Opportunistic infections and other clinical manifestations of HIV disease in children

The Incidence of Respiratory Tract Infections in Vertically HIV-Infected Children in Lower Silesia in Poland and the Approach to Infection Prevention

Human immunodeficiency virus (HIV) is a risk factor associated with respiratory tract infections. However little is known about the prevalence of these infections in HIV-infected children in Poland. We investigated the incidence of respiratory tract infections in 26 HIV-infected children (aged 4-18, mean 10.3 years, including 17 girls) treated in our center and compared it with the age-matched control group of 70 children. The prevalence of chronic diseases and other factors such as cigarette smoking by household members or attending educational institutions were also taken into consideration. Among the HIV-infected children, 48 respiratory infections were observed, including 4 cases of pneumonia and 44 other respiratory infections for 312 person-month observations vs. 256 infections including 13 cases of pneumonia and 243 other respiratory infections for 840 person-month observations in the control group. Thus, incidence of respiratory infections per month was lower in HIV-infected children (14%) compared with the control group (29%), i.e., 0.14 95% CI (0.10-0.18) infections per month vs. 0.29 95% CI (0.26-0.32). There was no difference in the incidence of pneumonia. The lower incidence of respiratory infections in HIV-infected children may be explained by their avoiding sick people, taking influenza vaccination on the annual basis, and possibly antiviral medication. We conclude that the influence of modifiable environmental factors that reduce the risk of respiratory tract infections is more significant than the HIV infection itself.

Incidence of congenital toxoplasmosis among infants born to HIV-coinfected mothers: case series and literature review

INTRODUCTION

There is a paucity of data on the occurrence of congenital toxoplasmosis in children born to mothers dually infected with HIV and Toxoplasma gondii.

OBJECTIVE

To evaluate aspects of the mother-infant pairs associated with vertical transmission of toxoplasmosis in women co-infected with HIV in a referral center for perinatally acquired infections in Belo Horizonte, Brazil.

METHODS

Descriptive study of HIV vertically exposed children, with congenital toxoplasmosis, followed at a referral center (cohort/Belo Horizonte). Prenatal and post-natal variables for the mother-infant pairs were evaluated. A literature review with no filtering for time and language was performed to identify reports of congenital toxoplasmosis in HIV vertically exposed children.

RESULTS

Among 2007 HIV vertically exposed children evaluated in the period from 1998 to 2011, 10 cases of congenital toxoplasmosis were identified (incidence: 0.5%, 95% confidence interval: 0.24-0.91). In searching the literature 22 additional cases in 17 reports were found. Combining the findings of our cohort with other reported cases, 50% (16/32) of congenital toxoplasmosis in HIV vertically exposed children were from Brazil. The cases of congenital toxoplasmosis in HIV vertically exposed children identified in Brazil occurred mainly in the post-Highly Active Antiretroviral Therapy era (p=0.002) and presented a lower death rate (p=0.003) than those from other countries. In the cohort/Belo Horizonte, HIV infection was identified mainly during gestation; T. gondii vertical transmission was observed in pregnant women with CD4(+)>500 cells/mm(3) and latent toxoplasmosis. High rates of ocular lesions (87.5%) and central nervous system involvement (70%) were detected.

CONCLUSIONS

The risk of vertical transmission of T. gondii in HIV-infected women is low and has been usually associated with maternal immunosuppression and elevated viral load. However, our findings of congenital toxoplasmosis in children born to HIV-infected mothers with latent toxoplasmosis and not immunosuppressed emphasize the need for careful follow-up in these cases.

[Guidelines for the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). 2011 Update]

The guidelines on the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) are presented. These recommendations are focused on four clinical categories: oncology-haematology patients, solid organ transplant recipients, patients admitted to intensive care units, and children. An extensive review is made of therapeutical advances and scientific evidence in these settings. These guidelines have been prepared according the SEIMC consensus rules by a working group composed of specialists in infectious diseases, clinical microbiology, critical care medicine, paediatrics and oncology-haematology. Specific recommendations on the prevention of fungal infections in these patients are included.

Clinical profile of 516 children affected by HIV in a tertiary care centre in northern India: 14 years of experience

Increasing numbers of children affected by HIV are being recognised in northern India. The present study aimed to evaluate the clinical profile of 516 children affected by HIV at the Pediatric Allergy and Immunology Unit, Advanced Pediatric Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India, during the period January 1994 to May 2008. In total, 454 children (327 boys and 127 girls) infected by HIV were analysed. The median age at presentation was 54 months. Of these children, 401 (88.3%) acquired the infection vertically and 26 (5.7%) acquired it through transfusion of blood/blood products. Moreover, 156 children (34.4%) were asymptomatic at presentation to hospital. Common clinical features included fever (36.6%), respiratory infections (31.7%), lymphadenopathy (30.0%), hepatosplenomegaly (21.8%) and diarrhoea (18.1%); 299 children (65.9%) were malnourished. Triple drug antiretroviral therapy was initiated in 205 children. Children receiving such therapy showed significant improvement in clinical and immunological parameters. Furthermore, follow-up rates improved markedly following free supply of the drug. Therapy was very well tolerated. To conclude, physicians looking after children need to be familiar with the varying clinical presentation of HIV infection. To the best of our knowledge, this is the largest paediatric series on HIV infection from a single centre from any developing country.

Efficacy of Rifabutin-Loaded Microspheres for Treatment ofMycobacterium Avium-Infected Macrophages and Mice

Two poly(DL-lactide-co-glycolide) microsphere formulations (A, 10% wt/wt, and B, 23% wt/wt, 1-10 microns) were evaluated for intracellular delivery of rifabutin using the J774 murine and Mono Mac 6 (MM6) human monocytic cell lines. Within 7 days, formulation A released 100% in both cell lines and B released 53 and 67% in the J774 and MM6, respectively. Intracellular release of rifabutin with both formulations caused significant reduction of intracellularly replicating Mycobacterium avium (MAC). In MAC-infected beige mice, formulation B (50 mg, intraperitoneal days 0 and 7) completely eliminated infection by 21 days (p < 0.001), similar to a rifabutin daily oral regimen.

Clinical and microbiological characteristics of community-acquired pneumonia among human immunodeficiency virus-infected patients in northern Thailand

Human immunodeficiency virus (HIV) infections are prevalent in Thailand. However, the clinical and microbiological characteristics of community-acquired pneumonia (CAP) in such patients are not completely clear at present. In the present study, we analyzed the characteristics of CAP in 191 HIV-infected patients (192 episodes, 130 males and 61 females, mean age 32.9 years, range: 20-62) who had been admitted to Nakornping Hospital in northern Thailand between December 1996 and January 2002. The mean peripheral blood CD4 lymphocyte count was 68.5/mm3 (range: 0-791). The most common organisms detected in the blood of the subjects were as follows: Penicillium marneffei, 13, Salmonella spp., 5, Cryptococcus neoformans, 4, Staphylococcus aureus, 3, and Rhodococcus equi, 3, and the most common organisms detected in sputum included Haemophilus influenzae, 38, P. marneffei, 10, Streptococcus pneumoniae, 10, R. equi, 9, and S. aureus, 9. Life-threatening meningitis in 5 (cryptococcal in 3 and tuberculous in 2), pneumothorax in 2, and tuberculous lymphadenitis in 1 were also noted, resulting in 21 fatalities (10.9%). The mean peripheral blood CD4 lymphocyte count for cases in which the subject died was 74.8/mm3 (range: 0-340). Logistic regression analysis demonstrated that high age (odds ratio of over 40 years: 15.62) and R. equi infection (odds ratio: 8.14) are related to death of HIV-infected patients with CAP. The above findings indicate that various types of organisms, including mixed organisms, cause CAP in HIV-infected patients in northern Thailand, and high age and R. equi infection seem to be risk factors for death.

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.

Elevated mitogen-activated protein kinase signalling and increased macrophage activation in cells infected with a glycopeptidolipid-deficient Mycobacterium avium

Mycobacterium avium is a significant cause of morbidity and mortality in AIDS patients. M. avium can be isolated as three major morphotypes: smooth-transparent (SmT ), smooth-opaque (SmO) and rough (Rg). Studies indicate that many Rg isolates lack or have modified glycopeptidolipids (GPLs). GPLs are major surface constituents of the M. avium cell wall and heterogeneity in their carbohydrate moieties has been used to classify M. avium into different serotypes, with serotypes 1, 4 and 8 being isolated with high frequency from AIDS patients. However, it is unclear what role GPLs play in M. avium pathogenicity. To begin to address how the absence of GPLs affects M. avium-macrophage interaction, we used the well-characterized M. avium 2151 SmT and Rg isolates which differ in GPL expression. We found macrophages infected with the Rg compared with SmT M. avium 2151 showed prolonged activation of the mitogen-activated protein kinases (MAPKs) p38 and ERK1/2. Macrophages infected with the Rg 2151 also showed increased tumour necrosis factor-alpha (TNF-alpha) production. Interestingly, TNF-alpha secretion by macrophages infected with SmO or SmT 2151 was dependent on p38, ERK1/2 and NF-kappaB while TNF-alpha secretion by Rg 2151-infected macrophages was dependent on NF-kappaB but not the MAPKs. Rg 2151-infected macrophages also produced increased levels of IL-6, IL-12, MCP-1 and RANTES relative to macrophages infected with SmT 2151. These results indicate that M. avium 2151 deficient in GPLs promote increased macrophage activation. This disparity in cellular activation stems from a quantitative and qualitative difference in the macrophage signalling response to the Rg and SmT M. avium 2151.

Mycobacterium avium 104 deleted of the methyltransferase D gene by allelic replacement lacks serotype-specific glycopeptidolipids and shows attenuated virulence in mice

Mycobacterium avium is a major opportunistic pathogen of AIDS patients in the United States. The understanding of M. avium pathogenesis has been hampered by the inability to create gene knockouts by homologous recombination, an important mechanism for defining and characterizing virulence factors. In this study a functional methyltransferase D (mtfD) gene was deleted by allelic replacement in the M. avium strain 104. Methyltransferase D is involved in the methylation of glycopeptidolipids (GPLs); highly antigenic glycolipids found in copious amounts on the M. avium cell surface. Interestingly, the loss of mtfD resulted in M. avium 104 containing only the non-serotype specific GPL. Results also suggest that the mtfD encodes for a 3-O-methyltransferase. The absence of significant amounts of any serotype-specific GPLs as a consequence of mtfD deletion indicates that the synthesis of the core 3,4-di-O-methyl rhamnose is a prerequisite for synthesis of the serotype-specific GPLs. Macrophages infected with the mtfD mutant show elevated production of tumour necrosis factor-alpha (TNF-alpha) and RANTES compared to control infections. In addition, the M. avium 104 mtfD mutant exhibits decreased ability to survive/proliferate in mouse liver and lung compared to wild-type 104, as assessed by bacterial counts. Importantly, the mtfD mutant complemented with a wild-type mtfD gene maintained an infection level similar to wild-type. These experiments demonstrate that the loss of mtfD results in a M. avium 104 strain, which preferentially activates macrophages in vitro and shows attenuated virulence in mice. Together our data support a role for GPLs in M. avium pathogenesis.

HIV infection among paediatric in-patients in Blantyre, Malawi

To investigate the impact of HIV infection on hospital admission and death we studied children admitted to paediatric medical and surgical wards in Blantyre, Malawi, in March 2000. Unselected children whose parents or guardians consented to HIV testing of the child were recruited and HIV infection was determined by serology, with confirmation in children aged 15 months or less by PCR. We assessed the prevalence of HIV infection by age, clinical diagnosis and outcome of admission. Of 1064 admissions, 991 were tested for HIV infection, and 187 (18.9%) were infected. HIV was most common in children aged less than six months, 53 of 166 (32%). Parents of HIV-infected children were better educated, and more likely to have died, than those of uninfected children. Clinical symptoms and signs were not adequately sensitive or specific to be used for diagnosis of HIV. HIV was common in children with malnutrition (prevalence 40%), lower respiratory tract infection (29%) and sepsis (28%), and less prevalent among children with malaria (11%) or surgical admissions (11%). Almost 30% of HIV-infected children died, compared with 8.9% of uninfected children, and HIV-infected children constituted over 40% of in-patient deaths.

Antiparasitic therapy in children

Treatment of parasitic infections in children presents many challenges for the clinician. Although parasitic infections are ubiquitous on a worldwide basis, with an estimated 1 billion persons infected with intestinal helminthes alone, physicians in the United States and other developed countries are often unfamiliar with the management of these diseases. Children are traveling internationally in larger numbers than ever before, however, and emigration from developing countries to the United States and other Western countries is increasing, so clinicians in these countries are confronted more frequently with parasitic diseases from the tropics. This article describes current approaches to antiparasitic therapy. Drugs used in the treatment of more than one type of parasite are presented once in detail, with reference to the detailed description in subsequent sections.

Tuberculosis in HIV-infected children

Tuberculosis (TB) is the most common opportunistic infection in human immunodeficiency virus (HIV)-infected people worldwide. HIV-positive children are at risk of diagnostic error as well as delayed diagnosis of TB because of overlapping clinical and radiographic features with other lung diseases. Acute pneumonias and chronic lung diseases such as bronchiectasis and lymphocytic interstitial pneumonitis are difficult to distinguish from TB. TB manifestations are more severe in HIV-positive children and progression to death is more rapid than in HIV-negative children. The response to standard short-course therapy in HIV-positive children is not as good as in HIV-negative children due to lower cure rates and higher mortality. TB hastens the progression of HIV disease by increasing viral replication and reducing CD4 counts further. Although Bacille Calmette-Guerin vaccination could lead to disseminated Mycobacterium bovis disease in the presence of immunosuppression, this has been rarely reported. More studies are required to assess the role of newer diagnostic tests, TB preventive therapy and co-administration of anti-retroviral therapy in the control of TB among HIV-infected children.

Antimicrobial susceptibility and serotype distribution of Streptococcus pneumoniae and molecular characterization of multidrug-resistant serotype 19F, 6B, and 23F Pneumococci in northern Thailand

Penicillin-resistant Streptococcus pneumoniae is widely spread worldwide. Our study was undertaken to examine the susceptibility and serotypes of S. pneumoniae in northern Thailand. Ninety-three S. pneumoniae strains were isolated from 93 patients at Chiang Mai University Hospital, Chiang Mai, Thailand, from September 1999 to June 2000. The strains were isolated from sputum (n = 51), blood (n = 15), nasopharynges (n = 14), and other sources (e.g., pus, ears, ascites, and cerebrospinal fluid) (n = 13). Of the 93 isolates, 29 (31.2%) were susceptible, 24 (25.8%) showed intermediate resistance (MIC, 0.12 to 1.0 micro g/ml), and 40 (43.0%) were fully resistant (MIC, >/=2.0 micro g/ml) to penicillin G. Seven (46.7%) from blood, 5 (35.7%) from nasopharynges, 15 (29.4%) from sputum, and 2 (15.4%) from other sources were susceptible isolates. Serotyping with the use of antiserum revealed differences in the predominant types that were susceptible (6A, 11A, and 19A), intermediately resistant (6B and 23F), and fully resistant (6B, 19F, and 23F). Molecular typing by pulsed-field gel electrophoresis of multidrug-resistant pneumococci showed four patterns (A, B, C, and D) for 16 isolates of serotype 19F, with pattern B being predominant (12 isolates). This finding was different from that with the Taiwan multidrug-resistant serotype 19F clone. Eleven isolates of serotype 6B all showed pattern E, and nine isolates of serotype 23F showed two patterns (F and G), with pattern F being predominant (seven isolates). This finding was similar to that with the Spanish multidrug-resistant serotype 23F clone. Our results indicated that the resistance of pneumococci to antibiotics in northern Thailand is progressing rapidly and that effort should be intensified to prevent any spread of pandemic multidrug-resistant serotypes 19F, 6B, and 23F.

HIV and respiratory infections in children

Respiratory disease is a frequent cause of morbidity and mortality in children infected with human immunodeficiency virus (HIV). This review highlights recent data and developments that relate to the impact of HIV on respiratory infections particularly in African children. Autopsy and clinical studies continue to show that bacterial pneumonia and Pneumocystis jiroveci pneumonia (PCP) are common respiratory infections and causes of death in regions where antiretroviral therapy and PCP prophylaxis are not routinely practiced. Recent studies of Zambian and South African children showed that pulmonary tuberculosis is more common in HIV-infected children than was previously recognized. The trial of bacterial conjugate vaccines in Johannesburg will provide important information of efficacy in an HIV endemic population. Prospective clinical descriptive and intervention studies are needed from different regions to guide clinical management and prevention of respiratory infections in HIV-infected children living in resource-poor countries.

Characterization of genetic differences between Mycobacterium avium subsp. avium strains of diverse virulence with a focus on the glycopeptidolipid biosynthesis cluster

The Mycobacterium avium complex (MAC) encompasses important pathogens in both animals and humans, yet little information is available on the factors required for MAC virulence. An animal isolate, M. avium strain 724 was found to be considerably more virulent in Balb/c mice than a human isolate, M. avium strain A5. To identify the genetic basis of this difference subtractive hybridization was applied, which resulted in the isolation of six DNA fragments unique to strain 724. BLAST searches showed that three sequences belonged to a large gene cluster responsible for biosynthesis of M. avium glycopeptidolipids (GPLs). To reveal the nature of variation between strains in the GPL cluster 27.5kb of a clone containing the A5 serotype-specific GPL (ssGPL) cluster was isolated, sequenced and compared to the corresponding region in other M. avium strains. The ssGPL cluster was highly conserved in the 5' region between all strains and serotypes tested; the 3' region reflects extensive divergence among serotypes including whole gene deletions and insertions of sequences containing open reading frames but lacking identity to any known genes.

Serum immunoglobulin E levels in human immunodeficiency virus-infected children with pneumonia

Elevated serum immunoglobulin E (IgE) levels have been reported in association with human immunodeficiency virus (HIV) infection in adults, but there is little information in children. The aim of the present study was to compare serum IgE levels in HIV-positive and -negative children hospitalized with pneumonia in South Africa and to investigate whether IgE may be useful as a marker of specific infections or prognosis in HIV-infected children. History, examination, blood tests, and induced sputum or bronchoalveolar lavage were carried out. Of 122 children [45% female, median age 8 months (3-20 months)], 81 were infected with HIV. A history of allergy or asthma was present in three children (two of whom were HIV positive). Serum IgE was higher in HIV-infected children [83 (33-147) vs. 29 (6-113) IU/l; p = 0.011] as was immunoglobulin G (IgG) [49 (37-63) vs. 27.5 (23-34) g/l; p < 0.001]. CD4 lymphocytes [600 (330-1,210) vs. 1,900 (1,500-3,030) cells/ micro l], percentage CD4 cells [13.6 (9.4-20.3) vs. 40.1 (31.1-44.9)] and CD4 : CD8 ratio [0.3 (0.2-0.4) vs. 2 (1.4-2.8)] were lower in HIV-positive children (p < 0.001 for all). Bacteremia occurred in 12 (10%) children; other specific pathogens identified included Mycobacterium tuberculosis in eight (7%) and Pneumocystis carinii in nine (7%). There was no correlation with CD4 count, CD4 : CD8 ratio, or the presence of specific pathogens, and IgE level. In-hospital mortality (11%) did not correlate with IgE levels. HIV-infected children with pneumonia have higher serum IgE compared with seronegative patients. In HIV-positive children, IgE levels did not correlate with the degree of immunosuppression or with outcome.

The impact of HIV infection on childhood pneumonia: comparison between developed and developing regions

Respiratory disease is the commonest cause of morbidity and mortality in HIV-infected children. While the pattern of HIV-related pneumonia in African adults is well documented and is recognised as quite different from that which occurs among HIV-infected adults in high-income regions, less is known of the situation in children. Most children are infected by mother-to-child transmission and presentation of HIV-related pneumonia is often in infancy or early childhood, an age group in which confirmation of the cause of pneumonia is difficult. However, aetiological data are important. Poor response of the infant with severe pneumonia to standard antibiotic (such as chloramphenicol) or of the older child with chronic pneumonia to anti-tuberculosis treatment are two very common clinical dilemmas that many Malawian health workers would recognise. This review aims to present the available data relevant to Malawi, contrast with experience from the developed world and to describe common HIV-related pneumonias such as PCP and LIP. Unlike for adults, the pattern of HIV-related pneumonia in Malawian children may not be so different in cause from that described for children in developed countries prior to the use of PCP prophylaxis and anti-retroviral therapies. The most important contrast is the higher prevalence and poorer outcome.

Identification of Pneumocystis carinii DNA in oropharyngeal mouth washes from AIDS children dying of respiratory illnesses

Polymerase chain reaction (PCR) using Pneumocystis carinii-specific primers pAZ 102-H(5'-GTGTACGTTGCAAAGTACTC-3') and pAZ 102-E(5'-GATGGCTGTTTCCAAGCCCA-3') was performed on oropharyngeal washes obtained at autopsy from 22 AIDS children with histologically confirmed P. carinii pneumonia (PCP), and 48 control AIDS children who died from other infections. Fifteen of 22 (68%) PCP samples and none of 48 (0%) control samples had detectable P. carinii DNA (sensitivity 68%; specificity 100%; positive predictive value 100%; negative predictive value 87%). This method requires further validation in clinical practice.

HIV disease and respiratory infection in children

Over one million children world-wide are living with HIV infection and respiratory disease is the commonest cause of morbidity and mortality in these children. The initial presentation of respiratory infection is usually in infancy or early childhood. There is enormous potential to prevent childhood HIV infection that is being realised in industrialised countries but not yet elsewhere. Increasingly, therefore, the burden of HIV disease is in children living in or from non-industrialised countries. This review describes and contrasts the pattern of respiratory infection from both regions. This pattern has changed with the implementation of PCP prophylaxis and the availability of potent antiretroviral therapy for children in resource-rich countries, such as the UK. More data are required from resource-poor regions such as tropical Africa, but it is clear that the major differences reflect greater background risk for respiratory infection and very limited management options rather than specific aetiology.