DETECTION OF EXTENDED SPECTRUM BETA LACTAMASES PRODUCING STRAINS OF ESCHERICHIA COLI AND KLEBSIELLA SPECIES FROM CLINICAL SPECIMENS AT UNIVERSITY OF MAIDUGURI TEACHING HOSPITAL, BORNO STATE, NIGERIA

Abstract

Resistance to a wide variety of common antimicrobials has made the proliferation of
extended spectrum beta lactamases (ESBLs) producing organisms a serious global health
concern that has complicated treatment strategies. These bacteria have spread rapidly and
have become a serious threat to human health worldwide. It is a great challenge for clinicians
to treat bacteria harbouring these enzymes. So, the present study was undertaken to detect and
characterize ESBLs in Escherichia coli and Klebsiella species by different methods, as well
as to identify the possible risk factors for their development.
Confirmed variants of Escherichia coli and Klebsiella species isolated from 439 patients that
were admitted in various units of UMTH Maiduguri were screened for ESBL using CLSI
breakpoints. Suspected ESBLs producers were subjected to confirmation using double disk
synergy method. All confirmed ESBL positive isolates also had their MIC determined using
Etest strips of cefotaxime and cefotaxime + amoxicillin-clavulanic acid. Detection of ESBL
genes was further done by multiplex PCR.
Out of the 439 isolates screened; the result shows 147 (33.5%) were ESBL producers but
only 121(23.6%) were confirmed by the double disk synergy method. The prevalence of
ESBL amongst the organisms were; 41/172 (23.8%) for Escherichia coli and 80/267 /(30.0%)
for Klebsiella species. Based on PCR analysis, the various percentage genotypes of the ESBL
producers were 44(36.4%) for SHV gene followed by 38(31.4%) for TEM gene and the
lowest of 33(27.3%) for CTX-M gene.
There was significant association between the acquisition of ESBLs and the following
parameters based on chi-square test; Level of education (X2=22.034, P=0.005), place of
residence (X2=7.619, P=0.022), ward of admission (X2 = 1.065, P = 0.000), number of days
on admission (X2 = 76.367, P = 0.000), past medical history (X2 = 45.512, P = 0.000), use of
medical device (X2 = 56.052, P = 0.000) and prior antibiotic usage (X2 = 54.564, P = 0.000).
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The predictors for acquisition of ESBL in the ward of admission, were admission in intensive
care unit (OR = 25.692, 95% CI = 7.125-100.5777) and admission in special care baby unit
(OR = 15.666, 95% CI = 3.724-49.125). Number of days on admission ≥ 25 days (OR =
36.07, 95% CI = 25.0-78.1) was also a predictor of ESBL acquisition. Past history of diabetes
mellitus (OR = 1.831, 95% CI = 1.685-17.351) was found to be the predictor in the category
of past medical history. However, for patients that used medical devices; the use of urethral
catheter (OR = 61.8, 95% CI = 32.6-78.2) was the predictor of ESBL acquisition. The use of
third generation cephalosporins in less than 4 weeks of admission (OR = 3.608, 95% CI =
3.326-33.146) was also significantly associated with ESBL acquisition.
ESBLs are present among species of Escherichia coli and Klebsiella species in Maiduguri,
Borno State and this calls for government and all stakeholders’ intervention in this area of
healthcare setting. Clinical laboratories should employ methods for rapid detection of these
ESBL isolates as recommended by CLSI. As these strains became resistant to available
antibiotics and they pass the gene to other clinical strains. Irrational use of third generation
cephalosporins must be discouraged so as to reduce the prevalence of ESBLs. Antibiotic
stewardship program should be established in all tertiary health centres of Nigeria.