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Local epidemiology of ESBL and AmpC producing Enterobacteriaeceae seen in urine samples in Glasgow

Abstract number: P1253

Lansdell P.M., Boyes J., Khanna N., Hamouda A., Younes A.M., Amyes S.G.

Aims:

1Define the prevalence of AmpC/ESBL (extended spectrum b-lactam­ases) producing organisms in our urinary isolates.

2Compare the distribution of isolates for age, location and organism type.

3Identify common genotypes from community and hospital isolates.

Methods: Isolates were taken over a 12-week period from community and hospital urine samples received at our laboratory. The isolates underwent identification and antibiotic sensitivity testing as defined by the Health Protection Agency. Isolates resistant to amoxicillin and cephalexin had this confirmed by the Vitek2® system. Isolates sensitive to amoxicillin or cephalexin, or if they could not be identified by Vitek2®, were discarded. The final set then had their antibiograms confirmed using CLSI and Vitek2® methodologies. Phenotypic resistance mechanisms were identified using Vitek2®, HPA and MAST ID ESBL/AmpC methods. Of these ESBL and AmpC producing organisms a selection of underwent PCR genotyping.

Results: 9139 samples were processed of which 347 potential ESBL/AmpC producing isolates from 256 patients were identified. Of these isolates 219 were identified as E. coli, 56 as Klebsiella species, 30 Enterobacter species, 17 Serratia marcesans, 14 Citrobacter species, 8 Morganella morganii and 3 Proteus species. Amongst our E. coli 54.8% were phenotypically ESBLs, 16.9% were phenotypically AmpC producers and 3.2% showed duel mechanisms of resistance. We saw 116 isolates from the community and 231 isolates from inpatient locations. The predominant inpatient location was general medical wards. 53.3% of isolates were from the over 75 age group. A set of CTX-M ESBLs were genotyped; 90% were confirmed as CTX-M producers but only 60% were identified as being CTX-M-15, the commonest CTX-M type in the UK.

Conclusions: Our study shows almost 14% of our Enterobacteriaeceae are potential AmpC/ESBL producers, with over 80% confirmed phenotypically as producing either ESBL or AmpC or both. These organisms are seen most often in the over 75 age group and on general medical wards. In addition genotyping suggests common enzyme types in community and hospital isolates, raising concerns over treatment options for patients, with only parenteral antibiotics being available. In conclusion we feel current data on community and hospital prevalence, age distribution, resistance mechanism and organism type of ESBL/AmpC producers is lacking. We hope to raise awareness of these organisms and the impact they have on patient care.

OrganismNumber
(%)
ESBL
(%)
AmpC
(%)
Duel
(%)
Neg
(%)
E. coli219 (63.1)120 (54.8)37 (16.9)7 (3.2)55 (25.1)
Klebsiella species56 (16.1)49 (87.4)3 (5.4)1 (1.8)3 (5.4)
Enterobacter species30 (8.6)019 (63.3)9 (30)2 (6.7)
S. marcescens17 (4.9)2 (11.8)14 (82.4)01 (5.8)
Citrobacter species14 (4)2 (14.3)10 (71.4)2 (14.3)0
M. morganii8 (2.3)07 (87.5)1 (12.5)0
Proteus species3 (0.9)1 (33.3)2 (66.7)00
Total347174 (50.1)92 (26.5)20 (5.8)61 (17.6)

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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