Healthy poultry can be a reservoir for extraintestinal pathogenic Escherichia coli (ExPEC), some of which could be multidrug resistant to antimicrobials. These ExPEC strains could contaminate the environment and/or food chain representing thus, food safety and human health risk. However, few studies have shown the virulence of poultry-source antimicrobial-resistant (AMR) ExPEC in humans. This study characterized AMR ExPEC and investigated the virulence potential of some of their isolates in a Caenorhabditis elegans infection model. A total of 46 E. coli isolates from poultry (chicken, n = 29; turkey, n = 12) retail meats and chicken feces (n = 4), or humans (n = 1) were sequenced and identified as ExPEC. Except eight, all remaining 38 ExPEC isolates were resistant to at least one antibiotic and carried corresponding antimicrobial resistance genes (ARGs). About 27 of the 46 ExPEC isolates were multidrug-resistant (≥3 antibiotic classes). Seven ExPEC isolates from chicken or turkey meats were of serotype O25:H4 and sequence type (ST) 131 which clustered with an isolate from a human urinary tract infection (UTI) case having the same serotype and ST. The C. elegans challenge model using eight of studied ExPEC isolates harboring various ARGs and virulence genes (VGs) showed that regardless of their ARG or VG numbers in tested poultry meat and feces, ExPEC significantly reduced the life span of the nematode (P < 0.05) similarly to a human UTI isolate. This study indicated the pathogenic potential of AMR ExPEC from retail poultry meat or feces, but more studies are warranted to establish their virulence in poultry and human. Furthermore, relationships between specific resistance profiles and/or VGs in these E. coli isolates for their pathogenicity deserve investigations.
Abstract This study investigated virulence potential of poultry antimicrobial resistant extraintestinal pathogenic E. coli (ExPEC). A total of 46 E. coli isolates from poultry meat, feces, or humans were sequenced and identified as ExPEC. Based on their characteristics, eight of these ExPEC isolates were evaluated for their potentials using a Caenorhabditis elegans infection model. The life-span of C. elegans in response to these eight isolates was examined in three life-span experiments: 1) E. coli OP 50 (negative control), K88+ enterotoxigenic E. coli strain JG280 (positive control), and an ExPEC isolate from human urinal tract infection; 2) three ExPEC isolates from chicken and turkey retail meats; 3) four ExPEC isolates from chicken feces with different antimicrobial resistance (AMR) profiles or a various number of virulence genes (VGs). All 46 isolates belonged to 24 serotypes among which 6 were of serotype O25:H4 Sequence Type 131 (ST131). Interestingly, all ST 131 isolates from chicken or turkey retail meats clustered with a human UTI isolate belonging to the similar serotype and ST type. The types and numbers of AGRs and VGs varied among the eight selected isolates for C. elegans model. The human ExPEC induced a similar effect as the JG280 on reducing (P < 0.05) survival of C. elegans. Interestingly, chicken and turkey meat ExPEC isolates, caused similar negative impacts on the survival of worms as the human ExPEC. Additionally, fecal ExPEC isolates reduced (P < 0.05) the survival of C. elegans compared to OP50. However, the survival of C. elegans was not reduced with an increasing number of VGs and did not seem to be affected by AMR profiles. This study indicated the virulence potential of ExPEC isolates from retail poultry meat or feces. The relationship between specific AMR profiles and/or numbers of VGs with pathogenicity in these E. coli isolates deserves further investigations.
Harmful cyanobacterial blooms produce cyanotoxins which can adversely affect humans and animals. Without proper monitoring and detection programs, tragedies such as the loss of pets or worse are possible. Multiple factors including rising temperatures and human influence contribute to the increased likelihood of harmful cyanobacteria blooms. Current approaches to monitoring cyanobacteria and their toxins include microscopic methods, immunoassays, liquid chromatography coupled with mass spectrometry (LCMS), molecular methods such as qPCR, satellite monitoring, and, more recently, machine learning models. This review highlights current research into early detection methods for harmful cyanobacterial blooms and the pros and cons of these methods.
We previously described Salmonella enterica serovar Heidelberg isolates harboring a chromosomal gene cluster similar to the glutathione S-transferase gene, a putative fosA gene conferring resistance to fosfomycin. Here, we show that this new gene, named fosA7, confers resistance to fosfomycin. The introduction of fosA7 into the fosfomycin-susceptible Salmonella enterica serovar Enteritidis resulted in a substantial increase in the fosfomycin MIC. This finding increases the awareness of antibiotic resistance in Salmonella Heidelberg from broilers as related to the food safety and public health.
Abstract This study investigated effects of in-feed encapsulated cinnamaldehyde (CIN) and citral (CIT) alone or in combination (CIN+CIT) on antimicrobial resistance (AMR) phenotypes and genotypes of E. coli isolated from feces of 6-, 16-, 23- and 27-days old broiler chickens. Five dietary treatments included the basal diet (NC), the basal diet supplemented with 55 ppm bacitracin (BAC), 100 ppm encapsulated CIN, CIT, or CIN+CIT. Antimicrobial susceptibility using a Sensititre method of 240 E. coli isolates showed that the most frequent resistances were against b-lactam, aminoglycoside, sulfonamide and tetracycline, however, the prevalence of AMR decreased (P < 0.05) when birds aged. The prevalence of resistance to amoxicillin-clavulanic acid, ceftiofur, ceftriaxone, cefoxitin, gentamicin, and sulfonamide was lower (P < 0.05) in isolates from CIN or CIN+CIT compared to those from NC or BAC. The whole-genome sequencing analysis of 227 of the 240 isolates detected 26 AMR genes (ARGs) and 19 plasmids but the prevalence of some ARGs and plasmid numbers were lower (P < 0.05) in E. coli isolated from CIN or CIN+CIT than NC or BAC. The most prevalent resistance genes included tet(A) (n = 108), aac3_Vla (n = 91), aadA1 (n = 86), blaCMY-2 (n = 78), sul1 (n = 77), aph3_lb (n = 58), aph6_ld (n = 58), and sul2 (n = 24). Interestingly, the number of most virulence genes (VGs) increased (P < 0.05) over time from 6 to 27 days of age. The prevalence of isolates of serotype O21:H16 was lower (P < 0.05) in CIN and CIN+CIT while colibacillosis-associated multi-locus sequence typing (ST117) was the most prevalent in isolates from day 23. A whole genome-based phylogenetic tree revealed a close relationship of 25 of 227 isolates to human or broiler extraintestinal pathogenic E. coli. This study indicates that AMR and virulence genotypes of E. coli could be modulated by encapsulated CIN or CIN+CIT feed supplementations and prompt further investigations on the involved mechanisms.
The establishment of silent chromatin requires passage through S-phase, but not DNA replication per se. Nevertheless, many proteins that affect silencing are bona fide DNA replication factors. It is not clear if mutations in these replication factors affect silencing directly or indirectly via deregulation of S-phase or DNA replication. Consequently, the relationship between DNA replication and silencing remains an issue of debate. Here we analyze the effect of mutations in DNA replication factors (mcm5-461, mcm5-1, orc2-1, orc5-1, cdc45-1, cdc6-1, and cdc7-1) on the silencing of a group of reporter constructs, which contain different combinations of "natural" subtelomeric elements. We show that the mcm5-461, mcm5-1, and orc2-1 mutations affect silencing through subtelomeric ARS consensus sequences (ACS), while cdc6-1 affects silencing independently of ACS. orc5-1, cdc45-1, and cdc7-1 affect silencing through ACS, but also show ACS-independent effects. We also demonstrate that isolated nontelomeric ACS do not recapitulate the same effects when inserted in the telomere. We propose a model that defines the modes of action of MCM5 and CDC6 in silencing.
The Canadian Genomics Research and Development Initiative for Antimicrobial Resistance (GRDI-AMR) uses a genomics-based approach to understand how health care, food production and the environment contribute to the development of antimicrobial resistance. Integrating genomics contextual data streams across the One Health continuum is challenging because of the diversity in data scope, content and structure. To better enable data harmonization for analyses, a contextual data standard was developed. However, development of standards does not guarantee their use. Implementation strategies are critical for putting standards into practice. This work focuses on the development of implementation strategies to better operationalize data standards across the Canadian federal genomics ecosystem. Results include improved understanding of complex data models that can create challenges for existing systems. Technical implementation strategies included spreadsheet-based solutions, new exchange formats, and direct standards integration into new databases. Data curation exercises highlighted common data collection and sharing issues, which informed improved practices and evaluation procedures. These new practices are contributing to improved data quality and sharing within the GRDI-AMR consortium as evidenced by publicly available datasets. The implementation strategies and lessons learned described in this work are generalizable for other standards and can be applied more broadly within other initiatives.
Enteritidis and Typhimurium are among the top Salmonella enterica serovars implicated in human salmonellosis worldwide. This study examined the individual and combined roles of catecholate-iron and hydroxamate-iron transporters in the survival in meat of Salmonella Enteritidis and Typhimurium. Catecholate-iron-III (Fe3+) and hydroxamate-Fe3+ transporter genes fepA, iroN, and fhuACDB were deleted in isolates of these serovars to generate single, double, and triple mutants. Growth rate in high- and low-iron media was compared among mutants, complements, and their wild-type parents. Susceptibility to 14 antibiotics, the ability to produce and utilize siderophores, and survival on cooked chicken breast were evaluated. In iron-poor liquid media, differences were observed between the growth characteristics of mutant Salmonella Enteritidis and Typhimurium. The double Δ iroNΔ fepA and the triple Δ fhuΔ iroNΔ fepA mutants of Salmonella Enteritidis exhibited prolonged lag phases (λ = 9.72 and 9.53 h) and a slow growth rate (μmax = 0.35 and 0.25 h-1) similar to that of its Δ tonB mutant (λ = 10.12 h and μmax = 0.30 h-1). In Salmonella Typhimurium, double Δ iroNΔ fepA and triple Δ fhuΔ iroNΔ fepA mutations induced a similar growth pattern as its Δ tonB mutant. Double deletions of fepA and iroN reduced the siderophore production and the use of enterobactin as an iron source. In the Δ iroNΔ fepA mutant, but not in Δ fhuΔ iroNΔ fepA, the ferrichrome or deferrioxamine promoted growth for both serovars, confirming the specific role of the FhuACDB system in the uptake and transport of hydroxamate Fe3+. Survival of the mutants was also evaluated in a meat assay, and no difference in survival was observed among the mutants compared with wild type. This study showed differences between serovars in the importance of catecholate-iron and hydroxamate-iron uptake on Salmonella growth in iron-restricted media. Data also confirmed that both Salmonella Enteritidis and Typhimurium are well equipped to survive on cooked chicken meat, offering a rich iron condition.
Extraintestinal pathogenic Escherichia coli (ExPEC) include several serotypes that have been associated with colibacillosis in poultry and with urinary tract infections (UTIs) and newborn meningitis in humans. In this study, 57 antimicrobial-resistant E. coli from apparently healthy broiler chickens were characterized for their health and safety risks. These isolates belonged to 12 serotypes, and isolates of the same serotype were clonal based on single nucleotide variant analysis. Most of the isolates harbored plasmids; IncC and IncFIA were frequently detected. The majority of the resistant isolates harbored plasmid-mediated resistance genes, including aph(3″)-Ib, aph(6)-Id, blaCMY-2, floR, sul1, sul2, tet(A), and tet(B), in agreement with their resistant phenotypes. The class 1 integron was detected in all E. coli serotypes except O124:H25 and O7:H6. Of the 57 broiler E. coli isolates, 27 were avian pathogenic, among which 18 were also uropathogenic E. coli and the remainder were other ExPEC. The two isolates of serotype O161:H4 (ST117) were genetically related to the control avian pathogenic strains and a clinical isolate associated with UTIs. A strain of serotype O159:H45 (ST101) also was closely related to a UTI isolate. The detected virulence factors included adhesins, invasins, siderophores, type III secretion systems, and toxins in combination with other virulence determinants. A broiler isolate of serotype O7:H18 (ST38) carried the ibeA gene encoding a protein involved in invasion of brain endothelium on a 102-kbp genetic island. This isolate moderately adhered and invaded Caco-2 cells and induced mortality (42.5%) in a day-old-chick infection model. The results of this study suggest that multiple antimicrobial-resistant E. coli isolates recovered from apparent healthy broilers can be pathogenic and act as reservoirs for antimicrobial resistance genes, highlighting the necessity of their assessment in a "One-Heath" context.
