SXT-related integrating conjugative element and IncC plasmids in Vibrio cholerae O1 strains in Eastern Africa.
OBJECTIVE
The objective of this study was to investigate the extent of resistance patterns and associated mobile genetic elements in epidemic V. cholerae O1 El Tor strains isolated from Eastern Africa in the late 1990s.


METHODS
Self-transmissible genetic elements and associated clusters of genes encoding resistance were detected by conjugation experiments. Detection of SXT-related integrating conjugative elements (ICEs) and associated antibiotic resistance genes was performed by PCR to amplify the SXT element-integrase gene (int), right SXT element-chromosome junction (attP-prfC) and genes conferring resistance to chloramphenicol (floR), sulfamethoxazole (sulII), streptomycin (strA) and trimethoprim (dfrA1). Genomic relatedness was established by random amplified polymorphic DNA patterns.


RESULTS
Of 224 strains analysed, 200 isolates exhibited resistance to four or more antimicrobials. An IncC plasmid, encoding resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and trimethoprim, conferred multidrug resistance to 113 strains isolated from Somalia and Ethiopia, whereas an SXT-related ICE, encoding resistance to chloramphenicol, streptomycin, sulfamethoxazole and trimethoprim, conferred multidrug resistance to 74 strains isolated from Sudan, Kenya and Tanzania.


CONCLUSIONS
This study has shown the spread of SXT-related ICEs among V. cholerae O1 African isolates. It has also highlighted the role of two distinct genetic elements in conferring multiple resistance to the two distinct groups of V. cholerae O1 strains that, in the late 1990s, spread through Eastern Africa, a critical geographic region for the persistence and transmission of cholera to the entire continent.
Pugliese
N
N
Dipartimento di Genetica e Microbiologia, Università di Bari, Bari, Italy.
Maimone
F
F
Scrascia
M
M
Materu
S F
SF
Pazzani
Carlo
C
D000351:Africa, Eastern / Q000453:epidemiology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D016000:Cluster Analysis; D003227:Conjugation, Genetic; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D005838:Genotype; D006801:Humans; D020071:Interspersed Repetitive Sequences; D008969:Molecular Sequence Data; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D019105:Random Amplified Polymorphic DNA Technique; D017422:Sequence Analysis, DNA; D041241:Vibrio cholerae O1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial