Outbreaks of Vibrio vulnificus wound infections in Israel were previously attributed to tilapia aquaculture. In this study, V. vulnificus was frequently isolated from coastal but not freshwater aquaculture in Bangladesh. Phylogenetic analyses showed that strains from Bangladesh differed remarkably from isolates commonly recovered elsewhere from fish or oysters and were more closely related to strains of clinical origin.

Expelling antibiotic molecules out of the cell wall through multiple efflux pumps is one of the potential mechanisms of developing resistance against a wide number of antibiotics in Staphylococcus aureus. The aim of this study was to investigate the association between the antibiotic susceptibility profile and the prevalence of different efflux pump genes i.e., norA, norB, norC, mepA, sepA, mdeA, qacA/B, and smr in the clinical isolates of S. aureus. Sixty clinical isolates were collected from a tertiary level hospital in Bangladesh. The disc diffusion method using ten antibiotics of different classes was used to discern the susceptibility profile. polymerase chain reaction (PCR) was employed to observe the resistance patterns and to detect the presence of plasmid and chromosomal encoded genes. Among the clinical isolates, 60% (36 out of 60) of the samples were Methicillin-resistant Staphylococcus aureus (MRSA), whereas 55% (33 out of 60) of the bacterial samples were found to be multi-drug resistant. The bacteria showed higher resistance to vancomycin (73.33%), followed by ciprofloxacin (60%), cefixime (53.33%), azithromycin (43.33%), and amoxicillin (31.67%). The prevalence of the chromosomally-encoded efflux genes norA (91.67%), norB (90%), norC (93.33%), mepA (93.33%), sepA (98.33%), and mdeA (93.33%) were extremely high with a minor portion of them carrying the plasmid-encoded genes qacA/B (20%) and smr (8.33%). Several genetic combinations of efflux pump genes were revealed, among which norA + norB + norC + mepA + sepA + mdeA was the most widely distributed combination among MRSA and MSSA bacteria that conferred resistance against ciprofloxacin and probably vancomycin. Based on the present study, it is evident that the presence of multiple efflux genes potentiated the drug extrusion activity and may play a pivotal role in the development of multidrug resistance in S. aureus.

Microbial community inhabiting the intestine of the shrimp (Penaeus monodon) and their surrounding environments (e.g., water and sediment) is considered as a key contributing factor for the sustainable farming of shrimp. Indiscriminate application of antibiotics in aquaculture is a growing concern due to the emergence of antibiotic resistant bacteria (ARB), more specifically the antibiotic resistance genes (ARGs). The present study investigates the microbiome composition and 19 ARGs from four different shrimp farming systems; (i) cluster, (ii) extensive, (iii) semi-intensive, and (iv) improved extensive in the southwest coastal region of Bangladesh. In doing so, the study applied advanced 16S rRNA-based metagenomic sequencing to study the bacterial composition. Moreover, gene specific polymerase chain reaction (PCR) was employed to detect the ARGs in shrimp, water, and sediments of different farming systems. In the current study, bacteria from the phylum Proteobacteria and Firmicutes were predominant among the samples (n = 12) collected from the different farming systems followed by Actinobacteria, Bacteroidetes, and Cyanobacteria. Firmicutes was the predominant phylum in the gut of shrimp cultured in the cluster (relative abundance 53.33%) and semi-intensive (relative abundance 59.2%) culture systems. Results indicated that the bacterial community structure was significantly ( ) distinct among gut, sediment, and water samples as well as the farming systems. The shared operational taxonomic unit (OTU) in the sediment sample (16,495) was nearly double than the gut (7,931) and water (8,513) bacterial communities. The improved extensive farming system showed 1,289 (11.05%) shared OTUs among gut, sediment, and water followed by semi-intensive (6.87%), cluster (6.27%), and extensive (5.46%) farming system. Among the tested ARGs, sul1, cat, gyrA(C), tetA, tetC, tetX, ere(A), vanR, and dfrA1 were predominant in water and sediment samples. Semi-intensive farming system had the highest prevalence of ARGs (21.05%) while the lowest prevalence was found in extensive (5.26%) farming system. Overall, the study provides a comprehensive scenario of bacterial composition and growing emergence of ARGs in shrimp farming of Bangladesh. Therefore, the production strategy must focus on the alternatives of antibiotic for shaping the shrimp cultivation technique more sustainable.

Culture fisheries contributes a major share of fisheries production of Bangladesh which is the accumulation of aquaculture production of every fish farms of the country. However, the actual production of cultured fish (finfish and shellfish) and cost-benefit of the farms are not well documented. Moreover, the farms must overcome a lot of constrains for sustainable production. The present study was thus designed to determine the present aquaculture status in some parts of Bangladesh and to identify the problems for the loss of aquaculture production through questionnaire survey between July 2019 and January 2020. The study areas included Bhola, Rangamati, Khulna, Satkhira, Jashore and Madaripur upazila. In the study area, the relationship between different aspects of aquaculture was determined where pond size and production cost per hectare; pond size and profit per hectare and per unit production cost and profit were found to be significantly and positively correlated. The production and production cost per hectare were also determined which were 3.52±0.40 metric tons and 6260±987 USD, respectively. The fish farmers reported some degrees of reduction of profits compare to the profit obtained during 2018-2019. The reduction of expected profit in different regions ranged between 10 and 33%. The major causes of the production loss in the survey regions were related to disease, seed and feed. Among different diseases viral, bacterial and parasitic diseases were reported where diseases were identified based on the symptoms. Findings of the present study suggest that incorporation of management, modern technology and economic aspects for steady growth of aquaculture sector is needed in Bangladesh. Dhaka Univ. J. Biol. Sci. 31(2): 257-271, 2022 (July)