Massey Research Online - Browsing by Author "Midwinter AC"

Browsing by Author "Midwinter AC"

Now showing 1 - 19 of 19

Assessing antimicrobial resistance in pasture-based dairy farms: a 15-month surveillance study in New Zealand.
(American Society for Microbiology, 2024-10-23) Collis RM; Biggs PJ; Burgess SA; Midwinter AC; Liu J; Brightwell G; Cookson AL
Antimicrobial resistance is a global public and animal health concern. Antimicrobial resistance genes (ARGs) have been detected in dairy farm environments globally; however, few longitudinal studies have utilized shotgun metagenomics for ARG surveillance in pasture-based systems. This 15-month study aimed to undertake a baseline survey using shotgun metagenomics to assess the relative abundance and diversity of ARGs in two pasture-based dairy farm environments in New Zealand with different management practices. There was no statistically significant difference in overall ARG relative abundance between the two dairy farms (P = 0.321) during the study period. Compared with overseas data, the relative abundance of ARG copies per 16S rRNA gene in feces (0.08-0.17), effluent (0.03-0.37), soil (0.20-0.63), and bulk tank milk (0.0-0.12) samples was low. Models comparing the presence or absence of resistance classes found in >10% of all feces, effluent, and soil samples demonstrated no statistically significant associations (P > 0.05) with "season," and only multi-metal (P = 0.020) and tetracycline (P = 0.0003) resistance were significant at the "farm" level. Effluent samples harbored the most diverse ARGs, some with a recognized public health risk, whereas soil samples had the highest ARG relative abundance but without recognized health risks. This highlights the importance of considering the genomic context and risk of ARGs in metagenomic data sets. This study suggests that antimicrobial resistance on pasture-based dairy farms is low and provides essential baseline ARG surveillance data for such farming systems. IMPORTANCE: Antimicrobial resistance is a global threat to human and animal health. Despite the detection of antimicrobial resistance genes (ARGs) in dairy farm environments globally, longitudinal surveillance in pasture-based systems remains limited. This study assessed the relative abundance and diversity of ARGs in two New Zealand dairy farms with different management practices and provided important baseline ARG surveillance data on pasture-based dairy farms. The overall ARG relative abundance on these two farms was low, which provides further evidence for consumers of the safety of New Zealand's export products. Effluent samples harbored the most diverse range of ARGs, some of which were classified with a recognized risk to public health, whereas soil samples had the highest ARG relative abundance; however, the soil ARGs were not classified with a recognized public health risk. This emphasizes the need to consider genomic context and risk as well as ARG relative abundance in resistome studies.
Carriage of Extended-Spectrum-Beta-Lactamase- and AmpC Beta-Lactamase-Producing Escherichia coli Strains from Humans and Pets in the Same Households.
(American Society for Microbiology, 24/11/2020) Toombs-Ruane LJ; Benschop J; French NP; Biggs PJ; Midwinter AC; Marshall JC; Chan M; Drinković D; Fayaz A; Baker MG; Douwes J; Roberts MG; Burgess SA
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.
Corynebacterium megadyptis sp. nov. with two subspecies, Corynebacterium megadyptis subsp. megadyptis subsp. nov. and Corynebacterium megadyptis subsp. dunedinense subsp. nov. isolated from yellow-eyed penguins.
(Microbiology Society, 2023-02-07) Nouioui I; Saunderson SC; Midwinter AC; Young MJ; McInnes KM; Watts J; Sangal V
Novel Corynebacterium strains, 3BT and 7BT, were isolated from the oral cavities of young chicks of yellow-eyed penguins (hoiho), Megadyptes antipodes. A polyphasic taxonomic characterization of these strains revealed chemotaxonomic, biochemical and morphological features that are consistent with those of the genus Corynebacterium. The 16S rRNA gene sequence similarity values between the strains and their closest phylogenetic neighbour, Corynebacterium ciconiae CCUG 47525T were 99.07 %, values that are in line with their phylogenomic positions within the evolutionary radiation of the genus Corynebacterium. Digital DNA-DNA hybridization values and average nucleotide identities between the genome sequences of the two strains and related Corynebacterium species were well below the defined threshold values (70 and 95-96 %, respectively) for prokaryotic species delineation. The genome size of these strains varied between 2.45-2.46 Mb with G+C content 62.7-62.9 mol%. Strains 3BT and 7BT were Gram-stain positive bacilli that were able to grow in presence of 0-10 % (w/v) NaCl and at temperature ranging between 20-37 °C. The major fatty acids (>15 %) were C16 : 0 and C18 : 1 ω9c, and the mycolic acid profile included 32-36 carbon atoms. We propose that these strains represent a novel species, Corynebacterium megadyptis sp. nov. with 3BT (=DSM 111184T=NZRM 4755T) as the type strain. Phylogenomically, strains 3BT and 7BT belong to two lineages with subtle differences in MALDI-TOF spectra, chemotaxonomic profiles and phenotypic properties. The fatty acid profile of strain 3BT contains C18 : 0 as a predominant type (>15 %), which is a minor component in strain 7BT. Strain 7BT can oxidize N-acetyl-d-glucosamine, l-serine, α-hydroxy-butyric acid, l-malic acid, l-glutamic acid, bromo-succinic acid and l-lactic acid, characteristics not observed in strain 3BT. Therefore, we propose that these strains represent two subspecies, namely Corynebacterium megadyptis subsp. megadyptis subsp. nov. (type strain, 3BT=DSM 111184T=NZRM 4755T) and Corynebacterium megadyptis subsp. dunedinense subsp. nov. (type strain, 7BT=DSM 111183T=NZRM 4756T).
Detecting genes associated with antimicrobial resistance and pathogen virulence in three New Zealand rivers
(PeerJ, Inc, 2021-12-03) Davis M; Midwinter AC; Cosgrove R; Death RG; Oehlmann J
The emergence of clinically significant antimicrobial resistance (AMR) in bacteria is frequently attributed to the use of antimicrobials in humans and livestock and is often found concurrently with human and animal pathogens. However, the incidence and natural drivers of antimicrobial resistance and pathogenic virulence in the environment, including waterways and ground water, are poorly understood. Freshwater monitoring for microbial pollution relies on culturing bacterial species indicative of faecal pollution, but detection of genes linked to antimicrobial resistance and/or those linked to virulence is a potentially superior alternative. We collected water and sediment samples in the autumn and spring from three rivers in Canterbury, New Zealand; sites were above and below reaches draining intensive dairy farming. Samples were tested for loci associated with the AMR-related group 1 CTX-M enzyme production (bla CTX-M) and Shiga toxin producing Escherichia coli (STEC). The bla CTX-M locus was only detected during spring and was more prevalent downstream of intensive dairy farms. Loci associated with STEC were detected in both the autumn and spring, again predominantly downstream of intensive dairying. This cross-sectional study suggests that targeted testing of environmental DNA is a useful tool for monitoring waterways. Further studies are now needed to extend our observations across seasons and to examine the relationship between the presence of these genetic elements and the incidence of disease in humans.
Draft Genome Sequences of Seven Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from New Zealand Waterways.
(18/03/2021) Burgess SA; Francois M; Midwinter AC; Biggs PJ
Draft genomes of seven extended-spectrum β-lactamase (ESBL)-producing Escherichia coli strains recovered from New Zealand waterways are described. The mean genome size was 5.1 Mb, with 4,724 coding sequences. All genomes contained the ESBL gene bla CTX-M, and one carried a plasmid-mediated AmpC gene, bla CMY-2 A multidrug-resistant genotype was detected in three isolates.
Extended-spectrum β-lactamase- and AmpC β-lactamase-producing Enterobacterales associated with urinary tract infections in the New Zealand community: a case-control study
(Elsevier Ltd on behalf of International Society for Infectious Diseases, 2023-03) Toombs-Ruane LJ; Marshall JC; Benschop J; Drinković D; Midwinter AC; Biggs PJ; Grange Z; Baker MG; Douwes J; Roberts MG; French NP; Burgess SA
OBJECTIVES: To assess whether having a pet in the home is a risk factor for community-acquired urinary tract infections associated with extended-spectrum β-lactamase (ESBL)- or AmpC β-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.
Genome Sequences for Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Strains Isolated from Different Water Sources.
(17/06/2021) Gray HA; Biggs PJ; Midwinter AC; Burgess SA
Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae are considered a critical priority by the World Health Organization. Presented here are two genome sequences of Escherichia coli strains isolated from New Zealand freshwater. The genome sequences' mean size was 5.2 Mb, with a mean of 4,848 coding sequences. Both genomes carried the ESBL blaCTX-M gene.
Genomic adaptations of Campylobacter jejuni to long-term human colonization
(BioMed Central Ltd, 2021-12-10) Bloomfield SJ; Midwinter AC; Biggs PJ; French NP; Marshall JC; Hayman DTS; Carter PE; Mather AE; Fayaz A; Thornley C; Kelly DJ; Benschop J
BACKGROUND: Campylobacter is a genus of bacteria that has been isolated from the gastrointestinal tract of humans and animals, and the environments they inhabit around the world. Campylobacter adapt to new environments by changes in their gene content and expression, but little is known about how they adapt to long-term human colonization. In this study, the genomes of 31 isolates from a New Zealand patient and 22 isolates from a United Kingdom patient belonging to Campylobacter jejuni sequence type 45 (ST45) were compared with 209 ST45 genomes from other sources to identify the mechanisms by which Campylobacter adapts to long-term human colonization. In addition, the New Zealand patient had their microbiota investigated using 16S rRNA metabarcoding, and their level of inflammation and immunosuppression analyzed using biochemical tests, to determine how Campylobacter adapts to a changing gastrointestinal tract. RESULTS: There was some evidence that long-term colonization led to genome degradation, but more evidence that Campylobacter adapted through the accumulation of non-synonymous single nucleotide polymorphisms (SNPs) and frameshifts in genes involved in cell motility, signal transduction and the major outer membrane protein (MOMP). The New Zealand patient also displayed considerable variation in their microbiome, inflammation and immunosuppression over five months, and the Campylobacter collected from this patient could be divided into two subpopulations, the proportion of which correlated with the amount of gastrointestinal inflammation. CONCLUSIONS: This study demonstrates how genomics, phylogenetics, 16S rRNA metabarcoding and biochemical markers can provide insight into how Campylobacter adapts to changing environments within human hosts. This study also demonstrates that long-term human colonization selects for changes in Campylobacter genes involved in cell motility, signal transduction and the MOMP; and that genetically distinct subpopulations of Campylobacter evolve to adapt to the changing gastrointestinal environment.
Genomic Analysis of Salmonella enterica Serovar Typhimurium DT160 Associated with a 14-Year Outbreak, New Zealand, 1998-2012.
(2017-06) Bloomfield SJ; Benschop J; Biggs PJ; Marshall JC; Hayman DTS; Carter PE; Midwinter AC; Mather AE; French NP
During 1998-2012, an extended outbreak of Salmonella enterica serovar Typhimurium definitive type 160 (DT160) affected >3,000 humans and killed wild birds in New Zealand. However, the relationship between DT160 within these 2 host groups and the origin of the outbreak are unknown. Whole-genome sequencing was used to compare 109 Salmonella Typhimurium DT160 isolates from sources throughout New Zealand. We provide evidence that DT160 was introduced into New Zealand around 1997 and rapidly propagated throughout the country, becoming more genetically diverse over time. The genetic heterogeneity was evenly distributed across multiple predicted functional protein groups, and we found no evidence of host group differentiation between isolates collected from human, poultry, bovid, and wild bird sources, indicating ongoing transmission between these host groups. Our findings demonstrate how a comparative genomic approach can be used to gain insight into outbreaks, disease transmission, and the evolution of a multihost pathogen after a probable point-source introduction.
Molecular epidemiology of C. coli isolated from different sources in New Zealand between 2005 and 2014
(2/11/2015) Nohra A; Grinberg A; French N; Midwinter AC; Collins-Emerson J
© 2016, American Society for Microbiology. Campylobacteriosis is one of the most important foodborne diseases worldwide and a significant health burden in New Zealand. Campylobacter jejuni is the predominant species worldwide, accounting for approximately 90% of human cases, followed by Campylobacter coli. Most studies in New Zealand have focused on C. jejuni; hence, the impact of C. coli strains on human health is not well understood. The aim of this study was t o genotype C. coli isolates collected in the Manawatu region of New Zealand from clinical cases, fresh poultry meat, ruminant feces, and environmental water sources, between 2005 and 2014, to study their population structure and estimate the contribution of each source to the burden of human disease. Campylobacter isolates were identified by PCR and typed by multilocus sequence typing. C. coli accounted for 2.9% (n = 47/1,601) of Campylobacter isolates from human clinical cases, 9.6% (n = 108/1,123) from poultry, 13.4% (n = 49/364) from ruminants, and 6.4% (n = 11/171) from water. Molecular subtyping revealed 27 different sequence types (STs), of which 18 belonged to clonal complex ST-828. ST-1581 was the most prevalent C. coli sequence type isolated from both human cases (n = 12/47) and poultry (n = 44/110). When classified using cladistics, all sequence types belonged to clade 1 except ST-7774, which belonged to clade 2. ST-854, ST- 1590, and ST-4009 were isolated only from human cases and fresh poultry, while ST-3232 was isolated only from human cases and ruminant sources. Modeling indicated ruminants and poultry as the main sources of C. coli human infection. Importance: We performed a molecular epidemiological study of Campylobacter coli infection in New Zealand, one of few such studies globally. This study analyzed the population genetic structure of the bacterium and included a probabilistic source attribution model covering different animal and water sources. The results are discussed in a global context.
Nitrate enrichment does not affect enteropathogenic Escherichia coli in aquatic microcosms but may affect other strains present in aquatic habitats
(PeerJ, Inc, 2022-09-27) Davis MT; Canning AD; Midwinter AC; Death RG; Oehlmann J
Eutrophication of the planet's aquatic systems is increasing at an unprecedented rate. In freshwater systems, nitrate-one of the nutrients responsible for eutrophication-is linked to biodiversity losses and ecosystem degradation. One of the main sources of freshwater nitrate pollution in New Zealand is agriculture. New Zealand's pastoral farming system relies heavily on the application of chemical fertilisers. These fertilisers in combination with animal urine, also high in nitrogen, result in high rates of nitrogen leaching into adjacent aquatic systems. In addition to nitrogen, livestock waste commonly carries human and animal enteropathogenic bacteria, many of which can survive in freshwater environments. Two strains of enteropathogenic bacteria found in New Zealand cattle, are K99 and Shiga-toxin producing Escherichia coli (STEC). To better understand the effects of ambient nitrate concentrations in the water column on environmental enteropathogenic bacteria survival, a microcosm experiment with three nitrate-nitrogen concentrations (0, 1, and 3 mg NO3-N /L), two enteropathogenic bacterial strains (STEC O26-human, and K99-animal), and two water types (sterile and containing natural microbiota) was run. Both STEC O26 and K99 reached 500 CFU/10 ml in both water types at all three nitrate concentrations within 24 hours and remained at those levels for the full 91 days of the experiment. Although enteropathogenic strains showed no response to water column nitrate concentrations, the survival of background Escherichia coli, imported as part of the in-stream microbiota did, surviving longer in 1 and 3 mg NO3-N/Lconcentrations (P < 0.001). While further work is needed to fully understand how nitrate enrichment and in-stream microbiota may affect the viability of human and animal pathogens in freshwater systems, it is clear that these two New Zealand strains of STEC O26 and K99 can persist in river water for extended periods alongside some natural microbiota.
One dog's waste is another dog's wealth: A pilot study of fecal microbiota transplantation in dogs with acute hemorrhagic diarrhea syndrome
(PLOS, 2021-04-19) Gal A; Barko PC; Biggs PJ; Gedye KR; Midwinter AC; Williams DA; Burchell RK; Pazzi P; Carbonero F
Canine acute hemorrhagic diarrhea syndrome (AHDS) has been associated in some studies with Clostridioides perfringens overgrowth and toxin-mediated necrosis of the intestinal mucosa. We aimed to determine the effect of a single fecal microbiota transplantation (FMT) on clinical scores and fecal microbiomes of 1 and 7 dogs with AHDS from New Zealand and South Africa. We hypothesized that FMT would improve AHDS clinical scores and increase microbiota alpha-diversity and short-chain fatty acid (SCFA)-producing microbial communities' abundances in dogs with AHDS after FMT. We sequenced the V3-V4 region of the 16S-rRNA gene in the feces of AHDS FMT-recipients and sham-treated control dogs, and their healthy donors at admission, discharge, and 30 days post-discharge. There were no significant differences in median AHDS clinical scores between FMT-recipients and sham-treated controls at admission or discharge (P = 0.22, P = 0.41). At admission, the Shannon diversity index (SDI) was lower in AHDS dogs than healthy donors (P = 0.002). The SDI did not change from admission to 30 days in sham-treated dogs yet increased in FMT-recipients from admission to discharge (P = 0.04) to levels not different than donors (P = 0.33) but significantly higher than sham-treated controls (P = 0.002). At 30 days, the SDI did not differ between FMT recipients, sham-treated controls, and donors (P = 0.88). Principal coordinate analysis of the Bray-Curtis index separated post-FMT and donor dogs from pre-FMT and sham-treated dogs (P = 0.009) because of increased SCFA-producing genera's abundances after FMT. A single co-abundance subnetwork contained many of the same OTUs found to be differentially abundant in FMT-recipients, and the abundance of this module was increased in FMT-recipients at discharge and 30 days, compared to sham-treated controls. We conclude in this small pilot study FMT did not have any clinical benefit. A single FMT procedure has the potential to increase bacterial communities of SCFA-producing genera important for intestinal health up to 30 days post-FMT.
Phylogenomic Characterization of a Novel Corynebacterium Species Associated with Fatal Diphtheritic Stomatitis in Endangered Yellow-Eyed Penguins
(American Society for Microbiology, 2021-06-08) Saunderson SC; Nouioui I; Midwinter AC; Wilkinson DA; Young MJ; McInnes KM; Watts J; Sangal V; Segata N
Yellow-eyed penguins, Megadyptes antipodes, are an endangered species that are endemic to New Zealand. Outbreaks of diphtheritic stomatitis have caused significant mortality for this species, especially among young chicks. In this study, we isolated 16 Corynebacterium sp. isolates from the oral cavities of 2- to 14-day-old chicks at a range of infection stages and sequenced the genomes to understand their virulence mechanisms. Phylogenomic and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) characterization indicate that these strains belong to a novel Corynebacterium species. A simple multiplex PCR-based diagnostic assay has been developed to identify these strains rapidly and reliably. Similar to other corynebacteria, genomic islands and prophages introduced significant diversity among these strains that has potentially led to minor functional variations between the two lineages. Despite the presence of multiple corynebacterial virulence genes and a spaDEF-type pilus gene cluster among these strains, the survival rate was much higher in Galleria mellonella larvae than in those inoculated with Corynebacterium ulcerans NZRM 818 and Corynebacterium pseudotuberculosis NZRM 3004. Therefore, these strains are opportunistic pathogens causing high mortality among young penguin chicks due to a less-developed immune system. IMPORTANCE Yellow-eyed penguins, Megadyptes antipodes, are endangered species with a sharp decline in the numbers of breeding pairs over the last 2 decades. Diphtheritic stomatitis, characterized by a thick fibrinopurulent exudate in the oral cavities and symptoms, including inanition and significant weight loss, is responsible for significant mortality among the young chicks. These chicks are treated with antibiotics, amoxicillin-clavulanic acid or enrofloxacin, but do not always recover from the infection. The pathogen causing these infections and the mechanism of pathogenesis are unclear. This study has identified a novel Corynebacterium species to be associated with diphtheritic stomatitis in yellow-eyed penguins with potential virulence genes that are likely involved in pathogenesis. Importantly, a gene encoding an exotoxin, phospholipase D, is present among these strains. The inactivated form of this enzyme could potentially be used as an effective vaccine to protect these penguins from infection.
Population Structure and Antimicrobial Resistance in Campylobacter jejuni and C. coli Isolated from Humans with Diarrhea and from Poultry, East Africa.
(Centers for Disease Control and Prevention, 2024-10) French NP; Thomas KM; Amani NB; Benschop J; Bigogo GM; Cleaveland S; Fayaz A; Hugho EA; Karimuribo ED; Kasagama E; Maganga R; Melubo ML; Midwinter AC; Mmbaga BT; Mosha VV; Mshana FI; Munyua P; Ochieng JB; Rogers L; Sindiyo E; Swai ES; Verani JR; Widdowson M-A; Wilkinson DA; Kazwala RR; Crump JA; Zadoks RN
Campylobacteriosis and antimicrobial resistance (AMR) are global public health concerns. Africa is estimated to have the world's highest incidence of campylobacteriosis and a relatively high prevalence of AMR in Campylobacter spp. from humans and animals. Few studies have compared Campylobacter spp. isolated from humans and poultry in Africa using whole-genome sequencing and antimicrobial susceptibility testing. We explored the population structure and AMR of 178 Campylobacter isolates from East Africa, 81 from patients with diarrhea in Kenya and 97 from 56 poultry samples in Tanzania, collected during 2006-2017. Sequence type diversity was high in both poultry and human isolates, with some sequence types in common. The estimated prevalence of multidrug resistance, defined as resistance to >3 antimicrobial classes, was higher in poultry isolates (40.9%, 95% credible interval 23.6%-59.4%) than in human isolates (2.5%, 95% credible interval 0.3%-6.8%), underlining the importance of antimicrobial stewardship in livestock systems.
Prevalence and distribution of extended-spectrum β-lactamase and AmpC-producing Escherichia coli in two New Zealand dairy farm environments.
(2022) Collis RM; Biggs PJ; Burgess SA; Midwinter AC; Brightwell G; Cookson AL
Antimicrobial resistance (AMR) is a global threat to human and animal health, with the misuse and overuse of antimicrobials being suggested as the main driver of resistance. In a global context, New Zealand (NZ) is a relatively low user of antimicrobials in animal production. However, the role antimicrobial usage on pasture-based dairy farms, such as those in NZ, plays in driving the spread of AMR within the dairy farm environment remains equivocal. Culture-based methods were used to determine the prevalence and distribution of extended-spectrum β-lactamase (ESBL)- and AmpC-producing Escherichia coli from farm environmental samples collected over a 15-month period from two NZ dairy farms with contrasting management practices. Whole genome sequencing was utilised to understand the genomic epidemiology and antimicrobial resistance gene repertoire of a subset of third-generation cephalosporin resistant E. coli isolated in this study. There was a low sample level prevalence of ESBL-producing E. coli (faeces 1.7%; farm dairy effluent, 6.7% from Dairy 4 and none from Dairy 1) but AmpC-producing E. coli were more frequently isolated across both farms (faeces 3.3% and 8.3%; farm dairy effluent 38.4%, 6.7% from Dairy 1 and Dairy 4, respectively). ESBL- and AmpC-producing E. coli were isolated from faeces and farm dairy effluent in spring and summer, during months with varying levels of antimicrobial use, but no ESBL- or AmpC-producing E. coli were isolated from bulk tank milk or soil from recently grazed paddocks. Hybrid assemblies using short- and long-read sequence data from a subset of ESBL- and AmpC-producing E. coli enabled the assembly and annotation of nine plasmids from six E. coli, including one plasmid co-harbouring 12 antimicrobial resistance genes. ESBL-producing E. coli were infrequently identified from faeces and farm dairy effluent on the two NZ dairy farms, suggesting they are present at a low prevalence on these farms. Plasmids harbouring several antimicrobial resistance genes were identified, and bacteria carrying such plasmids are a concern for both animal and public health. AMR is a burden for human, animal and environmental health and requires a holistic "One Health" approach to address.
The Genetic Relatedness and Antimicrobial Resistance Patterns of Mastitis-Causing Staphylococcus aureus Strains Isolated from New Zealand Dairy Cattle
(MDPI (Basel, Switzerland), 2021-11-22) Greening SS; Zhang J; Midwinter AC; Wilkinson DA; McDougall S; Gates MC; French NP; Butaye P
Staphylococcus aureus is one of the leading causes of bovine mastitis worldwide and is a common indication for use of antimicrobials on dairy farms. This study aims to investigate the association between on-farm antimicrobial usage and the antimicrobial resistance (AMR) profiles of mastitis-causing S. aureus. Whole-genome sequencing was performed on 57 S. aureus isolates derived from cows with either clinical or subclinical mastitis from 17 dairy herds in New Zealand. The genetic relatedness between isolates was examined using the core single nucleotide polymorphism alignment whilst AMR and virulence genes were identified in-silico. The association between gene presence-absence and sequence type (ST), antimicrobial susceptibility and dry cow therapy treatment was investigated using Scoary. Altogether, eight STs were identified with 61.4% (35/57) belonging to ST-1. Furthermore, 14 AMR-associated genes and 76 virulence-associated genes were identified, with little genetic diversity between isolates belonging to the same ST. Several genes including merR1 which is thought to play a role in ciprofloxacin-resistance were found to be significantly overrepresented in isolates sampled from herds using ampicillin/cloxacillin dry cow therapy. Overall, the presence of resistance genes remains low and current antimicrobial usage patterns do not appear to be driving AMR in S. aureus associated with bovine mastitis.
Transmission dynamics of an antimicrobial resistant Campylobacter jejuni lineage in New Zealand’s commercial poultry network
(Elsevier B.V, 2021-12) Greening SS; Zhang J; Midwinter AC; Wilkinson DA; Fayaz A; Williamson DA; Anderson MJ; Gates MC; French NP
Understanding the relative contribution of different between-farm transmission pathways is essential in guiding recommendations for mitigating disease spread. This study investigated the association between contact pathways linking poultry farms in New Zealand and the genetic relatedness of antimicrobial resistant Campylobacter jejuni Sequence Type 6964 (ST-6964), with the aim of identifying the most likely contact pathways that contributed to its rapid spread across the industry. Whole-genome sequencing was performed on 167C. jejuni ST-6964 isolates sampled from across 30 New Zealand commercial poultry enterprises. The genetic relatedness between isolates was determined using whole genome multilocus sequence typing (wgMLST). Permutational multivariate analysis of variance and distance-based linear models were used to explore the strength of the relationship between pairwise genetic associations among the C. jejuni isolates and each of several pairwise distance matrices, indicating either the geographical distance between farms or the network distance of transportation vehicles. Overall, a significant association was found between the pairwise genetic relatedness of the C. jejuni isolates and the parent company, the road distance and the network distance of transporting feed vehicles. This result suggests that the transportation of feed within the commercial poultry industry as well as other local contacts between flocks, such as the movements of personnel, may have played a significant role in the spread of C. jejuni. However, further information on the historical contact patterns between farms is needed to fully characterise the risk of these pathways and to understand how they could be targeted to reduce the spread of C. jejuni.
Transmission Dynamics of Shiga Toxin-Producing Escherichia coli in New Zealand Cattle from Farm to Slaughter.
(American Society for Microbiology, 2021-05-11) Browne AS; Midwinter AC; Withers H; Cookson AL; Biggs PJ; Marshall JC; Benschop J; Hathaway S; Rogers L; Nisa S; Hranac CR; Winkleman T; French NP
Cattle are asymptomatic carriers of Shiga toxin-producing Escherichiacoli (STEC) strains that can cause serious illness or death in humans. In New Zealand, contact with cattle feces and living near cattle populations are known risk factors for human STEC infection. Contamination of fresh meat with STEC strains also leads to the potential for rejection of consignments by importing countries. We used a combination of PCR/matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) and whole-genome sequencing (WGS) to evaluate the presence and transmission of STEC on farms and in processing plants to better understand the potential pathways for human exposure and thus mitigate risk. Animal and environmental samples (n = 2,580) were collected from six farms and three meat processing plants in New Zealand during multiple sampling sessions in spring of 2015 and 2016. PCR/MALDI-TOF analysis revealed that 6.2% were positive for "Top 7" STEC. Top 7 STEC strains were identified in all sample sources (n = 17) tested. A marked increase in Top 7 STEC prevalence was observed between calf hides on farm (6.3% prevalence) and calf hides at processing plants (25.1% prevalence). Whole-genome sequencing was performed on Top 7 STEC bacterial isolates (n = 40). Analysis of STEC O26 (n = 25 isolates) revealed relatively low genetic diversity on individual farms, consistent with the presence of a resident strain disseminated within the farm environment. Public health efforts should focus on minimizing human contact with fecal material on farms and during handling, transport, and slaughter of calves. Meat processing plants should focus on minimizing cross-contamination between the hides of calves in a cohort during transport, lairage, and slaughter. IMPORTANCE Cattle are asymptomatic carriers of Shiga toxin-producing E. coli (STEC) strains, which can cause serious illness or death in humans. Contact with cattle feces and living near cattle are known risk factors for human STEC infection. This study evaluated STEC carriage in young calves and the farm environment with an in-depth evaluation of six farms and three meat processing plants over 2 years. An advanced molecular detection method and whole-genome sequencing were used to provide a detailed evaluation of the transmission of STEC both within and between farms. The study revealed widespread STEC contamination within the farm environment, but no evidence of recent spread between farms. Contamination of young dairy calf hides increased following transport and holding at meat processing plants. The elimination of STEC in farm environments may be very difficult given the multiple transmission routes; interventions should be targeted at decreasing fecal contamination of calf hides during transport, lairage, and processing.
Updating the genomic taxonomy and epidemiology of Campylobacter hyointestinalis
(Springer Nature Limited, 2018-02-05) Wilkinson DA; O'Donnell AJ; Akhter RN; Fayaz A; Mack HJ; Rogers LE; Biggs PJ; French NP; Midwinter AC
Campylobacter hyointestinalis is a member of an emerging group of zoonotic Campylobacter spp. that are increasingly identified in both gastric and non-gastric disease in humans. Here, we discovered C. hyointestinalis in three separate classes of New Zealand ruminant livestock; cattle, sheep and deer. To investigate the relevance of these findings we performed a systematic literature review on global C. hyointestinalis epidemiology and used comparative genomics to better understand and classify members of the species. We found that C. hyointestinalis subspecies hyointestinalis has an open pangenome, with accessory gene contents involved in many essential processes such as metabolism, virulence and defence. We observed that horizontal gene transfer is likely to have played an overwhelming role in species diversification, favouring a public-goods-like mechanism of gene ‘acquisition and resampling’ over a tree-of-life-like vertical inheritance model of evolution. As a result, simplistic gene-based inferences of taxonomy by similarity are likely to be misleading. Such genomic plasticity will also mean that local evolutionary histories likely influence key species characteristics, such as host-association and virulence. This may help explain geographical differences in reported C. hyointestinalis epidemiology and limits what characteristics may be generalised, requiring further genomic studies of C. hyointestinalis in areas where it causes disease.

Browsing by Author "Midwinter AC"

Results Per Page

Sort Options