Biology subjects

Sharmin, N.

Publications and source records attributed to Sharmin, N..

3 recordsLinked to original sources

bioRxiv2022

Bacterial communities associated with the surfaces of the fresh fruits sold around Dhaka Medical College and Hospital and their anti-microbial profiles

BackgroundNow-a-days, fresh fruits are popular sources of healthy diets with low energy density. Since they are consumed raw, it may act as a source of foodborne disease and a reservoir for antibiotic resistant organisms. This study aimed to determine microbial prevalence among the fruits sold outside Dhaka Medical College Hospital (DMCH) along with their antimicrobial profiles and to detect antimicrobial resistance genes among the resistant organisms. MethodsThirty-five different types of fruits were bought from around DMCH and analyzed for the presence of bacteria. Antibiotic sensitivity was done and ESBL, AmpC {beta}-lactamase, and MBL positive strains were identified by standard methods followed by PCR to detect ESBL, AmpC {beta}-lactamase, and MBL genes. FindingsTwenty seven different organisms were isolated and identified which were-Klebsiella spp (33{middle dot}33%), Citrobacter spp (29{middle dot}64%), Enterobacter spp (22{middle dot}22%), Escherichia coli (11{middle dot}11%), and Staphylococcus aureus (3{middle dot}70%). Among them 48{middle dot}15% organisms were resistant to different antibiotics. Only one organism (Citrobacter spp) produced ESBL phenotypically (7{middle dot}69%). Two (15{middle dot}38%) were positive for AmpC {beta}-lactamase and one of these (Enterobacter spp) possessed both SHV and CTX-M15A genes by PCR. Imipenem resistance was 84{middle dot}62% of the antibiotic resistant organisms, and 10 (90{middle dot}91%) were phenotypically MBL positive by CD test, DDS test, and MHT. By PCR, one Enterobacter spp had MBL encoding gene OXA-48. InterpretationFresh fruits, contaminated with pathogens, might be a source of transmission of resistant organisms and attribute to public health issues. FundingThe office of Directorate General of Health Service, Ministry of Health and Family Welfare, Bangladesh. ImportanceFruits sold around Dhaka Medical College and Hospital (DMCH) are usually consumed by patients, patients attendant and Health care worker. This investigation emphasized not only on the extent of bacterial contamination but also attempted to measure the anti-microbial profile of these organisms isolated from the fruits commonly available and readily consumed in and around DMCH.

microbiology↗

bioRxiv2021

Immunogenicity and efficacy of Heat Inactivated Whole-Cell Vaccine to increase murine survival after Extensively drug-resistant Acinetobacter baumannii infection.

Due to the rapid emergence of extensively drug-resistant (XDR) strains worldwide there is a necessity for greater consideration for the role of preventive vaccines to combat these pathogens. The study reported the effectiveness of a heat-inactivated whole-cell vaccine (HI-WCV) against A. baumannii to produce protective immunity with evaluation of the bactericidal antibody responses in mice after intramuscular inoculation with different XDR strains of A. baumannii. Six XDR A. baumannii strains emulsified with complete freunds adjuvant (CFA) were used for intramuscular inoculation in the experimental group of mice (n=4) in three different phases on 14 days interval whereas placebo-controlled mice (n=4) received phosphate-buffered saline emulsified with CFA in same the schedule. Serum was collected from tail blood of each mouse on 10th day after each inoculation and by cardiac puncture on 14th day after lethal dose from the experimental group and after death of the placebo-controlled group. Mice inoculated with heat-inactivated whole-cell vaccine survived and showed a higher neutralizing (IgG) antibody response after 2nd (>7-fold titre) and 3rd inoculation (>12-fold titre) whereas all mice from placebo-controlled group did not survived. Sera from experimental group of mice collected (38th day) after 3rd inoculation resulted in higher serum bactericidal killing index (42.12) after three hours incubation with an XDR A. baumannii over sera collected after 1st and 2nd inoculation (50% cutoff value=14.5). These results suggest that intramuscular vaccination with heat-inactivated whole-cell vaccine stimulated IgG antibody responses that can increase murine survival after XDR A. baumannii infection.

immunology↗

bioRxiv2020

Control of Slc7a5 sensitivity by the voltage-sensing domain of Kv1 channels

Many voltage-dependent ion channels are regulated by accessory proteins, although the underlying mechanisms and consequences are often poorly understood. We recently reported a novel function of the amino acid transporter Slc7a5 as a powerful regulator of Kv1.2 voltage-dependent activation. In this study, we report that Kv1.1 channels are also regulated by Slc7a5, albeit with different functional outcomes. In heterologous expression systems, Kv1.1 exhibits prominent current enhancement ( disinhibition) with holding potentials more negative than -120 mV. Disinhibition of Kv1.1 is strongly attenuated by shRNA knockdown of endogenous Slc7a5. We investigated a variety of chimeric combinations of Kv1.1 and Kv1.2, demonstrating that exchange of the voltage-sensing domain controls the sensitivity and response to Slc7a5. Overall, our study highlights additional Slc7a5-sensitive Kv1 subunits, and demonstrates that features of Slc7a5 sensitivity can be swapped by exchanging voltage-sensing domains. IMPACT STATEMENTThe voltage-sensing mechanism of a subfamily of potassium channels can be powerfully modulated in unconventional ways, by poorly understood regulatory partners.

neuroscience↗