The Predictive Factors Associated with In-Hospital Mortality of Melioidosis: A Cohort Study.

Background and Objectives: Melioidosis is an infectious disease caused by Burkholderia pseudomallei, and it has a wide range of clinical symptoms. It is endemic in tropical areas, including Southeast Asia. Despite the availability of effective treatment, the mortality rate is still high, especially in patients presenting with septic shock. The aim of this study was to determine and explore clinical characteristics, microbiology, treatment outcomes, and factors associated with in-hospital mortality which could predict prognosis and provide a guide for future treatment. Materials and Methods: The population in this retrospective cohort study included all 262 patients with a diagnosis of melioidosis who were hospitalized at Surin Hospital, Surin, Thailand, from April 2014 to March 2017. We included patients older than 15 years with a positive culture for B. pseudomallei. Data regarding the clinical characteristics, microbiology, and treatment outcomes of the patients were collected and analyzed. The patients were divided into two groups dependent on outcome, specifically non-survival and survival. Logistic regression was performed to determine the risk factors associated with in-hospital mortality. Results: Out of the 262 patients with melioidosis during the study period, 117 (44.7%) patients died. The mean age was 57.2 ± 14.4 years, and 193 (73.7%) patients were male. The most common comorbidity was diabetes (123, 46.9%), followed by chronic kidney disease (35, 13.4%) and chronic liver disease (31, 11.8%). Four risk factors were found to be associated with in-hospital mortality, including age (adjusted odds ratio (aOR) 1.04, 95%CI: 1.01-1.07), respiration rate (aOR 1.18, 95%CI: 1.06-1.32), abnormal chest X-ray finding (aOR 4.79, 95%CI: 1.98-11.59), and bicarbonate levels (CO2) (aOR 0.92, 95%CI: 0.85-0.99). Conclusions: Our study identified age, respiration rate, abnormal chest X-ray finding, and CO2 levels are predictive factors associated with in-hospital mortality in melioidosis patients. Physicians should be aware of these factors, have access to aggressive treatment options, and closely monitor patients with these risk factors.

Lack of Association of TLR1 and TLR5 Coding Variants with Mortality in a Large Multicenter Cohort of Melioidosis Patients.

Melioidosis, infection caused by Burkholderia pseudomallei, is characterized by robust innate immune responses. We have previously reported associations of TLR1 single nucleotide missense variant rs76600635 with mortality and of TLR5 nonsense variant rs5744168 with both bacteremia and mortality in single-center studies of patients with melioidosis in northeastern Thailand. The objective of this study was to externally validate the associations of rs76600635 and rs5744168 with bacteremia and mortality in a large multicenter cohort of melioidosis patients. We genotyped rs76600635 and rs5744168 in 1,338 melioidosis patients enrolled in a prospective parent cohort study conducted at nine hospitals in northeastern Thailand. The genotype frequencies of rs76600635 did not differ by bacteremia status (P = 0.27) or 28-day mortality (P = 0.84). The genotype frequencies of rs5744168 did not differ by either bacteremia status (P = 0.46) or 28-day mortality (P = 0.10). Assuming a dominant genetic model, there was no association of the rs76600635 variant with bacteremia (adjusted odds ratio [OR], 0.75; 95% CI, 0.54-1.04, P = 0.08) or 28-day mortality (adjusted OR, 0.96; 95% CI, 0.71-1.28, P = 0.77). There was no association of the rs5744168 variant with bacteremia (adjusted OR, 1.24; 95% CI, 0.76-2.03, P = 0.39) or 28-day mortality (adjusted OR, 1.22; 95% CI, 0.83-1.79, P = 0.21). There was also no association of either variant with 1-year mortality. We conclude that in a large multicenter cohort of patients hospitalized with melioidosis in northeastern Thailand, neither TLR1 missense variant rs76600635 nor TLR5 nonsense variant rs5744168 is associated with bacteremia or mortality.

Statin Use and Reduced Risk of Pneumonia in Patients with Melioidosis: A Lung-Specific Statin Association.

Rationale: 3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) use is associated with a lower risk of incident pneumonia and, less robustly, with nonpulmonary infections. Whether statin use is associated with a lower risk of pneumonia than other clinical presentations of infection with the same pathogen is unknown. Objectives: To assess whether preadmission statin use is associated with a lower risk of pneumonia than nonpneumonia presentations among patients hospitalized with Burkholderia pseudomallei infection (melioidosis). Methods: We performed a secondary analysis of a prospective multicenter cohort study of patients hospitalized with culture-confirmed B. pseudomallei infection (melioidosis). We used Poisson regression with robust standard errors to test for an association between statin use and pneumonia. We then performed several sensitivity analyses that addressed healthy user effect and indication bias. Results: Of 1,372 patients with melioidosis enrolled in the parent cohort, 1,121 were analyzed. Nine hundred eighty (87%) of 1,121 were statin nonusers, and 141 (13%) of 1,121 were statin users. Forty-six (33%) of 141 statin users presented with pneumonia compared with 432 (44%) of 980 statin nonusers. Statin use was associated with a lower risk of pneumonia in unadjusted analysis (relative risk, 0.74; 95% confidence interval, 0.58-0.95; P = 0.02) and, after adjustment for demographic variables, comorbidities, environmental exposures, and symptom duration (relative risk, 0.73; 95% confidence interval, 0.57-0.94; P = 0.02). The results of sensitivity analyses, including active comparator analysis and inverse probability of treatment weighting, were consistent with the primary analysis. Conclusions: In hospitalized patients with melioidosis, preadmission statin use was associated with a lower risk of pneumonia than other clinical presentations of melioidosis, suggesting a lung-specific protective effect of statins.

Characteristics and One Year Outcomes of Melioidosis Patients in Northeastern Thailand: A Prospective, Multicenter Cohort Study.

Background: Melioidosis is a neglected tropical infection caused by the environmental saprophyte Burkholderia pseudomallei. Methods: We conducted a prospective, observational study at nine hospitals in northeastern Thailand, a hyperendemic melioidosis zone, to define current characteristics of melioidosis patients and quantify outcomes over one year. Findings: 2574 individuals hospitalised with culture-confirmed melioidosis were screened and 1352 patients were analysed. The median age was 55 years, 975 (72%) were male, and 951 (70%) had diabetes. 565 (42%) patients presented with lung infection, 1042 (77%) were bacteremic, 442 (33%) received vasopressors/inotropes and 547 (40%) received mechanical ventilation. 1307 (97%) received an intravenous antibiotic against B. pseudomallei. 335/1345 (25%) patients died within one month and 448/1322 (34%) of patients died within one year. Most patients had risk factors for melioidosis, but patients without identified risk factors did not have a reduced risk of death. Of patients discharged alive, most received oral trimethoprim-sulfamethoxazole, which was associated with decreased risk of post-discharge death; 235/970 (24%) were readmitted, and 874/1015 (86%) survived to one year. Recurrent infection was detected in 17/994 patients (2%). Patients with risk factors other than diabetes had increased risk of death and increased risk of hospital readmission. Interpretation: In northeastern Thailand patients with melioidosis experience high rates of bacteremia, organ failure and death. Most patients discharged alive survive one year although all-cause readmission is common. Recurrent disease is rare. Strategies that emphasize prevention, rapid diagnosis and intensification of early clinical management are likely to have greatest impact in this and other resource-restricted regions. Funding: US NIH/NIAID U01AI115520.

Antibiotic susceptibility of clinical Burkholderia pseudomallei isolates in northeast Thailand during 2015-2018 and the genomic characterization of ß-lactam-resistant isolates.

Melioidosis is an often fatal infection in tropical regions caused by an environmental bacterium, Burkholderia pseudomallei Current recommended melioidosis treatment requires intravenous ß-lactam antibiotics such as ceftazidime (CAZ), meropenem (MEM) or amoxicillin-clavulanic acid (AMC) and oral trimethoprim-sulfamethoxazole. Emerging antibiotic resistance could lead to therapy failure and high mortality. We performed a prospective multicentre study in northeast Thailand during 2015-2018 to evaluate antibiotic susceptibility and characterize ß-lactam resistance in clinical B. pseudomallei isolates. Collection of 1,317 B. pseudomallei isolates from patients with primary and relapse infections were evaluated for susceptibility to CAZ, imipenem (IPM), MEM and AMC. ß-lactam resistant isolates were confirmed by broth microdilution method and characterized by whole genome sequence analysis, penA expression and ß-lactamase activity. The resistant phenotype was verified via penA mutagenesis. All primary isolates were IPM-susceptible but we observed two CAZ-resistant and one CAZ-intermediate resistant isolates, two MEM-less susceptible isolates, one AMC-resistant and two AMC-intermediate resistant isolates. One of 13 relapse isolates was resistant to both CAZ and AMC. Two isolates were MEM-less susceptible. Strains DR10212A (primary) and DR50054E (relapse) were multi-drug resistant. Genomic and mutagenesis analyses supplemented with gene expression and ß-lactamase analyses demonstrated that CAZ-resistant phenotype was caused by PenA variants: P167S (N=2) and penA amplification (N=1). Despite the high mortality rate in melioidosis, our study revealed that B. pseudomallei isolates had a low frequency of ß-lactam resistance caused by penA alterations. Clinical data suggest that resistant variants may emerge in patients during antibiotic therapy and be associated with poor response to treatment.

Implementation of Clinical Practice Guidelines for Empirical Antibiotic Therapy of Bacteremia, Urinary Tract Infection, and Pneumonia: A Multi-Center Quasi-Experimental Study.

A quasi-experimental study was conducted on the implementation of locally developed clinical practice guidelines (CPGs) for empirical antibiotic (ATB) therapy of common infections (bacteremia, urinary tract infection (UTI), pneumonia) in the hospitals from January 2019 to December 2020. The CPGs were developed using data from patients with these infections at individual hospitals. Relevant CPG data pre- and post-implementation were collected and compared. Of the 1644 patients enrolled in the study, 808 and 836 were in the pre- and post-implementation periods, respectively, and patient outcomes were compared. Significant reductions in the mean durations of intensive care unit stay (3.44 ± 9.08 vs. 2.55 ± 7.89 days; p = 0.035), ventilator use (5.73 ± 12.14 vs. 4.22 ± 10.23 days; p = 0.007), piperacillin/tazobactam administration (0.954 ± 3.159 vs. 0.660 ± 2.217 days, p = 0.029), and cefoperazone/sulbactam administration (0.058 ± 0.737 vs. 0.331 ± 1.803 days, p = 0.0001) occurred. Multivariate analysis demonstrated that CPG-implementation was associated with favorable clinical outcomes (adjusted odds ratio 1.286, 95% confidence interval: 1.004-1.647, p = 0.046). Among patients who provided follow-up cultures (n = 284), favorable microbiological responses were significantly less frequent during the pre-implementation period than the post-implementation period (80.35% vs. 91.89%; p = 0.01). In conclusion, the locally developed CPG implementation is feasible and effective in improving patient outcomes and reducing ATB consumption. Hospital antimicrobial stewardship teams should be able to facilitate CPG development and implementation for antimicrobial therapy for common infections.

Incidence of active tuberculosis among people living with HIV receiving long-term antiretroviral therapy in high TB/HIV burden settings in Thailand: implication for tuberculosis preventive therapy.

INTRODUCTION: Among high tuberculosis (TB) and HIV burden countries in Asia, tuberculosis preventive therapy (TPT) in people living with HIV (PLWH) has been underutilized despite its proven benefits independent of antiretroviral therapy (ART). Therefore, we determined the incidence of active TB and mortality among 9179 adult PLWH who attended and received ART from 15 tertiary care hospitals across Thailand. METHODS: A retrospective study was conducted in 2018 using follow-up data from 1999 to 2018. The primary endpoint was incident TB disease after ART initiation. Factors associated with TB incidence were analysed using competing risk regression. The Kaplan-Meier method was used to estimate mortality after ART initiation. RESULTS: During a median of 5.1 years of ART (IQR 2.2-9.5 years), 442 (4.8%) PLWH developed TB (TB/HIV), giving an overall incidence of 750 (95% CI 683-823) per 100,000 persons-year of follow up (PYFU). In multivariate analysis, lower CD4 at ART initiation (≤100 cells/mm3 , adjusted sub-distribution hazard ratio [aSHR]: 2.08, 95% CI, 1.47-2.92; 101-200 cells/mm3 , aSHR: 2.21, 95% CI, 1.54-3.16; 201-350 cells/mm3 , aSHR: 1.59, 95% CI, 1.11-2.28 vs. >350 cells/mm3 ), male sex (aSHR: 1.40, 95% CI, 1.11-1.78), lower body weight (<50 kg, aSHR: 1.52, 95% CI, 1.17-1.95) and prior TB event (aSHR: 3.50, 95% CI, 2.72-4.52) were associated with TB incidence. PLWH with HIV RNA ≥50 copies/ml had 5-9 times higher risk of active TB disease higher than those with HIV RNA <50 copies/ml at the same CD4 level. The risk for developing TB was remarkably high during the initial period of ART (175,511 per 100,000 PYFU at<3 months) and was comparable to the general population after 10 years of ART (151 per 100,000 PYFU). TB/HIV had higher mortality (10% vs. 5%) and poorer HIV treatment outcomes: HIV RNA <50 copies/ml (63.8% vs. 82.8%), CD4 cells count (317 vs. 508 cells/mm3 ) at the most recent visit. CONCLUSIONS: In this high TB burden country, TB incidence was remarkably high during the first few years after ART initiation and thereafter decreased significantly. Rapid ART initiation and appropriate TPT can be potential key interventions to tackle the TB epidemic and reduce mortality among PLWH in TB/HIV high burden settings.

Feasibility, Challenges, and Benefits of Global Antimicrobial Resistance Surveillance System Implementation: Results from a Multicenter Quasi-Experimental Study.

The Global Antimicrobial Resistance Surveillance System (GLASS) is one of the pillars of the global action plan on antimicrobial resistance launched by the World Health Organization in 2015. This study was conducted to determine the feasibility and benefits of GLASS as a component of antimicrobial stewardship strategies in three provincial hospitals in Thailand. Data on the types of bacteria isolated and their antibiotic susceptibility during January-December 2019 and January-April 2020 were retrieved from the microbiology laboratory of each participating hospital. Laboratory-based antibiograms from 2019 and GLASS-based antibiograms from 2020 were created and compared. A total of 14,877 and 3580 bacterial isolates were obtained during January-December 2019 and January-April 2020, respectively. The common bacteria isolated in both periods were Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus. Hospital-acquired infection (HAI)-related bacteria were observed in 59.0%, whereas community-acquired infection (CAI)-related bacteria were observed in 41.0% of isolates. Antibiotic resistance in CAIs was high and may have been related to the misclassification of colonized bacteria as true pathogens and HAIs as CAIs. The results of this study on AMR surveillance using GLASS methodology may not be valid owing to several inadequate data collections and the problem of specimen contamination. Given these considerations, related personnel should receive additional training on the best practices in specimen collection and the management of AMR surveillance data using the GLASS approach.

Impact of Antibiotic Authorisation at Three Provincial Hospitals in Thailand: Results from a Quasi-Experimental Study.

Implementing antimicrobial stewardship (AMS) at non-university hospitals is challenging. A quasi-experimental study was conducted to determine the impact of customised antibiotic authorisation implementation on antimicrobial consumption and clinical outcomes at three provincial hospitals in Thailand. Customised pre-authorisation of selected restricted antibiotics and post-authorisation of selected controlled antibiotics were undertaken and implemented at each hospital by the local AMS team with guidance from the AMS team at the university hospital. From January 2019−December 2020, there were 1802 selected patients (901 patients during the pre-implementation period and 901 patients during the post-implementation period). The most commonly used targeted antimicrobial was meropenem (49.61%), followed by piperacillin/tazobactam (36.46%). Comparison of the outcomes of the patients during the pre- and post-implementation periods revealed that the mean day of therapy of the targeted antimicrobials was significantly shorter during the post-implementation period (6.24 vs. 7.64 days; p < 0.001), the favourable clinical response (the improvement in all clinical and laboratory parameters at the end of antibiotic therapy) was significantly higher during the post-implementation period (72.70% vs. 68.04%; p = 0.03) and the mean length of hospital stay was significantly shorter during the post-implementation period (15.78 vs. 18.90 days; p < 0.001). In conclusion, implementation of antibiotic authorisation at provincial hospitals under experienced AMS team's guidance was feasible and useful. The study results could be a good model for the implementation of customised AMS strategies at other hospitals with limited resources.

Occurrence of mcr-mediated colistin resistance in Salmonella clinical isolates in Thailand.

Nontyphoidal Salmonella, an important zoonotic pathogen and a major cause of foodborne illnesses, could be a potential reservoir of plasmids harbouring mobile colistin resistance gene (mcr). This study reported, for the first time, a high rate of mcr-carrying Salmonella clinical isolates (3.3%, 24/724) in Thailand, associated with mcr-3 gene (3.0%, 22/724) in S. 4,[5],12:i:-(15.4%, 4/26), S. Typhimurium (8.8%, 5/57), and S. Choleraesuis (5.6%, 13/231). Remarkably, the increasing trends of colistin and extended-spectrum cephalosporin resistances have displayed a high agreement over the years, with a dramatic rise in the mcr-carrying Salmonella from 1.1% (6/563) during 2005-2007 to 11.2% (18/161) during 2014-2018 when CTX-M-55 became abundant. Clonal and plasmid analysis revealed that the self-transferable IncA/C and a novel hybrid IncA/C-FIIs MDR plasmids were the major vehicles to disseminate both mcr-3 and blaCTX-M55 genes among diverse Salmonella strains, from as early as 2007. To our knowledge the occurrence of mcr-3 and the co-existence of it with blaCTX-M-55 in S. Choleraesuis are reported here for the first time, leading to clinical concern over the treatment of the invasive salmonellosis. This study provides evidence of the potential reservoirs and vectors in the dissemination of the mcr and highlights the co-selection by colistin and/or cephalosporins.

Blood transcriptomics to characterize key biological pathways and identify biomarkers for predicting mortality in melioidosis.

Melioidosis is an often lethal tropical disease caused by the Gram-negative bacillus, Burkholderia pseudomallei. The study objective was to characterize transcriptomes in melioidosis patients and identify genes associated with outcome. Whole blood RNA-seq was performed in a discovery set of 29 melioidosis patients and 3 healthy controls. Transcriptomic profiles of patients who did not survive to 28 days were compared with patients who survived and healthy controls, showing 65 genes were significantly up-regulated and 218 were down-regulated in non-survivors compared to survivors. Up-regulated genes were involved in myeloid leukocyte activation, Toll-like receptor cascades and reactive oxygen species metabolic processes. Down-regulated genes were hematopoietic cell lineage, adaptive immune system and lymphocyte activation pathways. RT-qPCR was performed for 28 genes in a validation set of 60 melioidosis patients and 20 healthy controls, confirming differential expression. IL1R2, GAS7, S100A9, IRAK3, and NFKBIA were significantly higher in non-survivors compared with survivors (P < 0.005) and healthy controls (P < 0.0001). The AUROCC of these genes for mortality discrimination ranged from 0.80-0.88. In survivors, expression of IL1R2, S100A9 and IRAK3 genes decreased significantly over 28 days (P < 0.05). These findings augment our understanding of this severe infection, showing expression levels of specific genes are potential biomarkers to predict melioidosis outcomes.

Genomic characterization of an emerging blaKPC-2 carrying Enterobacteriaceae clinical isolates in Thailand.

The rapidly increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) over the past decade has increased concern in healthcare facilities and the impact on public health. The prevalence of blaKPC (KPC) in Thailand remains very low; only blaKPC-13 has been described previously. This study is the first to describe the characteristics of blaKPC-2-carrying Klebsiella pneumoniae, Escherichia coli, and Enterobacter asburiae in Thailand. The prevalence rate of blaKPC-2-carrying isolates was 0.13% among CRE isolates in our study. Based on carbapenem susceptibility testing, K. pneumoniae C1985 was resistant to meropenem and ertapenem, E. coli C1992 was resistant to meropenem, imipenem, and ertapenem, and E. asburiae C2135 was only resistant to imipenem. K. pneumoniae C1985 carried blaKPC-2, blaSHV-11, fosA, oqxA, and oqxB, while E. coli C1992 contained blaKPC-2 and mdf(A) and E. asburiae C2135 harbored blaKPC-2, blaACT-2, and qnrE1. The genetic features of blaKPC-2 in the 3 isolates revealed identical rearrangement and flanking regions. Analysis of genomic sequences from these 3 isolates revealed that the sequence types of K. pneumoniae C1985, E. coli C1992, and E. asburiae C2135 were ST4008, ST7297, and ST1249, respectively. The 3 blaKPC-2 isolates were from individual living cases. Two cases were colonization for K. pneumoniae C1985 and E. asburiae C2135 and the third case was hospital-acquired infection of E. coli C1992. Although the prevalence of blaKPC-2-carrying CRE is relatively low in this study, continued surveillance and close monitoring are warranted. In addition, prompt or early detection of CRE and strict implementation of infection control are essential to prevent outbreaks or rapid spread in hospitals.