[show abstract][hide abstract] ABSTRACT: Melioidosis, caused by Burkhoderia pseudomallei, results in substantial morbidity and mortality in Thailand with an estimated case fatality rate of 40%. Delays in isolation and identification contribute to this high mortality, as B. pseudomallei are slow growing bacteria and commonly mistaken for Gram-negative contaminants. As part of the Pneumonia Etiology Research for Child Health (PERCH) study, a multi-site investigation of severe childhood pneumonia, we sought to enhance detection of B. pseudomallei at the two participating hospitals in Thailand, one in the highly endemic Northeast Thailand (Nakhon Phanom) and one in eastern Thailand (Sa Kaeo). Five specimens (nasopharyngeal swab, blood, induced sputum, throat swab, and urine) were collected from participants: children aged <5 years hospitalized with severe or very severe pneumonia. Blood was cultured using automated machines. Nasopharyngeal swab, throat swab, sputum and urine were enriched by Ashdown’s broth, a selective medium for B. pseudomallei, incubated for 48 hours then plated onto sheep blood agar, chocolate agar and MacConkey agar, which incubated for another 96 hours. Additionally, all specimens were cultured on Ashdown’s agar directly. All oxidase-positive Gram-negative bacilli were evaluated using latex agglutination test for B. pseudomallei, which was shown to have 95% sensitivity and 100% specificity, and then standard biochemical methods. Of the 269 cases enrolled to date, 77 (28.6%) had at least one clinical sample culture positive for oxidase-positive Gram-negative bacilli (3, 37, 32, 35 and 58 from blood, nasopharyngeal swab, throat swab, sputum and urine, respectively). None were B. pseudomallei. These preliminary results are limited by small sample size, but suggest that B. pseudomallei is not a common pathogen among children under five with severe pneumonia. Additional data are needed from at least one more rainy season, when melioidosis cases typically peak.
7th World Melioidosis Conference, 2013 (http://www.wmc2013.org/), Bangkok Thailand; 09/2013
[show abstract][hide abstract] ABSTRACT: Pneumonia remains a leading cause of under-five morbidity and mortality globally. Comprehensive incidence, epidemiologic, and etiologic data are needed to update prevention and control strategies.
We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory infections (ALRI) among children aged <5 years in rural Thailand. ALRI cases were systematically sampled for an etiology study that tested nasopharyngeal specimens by PCR; children without ALRI were enrolled as controls from outpatient clinics.
We identified 28,543 hospitalized ALRI cases from 2005-2010. Among the 49% with chest radiographs, 76% had findings consistent with pneumonia as identified by two study radiologists. The hospitalized ALRI incidence rate (IR) was 5,772 per 100,000 child-years (95% CI 5,707, 5,837), and was higher in boys vs. girls (IR Ratio (IRR) 1.38, 95% CI 1.35, 1.41) and in children aged 6-23 months vs. other age groups (IRR 1.76, 95% CI 1.69, 1.84). Viruses most commonly detected in ALRI cases were respiratory syncytial virus (RSV, 19.5%), rhinoviruses (18.7%), bocavirus (12.8%), and influenza viruses (8%). Compared to controls, ALRI cases were more likely to test positive for RSV, influenza, adenovirus, human metapneumovirus, and parainfluenza viruses 1 and 3 (p≤0.01 for all). Bloodstream infections, most commonly Streptococcus pneumoniae and non-typhoidal Salmonella, accounted for 1.8% of cases.
Our findings underscore the high burden of hospitalization for ALRI and the importance of viral pathogens among children in Thailand. Interventions targeting viral pathogens coupled with improved diagnostic approaches, especially for bacteria, are critical for better understanding of ALRI etiology, prevention and control.
The Pediatric Infectious Disease Journal 09/2013; · 3.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: SUMMARY Acinetobacter is a well-recognized nosocomial pathogen. Previous reports of community-associated Acinetobacter infections have lacked clear case definitions and assessment of healthcare-associated (HCA) risk factors. We identified Acinetobacter bacteraemia cases from blood cultures obtained <3 days after hospitalization in rural Thailand and performed medical record reviews to assess HCA risk factors in the previous year and compare clinical and microbiological characteristics between cases with and without HCA risk factors. Of 72 Acinetobacter cases, 32 (44%) had no HCA risk factors. Compared to HCA infections, non-HCA infections were more often caused by Acinetobacter species other than calcoaceticus-baumannii complex species and by antibiotic-susceptible organisms. Despite similar symptoms, the case-fatality proportion was lower in non-HCA than HCA cases (9% vs. 45%, P < 0·01). Clinicians should be aware of Acinetobacter as a potential cause of community-associated infections in Thailand; prospective studies are needed to improve understanding of associated risk factors and disease burden.
Epidemiology and Infection 09/2013; · 2.87 Impact Factor
[show abstract][hide abstract] ABSTRACT: Streptococcus pneumoniae is an important cause of morbidity and mortality in Southeast Asia, but regional data is limited. Updated burden estimates are critical as pneumococcal conjugate vaccine (PCV) is highly effective, but not yet included in the Expanded Program on Immunization of Thailand or neighboring countries.
We implemented automated blood culture systems in two rural Thailand provinces as part of population-based surveillance for bacteremia. Blood cultures were collected from hospitalized patients as clinically indicated.
From May 2005- March 2010, 196 cases of pneumococcal bacteremia were confirmed in hospitalized patients. Of these, 57% had clinical pneumonia, 20% required mechanical ventilation, and 23% (n = 46) died. Antibiotic use before blood culture was confirmed in 25% of those with blood culture. Annual incidence of hospitalized pneumococcal bacteremia was 3.6 per 100,000 person-years; rates were higher among children aged <5 years at 11.7 and adults ≥65 years at 14.2, and highest among infants <1 year at 33.8. The median monthly case count was higher during December-March compared to the rest of the year 6.0 vs. 1.0 (p<0.001). The most common serotypes were 23F (16%) and 14 (14%); 61% (74% in patients <5 years) were serotypes in the 10-valent PCV (PCV 10) and 82% (92% in <5 years) in PCV 13. All isolates were sensitive to penicillin, but non-susceptibility was high for co-trimoxazole (57%), erythromycin (30%), and clindamycin (20%).
We demonstrated a high pneumococcal bacteremia burden, yet underestimated incidence because we captured only hospitalized cases, and because pre-culture antibiotics were frequently used. Our findings together with prior research indicate that PCV would likely have high serotype coverage in Thailand. These findings will complement ongoing cost effectiveness analyses and support vaccine policy evaluation in Thailand and the region.
PLoS ONE 01/2013; 8(6):e66038. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Members of the Gram-negative genus Legionella are typically found in freshwater environments, with the exception of L. longbeachae, which is present in composts and potting mixes. When contaminated aerosols are inhaled, legionellosis may result, typically as either the more serious pneumonia Legionnaires' disease or the less severe flu-like illness Pontiac fever. It is presumed that all species of the genus Legionella are capable of causing disease in humans. As a followup to a prior clinical study of legionellosis in rural Thailand, indigenous soil samples were collected proximal to cases' homes and workplaces and tested for the presence of legionellae by culture. We obtained 115 isolates from 22/39 soil samples and used sequence-based methods to identify 12 known species of Legionella represented by 87 isolates.
International Journal of Microbiology 01/2012; 2012:218791.
[show abstract][hide abstract] ABSTRACT: The purpose of this investigation was to enhance the detection of pneumococcal bacteremia cases using the Binax NOW® immunochromatographic test (ICT) on blood culture broth as part of surveillance in two rural Thailand provinces. Blood cultures were collected as clinically indicated from hospitalized patients. ICT was performed on broth from culture bottles flagged as positive by BactT/ALERT® (alarm-positive) but which failed to grow organisms on subculture. During the period May 2005-June 2007, ICT was positive on 43 (24%) of 182 alarm-positive blood cultures with no growth on subculture. Compared to pneumococcal bacteremia cases confirmed by culture, cases detected only by ICT had a longer median time from culture collection to incubation and a longer median time from alarm positivity to subculture, and were more likely to be from patients pretreated with antibiotics. In a subsequent surveillance period (July 2007-December 2009), ICT continued to detect additional pneumococcal cases, but in a lower proportion of samples (7 of 221, 3.2%). Recently, as part of a separate study, ICT applied to uninoculated blood culture broth produced weak-positive results, mandating caution if testing broth from patient blood cultures. The antigen testing of blood culture broth appears to enhance the detection of pneumococcal bacteremia, but a controlled evaluation is needed.
European Journal of Clinical Microbiology 08/2011; 31(5):753-6. · 3.02 Impact Factor
[show abstract][hide abstract] ABSTRACT: Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in northeastern Thailand. Population-based disease burden estimates are lacking and limited data on melioidosis exist from other regions of the country. Using active, population-based surveillance, we measured the incidence of bacteremic melioidosis in the provinces of Sa Kaeo (eastern Thailand) and Nakhon Phanom (northeastern Thailand) during 2006-2008. The average annual incidence in Sa Kaeo and Nakhon Phanom per 100,000 persons was 4.9 (95% confidence interval [CI] = 3.9-6.1) and 14.9 (95% CI = 13.3-16.6). The respective population mortality rates were 1.9 (95% CI = 1.3-2.8) and 4.4 (95% CI = 3.6-5.3) per 100,000. The case-fatality proportion was 36% among those with known outcome. Our findings document a high incidence and case fatality proportion of bacteremic melioidosis in Thailand, including a region not traditionally considered highly endemic, and have potential implications for clinical management and health policy.
The American journal of tropical medicine and hygiene 07/2011; 85(1):117-20. · 2.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: No studies have quantified the impact of pre-culture antibiotic use on the recovery of individual blood-borne pathogens or on population-level incidence estimates for Streptococcus pneumoniae. We conducted bloodstream infection surveillance in Thailand during November 2005-June 2008. Pre-culture antibiotic use was assessed by reported use and by serum antimicrobial activity. Of 35,639 patient blood cultures, 27% had reported pre-culture antibiotic use and 24% (of 24,538 tested) had serum antimicrobial activity. Pathogen isolation was half as common in patients with versus without antibiotic use; S. pneumoniae isolation was 4- to 9-fold less common (0.09% versus 0.37% by reported antibiotic use; 0.05% versus 0.45% by serum antimicrobial activity, P < 0.01). Pre-culture antibiotic use by serum antimicrobial activity reduced pneumococcal bacteremia incidence by 32% overall and 39% in children < 5 years of age. Our findings highlight the limitations of culture-based detection methods to estimate invasive pneumococcal disease incidence in settings where pre-culture antibiotic use is common.
The American journal of tropical medicine and hygiene 08/2010; 83(2):301-6. · 2.53 Impact Factor
[show abstract][hide abstract] ABSTRACT: Population-based estimates of the incidence of invasive pneumococcal disease are unavailable for Thailand and other countries in Southeast Asia. We estimated the incidence of pneumococcal bacteremia cases requiring hospitalization in rural Thailand.
Blood cultures were performed on samples from hospitalized patients in 2 rural provinces where active, population-based surveillance of community-acquired pneumonia is conducted. Blood cultures were performed at clinician discretion and were encouraged for all patients with suspected pneumonia and all children aged <5 years with suspected sepsis. Pneumococcal antigen testing was performed on positive blood culture specimens that failed to grow organisms on subculture.
From May 2005 through June 2007, 23,853 blood culture specimens were collected overall, and 7319 were collected from children aged <5 years, which represented 66% and 47% of target patients, respectively. A total of 72 culture-confirmed pneumococcal bacteremia cases requiring hospitalization were identified. An additional 44 patients had media from positive blood cultures that yielded no growth on subculture but that had positive results of pneumococcal antigen testing. Of the 116 confirmed cases of bacteremia, 27 (23%) occurred in children aged <5 years; of these, 9 (33%) were confirmed by antigen testing only. The incidence of pneumococcal bacteremia cases requiring hospitalization among children aged <5 years had a range of 10.6-28.9 cases per 100,000 persons (incidence range if cases detected by antigen are excluded, 7.5-14.0 cases per 100,000 persons).
Invasive pneumococcal disease is more common than was previously suspected in Thailand, even on the basis of estimates limited to hospitalized cases of bacteremia. These estimates, which are close to estimates of the incidence of hospitalized cases of pneumococcal bacteremia in the United States before introduction of pneumococcal conjugate vaccine, provide important data to guide public health care policy and to inform discussions about vaccine introduction in Thailand and the rest of Southeast Asia.