Rationale: Drug-resistant tuberculosis transmission in hospitals threatens staff and patient health. Surgical face masks used by patients with tuberculosis (TB) are believed to reduce transmission but have not been rigorously tested. Objectives: We sought to quantify the efficacy of surgical face masks when worn by patients with multidrug-resistant TB (MDR-TB). Methods: Over 3 months, 17 patients with pulmonary MDR-TB occupied an MDR-TB ward in South Africa and wore face masks on alternate days. Ward air was exhausted to two identical chambers, each housing 90 pathogen-free guinea pigs that breathed ward air either when patients wore surgical face masks (intervention group) or when patients did not wear masks (control group). Efficacy was based on differences in guinea pig infections in each chamber. Measurements and Main Results: Sixty-nine of 90 control guinea pigs (76.6%; 95% confidence interval [CI], 68-85%) became infected, compared with 36 of 90 intervention guinea pigs (40%; 95% CI, 31-51%), representing a 56% (95% CI, 33-70.5%) decreased risk of TB transmission when patients used masks. Conclusions: Surgical face masks on patients with MDR-TB significantly reduced transmission and offer an adjunct measure for reducing TB transmission from infectious patients.Keywords: infection control; multidrug-resistant tuberculosis; transmission; surgical maskOf an estimated 9 million new cases of tuberculosis (TB) in 2008 globally (1), 440,000 were multidrug-resistant TB (MDR-TB) (2), and more than half of those are believed to have occurred in previously untreated patients, the result of transmission of already drug-resistant strains (2). Recent reports of infection with highly drug-resistant strains of Mycobacterium tuberculosis among patients and health care workers illustrate the dire consequences of nosocomial transmission, especially in areas where HIV is endemic (3, 4). Although once believed to arise primarily from unsupervised or erratic treatment of drug-susceptible TB, MDR-TB and extensively drug-resistant TB (XDR-TB) are now known to be transmissible and have emerged as important threats to patients who enter hospitals for drug-susceptible TB (reinfection) or other illnesses, to the clinical staff caring for them, and to occupants of other congregate settings, such as correctional facilities and shelters. One study in Russia found that hospitalization, rather than treatment nonadherence, conferred a sixfold greater relative risk for the acquisition of MDR-TB by patients (5), whereas another study in Latvia revealed that previous hospitalization was a highly significant risk factor for MDR-TB (odds ratio, 18.33; P , 0.002) (6). In addition, health care workers in diverse settings have been shown to be disproportionately exposed to and infected with drugsusceptible and drug-resistant TB (4, 7). TB among health care workers erodes the already limited supply of hospital personnel in many resource-constrained settings, both directly through illness and indirectly through fear of working in such high-risk envi...

Background The COVID-19 pandemic is disrupting normal life globally, every area of life is touched. The pandemic demands quick action and as new information emerges, reliable synthesises and guidelines for care are urgently needed. Breastfeeding protects mother and child; its health benefits are undisputed and based on evidence. To plan and support breastfeeding within the current pandemic, two areas need to be understood: 1) the clinical characteristics of COVID-19 as it applies to breastfeeding and 2) the protective properties of breastfeeding, including the practice of skin-to-skin care. This review aims to summarise how to manage breastfeeding during COVID-19. The summary was used to create guidelines for healthcare professionals and mothers. Methods Current publications on breastfeeding during the COVID-19 pandemic were reviewed to inform guidelines for clinical practice. Results Current evidence states that the Coronavirus is not transmitted via breastmilk. Breastfeeding benefits outweigh possible risks during the COVID-19 pandemic and may even protect the infant and mother. General infection control measures should be in place and adhered to very strictly. Conclusions Breastfeeding should be encouraged, mothers and infant dyads should be cared for together, and skin-to-skin contact ensured throughout the COVID-19 pandemic. If mothers are too ill to breastfeed, they should still be supported to express their milk, and the infant should be fed by a healthy individual. Guidelines, based on this current evidence, were produced and can be distributed to health care facilities where accessible information is needed.

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Activation of the adrenergic nervous system appears to play a crucial role in the genesis of fatal arrhythmias associated with the very early stages of acute myocardial infarction. The second messenger of beta-adrenergic catecholamine stimulation, cyclic adenosine monophosphate (AMP), has established arrhythmogenic qualities, acting by an increase in cytosolic calcium, which potentially has three adverse electrophysiologic effects. First, stimulation of the transient inward current by excess oscillations of cytosolic calcium can invoke delayed afterdepolarizations, so that triggered automaticity can develop in otherwise quiescent ventricular muscle. Second, cyclic AMP can evoke calcium-dependent slow responses in depolarized fibers, so that conditions for reentry are favored. Third, excess cytosolic calcium can cause intercellular uncoupling with conduction slowing. Focal changes in cyclic AMP and cytosolic calcium promote the development of ventricular fibrillation. Beta-adrenergic blockade can limit the formation of cyclic AMP in ischemic tissue. Furthermore, by reducing sinus tachycardia it can lessen cytosolic calcium overload. Hence, beta-adrenergic blockade helps to prevent ventricular fibrillation in the early stages of acute myocardial infarction and protects from sudden death in the postinfarction phase. In congestive heart failure, abnormalities of cytosolic calcium patterns exist with cytosolic calcium overload. It is proposed that the adverse effects of phosphodiesterase inhibitors on the mortality rate in patients with congestive heart failure can be explained by increased rates of formation of cyclic AMP and the development of calcium-dependent arrhythmias. Because calcium is the ultimate messenger of cyclic AMP-induced arrhythmias and because cytosolic calcium is increased in heart failure, it will be difficult to develop positive inotropic agents that are free of the risk of sudden death.

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