Emergence of Resistance of Providencia stuartii to Multiple Antibiotics: Speciation and Biochemical Characterization of Providencia

Abstract

From October 1972 through April 1973 isolates of Providencia with multiple resistance to antibiotics were obtained from patients in the Burn Unit of Los Angeles County/University of Southern California Medical Center. A comparison of the in vitro susceptibilities against nine antibiotics was made of the Burn Unit strains with 20 strains isolated from patients on other services. Cultures from the Burn Unit were resistant to most antibiotics, including kanamycin, streptomycin, gentamicin, and tobramycin: they remained susceptible only to the experimental antibiotic, amikacin. Biochemical reactions permitted speciation of the 114 strains. Strains that fermented inositol and conformed to the definition of Providencia Stuartii, demonstrated marked resistance to antibiotics. Those characterized as Providencia alcalijaciens were susceptible to most antibiotics. These observations signal the necessity for speciation of Providencia in the laboratory and emphasize again the hazard of resistance among coliforms in isolated nosocomial environments.