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Biomedical subjects

Thira Sirisanthana

Publications and source records attributed to Thira Sirisanthana.

15 recordsLinked to original sources
PubMed2006

Prevalence of protective antibody against hepatitis B virus in HIV-infected children with immune recovery after highly active antiretroviral therapy.

HIV-infected children had a lower seroconversion rate to hepatitis B immunization and a more rapid antibody decline when compared to healthy children. Whether re-immunization or additional booster dose is necessary after immune recovery remains unknown. This study was conducted to determine the prevalence of hepatitis B virus protective antibody in HIV-infected children with immune recovery after highly active antiretroviral therapy (HAART). Serum hepatitis B viral markers were measured. An antibody level of > or =10 mIU/mL was defined as a protective antibody level. Only one out of 69 children (1%) had a protective antibody level. We concluded that despite the history of hepatitis B immunization and despite evidence of immune recovery after HAART, most HIV-infected children are still susceptible to HBV infection.

Antiretroviral Therapy, Highly Active↗
PubMed2006

Immune reconstitution syndrome after highly active antiretroviral therapy in human immunodeficiency virus-infected thai children.

BACKGROUND: There is little information about the immune reconstitution syndrome (IRS) in children, especially from resource-poor countries. OBJECTIVE: To determine the incidence and spectrum of IRS in advanced stage human immunodeficiency virus (HIV)-infected children after initiation of highly active antiretroviral therapy (HAART). METHODS: Between May 2002 and April 2004, 153 symptomatic HIV-infected children who had CD4 lymphocyte percentage < or =15% initiated HAART in a national antiretroviral drug access program. All patients were followed for 48 weeks. In this study, IRS was defined as a disease event caused by microorganisms or conditions previously reported to be associated with IRS in patients having immunologic and/or virologic response to HAART. RESULTS: The incidence of IRS was 19% (95% confidence interval, 13.1-26.1). The median time of onset was 4 weeks after start of HAART (range, 2-31). There were 32 episodes of IRS, including 14 caused by mycobacterial organisms, 7 by varicella-zoster virus, 7 by herpes simplex virus, 3 by Cryptococcus neoformans and 1 episode of Guillain-Barré syndrome. Patients who had IRS develop had lower baseline CD4 lymphocyte percentages compared with those who did not (P = 0.02). CONCLUSIONS: IRS is common among HIV-infected children who received HAART in their advanced stage of disease. Educational programs for patients and health care workers on recognizing and treating these conditions should be integrated into antiretroviral treatment access programs.

AIDS-Related Opportunistic Infections↗
PubMed2006

Immune reconstitution syndrome from nontuberculous mycobacterial infection after initiation of antiretroviral therapy in children with HIV infection.

The immune reconstitution syndrome caused by nontuberculous mycobacterial (NTM) infection is reported in 9 of 153 HIV-infected children 2 to 26 weeks after initiation of antiretroviral therapy. The clinical syndrome included fever and dyspnea (2 children), fever and abdominal pain (3), subcutaneous nodules or suppurative lymphadenitis (4). The causative species were Mycobacterium avium (4), Mycobacterium scrofulaceum (3), Mycobacterium kansasii (1) and Mycobacterium simiae (1).

Anti-Retroviral Agents↗
PubMed2006

Disclosure of HIV/AIDS diagnosis to HIV-infected children in Thailand.

BACKGROUND: With the availability of highly active antiretroviral therapy, more HIV-infected children have lived longer. Many children are at the age that they should know the diagnosis. AIM: To identify the prevalence and patterns of disclosure of HIV/AIDS diagnosis to HIV-infected children. METHODS: A cross-sectional study was conducted among 103 main care givers of HIV-infected children aged > or =6 years who received highly active antiretroviral therapy at Chiang Mai University and Sanpatong district hospitals, northern Thailand. RESULTS: One-third (30.1%) of the children knew their HIV/AIDS status at an average age of 9.2 years. The care givers' understanding of 'knowing' did not always mean that the children were told the name of 'HIV' or 'AIDS'. Many of those care givers (84.3%) who reported that the child did not know their diagnosis had inaccurately explained to the child that he or she had some kind of disease such as allergy, lung, or liver disease. The most common reason for non-disclosure was the fear that disclosure might have negative psychological consequences to the child (53.4%). Almost all (88.7%) agreed that they should tell the children their diagnosis in the future but half needed health-care providers to help them at the event. CONCLUSION: There is a need for the development of disclosure guide-lines and models for health-care providers and care givers as there was a high rate of inaccurate disclosure and, in addition, care givers expressed their need for assistance from health-care providers for the future disclosure.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Penicillium marneffei infection and recent advances in the epidemiology and molecular biology aspects.

Penicillium marneffei infection is an important emerging public health problem, especially among patients infected with human immunodeficiency virus in the areas of endemicity in southeast Asia, India, and China. Within these regions, P. marneffei infection is regarded as an AIDS-defining illness, and the severity of the disease depends on the immunological status of the infected individual. Early diagnosis by serologic and molecular assay-based methods have been developed and are proving to be important in diagnosing infection. The occurrence of natural reservoirs and the molecular epidemiology of P. marneffei have been studied; however, the natural history and mode of transmission of the organism remain unclear. Soil exposure, especially during the rainy season, has been suggested to be a critical risk factor. Using a highly discriminatory molecular technique, multilocus microsatellite typing, to characterize this fungus, several isolates from bamboo rats and humans were shown to share identical multilocus genotypes. These data suggest either that transmission of P. marneffei may occur from rodents to humans or that rodents and humans are coinfected from common environmental sources. These putative natural cycles of P. marneffei infection need further investigation. Studies on the fungal genetics of P. marneffei have been focused on the characterization of genetic determinants that may play important roles in asexual development, mycelial-to-yeast phase transition, and the expression of antigenic determinants. Molecular studies have identified several genes involved in germination, hyphal development, conidiogenesis, and yeast cell polarity. A number of functionally important genes, such as the malate synthase- and catalase-peroxidase protein-encoding genes, have been identified as being upregulated in the yeast phase. Future investigations pertaining to the roles of these genes in host-fungus interactions may provide the key knowledge to understanding the pathogenicity of P. marneffei.

Humans↗
PubMed2005

Immune reconstitution syndrome due to bacillus Calmette-Guérin after initiation of antiretroviral therapy in children with HIV infection.

The immune reconstitution syndrome caused by bacillus Calmette-Guerin (BCG) was found in 4 HIV-infected children who were immunized with BCG at birth. The localized, suppurative, BCG-related complications developed within 10 weeks after initiation of antiretroviral therapy. The incidence rate was 2.7 cases per 100 persons (95% confidence interval, 0.7-6.7). Patients responded well to treatment with isoniazid and rifampicin.

Anti-HIV Agents↗
PubMed2005

Efficacy of highly active antiretroviral therapy in HIV-infected children participating in Thailand's National Access to Antiretroviral Program.

BACKGROUND: Programs for access to antiretroviral treatment were only recently implemented in developing countries. This study aimed to describe the effect of highly active antiretroviral therapy (HAART) in treating human immunodeficiency virus (HIV)-infected children in Thailand's National Access to Antiretroviral Program for People Living with HIV/AIDS. METHODS: From August 2002 to July 2003, a total of 107 children were enrolled in the study. They received HAART consisting of either nevirapine or efavirenz, together with lamivudine and stavudine. Generic drugs and/or adult formulations were used. CD4 lymphocyte count, plasma HIV RNA level, and weight-for-age and height-for-age z scores were measured before, 2 months after, and every 6 months after initiation of HAART. A genotypic resistance assay was performed for patients with poor virological response. RESULTS: The mean age of the patients was 7.7 years (range, 2.1-13.8 years). At baseline, the median CD4 cell percentage was 3%, and the plasma HIV RNA level was 5.4 log10 copies/mL. Four patients died from HIV-related illness. After 72 weeks of HAART, the median CD4 cell percentage was 21%, and 76% of patients had HIV RNA levels of < 50 copies/mL. The mean weight-for-age and height-for-age z scores increased from -1.9 to -1.3 (P < .0001) and from -2.3 to -2.0 (P < .0001), respectively. The percentage of patients who took > or = 95% of prescribed medications during the interval between every follow-up visit was 86% For patients with suboptimal virological response, the most common resistance mutations among HIV isolates were associated with lamivudine and with nonnucleoside reverse-transcriptase inhibitors. CONCLUSION: In this resource-limited setting, HAART is safe and effective for HIV-infected children despite initiation of treatment during the advanced stage of disease. The use of generic and nonpediatric drug formulations is feasible.

Adolescent↗
PubMed2003

Molecular epidemiology of Rhodococcus equi of intermediate virulence isolated from patients with and without acquired immune deficiency syndrome in Chiang Mai, Thailand.

We investigated the prevalence of virulent Rhodococcus equi in clinical isolates from 69 sporadic cases (60 men, 8 women, and 1 patient of unknown sex) in Chiang Mai, Thailand, between 1993 and 2001. Fifty were human immunodeficiency virus (HIV) positive, 3 were HIV negative, and HIV status was unknown for 16. Fifty-two (75%) of 69 isolates were strains of intermediate virulence that contained the virulence-associated 20-kDa antigen, and 17 isolates (25%) were avirulent. No virulent strains with the virulence-associated 15-17-kDa antigens were identified. R. equi was isolated from HIV-positive patients' houses and those of their neighbors: avirulent strains were widespread, but only 1 strain of intermediate virulence was isolated. R. equi strains of intermediate virulence were isolated from 4 (0.8%) of 500 submaxillary lymph nodes from apparently healthy pigs in Chiang Mai. The routes of R. equi acquisition should be investigated from the viewpoint of zoonosis and public health.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Epidemiologic, clinical and laboratory features of scrub typhus in thirty Thai children.

BACKGROUND: Scrub typhus, a potentially fatal rickettsial infection, is common in Asia. Although serologic surveys suggested that as many as one-fourth of cases of scrub typhus might be in children, very few reports of childhood scrub typhus are available in the medical literature. OBJECTIVES: To document the clinical, laboratory and epidemiologic characteristics of pediatric patients with scrub typhus. METHODS: From January 1, 2000 to December 31, 2001, all pediatric patients at Chiang Mai University Hospital who had obscure fever for >5 days were tested for indirect immunofluorescent antibody (IFA) against Orientia tsutsugamushi, the causative organism of scrub typhus. Scrub typhus was diagnosed on the basis of either a single IFA titer against O. tsutsugamushi > or =1/400 or a 4-fold or greater rise in IFA titer to at least 1/200. RESULTS: Thirty children with scrub typhus were enrolled. Most were diagnosed during the rainy months of June to November. Common physical signs included lymphadenopathy (93%), hepatomegaly (73%), eschar (68%), conjunctival hyperemia (33%), maculopapular rash (30%) and splenomegaly (23%). Eleven patients had interstitial pneumonitis and 1 patient had meningitis. All patients responded well to doxycycline or chloramphenicol. The average interval to defervescence after treatment was 29 h (range, 6 to 72). CONCLUSIONS: Clinical and epidemiologic features of 30 pediatric patients with scrub typhus are reported in a prospective study. The presence of eschar was helpful in making the diagnosis. Complications included pneumonitis and meningitis. All cases responded well to treatment with antibiotic.

Adolescent↗
PubMed2003

Emergence of rifampin-resistant Rhodococcus equi with several types of mutations in the rpoB gene among AIDS patients in northern Thailand.

The antimicrobial susceptibilities of 30 Rhodococcus equi isolates obtained from 30 patients between 1993 and 2001 in northern Thailand were investigated. The MICs showed a tendency toward resistance to various antibiotics but sensitivity to imipenem, minocycline, vancomycin, and teicoplanin (MICs, </=0.5 micro g/ml) and relative sensitivity to meropenem, clarithromycin, and ciprofloxacin (MICs, </=2 micro g/ml). Of the 30 isolates, 26 were susceptible (MICs, </=1 micro g/ml), 1 showed low-level resistance (MIC, 8 micro g/ml), and 3 showed high-level resistance (MICs, >/=64 micro g/ml) to rifampin. PCR amplification and DNA sequencing of the rpoB gene and molecular typing by pulsed-field gel electrophoresis (PFGE) were performed for eight R. equi isolates from eight AIDS patients with pneumonia or lung abscess caused by R. equi between 1998 and 2001, including one low- and three high-level rifampin-resistant isolates. As a result, two high-level rifampin-resistant strains with PFGE pattern A had a Ser531Trp (Escherichia coli numbering) mutation, and one high-level rifampin-resistant strain with PFGE pattern B had a His526Tyr mutation, whereas one low-level rifampin-resistant strain with PFGE pattern C had a Ser509Pro mutation. Four rifampin-susceptible strains with PFGE patterns D and E showed an absence of mutation in the rpoB region. Our results indicate the presence of several types of rifampin-resistant R. equi strains among AIDS patients in northern Thailand.

AIDS-Related Opportunistic Infections↗
PubMed2003

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.

Drug Resistance, Multiple, Bacterial↗
PubMed2002

Anthrax of the gastrointestinal tract.

When swallowed, anthrax spores may cause lesions from the oral cavity to the cecum. Gastrointestinal anthrax is greatly underreported in rural disease-endemic areas of the world. The apparent paucity of this form of anthrax reflects the lack of facilities able to make the diagnosis in these areas. The spectrum of disease, ranging from subclinical infection to death, has not been fully recognized. In some community-based studies, cases of gastrointestinal anthrax outnumbered those of cutaneous anthrax. The oropharyngeal variant, in particular, is unfamiliar to most physicians. The clinical features of oropharyngeal anthrax include fever and toxemia, inflammatory lesion(s) in the oral cavity or oropharynx, enlargement of cervical lymph nodes associated with edema of the soft tissue of the cervical area, and a high case-fatality rate. Awareness of gastrointestinal anthrax in a differential diagnosis remains important in anthrax-endemic areas but now also in settings of possible bioterrorism.

Anthrax↗
PubMed2002

Identification of virulence-associated antigens and plasmids in Rhodococcus equi from patients with acquired immune deficiency syndrome and prevalence of virulent R. equi in soil collected from domestic animal farms in Chiang Mai, Thailand.

The prevalence of virulent Rhodococcus equi in soil collected from 17 domestic animal farms (from 12 cattle, 1 pig, and 4 horse farms) and in 6 clinical specimens from patients with acquired immune deficiency syndrome (AIDS) in Chiang Mai, Thailand, was investigated. The isolates were tested for the presence of 15-17-kDa antigens (VapA) and a 20-kDa antigen (VapB) by immunoblotting and for the presence of virulence plasmid DNA. Rhodococcus equi was isolated from most soil samples (68 of 80) obtained from the 17 farms, with 2.0 x 10(2) to 6.0 x 10(5) colony-forming units per gram of soil. We detected VapA in none of the 537 isolates from the soil samples. In one isolate from a pig farm, both VapB and virulence plasmid DNA were detected. Of the 6 clinical isolates from patients with AIDS, however, 4 isolates contained both VapB and virulence plasmid DNA. The remaining 2 isolates were avirulent.

AIDS-Related Opportunistic Infections↗
PubMed2001

A controlled trial of itraconazole as primary prophylaxis for systemic fungal infections in patients with advanced human immunodeficiency virus infection in Thailand.

Cryptococcal meningitis and Penicillium marneffei infection are common serious fungal infections in patients infected with human immunodeficiency virus (HIV) in Southeast Asia. In a prospective, double-blind trial, 63 patients with HIV infection and CD4+ lymphocyte counts of <200 cells/microL were randomized to receive oral itraconazole (200 mg per day), and 66 similar patients received a matched placebo. Both groups were monitored for evidence of invasive fungal infections. Baseline characteristics and the CD4+ cell counts of the 2 groups were similar. In the intent-to-treat analysis, a systemic fungal infection developed in 1 patient (1.6%) assigned to receive itraconazole (P. marneffei) and in 11 patients (16.7%) given placebo (7 patients had cryptococcal meningitis, and 4 patients had P. marneffei infection; P=.003, by the log-rank test). The incidence of recurrent or refractory mucosal candidiasis was significantly reduced in the itraconazole group. The 2 groups did not differ with regard to adverse effects. Primary prophylaxis with oral itraconazole is well tolerated and prevents cryptococcosis and penicilliosis marneffei in patients with advanced HIV infection, especially those with CD4+ lymphocyte counts of <100 cells/microL. However, prophylaxis with itraconazole was not found to be associated with a survival advantage when it was given to patients with advanced HIV disease.

Administration, Oral↗