Distribution of Fluoroquinolone-Resistant Escherichia coli in Parent Flocks Treated with Fluoroquinolones on Chick Stage and their Broiler Offspring

This study investigated the distribution of ofloxacin-resistant Escherichia coli (OFXR-EC) in broiler parent flocks (PS) treated with ofloxacin for 5 days from the time the chicks arrived at the poultry house, and their broiler offspring. OFXR-EC was detected in 22.95% of neonatal parent stock chicks (PSN) arriving at the poultry house. The detection rate of OFXR-EC in PS rearing was 72.49%, which was significantly higher than that detected in PSN. In addition, the detection rate of OFXR-EC was significantly lower in neonatal chicks of their offspring broilers (CSN) at 7.06% than that of PS, but was 24.62% in offspring broiler flocks (CS) at approximately 6 weeks of age. The OFXR-EC detection rate was significantly higher in CS than that in CSN, even though no therapeutic antimicrobials, including ofloxacin, were used from CSN to CS. In addition, the proportions of OFXR-ECs in E. coli isolated from samples in which OFXR-ECs were detected were 63.85% for PSN, 10.52% for PS, 62.00% for CSN, and 8.25% for CS. There was little difference in the composition ratio of OFXR-EC between PSN and CSN, or between PS and CS.

Antimicrobial-Resistant Enterobacterales Recovered from the Environment of Two Zoological Institutions Include Enterobacter cloacae Complex ST171 Producing KPC-4 Carbapenemase

Environmental surfaces can serve as reservoirs for pathogens and antimicrobial-resistant (AMR) bacteria in healthcare settings. Although active surveillance programs are used in veterinary and human healthcare, unconventional settings like zoological facilities are often overlooked, even though antimicrobials are used to maintain the health of their animal collections. Here, we used electrostatic cloths to conduct active environmental surveillance over a 2-year period at two zoological institutions to determine contamination prevalence of human-only and mixed animal-human touch environments with AMR bacteria. We recovered Enterobacterales isolates that expressed quinolone resistance, an AmpC-like phenotype, and an extended-spectrum β-lactamase phenotype from 144 (39%), 141 (38.2%), and 72 (19.5%) of the environmental samples, respectively. The zoological institutions, areas and exhibits within the zoological facility, and sampling surface type affected the odds of recovering AMR bacteria from the environment. Three carbapenemase-producing Enterobacter cloacae complex ST171 isolates recovered from one zoological facility harbored an IncH12 plasmid with a Tn4401b-KPC-4 transposon conferring multidrug resistance. One isolate maintained three tandem repeats of a Tn4401b-KPC-4 element on an IncHI2 plasmid, although this isolate was susceptible to the four carbapenem drugs tested. These three isolates and their IncH12 plasmids shared significant genomic similarity with two E. cloacae complex isolates recovered from canine patients at a regional veterinary hospital during year 2 of this study. Our results indicated that surface environments at zoological institutions can serve as reservoirs for AMR bacteria and their genes and have implications for animal and public health. IMPORTANCE Environmental surfaces can be a source of antimicrobial-resistant (AMR) bacteria that pose a risk to human and animal health. Zoological institutions are unique environments where exotic animals, staff, and visitors intermingle and antimicrobials are used to maintain animal health. However, zoological environments are often overlooked as reservoirs of AMR bacteria. Here, we show that zoological environments can serve as reservoirs of fluoroquinolone-resistant and extended-spectrum cephalosporin-resistant bacteria. In addition, we isolated three carbapenemase-producing Enterobacter cloacae complex strains carrying blaKPC-4, including one with a unique, tandem triplicate of the Tn4401b-KPC-4 element. Comparative whole genomics of these isolates with two E. cloacae complex isolates from patients at a regional veterinary hospital highlighted the possibility of local KPC-4 spread between animal environments. Our results suggest that environments at zoological institutions serve as reservoirs for AMR bacteria and pose a hypothetical One Health risk to the public, staff, and the wild animal populations in captivity.

A Clinical Trial Evaluating the Usefulness of Tailored Antimicrobial Prophylaxis Using Rectal-culture Screening Media Prior to Transrectal Prostate Biopsy: A Multicenter, Randomized Controlled Trial

The aim of this report is to introduce an on-going, multicenter, randomized controlled trial to evaluate whether tailored antimicrobial prophylaxis guided by rectal culture screening prevents acute bacterial prostatitis following transrectal prostate biopsy (TRPB). Patients will be randomized into an intervention or non-intervention group; tazobactam-piperacillin or levofloxacin will be prophylactically administered according to the results of rectal culture prior to TRPB in the intervention group whereas levofloxacin will be routinely given in the non-intervention group. The primary endpoint is the occurrence rate of acute bacterial prostatitis after TRPB. Recruitment begins in April, 2021 and the target total sample size is 5,100 participants.

Genomic Characterization of Fluoroquinolone-Resistant Thermophilic Campylobacter Strains Isolated from Layer Chicken Feces in Gangneung, South Korea by Whole-Genome Sequencing

Thermophilic Campylobacter species of poultry origin have been associated with up to 80% of human campylobacteriosis cases. Layer chickens have received less attention as possible reservoirs of Campylobacter species. Initially, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of two archived Campylobacter isolates (Campylobacter jejuni strain 200605 and Campylobacter coli strain 200606) from layer chickens to five antimicrobials (ciprofloxacin, nalidixic acid, erythromycin, tetracycline, and gentamicin) were determined using broth microdilution while the presence of selected antimicrobial resistance genes was performed by polymerase chain reaction (PCR) using specific primers. Whole-genome sequencing (WGS) was performed by the Illumina HiSeq X platform. The analysis involved antimicrobial resistance genes, virulome, multilocus sequence typing (MLST), and phylogeny. Both isolates were phenotypically resistant to ciprofloxacin (MIC: 32 vs. 32 µg/mL), nalidixic acid (MIC: 128 vs. 64 µg/mL), and tetracycline (MIC: 64 vs. 64 µg/mL), but sensitive to erythromycin (MIC: 1 vs. 2 µg/mL) and gentamicin (MIC: 0.25 vs. 1 µg/mL) for C. jejuni strain 200605 and C. coli strain 200606, respectively. WGS confirmed C257T mutation in the gyrA gene and the presence of cmeABC complex conferring resistance to FQs in both strains. Both strains also exhibited tet(O) genes associated with tetracycline resistance. Various virulence genes associated with motility, chemotaxis, and capsule formation were found in both isolates. However, the analysis of virulence genes showed that C. jejuni strain 200605 is more virulent than C. coli strain 200606. The MLST showed that C. jejuni strain 200605 belongs to sequence type ST-5229 while C. coli strain 200606 belongs to ST-5935, and both STs are less common. The phylogenetic analysis clustered C. jejuni strain 200605 along with other strains reported in Korea (CP028933 from chicken and CP014344 from human) while C. coli strain 200606 formed a separate cluster with C. coli (CP007181) from turkey. The WGS confirmed FQ-resistance in both strains and showed potential virulence of both strains. Further studies are recommended to understand the reasons behind the regional distribution (Korea, China, and Vietnam) of such rare STs.