Tetracycline-resistant bacteria were first isolated in 1953 from Shigella dysenteriae, a bacterium which causes bacterial dysentery. Since then tetracycline-resistant bacteria have been found in increasing numbers of species and genera. This has resulted in reduced effectiveness of tetracycline therapy over time. Tetracycline resistance is normally due to the acquisition of new genes often associated with either a mobile plasmid or a transposon. These tetracycline resistance determin~mts are distinguishable both genetically and biochemically. Resistance is primarily due to either energy-dependent efflux Of tetracycline or protection of the ribosomes from the action of tetracycline. Gram-negative tetracycline efflux proteins are linked to repressor proteins which in the absence of tetracycline block transcription of the repressor and structural effiux genes. In contrast, expression of the Gram-positive tetracycline efflux genes and some of the ribosomal protection genes appears to be regulated by attenuation of mRNA transcription. Specific tetracycline resistance genes have been identified in 32 Gram-negative and 22 Gram-positive genera, Tetracycline-resistant bacteria are found in pathogens, opportunistic and normal flora species. Tetracycline-resistant bacteria can be isolated from man, animals, food, and the environment. The nonpathogens in each of these ecosystems may play an important role as reservoirs for the antibiotic resistance genes. It is clear that if we are to reverse the trend toward increasingly antibiotic-resistant pathogenic bacteria we will need to change how antibiotics are used in both human and animal health and food production.

HZ incidence in vaccinated children was 79% lower than in unvaccinated children. Among vaccinated children, half of HZ cases were due to wild-type VZV.

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Social disruption caused by natural disasters often interrupts educational opportunities for children. However, little is known about children's learning in the following years. This study examined change in academic scores for children variably exposed to a major bushfire in Australia. Comparisons were made between children attending high, medium, and low disaster‐affected primary schools 2–4 years after the disaster (n = 24,642; 9–12 years). The results showed that in reading and numeracy expected gains from Year 3 to Year 5 scores were reduced in schools with higher levels of bushfire impact. The findings highlight the extended period of academic impact and identify important opportunities for intervention in the education system to enable children to achieve their academic potential.

Background: People living with MS during COVID-19 are experiencing the disruptions of the pandemic and concerns that their health status may place them at greater risk for worse COVID-19 outcomes.Objective: This study sought to understand how people living with MS in the United States experienced distress and perceived their COVID-19-related risk during the first surge of the pandemic. Methods: This was a web-based, self-report survey of people with MS who were living in the United States during the early stage of COVID-19. Primary outcomes were depression, anxiety, and positive-affect and well-being. Participants (N = 491) also provided data on demographics, MS-related factors, COVID-19 factors, and psychological coping. Results: Psychological distress was associated with age, psychological coping strategies, and having had symptoms consistent with COVID-19, but not with MS disease-related variables and COVID-19 risk factors. Perception of COVID-19-related risk was associated with age, MS disease severity, COVID-19-related factors, and anxiety. Conclusion:This study demonstrated that even during COVID-19, distress and risk perception are primarily driven by psychological factors, experiencing symptoms consistent with COVID-19 and age, with minimal contribution from individual differences in health status, providing an impetus for continued efforts to optimize psychological interventions for people living with MS.