THE PRESENCE OF -LACTAMASE PRODUCING ORGANISMS IN THE THROATS OF NORMAL PEOPLE AND PATIENTS WITH SYMPTOMS OF STREPTOCOCCAL PHARYNGITIS

Evans, Christopher M.

4056 53rd Ave South St. Petersburg, FL 33711

The purpose of this study was to discover the incidence of -lactamase producing organisms in asymptomatic patients, and patients displaying symptoms of pharyngitis.

There were two phases to the original study. In phase one, the throats of fifty asymptomatic people were cultured aerobically and anaerobically. All organisms were isolated, identified, and tested for -lactamase production. The percentages of -lactamase producing organisms were tabulated in this population. In phase two, patients who displayed characteristics of pharyngitis were similarly cultured, and rates of group A Streptococcus and -lactamase producing organisms were identified. Patients with beta hemolytic group A Streptococcus pyogenes were treated as usual with penicillin and returned for a follow up proof-of-cure culture. This allowed comparison of the cure rates in patients with group A S. pyogenes pharyngitis infections with and without the presence of -lactamase producing organisms.

Twenty of one hundred (twenty percent) asymptomatic patients were carriers of -lactamase producing organisms. Of these organisms eighty percent were Staphylococcus aureus, ten percent were gamma Neisseria, and ten percent were Pseudomonas aeruginosa. Two percent of the asymptomatic people harbored beta hemolytic Streptococcus pyogenes. In phase two, Twenty percent of patients with pharyngitis cultured -lactamase producing organisms. In this population, ten percent had beta hemolytic group A Streptococcus pyogenes. This number was too small to allow comparison of cure rates in patients with beta hemolytic streptococcal pharyngitis between those with and without -lactamase producing organisms. The prevalence of B-lactamase producing organisms in patients with pharyngitis suggests penicillin is not the drug of choice.