Migratory birds are carriers of multidrug resistant pathogenic Escherichia coli. However, their roles in the dissemination of these resistant pathogens are still being neglected in Bangladesh. The present study was therefore carried out to detect multidrug resistant E. coli. In addition, these isolates were also screened for the presence of avian pathogenic E. coli (APEC)-associated virulence genes. A total of 66 fecal matter samples of migratory birds were screened. E. coli were isolated and identified by culturing and biochemical tests followed by polymerase chain reaction (PCR). APEC-associated virulence genes were detected by PCR. Disk diffusion assays were employed to investigate antibiogram profiles. Bivariate analysis was performed to assess correlations in resistance patterns between antimicrobials and to assess associations between virulence genes of E. coli. Among the 66 samples assessed by PCR, 55 (83.33%) were found positive for E. coli. Of these 55 isolates, the APEC-associated virulence gene fimC was detected in 67.27% of the isolates, which was significantly higher than in the cases of iucD (29.09%) and papC (5.45%) genes. In addition, three isolates were found positive for all three virulence genes, while 23 and 12 isolates were positive for one and two virulence genes respectively. In the bivariate analysis, significant associations were detected between fimC and iucD virulence genes. Using the antibiogram, all E. coli isolates were found to be multidrug resistant (MDR). The isolates exhibited 100% resistance against ampicillin and erythromycin in addition to varying percentages of resistance against streptomycin, tetracycline, ciprofloxacin, and chloramphenicol. Highly positive correlations between tetracycline and ciprofloxacin, chloramphenicol and ciprofloxacin, chloramphenicol and tetracycline were observed by bivariate analysis. To the best of our knowledge, this is the first study that reports APEC-associated virulence genes of MDR E. coli from migratory birds in Bangladesh. Results indicate that migratory birds are reservoirs of MDR E. coli isolates carrying APEC-associated virulence genes, which can seriously contribute to the development of human and animal diseases.

This work presents a Chitosan - Graphene Oxide (CS-GO) based array of ultra-thin biosensors with gold (Au) based microgap (60μm) electrode. The cross-linked GO is shown to improve the stability of chitosan substrate in aqueous medium and compatibility with microfabrication steps. The sensor patch has been evaluated for label free monitoring by immobilizing the CS-GO surface with human dermal fibroblast (HDF) cells. The cyclic voltammetry (CV) of HDF cell immobilized CS-GO surface show quasi-reversible nature with characteristic cathodic peak at 300mV and anodic peak at +300mV. Both peaks are stable and repeatable up to 50-scan cycle without any potential shift. The device shows steady state peak enhancement (1.923-11.195nA) during the DHF cell growth period (0-96h). The redox peak enhancement correlates with the cell proliferation rates over time, indicating that it could be employed for investigation of cyto-physiological state against any endo and exogenous stimulation. In addition, the developed sensor-patch was used to detect a wide range of glucose from 1μM to 20mM in vitro with a sensitivity of 0.17μA/mM. Considering these, the presented sensor-patch has a great potential for the detection of glucose level, cell-health proliferation rate at the wound site and diabetic wound monitoring applications.

Background and Aim: Houseflies (Musca domestica) are synanthropic insects which serve as biological or mechanical vectors for spreading multidrug-resistant bacteria responsible for many infectious diseases. This study aimed to detect antibiotic-resistant bacteria from houseflies, and to examine their resistance genes. Materials and Methods: A total of 140 houseflies were captured using sterile nylon net from seven places of Mymensingh city, Bangladesh. Immediately after collection, flies were transferred to a sterile zipper bag and brought to microbiology laboratory within 1 h. Three bacterial species were isolated from houseflies, based on cultural and molecular tests. After that, the isolates were subjected to antimicrobial susceptibility testing against commonly used antibiotics, by the disk diffusion method. Finally, the detection of antibiotic resistance genes tetA, tetB, mcr-3, mecA, and mecC was performed by a polymerase chain reaction. Results: The most common isolates were Staphylococcus aureus (78.6%), Salmonella spp., (66.4%), and Escherichia coli (51.4%). These species of bacteria were recovered from 78.3% of isolates from the Mymensingh Medical College Hospital areas. Most of the isolates of the three bacterial species were resistant to erythromycin, tetracycline, penicillin and amoxicillin and were sensitive to ciprofloxacin, ceftriaxone, chloramphenicol, gentamicin, and azithromycin. Five antibiotic resistance genes of three bacteria were detected: tetA, tetB, mcr-3, and mecA were found in 37%, 20%, 20%, and 14% isolates, respectively, and no isolates were positive for mecC gene. Conclusion: S. aureus, Salmonella spp., and E. coli with genetically-mediated multiple antibiotic resistance are carried in houseflies in the Mymensingh region. Flies may, therefore, represent an important means of transmission of these antibiotic-resistant bacteria, with consequent risks to human and animal health.

Biomaterials having cell adhesion ability are considered to be integral part of a cell chip. A number of researches have been carried out to search for a suitable material for effective immobilization of cell on substrate. Engineered ECM materials or their components like collagen, Poly-l-Lysine (PLL), Arg-Gly-Asp (RGD) peptide have been extensively used for mammalian cell adhesion and proliferation with the aim of tissue regeneration or cell based sensing application. This review focuses on the various approaches for two- and three-dimensionally patterned nanostructures of a short peptide i.e. RGD peptide on chip surfaces together with their effects on cell behaviors and electrochemical measurements. Most of the study concluded with positive remarks on the well-oriented engineered RGD peptide over their homogenous thin film. The engineered RGD peptide not only influences cell adhesion, spreading and proliferation but also their periodic nano-arrays directly influence electrochemical measurements of the chips. The electrochemical signals found to be enhanced when RGD peptides were used in well-defined two-dimensional nano-arrays. The topographic alteration of three-dimensional structure of engineered RGD peptide was reported to be suitably contacted with the integrin receptors of cellular membrane which results indicated the enhanced cell-electrode adhesion and efficient electron exchange phenomenon. This enhanced electrochemical signal increases the sensitivity of the chip against the target analytes. Therefore, development of engineered cellular recognizable peptides and its 3D topological design for fabrication of cell chip will provide the synergetic effect on bio-affinity, sensitivity and accuracy for the in situ real-time monitoring of analytes.

Antimicrobial resistance has recently been considered an emerging catastrophe globally. The public health and environmental threats were aggravated by the injudicious use of antibiotics in animal farming, aquaculture, and croup fields, etc. Consequently, failure of antibiotic therapies is common because of the emergence of multidrug-resistant (MDR) bacteria in the environment. Thus, the reduction in antibiotic spillage in the environment could be an important step for overcoming this situation. Bear in mind, this research was focused on the green synthesis of chitosan nanoparticles (ChiNPs) using Citrus lemon (Assam lemon) extract as a cross-linker and application in controlling MDR bacteria to reduce the antibiotic spillage in that sector. For evaluating antibacterial activity, Staphylococcus aureus and Escherichia coli were isolated from environmental specimens, and their multidrug-resistant pattern were identified both phenotypically by disk diffusion and genotypically by detecting methicillin- (mecA), penicillin- (blaZ), and streptomycin (aadA1)-resistance encoding genes. The inhibitory zone’s diameter was employed as a parameter for determining the antibacterial effect against MDR bacteria revealing 30 ± 0.4 mm, 34 ± 0.2 mm, and 36 ± 0.8 mm zones of inhibition against methicillin- (mecA) and penicillin (blaZ)-resistant S. aureus, and streptomycin (aadA1)-resistant E. coli, respectively. The minimum inhibitory concentration at 0.31 mg/mL and minimum bactericidal concentration at 0.62 mg/mL of yielded ChiNPs were used as the broad-spectrum application against MDR bacteria. Finally, the biocompatibility of ChiNPs was confirmed by showing a negligible decrease in BHK-21 cell viability at doses less than 2 MIC, suggesting their potential for future application in antibiotic-free farming practices.