Aerobic Grm1--Negative Pharyngeal Bacilli of Adult Ethiopians: Carriage Rates and Antibiograms

No Thumbnail Available



Journal Title

Journal ISSN

Volume Title


Addis Ababa University


The study was conducted to identify the types of Gramnegative pharyngeal bacilli and to determine their prevalence and antibiotic susceptibilities. One~thousand pharyngeal sHab specimens were processed: 300 from students, 303 from adult employees of Berhanena-· Selam Printing Press (BSP), 200 from hospital staff and 197 from patients. The isolates were iden'tified by standard biochemical tests. All isolates were tested for their sensitivities to 11 antibietics using the Kirby-Bauer technique. Forty-five (15%) students, 53 (17.5%) employees of BSP, 27(13.5%) hospital staff and 54(27.4%) patients were carriers of one or more Gram-negative bacilli (GNB). The pharyngeal carriage rates of GNB were similar among the various groups of healthy subjects (P>O.l) but they were lower than that of the patients (peO.Ol). The increase in prevalence vIaS not correlated to antimicrobial therapy, but seems to be associated vlith underlying disease and duration of hospitalization. There was no association between isolation rates of GNB and age or sex. Two hundred and nineteen strains of more than 18 species of Enterobacteriaceae or nonfermenting Gram-negative bacilli were isolated. Colony counts of these organisms were lower among healthy subjects than among pa'tients. Klebsiella Vias most frequently ir;olated (37%), followed by _~seudo2!'-0Tl_a.? (13.2%), -E-n-te-r-o-b-a"ct-e-r (12.8%) and -A=c-i-n--e-t-o-b-a_c ... -t-e--r (10%). Others were less frequently isolated. The frequency of isolation of Klebsiell~ was higher from students (49%) than from the other three study groups (32.5%; P<0.05). The J)ol}rhospital isolates were more sensi ti ve than the hospital isolates. Over 70% of the nonhospital isolat*s were sensitive to 8 of the 11 antibiotics but 55%, 32% and 30% were sensitive to cephalothin, carbenicillin and ampicillin respectively. Over 74% of the hospital isolates were sensitive to':only polymyxin, gen-tamicin and trimethoprim<'sulphamethoxazole. About 59-64% of the hospital isolates were sensitive to chloramphenicol, kanamycin and sulphadiazine, while to the other antibiotics only below 33% were sensitive. Only 4.4% of nonhospital isolates were sensitive to all. A few strains showed intermediate susceptibilities to antibiotics. Nultiple antibiotic resistance Has higher among the hospital isolate (88.5%) than among the nonhospital isolates (59.6%; P<O.OJ.). Eighty".three different resistance antibiograms of 1 to 10 antibiotics were detected. The resistance antibiograms were more varied among hospi<tal isolates than among nonhospital isolates. Double resistance antibiograms Here more frequent (28%) follO\<wd by triple resistance antibiograms (16%).