Abstract:
Background: Resistance to third generation cephalosporins due to acquisition and expression of
extended spectrum β-lactamase (ESBL) enzymes among Gram-negative bacteria is on the increase.
Presence of ESBL producing organisms has been reported to significantly affect the course and
outcome of an infection. Therefore infections due to ESBL isolates continue to pose a challenge to
infection management worldwide. The aim of this study was to determine the existence and to
describe phenotypic and genotypic characteristics of ESBLs in an Intensive Care Unit (ICU) setting
in Tanzania.
Methods: Between October 2002 and April 2003, clinical information and samples were collected
from patients suspected to have nosocomial infections in an Intensive Care Unit of a tertiary
hospital in Tanzania. The isolates were identified, tested for antimicrobial susceptibility and
analysed for presence of ESBL genes.
Results: Thirty-nine Gram-negative bacteria were isolated from clinical samples of 39 patients.
These isolates included 13 Escherichia coli, 12 Enterobacter spp, 5 Pseudomonas spp, 4 Proteus spp, 2
Klebsiella. pneumoniae, 2 Citrobacter freundii and 1 Chryseomonas luteola. Eleven (28.2%) of these
isolates were ESBL producing. The ESBL genes characterised were SHV-12, SHV-28 and CTX-M-
15. The ESBL producing isolates were more resistant to gentamicin and ciprofloxacin than non-
ESBL producing isolates.
Conclusion: This study shows the presence of ESBL genes among Gram-negative bacteria in the
ICU setting in Tanzania. There is a need to institute strict hospital infection control policy and a
regular surveillance of resistance to antimicrobial agents.
