Characterization of quinolone resistance in Salmonella spp. isolates from food products and human samples in Brazil

Abstract Non-typhoidal salmonellosis is an important zoonotic disease caused by Salmonella enterica. The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance in Salmonella spp. and its association with fluoroquinolone susceptibility in Brazil. A total of 129 NTS isolates (samples from human origin, food from animal origin, environmental, and animal) grouped as from animal (n = 62) and human (n = 67) food were evaluated between 2009 and 2013. These isolates were investigated through serotyping, antimicrobial susceptibility testing, and the presence of plasmid-mediated quinolone resistance (PMQR) genes (qnr, aac(6')-Ib) and associated integron genes (integrase, and conserved integron region). Resistance to quinolones and/or fluoroquinolones, from first to third generations, was observed. Fifteen isolates were positive for the presence of qnr genes (8 qnrS, 6 qnrB, and 1 qnrD) and twenty three of aac(6')-Ib. The conserved integron region was detected in 67 isolates as variable regions, from ±600 to >1000 pb. The spread of NTS involving PMQR carriers is of serious concern and should be carefully monitored.

Salmonella Hadar phage types isolated from different sources of foodchain in Brazil

The gastroenteritis incidence caused by Salmonella Hadar has increased over the last decades worldwide. The uncontrolled use of antimicrobials for treating human patients and veterinary field contributes to increase the multidrug resistance of this serovar. In the present investigation, a total of 179 S. Hadar isolates from different sources of foodchain in Brazil were phage typed and analyzed for their antimicrobial resistance profile. The main S. Hadar phage types isolated were PT 38, PT 39, PT 40, PT 11, PT 34, PT 1 and PT 22. Others phage types as PT 13, PT 19, PT 21, PT 23, PT 31, PT 33 and PT 37 were obtained in low percentages. A total of 35,7 percent S. Hadar strains were resistant to two or more antimicrobials drugs. Furthermore, no resistance to third generation cephalosporin or ciprofloxacin was identified in these strains. Those results appoint to S. Hadar phage types circulating among animals, food and humans, as well as the increasing of multidrug resistance. The surveillance and monitoring of S. Hadar strains based on phage typing and antimicrobial resistance profile are useful for detecting outbreaks, identifying sources of infection and implementing prevention and control measures of salmonellosis.

A incidência de gastrenterite causada por Salmonella Hadar tem aumentado ao longo dos anos em todo o mundo. O uso indiscriminado de antimicrobianos na clínica humana e veterinária tem contribuído para o aumento da multiresistência deste sorovar. No presente estudo, 179 cepas de S. Hadar isoladas de diferentes fontes da cadeia alimentar no Brasil foram fagotipadas e analisadas quanto ao perfil de resistência antimicrobiana. Os principais fagotipos de S. Hadar isolados foram PT 38, PT 39, PT 40, PT 11, PT 34, PT 1 e PT 22. Outros fagotipos como PT 13, PT 19, PT 21, PT 23, PT 31, PT 33 e PT 37 foram obtidos em menores percentagens. Um total de 35,7 por cento das cepas avaliadas foi resistente a dois ou mais antimicrobianos. Por outro lado, não foi observada resistência a cefalosporinas de terceira geração ou ciprofloxacina. Esses resultados apontam para a circulação de fagotipos de S. Hadar entre animais, alimentos e seres humanos, bem como o aumento da multiresistência antimicrobiana. O monitoramento de cepas de S. Hadar baseado na fagotipagem e no padrão de resistência aos antimicrobianos são ferramentas úteis na detecção de surtos, identificação das fontes de infecção, além de auxiliar na implantação de programas de controle e prevenção de salmoneloses.

Phage typing and Multidrug resistance profile in S. Typhimurium isolated from different sources in Brazil from 1999 to 2004

Salmonella Typhimurium has become a widespread cause of salmonellosis among humans and animals worldwide. In Brazil, Salmonella Typhimurium (STM) is one of the most prevalent serovars isolated from food for human consumption. The uncontrolled sale and use of antimicrobials in agriculture and for treating human patients contributes to increase multidrug resistance of this serovar. In the present study, a total of 278 STM isolates from different sources and regions of Brazil over the period 1999 to 2004 were phage typed and analyzed for their antimicrobial resistance profile at Laboratory of Enterobacteria, Oswaldo Cruz Institute, FIOCRUZ. The main STM phage types isolated were DT 193 (64.3 percent), DT 19 (17.4 percent) and DT 18 (4 percent). Others phage types as DT 10 (2 percent), DT 27 (3.24 percent), DT 13 (0.36 percent), DT 22 (0.36 percent), DT 28 (0.36 percent), DT 29 (0.36 percent) and DT 149 (0.36 percent) were obtained in low percentages. A total of 54 percent STM strains were resistant to three or more antimicrobial classes, while no resistance to third generation cephalosporin or ciprofloxacin was identified in these strains. Those results show the STM phage types circulating among animals, food for human consumption and humans in Brazil as well as the increasing of multidrug resistance. The surveillance of STM strains based on phage typing and antimicrobial resistance profile are useful for detecting outbreaks, identifying sources of infection and implementing prevention and control measures.

Salmonella Typhimurium é considerada uma das principais bactérias causadoras de salmonelose nos animais e no homem em todo o mundo. No Brasil, Salmonella Typhimurium é um dos mais prevalentes sorovares isolados de alimentos para consumo humano. O uso indiscriminado de antibióticos em produtos agrícolas e no tratamento de pacientes humanos tem contribuído para aumentar a multirresistência desse sorovar a diversos antimicrobianos. No presente estudo, 278 cepas de STM foram selecionadas de diferentes fontes e regiões do Brasil, no período de 1999 a 2004 e realizadas a fagotipagem e análise do perfil de resistência antimicrobiana no Laboratório de Enterobactérias, Instituto Oswaldo Cruz, FIOCRUZ. Os principais fagotipos isolados foram DT 193 (64,3 por cento), DT 19 (17,4 por cento) e DT 18 (4 por cento). Os fagotipos DT 10 (2 por cento), DT 27 (3,24 por cento), DT 13 (0,36 por cento), DT 22 (0,36 por cento), DT 28 (0,36 por cento), DT 29 (0,36 por cento) e DT 149 (0,36 por cento) foram isolados em menores percentuais. Um total de 54 por cento das cepas de STM foi resistente a três ou mais classes de antimicrobianos e não foi observada resistência a cefalosporinas de terceira geração ou ciprofloxacina. Esses resultados indicam os principais lisotipos de Salmonella Typhimurium circulantes entre os animais, alimentos de consumo humano e seres humanos no Brasil, bem como o aumento da multirresistência antimicrobiana. O monitoramento de cepas de Salmonella Typhimurium baseado na fagotipagem e no padrão de resistência antimicrobiana são ferramentas úteis para detectar surtos, identificar a fonte de infecção e implementar programas de prevenção e controle de salmonelose.