Alan A. Pollock

Mycobacterium avium-intracellulare: A Cause of Disseminated Life-Threatening Infection in Homosexuals and Drug Abusers

Five men developed disseminated infection with Mycobacterium avium-intracellulare. These patients all lived in the New York City area and presented with their illnesses between January 1981 and September 1981; four were homosexual and one was an intravenous drug abuser. Four patients died. All five patients had defects in the cell-mediated immune response. The infections were characterized histopathologically by poor or absent granulomatous tissue reaction. Clinical isolates of M. avium-intracellulare from all five patients agglutinated commonly used antimycobacterial drugs. The spectrum of opportunistic infections among populations of homosexuals and drug abusers should be expanded to include disseminated disease due to M. avium-intracellulare.

Netilmicin Therapy of Gentamicin-Sensitive and -Resistant Gram-Negative Infections

Netilmicin, a semisynthetic analog of gentamicin C1a, was administered to 24 patients for treatment of serious gram-negative infections. Among organisms isolated, 45% were gentamicin-resistant and 55% were gentamicin-sensitive. Cure was achieved in 7 of 8 bacteremias, 13 of 18 urinary tract infections, 2 of 3 wound infections, 0 of 3 pulmonary infections (two had bronchogenic carcinoma), and one infected ascites. In two patients, bacteremias were eradicated, but bacteremia due to a sensitive organism persisted in the presence of high urinary concentrations of netilmicin. The clinical and bacteriologic cure rate was 66%. Effective drug concentrations were demonstrated in serum, pleural fluid, and ascitic fluid. The drug also penetrated bile, although in lower concentrations. Serum creatinine elevations ≥ 0.5 mg/dl occurred in five patients (21%) during treatment. Changes of 15 db or greater in two or more frequencies were noted in three of 13 patients with serial audiograms (23%). Reversible vestibular toxicity occurred in one patient who had prior gentamicin treatment, a single kidney, and peak serum netilmicin level of 18.5 μg/ml. Netilmicin is an effective aminoglycoside in the treatment of serious gram-negative infections, including many that may be due to gentamicin-resistant organisms. Both ototoxicity and nephrotoxicity occur under those circumstances predisposing to toxicity of other aminoglycosides.

Case Report: Penicillin Sensitive Nutritionally Variant Streptococcal Endocarditis: Relapse After Penicillin Therapy

Studies to date have indicated that nutritionally-variant streptococci (NVS) causing bacterial endocarditis are frequently inhibited but not killed by low concentrations of penicillin. We report a patient with endocarditis due to a NVS strain which was killed in vitro by penicillin at a concentration of 0.09 microgram/ml. Despite therapy with intravenous penicillin for four weeks, the infection relapsed and was then cured by combined penicillin-gentamicin in therapy. In vitro studies demonstrated a synergistic effect of these two antibiotics. This experience suggests that combination therapy with penicillin and an aminoglycoside may be required for cure of all cases of nutritionally-variant streptococcal endocarditis regardless of in vitro susceptibility to penicillin.