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1.
Clin Infect Dis ; 2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33462580

RESUMO

BACKGROUND: Dengue is the most significant mosquito-borne viral disease; there are no specific therapeutics. The antiparasitic drug ivermectin efficiently inhibits the replication of all 4 dengue virus serotypes in vitro. METHODS: We conducted 2 consecutive randomized, double-blind, placebo-controlled trials in adult dengue patients to evaluate safety and virological and clinical efficacies of ivermectin. After a phase 2 trial with 2 or 3 days of 1 daily dose of 400 µg/kg ivermectin, we continued with a phase 3, placebo-controlled trial with 3 days of 400 µg/kg ivermectin. RESULTS: The phase 2 trial showed a trend in reduction of plasma nonstructural protein 1 (NS1) clearance time in the 3-day ivermectin group compared with placebo. Combining phase 2 and 3 trials, 203 patients were included in the intention to treat analysis (100 and 103 patients receiving ivermectin and placebo, respectively). Dengue hemorrhagic fever occurred in 24 (24.0%) of ivermectin-treated patients and 32 (31.1%) patients receiving placebo (P = .260). The median (95% confidence interval [CI]) clearance time of NS1 antigenemia was shorter in the ivermectin group (71.5 [95% CI 59.9-84.0] hours vs 95.8 [95% CI 83.9-120.0] hours, P = .014). At discharge, 72.0% and 47.6% of patients in the ivermectin and placebo groups, respectively had undetectable plasma NS1 (P = .001). There were no differences in the viremia clearance time and incidence of adverse events between the 2 groups. CONCLUSIONS: A 3-day 1 daily dose of 400 µg/kg oral ivermectin was safe and accelerated NS1 antigenemia clearance in dengue patients. However, clinical efficacy of ivermectin was not observed at this dosage regimen.

2.
PLoS Med ; 17(11): e1003393, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33211712

RESUMO

BACKGROUND: There is a high risk of Plasmodium vivax parasitaemia following treatment of falciparum malaria. Our study aimed to quantify this risk and the associated determinants using an individual patient data meta-analysis in order to identify populations in which a policy of universal radical cure, combining artemisinin-based combination therapy (ACT) with a hypnozoitocidal antimalarial drug, would be beneficial. METHODS AND FINDINGS: A systematic review of Medline, Embase, Web of Science, and the Cochrane Database of Systematic Reviews identified efficacy studies of uncomplicated falciparum malaria treated with ACT that were undertaken in regions coendemic for P. vivax between 1 January 1960 and 5 January 2018. Data from eligible studies were pooled using standardised methodology. The risk of P. vivax parasitaemia at days 42 and 63 and associated risk factors were investigated by multivariable Cox regression analyses. Study quality was assessed using a tool developed by the Joanna Briggs Institute. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42018097400). In total, 42 studies enrolling 15,341 patients were included in the analysis, including 30 randomised controlled trials and 12 cohort studies. Overall, 14,146 (92.2%) patients had P. falciparum monoinfection and 1,195 (7.8%) mixed infection with P. falciparum and P. vivax. The median age was 17.0 years (interquartile range [IQR] = 9.0-29.0 years; range = 0-80 years), with 1,584 (10.3%) patients younger than 5 years. 2,711 (17.7%) patients were treated with artemether-lumefantrine (AL, 13 studies), 651 (4.2%) with artesunate-amodiaquine (AA, 6 studies), 7,340 (47.8%) with artesunate-mefloquine (AM, 25 studies), and 4,639 (30.2%) with dihydroartemisinin-piperaquine (DP, 16 studies). 14,537 patients (94.8%) were enrolled from the Asia-Pacific region, 684 (4.5%) from the Americas, and 120 (0.8%) from Africa. At day 42, the cumulative risk of vivax parasitaemia following treatment of P. falciparum was 31.1% (95% CI 28.9-33.4) after AL, 14.1% (95% CI 10.8-18.3) after AA, 7.4% (95% CI 6.7-8.1) after AM, and 4.5% (95% CI 3.9-5.3) after DP. By day 63, the risks had risen to 39.9% (95% CI 36.6-43.3), 42.4% (95% CI 34.7-51.2), 22.8% (95% CI 21.2-24.4), and 12.8% (95% CI 11.4-14.5), respectively. In multivariable analyses, the highest rate of P. vivax parasitaemia over 42 days of follow-up was in patients residing in areas of short relapse periodicity (adjusted hazard ratio [AHR] = 6.2, 95% CI 2.0-19.5; p = 0.002); patients treated with AL (AHR = 6.2, 95% CI 4.6-8.5; p < 0.001), AA (AHR = 2.3, 95% CI 1.4-3.7; p = 0.001), or AM (AHR = 1.4, 95% CI 1.0-1.9; p = 0.028) compared with DP; and patients who did not clear their initial parasitaemia within 2 days (AHR = 1.8, 95% CI 1.4-2.3; p < 0.001). The analysis was limited by heterogeneity between study populations and lack of data from very low transmission settings. Study quality was high. CONCLUSIONS: In this meta-analysis, we found a high risk of P. vivax parasitaemia after treatment of P. falciparum malaria that varied significantly between studies. These P. vivax infections are likely attributable to relapses that could be prevented with radical cure including a hypnozoitocidal agent; however, the benefits of such a novel strategy will vary considerably between geographical areas.

3.
Am J Trop Med Hyg ; 103(5): 1834-1837, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32748775

RESUMO

Leptospira spp. are fastidious and slow-growing bacteria, making recovery difficult and diagnostic sensitivity in the clinical setting low. However, collection of Leptospira isolates is valuable for epidemiological and laboratory research. Severe leptospirosis cases may present as septic shock, and the differential diagnosis often includes bacterial septicemia, leading clinicians to collect blood cultures. Here, we report the successful isolation of pathogenic Leptospira spp. from blood culture bottles (targeting aerobic bacteria incubated at 37°C) from a 64-year-old man admitted with septic shock. The patient presented with 4 days of fever, severe hypotension, transient atrial fibrillation, jaundice, and oliguric renal failure. After admission, intravenous ceftriaxone plus azithromycin was given with fluid resuscitation, norepinephrine infusion, invasive mechanical ventilation, and renal replacement therapy. He was discharged from the hospital 16 days after admission. Using the blood sample obtained on admission, the diagnosis of leptospirosis was confirmed by multiplex real-time PCR (targeting bacterial 16S rRNA and LipL32 gene). We collected 200 µL from the blood culture bottle to inoculate a 5-mL Ellinghausen, McCullough, Johnson, and Harris media supplemented with 5% fetal bovine serum. After 2 weeks of incubation at 30°C, Leptospira strains were identified and confirmed by real-time PCR. Genotyping was undertaken using the multi-locus sequence typing (MLST) scheme#1. The isolate matched with ST50 isolates in the PUbMLST database. This case provides evidence that in tropical countries, severe leptospirosis should be considered in patients who present with symptoms of sepsis. Pathogenic Leptospira may be successfully isolated from aerobic blood cultures in routine clinical settings.


Assuntos
Leptospira/isolamento & purificação , Leptospirose/diagnóstico , Leptospirose/microbiologia , Choque Séptico/microbiologia , Antibacterianos/administração & dosagem , Antibacterianos/uso terapêutico , Azitromicina/administração & dosagem , Azitromicina/uso terapêutico , Hemocultura , Ceftriaxona/administração & dosagem , Ceftriaxona/uso terapêutico , Quimioterapia Combinada , Humanos , Masculino , Pessoa de Meia-Idade , Choque Séptico/diagnóstico
4.
Antibiotics (Basel) ; 8(3)2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31438510

RESUMO

Mycoplasma contamination detrimentally affects cellular functions and the growth of intracellular pathogens in cell cultures. Although several mycoplasmacidal agents are commercially available for sterile cell cultures, they are not applicable to rickettsia-infected cells. In our attempt to find an anti-mycoplasma drug for contaminated rickettsial cultures, we determined the susceptibilities of three common Mycoplasma species to daptomycin. Mycoplasma orale and M. arginini showed low-level resistance to daptomycin (minimum inhibitory concentration, MIC = 2 mg/L), whereas M. hyorhinis was high-level resistant (MIC = 32 mg/L). However, some Mycoplasma isolates developed higher resistance to daptomycin after failed treatments with inadequate doses or durations. An aminoglycoside (gentamicin) was still active against M. hyorhinis and could be used in Orientia cultures. For complete eradication of mycoplasmas in Rickettsia cultures, we recommend a 3-week treatment with daptomycin at 256 mg/L. In contaminated Orientia cultures, daptomycin at 32 mg/L was effective in eradicating M. orale, whereas either gentamicin or amikacin (100 mg/L) was effective in eradicating M. hyorhinis. Unlike each drug alone, the combinations of daptomycin plus clindamycin and/or quinupristin/dalfopristin proved effective in eradicating M. hyorhinis. In summary, our study demonstrated the in vitro anti-mycoplasma activity of daptomycin and its application as a new mycoplasma decontamination method for Rickettsia and Orientia cultures.

5.
PLoS One ; 14(4): e0215581, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31022229

RESUMO

BACKGROUND: Clinical courses and treatment outcomes are largely unknown in patients with adult-onset immunodeficiency associated with anti-interferon-gamma autoantibodies due to the fact that it was recently recognized and anti-IFN-γ auto-Abs detection is not widely available. METHODS AND FINDINGS: Non-HIV-infected adult patients with detectable anti-IFN-γ auto-Abs diagnosed and followed at Siriraj Hospital, Bangkok, Thailand during January 2013 to November 2016 were prospectively studied. At each follow-up visit, patients were classified as stable or active disease according to symptoms and signs, and all proven OIs were recorded. Laboratory parameters, including erythrocyte sedimentation rate, C-reactive protein, and anti-IFN-γ auto-Abs level, were compared between active and stable disease episodes. We identified 80 patients with this clinical syndrome and followed them up during study period. Seventy-nine patients developed overall 194 proven opportunistic infections. Mycobacterium abscessus (34.5%) and Salmonella spp. (23.2%) were the two most common pathogens identified among these patients. Sixty-three patients were followed for a median of 2.7 years (range 0.6-4.8 years). Eleven (17.5%) patients achieved the drug-free remission period for at least 9 months. Four patients died. Anti-IFN-γ auto-Abs concentration was significantly lower at baseline and decreased over time in the drug-free remission group compared to another group (p = 0.001). C-reactive protein, erythrocyte sedimentation rate and white cell count were found to be useful biomarkers for determining disease activity during follow-up. CONCLUSIONS: Reinfection or relapse of OIs is common despite long-term antimicrobial treatment in patients with anti-IFN-γ auto-Abs. Treatment to modify anti-IFN-γ auto-Abs production may improve long-term outcomes in this patient population.


Assuntos
Autoanticorpos/imunologia , Síndromes de Imunodeficiência/imunologia , Infecções por Mycobacterium não Tuberculosas/imunologia , Infecções Oportunistas/imunologia , Infecções por Salmonella/imunologia , Adulto , Idoso , Autoanticorpos/sangue , Biomarcadores/sangue , Sedimentação Sanguínea , Proteína C-Reativa/análise , Feminino , Seguimentos , Humanos , Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/diagnóstico , Interferon gama/imunologia , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/complicações , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Infecções Oportunistas/complicações , Infecções Oportunistas/diagnóstico , Estudos Prospectivos , Recidiva , Infecções por Salmonella/complicações , Infecções por Salmonella/diagnóstico , Tailândia , Adulto Jovem
6.
Parasit Vectors ; 12(1): 91, 2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30867022

RESUMO

BACKGROUND: Opportunistic infections represent a serious health problem for HIV-infected people. Among enteric infections, cryptosporidiosis, a severe and life-threatening diarrheal disease, is of particular importance in low economic settings where access to anti-retroviral therapy is limited. Understanding transmission routes is crucial in establishing preventive measures, and requires the use of informative genotyping methods. In this study, we performed a retrospective analysis of Cryptosporidium species in 166 stool samples collected from 155 HIV-infected patients during 1999-2004 at the Siriraj Hospital in Bangkok, Thailand. RESULTS: Microscopic examination of stools identified 104 of the 155 patients as positive for Cryptosporidium. Other common pathogens identified were microsporidia, Isospora, Giardia, Strongyloides and Opisthorchis. All samples were tested by amplification of a fragment of the 18S rDNA locus, and sequencing showed the presence of Cryptosporidium hominis (n = 42), C. meleagridis (n = 20), C. canis (n = 12), C. felis (n = 7), C. suis (n = 6) and C. parvum (n = 5). Genotyping at the glycoprotein 60 (gp60) locus revealed substantial variability in isolates of C. hominis and C. meleagridis. Among C. hominis isolates, subtype IeA11G3T3 was the most prevalent, but allelic family Id was the more diverse with four subtypes described, two of which were identified for the first time. Among C. meleagridis isolates, seven subtypes, two of which were new, were found in the allelic family IIIb, along with new subtypes in allelic families IIIe and IIIg. In the four C. parvum isolates, subtype IIoA16G1, a rare subtype previously reported in a Swedish patient who had traveled to Thailand, was identified. CONCLUSIONS: This study confirms the high susceptibility of HIV-infected individuals to infection with different Cryptosporidium species and subtypes, and further stresses the importance of surveillance for opportunistic intestinal protozoans.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/parasitologia , Criptosporidiose/parasitologia , Cryptosporidium/isolamento & purificação , Infecções por HIV/complicações , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Criptosporidiose/complicações , Criptosporidiose/epidemiologia , Cryptosporidium/genética , Suscetibilidade a Doenças , Genótipo , Técnicas de Genotipagem , Infecções por HIV/epidemiologia , Humanos , Tipagem Molecular , Estudos Retrospectivos , Tailândia/epidemiologia
7.
Vector Borne Zoonotic Dis ; 18(6): 297-302, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29683400

RESUMO

Rickettsia spp. has been detected in dog fleas in Bangkok, Thailand. With the intent of collecting evidence to confirm the presence of rickettsioses in dogs and to assess the level of associated potential for accidental human infection, human buffy coat from patients with fever of unknown origin (n = 168), whole blood samples from dogs (n = 353), and 19 flea groups from our dog sample population were studied during the 2012 to 2014 study period. The presence of Rickettsia was investigated by molecular detection of 23S rRNA gene of Rickettsia genus, citrate synthase (gltA) gene, and 17-kDa outer membrane gene. All positive samples were confirmed by DNA sequence analysis. Using phylogenetic analysis, three groups of Rickettsia were detected, as follows: Rickettsia felis in 8 patients and 8 dogs; R. felis-like sp. in 2 patients, 5 dogs, and 11 flea samples; and Rickettsia typhi in 3 patients. In addition to confirming the presence of R. felis in Thai patients, the findings of this study suggest that R. felis-like sp. isolated from fleas that were symbiotically coexisting with dogs that we evaluated in this study can transmit and cause disease in dogs and humans in Bangkok.


Assuntos
Infecções por Rickettsia/veterinária , Rickettsia/isolamento & purificação , Sifonápteros/microbiologia , Animais , Buffy Coat , Doenças do Cão/epidemiologia , Cães , Infestações por Pulgas/veterinária , Humanos , RNA Bacteriano/genética , RNA Ribossômico 23S/genética , Rickettsia/genética , Infecções por Rickettsia/epidemiologia , Infecções por Rickettsia/microbiologia , Tailândia/epidemiologia , Zoonoses
8.
Vaccine ; 36(2): 285-291, 2018 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-29191737

RESUMO

BACKGROUND: Obesity is a risk factor for increased morbidity and mortality associated with many vaccine preventable infectious diseases such as influenza. Moreover, higher volume of passive rabies immunoglobulin (RIG) due to weight based dosing might suppress vaccine-induced immune responses in obese patients. This study aimed to evaluate the effect of obesity on humoral immune responses to combined equine RIG and rabies vaccine treatment among patients with WHO category III exposure to a rabies suspected animal. METHODS: A single centre, prospective, open-labelled study among WHO category III rabies exposed patients was conducted to compare serum rabies virus neutralizing antibody (RVNA) responses measured by rapid fluorescent focus inhibition test between obese (body mass index, BMI > 30 kg/m2) and control (BMI < 25 kg/m2) patients after combined immunization with equine rabies immunoglobulin and purified chick-embryo cell rabies vaccine for post exposure prophylaxis treatment. RESULTS: Post-vaccination geometric mean titer (GMT) of RVNA concentrations between two groups at day 7 were 0.33 (95% CI: 0.23, 0.46) vs 0.39 (95% CI: 0.27, 0.55), 4.61 (95% CI: 3.20, 6.63) vs 3.78 (95% CI: 2.77, 5.16) at day 14, and 7.45 (95% CI: 5.86, 9.49) vs 5.93 (95%CI: 4.46-7.90) at day 28 for obese and control patients, respectively. There was no statistically significant difference of RVNA GMT between two groups. Seroconversion to at least adequate concentration (RVNA titer ≥0.5 IU/mL) rates were 34% at day 7 and 100% at days 14 and 28 in both groups. There were no immediate hypersensitivity reaction and no serious adverse events observed during the study period. CONCLUSIONS: There was no evidence of immunosuppression of antibodies' responses in obese patients. Combined ERIG and rabies virus vaccination for post exposure treatment is safe.


Assuntos
Anticorpos Antivirais/administração & dosagem , Anticorpos Antivirais/sangue , Obesidade/complicações , Profilaxia Pós-Exposição/métodos , Vacinas Antirrábicas/administração & dosagem , Vacinas Antirrábicas/imunologia , Raiva/prevenção & controle , Adulto , Idoso , Animais , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Estudos Prospectivos , Adulto Jovem
9.
BMC Infect Dis ; 17(1): 413, 2017 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-28601091

RESUMO

BACKGROUND: Scrub typhus (ST) is a disease caused by an obligate intracellular bacterium, Orientia tsutsugamushi, an organism that requires a BSL3 laboratory for propagation. The disease is hallmarked by an eschar at the site of the chigger bite, followed by the development of fever, malaise, myalgia, anorexia, and papulomacular rash. Indirect immunofluorescent assay (IFA) is the gold standard for scrub typhus diagnosis, however, the subjectivity of the assay, the need for a specialized laboratory and instruments has limited the wide use of the test in resource limited areas. METHODS: A recombinant-protein based enzyme linked immunosorbent assay (ELISA) using the most abundant and immunodominant protein for the detection of Orientia specific antibodies in serum has been developed. The performance of the assay was evaluated using prospectively collected acute sera from 248 randomly selected patients in Thailand. The ELISA assay was evaluated using two different cutoff values. RESULTS: The receiver operating characteristic (ROC) curve generated cutoff values gave slightly better consistency with diagnosis of ST than those cutoff values established by averaging ELISA optical density of known negatives at 99% confidence interval. Both cutoff values provided similar statistical parameters when compared with the diagnosis of ST, indicating the validity of both calculations to derive cutoff values. These results suggest that both IgG and IgM ELISA performed well to accurately diagnose scrub typhus cases in endemic areas using only acute serum samples. CONCLUSIONS: We have successfully developed an ELISA assay for the detection of Orientia-specific antibodies in serum that could provide effective screening of acute sera under clinical setup and it is also a useful assay to estimate seroprevalence in various endemic areas.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Orientia tsutsugamushi/genética , Tifo por Ácaros/diagnóstico , Animais , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Orientia tsutsugamushi/patogenicidade , Reação em Cadeia da Polimerase , Curva ROC , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Sensibilidade e Especificidade , Tailândia
11.
PLoS One ; 12(4): e0176342, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28437431

RESUMO

BACKGROUND: The clinical syndrome of disseminated nontuberculous mycobacterial (NTM) infection in patients who were previously healthy is now well recognized to be associated with an acquired autoantibody to Interferon gamma (Anti IFN- γ autoantibody). However, the risk factors of this syndrome remain unknown. METHOD: We performed an unmatched case control study among patients with NTM diseases who were diagnosed and treated at Siriraj Hospital, Bangkok, Thailand. Anti-IFN autoantibody was detected by enzyme-linked immunosorbent assay (ELISA) method. Cases were patients with NTM diseases and detectable anti IFN- γ autoantibody. Controls were randomly selected from those with undetectable anti IFN- γ autoantibody. Data from both groups including demographic data, clinical presentation, laboratory results, other risk factors and HLA genotypes were collected. Univariate and multivariate analyses were performed to identify independent risk factors for this syndrome. RESULTS: 70 cases (mean age 50 ± 11 years) and 70 controls (mean age 58 ± 18 years) were enrolled into the study. Mycobacterial abscessus was the most common NTM pathogen found in both groups (72.9% in cases and 41.4% in controls respectively). However, disseminated NTM disease was significantly more common in cases (92.9%) than in the controls (14.3%, p<0.001). Binary logistic regression analysis showed that previous OIs (adjusted OR14.87, 95% CI 2.36-93.86), birthplace outside Central region (adjusted OR 19.19, 95% CI 3.86-95.35), lack of comorbidities lead to immunosuppression, such as HIV infection or diabetes mellitus (adjusted OR 23.68, 95% CI 4.01-139.94), and presence of HLA DRB1*15/16 (adjusted OR 153.28, 95% CI 16.87-139.88) were independent factors associated with this syndrome. CONCLUSION: Patients with NTM disease associated with anti IFN- γ autoantibody are almost always previously healthy and HIV negative. Most of these patients presented with disseminated NTM disease with generalized lymphadenitis and often with reactive skin lesions. Factors associated with detectable anti IFN- γ autoantibody are HLA-DRB1 and DQB1 alleles, and history of previous OIs in patients without comorbidity that leads to immunosuppression. Further studies are needed to better understand these associations and to improve the treatment outcome.


Assuntos
Autoanticorpos/imunologia , Interferon gama/imunologia , Infecções por Mycobacterium não Tuberculosas/imunologia , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Cadeias beta de HLA-DQ/genética , Cadeias HLA-DRB1/genética , Humanos , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/genética
12.
J Clin Microbiol ; 55(5): 1377-1387, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28202789

RESUMO

Scrub typhus, caused by Orientia tsutsugamushi, is a common cause of acute undifferentiated febrile illness in the Asia-Pacific region. However, its nonspecific clinical manifestation often prevents early diagnosis. We propose the use of PCR and serologic tests as diagnostic tools. Here, we developed a multiplex real-time PCR assay using hydrolysis (TaqMan) probes targeting O. tsutsugamushi 47-kDa, groEL, and human interferon beta (IFN-ß gene) genes to improve early diagnosis of scrub typhus. The amplification efficiency was higher than 94%, and the lower detection limit was 10 copies per reaction. We used a human gene as an internal DNA quality and quantity control. To determine the sensitivity of this PCR assay, we selected patients with confirmed scrub typhus who exhibited a clear 4-fold increase in the level of IgG and/or IgM. The PCR assay result was positive in 45 of 52 patients, indicating a sensitivity of 86.5% (95% confidence interval [CI]: 74.2 to 94.4). The PCR assessment was negative for all 136 non-scrub typhus patients, indicating a specificity of 100% (95% CI: 97.3 to 100). In addition, this test helped diagnose patients with inconclusive immunofluorescence assay (IFA) results and using single blood samples. In conclusion, the real-time PCR assay proposed here is sensitive and specific in diagnosing scrub typhus. Combining PCR and serologic tests will improve the diagnosis of scrub typhus among patients presenting with acute febrile illness.


Assuntos
Proteínas de Bactérias/genética , Chaperonina 60/genética , Orientia tsutsugamushi/genética , Reação em Cadeia da Polimerase em Tempo Real/métodos , Tifo por Ácaros/diagnóstico , Ensaios de Anticorpos Bactericidas Séricos/métodos , Adulto , Anticorpos Antibacterianos/sangue , Carga Bacteriana/métodos , Proteínas de Bactérias/análise , Chaperonina 60/análise , Febre/diagnóstico , Febre/microbiologia , Amplificação de Genes , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Interferon beta/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Orientia tsutsugamushi/isolamento & purificação , Tifo por Ácaros/microbiologia , Sensibilidade e Especificidade
13.
Am J Trop Med Hyg ; 95(4): 769-773, 2016 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-27573633

RESUMO

Scrub typhus is endemic in Thailand. Of the 495 patients with acute undifferentiated fever studied in Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand, from June 1, 2011, to December 31, 2012, 146 patients (29.5%) had confirmed scrub typhus. The majority of cases were male, farmers, with the mean (±standard deviation) age of 54.1 ± 15.2 years. A total of 59 patients (40.4%) had eschar lesion. The commonest sites for an eschar in male patients were the perineum, inguinal, and buttock area; whereas in females, it was the head and neck area. Abnormal electrocardiogram was found in 39 of 79 patients (49.4%) with sinus tachycardia being the most frequent finding (17, 21.5%). A total of 73 patients (50%) had at least one complication. Myocarditis was the cause of complete heart block in a scrub typhus patient, and he fully recovered after receiving intravenous chloramphenicol treatment. The case fatality rate was 6.2% (nine deaths).The independent predictors for fatal outcome were age over 65 years (odds ratio [OR] = 14.49, 95% confidence interval [CI] = 1.26-166.44, P = 0.03), acute kidney injury (OR = 12.75, 95% CI = 1.77-92.07, P = 0.01), and hyperbilirubinemia (OR = 24.82, 95% CI = 2.12-286.61, P = 0.01). Early diagnosis and prompt appropriate treatment can improve the patient's outcome.


Assuntos
Antibacterianos/uso terapêutico , Cloranfenicol/uso terapêutico , Febre/etiologia , Orientia tsutsugamushi/isolamento & purificação , Tifo por Ácaros/epidemiologia , Lesão Renal Aguda/etiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Eletrocardiografia , Feminino , Febre/microbiologia , Humanos , Hiperbilirrubinemia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Estudos Prospectivos , Tifo por Ácaros/complicações , Tifo por Ácaros/mortalidade , Tifo por Ácaros/fisiopatologia , Tailândia/epidemiologia , Adulto Jovem
14.
Asian Pac J Trop Med ; 9(2): 141-4, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26919943

RESUMO

OBJECTIVE: To identify immunological evidence of Zika virus transmission in Thailand. METHODS: To undertake a preliminary serosurvey of possible exposure to Zika virus, 21 serum samples from cohort of acute undifferentiated fever patients were examined for immunoreactivity to Zika, Dengue, Japanese encephalitis and Chikungunya envelope antigens by Western blot analysis. RESULTS: Twenty of the 21 serum samples showed immunoreactivity to at least one of the antigens, with seven samples showing immunoreactivity to all antigens. Of particular note, two serum samples showed immunoreactivity only to Zika envelope antigen, with no immunoreactivity to other envelope antigens. CONCLUSIONS: This study presents the first evidence of Zika virus transmission in Thailand, although as yet the relationship between transmission and possible cases of Zika fever in Thailand requires further investigation.

16.
BMC Microbiol ; 15: 205, 2015 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-26449888

RESUMO

BACKGROUND: There is an urgent need for a simple and accurate test for the diagnosis of human Mycobacterium tuberculosis, the infectious agent causing tuberculosis (TB). Here we describe a serological test based on light emitting recombinant proteins for the diagnosis of pulmonary Mycobacterium tuberculosis infection. METHODS: Luciferase Immunoprecipitation Systems (LIPS), a fluid-phase immunoassay, was used to examine antibody responses against a panel of 24 different M. tuberculosis proteins. Three different strategies were used for generating the constructs expressing the recombinant fusion M. tuberculosis proteins with luciferase: synthetic gene synthesis, Gateway recombination cloning, and custom PCR synthesis. A pilot cohort of African pulmonary TB patients was used for initial antibody screening and confirmatory studies with selected antigens were performed with a cohort from Thailand and healthy US blood donors. In addition to testing M. tuberculosis antigens separately, a mixture that tested seven antigens simultaneously was evaluated for diagnostic performance. RESULTS: LIPS testing of a pilot set of serum samples from African pulmonary TB patients identified a potential subset of diagnostically useful M. tuberculosis antigens. Evaluation of a second independent cohort from Thailand validated highly significant antibody responses against seven antigens (PstS1, Rv0831c, FbpA, EspB, bfrB, HspX and ssb), which often showed robust antibody levels up to 50- to 1000-fold higher than local community controls. Marked heterogeneity of antibody responses was observed in the patients and the combined results demonstrated 73.5% sensitivity and 100% specificity for detection of pulmonary TB. A LIPS test simultaneously employing the seven M. tuberculosis antigen as a mixture matched the combined diagnostic performance of the separate tests, but showed an even higher diagnostic sensitivity (90%) when a cut-off based on healthy US blood donors was used. CONCLUSION: A LIPS immunoassay employing multiple M. tuberculosis antigens shows promise for the rapid and quantitative serological detection of pulmonary TB.


Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Imunoprecipitação/métodos , Mycobacterium tuberculosis/imunologia , Testes Sorológicos/métodos , Tuberculose Pulmonar/diagnóstico , África , Estudos de Coortes , Humanos , Luciferases/análise , Projetos Piloto , Sensibilidade e Especificidade , Tailândia , Estados Unidos
17.
J Infect Dev Ctries ; 9(7): 760-4, 2015 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-26230127

RESUMO

INTRODUCTION: Fever is a common symptom of many tropical diseases and in many cases the etiologic agent remains unidentified as a consequence of either the etiologic agent not being part of routine diagnostic screening or as a consequence of false negatives on standard diagnostic tests. METHODOLOGY: This study screened a well characterized panel of 274 serum samples collected on day of admission from adult patients with acute undifferentiated fever admitted to a hospital in Nakhon Ratchasima, Thailand by RT-PCR using pan-flavivirus degenerate primers. RESULTS: Subsequent clinical diagnosis was achieved for 38 of the patients, and included 19 cases of dengue fever. RT-PCR screening identified seven positive samples (2.5%) which were revealed by sequence analysis to be dengue virus 1 (2 cases), dengue virus 2 (2 cases) and dengue virus 3 (3 cases). Only 5 out of 19 (26%) serum samples from patients subsequently diagnosed with dengue were positive, but 2 samples which clinically remained undiagnosed were shown to be positive for dengue virus. Sequence analysis suggested that the dengue virus 3 cases occurred as a result of importation of a strain of dengue from India or China. No other flaviviruses were identified. CONCLUSIONS: No evidence was found of other flaviviruses besides dengue circulating in this population. Despite improved diagnostic tests, cases of dengue are still evading correct diagnosis.


Assuntos
Vírus da Dengue/isolamento & purificação , Febre de Causa Desconhecida/diagnóstico , Infecções por Flaviviridae/diagnóstico , Programas de Rastreamento/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Soro/virologia , Adulto , Primers do DNA/genética , Vírus da Dengue/genética , Hospitais , Humanos , Estudos Prospectivos , Estudos Retrospectivos , Tailândia
18.
PLoS One ; 10(5): e0128481, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26011559

RESUMO

Recently a newly identified clinical syndrome of disseminated non-tuberculous mycobacterial diseases (with or without other opportunistic infections in adult patients who were previously healthy, has been recognized in association with an acquired autoantibody to interferon-gamma. This syndrome is emerging as an important cause of morbidity and mortality, especially among people of Asian descent. Trigger for the production of this autoantibody remains unknown, but genetic factors are strongly suspected to be involved. We compared HLA genotyping between 32 patients with this clinical syndrome, and 38 controls. We found that this clinical syndrome was associated with very limited allele polymorphism, with HLA-DRB1 and DQB1 alleles, especially HLA-DRB1*15:01, DRB1*16:02, DQB1*05:01 and DQB1*05:02. Odds ratio of DRB1*15:01, DRB1*16:02, DQB1*05:01 and DQB1*05:02 were 7.03 (95% CI, 2.18-22.69, P<0.0001, 9.06 (95% CI, 2.79-29.46, P<0.0001), 6.68 (95% CI, 2.29-19.52, P = 0.0004), and 6.64 (95% CI, 2.30-19.20, P = 0.0004), respectively. Further investigation is warranted to provide better understanding on pathogenesis of this association.


Assuntos
Autoanticorpos/sangue , Cadeias beta de HLA-DQ/genética , Cadeias HLA-DRB1/genética , Interferon gama/imunologia , Infecções por Mycobacterium não Tuberculosas/genética , Adulto , Idade de Início , Idoso , Grupo com Ancestrais do Continente Asiático/genética , Feminino , Estudos de Associação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Infecções por Mycobacterium não Tuberculosas/sangue , Infecções por Mycobacterium não Tuberculosas/imunologia , Polimorfismo Genético , Tailândia
19.
Infect Genet Evol ; 31: 1-8, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25577986

RESUMO

Orientia tsutsugamushi is the causative agent of scrub typhus, a major cause of febrile illness in rural area of Asia-Pacific region. A multi-locus sequence typing (MLST) analysis was performed on strains isolated from human patients from 3 countries in Southeast Asia: Cambodia, Vietnam and Thailand. The phylogeny of the 56-kDa protein encoding gene was analyzed on the same strains and showed a structured topology with genetically distinct clusters. MLST analysis did not lead to the same conclusion. DNA polymorphism and phylogeny of individual gene loci indicated a significant level of recombination and genetic diversity whereas the ST distribution indicated the presence of isolated patches. No correlation was found with the geographic origin. This work suggests that weak divergence in core genome and ancestral haplotypes are maintained by permanent recombination in mites while the 56-kDa protein gene is diverging in higher speed due to selection by the mammalian immune system.


Assuntos
Haplótipos , Orientia tsutsugamushi/classificação , Orientia tsutsugamushi/genética , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/microbiologia , Ásia Sudeste/epidemiologia , Evolução Molecular , Genes Bacterianos , Humanos , Tipagem de Sequências Multilocus , Orientia tsutsugamushi/isolamento & purificação , Filogenia , Polimorfismo Genético , Seleção Genética
20.
Int J Bacteriol ; 2015: 147173, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26904743

RESUMO

Leptospirosis is a worldwide zoonosis caused by an infection with the pathogenic species of Leptospira. We have developed a loop-mediated isothermal amplification (LAMP) assay to detect the DNA of Leptospira spp. Six sets of primers targeting the gene of the subsurface protein, lipL32, were evaluated for their detection sensitivity. The best primer set detected less than 25 copies of lipL32 per reaction of both plasmid DNA template and purified leptospiral genomic DNA. By combining primers targeting lipL32 with the previously published primer set targeting lipL41, the sensitivity of the assay was improved to 12 copies of L. interrogans. The specificity of the LAMP assay was evaluated by using the genomic DNA from other clinically encountered bacterial species such as different strains of Orientia tsutsugamushi, Rickettsia typhi, Rickettsia conorii, Rickettsia rickettsii, Coxiella burnetii, and Bartonella bacilliformis. These genomic DNA samples were all negative in our LAMP assay. The sensitivity of the LAMP assay was very similar to that of quantitative real time PCR. Several detection methods for the amplified product of LAMP assay were performed to demonstrate the simplicity of the assay. In summary, our results have suggested that this assay is rapid, robust, and easy to perform and has the potential to be used in endemic locations.

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