Extended-spectrum β-lactamases (ESBLs) are enzymes that mediate resistance to newer β-lactam antibiotics, including extended-spectrum cephalosporins and monobactams. The production of ESBL is primarily plasmid mediated, and such plasmids often comprise the genes that encode resistance to other classes of antimicrobials, such as aminoglycosides and fluoroquinolones. Therefore, ESBL-producing microorganisms leave clinicians with limited therapeutic options in both human and veterinary medicine. Compared with human medicine, information regarding ESBL-producing microorganisms is limited in veterinary medicine. We screened for ESBL-producing Escherichia coli in dogs and cats admitted to National Taiwan University Veterinary Hospital, Taipei, from 2014 to 2017 and further analyzed the genotypes and phylogenetic traits of these ESBL producers. Double disk tests specified by the Clinical and Laboratory Standards Institute were performed on 283 E. coli isolates and revealed a total of 65 E. coli (54 from dogs and 11 from cats) with the ESBL phenotype (22.8%). bla CTX−M−1 group and bla CTX−M−2group were the most commonly identified ESBL gene groups. bla CTX−M−55 was the main ESBL gene within the bla CTX−M−1group , whereas the bla CTX−M−2group contained only bla CTX−M−124. The ESBL-producing E. coli were all resistant to ampicillin. The resistance rate to ceftiofur, doxycycline, enrofloxacin, and ciprofloxacin was 93.8, 73.8, 80, and 78.5%, respectively. Of the antibiotics tested, greater sensitivity to imipenem and gentamicin was noted. Multilocus sequence typing indicated that ST457, ST131, and ST648 were the most common sequence types. Our study identified eight ST131/O25b isolates, which is a global zoonotic clone of public health concern. The major ESBL genes Huang et al. ESBL-Producing Escherichia coli of these clones were bla CTX−M−174 and bla CTX−M−194. Because companion animals such as dogs and cats are in close contact with humans, the characterization of ESBL producers originating from them is crucial from the perspective of both public health and veterinary medicine.

Extended-spectrum [Formula: see text]-lactamase (ESBL)-producing microorganisms often cause severe infections; they have only limited therapeutic alternatives and have emerged in both human and veterinary medicine. Companion animals have prolonged contact with humans and could serve as a reservoir for ESBL strains. Information regarding ESBL producers in companion animals is rather limited compared to that regarding humans. Therefore, the objective of this study was to screen for ESBL producers in Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis in urine samples collected from dogs and cats in which urinary tract infection was suspected in a veterinary teaching hospital in Taipei, Taiwan. In addition, bla genes, multilocus sequence typing (MLST) analysis, and antibiotic susceptibility testing were performed on these ESBL producers. From December 2011 to March 2013, disc tests of cefotaxime and ceftazidime, with and without clavulanic acid, were performed on 60 E. coli, 22 [Formula: see text]. pneumoniae, and 18 P. mirabilis samples isolated from urine; 2 E. coli and 5 K. pneumoniae samples with the ESBL phenotype were identified. CTX-M-15 was the most frequently found bla gene. CTX-M-14, SHV-11, SHV-12, and SHV-28 were also identified. MLST analysis did not detect a predominant ST type in either E. coli or [Formula: see text]. pneumoniae; nonetheless, K. pneumoniae ST15 and ST11, which are zoonotic agents of public health concern, were detected in our study. All ESBL-producing bacteria exhibited a multidrug-resistant phenotype. The occurrence of ESBL-producing E. coli and K. pneumoniae in companion animals underscores the importance of ESBL screening and epidemiological study in veterinary hospitals.

An important Salmonella serovar for both human and animals Salmonella Typhimurium possesses 13 gene clusters that have the potential to produce fimbrial structure, among which the type 1 fimbriae with the binding specificity to mannose residue is the most commonly found type. Six structural genes and five regulatory genes comprise the fim gene cluster that is responsible for the production of type 1 fimbriae in S. Typhimurium. The fimY gene encodes a positive regulator for type 1 fimbrial expression since a deletion in fimY abolished the production of fimbriae. The N‐terminal portion of FimY contains amino acid residues that exhibit some similarity as those found in the proteins possessing the PilZ domain, which is engaged in cyclic di‐GMP binding. A fimY allele that had a change from arginine to alanine at position 7 (R7A) or 7 and 11 (R7/11A) generated by site‐directed mutagenesis in a 6RRERH11R motif near N‐terminal, when cloned in pACYC184 and transformed into a fimY‐deleted strain, decreased the expression of fimA and fimZ. The number of type 1 fimbriae in these two transformants was also less than those of the other transformants that contained different fimY alleles in pACYC184 when observed in electron microscopy. However, changing from arginine to alanine at position 11 (R11A) remained the same as the wild‐type fimY allele. It is likely that the arginine at the 7th position of FimY is critical for its maximal activating activity upon fimZ. Another motif 83DI85SLWIEK91G motif did not affect the function of FimY. Although FimY has the two aforementioned motifs, which contain some amino acids that are present within those of the PilZ domain proteins, secondary structure prediction analysis did not reveal that FimY has a conformation commonly observed in PilZ‐like proteins. Therefore, FimY and PilZ domain proteins are not homologs. Further investigation for a detailed analysis of FimY is thus warranted.

Extended-spectrum-β-lactamase (ESBL) and AmpC β-lactamase are two enzymes commonly found in Enterobacteriaceae that confer resistance to major antibiotics, such as third-generation cephalosporins that are widely prescribed for both human and animals. We screened for Escherichia coli producing ESBL and plasmid-mediated AmpC β-lactamase (pAmpC) from dogs and cats brought to National Taiwan University Veterinary Hospital, Taipei, Taiwan from 29 June 2020, to 31 December 2020. The genotypes and phylogenetic relatedness of these E. coli were also analyzed. Fifty samples of E. coli obtained from 249 bacterial isolates were included in this study. Among them, eight isolates had ESBL, seven had pAmpC, and one had both. Thirty-two percent (16/50) of E. coli isolates were resistant to third-generation cephalosporins. The detected ESBL genes included the blaCTX-M-1 and blaCTX-M-9 groups, and the blaCMY-2 group was the only gene type found in pAmpC. ESBL-producing E. coli belonged to the pathogenic phylogroup B2, and the sequence types (STs) were ST131 and ST1193. Three isolates were determined to be ST131-O25b, a highly virulent epidemic clone. The pAmpC-producing E. coli were distributed in multiple phylogroups, primarily the commensal phylogroup B1. The STs of the pAmpC-producing E. coli included ST155, ST315, ST617, ST457, ST767, ST372, and ST93; all of these have been reported in humans and animals. Imipenem was active against all the ESBL/pAmpC-producing E. coli; however, since in humans it is a last-resort antimicrobial, its use in companion animals should be restricted.