Epidemiology of shigellosis in Lagos, Nigeria: trends in antimicrobial resistance.
Antimicrobial susceptibility of Shigella spp. and Escherichia coli, isolated from diarrhoeal patients in Lagos, was studied from March 1999 to February 2000. Four hundred fifty-nine isolates were identified as shigellae (62) and E. coli (397). Shigella flexneri, S. dysenteriae, S. boydii, and S. sonnei accounted, respectively, for 51.6%, 17.7%, 17.7%, and 13% of the total number of shigellae isolated. Eleven cases of shigellosis occurred in the age group of 0-9 years, 22 cases in the age group of 10-19 years, and 29 cases in the age group of > or = 20 years. Of the 397 E. coli isolates, 11 were enteropathogenic E. coli (EPEC), and 7 of these strains were isolated with shigellae from stools of patients aged 0-9 year(s) (71.4%) and 10-19 years (28.6%). Over 70% of the Shigella isolates were resistant to two or more drugs, including ampicillin and tetracycline. Twenty-one distinct multidrug resistance patterns were observed in these isolates. During 1990-2000, resistance to ampicillin increased from 70% to 90%, co-trimoxazole from 77% to 85%, chloramphenicol from 71% to 77%, streptomycin from 71% to 79%, and nalidixic acid from 0% to 11.3%. Resistance to tetracycline decreased from 89% to 79% but with MIC50 and MIC90 values outside the susceptible range. While resistance to ciprofloxacin and ofloxacin remained nil with MIC50 and MIC90 values of 0.008 and 0.0016 microgram/mL respectively. The results of this study revealed the endemicity of shigellosis with S. flexneri as the predominant serogroup in Lagos. Children and young adults were at a higher risk of severe shigellosis. The results also suggest that ampicillin, tetracycline, co-trimoxazole, and streptomycin should not be used as the first-line drugs in the treatment of shigellosis. Nalidixic acid should still be selectively used for treatment, while ciprofloxacin and ofloxacin can be ideal alternatives.
Iwalokun
B A
BA
Biochemistry Department, College of Medicine, University of Lagos, P.M.B. 12003, Lagos, Nigeria. bamwal@yahoo.com
Gbenle
G O
GO
Smith
S I
SI
Ogunledun
A
A
Akinsinde
K A
KA
Omonigbehin
E A
EA
D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004405:Dysentery, Bacillary / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology; D004926:Escherichia coli / Q000187:drug effects; D004927:Escherichia coli Infections / Q000150:complications / Q000453:epidemiology; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D009549:Nigeria / Q000453:epidemiology; D012760:Shigella / Q000187:drug effects* / Q000254:growth & development
D000900:Anti-Bacterial Agents