Extended-spectrum ß-lactamase- and AmpC ß-lactamase-producing Enterobacterales associated with urinary tract infections in the New Zealand community: a case-control study.

OBJECTIVES: To assess whether having a pet in the home is a risk factor for community-acquired urinary tract infections associated with extended-spectrum ß-lactamase (ESBL)- or AmpC ß-lactamase (ACBL)- producing Enterobacterales. METHODS: An unmatched case-control study was conducted between August 2015 and September 2017. Cases (n = 141) were people with community-acquired urinary tract infection (UTI) caused by ESBL- or ACBL-producing Enterobacterales. Controls (n = 525) were recruited from the community. A telephone questionnaire on pet ownership and other factors was administered, and associations were assessed using logistic regression. RESULTS: Pet ownership was not associated with ESBL- or ACBL-producing Enterobacterales-related human UTIs. A positive association was observed for recent antimicrobial treatment, travel to Asia in the previous year, and a doctor's visit in the last 6 months. Among isolates with an ESBL-/ACBL-producing phenotype, 126/134 (94%) were Escherichia coli, with sequence type 131 being the most common (47/126). CONCLUSIONS: Companion animals in the home were not found to be associated with ESBL- or ACBL-producing Enterobacterales-related community-acquired UTIs in New Zealand. Risk factors included overseas travel, recent antibiotic use, and doctor visits.

Genomic and phenotypic comparison of two Salmonella Typhimurium strains responsible for consecutive salmonellosis outbreaks in New Zealand.

Salmonella enterica serovar Typhimurium DT160 was the predominant cause of notified human salmonellosis cases in New Zealand from 2000 to 2010, before it was superseded by another S. Typhimurium strain, DT56 variant (DT56v). Whole genome sequencing and phenotypic testing were used to compare 109 DT160 isolates with eight DT56v isolates from New Zealand animal and human sources. Phylogenetic analysis provided evidence that DT160 and DT56v strains were distantly related with an estimated date of common ancestor between 1769 and 1821. The strains replicated at different rates but had similar antimicrobial susceptibility profiles. Both strains were resistant to the phage expressed from the chromosome of the other strain, which may have contributed to the emergence of DT56v. DT160 contained the pSLT virulence plasmid, and the sseJ and sseK2 genes that may have contributed to the higher reported prevalence compared to DT56v. A linear pBSSB1-family plasmid was also found in one of the DT56v isolates, but there was no evidence that this plasmid affected bacterial replication or antimicrobial susceptibility. One of the DT56v isolates was also sequenced using long-read technology and found to contain an uncommon chromosome arrangement for a Typhimurium isolate. This study demonstrates how comparative genomics and phenotypic testing can help identify strain-specific elements and factors that may have influenced the emergence and supersession of bacterial strains of public health importance.

Carriage of Extended-Spectrum-Beta-Lactamase- and AmpC Beta-Lactamase-Producing Escherichia coli Strains from Humans and Pets in the Same Households.

Extended-spectrum-beta-lactamase (ESBL)- or AmpC beta-lactamase (ACBL)-producing Escherichia coli bacteria are the most common cause of community-acquired multidrug-resistant urinary tract infections (UTIs) in New Zealand. The carriage of antimicrobial-resistant bacteria has been found in both people and pets from the same household; thus, the home environment may be a place where antimicrobial-resistant bacteria are shared between humans and pets. In this study, we sought to determine whether members (pets and people) of the households of human index cases with a UTI caused by an ESBL- or ACBL-producing E. coli strain also carried an ESBL- or ACBL-producing Enterobacteriaceae strain and, if so, whether it was a clonal match to the index case clinical strain. Index cases with a community-acquired UTI were recruited based on antimicrobial susceptibility testing of urine isolates. Fecal samples were collected from 18 non-index case people and 36 pets across 27 households. Eleven of the 27 households screened had non-index case household members (8/18 people and 5/36 animals) positive for ESBL- and/or ACBL-producing E. coli strains. Whole-genome sequence analysis of 125 E. coli isolates (including the clinical urine isolates) from these 11 households showed that within seven households, the same strain of ESBL-/ACBL-producing E. coli was cultured from both the index case and another person (5/11 households) or pet dog (2/11 households). These results suggest that transmission within the household may contribute to the community spread of ESBL- or ACBL-producing E. coliIMPORTANCEEnterobacteriaceae that produce extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases (ACBLs) are important pathogens and can cause community-acquired illnesses, such as urinary tract infections (UTIs). Fecal carriage of these resistant bacteria by companion animals may pose a risk for transmission to humans. Our work evaluated the sharing of ESBL- and ACBL-producing E. coli isolates between humans and companion animals. We found that in some households, dogs carried the same strain of ESBL-producing E. coli as the household member with a UTI. This suggests that transmission events between humans and animals (or vice versa) are likely occurring within the home environment and, therefore, the community as a whole. This is significant from a health perspective, when considering measures to minimize community transmission, and highlights that in order to manage community spread, we need to consider interventions at the household level.

Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae in Dairy Farm Environments: A New Zealand Perspective.

Antimicrobial resistance (AMR) is a global issue for both human and animal health. Infections caused by antimicrobial-resistant bacteria present treatment option challenges and are often associated with heightened severity of infection. Antimicrobial use (AMU) in human and animal health is a main driver for the development of antimicrobial-resistant bacteria. Increasing levels of AMU and the development and spread of AMR in food-producing animals, especially in poultry and swine production, has been identified as a food safety risk, but dairy production systems have been less studied. A number of farm management practices may impact on animal disease and as a result can influence the use of antimicrobials and subsequently AMR prevalence. However, this relationship is multifactorial and complex. Several AMR transmission pathways between dairy cattle, the environment, and humans have been proposed, including contact with manure-contaminated pastures, direct contact, or through the food chain from contaminated animal-derived products. The World Health Organization has defined a priority list for selected bacterial pathogens of concern to human health according to 10 criteria relating to health and AMR. This list includes human pathogens such as the extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E), which can be associated with dairy cattle, their environment, as well as animal-derived food products. ESBL-E represent a potential risk to human and animal health and an emerging food safety concern. This review addresses two areas; first, the current understanding of the role of dairy farming in the prevalence and spread of AMR is considered, highlighting research gaps using ESBL-E as an exemplar; and second, a New Zealand perspective is taken to examine how farm management practices may contribute to on-farm AMU and AMR in dairy cattle.