Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016)

ABSTRACT: Salmonella is a major cause of foodborne illness worldwide, and poultry and its derived products are the most common food products associated with salmonellosis outbreaks. Some countries, including Brazil, have experienced an increased prevalence of Salmonella Heidelberg among their poultry flocks. Some isolates have also presented high resistance to antimicrobial agents and persist in the poultry farm environment. This study aimed to compare the susceptibility of S. Heidelberg strains isolated in 2006 with those isolated in 2016 against disinfectants and antimicrobial agents. The results showed that all the strains were highly susceptible to sodium hypochlorite, regardless of the conditions and year of isolation. Resistance to benzalkonium chloride varied according to the conditions applied, but not to the year of isolation. Increased antimicrobial resistance from 2006-2016 was observed only for tetracycline. The results suggest that the antimicrobial and disinfectant resistance of S. Heidelberg did not increase for ten years (2006-2016). However, further analysis should include a larger number of S. Heidelberg isolates from poultry origin and additional antimicrobial agents for more precise conclusions about the increasing in antimicrobial resistance in the last years.

RESUMO: Salmonella é uma das principais causas das doenças transmitidas por alimento em todo o mundo, e a carne de frango e produtos derivados são os principais alimentos associados com surtos de salmonelose em humanos. Alguns países, incluindo o Brasil, têm observado um aumento da ocorrência de Salmonella Heidelberg nas suas granjas avícolas. Além disto, alguns isolados têm apresentado alta resistência aos antimicrobianos e têm persistido no ambiente de produção avícola. Neste contexto, o objetivo deste estudo foi comparar a susceptibilidade de cepas de S. Heidelberg isoladas em 2006 com aquelas isoladas em 2016 contra desinfetantes e agentes antimicrobianos. Os resultados demonstraram que as cepas foram altamente resistentes a hipoclorito de sódio, independentemente das condições e do ano de isolamento. A resistência ao cloreto de benzalcônio variou de acordo com as condições testadas, mas não com o ano de isolamento. Um aumento da resistência aos antimicrobianos de 2006 a 2016 foi observado apenas para tetraciclina. Os resultados sugerem que a resistência aos desinfetantes e aos antimicrobianos não aumentou em um período de dez anos (2006-2016). Entretanto, novas análises devem incluir um número maior de cepas de S. Heidelberg isoladas de fontes avícolas e outros agentes antimicrobianos para uma conclusão mais precisa sobre o aumento da resistência antimicrobiana nos últimos anos.

Antimicrobial and disinfectant resistance of Salmonella Heidelberg from Brazilian flocks did not increase for ten years (2006-2016) / A resistência a desinfetantes e a antimicrobianos não aumentou em um período de 10 anos (2006 a 2016) em Salmonella Heidelberg isoladas de granjas avícolas brasileiras

Salmonella is a major cause of foodborne illness worldwide, and poultry and its derived products are the most common food products associated with salmonellosis outbreaks. Some countries, including Brazil, have experienced an increased prevalence of Salmonella Heidelberg among their poultry flocks. Some isolates have also presented high resistance to antimicrobial agents and persist in the poultry farm environment. This study aimed to compare the susceptibility of S. Heidelberg strains isolated in 2006 with those isolated in 2016 against disinfectants and antimicrobial agents. The results showed that all the strains were highly susceptible to sodium hypochlorite, regardless of the conditions and year of isolation. Resistance to benzalkonium chloride varied according to the conditions applied, but not to the year of isolation. Increased antimicrobial resistance from 2006-2016 was observed only for tetracycline. The results suggest that the antimicrobial and disinfectant resistance of S. Heidelberg did not increase for ten years (2006-2016). However, further analysis should include a larger number of S. Heidelberg isolates from poultry origin and additional antimicrobial agents for more precise conclusions about the increasing in antimicrobial resistance in the last years.(AU)

Salmonella é uma das principais causas das doenças transmitidas por alimento em todo o mundo, e a carne de frango e produtos derivados são os principais alimentos associados com surtos de salmonelose em humanos. Alguns países, incluindo o Brasil, têm observado um aumento da ocorrência de Salmonella Heidelberg nas suas granjas avícolas. Além disto, alguns isolados têm apresentado alta resistência aos antimicrobianos e têm persistido no ambiente de produção avícola. Neste contexto, o objetivo deste estudo foi comparar a susceptibilidade de cepas de S. Heidelberg isoladas em 2006 com aquelas isoladas em 2016 contra desinfetantes e agentes antimicrobianos. Os resultados demonstraram que as cepas foram altamente resistentes a hipoclorito de sódio, independentemente das condições e do ano de isolamento. A resistência ao cloreto de benzalcônio variou de acordo com as condições testadas, mas não com o ano de isolamento. Um aumento da resistência aos antimicrobianos de 2006 a 2016 foi observado apenas para tetraciclina. Os resultados sugerem que a resistência aos desinfetantes e aos antimicrobianos não aumentou em um período de dez anos (2006-2016). Entretanto, novas análises devem incluir um número maior de cepas de S. Heidelberg isoladas de fontes avícolas e outros agentes antimicrobianos para uma conclusão mais precisa sobre o aumento da resistência antimicrobiana nos últimos anos.(AU)

Characteristics of etiology and drug and disinfectant resistant genes of Yersinia pestis in natural plague foci of Haixi Prefecture, Qinghai Province / 中华地方病学杂志

Objective To analyze the biological characteristics of Yersinia pestis strains in Haixi Prefecture,Qinghai Province,in order to provide a scientific basis for plague prevention and control in future.Methods Totally 181 strains were separated from variety kinds of host in Haixi Prefecture,Qinghai Province from 1957 to 2011,and these strains were conducted biochemical test,virulence factor evaluation,plasmid analysis,different region (DFR) genotyping,drug and disinfectant resistant genes detection;79 of the 181 strains were examined by toxicity test and classified according to the criteria (minimum lethal dose:MLD≤ 10 000 was velogenic strain,10 000 ＜ MLD ＜ 100 000 was moderate virulence strain,MLD ≥ 100 000 was hypovirulent strain).Results According to six biochemical typing about gelatin candy,rhamnose,maltose,melibiose,glycerin and denitrification,the 181 strains of Yersinia pestis were antique biovar and Qing-Tibet Plateau ecotype.Aproportion of 81.22％ (147/181) of Yersiniapestis strains contained all the four virulence factors (F1,Pst Ⅰ,VW,Pgm).Totally 63.54％ (115/181) of the strains contained 3 kinds of plasmid-6 × 106,45 × 106,and 52 × 106;31.49％ (57/181) of the strains contained 3 kinds of plasmid-6 × 106,45 × 106,and 65 × 106.The strains had 8 genomovars,and were given priority to genomovar 8 (109 strains),secondly,genomovar 32 (33 strains),genomovar 5 (20 strains),genomovar 1b(i4 strains),genomovar 44 (2 strains),genomovar 7 (1 strain),genomovar 37 (1 strain),and genomovar 49 (1 strain).Among the 181 Yersinia pestis strains,strains with genes related to streptomycin resistance,sulfanilamide resistance,beta lactam resistance and disinfectant resistance were not found;and 75 of 79 strains were velogenic strains by toxicity test (MLD ≤ 10 000),accounted for 94.94％ (75/79).Conclusion The strains separated in Haixi Prefecture,Qinghai Province have the characteristics of Qinghai-Tibet Plateau plague's pathogen and have strong toxicity;all strains don't have the characteristics of drug and disinfectant resistance genes.

Carriage of disinfectant resistance genes in clinically isolated Escherichia coli and minimal inhibitory concentration of five disinfectants / 中国感染控制杂志

Objective To understand the disinfectant resistance of clinically isolated Escherichia coli (E.coli)and carriage of disinfectant resistance genes.Methods Disinfectant resistance gene sugE (c ),sugE (p ),qacEΔ1 ,and qacE of 82 isolates of E.coli were detected with polymerase chain reaction (PCR),minimal inhibitory concentra-tions (MICs)were measured with agar dilution methods.Results Among 82 E.coli isolates,positive rates of dis-infectant resistance gene sugE (c ),sugE (p ),qacEΔ1 ,qacE,sugE (c )+qacEΔ1 ,and qacE+qacEΔ1 +sugE (c ) were 84.15% (n=69),1 .22% (n=1),76.83% (n=63),73.17 % (n=60),68.29% (n=56),and 59.76% (n=49)respectively.There was no significant differences in carriage status of four disinfectant resistance genes be-tween extended-spectrumβ-lactamases (ESBLs)-producing and non-ESBLs-producing strains,as well as cefepime sensitive and resistant strains (all P >0.05);MIC values of benzalkonium chloride,cetylpyridinium chloride,am-monium bromide,and triclosan for 82 isolates of E.coli were all > standard stain;MIC values of chlorhexidine for 32 isolates of E.coli were all > standard stain,for 50 other E.coli strains were all ≤ standard strain.There were no significant difference in MIC values of benzalkonium chloride,cetylpyridinium chloride,ammonium bromide,and triclosan between ESBLs-and non-ESBLs-producing strains,as well as cefepime sensitive and resistant strains(all P >0.05);while MIC values of chlorhexidine showed a significant difference (both P <0.05).Conclusion Detection rates of disinfectant resistance gene qacE,qacEΔ1 ,and sugE(c)in E.coli from clinical specimens are high,MICs of disinfectants such as benzalkonium chloride for E.coli are generally higher than standard strain.

Bacterial Disinfectant Resistance / 微生物学通报

Bacterial disinfectant resistance is the phenomenon that minimal inhibitory concentration or minimal bactericidal concentration of a certain disinfectant increases after a certain bacterium contacts with it many times. It exists widespread. Many species of bacteria are may resistant to a certain disinfectant, and a species of bacterium is may resistant to many disinfectant Disinfectant selectivity pressure is the extrinsic agent of bacterial disinfectant resistance. Resistance mechanisms include bacterial biochemistry structure, genetics pathway and enzymology pathway. There is relationship in disinfectant resistance and drug resistance. We should strengthen study and monitoring, enact unified standard and application specification to reduce bacterial disinfectant resistance.