Effectiveness of a multifaceted prevention programme for melioidosis in diabetics (PREMEL): A stepped-wedge cluster-randomised controlled trial

BACKGROUND: Melioidosis, an often-fatal infectious disease caused by the environmental Gram-negative bacillus Burkholderia pseudomallei, is endemic in tropical countries. Diabetes mellitus and environmental exposure are important risk factors for melioidosis acquisition. We aim to evaluate the effectiveness of a multifaceted prevention programme for melioidosis in diabetics in northeast Thailand. METHODOLOGY/PRINCIPAL FINDINGS: From April 2014 to December 2018, we conducted a stepped-wedge cluster-randomized controlled behaviour change trial in 116 primary care units (PCUs) in Ubon Ratchathani province, northeast Thailand. The intervention was a behavioural support group session to help diabetic patients adopt recommended behaviours, including wearing rubber boots and drinking boiled water. We randomly allocated the PCUs to receive the intervention starting in March 2016, 2017 and 2018. All diabetic patients were contacted by phone yearly, and the final follow-up was December 2018. Two primary outcomes were hospital admissions involving infectious diseases and culture-confirmed melioidosis. Of 9,056 diabetics enrolled, 6,544 (72%) received a behavioural support group session. During 38,457 person-years of follow-up, we observed 2,195 (24%) patients having 3,335 hospital admissions involved infectious diseases, 80 (0.8%) melioidosis, and 485 (5%) deaths. In the intention-to-treat analysis, implementation of the intervention was not associated with primary outcomes. In the per-protocol analysis, patients who received a behavioural support group session had lower incidence rates of hospital admissions involving infectious diseases (incidence rate ratio [IRR] 0.89; 95%CI 0.80-0.99, p = 0.03) and of all-cause mortality (IRR 0.54; 95%CI 0.43-0.68, p<0.001). However, the incidence rate of culture-confirmed melioidosis was not significantly lower (IRR 0.96, 95%CI 0.46-1.99, p = 0.66). CONCLUSIONS/SIGNIFICANCE: Clear benefits of this multifaceted prevention programme for melioidosis were not observed. More compelling invitations for the intervention, modification of or addition to the behaviour change techniques used, and more frequent intervention may be needed. TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov, number NCT02089152

Strong interferon-gamma mediated cellular immunity to scrub typhus demonstrated using a novel whole cell antigen ELISpot assay in rhesus macaques and humans

Scrub typhus is a febrile infection caused by the obligate intracellular bacterium Orientia tsutsugamushi, which causes significant morbidity and mortality across the Asia-Pacific region. The control of this vector-borne disease is challenging due to humans being dead-end hosts, vertical maintenance of the pathogen in the vector itself, and a potentially large rodent reservoir of unclear significance, coupled with a lack of accurate diagnostic tests. Development of an effective vaccine is highly desirable. This however requires better characterization of the natural immune response of this neglected but important disease. Here we implement a novel IFN-γ ELISpot assay as a tool for studying O. tsutsugamushi induced cellular immune responses in an experimental scrub typhus rhesus macaque model and human populations. Whole cell antigen for O. tsutsugamushi (OT-WCA) was prepared by heat inactivation of Karp-strain bacteria. Rhesus macaques were infected intradermally with O. tsutsugamushi. Freshly isolated peripheral blood mononuclear cells (PBMC) from infected (n = 10) and uninfected animals (n = 5) were stimulated with OT-WCA, and IFN-γ secreting cells quantitated by ELISpot assay at five time points over 28 days. PBMC were then assayed from people in a scrub typhus-endemic region of Thailand (n = 105) and responses compared to those from a partially exposed population in a non-endemic region (n = 14), and to a naïve UK population in UK (n = 12). Mean results at Day 0 prior to O. tsutsugamushi infection were 12 (95% CI 0-25) and 15 (2-27) spot-forming cells (SFC)/106 PBMC for infected and control macaques respectively. Strong O. tsutsugamushi-specific IFN-γ responses were seen post infection, with ELISpot responses 20-fold higher than baseline at Day 7 (mean 235, 95% CI 200-270 SFC/106 PBMC), 105-fold higher at Day 14 (mean 1261, 95% CI 1,097-1,425 SFC/106 PBMC), 125-fold higher at Day 21 (mean 1,498, 95% CI 1,496-1,500 SFC/106 PBMC) and 118-fold higher at Day 28 (mean 1,416, 95% CI 1,306-1,527 SFC/106 PBMC). No significant change was found in the control group at any time point compared to baseline. Humans from a scrub typhus endemic region of Thailand had mean responses of 189 (95% CI 88-290) SFC/106 PBMC compared to mean responses of 40 (95% CI 9-71) SFC/106 PBMC in people from a non-endemic region and 3 (95% CI 0-7) SFC/106 PBMC in naïve controls. In summary, this highly sensitive assay will enable field immunogenicity studies and further characterization of the host response to O. tsutsugamushi, and provides a link between human and animal models to accelerate vaccine development

Feasibility of Modified Surviving Sepsis Campaign Guidelines in a Resource-Restricted Setting Based on a Cohort Study of Severe S. Aureus Sepsis

[This corrects the article on p. e29858 in vol. 7.]

Clinical epidemiology of septic arthritis caused by Burkholderia pseudomallei and other bacterial pathogens in northeast Thailand

Septic arthritis is a medical emergency, and if not treated appropriately, it can be associated with high morbidity and mortality. Melioidosis, a serious infectious disease caused by the Gram-negative bacillus Burkholderia pseudomallei, is highly endemic in South and Southeast Asia and northern Australia. We reviewed the medical charts of adult patients admitted with bacterial septic arthritis at Sunpasitthiprasong Hospital, Ubon Ratchathani, northeast Thailand from January 2012 to December 2014. Bacterial septic arthritis was defined as one or more hot swollen joints with isolation of a pathogenic organism from an affected joint or from blood. A total of 154 patients with septic arthritis were retrospectively evaluated. The most common causes were B. pseudomallei (48%, N = 74), Streptococcus spp. (29%, N = 44), and Staphylococcus aureus (10%, N = 16). Prevalence of diabetes, bacteremia, and pneumonia was higher in B. pseudomallei septic arthritis than in septic arthritis caused by the other bacteria (all P &lt; 0.01). Seventy three percent (54/74) of patients infected with B. pseudomallei and 69% (55/80) of patients with the other bacteria received effective antimicrobials on the first day of admission (P = 0.60), but in-hospital mortality of the former group was considerably higher (34% versus 14%, P = 0.004). In conclusion, B. pseudomallei septic arthritis is common and associated with high mortality in northeast Thailand. Emergence of Streptococcus arthritis is observed. Difficulty in diagnosing melioidosis and identifying B. pseudomallei in areas where health care workers are not familiar with the disease is discussed. In melioidosis-endemic regions, parenteral ceftazidime could be considered as empirical antimicrobial therapy for patients with septic arthritis and underlying diseases

Clinical epidemiology of septic arthritis caused by Burkholderia pseudomallei and other bacterial pathogens in northeast Thailand

Septic arthritis is a medical emergency, and if not treated appropriately, it can be associated with high morbidity and mortality. Melioidosis, a serious infectious disease caused by the Gram-negative bacillus Burkholderia pseudomallei, is highly endemic in South and Southeast Asia and northern Australia. We reviewed the medical charts of adult patients admitted with bacterial septic arthritis at Sunpasitthiprasong Hospital, Ubon Ratchathani, northeast Thailand from January 2012 to December 2014. Bacterial septic arthritis was defined as one or more hot swollen joints with isolation of a pathogenic organism from an affected joint or from blood. A total of 154 patients with septic arthritis were retrospectively evaluated. The most common causes were B. pseudomallei (48%, N = 74), Streptococcus spp. (29%, N = 44), and Staphylococcus aureus (10%, N = 16). Prevalence of diabetes, bacteremia, and pneumonia was higher in B. pseudomallei septic arthritis than in septic arthritis caused by the other bacteria (all P < 0.01). Seventy three percent (54/74) of patients infected with B. pseudomallei and 69% (55/80) of patients with the other bacteria received effective antimicrobials on the first day of admission (P = 0.60), but in-hospital mortality of the former group was considerably higher (34% versus 14%, P = 0.004). In conclusion, B. pseudomallei septic arthritis is common and associated with high mortality in northeast Thailand. Emergence of Streptococcus arthritis is observed. Difficulty in diagnosing melioidosis and identifying B. pseudomallei in areas where health care workers are not familiar with the disease is discussed. In melioidosis-endemic regions, parenteral ceftazidime could be considered as empirical antimicrobial therapy for patients with septic arthritis and underlying diseases

Management and outcomes of severe dengue patients presenting with sepsis in a tropical country.

Background Dengue is a common cause of infection in adults in tropical countries. Sepsis is a syndrome of systemic manifestations induced by infection of any organisms; including bacterial, fungal and viral agents. Here, we investigated the diagnosis, management and outcomes of dengue patients presenting with sepsis in a prospective study of community-acquired sepsis in Thailand. Methods From June to December 2015, 874 adult patients (age≥18 years) with suspected or documented community-acquired infection, with ≥3 diagnostic criteria for sepsis according to the Surviving Sepsis Campaign 2012, and within 24 hours of admission were evaluated. Serum was stored and later tested for dengue PCR assays. Results A total of 126 patients had dengue PCR assays positive (2 DENV-1, 12 DENV-2, 24 DENV- 3 and 88 DENV-4), and 5 of them (4%) died. We found that attending physicians suspected dengue infection on admission in 84 patients (67%), and recorded dengue infection as the final diagnosis in 96 patients (76%). Four of five fatal cases were diagnosed and treated as septic shock not due to dengue. In multivariable analysis, there was a trend showing that age≥60 years, hypoxemia and misdiagnosis of dengue by attending physicians were associated with 28-day mortality. Conclusions A number of adult patients who died of dengue are misdiagnosed as severe sepsis and septic shock. Diagnosis of dengue based on clinical features alone is difficult. Rapid diagnostic tests for dengue may need to be routinely used in adult patients presenting with sepsis and septic shock in tropical countries. This approach could improve diagnosis and management of those patients.</p

Serum from melioidosis survivors diminished intracellular Burkholderia pseudomallei growth in macrophages: a brief research report

Melioidosis is a neglected tropical disease with high mortality rate. It is caused by the Gram-negative, CDC category B select agent Burkholderia pseudomallei (B. ps) that is intrinsically resistant to first-line antibiotics. An antibody-based vaccine is likely to be the most effective control measure. Previous studies have demonstrated significant mechanistic roles of antibodies in protection against death in animal models, but data from human melioidosis is scarce. Herein, we used in-vitro antibody-dependent cellular phagocytosis and growth inhibition assays to assess the mechanism of protective antibodies in patients with acute melioidosis. We found that serum from patients who survived the disease enable more live B. ps to be engulfed by THP-1 derived macrophages (median 1.7 &#xD7; 103 CFU/ml, IQR 1.1 &#xD7; 103-2.5 &#xD7; 103 CFU/ml) than serum from patients who did not survive (median 1.2 &#xD7; 103 CFU/ml, IQR 0.7 &#xD7; 103-1.8 &#xD7; 103, p = 0.02). In addition, the intracellular growth rate of B. ps pre-opsonized with serum from survivors (median 7.89, IQR 5.58-10.85) was diminished when compared with those with serum from non-survivors (median 10.88, IQR 5.42-14.88, p = 0.04). However, the difference of intracellular bacterial growth rate failed to reach statistical significance when using purified IgG antibodies (p = 0.09). These results provide new insights into a mechanistic role of serum in protection against death in human melioidosis for antibody-based vaccine development

Gastrointestinal tract involvement in melioidosis.

Background Little is known about the involvement of the human gut in carriage and disease associated with Burkholderia pseudomallei, the cause of melioidosis. Methods A hospital-based study was conducted in Northeast Thailand to culture stools or rectal swabs from patients with melioidosis, stools from controls with non-infectious diseases, and gastric biopsies from patients undergoing routine endoscopic investigation. Results and Conclusion B. pseudomallei was isolated from 9/83 (11%) stools and 9/58 (16%) rectal swabs from 141 patients with melioidosis. All stools from 244 control patients and 799 gastric biopsies from 395 patients with no evidence of melioidosis were culture negative for B. pseudomallei. It is not uncommon for melioidosis patients to shed B. pseudomallei in stool. Colonization of the gut of individuals without signs and symptoms of melioidosis may be rare.</p

Capacity and utilization of blood culture in two referral hospitals in Indonesia and Thailand

It is generally recommended that sepsis patients should have at least two blood cultures obtained before antimicrobial therapy. From 1995 to 2015, the number of blood cultures taken each year in a 1,100-bed public referral hospital in Ubon Ratchathani northeast Thailand rose from 5,235 to 56,719, whereas the number received in an 840-bed referral public hospital in south Sulawesi, Indonesia, in 2015 was 2,779. The proportion of patients sampled for blood cultures out of all inpatients in south Sulawesi in 2015 (9%; 2,779/30,593) was lower than that in Ubon Ratchathani in 2003 (13%; 8,707/66,515), at a time when health expenditure per capita in the two countries was comparable. Under-use of bacterial cultures may lead to an underestimate and underreporting of the incidence of antimicrobial-resistant infections. Raising capacity and utilization of clinical microbiology laboratories in developing countries, at least at sentinel hospitals, to monitor the antimicrobial resistance situation should be prioritized

Gastrointestinal tract involvement in melioidosis.

Background Little is known about the involvement of the human gut in carriage and disease associated with Burkholderia pseudomallei, the cause of melioidosis. Methods A hospital-based study was conducted in Northeast Thailand to culture stools or rectal swabs from patients with melioidosis, stools from controls with non-infectious diseases, and gastric biopsies from patients undergoing routine endoscopic investigation. Results and Conclusion B. pseudomallei was isolated from 9/83 (11%) stools and 9/58 (16%) rectal swabs from 141 patients with melioidosis. All stools from 244 control patients and 799 gastric biopsies from 395 patients with no evidence of melioidosis were culture negative for B. pseudomallei. It is not uncommon for melioidosis patients to shed B. pseudomallei in stool. Colonization of the gut of individuals without signs and symptoms of melioidosis may be rare.</p