Discussion Enterobacteriaceaefamily is the most reported cause ofUTI and are usually resistant to many antibiotics resulting in recurrent UTIs,particularly in the high risk population 16, 20. They present apublic health challenge and thus deserve an adequate attention.
For an in-depthunderstanding of the underlying resistance genotypes and/mechanisms this studycharacterized the enterobacterialuropathogens with respect to drug resistance and their?-lactamases production capacities. Antibiotic resistance is a key clinical and public healthproblem in treating infections caused by enterobacterial uropathogens. Emergenceof beta-lactamases producing Enterobacteriaceae reduces therapeutic optionsbecause the isolates often co-express resistance to other classes ofantibiotics. Ourpredominant isolates (E.
coli, Salmonella spp. and K. pneumoniae) showed variable resistance to most drugs tested . This is similar to the findings of Ekwealoret al. 1.The fluoroquinolones and gentamicin were highly active against E.coli isolates and thus can beprescribed for the emperic treatment of UTI caused by E coli.
Similarly, in Libya Abubaker et al., 5reported a very good susceptibility of uropathogenic E.coli to ciprofloxacin and a very lowresistance to gentamicin was equally reported by Elsayed et al 4 in Egypt. Inthe case of Salmonella spp, cefpodoximeshowed the highest activity against Salmonella spp and unlike the E.coli isolates, the salmonella spp. were resistant to theflouroquonolones.
Susceptibility test for K.pneumoniae showed that amoxicilin,cefpodoxine, cefotaxime,aztreonam and cefoxitin exhibited verypoor anti-pneumococcal activity whilethe flouroquinolones showed very good activity which is in agreement with the reports of Sikarwar &Batra 21 that a flouroquinolone, ciprofloxacin had a 90 %antibacterial activity against uropathogens. It was observed that K.pneumoniae isolates (Table 5) were more resistant to most of the antimicrobialagents tested than E.
coli andSalmonella isolates . Asimilar scenario of multidrug resistance (MDR) of uropathogenic Klebsiella spp. has been reported inLibya 5. It should be noted that all theisolates had poor susceptibility to co-trimoxazole and amoxicillin. This is inagreement with recently published work in Ethiopia where high level of resistance (>70%) were recorded fortrimethoprim/sulfamethoxazole and ampicillin by uropathogens 22. The observed low susceptibility might not beunconnected with the misuse of the agents astrimethoprim-sulfamethoxazole and ampicillin were the first choice of drug for the empirical treatment of UTI 22. Several researches have reported increasing prevalence of trimethoprim-sulfamethoxazole resistant-uropathogenicstrains and suggested fluoroquinolones as an alternative treatment choice for UTI23.
E.coli and Salmonella were very sensitive to aztreonamand ceftazidime. This observed low resistance rates ( to aztreonamand ceftazidime) may be due to less use of these drugs in treating bacterialinfections in Nigeria. A significant sensitivity to gentamicin was noted of E.coli and C. freundii (Table 6).
Tworelated studies in Abakilikii and Enugu both in south-eastern Nigeriaequally reported a remarkable susceptibility of uropthogesns to gentamicin 18, 24. This might be because gentamicin being aparenteral preparation might be used with much restriction. Improper antibiotic use: dose and duration ofadministration have been reported as predisposing factors for the emergence ofantibiotic resistant strains in a locality 4. Sixteen(27.6 %) of the screen positive E.
coliwas phenotypically confirmed to be ESBL producers. Similar rates (27.7%) ofESBLs have been reported from a neighboring southeastern state, Enugu byEjikeugwu et al 18 and 26.
1% insouth-western Nigeria 25. Lower prevalenceof ESBLs (6.7%) was detected phenotypically among uropathogenic E. coliin Northwestern Libya 5 . However, higherprevalence of ESBL – producing uropathogenic E.coli (38.9%) was reported in Nepal 11 and 40 % in Potohar region of Pakistan by Ali et al.
23. The rates of resistance of ESBL – producingbacteria to antibiotics have previously been reported to be geographicallydependent. This is due to the differences in antimicrobial usages and infectioncontrol practices used in these locations 26Onmolecular level, the prevalence of ESBL producing was: E.coli (60.34%), C.
freundii (100%), K.pneumoniae(64.28%) and Salmonella spp.
(46.66%). These high rates are of seriousconcern as the transmission of these enzymes is usually driven by insertion sequences, transposons, integrons,and plasmids which facilitate the spread of these genes among other species ofbacteria 27.
In addition, they often carrygenes that confer high levels of resistance to many other antibiotics and causehigh therapeutic failure among infected patients 16,28. The increasing prevalence of infections caused byantibiotic-resistant bacteria makes the empirical treatment of UTI difficultand the outcome unpredictable and is thus associated with higher cost oftherapy, increased risk of complications, morbidity and mortality 4,16. Manystudies reported that urine is an important source of ESBLs-producing E. coli 5,29.
A similar observation was noted by Iroha et al., 30 in a neighboringEnugu state where 81.8% of ESBL producingstrains of E.coli was isolated fromurine of Outpatients in a tertiary hospital.
ESBLs have been reported among 51–90% of Enterobacteriaceae in Asia.Similar to our findings, Padmavathy et al., 31 reported that the percentage of ESBL-producing E. coli was 66.
9 % in Chennai, India.