Tropical biomedicine最新文献

Escherichia coli (E. coli)-induced community-acquired meningitis in adults is exceedingly rare, with an average of only one annual case reported worldwide. The majority of E. coli meningitis cases in adults are associated with healthcare settings, typically following head injuries or neurosurgical interventions. Nonetheless, spontaneous E. coli meningitis in adults can arise in individuals with various comorbid conditions. This case report details the clinical presentation, diagnostic workup, management, and eventual outcome of a 45-year-old male with significant comorbidities who presented with severe respiratory distress, altered mental status, and generalized tonic-clonic seizure. Subsequently, multiplex PCR analysis of cerebrospinal fluid revealed E. coli K1. Despite aggressive management, including broadspectrum antibiotics, the patient deteriorated and succumbed to his illness. This report contributes to the understanding of E. coli K1 as a lethal pathogen in adult meningitis, emphasizing the need for vigilance in diagnosing and treating this condition.

Chikungunya virus (CHIKV) and Japanese encephalitis virus (JEV) are mosquito-borne arboviruses that pose significant public health risks, especially in tropical regions like Malaysia. CHIKV is linked to joint and muscle pain, while JEV can cause severe neurological illnesses and encephalitis if untreated. With no specific treatments available, research into potential antivirals is crucial. This study investigates the inhibitory potential of resveratrol (RES) against CHIKV and JEV in vitro. Cytotoxicity of RES was assessed on human adenocarcinoma alveolar basal epithelial cells (A549) using the MTS assay, followed by dose-dependent analyses to determine optimal inhibitory concentrations. Antiviral effects were explored through pre-infection, post-infection, virucidal, and anti-adsorption assays, with virus titres measured via plaque and foci-forming assays for CHIKV and JEV, respectively. Results revealed that RES's pre- and post-infection treatments significantly reduced titres of both viruses in a dose-dependent manner. Notably, CHIKV titres were reduced by over 65% (p < 0.01) when treated with 100 µM RES, whether administered pre-infection or post-infection. For JEV, a reduction of over 93% (p < 0.05) was observed only with post-infection treatment, while pre-infection treatment alone did not yield a significant reduction. In addition, both pre-incubation and anti-adsorption assays for CHIKV and JEV showed no significant results. These findings suggest that RES likely inhibits viral replication by modulating host cellular mechanisms rather than directly targeting the viruses. In summary, this study demonstrates that RES exhibits antiviral properties against CHIKV and JEV replication, underscoring its potential as an effective antiviral agent. However, further in vivo studies are needed to fully evaluate its therapeutic potential and efficacy.

Streptococcus sanguinis is a commensal oral flora and an opportunistic pathogen prevalently implicated in native valve infective endocarditis (IE). However, in developing nations, infective endocarditis is currently affecting young healthy adults. In this case report, we presented a case of a 26-year-old male with Streptococcus sanguinis endocarditis without obvious aetiology, which was initially diagnosed and treated for dengue fever. A full medical history, physical examination, procedures such as transoesophageal echocardiography and electrocardiogram, and laboratory tests of full blood count and blood cultures were obtained to diagnose infective endocarditis based on the modified Duke criteria. The patient underwent mitral valve replacement with antibiotic therapy and currently presents no further complications. This article underscores the significance of thorough clinical assessment on patients and the hidden, life-threatening complications of Streptococcus sanguinis infective endocarditis if left untreated.

Tuberculosis (TB), an infectious disease caused by the bacterium Mycobacterium tuberculosis (Mtb), is a major cause of morbidity and mortality worldwide. Annually, millions of new cases of tuberculosis are documented. Research in tuberculosis-immune has hitherto focused predominantly on the role of T cells in Mtb infection. Although there have been studies in progress which have supported the notion that B cells are crucial players in combating infectious diseases, the role of B cells in TB is still not fully understood. There is a paucity of in-depth analysis of various B lymphocyte subpopulations and the understanding of the immunophenotypic changes of the B-cell lineage during tuberculosis infection. Therefore, we aimed to investigate the changes in B lymphocyte subpopulations in mice infected with M.tuberculosis H37Ra. The percentage/frequency of peritoneal B cells (CD45R+), B1b cells (CD45RIntIgDCD5- CD11+), splenic B cells (CD45R+), and splenic marginal zone B (MZ B) cells (CD45R+CD23- CD21hi) decreased (P < 0.05), while the percentage of splenic follicular B (Fo B) cells (CD45R+CD23+ CD21int) and lymph node B cells (CD19+) increased at the 4th and 8th weeks (P < 0.05). It was suggested that H37Ra infection changed the distribution of B lymphocyte subpopulations. In addition, the percentage of CD69+B cells and memory B cells (CD45R+CD27+ IgD+/-) increased in the infected mice at different infection periods (P < 0.05), which suggested H37Ra infection promoted B cell activation and produced a large number of memory B cells. As a conclusion, H37Ra infection can affect the distribution of B lymphocyte subpopulations, with a concomitant down-regulation of MZ B cells, which perform innate immunity, and up-regulation of adaptive immune response cells (Fo B cells and lymph node B cells). Furthermore, it has been demonstrated that H37Ra infection can promote the immune response of B lymphocytes to tuberculosis, through the stimulation of the body to produce a large number of activated and memory B cells.

Sexual mosaicism was found in an adult black fly reared from a pupa in Vietnam. It is considered an antero-posterior type of gynandromorph, showing female phenotype for the head, thorax and wing; male phenotype for the abdomen including the genitalia; and mixed phenotype for the legs. The fly is identified as Simulium (Gomphostilbia) hongthaii in the S. asakoae species-group by having the sensory vesicle medium-long (0.28-0.30 times as long as the third palpal segment), mandible without teeth on its outer margin, and ventral plate transverse, with its lateral margins emarginated basally when viewed ventrally, and trapezoidal, with its ventral margin nearly straight when viewed posteriorly. This specimen represents the first record of a black fly with sexual mosaicism in Vietnam.

As critically ill COVID-19 patients are prone to infections by other respiratory pathogens, this study aimed to investigate the detection of respiratory co-pathogens in such patients, by employing a multiplex respiratory molecular panel. Conducted at Universiti Sains Malaysia Specialist Hospital (HPUSM) from November 1, 2021, to November 1, 2022, this retrospective cross-sectional study analysed adults admitted with confirmed COVID-19. Oropharyngeal/ nasopharyngeal swabs collected upon admission were tested using the Fast Track Diagnostic (FTD®) Respiratory Pathogens 33 multiplex kit to detect other respiratory pathogens. Within 48 hours of admission, the presence and type of organisms were determined to assess community co-infections. Among 48 critically ill COVID-19 patients (26 male; mean age, 62.2 years), clinically significant organisms were found in 32 patients (67%). Bacterial co-infections or co-colonization were detected in 91% (29/32) of these patients, with Klebsiella pneumoniae (40%) and Staphylococcus aureus (23%) were the most common, followed by Streptococcus pneumoniae (11%), Moraxella catarrhalis (4%), and Haemophilus influenzae (2%). Fungal (6%) and viral (2%) co-infections were less frequent. The use of syndromic respiratory panel in critically ill COVID-19 patients offers the advantage of being highly sensitive, rapid, and able to detect multiple pathogens. However, detection of multiple respiratory pathogens needs to be interpreted with caution, taking into consideration patient's clinical and radiological findings, as well as quantitative molecular data.

Leptospirosis, caused by the Leptospira spp., is endemic in humid subtropical and tropical climates. Several environmental settings can harbour the survival of Leptospira; hence, continuous surveillance of the high-risk areas is critical. This study was conducted to detect the presence of Leptospira in wet markets and paddy fields in Penang, Malaysia. A total of 62 soil and water samples were collected aseptically from three wet markets and two paddy fields. The samples were cultured twice on the sampling day and after two weeks of storage in the dark at ambient temperature. All environmental samples and positive cultures were subjected to deoxyribonucleic acid (DNA) extraction and polymerase chain reaction (PCR) targeting 16S rRNA, lipL32 and rrs genes. 16S rRNA-positive samples were further sent for sequencing. Of 62 samples, 21 (21/62, 33.9%) tested positive via culture and PCR. Wet markets significantly had a higher detection rate of leptospires (29%) than paddy fields (4.8%). Four Leptospira species (L. selangorensis, L. dzoumogneensis, L. mtsangambouensis, and L. meyeri) were identified in wet markets and three (L. meyeri, L. wolffii, and L. kmetyi) in paddy fields. Storing the environmental samples for two weeks before isolation yielded a higher positivity (11/14) than culturing samples on the sampling day (6/14). The presence of Leptospira in the environment of wet markets and paddy fields in Penang although primarily intermediate and saprophyte indicates the crucial need to implement preventive measures to prevent the possibility of leptospirosis infection among the workers.

Typhoid is an acute febrile illness primarily caused by Salmonella enterica serotype typhi (S. Typhi) which could be challenging to diagnose in children, owing to its non-specific clinical signs and symptoms which may resemble other febrile illnesses. Here, we present a case of typhoid which was atypically presented as fever of unknown origin (FUO) in a two-year-old boy with underlying glucose-6-phosphate dehydrogenase (G6PD) deficiency. This child was initially diagnosed and managed as acute tonsillopharyngitis, however remained febrile despite medications. A series of investigations were performed and S. Typhi was isolated from the bone marrow culture after almost a month of admission. The antibiotic was started based on antibiotic susceptibility testing and he recovered well. Our case underscores the challenges of diagnosis establishment and clinical management of typhoid in paediatric patients who has underlying disease and emphasizes the importance of having high index of clinical suspicion to ascertain timely and proper diagnosis.

Canine rabies poses a significant global public health threat, including in Malaysia. Despite this disease's severity, there is a notable research gap concerning the spatial and temporal epidemiology of canine rabies, limiting the development of effective control strategies. This study delves into the spatiotemporal patterns of canine rabies occurrence in Sarawak, East Malaysia, spanning from 2017 to 2023, with the primary goal of offering insights crucial for shaping robust control measures. Utilising surveillance data from the World Animal Health Information System (OIE-WAHIS) and local reports, we employed descriptive statistics to analyse the data. Spatial heat maps were generated to pinpoint rabies hotspots and examine their association with potential transmission predictors. Findings unveiled an overall positivity rate of 28.34%, predominantly affecting dogs. District-specific variations emerged, and spatial risk maps successfully identified hotspots. Predictive factors, including dog versus human population and households, exhibited strong positive correlations with rabies occurrences. High-risk regions displayed associations with human population density and major road networks. This investigation contributes valuable insights that enhance our comprehension of canine rabies transmission dynamics, thereby guiding effective control strategies. The knowledge gained holds the potential to aid in eliminating canine rabies in Sarawak and other regions in east Malaysia.

To investigate the seroprevalence of Toxoplasma gondii infection in patients with malignant tumors, we aimed to provide insights into improving the prognosis and quality of life of these patients. A total of 721 patients with malignant tumors admitted to the Affiliated Hospital of Dali University from November 2020 to May 2022, along with 100 healthy volunteers from the hospital during the same period, were enrolled. Demographic data and serum samples were collected, and serum-specific IgG and IgM antibodies against T. gondii were detected using an enzyme-linked immunosorbent assay. Patients were considered positive for T. gondii infection if either IgG or IgM antibodies were detected. The seroprevalence of specific IgG and IgM antibodies was compared between patients with malignant tumors and healthy volunteers. The positivity rates for anti-T. gondii antibodies in patients with malignant tumors was significantly higher than that in healthy volunteers (31.2% vs. 13.0%; χ² = 14.141, P < 0.01). Pairwise comparisons revealed that the positive rates of serum anti-T. gondii antibodies in patients with various types of malignant tumors were significantly higher than those in healthy volunteers (all P values < 0.01). There was no statistically significant difference in the average age and sex composition between patients with malignant tumors and healthy volunteers (P > 0.05). The results indicate a high seroprevalence rate of T. gondii infections among patients with malignant tumors, which was significantly higher than that among healthy volunteers.