Epidemiology of camel contagious ecthyma and molecular detection of the pathogen in Arero district, Ethiopia

Even though camels (Camelus dromedarius) were traditionally believed to be resistant to most livestock diseases, research has demonstrated that they are susceptible to a large number of infectious agents. Based on the clinical appearance of typical lesions, camel contagious ecthyma (CCE), caused by a Parapoxvirus (PPV), is thought to be one of the most common viral diseases of camels in Ethiopia. A cross-sectional study was conducted from November 2013 to April 2014 in the Arero district of Borena Zone, Oromia Regional State of Ethiopia to investigate the epidemiological aspect of CCE and molecularly identify the causative agent. A polymerase chain reaction (PCR) based on B2L gene-specific primers of PPV was used for the confirmatory diagnosis of the CCE virus from the skin lesion of camels showing suspected clinical signs of CCE infection. Eighty-seven percent (87.0%) of camel owners reported the occurrence of CCE outbreaks in their herds in the past year (a year preceding the start of the study). The overall morbidity and mortality rates attributed to CCE were 20% (95% CI: 11– 36%) and 6.3% (95 % CI: 5.2 –7.6%), respectively. Younger camels had higher odds of becoming affected by CCE than adults [OR=3.44 (95 % CI: 2.29 –4.09)] and the difference was statistically significant. Confirmatory diagnosis of the suspected cases using conventional PCR generated the expected amplification product size of 1200bp for one of the samples. Therefore, the study confirms the presence and importance of CCE in Ethiopia and establishes the basis for further investigation

Antimicrobial Resistance and Molecular Epidemiology of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella Species in Dairy Farms

Extended-spectrum beta-lactamase (ESBL)-producing-E. coli and -Klebsiella species present major global health threats. However, there is limited information on the status and genomic epidemiology of these bacteria in the United States conventional dairy cattle farms that frequently use beta-lactam antibiotics. This dissertation is aimed to determine the prevalence, antimicrobial resistance, spread mechanisms, and public health implication of ESBL-E. coli and -Klebsiella spp. using microbiological and molecular tools. A total of 605 samples (rectal feces, bulk tank milk (BTM), manure, water, and feed) were tested. From these, 241 ESBL-E. coli and 59 ESBL-Klebsiella spp. were detected. The prevalence of fecal ESBL-E. coli and -Klebsiella spp. were 47.5% (n=508) and 7.2 % (n=508), respectively. Most E. coli isolates (94.4%, n=241) were multidrug-resistant (MDR), whereas only 19% (n=57) ESBL-Klebsiella spp. were MDR. Six families of beta-lactamase (bla) genes, along with several other resistance genes (ARGs), were detected in both E. coli and Klebsiella spp. The blaCTX-M and blaTEM were the most frequent in E. coli, whereas blaSHV and blaCTX-M were dominant in ESBL-Klebsiella spp. A 47 distinct sequence types (STs), 13 unknown, and 4 novel STs of ESBL-E. coli and 15 distinct STs, and 10 unknown STs of ESBL-K. pneumoniae were identified. High-risk E. coli clones accounted for 28% (n=67) of the identified STs. Both ESBL-E. coli and -K. pneumoniae STs were clustered within farms, suggesting animal-to-animal transmission. Evidence of horizontal spread of bla genes via plasmid was also observed. ESBL-E. coli and -Klebsiella spp. were detected in 24.2% and 6.1 % of BTM, respectively. About 41% of dairy farms had ESBL-E. coli in their BTM. All ESBL-E. coli isolates from BTM were MDR and co-carried the blaCTX-M, other ARGs, and several virulence genes. Isolates with matching STs and resistance patterns were detected in BTM, and fecal samples collected from the same farm. Four ESBL-E. coli STs obtained from BTM were high-risk pandemic clones. MDR ESBL-E. coli, including high risk-clones, and ESBL-Klebsiella spp. were widespread in dairy farms and BTM. These findings indicate that dairy cattle can serve as a reservoir for zoonotic ESBL-E. coli and -K. pneumonia

Extended-Spectrum Beta-Lactamases Producing <i>Enterobacteriaceae</i> in the USA Dairy Cattle Farms and Implications for Public Health

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