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Evaluation of the pork processing chain as a source of pathogenic and antibiotic-resistant Pseudomonas spp. to humans
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As Pseudomonas spp., têm uma elevada diversidade metabólica, produzem biofilmes e sobrevivem em nichos ecológicos distintos, incluindo humanos, animais, plantas e o ambiente. Pseudomonas aeruginosa é a espécie mais patogénica para humanos, conhecida pela sua resistência antimicrobiana (AMR). Consequentemente, as P. aeruginosa resistentes a carbapenemos foram recentemente classificadas pelo Centro para o Controlo e Prevenção de Doenças (CDC) como uma ameaça séria. Contudo, outras espécies de Pseudomonas também causam infeções em humanos.
O desenvolvimento de AMR foi associado à sobreutilização de antibióticos em veterinária, em profilaxia, tratamento e promoção de crescimento. Porém, as rotas de disseminação de AMR entre o ambiente, a veterinária e a clínica mantêm-se elusivas. O porco é uma das carnes mais consumidas mundialmente e as Pseudomonas spp. são contaminantes desta carne. Contudo, nenhum estudo abordou o papel da cadeia de produção de porco na emergência e disseminação de Pseudomonas resistentes a carbapenemos (CRP).
Este estudo, pretende determinar se a cadeia de produção de carne de porco constitui um risco para a colonização e infeção humanas com CRP. Neste sentido, rastreámos a presença de CRP nas várias fases da cadeia de processamento, confirmámos a identificação das espécies através de métodos moleculares, caracterizámos os padrões de AMR e avaliámos a produção de pigmentos e crescimento a 37°C. Sequenciámos o genoma de isolados representativos, para verificar a semelhança entre as CRP e descrever o seu conteúdo em fatores de resistência e virulência Para detetar a ocorrência de transmissão de CRP ou AMR comparámos os seus genomas e a sequência nucleotídica de genes de AMR selecionados.
Encontrámos uma elevada prevalência (76%) e carga (até 106 CFU/cm2) de Pseudomonas spp. ao longo da cadeia de produção de porco. A carga de Pseudomonas spp. nas superfícies e nas mãos dos operadores de sangria estava acima dos indicadores de referência de higiene. A carga de Pseudomonas spp. nas superfícies do matadouro aumentou após desinfeção e foi superior nas mãos dos consumidores após a manipulação de carne crua, indicando a ineficácia das medidas de higiene utilizadas no matadouro e existência de eventuais procedimentos de risco para colonização humana com CRP. Seis amostras (40%) estavam envolvidas em eventos de transmissão entre as várias fases da cadeia de produção.
Os CRP transportavam carbapenemases (PDC-1, SFH-1) e bombas de efluxo (MexAB-OprM, MexMN-OprM, MexPQ-OpmE, MexXY-OprM), usualmente associados à resistência a carbapenemos, e eram resistentes a outras classes de antibiótico (penicilinas, monobactamos, polimixinas). Encontrámos um elevado número de determinantes de resistência a antibióticos (n=7–23), mas a sua transmissão não se provou. Todos os CRP continham bombas de efluxo, com capacidade de transportar, simultaneamente, vários antibióticos e biocidas.
Cerca de 40% das Pseudomonas spp. cresceu a 37°C e 12% produziram pigmentos e as CRP continham um número elevado (n=83–251) de genes de virulência.
Em conclusão, descobrimos que a cadeia de processamento de porco é um reservatório de Pseudomonas spp. multirresistente (MDR) com um elevado potencial patogénico. Produzimos também evidências que suportam a existência de transmissão de CRP entre as várias fases da cadeia de produção e a sua disseminação para humanos.
Pseudomonas spp., has a high metabolic diversity, produce biofilms, and survive in various ecological sites, including humans, animals, plants, and the environment. Pseudomonas aeruginosa is the most pathogenic species to humans, known for its antimicrobial resistance (AMR). Consequently, carbapenem-resistant P. aeruginosa was recently classified as a serious threat by the Centre for Disease Control and Prevention (CDC). However, other Pseudomonas species also cause infections in humans. AMR development was linked to antibiotic overuse in the veterinary setting, in prophylaxis, treatment and growth promotion. However, the AMR dissemination routes between the environment, the veterinary and the clinical setting are still elusive. Pork is one of the most consumed meats worldwide and Pseudomonas spp. are pork contaminants. However, no study addressed the role of the pork production chain in the emergence and dissemination of carbapenem-resistant Pseudomonas (CRP). This study aimed to determine if the pork production chain constitutes a risk for human colonization and infection with CRP. To achieve this, we screened every step of the pork processing chain for CRP, confirmed species identification by molecular methods, characterized AMR patterns and assessed pigment production and growth at 37ºC. We sequenced the whole genome of representative isolates to compare CRP relatedness and describe their content in resistance and virulence factors. To search for the transmission of CRP or AMR, we compared their genomes and the nucleotide sequence of selected AMR genes. We found a high Pseudomonas spp. prevalence (76%) and load (up to 106 CFU/cm2) throughout the pork production chain. The Pseudomonas spp. load in surfaces and the bleeding operators’ hands was above the hygiene reference indicators. The Pseudomonas spp. load in slaughterhouse surfaces increased after disinfection and was greater in the consumers’ hands after raw meat manipulation, indicating the inefficacy of hygiene measures used in the slaughterhouse and the existence of putative risky procedures for human colonization with CRP. Moreover, six samples (40%) were involved in transmission events between different stages of the production chain. CRP carried carbapenemases (PDC-1, SFH-1) and efflux pumps (MexAB-OprM, MexMN-OprM, MexPQ-OpmE, MexXY-OprM), typically associated with carbapenem-resistance, and were resistant to other antibiotic classes (penicillins, monobactams, polymyxins). We found a high number (n=7–23) of antibiotic resistance determinants, but their transmission was not proven. All CRP carried efflux pumps, capable of transporting, simultaneously, several antibiotics and biocides. Around 40% of Pseudomonas spp. grew at 37°C, 12% produced pigments, and CRP carried a high number (n=83–251) of virulence genes. Overall, we found that the pork processing chain is a reservoir for multidrug-resistant (MDR) Pseudomonas spp. with high pathogenic potential. In addition, we provided evidence supporting the transmission of CRP between different production chain steps and their dissemination to humans.
Pseudomonas spp., has a high metabolic diversity, produce biofilms, and survive in various ecological sites, including humans, animals, plants, and the environment. Pseudomonas aeruginosa is the most pathogenic species to humans, known for its antimicrobial resistance (AMR). Consequently, carbapenem-resistant P. aeruginosa was recently classified as a serious threat by the Centre for Disease Control and Prevention (CDC). However, other Pseudomonas species also cause infections in humans. AMR development was linked to antibiotic overuse in the veterinary setting, in prophylaxis, treatment and growth promotion. However, the AMR dissemination routes between the environment, the veterinary and the clinical setting are still elusive. Pork is one of the most consumed meats worldwide and Pseudomonas spp. are pork contaminants. However, no study addressed the role of the pork production chain in the emergence and dissemination of carbapenem-resistant Pseudomonas (CRP). This study aimed to determine if the pork production chain constitutes a risk for human colonization and infection with CRP. To achieve this, we screened every step of the pork processing chain for CRP, confirmed species identification by molecular methods, characterized AMR patterns and assessed pigment production and growth at 37ºC. We sequenced the whole genome of representative isolates to compare CRP relatedness and describe their content in resistance and virulence factors. To search for the transmission of CRP or AMR, we compared their genomes and the nucleotide sequence of selected AMR genes. We found a high Pseudomonas spp. prevalence (76%) and load (up to 106 CFU/cm2) throughout the pork production chain. The Pseudomonas spp. load in surfaces and the bleeding operators’ hands was above the hygiene reference indicators. The Pseudomonas spp. load in slaughterhouse surfaces increased after disinfection and was greater in the consumers’ hands after raw meat manipulation, indicating the inefficacy of hygiene measures used in the slaughterhouse and the existence of putative risky procedures for human colonization with CRP. Moreover, six samples (40%) were involved in transmission events between different stages of the production chain. CRP carried carbapenemases (PDC-1, SFH-1) and efflux pumps (MexAB-OprM, MexMN-OprM, MexPQ-OpmE, MexXY-OprM), typically associated with carbapenem-resistance, and were resistant to other antibiotic classes (penicillins, monobactams, polymyxins). We found a high number (n=7–23) of antibiotic resistance determinants, but their transmission was not proven. All CRP carried efflux pumps, capable of transporting, simultaneously, several antibiotics and biocides. Around 40% of Pseudomonas spp. grew at 37°C, 12% produced pigments, and CRP carried a high number (n=83–251) of virulence genes. Overall, we found that the pork processing chain is a reservoir for multidrug-resistant (MDR) Pseudomonas spp. with high pathogenic potential. In addition, we provided evidence supporting the transmission of CRP between different production chain steps and their dissemination to humans.
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Ciências biomédicas Biologia molecular Pseudomonas spp. Resistência a carbapenemos Cadeia de produção de carne de porco Origem alimentar AMR