Multiclonal human origin and global expansion of an endemic bacterial pathogen of livestock.

Most new pathogens of humans and animals arise via switching events from distinct host species. However, our understanding of the evolutionary and ecological drivers of successful host adaptation, expansion, and dissemination are limited. Staphylococcus aureus is a major bacterial pathogen of humans and a leading cause of mastitis in dairy cows worldwide. Here we trace the evolutionary history of bovine S. aureus using a global dataset of 10,254 S. aureus genomes including 1,896 bovine isolates from 32 countries in 6 continents. We identified 7 major contemporary endemic clones of S. aureus causing bovine mastitis around the world and traced them back to 4 independent host-jump events from humans that occurred up to 2,500 y ago. Individual clones emerged and underwent clonal expansion from the mid-19th to late 20th century coinciding with the commercialization and industrialization of dairy farming, and older lineages have become globally distributed via established cattle trade links. Importantly, we identified lineage-dependent differences in the frequency of host transmission events between humans and cows in both directions revealing high risk clones threatening veterinary and human health. Finally, pangenome network analysis revealed that some bovine S. aureus lineages contained distinct sets of bovine-associated genes, consistent with multiple trajectories to host adaptation via gene acquisition. Taken together, we have dissected the evolutionary history of a major endemic pathogen of livestock providing a comprehensive temporal, geographic, and gene-level perspective of its remarkable success.

Clonal diversity of Staphylococcus aureus isolates in clinical specimens from selected health facilities in Ethiopia.

Staphylococcus aureus is among the top three causative agents of nosocomial infection in Ethiopia. The majority of studies in Ethiopia have focused on the epidemiology of S. aureus in hospital settings, with limited molecular genotyping results. Molecular characterization of S. aureus is essential for identification of strains, and contributes to the control and prevention of S. aureus infection. The aim of the current study was to determine the molecular epidemiology of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates recovered from clinical specimens in Ethiopia. A total of 161 MSSA and 9 MRSA isolates were characterized using pulsed-field gel electrophoresis (PFGE) and staphylococcal protein A (spa) typing. Based on the PFGE analysis, MSSA isolates were grouped into eight pulso-types groups (from A to I), while MRSA isolates clustered into three (A, B and C) pulso-types with more than 80% similarity. The spa typing analysis showed diversity of S. aureus with 56 distinct spa types. Spa type t355 was most prevalent (56/170, 32.9%), while eleven new spa types were detected including t20038, t20039, and t20042. The identified spa types were clustered into 15 spa-clonal complexes (spa-CCs) using BURP analysis; novel/unknown spa types were further subjected to MLST analysis. The majority of isolates belonged to spa-CC 152 (62/170, 36.4%), followed by spa-CC 121 (19/170, 11.2%), and spa-CC 005 (18 /170, 10.6%). Of the nine MRSA isolates, 2 (22.2%) were spa-CC 239 with staphylococcal cassette chromosome (SCC)mec III. These findings highlight the diversity of S. aureus strains in Ethiopia, as well as the presence of potentially epidemic strains circulating in the country necessitating further characterization of S. aureus for antimicrobial resistance detection and infection prevention purposes.

Burden and antimicrobial resistance of S. aureus in dairy farms in Mekelle, Northern Ethiopia.

BACKGROUND: Staphylococcus aureus is a frequent colonizer of human and several animal species, including dairy cows. It is the most common cause of intramammary infections in dairy cows. Its public health importance increases inline to the continuous emergence of drug-resistant strains; such as Methicillin-resistant S. aureus (MRSA). Indeed, the recent emergence of human and veterinary adapted MRSA demands serious attention. The aim of this study was to determine the burden and drug resistance pattern of S. aureus in dairy farms in Mekelle and determine the molecular characteristics of MRSA. RESULTS: This study was done on 385 lactating dairy cows and 71 dairy farmers. The ages of the cows and farmworkers were between 3 and 14 and 17-63 years respectively. S. aureus was isolated from 12.5% of cows and 31% of farmworkers. Highest resistance was observed for penicillin (> 90%) followed by tetracycline (32-35%) and trimethoprim-sulphamethoxazole (10-27%). But no resistance was observed for vancomycin, daptomycin, and rifampin. Only one isolate was MRSA both phenotypically and harboring mecA. This isolate was from nasal of a farmworker and was MRSA SCCmec Iva, spa type t064 of CC8. Multi-drug resistance was observed in 6.2% of cow isolates and 13.6% of nasal isolates. CONCLUSIONS: In this study, S. aureus infected 12.5% of dairy cows and colonized 31% of farmworkers. Except for penicillin, resistance to other drugs was rare. Although no MRSA was found from dairy cows the existence of the human and animal adapted and globally spread strain, MRSA SCCmec IVa spa t064, warrants for a coordinated action to tackle AMR in both human and veterinary in the country.

Fecal prevalence, serotype distribution and antimicrobial resistance of Salmonellae in dairy cattle in central Ethiopia.

BACKGROUND: Salmonellae are major worldwide zoonotic pathogens infecting a wide range of vertebrate species including humans. Consumption of contaminated dairy products and contact with dairy cattle represent a common source of non-typhoidal Salmonella infection in humans. Despite a large number of small-scale dairy farms in Addis Ababa and its surrounding districts, little is known about the status of Salmonella in these farms. RESULTS: Salmonella was recovered from the feces of at least one animal in 7.6% (10/132) of the dairy farms. Out of 1203 fecal samples examined, 30 were positive for Salmonella resulting in a weighted animal level prevalence of 2.3%. Detection of diarrhea in an animal and in a farm was significantly associated with animal level (p = 0.012) and herd level (p < 0.001) prevalence of Salmonella. Animal level prevalence of Salmonella was significantly associated with age (p = 0.023) and study location; it was highest among those under 6 months of age and in farms from Adaa district and Addis Ababa (p < 0.001). Nine different serotypes were identified using standard serological agglutination tests. The most frequently recovered serotypes were Salmonella Typhimurium (23.3%), S. Saintpaul (20%), S. Kentucky (16.7%) and S. Virchow (16.7%). All isolates were resistant or intermediately resistant to at least one of the 18 drugs tested. Twenty-six (86.7%), 19 (63.3 %), 18 (60%), 16 (53.3%) of the isolates were resistant to streptomycin, nitrofurantoin, sulfisoxazole and tetracycline , respectively. Resistance to 2 drugs was detected in 27 (90%) of the isolates. Resistance to 3 or more drugs was detected in 21 (70%) of the isolates, while resistance to 7 or more drugs was detected in 11 (36.7%) of the isolates. The rate of occurrence of multi-drug resistance (MDR) in Salmonella strains isolated from dairy farms in Addis Ababa was significantly higher than those isolated from farms outside of Addis Ababa (p = 0.009). MDR was more common in S. Kentucky, S. Virchow and S. Saintpaul. CONCLUSION: Isolation of Salmonella serotypes commonly known for causing human salmonellosis that are associated with an MDR phenotype in dairy farms in close proximity with human population is a major public health concern. These findings imply the need for a strict pathogen reduction strategy.

Non-typhoidal Salmonella serotypes, antimicrobial resistance and co-infection with parasites among patients with diarrhea and other gastrointestinal complaints in Addis Ababa, Ethiopia.

BACKGROUND: Non-typhoidal Salmonella (NTS) is an important public health problem worldwide. Consumption of animal-derived food products and direct and/or indirect contact with animals are the major routes of acquiring infection with NTS. Published information, particularly on the serotype distribution of NTS among human patients with gastroenteritis and associated risk factors, is scarce in Ethiopia. This study investigated the prevalence, risk factors, serotype distribution and antimicrobial susceptibility of Salmonella species among diarrheic out-patients attending health centers in Addis Ababa and patients with various gastrointestinal complaints at Tikur Anbessa Specialized Hospital (TASH). METHODS: Stool samples were cultured for Salmonella species according to the WHO Global Foodborne Infections Network laboratory protocol. Salmonella serotyping was conducted using slide agglutination and microplate agglutination techniques. Antibiotic susceptibility testing was performed using the disk diffusion method according to Clinical and Laboratory Standards Institute guidelines. RESULTS: A total of 59 (6.2 %) stool samples, out of 957 were culture positive for Salmonella species. Fifty-five (7.2 %) of 765 diarrheic patients from health centers and 4 (2.1 %) of 192 patients from TASH were culture positive for Salmonella species. Multivariable logistic regression analysis after adjusting for all other variables revealed statistically significant association of Salmonella infection with consumption of raw vegetables (OR = 1.91, 95 % CI = 1.29-2.83, χ(2) = 4.74, p = 0.025) and symptom of watery diarrhea (OR = 3.3, 95 % CI = 1.23-8.88, χ(2) = 10.54, p = 0.005). Eleven serotypes were detected, and the most prominent were S. Typhimurium (37.3 %), S. Virchow (34 %), and S. Kottbus (10.2 %). Other serotypes were S. Miami, S. Kentucky, S. Newport, S. Enteritidis, S. Braenderup, S. Saintpaul, S. Concord and S. V:ROUGH-O. Resistance to three or more antimicrobials was detected in 27 (40.3 %) of the isolates. Resistance to five or more antimicrobials was detected in 17 (25.4 %). Resistance to individual antimicrobials was found at varying proportions: streptomycin (50; 74.6 %), nitrofurantoin (27; 40.3 %), sulfisoxazole (26; 38.8 %), kanamycin (23; 34.3 %), cephalothin (12; 17.9 %), and ampicillin (11; 16.4 %) respectively. Two S. Kentucky, one S. Typhimurium and one S. Concord isolates were multi-drug resistant to more than 10 antimicrobials. CONCLUSIONS: The study demonstrated significant association of Salmonella infection with consumption of raw vegetables. There was no significant association of Salmonella infection with co-occurring parasites. The study also showed the dominance of S. Typhimurium and S. Virchow in primary health care units. Overall, prevalence of MDR was low compared to previous studies. Although their proportion was low, S. Kentucky and S. Concord demonstrated wider spectrum of MDR. Continuous monitoring of circulating serotypes, antimicrobial resistance profile and characterization on molecular resistance determinants is essential for proper treatment of patients and for identifying potential environmental origins of antimicrobial resistance.

Supplementation with Quaternary Benzo(c)phenanthridine Alkaloids Decreased Salivary Cortisol and Salmonella Shedding in Pigs After Transportation to the Slaughterhouse.

The present study was aimed at evaluating the effect of herbal extracts supplementation, particularly quaternary-benzo(c)phenanthridine alkaloids (QBA), which have been previously demonstrated to have anti-inflammatory, antimicrobial, and immune-modulator effects. We investigated the role of QBA on stress response and Salmonella shedding in finishing pigs transported to the slaughterhouse. A total of 82 pigs were orally challenged with a Salmonella cocktail (day 0) containing Salmonella Meleagridis, Hartford, Bovismorbificans and Newport serovars and randomly assigned to three treatment groups after 2 wks (day [D] 14): T1, in-feed QBA; T2, in-feed and water-soluble QBA; CON, nonsupplemented). Pigs were transported to the slaughterhouse 2 weeks after intervention (D 28) and slaughtered after nearly 19 h (D 29). Saliva, fecal samples, and carcass swabs were collected from all pigs. Salivary cortisol, Salmonella shedding, and carcass contamination were measured. A high positive correlation (Spearman rank correlation coefficient range 0.82-0.93) between salivary cortisol and Salmonella shedding was found after transportation in all groups (p < 0.05). Only the CON group showed an increase in salivary cortisol after transportation (5.48 ng/mL; p < 0.0001) to concentrations that were higher than in T1 (2.73 ng/mL; p = 0.0002) and T2 (1.88 ng/mL; p < 0.0001). Salmonella prevalence and shedding decreased after transportation in pigs receiving the QBA intervention (p < 0.05), whereas the control group showed a significant increase in Salmonella shedding after transportation (p = 0.04). At D 28, pigs in T2 shed lower numbers of Salmonella as compared to T1 (1.3E + 02 CFU/mL versus 8E + 03 CFU/mL; p = 0.002). Additionally, carcass contamination by Salmonella was higher in the CON group than the treated groups (p = 0.01). The findings show QBA intervention was effective in reducing transportation stress of pigs, resulting in reduced Salmonella shedding and positively impacting animal welfare and pork safety.

In-feed use of heavy metal micronutrients in U.S. swine production systems and its role in persistence of multidrug-resistant salmonellae.

The study aimed to characterize the role of heavy metal micronutrients in swine feed in emergence of heavy-metal-tolerant and multidrug-resistant Salmonella organisms. We conducted a longitudinal study in 36 swine barns over a 2-year period. The feed and fecal levels of Cu(2+) and Zn(2+) were measured. Salmonella was isolated at early and late finishing. MICs of copper sulfate and zinc chloride were measured using agar dilution. Antimicrobial susceptibility was tested using the Kirby-Bauer method, and 283 isolates were serotyped. We amplified pcoA and czcD genes that encode Cu(2+) and Zn(2+) tolerance, respectively. Of the 283 isolates, 113 (48%) showed Cu(2+) tolerance at 24 mM and 164 (58%) showed Zn(2+) tolerance at 8 mM. In multivariate analysis, serotype and source of isolates were significantly associated with Cu(2+) tolerance (P < 0.001). Fecal isolates were more likely to be Cu(2+) tolerant than those of feed origin (odds ratio [OR], 27.0; 95% confidence interval [CI], 2.8 to 250; P = 0.0042) or environmental origin (OR, 5.8), implying the significance of gastrointestinal selective pressure. Salmonella enterica serotypes Typhimurium and Heidelberg, highly significant for public health, had higher odds of having >20 mM MICs of Cu(2+) than did "other" serotypes. More than 60% of Salmonella isolates with resistance type (R-type) AmStTeKm (32 of 53) carried pcoA; only 5% with R-type AmClStSuTe carried this gene. czcD gene carriage was significantly associated with a higher Zn(2+) MIC (P < 0.05). The odds of having a high Zn(2+) MIC (≥8 mM) were 14.66 times higher in isolates with R-type AmClStSuTe than in those with R-type AmStTeKm (P < 0.05). The findings demonstrate strong association between heavy metal tolerance and antimicrobial resistance, particularly among Salmonella serotypes important in public health.

Pre-parturition staphylococcal mastitis in primiparous replacement goats: persistence over lactation and sources of infection.

This investigation reported for the first time the occurrence of intramammary infections caused by Staphylococcus in primiparous replacement goats before parturition and the persistence of clinical Staphylococcus aureus infection during the lactation period. Subclinical infections, mainly caused by coagulase negative staphylococci (CoNS), did not persist during lactation. Genotyping analysis indicated that environment seems to play a moderate role as source of intramammary infections to goats before parturition, but causative agents of mastitis in lactating animals are not genotypically related to environmental staphylococci. The occurrence and persistence of intramammary infections in replacement goats demonstrate the need to consider those animals as potential sources of infections in dairy goat herds.

Association of multicellular behaviour and drug resistance in Salmonella enterica serovars isolated from animals and humans in Ethiopia.

AIMS: To determine the association between multicellular behaviour, integron status and antibiotic resistance among 87 Ethiopian Salmonella enterica isolates of animal and human origin. METHODS AND RESULTS: Isolates were characterized for their biofilm forming ability, antimicrobial susceptibility and the presence and characteristics of a class 1 integron and Salmonella genomic island 1 (SGI1). The majority of isolates grown at environmental temperatures (20°C) exhibited robust biofilm formation (72·4%) and displayed RDAR colony morphology on Congo red agar plates. The presence of a class 1 integron correlated with the extent of drug resistance and ability to exhibit multicellular behaviour. CONCLUSIONS: Although cellulose production and RDAR morphology correlated with increased multicellular behaviour, neither was required for biofilm formation. Contrary to previous reports, colony morphology was generally consistent within a serovar. No integrons were detected in isolates deficient for multicellular behaviour, indicating a potential role of bacterial community formation in transfer of genetic elements among environmental isolates. SIGNIFICANCE AND IMPACT OF STUDY: Infection by Salm. enterica is a major public health problem worldwide. The dominance of multidrug resistance and multicellular behaviour in Salmonella isolates of Ethiopian origin highlights a need for integrated surveillance and further detailed phenotypic and molecular studies of isolates from this region.

Comparative phenotypic and genotypic characterization of temporally related nontyphoidal Salmonella isolated from human clinical cases, pigs, and the environment in North Carolina.

Nontyphoidal Salmonella infections caused by antimicrobial-resistant (AMR) strains are of great public health concern. We compared the phenotypic and genotypic relationships among temporally and spatially related AMR Salmonella isolates (n=1058) representing several predominant serovars, including Salmonella Typhimurium, Salmonella Typhimurium var. 5-, Salmonella Derby, Salmonella Heidelberg, Salmonella Muenchen, Salmonella Schwarzengrund, and Salmonella Rissen of human clinical cases (n=572), pig (n=212), and farm environment (n=274) origin in North Carolina. Antimicrobial susceptibility testing was performed using the broth microdilution method, and genotypic resistance determinants, including class I and II integrons, were identified. Overall, Salmonella isolates exhibited the highest frequency of resistance to tetracycline (50%), followed by sulfisoxazole (36%) and streptomycin (27%). We identified 16 different antimicrobial resistance genes, including extended spectrum and AmpC ß-lactamases-producing genes (bla(TEM), bla(PSE), and bla(CMY-2)), in all the ß-lactam- and cephalosporin-resistant Salmonella isolates from humans, pigs, and the environment. Class I integrons of 1-kb and 1.2-kb size were identified from all the three sources (humans, 66%; pigs, 85%; environment, 58%), while Class II integrons of 2-kb size were identified only in pig (10%) and environmental (19%) isolates. We detected genotypic similarity between Salmonella Typhimurium isolated from humans, pigs, and the environment while serovars Derby, Heidelberg, and Muenchen exhibited genotypic diversity. Detection of AMR Salmonella isolates from humans, pigs, and the environment is a concern for clinicians and veterinarians to mitigate the dissemination of AMR Salmonella strains.

Escherichia coli isolates from vegetable farms in Addis Ababa, Ethiopia: Antimicrobial susceptibility profile and associated resistance genetic markers.

The use of animal manure to fertilize soil is an emerging concern contributing to the transfer of antimicrobial-resistant pathogens to vegetables. Hence, assessing antimicrobial susceptibility profile of Escherichia coli in vegetable farms is essential to design appropriate interventions against antimicrobial resistance (AMR) in the food chain. This study assessed antimicrobial resistance profile and associated genetic markers among E. coli isolated from vegetable farms fertilized with animal manure in Addis Ababa, Ethiopia. A total of 1044 samples were collected using convenience sampling: soil (n = 271), manure (n = 375), and vegetables (n = 398) from 81 vegetable farms in Addis Ababa, Ethiopia. Antimicrobial susceptibility test was conducted for 100 E. coli isolates and antimicrobial resistance genes (ARGs) were tested by polymerase chain reaction (PCR). Of the 1044 collected samples, 25.3% were positive for E. coli, with significantly higher prevalence in the manure sample and samples collected from Akaki Kality sub-city (p < .05). The highest resistance rate was recorded for tetracycline (72%), followed by streptomycin (63%), and sulfamethoxazole +trimethoprim (56%). Multidrug resistance was detected in 61% of the E. coli isolates. The aac(3)-IV (76.9%), bla TEM (65.4%), aadA (60.3%), tet(A) (58.3%), and sulI (51.7%) were the commonly detected resistance genes. The current study showed a high burden of antimicrobial resistance among E. coli isolated from manure-amended vegetable farms, with potential of playing a significant role in the dissemination of antimicrobial resistance in the food chain. Efforts should be made to reduce the burden of resistant organisms and ARGs through prudent use of antimicrobials in livestock and application of appropriate composting techniques before using manure as fertilizer.

Pre-Harvest Food Safety Challenges in Food-Animal Production in Low- and Middle-Income Countries.

Food safety remains a significant global public health concern, with the risk of unsafe food varying worldwide. The economies of several low- and middle-income countries (LMICs) heavily rely on livestock, posing a challenge to ensuring the production of safe food. This review discusses our understanding of pre-harvest critical issues related to food safety in LMICs, specifically focusing on animal-derived food. In LMICs, food safety regulations are weak and inadequately enforced, primarily concentrating on the formal market despite a substantial portion of the food sector being dominated by informal markets. Key critical issues at the farm level include animal health, a low level of good agriculture practices, and the misuse of antimicrobials. Effectively addressing foodborne diseases requires a comprehensive One Health framework. Unfortunately, the application of the One Health approach to tackle food safety issues is notably limited in LMICs. In conclusion, considering that most animal-source foods from LMICs are marketed through informal channels, food safety legislation and policies need to account for this context. Interventions aimed at reducing foodborne bacterial pathogens at the farm level should be scalable, and there should be strong advocacy for the proper implementation of pre-harvest interventions through a One Health approach.

Whole genome sequence datasets of Salmonella enterica serovar Saintpaul ST50 and serovar Worthington ST592 strains isolated from raw milk in Brazil.

Herein we report the draft genome sequences of Salmonella enterica subsp. enterica serovars Saintpaul ST50 and Worthington ST592 isolated from raw milk samples in Northeastern Brazil. The 4,696,281 bp S. Saintpaul ST50 genome contained 4,628 genes in 33 contigs, while S. Worthington ST592 genome was 4,890,415 bp in length, comprising 4,951 genes in 46 contigs. S. Worthington ST592 carried a conserved Col(pHAD28) plasmid which contains the antimicrobial resistance determinants tet(C), acc(6')-Iaa, and a nonsynonymous point mutation in ParC (p.T57S). The data could support further evolutionary and epidemiologic studies involving Salmonella organisms.

Prevalence of porcine noroviruses, molecular characterization of emerging porcine sapoviruses from finisher swine in the United States, and unified classification scheme for sapoviruses.

Noroviruses (NoVs) and sapoviruses (SaVs) are important human pathogens. Although the involvement of porcine NoVs in disease in pigs is unclear, they are genetically and antigenically closely related to human NoVs. Human NoV-like strains have been detected in pigs, raising public health concerns of potential interspecies transmission. Porcine SaVs are highly diverse and emerging in swine populations. Recently, at least three new genogroups of porcine SaVs have been proposed. In this study, we tested 413 pooled fecal samples collected from apparently healthy finisher pigs in North Carolina swine farms during 2009. Reverse transcription (RT)-PCR coupled hybridization assays were performed to detect known porcine NoVs. The overall prevalence of porcine NoVs determined was 18.9% based on this method. Samples were then tested by RT-PCR targeting the 5' end of the capsid region for genogroup II (GII) NoVs, a group which includes human NoVs, followed by sequence analysis. All NoVs identified belonged to typical porcine NoV genotypes, and no human NoV-like strains were detected in specimens from these pigs. Porcine NoV-negative samples (n = 335) were subsequently screened using universal calicivirus primers, and 17 SaV strains were confirmed by sequencing. Based on the partial RNA-dependent RNA polymerase (RdRp) region, they clustered with GIII, GVII, and GVIII and with currently unclassified SaVs. According to analysis of the complete capsid sequences, 7 representative strains clustered with GVII, GVIII, and GIX? SaVs. We tentatively classified SaVs into 14 genogroups based on the complete capsid protein VP1. In summary, porcine NoVs and highly divergent SaVs were present in North Carolina finisher pigs.

Longitudinal study of distributions of similar antimicrobial-resistant Salmonella serovars in pigs and their environment in two distinct swine production systems.

The aim of this longitudinal study was to determine and compare the prevalences and genotypic profiles of antimicrobial-resistant (AR) Salmonella isolates from pigs reared in antimicrobial-free (ABF) and conventional production systems at farm, at slaughter, and in their environment. We collected 2,889 pig fecal and 2,122 environmental (feed, water, soil, lagoon, truck, and floor swabs) samples from 10 conventional and eight ABF longitudinal cohorts at different stages of production (farrowing, nursery, finishing) and slaughter (postevisceration, postchill, and mesenteric lymph nodes [MLN]). In addition, we collected 1,363 carcass swabs and 205 lairage and truck samples at slaughter. A total of 1,090 Salmonella isolates were recovered from the samples; these were isolated with a significantly higher prevalence in conventionally reared pigs (4.0%; n = 66) and their environment (11.7%; n = 156) than in ABF pigs (0.2%; n = 2) and their environment (0.6%; n = 5) (P < 0.001). Salmonella was isolated from all stages at slaughter, including the postchill step, in the two production systems. Salmonella prevalence was significantly higher in MLN extracted from conventional carcasses than those extracted from ABF carcasses (P < 0.001). We identified a total of 24 different serotypes, with Salmonella enterica serovar Typhimurium, Salmonella enterica serovar Anatum, Salmonella enterica serovar Infantis, and Salmonella enterica serovar Derby being predominant. The highest frequencies of antimicrobial resistance (AR) were exhibited to tetracycline (71%), sulfisoxazole (42%), and streptomycin (17%). Multidrug resistance (resistance to ≥ 3 antimicrobials; MDR) was detected in 27% (n = 254) of the Salmonella isolates from the conventional system. Our study reports a low prevalence of Salmonella in both production systems in pigs on farms, while a higher prevalence was detected among the carcasses at slaughter. The dynamics of Salmonella prevalence in pigs and carcasses were reciprocated in the farm and slaughter environment, clearly indicating an exchange of this pathogen between the pigs and their surroundings. Furthermore, the phenotypic and genotypic fingerprint profile results underscore the potential role played by environmental factors in dissemination of AR Salmonella to pigs.

Prevalence of Yersinia enterocolitica in antimicrobial-free and conventional antimicrobial use swine production.

Swine are the primary reservoir for foodborne illness associated with Yersinia enterocolitica. The use of antimicrobials in animal agriculture has been hypothesized as having a potential role in the increase in prevalence of zoonotic pathogens. The objective of this study was to compare the frequency of Y. enterocolitica fecal shedding in swine reared on farms with conventional antimicrobial use policies to farms that were antimicrobial free (ABF). Swine farms were selected from three regions in the United States. In each region, farms were categorized based on antimicrobial use policy. Fecal samples were collected from pigs on-farm within 48 h of harvest. The overall proportion of Y. enterocolitica and ail-harboring Y. enterocolitica-positive pigs was 10.9% and 4.0%, respectively. There were increased odds (odds ratio [OR] 6.8, 95% confidence interval [CI] 3.46-13.28) for a pig to be Y. enterocolitica positive if it was reared on an ABF farm as compared to a conventional farm. There was no significant association between farm antimicrobial use policy and isolation of an ail-harboring Y. enterocolitica from an individual pig (OR 1.8, 95% CI 0.90-3.61). The association of antimicrobial use policy with Y. enterocolitica shedding in feces should be interpreted cautiously, as antimicrobial use cannot be separated from other management factors (e.g., confinement or outdoor housing), which may be associated with risk of Y. enterocolitica in swine.

Enterotoxin-encoding genes in Staphylococcus spp. from bulk goat milk.

Although Staphylococcus aureus has been implicated as the main Staphylococcus species causing human food poisoning, recent studies have shown that coagulase-negative Staphylococcus could also harbor enterotoxin-encoding genes. Such organisms are often present in goat milk and are the most important mastitis-causing agents. Therefore, this study aimed to investigate the occurrence of enterotoxin-encoding genes among coagulase-positive (CoPS) and coagulase-negative (CoNS) staphylococci isolated from raw goat milk produced in the semi-arid region of Paraiba, the most important region for goat milk production in Brazil. Enterotoxin-encoding genes were screened in 74 staphylococci isolates (30 CoPS and 44 CoNS) by polymerase chain reaction targeting the genes sea, seb, sec, sed, see, seg, seh, and sei. Enterotoxin-encoding genes were found in nine (12.2%) isolates, and four different genes (sea, sec, seg, and sei) were identified amongst the isolates. The most frequent genes were seg and sei, which were often found simultaneously in 44.5% of the isolates. The gene sec was the most frequent among the classical genes, and sea was found only in one isolate. All CoPS isolates (n=7) harboring enterotoxigenic genes were identified as S. aureus. The two coagulase-negative isolates were S. haemolyticus and S. hominis subsp. hominis and they harbored sei and sec genes, respectively. A higher frequency of enterotoxin-encoding genes was observed amongst CoPS (23.3%) than CoNS (4.5%) isolates (p<0.05), reinforcing the importance of S. aureus as a potential foodborne agent. However, the potential risk posed by CoNS in goat milk should not be ignored because it has a higher occurrence in goat milk and enterotoxin-encoding genes were detected in some isolates.

Yersinia enterocolitica of porcine origin: carriage of virulence genes and genotypic diversity.

Yersinia enterocolitica is an important foodborne pathogen, and pigs are recognized as a major reservoir and potential source of pathogenic strains to humans. A total of 172 Y. enterocolitica recovered from conventional and antimicrobial-free pig production systems from different geographic regions (North Carolina, Ohio, Michigan, Wisconsin, and Iowa) were investigated to determine their pathogenic significance to humans. Phenotypic and genotypic diversity of the isolates was assessed using antibiogram, serogrouping, and amplified fragment length polymorphism (AFLP). Carriage of chromosomal and plasmid-borne virulence genes were investigated using polymerase chain reaction. A total of 12 antimicrobial resistance patterns were identified. More than two-thirds (67.4%) of Y. enterocolitica were pan-susceptible, and 27.9% were resistant against ß-lactams. The most predominant serogroup was O:3 (43%), followed by O:5 (25.6%) and O:9 (4.1%). Twenty-two of 172 (12.8%) isolates were found to carry Yersinia adhesion A (yadA), a virulence gene encoded on the Yersinia virulence plasmid. Sixty-nine (40.1%) isolates were found to carry ail gene. The ystA and ystB genes were detected in 77% and 26.2% of the strains, respectively. AFLP genotyping of isolates showed wide genotypic diversity and were grouped into nine clades with an overall genotypic similarity of 66.8-99.3%. AFLP analysis revealed that isolates from the same production system showed clonal relatedness, while more than one genotype of Y. enterocolitica circulates within a farm.

Women's empowerment and child nutrition in a context of shifting livelihoods in Eastern Oromia, Ethiopia.

Agriculture, and particularly livestock and animal source foods, has been closely linked to improvements in human nutrition. Production, income, and women's empowerment improve household food security and child nutritional outcomes in interacting ways. Khat production in Eastern Ethiopia is changing the economic and livelihood landscape for communities that have traditionally relied upon small-scale mixed agriculture and livestock production. How this shifting livelihood landscape and the empowerment of women in these communities are affecting nutritional outcomes has not been investigated. Using cross-sectional data collected during formative research for the Campylobacter Genomics and Environmental Enteric Dysfunction (CAGED) project, we developed models to examine the roles of livelihood activities, including livestock production, staple crop production, and khat production, and women's empowerment in child nutrition outcomes. Survey participants were randomly selected mothers of children aged 10-15 months from Haramaya district, Eastern Hararghe, Oromia, Ethiopia. Nested logistic regression models were performed for each nutrition outcome: children's animal source food consumption, children's dietary diversity, and child stunting, wasting, and underweight. Explanatory variables included those for livelihood (tropical livestock unit, crop production, and khat production ladder) and women's empowerment (as indicated by domains of the Women's Empowerment in Agriculture Index), and covariates including child sex, mother's age, mother's education, assets, income, and kebele. Results indicated that khat production and tropical livestock units were not significantly associated with any of the child nutrition outcomes. However, results did indicate that the odds of reporting child animal source food consumption in households where the mother was empowered in the leadership domain was 3.33 times that in households where the mother wasn't (p < 0.05). In addition, the odds of having a stunted child in households where the mother was empowered in the time domain was 2.68 times that in households where the mother wasn't (p < 0.05). The results from this study both support and complicate the existing literature on the associations between women's empowerment in agriculture and child nutrition outcomes, underscoring the important role that livelihood, contextual factors, and location may have on the complex relationship between empowerment domains and nutritional outcomes.

Antimicrobial resistance, toxinotype, and genotypic profiling of Clostridium difficile isolates of swine origin.

The occurrence of Clostridium difficile infections in patients that do not fulfill the classical risk factors prompted us to investigate new risk factors of disease. The goal of this study was to characterize strains and associated antimicrobial resistance determinants of C. difficile isolated from swine raised in Ohio and North Carolina. Genotypic approaches used include PCR detection, toxinotyping, DNA sequencing, and pulsed-field gel electrophoresis (PFGE) DNA fingerprinting. Thirty-one percent (37/119) of isolates carried both tetM and tetW genes. The ermB gene was found in 91% of isolates that were resistant to erythromycin (68/75). Eighty-five percent (521/609) of isolates were toxin gene tcdB and tcdA positive. A total of 81% (494/609) of isolates were positive for cdtB and carry a tcdC gene (a toxin gene negative regulator) with a 39-bp deletion. Overall, 88% (196/223) of pigs carry a single C. difficile strain, while 12% (27/223) of pigs carried multiple strains. To the best of our knowledge, this is the first report of individual pigs found to carry more than one strain type of C. difficile. A significant difference in toxinotype profiles in the two geographic locations was noted, with a significantly (P < 0.001) higher prevalence of toxinotype V found in North Carolina (84%; 189/224) than in Ohio (55%; 99/181). Overall, the study findings indicate that significant proportions of C. difficile in swine are toxigenic and often are associated with antimicrobial resistance genes, although they are not resistant to drugs that are used to treat C. difficile infections.