Biomedical subjects
Publications and source records attributed to Mustafizur Rahman.
We report the whole-genome sequence of multidrug resistant Escherichia coli RSJ-SAU.Ec.2025 isolated from the nasal swab of a cat in Dhaka, Bangladesh. The assembled genome comprises 5,318,660 bp with 50.5% guanine-cystosine (GC) content, together with putative antibiotic-resistant genes.
Colonization with difficult-to-treat-resistant Gram-negative bacteria (DTR-GNB) increases the risk of subsequent infections with limited treatment options. This study aimed to assess the burden of DTR-GNB colonization in ICU patients, explore its association with clinical outcomes, and examine genomic similarities. This secondary analysis included patients enrolled within 24 h of ICU admission between July 2023 and January 2024. Rectal swabs were collected at enrollment, on days 3, 7, and weekly during ICU stay to detect colonization. Bacterial isolates grown on selective chromogenic agar media were identified and tested for antimicrobial susceptibility using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and automated broth microdilution, respectively. Blood, urine, and/or tracheal aspirate cultures were performed if clinically suspected sepsis. Whole-genome sequencing (WGS) was performed on paired colonization and infection isolates, and genomic relatedness was assessed using FastANI, core-genome single-nucleotide polymorphism (SNP) analysis, and phylogenetic reconstruction. Among 373 patients, 181 (48.5%) were colonized with DTR-GNB; 76 (20.4%) at enrollment, and 105 (53.0%) acquired during hospital stay. Among 52 (13.9%) patients evaluated for suspected infection, 30 (57.7%) had positive cultures, predominantly Acinetobacter baumannii (n = 15) and Klebsiella pneumoniae (n = 11) of DTR-phenotypes. Compared to non-colonized patients, patients colonized with DTR-GNB had higher risks of infections (risk ratio [RR]: 2.18, 95% CI: 1.27-3.76) and longer ICU stays (median 7 vs 2 days, P < 0.001). DTR-GNB-infected patients had a higher risk of death (RR: 1.57, 95% CI: 1.34-1.84) compared to patients without DTR-GNB infection. WGS revealed that 13 of 14 paired colonization-infection isolates were conspecific, with three pairs being highly clonal; whereas the remaining pairs showed greater genomic divergence, consistent with the SNP and phylogenetic analyses. While common, more than half acquired DTR-GNB colonization from the ICU. Its association with subsequent infection and prolonged ICU stays underscores the need for enhanced infection prevention and control measures to mitigate nosocomial transmission and improve patient outcomes.IMPORTANCEThis study underscores the growing threat posed by difficult-to-treat resistant Gram-negative bacteria (DTR-GNB) in intensive care units. Nearly half of critically ill patients were colonized, with a considerable proportion acquiring these multidrug-resistant organisms during their ICU stay. Colonization with these pathogens substantially increased the risk of subsequent infections, even by the same colonizing strain, prolonged ICU stays, and likely worsened clinical outcomes due to the unavailability of susceptible antibiotics. Alarmingly, more than 90% of patients infected with DTR-GNB expired in the hospital. These findings highlight the urgent need for robust infection prevention and control strategies to curb nosocomial transmission and mitigate the impact of DTR-GNB on vulnerable patient populations. Addressing this emerging resistance phenotype is critical to improving patient safety and reducing the burden on healthcare systems.
Enterotoxigenic Escherichia coli (ETEC), a leading cause of diarrhea, is defined by heat-stable (ST) and/or heat-labile (LT) toxins and associated colonization factors (CFs). However, there is still a knowledge gap in understanding ETEC's evolution, particularly in endemic regions like Bangladesh. This study investigates the genomic attributes contributing to the rise of ETEC-associated diarrhea in Bangladesh during 2022-2023. Whole genome sequencing of 325 ETEC isolates (2022-2023), compared with historical strains (1980-2021), revealed significant evolutionary changes. Our findings showed a significant shift in ETEC toxin from LT to ST over the period 2013-2023. The most frequent virulence profile during this period was CFA/I + CS21 compared with previous years (1980-2021). The emergence of CS23-positive ETEC was reported for the first time in Bangladesh, which was considered a less common CF in previous studies. Notably, we report the four novel lineages "L26-L29" in this study through phylogenetic analysis, partly encompassing emergent CS23-positive ETEC strains. Additionally, the high prevalence of multi-drug-resistant ETEC strains and the presence of ESBL-CTX-M-resistant gene during 2022-2023 are a matter of great concern, underscoring the need for preventive measures. The switch of distinct toxin and CF combinations, the rapid emergence of CS23, ESBL-CTX-M resistance, and novel lineages may be the reason behind the increased number of ETEC diarrheal cases between 2022 and 2023. These findings highlight the rapid ETEC evolution that underscores the necessity of continued genomic surveillance to track ongoing changes.IMPORTANCEThis study expands on previous evidence, demonstrating a remarkable genomic diversity in ETEC strains from 2022 to 2023, particularly in virulence factors and AMR genes. The combined findings from these studies will be important for mitigating future diarrheal outbreaks by informing preventive measures, including future vaccine targets, and implementing antibiotic stewardship programs against ETEC infection. Importantly, this research underscores the necessity of continued genomic surveillance to track ongoing changes in ETEC. Such monitoring is essential for understanding the pathogen's evolving population structure, transmission dynamics, and resistance mechanisms.