Regional variation in the prevalence of E. coli O157 in cattle: a meta-analysis and meta-regression

Sample Type and Processing Plant Differences in the Proportion of Enterohemorrhagic Escherichia coli O157 and Non-O157 Serogroups in Feces and on Hides of Cull Dairy Cattle at Slaughter

The study was conducted to determine the proportion and concentration of enterohemorrhagic Escherichia coli (EHEC) O157 and six non-O157 (O26, O45, O103, O111, O121, and O145) serogroups and identify seasonal and processing plant differences in feces and on hides of cull dairy cattle processed in commercial slaughterhouses in the United States. Approximately 60 rectal and 60 hide-on samples from matched carcasses were collected in each of three processing plants, in two periods; summer of 2017 and spring of 2018. Samples before enrichment were spiral plated to quantify EHEC, and postenriched samples underwent culture methods that included immuno-magnetic separation, plating on selective media, and PCR assays for identification and serogroup confirmation of putative isolates. An isolate was considered EHEC O157 positive if it harbored serogroup-specific (rfbE), Shiga toxin (stx1 and/or stx2), and intimin (eae) genes and EHEC non-O157 positive if at least one of the non-O157 serogroup-specific, stx1 and/or stx2, and eae genes was identified. Generalized linear mixed models were fitted to estimate overall proportion of positives for EHEC O157 and non-O157 EHEC serogroups, as well as seasonal and processing plant differences in fecal and hide-on proportion of positives. The fecal EHEC proportion at the sample level was 1.8% (95% CI = 0.0-92.2%) and 4.2% (95% CI = 0.0-100.0%) for EHEC O157 and EHEC non-O157, respectively. Hide sample level proportion of positives was 3.0% (95% CI = 0.0-99.9%) for EHEC O157 and 1.6% (95% CI = 0.0-100.0%) for EHEC non-O157. The proportion of EHEC O157 and non-O157 significantly differed by processing plant and sample type (hide vs. feces), but not by season. The association between proportion of EHEC serogroups in feces with the proportion on hides collected from matched cattle was 7.8% (95% CI = 0.6-53.3%) and 3.8% (95% CI = 0.3-30.8%) for EHEC O157 and non-O157, respectively. Taken together, our findings provide evidence of a low proportion of EHEC serogroups in the feces and on hides of cull dairy cattle and that their proportion varies across processing plants.

Assessment of knowledge, attitude and practices (KAP) of farmers about transmission of zoonotic diseases in Ada'a district, Oromia, Ethiopia

In developing countries like Ethiopia, zoonotic diseases pose a significant health and economic burden, with high exposure of farmers to zoonotic infection given the prevailing traditional husbandry practices. A cross-sectional survey involving 388 farmers in the Ada'a district central Ethiopia was conducted to investigate their knowledge, attitudes, and practices (KAP) regarding the transmission of zoonotic diseases. The respondents' mean age was 41.0 ± 10.0 SD years. The majority of respondents (39.4%) were between the ages of 41 and 50, and 90.0% were married. Farmers claimed that conversations with family, colleagues, and friends were the primary sources of zoonoses information. Farmers stated that the primary sources of information on zoonotic diseases as community. They had a relatively low level (66.8%) of knowledge on zoonotic diseases and half of them (54.9%) did not have good information on zoonoses. Three-quarters (75.2%) of the farmers reported that they neither consume meat and milk nor use offal and hide/skin from sick or dead animals. Similarly, 71.1% of them stated that they do not eat meat from regularly aborting sheep/goats, and never consume raw meat and milk. Most of the respondents correctly answered that raw meat (82.7%) and raw milk (79.9%) are means of disease transmission from animals to humans. However, considerable proportions of them were unaware of zoonotic transmission of bovine tuberculosis (61.3%) and brucellosis (74.7%) transmission through raw milk intakes, and risk of taeniasis (71%) due to raw meat consumption. But, considerable proportions had never dewormed (48.7%), or tested their animals for brucellosis (82.7%) and bovine tuberculosis (83.3%), and more than three quarters (77.3%) did not used personal protective equipment when handling sick animals. Farmers who had a secondary education or above (OR = 6.8, CI = 2.4-18.0, p = 0.004), aged between 41 and 50 years (OR = 3.0, 95% CI: 1.2-7.2, p = 0.015), and those having good knowledge (OR = 2.1, CI = 1.3-3.5, p = 0.002), and positive attitude related to zoonotic diseases (OR = 7.8, CI = 4.7-12.9, p < 0.001) had better practices that reduce the risk of exposure to zoonotic infections than their counterparts. This study revealed a knowledge gaps, a low level of the desired attitude, and high-risk behavioral practices which call for awareness creation about zoonotic disease transmission.

Prevalence, Seroprevalence and Risk Factors of Avian Influenza in Wild Bird Populations in Korea: A Systematic Review and Meta-Analysis

Since the first recorded outbreak of the highly pathogenic avian influenza (HPAI) virus (H5N1) in South Korea in 2003, numerous sporadic outbreaks have occurred in South Korean duck and chicken farms, all of which have been attributed to avian influenza transmission from migratory wild birds. A thorough investigation of the prevalence and seroprevalence of avian influenza viruses (AIVs) in wild birds is critical for assessing the exposure risk and for directing strong and effective regulatory measures to counteract the spread of AIVs among wild birds, poultry, and humans. In this study, we performed a systematic review and meta-analysis, following the PRISMA guidelines, to generate a quantitative estimate of the prevalence and seroprevalence of AIVs in wild birds in South Korea. An extensive search of eligible studies was performed through electronic databases and 853 records were identified, of which, 49 fulfilled the inclusion criteria. The pooled prevalence and seroprevalence were estimated to be 1.57% (95% CI: 0.98, 2.51) and 15.91% (95% CI: 5.89, 36.38), respectively. The highest prevalence and seroprevalence rates were detected in the Anseriformes species, highlighting the critical role of this bird species in the dissemination of AIVs in South Korea. Furthermore, the results of the subgroup analysis also revealed that the AIV seroprevalence in wild birds varies depending on the detection rate, sample size, and sampling season. The findings of this study demonstrate the necessity of strengthening the surveillance for AIV in wild birds and implementing strong measures to curb the spread of AIV from wild birds to the poultry population.

A systematic review and meta-analysis of published literature on prevalence of non-O157 Shiga toxin-producing Escherichia coli serogroups (O26, O45, O103, O111, O121, and O145) and virulence genes in feces, hides, and carcasses of pre- and peri-harvest cattle worldwide

OBJECTIVE

The objective of this study was to summarize peer-reviewed literature on the prevalence and concentration of non-O157 STEC (O26, O45, O103, O111, O121, and O145) serogroups and virulence genes (stx and eae) in fecal, hide, and carcass samples in pre- and peri-harvest cattle worldwide, using a systematic review of the literature and meta-analyses.

DATA SYNTHESIS

Seventy articles were eligible for meta-analysis inclusion; data from 65 articles were subjected to random-effects meta-analysis models to yield fecal prevalence estimates. Meta-regression models were built to explore variables contributing to the between-study heterogeneity.

RESULTS

Worldwide pooled non-O157 serogroup, STEC, and EHEC fecal prevalence estimates (95% confidence interval) were 4.7% (3.4-6.3%), 0.7% (0.5-0.8%), and 1.0% (0.8-1.1%), respectively. Fecal prevalence estimates significantly differed by geographic region (P < 0.01) for each outcome classification. Meta-regression analyses identified region, cattle type, and specimen type as factors that contribute to heterogeneity for worldwide fecal prevalence estimates.

CONCLUSIONS

The prevalence of these global foodborne pathogens in the cattle reservoir is widespread and highly variable by region. The scarcity of prevalence and concentration data for hide and carcass matrices identifies a large data gap in the literature as these are the closest proxies for potential beef contamination at harvest.

Prevalence and Antimicrobial Resistance Profiles of Foodborne Pathogens Isolated from Dairy Cattle and Poultry Manure Amended Farms in Northeastern Ohio, the United States

Foodborne pathogens significantly impact public health globally. Excessive antimicrobial use plays a significant role in the development of the public health crisis of antibiotic resistance. Here, we determined the prevalence and antimicrobial resistance profiles of E. coli O157, Salmonella, L. monocytogenes, and Campylobacter isolated between 2016 and 2020 from small scale agricultural settings that were amended with dairy cattle or poultry manure in Northeastern Ohio. The total prevalence of the foodborne pathogens was 19.3%: Campylobacter 8%, Listeria monocytogenes 7.9%, Escherichia coli O157 1.8%, and Salmonella 1.5%. The prevalence was significantly higher in dairy cattle (87.7%) compared to poultry (12.2%) manure amended farms. Furthermore, the prevalence was higher in manure samples (84%) compared to soil samples (15.9%; p < 0.05). Multiple drug resistance was observed in 73%, 77%, 100%, and 57.3% of E. coli O157, Salmonella, L. monocytogenes, and Campylobacter isolates recovered, respectively. The most frequently observed resistance genes were mphA, aadA, and aphA1 in E. coli O157; blaTEM, tet(B), and strA in Salmonella; penA, ampC, lde, ermB, tet(O), and aadB in L. monocytogenes and blaOXA-61, tet(O), and aadE in Campylobacter. Our results highlight the critical need to address the dissemination of foodborne pathogens and antibiotic resistance in agricultural settings.

Etiopathological and hematobiochemical profiles in goats with gastrointestinal disorders

Background and Aim

Gastrointestinal (GI) disorders in small ruminants limit production efficiency and productivity growth in the livestock sector, thereby directly preventing farmers from augmenting their income. This study aimed to provide detailed insight into the etiology, hematobiochemical parameters, and epidemiological risk factors of GI disorders in goats and to determine the pathology associated with the disorders.

Materials and Methods

Over the period of 2018-2019, 500 goats in and around Bhubaneswar, Odisha, India, were screened for GI disorders based on clinical signs. Blood samples from the control (n=10) and treatment (n=25) groups were collected for both hematological and serum biochemical alterations. Fecal examinations (n=220) were conducted for parasitic, bacterial, and virological assessments. Detailed necropsy and histopathological evaluations were conducted on 27 goats.

Results

The GI disorder prevalence rate and mortality rate among the 500 goats analyzed were 44.4% and 12.27%, respectively. Chi-square analysis showed a significantly higher occurrence of GI disorders among the goats that were between 6 months and 1.5 years old (58.72%), were of the Ganjam breed (45.49%), had a poor body condition (71.11%), and were housed with an earthen floor (55.22%). The most common etiological risk factor observed was parasitic infection (65.45%), followed by bacterial (18.18%) and mixed infection (9.54%). Blood analysis showed neutrophilia and eosinophilia in infected goats, in addition to anemia; significant decreases in total protein, globulin, albumin, and glucose levels; and significant increases in aspartate transaminase and alanine aminotransferase levels. The major histopathological findings were infiltration of mononuclear cells and desquamation of the intestinal and ruminal mucosa.

Conclusion

Stakeholders should focus not only on parasitic infections and other important etiological risk factors for GI disorders in goats but also on proper farming management practices to help enhance the income of farmers. The hematobiochemical alterations and pathomorphological changes reported in this study can be used by field veterinarians as guidelines for clinical evaluation and disease severity assessment.

Assessment of beef carcass contamination with Salmonella and E. coli O 157 in slaughterhouses in Bishoftu, Ethiopia

Background

Salmonella and E. coli O157 are common causes of foodborne diseases. Evisceration and de-hiding steps can lead to carcass contamination during slaughter operation. In Ethiopia, information on the association between the presence of these pathogens in the rectal content and/or on the hide of cattle and their presence on the carcass is lacking.

Methods

The aim of this study was to assess the sources of beef carcass contamination with Salmonella and E. coli O157 during slaughter. Rectal contents and hide- and carcass-swabs (from three sites: foreleg, brisket and hind leg) were collected from 70 beef cattle at two small scale slaughterhouses. Isolates were genotyped by the Pulsed Field Gel Electrophoresis method and tested for resistance against 14 microbial drugs.

Results

Salmonella was detected at equal proportions (7.1%) in rectal content samples and hide swabs. E. coli O157 was detected in 8.6% of the rectal contents and 4.3% of the hide swabs. The proportion of contaminated carcasses was 8.6% for Salmonella and 7.1% for E. coli O157. Genetic linkage between the Salmonella and E. coli O157 isolates from the rectal contents and/or hides and carcasses were observed only in a few cases (2 and 1 carcasses, respectively) indicating the limited direct transfer of the pathogens from the feces and/or hide to the carcass during slaughter. Most carcasses became positive by cross contamination. All the S. Typhimurium isolates (n = 8) were multidrug resistant being resistant to ampicillin, chloramphenicol, sulfamethoxazole and tetracycline. The two S. Dublin isolates were resistant to colistin. All E. coli O157 isolates were susceptible to the antimicrobials tested.

Conclusion

The results indicated that cross contamination may be an important source for carcass contamination.

Assessment of Hygienic Practices in Beef Cattle Slaughterhouses and Retail Shops in Bishoftu, Ethiopia: Implications for Public Health

Understanding the potential drivers of microbial meat contamination along the entire meat supply chain is needed to identify targets for interventions to reduce the number of meatborne bacterial outbreaks. We assessed the hygienic practices in cattle slaughterhouses (28 employees) and retail shops (127 employees) through face-to-face interviews and direct personal observations. At the slaughterhouses, stunning, de-hiding and evisceration in vertical position, carcass washing and separate storage of offal were the identified good practices. Lack of hot water baths, absence of a chilling room, infrequent hand washing, insufficiently trained staff and irregular medical check-up were practices that lead to unhygienic handling of carcasses. At the retail shops, cleaning equipment using soap and hot water (81%), storing unsold meat in refrigerators (92%), concrete floors and white painted walls and ceilings were good practices. Adjacently displaying offal and meat (39%), lack of a cold chain, wrapping meat with plastic bags and newspapers, using a plastic or wooden cutting board (57%), infrequent washing of equipment and floors, and inadequately trained employees were practices that could result in unhygienic handling of beef. Our study identified unhygienic practices both at the slaughterhouses and retail shops that can predispose the public to meatborne infections, which could be improved through training and implementation of quality control systems.

Occurrence of Multi-Drug Resistant Escherichia Coli and Escherichia Coli O157:H7 in Meat and Swab Samples of Various Contact Surfaces at Abattoir and Butcher Shops in Jimma Town, Southwest District of Ethiopia

Background

Raw meat is one of the commonly consumed traditional diets in Ethiopia. However, unhygienic processing and distribution practices are risky for contamination of meat leading to human infection. This study was conducted to assess the presence of multi-drug resistant E. coli with special emphasis on E. coli O157:H7 from meat of cattle and swab samples at abattoir houses and butcher shops in Jimma town, Southwest district of Ethiopia.

Methodology

A cross-sectional descriptive study was conducted from April to July, 2018. The isolation and identification processes passed through enrichment of samples with modified tryptone soy broth (mTSB), streaked onto MacConkey agar and Cefixime-tellurite sorbitol MacConkey agar, biochemical testing (indole and TSI), followed by latex agglutination testing.

Results

Out of 505 samples, 102 (20.2%) and 27 (5.4%) were positive for E. coli and E. coli O157:H7, respectively. Of these, 55 (19.3%) and 47 (21.4%) of E. coli and 17 (6.0%) and 10 (4.5%) of E. coli O157:H7 were isolated from the abattoir and butcher shop samples, respectively. A significant difference in the occurrences was observed among sample sources. Antimicrobial susceptibility test results showed that, 92.2% to 96.1% of E. coli and 85.5% to 96.3% of E. coli O157:H7 were susceptible to third generation cephalosporin, ciprofloxacin, gentamycin, kanamycin, streptomycin, and chloramphenicol. About 91.2% and 97.1% of E. coli and 88.9% and 92.6% of E. coli 0157:H7 were resistant to ampicillin and erythromycin, respectively. A total of 57 (44.2%) E. coli and E. coli O157:H7 isolates were resistant to three or more classes of antibiotics. All abattoir and butcher shop workers did not have any formal education or training certificates on food safety, and unhygienic practices were also observed.

Conclusion

The presence of E. coli and E. coli O157:H7 including multi-drug resistant isolates in raw meat highlights how the current meat processing and distribution practice was unhygienic. Therefore, strategies in the prevention and control of food-borne infections that could be caused by multi-drug resistant strains will depend greatly on hygienic processing and distribution practices of meat.

Occurrence, Molecular Characteristics, and Antimicrobial Resistance of Escherichia coli O157 in Cattle, Beef, and Humans in Bishoftu Town, Central Ethiopia

Escherichia coli O157 is a Shiga toxin-producing E. coli causing disease in humans. Cattle are the primary reservoir of the pathogen. Information regarding the contribution of cattle to diarrheal illnesses in humans through consumption of contaminated beef is scarce in Ethiopia. We collected samples from 240 cattle, 127 beef, and 216 diarrheic patients in Bishoftu town in Ethiopia to assess the occurrence and determine the virulence genes, genetic relatedness, and antimicrobial resistance of E. coli O157. E. coli O157 was detected in 7.1% of the rectal content samples from cattle in slaughterhouses, in 6.3% (n = 127) of the beef samples, and in 2.8% of the diarrheic patients' stool samples. All isolates were positive for eae gene, 24 (77%) of them were positive for stx2 gene (21 stx2c and 3 stx2a), whereas stx1 gene was not detected. Molecular typing grouped the isolates into eight pulsed-field gel electrophoresis pulsotypes with three pulsotypes containing isolates from all three sources, one pulsotype containing one isolate from human origin and one isolate from beef. The remaining four pulsotypes contained isolates unique either to beef or to humans. With the exception of 1 multidrug-resistant isolate from beef, which was resistant to 8 antimicrobial drugs, the remaining 30 isolates were susceptible to the 14 antimicrobials tested. In conclusion, the finding of genetically similar isolates in cattle, beef, and humans may indicate a potential transmission of E. coli O157 from cattle to humans through beef. However, more robust studies are required to confirm this epidemiological link.

Contagious caprine pleuropneumonia (CCPP): A systematic review and meta-analysis of the prevalence in sheep and goats

Contagious caprine pleuropneumonia (CCPP) is a highly contagious respiratory disease of small ruminants that is caused by the bacterium Mycoplasma capricolum subsp. capripneumoniae. Sheep and goats are two of the species of small ruminants most at risk of CCPP. Outbreaks of CCPP cause significant economic and trade disturbances in several parts of the world. However, the extent and magnitude of CCPP in a particular geographical region is still not well known due to lack of comprehensive data on its occurrence. The present study aimed to investigate the prevalence of CCPP in sheep and goats raised in different geographical regions as well as the factors contributing to the spread of the disease. Searches were done in five online repositories: PubMed, Web of Science, Scopus, CAB Direct and Google Scholar using pre-selected key terms. Data were retrieved from the 41 articles that met the study's inclusion criteria. The pooled prevalences were determined using a random effect meta-analysis model. Prevalence of CCPP was 23.19% (95% CI: 11.90-34.47%) in sheep and 24.91% (95% CI: 20.99-28.84%) in goats. Overall, the regional level pooled prevalence estimates ranged from 8.0% (95% CI: 6.91-9.09%) to 28.70% (22.02-35.38%), depending on species and world region. Substantial heterogeneity (I²  > 75%) was observed in most pooled prevalence estimates. The results indicate high prevalences of CCPP in sheep and goats across the regions, particularly in Africa and Asia, and highlights the need to institute appropriate control measures. Active surveillance and research on risk factors are recommended.

Determination of the Microbial and Chemical Loads in Rivers from the Quito Capital Province of Ecuador (Pichincha)-A Preliminary Analysis of Microbial and Chemical Quality of the Main Rivers

Contamination of natural water sources is one of the main health problems worldwide, which could be caused by chemicals, metals, or microbial agents. This study aimed to analyze the quality of 18 rivers located in Quito, the capital province of Pichincha, Ecuador, through physico-chemical and microbial parameters. The E. coli and total coliforms assessments were performed by a counting procedure in growth media. Polymerase chain reaction (PCR) was realized to detect several microbial genera, as well as Candida albicans, two parasites (Cryptosporidium and Giardia spp.) and E. coli pathotypes: enterohemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC) and enteropathogenic E. coli (EPEC). Additionally, physico-chemical parameters and major and trace metals were analyzed in each surface water sample. Our results demonstrated that most of the rivers analyzed do not comply with the microbial, physico-chemical, and metal requirements established by the Ecuadorian legislation. In terms of microbial pollution, the most polluted rivers were Monjas, Machángara, Pisque, and Pita Rivers. Furthermore, three out of four analyzed E. coli pathotypes (EIEC, EHEC, and EAEC) were detected in certain rivers, specifically: Monjas River showed the presence of EIEC and EHEC; in the Machángara River, EAEC and EIEC were detected; and finally, EIEC was present in the Guayllabamba River. Several physico-chemical parameters, such as pH, COD_total, and TSS values, were higher than the Ecuadorian guidelines in 11, 28, and 28% of the rivers, respectively. Regarding heavy metals, Zn, Cu, Ni, Pb, Cd, and Mn surpassed the established values in 94, 89, 61, 22, 22, and 17% of the rivers, respectively. Machangara River was the only one that registered higher Cr concentrations than the national guidelines. The values of Al and Fe were above the recommended values in 83 and 72% of the rivers. Overall, based on the physical-chemical and microbiological parameters the most contaminated rivers were Machángara and Monjas. This study revealed severe contaminations in Ecuadorean Rivers; further studies should evaluate the sources of contamination and their impact on public health.

An Overview of the Elusive Passenger in the Gastrointestinal Tract of Cattle: The Shiga Toxin Producing Escherichia coli

For approximately 10,000 years, cattle have been our major source of meat and dairy. However, cattle are also a major reservoir for dangerous foodborne pathogens that belong to the Shiga toxin-producing Escherichia coli (STEC) group. Even though STEC infections in humans are rare, they are often lethal, as treatment options are limited. In cattle, STEC infections are typically asymptomatic and STEC is able to survive and persist in the cattle GIT by escaping the immune defenses of the host. Interactions with members of the native gut microbiota can favor or inhibit its persistence in cattle, but research in this direction is still in its infancy. Diet, temperature and season but also industrialized animal husbandry practices have a profound effect on STEC prevalence and the native gut microbiota composition. Thus, exploring the native cattle gut microbiota in depth, its interactions with STEC and the factors that affect them could offer viable solutions against STEC carriage in cattle.

Meta-Analysis and Meta-Regression Indicate Dynamic Prevalence and Moderators of Foodborne Pathogens in African Indigenous Fermented Milk

As more microbiological data for indigenous fermented milk (IFM) becomes available, concern about their microbial safety becomes eminent. Nonetheless, these data are highly fragmented, and a tool is required to integrate existing data and to provide a basis for data-driven decision making for IFM’s safety. Therefore, meta-analysis and meta-regression were conducted to estimate the prevalence of foodborne pathogens in IFM and to determine factors influencing the estimated values. Using Africa as a case, searches were systematically made for published data and relevant grey literature. Data from 18 studies in 15 countries were analyzed. Staphylococcus aureus (37%), pathogenic Escherichia coli (16%), Listeria monocytogenes (6%), and Salmonella spp. (3%) were the most prevalent pathogens with a pooled prevalence estimate of 12%. Heterogeneity among prevalence estimates was attributed to sampling point and microbial group but could be moderated by publication year, country cluster, and methods for microbial confirmation. The pooled prevalence estimates increased over time as more studies became available, whereby the odds were higher in studies from 2010 onwards than studies before 2010. From the analyses, S. aureus presented the greatest safety concern in African IFM. Future microbiological studies should take into consideration different IFM sampling points and advanced analytical methods to identify pathogens.

Escherichia coli O157:H7: distribution, molecular characterization, antimicrobial resistance patterns and source of contamination of sheep and goat carcasses at an export abattoir, Mojdo, Ethiopia

BACKGROUND

Cattle have been identified as a major reservoir of E. coli O157:H7 for human infection; the ecology of the organism in sheep and goats is less understood. This study was carried out to determine prevalence, source of infection, antibiotic resistance and molecular characterization of Escherichia coli O157: H7 isolated from sheep and goat.

METHODS

Systematic random sampling was carried out at Modjo export abattoir, Ethiopia, from November 2012 to April 2013 to collect 408 samples from 72 sheep and 32 goats. Samples collected were skin swabs, fecal samples, intestinal mucosal swabs and the inside and outside part of carcasses as well as carcass in contacts such as workers hands, knife, hook and carcass washing water. Then, samples were processed following standard bacteriological procedures. Non-Sorbitol fermenting colonies were tested on latex agglutination test and the positives are subjected to PCR for detection of attaching and effacing genes (eaeA) and shiga toxin producing genes (stx1 and stx2). All E. coli O157:H7 isolates were checked for their susceptibility pattern towards 15 selected antibiotics.

RESULTS

E. coli O157:H7 were detected in only 20/408 samples (4.9%). Among these 20 positive samples, 70% (14/20), 25% (5/20) and 5% (1/20) were from sheep, goats and knife samples, respectively. No significant associations were found between carcasses and the assumed sources of contaminations. Of all the 20 isolates virulence genes were found in 10 (50%) of them; 3 (15%) with only the eaeA gene and 7(35%) expressing eaeA and stx2 genes. All the isolates were susceptible to Norfloxacin (NOR) (100%).

CONCLUSIONS

The presence of virulence genes shows E. coli O157:H7 is a potential source of human infection in Ethiopia.

The global and regional prevalence of oestrosis in sheep and goats: a systematic review of articles and meta-analysis

Background

Oestrosis, caused by the larvae of Oestrus ovis, commonly known as sheep nose bot, is an obligatory cavitary myiasis of sheep and goats. Oestrus ovis is a widespread parasite, but little is known about the prevalence of oestrosis at the global and broad geographical levels. The present study aimed to explore the epidemiology of oestrosis at the global and regional level to estimate prevalences and their associated factors using a systematic approach. This is, to the author’s knowledge, the first meta-analysis of oestrosis in sheep and goats.

Methods

Published articles were obtained from nine electronic databases (PubMed, CAB Abstracts, Web of Science, Scopus, UCB library, Medline, Biosis Citation Index, Indian journals and Google Scholar) reporting the prevalence of O. ovis in sheep and goats from 1970 to 2018. Pooled prevalences were estimated using a random effect meta-analysis model.

Results

Sixty-six studies were eligible, and data from 40,870 sheep and 18,216 goats were used for quantitative analysis. The random effect estimated prevalence of oestrosis at the global level in sheep was 51.15% (95% CI: 42.80–59.51%) and in goats was 42.19% (95% CI: 33.43–50.95%). The pooled prevalence estimates for Africa, Asia, Europe and the Americas were 47.85% (95% CI: 36.04–59.66%), 44.48% (95% CI: 33.09–55.87%), 56.83% (95% CI: 48.92–64.74%) and 34.46% (95% CI: 19.90–49.01%), respectively. Heterogeneity (I² > 80%) was detected in most pooled estimates.

Conclusions

Oestrosis is highly prevalent in many geographical regions of the world, especially in Europe and Africa. Factors that contribute to the pooled prevalence estimate of oestrosis need to be emphasised in any survey to estimate the true prevalence of oestrosis. Furthermore, there is a need for immunisation or implementation of other preventive measures to reduce the burden of oestrosis in sheep and goats and to improve the health and welfare status.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3597-2) contains supplementary material, which is available to authorized users.

Prevalence and Serotype Diversity of Salmonella in Apparently Healthy Cattle: Systematic Review and Meta-Analysis of Published Studies, 2000-2017

Salmonellosis is a leading cause of foodborne illnesses in humans with cattle being one of the reservoirs for Salmonella. We estimated a pooled prevalence of Salmonella in apparently healthy cattle and examined serotype diversity through systematic review and meta-analysis of studies published between 2000 and 2017. Peer reviewed publications reporting the prevalence of Salmonella in cattle were searched through five electronic databases (PubMed, Google scholar, Agricola, Scopus, CAB direct) and through manual search. We obtained 71 publications with 75 datasets consisting a total of 52,766 animals examined and 5,010 Salmonella positive cattle from 29 countries in six continents (except from Antarctica). Pooled prevalence of Salmonella in cattle was 9% (95% confidence interval: 7-11%). Significantly high heterogeneity (I 2 = 98.7%, P < 0.01) was observed among all studies as well as within continents. Prevalence varied from 2% (Europe) to 16% (North America). Overall, 143 different serotypes were reported with the most diverse serotypes being reported from Africa (76 different serotypes) followed by North America (49 serotypes). The 10 most frequently reported serotypes (Montevideo, Typhimurium, Kentucky, Meleagridis, Anatum, Cerro, Mbandaka, Muenster, Newport, and Senftenberg) accounted for 65% of the isolates for which specific serotype information was reported. Salmonella Montevideo and S. Dublin are the most frequently reported serotypes in North America and Europe, respectively, while S. Typhimurium was the most frequent in Africa, Asia and Australasia. Our results indicated variability both in the prevalence and serotype diversity of Salmonella in cattle across continents. Although all Salmonella serotypes are potentially pathogenic to humans, five (Montevideo, Typhimurium, Anatum, Mbandaka, and Newport) of the top 10 serotypes identified in this study are among the serotypes most commonly associated with clinical illnesses in humans.

Recent Advances in Shiga Toxin-Producing Escherichia coli Research in Latin America

Pathogenic Escherichia coli are known to be a common cause of diarrheal disease and a frequently occurring bacterial infection in children and adults in Latin America. Despite the effort to combat diarrheal infections, the south of the American continent remains a hot spot for infections and sequelae associated with the acquisition of one category of pathogenic E. coli, the Shiga toxin-producing E. coli (STEC). This review will focus on an overview of the prevalence of different STEC serotypes in human, animals and food products, focusing on recent reports from Latin America outlining the recent research progress achieved in this region to combat disease and endemicity in affected countries and to improve understanding on emerging serotypes and their virulence factors. Furthermore, this review will highlight the progress done in vaccine development and treatment and will also discuss the effort of the Latin American investigators to respond to the thread of STEC infections by establishing a multidisciplinary network of experts that are addressing STEC-associated animal, human and environmental health issues, while trying to reduce human disease. Regardless of the significant scientific contributions to understand and combat STEC infections worldwide, many significant challenges still exist and this review has focus in the Latin American efforts as an example of what can be accomplished when multiple groups have a common goal.

Genotypic Features of Clinical and Bovine Escherichia coli O157 Strains Isolated in Countries with Different Associated-Disease Incidences

There is great geographical variation in the frequency of Escherichia coli O157 infections that correlates with important differences in the bovine reservoir of each country. Our group carried out a broad molecular characterization of human and bovine E. coli O157 strains circulating in Argentina using different methodologies. Our data allows us to conclude that in Argentina, a high homogeneity is observed in both cattle and human strains, with almost exclusive circulation of strains belonging to the hypervirulent clade 8 described by Manning. The aim of this review was to compare the genetic background of E. coli O157 strains isolated in countries that have conducted similar studies, to try to correlate specific O157 genotypes with the incidence and severity of E. coli O157 associated diseases. The characteristics of the strains that cause disease in humans reflect the predominant genotypes in cattle in each of the countries analyzed. The main features clearly linked to high incidence or severity of E. coli O157 infections are lineage-specific polymorphism assay-6 lineage I/II, clade 8 strains and probably, clade 6 strains, the stx_2a/stx_2c genotype, the presence of q933 and q21 simultaneously, and putative virulence factor EC_3286. In countries with an absence of these features in O157 strains, the overall incidence of O157 disease is low. Argentina, where these characteristics are detected in most strains, shows the highest incidence of hemolytic uremic syndrome (HUS) worldwide.

A four-season longitudinal study of enterohaemorrhagic Escherichia coli in beef cow-calf herds in Mississippi and Nebraska

Our objective was to describe the probability of detecting seven serogroups of enterohaemorrhagic Escherichia coli (EHEC-7) of public health importance in faecal samples from beef cow-calf herds and to test for factors associated with their detection. Fresh faecal samples (n = 85) from two Mississippi and two Nebraska herds were collected in each of four seasons. Samples were tested for each EHEC-7 serogroup by a molecular screening assay. Separate management groups within herds were sampled, and group-level factors were recorded. To measure the effects of factors on faecal shedding of EHEC-7, separate multivariable logistic regression models were used, accounting for the random effect of clustering by group within farm. Statistical significance was set α = 0.05. Fifty-nine samples (4.3%) were positive for EHEC O26, and Nebraska samples were more likely to be positive than Mississippi samples (OR = 12.4, 95% CI: 1.1, 139.2). Forty-four samples (3.2%) were positive for EHEC O45. Odds for detection were greater in the summer than all other seasons combined (OR = 4.2, 95% CI: 1.3, 14.0), and odds decreased if a precipitation event occurred (OR = 0.07, 95% CI: 0.006, 0.8). EHEC O103 was detected in 66 samples (4.9%) with increased probability to be detected at increased temperature. EHEC O111 was detected in 71 samples (5.2%), and 43 samples (3.2%) were positive for EHEC O145. Both EHEC O111 and O145 were associated separately with season, with greater probability for detection in the summer. Eighteen (1.3%) and 68 (5.0%) samples were positive for EHEC O121 and EHEC O157, respectively. We failed to detect significant explanatory factors associated with probability to detect EHEC O121 or O157. Factors that vary by time and place, such as precipitation, ambient temperature, region and season, are uniquely associated with the probability to detect EHEC-7 in fresh faeces collected from cow-calf herds.

Shiga Toxin-Producing Escherichia coli O157 Shedding Dynamics in an Australian Beef Herd

Shiga toxin-producing Escherichia coli (STEC) O157 is an important foodborne pathogen that can be transmitted to humans both directly and indirectly from the feces of beef cattle, its primary reservoir. Numerous studies have investigated the shedding dynamics of E. coli O157 by beef cattle; however, the spatiotemporal trends of shedding are still not well understood. Molecular tools can increase the resolution through the use of strain typing to explore transmission dynamics within and between herds and identify strain-specific characteristics that may influence pathogenicity and spread. Previously, the shedding dynamics and molecular diversity, through the use of multilocus variable number of tandem repeat analysis (MLVA) of STEC O157, were separately investigated in an Australian beef herd over a 9-month study period. Variation in shedding was observed over time, and 33 MLVA types were identified. The study presented here combines the two datasets previously published with an aim to clarify the relationship between epidemiological variables and strain types. Three major genetic clusters (GCs) were identified that were significantly associated with the location of the cattle in different paddocks. No significant association between GCs and individual cow was observed. Results from this molecular epidemiological study provide evidence for herd-level clonal replacement over time that may have been triggered by movement to a new paddock. In conclusion, this study has provided further insight into STEC O157 shedding dynamics and pathogen transmission. Knowledge gaps remain regarding the relationship of strain types and the shedding dynamics of STEC O157 by beef cattle that could be further clarified through the use of whole-genome sequencing.

Frequency and risk-factors analysis of Escherichia coli O157:H7 in Bali-cattle

Cattle are known as the main reservoir of zoonotic agents verocytotoxin-producing Escherichia coli. These bacteria are usually isolated from calves with diarrhea and/or mucus and blood. Tolerance of these agents to the environmental conditions will strengthen of their transmission among livestock. A total of 238 cattle fecal samples from four sub-districts in Badung, Bali were used in this study. Epidemiological data observed include cattle age, sex, cattle rearing system, the source of drinking water, weather, altitude, and type of cage floor, the cleanliness of cage floor, the slope of cage floor, and the level of cattle cleanliness. The study was initiated by culturing of samples onto eosin methylene blue agar, then Gram stained, and tested for indole, methyl-red, voges proskauer, and citrate, Potential E.coli isolates were then cultured onto sorbitol MacConkey agar, and further tested using O157 latex agglutination test and H7 antisera. Molecular identification was performed by analysis of the 16S rRNA gene, and epidemiological data was analyzed using STATA 12.0 software. The results showed, the prevalence of E. coli O157:H7 in cattle at Badung regency was 6.30% (15/238) covering four sub districts i.e. Petang, Abiansemal, Mengwi, and Kuta which their prevalence was 8.62%(5/58), 10%(6/60), 3.33%(2/60), and 3.33(2/60)%, respectively. The analysis of 16S rRNA gene confirmed of isolates as an E. coli O157:H7 strain with 99% similarities. Furthermore, the risk factors analysis showed that the slope of the cage floor has a highly significant effect (P<0.05) to the distribution of infection. Consequently, implementing this factor must be concerned in order to decrease of infection.

Potential for Meta-Analysis in the Realm of Preharvest Food Safety

Meta-analysis, the statistical combination of results from multiple studies, can be used to summarize all of the available research on an intervention, etiology, descriptive, or diagnostic test accuracy question. Meta-analysis should be conducted as a component of a systematic review, to increase transparency in the selection of studies and to incorporate an evaluation of the risk of bias in the individual studies included in the meta-analysis. The process of meta-analysis may include a forest plot to graphically display the study results and the calculation of a weighted average summary effect size. Heterogeneity (differences in the effect size between studies) can be evaluated using formal statistics and the reasons for heterogeneity can be explored using sub-group analysis or meta-regression. Thus, meta-analysis may be a useful methodology for preharvest food safety research to aid in policy or clinical decision-making or to provide input to quantitative risk assessment or other models.

A study on association of virulence determinants of verotoxic Escherichia coli isolated from cattle calves

AIM

The present study was conducted to find the association among virulence determinants of verotoxic Escherichia coli (VTEC) isolated from cattle calf feces.

MATERIALS AND METHODS

A total of 216 cattle calf fecal samples were collected aseptically and processed under required conditions for the isolation of E. coli. The isolates were further subjected to multiplex polymerase chain reaction (mPCR) for the detection of virulent genes. All the VTEC isolates were serotyped at the Central Research Institute, Kasauli, Himachal Pradesh. The VTEC isolates were observed for the enterohemolysin production on washed sheep blood agar (wSBA).

RESULTS

A total of 177 presumptive E. coli were isolated from 216 calf fecal samples revealing an overall prevalence of E. coli to be 81.94%. A total of 32 (14.81%) isolates were detected as VTEC through mPCR. The prevalence of verotoxin genes vt1, vt2, and combination of vt1+vt2 in the VTEC isolates was found to be 12 (37.5%), 14 (43.75%), and 6 (18.75%), respectively. Other virulent genes eaeA and hlyA were found in 6 and 11 VTEC strains with prevalence values of 18.75% and 34.37%, respectively. A total of 13 different O serogroups were revealed in serotyping of 32 VTEC isolates. Out of 32 VTEC strains, only 26 (81.25%) were enterohemolytic on wSBA as they produced the characteristic small, turbid zone of hemolysis around the streaking line. Although enterohemolysin production has been attributed to the presence of hlyA gene, only 11 of 26 enterohemolysin producing VTEC were found to be harboring the hlyA gene (11/26) 42.03%.

CONCLUSION

The present study concludes that there might be an association between the presence of verotoxin genes and enterohemolysin production in VTEC group of E. coli.

Phylogenomic approaches to determine the zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) isolated from Zambian dairy cattle

This study assessed the prevalence and zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) sampled from 104 dairy units in the central region of Zambia and compared these with isolates from patients presenting with diarrhoea in the same region. A subset of 297 E. coli strains were sequenced allowing in silico analyses of phylo- and sero-groups. The majority of the bovine strains clustered in the B1 ‘commensal’ phylogroup (67%) and included a diverse array of serogroups. 11% (41/371) of the isolates from Zambian dairy cattle contained Shiga toxin genes (stx) while none (0/73) of the human isolates were positive. While the toxicity of a subset of these isolates was demonstrated, none of the randomly selected STEC belonged to key serogroups associated with human disease and none encoded a type 3 secretion system synonymous with typical enterohaemorrhagic strains. Positive selection for E. coli O157:H7 across the farms identified only one positive isolate again indicating this serotype is rare in these animals. In summary, while Stx-encoding E. coli strains are common in this dairy population, the majority of these strains are unlikely to cause disease in humans. However, the threat remains of the emergence of strains virulent to humans from this reservoir.

Prevalence and concentration of Escherichia coli O157 in different seasons and cattle types processed in North America: A systematic review and meta-analysis of published research

Systematic review (SR) and meta-analyses (MA) methodologies were used to identify, critically evaluate and synthesize prevalence and concentration estimates for Escherichia coli O157 contamination along the beef production chain, and to illustrate differences based on cattle types and seasonality in North America from the scientific peer-reviewed literature. Four electronic databases were searched to identify relevant articles. Two independent reviewers performed all SR steps. Random effects MA models were used to estimate the pooled prevalence and concentration of E. coli O157 in feces, hides and carcasses of cattle processed in North America, including their seasonal estimates. The potential sources of between studies heterogeneity were identified using meta-regression and sub-group analysis. Results indicated differences in the fecal prevalence of E. coli O157 among cattle types: 10.68% (95% CI: 9.17-12.28%) in fed beef, 4.65% (95% CI: 3.37-6.10%) in adult beef, and 1.79% (95% CI: 1.20-2.48%) in adult dairy. Fed beef fecal prevalence was 10.65% (95% CI: 8.93-12.49%) during summer and 9.17% (95% CI: 5.24-13.98%) during the winter months. For adult beef, the fecal prevalence was 7.86% (95% CI: 5.43-10.66%) during summer, and 4.21% (95% CI: 1.95-7.13%) during winter. Among adult dairy, the fecal prevalence was 2.27% (95% CI: 1.5-3.18%) during summer, and 0.36% (95% CI: 0.09-0.74%) during winter. There was a significantly higher percentage of hides with E. coli O157 concentration ≥ 40 CFU/100 cm(2) on hides of fed beef sampled at the processing plant (23.81%; 95% CI: 14.79-34.15%) compared to those sampled at the feedlot (1.74%; 95% CI: 0.53-3.44%). Prevalence of E. coli O157 on carcass surfaces differed by season only at the post-evisceration stage, but decreased considerably through the subsequent processing stages. Country, study setting, detection method, hide swab area, and study design were identified as significant sources of heterogeneity among studies reporting prevalence of E. coli O157 along the beef production chain. The pooled prevalence and concentration estimates from this study provide a sound and reliable microbiological basis for risk assessment modeling of E. coli O157 and other pathogens in the food chain.

Multilocus genotypic characterization of Escherichia coli O157:H7 recovered from food sources

Escherichia coli O157:H7 strains (n = 33) recovered from different food sources in Egypt were characterized using molecular assays to identify strain genotypes associated with various levels of pathogenic potential. Genotypic characterization included: lineage-specific polymorphism assay (LSPA-6), Shiga-toxin-encoding bacteriophage insertion site assay (SBI), clade 8 typing, Tir (A255 T) polymorphism, and variant analysis of Shiga toxin 2 gene (Stx 2a and Stx 2c), and anti-terminator Q genes (Q 933 and Q 21). Genotypes LI/II (76%), SBI 1 (60·6%), clade 8 (69·7%), Tir (255 T) (72·7%) and Stx 2c (45·5%) were found to be significantly more frequent compared to other genetic markers in the strains analysed. Multivariable analysis revealed a significant association between LPSA-6 and clade types as well as Tir (A255 T). To the best of our knowledge, this is the first study to report the characterization of these genetic markers in E. coli O157:H7 strains in the Middle East and Africa.