Antimicrobial susceptibility profile of community acquired and nosocomial isolates of Escherichia coli from clinical blood culture specimens at a Nigerian university teaching hospital

Objective:To ascertain the antibiotic susceptibility patterns of Escherichia coli recovered from blood culture specimens in Calabar.Nigeria.Methods:The study was retrospective in nature and was carried out at University of Calabar Teaching Hospital(UCTH) Calabar.Data generated from blood culture specimens over a five year period(Feb.2004-Feb.2009) was compiled, relevant information such as age,sex,organism recovered and antibiotic susceptibility patterns were obtained from patients records.Samples were collected,transported,stored and processed using standard laboratory procedures.Data obtained was analysed using Epi Info 6 statistical software.Results:Escherichia coli was responsible for 15.3%(31/203) of the blood infections being the third most common microorganism encountered.The community acquired(CA) isolates of the organism were significantly less resistant(P<0.05),compared to the nosocomial(NC) isolates against ampicillin.cloxacillin,amoxicillin,tetracycline,co-trimoxazole.chloramphenicol and erythromycin.The sensitivity of both the NC and CA isolates of Escherichia coli to amikacin, augmentin,ofloxacin,ciprofloxacin,ceftazidime,cefuroxime,ceftriaxone and rifampicin was generally high(80-100%) with no significant difference(P>0.05).Majority(>95.0%) of the NC isolates of Escherichia coli were resistant to six of the antibiotics tested.Conclusions:Control mechanisms for hospital acquired infections should be stepped up so as lo limit the spread of the highly resistant bacterial strains.Also the sale and consumption of antibiotics by the public need to be regulated.