Bangladesh is an endemic region of dengue fever and experienced an unprecedented large outbreak with more than 100,000 confirmed cases in 2019. To understand the prevalence of dengue antibody in patients and molecular epidemiological characteristics of dengue virus (DENV) in this outbreak, a total of 179 blood samples were collected from patients in 10 districts (seven divisions) covering nearly the whole country from August to December 2019. DENV NS-1 was detected in 162 samples, among which DENV-specific IgM was positive in 119 samples (73.5%), including 60.5% samples also positive for DENV-specific IgG. Sequencing of the partial C-prM gene and its phylogenetic analysis revealed predominance of DENV type 3 genotype I, accounting for 93% of samples examined. DENV-3 genotype III was identified in two samples from separate districts, and only one DENV-2 cosmopolitan genotype was found in the capital city, Dhaka. These findings suggest the predominance of DENV-3 genotype I and occurrence of DENV-3 genotype III, associated with increased incidence of recent secondary infection in Bangladesh in 2019.

Enterococcus faecalis is one of the major causes of urinary tract infection, showing acquired resistance to various classes of antimicrobials. The objective of this study was to determine the prevalence of drug resistance and its genetic determinants for E. faecalis clinical isolates in north-central Bangladesh. Among a total of 210 E. faecalis isolates, isolated from urine, the resistance rates to erythromycin, levofloxacin, and gentamicin (high level) were 85.2, 45.7, and 11.4%, respectively, while no isolates were resistant to ampicillin, vancomycin and teicoplanin. The most prevalent resistance gene was erm(B) (97%), and any of the four genes encoding aminoglycoside modifying enzyme (AME) were detected in 99 isolates (47%). The AME gene aac(6′)-Ie-aph(2”)-Ia was detected in 46 isolates (21.9%) and was diverse in terms of IS256-flanking patterns, which were associated with resistance level to gentamicin. Tetracycline resistance was ascribable to tet(M) (61%) and tet(L) (38%), and mutations in the quinolone resistance-determining region of both GyrA and ParC were identified in 44% of isolates. Five isolates (2.4%) exhibited non-susceptibility to linezolide (MIC, 4 μg/mL), and harbored the oxazolidinone resistance gene optrA, which was located in a novel genetic cluster containing the phenicol exporter gene fexA. The optrA-positive isolates belonged to ST59, ST902, and ST917 (CC59), while common lineages of other multiple drug-resistant isolates were ST6, ST28, CC16, and CC116. The present study first revealed the prevalence of drug resistance determinants of E. faecalis and their genetic profiles in Bangladesh.

Candida species are major fungal pathogens in humans. The aim of this study was to determine the prevalence of individual Candida species and their susceptibility to antifungal drugs among clinical isolates in a tertiary care hospital in Bangladesh. During a 10-month period in 2021, high vaginal swabs (HVSs), blood, and aural swabs were collected from 360 patients. From these specimens, Candida spp. was isolated from cultures on Sabouraud dextrose agar media, and phenotypic and genetic analyses were performed. A total of 109 isolates were recovered, and C. albicans accounted for 37%, being derived mostly from HVSs. Among non-albicans Candida (NAC), C. parapsilosis was the most frequent, followed by C. ciferrii, C. tropicalis, and C. glabrata. Three isolates from blood and two isolates from aural discharge were genetically identified as C. auris and Kodamaea ohmeri, respectively. NAC isolates were more resistant to fluconazole (overall rate, 29%) than C. albicans (10%). Candida isolates from blood showed 95% susceptibility to voriconazole and less susceptibility to fluconazole (67%). Two or three amino acid substitutions were detected in the ERG11 of two fluconazole-resistant C. albicans isolates. The present study is the first to reveal the prevalence of Candida species and their antifungal susceptibility in Bangladesh.

Candida auris, Candida blankii, and Kodamaea ohmeri have been regarded as emerging fungal pathogens that can cause infections with high mortality. For genotyping of C. auris, a multilocus sequence typing (MLST) scheme based on four locus sequences has been reported, while there is no typing scheme for C. blankii and K. ohmeri. In the present study, the existing MLST scheme of C. auris was modified by adding more locus types deduced from sequence data available in the GenBank database. Furthermore, MLST schemes of C. blankii and K. ohmeri were developed using the four cognate loci (ITS, RPB1, RPB2, D1/D2) and similar sequence regions to those of C. auris. These MLST schemes were applied to identify the ST (sequence type) of clinical isolates of C. auris (n = 7), C. blankii (n = 9), and K. ohmeri (n = 6), derived from septicemia or otomycosis in Bangladesh in 2021. All the C. auris isolates were classified into a single ST (ST5) and clade I, having a Y132F substitution in ERG11p, which is associated with azole resistance. Similarly, all the C. blankii isolates belonged to a single type (ST1). In contrast, six K. ohmeri isolates were assigned to five types (ST1-ST5), suggesting its higher genetic diversity. These findings revealed the availability of MLST schemes for these three fungal species for understanding their clonal diversity among clinical isolates.

Chronic infection of Helicobacter pylori represents a key factor in the etiology of gastrointestinal diseases, with high endemicity in South Asia. The present study aimed to determine the prevalence of H. pylori among dyspeptic patients in north–central Bangladesh (Mymensingh) and analyze risk factors of infection and antimicrobial resistance (AMR) determinants in the pathogen. Endoscopic gastrointestinal biopsy samples were collected from dyspeptic patients for a one-year period from March 2022 and were checked for the presence of H. pylori via the rapid urease test and PCR and further analyzed for the status of virulence factors vacA/cagA and genetic determinants related to AMR via PCR with direct sequencing or RFLP. Among a total of 221 samples collected, 80 (36%) were positive for H. pylori, with the vacA+/cagA+ genotype being detected in almost half of them. H. pylori was most prevalent in the age group of 41–50-year-olds, with it being more common in males and rural residents with a lower economic status and using nonfiltered water, though the rates of these factors were not significantly different from those of the H. pylori-negative group. Relatively higher frequency was noted for the A2147G mutation in 23S rRNA, related to clarithromycin resistance (18%, 7/39). Amino acid substitutions in PBP-1A (T556S) and GyrA (N87K and D91N) and a 200 bp deletion in rdxA were detected in samples from some patients with recurrence after treatment with amoxicillin, levofloxacin, and metronidazole, respectively. The present study describes the epidemiological features of H. pylori infection in the area outside the capital in Bangladesh, revealing the spread of AMR-associated mutations.

Background/Objectives: Enterococcus is one of the major nosocomial pathogens. The present status of antimicrobial resistance determinants and virulence factors was analyzed for current Enterococcus causing infectious diseases in Bangladesh. Methods: Clinical isolates of Enterococcus recovered from various specimens in a tertiary care hospital were analyzed. Antimicrobial susceptibility was measured by a broth microdilution test, and resistance genes/virulence factors were detected by uniplex/multiplex PCR, along with sequencing analysis as required. The sequence type (ST) of E. faecalis and E. faecium was identified based on a multilocus sequence typing (MLST) scheme. Results: For a one-year period, a total of 143 isolates (135 E. faecalis, 7 E. faecium, and 1 E. hirae) were collected. Although all E. faecalis isolates were susceptible to penicillin, high resistance rates were noted against erythromycin (87%) and levofloxacin (62%). High-level resistance to gentamicin was detected in 30% of E. faecalis and 86% of E. faecium. Vancomycin resistance due to vanA was identified in one isolate each of E. faecalis (ST1912, CC116) and E. faecium (ST80, CC17). Three E. faecalis isolates (2.2%) with ST32 or ST1902 were resistant to linezolid, harboring optrA-fexA. Conclusions: The present study identifies the vancomycin-resistant Enterococcus harboring vanA from humans in Bangladesh and shows the potential spread of optrA in multiple lineages of E. faecalis.