(1) Background: there has been a growing concern about pet-spread bacterial zoonosis in recent years. This study aimed to investigate the trend in drug-resistance of canine Escherichia coli isolates in northeast China between 2012–2021 and the differences in drug-resistance of E. coli of different origins in 2021. (2) Methods: E. coli were isolated from feces or anal swab samples from dogs and cats, and their antibiotic susceptibility profiles and phylogenetic grouping were identified. PCR was applied on the extended spectrum β-lactamase (ESBL) E. coli for antibiotic resistance genes. (3) Results: five hundred and fifty-four E. coli isolates were detected in 869 samples (63.75%). The multidrug resistance (MDR) rates of E. coli in pet dogs showed a decreasing trend, but working dogs showed the opposite trend. Resistance genes bla_CTX-M and bla_CTX-M+TEM were dominant among the ESBL producers (n = 219). The consistency between the resistance phenotypes and genes was high except for fluoroquinolone-resistant ESBL E. coli. All ESBL E. coli-carrying bla_NDM were isolated from working dogs, and one of the strains carried mcr-1 and bla_NDM-4. Phylogroup B2 was the dominant group in pet cats, and more than half of the isolates from companion cats were ESBL E. coli. (4) Conclusions: the measures taken to reduce resistance in China were beginning to bear fruit. Companion cats may be more susceptible to colonization by ESBL E. coli. The problem of resistant bacteria in working dogs and pet cats warrants concern.

Colistin is used as one of the last available choices of antibiotics for patients infected by carbapenem-resistant bacterial strains, but the unrestricted use of colistin aggravated the acquisition and dissemination of mobile colistin resistance ( mcr ) genes. So far, 10 mcr genes have been reported in four continents around the world.

(1) Background: Antibiotic resistance in bacteria is an urgent global threat to public health. Migratory birds can acquire antibiotic-resistant and pathogenic bacteria from the environment or through contact with each other and spread them over long distances. The objectives of this study were to explore the relationship between migratory birds and the transmission of drug-resistant pathogenic Escherichia coli. (2) Methods: Faeces and swab samples from migratory birds were collected for isolating E. coli on the Inner Mongolia Plateau of northern China from 2018 to 2023. The resistant phenotypes and spectra of isolates were determined using a BD Phoenix 100 System. Conjugation assays were performed on extended-spectrum β-lactamase (ESBL)-producing strains, and the genomes of multidrug-resistant (MDR) and ESBL-producing isolates were sequenced and analysed. (3) Results: Overall, 179 isolates were antibiotic-resistant, with 49.7% MDR and 14.0% ESBL. Plasmids were successfully transferred from 32% of ESBL-producing strains. Genome sequencing analysis of 91 MDR E. coli strains identified 57 acquired resistance genes of 13 classes, and extraintestinal pathogenic E. coli and avian pathogenic E. coli accounted for 26.4% and 9.9%, respectively. There were 52 serotypes and 54 sequence types (STs), including ST48 (4.4%), ST69 (4.4%), ST131 (2.2%) and ST10 (2.2%). The international high-risk clonal strains ST131 and ST10 primarily carried bla_CTX-M-27 and bla_TEM-176. (4) Conclusions: There is a high prevalence of multidrug-resistant virulent E. coli in migratory birds on the Inner Mongolian Plateau. This indicates a risk of intercontinental transmission from migratory birds to livestock and humans.

This study aimed to evaluate antimicrobial resistance, virulence, and the genetic diversity of Aeromonas isolated from migratory birds from Guangxi Province, Guangdong Province, Ningxia Hui Autonomous Region, Jiangxi Province, and Inner Mongolia in China. A total of 810 samples were collected, including fresh feces, cloacal swabs, and throat swabs. The collected samples were processed and subjected to bacteriological examination. The resistance to 21 antibiotics was evaluated. A phylogenetic tree was constructed using concatenated gltA-groL-gyrB-metG-PPSA-recA sequences. Eight putative virulence factors were identified by PCR and sequencing, and a biofilm formation assay was performed using a modified microtiter plate method. In total, 176 Aeromonas isolates were isolated including A. sobria, A. hydrophila, A. veronii, and A. caviae. All isolates showed variable resistance against all 16 tested antibiotic discs, and only one antibiotic had no reference standard. Six kinds of virulence gene markers were discovered, and the detection rates were 46.0% (hlyA), 76.1% (aerA), 52.3% (alt), 4.5% (ast), 54.0% (fla), and 64.2% (lip). These strains were able to form biofilms with distinct magnitudes; 102 were weakly adherent, 14 were moderately adherent, 60 were non-adherent, and none were strongly adherent. Our results suggest that migratory birds carry highly virulent and multidrug-resistant Aeromonas and spread them around the world through migration, which is a potential threat to public health.

Background: Wohlfahrtiimonas chitiniclastica is an emerging fly-borne zoonotic pathogen, which causes infections in immunocompromised patients and some animals. Herein, we reported a W. chitiniclastica BM-Y from a dead zebra in China.Methods: The complete genome sequencing of BM-Y showed that this isolate carried one chromosome and one novel type of bla_VEB–1-carrying plasmid. Detailed genetic dissection was applied to this plasmid to display the genetic environment of bla_VEB–1.Results: Three novel insertion sequence (IS) elements, namely ISWoch1, ISWoch2, and ISWoch3, were found in this plasmid. aadB, aacA1, and gcuG were located downstream of bla_VEB–1, composing a gene cassette array bla_VEB–1–aadB–aacA1–gcuG bracketed by an intact ISWoch1 and a truncated one, which was named the bla_VEB–1 region. The 5′-RACE experiments revealed that the transcription start site of the bla_VEB–1 region was located in the intact ISWoch1 and this IS provided a strong promoter for the bla_VEB–1 region.Conclusion: The spread of the bla_VEB–1-carrying plasmid might enhance the ability of W. chitiniclastica to survive under drug selection pressure and aggravate the difficulty in treating infections caused by bla_VEB–1-carrying W. chitiniclastica. To the best of our knowledge, this is the first report of the genetic characterization of a novel bla_VEB–1-carrying plasmid with new ISs from W. chitiniclastica.

Gut microbes thrive by utilising host energy and, in return, provide valuable benefits, akin to a symbiotic relationship. Here, metagenomic sequencing was performed to characterise and compare the community composition, diversity and antibiotic resistance of the gut microbiota of Relict gull (Larus relictus) and Anatidae species. Alpha diversity analysis revealed that the intestinal microbial richness of L. relictus was significantly lower than that of Anatidae, with distinct differences observed in microbial composition. Notably, the intestines of L. relictus harboured more pathogenic bacteria such as clostridium, which may contribute to the decline in their population and endangered status. A total of 117 strains of Escherichia coli were isolated, with 90.60% exhibiting full susceptibility to 21 antibiotics, while 25.3% exhibited significant biofilm formation. Comprehensive Antibiotic Resistance Database data indicated that glycopeptide resistance genes were the most prevalent type carried by migratory birds, alongside quinolone, tetracycline and lincosamide resistance genes. The abundance of resistance genes carried by migratory birds decreased over time. This metagenomic analysis provides valuable insights into the intestinal microbial composition of these wild bird species, offering important guidance for their conservation efforts, particularly for L. relictus, and contributing to our understanding of pathogen spread and antibiotic-resistant bacteria.