The influence of different culture media on Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus biofilm formation

Microorganisms such as Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus are frequently isolated in samples of urinary, blood, intestinal, and respiratory infections, among others. These bacteria are also associated with microbial biofilm formation. E. coli, P. aeruginosa, and S. aureus biofilm infections are particularly hard to manage and often associated with nosocomial problems. This study investigated the influence of different culture media on E. coli, P. aeruginosa, and S. aureus biofilm formation. Bacterial performance was evaluated in brain heart infusion broth, Mueller-Hinton broth, or tryptic soy broth, with or without supplementing with different glucose levels (1-5%). The study quantified biofilm biomass and the count of viable biofilm colonies. This is the first study that compares the biofilm formation of E. coli, P. aeruginosa and S. aureus in polystyrene using different culture media and with different glucose concentrations. The most robust growth of E. coli, P. aeruginosa, and S. aureus occurred in brain heart infusion broth supplemented with 5% glucose, Mueller-Hinton broth without glucose, and tryptic soy broth with 2% glucose, respectively. Our data demonstrate that behavioral and morphological characteristics of each bacterium require a specific broth to enhance the growth of these microorganisms. These findings will contribute to future tests for therapeutic alternatives with anti-biofilm potential.

Detection and characterization of Bacillus cereus isolated from the dialysis fluid

ABSTRACT In this study, B. cereus was detected in dialysis fluids within international parameters (ultrapure - maximum limit of 0.1 CFU/mL for heterotrophic bacteria count) by analyzing the pellet obtained through the centrifugation method. We also investigated the ability of the B. cereus isolate to form a biofilm at different temperatures, the production of virulence factors, and the susceptibility to commercial antimicrobial agents. This study demonstrated a high ability of B. cereus to persist in the hemodialysis system, which can be explained by its broad ability to produce a biofilm at 25 °C, its relevant production of virulence factors, such as β-hemolysin, lecithinase and cereulide, and its important resistance pattern to antimicrobial drugs. In conclusion, these new findings expand the understanding that this microorganism should not be neglected and new methods for tracking it should be considered.

Análise microbiológica da ocorrência da contaminação bacteriana da mesa cirúrgica comparando o TNT gramatura 20 e gramatura 40 / Microbiological analysis of occurrence of bacterial contamination of surgical table comparing 20 thickness and 40 thicknes

A limpeza e desinfecção das superfícies operatórias fixas e partes expostas do equipo odontológico reduzem, significativamente, a contaminação. Este estudo teve como objetivo avaliar se há contaminação da mesa cirúrgica, ao se utilizar o TNT esterilizado nas gramaturas 20 g/m² e 40 g/m². Materiais e Métodos: O trabalho constituiu-se de 2 grupos, compostos por 30 amostras (campos cirúrgicos) para cada grupo. Após a desinfecção prévia das mesas cirúrgicas, foram colocados campos de TNT. No grupo 1, foi utilizado TNT gramatura 20, e no grupo 2, gramatura 40. A coleta das amostras dos dois grupos foi realizada logo após a colocação dos campos cirúrgicos (tempo 1) e 1 hora após (tempo 2). Resultados: Em relação à ocorrência de contaminação bacteriana, não houve diferença estatisticamente significativas entre tempo de coletas. Mesmo com os cuidados de desinfecção da mesa e paramentação adequada, esses campos não foram totalmente eficazes. Conclusão: A amostra do TNT gramatura 40, tanto no início da cirurgia quanto 1 hora após, obteve melhores resultados, comparando-se com o TNT gramatura 20 sem diferenças estatísticas... (AU)

The cleaning and disinfecting fixed operative surfaces and exposed parts of the dental unit significantly reduces contamination. This study aimed to assess whether there is contamination of the surgical table to use the TNT sterilized in the weights 20 g/m² and 40 g/m². Materials and Methods: The study consisted of two groups, composed of 30 samples (drapes) for each group. After prior disinfection of surgical tables were placed TNT fields. Group 1 was used TNT weight and 20 in group 2 weight 40. The sample collection from both groups was held soon after the placement of surgical fields (time 1) and 1 hour after (time 2). Results: Regarding the occurrence of bacterial contamination, there was no statistically significant difference between time of collection. Even with the disinfecting care of the table and adequate scrub, these fields have not been fully effective. Conclusion: Thus, the sample weight of the TNT 40, both at the beginning of surgery, as 1 hour, better results compared to the TNT weight 20 without statistical differences... (AU)