Aerobic gram-negative pharyngeal bacilli of adult Ethiopians: carrier rates and antibiograms.

One thousand pharyngeal swab specimens were processed for aerobic culture to determine the carriage rate of Gram-negative bacilli (GNB). The isolates were identified and their sensitivity determined to 11 antibacterial drugs following standard techniques. Similar pharyngeal carriage rates of GNB were found among the various groups of healthy subjects. Patients had higher colonization rates (27%) than healthy subjects (16%). The increase in prevalence of GNB seemed to be associated with underlying diseases and duration of hospitalization. Klebsiella (36%) was the most frequent genus amongst the 215 isolates of GNB followed by pseudomonas (13%), enterobacter (13%) and acinetobacter (10%). Others were less frequently isolated. Over 70% of all isolates were resistant to ampicillin (79%) and carbenicillin (72%); 55, 45 and 43% were resistant to cephalothin, tetracycline and streptomycin, respectively. The great majority of the strains were sensitive to the remaining six drugs. The hospital isolates were more resistant than the non-hospital isolates to most drugs tested. The hospital strains were also more often multiply resistant (89%) than the non-hospital strains (60%). Sixty-five different resistance antibiograms of 1-10 drugs were observed among 191 strains. More varied types of antibiograms were observed among hospital strains. The high frequency of multiple drug resistance of the isolates is an indication of the extensive use of antibacterial drugs, indicating the need for a policy for judicious use of drugs.