Characteristics of the antibiotic resistance plasmid in Salmonella typhi isolated in Tunis in 1990.
A multiresistant Salmonella typhi (S typhi, strain 302) was isolated from a blood culture of a patient in the Infectious Diseases department of Rabta Hospital in Tunis. The following tests were carried out: antibiotic susceptibility testing by the agar diffusion method; determination of the minimum inhibitory concentration against four beta-lactam antibiotics (amoxicillin, ceftriaxone, ceftazidime, imipenem), chloramphenicol, gentamicin, and amikacin by the agar dilution method; conjugation with E coli K12 for study of transferability of resistance markers; and electrophoresis of plasmid DNA extracts on agarose gel. S typhi 302 was resistant to amoxicillin, streptomycin, tetracycline, chloramphenicol, and sulfamide-trimethoprim, and this resistance was transferable in toto with a frequency of 10(-4). The MICs of amoxicillin and chloramphenicol were, respectively, 1024 (due to the production of TEM-1 beta-lactamase) and 256 mg/l. These resistance markers were carried by a plasmid of about 40 kb, similar to the Salmonella wien plasmid. The easy acquisition of a multiresistance plasmid by S typhi suggests that epidemiological monitoring of this serovar should be carried out.
Ben Hassen
A
A
Laboratoire de Microbiologie, Hôpital Charles-Nicolle, Tunis, Tunisia.
Meddeb
M
M
Ben Chaabane
T
T
Zribi
M
M
Ben Redjeb
S
S
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004337:Drug Carriers; D004352:Drug Resistance, Microbial; D004587:Electrophoresis, Agar Gel; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D012485:Salmonella typhi / Q000187:drug effects*; D014416:Tunisia
D000900:Anti-Bacterial Agents; D004337:Drug Carriers