Phylogeographic characterization of Burkholderia pseudomallei isolated from Bangladesh.

BACKGROUND: Burkholderia pseudomallei possesses a diverse set of genes which encode a vast array of biological functions reflecting its clinical, ecological and phenotypic diversity. Strain variation is linked to geographic location as well as pattern of land uses. This soil-dwelling Gram-negative pathogen causes melioidosis, a tropical disease endemic in northern Australia and Southeast Asian regions including Bangladesh. Phylogeographic analyses of B. pseudomallei isolates by molecular typing techniques could be used to examine the diversity of this organism as well as to track melioidosis epidemics. METHODS: In this study, 22 B. pseudomallei isolates, of which 20 clinical and two soil isolates were analyzed, utilizing Real-time PCR assay and multilocus sequence typing (MLST). The sequences were then submitted to PubMLST database for analysis and construction of phylogenetic tree. FINDINGS: A total of 12 different sequence types (STs) that includes four novel STs were identified for the first time. Strains having STs 1005, 1007 and 56 were the most widespread STs frequently isolated in Bangladesh. ST 1005, ST 56, ST 1007 and ST 211 have been detected not only in Bangladesh but are also present in many Southeast Asian countries. SIGNIFICANCE: ST 1005 was detected in both soil and clinical samples of Gazipur. Most prevalent, ST 56 has been previously reported from Myanmar, Thailand, Cambodia and Vietnam, confirming the persistence of the genotype over the entire continent. Further large-scale study is necessary to find out the magnitude of the infection and its different reservoirs in the environment along with phylogeographic association.

IgG4-related retroperitoneal fibrosis: A case report of a challenging disease.

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a multi-organ immune-mediated fibroinflammatory disorder that may imitate malignancy, infectious or any other inflammatory disorder. IgG4-related retroperitoneal fibrosis (IgG4-RPF) is a rare form of IgG4-RD, diagnosis of which is often relied on radiological technology. Herein, we describe a case of 60 year old male, presenting with low back pain and weight loss for a period of 2 months and 15 days. Imaging studies showed a retroperitoneal tumorous mass along with bilateral hydroureteronephrosis, which was later confirmed to be IgG4-related retroperitoneal fibrosis on the basis of extensive histopathological analysis. Immunosuppressive therapy resulted in a decrease in fibrosis and restoration of renal function.

Association of HLA gene polymorphism with susceptibility, severity, and mortality of COVID-19: A systematic review.

HLA is crucial for appropriate immune responses in several viral infections, as well as in severe acute respiratory syndrome coronavirus-2 (SARS CoV-2). The unpredictable nature of Coronavirus Disease 19 (COVID-19), observed in both inter-individual and inter-population level, raises the question, to what extent the HLA, as part of host genetic factors, contribute to disease susceptibility and prognosis. We aimed to identify significant HLAs, those were investigated till now, for their association with COVID-19. Three databases were searched (PubMed, Cochrane library, and Web of Science) and articles published between January 2020 and May 2021 were included for in-depth analysis. Two separate teams including four observers independently extracted the summary data, with discrepancies resolved by consensus. This study is registered with PROSPERO (CRD42021251670). Of 1278 studies identified, 36 articles were included consisting of 794,571 participants. Countries from the European region appeared in the highest number of studies and vice versa for countries from South East Asia. Among 117 significantly altered alleles, 85 (72.65%) were found to have a positive correlation with COVID-19 and 33 (27.35%) alleles were observed having a negative correlation. HLA A*02 is the most investigated allele (n = 18) and showed contradictory results. Non-classical HLA E was explored by only one study and it showed that E*01:01 is associated with severity. Both in silico and wet lab data were considered and contrasting results were found from two approaches. Although several HLAs depicted significant association, nothing conclusive could be drawn because of heterogeneity in study designs, HLA typing methods, and so forth. This systematic review shows that, though HLAs play role in COVID-19 susceptibility, severity, and mortality, more uniformly designed, interrelated studies with the inclusion of global data, for use in evidence-based medicine are needed.

Melioidosis in Bangladesh: A Clinical and Epidemiological Analysis of Culture-Confirmed Cases.

Melioidosis is known to occur in Bangladesh, but there are few reports about the condition in the published international literature. We set out to review all known cases of melioidosis in the country to date, using both retrospective and prospective data. A web-based literature search was conducted to identify all published case reports, original articles and conference abstracts. Cases were also included from a prospective study conducted in 2017. Fifty-one cases were identified between 1961 and 2017. Cases have been reported from sixteen out of the 64 districts of Bangladesh. The median age of the patients at presentation was 45 years (IQR 37⁻52), with a significant male (77%) predominance. Many patients (14/39; 36%) were farmers and 83% had diabetes mellitus. A skin/soft tissue abscess was the most common primary clinical presentation (13/49; 27%), followed by septic arthritis (10/49; 20%), pneumonia, and a deep-seated abscess/organ abscess (7/49; 14%). The major challenges to the diagnosis and treatment of melioidosis in Bangladesh are the lack of resources and the lack of awareness of melioidosis. Capacity development programs are urgently required to define the burden of disease and to tackle the mortality rates.

Burkholderia pseudomallei: Its Detection in Soil and Seroprevalence in Bangladesh.

BACKGROUND: Melioidosis, caused by Burkholderia pseudomallei, is an endemic disease in Bangladesh. No systematic study has yet been done to detect the environmental source of the organism and its true extent in Bangladesh. The present study attempted to isolate B. pseudomallei in soil samples and to determine its seroprevalence in several districts in Bangladesh. METHODOLOGY AND RESULTS: Soil samples were collected from rural areas of four districts of Bangladesh from where culture confirmed melioidosis cases were detected earlier. Multiple soil samples, collected from 5-7 sampling points of 3-5 sites of each district, were cultured in Ashdown selective media. Suspected colonies of B. pseudomallei were identified by biochemical and serological test, and by polymerase chain reaction (PCR) using 16s rRNA specific primers. Blood samples were collected from 940 healthy individuals of four districts to determine anti- B. pseudomallei IgG antibody levels by indirect enzyme linked immunosorbent assay (ELISA) using sonicated crude antigen. Out of 179 soil samples, B. pseudomallei was isolated from two samples of Gazipur district which is located 58 km north of capital Dhaka city. Both the isolates were phenotypically identical, arabinose negative and showed specific 550bp band in PCR. Out of 940 blood samples, anti- B. pseudomallei IgG antibody, higher than the cut-off value (>0.8), was detected in 21.5% individuals. Seropositivity rate was 22.6%-30.8% in three districts from where melioidosis cases were detected earlier, compared to 9.8% in a district where no melioidosis case was either detected or reported (p<0.01). Seropositivity increased with the advancement of age from 5.3% to 30.4% among individuals aged 1-10 years and > 50 years respectively. The seropositivity rates were 26.0% and 20.6% in male and female respectively, while it was 20-27% among different occupational groups. No significant association was observed with gender (χ2 = 3.441, p = 0.064) or any occupational group (χ2 = 3.835, p = 0.280). CONCLUSION: This is the first study demonstrating the presence of B. pseudomallei in the environmental (soil) samples of Bangladesh. It also suggested that a large proportion of people, residing in these districts, were exposed to the organism.

Detection and genetic characterization of PVL-positive ST8-MRSA-IVa and exfoliative toxin D-positive European CA-MRSA-Like ST1931 (CC80) MRSA-IVa strains in Bangladesh.

Severe skin lesions caused by Staphylococcus aureus infection are associated with production from bacterial cells of Panton-Valentine leukocidin (PVL), a typical virulence factor of community-acquired methicillin-resistant S. aureus (CA-MRSA), as well as other toxins represented by exfoliative toxins. Through a retrospective study of 26 S. aureus strains isolated from skin lesions of diabetic patients admitted to a hospital in Bangladesh, 2 PVL-gene-positive MRSA-IVa strains and 8 PVL-negative, exfoliative toxin D (ETD) gene (etd)-positive MRSA-IVa strains were isolated. A PVL-positive MRSA-IVa strain had a type I arginine catabolic mobile element (ACME), belonged to ST8/agr-type I/spa-type t121 (a variant of t008), and harbored blaZ, tet(K), msrA, and aph(3')-IIIa, which are mostly typical characteristics found in USA300, a predominant CA-MRSA clone in the United States. Another PVL-positive MRSA strain, belonging to ST1929 (CC88)/agr-type III/spa-type t3341, was negative for ACME, but possessed blaZ and tet(K). The etd-positive MRSA-IVa strains possessed the epidermal cell differentiation inhibitor B (EDIN-B)-encoding gene (edinB) and belonged to ST1931 (CC80)/agr-type III/spa-type t11023 (a variant of t044), which was genetic trait similar to that of the European CA-MRSA ST80 clone. However, unlike the European ST80 strains, the etd-positive MRSA strains detected in the present study harbored seb, sek, and seq, while they were negative for tet(K), aph(3')-IIIa, and fusB, showing susceptibility to fusidic acid. These findings suggested that etd-positive ST1931 MRSA strains belong to the same lineage as the European ST80 MRSA clone, evolving from a common ancestral clone via acquisition of a different pathogenicity island. This is the first report of a USA300-like MRSA-IV strain, PVL-positive ST1929 (CC88) MRSA-IV, and European ST80 CA-MRSA-like etd-positive ST1931 (CC80) MRSA-IV strains isolated in Bangladesh.