CLONAL SPREAD OF MULTI-DRUG RESISTANT KLEBSIELLA PNEUMONIAE ISOLATES IN A LARGE TEACHING HOSPITAL IN THE UK

Abstract

Objective: To study hospital-wide dissemination of Extended Spectrum Beta-Lactamase (ESBL) producing

Klebsiella pneumonaie strains in a University Teaching Hospital in the West Midlands region of the UK.

Material and Methods: ESBL producing Klebsiella pneumonaie strains were isolated from patients

admitted to the study hospital during a two months period. Two Klebsiella pneumonaie NCTC strains,

10896 and 9633 were used as controls. Biotyping profiles were determined by using API 20E system (APIBioMerieux,

France) as per manufacturer's instructions. Initial susceptibility testing of the isolates was

performed by the BSAC disc diffusion method on IsoSensitest agar (ISA; Oxoid, Basingstoke, UK). ESBL

producing isolates were further tested by the BSAC broth dilution method using MIC breakpoint

susceptibility tests. Isolates were grown for 24 hours at 37 oC in 5 ml of Brain Heart infusion (BHI;

Oxoid, Basingstoke, UK). Restriction digestion of chromosomal DNA and Pulsed-field gel electrophoresis

(PFGE) were carried out.

Results: The sixteen clinical isolates from the study hospital clustered into two API biotype profiles. Their

antibiogram profile was similar except that eight isolates were resistant to ciprofloxacin in addition to

other antibiotics tested. There was no apparent correlation between the API profile and antibiogram among

these patients. Of the sixteen ESBL producing Klebsiella pneumoniae isolates from the study hospital, 9

were from urinary samples, 5 isolates were from sputum, and the remaining two strains were from blood

cultures. For the 20 clinical isolates and two control strains examined, 6 Xba 1 restriction patterns were

observed. The 16 clinical isolates from our hospital produced identical DNA profile. These were designated

as type A. The four unrelated isolates from a different hospital produced two DNA types designated as type

B and type C. The two control strains produced fragment patterns different to each other and to the

remainder of the isolates. These were designated as type E and type F .

Conclusion: This study emphasizes the need for continued surveillance of ESBL producing

enterobacteriacae. This will be helpful in monitoring antimicrobial resistance, and to guide intervention to

minimize its occurrence.