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Background Escherichia coli is an important intestinal flora, of which pathogenic E. coli is capable of causing many enteric and extra-intestinal diseases. Antibiotics are essential for the treatment of bacterial infections caused by pathogenic E. coli; however, with the widespread use of antibiotics, drug resistance in E. coli has become particularly serious, posing a global threat to human, animal, and environmental health. While the drug resistance and pathogenicity of E. coli carried by tigers and leopards in captivity have been studied intensively in recent years, there is an extreme lack of information on E. coli in these top predators in the wild environment. Methods Whole genome sequencing data of 32 E. coli strains collected from the feces of wild Amur tiger (Panthera tigris altaica, n = 24) and North China leopard (Panthera pardus japonensis, n = 8) were analyzed in this article. The multi-locus sequence types, serotypes, virulence and resistance genotypes, plasmid replicon types, and core genomic SNPs phylogeny of these isolates were studied. Additionally, antimicrobial susceptibility testing (AST) was performed on these E. coli isolates. Results Among the E. coli isolates studied, 18 different sequence types were identified, with ST939 (21.9%), ST10 (15.6%), and ST3246 (9.4%) being the most prevalent. A total of 111 virulence genes were detected, averaging about 54 virulence genes per sample. They contribute to invasion, adherence, immune evasion, efflux pump, toxin, motility, stress adaption, and other virulence-related functions of E. coli. Sixty-eight AMR genes and point mutations were identified. Among the detected resistance genes, those belonging to the efflux pump family were the most abundant. Thirty-two E. coli isolates showed the highest rate of resistance to tetracycline (14/32; 43.8%), followed by imipenem (4/32; 12.5%), ciprofloxacin (3/32; 9.4%), doxycycline (2/32; 6.3%), and norfloxacin (1/32; 3.1%). Conclusions Our results suggest that E. coli isolates carried by wild Amur tigers and North China leopards have potential pathogenicity and drug resistance.

Background Cryptosporidiosis is an important zoonotic protozoan disease worldwide, but few studies on this disease have been performed in wild birds; thus, our knowledge of this disease is insufficient, even in zoo birds. Animals in zoos are possible zoonotic disease reservoirs, potentially resulting in zoonotic agent spillover to humans; accordingly, our understanding of such phenomena should be improved. Methods A total of 263 fresh fecal samples from 43 avian species were randomly collected from the Beijing Zoo and Harbin North Forest Zoo and screened for the prevalence of Cryptosporidium by 18S rRNA gene sequencing. Cryptosporidium species were distinguished based on the combined results of phylogenetic tree and genetic distance analyses conducted with the inclusion of seven avian Cryptosporidium species and 13 avian Cryptosporidium genotypes. The genetic diversity of Cryptosporidium parvum among different hosts, including humans, cattle, dogs, and birds, and the genetic diversity of avian C. parvum among avian hosts in China, Iraq and Brazil were determined based on C. parvum 18S rRNA haplotypes. Results The results of PCR targeting the 18S rRNA gene revealed that 1.9% (5/263) of the samples were Cryptosporidium-positive. Four of the five Cryptosporidium-positive samples originated from white cranes (Grus leucogeranus), and one originated from a flamingo (Phoenicopteridae). Avian C. parvum isolates, including the isolates examined in the present study, showed gene flow with other isolates from different types of hosts, including humans, cattle and dogs, indicating that zoo birds potentially pose zoonotic and pathogenic risks to humans and animals. Additionally, gene flow between avian C. parvum isolates from China and Brazil was detected. Conclusions To the best of our knowledge, our results demonstrate C. parvum infection in a flamingo (Phoenicopteridae) and white cranes (Grus leucogeranus) for the first time. The results of our study provide an important reference for understanding the host range, biological characteristics, and molecular epidemiology of C. parvum.

Cryptosporidium spp. is a protozoan having the potential to cause zoonosis in humans and animals. Despite the zoonotic importance of this protozoan parasite, limited data are available about its prevalence in zoo felids in North-Eastern China. Hence, the current study was designed to determine the occurrence and molecular characterization of Cryptosporidium spp. from the fecal samples of captive zoo felids. Fecal samples (N = 244) were collected from different felids from five different zoos of North-Eastern China. 18S rRNA gene was amplified from the genomic DNA using species specific primers in nested polymerase chain reaction (nPCR) and Cryptosporidium parvum and Cryptosporidium spp. was found. The overall prevalence of Cryptosporidium was 9.43% (23/244). The 18S rRNA gene similarity analysis showed that 6 Cryptosporidium isolates were Cryptosporidium parvum and the remaining 17 Cryptosporidium isolates were resembling to a Cryptosporidium spp., which is similar to Cryptosporidium NEV10. Phylogenetic tree was constructed based on 18S rRNA of Cryptosporidium spp. The similarity of Cryptosporidium parvum was with its other isolates in China, India, Iran, Iraq, Turkey, Czech Republic, Spain and USA while Cryptosporidium NEV10 alike had a close relationship with Turkish isolates. In conclusion, Cryptosporidium was prevailing in feline animals of China zoo and zoo officials are directed to consider their control policy as it can be a cause of zoonosis.