Bangladesh Journal of Microbiology

Screening and Identification of Chromium Resistant Bacteria from Poultry Excreta

Md Abu Sayem Khan — 2024-03-13

The occurrence of heavy metal-resistant bacteria in the environment acts as an indicator of heavy metal pollution. The impact of heavy metal contamination in co-selection and proliferation of antimicrobial[1]resistant bacteria is well-documented in existing literature. The present study aims to determine the occurrence of chromium-resistant bacteria (CRB) in poultry feces and to characterize their antimicrobial resistance and biofilm formation ability. 28 CRBs were isolated by inoculating samples on chromium-amended media. 6 of 28 isolates were resistant to a maximum of 1000 ppm chromium. Isolated CRBs also showed varying degrees of resistance to other heavy metals, including Cd, Ni, and Hg. Biofilm formation was observed in 67.8% isolates, of which 60.7% and 7.1% were weak and moderate biofilm former, respectively. All the isolates exhibited sensitivity to Gentamicin, Chloramphenicol, Imipenem, and Amikacin. Only one isolate was multi-drug resistant. In addition, all the isolates possessed chromate reductase gene that confirmed their chromium-reducing activity. Two isolates were identified as Bacillus altituidinis and Brevibcillus parabrevis on the basis of 16s rRNA analysis. Further estimation of chromium-reduction capacity and whole genome analysis will reveal their bioremediation potential.

Bangladesh J Microbiol, Volume 40, Number 1, June 2023, pp 1-6

Multidrug Resistance Pattern of Pseudomonas aeruginosa Isolated from Patients with Nosocomial Infection

Poulomi Saha — 2024-03-13

Multidrug resistant (MDR) Pseudomonas aeruginosa is a threat to the patients having nosocomial infections as this pathogen increases the inpatients’ morbidity and mortality by slowing down the whole treatment process. The aim of this study was to evaluate multidrug resistant phenotypes among nosocomial strains of P. aeruginosa for analyzing their antibiotic susceptibility pattern. A total of 108 P. aeruginosa clinical isolates were recovered from various samples (pus, wound swab, urine, sputum, blood and tracheal aspirate) of patients with nosocomial infections. Antibiogram was performed by disc diffusion according to Kirby-Bauer method to study the antibiotic sensitivity pattern of the pathogen against 14 regularly used antibiotics (amikacin, aztreonam, ceftazidime, ceftriaxone, co-trimoxazole, ciprofloxacin, gentamicin, levofloxacin, meropenem, netilmicin, doxycycline, amoxicillin/clavulanic acid, piperacillin/tazobactam, and tigecycline) in Bangladesh. The overall frequency of drug resistance was found to be very high (53.7% - 98.1%) to all of the anti-pseudomonal drugs tested. Resistance of P. aeruginosa strains against piperacillin-tazobactam was significantly less (53.7%) as compared to other thirteen antibiotics. However, isolates showed highest resistance (98.1%) to aztreonam. Next in order of resistance were doxycycline (95.4%), ceftriaxone (94.4%), amoxiclav (93.5%), and the others. The present study suggests that regularly used medications can no longer be utilized as first line therapies for suspected pseudomonad infections. This study claims for urgent epidemiological monitoring of the MDR P. aeruginosa strains in all hospitals of Bangladesh to prevent rapid dissemination of this opportunistic pathogen.

Bangladesh J Microbiol, Volume 40, Number 1, June 2023, pp 7-13

In silico Evolutionary Insights into Prokaryotic and Eukaryotic Malate Dehydrogenases (MDH) Support the Archaebacterial Origin of Eukaryotes

Israt Dilruba Mishu — 2024-03-13

Malate Dehydrogenase (MDH) stands as a pivotal enzyme crucial for cellular energy metabolism, orchestrating the conversion of malate to oxaloacetate in both prokaryotic and eukaryotic organisms. This study delves into the evolutionary trajectories of MDH1 (cytoplasmic) and MDH2 (mitochondrial), offering substantial evidence supporting the archaebacterial origin of eukaryotes. The dataset spans nine groups, encompassing human MDH1 and MDH2, mammalian MDH1 and MDH2, amphibian MDH2, arthropod MDH2, amoeba MDH1, archaea, and bacteria. Protein BLAST analysis revealed significant sequence homology in mammalian MDH1, particularly among primates, underlining a close evolutionary connection. Conversely, lower eukaryotes, including amoeba, arthropods, and amphibians, exhibited marked divergence from human MDH1 and MDH2. Phylogenetic analysis unveils distinct clusters for MDH1 and MDH2, accentuating significant genetic diversity between mitochondrial and cytoplasmic MDH enzymes. Prokaryotic MDH sequences cluster with human mitochondrial MDH2, while MDH1 forms a separate cluster. Staphylococcus MDH aligns with archaeal MDH, emphasizing the diversity within bacterial MDH evolution. Protein variability analysis indicates noteworthy divergence of human MDH1 from prokaryotic MDH, while MDH2 displays comparatively lower divergence. Pairwise evolutionary divergence analysis sheds light on complex relationships among MDH protein sequences. Human MDH1 shows close evolutionary ties to mammalian MDH1, whereas MDH2 exhibits a unique pattern, aligning closely with mammalian MDH2, arthropods, and amphibians. Furthermore, MDH2 demonstrates closer proximity to bacterial MDH, supporting a bacterial origin of mitochondrial MDH. In contrast, MDH1 displays less divergence to archaeal MDH than its bacterial counterpart, endorsing an archaeal origin for cytoplasmic MDH. In conclusion, this study provides compelling support for the archaebacterial origin of eukaryotes, suggesting a bacterial endosymbiont within an archaeal host that evolved into mitochondria. It contributes valuable insights into MDH evolution, unraveling the intricate relationships and unique adaptations shaping the evolutionary history of eukaryotic cells.

Bangladesh J Microbiol, Volume 40, Number 1, June 2023, pp 15-24

Correlation between antibiotic resistance and biofilm formation in Klebsiella spp.

Dipan Barai — 2024-03-13

Antibiotic resistance among various microbial species is becoming a global threat to human health. MDR, or multidrug resistance, is an organism’s ability to tolerate the effects of many antimicrobial treatments. Klebsiella spp. is the major bacteria that causes a variety of illnesses, including urinary tract infections. The primary goal of this study is to look into the relationship between antibiotic resistance and Klebsiella spp. biofilm production. This study included 26 clinical isolates of Klebsiella spp. (n=26) collected from a tertiary hospital in Bangladesh. Isolates were obtained from blood, wound swabs, urine, and other sources. Following isolation and identification, ampicillin resistance was found in all MDR Klebsiella spp. isolates, followed by Cefotaxime (84.61%), Polymyxin B (84.61%), Amoxicillin (80.76%), Trimethoprim (69.23%), Doripenem (57.69%), Ciprofloxacin (57.69%), Imipenem (50.0%), Meropenem (38.46%), and Oxytetracycline (34.61%). Out of 26 clinical isolates, about 26.92% (n=7) were positive for the bla-NDM-1 gene. However, 15.8% of Klebsiella spp. (n = 4) isolates tested positive for the blaOXA-1 gene. There were no bla-KPC gene positives. Plasmid profile analysis revealed that 24 of 26 Klebsiella spp. isolates included numerous plasmids ranging in size from less than 2kb to more than 10kb. Biofilm formation found that 31% of samples were extremely positive for biofilm formation, 69% were medium biofilm formation, and (n=4) isolates were positive for biofilm resistance gene out of a total of 26 isolates. This study provides an early report on the widespread presence of carbapenem-resistant Klebsiella spp., demonstrating the need for intensive surveillance systems and research initiatives in Bangladesh to reflect the influence of multidrug resistance features in clinical isolates and their risks.

Bangladesh J Microbiol, Volume 40, Number 1, June 2023, pp 25-32

Risk Assessment and Detection of Legionella species in the Water System of A Luxury Hotel in Dhaka city, Bangladesh

Nazmun Naher — 2024-03-13

Legionella cause Legionnaires’ disease and Pontiac fever, and, more rarely, extrapulmonary infections, collectively referred to as legionellosis. Legionella pneumophila causes serious pneumonic infections, and water and Air Conditioning systems are a common source. We performed this study focusing on identifying and assessing the potential sources of Legionella spp. in a luxury hotel water system in Dhaka, Bangladesh. As hotels often have complex water distribution systems that can harbor and facilitate the growth of these bacteria, understanding the risks and implementing effective control measures is crucial for public health. This study determines the presence of Legionella spp. and potential factors contributing to their proliferation within the hotel water systems. In total 42 water samples and six swabs from 7 different points were collected multiple times between March 2018 and April 2019 and were analyzed. Legionella spp. was detected in all samples (100%) tested. The highest colony counts were observed in water samples from the hot water tank and cooling system. The findings highlight the importance of regular monitoring, maintenance, disinfection, and flushing protocols to mitigate the risk of Legionella spp., contamination, and subsequent health issues among hotel guests and staff.

Bangladesh J Microbiol, Volume 40, Number 1, June 2023, pp 33-39

Molecular Detection and Genotyping of Dengue Viruses: Current Techniques and Future Prospect

Min Kuang Lee — 2024-03-13

The Dengue virus is a prevalent mosquito-borne disease, and its global incidence has been steadily increasing due to the favorable environmental conditions that promote mosquito breeding, primarily influenced by rising temperatures. Bangladesh has been particularly hard-hit by an intense and ongoing outbreak, resulting in a surge of cases and fatalities. Effective management of this disease necessitates the implementation of robust public health measures, including rigorous surveillance and early diagnosis. While serological tests are commonly employed in clinical diagnosis, molecular methods hold a critical role in identifying the specific Dengue virus strain, thereby contributing to a more comprehensive understanding of disease severity. This article serves as an extensive review, delving into various molecular testing techniques employed for both surveillance and clinical diagnosis. It offers valuable insights for research and clinical laboratories engaged in the detection of Dengue virus RNA in mosquitoes, environmental samples, and clinical specimens. The methods covered encompass a spectrum of approaches, including conventional PCR, isothermal amplification, real-time RT-PCR, Sanger sequencing, and whole-genome sequencing, providing a holistic overview of the available techniques. These methods play pivotal roles in clinical diagnosis, outbreak analysis, vector surveillance, and vaccine development. Furthermore, the article underscores the importance of integrating these techniques into existing healthcare systems, emphasizing their significance in ensuring precise dengue diagnostics to enhance the efficiency of disease management. These molecular methods are indispensable tools that contribute to accurate diagnosis, enable effective outbreak investigation, facilitate vector surveillance, and support vaccine preparation, thereby enhancing the overall management and control of dengue, ultimately working toward mitigating its impact on public health.

Bangladesh J Microbiol, Volume 40, Number 1, June 2023, pp 41-49