Extraintestinal Infections In Humans Research Articles

Phenotypic and genotypic characterization of Escherichia coli isolated from the chicken liver in relation to slaughterhouse conditions

Avian pathogenic Escherichia coli (APEC) has been identified as a sub-group of extraintestinal pathogenic E. coli (ExPEC). Recent studies indicate APEC as a potential foodborne zoonotic pathogen and a source or reservoir of human extraintestinal infections. The slaughtering and processing of poultry in low-income countries such as Jordan occurs in two distinct ways: in informal facilities known as Natafat and in formal slaughterhouses. This study compared E. coli phenotypes and genotypes according to slaughtering conditions (formal slaughterhouses vs. informal slaughter facilities). Therefore, liver samples (n = 242) were collected from formal (n = 121) and informal slaughter facilities (n = 121). Results revealed a high prevalence (94.2%) of E. coli among all isolates, with 59 (17 formal and 42 informal) isolates considered avian pathogenic E. coli (APEC) based on the virulence-associated genes. The prevalence of resistance among isolates was relatively high, reaching up to 99% against penicillin and 97% against nalidixic acid. However, the prevalence of resistance was the lowest (1.3%) against both meropenem and imipenem. Based on the MIC test findings, colistin resistance was 46.9% (107/228). The mcr −1 gene prevalence was 51.4% (55/107), of which 17.1 % were from formal plants (6/36) and 68.1% from informal facilities (49/72). Interestingly, only one isolate (0.9%) expressed mcr-10. Escherichia coli O157:H7 and associated virulence genes were found more in informal (n = 15 genes) than in formal slaughterhouses (n = 8). Phylogroups B1, C, and A were the most frequent in 228 E. coli isolates, while G, B2, and clade were the least frequent. In conclusion, these findings highlight the importance of implementing biosecurity measures in slaughterhouses to reduce antibiotic-resistant E. coli spread. Furthermore, this study provides valuable insights into the effects of wet market (Natafat) slaughter conditions on increasing bacterial resistance and virulence.

Molecular Detection of Virulence-Associated Markers in Campylobacter coli and Campylobacter jejuni Isolates From Water, Cattle, and Chicken Faecal Samples From Kajiado County, Kenya.

Campylobacter is a zoonotic foodborne pathogen that is often linked with gastroenteritis and other extraintestinal infections in humans. This study is aimed at determining the genetic determinants of virulence-encoding genes responsible for flagellin motility protein A (flaA), Campylobacter adhesion to fibronectin F (cadF), Campylobacter invasion antigen B (ciaB) and cytolethal distending toxin (cdt) A (cdtA) in Campylobacter species. A total of 29 Campylobacter coli isolates (16 from cattle, 9 from chicken, and 4 from water samples) and 74 Campylobacter jejuni isolates (38 from cattle, 30 from chicken, and 6 from water samples) described in an earlier study in Kajiado County, Kenya, were examined for the occurrence of virulence-associated genes using polymerase chain reaction (PCR) and amplicon sequencing. The correlations among virulence genes were analyzed using Pearson's correlation coefficient (R) method. Among the 103 Campylobacter strains screened, 89 were found to harbour a single or multiple virulence gene(s), giving an overall prevalence of 86.4%. C. jejuni strains had the highest prevalence of multivirulence at 64.9% (48/74), compared to C. coli (58.6%, 17/29). The ciaB and flaA genes were the most common virulence genes detected in C. jejuni (81.1% [60/74] and 62.2% [46/74], respectively) and in C. coli (each at 62.1%; 18/29). Campylobacter isolates from chicken harboured the most virulence-encoding genes. C. jejuni strains from chicken and cattle harboured the highest proportions of the cdtA and ciaB genes, respectively. All the C. coli strains from water samples harboured the cadF and flaA genes. The results obtained further revealed a significant positive correlation between cadF and flaA (R = 0.733). C. jejuni and C. coli strains from cattle, chicken, and water harbour virulence markers responsible for motility/colonization, invasion, adherence, and toxin production, evoking their important role in campylobacteriosis development among humans and livestock. The identification of cattle, chicken, and water samples as reservoirs of virulent Campylobacter spp. highlights the possible risk to human health. These data on some virulence genes of Campylobacter will assist food safety and public health officials in formulating policy statements.

Genome-Wide Analysis of Escherichia coli Isolated from Dairy Animals Identifies Virulence Factors and Genes Enriched in Multidrug-Resistant Strains.

The gastrointestinal tracts of dairy calves and cows are reservoirs of antimicrobial-resistant bacteria (ARB), which are present regardless of previous antimicrobial therapy. Young calves harbor a greater abundance of resistant bacteria than older cows, but the factors driving this high abundance are unknown. Here, we aimed to fully characterize the genomes of multidrug-resistant (MDR) and antimicrobial-susceptible Escherichia coli strains isolated from pre-weaned calves, post-weaned calves, dry cows, and lactating cows and to identify the accessory genes that are associated with the MDR genotype to discover genetic targets that can be exploited to mitigate antimicrobial resistance in dairy farms. Results indicated that both susceptible and resistant E. coli isolates recovered from animals on commercial dairy operations were highly diverse and encoded a large pool of virulence factors. In total, 838 transferrable antimicrobial resistance genes (ARGs) were detected, with genes conferring resistance to aminoglycosides being the most common. Multiple sequence types (STs) associated with mild to severe human gastrointestinal and extraintestinal infections were identified. A Fisher's Exact Test identified 619 genes (ARGs and non-ARGs) that were significantly enriched in MDR isolates and 147 genes that were significantly enriched in susceptible isolates. Significantly enriched genes in MDR isolates included the iron scavenging aerobactin synthesis and receptor genes (iucABCD-iutA) and the sitABCD system, as well as the P fimbriae pap genes, myo-inositol catabolism (iolABCDEG-iatA), and ascorbate transport genes (ulaABC). The results of this study demonstrate a highly diverse population of E. coli in commercial dairy operations, some of which encode virulence genes responsible for severe human infections and resistance to antibiotics of human health significance. Further, the enriched accessory genes in MDR isolates (aerobactin, sit, P fimbriae, and myo-inositol catabolism and ascorbate transport genes) represent potential targets for reducing colonization of antimicrobial-resistant bacteria in the calf gut.

A-263 Prevalence and Antimicrobial Susceptibility Profiles of Escherichia coli Isolated from Retail Meat Products Imported from USA and Domestically Produced on Caribbean Islands of St. Kitts and Grenada

Abstract Background Escherichia coli (E. coli) is a commensal flora of the gastrointestinal tract of humans and livestock animals. However, pathogenic and opportunistic variants are becoming a significant cause for concern in human healthcare (CDC, 2014). The emergence of these resistant strains is attributed to the overuse of antibiotics in agricultural practices (Llor, 2014). These microbes carry antimicrobial resistance (AMR) genetic markers that cause severe complications in treating intestinal and extra-intestinal infections in humans (Crecencio, 2020). The role of global meat industrialization and trade as a potential reservoir and source of transmission for AMR bacteria is considered a priority for OneHealth Initiatives, with collaborations between researchers, physicians, veterinarians, and food industries. Methods This study aims to compare the prevalence and antimicrobial susceptibility profiles of E. coli isolated from pork and poultry products imported from the USA to those domestically produced on the Caribbean Islands of St. Kitts and Grenada. This study was conducted over a 6-year period at the University of Medicine and Health Sciences (UMHS) in St Kitts and St. George’s University (SGU) in Grenada. Meat product samples were collected from retail stores around the Caribbean Islands. These meat samples were incubated at 36°C in Buffered media for 60 min and 24 h, then spread onto MacConkey agar to select for Gram-negative bacterial isolates. Lactose fermenting colonies were isolated and subcultured onto Nutrient agar. Species identification was performed using standard biochemical assays and Biomerieux API-20E test kits. Isolates were introduced to Mueller Hinton agar, and antimicrobial susceptibility was tested using the Kirby-Bauer disc diffusion. Results 100 meat product samples (50 domestic, 50 imported) were processed for investigation on the Caribbean Islands. On the Island of St. Kitts, 64 and 60 bacterial colonies were isolated from the domestic and imported samples, respectively. The prevalence of E. coli was 16% (n = 20) for imported samples and 12% (n = 15) for domestically produced samples. As Multiple drug resistance to >3 classes of antibiotics in E. coli isolates was 50% of imported isolates and 27% domestically produced. Resistance to amoxicillin was observed in 60% and 33% of E. coli isolates from Imported and Domestic origins, respectively. Resistance to trimethoprim-sulfamethoxazole was 25% and 13% in imported and domestic, respectively. Resistance to ciprofloxacin was 35% and 27% for imported and domestic, respectively. Resistance to cephalosporins was 60% in isolates from imported meat products and 33% in isolates from meat products domestically produced on the island of St. Kitts. Investigations are still ongoing for bacteria colony isolates from meat product samples from Grenada. Conclusion Imported meats products exhibit a higher prevalence of resistant E. coli, particularly in the beta-lactam class of antibiotics, including amoxicillin and cephalosporins. Therefore, the risk of importing meat products is a concern for introduction of AMR genetic markers to human populations. Active surveillance must be conducted to better understand the risk of exposure to humans from contaminated retail meat products to inform antibiotic therapy and resistance control continuously.

Phylogeny, Virulence, and Antimicrobial Resistance Gene Profiles of Enterococcus faecium Isolated from Australian Feedlot Cattle and Their Significance to Public and Environmental Health.

The extent of similarity between E. faecium strains found in healthy feedlot beef cattle and those causing extraintestinal infections in humans is not yet fully understood. This study used whole-genome sequencing to analyse the antimicrobial resistance profile of E. faecium isolated from beef cattle (n = 59) at a single feedlot and compared them to previously reported Australian isolates obtained from pig (n = 60) and meat chicken caecal samples (n = 8), as well as human sepsis cases (n = 302). The E. faecium isolated from beef cattle and other food animal sources neither carried vanA/vanB responsible for vancomycin nor possessed gyrA/parC and liaR/liaS gene mutations associated with high-level fluoroquinolone and daptomycin resistance, respectively. A small proportion (7.6%) of human isolates clustered with beef cattle and pig isolates, including a few isolates belonging to the same sequence types ST22 (one beef cattle, one pig, and two human isolates), ST32 (eight beef cattle and one human isolate), and ST327 (two beef cattle and one human isolate), suggesting common origins. This provides further evidence that these clonal lineages may have broader host range but are unrelated to the typical hospital-adapted human strains belonging to clonal complex 17, significant proportions of which contain vanA/vanB and liaR/liaS. Additionally, none of the human isolates belonging to these STs contained resistance genes to WHO critically important antimicrobials. The results confirm that most E. faecium isolated from beef cattle in this study do not pose a significant risk for resistance to critically important antimicrobials and are not associated with current human septic infections.

Phylogenetic Analysis of Escherichia coli Isolated from Australian Feedlot Cattle in Comparison to Pig Faecal and Poultry/Human Extraintestinal Isolates.

The similarity of commensal Escherichia coli isolated from healthy cattle to antimicrobial-resistant bacteria causing extraintestinal infections in humans is not fully understood. In this study, we used a bioinformatics approach based on whole genome sequencing data to determine the genetic characteristics and phylogenetic relationships among faecal Escherichia coli isolates from beef cattle (n = 37) from a single feedlot in comparison to previously analysed pig faecal (n = 45), poultry extraintestinal (n = 19), and human extraintestinal E. coli isolates (n = 40) from three previous Australian studies. Most beef cattle and pig isolates belonged to E. coli phylogroups A and B1, whereas most avian and human isolates belonged to B2 and D, although a single human extraintestinal isolate belonged to phylogenetic group A and sequence type (ST) 10. The most common E. coli sequence types (STs) included ST10 for beef cattle, ST361 for pig, ST117 for poultry, and ST73 for human isolates. Extended-spectrum and AmpC β-lactamase genes were identified in seven out of thirty-seven (18.9%) beef cattle isolates. The most common plasmid replicons identified were IncFIB (AP001918), followed by IncFII, Col156, and IncX1. The results confirm that feedlot cattle isolates examined in this study represent a reduced risk to human and environmental health with regard to being a source of antimicrobial-resistant E. coli of clinical importance.

Genomics, biofilm formation and infection of bladder epithelial cells in potentially uropathogenic Escherichia coli (UPEC) from animal sources and human urinary tract infections (UTIs) further support food-borne transmission

Escherichia coli is the main cause of urinary tract infections (UTI). While genomic comparison of specific clones recovered from animals, and human extraintestinal infections show high identity, studies demonstrating the uropathogenicity are lacking. In this study, comparative genomics combined with bladder-cell and biofilm formation assays, were performed for 31 E. coli of different origins: 7 from meat (poultry, beef, and pork); 2 from avian-farm environment; 12 from human uncomplicated UTI, uUTI; and 10 from human complicated UTI, cUTI. These isolates were selected based on their genetic uropathogenic (UPEC) status and phylogenetic background. In silico analysis revealed similar virulence-gene profiles, with flagella, type 1 and curli fimbriae, outer-membrane proteins (agn43, ompT, iha), and iron-uptake (iutA, entA, and fyuA) associated-traits as the most prevalent (>65%). In bladder-cell assays, moderate to strong values of association (83%, 60%, 77.8%) and invasion (0%, 70%, 55.5%) were exhibited by uUTI, cUTI, and animal-derived isolates, respectively. Of interest, uUTI isolates exhibited a significantly lower invasive capacity than cUTI isolates (p < 0.05). All isolates but one produced measurable biofilm. Notably, 1 turkey meat isolate O11:H6-F-ST457, and 2 cUTI isolates of the pandemic lineages O83:H42-F-ST1485-CC648 and O25b:H4-B2-ST131, showed strong association, invasion and biofilm formation. These isolates showed common carriage of type 1 fimbriae and csg operons, toxins (hlyF, tsh), iron uptake systems (iutA, entA, iroN), colicins, protectins (cvaC, iss, kpsM, traT), ompT, and malX. In summary, the similar in vitro behaviour found here for certain E. coli clones of animal origin would further reinforce the role of food-producing animals as a potential source of UPEC. Bladder-cell infection assays, combined with genomics, might be an alternative to in vivo virulence models to assess uropathogenicity.

Escherichia coli multilocus sequence type 38 from humans and broiler production represent distinct monophyletic groups.

Escherichia coli belonging to multilocus sequence type 38 (ST38) is a well-known cause of extra-intestinal infections in humans, and are frequently associated with resistance to extended-spectrum cephalosporins (ESCs). Resistance to carbapenems, mediated by blaOXA-genes has also been reported in this ST. Recently, the European Centre for Disease Prevention and Control (ECDC) released a rapid risk assessment on the increased detection of OXA-244 producing E. coli ST38 in humans, requesting further knowledge to determine the source. ST38 is also one of the most common STs among ESC-resistant E. coli from broiler production. Our aim was to investigate the genetic characteristics and relationship between E. coli ST38 from broiler production and humans, and to investigate if there has been a potential spillover between these sources. A total of 288 E. coli ST38 genomes isolated from humans in Europe (collected 2009-2019) and from Nordic broiler production (collected 2011-2014) were analyzed. The results showed distinct monophyletic clades associated to humans and broiler production. Furthermore, there were differences in the ESC resistance genes present in E. coli ST38 from the two sources. The blaOXA-244 gene was not present in E. coli from broiler production. Our results show that ST38 from humans and broiler production belong to well-separated clades, and suggest that the increased detection of OXA-244-producing E. coli ST38 in humans is not associated with spillover from broiler production.

Identification of genes influencing the evolution of Escherichia coli ST372 in dogs and humans.

ST372 are widely reported as the major Escherichia coli sequence type in dogs globally. They are also a sporadic cause of extraintestinal infections in humans. Despite this, it is unknown whether ST372 strains from dogs and humans represent shared or distinct populations. Furthermore, little is known about genomic traits that might explain the prominence of ST372 in dogs or presence in humans. To address this, we applied a variety of bioinformatics analyses to a global collection of 407 ST372 E. coli whole-genome sequences to characterize their epidemiological features, population structure and associated accessory genomes. We confirm that dogs are the dominant host of ST372 and that clusters within the population structure exhibit distinctive O:H types. One phylogenetic cluster, 'cluster M', comprised almost half of the sequences and showed the divergence of two human-restricted clades that carried different O:H types to the remainder of the cluster. We also present evidence supporting transmission between dogs and humans within different clusters of the phylogeny, including M. We show that multiple acquisitions of the pdu propanediol utilization operon have occurred in clusters dominated by isolates of canine source, possibly linked to diet, whereas loss of the pdu operon and acquisition of K antigen virulence genes characterize human-restricted lineages.

Global Genomic Epidemiology of Escherichia coli (ExPEC) ST38 Lineage Revealed a Virulome Associated with Human Infections.

Most of the extraintestinal human infections worldwide are caused by specific extraintestinal pathogenic Escherichia coli (ExPEC) lineages, which also present a zoonotic character. One of these lineages belongs to ST38, a high-risk globally disseminated ExPEC. To get insights on the aspects of the global ST38 epidemiology and evolution as a multidrug-resistant and pathogenic lineage concerning the three axes of the One Health concept (humans, animals, and natural environments), this study performed a global phylogenomic analysis on ST38 genomes. A phylogenetic reconstruction based on 376 ST38 genomes recovered from environments, humans, livestock, and wild and domestic animals in all continents throughout three decades was performed. The global information concerning the ST38 resistome and virulome was also approached by in silico analyses. In general, the phylogenomic analyses corroborated the zoonotic character of the ExPEC ST38, since clonal strains were recovered from both animal and human sources distributed worldwide. Moreover, our findings revealed that, independent of host sources and geographic origin, the genomes were distributed in two major clades (Clades 1 and 2). However, the ST38 accessory genome was not strictly associated with clades and sub-clades, as found for the type 2 T3SS ETT2 that was evenly distributed throughout Clades 1 and 2. Of note was the presence of the Yersinia pestis-like high-pathogenicity island (HPI) exclusively in the major Clade 2, in which prevails most of the genomes from human origin recovered worldwide (2000 to 2020). This evidence corroborates the HPI association with successful E. coli ST38 establishment in human infections.

Global Phylogeny and F Virulence Plasmid Carriage in Pandemic Escherichia coli ST1193.

Lower urinary tract, renal, and bloodstream infections caused by phylogroup B2 extraintestinal pathogenic Escherichia coli (ExPEC) are a leading cause of morbidity and mortality. ST1193 is a phylogroup B2, multidrug-resistant sequence type that has risen to prominence globally, but a comprehensive analysis of the F virulence plasmids it carries is lacking. We performed a phylogenomic analysis of ST1193 (n = 707) whole-genome sequences from EnteroBase using entries with comprehensive isolation metadata. The data set comprised isolates from humans (n = 634 [90%]), including 339 (48%) from extraintestinal infection sites, and isolates from companion animals, wastewater, and wildlife. Phylogenetic analyses combined with gene detection and genotyping resolved an ST1193 clade structure segregated by serotype and F plasmid carriage. Most F plasmids fell into one of three related plasmid subtypes: F-:A1:B10 (n = 444 [65.97%]), F-:A1:B1 (n = 84 [12.48%]), and F-:A1:B20 (n = 80 [11.89%]), all of which carry the virulence genes cjrABC colocalized with senB (cjrABC-senB), a trademark signature of F29:A-:B10 subtype plasmids (pUTI89). To examine the phylogenetic relationship of these plasmids with pUTI89, complete sequences of F-:A1:B1 and F-:1:B20 plasmids were resolved. Unlike pUTI89, the most dominant and widely disseminated F plasmid that carries cjrABC-senB, F plasmids in ST1193 often carry a complex resistance region with an integron truncation (intI1Δ745) signature embedded within a structure assembled by IS26. Plasmid analysis shows that ST1193 has F plasmids that carry cjrABC-senB and ARG-encoding genes but lack tra regions and are likely derivatives of pUTI89. Further epidemiological investigation of ST1193 should seek to confirm its presence in human-associated environments and identify any potential agricultural links, which are currently lacking. IMPORTANCE We have generated an updated ST1193 phylogeny using publicly available sequences, reinforcing previous assertions that Escherichia coli ST1193 is a human-associated lineage, with many examples sourced from human extraintestinal infections. ST1193 from urban-adapted birds, wastewater, and companion animals are frequent, but isolates from animal agriculture are notably absent. Phylogenomic analysis identified several clades segregated by serogroup, all noted to carry highly similar F plasmids and antimicrobial resistance (AMR) signatures. Investigation of these plasmids revealed virulence regions with similarity to pUTI89, a key F virulence plasmid among dominant pandemic extraintestinal pathogenic E. coli lineages, and encoding a complex antibiotic resistance structure mobilized by IS26. This work has uncovered a series of F virulence plasmids in ST1193 and shows that the lineage mimics the host range and virulence attributes of other E. coli strains that carry pUTI89. These observations have significant ramifications for epidemiological source tracking of emerging and established pandemic ExPEC lineages.

Effects of TolC on the pathogenicity of porcine extraintestinal pathogenic Escherichia coli.

Extraintestinal pathogenic Escherichia coli (ExPEC) is a well-known critical pathogenic zoonosis that causes extraintestinal infections in humans and animals by affecting their immune organs. Recently, research on the outer membrane protein of E. coli, tolerant colicin (TolC), a virulent protein in the formation of the ExPEC efflux pump, has been an attractive subject. However, the pathogenic mechanisms remain unclear. This study aimed to explore the role of TolC in the pathogenesis of the ExPEC strain PPECC42; a complementation strain (Cm-TolC) and an isogenic mutant (ΔTolC) were constructed. Loss of TolC drastically impaired the virulence of ExPEC in an experimental mouse model. ΔTolC showed a substantial decrease in the porcine aortic vascular endothelial cell (PAVEC) adherence, invasion, and pro-inflammatory response, in contrast to that of the wild type, with a reduced survival ratio in both the bacterial load and whole blood in mice. ΔTolC also showed decreased expression of necroptosis signals such as receptor-interacting protein kinase 1, phosphorylated mixed-lineage kinase domain-like protein, and mitochondrial proteins such as phosphoglycerate mutase family member 5. Our data suggest that TolC is closely associated with ExPEC pathogenesis. These results provide scientific grounds for exploring the potential of TolC as an effective drug target for controlling ExPEC infection, screening new inhibitors, and developing new drugs. This will allow for further prevention and control of ExPEC infection.

Complete genomic analysis of ST117 lineage extraintestinal pathogenic Escherichia coli (ExPEC) to reveal multiple genetic determinants to drive its global transmission: ST117 E. coli as an emerging multidrug-resistant foodborne ExPEC with zoonotic potential.

Avian pathogenic Escherichia coli (APEC) is recognized as a primary source of foodborne extraintestinal pathogenic E. coli (ExPEC), which poses a significant risk of extraintestinal infections in humans. The potential of human infection with ST117 lineage APEC/ExPEC from poultry is particularly concerning. However, relatively few whole-genome studies have focused on ST117 as an emerging ExPEC lineage. In this study, the complete genomes of 11 avian ST117 isolates and the draft genomes of 20 ST117 isolates in China were sequenced to reveal the genomic islands and large plasmid composition of ST117 APEC. With reference to the extensive E. coli genomes available in public databases, large-scale comprehensive genomic analysis of the ST117 lineage APEC/ExPEC was performed to reveal the features of the ST117 pan-genome and population. The high variability of the accessory genome emphasized the diversity and dynamic traits of the ST117 pan-genome. ST117 isolates recovered from different hosts and geographic sources were randomly located on a phylogeny tree, suggesting that ST117 E. coli lacked host specificity. A time-scaled phylogeny tree showed that ST117 was a recent E. coli lineage with a relatively short evolutionary period. Further characterization of a wide diversity of ExPEC-related virulence genes, pathogenicity islands (PAIs), and resistance genes of the ST117 pan-genome provided insights into the virulence and resistance of ST117 APEC/ExPEC. The results suggested zoonotic potential of ST117 APEC/ExPEC between birds and humans. Moreover, genomic analysis showed that a pool of diverse plasmids drove the virulence and multidrug resistance of ST117 APEC/ExPEC. Several types of large plasmids were scattered across the ST117 isolates, but there was no strong plasmid-clade adaptation. Combined with the pan-genome analysis, a double polymerase chain reaction (PCR) method was designed for rapid and cost-effective detection of ST117 isolates from various avian and human APEC/ExPEC isolates. Overall, this study addressed a gap in current knowledge about the ST117 APEC/ExPEC genome, with significant implications to understand the success and spread of ST117 APEC/ExPEC.

High Prevalence of Beta-Lactam-Resistant Escherichia coli in South Australian Grey-Headed Flying Fox Pups (Pteropus poliocephalus).

The emergence of antimicrobial-resistant Escherichia coli in wildlife is concerning—especially resistance to clinically important beta-lactam antibiotics. Wildlife in closer proximity to humans, including in captivity and in rescue/rehabilitation centres, typically have a higher prevalence of antimicrobial-resistant E. coli compared to their free-living counterparts. Each year, several thousand Australian fruit bat pups, including the grey-headed flying fox (GHFF; Pteropus poliocephalus), require rescuing and are taken into care by wildlife rescue and rehabilitation groups. To determine the prevalence of beta-lactam-resistant E. coli in rescued GHFF pups from South Australia, faecal samples were collected from 53 pups in care. A combination of selective culture, PCR, antimicrobial susceptibility testing, whole-genome sequencing, and phylogenetic analysis was used to identify and genetically characterise beta-lactam-resistant E. coli isolates. The prevalence of amoxicillin-, amoxicillin-plus-clavulanic-acid-, and cephalosporin-resistant E. coli in the 53 pups was 77.4% (n = 41), 24.5% (n = 13), and 11.3% (n = 6), respectively. GHFF beta-lactam-resistant E. coli also carried resistance genes to aminoglycosides, trimethoprim plus sulphonamide, and tetracyclines in 37.7% (n = 20), 35.8% (n = 19), and 26.4% (n = 14) of the 53 GHFF pups, respectively, and 50.9% (n = 27) of pups carried multidrug-resistant E. coli. Twelve E. coli strain types were identified from the 53 pups, with six strains having extraintestinal pathogenic traits, indicating that they have the potential to cause blood, lung, or wound infections in GHFFs. Two lineages—E. coli ST963 and ST58 O8:H25—were associated with human extraintestinal infections. Phylogenetic analyses determined that all 12 strains were lineages associated with humans and/or domestic animals. This study demonstrates high transmission of anthropogenic-associated beta-lactam-resistant E. coli to GHFF pups entering care. Importantly, we identified potential health risks to GHFF pups and zoonotic risks for their carers, highlighting the need for improved antibiotic stewardship and biosafety measures for GHFF pups entering care.

Characterisation of Salmonella Enteritidis ST11 and ST1925 Associated with Human Intestinal and Extra-Intestinal Infections in Singapore.

Salmonella Enteritidis is a major foodborne pathogen worldwide. In this study, a total of 276 S. enteritidis isolates, collected between 2016 and 2017 from human, food and farm/slaughterhouse samples, were studied to enhance the understanding of the epidemiology of human salmonellosis in Singapore. Results showed all 276 isolates belonged either to ST1925 (70.3%) or ST11 (29.7%), with ST11 being significantly more frequent in extra-intestinal isolates and chicken isolates. Food isolates, most of which were from poultry, showed the highest prevalence of resistance (33–37%) against beta-lactams or beta-lactams/beta-lactamase inhibitor combination (ampicillin, piperacillin and ampicillin/sulbactam). The analysis showed the detection of genes associated with resistance to aminoglycoside genes (99.6%), tetracycline (55.1%), and beta-lactams (14.9%) of all isolates. Nine types of plasmids were found in 266 isolates; the most common incompatibility group profiles were IncFIB(S)-IncFII(S)-IncX1 (72.2%) and IncFIB(S)-IncFII(S) (15.8%). Most plasmid harbouring isolates from chicken (63.6%, 14/22) and from human (73.8%, 175/237) shared the same plasmid profile (IncFIB(S)-IncFII(S)-IncX1). SNP analysis showed clustering of several isolates from poultry food products and human isolates, suggesting phylogenetic relatedness among these isolates. Lastly, this study provides important epidemiological insights on the application of phenotypic and next-generation sequencing (NGS) tools for improved food safety and public health surveillance and outbreak investigation of S. enteritidis.

Fuzzy SEIR Epidemic Model of Amoebiasis Infection in Human

Amoebiasis is a disease caused by the protozoan Entamoeba histolytica. It is often asymptomatic but may cause dysentery and invasive extraintestinal infection in humans. To gain an understanding of the disease, a fuzzy SEIR model of amoebiasis infection is presented with the fuzziness introduced in the disease transmission rate, the disease-induced death rate, and the rate of recovery from infection. The basic reproduction number ℛ 0 v is computed and used to make a comparison with the fuzzy basic reproduction number ℛ 0 f at different amounts of cysts as well as to analyse the stability of equilibrium points. Stability results indicate that the disease-free equilibrium and the endemic equilibrium are locally and globally asymptotically stable. Further, numerical simulations are carried out to illustrate the analytical results of the fuzzy model system. The result shows that whenever there is an outbreak, the disease is likely to persist in the first month and thereafter it will start to slow down to disease-free equilibrium.

Molecular characterization and antimicrobial resistance profile of pathogenic Escherichia coli from goats with respiratory disease in eastern China

Pathogenic Escherichia coli (E. coli) can cause a variety of intestinal and extra-intestinal infections in humans and animals. Similar with the intestinal disease, respiratory disease is also a major threat to the breeding industry of goats. But the reports on respiratory disease associated E. coli are very limited. In this study, E. coli and other pathogens were examined for the 77 submitted respiratory cases. The serotypes, virulence genes, phylogenetic group and antimicrobial resistance characteristics of the E. coli isolates were identified. The results showed that 34 cases (44.16%) were associated with E. coli and 22 cases showed mixed infections of E. coli with Mycoplasma ovipneumoniae, Mannheimia haemolytica or Pasteurella . Among the 49 E. coli isolates, O8 (32.65%), O9 (20.41%) and O89 (10.20%) were the predominant serotypes (31/49, 63.27%). 22 virulence genes were detected and the most prevalent genes were fimH (100%), yijp (100%), mat (97.96%), ompA (95.92%) ibeB (91.84%) and fyuA (77.55%). In addition, ibeA was detected in 6.12% (3/49) of the strains. Markers of extra-intestinal pathogenic E. coli (ExPEC) were also identified and 14 strains were classified as ExPECs. 14 (28.57%), 25 (51.02%), 3 (6.12%) and 7 (14.29%) strains belonged to phylogenetic group A, B1, B2 and D, respectively, and group A and B1 were the predominant ones. The E. coli strains showed high resistant (48.98%–100%) to the 14 selected antimicrobials and all of them were defined as multiple drug resistant (MDR) strains. This is the first systemically study on E. coli of goats respiratory diseases origin in eastern China. The results suggest that E. coli infection may play an important role in goat respiratory diseases and that goats are reservoir hosts of ExPECs, which needs continuous monitoring in the future.

Outer membrane vesicles produced by pathogenic strains of Escherichia coli block autophagic flux and exacerbate inflammasome activation

Escherichia coli strains are responsible for a majority of human extra-intestinal infections, resulting in huge direct medical and social costs. We had previously shown that HlyF encoded by a large virulence plasmid harbored by pathogenic E. coli is not a hemolysin but a cytoplasmic enzyme leading to the overproduction of outer membrane vesicles (OMVs). Here, we showed that these specific OMVs inhibit the macroautophagic/autophagic flux by impairing the autophagosome-lysosome fusion, thus preventing the formation of acidic autolysosomes and autophagosome clearance. Furthermore, HlyF-associated OMVs were more prone to activate the non-canonical inflammasome pathway. Because autophagy and inflammation are crucial in the host’s response to infection especially during sepsis, our findings revealed an unsuspected role of OMVs in the crosstalk between bacteria and their host, highlighting the fact that these extracellular vesicles have exacerbated pathogenic properties.

Population genomics of the food-borne pathogen Vibrio fluvialis reveals lineage associated pathogenicity-related genetic elements.

Vibrio fluvialis is a food-borne pathogen with epidemic potential that causes cholera-like acute gastroenteritis and sometimes extraintestinal infections in humans. However, research on its genetic diversity and pathogenicity-related genetic elements based on whole genome sequences is lacking. In this study, we collected and sequenced 130 strains of V. fluvialis from 14 provinces of China, and also determined the susceptibility of 35 of the strains to 30 different antibiotics. Combined with 52 publicly available V. fluvialis genomes, we inferred the population structure and investigated the characteristics of pathogenicity-related factors. The V. fluvialis strains exhibited high levels of homologous recombination and were assigned to two major populations, VflPop1 and VflPop2, according to the different compositions of their gene pools. VflPop2 was subdivided into groups 2.1 and 2.2. Except for VflPop2.2, which consisted only of Asian strains, the strains in VflPop1 and VflPop2.1 were distributed in the Americas, Asia and Europe. Analysis of the pathogenicity potential of V. fluvialis showed that most of the identified virulence-related genes or gene clusters showed high prevalence in V. fluvialis , except for three mobile genetic elements: pBD146, ICEVflInd1 and MGIVflInd1, which were scattered in only a few strains. A total of 21 antimicrobial resistance genes were identified in the genomes of the 182 strains analysed in this study, and 19 (90%) of them were exclusively present in VflPop2. Notably, the tetracycline resistance-related gene tet(35) was present in 150 (95%) of the strains in VflPop2, and in only one (4%) strain in VflPop1, indicating it was population-specific. In total, 91% of the 35 selected strains showed resistance to cefazolin, indicating V. fluvialis has a high resistance rate to cefazolin. Among the 15 genomes that carried the previously reported drug resistance-related plasmid pBD146, 11 (73%) showed resistance to trimethoprim-sulfamethoxazole, which we inferred was related to the presence of the dfr6 gene in the plasmid. On the basis of the population genomics analysis, the genetic diversity, population structure and distribution of pathogenicity-related factors of V. fluvialis were delineated in this study. The results will provide further clues regarding the evolution and pathogenic mechanisms of V. fluvialis , and improve our knowledge for the prevention and control of this pathogen.

Vibrio albensis bacteremia: A case report and systematic review.

Vibrio species are gram-negative rods usually known to cause gastroenteritis and infrequently extraintestinal infections in humans. V. cholerae are classically associated with cholera epidemics, particularly serogroup O1 and serogroup O139. However, Vibrio albensis, a non-O1/ non-O-139 serogroup is rarely implicated in human infections. Thus, there is a paucity of data available on the pathogenic profile of V. albensis infections in humans and more research is needed to further delineate the clinical course and management. To fill this gap in the literature, we present the successful management of V. albensis bacteremia in a 64-year-old patient, and we conducted a systematic review of V. albensis infections reported to date, aiming to explore the clinical presentation, course, and management of V. albensis infections.