Salmonellosis detection and evidence of antibiotic resistance in an urban raccoon population in a highly populated area, Costa Rica

Abstract

Wild animals are involved in zoonotic disease transmission cycles. These are generally complex and poorly understood, especially among animals adapted to life in human ecosystems. Raccoons are reservoirs and effective carriers for infectious agents such as Salmonella throughout different environments and contribute to the transference of resistance genes. This study examined the presence of circulating Salmonella sp. in a population of raccoons in a tropical urban environment and evaluated resistance to antibiotics commonly used to treat salmonellosis. A total of 97 raccoons of different ages and sex were included in this study. 49% (38–60 CI) of the faecal samples were positive for Salmonella spp. The study identified 15 circulating serovars with the most prevalent being S. Hartford (7/15), S. Typhimurium (4/15) and S. Bovismorbificans (4/15). These serovars correspond to the serovars detected in humans with clinical symptoms in Costa Rica. 9.5% of the Salmonella strains recovered demonstrated ciprofloxacin resistance, and 7.1% showed resistance to nalidixic acid. This study provides evidence of multiple Salmonella serovars circulating in a population of urban raccoons in Costa Rica. Furthermore, the study confirms the existence of antimicrobial resistance to two antibiotics used to treat human salmonellosis. The findings emphasize the role of the raccoon as a reservoir of Salmonella in the Greater Metropolitan Area of Costa Rica (GAM) and stress the need for active monitoring of the presence and possible spread in antibiotic resistance due to this peri‐domestic carnivore.

Rural Raccoons (Procyon lotor) Not Likely to Be a Major Driver of Antimicrobial Resistant Human Salmonella Cases in Southern Ontario, Canada: A One Health Epidemiological Assessment Using Whole-Genome Sequence Data

“…Among the remaining non-human sources, which included both phenotypically non-resistant and resistant isolates, the prevalence of multidrug resistance (3+ classes) and the diversity of resistance genes identified were highest among livestock isolates, followed by environmental isolates, and, lastly, raccoons. Although raccoons on swine farms were frequently infected with Salmonella [29% prevalence, as previously demonstrated by Bondo et al (21)], antimicrobial resistance was uncommon (3.2%), and was comparable or lower than other studies of Salmonella in urban and suburban raccoons in Costa Rica and Japan [9-27%; (19,22)]. Antimicrobial resistance genes were generally highest in human (e.g., bla CMY−2 ) and livestock sources (e.g., tetB) compared with raccoon and environmental isolates, consistent with a lack of direct exposure of free-ranging wildlife to antimicrobials (other than in wildlife rehabilitation settings).…”

“…With the vast majority of zoonotic disease investigations of Salmonella in wildlife focused on wild avian species, there is comparatively little work examining terrestrial wild mammals such as raccoons (Procyon lotor). A number of cross-sectional surveys have determined that raccoons can be asymptomatic carriers of non-typhoidal Salmonella, with serovars that overlap with those commonly responsible for causing illness in humans (19)(20)(21)(22). Two studies which included genotypic assessments of Salmonella demonstrated the presence of identical pulsed-field gel electrophoresis (PFGE) patterns for certain human and raccoon isolates (23,24).…”

Community-Acquired Antimicrobial Resistant Enterobacteriaceae in Central America: A One Health Systematic Review

“…Intermediate resistance to streptomycin and to sulfonamides was detected in 50% of the isolates. In raccoons ( Procyon lotor ) from urban Costa Rica, Salmonella was isolated from 42 (49%) of 86 viable fecal samples and were tested for antibiotic susceptibility [ 40 ]. Isolates were resistant to two antimicrobials commonly used to treat salmonellosis in Costa Rica: ciprofloxacin (9.5%) and nalidixic acid (7.1%).…”

Using whole-genome sequence data to examine the epidemiology of antimicrobial resistance in Escherichia coli from wild meso-mammals and environmental sources on swine farms, conservation areas, and the Grand River watershed in southern Ontario, Canada

“…Much of the work examining the epidemiology of AMR in wildlife has been focused on wild birds [4,17,18]. However, there is mounting evidence that mammalian wildlife, such as raccoons (Procyon lotor), striped skunks (Mephitis mephitis), and Virginia opossums (Didelphis virginiana), can also harbour antimicrobial resistant bacteria and might therefore represent a potential source of resistant clones or AMR genes for humans and domestic animals [19][20][21][22][23][24][25]. With the decreasing cost of whole-genome sequencing, this technology is increasingly being used in wildlife research to simultaneously identify strains, resistance genes, plasmids, and other genetic markers, such as virulence genes, using a single laboratory processing method [26,27].…”