CORYNEBACTERIUM-PSEUDODIPHTHERITICUM - A RESPIRATORY-TRACT PATHOGEN

From January 1986 through February 1993, there were 16 episodes of res piratory infection due to Corynebacterium pseudodiphtheriticum in 13 p atients. The ages of patients ranged from 24 to 77 years; the ratio of male to female patients was 3:1. One patient had three episodes of in fection, and another patient had two. In one patient, who died of diss eminated intravascular coagulation, the level of IgG was low. One pati ent was receiving prednisolone when the infection occurred. In two cas es a mixed infection with Streptococcus pneumoniae was noted, Sputum c ultures yielded C, pseudodiphtheriticum (greater than or equal to 10(7 ) cfu/mL), An increased neutrophil response in the sputum of infected patients was observed, Gram staining and electron microscopy of sputum showed phagocytosis of C. pseudodiphtheriticum by the neutrophils. EL ISAs also showed an increase in the level of immunoglobulin against C, pseudodiphtheriticum after infection. Tests for determination of MICs of antibiotics revealed that C, pseudodiphtheriticum isolates were su sceptible to ampicillin, amoxycillin/clavulanic acid, cefazolin, cefur oxime, ceftazidime, and imipenem, All strains were resistant to nalidi xic acid; borderline susceptibility to ofloxacin, norfloxacin, and cip rofloxacin was noted, We suggest the use of beta-lactam antibiotics in the treatment of infection with C, pseudodiphtheriticum.