Frequência de bacilos gram-negativos carreadores de genes de resistência aos antimicrobianos em hortaliças e carnes comercializadas em mercados brasileiros
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Data
2022-04-11
Autores
Bessa Neto, Francisco Ozório [UNIFESP]
Orientadores
Silva, Rodrigo Cayô da [UNIFESP]
Tipo
Dissertação de mestrado
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Introdução: Dentre os principais bacilos gram-negativos multirresistentes (MDR) considerados prioritários pela OMS para vigilância e desenvolvimento de novas opções terapêuticas encontram-se Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae e Escherichia coli resistentes às cefalosporinas de terceira geração e/ou aos carbapenêmicos. Através do conceito de “saúde única”, é possível compreender o papel dos alimentos na disseminação de bactérias resistentes aos antimicrobianos adquiridas durante seu cultivo e criação. Objetivos: Detectar e caracterizar genes de resistência aos antimicrobianos nos principais gêneros bacterianos gram-negativos recuperados de hortaliças e carnes comercializadas em mercados brasileiros. Além disso, determinar o perfil de sensibilidade para as principais classes de antimicrobianos. Métodos: Amostras de alimentos foram incubadas em água peptonada 1%. Posteriormente, alíquotas foram transferidas para microtubos contendo TSB suplementado com antimicrobianos. Após incubação, as amostras que apresentaram turvação foram inoculadas em placas de ágar cromogênico para isolamento de colônias e posterior identificação pela técnica do MALDI-TOF MS. Os isolados de interesse foram submetidos a triagem de sensibilidade à três β-lactâmicos diferentes pelo método de diluição em ágar e, aqueles que apresentaram resistência a um ou mais desses antimicrobianos passaram então por uma triagem dos genes codificadores de β-lactamases pela técnica de PCR. Os isolados positivos para os genes de β-lactamase investigados, tiverem seu perfil de sensibilidade para as demais classes de antimicrobianos determinado. De acordo com o fenótipo encontrado, a presença de genes de resistência a esses antimicrobianos foi também investigada por PCR. Resultados: Um total de 508 bactérias pertencentes aos quatro gêneros de interesse do estudo foram recuperadas das amostras de hortaliças e carnes, dentre as quais, 123 isolados foram resistentes às cefalosporinas de 3ª geração e 26 resistentes ao meropénem. Ao todos, 187 isolados foram positivos ao menos para um dos genes de β-lactamases pesquisados, sendo os mais frequentes blaCTX-M-1/2-like, blaOXA-1-like e blaTEM-like. Altas taxas de resistência às cefalosporinas de amplo espectro foram verificadas entre os isolados de E. coli e K. pneumoniae, o mesmo sendo verificado para sulfametoxazol/trimetoprima e aztreonam entre os isolados de Acinetobacter spp. e Pseudomonas spp., respectivamente. Entre os isolados produtores de β-lactamases, 25 destes apresentaram fenótipo MDR, enquanto nove foram considerados como sendo XDR. Entre os genes de resistência às demais classes de antimicrobianos avaliados, qepA, qnrB, aac(3’)-Ib, qnrS e dfr foram os mais frequentes. Conclusões. O presente estudo relatou a presença de uma diversidade de genes de resistência aos antimicrobianos em isolados bacterianos gram-negativos proveniente de amostras de hortaliças e carnes adquiridas em mercados brasileiros, incluindo Acinetobacter spp. e Pseudomonas spp.. Isso evidencia a necessidade de um programa de vigilância de resistência aos antimicrobianos que englobe também os alimentos como fonte de genes de resistência aos antimicrobianos e, negligenciá-los ainda mais, seria um erro grave se quisermos realmente combater o fenômeno da resistência bacteriana.
Introduction. Among the main multidrug-resistant (MDR) gram-negative bacilli considered a priority by WHO for surveillance and development of new therapeutic options are Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli resistant to third-generation cephalosporins and/or carbapenems. Through the concept of “one health”, it is possible to understand the role of food in the spread of bacteria acquired during its cultivation and the raising. Goals. To detect and characterize antimicrobial resistance genes in the main BGNs recovered from vegetables and meat sold in Brazilian markets. Furthermore, to determine the antimicrobial susceptibility profile for the main antimicrobial classes. Methods. Food samples were incubated in 1% peptone water; then, aliquots were transferred to microtubes containing TSB supplemented with drugs, and those samples that became cloudy after incubation were inoculated onto chromogenic agar plates for bacterial colony isolation and subsequent identification by MALDI-TOF MS technique. The isolates of interest were screened for susceptibility to three β-lactams by agar dilution. Molecular detection of β-lactamase encoding genes were performed type by PCR for those isolates presented resistant to the β-lactams ceftazidime, ceftriaxone, and meropenem. All isolates carrying β-lactamase encoding genes were subjected to a susceptibility test for the other antimicrobial classes and, subsequently, according to the resistance phenotype, acquired antimicrobial resistance genes to fluoroquinolones, aminoglycosides, polymyxins, sulfonamides, and diaminopyrimidines were also screened. Results. A total of 508 bacterial isolates belonging to the four genera of interest were recovered from vegetables and meats, among which, 123 were resistant to 3rd-generation cephalosporins and 26 were resistant to meropenem. β-lactamase encoding genes were found in 187 isolates, of which the most abundant were blaCTX-M-1/2-like, blaOXA-1-like, and blaTEM-like. High rates of resistance to broad-spectrum cephalosporins were observed among E. coli and K. pneumoniae isolates, while high resistance rates to sulfamethoxazole/trimethoprim and aztreonam were observed among Acinetobacter spp. and Pseudomonas spp. isolates, respectively. Among the β-lactamase-producing Gram-negative isolates, 25 and nine of them had an MDR and a XDR profiles, respectively. The most common antimicrobial resistance genes to other classes evaluated were qepA, qnrB, aac(3')-Ib, qnrS, and dfr. Conclusions. The present study reported a diversity of antimicrobial resistance genes among Gram-negative isolates recovered from meat and vegetables sold in Brazilian markets, including Acinetobacter spp. and Pseudomonas spp. This highlights the need for an antimicrobial resistance surveillance program that also encompasses food as a reservoir for antimicrobial resistance genes and neglecting them would be a serious mistake if we really want to combat antimicrobial resistance phenomenon.
Introduction. Among the main multidrug-resistant (MDR) gram-negative bacilli considered a priority by WHO for surveillance and development of new therapeutic options are Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli resistant to third-generation cephalosporins and/or carbapenems. Through the concept of “one health”, it is possible to understand the role of food in the spread of bacteria acquired during its cultivation and the raising. Goals. To detect and characterize antimicrobial resistance genes in the main BGNs recovered from vegetables and meat sold in Brazilian markets. Furthermore, to determine the antimicrobial susceptibility profile for the main antimicrobial classes. Methods. Food samples were incubated in 1% peptone water; then, aliquots were transferred to microtubes containing TSB supplemented with drugs, and those samples that became cloudy after incubation were inoculated onto chromogenic agar plates for bacterial colony isolation and subsequent identification by MALDI-TOF MS technique. The isolates of interest were screened for susceptibility to three β-lactams by agar dilution. Molecular detection of β-lactamase encoding genes were performed type by PCR for those isolates presented resistant to the β-lactams ceftazidime, ceftriaxone, and meropenem. All isolates carrying β-lactamase encoding genes were subjected to a susceptibility test for the other antimicrobial classes and, subsequently, according to the resistance phenotype, acquired antimicrobial resistance genes to fluoroquinolones, aminoglycosides, polymyxins, sulfonamides, and diaminopyrimidines were also screened. Results. A total of 508 bacterial isolates belonging to the four genera of interest were recovered from vegetables and meats, among which, 123 were resistant to 3rd-generation cephalosporins and 26 were resistant to meropenem. β-lactamase encoding genes were found in 187 isolates, of which the most abundant were blaCTX-M-1/2-like, blaOXA-1-like, and blaTEM-like. High rates of resistance to broad-spectrum cephalosporins were observed among E. coli and K. pneumoniae isolates, while high resistance rates to sulfamethoxazole/trimethoprim and aztreonam were observed among Acinetobacter spp. and Pseudomonas spp. isolates, respectively. Among the β-lactamase-producing Gram-negative isolates, 25 and nine of them had an MDR and a XDR profiles, respectively. The most common antimicrobial resistance genes to other classes evaluated were qepA, qnrB, aac(3')-Ib, qnrS, and dfr. Conclusions. The present study reported a diversity of antimicrobial resistance genes among Gram-negative isolates recovered from meat and vegetables sold in Brazilian markets, including Acinetobacter spp. and Pseudomonas spp. This highlights the need for an antimicrobial resistance surveillance program that also encompasses food as a reservoir for antimicrobial resistance genes and neglecting them would be a serious mistake if we really want to combat antimicrobial resistance phenomenon.
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Citação
BESSA-NETO, Francisco Ozório. Frequência de bacilos gram-negativos carreadores de genes de resistência aos antimicrobianos em hortaliças e carnes comercializadas em mercados brasileiros. 2022. 152 f. Dissertação (Mestrado em Infectologia) – Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP). São Paulo, 2022.