Needham, Gerald M.

THE TUBERCLE bacillus is the most common cause of lymphadenitis with caseous necrosis. Such a condition in the cervical region, while less frequent than in previous decades, still occurs occasionally. While other agents, for example, Coccidioides, Histoplasma, Brucella, Pasteurella and Miyagawanella, are known to produce a similar histopathologic reaction, they are not commonly associated with lesions in the cervical lymph nodes, especially in children. Therefore the finding of acid-fast bacilli in such lesions has generally been considered bona fide evidence of tuberculosis, although previous reports from this clinic indicate that such is not necessarily true. It is recognized that there are other acid-fast bacilli, such as the lepra and smegma bacilli, which may or may not cause disease. In 1944 Gellerstedt reported seven cases of tuberculoid skin lesions due to atypical acid-fast bacilli. He considered these to be due to exogenous infection with acid-fast bacilli differing from the organisms found in tuberculosis, and he considered them as possibly saprophytic organisms. In 1948 MacCallum and co-workers reported six cases of skin lesions due to acid-fast organisms that were not Mycobacterium tuberculosis. The lesions did not contain tubercle follicles, giant cells or caseous material. The name "Mycobacterium ulcerans" was applied to these organisms by Australian workers. In 1954 Linnell and Nordén described skin lesions that occurred in 80 boys and girls who used a certain swimming pool in a Swedish town. The etiologic organisms were acid fast, differed from those described by MacCallum and associates and were not lepra bacilli. Guinea pigs injected with these organisms presented no evidence of lesions after 7 weeks.

Three hundred twenty-nine strains of the tribe Klebsielleae were compared by several biochemical tests and by susceptibility to selected antibiotics. Biochemical tests included urease, amino acid decarboxylase, and hydrogen sulfide production; fermentation of lactose and dextrose; motility; and tests in the IMViC (indole, methyl red, Voges-Proskauer, citrate) series. The isolates were: Klebsiella species, 67.5%; Enterobacter species, 28%, and Serratia species, 4.5%. Minimal inhibitory concentrations of cephaloridine, cephalothin, and a new cephalosporin, cephalexin, and of ampicillin were determined by the agar dilution procedure. Cephalosporins at 20 μg/ml or less inhibited 90% of the Klebsiella strains but only 15% of the Enterobacter strains. Ampicillin inhibited 27% of Enterobacter strains and 17% of Klebsiella strains. Serratia isolates were insensitive to the cephalosporins and ampicillin. The results suggest that precise identification of this group to the generic level can be accomplished readily in the clinical laboratory and that such information is helpful in the preliminary selection of an antibiotic for treatment of clinical infections.