Associations between a decreased veterinary antimicrobial use and resistance in commensal Escherichia coli from Belgian livestock species (2011-2015).

In this study the possible association between antibiotic use and resistance was explored, focusing on commensal Escherichia coli from livestock (veal calves, young beef cattle, pigs and broiler chickens) in Belgium between 2011 and 2015. A continuous decreasing trend in antibiotic use was observed for all classes, except for the phenicols. Antibiotic resistance of commensal E. coli significantly decreased for several of the tested antibiotics in all livestock species. A more rapidly reverted resistance was seen to 3th/4th generation cephalosporins and fluoroquinolones. Moderate to strong correlations between antibiotic use and resistance were found, except for antibiotic resistance to chloramphenicol and gentamicin and the use of the corresponding antibiotic class. Yet, total antibiotic use was positively correlated with chloramphenicol resistance, showing the potential importance of co-selection for chloramphenicol resistance. These results suggest that national antimicrobial usage reduction campaigns have beneficial effects on the overall resistance levels. Analyses were performed on small datasets, though, and care must be taken while making inference. For more detailed analysis, antibiotic use data at an animal species level are required.

Detection of Plasmid-Mediated Colistin Resistance, mcr-1 and mcr-2 Genes, in Salmonella spp. Isolated from Food at Retail in Belgium from 2012 to 2015.

A collection of 105 colistin-resistant Salmonella isolates collected from 2012 to 2015 in the national surveillance program in Belgium was screened by PCR for the presence of genes mcr-1 and mcr-2. Of these, 1.90% (2/105) and 0.95% (1/105) tested positive for mcr-1 and mcr-2, respectively. The presence of the mcr-1 or mcr-2 determinant has been confirmed by whole genome sequencing and allowed the localization of these two genes on IncX4 type plasmids. We report here the presence of mcr-1 and the first mcr-2 gene in Salmonella ever isolated in the Belgian food chain. Although present at retail since 2012, the occurrence is low and sporadic.

A trend analysis of antimicrobial resistance in commensal Escherichia coli from several livestock species in Belgium (2011-2014).

A temporal trend analysis was performed on antimicrobial resistance data collected over 4 consecutive years (2011-2014) in the official Belgian antimicrobial resistance monitoring programme. Commensal Escherichia coli strains were isolated from faecal samples of four livestock categories (veal calves, young beef cattle, broiler chickens and slaughter pigs) and the trends of resistance profiles were analysed. The resistance prevalence remained high (>50%) during the study period for ampicillin in veal calves and chickens, for ciprofloxacin and nalidixic acid in chickens, for sulfamethoxazole in veal calves, chickens and pigs and for tetracycline in veal calves. Using logistic regression and Generalized Estimating Equation and after p value adjustment for multiple testing (Linear step-up method), statistically significant decreasing temporal trends were observed for several of the 11 tested antimicrobials in several livestock categories: in veal calves (10/11), in chickens (6/11) and in pigs (5/11). A significant increasing trend was observed for the prevalence of resistance to ciprofloxacin in chickens. Multi-resistance, considered as the resistance to at least three antimicrobials of different antibiotic classes, was observed in the four livestock categories but was significantly decreasing in veal calves, chickens and pigs. Overall, the prevalence of resistance and of multi-resistance was lowest in the beef cattle livestock category and highest in broiler chickens. These decreasing temporal trends of antimicrobial resistance might be due to a decrease of the total antimicrobial consumption for veterinary use in Belgium which was reported for the period between 2010 and 2013. The methodology and statistical tools developed in this study provide outputs which can detect shifts in resistance levels or resistance trends associated with particular antimicrobial classes and livestock categories. Such outputs can be used as objective evidence to evaluate the possible efficacy of measures taken by animal health authorities and stakeholders in the livestock sector to limit antimicrobial resistance occurrence.

Evaluation of the Salmonella surveillance program in Belgian pig farms.

Since July 2007, Belgium has implemented a national surveillance and control program for Salmonella in pigs. Pig farms are designated as Salmonella high risk farms based on serological profiles and are obliged to subsequently take part in a Salmonella specific action plan (SSAP). The SSAP was evaluated and potential risk factors for the persistence of Salmonella on the farm were investigated. First, the Kaplan-Meier method was used in order to study the period during which a farm maintains a Salmonella high risk status. Farms recovered more slowly from their high risk status before the SSAP was implemented compared to after the program was implemented (p<0.001). However, results showed that 29% of the farms were withdrawn from the program possibly only because of sampling error. The program should thus be adapted to accommodate for this. Secondly, the influence of several risk factors (type of farm, season of entrance into the SSAP, size of farm and farm density of the municipality) on the time to withdrawal from the high risk status was evaluated using univariable methods and a Cox multiple regression model for survival data. A statistically significant association was identified between the type of farm and the time to withdrawal from the high risk status. At any point in time after the onset of the SSAP, withdrawals from the high risk status occurred at a 39% and 28% higher rate in mixed (p=0.01) and fattening farms (p=0.05), respectively, compared to closed farms. The risk attributed to closed pig farms is related to the presence of sows in this particular type of structure, which underlines the importance of implementing control measures in this category of animals.

Identification of risk factors for the prevalence and persistence of Salmonella in Belgian broiler chicken flocks.

According to the European Food Safety Authority, salmonellosis is still one of the main causes of infectious foodborne gastroenteritis in humans. Broilers are an important source of salmonellosis after eggs and pork. Between 1987 and 1999 the trend of human salmonellosis incidence in Belgium increased constantly. However, from 2000 until 2005 a decrease in human cases was observed, probably following the sanitary measures implemented in the poultry breeder and laying sector. In order to decrease human infections it is essential to tackle the problem at the farm level to minimize cross-contamination from farm to fork. This paper seeks to answer two questions: (i) given the Salmonella status of the farm at a certain occasion (equal to the sampling time of the flock), what are the risk factors that the farm will be Salmonella positive at a following occasion? And (ii) what are the risk factors for a farm to be persistently positive for two consecutive flocks? We used surveillance data on 6824 broiler flocks studied for Salmonella infectivity from 2005 to 2006 in Belgium. The farms were tested regularly (3 weeks before slaughter of each broiler flock) for the presence of Salmonella based on multiple faecal samples per flock on a farm yielding clustered data. Generalized estimating equations, alternating logistic regression models, and random-intercept logistic regression models were employed to analyse these correlated binary data. Our results indicated that there are many factors that influence Salmonella risk in broiler flocks, and that they interact. Accounting for interactions between risk factors leads to an improved determination of those risk factors that increase infection with Salmonella. For the conditional analysis, the risk factors found to increase the risk of Salmonella infection on a farm at a current occasion given the previous Salmonella status included: Salmonella infection of day-old chicks (of the current flock); a previously infected flock even though the farm was equipped with a hygiene place to change clothes prior to entering the broiler house; having temporary workmen when there was a separation between birds of different species; and separating birds of different species in the Walloon region relative to the Flanders region. Sanitary measures such as a cleaning and disinfecting procedure conducted by an external cleaning firm, applying the all-in all-out procedure, and hand washing decreased the risk despite their interaction with other factors. From the joint analysis, the most important factors identified for increased risk for persistent Salmonella on a farm involved the interaction between having temporary workmen when there were poultry or farmers in contact with foreign poultry or persons, and the interaction between having temporary workmen when there were poultry or farmers in contact with external poultry or persons.

Suboccipital craniectomy, dorsal laminectomy of C1, durotomy and dural graft placement as a treatment for syringohydromyelia with cerebellar tonsil herniation in Cavalier King Charles spaniels.

OBJECTIVE: To evaluate retrospectively the efficacy of the suboccipital craniectomy and dorsal laminectomy of C1 with durotomy and placement of a dural graft for treatment of syringohydromyelia (SHM) because of cerebellar tonsil herniation in Cavalier King Charles spaniels (CKCS). This technique is used with great success in human medicine. STUDY DESIGN: Four CKCS diagnosed by Magnetic resonance imaging (MRI) of SHM because of cerebellar tonsil herniation and not responsive to medical therapy underwent a suboccipital craniectomy and dorsal laminectomy of C1 (2 dogs) and of C1 and partial C2 (2 dogs) with durotomy and placement of a dural graft. Three dogs were evaluated neurologically 24 hours, 1 month, and 3 months postoperatively and evaluations were compared with preoperative neurological examination. Repeat MRI took place 3 months postoperatively. RESULTS: Neurological examinations showed neither improvement nor progression of clinical signs 3 months postoperatively. MRI showed no regression of syrinx size 3 months postoperatively. CONCLUSION: Improvement was not seen. Given the progressive nature of the disorder, evaluation over a longer period of time is necessary to detect if progression has stopped. Some modification to the surgical technique is needed to accomplish the same results as in human medicine. A study of a larger population is needed to attain more reliable information. CLINICAL RELEVANCE: Suboccipital craniectomy and dorsal laminectomy of C1 with durotomy and placement of a dural graft is a feasible technique in CKCS, but needs some modification to accomplish the same results as in human medicine.