso-gastric feeding, urinary tract catheters, diarrhoea, surgery, and use of third-generation cephalosporins/fluoroquinolons/ carbapenems as independent risk factors.

During June-Aug 2007, only 4 new clinical cases occured, as compared to 41 during June-Aug 2006. Use of hand alcohol increased from 31 to 81 ml/ per patient day. Improved compliance with contact precautions was observed. Cephalosporin use was reduced from approx 12000 to 4000 DDD/ six months. New patient beds were opened and staffing increased, to reduce overcrowding in risk wards. The cost of the outbreak is estimated at 3 million EUR.

Conclusion: When cases do not seem to be related in time and space, and most patients are only colonised, an outbreak can become very large before it is recognised. Joint efforts are needed to control such an outbreak, focussing on hand hygiene for patients and staff, reduction of overcrowding, and antimicrobial stewardship.