BIOCHEMICAL PROFILE, SEROTYPES, GENOTYPES AND RESISTANCE PHENOTYPES OF VIBRIO CHOLERAE O1 ISOLATED FROM CHAD, 2010-2020
Nadlaou Bessimbaye*, Bakarnga-Via Issakou,Tsouh Foukou Patrick Valere, Djimadoum Mbanga, Khadidja Gamougame, Nicolas Barro and Abdelsalam Tidjani
ABSTRACT
Chad experienced five cholera epidemics in 15 provinces out of 23 and 39 health districts out of 61 from 2010 to 2020. Four epidemic foci were identified based on the onset, the spread of epidemics and the surface-water hydrology viz. the Lake Chad basin, Chari-Logone basin, Mayo-Kébbi basin and the city of N'Djamena. Stools were collected into sterile vials containing alkaline peptone water. Vibrio cholerae O1 was isolated using TCBS and Muller-Hinton agar and identified by agglutination tests, API®20E and API®20NE galleries. Their identities were confirmed using Vitek2TM and PFGE automated systems and RT-PCR. Chad recorded 25827 cases of cholera and 802 deaths in five years, with a mortality rate of 3.10%. Vibrio cholerae O1, all of El Tor biotypes, were detected in 56% of stools of which and consist in 71.03% Ogawa and 29% Inaba serotypes. The susceptibility profiles of the strains to antibiotics varied from one antibiotic to another. Resistance rates of 100% were observed with trimethoprim-sulfamethoxazole and vibriostatic compound O / 129. The most active antibiotics are doxycycline (99.45%), tetracycline (99%), norfloxacin (78.14%) and ciprofloxacin (76%). As well, 71 out 72 isolated strains (98.61%) carriers of the virulence genes encoding for the synthesis of cholera toxin (ctxB and ctxA) as confirmed by molecular analyses. Overall, doxycycline, alternatively tetracycline, ciprofloxacin and norfloxacin should be endorse for the treatment of cholera in Chad.
Keywords: Vibrio cholerae O1, serotype, genotype, biochemical, Resistance phenotype, Chad.
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