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Burkholderia pseudomallei is a Gram-negative bacillus and the etiological agent of melioidosis in humans and animals. The disease is highly endemic in northern Australia and Southeast Asia. Comprehensive genomic data are essential for understanding the bacteria's dissemination and genetic relationships among strains from different geographical regions. In this study, we conducted antimicrobial susceptibility testing and whole-genome sequencing of 54 B. pseudomallei isolates obtained from environmental and animal sources in southern Thailand between 2011 and 2018. Their genomics were determined of antibiotic-resistant genes (ARGs), virulence-associated genes, mobile genetic elements (MGEs), sequence types (STs), and single nucleotide polymorphisms (SNPs) to evaluate their epidemiological relatedness. Remarkably, all 54 isolates displayed sensitivity to antimicrobial agents typically used for melioidosis treatment. We identified nine distinct sequence types: ST392, ST51, ST409, ST508, ST376, ST1721, ST389, ST395, and ST289. Oxacillinase genes and the resistance nodulation family of efflux pumps (RND) were identified as contributors to antimicrobial resistance. Phylogenetic analysis demonstrated close genetic relations with other strains isolated from Southeast Asia. Furthermore, 172 virulence-associated genes were identified among the isolates, suggesting variations in clinical presentations. These findings underscore the importance of ongoing molecular genetic surveillance of B. pseudomallei for effective healthcare management and reducing melioidosis mortality., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Burkholderia pseudomallei, a Gram-negative pathogen, causes melioidosis. Although various clinical laboratory identification methods exist, culture-based techniques lack comprehensive evaluation. Thus, this systematic review and meta-analysis aimed to assess the diagnostic accuracy of culture-based automation and non-automation methods., Methods: Data were collected via PubMed/MEDLINE, EMBASE, and Scopus using specific search strategies. Selected studies underwent bias assessment using QUADAS-2. Sensitivity and specificity were computed, generating pooled estimates. Heterogeneity was assessed using I 2 statistics., Results: The review encompassed 20 studies with 2988 B. pseudomallei samples and 753 non-B. pseudomallei samples. Automation-based methods, particularly with updating databases, exhibited high pooled sensitivity (82.79%; 95% CI 64.44-95.85%) and specificity (99.94%; 95% CI 98.93-100.00%). Subgroup analysis highlighted superior sensitivity for updating-database automation (96.42%, 95% CI 90.01-99.87%) compared to non-updating (3.31%, 95% CI 0.00-10.28%), while specificity remained high at 99.94% (95% CI 98.93-100%). Non-automation methods displayed varying sensitivity and specificity. In-house latex agglutination demonstrated the highest sensitivity (100%; 95% CI 98.49-100%), followed by commercial latex agglutination (99.24%; 95% CI 96.64-100%). However, API 20E had the lowest sensitivity (19.42%; 95% CI 12.94-28.10%). Overall, non-automation tools showed sensitivity of 88.34% (95% CI 77.30-96.25%) and specificity of 90.76% (95% CI 78.45-98.57%)., Conclusion: The study underscores automation's crucial role in accurately identifying B. pseudomallei, supporting evidence-based melioidosis management decisions. Automation technologies, especially those with updating databases, provide reliable and efficient identification., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Malaria, a severe health threat, significantly affects total antioxidant status (TAS) levels, leading to considerable oxidative stress. This systematic review and meta-analysis aimed to delineate differences in TAS levels between malaria patients and healthy controls, and assess correlations between disease severity and parasite density., Methods: The systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42023448761. A comprehensive literature search was conducted in databases such as Embase, MEDLINE, Journals@Ovid, PubMed, Scopus, ProQuest, and Google Scholar to identify studies reporting data on TAS levels in malaria patients. Data from the included studies were analysed both qualitatively and quantitatively. Differences in TAS levels between malaria patients and controls were pooled using a random effects model, with Hedges' g as the effect size measure., Results: Of 1796 identified records, 20 studies met the inclusion criteria. The qualitative synthesis of these studies revealed a marked decrease in TAS levels in patients with malaria compared to non-malaria cases. The meta-analysis results showed a significant decrease in TAS levels in patients with malaria compared to non-malaria cases (P < 0.01, Hedges' g: - 2.75, 95% CI - 3.72 to -1.78, I 2 : 98.16%, 13 studies), suggesting elevated oxidative stress in these patients. Subgroup analyses revealed that TAS level variations were significantly influenced by geographical region, age group, Plasmodium species, and method for measuring TAS. Notably, TAS levels were significantly lower in severe malaria cases and those with high parasite density, indicating a potential relationship between oxidative stress and disease severity., Conclusion: This study highlights the potential utility of TAS as a biomarker for disease risk and severity in malaria. The significant decrease in TAS levels in malaria patients compared to controls implies increased oxidative stress. Further well-designed, large-scale studies are warranted to validate these findings and elucidate the intricate mechanisms linking TAS and malaria., (© 2024. The Author(s).)

Aims: The evidence of superoxide dismutase (SOD) in the pathogenesis of malaria is inconsistent. This study aimed to synthesize the evidence of blood levels of SOD in patients with malaria and determine the association of blood levels of SOD with the severity of malaria. Results: A total of 1874 articles were retrieved from database searches and 28 studies were included in the review. The blood levels of SOD were lower in individuals with malaria compared with those without malaria infection ( p  < 0.01, Cohen's d: -2.06, 95% CI: -2.99 to -1.14), I 2 : 98.96%, 2181 malaria cases/1186 uninfected cases). There were no differences in blood levels of SOD between severe and nonsevere malaria patients ( p  = 0.09, Cohen's d: -1.57, 95% CI: -3.39 to 0.26), I 2 : 96.02%, 69 severe malaria cases/256 nonsevere malaria cases). Innovation and Conclusion: The blood levels of SOD were lower in malaria patients compared with those without malaria infection. Further studies will be required to determine the extent to which SOD might prevent Plasmodium infections during pregnancy. Antioxid. Redox Signal . 40, 222-235.

Background and Aim: Burkholderia pseudomallei , a highly pathogenic bacterium responsible for melioidosis, exhibits ecological ubiquity and thrives within soil and water reservoirs, posing significant infection risks to humans and animals through direct contact. The aim of this study was to elucidate the genetic diversity and prevalence patterns of B. pseudomallei sequence types (STs) across a global spectrum and to understand the relationships between strains isolated from different sources., Materials and Methods: We performed a systematic review and meta-analysis in this study. Extensive research was carried out across three comprehensive databases, including PubMed, Scopus, and ScienceDirect with data collected from 1924 to 2023., Results: A total of 40 carefully selected articles contributed 2737 B. pseudomallei isolates attributed to 729 distinct STs and were incorporated into the systematic review. Among these, ST46 emerged as the most prominent, featuring in 35% of the articles and demonstrating a dominant prevalence, particularly within Southeast Asia. Moreover, ST51 consistently appeared across human, animal, and environmental studies. Subsequently, we performed a meta-analysis, focusing on nine specific STs: ST46, ST51, ST54, ST70, ST84, ST109, ST289, ST325, and ST376. Surprisingly, no statistically significant differences in their pooled prevalence proportions were observed across these compartments for ST46, ST70, ST289, ST325, and ST376 (all p > 0.69). Conversely, the remaining STs, including ST51, ST54, ST84, and ST109, displayed notable variations in their prevalence among the three domains (all p < 0.04). Notably, the pooled prevalence of ST51 in animals and environmental samples surpassed that found in human isolates (p < 0.01)., Conclusion: To the best of our knowledge, this study is the first systematic review and meta-analysis to investigate the intricate relationships between STs and their sources and contributes significantly to our understanding of B. pseudomallei diversity within the One Health framework., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Laklaeng, et al.)

The roles of interleukin-8 (IL-8) in malaria are inconsistent and unclear. This study synthesised evidence for differences in IL-8 levels in patients with malaria of various levels of severity. Relevant studies were searched in Scopus, MEDLINE, Embase, CENTRAL and PubMed from inception to 22 April 2022. Pooled mean differences (MDs) and 95% confidence intervals (CIs) were estimated using the random effects model. Of 1083 articles retrieved from the databases, 34 were included for syntheses. The meta-analysis revealed increased IL-8 levels in individuals with uncomplicated malaria compared with those without malaria (P = 0.04; MD, 25.57 pg/mL; 95% CI, 1.70 to 49.43 pg/mL; I 2 , 99.53, 4 studies; 400 uncomplicated malaria, 204 uninfected controls). The meta-analysis revealed comparable levels of IL-8 between the two groups (P = 0.10; MD, 74.46 pg/mL; 95% CI, -15.08 to 164.0 pg/mL; I 2 , 9.03; 4 studies; 133 severe malaria cases, 568 uncomplicated malaria cases). The study found evidence of increased IL-8 levels in individuals with malaria compared with those without malaria. However, no differences were found in IL-8 levels between patients with severe and non-severe malaria. Further research is needed to investigate the IL-8 cytokine levels in patients with malaria of different levels of severity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Several studies have evaluated the relationship between malondialdehyde (MDA) concentrations and Plasmodium infections; however, the findings remain inconclusive. This study synthesized differences in MDA concentrations among patients with different levels of clinical severity, uninfected controls, and different Plasmodium species. The research protocol was registered in PROSPERO (CRD42023393540). Systematic literature searches for relevant studies were performed using the Embase, MEDLINE, Ovid, ProQuest, PubMed, Scopus, and Google Scholar databases. Qualitative and quantitative syntheses (meta-analyses) of distinct MDA concentrations between the disease groups were performed. Twenty-three studies met the eligibility criteria and were included in the systematic review. Overall, MDA concentrations were significantly elevated in participants with malaria relative to uninfected controls ( p < 0.01, Cohen d: 2.51, 95% confidence interval (CI): 1.88-3.14, I 2 : 96.22%, 14 studies). Increased MDA concentrations in participants with malaria compared with uninfected controls were found in studies that enrolled patients with P. falciparum malaria ( p < 0.01, Cohen d: 2.50, 95% CI: 1.90-3.10, I 2 : 89.7%, 7 studies) and P. vivax malaria ( p < 0.01, Cohen d: 3.70, 95% CI: 2.48-4.92, I 2 : 90.11%, 3 studies). Our findings confirm that MDA concentrations increase during Plasmodium infection, indicating a rise in oxidative stress and lipid peroxidation. Thus, MDA levels can be a valuable biomarker for evaluating these processes in individuals with malaria. However, further research is necessary to fully elucidate the intricate relationship between malaria, antioxidants, oxidative stress, and the specific role of MDA in the progression of malaria.

Zinc supplementation has been explored as a potential intervention to reduce the risk of malaria parasitaemia in randomised controlled trials (RCTs). However, inconsistent evidence has been obtained regarding the efficacy of zinc supplementation in the context of malaria prevention. This systematic review was implemented to survey the existing literature to determine the effects of the daily oral administration of zinc, either alone or in combination with other nutrient supplements, on the risk of malaria parasitaemia. The systematic review was prospectively registered in the PROSPERO database CRD42023424345 and followed PRISMA protocols. A comprehensive search was conducted across multiple databases, including Embase, MEDLINE, Ovid, PubMed, Scopus, ProQuest, and Google Scholar, from their inception until 6 May 2023. The risk of bias in RCTs was assessed using the Cochrane Risk of Bias Tool 2 (RoB 2). The effect sizes, represented as risk ratios (RRs) with 95% confidence intervals (CIs), were standardised by transforming them into log RRs and then pooling them using a fixed-effects or random-effects model depending on the heterogeneity across studies. Comparisons were made between individuals who received zinc alone or zinc in combination with other micronutrient supplements and those who did not receive zinc. A total of 1339 articles were identified through the database searches, and after the screening and selection process, 10 studies were included in the final synthesis. The meta-analysis revealed that zinc supplementation alone did not significantly affect the risk of malaria parasitaemia compared with placebo ( p = 0.30, log RR = 0.05, 95% CI: -0.05-0.15, I 2 = 0.00%, with 566 malaria cases in the zinc intake group and 521 malaria cases in the placebo group). However, the analysis demonstrated a borderline significant effect of zinc supplementation in combination with other micronutrients on the risk of malaria parasitaemia compared with placebo ( p = 0.05, log RR = 1.31, 95% CI: 0.03-2.59, I 2 = 99.22%, with 8904 malaria cases in the zinc intake group and 522 malaria cases in the placebo group). The findings of this systematic review indicate that zinc supplementation, either alone or combined with the supplementation of other micronutrients such as vitamin A, iron, or multiple nutrients, does not significantly alter the risk of malaria parasitaemia. Further research with larger sample sizes is warranted to explore the potential effects of multi-nutrient supplementation and to identify more specific micronutrients and additional factors associated with the risk of malaria, rather than just zinc alone, among individuals in different malaria-endemic areas.

Background: Few data exist on the distinct cytokine profiles of individuals with malaria coinfections and other diseases. This study focuses on data collation of distinct cytokine profiles between individuals with malaria coinfections and monoinfections to provide evidence for further diagnostic or prognostic studies., Methods: We searched five medical databases, including Embase, MEDLINE, PubMed, Ovid, and Scopus, for articles on cytokines in malaria coinfections published from January 1, 1983 to May 3, 2022, after which the distinct cytokine patterns between malaria coinfection and monoinfection were illustrated in heat maps., Results: Preliminary searches identified 2127 articles, of which 34 were included in the systematic review. Distinct cytokine profiles in malaria coinfections with bacteremia; HIV; HBV; dengue; filariasis; intestinal parasites; and schistosomiasis were tumor necrosis factor (TNF), interferon (IFN)-γ, IFN-α, interleukin (IL)-1, IL-1 receptor antagonist (Ra), IL-4, IL-7, IL-12, IL-15, IL-17; TNF, IL-1Ra, IL-4, IL-10, IL-12, IL-18, CCL3, CCL5, CXCL8, CXCL9, CXCL11, granulocyte colony-stimulating factor (G-CSF); TNF, IFN-γ, IL-4, IL-6, IL-10, IL-12, CCL2; IFN-γ, IL-1, IL-4, IL-6, IL-10, IL-12, IL-13, IL-17, CCL2, CCL3, CCL4, G-CSF; IL-1Ra, IL-10, CXCL5, CXCL8, CXCL10; TNF, IL-2, IL-4, IL-6, IL-10; and TNF, IFN-γ, IL-4, IL-5, IL-10, transforming growth factor-β, CXCL8, respectively., Conclusion: This systematic review provides information on distinct cytokine profiles of malaria coinfections and malaria monoinfections. Further studies should investigate whether specific cytokines for each coinfection type could serve as essential diagnostic or prognostic biomarkers for malaria coinfections., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Kotepui et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Interferon (IFN)-γ contributes to the pathogenesis of severe malaria; however, its mechanism remains unclear. Herein, differences in IFN-γ levels between patients with severe and uncomplicated malaria were evaluated using qualitative and quantitative (meta-analysis) approaches. The systematic review protocol was registered at PROSPERO (ID: CRD42022315213). The searches for relevant studies were performed in five databases, including PubMed, Scopus, Embase, MEDLINE and Web of Science, between 1 January and 10 July 2022. A meta-analysis was conducted to pool the mean difference (MD) of IFN-γ levels between patients with severe malaria and those with uncomplicated malaria using a random-effects model (DerSimonian and Laird method). Overall, qualitative synthesis indicated that most studies (14, 58.3%) reported no statistically significant difference in IFN-γ levels between patients with severe malaria and those with uncomplicated malaria. Meanwhile, remaining studies (9, 37.5%) reported that IFN-γ levels were significantly higher in patients with severe malaria than those in patients with uncomplicated malaria. Only one study (4.17%) reported that IFN-γ levels were significantly lower in patients with severe malaria than those in patients with uncomplicated malaria. The meta-analysis results indicated that patients with severe malaria had higher mean IFN-γ levels than those with uncomplicated malaria (p < 0.001, MD: 13.63 pg/mL, 95% confidence interval: 6.98-20.29 pg/mL, I 2 : 99.02%, 14 studies/15 study sites, 652 severe cases/1096 uncomplicated cases). In summary, patients with severe malaria exhibited higher IFN-γ levels than those with uncomplicated malaria, although the heterogeneity of the outcomes is yet to be elucidated. To confirm whether alteration in IFN-γ levels of patients with malaria may indicate disease severity and/or poor prognosis, further studies are warranted., (© 2022. The Author(s).)

Background: Malaria and filariasis are significant vector-borne diseases that are co-endemic in the same human populations. This study aims to collate the evidence, probability, and characteristics of malaria and filariasis co-infections in participants among studies reporting the co-occurrence of both diseases., Methods: We searched for potentially relevant articles reporting the co-occurrence of malaria and filariasis in five electronic databases (Embase, PubMed, Scopus, Medline, and CENTRAL) from inception to May 22, 2022. We estimated the pooled prevalence and probability of malaria and filariasis co-infections among study participants using random-effects meta-analyses and synthesized the characteristics of patients with co-infections narratively., Results: We identified 951 articles, 24 of which (96,838 participants) met eligibility criteria and were included in the systematic review. Results of the meta-analysis showed a pooled prevalence of malaria and filariasis co-infections among participants of 11%. The prevalence of co-infections was 2.3% in Africa, 0.2% in Asia, and 1.6% in South America. The pooled prevalences of malaria and Wuchereria bancrofti, malaria and Loa loa, malaria and Mansonella perstans co-infections were 0.7%, 1.2%, and 1.0%, respectively. The meta-analysis results showed that the co-infections between two parasites occurred by probability (P = 0.001). Patients with co-infections were at increased risk of having an enlarged spleen, a lower rate of severe anemia, lower parasite density, and more asymptomatic clinical status. Patients with co-infections had decreased levels of C-X-C motif chemokine 5, tumor necrosis factor-α, interleukin-4, c4 complement, and interleukin-10. In addition, patients with co-infections had a lower interleukin-10/tumor necrosis factor-α ratio and higher interleukin-10/interleukin-6 ratio., Conclusion: The present study showed that the prevalence of malaria and filariasis co-infections was low and varied between geographical areas in the selected articles. Co-infections tended to occur with a low probability. Further studies investigating the outcomes and characteristics of co-infections are needed., Competing Interests: The authors have declared that no competing interests exist.

Malaria and pneumonia are the leading causes of childhood mortality in children under 5 years of age. Nevertheless, the proportions and deaths of malaria co-infection among patients with severe pneumonia, particularly in children under 5 years of age, and characteristics of co-infection remain poorly explored. Hence, the present study aimed to collate the evidence of malaria among patients with severe pneumonia, severe pneumonia among patients with malaria, and the proportion of deaths among patients with co-infections. Potentially relevant studies were searched in six databases including PubMed, Scopus, Web of Science, Embase, Ovid, and MEDLINE to identify studies on malaria and severe pneumonia co-infections that were published until 21 July 2022 with a restriction for the non-English language but no restriction for the publication year. The quality of the included studies was determined using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). The pooled estimates, including the pooled proportion of malaria among patients with severe pneumonia, and the proportion of deaths among patients with co-infections, were estimated by the random-effects model. Of the 4094 studies examined, 11 studies that met the eligibility criteria were included in the review. Meta-analysis results showed that the proportion of malaria (2162 cases) among patients with severe pneumonia (9738 cases) was 19% (95% CI 12-26%, I 2 : 98.79%, 11 studies). The proportion of severe pneumonia (546 cases) among patients with malaria (10,325 cases) was 20% (95% CI 0-40%, I 2 : 99.48%, 4 studies). The proportion of deaths among patients with co-infection was 13% (95% CI 2-23%, I 2 : 85.1%, 3 studies). In conclusion, nearly one-fifth of patients with severe pneumonia have malaria, one-fifth of patients with malaria have severe pneumonia, and about 13% of co-infections lead to deaths. This information raised the clinical importance of diagnosis and management of concurrent infections. Patients with severe pneumonia should be investigated for malaria, and vice versa. Detection of co-infections might provide the information to inform the physician to manage and cure co-infected patients who live in areas where both diseases were endemic., (© 2022. The Author(s).)

Comprehensive data on the relative contribution of bacteremia to malaria outcomes in a large number of participants are lacking. Therefore, we collated data on the co-existence of malaria and bacteremia in the literature to provide evidence-based information for future studies investigating the clinical significance of this co-infection. The study protocol was registered at PROSPERO (ID: CRD42021287971). Relevant studies were identified from PubMed, Web of Science, and Scopus. The pooled prevalence of (1) co-existent malaria and bacteremia among febrile patients, (2) the pooled prevalence of bacteremia among patients with malaria, (3) the probability of co-infection, and (4) the pooled prevalence of deaths were estimated by the random-effects model. Fifty-one studies involving 1583 cases of co-infection were included in the analyses. Typhoidal Salmonella spp. and Staphylococcus aureus were the most common Gram-negative and Gram-positive bacteria, respectively. The prevalence of co-existent malaria and bacteremia among febrile patients was 1.9% (95% confidence interval (CI) = 1.5-2.2%, I 2 = 96.64%, 31 studies). The prevalence of bacteremia among patients with malaria was 7.6% (95% CI = 6.7-8.7%, and I 2 = 96.68%, 43 studies). Co-infection by malaria and bacteremia did not occur by chance ( p = 0.024, odds ratio = 0.64, 95% CI = 0.43-0.94, and I 2 = 95.7%, 29 studies). The pooled prevalence of deaths among patients with co-infection was 15.0% (95% CI = 8.0-23.0%, I 2 = 75.23%, 8 studies). On the basis of this study, we conclude that although the prevalence of co-infection was low, patients with malaria appear at greater risk of bacteremia and death.

Procalcitonin (PCT), as a marker of malaria severity, remains to be investigated. The present study collated and compared the levels of PCT between patients with severe malaria, uncomplicated malaria, and control participants to assess their role in predicting malaria infection and disease severity. The systematic review was registered at PROSPERO with registration number CRD42021297243. The search for relevant studies that reported PCT in patients with malaria was performed in PubMed, Scopus, and Web of Science. The following meta-analyses were conducted; (1) the pooled mean PCT levels in patients with severe and uncomplicated malaria, and (2) the pooled mean difference in PCT levels between patients with severe and uncomplicated malaria. Fifteen studies were included for qualitative and quantitative syntheses. The meta-analysis results show that the pooled mean PCT levels in patients with uncomplicated malaria were 3.92 ng/mL (95% CI: 2.26-5.58 ng/mL, I 2 : 96.5, five studies), whereas the pooled mean PCT levels in patients with severe malaria were 14.13 ng/mL (95% CI: 8.75-19.5 ng/mL, I 2 : 92.6, six studies). The meta-analysis showed that patients with severe malaria had an equal mean of PCT compared to those with uncomplicated malaria when the random-effects model was used ( p : 0.055, weighted mean difference: 6.93, 95% CI: -0.16-14.02, I 2 : 84.6%, four studies). There were probable correlations between the level of parasitemia, immunity level, and possibly bacterial or other parasitic co-infection that could affect the PCT level among different clinical severities of malaria. Therefore, the PCT level alone does not seem to be a suitable biomarker to discriminate the severe/uncomplicated or infected/uninfected cases. Further studies should investigate the increased PCT levels in combination with other markers in association with malaria infection and severity.

Background and Aim: Escherichia coli O157:H7 is enterohemorrhagic E. coli , which produces verocytotoxin or Shiga toxin. It is a well-known cause of severe diseases in humans worldwide. Cattle and other ruminants are the main reservoirs of this organism. Sports animals, such as fighting bulls, riding horses, and fighting cocks, are economic animals in Southern Thailand. This study aimed to identify E. coli O157:H7 from the rectal swabs of these sports animals and determine the antimicrobial susceptibility patterns of isolated bacteria., Materials and Methods: The rectal swabs were collected from 34 fighting bulls, 32 riding horses, and 31 fighting cocks. The swabs were cultured on MacConkey (MAC) Agar; the suspected colonies were then identified by VITEK ® 2 GN card, and the antimicrobial susceptibility was tested by VITEK ® 2 AST N194 in VITEK ® 2 Compact automation. Escherichia coli O157:H7 was confirmed by culturing on sorbitol MAC agar, the ability to grow at 44°C, and the presence of H7 antigen. In addition, the eaeA ( E. coli attaching and effacing), along with stx1 and stx2 (Shiga cytotoxins) genes, were determined using polymerase chain reaction. Finally, the cytotoxicity of Shiga toxin was confirmed using the Vero cytotoxicity test., Results: Fifty-five suspected isolates (56.70%), which were collected from 19 fighting bulls (55.88%), 13 riding horses (40.63%), and 23 fighting cocks (71.13%), were identified as E. coli . However, one sample (Bull H9/1) from fighting bulls had an equal confidence level (50%) for E. coli and E. coli O157. The confirmation of this isolate demonstrated that it was sorbitol non-fermenter, could assimilate L-lactate, was unable to grow well at 44°C, and reacted with anti-serum to H7 antigen. In addition, it was positive with stx2 and eaeA genes, and the toxin affected Vero cells by a dose-dependent response. The antimicrobial susceptibility test revealed that five out of 55 (9.09%) E. coli isolates were resistant to antimicrobial agents. All five isolates (21.74%) were collected from fighting cocks. Escherichia coli Cock H4/3 was only one of the five isolates resistant to three antimicrobial agents (ciprofloxacin, moxifloxacin, and trimethoprim/sulfamethoxazole). Fortunately, it was not multidrug-resistant bacteria., Conclusion: This is the first report on detection of E. coli O157:H7 in fighting bulls and antibiotic-resistant characteristic of E. coli in fighting cocks in Southern Thailand. This research is beneficial in preventing the dissemination of E. coli O157:H7 or antimicrobial agent-resistant E. coli in sports animals and humans., Competing Interests: The authors declare that they have no competing interests., (Copyright: © Songsri, et al.)

Background: There are limited data regarding prevalence, anti-malarial chemoprophylaxis, and causes of death for severe imported malaria. Thus, we conducted a systematic review and meta-analysis to characterise these variables., Methods: We searched studies reporting deaths attributable to severe imported malaria. The following pooled prevalence rates were determined: 1) the pooled prevalence of severe malaria among patients with imported malaria, 2) the pooled prevalence of deaths among patients with severe imported malaria, 3) the pooled prevalence of anti-malarial chemoprophylaxis among patients with severe imported malaria, and 4) the causes of death among patients with severe imported malaria., Results: The search identified 52 studies that were mainly conducted in Europe (25, 48.1%), North America (16, 30.8%) and Asia (7, 13.5%). The pooled prevalence of severe imported malaria was 12.5% (95% confidence interval [CI] = 10.3%-14.6%, I 2  = 99.32%, 12393 severe cases/118325 imported cases). The pooled prevalence of deaths attributable to severe imported malaria was 5.1% (95% CI = 4.0%-6.2%, I 2  = 91.72%, 721 deaths/16310 severe cases). The pooled prevalence of adequate anti-malarial chemoprophylaxis among patients with severe imported malaria was 9.7% (95% CI = 6.5%-13.0%, I 2  = 89.9%, 203/2049 cases). The most common cause of death was multi-organ failure (12.3%)., Conclusion: The results highlighted the need for education and preventative measures for travellers, immigrants, or workers who plan to visit malaria-endemic areas to minimize the risk of severe disease or death., Competing Interests: Declaration of competing interest All authors declare that there is no conflict of interest., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The entomological inoculation rate (EIR) is one of the key indices used to evaluate malaria transmission and vector control interventions. One of the components of the EIR is the sporozoite rate in Anopheles vectors. A systematic review and meta-analysis was performed to identify the prevalence of Plasmodium spp. in field-collected Anopheles species across Thailand., Methods: This systematic review was registered under the PROSPERO number CRD42021297255. Studies that focused on the identification of Plasmodium spp. in Anopheles mosquitoes were identified from the electronic databases PubMed, Web of Science, and Scopus. The quality of the identified studies was determined using the Strengthening the Reporting of Observational Studies in Epidemiology approach. The proportion of Anopheles mosquitoes collected, Anopheles vectors for Plasmodium species, and specificity of Anopheles vectors for Plasmodium species were analyzed. The pooled prevalence of Plasmodium species among the primary vectors (Anopheles dirus, Anopheles minimus, and Anopheles maculatus) was estimated using the random-effects model., Results: Of the 1113 studies identified, 31 were included in the syntheses. Of the 100,910 Anopheles mosquitoes identified for species and sibling species, An. minimus (40.16%), An. maculatus (16.59%), and Anopheles epiroticus (9.18%) were the most prevalent Anopheles species. Of the 123,286 Anopheles mosquitoes identified, 566 (0.46%) were positive for Plasmodium species. The highest proportions of Plasmodium species were identified in Anopheles hodgkini (2/6, 33.3%), Anopheles nigerrimus (2/24, 8.33%), Anopheles balabacensis (4/84, 4.76%), An. dirus (114/4956, 2.3%), Anopheles annularis (16/852, 1.88%), Anopheles kochi (8/519, 1.54%), Anopheles vagus (3/215, 1.4%), and Anopheles baimaii (1/86, 1.16%). The pooled prevalence of Plasmodium species identified in the main Anopheles vectors was 0.4% of that of Plasmodium species identified in An. dirus was 2.1%, that of Plasmodium species identified in An. minimus was 0.4%, and that of Plasmodium species identified in An. maculatus was 0.4%., Conclusions: We found a low prevalence of Plasmodium infection in Anopheles mosquitoes across Thailand. Therefore, the use of EIR to determine the impact of vector control intervention on malaria parasite transmission and elimination in Thailand must be undertaken with caution, as a large number of Anopheles specimens may be required., (© 2022. The Author(s).)

Malaria and influenza are co-endemic in several geographical areas, and differentiation of their clinical features is difficult. The present study aimed to qualitatively and quantitatively analyze the prevalence and characteristics of malaria and influenza co-infection in febrile patients. The systematic review was registered at PROSPERO (CRD42021264525). Relevant literature that reported malaria and influenza co-infection in febrile patients were searched in PubMed, Web of Science, and Scopus from 20 June to 27 June 2021 and the risk of bias for each study was assessed. Quantitative analysis included pooled prevalence, and the odds of malaria and influenza virus co-infection among febrile patients were estimated using a random-effects model. Subgroup analyses were performed to summarize the effect estimate for each group. Funnel plot, Egger's test, and contour-enhanced funnel plot were used to demonstrate any publication bias among outcomes of included studies. Among 4253 studies retrieved, 10 studies that enrolled 22,066 febrile patients with 650 co-infected patients were included for qualitative and quantitative syntheses. The pooled prevalence of malaria and influenza virus co-infection among febrile patients was 31.0% in Nigeria, 1.0% in Tanzania, 1.0% in Uganda, 1.0% in Malawi, 1.0% in Ghana, 0% in Cambodia, 7.0% in the Central African Republic, and 7.0% in Kenya. Meta-analysis also showed co-infection occurrence by chance ( p = 0.097, odds ratio 0.54, 95% CI 0.26-1.12, I 2 94.9%). The prevalence of malaria and influenza virus co-infection among febrile patients was heterogeneous by country, characteristics of febrile participants, and diagnostic tests for influenza virus. Further studies should investigate severe clinical manifestations or differentiate clinical outcomes between mono-infected or co-infected individuals, whether the co-infection leads to severe disease outcome.

Background: Tumour necrosis factor-alpha (TNF-α) levels are reportedly altered during malaria. In this systematic review and meta-analysis, we aimed to collect and compare data on TNF-α levels between patients with malaria of varying severity and healthy asymptomatic positive controls., Methods: We searched PubMed, Scopus and Web of Science for studies that reported TNF-α levels in malaria cases of different severity and healthy asymptomatic positive controls using a combination of search terms. The quality of the included studies was assessed using the Strengthening the Reporting of Observational Studies in Epidemiology checklist. To compare the TNF-α levels among fatal cases, severe cases, uncomplicated cases and healthy asymptomatic positive controls, we applied the random-effects model that assumed the existence of variations between studies. The effect estimate was pooled mean difference (MD) with a 95% confidence interval (CI)., Results: From 1694 studies, we included 31 studies that met our eligibility criteria for systematic review and meta-analysis. Patients with severe malaria showed higher mean TNF-α levels than those with uncomplicated malaria (P < 0.001, pooled MD = 79.02 pg/ml, 95% CI: 63.68-94.35 pg/ml, I2: 99.5%, n = 26 studies). Furthermore, fatal cases had no difference in the mean TNF-α levels in comparison with survived cases (P = 0.055, pooled MD = 82.38 pg/ml, 95% CI: -1.93 to 166.69 pg/ml, I2: 99.54%, n = 5 studies). Finally, patients with uncomplicated malaria showed higher mean TNF-α levels than those with asymptomatic malaria (P < 0.001, pooled MD = 45.10 pg/ml, 95% CI: 18.45-71.76 pg/ml, I2: 97.09%, n = 5 studies)., Conclusion: This systematic review and meta-analysis confirmed the increase of TNF-α levels in patients with severe malaria. Therefore, TNF-α may be alternatively used as a prognostic biomarker of severe malaria., Trial Registration: Not applicable., (© The Author(s) 2022. Published by Oxford University Press on behalf of International Society of Travel Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Interleukin-6 (IL-6) is generated by immune cells during infection with malaria parasites and they are associated with the immunopathogenesis of malaria. The present systematic review and meta-analysis aimed to compare the differences in IL-6 levels between several groups of patients with malaria and healthy control groups. The systematic review was registered at PROSPERO with a registration number: CRD42021290753. Systematic literature searches were conducted in PubMed, Web of Science, and Scopus until November 7, 2021 to obtain studies that documented IL-6 levels in patients with malaria. The quality of the included studies was assessed using critical appraisal tools from the Joanna Briggs Institute. Differences in the mean IL-6 levels among patients with: (1) severe and non-severe malaria, (2) uncomplicated malaria and controls, (3) uncomplicated and asymptomatic malaria, (4) asymptomatic malaria and healthy controls, and (5) those that died or survived were estimated using a random-effects model. Forty-three of 1,969 studies were included in the systematic review. Results of the meta-analysis showed that patients with severe malaria had higher mean IL-6 levels than those with non-severe malaria [P = 0.04, weight mean difference (WMD) = 96.63 pg/mL, 95% confidence interval (CI) = 0.88 - 19.38 pg/mL, I 2  = 99.9%, 13 studies]. Patients with uncomplicated malaria had higher mean IL-6 levels than the controls (P < 0.001, WMD = 42.86 pg/mL, 95% CI = 30.17 - 55.56 pg/mL, I 2  = 100%, 17 studies). No differences in the mean levels of IL-6 were found between patients with uncomplicated malaria and those with asymptomatic malaria (P = 0.063, WMD = 42.07 pg/mL, 95% CI =  - 2.23 pg/mL to - 86.37 pg/mL, I 2  = 99.1%, 8 studies), or between patients with asymptomatic malaria and healthy controls (P = 0.45, WMD = 1.67 pg/mL, 95% CI =  - 2.73 pg/mL to - 6.07 pg/mL, I 2  = 98.1%, 2 studies). A higher mean level of IL-6 was observed in patients who died compared with the levels of those who survived (P = 0.007, WMD = 1,399.19 pg/mL, 95% CI = 384.16 - 2,414.2 pg/mL, I 2  = 93.1%, 4 studies). Our meta-analysis of the pooled evidence can be used to guide future studies in which IL-6 levels are measured during malaria outbreaks to monitor malaria severity. Heterogeneity of the effect estimate among the included studies was the main limitation of this analysis. In conclusion, significantly increased levels of IL-6 were observed in patients with severe malaria compared with those in patients with non-severe malaria, which indicates that IL-6 is a candidate marker for severe malaria. Future studies should investigate the sensitivity and specificity of increased IL-6 levels to determine the effectiveness of assessments of IL-6 levels monitoring of malaria infection and severity., (© 2022. The Author(s).)

Understanding the prevalence of signs of severity identified in the Thai population with malaria could aid clinical management and disease control efforts, decrease mortality, and promote malaria elimination in Thailand. This systematic review aimed to collate the evidence regarding signs of severity identified in the Thai population with malaria. MEDLINE, Web of Science, and Scopus were searched for potentially relevant studies. The quality of the included studies was assessed using the Joanna Briggs Institute critical appraisal tools. The pooled prevalence of signs of severity among patients with severe malaria and the pooled proportion of each sign of severity among all signs of severity were estimated using random-effects models. Heterogeneity among included studies was assessed using Cochran's Q test. A subgroup analysis was performed to evaluate whether differences in pooled estimates between different study sites. Publication bias was assessed by visualizing funnel plot asymmetry and using Egger's test. Among 741 studies identified by literature searching, 12 studies of a total of 2900 patients with severe malaria, in 7 Thai hospitals, met the eligibility criteria. Results of meta-analyses showed that the signs of the severity of malaria with the highest prevalence in Thailand were jaundice (54%), hyperparasitemia (47%), impaired consciousness/coma (21%), acidosis (18%), renal impairment (13%), shock (10%), convulsions (9%), severe anemia (8%), pulmonary edema/acute respiratory distress syndrome (ARDS) (8%), hypoglycemia (4%), and bleeding/disseminated intravascular coagulation (DIC) (2%). The signs of the severity of malaria that made up the highest proportion of all signs of severity identified in the Thai population with malaria were hyperparasitemia (33%), jaundice (33%), impaired consciousness/coma (12%), acidosis (9%), renal impairment (7%), severe anemia (6%), convulsions (5%), shock (5%), pulmonary edema/ARDS (3%), bleeding/DIC (1%), and hypoglycemia (1%). The present study revealed the prevalence of signs of severity identified in the Thai population with malaria. Jaundice, hyperparasitemia, and impaired consciousness/coma were the most common signs of severity identified. These results may inform the management of patients with severe malaria and promote malaria-elimination efforts in Thailand.

The understanding of platelet biology under physiological and pathological conditions like malaria infection is critical importance in the context of the disease outcome or model systems used. The importance of severe thrombocytopenia (platelet count < 50,000 cells (µL) and profound thrombocytopenia (platelet count < 20,000 cells/µL) in malaria patients remains unclear. This study aimed to synthesize evidence regarding the risks of severe and profound thrombocytopenia in patients with severe non- Plasmodium falciparum malaria. Our overall aim was to identify potential indicators of severe non- P . falciparum malaria and the Plasmodium species that cause severe outcomes. This systematic review was registered at the International Prospective Register of Systematic Reviews (PROSPERO) under registration ID CRD42020196541. Studies were identified from previous systematic reviews ( n = 5) and the MEDLINE, Scopus, and Web of Science databases from 9 June 2019 to 9 June 2020. Studies were included if they reported the outcome of severe non-Plasmodium species infection, as defined by the World Health Organization (WHO) criteria, in patients with known platelet counts and/or severe and profound thrombocytopenia. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). Data were pooled, and pooled prevalence (PP) and pooled odds ratios (ORs) were calculated using random effects models. Of the 118 studies identified from previous meta-nalyses, 21 met the inclusion criteria. Of the 4807 studies identified from the databases, three met the inclusion criteria. Nine studies identified from reference lists and other sources also met the inclusion criteria. The results of 33 studies reporting the outcomes of patients with severe P . vivax and P . knowlesi infection were pooled for meta-analysis. The PP of severe thrombocytopenia (reported in 21 studies) was estimated at 47% (95% confidence interval (CI): 33-61%, I 2 : 96.5%), while that of profound thrombocytopenia (reported in 13 studies) was estimated at 20% (95% CI: 14-27%, 85.2%). The pooled weighted mean difference (WMD) in platelet counts between severe uncomplicated Plasmodium infections (reported in 11 studies) was estimated at -28.51% (95% CI: -40.35-61%, I 2 : 97.7%), while the pooled WMD in platelet counts between severe non- Plasmodium and severe P . falciparum infections (reported in eight studies) was estimated at -3.83% (95% CI: -13.90-6.25%, I 2 : 85.2%). The pooled OR for severe/profound thrombocytopenia comparing severe to uncomplicated Plasmodium infection was 2.92 (95% CI: 2.24-3.81, I 2 : 39.9%). The PP of death from severe and profound thrombocytopenia was estimated at 11% (95% CI: 0-22%). These results suggest that individuals with severe non- P . falciparum infection (particularly P . vivax and P . knowlesi ) who exhibit severe or profound thrombocytopenia should be regarded as high risk, and should be treated for severe malaria according to current WHO guidelines. In addition, severe or profound thrombocytopenia coupled with other clinical and microscopic parameters can significantly improve malaria diagnosis, enhance the timely treatment of malaria infections, and reduce the morbidity and mortality of severe non- P . falciparum malaria.

This study investigated whether C-reactive protein (CRP) can be used as a marker for the early detection and monitoring of malaria severity. Potentially relevant studies were searched in Medline (PubMed), Scopus, and Web of Science. Differences in CRP between (1) severe malaria and uncomplicated malaria, (2) uncomplicated malaria and asymptomatic malaria, (3) uncomplicated malaria and febrile/healthy controls, and (4) asymptomatic malaria and febrile/healthy controls were estimated using random-effects models. Twenty-nine studies were included for meta-analysis. The results of meta-analysis demonstrated higher mean CRP levels in (1) patients with severe malaria compared with uncomplicated malaria (p < 0.001, standard mean difference [SMD]: 1.52, 95% confidence interval [CI]: 0.91-2.12, I 2 : 95.1%), (2) patients with uncomplicated malaria than in those with asymptomatic malaria (p: 0.001, SMD: 1.65, 95% CI: 0.67-2.62, I 2 : 96.7%), (3) patients with uncomplicated malaria compared with febrile/healthy controls (p < 0.001, SMD: 2.38, 95% CI: 1.37-3.40, I 2 : 98.5%), and (4) patients with asymptomatic malaria compared with febrile/healthy controls (p < 0.001, SMD: 2.55, 95% CI: 1.60-3.50, I 2 : 99.2%). This study demonstrated CRP levels are a biomarker for the early detection and monitoring of malaria severity., (© 2021. The Author(s).)

The geographical overlaps of malaria parasites and Salmonella spp. can lead to co-infection of these two pathogens, especially in the tropics where malaria is endemic. Moreover, few literatures suggested that malaria infection was associated with Salmonella bacteremia. Therefore, this study quantified pooled prevalence of typhoidal/non-typhoidal Salmonella (NTS) and probability of typhoidal/NTS and malaria co-infection among febrile patients. The systematic review protocol was registered at PROSPERO (CRD42021252322). Studies on co-infection of typhoidal/NTS and malaria were searched in PubMed, Scopus, and Web of Science. The risk of bias of the included studies was assessed using the checklist for analytical cross-sectional studies developed by the Joanna Briggs Institute. Meta-analyses on the following criteria were performed: (1) pooled prevalence of typhoidal/NTS and malaria co-infection among febrile patients, (2) pooled prevalence of typhoidal/NTS among malaria patients, (3) pooled prevalence of malaria infections among patients with Salmonella spp. infection, and (4) probability of typhoidal/NTS and malaria co-infection among febrile patients. Additionally, the case fatality rate and mean difference of malarial parasitemia between typhoidal/NTS and malaria co-infection and Plasmodium monoinfection were also determined. The subgroup analyses of typhoidal/NTS, regions (Africa and Asia), countries, time (publication year), characteristics of participants, and diagnostic tests for identifying Salmonella spp. were also conducted. A sensitivity test was performed to determine the robustness of the study outcomes. Publication bias among the included studies was evaluated using the funnel plot and Egger's test. All analyses were performed using Stata version 15 (StataCorp LLC, Texas, USA) with a p-value < 0.05 indicating statistical significance. Eighty-one studies that met the eligibility criteria were included in the analyses. Of the 73,775 study participants, 4523 had typhoidal/NTS and malaria co-infections. The pooled prevalence rates of typhoidal/NTS and malaria co-infection among febrile patients were 14% (95% confidence interval [CI], 9-19%; I 2 , 99.4%; 2971/17,720 cases) and 1% (95% CI 1-1%; I 2 , 89.9%; 252/29,081 cases) using the Widal test and culture methods for identifying Salmonella spp., respectively. The pooled prevalence rates of typhoidal/NTS infection among patients with malaria were 31% (95% CI 23-39%; I 2 , 99.5%; 3202/19,208 cases) and 3% (95% CI 2-3%; I 2 , 86.8%; 407/40,426 cases) using the Widal test and culture methods for identifying Salmonella spp., respectively. The pooled prevalence rates of malaria infection among patients with typhoidal/NTS were 17% (95% CI 6-29%; I 2 , 33.3%; 13/75 cases) and 43% (95% CI 32-53%; I 2 , 89.1%; 287/736 cases), respectively. Malaria infection was associated with typhoidal/NTS in children aged < 15 years (p < 0.0001; odds ratio, 0.36; 95% CI 0.23-0.58; I 2 , 73.9%; 3188/43,212 cases). The case fatality rate in patients with malaria and NTS co-infections was 16% (95% CI 9-24%; I 2 , 89.1%; 18/103 cases). From the view of the present study, the inappropriate use of the Widal test for Salmonella spp. diagnosis can overestimate the prevalence of typhoidal/NTS and malaria co-infections. Malaria infection associated with typhoidal/NTS in children and the high case fatality rates among few patients with co-infections were highlighted. Future prospective longitudinal studies using the appropriate and confirmatory dsiagnosis for Salmonella spp. infections are highly recommended to ensure the real prevalence of co-infection and highlight the outcome of co-infection for providing adequate treatment in febrile patients who live in areas where malaria is endemic, such as tropical Africa and India., (© 2021. The Author(s).)

Metabolic acidosis in severe malaria usually occurs in the form of lactic acidosis. The present study aimed to collate articles from the literature that have reported blood lactate levels in patients with severe malaria and tested the hypothesis that blood lactate levels are elevated in patients with malaria compared to those with uncomplicated malaria. Moreover, the difference in lactate levels between patients who died and those who survived was estimated using a meta-analytic approach. Potentially relevant studies were searched for in PubMed, Web of Science, and Scopus. The quality of the included studies was assessed using the Jadad scale and strengthening the reporting of observational studies in epidemiology (STROBE). The pooled mean blood lactate in patients with severe malaria, the pooled weighted mean difference (WMD) of blood lactate between patients with severe malaria and those with uncomplicated malaria, and the pooled WMD and 95% CI of blood lactate between patients who died from and those who survived severe malaria were estimated using the random-effects model. Heterogeneity among the outcomes of the included studies was assessed using Cochran's Q and I 2 statistics. A meta-regression analysis was performed to identify the source(s) of heterogeneity of outcomes among the included studies. A subgroup analysis was further performed to separately analyze the outcomes stratified by the probable source(s) of heterogeneity. Publication bias was assessed by the visual inspection of the funnel plot asymmetry. Of 793 studies retrieved from the searches, 30 studies were included in qualitative and quantitative syntheses. The pooled mean lactate in patients with severe malaria was 5.04 mM (95% CI: 4.44-5.64; I 2 : 99.9%; n = 30,202 cases from 30 studies). The mean lactate in patients with severe malaria (1568 cases) was higher than in those with uncomplicated malaria (1693 cases) ( p = 0.003; MD: 2.46; 95% CI: 0.85-4.07; I 2 : 100%; nine studies). The mean lactate in patients with severe malaria who died (272 cases) was higher than in those with severe malaria who survived (1370 cases) ( p < 0.001; MD: 2.74; 95% CI: 1.74-3.75; I 2 : 95.8%; six studies). In conclusion, the present study showed a high mean difference in blood lactate level between patients with severe malaria and patients with uncomplicated malaria. In addition, there was a high mean difference in blood lactate level between patients with severe malaria who died compared to those with severe malaria who survived. Further studies are needed to investigate the prognostic value of blood lactate levels to identify patients who are at high risk of developing severe malaria or dying.

Malaria and leptospirosis are important cosmopolitan infections that have emerged with overlapping geographic distribution, especially in tropical and subtropical regions. Therefore, co-infection with malaria and leptospirosis may occur in overlapping areas. The present study aimed to quantify the prevalence of malaria and leptospirosis co-infection among febrile patients. The association between malaria and leptospirosis infections was also investigated. Relevant studies that had reported malaria and leptospirosis co-infection were identified from PubMed, Scopus, and Web of Science. The risk of bias of the studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Tool. The pooled prevalence of malaria and leptospirosis co-infections among febrile patients and the pooled prevalence of leptospirosis infection among malaria patients were estimated using random effect models. The association between malaria and leptospirosis infection among febrile patients was estimated using random effect models. The outcomes of each study were shown in a forest plot in point estimate and 95% confidence interval (CI). Heterogeneity among the included studies was assessed using Cochran's Q and quantified using I-squared statistics. For leptospirosis, subgroup analyses of countries, diagnostic tests, and participants' age groups were performed to specify prevalence in each subgroup. Publication bias was assessed by funnel-plot visualization. Of the 2370 articles identified from the databases, 15 studies met the eligibility criteria and were included for qualitative and quantitative syntheses. Most of the included studies were conducted in India (5/15, 33.3%), Thailand (3/15, 20%), and Cambodia (2/15, 13.3%). Most of the enrolled cases were febrile patients (5838 cases) and malaria-positive patients (421 cases). The meta-analysis showed that the pooled prevalence of malaria and leptospirosis co-infection (86 cases) among febrile patients was 1% (95% CI: 1-2%, I 2 : 83.3%), while the pooled prevalence of leptospirosis infection (186 cases) among malaria patients was 13% (95% CI: 9-18%, I 2 : 90.3%). The meta-analysis showed that malaria and leptospirosis co-infections occurred by chance (p: 0.434, OR: 1.4, 95% CI: 0.6-3.28, I 2 : 85.2%). The prevalence of malaria in leptospirosis co-infection among febrile patients in the included studies was low. Co-infection was likely to occur by chance. However, as clinical symptoms of leptospirosis patients were non-specific and not distinguishable from symptoms of malaria patients, clinicians caring for febrile patients in an area where those two diseases are endemic should maintain a high index of suspicion for both diseases and whether mono-infections or co-infections are likely. Recognition of this co-infection may play an important role in reducing disease severity and treatment duration.

Co-infection with malaria and chikungunya (CHIKV) could exert a significant public health impact with infection misdiagnosis. Therefore, this study aimed to collect qualitative and quantitative evidence of malaria and CHIKV co-infection among febrile patients. Methods : Potentially relevant studies were identified using PubMed, Web of Science, and Scopus. The bias risk of the included studies was assessed using the checklist for analytical cross-sectional studies developed by the Joanna Briggs Institute. The pooled prevalence of malaria and CHIKV co-infection among febrile patients and the pooled prevalence of CHIKV infection among malaria patients were estimated with the random effect model. The odds of malaria and CHIKV co-infection among febrile patients were also estimated using a random effect model that presumed the heterogeneity of the outcomes of the included studies. The heterogeneity among the included studies was assessed using the Cochran Q test and I 2 statistics. Publication bias was assessed using the funnel plot and Egger's test. Results : Of the 1924 studies that were identified from the three databases, 10 fulfilled the eligibility criteria and were included in our study. The pooled prevalence of malaria and CHIKV co-infection (182 cases) among febrile patients (16,787 cases), stratified by diagnostic tests for CHIKV, was 10% (95% confidence interval (CI): 8-11%, I 2 : 99.5%) using RDT (IgM), 7% (95% CI: 4-10%) using the plaque reduction neutralization test (PRNT), 1% (95% CI: 0-2%, I 2 : 41.5%) using IgM and IgG ELISA, and 4% (95% CI: 2-6%) using real-time RT-PCR. When the prevalence was stratified by country, the prevalence of co-infection was 7% (95% CI: 5-10%, I 2 : 99.5%) in Nigeria, 1% (95% CI: 0-2%, I 2 : 99.5%) in Tanzania, 10% (95% CI: 8-11%) in Sierra Leone, 1% (95% CI: 0-4%) in Mozambique, and 4% (95% CI: 2-6%) in Kenya. The pooled prevalence of CHIKV infection (182 cases) among malaria patients (8317 cases), stratified by diagnostic tests for CHIKV, was 39% (95% CI: 34-44%, I 2 : 99.7%) using RDT (IgM), 43% (95% CI: 30-57%) using PRNT, 5% (95% CI: 3-7%, I 2 : 5.18%) using IgM and IgG ELISA, and 9% (95% CI: 6-15%) using real-time RT-PCR. The meta-analysis showed that malaria and CHIKV co-infection occurred by chance ( p : 0.59, OR: 0.32, 95% CI: 0.6-1.07, I 2 : 78.5%). Conclusions : The prevalence of malaria and CHIKV co-infection varied from 0% to 10% as per the diagnostic test for CHIKV infection or the country where the co-infection was reported. Hence, the clinicians who diagnose patients with malaria infections in areas where two diseases are endemic should further investigate for CHIKV co-infection to prevent misdiagnosis or delayed treatment of concurrent infection.

Burkholderia pseudomallei is a Gram-negative bacterium and the causative agent of melioidosis in humans and animals in the tropics. The clinical manifestations of melioidosis are diverse, ranging from localized infections to whole-body sepsis. The effective serological method is crucial for the point-of-care diagnosis of melioidosis. The aim of this study was to develop indirect immunofluorescence assay (IFA)-based methods for detecting immunoglobulin G (IgG) antibodies in melioidosis patients. These methods use whole-cell antigens made from recombinant E. coli strains that express major B. pseudomallei antigens, including TssM, OmpH, AhpC, BimA, and Hcp1. A total of 271 serum samples from culture-confirmed melioidosis patients ( n = 81), patients with other known infections ( n = 70), and healthy donors ( n = 120) were tested. Our study showed that the recombinant TssM strain had the highest performance, with 92.6% sensitivity, 100% specificity, 100% positive predictive value, 96.9% negative predictive value, 97.8% efficiency, 97.0% accuracy, and no cross-reactivity. The method agreement analysis based on k efficiency calculations showed that all five IFA methods perfectly agreed with the standard culturing method, while the traditional indirect hemagglutination (IHA) method moderately agreed with the culture. In summary, our investigations showed that the TssM-IFA method could be used for melioidosis diagnosis.

Multidrug resistance in V. cholerae has been increasing around the world including northeastern Thailand. The aquatic environment is a reservoir of V. cholerae and might be an important source of resistant strains. The aims of this study were to investigate the phylogenetic relationships of int SXT gene sequences from 31 clinical and 14 environmental V. cholerae O1 and non-O1/non-O139 isolates and 11 sequences amplified directly from environmental water samples. We also amplified class 1 integrons, the SXT elements (targeting the int SXT gene) and antimicrobial resistance genes directly from water samples. Phylogenetic analysis displayed two major distinct clusters (clusters 1 and 2). Most V. cholerae O1 (19/20, 95%) and non-O1/non-O139 isolates (8/11, 72.7%) from clinical sources, and all sequences obtained directly from water samples, belonged to cluster 1. Cluster 2 mostly comprised environmental non-O1/non-O139 isolates (10/12, 83.3%). We successfully amplified the SXT elements directly from17.5% of water samples. Associated resistance genes were also amplified as follows: sul2 (41.3% of water samples), dfrA1 (60%), dfr18 (33.8%), strB (70%) and tetA (2.5%). Class 1 integrons were not found in water samples, indicating that the SXT element was the major contributor of multidrug resistance determinants in this region. The SXT element and antimicrobial resistance genes could be transferred from clinical V. cholerae O1 to environmental V. cholerae non-O1/non-O139 was demonstrated by conjugation experiment. These findings indicate that there may have been cross dissemination and horizontal gene transfer (HGT) of the SXT element harbored by V. cholerae O1 and non-O1/non-O139 strains isolated from clinical and environmental water sources. Environmental water might be an important source of antimicrobial resistance genes in V. cholerae in this region. Direct detection of antimicrobial resistance genes in water samples can be used for monitoring the spread of such genes in the ecosystem., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Emergence of multiple drug resistance in Vibrio cholerae has been increasing around the world including Northeast Thailand. In this study, 92 isolates of V. cholerae (50 O1 and 42 non-O1/non-O139 isolates) from clinical and environmental sources in Northeast Thailand were randomly selected and investigated for the presence of SXT element, class 1 integron and antimicrobial resistance genes. Genotypic-phenotypic concordance of antimicrobial resistance was also determined. Using PCR-based assays, 79% of V. cholerae isolates were positive for SXT element, whereas only 1% was positive for class 1 integron. SXT element harbored antimicrobial resistance genes, dfrA1 or dfr18, floR, strB, sul2, and tetA. Overall phenotypic-genotypic concordance of antimicrobial resistance was 78%, with highest and lowest value being for trimethoprim (83%) and chloramphenicol (70%), respectively. Ninety-two percent of V. cholerae O1 strains isolated from clinical sources harbored both dfrA1 (O1-specific trimethoprim resistance gene) and dfr18 (non-O1-specific trimethoprim resistance gene), whereas only 5% of V. cholerae non-O1/non-O139 strains harbored both genes. All V. cholerae O1 isolated from environmental source harbored dfr18 but 48% of V. cholerae non-O1/non-O139 harbored dfrA1. This study indicates that SXT element was the main contributor to the circulation of multiple-drug resistance determinants in V. cholerae strains in Northeast Thailand and that genetic exchange of SXT element can occur in both V. cholerae O1 and non-O1/non-O139 strains from clinical and environmental sources.

Vibrio parahaemolyticus is responsible for seafood-borne gastroenteritis worldwide. Isolates of V. parahaemolyticus from clinical samples (n=74) and cockles (Anadara granosa) (n=74) in Thailand were analyzed by serotyping, determination of virulence and related marker genes present, response to antimicrobial agents, and genetic relatedness. Serological analysis revealed 31 different serotypes, 10 of which occurred among both clinical and cockle samples. The clinical isolates commonly included the pandemic serogroup O3:K6, while a few of the cockle isolates exhibited likely pandemic serovariants such as O3:KUT and O4:KUT, but not O3:K6. The pandemic (orf8 gene-positive) strains were more frequently found among clinical isolates (78.4%) than cockle isolates (28.4%) (p<0.001). Likewise, the virulence and related marker genes were more commonly detected among clinical than cockle isolates; i.e., tdh gene (93.2% versus 29.7%), vcrD2 (97.3% versus 23.0%), vopB2 (89.2% versus 13.5%), vopT (98.6% versus 36.5%) (all p<0.001) and trh (10.8% versus 1.4%) (p<0.05). Pulsed-field gel electrophoresis of NotI-digested genomic DNA of 41 randomly selected V. parahaemolyticus isolates representing different serotypes produced 33 pulsotypes that formed 5 different clusters (clonal complexes) (A-E) in a dendrogram. Vibrio parahaemolyticus O3:K6 and likely related pandemic serotypes were especially common among the numerous clinical isolates in cluster C, suggesting a close clonal link among many of these isolates. Most clinical and cockle isolates were resistant to ampicillin. This study indicates that O3:K6 and its likely serovariants based on the PFGE clusters, are causative agents. Seafoods such as cockles potentially serve as a source of virulent V. parahaemolyticus, but further work is required to identify possible additional sources., (Copyright © 2016. Published by Elsevier B.V.)

Vibrio vulnificus can cause septicemia, wound infection and gastroenteritis. The most severe infections are related to consumption of raw or undercooked seafood. Virulence genes, biomarkers, antimicrobial resistance, and genetic relationships among V vulnificus isolated from clinical and environmental sources in Thailand have not hitherto been investigated. ViuB encoding vulnibactin siderophore was detected in 33% and 50% of clinical and environmental (cockle) V. vulnificus isolates, respectively, and capsular polysaccharide allele 1 in 67% and 75% of clinical and environmental isolates, respectively. Analysis of the 16 S rDNA gene revealed that type B was the most frequent in both clinical and environmental isolates (67%) whereas the non type-able (30%) was detected only in environmental isolates. The virulence-correlated gene (vcg) with both type C and E together was the most frequently found among the clinical (67%) and environmental (72%) isolates. Pulsed-field gel electrophoresis differentiated V vulnificus into 2 clusters; most cockle samples (83%) and all clinical isolates grouped into cluster II, indicating a possible clonal relationship between V. vulnificus isolated from patients and cockles. Only 20% of environmental isolates were resistant to ampicillin. These studies suggest that V vulnificus isolated from cockles has virulence genes similar to those in clinical isolates and thus may have the potential of causing disease.