Glycopeptide resistance among coagulase-negative staphylococci that cause bacteremia: epidemiological and clinical findings from a case-control study.

A 1-year prospective case-control study (ratio of control patients to case patients, 3:1) was performed to assess the incidence, risk factors, and genotypic patterns of bacteremia caused by glycopeptide-resistant coagulase-negative staphylococci (CoNS) and their correlation with hospital glycopeptide use. Among 535 subjects with CoNS bacteremia, 20 subjects had a glycopeptide-resistant strain (19 strains were resistant to teicoplanin and 1 was resistant to both teicoplanin and vancomycin). The percentage of resistant isolates recovered in 1 year was 8% in intensive care units and 3% and 2% in medical and surgical wards, respectively. Genotypic analysis of resistant strains showed different patterns with a high degree of polymorphism. Use of glycopeptides in individual wards was not statistically associated with the percentage of resistance. Previous exposure to beta-lactams and glycopeptides, multiple hospitalization in the previous year, and concomitant pneumonia were significantly associated with the onset of glycopeptide-resistant CoNS bacteremia. Mortality rates were 25% among case patients and 18% among control patients, and they were significantly higher among patients who presented with concomitant pneumonia and a high Acute Physiology and Chronic Health Evaluation III score.

Changes in incidence and risk factors of Mycobacterium avium complex infections in patients with AIDS in the era of new antiretroviral therapies.

The aim of the study presented here was to determine the incidence, risk factors and prognostic indicators of Mycobacterium avium complex (MAC) infection in HIV-infected subjects prior to and after the introduction of highly active antiretroviral therapy (HAART). In the HAART era, the incidence of MAC infection decreased significantly from 3.7 to 0.9 per 100 person-years. Using logistic regression analysis, a high acute physiology and chronic health evaluation (APACHE) III score, a low number of CD4+ cells/ mm3 and a high level of HIV viremia were found to be independent predictors of the risk to develop MAC disease; however, a high APACHE III score was the only prognostic indicator associated with an unfavourable outcome of a disseminated MAC infection. These results indicate that MAC infections, although considerably less frequent in the HAART era, are still responsible for cases of severe disease.

HIV-associated bacteremia: how it has changed in the highly active antiretroviral therapy (HAART) era.

To evaluate the changing characteristics of HIV-associated bacteremia in the highly active antiretroviral therapy (HAART) era, we conducted a prospective case control study, comparing two periods of time, before (period A) and after (period B) the introduction of HAART. In total, 174 patients with bacteremia and 348 controls were studied. By comparing incidence in periods A and B, a statistically significant reduction of bacteremia, from 11.8 to 6.3/100 person-years (PY), was observed (p = .0001). Incidence of hospital-acquired bacteremia decreased from 5.8 episodes/100 PY in period A to 2.4/100 PY in period B (p = .0005). A similar trend was also observed for community-acquired episodes of bacteremia, with a value close to statistical significance. Logistic regression analysis indicated that intravenous drug abuse, central venous catheter (CVC) use, high value on APACHE III score, and neutropenia were independent risk factors for bacteremia in both the study periods. Interestingly, comparing the prevalence of bacteremia risk factors in the two study periods, we observed a significant reduction in the use of CVC (p = .04, period A versus period B) and in neutropenia (p = .04). The crude mortality rate was 31% in period A and 23% in period B (p = not significant [ns]). Logistic regression analysis indicated that an high value of Acute Physiology and Chronic Health Evaluation III (APACHE III) score (p < .001) predicted an increased risk of death. Analysis of prognostic factors of bacteremia did not significantly differ in both the study periods. We conclude that HAART has determined a significant reduction of the incidence and a modification of the characteristics of bacteremia. This reduced incidence may produce a substantial impact on future morbidity and health care costs of patients with HIV.

Nosocomial bloodstream infections in HIV-infected patients: attributable mortality and extension of hospital stay.

A 3-year prospective matched case-control study was performed to investigate the potential risk factors, prognostic indicators, extension of hospital stay, and attributable mortality of nosocomial bloodstream infections in HIV-infected patients. Matching variables were: age, gender, number of circulating CD4+ T lymphocytes, cause of hospital admission, hospitalization in the same ward within the 6 weeks of diagnosis of the case, and length of stay before the day of infection in the case. Eighty-four cases and 168 matched controls were studied. Nosocomial bloodstream infections complicated about 3 of 1000 hospital days per patient in the study period. With step-wise logistic regression analysis, the most important predictors for developing nosocomial bloodstream infections were: increasing value of Acute Physiology and Chronic Health Evaluation (APACHE II) score (p = .001) and use of central venous catheter (CVC) (p = .002). The excess of hospital stay attributable to nosocomial bloodstream infections was 17 days. The crude mortality rate was 43%. The attributable mortality rate was estimated to be 27% (95% confidence interval [CI] = 13%-48%). The estimated risk ratio for death was 3.91 (95% CI = 2.06-7.44). Multivariate analysis identified two prognostic indicators that were significantly associated with unfavorable outcome of bloodstream infections: number of circulating CD4+ T cells <100/mm3 (p = .002) and APACHE II score >15 (p = .01). Nosocomial bloodstream infections are more common in patients with advanced HIV disease. Important cofactors are high APACHE II score and use of CVC. These infections can cause an excess mortality and significantly prolong the hospital stay of HIV-infected patients.