Serotypes, virulence factors, antibiotic sensitivity, beta-lactamase activity and plasmid analysis of Salmonella from children with diarrhea in Tripoli (Libya).
A total of 21 Salmonella strains isolated in Libya (16 from children with diarrhea and 5 from healthy controls) were serotyped and studied for their cell invasive ability, production of cytotoxin, antibiotic susceptibility, beta-lactamase activity and plasmid profiles. Eight different serotypes of Salmonella were identified: 6 S. saintpaul, 4 S. wien (1 from control), 2 S. newport, 2 S. muenchen (1 from control), 2 S. typhimurium (1 from control), 2 S. hadar (1 from control), 2 S. reading (1 from control), 1 S. kottbus. Twenty (95%) were positive in the invasiveness assay using HeLa cells, and all (100%) were negative for cytotoxin production in HT29 cells. More than 40% were resistant to ampicillin, cefalexin, cefamandole, cefoperazone, chloramphenicol, gentamicin, mezlocillin and trimethoprimsulphamethoxazole and 100% were susceptible to the new quinolones. Most (67%) of the strains harbored plasmids and 43% produced beta-lactamase. A strong association was observed between the presence of more than one plasmid, beta-lactamase activity, and multiple-resistance to antimicrobial agents and serotypes S. saintpaul and S. wien. Curing experiments with acridine orange showed that 2 plasmids (33 and 1.4 megadaltons) might be responsible for the resistance to chloramphenicol and gentamicin. The present study demonstrated that multiple-resistant salmonellae are widespread in Libya and the resistance is mainly plasmid mediated.
el-Ghodban
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Department of Microbiology, Eötvös Loránd University, Pázmány Péter sétány 1/c, H-1117 Budapest, Hungary.
Ghenghesh
K S
KS
Márialigeti
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Abeid
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S
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002648:Child; D003967:Diarrhea / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D018432:Drug Resistance, Multiple; D006367:HeLa Cells; D006801:Humans; D008002:Libya / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D012475:Salmonella / Q000145:classification / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000472:pathogenicity; D012480:Salmonella Infections / Q000382:microbiology*; D012703:Serotyping; D014774:Virulence; D001618:beta-Lactamases / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases