Intrinsic and Extrinsic Aspects on Campylobacter jejuni Biofilms

Abstract

Biofilm represents a way of life that allows greater survival of microorganisms in hostile habitats. Campylobacter jejuni is able to form biofilms in vitro and on surfaces at several points in the poultry production chain. Genetic determinants related to their formation are expressed differently between strains and external conditions are decisive in this respect. Our approach combines phylogenetic analysis and the presence of seven specific genes linked to biofilm formation in association with traditional microbiology techniques, using Mueller Hinton and chicken juice as substrates in order to quantify, classify, determine the composition and morphology of the biomass of simple and mixed biofilms of 30 C. jejuni strains. It also evaluates the inhibition of its formation by biocides commonly used in industry and also by zinc oxide nanoparticles. Genetic analysis showed high heterogeneity with the identification of 23 pulsotypes. Despite the diversity, the presence of flaA, cadF, luxS, dnaJ, htrA, cbrA, and sodB genes in all strains shows the high potential for biofilm formation. This ability was only expressed in chicken juice, where they presented phenotype of a strong biofilm producer, with a mean count of 7.37 log CFU/mL and an ultrastructure characteristic of mature biofilm. The composition of simple and mixed biofilms was predominantly composed by proteins. The exceptions were found in mixed biofilms with Pseudomonas aeruginosa, which includes a carbohydrate-rich matrix, lower ability to sessile form in chicken juice and compact architecture of the biofilm, this aspects are intrinsic to this species. Hypochlorite, chlorhexidine, and peracetic acid were more effective in controlling viable cells of C. jejuni in biofilm, but the existence of tolerant strains indicates exposure to sublethal concentrations and development of adaptation mechanisms. This study shows that in chicken juice C. jejuni presents greater potential in producing mature biofilms.

Consumption of minas frescal cheese may be a source of human infection by Campylobacter jejuni

“…The dnaJ gene is associated with thermotolerance and stress response (MELO et al, 2017), and presents relevant when it comes to variations in temperature (STINTZI;WHITWORTH, 2003). The transcription pattern for this gene was numerically similar to that found for ciaB in both strains.…”

BIOFILMES DE Campylobacter spp

“…A bactéria transita entre vida livre e forma séssil, ligada a superfície biótica ou abiótica, cercada por matriz viscosa (MELO et al, 2017). A camada de exopolissacarídeo (EPS) protege a população bacteriana das condições ambientais, além do que, as bactérias apresentam taxas mais lentas de crescimento e metabolismo (REUTER et al, 2010;BORGES et al, 2016).…”

“…A formação de biofilme pode ser mais eficiente com a presença do "chicken juice" (suco de frango), podendo levar a biofilmes fortemente aderentes, gerando uma forma de persistência em abatedouros (REUTER et al, 2010;BROWN et al, 2015;MELO et al, 2017). As partículas nutritivas no "chiken juice" podem formar uma fina camada acima das superfícies abióticas que facilitam essa adesão bacteriana (LI et al, 2017).…”

“…Em trabalho de Melo e colaboradores (2017), o uso de clorexidina 1%, hipoclorito de sódio 1% e ácido peracético 0,8% apresentaram maior eficiência no controle de biofilmes de C. jejuni quando comparados a nanopartículas de ZnO. Por outro lado, tolerância aos desinfetantes, verificada em trabalhos, sugere que o uso de maneira inadequada destes na indústria, como a exposição a subdoses, leva a adaptação dessas bactérias (TECHARUVICHIT et al, 2016;MELO et al, 2017).…”

“…Segundo os autores, estes compostos podem melhorar a penetração de agentes antimicrobianos na matriz, abrindo porta para desenvolvimento de proteolíticos semelhantes para uso industrial, associados a desinfetantes. Assim, sugere-se a associação de planos de higiene a agentes diferentes, respeitando período entre limpezas, além do uso de estratégias, como a rotação periódica dos biocidas (MELO et al, 2017).…”