Pesquisa de Campylobacter spp., genes de virulência, resposta à ação de enterocinas e antimicrobiana in vitro, em carcaças e frangos de corte

Abstract

Campylobacter spp. it is considered an important gastrointestinal bacterial pathogen due to its implications for industrial poultry farming and public health. The objective was to research Campylobacter spp. in carcasses and cloacal swabs of broiler chickens, detect the species C. jejuni, C. coli and C. lari of importance for public health, the genes related to virulence, evaluate the action of enterocins and determine the antimicrobial resistance profile. Skin samples from different regions of the carcass (chilled and frozen), liver and gizzard and cloacal swabs of broiler chickens were evaluated. The isolates were subjected to Polymerase Chain Reaction (PCR) to identify the genus and species, virulence and resistance genes. The minimum inhibitory concentration (MIC) was used to determine the antimicrobial activity of enterocins. Assessment of susceptibility to antibiotics was performed using the disk diffusion method. All isolates were subjected to PCR and isolates from broiler cloacal swabs were subjected to Matrix-Assisted Laser Desorption Ionization Time-of-Light (MALDI-TOF MS). An investigative questionnaire was applied to veterinarians and zootechnicians on the topic. In carcass samples, 376 isolates of Campylobacter spp. and 26 (7%) C. jejuni were obtained, C. coli and C. lari were not detected. The highest frequency of C. jejuni was in chilled carcasses (88.5%) (p < 0.0001) and in frozen carcasses (11.5%). The most frequent location of C. jejuni was the skin of the chest (27.0%), followed by the skin of the wing (23.0%), skin of the cloaca (19.0%) and skin of the neck (8.0%), gizzard (15.0%) and liver (8.0%). The gene frequency was cdtA (11.5%), cdtB (11.5%), cdtC (19.0%), sodB (34.5%), dnaJ (11.5%), cmeA (15.0%), cmeB (15.0%) and cmeC (15.0%). In broiler chickens, positive samples were found for C. jejuni (90.0%) and C. lari (30.0%), but C. coli was not detected. The gene frequency of samples positive for C. jejuni revealed that the genes cdtB, dnaJ, cmeA, cmeB and cmeC were detected in all samples, followed by the genes cdtA (92.6%), cdtC (66.6%) and sodB (51.8%). In all samples positive for C. lari, the genes cdtB, dnaJ, sodB, cmeB and cmeC were detected, followed by the genes cdtA (85.7%), cmeA (85.7%) and cdtC (28.5%). The isolates from cloacal swabs, negative in PCR for Campylobacter spp., were identified by MALDI-TOF MS, being Proteus mirabilis (79.0%) and Providencia stuartii (21.0%). The antimicrobial activity of enterocins inhibited the growth of (98.5%) C. jejuni. Multidrug resistance was found in C. jejuni (100.0%) from carcasses. This study revealed that participants (80.7%) said they had little knowledge about Campylobacter. In view of the above, it is concluded that chicken carcasses contaminated by multidrug-resistant C. jejuni represent a risk to Public Health. Thus, infected broiler chickens can be considered a source of infection for Campylobacter spp. in the poultry chain. Further investigations should be carried out to explore the use of enterocins in controlling this pathogen, as the results are promising.