DIFFERENTIAL EFFECTS OF TEMPERATURE AND pH ON THE ANTIBIOTIC RESISTANCE OF PATHOGENIC AND NON-PATHOGENIC STRAINS OF ESCHERICHIA COLI

Abstract

Objective: Main aim of the present study was to determine differential effects of temperature and pH on the sensitivity/resistance of bacteria against ciprofloxacin and chloramphenicol.

Methods: Both the bacterial strains were subjected to MIC determination. These were subjected to the varying values of environmental stresses including temperature and pH. The growth was monitored using spectrophotometer and degree of resistance if gained was screened over the agar dilution plates. Morphological changes were also observed in the shape and size of bacteria using light microscope at 1000X.

Results: Present study enlightened the facts that pathogenic strain and a non-pathogenic strain of E. coli behave differently for factors like pH and temperature. It is not so that if non-pathogenic E. coli gains resistance to antibiotic under a specified condition of temperature and pH, then the pathogenic strain would also gain resistance the same way. It was noticed in present study that non-pathogenic E. coli is not very sensitive to the antibiotics, but the pathogenic E. coli is much more sensitive to antibiotics like ciprofloxacin, however it is easy for the pathogenic strain than the non-pathogenic one to gain resistance to antibiotic if proper environmental condition is made available like temperature of 30 °C and pH 6.5 (which appeared to be the best value of respective stresses regarding gain of resistance). However, it is not so that two drugs like ciprofloxacin and chloramphenicol acts with efficacy in similar environmental conditions. Similarly, the bacteria also gains resistance to these drugs under different environmental conditions. The study proved pivotal in concluding that temperature alone can't induce resistance in the bacteria against the antibiotic, also pH plays more significant role in the efficacy of antibiotic and the resistance acquired against it.

Conclusion: Both pathogenic and non-pathogenic strains of E. coli behave differently against the abiotic stresses and there may exist a different mechanism of stress regulation in both the strains, which may get even more complicated if the combination of stresses are taken into consideration. These points may help us to understand and get a permanent solution for antibiotic resistance of bacteria hence making pathogens sensitive and non-pathogenic/useful bacteria resistant to the antibiotics.