Vibrio parahaemolyticus is a significant causal agent of acute hepatopancreatic necrosis disease (AHPND), with huge production losses of white leg shrimp, Litopenaeus vannamei, cultivated globally, including aquaculture farms in the Mekong Delta of Vietnam. Controlling this disease is critical because of the worldwide expansion of antimicrobial‐resistant V. parahaemolyticus isolates. The purpose of this study was to determine the frequency of multi‐antibiotic resistance (MAR) in V. parahaemolyticus isolated from AHPND white leg shrimp extensively cultivated in Bac Lieu Province (Mekong Delta). Based on biochemical tests and toxR‐PCR positive detections, 34 V. parahaemolyticus isolates were identified. Antibiotic susceptibility examination revealed that most of the isolates were phenotypically multidrug resistant, including resistance to ceftazidime (100%) and amoxicillin (97.06%), followed by colistin (74%) and erythromycin (65%). These isolates were highly sensitive to doxycycline (94%), followed by florfenicol (74%) and flumequine (71%). There were 27 distinct MAR phenotypes detected among 34 isolates, with 14.71% of the isolates exhibiting the antibiotic profile AMO‐CEF‐CEP‐COL‐ERY, followed by 11.76% for each of the profiles AMO‐CEP‐TET‐COL and AMO–CEP–COL. In particular, 25 isolates (75%) were resistant to at least 5 (of the 12) antibiotics tested. A hierarchical clustering analysis of antibiotic‐resistant V. parahaemolyticus isolates indicated cross‐transmission across farms and its ability to survive in aquatic environments for extended periods (over 3 months). Our findings support the hypothesis that the variety of MARPs in V. parahaemolyticus is the result of human activities. Environmentally friendly therapy strategies should be used for the prophylaxis and treatment of V. parahaemolyticus infection.

Antimicrobial resistance from bacterial pathogens is becoming a health concern in many countries. The purpose of this investigation was to assess antimicrobial resistance and find out the prevalence of class 1 integrons from A. hydrophila that led to hemorrhagic disease in intensively farmed Tra catfish in the Mekong Delta, Vietnam. The research showed that a total of 74 isolates were isolated and identified as A. hydrophila by the API 20E kit and using the amplification products of the aerolysin gene for confirmation. The susceptibility of all isolates was tested against fifteen antimicrobial agents using the disk diffusion method. Our study indicated that most strains were resistant to the following antibiotics: trimethoprimsulfamethoxazole, ampicillin, cefalexin, tetracycline, amoxicillin, chloramphenicol, florfenicol, neomycin, and gentamycin. In addition, the investigation also indicated that most A. hydrophila isolates displayed multiple antibiotic resistance phenotypes. The MAR (multiple antibiotic resistance) index was high, ranging from 0.40 to 0.66 for A. hydrophila isolates, which indicated that these isolates were exposed to high risk sources of contamination where antibiotics were commonly used. Among all isolates, 12.16% (9/74 isolates) of class 1 integrons were determined by polymerase chain reaction

Genetic variability and correlation analysis are fundamental references for the innovative development of breeding programs to improve varieties and desirable traits. In the present study, the correlation and path analysis was conducted to understand the association among yield, micronutrients (iron and zinc), and protein content under aerobic conditions in local rice landraces from various agro ecological regions of Karnataka, India. The grain yield per plant showed a significant positive correlation with plant height, the tiller number, spikelet fertility, flag leaf length, and test weight. The zinc content was negatively correlated with grain yield per plant. The phenotypic path-coefficient analysis revealed that the total number of tillers, grain length, test weight, and harvest index exhibited a positive direct effect on grain yield per plant, while Grain protein content showed a low direct effect on this trait. This study also indicated that harvest index, flag leaf length, spikelet fertility, and test weight could be considered to make for a higher yield.

Tóm tắt: Nghiên cứu được thực hiện với mục tiêu khảo sát sự hiện diện và đặc điểm vùng gen cassette của các integron ở vi khuẩn Edwardsiella ictaluri gây bệnh gan thận mủ (GTM) trên cá tra nuôi thâm canh ở Đồng bằng sông Cửu Long (ĐBSCL). Bằng kỹ thuật PCR và giải trình tự gen, kết quả bài báo đã xác định 24/67 (chiếm tỷ lệ 35,82%) chủng vi khuẩn E. ictaluri dương tính với các integron nhóm 1. Trong khi đó, các integron nhóm 2 và 3 thì không được phát hiện ở tất cả các chủng vi khuẩn. Ngoài ra, nghiên cứu cũng đã xác định 7 vùng gen cassette với các kích thước là 0,65 kbp, 0,8 kbp, 0,95 kbp, 1,0 kbp, 1,2 kbp, 1,5 kbp và 2,5 kbp mã hóa cho các enzyme dihydrofolate reductase, aminoglycoside adenyltransferase, aminoglycoside N(6')-acetyltransferase và β-lactamase kháng lại nhiều loại kháng sinh khác nhau ở vi khuẩn E. ictaluri. Sự hiện diện của các integron nhóm 1 ở vi khuẩn E. ictaluri cho thấy khả năng vi khuẩn này có thể truyền gen kháng kháng sinh sang các loài vi khuẩn khác trong môi trường tự nhiên.