Extended-spectrum beta-lactamase-producing Enterobacteriaceae in hospital urinary tract infections: incidence and antibiotic susceptibility profile over 9 years.
OBJECTIVE
Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are an increasing concern regarding antibiotic resistance and their potential to cause serious infections which are difficult to treat. The purpose of this surveillance programme was to assess the incidence of ESBL in adults amongst urinary isolates, identify risk factors, and detail the antibiotic susceptibility profile in order to guide empirical treatment.


METHODS
From 2006 to 2014, we reviewed 21,414 positive urine cultures for E. coli and Klebsiella sp. from a University hospital in the UK and found 1420 ESBL-positive specimens. Susceptibility testing was performed by British Society of Antimicrobial Chemotherapy disc diffusion testing. ESBL screening was performed on samples resistant to cefpodoxime and confirmed by double disc diffusion (Oxoid Ltd, Basingstoke, UK). Patient gender, age, inpatient status, and catheterisation were assessed as risk factors.


RESULTS
ESBL production amongst E. coli urine cultures increased 44 %, from 4.6 to 6.6 % of all E. coli isolates. ESBL-positive organisms were associated with increases in drug resistance, particularly amongst fluoroquinolones, trimethoprim, and cephalexin. Multidrug resistance was a feature with 75 % of ESBL+ Klebsiella sp.-resistant ≥6 antibiotic classes. ESBL producers remained largely susceptible to carbapenems. Male gender, urinary catheterisation, inpatient status, and increasing age were identified as risk factors for ESBL infection or colonisation.


CONCLUSIONS
We demonstrate that the incidence of ESBL-producing E. coli in urine cultures is increasing and that such isolates are multidrug resistant. Carbapenems and nitrofurantoin for E. coli infections remain effective, which may guide empirical antibiotic therapy.
Urology Unit, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia. liam.toner@yahoo.com.|Urology Research Office, Level 8 Harold Stokes Building, Austin Hospital, 145 Studley Road, Heidelberg, VIC, 3084, Australia. liam.toner@yahoo.com.
Liam
L
Toner
Urology Unit, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia.
Nathan
N
Papa
Department of Microbiology, Addenbrookes' Hospital, Cambridge University, Cambridge, UK.
Sani H
SH
Aliyu
Department of Urology, Addenbrookes' Hospital, Cambridge University, Cambridge, UK.
Harveer
H
Dev
Urology Unit, Department of Surgery, University of Melbourne, Melbourne, VIC, Australia.|Olivia Newton-John Cancer Research Institute, Austin Health, Melbourne, VIC, Australia.|Department of Surgical Oncology, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia.
Nathan
N
Lawrentschuk
Department of Urology, Addenbrookes' Hospital, Cambridge University, Cambridge, UK.
Samih
S
Al-Hayek
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D003428:Cross Infection / Q000188:drug therapy* / Q000382:microbiology* / Q000652:urine; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology* / Q000652:urine; D005260:Female; D006801:Humans; D007709:Klebsiella / Q000187:drug effects* / Q000201:enzymology* / Q000302:isolation & purification; D007710:Klebsiella Infections / Q000188:drug therapy* / Q000382:microbiology*; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D013997:Time Factors; D014552:Urinary Tract Infections / Q000188:drug therapy* / Q000382:microbiology* / Q000652:urine; D001618:beta-Lactamases / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases
Drug resistance, microbial; Enterobacteriaceae; Fluoroquinolones; Nitrofurantoin; Urinary tract infections