Nellie I. Hansen

Neonatal Outcomes of Extremely Preterm Infants From the NICHD Neonatal Research Network

OBJECTIVE: This report presents data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network on care of and morbidity and mortality rates for very low birth weight infants, according to gestational age (GA). METHODS: Perinatal/neonatal data were collected for 9575 infants of extremely low GA (22–28 weeks) and very low birth weight (401–1500 g) who were born at network centers between January 1, 2003, and December 31, 2007. RESULTS: Rates of survival to discharge increased with increasing GA (6% at 22 weeks and 92% at 28 weeks); 1060 infants died at ≤12 hours, with most early deaths occurring at 22 and 23 weeks (85% and 43%, respectively). Rates of prenatal steroid use (13% and 53%, respectively), cesarean section (7% and 24%, respectively), and delivery room intubation (19% and 68%, respectively) increased markedly between 22 and 23 weeks. Infants at the lowest GAs were at greatest risk for morbidities. Overall, 93% had respiratory distress syndrome, 46% patent ductus arteriosus, 16% severe intraventricular hemorrhage, 11% necrotizing enterocolitis, and 36% late-onset sepsis. The new severity-based definition of bronchopulmonary dysplasia classified more infants as having bronchopulmonary dysplasia than did the traditional definition of supplemental oxygen use at 36 weeks (68%, compared with 42%). More than one-half of infants with extremely low GAs had undetermined retinopathy status at the time of discharge. Center differences in management and outcomes were identified. CONCLUSION: Although the majority of infants with GAs of ≥24 weeks survive, high rates of morbidity among survivors continue to be observed.

Early Onset Neonatal Sepsis: The Burden of Group B Streptococcal and E. coli Disease Continues

BACKGROUND: Guidelines for prevention of group B streptococcal (GBS) infection have successfully reduced early onset (EO) GBS disease. Study results suggest that Escherichia coli is an important EO pathogen. OBJECTIVE: To determine EO infection rates, pathogens, morbidity, and mortality in a national network of neonatal centers. METHODS: Infants with EO infection were identified by prospective surveillance at Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Network centers. Infection was defined by positive culture results for blood and cerebrospinal fluid obtained from infants aged ≤72 hours plus treatment with antibiotic therapy for ≥5 days. Mother and infant characteristics, treatments, and outcomes were studied. Numbers of cases and total live births (LBs) were used to calculate incidence. RESULTS: Among 396 586 LBs (2006–2009), 389 infants developed EO infection (0.98 cases per 1000 LBs). Infection rates increased with decreasing birth weight. GBS (43%, 0.41 per 1000 LBs) and E coli (29%, 0.28 per 1000 LBs) were most frequently isolated. Most infants with GBS were term (73%); 81% with E coli were preterm. Mothers of 67% of infected term and 58% of infected preterm infants were screened for GBS, and results were positive for 25% of those mothers. Only 76% of mothers with GBS colonization received intrapartum chemoprophylaxis. Although 77% of infected infants required intensive care, 20% of term infants were treated in the normal newborn nursery. Sixteen percent of infected infants died, most commonly with E coli infection (33%). CONCLUSION: In the era of intrapartum chemoprophylaxis to reduce GBS, rates of EO infection have declined but reflect a continued burden of disease. GBS remains the most frequent pathogen in term infants, and E coli the most significant pathogen in preterm infants. Missed opportunities for GBS prevention continue. Prevention of E coli sepsis, especially among preterm infants, remains a challenge.

Prolonged Duration of Initial Empirical Antibiotic Treatment Is Associated With Increased Rates of Necrotizing Enterocolitis and Death for Extremely Low Birth Weight Infants

OBJECTIVES. Our objectives were to identify factors associated with the duration of the first antibiotic course initiated in the first 3 postnatal days and to assess associations between the duration of the initial antibiotic course and subsequent necrotizing enterocolitis or death in extremely low birth weight infants with sterile initial postnatal culture results. METHODS. We conducted a retrospective cohort analysis of extremely low birth weight infants admitted to tertiary centers in 1998–2001. We defined initial empirical antibiotic treatment duration as continuous days of antibiotic therapy started in the first 3 postnatal days with sterile culture results. We used descriptive statistics to characterize center practice, bivariate analyses to identify factors associated with prolonged empirical antibiotic therapy (≥5 days), and multivariate analyses to evaluate associations between therapy duration, prolonged empirical therapy, and subsequent necrotizing enterocolitis or death. RESULTS. Of 5693 extremely low birth weight infants admitted to 19 centers, 4039 (71%) survived >5 days, received initial empirical antibiotic treatment, and had sterile initial culture results through the first 3 postnatal days. The median therapy duration was 5 days (range: 1–36 days); 2147 infants (53%) received prolonged empirical therapy (center range: 27%–85%). Infants who received prolonged therapy were less mature, had lower Apgar scores, and were more likely to be black. In multivariate analyses adjusted for these factors and center, prolonged therapy was associated with increased odds of necrotizing enterocolitis or death and of death. Each empirical treatment day was associated with increased odds of death, necrotizing enterocolitis, and the composite measure of necrotizing enterocolitis or death. CONCLUSION. Prolonged initial empirical antibiotic therapy may be associated with increased risk of necrotizing enterocolitis or death and should be used with caution.

Very low birth weight preterm infants with early onset neonatal sepsis: The predominance of Gram-negative infections continues in the National Institute of Child Health and Human Development Neonatal Research Network, 2002-2003

Background: Early onset neonatal sepsis (EOS, occurring in the first 72 hours of life) remains an important cause of illness and death among very low birth weight (VLBW) preterm infants. We previously reported a change in the distribution of pathogens associated with EOS from predominantly Gram-positive to primarily Gram-negative organisms. Objective: To compare rates of EOS and pathogens associated with infection among VLBW infants born at centers of the National Institute of Child Health and Human Development (NICHD) Neonatal Research Network during 3 time periods: 1991–1993; 1998–2000; and 2002–2003. Study Design: Prospectively collected data from the NICHD Neonatal Research Network VLBW registry were retrospectively reviewed. Rates of blood culture confirmed EOS, selected maternal and infant variables and pathogens associated with infection were compared between 2002–2003 and 2 previously published cohorts. Results: During the past 13 years, overall rates of EOS have remained stable (15–19 per 1000 live births of infants 401–1500 g). More than one-half of early infections in the 2002–2003 cohort were caused by Gram-negative organisms (53%), with Escherichia coli the most common organism (41%). Rates of group B streptococcal infections remain low (1.8 per 1000 live births). Between 1991–1993 and 1998–2000, there was a significant increase in rates of E. coli infections; but in 2002–2003, there was no significant change (7.0 per 1000 live births). Infants with EOS continue to be at significantly increased risk for death compared with uninfected infants. Conclusion: EOS remains an uncommon but important cause of morbidity and mortality among VLBW infants. Gram-negative organisms continue to be the predominant pathogens associated with EOS.

Infections in VLBW infants: studies from the NICHD neonatal research network

Infection is a serious complication among very low birth weight (VLBW) preterm infants hospitalized in neonatal intensive care units. This article reviews studies from the National Institute of Child Health and Human Development (NICHD) Neonatal Research Network including infection data from observational studies and randomized controlled trials. Blood culture-proven early-onset sepsis (< or = 72 hours) was found in less than 2% of VLBW infants, but was associated with substantial morbidity and mortality. A change in pathogens causing early-onset sepsis among Network patients has been observed over the past decade, with a significant reduction in early-onset group B streptococcal infections, but also a significant increase in early-onset Escherichia coli infections. This change is particularly worrisome, because of the high death rate associated with gram-negative infections, including E coli. Late-onset (> 72 hours) sepsis developed in almost a quarter of infants. The vast majority of infections were caused by gram-positive agents, especially coagulase-negative staphylococci. The risk of late-onset sepsis was inversely related to birth weight and gestational age. Infants with late-onset sepsis were at increased risk for a number of neonatal morbidities, for prolonged hospitalization, and for death. The percentage of deaths attributed to infection increased with increasing postnatal age. The increasing survival of extremely immature infants has resulted in a cohort of infants at prolonged risk for acquired infection. Successful strategies to reduce infections among VLBW infants would improve survival, reduce neonatal morbidity, and reduce the high medical and social costs of VLBW infant care.

The Burden of Invasive Early-onset Neonatal Sepsis in the United States, 2005–2008

Background: Sepsis in the first 3 days of life is a leading cause of morbidity and mortality among infants. Group B Streptococcus (GBS), historically the primary cause of early-onset sepsis (EOS), has declined through widespread use of intrapartum chemoprophylaxis. We estimated the national burden of invasive EOS cases and deaths in the era of GBS prevention. Methods: Population-based surveillance for invasive EOS was conducted in 4 of the Centers for Disease Control and Preventions Active Bacterial Core surveillance sites from 2005 to 2008. We calculated incidence using state and national live birth files. Estimates of the national number of cases and deaths were calculated, standardizing by race and gestational age. Results: Active Bacterial Core surveillance identified 658 cases of EOS; 72 (10.9%) were fatal. Overall incidence remained stable during the 3 years (2005: 0.77 cases/1000 live births; 2008: 0.76 cases/1000 live births). GBS (∼38%) was the most commonly reported pathogen followed by Escherichia coli (∼24%). Black preterm infants had the highest incidence (5.14 cases/1000 live births) and case fatality (24.4%). Nonblack term infants had the lowest incidence (0.40 cases/1000 live births) and case fatality (1.6%). The estimated national annual burden of EOS was approximately 3320 cases (95% confidence interval [CI]: 3060–3580), including 390 deaths (95% CI: 300–490). Among preterm infants, 1570 cases (95% CI: 1400–1770; 47.3% of the overall) and 360 deaths (95% CI: 280–460; 92.3% of the overall) occurred annually. Conclusions: The burden of invasive EOS remains substantial in the era of GBS prevention and disproportionately affects preterm and black infants. Identification of strategies to prevent preterm births is needed to reduce the neonatal sepsis burden.

INCIDENCE OF TUBERCULOSIS IN THE UNITED STATES AMONG HIV-INFECTED PERSONS. THE PULMONARY COMPLICATIONS OF HIV INFECTION STUDY GROUP

Among opportunistic pathogens associated with the acquired immunodeficiency syndrome (AIDS), Mycobacterium tuberculosis is distinguished by its relative virulence and potential for person-to-person transmission. Persons infected with human immunodeficiency virus (HIV) are particularly susceptible to tuberculosis, both from the reactivation of latent infection and from new infection with rapid progression to active disease [1-4]. The annual incidence of tuberculosis in the United States was 8.7 per 100 000 persons in 1995 [5], but rates 1000-fold higher have been reported in some HIV-seropositive populations [6-14]. Most studies have been restricted by geography, HIV-risk group, or specific high-prevalence settings; such restrictions have resulted in an inaccurate assessment of the overall effect of the HIV epidemic on the incidence of tuberculosis in the United States [15, 16]. The Pulmonary Complications of HIV Infection Study (PCHIS) [17] prospectively followed HIV-seropositive patients who had demographic variables similar to those of patients with AIDS in the United States. Participants with asymptomatic or symptomatic HIV infection were recruited from sites in the eastern, midwestern, and western United States. A previous report on this cohort [18] identified determinants of delayed-type hypersensitivity response and risk factors for tuberculin reactivity. We examined the incidence of tuberculosis among patients enrolled in the PCHIS for a median observation period of approximately 4.5 years. Methods Patients and Study Design The PCHIS was a multicenter, prospective study of the frequency and spectrum of pulmonary disorders in persons infected with HIV. From November 1988 through February 1990, 1171 HIV-seropositive persons and 182 HIV-seronegative persons were enrolled at centers in six U.S. cities: New York; Newark, New Jersey; Detroit; Chicago; San Francisco; and Los Angeles. Participants were followed through 31 March 1994. We report on 1130 HIV-infected persons from the PCHIS who were followed past baseline. Participants were recruited to represent a range of severity of HIV disease. Approximately half of the participants at each center had CD4 lymphocyte counts of 400 cells/mm3 or more and no HIV-related symptoms, and half had CD4 lymphocyte counts of less than 400 cells/mm3 or symptomatic HIV infection. Both groups included persons from one of three HIV-transmission categories: homosexual men, male and female injection drug users, and women who had acquired HIV through heterosexual contact. Exclusion criteria were AIDS, as defined by the Centers for Disease Control and Prevention (CDC) [19]; acute pulmonary processes; use of immunosuppressive therapy in the past 6 months; and treatment of tuberculosis in the past 12 months. The study was approved by the institutional review board at each site, and participants gave informed consent. At baseline and at regular intervals, clinical monitoring (including T-lymphocyte subset analysis and chest roentgenography) was done, and participants were acutely evaluated if new pulmonary symptoms occurred. Centers used the same predetermined diagnostic algorithms that were initiated if specified criteria were met. Complete details of the study design have been described elsewhere [17]. Delayed hypersensitivity was tested at baseline and then annually using purified protein derivative (PPD) tuberculin at a strength of 5 TU per 0.1-mL dose and mumps antigen (Connaught Laboratories, Inc., Swiftwater, Pennsylvania). Tests were administered by intradermal injection of 0.1 mL of antigen by the Mantoux method and read by experienced nurses 48 to 72 hours later in most cases (the interval exceeded 4 days in 18 persons). A positive response to PPD was defined as an induration at least 5 mm in diameter. Any person who was not positive when first tested but who became positive on any subsequent test was considered to be a tuberculin converter. A positive response to mumps was defined as any degree of induration (>0 mm). The criteria for anergy was nonreactivity (0 mm) to both PPD and mumps antigen. Pulmonary tuberculosis was defined by the isolation of M. tuberculosis from a respiratory tract specimen or by improvement on chest radiography in response to specific multidrug antituberculous therapy. Patients who were diagnosed with extrapulmonary tuberculosis had clinically compatible disease and response to specific therapy, with or without the isolation of the organism from a site outside the lung. Patients who were considered to have both pulmonary and extrapulmonary tuberculosis met each set of criteria. These requirements are consistent with those of the CDC for reporting cases of tuberculosis [20], except that we did not require patients to be PPD positive if they had disease that was not mycobacteriologically confirmed. Statistical Analysis Tuberculosis rates were calculated as the number of cases divided by the number of years that patients were followed multiplied by 100. Except as noted below, the length of time that patients were followed was calculated for each person starting from enrollment and continuing until one of the following occurred: diagnosis of tuberculosis, death from any cause, the last study visit, or 31 March 1994. Statistical significance for comparison of rates was determined by tests for person-time data done on the basis of binomial distribution [21]. P values were determined by an exact test when sample sizes were insufficient and by an asymptotic test when sizes were sufficient. All tests were two-sided, and a P value of 0.05 was considered significant. Exact 95% CIs were calculated for rates by assuming the numerator to be a Poisson variable [22] and for rate ratios using a modified binomial model [21]. Adjusted rate ratios for comparisons among groups defined by demographic variables were calculated by using a Mantel-Haenszel type estimator for incidence-rate data with approximate 95% confidence limits based on the tests [21]. Seventy-three participants, including women who had acquired HIV through heterosexual contact and persons were not black, white, or Hispanic, were excluded from some calculations of adjusted rates because of small sample sizes. Distributions of time to death among patients with tuberculosis were estimated using the Kaplan-Meier method, and comparisons were made using the log-rank test. To calculate tuberculosis rates by immunologic status, we divided the time each participant was followed into the number of years during which CD4 lymphocyte counts were 200 cells/mm3 or greater and the number of years after CD4 lymphocyte counts were less than 200 cells/mm3. Time for these CD4 groups was then summed for all participants. Rates were calculated as the number of tuberculosis cases in each group divided by the number of years followed. One participant who did not have CD4 measurements was omitted from these calculations. Twenty-three participants who were never tested for PPD response were excluded from PPD conversion rates and calculations of tuberculosis rates by PPD status. Participants who were tested for PPD response at least once were classified into one of three groups: positive at entry, newly positive (converted), or negative. One hundred seventy-two of 1107 participants were assigned to groups on the basis of only one test. Baseline PPD status was assigned for 66 participants who were not tested at study entry by using the first reported test and time followed calculated from the date of that test. For participants who developed tuberculosis, only the results of PPD tests done before diagnosis were considered. Tuberculin converters were considered to be part of the negative group before becoming PPD positive and to be part of the newly positive group after converting. Persons who reported a history of isoniazid use or tuberculosis before the study or who received isoniazid for at least 6 months during follow-up were considered to have completed prophylactic therapy. All others were considered to have not been given prophylaxis. Time before completion of isoniazid therapy was included with time followed in the untreated group. Restricted tuberculosis rates were calculated by PPD status for those considered to have not received prophylaxis. Results Patient Characteristics at Baseline Overall, 1171 HIV-seropositive persons entered the study. Follow-up was completed for 1130 persons (96%), whose baseline characteristics are shown in Table 1. Approximately 1% of patients reported a history of tuberculosis, 8% reported a previous positive result on a PPD test, and 4% reported previous use of isoniazid. The median CD4 T-lymphocyte count among HIV-seropositive patients was 410 cells/mm3: Thirty-six percent of patients had counts of at least 500 cells/mm3, 44% had counts between 200 and 499 cells/mm3, and 19% had counts of less than 200 cells/mm3. At study entry, 6% of patients were PPD positive, 42% were reactive to mumps antigen, and 54% were anergic. A cross-sectional analysis of skin-test results at baseline in this cohort has been described in detail elsewhere [18]. Table 1. Baseline Characteristics of the Study Chart* Patient Follow-up The median duration of follow-up was 53 months. By the end of the study, 655 persons had survived after a median follow-up of 57 months (range, 31 to 64 months), 354 had died after a median follow-up of 31 months (range, 1 to 63 months), and 121 withdrew or were lost to follow-up after a median of 25 months (range, 1 to 61 months). Participants received PPD skin tests a median of three times, and 1107 (98%) participants were evaluated at least once. Sixty-six (6%) participants were PPD positive when first tested. Among the 1041 patients who were PPD negative at first testing, 29 subsequently became PPD positive (0.8 conversions per 100 person-years). During follow-up, isoniazid prophylaxis was prescribed for 110 persons (10%), but only 53 (5%) received therapy for 6 months or more. Inc

Tuberculin and Anergy Testing in HIV-Seropositive and HIV-Seronegative Persons

Human immunodeficiency virus (HIV) is playing a substantial role in the resurgence of tuberculosis in the United States. Particularly affected are people in urban areas, where there are large populations of HIV-infected persons [1-8]. Urban subpopulations with a high prevalence of HIV infection, such as intravenous drug users (a group already at increased risk for tuberculosis before the appearance of the acquired immunodeficiency syndrome [AIDS]), have the highest tuberculosis attack rates [3]. Unlike other AIDS-associated opportunistic pathogens, Mycobacterium tuberculosis is readily communicable among persons with all levels of immunity. Recently, tuberculosis outbreaks, some with multidrug-resistant strains, have occurred among HIV-positive patients with transmission to HIV-negative patients and health care workers [9-13]. Prevention strategies rely heavily on the use of tuberculin purified protein derivative (PPD) to identify persons harboring M. tuberculosis [14]. Anergy, a consequence of HIV infection, undermines these strategies in persons at the highest risk for tuberculosis infection and subsequent active disease [15-18]. A negative PPD test result in this setting could be attributable to a true lack of exposure to tuberculosis or simply to the incapacity of the patient to manifest an appropriate cell-mediated immune response. To reduce the measured prevalence of anergy and thereby increase the proportion of tuberculin nonreactors who can be considered truly PPD negative, the Centers for Disease Control and Prevention (CDC) has recommended the additional use of at least two delayed-type hypersensitivity control antigens (mumps antigen plus Candida antigen or tetanus toxoid) when screening HIV-infected patients. Thus, persons from populations with a prevalence of tuberculous infection of 10% or more and who are tuberculin negative but not anergic may be spared preventive therapy with isoniazid [19]. However, the ability of control antigens to predict the likelihood that a negative PPD test result is truly negative in this highly anergic population is unknown. To improve approaches to tuberculosis prophylaxis, more data are needed about the relations among delayed-type hypersensitivity responsiveness, the prevalence of tuberculosis, and the waning immunity associated with progressive HIV infection. In an ongoing multicenter study of the natural history of the pulmonary complications associated with HIV infection, we have been examining these factors prospectively in a cohort of 1353 persons in 6 U.S. geographic areas. Recently, we evaluated baseline delayed-type hypersensitivity responses in this cohort of HIV-seropositive and HIV-seronegative persons and identified variables associated with tuberculin reactivity and anergy. Methods Patients and Study Design The Pulmonary Complications of HIV Infection Study is a multicenter study designed to prospectively describe the frequency, types, and effect of pulmonary complications in HIV-infected persons, both before and after the development of AIDS. All diagnoses, treatments, and outcomes are recorded and monitored in a common database. Because our purpose was to evaluate longitudinally both the early and late pulmonary manifestations of HIV infection, each center attempted to recruit about 170 HIV-seropositive participants, half with CD4 lymphocyte counts of 400 cells/mm3 or more and no HIV-related symptoms and half with fewer than 400 CD4 cells/mm3 or symptomatic HIV-infection (defined by a temperature of 38 C or more for at least 2 weeks, involuntary weight loss of 10% or more from baseline, diarrhea of at least a 1-month duration, oral candidiasis, or oral hairy leukoplakia). Within each group, participants were drawn from one of three HIV transmission categories (homosexual men, male and female intravenous drug users, and women with heterosexually acquired HIV infection) to reflect their approximate distribution at each clinical site. About 30 HIV-seronegative homosexual men and intravenous drug users were also recruited at each site to serve as controls. Participants had to be willing and able to comply with the protocol and were required to give informed consent. The study was reviewed and approved by the institutional review board at each site. Exclusion criteria included Centers for Disease Control and Prevention (CDC)-defined AIDS [20], severe non-HIV-related disease likely to affect survival, lung disorders likely to interfere with the required evaluations, acute pulmonary processes, immunosuppressive therapies within the previous 6 months, and treatment for active tuberculosis within the past 12 months. From November 1988 through February 1990, we enrolled 1353 persons in the study, of whom 1171 were HIV seropositive and 182 were HIV seronegative. Human immunodeficiency virus serologic status was confirmed at study entry using a licensed enzyme-linked immunosorbent assay and a Western blot assay. Further baseline evaluation included a complete medical history, a physical examination, hematologic and biochemical studies, T-lymphocyte subset analysis, delayed-type hypersensitivity testing, a chest roentgenogram, and pulmonary function measurements. Measurement of Delayed-Type Hypersensitivity Response We tested delayed-type hypersensitivity with the following antigens: mumps antigen (Connaught Laboratories, Inc., Swiftwater, Pennsylvania); Dermatophytin 0 (Candida) at 1:100 dilution (Hollister-Stier, Spokane, Washington); Dermatophytin (trichophytin) at 1:100 dilution (Hollister-Stier); and tuberculin PPD at a strength of 5 tuberculin units per 0.1-mL dose (Connaught Laboratories, Ltd., Willowdale, Ontario, Canada). Tests were administered by intradermal injection of 0.1 mL of antigen (Mantoux method) and read by a trained observer 48 to 72 hours after application in most participants (the interval exceeded 4 days in 18 persons). Response was recorded as the greatest diameter of induration. We used the current standard operational criteria for a positive response: induration of at least 5 mm for all antigens except PPD, for which an induration of 10 mm was required among HIV-uninfected persons [19]. Anergy was defined as 0 mm of induration for all delayed-type hypersensitivity antigens administered in a given panel. Unless otherwise specified, a test battery of tuberculin PPD, mumps antigen, and Candida antigen was used to define anergy. At one site, however, the investigators did not distinguish between induration and erythema for the mumps, Candida, and trichophytin tests, documenting reactions to these antigens in terms of millimeters of erythema. When examined by zone diameter, their measurements were generally consistent with those from the other centers. Furthermore, the results of multivariate analyses with and without the data from this site were similar. Other investigators have shown a high degree of correlation between induration and erythema with these antigens [21]. Thus, for the purposes of our analysis, responses were recorded in millimeters of induration. Because trichophytin elicited a positive reaction in only 14.0% of those tested, it was dropped from the delayed-type hypersensitivity battery midway through the enrollment period. Although lot numbers varied, the skin tests used at the centers were supplied by the same manufacturers, with a single exception: At one site, investigators used a different Candida preparation. The Candida test results for this center (247 participants) were excluded from all analyses involving this antigen. Determination of Lymphocyte Subsets Lymphocyte subsets were determined for CD3, CD4, and CD8 receptor-bearing cells by the same laboratory at each site. All laboratories participated in the flow cytometry quality control program sponsored by the National Institute of Allergy and Infectious Diseases [22]. Statistical Analysis All analyses are based on data collected during the baseline evaluation. Statistical significance for comparisons of proportions was determined by chi-square or Fisher exact test [23]. For comparisons among nonindependent groups, repeated-measures analysis for categorical outcomes was used to determine statistical significance [24, 25]. Logistic regression models were used to study the relation between PPD positivity or anergy and potential risk factors [26]. Risk factors considered were HIV status; CD4 count among HIV-seropositive persons; intravenous drug use; race or ethnicity; a history of a positive PPD test result, tuberculosis, or BCG vaccination; age; gender; and socioeconomic status. Seventy-seven participants, including women with heterosexually acquired infection and persons who were not white, black, or Hispanic, were excluded from all multivariate analyses because of small sample sizes. Initial models included HIV status (positive or negative), intravenous drug use (presence or absence), race or ethnicity (white, black, or Hispanic), a history of a positive PPD test result, and age, as well as interaction terms, to determine whether the effect of HIV positivity varied among these groups or whether the effect of drug use varied by race. No statistically significant interactions were observed. All odds ratios presented were derived from subsequent models containing main effects only. A dichotomous variable indicating the 12% of the cohort who did not have a high school diploma was used as an index of socioeconomic status and was included in all final models. All tests were two sided. A P value of 0.05 was considered statistically significant. Ninety-five percent CIs are given when appropriate. Results Patient Characteristics During the 16-month enrollment period, 1171 HIV-seropositive and 182 HIV-seronegative persons entered the study. The two groups were similar with regard to age, sex, race, transmission category, and tuberculosis-associated history (Table 1). Of the 1165 men, 966 (82.9%) were homosexual; of the 188 women, 132 (70.2%) were intravenous drug users.

Effect of Persistent Moderate Viremia on Disease Progression During HIV Therapy

ObjectiveAlthough highly active antiretroviral therapy has been shown to lower plasma HIV-1 RNA in HIV infection, many patients do not reach the target goal of undetectable viremia. We evaluated whether risk of clinical progression varies by level of viral suppression achieved. DesignPatients in the Collaborations in HIV Outcomes Research/United States cohort who maintained stable HIV-1 RNA levels of either <400, 400 to 20,000, or >20,000 copies/mL during a run-in period of at least 6 months were studied. Baseline was the first day after this period. MethodsProportional hazards models were used to quantify the relation between baseline HIV-1 RNA levels and risk of a new AIDS-defining diagnosis or death after adjusting for CD4 count, age, gender, ethnicity, study site, prior AIDS-defining diagnosis, and antiretroviral therapy history. ResultsPatients (N = 3010) were followed for up to 4.3 years after the 6-month run-in period, with 343 deaths or AIDS-defining diagnoses reported. The risk of a new AIDS-defining diagnosis or death was not significantly different in the 400 to 20,000– and <400-copies/mL groups (6% vs. 7%, hazard ratio [HR] = 1.0, 95% confidence interval [CI]: 0.7–1.4; P = 0.9) but was significantly higher in the >20,000-copies/mL group (26%, HR = 3.3, 95% CI: 2.5–4.4; P < 0.001 vs. the <400-copies/mL group). Median CD4 count changes during the first year of follow-up showed increases of 75 and 13 cells/mm3 for the <400- and 400 to 20,000–copies/mL groups, respectively, whereas the >20,000-copies/mL group had a decrease of 23 cells/mm3. ConclusionsPatients who maintained baseline HIV-1 RNA levels of 400 to 20,000 copies/mL for at least 6 months preserved immunologic status and were no more likely to die or develop a new AIDS-defining diagnosis in the time frame studied than those with baseline levels <400 copies/mL. Patients with HIV-1 RNA levels >20,000 copies/mL at baseline had greater clinical and immunologic deterioration. These data suggest that maintenance of moderate viremia may confer clinical benefit not seen when viremia exceeds 20,000 copies/mL, and this should be taken into account when considering the risks and benefits of continuing failing therapy.

Long-term colonization of a Lactobacillus plantarum synbiotic preparation in the neonatal gut.

Background: Probiotic, prebiotic, and synbiotic (a combination of pro- and prebiotic) supplements increasingly are being used to prevent and treat a variety of health conditions. Although colonization is considered a key element in the success of such treatments, few clinical studies have addressed colonizing ability. Studies are even more limited in neonates and infants, who may benefit most from such treatment. The present study was conducted to determine the colonizing ability, tolerance, and impact on the stool flora of 7 days of administration of a synbiotic supplement to a neonatal cohort, in preparation for a larger hospital-based trial. Patients and Methods: In this randomized, double-masked, controlled trial, healthy inborn newborns >35 weeks of gestational age and >1800 g birth weight were randomized between 1 and 3 days after birth to receive an oral synbiotic preparation (Lactobacillus plantarum and fructooligosaccharides) or a dextrose saline placebo. Two babies were treated with the synbiotic preparation for every 1 baby treated with the placebo. Duration of therapy was 7 days. Comprehensive stool cultures were done at baseline and on days 3, 7, 14, 21, and 28. Results: Nineteen infants received the active study supplement and 12 infants received the placebo for 7 days. L plantarum was cultured from the stools of 84% of the treated infants after 3 days of treatment, and from 95% of infants on day 28 after birth. Of the infants, 100%, 94%, 88%, 56%, and 32% remained colonized at months 2, 3, 4, 5, and 6, respectively. In both groups, the total mean number of species and the mean log colony counts increased over time. The number of bacterial species was significantly higher on days 21 and 28 in the synbiotic preparation group compared with placebo (P = 0.002 and 0.03, respectively). There was a linear increase in the mean log gram-negative colony counts in the placebo group during the 4-week period that was significantly higher than that in the Lactobacillus group on days 14, 21, and 28 (P < 0.001 for each). In contrast, the supplement group had significantly higher gram-positive colony counts on days 14 (P = 0.002) and 28 (P = 0.04). Only 1 infant in the placebo group was colonized with L fermentum during the first 28 days of life. No difference was found in the percent increase in weight between baseline and day 7, but on day 28 and months 2, 3, and 6, the percent increase from baseline was higher in the probiotic-treated group (P ≤ 0.05). The supplement was tolerated well. Conclusions: The synbiotic preparation colonized quickly after 3 days of administration and the infants stayed colonized for several months after therapy was stopped. There was an increase in bacterial diversity and gram-positive organisms and a reduction of gram-negative bacterial load in the treatment group. Because a combination preparation was used, it is difficult to specifically attribute the colonization to either the probiotic or prebiotic component in this study. Larger efficacy trials are warranted to examine the mechanism of action and precise effects of these supplements.