Antimicrobial resistance is a major health problem, particularly in developing countries like Bangladesh, where there is a paucity of information on resistance patterns and prevalence of antimicrobial determinants. Therefore, the aims of this study were to investigate the prevalence of resistance, including multi-drug resistance (MDR), and the associated genetic determinants in Escherichia coli isolates from cloacal swabs of live broiler chickens in Bangladesh. Altogether, 400 cloacal swabs (200 from Rajshahi and 200 from Dhaka divisions) were randomly collected from individual chickens in 50 broiler farms. E. coli was isolated and identified using conventional bacteriological culture and biochemical methods. The isolates were further confirmed using genus-specific 16S rRNAtargeted polymerase chain reaction (PCR) primers. Antimicrobial susceptibilities and MDR of the isolates against nine different antimicrobial agents (ampicillin, erythromycin, tetracycline, gentamicin, ciprofloxacin, levofloxacin, trimethoprim-sulfamethoxazole, colistin sulphate, and streptomycin) were determined using the Kirby-Bauer disc diffusion method. Resistance determinants of E. coli to ampicillin (blaTEM), streptomycin (aadA1), erythromycin [ere(A)], trimethoprim (dfrA1), and tetracycline [tet(A), tet(B)] were screened using PCR. Our results showed that all swab samples were positive for E. coli. The isolates were uniformly resistant to ampicillin, tetracycline, streptomycin, ciprofloxacin, erythromycin, and trimethoprim-sulphamethoxazole. The isolates exhibited highest susceptibility to colistin sulphate (73.5%), followed by gentamicin (49%), and levofloxacin (17%). All isolates were resistant to three classes of antibiotics, 204 isolates (51%) were resistant to four classes, and 56 isolates (14%) were resistant to five. The highest prevalence of antimicrobial resistance gene was recorded for tetracycline (tet(A):95.25%; tet(B):95.25%) followed by ampicillin (blaTEM:91.25%), streptomycin (aadA1:88.25%), erythromycin (ere(A):84.75%), and trimethoprim (dfrA1:65.5%). In conclusion, surveillance for MDR bacteria in poultry is a critical piece of knowledge, which would be useful for optimizing empiric antimicrobial treatments and exploring alternative antimicrobial agents.

Antibiotic-resistant Escherichia coli (E. coli) are common in retail poultry products. In this study, we aimed to isolate and characterize multidrug resistant (MDR) E. coli in raw chicken meat samples collected from poultry shops in Sylhet division, Bangladesh, as well as to determine correlation between resistance phenotype and genotype. A total of 600 chicken meat swabs (divided equally between broiler and layer farms, n = 300 each) were collected and the isolates identified as E. coli (n = 381) were selected. Disc diffusion antimicrobial susceptibility assay showed resistance of these isolates to ampicillin, erythromycin, tetracycline, streptomycin, trimethoprim-sulfamethoxazole, chloramphenicol, and gentamicin. Polymerase chain reaction (PCR) identified several antibiotic resistance genes (ARGs) in our isolates. Among these ARGs, the prevalence of tetA (for tetracycline) was the highest (72.58%) in broiler chicken isolates, followed by sul1 (for sulfonamide; 44.16%), aadA1 (for streptomycin; 33.50%), ereA (for erythromycin; 27.41%), aac-3-IV (for gentamicin; 25.38%), and the two genes cmlA (24.87%) and catA1 (8.63%) for chloramphenicol. On the other hand, the respective prevalence in layer chicken isolates were 82.06%, 47.83%, 35.87%, 35.33%, 23.91%, 19.02%, and 5.43%. Furthermore, 49.23% of the isolates from broiler chicken were MDR, with the presence of multiple antibiotic resistance genes, including 3 (40.11%) and 4 (9.13%) genes. On the other hand, 51.09% of layer chicken E. coli isolates were MDR, with 3, 4 or 5 ARGs detected in 36.41%, 14.13%, and 0.54% of the isolates, respectively. We also found that 12.8% of broiler chicken E. coli isolates and 7.61% of layer chicken isolates carried genes coding for extended-spectrum SHV beta-lactamases. Lastly, we report the presence of the AmpC beta-lactamase producing gene (CITM) in 4.56% and 3.26% of broiler and layer chicken E. coli isolates, respectively. We found significant correlations between most of the antimicrobial resistant phenotypes and genotypes observed among the investigated E. coli isolates. Our findings highlight the need for the prudent use of antimicrobials in chickens to minimize the development of antibiotic-resistant bacterial strains.

Background: Cattle are affected by many infectious and noninfectious diseases that can lead to economic losses to the farmers in terms of reduced growth and production performance and mortality. Objectives: This study was conducted to investigate the prevalence of infectious and noninfectious diseases of cattle in Chittagong district of Bangladesh. Methods: A total of 2614 clinical cases were diagnosed at five different veterinary hospitals in Chittagong district of Bangladesh during the year 2013. Disease diagnosis was made on the basis of owner's statement, general examination, clinical signs, gross pathology, and laboratory procedures. Data were analyzed to determine disease prevalence in cattle with respect to breed, sex and season. Results: Diagnosed diseases were categorized as infectious diseases, parasitic diseases, digestive disorders, metabolic diseases, respiratory diseases and other diseases. According to our results, the prevalence of digestive disorders was the highest (45.14%) followed by parasitic diseases (30.64%), infectious diseases (9.49%), respiratory diseases (3.90%), metabolic diseases (3.18%) and other diseases (3.18%). Disease prevalence was highest in Cross-bred cattle (44. 23%) followed by Red Chittagong cattle (28.46%) and Non-descript Deshi (27.31%). Female were more susceptible to diseases (54.32%) than male cattle (45.68%). Disease prevalence varied according to seasons. Highest prevalence was recorded in summer season (37.49%) followed by rainy season (34.81%) and winter season (27.70%). Conclusions: Our large set of data on cattle disease prevalence in Chittagong district of Bangladesh provides valuable insight to design and implement priority based research on specific disease and to take efficient control strategies against the diseases.

The T-cell surface receptor, 4-1BB (CD137), has been of increasing interest to immunologists as a co-stimulatory immune checkpoint molecule over the last two decades. Ligation of 4-1BB can activate signals in CD8+ T cells and NK cells, resulting in increased proinflammatory cytokine secretion, cytolytic function and antibody-dependent cell-mediated cytotoxicity. Targeting 4-1BB, using a 4-1BB ligand (4-1BBL) or agonistic monoclonal antibodies, has delivered a new strategy to fight against cancer, autoimmune diseases and viral infections. In this review, different aspects of 4-1BB mediated antiviral responses, the mechanistic basis of such responses and future directions are discussed.

Ebola virus (EBOV) is one of the most dangerous viruses in the world which causes fatal hemorrhagic fever syndrome both in humans and nonhuman primates. Major innate immunity mechanisms against EBOV are associated with the production of interferon's that are inhibited by viral proteins. Activation of host NK cells was recognized as a leading immune function responsible for recovery of EBOV infected people. Uncontrolled cell infection by EBOV leads to an impairment of immunity. EBOV proteins interaction with host cellular proteins disrupt type I and type II interferon responses, RNAi antiviral responses, antigen presentation, T-cell-dependent B cell responses, humoral immunity, and cell-mediated immunity. These multifaceted approaches to evasion and suppression of innate and adaptive immune responses in their target hosts lead to the severe immune deregulation and "cytokine storm" that is characteristic of fatal EBOV infection. Long-term control of viral outbreaks requires the use of vaccines to impart acquired resistance and ensuing protection. Development of a safe and efficacious vaccine against EBOV has proven elusive so far, but various inventive strategies are now being employed to counteract the threat of outbreaks caused by EBOV and related filoviruses. This review highlights the host immune responses to EBOV infection, its ability to subvert host immunity and discuss recent advances in prevention of EBOV infection by vaccination.