Effect of Temperature on Antimicrobial Susceptibilities of Pseudomonas Species Isolated from Drinking Water

Summary

The susceptibility of 20 strains of Pseudomonas species isolated from drinking waters (4 P. aeruginosa, 7 P. fluorescens, 5 P. stutzeri, 1 P. maltophilia, 1 P. cepacia, 1 P. putida and 1 P. pickettii) to a variety of antibiotics (gentamicin, amikacin, azlocillin, cefotaxime, chloramphenicol and polymyxin B) were determined by Stoke’s method at 20°C, 30°C, 37°C and 42°C.

Minimum inhibitory concentrations (MIC) were determined for aminoglycosides on Mueller-Hinton agar at the above temperatures. There was a significant difference in susceptibility between 20°C or 30°C (most resistant), 37°C (more susceptible) and 42°C (most susceptible) to gentamicin and to a lesser degree to amikacin for P. maltophilia, P. cepacia and most strains of P. fluorescens. The P. aeruginosa, P. stutzeri, P. putida and P. pickettii strains showed no difference in susceptibility at 20°C, 30°C, 37°C and 42°C. The need for standardized conditions with special regard to temperature when antibiotic susceptibility tests are performed for P. maitophilia, P. cepacia and P. fluorescens strains is stressed.

Key words:

• Pseudomonas species
• drinking water
• susceptibility testing
• antibiotic susceptibility testing