Sticky Rolls-2020.05.19

Biofilm Related Disease – Biofilm formation represents a protected mode of growth that renders bacterial cells less susceptible to antimicrobials and to killing by host immune effector mechanisms and so enables the pathogens to survive in hostile environments and also to disperse and colonize new niches.

Biofilms: A microbial home – This essay provides a detailed insight into the properties and mechanisms of the development of abnormal condition, detection and removal of these microbial biofilms.

The pH of the Skin Surface and Its Impact on the Barrier Function – The ‘acid mantle’ of the stratum corneum seems to be important for both permeability barrier formation and cutaneous antimicrobial defense. The pH of the skin follows a sharp gradient across the stratum corneum, which is suspected to be important in controlling enzymatic activities and skin renewal. The skin pH is affected by a great number of endogenous factors, e.g. skin moisture, sweat, sebum, anatomic site, genetic predisposition and age.

Temperature and pH Affect the Production of Bacterial Biofilm – The human vagina has an average temperature of about 37.5 °C (99.5 °F) and a healthy pH range of between 3.8 and 4.5. A study looked at biofilm formation of a few different bacteria at 30°C and 37°C, and a pH of 5.5, 7.5 and 8.5.

Findings of the study

Bacterial strains studied were

  • Pseudomonas aeruginosa
  • Klebsiella pneumoniae
  • Vibrio cholerae

These bacteria are known to cause i) general infections in humans including skin and ear infections, ii) pneumonia, and iii) cholera. These bacteria are known to produce biofilms.

The impact of temperature on biofilm production

A decrease in biofilm production was observed at 37°C in eight of the tested strains, compared to production at 30°C. Biofilm production still existed at both temperatures. At normal human vaginal temperatures, biofilm activity exists.

Five of the strains tested had increased biofilm activity at 37°C compared to at 30°C.

The impact of pH on biofilm production

The increases in biofilm formation from a pH of 5.5 were sometimes up to 300 per cent. Increased pH (more alkaline) lead to higher biofilm production.

The results are clear – alkaline pH encourages biofilm formation.