Quinolone resistance among Salmonella Kentucky and Typhimurium isolates in Tunisia: first report of Salmonella Typhimurium ST34 in Africa and qnrB19 in Tunisia

N. Al‐gallas (1, 2) , N. Khadraoui (1, 3) , H. Hotzel (4) , H. Tomaso (4) , H. El‐adawy (4, 5) , H. Neubauer (4) , K. Belghouthi (1, 4) , K. Ghedira (6, 7) , H. K. Gautam (8, 9) , B. Kumar (8, 9) , D. Laouini (10) , S. Zarrouk (11) , M. S. Abbassi (7) , Ridha B. Aissa (1)

1 Laboratoire de Contrôle des Eaux et Denrées Alimentaires, Institut Pasteur de Tunis
2 UHB - University of Hafr Al Batin [Saudi Arabia]
3 Centre de Biotechnologie de Borj Cédria (Hammam-Lif, Tunisie)
4 FLI - Friedrich-Loeffler-Institut
5 Kafrelsheikh University
6 LR11IPT06 - Laboratoire de Parasitologie Médicale, Biotechnologies et Biomolécules
7 UTM - Université de Tunis El Manar
8 IGIB - CSIR Institute of Genomics and Integrative Biology [New Delhi]
9 AcSIR - Academy of Scientific and Innovative Research [Ghaziabad, India]
10 LR11IPT02 - Laboratoire de Transmission, Contrôle et Immunobiologie des Infections - Laboratory of Transmission, Control and Immunobiology of Infection
11 PFT-IPT - Plateforme de technologie IPTOmics

Aims Characterization of quinolone-resistant Salmonella Kentucky and Typhimurium isolates in Tunisia from various sources, detection of some plasmid-mediated quinolone resistance genes and the genetic relatedness. Methods A total of 1404 isolates of S. Kentucky (n = 1059)/S. Typhimurium (n = 345) from various sources from all over Tunisia were tested for quinolone resistance by disk diffusion method. Minimum inhibitory concentrations of nalidixic acid, ciprofloxacin and ofloxacin were determined. Quinolone-resistant isolates were screened for plasmid-mediated quinolone-resistance genes (qnrA,qnrB,qnrS, aac(6′)-Ib-cr and qepA) by polymerase chain reaction (PCR). Mutations in the quinolone-resistance-determining regions of the gyrA and parC genes were detected by PCR and DNA sequencing. Pulsed-field gel electrophoresis and multilocus sequence typing were accomplished for isolates harbouring plasmid-mediated quinolone-resistance genes. Results According to our selection criteria (NAL = resistance phenotype; CIP = resistant with diameter 0, or intermediate), only 63 S. Kentucky/41 S. Typhimurium isolates were investigated: 49% (5/104) were multidrug resistant. Two S. Typhimurium isolates harboured qnrB19 with different PFGE profiles. A mutation was detected in the gyrA gene for each of these two isolates. MLST revealed the presence of ST313 and ST34, an endemic sequence type. Conclusion Our study highlights the presence of quinolone multidrug-resistant Salmonella in humans and animals in Tunisia. This is the first report of S. Typhimurium ST34 in Africa and qnrB19 in Tunisia. Significance and Impact of the Study This is the first report that describes not only the current epidemiological situation of the quinolone resistance in S. Kentucky and Typhimurium isolated from various sources and regions in Tunisia, but also, the genetic resistance determinants associated with phenotypic antibiotic resistance and the molecular mechanisms of their quinolone-resistance. Also, we provide the first report of S. Typhimurium ST34 in Africa, and the first report of qnrB19 in Salmonella in Tunisia.

Mots clés: DNA sequencing; pulsed-field gel electrophoresis; quinolone resistance; Salmonella; Tunisia

Domaines: Sciences du Vivant [q-bio]

N. Al‐gallas, N. Khadraoui, H. Hotzel, H. Tomaso, H. El‐adawy, et al.. Quinolone resistance among Salmonella Kentucky and Typhimurium isolates in Tunisia: first report of Salmonella Typhimurium ST34 in Africa and qnrB19 in Tunisia. Journal of Applied Microbiology, 2021, 130 (3), pp.807 - 818. ⟨10.1111/jam.14822⟩. ⟨pasteur-03559619⟩