Antimicrobial resistance (AMR) is one of the top global health threats of the 21th century. Recent studies are increasingly reporting the rise in extended-spectrum beta-lactamases producing Enterobacteriaceae (ESBLs-Ent) in dairy cattle and humans in the USA. The causes of the increased prevalence of ESBLs-Ent infections in humans and commensal ESBLs-Ent in dairy cattle farms are mostly unknown. However, the extensive use of beta-lactam antibiotics, especially third-generation cephalosporins (3GCs) in dairy farms and human health, can be implicated as a major driver for the rise in ESBLs-Ent. The rise in ESBLs-Ent, particularly ESBLs-Escherichia coli and ESBLs-Klebsiella species in the USA dairy cattle is not only an animal health issue but also a serious public health concern. The ESBLs-E. coli and -Klebsiella spp. can be transmitted to humans through direct contact with carrier animals or indirectly through the food chain or via the environment. The USA Centers for Disease Control and Prevention reports also showed continuous increase in community-associated human infections caused by ESBLs-Ent. Some studies attributed the elevated prevalence of ESBLs-Ent infections in humans to the frequent use of 3GCs in dairy farms. However, the status of ESBLs-Ent in dairy cattle and their contribution to human infections caused by ESBLs-producing enteric bacteria in the USA is the subject of further study. The aims of this review are to give in-depth insights into the status of ESBL-Ent in the USA dairy farms and its implication for public health and to highlight some critical research gaps that need to be addressed.

Salmonella is the most important causes of foodborne illness especially from poultry and poultry products. So the aim of this study was to carryout phenotypic characterization, antimicrobials susceptibility pattern and risk factors of Salmonella isolates from farms and markets eggs, cloacae swabs of chickens and stool of egg collectors. A cross-sectional study was conducted from January 2018 to September 2018. Samples were, processed; Salmonella was isolated, phenotypically identified by OmniLog and antimicrobials susceptibility were carried out. Over all; 11 (2.65%) of Salmonella enterica were phenotypically characterized out of 415 samples from farms egg content (n = 83), farms eggshell (n = 83), cloacae (n = 83), market eggshell (n = 83) and market egg contents (n = 83) with 2.4%, 0%, 2.4%, 4.8% and 3.6% prevalence, respectively. Out of isolates, 8 (72.72%) displayed multidrug resistance. All isolates showed susceptibility to Gentamicin, Kanamycin and Streptomycin. Lack of separating cracked eggs, washing hand, eggs stay longer unsold, and mixing excreta with feed were associated risk factors for Salmonella presence (P-value < 0.05). The presence of drug resistant Salmonella enterica within egg/and chicken can pose serious health problem. Good hygienic practices are important to reduce risk factors of Salmonella contamination.

Mycobacterium bovis (M. bovis) has an exceptionally wide host range including sheep. Information on tuberculosis (TB) in sheep is scarce, and there appears to be conflicting opinions about the relative susceptibility of sheep to infection. In Ethiopia, there was no single previous report on tuberculosis in sheep, though mixed farming of cattle and sheep is a common practice. In this study, following the observation of TB-like lesions on sheep died from sheep flock kept in contact with cattle herd, further investigation was conducted on the flock to assess the magnitude of the infection and identify and characterize the causative M. bovis strain. An outbreak investigation was carried out on 26 eligible sheep out of 33 sheep found on the farm. Comparative intradermal tuberculin (CIDT) test, postmortem examination, Mycobacterium culturing, and spoligotyping were the techniques used in the study. The prevalence of TB in the tested sheep was 15% (4/26). All the sheep that were positive to CIDT had gross lesions suggestive of TB. Three of the positive sheep had extensive and multiple lesions. M. bovis was isolated from all four sheep and the strain was identified as spoligotype SBO134. The in-contact dairy cows were screened for TB and 98% (45/46) of the cows tested positive to CIDT. Furthermore, the same strain, SB0134, was also isolated from the two in-contact cows. The isolation of a matching genotype (SB0134) of M. bovis from both species sharing a known epidemiologic link strongly suggests that the sheep flock might have acquired the pathogen from the dairy cows. This warrants strict physical separation of the sheep flock from the cattle herd to prevent such interspecies transmission of M. bovis.

Blackleg is one of the major bacterial infections causing tremendous economic losses to cattle herders in many parts of Ethiopia. Despite the huge burden, no comprehensive studies have quantified the impact or its distribution throughout the country. This study was aimed to estimate the epidemiological aspect of blackleg, financial costs and benefits of its control through annual vaccination on small holder cattle herders in Southern Ethiopia. Annual financial cost due to blackleg was calculated as the sum of production losses due to mortality, morbidity, treatment and vaccination costs at herd level. Production loss due to the disease was estimated and compared between local zebu and crossbred cattle. Partial budget analysis was used to estimate financial benefit of control intervention through annual vaccination. An overall cumulative incidence and mortality rate of blackleg in local zebu cattle population was 17.9 % (95 % CI 16.5–19.4) and 3.6 % (95 % CI 2.9–4.4 %) respectively. Cumulative incidence and mortality rate attributed to blackleg in crossbreds cattle was 19 % (95 % CI 16.9–21.6) and 3.9 % (95 % CI 2.9–5.3 %) respectively. There was no statistically significant difference (p > 0.05) in both variables between the two breeds. Financial costs in blackleg infected herds was estimated to be USD 9.8 (95 % CI 6.7–14.4) per head for local zebu and USD 16 (95 % CI 10–24.4) per head for crossbred cattle. The marginal rate of return that could be obtained from the control intervention was estimated to be 9 (900 %) and the net benefit per head was USD 0.4 for local zebu and USD 0.8 for crossbred cattle. Vaccination, therefore, reduces financial losses due to blackleg by 3.4 and 6.9 % per head in local zebu and crossbred cattle herds respectively. The present study revealed considerable financial losses due to blackleg occurrence. The information obtained would be helpful to improve the farmers’ livelihood and may open new avenues of research for the eradication and control of the disease at local and national level.

Klebsiella species commonly reside in dairy cattle guts and are consistently exposed to beta-lactam antibiotics, including ceftiofur, which are frequently used on the U.S. dairy farms. This may impose selection pressure and result in the emergence of extended-spectrum beta-lactamase (ESBL)-producing strains. However, information on the status and antimicrobial resistance (AMR) profile of ESBL- Klebsiella spp. in the U.S. dairy farms is largely unknown. This study aimed to determine the prevalence and AMR profile of ESBL- Klebsiella spp. and the factors affecting their occurrence in dairy cattle farms. Rectal fecal samples ( n = 508) and manure, feed, and water samples ( n = 64) were collected from 14 dairy farms in Tennessee. Samples were directly plated on CHROMagar ESBL, and presumptive Klebsiella spp. were confirmed using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Antimicrobial susceptibility testing was performed on the isolates against panels of 14 antimicrobial agents from 10 classes using minimum inhibitory concentration. Of 572 samples, 57 (10%) were positive for ESBL- Klebsiella spp. The fecal prevalence of ESBL- Klebsiella spp. was 7.2% (95% CI: 6.5–8.0). The herd-level fecal prevalence of ESBL- Klebsiella spp. was 35.7% (95% CI: 12.7–64.8). The fecal prevalence of ESBL- Klebsiella spp. was significantly higher in calves than in cows and higher in cows with higher parity (≥3) as compared to cows with low parity ( P < 0.001). Most (96.5%, n = 57) ESBL- Klebsiella spp. were resistant to ceftriaxone. The highest level of acquired co-resistance to ceftriaxone in ESBL- Klebsiella spp. was to sulfisoxazole (66.7%; 38/57). About 19% of ESBL-K lebsiella spp. were multidrug resistant. The presence of ESBL-producing Klebsiella spp. in dairy cattle, feed, and water obtained from troughs could play a crucial epidemiological role in maintaining and spreading the bacteria on farms and serving as a point source of transmission. IMPORTANCE: We collected 572 samples from dairy farms, including rectal feces, manure, feed, and water. We isolated and identified extended-spectrum beta-lactamase (ESBL)- Klebsiella spp. and conducted an antimicrobial susceptibility test and analyzed different variables that may be associated with ESBL- Klebsiella spp. in dairy farms. The results of our study shed light on how ESBL- Klebsiella spp. are maintained through fecal-oral routes in dairy farms and possibly exit from the farm into the environment. We determine the prevalence of ESBL- Klebsiella spp. and their antimicrobial susceptibility profiles, underscoring their potential as a vehicle for multiple resistance gene dissemination within dairy farm settings. We also collected data on variables affecting their occurrence and spread in dairy farms. These findings have significant implications in determining sources of community-acquired ESBL- Enterobacteriaceae infections and designing appropriate control measures to prevent their spread from food animal production systems to humans, animals, and environments.

Q fever is a zoonotic disease that is caused by Coxiella burnetii and leads to abortion and infertility in ruminants and debilitating disease in humans. Jimma zone, including Jimma town, located in the Oromia region of Ethiopia, was affected by an outbreak of abortions in ruminants related to Q fever infection between 2013 and 2015. This study aimed to investigate the geo-clustering of C. burnetii seroprevalence in dairy farms of Jimma town and identify the environmental risk factors associated with seroprevalence distribution. A total of 227 cattle were tested for antibodies against C. burnetii in 25 farms. We explored the clustering of C. burnetii seroprevalence using semivariograms. A geostatistical regression-based model was implemented to quantify the risk factors and to predict the geographical variation in C. burnetii seroprevalence at unsampled locations in Jimma town using OpenBugs. Our results demonstrated that the risk of exposure in dairy cattle varied across the landscape of Jimma town and was associated with environmental risk factors. The predictive map of C. burnetii seroprevalence showed that communities in the eastern part of Jimma town had the highest risk of exposure. Our results can inform community-level investigations of human seroprevalence in the high-risk areas to the east of Jimma.