O objetivo deste estudo foi avaliar a formação de biofilme e o perfil de susceptibilidade a antimicrobianos de Pseudomonas aeruginosa isoladas na avaliação da qualidade microbiológica de 80 amostras de águas minerais naturais comercializadas em garrafões de 20 L. Foi realizada a quantificação de P. aeruginosa e enterococos; a pesquisa de coliformes totais, coliformes termotolerantes e de clostrídios sulfito redutores (CSR). A produção de biofilme de P. aeruginosa foi avaliada em caldo infusão cérebro-coração (BHI) e em água mineral natural estéril nas temperaturas de 25 e 35ºC por 24 e 48 h. A avaliação da susceptibilidade a antimicrobianos foi realizada pelo teste de difusão em ágar (Kirby-Bauer). De 80 amostras analisadas, 40 (50%) apresentaram qualidade microbiológica insatisfatória segundo a RDC nº275/05. Trinta e oito (47,5%) amostras apresentaram P. aeruginosa, nove (11,2%) coliformes totais, quatro (5,0%) CSR e uma (1,2%) coliformes termotolerantes. Nenhuma amostra apresentou contaminação por enterococos. Dezesseis cepas (51,6%) de P. aeruginosa foram classificadas como não aderentes ou fracamente aderentes, tanto no BHI quanto na água mineral. Contudo, cinco cepas (16,1%) apresentaram-se fortemente aderentes nas duas matrizes, principalmente no caldo BHI e na temperatura de 25ºC. Cepas resistentes ou com resistência intermediária a antibióticos da classe dos aminoglicosídeos e/ou β-lactâmicos foram isoladas neste estudo. Concluiu-se que os isolados de P. aeruginosa foram capazes de produzir biofilme nas matrizes estudadas e apresentaram resistência a antimicrobianos. Metade das amostras apresentou qualidade microbiológica insatisfatória, principalmente devido à contaminação por P. aeruginosa (47,5%).

This study evaluated biofilm formation and antimicrobial susceptibility of Pseudomonas aeruginosa isolated to evaluate the microbiological quality of 80 natural mineral water samples sold in 20 L bottles. The quantity of P. aeruginosa and enterococci was assessed, including total coliforms, thermotolerant coliforms and sulfite-reducing clostridia (SRC). Biofilm production from P. aeruginosa was evaluated in brain heart infusion broth (BHI) and sterile natural mineral water at temperatures of 25 and 35ºC for 24 and 48 h. Antimicrobial susceptibility tests were performed using the agar diffusion method (Kirby-Bauer). Of the 80 samples analyzed, 40 (50%) presented unsatisfactory microbiological quality according to RDC no. 275/05. Thirty-eight (47.5%) samples presented P. aeruginosa, nine (11.2%) total coliforms, four (5.0%) SRC and one (1.2%) thermotolerant coliform. Sixteen P. aeruginosa strains (51.6%) were classified as non-adherent or weakly adherent, both in BHI as in mineral water. However, five strains (16.1%) were strongly adherent in the two matrices, mainly in BHI at the temperature of 25ºC. The study also isolated resistant or intermediate resistant strains to antibiotics of aminoglycosides and/or β-lactams classes. It was concluded that P. aeruginosa isolates were able to produce biofilm in the studied matrices and presented resistance to antimicrobials. Half of the samples presented unsatisfactory microbiological quality, mostly due to P. aeruginosa contamination.

The genus Listeria is composed of six species of which Listeria monocytogenes is considered the single pathogenic species that causes listeriosis in humans. Of the 13 serovars of L. monocytogenes, 1/2a, 1/2b and 4b are responsible for the majority of clinical cases. The aim of this work was to detect L. monocytogenes in the cerebrospinal fluid sample of premature newborns and to characterize this sample using biotyping, serotyping and molecular typing. The results indicated the presence of L. monocytogenesin the clinical sample studied. Moreover, the isolate was identified as the 4b serovar that was characterized by the presence of a unique 691 bp band after analysis using the Multiplex-PCR technique. The results of repeated Multiplex-PCR and sequencing have indicated that the L. monocytogenes isolate was an atypical 4b serovar, which is the first time this finding has been reported.