Community-associated emergence of CTX-M and TEM extended spectrum beta-lactamase (ESBL)-producing Escherichia coli in Belgium

Abstract number: 1134_01_22

Rodriguez-Villalobos H., Cuvelier S., Dom I., Frankard J., Malaviolle V., Deplano A., Nonhoff C., De Mendonça R., Byl B., Struelens M.J.

Objectives:  

Recent reports indicate that CTX-M-producing Enterobacteriaceae are emerging in Europe and threaten current treatment strategies. We study the molecular epidemiology of ESBL-producing E. coli (ESBL-EC) over the last 4 years in a University hospital in Brussels, Belgium.

Methods:  

In 2000–2003, 10,281 E. coli clinical isolates were tested by disk diffusion and screened for ESBL production by double-disk synergy test. ESBL were characterized by Iso-electric focusing, multiplex PCR for bla genes of the SHV, TEM and CTX-M family and DNA sequencing. ESBL-EC strains were tested for MIC of 12 antimicrobials by agar dilution, genotyped by pulsed-field gel electrophoresis (PFGE) and screened for class I and II integrase by PCR.

Results:  

The proportion of ESBL-EC increased from 21(0.92%) in 2000, 33 (1.25%) in 2001, 48 (1.85%) in 2002 to 64 (2.34%) in 2003 (p < 0.001). Strains were isolated from 79 male and 86 female with a mean age of 63 years (0–94). Cases were community-associated (i.e. <48 hours after admission) in 41%, of whom 11% had previous contact with our institution. ESBL-EC isolates harboured CTX-M+TEM (35%), TEM alone (44%), CTX-M alone (6%), CTX-M+SHV (2%) or other ESBL combination (10%). DNA sequencing revealed CTX-M1 or CTX-M2. Class I integrase was detected in 71% of strains. Isolates included screening isolates from rectal swabs (37%), clinical isolates from urinary tract (38%), respiratory tract (10%), blood (2%) or other sites (13%). Nosocomial isolates (59%) originated from all hospital wards. PFGE typing showed polyclonality with a majority of sporadic cases with unique genotypes and a few clusters of 2 to 6 patients sharing the same genotype without direct contact during hospital stay. ESBL-EC showed high frequency of co-resistance to ciprofloxacin (61%), cotrimoxazole (62%), gentamicin (37%) and tobramycin (55%). Only meropenem and amikacin remained active on >95% of these isolates. Strains harbouring CTX-M enzymes showed significantly higher MICs to ceftriaxone, cefepime, amikacin and tobramicin, compared to those with other enzymes.

Conclusion:  

Although not previously reported in Belgium, multiresistant CTX-M and/or TEM ESBL-EC were detected with increasing frequency at this tertiary care centre. ESBL-EC appeared present on admission in a third of cases and was typically associated with urinary tract infection in elderly patients. Further analysis of clinical presentation and risk factors for infections with ESBL-EC is needed.