Stringent nonpharmaceutical interventions (NPIs) such as lockdowns and border closures are not currently recommended for pandemic influenza control. New Zealand used these NPIs to eliminate coronavirus disease 2019 during its first wave. Using multiple surveillance systems, we observed a parallel and unprecedented reduction of influenza and other respiratory viral infections in 2020. This finding supports the use of these NPIs for controlling pandemic influenza and other severe respiratory viral threats.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that can detect bacteria-derived metabolites presented on MR1. Here we show, using a controlled infection of humans with live Salmonella enterica serovar Paratyphi A, that MAIT cells are activated during infection, an effect maintained even after antibiotic treatment. At the peak of infection MAIT cell T-cell receptor (TCR)β clonotypes that are over-represented prior to infection transiently contract. Select MAIT cell TCRβ clonotypes that expand after infection have stronger TCR-dependent activation than do contracted clonotypes. Our results demonstrate that host exposure to antigen may drive clonal expansion of MAIT cells with increased functional avidity, suggesting a role for specific vaccination strategies to increase the frequency and potency of MAIT cells to optimize effector function.

cCorynebacterium species are increasingly recognized as important pathogens in granulomatous mastitis. Currently, there are no published treatment protocols for Corynebacterium breast infections. This study describes antimicrobial treatment options in the context of other management strategies used for granulomatous mastitis. Corynebacterium spp. isolated from breast tissue and aspirate samples stored from 2002 to 2013 were identified and determined to the species level using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), 16S RNA sequencing, and rpoB gene targets. The MICs for 12 antimicrobials were performed using Etest for each isolate. Correlations of these with antimicrobial characteristics, choice of antimicrobial, and disease outcome were evaluated. Corynebacterium spp. from breast tissue and aspirate samples were confirmed in 17 isolates from 16 patients. Based on EUCAST breakpoints, Corynebacterium kroppenstedtii isolates (n ‫؍‬ 11) were susceptible to seven antibiotic classes but resistant to ␤-lactam antibiotics. Corynebacterium tuberculostearicum isolates (n ‫؍‬ 4) were multidrug resistant. Two nonlipophilic species were isolated, Corynebacterium glucuronolyticum and Corynebacterium freneyi, both of which have various susceptibilities to antimicrobial agents. Short-course antimicrobial therapy was common (median, 6 courses per subject; range, 1 to 9 courses). Patients with C. kroppenstedtii presented with a hot painful breast mass and underwent multiple surgical procedures (median, 4 procedures; range, 2 to 6 procedures). The management of Corynebacterium breast infections requires a multidisciplinary approach and includes culture and appropriate sensitivity testing to guide antimicrobial therapy. Established infections have a poor outcome, possibly because adequate concentrations of some drugs will be difficult to achieve in lipophilic granulomata. Lipophilic antimicrobial therapy may offer a therapeutic advantage. The role of immunotherapy has not been defined. Granulomatous mastitis (GM) is a rare inflammatory condition that typically occurs in parous women of reproductive age (1). Clinically, it can present as a breast mass with features similar to those of breast malignancy (2). Multiple infective and inflammatory conditions, including tuberculosis (TB), fungal infections, sarcoidosis, amyloidosis, and Wegener's granulomatosis, have been recognized, but recently, attention has been drawn to corynebacterial species as a specific pathogen in this disease. Typically, corynebacterial breast infections are characterized by abscess formation, granulomatous inflammation, and progression to sinus/fistula formation (3). This and other specific diagnoses should be excluded before a diagnosis of idiopathic granulomatous mastitis (IGM) is made (3-5).Commonly, it is the lipophilic species of the Corynebacterium genus that cause mastitis (3, 6-8). As such, a microbiological diagnosis can be challenging, due to their fastidious growth requirements and prolonged incu...

SummaryThe safe establishment of a protocol for a human challenge model for Salmonella Paratyphi A can be used to expedite the evaluation of novel vaccine candidates and provides insight into the clinical and immune response to paratyphoid infection.