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Extended-Spectrum ß-Lactamases in isolates of <i>Klebsiella</i> spp and <i>Escherichia coli</i> from Lagos, Nigeria

Ibukun Aibinu
Tolu Odugbemi
Brian J Mee


Objectives: To investigate the occurrence of Extended-Spectrum Beta-Lactamase (ESBL) enzymes in isolates of Klebsiella spp and E.coli from various health institutions in Lagos.

Methods: From December 2000 to October 2001, 356 isolates of Klebsiella spp (200) and Escherichia coli (156) were investigated for ESBL production. These isolates were obtained from the Microbiology laboratories of 7 hospitals in Lagos metropolis.

Results: Seventy four (20.8%) were found to be ESBL-producers using the double-disk test (DD test). Amongst the ESBL-producers, Klebsiella pneumoniae (60.8%) was the most represented followed by E.coli (31.1%). All strains positive to DD tests were confirmed for the carriage ESBL genes by polymerase Chain Reaction (PCR amplification). A total of 54 (73%) strains were positive for PCR, of which 12 (22.2%) were of the TEM-type, 26 (48.2%) of SHV-type and 16 (29.6%) of both types. About 27% of the ESBL-producers could not be amplified by PCR using TEM and SHV primers. Isoelectric focusing analysis showed the presence of 2 enzsymes with pI of 7.0 and 8.5 which were non-TEM and non-SHV enzymes in addition to enzymes with pl of 8.2, 7.6 and 5.8 which were of the TEM and SHV-type. A very low number, 10 (13.5%) of the ESBL-producers transferred ESBL resistance by conjugation experiment suggesting that ESBL-resistance in Lagos hospitals, may be generally chromosomal or carried by non-self transferable plasmids.

Conclusion: The production of Extended-Spectrum Beta-Lactamase enzymes by clinical isolates compromise the efficacy of beta-lactam antibiotics, particularly the extended-spectrum cephalosporins which are widely used in the treatment of serious gram-negative infections. There are now increasing clinical evidence that shows the importance of detecting strains producing this enzyme in our environment to prevent their spread.

Key Words:Extended-Spectrum Beta-Lactamase, Klebsiella spp, E. coli.

Nig. J. Health and Biomed. Sciences Vol.2(2) 2003: 53-60

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