ABSTRACT The extensive use of antimicrobial agents has contributed to the emergence of antimicrobial resistance and multidrug resistance (MDR) in Salmonella, an important zoonotic pathogen that causes outbreaks and sporadic cases of gastroenteritis in humans. The study aimed to investigate the antimicrobial resistance profile of Salmonella strains isolated from poultry in Brazil. A total of 230 Salmonella strains, isolated from cloacal swabs (n=56) and broiler carcasses swabs (n=174) before and after chilling from slaughterhouses under Federal Inspection Service within the period 2012-2017, were analyzed. Serotyping and antibiotic susceptibility testing were performed on all the isolates. Serotyping results showed that 41% of the strains were Salmonella Heidelberg, 29% S. Minnesota, 12% S. Saintpaul, 6.5% S. Enteritidis, 3.9% S. Anatum, 2.2% S. Cerro, 2.2% S. Senftenberg, 1.7% S. Newport, 0.4% S. Ealing, 0.4% S. O:4,5 and 0.4% S. O:9,12. MDR rates of the isolates were 67.4%. S. Heidelberg 89.5%, S. Minnesota 51.5%, S. Saintpaul 82.1%, S. Anatum 66.7%, S. Cerro 60%, S. Senftenberg 40%. Out of the 230 strains, 41.3% presented resistance to Penicillins + beta-lactamase inhibitor, Penicillin, 1st and 2nd Generation Cephalosporin, 3rd and 4th Generation Cephalosporin, Tetracycline and Sulfonamide. Salmonella Heidelberg, S. Saintpaul, S. Anatum, S. Cerro, S. Senftenberg and S. Minnesota were isolated after chilling tank highlighting a food safety concern for the industry of poultry and poultry products indicating a risk to collective health. The high prevalence of MDR nontyphoidal Salmonella obtained in this study limit the options available to treat infectious disease in humans and animals.

ABSTRACT The present study investigated the frequency, level of contamination and serotyping of Salmonella strains isolated from broiler flocks in different processing sites and the fulfillment of a Performance Objective (PO) in frozen chicken breasts, as a risk assessment to measure the efficacy of prevention and control programs applied to reduce the risk of Salmonella spp. in raw poultry meat that contribute to reach food safety and public health goals. From 1,800 samples of cloacal swabs, carcasses before and after immersion chilling and frozen breasts derived from 20 broiler flocks slaughtered at two processing plants located in the mid-west and southern regions of Brazil, 278 samples were positive for Salmonella spp. by polymerase chain reaction (PCR) automated BAX System (DUPONT QUALICOM, USA), and 118 were enumerated by miniaturized most probable number technique. 122 Salmonella spp. strains were serotyped at the National Reference Laboratory of Cholera and Enteric Diseases of Oswaldo Cruz Institute Foundation (FIOCRUZ), showing a dominance of Salmonella Minnesota in every processing steps of the slaughterhouse located in the Brazilian mid-west region. Only 1 lot failed to reach the expected result for the Performance Objective (PO), using a maximum of 10% positivity acceptance for Salmonella spp. in frozen chicken breasts. Qualitative and quantitative results combined may be considered an effective tool to evaluate the effect of prevention and control programs for Salmonella spp. on the safety of the final product.

ABSTRACT The present study investigated the effectiveness of a single Salmonella prevention and control program applied in two different processing plants, located in the states of Mato Grosso do Sul (plant A) and Santa Catarina (Plant B), belonging to the same company, and identified Salmonella strain subtypes isolated from broilers, carcasses before and after chilling, and frozen chicken breasts. The Salmonella prevention and control program was 90% effective in plant A and 100% in plant B, considering a level of 10% positive samples per frozen chicken breast batch acceptable. A total of 128 strains were serotyped, being 10 from drag swabs, 31 from cloacal swabs, 83 from carcasses, and 4 from frozen chicken breasts. After serotyping analysis, 30 strains isolated at different processing steps and drag swabs, and three Salmonella Minnesota strains isolated in 2012 in plant A, were genotyped by PFGE. In plant A, the most frequently strain isolated was Salmonella Minnesota (90.35%), followed by Salmonella Newport (8.77%), and in Plant B, Salmonella Senftenberg (80%). Salmonella Minnesota strains were differentiated by PFGE into 19 pulsotypes distributed in three clusters. The phenotypic identification by serotyping of four strains diverged from their PFGE genotypic results. Most Salmonella Minnesota strains genotyped in plant A and the strains isolated from environmental samples in 2012 in the same broiler processing plant belong to a single cluster, confirming the dominance and persistence of this clone over time.

Fluoroquinolones are antimicrobial agents frequently used in poultry production and in human medicine. The use of such substances must comply with safety criteria, including withdrawal periods, doses, and treatment duration, as their misuse and abuse may cause bacterial resistance and the presence of residues in edible tissues. Consequently, the consumption of animal products with fluoroquinolone residues may result in the transmission of resistant bacteria. In addition, if residues are beyond the acceptable levels, fluoroquinolone active metabolites are harmful to human health. This article presents a review on the use of antimicrobials of the fluoroquinolone class in poultry production, focusing on the development of bacterial resistance to these drugs and the presence of their residues in poultry products.