First Detection of Resistance Genes Encoding Extended Spectrum Beta-Lactamase Producing Escherichia coli at Lome, Togo

Abstract

Background: Extended Spectrum β-lactamases (ESBLs) are enzymes produced by some bacteria that inactivate oxyimino-cephalosporins, a class of β-lactam antibiotics family. They are mainly encoded by the β-lactamase gene families TEM, SHV and CTX-M. The Enterobacteriaceae expressing these genes, in particular Escherichia coli are widely expanded in the world with different prevalence rate from one region to another. The objective of this study, carried out from strains isolated at the National Institute of Hygiene (INH) in Togo, was to (i) detect and characterize the genes involving in the production of β-lactamase among E. coli strains and (ii) evaluate their prevalence. Methodology: From May 2013 to July 2015, 91 E. coli strains resistant to third generation cephalosporins (C3G) were collected from several specimens and analyzed for the detection of β-lactamase resistance genes, blaTEM, blaSHV and blaCTX-M by simplex and multiplex PCR. Results: The E. coli strains resistant at least to one third generation cephalosporin, were isolated from urine 58/91 (63.74%), vaginal samples 17/91 (17.68%), wound swabs 7/91 (7.69%), 4/91 semen samples (4.40%), urethral curettage CU 2/91 (2.20%), sputum 1/91 (1.1%), stool 1/91 (1.1%) and joint fluid 1/91 (1.1%). Resistance to third generation cephalosporins was associated with a resistance to quinolone (96.67%), trimethoprim/sulfamethoxazole (94.44%), gentamicin (75.82%) and chloramphenicol (59.09%). ESBL genes were present in all E. coli strains with the following proportions: TEM/CTX-M1 52/91 (57.14%), TEM/SHV/CTX-M1 19/91 (20.88%), CTX-M 18/91 (19.78%), TEM 1/91 (1.10%) and TEM/SHV 1/91 (1.10%). Conclusion: The presence of ESBL producing E. coli is a reality in Togo and their wide dissemination compromises the treatment of classical infections such as urinary tract infection, bacterial pneumonia, sepsis or meningitis. The acquisition of molecular data on bacterial resistance to antibiotics is necessary for better therapeutic management of these infections. This is a first determination of the β-lactamase genes in Togo.