This study was conducted to estimate the prevalence of Salmonella spp. and their antimicrobial susceptibilities on poultry and swine farms, sampled in 2 regions in Central Vietnam. A total of 67 poultry farms and 46 swine farms were sampled in a period of 5 months (from September 2012 to January 2013). Salmonella spp. was prevalent in 46.3% and 71.7% of poultry and swine farms, respectively. Altogether, 99 non-typhoidal Salmonella were isolated and the most common serovars were Salmonella Weltevreden (19%), followed by Salmonella Typhimurium (12%) and Salmonella 4,[5],12:i:- (11%). Overall, 71 of 99 (72%) Salmonella isolates were resistant to at least one of the 14 antimicrobial agents tested. Both in poultry and swine farms, high levels of resistance were observed for ampicillin, chloramphenicol, ciprofloxacin, sulphamethoxazole and tetracycline. The presence of Salmonella isolates from poultry and swine farms which were resistant to different classes of antimicrobials suggests that alternative control measures to antimicrobials should be implemented. Moreover, an effective policy should be promoted to encourage a prudent use of these agents in animal farming in Vietnam.

Healthcare workers are among the most at-risk groups to get infected by SARS-CoV-2 due to the exposure to disease sources in specific working environment. However, after experiencing four waves of epidemics, there was a certain proportion of healthcare workers who have ever been diagnosed to be infected with SARS-CoV-2, regardless of whether they have a history of contact with or an unknown history of contact with an unidentified source of infection. This research aimed to identify the characteristics of healthcare workers who have not diagnosed with SARS-CoV-2 or have never been infected by SARS-CoV-2. 79 staffs of Hanoi Medical University were selected at the time of April 2022. 16 out of 79 individuals were infected with SARS-CoV-2 but had not been identified. 50% of this group were physicians working at primary care unit. Subjects who had been infected by SARS-CoV-2 showed greater levels of anti-receptor-binding domain (RBD) of SARS-CoV-2 antibodies than those who had never been infected (p=0.001). Anti-RBD antibody levels in 93.67% of research individuals were above the FDA-recommended threshold of 4.8 U/mL for the use of convalescent plasma. In the group that had never been infected by SARS-CoV-2, the antibody levels against RBD-SARS-CoV-2 were lower in those vaccinated above 90 days than those vaccinated below 90 days (p=0.02). 20.25% of research subjects who had never been diagnosed had infected by SARS-CoV-2, with greater levels of anti-RBD-SARS-CoV-2 antibodies than the uninfected group. In the uninfected group, antibody levels gradually decreased over time.

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