Whole genome sequence analysis of the 2018 Persian onager isolate suggests sublineages within the Taylorella asinigenitalis species.

In 2018, a T. asinigenitalis strain (MCE663) was isolated in a Persian onager tested for contagious equine metritis (CEM) in a United Kingdom (UK) zoo. This bacterium had never been reported in the UK and Multilocus Sequence Typing described a new atypically divergent ST (ST60). Although the causative agent of CEM is the bacterium Taylorella equigenitalis, a first natural outbreak of endometritis caused by T. asinigenitalis ST70 was reported in 2019, putting its pathogenic potential into question. In this context, we aimed to further sequence the T. asinigenitalis MCE663 genome and characterize the strain using phenotypical and genetic approaches. Results showed that it gathered all identification characteristics of T. asinigenitalis with smaller colonies and it was susceptible to all tested antibiotics. Genome-level phylogeny showed that the genome MCE663 formed a distinct phylogroup, and only shared ≈ 96.1% of average nucleotide identity (ANI) with the three published T. asinigenitalis genomes, which together shared ≈ 98.3% ANI. According to current cut-offs consensus for species and subspecies delineation (95% and 98%, respectively), our results support the first insights of a sublineage delineation within the T. asinigenitalis species.

Enhanced detection of Taylorella equigenitalis by qPCR using 'Dry' swabs.

Detection of Taylorella equigenitalis (CEMO) in the horse uses genital swabs. These swabs traditionally have been put in Amies charcoal transport medium for detection by culture but are also used for PCR. We determined the suitability of swabs without transport medium (Dry swabs) for CEMO PCR compared to swabs in Amies charcoal transport medium. The experiment was a factorial design using swab type and dilution of organism in culture suspensions, done in two parts. Simulated genital swabs were prepared in the laboratory by dipping in pairs into culture suspensions containing T. equigenitalis with or without other organisms, and then inserting them into a sleeve either with or without transport medium. In study 1, the difference in Ct value for the two swab types was compared. In study 2 genital swab material was then also added to culture suspensions and the swab types again compared. The swabs were tested by a validated quantitative PCR method. The Ct value of the PCR test was used as the measure for comparison, and the effect of variables assessed with linear regression. There was an 7.7% (6.5-8.9) higher mean Ct value of TM versus Dry swabs (P<0.001) overall. The Ct difference was more marked at higher dilutions. Addition of genital swab material had no effect on the Ct value. Dry swabs perform at least as well for PCR as swabs in Amies charcoal transport medium, especially when relatively low numbers of organism are present, and are advantageous for routine sampling when culture is not being used.

Screening for Taylorella equigenitalis in Equine Semen: An Exploratory Study.

The study examined and compared the sensitivity of culture and a quantitative PCR assay for screening equine semen for the presence of Taylorella equigenitalis (CEMO). Chilled semen samples, both raw and treated with extender, from two stallions were spiked with the organism at seven or 23 days postejaculation and prepared in serial dilutions. Culture of the 7-day raw semen readily detected CEMO at all dilutions, but extended semen yielded counts that were two log cycles lower at equivalent dilutions, with the organism being nearly undetectable at the maximal dilutions. By contrast, PCR sensitivity was not affected by extender, but for 7-day-old raw semen, PCR detection declined abruptly three log dilutions earlier than detection by culture. The more aged 23-day-old semen proved less satisfactory for spiking, with detection of CEMO by culture failing in three of the four samples due to overgrowth with commensal organisms. However, PCR performance was similar in both the 23- and 7-day spiking series. The detection limit by PCR is estimated at between 104 and 105 cfu/mL. Typical CEMO concentrations in the semen of colonized stallions are not widely reported but where natural semen contamination has been investigated, the organism was present at this order of magnitude. The reliability of detecting CEMO infection using semen samples by either method is discussed.

Control of Salmonella and Pathogenic E. coli Contamination of Animal Feed Using Alternatives to Formaldehyde-Based Treatments.

This study compared a novel non-formaldehyde combination product developed for pathogen control in animal feed Finio (A), with a panel of three commonly used organic acid feed additive products: Fysal (B), SalCURB K2 (C) and Salgard (D). Products were evaluated for their ability to reduce Salmonella Typhimurium DT104 and avian pathogenic Escherichia coli in poultry feed. A commercial layer-hen mash was treated with each product and then mixed with feed previously contaminated (via inoculated meat and bone meal) with either Salmonella or E. coli. After 24 hours at room temperature, 10 replicate samples were taken from each preparation and plate counts were performed using a selective agar. All concentrations of product A (0.5, 1.0, 1.5, 2.0 and 2.5 kg per metric tonne (MT)) plus the higher concentration of products B and D (6.0 kg MT-1) significantly reduced Salmonella counts compared with those in the untreated control group (p < 0.05). Product C did not significantly reduce levels of Salmonella under these conditions. Because of the poor recovery of E. coli, statistical comparisons for this organism were limited in scope, but only product A at the highest concentration appeared to have eliminated it.

A new strain of Taylorella asinigenitalis shows differing pathogenicity in mares and Jenny donkeys.

BACKGROUND: Three horse mares inadvertently inseminated with semen from a Tayorella asinigenitalis-positive Jack donkey developed severe, purulent endometritis whereas two Jenny donkeys mated naturally to the same Jack donkey did not develop clinical signs of infection. OBJECTIVES: To isolate and identify the causative agent. STUDY DESIGN: Case report. METHODS: Endometrial swabs from the infected mares were cultured on selective and non-selective media under aerobic and microaerophilic conditions. Isolates were subjected to Gram staining, oxidase and catalase tests, the Monotayl Latex Agglutination test and PCR to test for both T. equigenitalis and T. asinigenitalis. In vitro antimicrobial susceptibility testing was performed and the bacterial isolate was genotyped using MLST. RESULTS: A new sequence type of T. asinigenitalis was confirmed. MAIN LIMITATIONS: A limited numbers of mares and donkeys are described. CONCLUSIONS: This strain of T. asinigenitalis causes a severe venereal infection in mares but not in Jenny donkeys.

Efficacy of disinfectants and detergents intended for a pig farm environment where Salmonella is present.

Disinfection is a useful component of disease control, although products and chemical groups vary in their activity against different pathogens. This study investigated the ability of fifteen disinfectants to eliminate pig-associated Salmonella. Active compounds of products included chlorocresol, glutaraldehyde/formaldehyde, glutaraldehyde/quaternary ammonium compounds (QAC), iodine, peracetic acid and potassium peroxomonosulphate. Six detergents were also tested for their ability to dislodge faecal material, and interactions with specific disinfectants. Eight serovars were screened against all products using dilution tests and a monophasic Salmonella Typhimurium strain was selected for further testing. The disinfectants were tested using models to replicate boot dip (faecal suspension) and animal housing (surface contamination) disinfection respectively at the Department for Environment, Food and Rural Affairs Approved Disinfectant General Orders (GO) concentration, half GO and twice GO. Stability over time and ability to eliminate Salmonella in biofilm was also assessed. The most effective products were then field tested. Most products at GO concentration eliminated Salmonella in the faecal suspension model. One glutaraldehyde/QAC and one glutaraldehyde/formaldehyde-based product at GO concentration eliminated Salmonella in the surface contamination model. Chlorocresol-based products were more stable in the faecal suspension model. One chlorocresol and the glutaraldehyde/formaldehyde-based product were most successful in eliminating Salmonella from biofilms. All products tested on farm reduced bacterial log counts; the glutaraldehyde/QAC based product produced the greatest reduction. The type of product and the application concentration can impact on efficacy of farm disinfection; therefore, clearer guidance is needed to ensure the appropriate programmes are used for specific environments.

Evaluation of lateral flow devices for identification of infected poultry by testing swab and feather specimens during H5N1 highly pathogenic avian influenza outbreaks in Vietnam.

BACKGROUND: Evaluation of two commercial lateral flow devices (LFDs) for avian influenza (AI) detection in H5N1 highly pathogenic AI infected poultry in Vietnam. OBJECTIVES: Determine sensitivity and specificity of the LFDs relative to a validated highly sensitive H5 RRT PCR. METHODS: Swabs (cloacal and tracheal) and feathers were collected from 46 chickens and 48 ducks (282 clinical specimens) and tested by both LFDs and H5 RRT PCR. A subset of 59 chicken and 34 duck specimens was also tested by virus isolation (VI), the 'gold standard'. RESULTS: Twenty-six chickens and 15 ducks were shown to be infected by at least one RRT PCR positive clinical specimen per bird. Bird-level sensitivity for the Anigen LFD was 84·6% for chickens and 53·3% for ducks, and for the Quickvue LFD 65·4% for chickens and 33·3% for ducks. Comparison of the three clinical specimens revealed that chicken feathers were the most sensitive with 84% and 56% sensitivities for Anigen and Quickvue respectively. All 21 RRT PCR positive swabs from ducks were negative by both LFDs. However, duck feather testing gave sensitivities of 53·3% and 33·3% for Anigen and Quickvue respectively. Specificity was 100% for both LFDs in all investigations. CONCLUSIONS: Although LFDs were less sensitive than AI RRT PCR and VI, high titre viral shedding in H5N1 highly pathogenic avian influenza (HPAI) infected and diseased chickens is sufficient for a proportion of birds to be identified as AI infected by LFDs. Feathers were the optimal specimen for LFD testing in such diseased HPAI scenarios, particularly for ducks where swab testing by LFDs failed to identify any infected birds. However, specimens should be forwarded to the laboratory for confirmation by more sensitive diagnostic techniques.