Bangladesh Journal of Microbiology

Phytochemical Analysis and In Vitro Antimicrobial Activity of Costus speciosus Extracts

2023-05-17T07:51:07+00:00

Costus speciosus (J. Koenig) Sm., commonly known as crepe ginger, is primarily used as an ornamental plant worldwide. The aim of this research was to study the phytoconstituents of locally collected C. speciosus plant samples and test their antimicrobial effect against selected bacterial strains. Phytochemical analysis showed the presence of alkaloids, flavonoids, steroids, phenolic compounds, tannins, glycosides, and cardiac glycosides in the extracts. The extracts displayed variable degrees of antibacterial activity against the microorganisms in a bioautography experiment based on thin-layer chromatography. All the extracts showed activity against S. aureus, and none showed any activity against P. aeuroginosa. The ethanol and ethyl acetate extracts from the plant leaf and stem showed efficacy against S. typhi and B. subtilis, while the ethyl acetate extracts prevented the growth of S. pneumoniae. Only the ethanol extract from plant leaves had a negligible effect on K. pneumoniae.

Bangladesh J Microbiol, Volume 39, Number 2, December 2022, pp 46-52

In-vitro inactivation of Escherichia coli of surface water using metals

2023-05-17T07:51:08+00:00

Technology for providing clean drinking water to remote areas of low-resource nations remains a significant challenge for human life The study aimed to develop a simple technology for rural households that might be adopted to utilize the bactericidal properties of metals. Three thick metal sheets made of copper, zinc, and brass (an alloy of copper and zinc) were used in this study work. These metallic sheets were placed in three plastic (polythene) containers with base areas 11cm x 7cm each so that the metallic sheets covered the entire base areas of the respective containers. Fifty ml, one hundred ml, and four hundred ml of contaminated water from a public pond were added to each container, covered with lids, and shaken/left undisturbed at room temperature. The microbial analysis of Total Aerobic Bacteria (TAB), Total Coliform Bacteria (TCC), and E. coli was done every 24 hours up to twenty-eight days of storage at room temperature. E. coli is considered an indicator of diarrhoeal pathogens. The initial bacterial counts were TAB: 4.22 log CFU/ml, TCC: 3.15 log CFU/ml, and E.coli: 3.13 log CFU/ml, respectively. TAB count did not reduce significantly for any of the metals used in this study. Total coliform counts decreased to almost half the original for all three metals in the first 24 hours but remained almost the same afterward. However, E.coli was inactivated entirely after treatment with copper within 24h and remained constant afterward. On the other hand, brass and zinc reduced E. coli by almost half in the first 24 hours but remained almost constant throughout the rest of the measured period. The findings mentioned above, a simple copper sheet might help inactivate diarrheal bacteria and provide safe drinking water within 24 hours. As a result, this may lead to the development of an easy technique to provide clean drinking water in remote areas of low-resource nations like Bangladesh. It is crucial to determine whether the level of copper in the water is within the safe range, as regular usage of higher doses might result in copper poisoning. A future study will attempt to optimize the relationship between the water volume to the copper sheet’s exposed surface area and the treatment time.

Bangladesh J Microbiol, Volume 39, Number 2, December 2022, pp 54-59

Prevalence of Methicillin Resistant Staphylococcus aureus Carriage Amongst Healthcare Workers of Critical Care Units in Tertiary Hospitals of Jashore, Bangladesh

2023-05-17T07:51:09+00:00

Staphylococcus aureus is responsible for numerous mild to severe diseases in humans in both hospital and community settings. This problem is getting even worse for multi-drug resistant S. aureus. Healthcare workers (HCWs) are in a threat of MRSA carriage and can serve as reservoirs. Therefore, this can lead to subsequent infection and cause a nosocomial outbreak of MRSA. This cross-sectional study involved 85 healthcare workers (HCWs) from surgery units and critical care units of five different tertiary hospitals at Jashore, Bangladesh. Nasal swab samples were collected and inoculated on selective Mannitol Salt Agar (MSA) media. S. aureus was confirmed by selective growth on MSA and detection of the presence of the femA gene. Antibiotic susceptibility pattern was determined for all S. aureus isolates. Methicillin resistance was detected using both disc diffusion assay and gene specific polymerase chain reaction. S. aureus specific staphylococcal protein A (Spa) typing was also done by sequence analyses of PCR products. Among the 85 enrolled HCW personnel, 34 (40%) were carrying S. aureus followed by the S. intermedius (N=32). An overall prevalence of MRSA was found to be 3.53% (3/85). However, all the strains were susceptible to vancomycin. Additionally, 100% sensitivity was found against Trimethoprim/sulfamethoxazole and Linezolid. Sequence analysis of Spa PCR product revealed that all S. aureus isolates were of t304 spa type. None of the S. aureus was a biofilm former. This study was only a survey on the prevalence of MRSA among HCWs. Integrated surveillance for MDR MRSA carriage among HCWs is warranted to control bursts of nosocomial infections effectively. It is strongly recommended to maintain good microbiological and personal hygiene practices by HCWs.

Bangladesh J Microbiol, Volume 39, Number 2, December 2022, pp 60-66

Prevalence and Identification of Carbofuran Degrading Bacteria from Agricultural Fields and Associated Water Bodies

2023-05-17T07:51:11+00:00

The extensive use of pesticides in agricultural areas is done to assure protection against insect invasion, to raise crop production, to improve fertility and soil quality, and therefore to efficiently contribute to an agriculture-based economy. However, the unfortunate reality is that the long-term presence of these pesticides in the environment as a result of their complex and xenobiotic chemical structures leads to bioaccumulation as well as bio-magnification, which in turn causes toxicity, chronic disabilities, hormonal imbalance, reproductive and endocrine dysfunctionalities, and many other health issues in humans as well as other vertebrates and causes ecosystem derangement. Similar results are produced by one of the most widely used N-methylcarbamate-based pesticides, carbofuran. There is no better solution to this issue than breakdown of leftover pesticide in the environment to harmless, native components through biological agents, ideally indigenous bacteria. Carbofuran, one of the most widely used N-methylcarbamate-based insecticides, has comparable effects. In light of this, a study was conducted to identify and characterize bacteria that have the innate ability to not only survive pesticide applications to rice and vegetable fields, but also to use the pesticides as a source of energy and break them down into harmless, environmentally friendly components. As a result, samples were taken from a Savar rice and tomato field shortly after a pesticide application, and Carbofuran 5G was the insecticide selected to check for degradability given to its widespread use there. Bushnell Haas broth and Bushnell Haas agar media were employed for enrichment, plating, and subsequent cultures to generate pure culture, with supplemented carbofuran of different concentrations serving as the only carbon source. The identities of the 17 isolates that could grow there were verified by sequencing after PCR and product purification. The evolutionary relatedness was determined using phylogenetic analysis with MEGAX. Acinetobacter spp., Rahnella spp., Chitinophaga spp., Serratia spp., Stenotrophomonas spp., Achromobacter spp., Pseudoxanthomonas spp., and Klebsiella spp. were the bacteria that were found.

Bangladesh J Microbiol, Volume 39, Number 2, December 2022, pp 68-74

Cervical Cancer Screening and Prevention in Low- and Middle-Income Countries: A Perspective from Bangladesh

2023-05-17T07:51:12+00:00

Cervical cancer is a major public health concern for women worldwide, particularly in low- and middle-come countries (LMICs). Despite a large number of women (nearly 58 million) are at risk of this preventable cancer, the issue of cervical cancer has not become a public health priority in Bangladesh. The understanding of the challenges and opportunities in Bangladesh about cervical cancer would provide valuable insights for other LMICs also. In this article, we review the epidemiology, risk factors, awareness and treatment of cervical cancer in the context of Bangladesh. Due to lack of awareness and an organized national screening program, the majority of patients are generally diagnosed at the advantaged stages of disease, in spite of having a big window of screening opportunity at precancer stage. Most LMICs lack resources for developing a parallel health service system dedicated for cancer prevention and management. In this context, we propose some recommendations including a cost-effective screening strategy by capitalizing available resources of COVID-19 diagnostic and GenXpert labs, and an innovative female-centric primary healthcare workers and high school-based approaches for generating awareness on cervical cancer risk factors, screening and vaccination. Our proposed strategy could also be effective for other similar settings in LMICs.

Bangladesh J Microbiol, Volume 39, Number 2, December 2022, pp 76-82