BACKGROUND: Escherichia fergusonii is a common conditionally pathogenic bacterium that infects humans and animals. E. fergusonii has been reported to cause diarrhea, respiratory disease, and septicemia, but it is rarely reported to cause skin infections in animals. E. fergusonii has been isolated from the skin and muscular tissue of Chinese pangolin (Manis pentadactyla aurita). To date, there have been no reports of Chinese pangolins with clinical signs of skin diseases.
METHODS: This case report describes the clinical case of a subadult (bodyweight: 1.1 kg) female Chinese pangolin from wild rescue with pustules and subcutaneous suppurative infection due to E. fergusonii in the abdominal skin. Bacterial culture, Biochemical analysis, PCR and histopathology were utilized to identify the bacteria in the pustule puncture fluid and infected tissue. To the best of our knowledge, this is the first report of E. fergusonii-related pustules on a Chinese pangolin.
CONCLUSIONS: This case report presents the first observed skin infection in a Chinese pangolin. E. fergusonii infection should be considered as a possible differential diagnosis of pustules and subcutaneous suppurative skin conditions in Chinese pangolins, and we also provide several recommendations for the diagnosis and treatment of this disease.

We report the case of a 68-year-old man who experienced Escherichia fergusonii bacteremia after esophageal cancer surgery. The patient presented with complaints of abdominal pain persisting for 1 week. The patient was diagnosed with esophageal malignancy, which was confirmed by surgical exploration and pathological biopsy. The patient developed septic shock on postoperative day 12, and blood culture suggested the growth of E. fergusonii. After treatment with meropenem, the patient\'s clinical symptoms improved significantly, and the second culture was negative. In this paper, we discuss the characteristics, diagnosis, and treatment of E. fergusonii. E. fergusonii is rarely reported, and its pathogenesis, drug resistance, and potential effects have not been completely confirmed. Thus, this case report adds valuable knowledge to the literature on E. fergusonii.

BACKGROUND: Escherichia fergusonii is a rare opportunistic pathogen in humans and animals, especially with biofilm.
METHODS: In one case, E. fergusonii with biofilm was detected in the bile, and silver staining was used to prove it had biofilm. The clinical characteristics and drug susceptibility of eight cases of E. fergusonii retrieved from the literature were also summarized.
RESULTS: This is a case of E. fergusonii with biofilm, which has not been reported in China. The 8 cases retrieved from the literature did not specify whether they had biofilm, but we analyzed their clinical characteristics and drug susceptibility. All patients were treated with antimicrobial drugs. 8 cases showed sensitivity to piperacillin/tazobactam and imipenem in 6 cases (75%), but poor sensitivity to levofloxacin and ciprofloxacin.
CONCLUSIONS: The silver staining method proved biofilm in this case, which is the first case of E. fergusonii with biofilm in China.

This study aimed to identify tigecycline-resistant tet(X4)-bearing Escherichia fergusonii isolated from pigs in China with a complete genome sequence.
E. fergusonii was isolated by selective medium and screened from tigecycline-supplemented agar plates. The microbroth dilution method was used for antimicrobial susceptibility testing, and the minimal inhibitory concentration (MIC) results refer to the interpretation standard in the Clinical and Laboratory Standards Institute of America (CLSI). Whole-genome sequencing was performed on the Illumina HiSeq and Nanopore GridION platforms. The antimicrobial resistance (AMR) genes virulence genes and replicon types of plasmids were predicted by the CGE server.
E. fergusonii EF21QZZ116 was identified from 760 faecal and caecal content samples and was resistant to tigecycline, tetracycline, ampicillin, sulfisoxazole, trimethoprim-sulfamethoxazole, spectinomycin, and florfenicol. The AMR genes tet(X4), blaTEM-1B, and floR are located on the hybrid IncFIA-IncHI1A-IncHI1B plasmid pQZZ166-tetX-190K and are 190 391 bp in length. This hybrid plasmid has high homology with the plasmids of Escherichia coli, Enterobacter cloacae, Klebsiella, Citrobacter, and Salmonella based on comparison and analysis with the NCBI database. Notably, conjugative transfer and S1 nuclease pulsed-field gel electrophoresis (S1-PFGE) assays show that the plasmid can transfer horizontally.
To the best of our knowledge, this is the first report of E. fergusonii carrying the tet(X4) gene isolated from a pig; this report provides insight into the AMR characteristics of E. fergusonii and offers insight into public health.

A total of 1,400 samples of food animals (pigs, chickens, and ducks) were collected between July and September 2019 in China to uncover the prevalence of E. fergusonii and its potential role in the evolution of antimicrobial resistance (AMR). An isolation of E. fergusonii was performed and pulsed-field gel electrophoresis (PFGE) was used to uncover the genetic relationship. The AMR of E. fergusonii isolates was comprehensively characterized using broth microdilution-based antimicrobial susceptibility testing, S1-PFGE, southern hybridization, whole-genome sequencing, and in-depth bioinformatics analysis. As a result, a total of 133 E. fergusonii isolates were obtained. These isolates could be grouped into 41 PFGE subclades, suggesting a diverse genetic relationship. The resistance phenotypes of sulfafurazole (97.74%) and tetracycline (94.74%) were the most frequently found. Of the E. fergusonii isolates, 51.88% were extended spectrum beta-lactamase (ESBL)-positive. Forty-three different AMR genes were revealed based on 25 genome sequences harboring mcr-1. Briefly, aph(6)-Id, aph(3\'\')-Ib and tet(A) genes were the most frequently observed, with the highest rate being 76.00% (19/25). Three mcr-1-harboring plasmids were identified after Nanopore sequencing, including pTB31P1 (IncHI2-IncHI2A, 184,652 bp), pTB44P3 (IncI2, 62,882 bp), and pTB91P1 (IncHI2-IncHI2A, 255,882 bp). Additionally, 25 E. fergusonii isolates harboring mcr-1 were clustered together with other E. fergusonii isolates from different regions and sources available in GenBank, suggesting a possible random process of mcr-1 transmission in E. fergusonii. In conclusion, E. fergusonii is widespread in food animals in China and might be an important reservoir of AMR genes, especially mcr-1, and facilitate the evolution of AMR. IMPORTANCEE. fergusonii, a member of the genus Escherichia, has been reported to transmit via the food chain and cause diseases in humans. However, the prevalence of multidrug-resistant E. fergusonii, especially mcr-1-positive E. fergusonii isolates, has rarely been reported. Here, we collected 1,400 samples from food animals in three provinces of China and obtained 133 E. fergusonii isolates (9.5%). We found that the prevalence of E. fergusonii isolates was diverse, with high levels of antimicrobial resistance. Among them, 18.8% E. fergusonii isolates carried the colistin resistance gene mcr-1. Thus, E. fergusonii may facilitate the evolution of colistin resistance as a reservoir of mcr-1. As far as we know, the prevalence and AMR of E. fergusonii in the food animals in this study was first reported in China. These findings increase our understanding of the role of E. fergusonii in public health and the evolution of antibiotic resistance.