Thesis (Bachelor of Science in Microbiology)

Permanent URI for this collectionhttps://hdl.handle.net/10361/28394

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Open Access
A bacteriological study of public bus and bus stop surfaces in Dhaka: identifying GLASS pathogens and analyzing their antibiotic resistance pattern
(BRAC University, 2026-01) Rahman, Britney; leen, Isha; Anwar, Mahmuda; Mokaddas, Mohosina; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
Due to overcrowding, humid environment and unsanitary conditions, public buses of Dhaka city can be a probable reservoir for pathogenic and antimicrobial resistant bacteria. This study focuses on identifying the Global Antimicrobial Resistance and Use Surveillance System (GLASS) guidelines’ priority bacteria in common touch surfaces of buses and bus stops, and providing a proper insight on the antimicrobial resistance (AMR) pattern of these bacteria. Samples collected from seats, grab rails and bus stops were spread on different selective media. Based on colony morphology bacteria were presumptively selected, then polymerase chain reaction (PCR) was performed. Upon identification of target bacteria, the analysis of their AMR pattern was done using Kirby-Bauer disc diffusion method. Among the 30 samples, 60.0% were positive for Klebsiella pneumoniae, 36.7% for Vibrio species, 33.3% for Acinetobacter baumannii, 20% for Staphylococcus epidermidis, 16.7% for Enterococcus spp. and/or P. aeruginosa, and 10.0% for Staphylococcus aureus and/or Salmonella species. Samples taken from cloth surfaces had the highest bacterial count, while acrylic paint and steel surfaces had a relatively lower count. Among the nine bacteria, all bacteria except for A. baumannii, Salmonella species and P. aeruginosa showed an alarmingly high level of multidrug-resistance, with K. pneumoniae showing the highest resistance, 95%. The detection of multidrug-resistant bacteria in public buses, emphasise these transportation as being an important reservoir for clinically significant pathogens and the dissemination of antimicrobial resistance genes to the environmental microbiome. The findings of this study call for an urgent need for improving the overall conditions of buses and ensuring proper cleaning practices in public transports.
Open Access
A comparative analysis of expanded quantitative urine culture and standard urine culture methods in patients with urinary tract infections
(BRAC University, 2026-01) Srabony, Tajri Hasan; Kunder, Stella Bijoyee; Shafi, K M Abdullah Hel; Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
Urinary tract infections (UTI) are one of the most common bacterial infections of humans. Accurate diagnosis of the cause of UTI is necessary for effective treatment. Even though clinically Standard Urine Culture (SUC) is common for detecting bacterial presence in urine samples, latest reports show that Expanded Quantitative Urine Culture (EQUC) provides better diagnostic sensitivity compared to SUC. To test this, SUC and EQUC methods were compared to analyse bacterial load and diversity using urine samples collected from 20 patients with UTI symptoms and 20 healthy controls in this study. Samples were diluted and inoculated on nutrient agar, HiChrome UTI agar, MacConkey agar and blood agar for SUC method, then incubated at 37°C for 24 hours under aerobic conditions. On the other hand, for EQUC, in addition to all the media, chocolate agar was used with different conditions like carbon-enriched, anaerobic environment with incubation at 37°C for 48 hours. Colony characteristics and polymerase chain reaction (PCR) were performed for bacterial detection. Antibiotic susceptibility test was conducted by the Kirby-Baur method. On nutrient agar medium, EQUC yielded 5-fold higher bacteria than SUC and portrayed higher bacterial diversity. While several bacterial species for example, klebsiella spp., Staphylococcus aureus, and Pseudomonas aeruginosa was detected by SUC and EQUC based on colony characteristics, EQUC exclusively detected the presence of Staphylococcus haemolyticus. Seventy-five percent of presumptive Klebsiella and 73.3% of presumptive E. coli were confirmed by PCR. AST was performed on E. coli and Klebsiella. Notably, bacteria grown via EQUC showed a diverse resistance pattern compared to SUC. Further molecular diagnoses will be performed to validate these findings.
Open Access
Detection and antimicrobial resistance profiling of nosocomial bacterial pathogens in two tertiary care hospitals of Dhaka, Bangladesh
(BRAC University, 2026-02) Rahman, Arifa; Palma, Delcy Margarate; Pratyasha, Tahrim Hossain; Monjurul Haque, Fahim Kabir; Department of Mathematics and Natural Sciences
Nosocomial infections remain a significant global health burden, posing persistent challenges in hospital settings, including in Bangladesh. Prompt identification of causative agents and appropriate antimicrobial therapy are essential, as delayed or inadequate treatment increases patient morbidity and mortality. This study investigated the prevalence and antimicrobial resistance patterns of most ESKAPE pathogens- Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, —excluding Enterococcus faecium and Enterobacter species, known for high virulence and multidrug resistance in hospital-acquired infections worldwide. However, Escherichia coli was included in this study as it was one of the most prevalent bacteria found in the hospital environment. Environmental swabs were collected from high-touch surfaces, including bed rails, bed sheets, nursing tables, and saline stands, across ICU, NICU, and children’s wards of two tertiary hospitals in Dhaka. Samples were serially diluted, cultured on selective media, and presumptively identified by colony morphology, with confirmation via polymerase chain reaction (PCR) and gel electrophoresis. Antimicrobial susceptibility was assessed using the Kirby–Bauer disc diffusion method. From 22 samples, Klebsiella pneumoniae was most prevalent (36.6%), followed by Staphylococcus spp. and Escherichia coli (18.18%). Acinetobacter baumannii (13.64%), and Pseudomonas aeruginosa (9.1%) with the lowest amount of prevalence. High resistance was noted against Beta-lactams (41.18% – 64.71%) and macrolides (47.06%), while lower resistance was found against carbopenem. MDR rates were highest in Staphylococcus species and Escherichia coli (100%), followed by Klebsiella pneumoniae (75%), Pseudomonas aeruginosa (50%), and Acinetobacter baumannii (33.3%). These findings underscore the urgent need for continuous surveillance, stringent infection control, and rational antibiotic use to mitigate multidrug-resistant pathogens in hospital environments.
Open Access
Analysis of antimicrobial resistance in acinetobacter baumannii and klebsiella pneumoniae from patients with wound infections
(BRAC University, 2025-12) Farid, Tanzim Bin; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
This study assessed the antimicrobial resistance profiles, key resistance genes, and hemolytic phenotypes of the organisms Acinetobacter baumannii and Klebsiella pneumoniae isolated from 61 pre-surgical traumatic leg wound samples in Dhaka. Of the specimens, 34 (55.7%) yielded target organisms: 15 A. baumannii and 19 K. pneumoniae. Both species demonstrated extremely high multidrug non-susceptibility across all tested antibiotic classes, with A. baumannii showing complete resistance to several agents. Colistin and Tigecycline remained the only antibiotics with comparatively lower resistance. All isolates exhibited γ-hemolysis, indicating the absence of RBC lysis. Molecular testing confirmed the presence of class 1 and class 2 integron integrase genes in A. baumannii, supporting the observed co-resistance patterns. These findings underscore a severe local resistance burden that compromises empiric therapy, highlight the need for routine culture-guided management, and emphasize the importance of strengthened antimicrobial stewardship and infection-control measures in trauma care settings.
Open Access
Assessment of airborne bacterial pathogens and antimicrobial resistance in selected urban areas of Dhaka city
(BRAC University, 2025-12) Sami, Md. Kawser Bhuiyan; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
Airborne microorganisms in urban environments pose a substantial but often neglected public health risk, particularly in densely populated cities such as Dhaka, where intense human activity, traffic congestion, and inadequate environmental controls can facilitate the spread of pathogenic bacteria. This study investigated the presence, spatial distribution, and antimicrobial resistance patterns of selected airborne bacterial pathogens across ten locations in Dhaka city, including Badda, Khilgaon, Aftabnagar, Mohakhali, Mirpur-10, Mirpur-12, Hatirjheel, Farmgate, Panthapath, and TB Gate Quarter. Air samples were analyzed for Pseudomonas spp., Klebsiella spp., Staphylococcus aureus, Acinetobacter baumannii, and Escherichia coli using selective culture methods followed by molecular confirmation through DNA extraction, polymerase chain reaction (PCR), and gel electrophoresis, yielding characteristic amplicons of 618 bp, 130 bp, 279 bp, 353 bp, and 585 bp, respectively. The distribution of airborne bacteria varied notably among sites, with Khilgaon showing the highest diversity of detected pathogens, while Hatirjheel samples showed no detectable target organisms. Antibiotic susceptibility testing revealed an alarming prevalence of multidrug resistance among all isolates, as Staphylococcus aureus exhibited 100% resistance to all tested antibiotics, E. coli and Klebsiella pneumoniae showed complete resistance to most antibiotics with only partial sensitivity to nitrofurantoin and trimethoprim, and both Pseudomonas spp. and A. baumannii demonstrated extensive resistance, remaining mainly susceptible to last-resort antibiotics such as colistin and selected fluoroquinolones. Overall, the findings highlight the presence of multidrug-resistant airborne bacterial pathogens in Dhaka’s urban air and underscore the urgent need for routine air quality surveillance and strengthened public health and antimicrobial resistance control strategies.
Open Access
Occurrence and antibiotic resistance pattern of gram-negative bacteria isolated from restaurant table surfaces
(BRAC University, 2026-01) Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
Pathogenic bacteria present on frequently touched surfaces represent a significant public health concern, particularly due to their potential to spread antibiotic-resistant infections. This study aimed to isolate and characterize pathogenic bacteria from restaurant (15 restaurant table surfaces) in Dhaka city and to evaluate their antibiotic susceptibility patterns. A total of Acinetobacter, Escherichia coli (N=5), Salmonella spp. (N=6), Shigella spp. (N=15), Vibrio spp. (N=14), Klebsiella pneumoniae (N=18), and Staphylococcus aureus (N=1) were analyzed against six commonly used antibiotics: Vancomycin, Amoxicillin, Azithromycin, Cefepime, Kanamycin, and Tetracycline. All Gram-negative isolates demonstrated 100% resistance to Vancomycin, indicating its ineffectiveness against these organisms. High resistance to Amoxicillin was observed among E. coli (80%), Salmonella spp. (83%), Shigella spp. (87%), Vibrio spp. (64%), and K. pneumoniae (83%). In contrast, Kanamycin, Cefepime, and Tetracycline showed comparatively higher effectiveness, particularly against E. coli, Shigella spp., Vibrio spp., and K. pneumoniae. Klebsiella pneumoniae exhibited the highest sensitivity to Cefepime (84%), while Shigella spp. showed notable sensitivity to Kanamycin (80%) and Cefepime (74%). Intermediate susceptibility was most prominent for Azithromycin and Cefepime across several isolates, especially in Salmonella spp. and Vibrio spp. The single Staphylococcus aureus isolate showed complete resistance to Vancomycin and Amoxicillin but remained fully sensitive to Azithromycin, Cefepime, and Tetracycline. Although identification and resistance profiling were based on conventional microbiological and phenotypic methods, molecular confirmation using polymerase chain reaction (PCR) targeting species-specific genes and antibiotic resistance determinants would further enhance the accuracy and reliability of pathogen identification. Overall, the findings highlight the presence of multidrug-resistant pathogenic bacteria on restaurant table surfaces, emphasizing the need for improved hygiene practices, molecular surveillance, and continuous monitoring of antibiotic resistance to reduce public health risks.
Open Access
A comparative assessment of bacterial load and other high-risk factors of necrotizing enterocolitis among neonates in Bangladesh
(BRAC University, 2026-01) Shanta, Nusrat Jahan; Tabassum, Ummay Sumaiya; Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
Necrotizing enterocolitis (NEC) is a serious inflammatory disease of the gastrointestinal tract that mainly affects preterm, low birth weighted neonates and remains an important cause of neonatal morbidity and mortality. In Bangladesh, evidence describing both intestinal bacterial burden and clinical high risk factors in NEC is still limited. This case-control study assessed bacterial load, different bacterial detection, and high risk factors among neonates in Bangladesh. A gender and gestational age matched case-control study was conducted at Ad-din Medical College Hospital, Bangladesh. The study population consisted of 66 preterm neonates (gestational age 28 to 36 weeks, birth weight up to 1.5 kg), including 33 NEC cases and 33 non-NEC controls. NEC cases were identified during sample collection based on key clinical features, including a positive occult blood test (OBT), abdominal distension, and the presence of bubble gas. Stool specimens were cultured on selective and differential media to measure bacterial load (CFU/ml) and to identify presumptive organisms based on colony morphology. PCR was performed to identify Escherichia coli and Klebsiella pneumoniae; PCR for other suspected organisms could not be performed due to unavailability of primers. To assess the significance of crude and adjusted odds ratio (aOR) of clinical relevance, Fisher’s test and Chi-square test were applied. Compared with NEC cases, controls showed a higher overall bacterial load, with a mean load of 1.25 × 107 CFU/ml in NEC and 2.21 × 107 CFU/ml in controls, representing an approximately 1.8 times higher load in the control group. However, PCR based detection identified E. coli and K. pneumoniae more frequently in NEC cases than in non-NEC. Growth on selective media suggested organisms such as Staphylococcus epidermidis, Staphylococcus saprophyticus, and Pseudomonas aeruginosa, along with several unidentified isolates. Several factors were analyzed including congenital heart disease, cardiogenic shock sepsis, formula feeding, breastfeeding, seizures and blood transfusion, only both type feeding demonstrated statistically significant difference between two groups (aOR: 0.8254; 95% CI: 0.2280-2.719; p < 0.05). Moreover, multidrug resistance was common in K. pneumoniae and E. coli isolates, and E. coli showed higher antimicrobial resistance. Our findings provide insight into clinical and microbiological parameters that may be useful for characterizing NEC. Because NEC is a complex inflammatory condition, further studies examining how multiple risk factors interact are needed to help lower the risk and impact of this devastating disease.
Open Access
ORAL candidosis in intensive care unit patients a comprehensive review (2005–2025)
(BRAC University, 2025-12) Zidan, Junhi; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
Oral candidosis is a common opportunistic mycotic infection in intensive care (ICU) with colonization rates quoted between 27% and 53% depending on when sampling occurs, the method of collection and the critical illness severity. It has been traditionally considered a focal mucosal infection, but increasing epidemiological data indicate oral candidosis represents a clinically relevant source of lower respiratory tract colonization and invasive candidemia, especially in mechanically ventilated adults (Nascimento et al., 2024; Noppè et al., 2024). The profound immune dysregulation of critical illness, broad-spectrum antibiotic exposure, invasive medical devices and impaired oral hygiene provide a conducive environment for such Candida overgrowth. This narrative review of literature accumulated over a period of 2 decades (2005-2025) sought to summarize the evidence on the epidemiology, microbiology, pathogenesis, risk factors for development, methods and tests employed in diagnosis, patterns of antifungal resistance as well as therapy and clinical outcomes related to oral candidosis among critically ill patients. Oral candidosis is considered as a marker for risk to systemic infection and its treatment. There is a clear need for improved epidemiological monitoring, standardized diagnostic pathways, integrated approaches to oral-care informed by specialist assessment and antifungal stewardship that are based on a secure evidence-base in order to reduce morbidity and mortality from this frequently overlooked complication of critical illness.
Open Access
Bacteriological comparison of oral swab samples collected from conventional cigarette smokers and e-cigarette smokers
(BRAC University, 2025-11) Das, Indrajit; Sarwar, Istiak; Ahmed, Plabon; Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
This study explored the impact of Conventional Cigarette Smoker (CCS), Electronic Cigarette Smoker (ECS), and Conventional Cigarette Smoker+Electronic Cigarette Smoker (CCS+ECS) use on the oral microbiome in a population from Bangladesh, where clinical research on e-cigarette users remains scarce. Oral swab samples were collected from a total of 40 participants, including 10 e-cigarette users, 10 conventional cigarette smokers, 10 dual (E-Cigarette and Conventional Cigarette) users, and 10 non-smokers. Samples were cultured and Gram stained to identify the presence of Gram-positive and Gram-negative bacteria. In terms of culture-based study, Nutrient Agar (NA) medium and Blood Agar Plates (BAP) being used. The average total aerobic count on NA medium showed difference among the groups. The highest CFU/mL count were observed on CCS group (4.8 × 10⁹ CFU/ml), followed by NS group (4.6 × 10⁹ CFU/ml), CCS + ECS group (3.9 × 10⁹ CFU/ml) and ECS (2.8 × 10⁹ CFU/ml). In contrast, Blood Agar Plates (BAP), being enriched and capable of revealing hemolytic activity, provided an insight into bacteria that may be opportunistic or pathogenic whereas ECS showed the highest overall bacterial load, with BAP counts reaching 1.5 × 10⁷ CFU/mL. CCS and CCS+ECS had comparable levels, ranging from 6.0 to 6.5 × 10⁶ CFU/mL, while NS showed 7.7 × 10⁶ CFU/mL. A significant difference between the ECS group, CCS group (p = 0.02) and CCS + ECS group (p = 0.02), indicating that e-cigarette users may harbor a greater abundance of fastidious bacterial species compared to other groups. It was hypothesized that smoking and vaping would disturb the natural oral microbial balance, increasing suspected harmful bacteria. In this case, we did the Gram-staining method and the findings revealed that CCS and ECS exhibited a higher presence of Gram-negative bacteria compared to other groups. CCS displayed a dominance of Gram-positive bacteria, suggesting a unique microbial response to tobacco exposure. ECS showed a slightly decreased Gram-negative count compared to NS, although the NS and CCS+ECS shared similar microbial profiles overall. Despite noticeable changes in bacterial composition, overall microbial diversity remained relatively stable, implying that host-related factors like genetics and hygiene may also have played a role. These results highlighted the compounded risks of e-cigarette and conventional cigarette use, questioning the idea of vaping as a more secure substitute to smoking. The pressing need for preventive health interventions and continued investigation of the long-term oral health outcomes of smoking and vaping was highlighted by the research, particularly in emerging markets such as Bangladesh.
Open Access
Isolation of mobile colistin-resistance (mcr) gene-harboring Escherichia coli from chicken droppings in Dhaka
(BRAC University, 2025-09) Rahman, Mohibur; Biswas, Nilanjana; Safa, Afrin Alam; Sabin, Tasmia; Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
The use of antibiotics in poultry industries across the low and middle-income countries is increasing rapidly, contributing to emergence of resistance against the last line of drug like colistin causing public health threat. Therefore, this study aimed to investigate the prevalence of Mobile Colistin Resistance (mcr) genes in E. coli isolated from the fecal samples of broiler chickens in Dhaka city. A total of 50 fecal samples were collected from food markets and residential areas of Dhaka city. The samples were processed and streaked onto selective media to presumptively isolate E. coli. The isolates were further confirmed by polymerase chain reaction (PCR) analysis, targeting 16s rRNA regions. Detection of mcr genes was performed by employing multiplex PCR of mcr-1 to mcr-5 and mcr-6 to mcr-9, while mcr-10 gene was amplified by singleplex standard PCR. Lastly, phenotypic expression was assessed by the broth microdilution method (BMD) to determine the minimum inhibitory concentration (MIC). A total of 47 E. coli isolates were presumptively isolated from selective media and subsequently 41 confirmed by PCR followed by plasmid-mediated detection of mcr resistance genes. Among E. coli isolates, 3 carried mcr-1 (7.3%), 33 mcr-3 (80.5%), 12 mcr-6 (29.3%), 2 mcr-7 (4.9%) 28 mcr-8 (68.3%) and 1 mcr-9 (2.4%), mcr-2, mcr-4, and mcr-10 were not detected in any of the isolates of E. coli. Phenotypic susceptibility testing of the isolates were carried out by using BMD method, revealing that most of the isolates harboring mcr genes are resistant to colistin at MIC up to 4 ug/mL. The high prevalence of various mcr genes, notably mcr-3 and mcr-8, indicated that colistin resistance had been extensively disseminated in bacteria from chickens. Such findings indicate industrial poultry chicken as a potential source of multidrug-resistant pathogens. 5
Open Access
Assessment of antibiotic resistance profiles of Escherichia coli isolates in Dhaka city’s municipal water supply
(BRAC University, 2025-08) Rahman, Mehnaz; Rafid, Shahazad Ruhul; Chaity, Sadia Sharmin; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
Antimicrobial resistance (AMR) is an alarming increasing trend at present leading to a range of health complications. This study focused on the analysis of municipal household water in the south and north of Dhaka, Bangladesh, with conclusive results of 81.16% fecal coliform contamination in the samples and confirmed 53.33% of Escherichia coli presence. According to the molecular evaluation, the most pervasive ESBL gene was found to be SHV at 32.35% and in terms of carbapenem resistance, both NDM and KPC had similar trends at roughly 3%. Upon screening the isolates, 49% of them were revealed to be multidrug resistant and 21% portrayed extensive drug resistance, leading to complexity of therapeutic choices. The results suggest the urgency of improvements for the water treatment system in Dhaka as well as standard monitoring regularly in order to mitigate the prevalence and consequences of antibiotic resistance rooting from mainstream water supply in the urban areas.
Open Access
Identification and antibiotic susceptibility profiling of Staphylococcus aureus in oral samples from students at BRAC University
(BRAC University, 2025-09) Arin, Tanzin Rahman; Hasan, Tasmiah; Adry, Shahamida Jahan; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
This study investigated the prevalence of Staphylococcus aureus (S. aureus) in oral swabs collected from Brac University students and assessed the antibiotic resistance profiles of the isolates. A total of 50 samples were cultured on Mannitol Salt Agar and subsequently on Nutrient Agar. Of these, 32 samples exhibited bacterial growth, with S. aureus identified in 16 cases. The prevalence of S. aureus was higher among male students compared to female students. Polymerase chain reaction (PCR) analysis confirmed the presence of S. aureus, as indicated by distinct 275 bp bands in positive samples. Antibiotic susceptibility testing revealed that 75% of the isolates were resistant to both Ciprofloxacin and Levofloxacin, which are classified as Fluoroquinolones. In contrast, the majority of isolates remained sensitive to Linezolid, Chloramphenicol, and Doxycycline. These findings underscore the necessity for continuous surveillance of oral S. aureus to monitor resistance patterns and guide effective treatment strategies.
Open Access
Identification and antibiotic susceptibility profiling of Escherichia coli isolated from water sample and vendor’s hand swab in Dhaka Metropolitan, Bangladesh
(BRAC University, 2025-09) Atique, Fahmida Bintey; Rahman, Mahadeenur; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
The study was focused to look at the microbial composition of water used in vegetable markets and hand swabs of vegetable market vendors to find out whether it can be a source of E. coli that are resistant to antibiotics. The samples were collected from four different markets located in four distinct areas of Dhaka. This research aimed to find out the degree of antibiotic resistance among Escherichia coli isolated from water and hand swab samples. From the four selected areas 36 samples ( 24 water samples and 9 hand swab samples) were collected . To be more specific there were two types of water samples, one is vegetable wash water and other is the source water. From analyzing the samples it indicates that vegetable washed water samples contain the most bacterial growth among three types of sample. Most bacterial isolates displayed modest intermediate levels which is between 3.45% and 41.38%, with Gentamicin and Kanamycin having the highest levels. On the contrary, two of the antibiotics Erythromycin and Ampicillin have shown considerably low levels of sensitivity to the isolates while expressing 89.66% and 100.00% of resistance respectively. The lowest rate of intermediate, on the other hand, is within 3%-40% across all isolates. Different antibiotic resistance characteristics might be seen in other isolates. Overall, among the isolates, there were 48.30% isolates showing sensitivity, 48.30% with MDR patterns, and 3.4% with extended drug resistance (XDR). It is alarming that some strains of Escherichia coli can cause severe illness like septicemia, meningitis, rheumatoid arthritis, reactive arthritis, atherosclerosis, and haemolytic uremic syndrome.
Open Access
Clonality of MDR/XDR Acinetobacter baumannii
(BRAC University, 2025-09) Anwar, MD Nahian; Badhon, Fatema; Amin, Shubha; Rashid, Sajid ur; Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
The rapid expansion of multi drug-resistant (MDR) and extremely drug-resistant (XDR) Acinetobacter baumannii over the last few decades is a rising health concern. This study evaluated the efficacy of last-line antibiotics against Acinetobacter baumannii isolates collected from Birdem Hospital, Dhaka, Bangladesh. Current study analyzed data from 50 confirmed A. baumannii isolates collected between October-November 2024. A. baumannii were cultured on selective media to isolate pure colonies at 44°C and the antibiograms for carbapenem drugs including colistin and others were determined by Vitek®2 along with traditional Kirby-Bauer disk diffusion method. Among the 50 isolates, 60% (30) were from female patients and 40% (20) from males. A significant number of samples (40%) were collected from ICU patients. Among the patients, 90% (45) were diabetic and 5% (5) were non-diabetic. Ventilator-associated pneumonia (38%) was the most common infection, followed by chronic kidney disease (32%) and acute kidney infection (26%). Out of the 50 isolates tested, 88% were identified as MDR, while 14% were classified as XDR. The prevalence of XDR and MDR A. baumannii strains were influenced by hyperglycemia. Also, the majority (44%) of the age group in this study was 51-70, which is a very vulnerable age group in terms of immune response. However, the second highest (34%) age group was 31-50 years which was alarming because it denoteed the severity of AMR among different age groups. The findings emphasized the urgent need for antimicrobial stewardship programs and alternative treatment strategies to combat MDR/XDR A. baumannii. Ongoing surveillance and research on resistance mechanisms are crucial for guiding clinical and policy decisions.
Open Access
Detection and antimicrobial resistance profiling bacteria isolated from seawater, major bathing beaches of Cox’s Bazar, Bangladesh
(BRAC University, 2025) Dewan, Mary; Naser, Iftekhar Bin; Department of Mathematics and Natural Sciences
Coastal bathing waters are potential reservoirs of pathogenic bacteria, posing serious risks to public health. Cox’s Bazar, the world’s longest natural beach and a highly visited tourist destination in Bangladesh, lacks updated data on microbial safety. This study aimed to assess the bacteriological quality of seawater from major bathing sites in Cox’s Bazar, focusing on two key pathogens and their antimicrobial resistance patterns. Seawater samples were systematically collected from four popular beaches—Sugandha, Laboni, Him Chori, and Inani. Bacterial isolation was carried out using selective media: MacConkey agar for Escherichia Coli, TCBS agar for Vibrio cholerae. Presumptive isolates were purified, confirmed by PCR, and subjected to antimicrobial susceptibility testing (AST) against 14 commonly used antibiotics following standard disc diffusion methods. A total of 260 bacterial isolates were confirmed, comprising 114 E.coli, and 146 V. cholerae. AST results showed varied susceptibility patterns. Overall, most isolates exhibited high susceptibility to imipenem, doxycycline, and chloramphenicol, while notable resistance was observed against vancomycin and ampicillin. V. cholerae isolates demonstrated the highest proportion of susceptibility, whereas E.coli showed more diverse resistance profiles. The detection of pathogenic bacteria and their multidrug-resistant traits in bathing waters of Cox’s Bazar highlights a significant public health concern. Continuous monitoring and proper management strategies are urgently needed to ensure safe recreational water quality and prevent waterborne disease outbreaks.
Open Access
Prevalence and risk factors of bacterial vaginosis during pregnancy: a review
(BRAC University, 2025-09) Islam, Taima; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
Bacterial vaginosis (BV) is a polymicrobial disorder characterized by a decrease in Lactobacillus species and an overgrowth of facultative and anaerobic bacteria in the vaginal fluid. It is essentially an underappreciated problem, as BV has been implicated in adverse pregnancy outcomes such as preterm labour and delivery, preterm premature rupture of the membranes, low birth weight, spontaneous abortion, and postpartum infections. BV is one of the most common vaginal infections worldwide, and its prevalence is estimated to range between 10% and 30% in pregnant women according to geographic, ethnic, and care settings. Although often asymptomatic, BV may cause vaginal discharge, malodour, and discomfort. Significantly, both symptomatic and asymptomatic cases are associated with substantial maternal and neonatal complications, including preterm delivery, low birth weight, and postpartum sequelae. The prevalence of BV in pregnancy is determined by demographic features (age, race, socioeconomic status), behavioural factors (unprotected intercourse, douching), and medical history. Hormonal shifts and changes in vaginal pH during pregnancy also increase susceptibility to infection. Diagnosis is typically made using Amsel’s criteria and Nugent scoring, and treatment usually involves antibiotics, specifically metronidazole or clindamycin. However, caution should be exercised in their use due to the potential risks to the developing fetus, such as teratogenic effects and increased risk of preterm birth. Addressing persistent BV is a significant challenge, underscoring the need for proactive and responsible preventive follow-up of BV in prenatal care. Early screening, particularly in high-risk populations, is not just crucial but a proactive step towards reducing complications and ensuring the health of both mothers and newborns. Given the global burden of disease, the World Health Organization (WHO) advocates for screening and treatment of symptomatic pregnant women, with all HIV seropositive cases. However, the need for additional research to elucidate the biological pathways responsible for the association between BV and preterm birth and Low birth weight is urgent. This research is crucial to determine effective prenatal interventions that can interrupt these pathways, underscoring the importance of work in this field.
Open Access
The microbiome-cancer nexus: exploring female reproductive tract dysbiosis in gynecological malignancies
(BRAC University, 2025-09) Mehrin, Sayeda; Fabiha, Nujhat; Deen, Nadia Sultana; Department of Mathematics and Natural Sciences
A specific microbiome is maintained to sustain equilibrium and good reproductive health in females. Unlike the uterus, fallopian tubes, and ovaries, which may possess a low-biomass microbiome comprising a diverse array of microorganisms, the vaginal and cervical microenvironment of the majority of reproductive women is predominantly characterized by Lactobacillus species, which confer advantages to the host through symbiotic interactions. Even when the microbiota's equilibrium is upset, illnesses like cancer may be impacted by the changed immunological and metabolic signals. Gynecological malignancies may develop as a result of these modifications to the pathophysiological axis. According to recent data, gynecological tract dysbiosis, or disturbance of microbiota homeostasis, can hasten the development and spread of a number of gynecological neoplasms, including ovarian, cervical, and endometrial malignancies. Prognosis, diagnosis, prevention, and the creation of novel therapies all depend on an understanding of the connection between microbiota and gynecological cancer. This study aimed to provide an overview of the current body of information and understanding on female reproductive tract dysbiosis in gynecological cancer.
Open Access
Detection of Klebsiella pneumoniae & Listeria monocytogenes and analysis of their antibiotic resistance in Bangladeshi homemade cosmetics
(BRAC University, 10/5/2025) Mukti, Sadia Zaman; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
In Bangladesh, homemade organic cosmetics such as whitening night creams, whitening serums, soaps, face packs and scrubs are in high demand, particularly among women. Many of these products are marketed as pure organic and chemical-free. However, the potential risk of bacterial contamination remains largely unexplored. This study aimed to analyze the pathogenic bacterial load in Bangladeshi homemade cosmetics targeting 10 clinically significant bacteria, including Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, Salmonella spp., Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. As part of this group project, my individual focus was on Klebsiella pneumoniae and Listeria monocytogenes, to evaluate their prevalence and potential public health implications. A total of 22 samples were collected from online sellers who claim to sell organic homemade cosmetics. For bacterial load determination, samples were enriched in Modified Letheen Broth and plated on Modified Letheen Agar for CFU counts. Isolation and detection of Klebsiella pneumoniae were performed by using KPC agar followed by PCR confirmation. Moreover, Listeria monocytogenes was detected using Listeria Selective Oxford Agar followed by PCR confirmation as well. Antibiotic susceptibility testing (AST) was performed using the Kirby Bauer disk diffusion method against a panel of 13 antibiotics with four additional antibiotics included- Vancomycin and Linezolid for Gram-positive bacteria and Colistin and Aztreonam for Gram-negative bacteria. Out of the 22 cosmetic products tested, 20 (90.09%) were positive for Klebsiella pneumonia and 2 (9.1%) were positive for Listeria monocytogenes. For Klebsiella pneumoniae, AST performed on 22 isolates that revealed high resistance to Ampicillin (92.3%), Azithromycin (84.6%), and Ciprofloxacin (76.9%) while resistance to other antibiotics ranged between 7.7% and 23.1%. However, Listeria monocytogenes isolates displayed mixed susceptibility patterns: one isolate was largely sensitive, while the other showed resistance to several key antibiotics including Linezolid, Vancomycin, Ampicillin and Daptomycin. This study highlights the significant presence of pathogenic bacteria in Bangladeshi homemade cosmetic products. The high contamination rates and concerning resistance profiles are alarming for public health, emphasizing the urgent need for microbiological safety monitoring and consumer awareness.
Open Access
Detection of E. coli in cut fruits sold as street foods in areas of Dhaka city and assessing their antibiotic resistance
(BRAC University, 2025-06) Ria, Bibi Fatema Ismat; Haque, Fahim Kabir Monjurul; Department of Mathematics and Natural Sciences
This study investigated the prevalence and trend of antibiotic resistance of Escherichia coli in cucumber, hog plum, grapefruit, and guava fruits that are sold as cut fruits and fresh snacks as street foods in Dhaka, Bangladesh. Total 45 samples were obtained from different places in Dhaka city like, hospital areas in Shyamoli and congested areas around Gulshan lake. The results of the Xylose Lysine Deoxycholate (XLD) agar microbiological test and the PCR molecular confirmation showed that 48.89% (22/45) of the samples were contaminated with E. coli. Tests for antibiotic susceptibility using the Kirby-Bauer disk diffusion technique revealed high resistance to ampicillin (84.4%), clindamycin (86.7%), sulfamethoxazole (84.4%), and tetracycline (95.6%). Conversely, imipenem and meropenem were the most effective antibiotics, with sensitivity of 75.6% and 70%, respectively. The emergent development of multidrug resistance (approximately 90% among 22 isolates) among isolates bodes serious public health concerns regarding street foods. The findings call for the need for stricter hygiene practices, stricter food safety regulations, and continuous monitoring of antibiotic resistance among foodborne pathogens.
Open Access
Bacteriological assessment of common fly (Musca domestica) as a potential carrier for public health epidemics
(BRAC University, 2025-08) Rahman, Mizanur; Raisa, Rokaiya; Ahmed, Akash; Department of Mathematics and Natural Sciences
House fly (Musca domestica) plays a pivotal role in the transmission of various antimicrobial-resistant pathogens, posing a huge risk to public health. Both global and national research has shown that Musca domestica is an important vector of pathogens that is directly and indirectly responsible for the rapid increase of multidrug-resistant pathogens. The purpose of this study was to identify and analyze the types of bacteria commonly associated with houseflies, with a specific focus on enteric pathogens such as Escherichia coli, Salmonella spp., Shigella spp., and others. Along with that, this study has also seen the resistance pattern of these bacteria. The study was conducted primarily divided into two seasons (October-February) and (March-July) in 3 different settings (Residential area, Fish Markets, and Street food) among 7 major areas (Ramna, Shahbag, Khilgaon, Paltan, Motijheel, Jatrabari, and Dhanmondi) of Dhaka city. From these 7 different areas, 53 samples of house flies were obtained, and from those 53 specimens, around 159 isolates of different bacteria were found. From this study, the highest number of bacterial isolates was found to be of Vibrio spp. (44.65%) and Klebsiella pneumoniae (23.27%). Again lowest isolates found were Salmonella spp. (1.26%) and Pseudomonas aeruginosa (5.66%). Among the isolates, Escherichia coli showed resistance to cefixime, amixoclav and azithromycin at an alarming rate 83%, 67%, and 83% respectively. Pseudomonas aeruginosa showed 100% resistance to amixoclav and cefixime, but Klebsiella pneumoniae raised an alarm as it is 83% resistant to cefixime. Vibrio spp and Shigella spp. Showed moderate mixed results.

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