Necrotizing staphylococcal pneumonia in a neonate.

Hospitalized neonates are commonly colonized soon after birth with Staphylococcus aureus. The majority of neonates do not develop infectious sequelae; however, premature neonates appear to be more susceptible to serious infections, such as pneumonia. We report a case of an extremely low birth weight infant who developed necrotizing pneumonia due to methicillin-resistant Staphylococcal aureus (MRSA). The MRSA isolate from this neonate is identical to the strains that have been causing primarily community-associated skin and soft tissue infections. The severe course of this patient may be attributed to the presence of the Panton-Valentine leukocidin gene, a well-known virulence factor leading to soft tissue and pulmonary infections

Trends in Well-Child Visits and Routine Vaccination among Children of U.S. Military Members: An Evaluation of the COVID-19 Pandemic Effects

The COVID-19 pandemic has drastically impacted administration of healthcare including well-child visits and routine vaccinations. The purpose of this study was to determine the impact of COVID-19 pandemic disruption on childhood health maintenance: well-child visits and scheduled vaccinations. We queried the TRICARE Management Activity’s Military Health System (MHS) database for outpatient well-child visits and vaccinations for all children 0 to 23 months of age eligible for TRICARE healthcare. The median rate of well-child visits, during the COVID-19 period (March 2020–July 2021), was significantly declined for all demographic groups: all ages, parental military ranks, sex, and regions as compared to the pre-COVID-19 period (February 2019–February 2020). Similar to rates of well-child visits, the rate of vaccinations declined during the COVID-19 period as compared to the pre-COVID-19 period for all demographic groups, except children 12–23 months. Rates of well-child visits for military dependent children under 2 years of age were decreased during the 16 month COVID-19 period, with large increases seen in the first 2 months of the pandemic; the consequences of missed well-child visits and vaccination are unknown

<i>L. sigmodontis</i> co-infection does not increase <i>M. tuberculosis</i> burden in lung or spleen and does not exacerbate lung granuloma formation.

<p><i>A</i>, Percentage of lung area covered with granulomas. <i>B</i>, <i>M. tuberculosis</i> colony-forming units (CFU) in lung and <i>C</i>, spleen. Cotton rats were infected with <i>L. sigmodontis</i> (L.s.) and/or <i>M. tuberculosis</i> (MTB), or were uninfected. Shown are representative results from one of two experiments. Statistical significance between co-infected and MTB-only infected groups was analyzed by the Mann-Whitney-U-test.</p

Chronic <i>L. sigmodontis</i> infection induces eosinophilia and a hyporesponsive milieu.

<p><i>A</i>, peripheral blood eosinophil counts from uninfected, 5, and 11 week-<i>Litomosoides sigmodontis</i> (L.s.) infected cotton rats. In vitro spleen cell proliferation (<i>B</i>, <i>C</i>, as proliferation index (OD of stimulated cells/baseline)) and IFNγ production (<i>D</i>, <i>E</i>) in response to <i>L. sigmodontis</i> antigen (LsAg) or <i>Staphylococcal</i> enterotoxin B (SEB) from cotton rats that were either uninfected or infected with <i>L. sigmodontis</i> for 5 or 11 weeks. Statistical significance between groups was analyzed by the Kruskal-Wallis test, followed by Dunn's post-hoc multiple comparisons. Single stars show significant differences compared to uninfected animals. *p<0.05.</p

PPD-specific proliferation is not impaired by <i>L. sigmodontis</i> co-infection.

<p><i>A</i>, Spleen cell proliferation in response to <i>M. tuberculosis</i> PPD and <i>B</i>, SEB. Cotton rats were infected with <i>L. sigmodontis</i> (L.s.) and/or <i>M. tuberculosis</i> (MTB), or were uninfected. Shown is the proliferation index (OD of stimulated cells/baseline). Statistical significance between groups were analyzed by the Kruskal-Wallis test, followed by Dunn's post-hoc multiple comparisons. Single stars show significant differences compared to the uninfected animals. Shown are representative results from one of two experiments. **p<0.01, ***p<0.001.</p

<i>M. tuberculosis</i> infection has no consistent impact on <i>L. sigmodontis</i> worm burden.

<p><i>A</i>, total number of <i>L. sigmodontis</i> adult worms recovered from the pleural space and <i>B</i>, number of microfilaria per µl of peripheral blood of cotton rats that were infected with <i>L. sigmodontis</i> (L.s.) and <i>M. tuberculosis</i> (MTB) or <i>L. sigmodontis</i> alone (20 weeks post <i>L. sigmodontis</i> infection) from the first experiment. <i>C</i>, total number of <i>L. sigmodontis</i> adult worms recovered from the pleural space of the repeat experiment. Statistical significance was analyzed by the Mann-Whitney-U-test.</p

Histological assessment of <i>L. sigmodontis</i> and <i>M. tuberculosis</i> infection at the 20 week timepoint.

<p><i>A</i>, lung with <i>M. tuberculosis</i> (MTB) granulomas obtained from a co-infected animal 9 weeks post MTB challenge (the 20 week timepoint). <i>B</i>, Lung granuloma (red arrow) with central necrosis (green arrow) observed in the lung of a cotton rat infected with MTB (H&E, 40×). <i>C</i>; Acid-fast stain of MTB bacteria in the lung (100×). <i>D</i>, <i>L. sigmodontis</i> microfilaria in peripheral blood (Eosin-Y Azure A Methylene Blue, 100×). <i>E</i>, H&E stained cross-section of lung tissue that shows a <i>L. sigmodontis</i> adult worm in the pleural space adjacent to the lung (40×).</p

PPD-specific IFNγ production is not reduced by <i>L. sigmodontis</i> co-infection.

<p><i>A</i>, IFNγ production of spleen cells in response to <i>M. tuberculosis</i> PPD and (<i>B</i>), SEB. Cotton rats were infected with <i>L. sigmodontis</i> (L.s.) and/or <i>M. tuberculosis</i> (MTB), or were uninfected. Statistical significance between groups was analyzed by the Kruskal-Wallis test, followed by Dunn's post-hoc multiple comparisons. Shown are representative results from one of two experiments. Single stars show significant differences compared to the uninfected animals. **p<0.01, ***p<0.001.</p