Influence of antibiotics on intestinal tract survival and translocation of environmental Pseudomonas species

Abstract

The environmental release of microorganisms has prompted the investigation of potential health effects associated with their release. In this study, survival and translocation to the spleen and liver of several environmental Pseudomonas spp. were investigated in antibiotic-treated mice. Pseudomonas aeruginosa BC16 and P. maltophilia BC6, isolated from a commercial product for polychlorinated biphenyl degradation; P. aeruginosa AC869, a 3,5-dichlorobenzoate degrader; and P. cepacia AC1100, an organism that metabolizes 2,4,5-trichlorophenoxyacetic acid were examined for their survival capabilities in the intestines of mice dosed with clindamycin, kanamycin, rifampin, or spectinomycin. A mouse intestinal isolate, strain PAMG, was included in the study. Following antibiotic pretreatment (1 mg twice daily for 3 days), mice were dosed by gavage with 109 CFU of each Pseudomonas strain. At the end of the 5-day test period, strains AC869 and PAMG survived in kanamycin-, rifampin-, spectinomycin-, and clindamycin-treated animals. A statistically significant (P < 0.05) increase in survival of strain PAMG was observed in clindamycin-, kanamycin-, and spectinomycin-treated mice for the test period. Treatment with clindamycin or rifampin increased (P < 0.05) survival of strain BC6, an organism resistant to both antibiotics. However, strain BC6 was detected only in rifampin-treated mice at the end of the 5-day test period. Strain BC16, a clindamycin-resistant strain, was detected in clindamycin-treated mice and the untreated control animals. Rifampin had a negative effect (P < 0.05) on strain AC869 and PAMG survival. Translocation to the spleen was observed in spectinomycin- and clindamycin-treated mice but was not detected in kanamycin- or rifampin-treated animals. Depending on the dosed strain, translocation to the liver was observed in animals treated with all four antibiotics and in the untreated mice. However, detection in the liver was generally observed at later time points in antibiotic-treated animals.