Keith Krasinski

Prevalence of Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus in the Community

Recent reports indicate that community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are increasing and may now involve persons without risk factors predisposing for acquisition. To estimate the extent of community MRSA in New York City, the prevalence of S. aureus and MRSA nasal colonization in a well-patient population of 500 children and guardians was determined. The prevalence of S. aureus nasal carriage was 35% for children and 28% for guardians. One person with predisposing risk factors was colonized with an MRSA, which was identified as the predominant clone found in New York City hospitals. A high degree of methicillin-susceptible S. aureus strain diversity was noted, with no apparent selection for specific clonal types. Thus, MRSA colonization is not ubiquitous in persons without predisposing risk outside of the health care environment. Bacterial competition and a lack of strong selection may limit the community spread of MRSA and can account for its sporadic distribution.

Bacterial infections in human immunodeficiency virus-infected children.

A retrospective review of 71 children infected with human immunodeficiency virus cared for over a 3.5-year period revealed that 44 of 71 (63%) required a bacterial culture and 27 of 71 (37%) had bacteriologically documented infection. There were 125 episodes in 27 patients. Pneumonia (24 of 125 (19%)), upper respiratory tract syndromes (23 of 125 (19%)), urinary tract infection (24 of 125 (19%)) and wound infection (12 of 125 (10%)) were the most common syndromes identified. Bacteremic infections occurred in 35 of 125 (28%), and in 17 of 125 (14%) no other primary source could be identified. Pneumococci (11 of 35 (31%)) and Salmonella (4 of 35 (11%)) were the most common blood isolates; however, a wide spectrum of Gram-positive and Gram-negative pathogens were recovered. Bacterial pneumonia directly contributed to the death of 4 patients, in whom pneumonia caused by Pneumocystis carinii (2), cytomegalovirus (1) or varicella-zoster virus (1) also coexisted, respectively. Absolute T4 counts less than 400 and depressed lymphocyte-proliferative responses to diphtheria and tetanus toxoids, Candida antigen and pokeweed mitogen correlated with the occurrence of bacterial infection in human immunodeficiency virus-infected children. Although bacterial infections are a frequent cause of morbidity in human immunodeficiency virus-infected children, they are usually treatable.

Varicella-zoster virus infections in children infected with human immunodeficiency virus.

Primary varicella-zoster (VZ) infection in eight children with perinatally acquired human immunodeficiency virus infection tended to be severe, prolonged, complicated by bacterial infections and in one case fatal. Depletion of CD4-lymphocytes was associated with chronic and recurrent VZ infection. In some patients convalescent VZ antibody titers were low and did not correlate with recurrence of VZ lesions. Administration of acyclovir appeared to be beneficial in suppressing VZ in human immunodeficiency virus-infected children with primary or recurrent VZ infection.

Nosocomial fungal infection during hospital renovation.

Nosocomial fungal pulmonary infections (Zygomycetes, Aspergillus sp.) developed in two premature infants in a special care unit (SCU) adjacent to an area of renovation. Inspection showed that inadequate barriers permitted the passage of airborne particles between the two areas, and cultures confirmed a significantly higher (p less than or equal to 0.05) density of mold spores in the SCU (0.88 cfu per hour per settling plate) compared to a construction-free comparison area (0.22 cfu per hour per settling plate). The major source of mold was the dust above the hospitals false ceiling. In another construction area, imperious barriers were shown to effectively restrict the dispersal of mold. Our experience adds Rhizopus to Aspergillus as a possible cause of construction-related nosocomial infection. Sporadic episodes will continue to occur until the hazards of renovation are appreciated and effective preventive measures are routinely instituted.

HIV-1 among Inner City Dually Diagnosed Inpatients

The objectives of this study were to investigate HIV-1 seroprevalence and risk factors, disease progression, and awareness of HIV-1 serostatus in a population of inner city, substance using, psychiatric inpatients. To pursue these goals, we tested 118 (103 M, 15 F) dually diagnosed, acute care inpatients for HIV-1 antibodies and administered structured interviews. Twenty-seven (23%, including 24 M and 3 F) of the subjects were HIV-1 seropositive. Seropositivity was twice as great among intravenous drug users and men who had sex with other men as among patients not belonging to either of these two groups. Logistic regression analysis among male subjects revealed a significantly elevated HIV-1 risk associated with a primary diagnosis of depression (odds ratio adjusted for age, race, and presence of an AIDS risk behavior = 4.2, 95% confidence interval = 1.1, 16.5; p = 0.04). Less than half of the seropositives knew their HIV-1 status prior to this study, one had AIDS and four had two or more constitutional symptoms of AIDS. The high rate of seropositivity in this indigent, dually diagnosed population presents challenges to the health-care community. That few individuals had HIV-1 related symptoms may have implications for other treatment settings.

Antibody responses to bacterial toxoids in children infected with human immunodeficiency virus

Infection with human immunodeficiency retrovirus (also known as HTLV III, LAV,. and ARV) can produce a spectrum of immunologic perturbations ranging from no obvious deficit to severe combined acquired immune deficiency. Adults with acquired immune deficiency syndrome are likely to have lymphopenia and severe cell-mediated immunodeficiency, with a dramatic deficiency of helper T cells. Adults also have hypergammaglobulinemia and diminished capacity to produce antibody after primary or booster immunizations? Even asymptomatic HIV-infected adults have defective B-lymphocyte function as measured by a variety of in vitro assays. 2 In chiidren, HIV infection produces a similar spectrum of immunologic perturbations. A recent study of sick children with AIDS has demonstrated blunted antibody responses to bacteriophage phi X174 after prinmry and secondary immunizations. In addition, class switching (IgM to IgG) was generally absent and antibody responses to pneumococcal vaccine and tetanus toxoid were also diminished? We examined 17 children with HIV infection, who had received at least three immunizations with diphtheriatetanus-pertussis vaccine, for the presence of humoral and ceil-mediated immune responses to diphtheria and tetanus toxoids. These children had neither, a history of opportunistic infection nor biopsy-proved lymphocytic interstitial proliferation at the time of study. METHODS

Increased transmission of vertical hepatitis C virus (HCV) infection to human immunodeficiency virus (HIV)-infected infants of HIV- and HCV-coinfected women.

The transmission of perinatal hepatitis C virus (HCV) infection was studied retrospectively in 62 infants born to 54 HCV- and human immunodeficiency virus (HIV)-coinfected women enrolled in a prospective natural history study of HIV transmission. Infant HCV infection was assessed by nested RNA polymerase chain reaction. The overall rate of vertical HCV transmission was 16.4% (9/62). Most HCV-infected children did not develop antibodies to HCV. The rate of HCV infection was higher among HIV-infected infants (40%) than among HIV-uninfected infants (7.5%; odds ratio, 8.2; P = .009). This difference in transmission was not related to differences in maternal HCV load, as measured by branched DNA assay, or mode of delivery. Why HIV-infected infants of HCV- and HIV-coinfected women have significantly higher rates of perinatal HCV transmission remains to be elucidated. The rate of HCV transmission in HIV-uninfected infants of HCV- and HIV-coinfected women is similar to that reported for infants born to HIV-seronegative mothers.

Human-immunodeficiency-virus infections in infants negative for anti-HIV by enzyme-linked immunoassay.

Of 85 children with human-immuno-deficiency-virus (HIV) infection based on clinical (opportunistic infection), epidemiological (mother a drug addict or known to be HIV infected), and immunological (helper-T-cell deficiency and impaired proliferative response to pokeweed mitogen) features, 9 were found to lack antibody to HIV as measured by a commercial enzyme-linked immunoassay (ELISA). All 9 children had detectable levels of HIV antigen in simultaneous plasma specimens, measured by a sensitive antigen-capture ELISA. The use of the western blot assay and an ELISA with recombinant HIV antigens was able to identify HIV infection in 4 of the 9 children.

Maternal predictors of perinatal human immunodeficiency virus transmission

&NA; This analysis sought to identify characteristics of pregnant human immunodeficiency virus type 1 (HIV‐1)‐infected women that predict mother‐to‐child HIV‐1 transmission. Pregnant and immediately postpartum women at risk for HIV were enrolled at obstetric and pediatric care settings in New York City from 1986 to 1992. Demographic and behavioral characteristics, clinical illness, T lymphocyte subsets, immunoglobulin concentration and syphilis serology were collected on the women. Infants were followed to determine HIV infection classification according to Centers for Disease Control and Prevention criteria for HIV‐1 in children. Transmission rates were calculated for women who gave birth more than 15 months before the analysis. Of 172 HIV‐1‐infected women with known outcome 49 (28%) had infected infants. The transmission rate (TR) was significantly higher among women with <280 CD4+ cells/&mgr;l (lowest CD4+ quartile) than with CD4+ counts >280 (48% vs. 22%; P = 0.004; odds ratio, 3.4; 95% confidence interval (1.5, 7.8)); a similar trend was seen by CD4+% quartile. No difference in TR was seen comparing women by CD8+ count quartile but marginally higher TR was seen among women with CD8+% ≥51% than with CD8+% <51% (TR = 41% vs. 24%; P = 0.076; odds ratio, 2.2; confidence interval (1.0, 5.1)). The highest TR, 62%, was seen in women with both CD8+ count above the median and CD4+ count in the lowest quartile. No significant difference in TR was seen between women with and without HIV‐related illness, although the TR was 53% among women hospitalized in the previous year for pneumonia compared with 25% in others (P = 0.03). TR was somewhat lower in women who delivered by cesarean section than vaginally (entire cohort: 18% vs. 32%, P = 0.11; prenatal enrollees only, 17% vs. 38%, P = 0.045). No factor or combination of factors was both highly sensitive and specific for predicting mother‐to‐child HIV transmission. A possible relationship between transmission and mode of delivery deserves further investigation.

Screening for respiratory syncytial virus and assignment to a cohort at admission to reduce nosocomial transmission.

To limit nosocomial spread of respiratory syncytial virus (RSV) infection, a longitudinal intervention trial was instituted. Nasal secretions or washes were screened for RSV antigen by enzyme-linked immunosorbent assay, and patients were assigned to an RSV-infected or an RSV-uninfected cohort. The baseline (preintervention) rate of 7.17 nosocomial cases of RSV per 1000 patient-days of care was used for comparison. Despite continued infections in the community after screening was initiated, there were no cases of RSV infection in 1880 patient-days of care for 3 months (p = 0.039). During the fourth month, an RSV-infected child was erroneously assigned to the RSV-uninfected cohort, and three nosocomial cases occurred--5.33/1000 patient-days of care (p = 0.286). Overall, there were three nosocomial RSV infections in 2443 patient-days of care in the 1987 season after screening was introduced--1.23/1000 patient-days of care (p = 0.026). In the subsequent RSV season, there was one nosocomial case--0.461/1000 patient-days of care for 3 months (p = 0.0074). During the same period, nosocomial cases of RSV were observed in the pediatric and neonatal intensive care units, where assignment to a cohort was not possible. We conclude that entry into a cohort at the time of admission, on the basis of prospective RSV screening by enzyme-linked immunosorbent assay, effectively reduces nosocomial transmission of RSV.