Occurrence, Antimicrobial Resistance, and Virulence Profiles of <i>Salmonella</i> Serovars Isolated from Wild Reptiles in South Africa

Abstract

Reptiles are carriers of an array of microorganisms, including significant zoonotic bacteria of the genus <i>Salmonella</i>, which cause a disease referred to as salmonellosis that affects both animals and humans. This study investigated the occurrence of <i>Salmonella</i> serovars in wild reptiles at Timbavati Private Game Reserve in Limpopo Province, South Africa, and examined their virulence and antimicrobial resistance gene profiles. A total of 19 wild reptiles were sampled, which resulted in 30 presumptive <i>Salmonella</i> isolates. The isolates were identified using polymerase chain reaction (PCR) by amplifying the <i>invA</i> gene and were further confirmed by <i>16S</i> rRNA gene sequencing. <i>Salmonella</i> serovars were detected in chameleons (36.8%), lizards (31.6%), snakes (15.8%), and tortoises (15.8%). The use of 16S rRNA gene sequencing revealed that <i>Salmonella enterica</i> subsp. <i>enterica</i> serovar Salamae (30%), <i>S</i>. <i>enterica</i> subsp. <i>enterica</i> (16.7%), <i>S</i>. <i>enterica</i> subsp. <i>enterica</i> serovar Typhimurium (13.3%), and <i>S</i>. <i>enterica</i> subsp. <i>enterica</i> serovar Indiana (13.3%) were the four most common subspecies among the investigated 30 isolates. Detected virulence genes included <i>pag</i>N (100%), <i>hil</i>A (96.7%), <i>ssr</i>B (96.7%), <i>prg</i>H (86.7%), and <i>mar</i>T (86.7%). The isolates exhibited resistance to nalidixic acid (43.3%) and kanamycin (43.3%), followed by streptomycin (16.7%) and ciprofloxacin (3.3%). Antibiotic-resistant genes were detected as follows: <i>strA</i>, <i>strB</i>, <i>qnrA</i>, <i>qnrS</i>, <i>parC</i>, <i>aadA</i>, <i>aac</i>(<i>6</i>')-<i>Ib</i>, and <i>aac</i>(<i>6</i>')<i>-Ib-cr</i> at 33.3%, 6.7%, 16.7, 13.3%, 10%, 23.3%, 6.7%, and 10%, respectively. The findings highlight the necessity of educational initiatives aimed at reducing reptile-related infections. Effective antibiotic treatment appears promising for infection, given the minimal drug resistance observed in reptile <i>Salmonella</i> serovars in the current study.