Healthcare-Associated Infections at a Children's Cancer Hospital, 1983-2008.

BACKGROUND: Little is known about the incidence and etiology of healthcare-associated infections in immunosuppressed children. METHODS: Data collected prospectively between 1983 and 2008 were used to analyze changes in the rate, types of infection, and infecting organisms over time in patients treated at a children's cancer hospital. Neutropenia was evaluated as a risk factor. RESULTS: Over the 26-year study period, 1986 healthcare-associated infections were identified during 1653 hospitalizations. The infection rate decreased significantly from 5.6 to 2.0 infections per 100 discharges (P < .01) and from 9.0 to 3.7 infections per 1000 patient-days (P < .01). Bloodstream infections were the most common type of infection (32.7% of all infections). Staphylococci (46.4% of Gram-positive bacteria), Escherichia coli (36.7% of Gram-negative bacteria), and Candida spp. (68.7% of fungi) were the most common pathogens isolated. An absolute neutrophil count (ANC) nadir <100 per mm(3) was significantly associated (P < .0001) with an increased rate of infections compared with higher ANC nadirs. CONCLUSIONS: Despite a steady expansion in hospital capacity and patient encounters over the last 3 decades, rates of healthcare-associated infections decreased significantly at our hospital. These data suggest that sustained decreases in the rate of healthcare-associated infections in immunosuppressed children are possible. An ANC <100 per mm(3) is a risk factor for healthcare-associated infections in this population.

Prophylaxis of Pneumocystis carinii pneumonia with atovaquone in children with leukemia.

BACKGROUND: Despite extensive studies of atovaquone in human immunodeficiency virus (HIV)-infected patients, there is little information about its efficacy as a prophylactic agent for Pneumocystis carinii pneumonia (PCP) in pediatric patients with cancer. Therefore, a retrospective analysis was conducted to determine the incidence of PCP in pediatric patients who received prophylactic atovaquone during treatment for acute leukemia. METHODS: We reviewed the medical records of all patients treated at our institution for acute lymphoblastic leukemia or acute myeloid leukemia between 1994 and 2004. Only patients who were intolerant of trimethoprim-sulfamethoxazole (TMP-SMZ) and received atovaquone prophylaxis were included in the analysis. RESULTS: Eighty-six patients were unable to tolerate TMP-SMZ and received daily atovaquone for PCP prophylaxis. PCP was not diagnosed in any patient who received atovaquone prophylaxis: the upper limit of the 95% confidence interval (CI) was 1.74 per 100 person-years. CONCLUSIONS: Atovaquone is an efficacious alternative for PCP prophylaxis in pediatric patients who have leukemia and are intolerant of TMP-SMZ.

Antibody responses to hepatitis A virus vaccine in HIV-infected children with evidence of immunologic reconstitution while receiving highly active antiretroviral therapy.

BACKGROUND: Human immunodeficiency virus (HIV)-infected patients have weak responses to vaccines and may require revised immunization regimens. We investigated the safety and immunogenicity of 2 doses of hepatitis A virus (HAV) vaccine followed by a booster dose in HIV-infected children receiving stable highly active antiretroviral therapy. METHODS: A total of 235 children with CD4+ T cell percentages > or = 20% received 2 vaccine doses 24 weeks apart, and 117 received a third vaccine dose after 104 weeks. Anti-HAV antibody titers were measured at baseline and at 32, 104, and 112 weeks after the first vaccination. Subjects with antibody titers > or = 20 mIU/mL were defined as being seropositive. High and low antibody responses were defined as titers > or = 250 and <250 mIU/mL, respectively. RESULTS: Of 151 subjects who were HAV seronegative at baseline, 97% seroconverted after 2 vaccine doses, and 47% had low antibody responses. At 104 weeks, 90% of subjects had antibody titers > or = 20 mIU/mL, and those with low antibody responses were more likely to lose protective antibody titers. A third vaccine dose generated significantly higher antibody titers than those observed after the second vaccine dose. Undetectable HIV RNA at baseline was associated with higher anti-HAV antibody titers after the second vaccine dose. Antibody titers after the second and third vaccine doses were weakly correlated with CD4+ T cell percentages at the time when each vaccine dose was administered. In the 45 subjects who were HAV seropositive at baseline, responses to 2 and 3 vaccine doses were higher than those in subjects who were HAV seronegative at baseline, but the responses showed similar correlations. There were no serious adverse events associated with the vaccine. CONCLUSIONS: HIV-infected children with CD4+ T cell percentages > or = 20% responded better to the HAV vaccine if they had undetectable HIV RNA. The standard 2-dose immunization regimen generated low antibody titers with limited persistence. A third vaccine dose was safe and increased the antibody titers, suggesting that an increase in immunizations may be warranted in this population.

The rate of serious bacterial infections among HIV-infected children with immune reconstitution who have discontinued opportunistic infection prophylaxis.

OBJECTIVE: Receipt of highly active antiretroviral therapy is associated with a decrease in the incidence of opportunistic infections (OIs) among HIV-infected adults. The goal of Pediatric AIDS Clinical Trials Group protocol 1008 was to evaluate prospectively the incidence of serious bacterial infections (SBIs) and other OIs after discontinuation of OI and/or Pneumocystis jiroveci pneumonia (PCP) prophylaxis among HIV-infected pediatric subjects who experienced immune reconstitution while receiving stable antiretroviral therapy. METHODS: HIV-infected children and adolescents, 2 to 21 years of age, who had received OI and/or PCP prophylaxis for > or =6 months were enrolled if they had sustained responses (>16 weeks before study entry) to antiretroviral therapy, with CD4+ cell percentages of > or =20% for patients >6 years of age or > or =25% for patients 2 to 6 years of age. Prophylaxis was discontinued at entry. To identify whether any correlation existed between functional immune reconstitution and protection from OIs, subjects were immunized with the hepatitis A virus vaccine. The association between the humoral immune response and the likelihood of developing an OI was evaluated. RESULTS: A total of 235 HIV-infected subjects from 43 participating sites had a median follow-up period of 132 weeks, yielding 547 person-years of observation. Twenty SBIs were observed among 19 subjects, resulting in an incidence rate of 3.66 SBIs per 100 person-years (95% confidence interval: 2.24-5.66 SBIs per 100 person-years). Sixteen of the events were presumed bacterial pneumonia, with 4 proven SBIs. One participant experienced 2 separate pneumonia episodes, of presumed bacterial cause. Ten subjects who developed SBIs had baseline CD4+ cell counts of > or =750 cells per mm3, and 15 had CD4+ cell percentages of > or =25% at the time of their SBIs. Two subjects died as a result of non-SBI-related causes. There were no statistically significant differences in changes over time in CD4+ cell counts or CD4+ cell percentages between subjects who experienced primary end points and those who did not. There was no evidence that baseline protease inhibitor use, gender, race/ethnicity, age, or CD4+ cell count or percentage affected the time to development of a SBI. CONCLUSIONS: OI or PCP prophylaxis can be withdrawn safely for HIV-infected pediatric patients who experience CD4+ cell recovery while receiving stable antiretroviral therapy. More studies are needed to assess the association between antibody responses to neoantigens and the development of SBIs.

Comparison of atovaquone and azithromycin with trimethoprim-sulfamethoxazole for the prevention of serious bacterial infections in children with HIV infection.

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMZ) has been used extensively for the prevention of Pneumocystis carinii (also referred to as "Pneumocystis jiroveci") pneumonia (PCP) and other opportunistic infections in human immunodeficiency virus (HIV)-infected children. Because the efficacy of TMP-SMZ for treatment of bacterial infections is limited, it is sometimes poorly tolerated, and there is risk of emergence of drug-resistant strains associated with widespread use, we evaluated a regimen that included atovaquone and azithromycin. METHODS: A randomized, double-blind, placebo-controlled trial was designed to determine whether atovaquone-azithromycin had equivalent efficacy to TMP-SMZ for the prevention of serious bacterial infections and to compare the long-term tolerance, PCP breakthrough rates, and nonserious bacterial infection rates among HIV-infected children aged 3 months to 19 years. Children qualified for PCP prophylaxis (on the basis of Centers for Disease Control and Prevention recommendations) were randomized to receive atovaquone-azithromycin or TMP-SMZ daily for >or=2 years. RESULTS: Data from 366 of the 369 eligible patients (median duration of follow-up, 3 years) showed that the estimated rates of serious bacterial infection-related events were lower among atovaquone-azithromycin recipients than among TMP-SMZ recipients (17.3 vs. 24.2 events per 100 patient-years; difference, 6.9 events per 100 patient-years; 95% confidence interval [CI], -0.22 to 14.12). Rates for all end points (serious bacterial infection, PCP, Mycobacterium avium complex infection, and serious and nonserious bacterial infection-related deaths) were 19.7 and 27.7 events per 100 patient-years, respectively (difference, 7.9 events per 100 patient-years; 95% CI, -0.28 to 15.54 events per 100 patient-years). The results marginally favored atovaquone-azithromycin therapy statistically. Atovaquone-azithromycin and TMP-SMZ therapies had similar adverse event profiles. CONCLUSIONS: We conclude that, in HIV-infected children, atovaquone-azithromycin is as effective as TMP-SMZ for the prevention of serious bacterial infections and is similarly tolerated.

Effects of immunomodulators on acute Trypanosoma Cruzi infection in mice.

BACKGROUND: Patients who recover from acute trypanosomiasis may succumb to chronic Chagas' disease later in life due to age related immunosuppression, immune system disorders such as AIDS, or during periods of immunosuppressive therapy for organ transplantation. In this study, effects of immunomodulators with diverse properties were examined on the course of an acute and lethal Trypanosoma cruzi infection. MATERIAL/METHODS: ICR (Swiss) mice inoculated with Tulahuen (lethal) strain of T. cruzi were treated with 6 different immunomodulators and the course of infection was studied. RESULTS: Tacrolimus (FK-506) and dexamethasone increased parasitemia in mice when compared to infected untreated animals. Mycophenolate mofetil (RS-61443) and recombinant interleukin-15 (IL-15) treatment decreased the number of parasites but had no effect on animal survival. In contrast, compound L-685-818 (tacrolimus analog) and CD40 ligand (CD40L), provided protection against lethal infection. Mice that survived initial infection were all protected against reinfection. CONCLUSIONS: This study demonstrates the dangers of immunosuppression with tacrolimus and dexamethasone in T. cruzi infected subjects. While mycophenolate did not exacerbate the infection, our data suggest potential therapeutic applications for L-685-818 and CD40 ligand in trypanosomiasis.

Opportunistic infections in AIDS patients.

Preview The type and course of opportunistic infections in patients with AIDS or high-risk HIV infection have changed through the years as a result of therapeutic intervention. Although Pneumocystis carinii pneumonia is still the most common and serious infection, its incidence is declining at the same time that other AIDS-defining illnesses are on the rise. Dr Hughes examines the management of major opportunistic infections and also of tuberculosis, which is becoming more prevalent in association with HIV infection.