Cell adhesion and twitching motility influence strong biofilm formation in Pseudomonas aeruginosa

Abstract

In the present study, biofilm formation was quantified in UTI isolates of Pseudomonas aeruginosa (n = 22) using the crystal violet assay and was categorized into; strong (n = 16), weak (n = 4), and moderate (n = 2) biofilm producers. Further experiments were done using strong (n = 4) and weak (n = 4) biofilm producers. Biofilm formation was greater in Luria broth followed by natural urine and artificial urine on silicone and silicone-coated latex. Cell adhesion and twitching motility were greater in strong biofilm producers. The presence of thick biofilm with an increased number of dead and total number of cells of strong biofilm producers was observed using CLSM. The concentrations of exopolymeric substances (eDNA, protein, and pel polysaccharide) were high in strong biofilm producers. FEG-SEM visualization of biofilm produced by strong biofilm producers showed more cells encased in thick biofilm matrix than weak ones. Overall results provide evidence for increased cell adhesion and twitching motility in strong biofilm producers.

Keywords:

• Biofilm
• UTI
• strong
• twitching motility

Acknowledgments

We would like to acknowledge “Confocal Laser Scanning Microscopy (Carl Zeiss LSM 780) Central Facility of IRCC” housed in the BSBE Department of IIT-Bombay. we also acknowledge “Confocal Laser Scanning Microscopy (Carl Zeiss LSM 710) housed in Central Facility at VSI-CMB Department of MSU Baroda”. We thank the Sophisticated Instrumentation Centre for Applied Research and Testing-SICART, Vallabh Vidyanagar for their Scanning Electron Microscope (SEM) facility.

Disclosure statement

The authors declare no conflict-of-interest disclosure.

Supplementary material

Table S1: Primers used in the study for Pili A and Cdr A gene expression in strong and weak biofilm forming isolate.

Supplementary Figure S1: Statistical comparison of biofilm formation by strong and weak biofilm producers (a and b). The Experiment was conducted in three biological experiments for each strain. Error bar indicates standard deviation. Two-way ANOVA was performed for statistical significance were ns p > 0.05, * p < 0.05, ** p < 0.005, *** p < 0.0005.

Supplementary video S1: Twitching motility of strong and weak biofilm producers at 4 h on 1% LA pad.

Supplementary video S2: CLSM image of biofilm formed by strong and weak biofilm producers.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by a research grant from Maharaja Sayajirao University of Baroda (RCC/Dir/2017/335/10). Hiral Patel thanks for CSIR-UGC fellowship-University Grants Commission (UGC). We are also grateful for the infrastructure support to this department under the DST-FIST program of the Government of India and Biotechnology- Teaching Programme.