Molecular characterization of pathogenic Escherichia coli isolated from diarrheic and in-contact cattle and buffalo calves

Beta-lactamase-producing Escherichia coli in migratory geese at West Texas recreational parks

This study aimed to determine the prevalence, and the genomic characteristics of beta-lactamase-Resistant Escherichia coli isolated from the feces of migratory geese at one health interface in West Texas. A descriptive study was conducted. We collected geese feces (n = 165), water (n = 118), and soil (n = 74) from 22 recreational parks in West Texas. We used Chromogenic agar to isolate extended-spectrum beta-lactamase (ESBL)-Resistant-E. coli. We used the whole genome sequencing (WGS) method to determine the genomic characteristics of selected E. coli isolates. Among 357 samples, 12.61 % (95 %CI: 9.34-16.50) were positive for ESBL- Resistant-E. coli. From WGS of 20 E. coli isolates, 19 isolates harbored at least 1 beta-lactamase gene including blaCTX-M-1, blaCTX-M-65, blaCTX-M-14, blaCTX-M-15, blaCTX-M-27, blaCTX-M-55, blaCTX-M-32, blaTEM-1A, blaTEM-1B. Most of the isolates carried genes conferring resistance to tetracyclines-(tet(A), tet(B)), aminoglycosides-(aac(3)-IIa, aph(6)-Id, aph(3')-Ia, aadA1), sulfonamides-(sul1,sul2), amphenicol-(floR), trimethoprim-(dfrA1, dfrA14, dfrA17) and streptogramin-B(MLSB) agent-(mph(A)). 13 isolates showed chromosomal mutations in the promoter region G of the ampC beta-lactamase gene. We detected sixteen incompatibility plasmid groups and 60 virulence genes, which are related to adherence, exotoxin, invasion, and nutrition/metabolic factors. Genome analysis showed that all isolates were genetically similar to human E. coli isolates. The study showed that migratory geese at recreational parks can be reservoirs of resistant bacteria with diverse serotypes and sequence types of E. coli isolates. Based on the findings, the detection of a multidrug-resistant E. coli strain reinforces the importance of adequate hygiene practices for humans and pet animals after visiting recreational parks.

Molecular identification and antimicrobial resistance profiling of pathogenic E. coli isolates from smallholder livestock households in Central Ethiopia

Escherichia coli of different pathotypes are frequently involved in morbidity and mortality in animals and humans. The study aimed to identify E. coli pathotypes and determine antimicrobial resistance (AMR) profiles in Ethiopian smallholder livestock households. The pathotyping included 198 E. coli isolates identified from human and environmental samples collected from 98 households. AMR profiling was conducted on selected E. coli pathotypes from 89 households, along with known isolates from calf samples obtained from the same households. Morphological and biochemical tests were used to identify presumptive E. coli isolates. DNA was extracted and then singleplex PCR was used to amplify virulence genes. A disc diffusion test was applied for AMR profilings in E. coli pathotypes. Data were evaluated using chi-square tests and logistic regression. Calf (79.8 %) and human (73.7 %) samples were more likely to contain pathotypes (OR 3.2; 95 % CI: 1.7, 5.9; p=0.001 and OR 2.3; 95 % CI: 1.2, 4.1; p=0.008, respectively) than the environmental samples (55.6 %). ETEC (32.3 %) and STEC (15.2 %) were the most common pathotypes detected in the study samples. Out of the 176 isolates selected for AMR profiling, 85 % were resistant to at least one drug and 36 % were multi-drug resistant (MDR). The MDR isolates were found in 44 households, with 11 sharing identical pathotypes and resistance profiles among the different samples. Thus, E. coli strains were likely circulated among humans, animals, and the environment. This in turn calls for a One-health approach to improve antimicrobial usage standards and promote proper waste disposal practices.

Genomic and Drug Resistance Profile of Bovine Multidrug-Resistant Escherichia coli Isolated in Kazakhstan

While studying the prevalence and profile of antibiotic resistance among E. coli isolated from the feces of calves with signs of colibacillosis, a strain with a wide spectrum of drug resistance was isolated. Whole-genome sequencing, followed by bioinformatic processing and the annotation of genes of this strain, showed that the genome has a total length of 4,803,482 bp and contains 4986 genes, including 122 RNA genes. A total of 31% of the genes are functionally significant and represent 26 functional groups. Additionally, 55 antibiotic resistance genes were revealed. A phenotypic drug-resistance study was performed according to CASFM and CLSI guidelines, which showed that the investigated strain was resistant to eight antibacterial drugs of different classes, including colistin. This is the first report on the AMR profile of an E. coli isolate obtained from a sick calf with evidence of escherichiosis in Kazakhstan. The provided information on the genome will be valuable in studying the evolution and development of antibiotic-resistant forms of E. coli and increase our knowledge of pathogenicity. It may also be a source for future comparative studies of the virulence and drug resistance of E. coli isolates.

A Systematic Review and Meta-Analysis of the Detection of Shiga Toxin-Producing Escherichia coli in Cattle in China in the Past 10 Years

Shiga toxin-producing Escherichia coli (STEC) is a significant pathogen that can cause foodborne illnesses and pose a serious public health problem. To date, no systematic evaluation or meta-analysis of STEC carriage in Chinese cattle has been conducted. Therefore, we conducted a systematic review and meta-analysis to assess the prevalence of STEC in cattle in China over the past decade. We retrieved 1868 articles from 6 databases (PubMed, Web of Science, CNKI, Wanfang, VIP, and Baidu). Based on criteria such as sample source, isolation time, and species, we selected 39 studies (comprising 16,437 samples from 14 provinces) for systematic review and meta-analysis. The analysis results indicated that the pooled prevalence of E. coli in cattle during the selected time period was 6% (95% CI: 0.03-0.09). Subgroup analysis revealed variations in STEC positivity rates across different sectors. The highest positivity rate was observed in the slaughter and processing sector (12%, 95% CI: 0.03-0.17), followed by the retail sector (6%, 95% CI: 0.01-0.13), with the breeding sector showing the lowest rate (5%, 95% CI: 0.03-0.17). Among the regions studied, Shandong exhibited the highest pooled prevalence (15%, 95% CI: 0.01-0.30), followed by Hebei (12%, 95% CI: 0.00-0.30) and Hubei (11%, 95% CI: 0.03-0.09). These findings indicate an uneven distribution of STEC in cattle across China. Our systematic evaluation of data over the past decade provides insights into the prevalence of STEC in cattle in China. These findings may assist in the prevention and control of STEC in cattle in the country. We recommend conducting further epidemiological investigations and establishing comprehensive surveillance programs to identify risk factors associated with STEC in cattle, thereby enhancing prevention and control strategies.

Virulence genes and antibiotic susceptibility patterns of Escherichia coli isolated from nosocomial urinary tract infections in the northwest of Iran during 2022-2023: A cross-sectional study

Background and Aims

Urinary tract infections (UTIs) are prevalent among hospitalized patients, constituting the most frequent health-care infections. Uropathogenic Escherichia coli (UPEC) is leading causative agent of UTIs. The present study was aimed to examine the susceptibility of UPEC isolates obtained from nosocomial cases to antibiotics, as well as their biofilm formation capability and frequency of virulence genes.

Methods

A total of 100 UPEC isolates were collected from nosocomial UTIs at Imam Reza Hospitals in Tabriz, Iran, spanning from April 2022 to January 2023. The antimicrobial susceptibility patterns were evaluated using the disk diffusion method, along with the detection of broad-spectrum β-lactam enzymes (ESBLs) and carbapenemases. The ability of isolates to form biofilms was assessed using the microtiter-plate method, while the PCR method was employed to identify the presence of virulence genes.

Results

The highest resistance was observed toward piperacillin (82%), followed by aztreonam and ciprofloxacin (81%), while the lowest resistance was found against piperacillin/tazobactam (12%) and meropenem (9%). ESBLs were detected in 62% of the isolates. The microtiter-plate results revealed strong, moderate, and weak biofilm formation abilities in 32%, 33%, and 24% of the isolates, respectively. The most prevalent virulence gene was fimA (74%) followed by hlyF (68%), papA (44%), papC (32%), iroN (26%), and cnf (20%).

Conclusion

The elevated levels of resistance to multiple antimicrobial agents, coupled with the co-presence of virulence genes and biofilm formation abilities, contribute to the persistence of UPEC-related infections, particularly in hospitalized patients. These findings underscore the necessity of implementing an effective program to control nosocomial UTIs caused by UPEC in the healthcare centers.

Molecular characterization of common zoonotic protozoan parasites and bacteria causing diarrhea in dairy calves in Ningxia Hui Autonomous Region, China

Diarrhea caused by zoonotic pathogens is one of the most common diseases in dairy calves, threatening the health of young animals. Humans are also at risk, in particular children. To explore the pathogens causing diarrhea in dairy calves, the present study applied PCR-based sequencing tools to investigate the occurrence and molecular characteristics of three parasites (Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi) and three bacterial pathogens (Escherichia coli, Clostridium perfringens, and Salmonella spp.) in 343 fecal samples of diarrheic dairy calves from five farms in Lingwu County, Ningxia Hui Autonomous Region, China. The total positive rate of these pathogens in diarrheic dairy calves was 91.0% (312/343; 95% CI, 87.9-94.0), with C. perfringens (61.5%, 211/343; 95% CI, 56.3-66.7) being the dominant one. Co-infection with two to five pathogens was found in 67.3% (231/343; 95% CI, 62.4-72.3) of investigated samples. There were significant differences (p < 0.05) in the positive rates of Cryptosporidium spp. and diarrheagenic E. coli among farms, age groups, and seasons. Two Cryptosporidium species (C. parvum and C. bovis) and five gp60 subtypes of C. parvum (IIdA15G1, IIdA20G1, IIdA19G1, IIdA14G1, and a novel IIdA13G1) were identified. Two assemblages (assemblage E and zoonotic assemblage A) of G. duodenalis and six ITS genotypes of E. bieneusi (J, Henan-IV, EbpC, I, EbpA, and ESH-01) were observed. Four virulence genes (eaeA, stx1, stx2, and st) of diarrheagenic E. coli and one toxin type (type A) of C. perfringens were detected. Our study enriches our knowledge on the characteristics and zoonotic potential of diarrhea-related pathogens in dairy calves.

Whole genome sequence analysis reveals high genomic diversity and potential host-driven adaptations among multidrug-resistant Escherichia coli from pre-weaned dairy calves

Food-producing animals such as dairy cattle are potential reservoirs of antimicrobial resistance (AMR), with multidrug-resistant (MDR) organisms such as Escherichia coli observed in higher frequency in young calves compared to older cattle. In this study, we characterized the genomes of enteric MDR E. coli from pre-weaned dairy calves with and without diarrhea and evaluated the influence of host-level factors on genomic composition. Whole genome sequence comparative analysis of E. coli (n = 43) revealed substantial genomic diversity that primarily clustered by sequence type and was minimally driven by calf diarrheal disease status (healthy, diarrheic, or recovered), antimicrobial exposure, and dietary zinc supplementation. Diverse AMR genes (ARGs)-including extended-spectrum beta-lactamase genes and quinolone resistance determinants-were identified (n = 40), with unique sets of ARGs co-occurring in gene clusters with large AMR plasmids IncA/C2 and IncFIB(AP001918). Zinc supplementation was not significantly associated with the selection of individual ARGs in E. coli, however analysis of ARG and metal resistance gene pairs identified positive associations between certain aminoglycoside, beta-lactam, sulfonamide, and trimethoprim ARGs with acid, tellurium and mercury resistance genes. Although E. coli in this study lacked the typical virulence factors of diarrheagenic strains, virulence genes overlapping with those in major pathotypes were identified. Among the 103 virulence genes detected, the highest abundance and diversity of genes corresponded to iron acquisition (siderophores and heme uptake). Our findings indicate that the host-level factors evaluated in this study were not key drivers of genomic variability, but that certain accessory genes in enteric MDR E. coli may be enriched. Collectively, this work provides insight into the genomic diversity and host-microbe interface of MDR E. coli from pre-weaned dairy calves.

Molecular identification of the most frequent pathotypes of Escherichia coli in calves with diarrhoea in the Cajamarca region of Peru

Background

Colibacillosis caused by Escherichia coli causes significant economic losses in the livestock sector worldwide and is one of the calves' leading causes of diarrhea.

Aim

This study aimed to identify the most frequent E. coli molecularly pathotypes in calves with diarrhea in six provinces of the Cajamarca region in the northern highlands of Peru.

Methods

Twenty-eight herds of dairy cattle under a semi-intensive rearing system were evaluated; 95 samples were isolated from calves with diarrhea up to the first month of life, 62 males and 33 females, during the rainy season.

Results

The presence of virulence genes of E. coli strains was more prevalent in males; the astA (89.47%), st (83.15%), and f5 (57.89%) genes were more expressed, and the lt (17.89%) and stx2 (1.05%) genes were less expressed. The eae gene (21.05%) was more present in females.

Conclusion

When E. coli strains express virulence genes astA, st, and f5 and their atypical double, triple, and quadruple combination between different observed pathotypes, they give rise to the formation of several pathotypes by the horizontal transfer of virulence genes, which can cause colibacillosis processes in more virulent calves, which is one of the most important causes of diarrhea in calves in the region of Cajamarca, compromising the sanitary viability in the herds.

Escherichia coli Strains Isolated from American Bison (Bison bison) Showed Uncommon Virulent Gene Patterns and Antimicrobial Multi-Resistance

E. coli is considered one of the most important zoonotic pathogens worldwide. Highly virulent and antimicrobial-resistant strains of E. coli have been reported in recent years, making it essential to understand their ecological origins. In this study, we analyzed the characteristics of E. coli strains present in the natural population of American bison (Bison bison) in Mexico. We sampled 123 individuals and determined the presence of E. coli using standard bacteriological methods. The isolated strains were characterized using molecular techniques based on PCR. To evaluate the diversity of E. coli strains in this population, we analyzed 108 suggestive colonies from each fecal sample. From a total of 13,284 suggestive colonies, we isolated 33 E. coli strains that contained at least one virulence gene. The virotypes of these strains were highly varied, including strains with atypical patterns or combinations compared to classical pathotypes, such as the presence of escV, eae, bfpB, and ial genes in E. coli strain LMA-26-6-6, or stx2, eae, and ial genes in E. coli strain LMA-16-1-32. Genotype analysis of these strains revealed a previously undescribed phylogenetic group. Serotyping of all strains showed that serogroups O26 and O22 were the most abundant. Interestingly, strains belonging to these groups exhibited different patterns of virulence genes. Finally, the isolated E. coli strains demonstrated broad resistance to antimicrobials, including various beta-lactam antibiotics.

Metagenomic analysis for exploring the potential of Lactobacillus yoelii FYL1 to mitigate bacterial diarrhea and changes in the gut microbiota of juvenile yaks

Diarrhea in calves is a common disease that results in poor nutrient absorption, poor growth and early death which leads to productivity and economic losses. Therefore, it is important to explore the methods to reduce diarrhea in yak's calves. Efficacy of lactic acid bacteria (LAB) for improvement of bacterial diarrhea is well recognized. For this purpose, two different doses (107 CFU, 1011 CFU) of Lactobacillus yoelii FYL1 isolated from yaks were fed to juvenile yaks exposed to E. coli O78. After a trial period of ten days fresh feces and intestinal contents of the experimental yaks were collected and metagenomics sequencing was performed. It was found that feeding a high dose of Lactobacillus yoelii FYL1 decreased abundance of phylum Firmicutes in the E. coli O78 infected group whereas, it was high in animals fed low dose of Lactobacillu yoelii FYL1. Results also revealed that counts of bacteria from the family Oscillospiraceae, genus Synergistes and Megasphaera were higher in control group whereas, order Bifidobacteriales and family Bifidobacteriaceae were higher in infected group. It was observed that bacterial counts for Pseudoruminococcus were significantly (P < 0.05) higher in animals of group that were given high dose of Lactobacillus yoelii FYL1 (HLAB). Compared to infected group multiple beneficial bacterial genera such as Deinococus and Clostridium were found higher in the animals that were given a low dose of Lactobacillus yoelii FYL1 (LLAB). The abundance of pathogenic bacterial genera that included Parascardovia, Bacteroides and Methanobrevibacter was decreased (P < 0.05) in the lower dose treated group. The results of functional analysis revealed that animals of LLAB had a higher metabolism of terpenoids and polyketides compared to animals of infected group. Virus annotation also presented a significant inhibitory effect of LLAB on some viruses (P < 0.05). It was concluded that L. yoelii FYL1 had an improved effect on gut microbiota of young yaks infected with E. coli O78. This experiment contributes to establish the positive effects of LAB supplementation while treating diarrhea.

Molecular detection and patho-morphological study of enteric Escherichia coli pathotypes in diarrheic neonatal calves

To understand the pathology of natural cases of E. coli pathotypes infection in bovine calves, 45 cases of bovine calves, below one month of age, died due to enteritis were studied. Total seventeen cases (37.77%) turned positive for different pathotypes of E. coli by RT-PCR. Out of seventeen positive samples for E. coli, six cases (35.29%) were positive for eae gene, three cases (17.64%) for bfp gene and eight cases (47.05) for fimA gene of E. coli. Gross lesions in these cases showed pin-point to ecchymotic hemorrhages in the mucosa of jejunum, ileum and colon. The draining mesenteric lymph nodes were swollen, enlarged and showed cord -like structure. Histopathology of small intestine showed, villi lining cells were sloughed off, tips of villi capillary plexus were congested and hemorrhagic, and skipping lesions of microabscesses in the crypts of mucosa were observed. In the duodenum, necrosis of crypts and infiltration of mononuclear cells in the lamina propria and around Brunner's gland. In mesenteric lymph nodes the subscapular space were infiltrated with mononuclear cells with depletion of lymphoid follicles in cortical area. Peri-trabecular and medullary sinuses of mesenteric lymph nodes were necrosed.

Monitoring the genetic variation of some Escherichia coli strains in wild birds and cattle

To date, there is limited data about the genetic relationship of Escherichia coli between wild birds and cattle because these birds act as silent vectors for many zoonotic bacteria. This study aimed to elucidate the role of rooming wild birds in the vicinity of cattle farm in transmission of the same pathogenic E. coli variants, identifying their virulence, resistance traits and genetic similarities of fimH virulence gene. About 240 faecal/cloacal swabs were collected from both species and examined bacteriologically. Escherichia coli was yielded in 45.8% and 32.5%, respectively, of examined cattle and wild birds. The most prevalent detected E. coli serovar was O26. High tetracycline and chloramphenicol resistance were recorded; however, gentamycin and ciprofloxacin exhibited the highest sensitivity rates. Polymerase chain reaction (PCR) conserved genotypic resistance (tetA and blaCTX-M) and virulence attributes (fimH, stx1, eaeA and ompA) of E. coli isolates were discussed in detail. The fimH gene revealed 100% sequence similarity when comparing with different E. coli isolates globally and locally. Finally, a close genetic association of E. coli with both wild birds and cattle was detected, thus strengthening its role in the dissemination of the infection via environment. Prevention and conservative policy should be carried as E. coli constitute enormous significant zoonotic risks to livestock and animal workers. Also, further studies to the whole genome sequencing of fimH, other virulence and resistance genes of E. coli are recommended trying to limit the possibilities of co-infection and transfer among different species.Contribution: The current study recorded updated data about the critical infectious role of wild birds to livestock, including cattle farms in Egypt. It also delivered some recommendations for good hygienic practices in cattle farms which must be implemented for handling animal manure.

Characterization of an Escherichia coli Isolate Coharboring the Virulence Gene astA and Tigecycline Resistance Gene tet(X4) from a Dead Piglet

tet(X4) is the critical resistance gene for tigecycline degradation that has been continually reported in recent years. In particular, pathogenic bacteria carrying tet(X4) are a severe threat to human health. However, information describing Escherichia coli coharboring tet(X4) with virulence genes is limited. Here, we isolated an E. coli strain coharboring tet(X4) and the heat-stable toxin gene astA from a dead piglet. The strain named 812A1-131 belongs to ST10. The genome was sequenced using the Nanopore and Illumina platforms. The virulence genes astA and tet(X4) are located on the chromosome and in the IncHI1-type plasmid p812A1-tetX4-193K, respectively. The plasmid could be conjugatively transferred to recipient E. coli J53 with high frequency. In vivo experiments showed that strain 812A1-131 is pathogenic to Galleria mellonella and could colonize the intestines of mice. In summary, pathogenic E. coli could receive a plasmid harboring the tet(X4) gene, which can increase the difficulty of treatment. The prevalence and transmission mechanisms of pathogenic bacteria coharboring the tet(X4) gene need more attention.

Occurrence of Escherichia coli Pathotypes in Diarrheic Calves in a Low-Income Setting

Different E. coli pathotypes are common zoonotic agents. Some of these pathotypes cause recurrent and widespread calf diarrhea and contribute to significant economic losses in the livestock sector worldwide in addition to putting humans at risk. Here, we investigated the occurrence of E. coli pathotypes in diarrheic calves in Ethiopia kept under various calf management practices. One hundred fecal samples were collected from diarrheic calves in 98 different farms. E. coli was isolated in the samples from 99 of the diarrheic calves, and virulence genes were detected in 80% of the samples. The occurrence of E. coli pathotypes in the samples was 32% ETEC, 23% STEC, 18% STEC/ETEC, 3% EPEC, 2% EAEC, and 1% EHEC. No diarrheic calves were positive for the EIEC and DAEC pathotypes. The occurrence of pathotypes was positively associated with female calves (EPEC, p = 0.006), aged less than 2 weeks (STEC, p = 0.059), and calves fed colostrum via the hand method (STEC, p = 0.008 and EAEC, p = 0.003). This study revealed that several E. coli pathotypes occurred among calves affected with diarrhea. Moreover, the presence of a mixed STEC/ETEC pathotypes infection was present in the studied low-income setting. These findings indicate a considerable risk for the zoonotic transmission from calves to humans and the options to provide the better management for younger calves in order to reduce the economic loss.

Molecular identification of diarrheagenic Escherichia coli pathotypes and their antibiotic resistance patterns among diarrheic children and in contact calves in Bahir Dar city, Northwest Ethiopia

Diarrheagenic Escherichia coli strains are an essential cause of diarrheal infection in younger children and animals. The study was focused on understanding the associated characteristics of various DEC strains among children and calves, establishing the possible zoonotic transmission, and determining their antibiotic resistance patterns. Samples from 144 acute diarrheic children and 50 diarrheic calves were collected and processed using traditional culture methods. The molecular identification of pathotypes was completed using primer-specific polymerase chain reaction (PCR) targeting ten virulence genes (stx1, stx2, eae, aatA, lt, st, ial, hlyA bfpA, and daaE) related to six DEC pathotypes (EPEC, ETEC, EHEC, EAEC EIEC, and DAEC). The antimicrobial susceptibility testing was carried out using the Kirby-Bauer disk diffusion method. Colonies from 74 study subjects (54 diarrheic children and 20 diarrheic calves) were positive for E. coli isolates. Subsequent PCR detection discovered that 77% of children and 85% of calves' isolates were positive for one or more virulence genes typical of particular strains. Among those ETEC [(18%), (26%)] is being the maximum predominant, and [(15%), (15%)] were positive for STEC, [(13%), (8%)] for atypical EPEC, [(6%), (7%)] for EHEC, [(6%), (5%)] for EAEC, and [(6%), (4%)] for EIEC strains in children's and calves, respectively. Of the identified E. coli isolates, about 29% were found to be hybrid isolates. ETEC (66.7%) and STEC (58.9%) strains showed a better detection rate in contact children with diarrheic calves than children with no contacts. Most antibiotic resistances were obtained towards amoxicillin (64.9%), gentamycin (56.8%), and ampicillin (54.1%). Up to sixty-five percent of isolates were resistant to a minimum of three categories of antibiotics. This is the primary report on the wide occurrence of the six-diarrheagenic Escherichia coli strains, and ETEC was found to be the predominant pathotype among children and contact calves in Ethiopia.

Determination of anti-phage antibodies in calf sera following application of Escherichia coli and Mannheimia haemolytica-specific bacteriophages

Introduction

The widespread occurrence of drug-resistant bacteria has increased interest in alternatives to antibiotics for combatting bacterial infections, among which bacteriophages play an important role. The ability of phage proteins to induce an anti-phage immune response can significantly limit the effectiveness of treatment, which was the basis for the study described in this article. The aim of the study was to assess the effects of bacteriophages on the induction of an anti-phage humoral response in calves.

Material and Methods

The study was conducted using phage components of experimental preparations and sera from calves treated and not treated with phages. Levels of G, M and A immunoglobulins were analysed by ELISA. The assay plates were coated with whole Escherichia coli and Mannheimia haemolytica phages and selected phage proteins obtained in sodium dodecyl sulphate-polyacrylamide gel electrophoresis and two-dimensional electrophoresis. Neutralisation of phages by immunoglobulins was assessed by determining phage titres using double-layer plates.

Results

The results confirmed an increased anti-phage response affecting all immunoglobulin classes in the calf sera. The highest significant (P ≤ 0.05) level of antibodies was observed for IgG in the sera of calves receiving phages. The phage neutralisation test showed a significant differences (P ≤ 0.05) in the reduction of phage titres in comparison to untreated calves.

Conclusion

Despite the induction of an anti-phage response, no significant negative effect on the antibacterial activity of phages was observed in vitro.

The role of Musca domestica and milk in transmitting pathogenic multidrug-resistant Escherichia coli and associated phylogroups to neonatal calves

Escherichia coli, as a global source of antimicrobial resistance, is a serious veterinary and public health concern. The transmission of pathogenic multidrug-resistant (MDR) E. coli within diarrheic calves and its correlation with Musca domestica and milk strains have been investigated. In total, 110, 80, and 26 E. coli strains were obtained from 70 rectal swabs from diarrheic calves, 60 milk samples and 20 M. domestica, respectively. Molecular pathotyping of E. coli revealed the presence of pathogenic E. coli with a higher percentage of shigatoxigenic strains within diarrheic calves and M. domestica at 46.4% and 34.6%, respectively. Phenotypic antimicrobial resistance revealed higher β-lactams resistance except for cefquinome that exhibited low resistance in M.domestica and milk strains at 30.8% and 30%, respectively. The extended-spectrum cephalosporin (ESC) resistant strains were detected within fecal, M. domestica, and milk strains at 69.1%, 73.1%, and 71.3%, respectively. All E. coli strains isolated from M. domestica exhibited MDR, while fecal and milk strains were harboring MDR at 99.1% and 85%, respectively. Molecular detection of resistant genes revealed the predominance of the bla_TEM gene, while none of these strains harbored the bla_OXA gene. The highest percentages for bla_CTXM and bla_CMYII genes were detected in M. domestica strains at 53.8% and 61.5%, respectively. Regarding colistin resistance, the mcr-1 gene was detected only in fecal and milk strains at 35.5% and 15%, respectively. A high frequency of phylogroup B2 was detected within fecal and M. domestica strains, while milk strains were mainly assigned to the B1 phylogroup. Pathogenic E. coli strains with the same phenotypic and genotypic antimicrobial resistance and phylogroups were identified for both diarrheic calves and M. domestica, suggesting that the possible role of M. domestica in disseminating pathogenic strains and antimicrobial resistance in dairy farms.

Bacterial Causes of Intestinal Disease in Dairy Calves: Acceptable Control Measures

Although diarrhea in dairy calves is common, it is not always due to bacteria. Escherichia coli, Salmonella, and Clostridium perfringens are the most commonly implicated bacteria, but an etiologic diagnosis should be sought before specific treatment is instituted. Nonspecific treatment such as fluid, electrolyte, and nutritional support should be accomplished while diagnostics are pending. Antimicrobials should not be a first-line therapy for calf diarrhea. Control measures are discussed.

Literature Review: Coinfection in Young Ruminant Livestock-Cryptosporidium spp. and Its Companions

The protozoan Cryptosporidium parvum is one of the major causative pathogens of diarrhoea in young ruminants; therefore, it causes economic losses and impairs animal welfare. Besides C. parvum, there are many other non-infectious and infectious factors, such as rotavirus, Escherichia coli, and Giardia duodenalis, which may lead to diarrhoeic disease in young livestock. Often, more than one infectious agent is detected in affected animals. Little is known about the interactions bet-ween simultaneously occurring pathogens and their potential effects on the course of disease. In this review, a brief overview about pathogens associated with diarrhoea in young ruminants is presented. Furthermore, information about coinfections involving Cryptosporidium is provided.

Molecular characterization of enterohemorrhagic Escherichia coli isolated from diarrhea samples from human, livestock, and ground beef in North Jordan

Background and Aim:

Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen with worldwide distribution. Data regarding its presence, distribution, virulence, and antimicrobial susceptibility among various animal species and humans in Jordan are lacking. Therefore, the objectives of this study were to isolate and characterize EHEC from human and animal diarrhea fecal samples and ground beef samples.

Materials and Methods:

A total of 100 and 270 diarrhea fecal samples from humans and animals, respectively, were collected. In addition, 40 ground beef meat samples were collected from retail markets. EHEC was positively identified by detecting Shiga toxins (stx1 and stx2) genes using multiplex polymerase chain reaction (PCR). Antimicrobial susceptibility patterns were determined using the disk diffusion test. Beta-lactamase production was detected using the double disk diffusion test and the extended-spectrum beta-lactamases (ESBLs) were identified by detection of bla_TEM, bla_SHV, and OXA-1 genes using multiplex PCR. Pulsed-field gel electrophoresis (PFGE) was used to investigate the relatedness of EHEC isolates from different sources.

Results:

Out of 410 samples, 194 E. coli isolates were positively identified, of which 57 isolates (29%) were classified as EHEC. Thirty-five (61%) of EHEC isolates were serotyped as O157 (19: O157:H7 and 16: O157:NM). The stx1 gene was detected only among the sheep and goats isolates at a rate of 7.6% and 5.2%, respectively, while the stx2 gene was detected in only one ground beef meat sample. EHEC isolates showed high resistance patterns against amoxicillin, gentamycin, cephalexin, and doxycycline. Twenty-four out of 32 EHEC isolates were determined as ESBL producers, among which 14 isolates expressed the bla_SHVgene and 19 isolates expressed the bla_TEM while four expressed both genes. PFGE analysis revealed two clusters with high similarity (92%) originated from ground beef meat and cattle fecal samples. No similarities were found between human and animal E. coli isolates.

Conclusion:

Results of this study indicate widespread ESBL EHEC among humans, animals, and ground beef meat samples. These results represent an important alarm that requires the implementation of appropriate preventative measures by both human and animal health sectors to prevent the transmission of this important foodborne pathogen.

Pathotyping and antimicrobial susceptibility testing of Escherichia coli isolates from neonatal calves

Neonatal calf mortality is a major concern to livestock sector worldwide. Neonatal calf diarrhoea (NCD), an acute severe condition causes morbidity and mortality in calves. Amongst various pathogens involved in NCD, E. coli is considered as one of the major causes. The study was targeted to characterize E. coli isolates from neonatal calves for diarrhoeagenic Escherichia coli (DEC) types (pathotyping), antimicrobial resistance (AMR) profiling and to correlate with epidemiological parameters. From neonates, a total of 113 faecal samples were collected, out of that 308, lactose fermenting colonies were confirmed as E. coli. Pathotypable isolates (12.3%) were represented by STEC (6.1%), EPEC (2.9%), ETEC (1.9%), EAEC (0.9%) and EHEC (0.3%). Occurrence of STEC was more in non-diarrhoeic calves, whereas ETEC was observed more in diarrhoeic calves. EPEC occurrence was observed in both diarrhoeic and non-diarrhoeic calves. Fishers extract test showed no significant association for occurrence of DEC types to type of dairies, health status, species, breed, age and sex of neonatal calves. Two hundred and eighty isolates were tested for antimicrobial susceptibility. The isolates showed maximum resistance towards ampicillin (55.4%) followed by tetracycline (54.3%), while minimum resistance was observed towards meropenem (2.5%). Multidrug resistant E. coli isolates were found to be 139 (49.6%), and Extended-spectrum beta-lactamase (ESBL) producers were 120 (42.9%). DEC pathotypes like STEC, ETEC, EHEC and EAEC that are also multidrug resistant present in neonatal calves have zoonotic potential and hence are of public health significance.

Molecular characterization of Escherichia coli isolated from milk samples with regard to virulence factors and antibiotic resistance

BACKGROUND AND AIM

Raw milk is considered an essential source of nutrition during all stages of human life because it offers a valuable supply of protein and minerals. Importantly, milk is considered a good media for the growth and contamination of many pathogenic bacteria, especially food-borne pathogens such as Escherichia coli. Thus, the objective of this study was to characterize E. coli and detect its virulence factors and antibiotic resistance from raw milk samples.

MATERIALS AND METHODS

Raw milk samples (n=100) were collected from different localities in Qena, Egypt, and investigated for the presence of E. coli using different biochemical tests, IMViC tests, serotyping to detect somatic antigen type, and molecularly by polymerase chain reaction (PCR) tests. The presence of different virulence and antimicrobial genes (hly, eae, stx1, stx2, blaTEM, tetA(A), and tetB genes) in E. coli isolates was evaluated using PCR.

RESULTS

The results demonstrated that 10 out of 100 milk samples were contaminated with E. coli. Depending on serology, the isolates were classified as O114 (one isolate), O27 (two isolates), O111 (one isolate), O125 (two isolates), and untypeable (five isolates) E. coli. The sequencing of partially amplified 16S rRNA of the untypeable isolates resulted in one isolate, which was initially misidentified as untypeable E. coli but later proved as Enterobacter hormaechei. Moreover, antibacterial susceptibility analysis revealed that nearly all isolates were resistant to more than 3 families of antibiotics, particularly to b-lactams, clindamycin, and rifampin. PCR results demonstrated that all E. coli isolates showed an accurate amplicon for the blaTEM and tetA(A) genes, four isolates harbored eae gene, other four harbored tetB gene, and only one isolate exhibited a positive stx2 gene.

CONCLUSION

Our study explored vital methods for identifying E. coli as a harmful pathogen of raw milk using 16S rRNA sequencing, phylogenetic analysis, and detection of virulence factors and antibiotic-resistant genes.

Detection of novel sequence types and zoonotic transmission potentiality among strains of Shiga toxigenic Escherichia coli (STEC) from dairy calves, animal handlers and associated environments

Shiga toxigenic Escherichia coli (STEC) is one of the most important food-borne zoonotic bacterial pathogens responsible for causing gastrointestinal infections, haemorrhagic colitis and haemolytic uremic syndrome. The present study was aimed to isolate and characterize STEC from neonatal dairy calves, animal handlers and their surrounding environment and to establish the genetic relationship among isolates by multilocus sequence typing (MLST). A total number of 115 samples were collected and processed for the isolation of E. coli. The occurrence rate of E. coli was 92.2% (106/115), of which, 18 were typed as STEC. Antibacterial susceptibility analysis revealed 11 (61.1%) strains as multiple drug-resistant (MDR). MLST analysis has delineated 16 sequence types (STs) including nine novel STs. Among STs, ST58 dominated with three strains and was recovered from the environment and neonatal calves. Strains from neonatal calves and humans showed genetic relatedness with significant bootstrap support values indicative of zoonotic transmission potentiality. Analysis of 211 global isolates belonging to 61 STs indicated predominant STs (ST 21, ST 33 and ST 3416) that can be either host-specific (ST 33 and ST 3416) or can be shared among human and bovine hosts (ST 21). The MLST analysis indicates genetic relatedness among isolates and the results predispose inter-host transmission and zoonotic spread.