Prevalence and Characteristics of Listeria ivanovii Strains in Wild Rodents in China

Abstract

Listeria is ubiquitous in natural environments and can be isolated from animal hosts, including rodents. Listeria ivanovii and Listeria monocytogenes are the main pathogenic species that can cause serious listeriosis in animals and human. In this study, we investigated the prevalence of Listeria in wild rodents from six regions in China, and analyzed the molecular characteristics and antibiotics resistance of the L. ivanovii isolates. A total of 702 fecal samples of 25 different species of wild rodents were examined, and 75 were Listeria positive, including 26 L. ivanovii strains, 2 L. monocytogenes strains, and 47 Listeria innocus strains. The 26 L. ivanovii isolates (including 2 subspecies) were divided into 5 different sequence types by multilocus sequence typing with ST6 being the dominant type, and 5 different pulsotypes by pulsed-field gel electrophoresis. The results of antimicrobial susceptibility revealed that all L. ivanovii isolates were sensitive to rifampin, chloramphenicol, gentamicin, erythromycin, tetracycline, vancomycin, penicillin G, imipenem, trimethoprim-sulfamethoxazole, but some isolates (including ST1, ST7, and ST8) were resistant to clindamycin. The results suggest that the prevalence of L. ivanovii (3.7%, 26/702) in wild rodents was higher in some regions, and the genetic diversity of L. ivanovii isolates in the wild rodents is relatively low and most belong to one lineage. These wild rodents may act as the natural host for L. ivanovii and possibly transmit the pathogen between wild animals and humans.

Listeria monocytogenes at the human–wildlife interface: black bears (Ursus americanus) as potential vehicles for Listeria

“…Interestingly, L. seeligeri was not encountered among our bear isolates. Similarly, L. ivanovii accounted for many of the Listeria isolates from rodent surveys in China (Wang et al, 2017;Cao et al, 2019), but was not encountered in our study.…”

“…The prevalence of L. monocytogenes in our study (36%) was noticeably higher than in most other wildlife surveys, where prevalence ranged from 0.3% to 18% (Hayashidani et al , ; Lyautey et al , ; Wacheck et al , ; Nowakiewicz et al , ; Weindl et al , ; Wang et al ., ; Cao et al , ;). Only two wildlife studies, involving urban birds in Finland and France, respectively, yielded prevalence levels of 33–36% (Bouttefroy et al , ; Hellstrom et al , ), similar to what we found in the bears.…”

“…has rarely been found in other wildlife studies, where in fact the opposite was frequently observed, with L. monocytogenes tending to be noticeably less common than other Listeria spp. (Innoue et al, 1992;Quessy and Messier, 1992;Yoshida et al, 2000;Hellstr€ om et al, 2008;Wang et al, 2017;Cao , 2019). Only one study of rectal swabs from red fox, beech marten and raccoons in Poland found that, even though overall Listeria prevalence was low (approx.…”

Two Prevalent Listeria ivanovii subsp. ivanovii Clonal Strains With Different Virulence Exist in Wild Rodents and Pikas of China

“…Previous studies have noted that wild rodents and pikas in China carried various STs of L. ivanovii subsp. ivanovii, and the predominant sequence types were ST1 and ST2 (12,13). ST1 strains were collected from five species of wild rodents in Tibet and Yunnan province, which reveals the potential ability of ST1 clonal strains to spread cross species and regions (13).…”

“…A total of 116 L. ivanovii subsp. ivanovii strains were isolated from intestinal contents of wild rodents from 12 provinces in China during 2014-2016 (12,13). The strains belong to five sequence types (STs), and the predominant subtypes were ST1 (10/116, 8.62%) and ST2 (100/116, 86.21%).…”