Pharmacokinetics and safety of coformulated bictegravir, emtricitabine, and tenofovir alafenamide in children aged 2 years and older with virologically suppressed HIV: a phase 2/3, open-label, single-arm study.

BACKGROUND: Coformulated bictegravir, emtricitabine, and tenofovir alafenamide is a single-tablet regimen and was efficacious and well tolerated in children and adolescents with HIV (aged 6 years to <18 years) in a 48-week phase 2/3 trial. In this study, we report data from children aged at least 2 years and weighing 14 kg to less than 25 kg. METHODS: We conducted this open-label, multicentre, multicohort, single-arm study in South Africa, Thailand, Uganda, and the USA. Participants were virologically suppressed children with HIV, aged at least 2 years, weighing 14 kg to less than 25 kg. Participants received bictegravir (30 mg), emtricitabine (120 mg), and tenofovir alafenamide (15 mg) once daily, switching to bictegravir (50 mg), emtricitabine (200 mg), and tenofovir alafenamide (25 mg) upon attaining a bodyweight of at least 25 kg. The study included pharmacokinetic evaluation at week 2 to confirm the dose of coformulated bictegravir, emtricitabine, and tenofovir alafenamide for this weight band by comparing with previous adult data. Primary outcomes were bictegravir area under the curve over the dosing interval (AUCtau) and concentration at the end of the dosing interval (Ctau) at week 2, and incidence of treatment-emergent adverse events and laboratory abnormalities until the end of week 24 in all participants who received at least one dose of bictegravir, emtricitabine, and tenofovir alafenamide. This study is registered with ClinicalTrials.gov, NCT02881320. FINDINGS: Overall, 22 participants were screened (from Nov 14, 2018, to Jan 11, 2020), completed treatment with bictegravir, emtricitabine, and tenofovir alafenamide (until week 48), and entered an extension phase. The geometric least squares mean (GLSM) ratio for AUCtau for bictegravir was 7·6% higher than adults (GLSM ratio 107·6%, 90% CI 96·7-119·7); Ctau was 34·6% lower than adults (65·4%, 49·1-87·2). Both parameters were within the target exposure range previously found in adults, children, or both". Grade 3-4 laboratory abnormalities occurred in four (18%) participants by the end week 24 and six (27%) by the end of week 48. Drug-related adverse events occurred in three participants (14%) by the end of week 24 and week 48; none were severe. No Grade 3-4 adverse events, serious adverse events, or adverse events leading to discontinuation occurred by the end of week 24 and week 48. INTERPRETATION: Data support the use of single-tablet coformulated bictegravir (30 mg), emtricitabine (120 mg), and tenofovir alafenamide (15 mg) for treatment of HIV in children aged at least 2 years and weighing 14 kg to less than 25 kg. FUNDING: Gilead Sciences.

Risk of COVID-19 after natural infection or vaccination.

BACKGROUND: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. METHODS: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7-15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. FINDINGS: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05-0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01-0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. INTERPRETATION: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. FUNDING: National Institutes of Health.

Novel Application of Dot Survey Methodology at a Youth Health Clinic: A Pilot Study.

PURPOSE: We tested a novel dot survey methodology at our clinic that provides sexual health services to youth ages 13 to 24. We conducted two interactive dot surveys to assess their feasibility and acceptability while gaining insight into patients' attitudes about mental health. METHODS: We adapted a dot survey approach to assess youths' familiarity with mental health and attitudes toward related services. We also assessed their attitudes toward participating in this survey method. All patients with scheduled appointments were eligible to participate. Participants used dot stickers to indicate their responses on survey posters displayed in the waiting room. RESULTS: Three hundred patients participated between June and September 2021 (150 participants/survey). About 95% of participants liked seeing others' responses to the dot surveys, and over 70% reported that the surveys made them think more about mental health. Over 90% would participate in future dot surveys at the clinic. Survey items with the most consensus among participants included that 74.5% "really agree" youth face barriers to accessing mental health services (n = 141, mean = 4.61, standard deviation = 0.79) and 87.1% "really agree" primary care providers should ask youth about their mental health (n = 139, mean = 4.81, standard deviation = 0.59). DISCUSSION: The dot surveys were effective at assessing patients' attitudes about mental health and feasible to conduct in our waiting room. Results confirmed that this survey method was well received among patients. Dot surveys can be adapted by other clinical settings to engage youth regarding their health-related attitudes.

Assessing the Attitude of Tampa Bay Youth toward HIV Self-Testing Kits.

In adults, data support the utility and acceptance of home HIV testing; however, in youth, particularly in the US, this has not been well studied. In this exploratory study, we surveyed Tampa Bay youth aged 16-27 and attending sexual health clinics between 1 June and 31 June 2018 (n = 133) regarding attitudes and perceptions towards HIV self-testing. While most indicated the clinic over home when asked for preferred testing location, study population and subgroup analysis demonstrated a positive response (agree) to Likert-scale questions regarding the use of home HIV self-testing kits and negative responses (strongly disagree) to "would not use self-testing kit". There was a significant difference between genders in testing location preference (p = 0.031) for those respondents that specified gender (n = 123), with males more likely to prefer home testing than females. This study suggests an openness of youth towards HIV home testing that could help to expand the number of youth aware of their HIV status.

Fixed-dose combination bictegravir, emtricitabine, and tenofovir alafenamide in adolescents and children with HIV: week 48 results of a single-arm, open-label, multicentre, phase 2/3 trial.

BACKGROUND: Bictegravir is a potent integrase strand-transfer inhibitor (INSTI) with a high genetic barrier to resistance. Bictegravir, coformulated with emtricitabine and tenofovir alafenamide, is recommended by key European and US HIV treatment guidelines as the preferred single-tablet regimen for adults and adolescents. The aim of this study was to assess the pharmacokinetics, safety, and efficacy of switching to this regimen in virologically suppressed children and adolescents with HIV. METHODS: In this single-arm, open-label trial, we enrolled virologically suppressed children and adolescents (aged 6 to <18 years) with HIV at 22 hospital clinics in South Africa, Thailand, Uganda, and the USA. Eligible participants had a bodyweight of at least 25 kg, were virologically suppressed (HIV-1 RNA <50 copies per mL) on a stable ART regimen for at least 6 months before screening, had a CD4 count of at least 200 cells per µL, and an estimated glomerular filtration rate of at least 90 mL/min per 1·73 m2 by the Schwartz formula at screening. All participants received the fixed-dose regimen of coformulated bictegravir 50 mg, emtricitabine 200 mg, and tenofovir alafenamide 25 mg once daily. Pharmacokinetic analysis was used for dosing confirmation, and results compared with adult values. The primary outcomes were area under the curve at the end of the dosing interval (AUCtau) and concentration at the end of the dosing interval (Ctau) of bictegravir, and incidence of treatment-emergent adverse events and laboratory abnormalities at week 24. Efficacy and safety analyses included all participants who received at least one dose of study drug. We report the 48-week results. This study is registered with ClinicalTrials.gov, NCT02881320. FINDINGS: Between Sept 29, 2016 and Feb 16, 2018, we enrolled 102 participants. 100 participants received bictegravir, emtricitabine, and tenofovir alafenamide (cohort 1 [adolescents aged 12 to <18 years], n=50; cohort 2 [children aged 6 to <12 years], n=50). The mean bictegravir AUCtau was 89 100 ng × h/mL (coefficient of variation 31·0%) in adolescents (cohort 1) and 128 000 ng × h/mL (27·8%) in children (cohort 2). Compared with adults, bictegravir Ctau was 35% lower in adolescents and 11% lower in children. The 90% CIs of both parameters were within the predefined pharmacokinetic equivalence boundary and within overall range of exposures observed in adults and deemed to be safe and efficacious (geometric least-squares mean ratio [GLSM] 86·3% [90% CI 80·0-93·0] for AUCtau and 65·4% [58·3-73·3] for Ctau in adolescents; GLSM 125% [90% CI 117-134] for AUCtau and 88·9% [80·6-98·0] for Ctau for children). Bictegravir, emtricitabine, and tenofovir alafenamide was well tolerated; most adverse events were grade 2 or less in severity and no study drug-related serious adverse events were reported. One participant discontinued study drug due to adverse events (grade 2 insomnia and anxiety). Virological suppression (HIV-1 RNA <50 copies per mL) was maintained by all 100 participants at week 24 and by 98 (98%) of 100 at week 48; no participants had treatment-emergent resistance. INTERPRETATION: In adolescents and children with HIV, the bictegravir, emtricitabine, and tenofovir alafenamide single-tablet regimen was well tolerated and maintained virological suppression. Our data support the treatment of HIV in adolescents and children with this single-tablet regimen. At present, the single-tablet regimen is recommended as first-line treatment in the USA for adolescents and as an alternative regimen in children and has the potential to represent an important regimen in the paediatric population. FUNDING: Gilead Sciences.

Health Knowledge and Adherence as Predictors of Viral Burden and CD4+ T-Cell Count in Youth and Young Adults Living With HIV.

Health literacy influences HIV treatment for youth and, thus, is a research priority. We explored health knowledge and self-reported adherence, as indicators of health literacy, among youth living with HIV (YLWH) and the association between health literacy and health outcomes. A total of 102 YLWH ages 13-25 years participated in the study. Participants completed the Brief Estimate of Health Knowledge and Action-HIV Version; CD4 T-cell counts and viral loads were extracted from participant medical records. Participants had a moderate amount of HIV knowledge, and most reported taking their medications under most conditions. Decreasing action scores were statistically associated with an increased likelihood of having a detectable viral load. Health literacy is an important factor that should be addressed by practitioners working with YLWH. More research is needed to determine the best way to measure and improve health literacy.

Depression, anxiety, and posttraumatic stress as predictors of immune functioning: differences between youth with behaviorally and perinatally acquired HIV.

Youth living with HIV (YLWH) face significant mental health problems, namely depression, anxiety, and PTSD with rates of these disorders higher than in the general population. This study explored the relationship between symptoms of depression, anxiety, and PTSD and biological markers among a sample of 145 YLWH ages 13-25 years. Participants completed the Center for Epidemiologic Studies Depression Scale (CES-D), Generalized Anxiety Disorder-7 Item Scale (GAD-7), and Primary Care-Posttraumatic Stress Disorder Screen (PC-PTSD). Biological markers included CD4 count and viral load (VL) abstracted from medical records. Findings revealed a relationship between depression and anxiety and CD4 count as well as anxiety and VL. The relationship between depression and anxiety and CD4 count and anxiety and VL was moderated by transmission mode (i.e., behavioral versus perinatal). For youth perinatally infected, greater psychological symptoms of depression and anxiety were associated with a decline in CD4 count and increase in VL, but this was not true for youth with behaviorally acquired HIV. These findings point to the need for individualized mental health prevention and intervention services for YLWH.

Accurate PCR Detection of Influenza A/B and Respiratory Syncytial Viruses by Use of Cepheid Xpert Flu+RSV Xpress Assay in Point-of-Care Settings: Comparison to Prodesse ProFlu.

The Xpert Flu+RSV Xpress Assay is a fast, automated in vitro diagnostic test for qualitative detection and differentiation of influenza A and B viruses and respiratory syncytial virus (RSV) performed on the Cepheid GeneXpert Xpress System. The objective of this study was to establish performance characteristics of the Xpert Flu+RSV Xpress Assay compared to those of the Prodesse ProFlu+ real-time reverse transcription-PCR (RT-PCR) assay (ProFlu+) for the detection of influenza A and B viruses as well as RSV in a Clinical Laboratory Improvement Amendments (CLIA)-waived (CW) setting. Overall, the assay, using fresh and frozen nasopharyngeal (NP) swabs, demonstrated high concordance with results of the ProFlu+ assay in the combined CW and non-CW settings with positive percent agreements (PPA) (100%, 100%, and 97.1%) and negative percent agreements (NPA) (95.2%, 99.5%, and 99.6%) for influenza A and B viruses and RSV, respectively. In conclusion, this multicenter study using the Cepheid Xpert Flu+RSV Xpress Assay demonstrated high sensitivities and specificities for influenza A and B viruses and RSV in ∼60 min for use at the point-of-care in the CW setting.

Screening for depression among youth with HIV in an integrated care setting.

Youth living with HIV (YLWH) are at risk for depression. Depressive symptoms can impact treatment engagement, health outcomes, and quality of life. Early identification of symptoms can guide treatment planning. This study aimed to identify trends in depressive symptoms for YLWH in a specialty-care clinic and follow-up clinical treatment procedures. An archival review of a clinical database provided depression screening information for a sample of 130 YLWH between 11 and 25 years old in the southeastern United States. Findings indicated that approximately 24% of the sample screened positive for depression-risk. Most commonly endorsed symptoms included fatigue (54.3%) and sleep difficulties (48.5%). Depressive symptoms did not differ significantly by age, gender, race, ethnicity, or sexual orientation. Youth who acquired HIV behaviorally were more likely to endorse the critical item (i.e., self-harm and/or suicidal ideation) than youth who acquired HIV perinatally. Forty-percent of the sample (i.e., 51 youth) had a follow-up treatment plan. YLWH who endorsed the critical item were more likely to receive follow-up action when compared to those who did not endorse the item. Despite limitations of the study, findings have important implications for clinical care and future research.

Characterization of the pediatric acute-onset neuropsychiatric syndrome phenotype.

OBJECTIVE: Pediatric acute-onset neuropsychiatric syndrome (PANS) is a subtype of obsessive compulsive disorder (OCD) marked by an abrupt onset or exacerbation of neuropsychiatric symptoms. We aim to characterize the phenotypic presentation of youth with PANS. METHODS: Forty-three youth (ages 4-14 years) meeting criteria for PANS were assessed using self-report and clinician-administered measures, medical record reviews, comprehensive clinical evaluation, and laboratory measures. RESULTS: Youth with PANS presented with an early age of OCD onset (mean=7.84 years) and exhibited moderate to severe obsessive compulsive symptoms upon evaluation. All had comorbid anxiety and emotional lability, and scored well below normative means on all quality of life subscales. Youth with elevated streptococcal antibody titers trended toward having higher OCD severity, and presented more frequently with dilated pupils relative to youth without elevated titers. A cluster analysis of core PANS symptoms revealed three distinct symptom clusters that included core characteristic PANS symptoms, streptococcal-related symptoms, and cytokine-driven/physiological symptoms. Youth with PANS who had comorbid tics were more likely to exhibit a decline in school performance, visuomotor impairment, food restriction symptoms, and handwriting deterioration, and they reported lower quality of life relative to youth without tics. CONCLUSIONS: The sudden, acute onset of neuropsychiatric symptoms, high frequency of comorbidities (i.e., anxiety, behavioral regression, depression, and suicidality), and poor quality of life capture the PANS subgroup as suddenly and severely impaired youth. Identifying clinical characteristics of youth with PANS will allow clinicians to diagnose and treat this subtype of OCD with a more strategized and effective approach.

Microbial translocation induces persistent macrophage activation unrelated to HIV-1 levels or T-cell activation following therapy.

OBJECTIVE: HIV-1 replication and microbial translocation occur concomitant with systemic immune activation. This study delineates mechanisms of immune activation and CD4 T-cell decline in pediatric HIV-1 infection. DESIGN: Cross-sectional and longitudinal cellular and soluble plasma markers for inflammation were evaluated in 14 healthy and 33 perinatally HIV-1-infected pediatric study volunteers prior to and over 96 weeks of protease-inhibitor-containing combination antiretroviral therapy (ART). All HIV-1-infected patients reconstituted CD4 T cells either with suppression of viremia or rebound of drug-resistant virus. METHODS: Systemic immune activation was determined by polychromatic flow cytometry of blood lymphocytes and ELISA for plasma soluble CD27, soluble CD14, and tumor necrosis factor. Microbial translocation was evaluated by limulus amebocyte lysate assay to detect bacterial lipopolysaccharide (LPS) and ELISA for antiendotoxin core antigen immunoglobulin M (IgM) antibodies. Immune activation markers were compared with viral load, CD4 cell percentage, and LPS by regression models. Comparisons between healthy and HIV-1-infected or between different viral outcome groups were performed by nonparametric rank sum. RESULTS: Microbial translocation was detected in healthy infants but resolved with age (P < 0.05). LPS and soluble CD14 levels were elevated in all HIV-1-infected patients (P < 0.05 and P < 0.0001, respectively) and persisted even if CD4 T cells were fully reconstituted, virus optimally suppressed, and lymphocyte activation resolved by ART. Children with CD4 T-cell reconstitution but viral rebound following ART continued to display high levels of soluble CD27. CONCLUSION: Microbial translocation in pediatric HIV-1 infection is associated with persistent monocyte/macrophage activation independent of viral replication or T-cell activation.

Antiretroviral therapy corrects HIV-1-induced expansion of CD8+ CD45RA+ CD2-) CD11a(bright) activated T cells.

BACKGROUND: HIV infection decreases thymic output and induces chronic T-cell activation. OBJECTIVE: To examine the reconstitution of naive and activated T cells. METHODS: Extended immune phenotyping of CD4(+) and CD8(+) T-cell subsets was combined with T-cell receptor rearrangement excision circle (TREC) levels and measures of T-cell receptor repertoire perturbations in CD8(+) T-cell subpopulation to define the global effect of HIV-1 on T-cell dynamics. Evaluations before and after therapy were performed in HIV-infected children and compared with those in healthy individuals. RESULTS: Ten HIV-infected children and adolescents with a broad range of pretherapy CD4(+) T-cell counts were compared with healthy individuals. Pretherapy late activated CD8(+) T cells (CD3(+)CD8(+)CD45RA(+)CD27(-)CD11a(bright) cells) were expanded among HIV-infected subjects. Successful antiretroviral therapy increased the proportion of naive T cells (CD3(+)CD4(+)CD45RA(+)CD27(+)CD28(+) and CD3(+)CD8(+)CD45RA(+)CD27(+)CD11a(dim) cells), with a significant decrease in late activated CD8(+) T cells. The proportion of naive CD4(+) and CD8(+) T cells significantly predicted log(10) TREC copies/10(6) PBMCs in infected children and healthy control subjects, with a negative correlation in late activated CD8(+) T cells and activated CD4(+) T cells. Treatment re-established Gaussian distributions and decreased oligoclonal expansion within the Vbeta repertoire of CD8(+)CD45RA(+) T cells, but compared with that seen in healthy children, the proportion of late activated CD8(+) T cells remained increased. CONCLUSION: HIV infection strikingly shifts the proportion of naive and late activated CD45RA(+)CD8(+) T cells. Homeostasis within this T-cell population reflects TREC levels and the extent of T-cell receptor Vbeta perturbations.

Clinical implications of discordant viral and immune outcomes following protease inhibitor containing antiretroviral therapy for HIV-infected children.

Many HIV-infected children treated with protease inhibitors (PI) reconstitute immunity despite viral breakthrough predicting disease progression. We studied a unique cohort of PI treated children with advanced disease who demonstrated sustained CD4 T cell counts but median post therapy viral load rebounded to >4.0 log(10) copies/ml. Phylogenetic relationships between pre- and post-therapy viruses reveals significant bottlenecks for quasispecies with natural polymorphisms mapping outside of protease active site providing selective advantage for emergence. Among discordant subjects post-therapy viruses fell into two phenotypes; high viral loads (median >5.0 log(10) copies/ml) and attenuated post-therapy replication (median <4.0 log(10) copies/ml). Both groups showed similar degrees of CD4 T cell immune reconstitution and were similar to children who optimally suppressed virus to <400 copies/ml. Both high fit and low fit discordant response groups showed high reconstitution of naïve CD4 CD45RA T cells (median 388 and 357 cells/microl, respectively). Naïve T cells increases suggest virus replicating under PI selective pressure do not impair thymic output. If therapeutic options are limited, selection of therapy which allows immune reconstitution despite suboptimal viral control may be beneficial. This novel paradigm for virus/host interactions may lead to therapeutic approaches to attenuate viral pathogenesis.

Nontypeable Haemophilus influenzae adheres to intercellular adhesion molecule 1 (ICAM-1) on respiratory epithelial cells and upregulates ICAM-1 expression.

Nontypeable Haemophilus influenzae (NTHI) is an important respiratory pathogen. NTHI initiates infection by adhering to the airway epithelium. Here, we report that NTHI interacts with intracellular adhesion molecule 1 (ICAM-1) expressed by respiratory epithelial cells. A fourfold-higher number of NTHI bacteria adhered to Chinese hamster ovary (CHO) cells transfected with human ICAM-1 (CHO-ICAM-1) than to control CHO cells (P < or = 0.005). Blocking cell surface ICAM-1 with specific antibody reduced the adhesion of NTHI to A549 respiratory epithelial cells by 37% (P = 0.001) and to CHO-ICAM-1 cells by 69% (P = 0.005). Preincubating the bacteria with recombinant ICAM-1 reduced adhesion by 69% (P = 0.003). The adherence to CHO-ICAM-1 cells of NTHI strains deficient in the adhesins P5, P2, HMW1/2, and Hap or expressing a truncated lipooligosaccharide was compared to that of parental strains. Only strain 1128f-, which lacks the outer membrane protein (OMP) P5-homologous adhesin (P5 fimbriae), adhered less well than its parental strain. The numbers of NTHI cells adhering to CHO-ICAM-1 cells were reduced by 67% (P = 0.009) following preincubation with anti-P5 antisera. Furthermore, recombinant ICAM bound to an OMP preparation from strain 1128f+, which expresses P5, but not to that from its P5-deficient mutant, confirming a specific interaction between ICAM-1 and P5 fimbriae. Incubation of respiratory epithelial cells with NTHI increased ICAM-1 expression fourfold (P=0.001). Adhesion of NTHI to the respiratory epithelium, therefore, upregulates the expression of its own receptor. Blocking interactions between NTHI P5 fimbriae and ICAM-1 may reduce respiratory colonization by NTHI and limit the frequency and severity of NTHI infection.

Respiratory viruses augment the adhesion of bacterial pathogens to respiratory epithelium in a viral species- and cell type-dependent manner.

Secondary bacterial infections often complicate respiratory viral infections, but the mechanisms whereby viruses predispose to bacterial disease are not completely understood. We determined the effects of infection with respiratory syncytial virus (RSV), human parainfluenza virus 3 (HPIV-3), and influenza virus on the abilities of nontypeable Haemophilus influenzae and Streptococcus pneumoniae to adhere to respiratory epithelial cells and how these viruses alter the expression of known receptors for these bacteria. All viruses enhanced bacterial adhesion to primary and immortalized cell lines. RSV and HPIV-3 infection increased the expression of several known receptors for pathogenic bacteria by primary bronchial epithelial cells and A549 cells but not by primary small airway epithelial cells. Influenza virus infection did not alter receptor expression. Paramyxoviruses augmented bacterial adherence to primary bronchial epithelial cells and immortalized cell lines by up-regulating eukaryotic cell receptors for these pathogens, whereas this mechanism was less significant in primary small airway epithelial cells and in influenza virus infections. Respiratory viruses promote bacterial adhesion to respiratory epithelial cells, a process that may increase bacterial colonization and contribute to disease. These studies highlight the distinct responses of different cell types to viral infection and the need to consider this variation when interpreting studies of the interactions between respiratory cells and viral pathogens.

Pediatric HIV infection: diagnostic laboratory methods.

The diagnosis of HIV-1 infection in infants and children continues to present challenges. Currently available virologic assays are sensitive and specific and allow early detection of perinatally acquired HIV infection. Identification soon after birth allows for the rapid initiation of antiretroviral therapy and preservation of the infant's immune system. Serologic diagnostic methods, including HIV-ELISA, Western blot, and immunofluorescence Assay can be used to make the diagnosis of HIV infection in infants older than 18 months of age, children, and adolescents. Recently developed rapid tests allow for testing outside clinical sites, provide results in a short period of time, and allow for prompt initiation of effective prophylaxis in cases of exposure particularly maternal to child transmission. We discuss here the diagnostic management of HIV-exposed infants and HIV-infected children.

Pediatric HIV infection: immune and viral evaluation.

Advances in laboratory methods have driven improvements in the management and treatment of HIV infection. The methods to accurately and rapidly diagnose HIV infection in infants and children have been outlined in the previous article. In this review, the laboratory evaluation of infected children is described and methods to monitor progression of disease and response to therapy outlined.

Tolerance to vancomycin in pneumococci: detection with a molecular marker and assessment of clinical impact.

BACKGROUND: Vancomycin is often added to therapy for meningitis caused by Streptococcus pneumoniae. Tolerant bacteria without classic resistance that escape killing by multiple antibiotics have been reported sporadically. We determined the prevalence of tolerance to vancomycin in pneumococci and its effect on the outcome of meningitis. METHODS: Archival samples of 215 nasopharyngeal (NP) and 113 meningitis isolates were tested for the killing efficacy of vancomycin. Specific DNA sequence changes in a transporter locus were identified for tolerant isolates. Similar tests were conducted prospectively on 517 NP isolates from healthy children. RESULTS: In archival isolates, tolerance to vancomycin was detected in 3.7% of NP and 10.6% of invasive isolates. Patients with meningitis caused by tolerant isolates had a worse estimated 30-day survival than did patients with meningitis caused by nontolerant isolates (49% vs. 86%; P = .048); 62.5% of tolerant archival NP isolates harbored a specific sequence change for pep27 and vex2 (P = .021). Prospective analysis of 517 carriage isolates indicated that 8.1% were tolerant to vancomycin and that 82.1% of tolerant isolates harbored the specified marker gene sequences (P = .001). CONCLUSIONS: Tolerance to vancomycin exists in the population of pneumococci. Tolerant isolates are associated with meningitis of increased mortality, and these isolates can be tracked by specific marker sequences in 2 genes.

Pgi genotyping is a surrogate for serotyping of encapsulated Haemophilus influenzae.

Study of the epidemiology of invasive infections caused by encapsulated Haemophilus influenzae has been complicated by the poor sensitivity and specificity of the serologic assays used to identify specific capsular polysaccharides. The population structure of these bacteria is highly clonal, however, and serotype is highly correlated with other genetic characteristics. We sought to determine if alleles of the highly conserved phosphoglucose isomerase (pgi) gene correspond to the serotypes of encapsulated H. influenzae strains. pgi alleles of 52 well-characterized encapsulated H. influenzae isolates were amplified by PCR, sequenced, and compared to one another and to additional previously reported H. influenzae pgi alleles. Overall, 83% of the strains possessed pgi alleles associated with the major serotype a, b, e, and f clonotypes that cause the most invasive disease in the United States. Six strains (four type a and two type f) had unusual pgi alleles, which suggested that these strains belonged to less common clonotypes of encapsulated bacteria or were actually nontypeable strains. pgi genotyping may provide a simple and stable surrogate for capsular serotyping. Further studies correlating pgi typing with the expression of capsule are likely to increase our understanding of the epidemiology and pathogenesis of these infections.

Prevalence and distribution of adhesins in invasive non-type b encapsulated Haemophilus influenzae.

Adhesion to the respiratory epithelium plays an important role in Haemophilus influenzae infection. The distribution of H. influenzae adhesins in type b and nontypeable strains has been characterized, but little is known about the prevalence of these factors in non-type b encapsulated strains. We analyzed 53 invasive type a, type e, and type f strains for the presence of hap, hia, hmw, and hif genes; Hap, Hia, and HMW1/2 adhesins; and hemagglutinating pili. The hap gene was ubiquitous, and homologs of hmw and hia were present in 7 of 53 (13.2%) and 45 of 53 (84.9%) strains, respectively. Hap was detected in 28 of 45 (62.2%) hap(+) strains, HMW1/2 was detected in 5 of 7 (71.4%) hmw(+) strains, and Hia was detected in 31 of 45 (68.8%) hia(+) strains. The hif gene cluster was present in 26 of 53 strains (49.1%), and 21 of 26 hif(+) strains (80.8%) agglutinated (HA) red blood cells. Nine isolates exhibited HA but lacked the hif gene cluster. The distribution of adhesin genes correlated with the genetic relatedness of the strains. Strains belonging to one type a clonotype and the major type e clonotype possessed hia but lacked the hif cluster. Strains belonging to the second type a clonotype possessed both hia and hif genes. All type f strains belonging to the major type f clonotype possessed hia and lacked hifB. Although the specific complement of adhesin genes in non-type b encapsulated H. influenzae varies, most invasive strains express Hap and Hia, suggesting these adhesins may be especially important to the virulence of these organisms.