How do pig farms maintain low Salmonella prevalence: a case-control study.

Salmonella prevalence in UK pigs is amongst the highest in Europe, highlighting the need to investigate pig farms which have managed to maintain a low Salmonella seroprevalence. A total of 19 pig farms that had a consistently low (<10%) seroprevalence over 4 years (named Platinum farms) were compared against 38 randomly selected Control farms, chosen to match the same distribution of production types and geographical distribution of the Platinum farms. Each farm was visited and floor faeces and environmental samples were collected. It was shown that Control farms had a significantly higher median percentage of pooled faecal samples positive for Salmonella compared with the Platinum farms (12.1% and 0.4% for pooled faecal samples, respectively) and were more likely to have serovars of public health importance detected (S. Typhimurium/ monophasic variants or S. Enteritidis). Considering the comprehensive on-farm sampling, the identification of farms negative for Salmonella, along with the identification of those that had maintained low prevalence over a long period is important. The risk factor analyses identified pelleted feed, feed deliveries crossing farm perimeter and regular antibiotic use as associated with being a Control farm. Performance data indicated that Platinum farms were performing better for slaughter live weight than Controls. Limited assessments of available pig movement records suggested that the source of pigs was not key to Platinum status, but further study would be needed to confirm this finding. These results emphasise that maintaining very low prevalence on UK farms is achievable.

A prevalence study of Salmonella spp., Yersinia spp., Toxoplasma gondii and porcine reproductive and respiratory syndrome virus in UK pigs at slaughter.

An abattoir-based study was undertaken between January and May 2013 to estimate the prevalence of Salmonella spp. and Yersinia spp. carriage and seroprevalence of antibodies to Toxoplasma gondii and porcine reproductive and respiratory syndrome virus (PRRSv) in UK pigs at slaughter. In total, 626 pigs were sampled at 14 abattoirs that together process 80% of the annual UK pig slaughter throughput. Sampling was weighted by abattoir throughput and sampling dates and pig carcasses were randomly selected. Rectal swabs, blood samples, carcass swabs and the whole caecum, tonsils, heart and tongue were collected. Salmonella spp. was isolated from 30·5% [95% confidence interval (CI) 26·5-34·6] of caecal content samples but only 9·6% (95% CI 7·3-11·9) of carcass swabs, which was significantly lower than in a UK survey in 2006-2007. S. Typhimurium and S. 4,[5],12:i:- were the most commonly isolated serovars, followed by S. Derby and S. Bovismorbificans. The prevalence of Yersinia enterocolitica carriage in tonsils was 28·7% (95% CI 24·8-32·7) whereas carcass contamination was much lower at 1·8% (95% CI 0·7-2·8). The seroprevalence of antibodies to Toxoplasma gondii and PRRSv was 7·4% (95% CI 5·3-9·5) and 58·3% (95% CI 53·1-63·4), respectively. This study provides a comparison to previous abattoir-based prevalence surveys for Salmonella and Yersinia, and the first UK-wide seroprevalence estimates for antibodies to Toxoplasma and PRRSv in pigs at slaughter.

Cross-sectional survey of antibiotic resistance in Escherichia coli isolated from diseased farm livestock in England and Wales.

Between 2005 and 2007, E. coli obtained from clinical diagnostic submissions from cattle, goats, pigs and sheep to government laboratories in England and Wales were tested for sensitivity to 16 antimicrobials. Resistance was most commonly observed against ampicillin, streptomycin, sulphonamides and tetracyclines. Resistance levels varied significantly between species, with isolates from cattle frequently showing the highest levels. Verocytotoxigenic E. coli (VTEC) expressed less resistance than non-VTEC. Only 19·3% of non-VTEC and 43·5% of VTEC were susceptible to all antimicrobials, while 47·1% and 30·4%, respectively, were resistant to ⩾5 antimicrobials. The resistance phenotype SSuT was commonly observed, and isolates resistant to third-generation cephalosporins were also identified. We recommend judicious antimicrobial usage in the livestock industry in order to preserve efficacy.

Prevalence of extended-spectrum-ß-lactamase-producing Escherichia coli from pigs at slaughter in the UK in 2013.

OBJECTIVES: To determine the prevalence and types of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli occurring in pigs at slaughter in the UK in 2013. METHODS: Caecal samples from 637 pigs, sampled via a UK-wide monitoring programme in 2013, were enriched overnight in buffered peptone water, before plating to CHROMagar CTX and Oxoid Brilliance ESBL agar. Presumptive ESBL-producing E. coli from both media were tested for ESBL phenotype using MAST ESßL ID discs. Isolates with an ESBL phenotype were examined for the presence of blaCTX-M, blaOXA, blaSHV and blaTEM genes using a multiplex PCR. All blaCTX-M and blaSHV genes identified by PCR were sequenced. RESULTS: A total of 23.4% (95% CI 19.2-27.6) of pigs were positive for ESBL-producing E. coli; 22% (95% CI 17.8-26.1) of the pigs carried E. coli producing CTX-M enzymes [comprising enzyme types 1 (18.7% of pigs), 3 (0.2%), 14 (0.5%), 15 (1.4%), 27 (0.5%), 32 (0.5%) and 55 (0.3%)] and 2.2% (95% CI 0.8-3.6) of the pigs carried E. coli producing SHV-12. Five pigs carried both CTX-M- and SHV-12-producing E. coli as different isolates. There were no statistically significant differences observed between the two medium types in terms of the proportions of each CTX-M enzyme type isolated. CONCLUSIONS: In this UK study, 23.4% of pigs were found to be positive for ESBL-producing E. coli using selective culture media. The use of two different commercially available ESBL isolation media was found to improve the detection of ESBL-producing E. coli.

Prevalence and molecular typing of Cryptosporidium in dairy cattle in England and Wales and examination of potential on-farm transmission routes.

An average of 70 samples were collected from 80 dairy farms in England and Wales, from cattle, co-grazed sheep, wildlife and farm wastes, to investigate prevalence, potential sources and transmission routes of Cryptosporidium. At least one positive sample was detected on 74 of the farms (92.5%) by IFAT microscopy. The prevalence in cattle was 10.2% (95% CI 9.4-11.1%), with greater prevalences detected in calf samples, especially from those under 1 month (45.1%). Young calves were also more likely to be shedding Cryptosporidium parvum and larger concentrations of oocysts, whereas older calves and adult cattle were more likely to be shedding Cryptosporidium bovis and Cryptosporidium andersoni, respectively. The C. parvum subtypes detected were predominantly from types commonly identified in UK cattle (67% were either IIaA15G2R1 or IIaA17G1R1). A novel subtype, IIaA17G1R2, was identified from one cattle sample. The prevalence in co-grazed sheep was low (4%). Birds and rodents may represent significant reservoirs of Cryptosporidium due to high prevalence, large oocyst concentrations, and the detection of a C. parvum subtype known to be present in human populations, identified in samples from these wildlife. Cryptosporidium were detected in dirty water and manure, and also from pasture samples where slurry had been spread. On 64% of the farms, identical Cryptosporidium species were detected (mainly C. parvum or C. bovis) from different cattle groups on the farms, although no direct or indirect contact between the groups were recorded, apart from sharing staff. The same Cryptosporidium species were found in cattle, farm wastes and bird samples on the same farms, but rarely, or not at all, present in sheep or rodent samples. The matching of species/subtypes was also related to the proximity of the different sample sources which may indicate a potential transmission route.

Risk factors associated with extended spectrum beta-lactamase Escherichia coli (CTX-M) on dairy farms in North West England and North Wales.

This study investigated the potential spread of CTX-M-14 Escherichia coli from a known ESBL E. coli positive farm and risk factors for the presence of CTX-M E. coli on dairy farms. Between November 2009 and March 2010, 65 farms in North West England and North Wales were visited and animals sampled for E. coli producing CTX-M ESBLs. Seventeen of these were known to have received animals from a known ESBL E. coli positive 'index' farm since 2005 (linked farms). The prevalence of CTX-M E. coli in the population of linked farms was 58.8% (10/17; CI(95%) 32.9-81.6%) and in the randomly selected control population was 35.4% (17/48; CI(95%) 22.2-50.5%). There was no significant (p>0.05) linkage for the detection of any CTX-M E. coli or specifically a CTX-M-14 E. coli to the index farm. Group 1 (CTX-M-15, CTX-M-55, CTX-M-1, CTX-M-32), group 2 (CTX-M-2) and group 9 (CTX-M-14, CTX-M-14 B, CTX-M-27) CTX-M E. coli were identified on the study farms. Molecular analysis revealed that three plasmids from linked farms had similar sizes (95 kbp), replicon type (IncK) and backbone genes as that from the index farm. Logistic regression analysis revealed that farms that had used a 3rd or 4th generation cephalosporin (ceftiofur, cefoperazone and cefquinome) in livestock in the last 12 months were nearly 4 times more likely to have ESBL E. coli present (p=0.037; OR=3.93). There was no significant association between presence of CTX-M E. coli and the use of any 1st or 2nd generation cephalosporins. Several other risk factors for the presence of CTX-M E. coli were identified, such as storage of slurry in a pit, operating an open herd policy and infrequent cleaning of calf feeding equipment.

Verocytotoxin-producing and attaching and effacing activity of Escherichia coli isolated from diseased farm livestock.

Between May 2005 and June 2008, strategically selected isolates of Escherichia coli obtained from clinical submissions to Veterinary Laboratories Agency (VLA) regional laboratories in England and Wales were serogrouped and examined by PCR for verocytotoxin (VT) production and attaching and effacing (eae) genes, both of which are zoonotic determinants. VT-encoding genes were detected in 54 (5.3 per cent) of the 1022 isolates examined. Only one isolate (0.1 per cent) was identified as verocytotoxigenic E coli (VTEC) O157. Non-O157 VTECs were present in 4.7 per cent of isolates from cattle, compared with 7.9 per cent in pigs, 2.3 per cent in sheep and 6.7 per cent in goats. The predominant serogroup identified in cattle was O26 and the predominant serogroup in pigs was O2. Attaching and effacing activity was attributed to 69 (6.8 per cent) of all isolates.

A qualitative study of women in polygynous marriages.

UNLABELLED: Polygyny, the practice of taking more than one wife at the same time is a common practice in several countries including Africa. This study, conducted in Ghana, West Africa, investigated married women's experiences in polygyny and their ways of coping. METHODS: Using exploratory qualitative methodology, data were collected from 15 married women who consented to in-depth interviews. The study was conducted in the summer of 2005 with approval from an institutional review board and permission from community leaders from the study site. FINDINGS: Three themes emerged from the study: infertility, co-wives' relationships and ways of coping. The findings indicated that infertility was the number one reason that women allowed for co-wives in their marriages because this was necessary to protect the marriage rather than divorce. Unhappiness, loneliness, sense of competition and jealousy, and lack of intimacy with the spouse were identified as disadvantages of polygyny. The perceived advantages of polygyny included sharing of house chores and child rearing. The women's ways of coping included the use of religion, faith and a strong sisterly bond formed with the co-wives. Though the majority of the women disapproved of polygyny unions, divorce was not an option. CONCLUSION: These findings have implications for nursing and policy-makers. Nurses can provide education and implement programmes that teach coping mechanisms and stress management. Policy-makers should be made aware of the implications of polygynous marriages on women's health and well-being. There is the need to conduct more research to investigate the effects of polygyny on women's mental health and the need to develop programmes to support women.