The Utilization of the Anti-Quorum Sensing Activity of Bioluminescent Bacteria Isolated from the Freshwater Fish Species of Taal Lake as a Novel Approach in Combatting Antibiotic Resistance

Abstract

INTRODUCTION

Increasing incidences of antibiotic resistance among pathogenic bacteria posed detrimental effects to patients. Bioluminescent bacteria that can be found usually among marine animals are very promising to be a potential source of antimicrobial and anti-quorum sensing compound. However, very few studies reported on the existence of bioluminescent bacteria in freshwater fish species especially those found in the Philippines. Thus, this study aimed at evaluating the anti-quorum sensing activity of the isolated bioluminescent bacteria from freshwater fish species of Taal Lake against swarming motility of Pseudomonas aeruginosa, a common pathogen.

METHODS

In this study, two freshwater fish species, Leiopotherapon plumbeus (Ayungin) and Parachromis managuensis (Dugong) in Taal lake, were found to have bioluminescent bacteria in the gut and in the eyes. Three consistently luminescing BLB isolates from these two species were assayed for antibiotic resistance against gentamycin, erythromycin and ampicillin and assayed for antibacterial bioactivity and screened for anti-quorum sensing against Pseudomonas aeruginosa.

RESULTS

There was no antibiotic resistance exhibited by all the three BLB isolates. Also, antimicrobial activity is also not evident for both the unboiled and boiled cytosolic fractions of the BLB isolates. Interestingly, the anti-qs bioactivity of isolates 1 and 2 are higher at boiled CF with a mean zone of inhibition of 40.60 mm and 42.71 mm respectively. However, in isolate 3, higher anti-qs activity was observed at unboiled CF with a mean zone of inhibition of 33.50mm.

DISCUSSIONS

The BLB isolates did not exhibit any antimicrobial activity against P. aeruginosa. On a lighter side, the isolates were not resistant to antibiotics such as gentamycin, erythromycin, and ampicillin. This indicates that the possible identity of the BLB isolates does not belong to common human pathogens that are now known to be resistant to multiple antibiotics. Most important among the results obtained would be the anti-quorum sensing bioactivity of the BLB isolates to which isolate 3 have the greatest strength measured in terms of zone of inhibition. Thus, this study would alleviate the understanding on the biodiversity of bioluminescent bacteria thriving in the rich freshwaters of Taal Lake. As such, this study could serve as basis for further work on identifying bioluminescent bacteria with anti-quorum sensing activity that could solve problems related to antibiotic resistance.