The were reported in this study. It

The
resistant levels of ESBL producers are a major threat to infection management
as this may have contributed to the antibiotic resistance reported in this
study.  ESBL producing organisms are
known to contain plasmids with genes that encode resistance to aminoglycosides,
quinolones and cotrimoxazole. This is exemplified in the resistance profile of K.pneumoniae (Table
4 & 5). The high prevalence of blaTEM  among the C.freundii
isolates might be responsible for their high resistance to the ?-lactams {
amoxixillin (80%), cefpodoxime (80%) and ceftazidime (60%)} as observed in Table 6. It has been reported previously that
resistance to oxyimino-cephalosporins (e.g. cefpodoxime, and ceftazidime), is
caused mainly by TEM-type of ESBL 14.  However, ESBL producing E.coli and C. freundii isolates were
susceptible to fluoroquinolones. This finding is in line with a similar study
done in south eastern Nigeria by Iroha et al. 32.  They advised limited use of any
cephalosporin antibiotics on an ESBL positive E.coli infection. Since E.coli
isolates showed high prevalence of resistance to various antibiotics,
strategies to control the increase in resistant E.coli and other uropathogens would
be important. The observed low resistance of E.coli (13.8%) and Salmonella spp (13.3%) to cefotaxime  and high susceptibility to ceftriaxione (>
80 %) might be due to the   low   prevalence of blaCTX-M gene in this study. This analogy can also
explain the high resistance profile of K.pneumoniae
(64.9%) to cefotaxamine as 5 of the 14 K.pneumoniae
isolates harboured blaCTX-M1
gene. Among the Gram negative
pathogens blaCTX-M genes
have been reported as a vital mechanism of resistance to cefotaxime and ceftriaxone 8. Our findings are in line with the reports of
Basu et al. 23
which showed that the blaCTX
genes were predominant in Klebsiella spp .
Similarly Kuldeep and Nitika, 20 stated that majority of ESBLs in E.coli are derived from the widespread
plasmid mediated broad-spectrum ?-lactamases TEM-1. Low levels of blaGES, blaVEB, and blaPER
were reported in this study. It has been stated that the most frequently
detected clinically important ESBLs belong to the TEM, SHV and CTX-M families
while GES, VEB and PER  are of lesser
prevalence  27,
34 . Although, the frequency of ESBL–producing isolates is increasing
worldwide, the rate of infection can only be minimized by regular surveillance
and monitoring in order to institute effective and credible treatment and
management of UTI.

MBLs
have been recognized as one of the most notable resistance determinants in
Enterobacteriaceae 35. SPM gene  was the most predominant MBL gene in our study . There was mixed expression of the MBL genes among our
isolates. Ten (10) of the 25 MBL Screen positive E.coli had co-expression of more than
one MBL gene: 3(blaIMP+blaSPM), 1(blaSPM+blaGIM), 3(blaSPM+blaSIM), 1(blaSPM+blaVIM+blaSIM), 2(blaIMP+blaSPM+blaGIM+blaSIM). There are increasing reports of
MBL producing Gram negative bacteria in south-eastern Nigeria.  Ejikeugwu et
al., 36 recently reported
high occurrence of MBL producing E. coli and  Klebsiella species from an abbatior.
Since the genes that code for MBL production in Gram negatives are
chromosomally – or plasmid mediated they can easily be transmitted through
mobile genetic elements among   bacterial
population in a community
37.  The discrepancy in the percentage of
phenotypic and genotypic ?-lactamase confirmed producers might be because of
co-expression of more than 1 ESBL, MBL and or AmpC genes in an organism.  Occurrence of multiple ESBL types and/or
ESBL-AmpC combinations within the same organism has previously been reported to
make phenotypic identification of the ?-lactamases difficult and not reliable 31.  It
might also be that the genes detected by PCR are not effectively expressed
phenotypically 38.

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We
confirmed low prevalence of Amp C and KPC genes among our uropathogens while none of the E.coli isolates was positive for NDM genes. The AmpC producer was also found to be
ESBLs negative. The low prevalence of
AmpC genes in our study is likely to be responsible for the observed high
susceptibility of E.coli (75%) and
intermediately susceptible of Salmonella to cefoxitin.   Conversely, a study in Chennai India
reported that 61.9% of the uropathogenic 
E. coli isolates expressed an
AmpC phenotype 31.

 

Conclusively,
the uropathogens were found resistant to various antimicrobial classes. The study showed high
prevalence of drug resistant genes among the entrobacterial uropathogens.
Majority of the entrobacterial  uropathogens
harbored more than one antibiotic resistant gene. Our  study has notably shown that  of all the ESBL genes, the most predominant
gene in E. coli and Citrobacter freundii was blaTEM, in Salmonella spp was a combination of blaTEM+SHV, in Klebsiella kneumoniae, blaCTX-M1 was predominant
among  enterobacterial uropathogens isolated from
patients of  Anambra State University
Teaching Hospital, Awka.  Limitations of
the study include that we didn’t record the patient’s demographics and history
of their antibiotic consumption.