To assess whether methicillin resistance is a microbial characteristic associated with deleterious clinical outcome, we performed a cohort study on 908 consecutive episodes of Staphylococcus aureus bacteremia and a case-control study involving 163 pairs of patients matched for preexisting comorbidities, prognosis of the underlying disease, length of hospitalization, and age. Of 908 bacteremic episodes, 225 (24.8%) were due to methicillin-resistant S. aureus (MRSA). Multivariate analysis did not reveal that methicillin resistance was an independent predictor for mortality when shock, source of bacteremia, presence of an ultimately or rapidly fatal underlying disease, acquisition of the infection in an intensive care unit (ICU), inappropriate empirical therapy, female sex, and age were taken into account. Nonetheless, methicillin resistance was an independent predictor for shock. The case-control study could not confirm that shock was linked to MRSA when prior antimicrobial therapy, inappropriate treatment, ICU residence, and female sex were considered. Our data suggest that cohort studies tend to magnify the relationship of MRSA with clinical markers of microbial pathogenicity and that this effect is a shortcoming of these kind of studies that is caused by inadequate control for underlying diseases.

A high incidence of herpes zoster was noticed among patients with AIDS, shortly after addition of a protease inhibitor to their baseline treatment with nucleoside analogue reverse-transcriptase inhibitors. Within a median follow-up of 64 weeks (range, 34-103 weeks), 14 patients (7%) had a first episode or a recurrence of herpes zoster (6.2 episodes per 100 patient-years). No episodes of zoster were diagnosed before week 4. Twelve episodes (86%) occurred between weeks 4 and 16. The risk of zoster was independent of age, sex, type of protease inhibitor, and CD4+ lymphocyte count and viral load at baseline and month 1. A CD8+ lymphocyte proportion at baseline of > 66% (hazard ratio [HR], 10.6; 95% confidence interval [CI], 3.4-33.1) and an increase in CD8+ lymphocyte proportion at month 1 of > 5% (HR, 32; 95% CI, 8.1-126.4) were independently associated with the risk of herpes zoster. These data might be clinically useful for determining transient prophylaxis for those patients at high risk.

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From November 1983 to April 1990, disseminated candidiasis was diagnosed in 83 heroin addicts at our institution. All patients had consumed brown heroin diluted in fresh lemon juice. Sixty-two (75%) had skin lesions, 41 (49%) had ocular lesions, and 35 (42%) had one or several costochondral tumors. Candida albicans was grown in culture or histopathologically identified in 34 cases (41%). The patients who had only cutaneous lesions were treated with ketoconazole, and they were all cured. The patients with ocular involvement received systemic amphotericin B with or without oral flucytosine; 29 of these patients developed varying degrees of vision loss. The method of treatment of costochondral tumors was not uniform; in 14 cases the lesions were resected. The one patient who died developed endocarditis involving the aortic valve. Cases of pleuropulmonary involvement, spondylitis, and large-joint arthritis have also been described among the 300 cases reported in the reviewed literature. This is a new syndrome of candidal infection in drug addicts who use brown heroin; ocular lesions are the most harmful manifestation, and loss of vision is the major sequela.

Quinolone-resistant (QR) Escherichia coli may have lower invasive capacity than does quinolone-susceptible E. coli. To evaluate this, we prospectively collected data regarding all cases of E. coli invasive urinary tract infections (IUTI) in 669 adults admitted to the Infectious Diseases Unit of our hospital during a 3-year period, as well as 10,950 patients with cystitis or asymptomatic bacteriuria who presented to the outpatient clinic during a 1-year period. QR E. coli was isolated in 20% of patients with cystitis, compared with 8% of those with IUTI (P<.05). The proportion of E. coli isolates that were quinolone resistant was similar in patients with bacteremic and nonbacteremic IUTI. The factors of urinary manipulation and structural abnormalities were independently associated with the presence of quinolone resistance. Old age was the only variable independently associated with blood invasion. QR E. coli is less likely to produce invasive disease (pyelonephritis and prostatitis) than is quinolone-susceptible E. coli. However, once pyelonephritis or prostatitis have developed, there is no difference in the incidence of bacteremia.