Phage cocktail SalmoFREE® reduces Salmonella on a commercial broiler farm.

According to the World Health Organization, Salmonella is one of the most important zoonotic foodborne pathogens. Poultry products are thought to be the main source of Salmonella, which means that it is necessary to control Salmonella at the pre-harvest stage. Bacteriophages, acting as host-specific parasites of bacterial cells, represent one of the alternatives to antibiotics that can contribute to food safety and security. The present study evaluated the effectiveness of the bacteriophage cocktail SalmoFREE® to control Salmonella on a commercial broiler farm. We assessed the relationship between the use of SalmoFREE® and productivity parameters (feed conversion, weight gain, homogeneity). Two field trials (trial 1 n = 34,986; trial 2 n = 34,680) were carried out under commercial rearing conditions on a Colombian broiler farm with a record of Salmonella presence. Each trial comprised 2 control chicken houses and 2 experimental ones. SalmoFREE® and a control suspension were delivered in the drinking water at 3 time points in the production cycle, and the presence of Salmonella was assessed in cloacal swabs the day before and after the treatments. Results revealed that SalmoFREE® controls the incidence of Salmonella and does not affect the animals nor the production parameters, demonstrating its efficacy and innocuity at the production scale. We detected phage-specific genes in samples of total DNA extracted from ceca after the treatment with SalmoFREE®, and tested for the appearance of cocktail-resistant Salmonella, which showed to be an uncommon event. These results contribute relevant information to the adoption of phage therapy as an alternative to growth-promoter antibiotics on poultry farms.

Detection of linezolid resistance due to the optrA gene in Enterococcus faecalis from poultry meat from the American continent (Colombia).

Background: Three Enterococcus isolates obtained from retail chicken collected in 2010-11 as part of the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS) showed reduced susceptibility towards linezolid (MIC 8 mg/L). Objectives: This study aimed at characterizing the isolates resistant to linezolid and detecting the resistance mechanism. Methods: Strains were analysed in 2011-12 without successful detection of the resistance mechanism. All isolates were found negative for the cfr gene and no 23S rRNA mutations were detected. In 2016, with the novel resistance gene optrA being described, the WGS data were re-analysed using in silico genomic tools for confirmation of species, detection of virulence and resistance genes, MLST and SNP analyses and comparison of the genetic environment with the previously published plasmid pE349. Results: : Three Enterococcus faecalis isolates were found positive for the optrA gene encoding resistance to linezolid and phenicols. Additional screening of 37 enterococci strains from the same study did not detect any further positives. Typing showed that two of the isolates belong to ST59, while the last belongs to ST489. All isolates carry genes encoding resistance to macrolide-lincosamide-streptogramin B, tetracycline and phenicols. In addition, the ST489 isolate also carries genes conferring aminoglycoside resistance and is resistant to quinolones, but no plasmid-mediated gene was detected. The optrA gene regions of the three plasmids showed high similarity to the originally reported optrA -carrying plasmid pE349. Conclusions: To the best of our knowledge, this is the first description of the optrA gene in E. faecalis isolated from poultry meat in the Americas.

The Establishment of the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS): A Pilot Project on Poultry Farms, Slaughterhouses and Retail Market.

The development of antimicrobial resistance among bacteria (AMR) is currently one of the world's most pressing public health problems. The use of antimicrobial agents in humans and animals has resulted in AMR which has narrowed the potential use of antibiotics for the treatment of infections in humans. To monitor AMR and to develop control measures, some countries, such as the USA, Canada and Denmark, have established national integrated surveillance systems (FDA, , CIPARS, 2007, DANMAP,2002). The components of these programs monitor changes in susceptibility/resistance to antimicrobial agents of selected zoonotic pathogens and commensal organisms recovered from animals, retail meats and humans. The rapid development of Colombia's animal production industry has raised food safety issues including the emergence of antibiotic resistance. The Colombian Integrated Surveillance Program for Antimicrobial Resistance (COIPARS) was established as a pilot project to monitor AMR on poultry farms, slaughter houses and retail markets.

Prevalence, risk factors, and antimicrobial resistance profiles of Salmonella from commercial broiler farms in two important poultry-producing regions of Colombia.

Salmonella is one of the most common foodborne pathogens associated with diarrheal disease in humans. Food animals, especially poultry, are important direct and indirect sources of human salmonellosis, and antimicrobial resistance is an emerging problem of public health concern. The use of antimicrobials benefits producers but contributes to the emergence of antimicrobial resistant bacteria. As a step toward implementing the Colombian Integrated Program for Antimicrobial Resistance Surveillance, this study was conducted to establish the prevalence, distribution of serovars, antimicrobial resistance profiles, and risk factors for Salmonella on poultry farms in the two largest states of poultry production in Colombia. Salmonella was isolated from 41% of farms and 65% of the 315 chicken houses sampled. Salmonella Paratyphi B variant Java was the most prevalent serovar (76%), followed by Salmonella Heidelberg (23%). All Salmonella isolates were resistant to 2 to 15 of the antimicrobial drugs tested in this study. For Salmonella Paratyphi B variant Java, 34 drug resistance patterns were present. The predominant resistance pattern was ciprofloxacin, nitrofurantoin, tetracycline, trimethoprim-sulfamethoxazole, ceftiofur, streptomycin, enrofloxacin, and nalidixic acid; this pattern was detected in 15% of isolates. The resistance pattern of tetracycline, ceftiofur, and nalidixic acid was found in over 40% of the isolates of Salmonella Heidelberg. Of the biosecurity practices considered, two factors were significantly associated with reduction in Salmonella: cleaning of fixed equipment and composting of dead birds on the farm. Findings from the present study provide scientific evidence to inform implementation of official policies that support new biosecurity legislation in an effort to decrease the prevalence of Salmonella on Colombian poultry farms.