Spatial Epidemiologic Analysis and Risk Factors for Nontuberculous Mycobacteria Infections, Missouri, USA, 2008–2019

Nontuberculous mycobacteria (NTM) infections are caused by environmental exposure. We describe spatial distribution of NTM infections and associations with sociodemographic factors and flooding in Missouri, USA. Our retrospective analysis of mycobacterial cultures reported to the Missouri Department of Health and Social Services surveillance system during January 1, 2008–December 31, 2019, detected geographic clusters of infection. Multilevel Poisson regression quantified small-area geographic variations and identified characteristics associated with risk for infection. Median county-level NTM infection rate was 66.33 (interquartile range 51–91)/100,000 persons. Risk of clustering was significantly higher in rural areas (rate ratio 2.82, 95% CI 1.90–4.19) and in counties with >5 floodings per year versus no flooding (rate ratio 1.38, 95% CI 1.26–1.52). Higher risk for NTM infection was associated with older age, rurality, and more flooding. Clinicians and public health professionals should be aware of increased risk for NTM infections, especially in similar environments

Hierarchical clustering of genes expressed more than A) 10-fold and B) 50-fold in oral and skin epithelium.

<p>The heatmap indicates gene expression in the skin and oral epithelium is significantly different. The color key shows the assignment of color to the expression intensity value. FDR<0.01, N = 4. The clustering is based on hierarchical clustering with squared Euclidean distance between the samples and complete linkage. The heatmaps were generated using package "gplots” in R (<a href="http://www.r-project.org" target="_blank">http://www.r-project.org</a>).</p

Comparison of skin and oral keratinocyte proliferation after <i>In Vitro</i> wounding.

<p>Isolated primary paired human keratinocytes (skin and hard palate) were cultured for <i>In Vitro</i> scratch assays. Keratinocyte proliferation was measured at time points of 0, 24, and 48 hours post scratch with CellTiter96 Aqueous One Solution Cell Proliferation Assay. Proliferation ratio was determined by the formula: OD_{X hrs post-scratch}/OD_{0 hrs post-scratch}. OD was read at an absorbance of 490 nm. 24 hours post scratch skin 1.190±0.03 vs oral 1.413± 0.02; 48 hours post scratch skin 1.370±0.02 vs oral 1.408±0.01 * p<0.05 by two-way ANOVA and Bonferroni post-test in skin vs oral wounds. N = 3. *Compared to 24 hr skin.</p

Intrinsic Differences between Oral and Skin Keratinocytes

<div><p>Keratinocytes cover both the skin and some oral mucosa, but the morphology of each tissue and the behavior of the keratinocytes from these two sites are different. One significant dissimilarity between the two sites is the response to injury. Oral mucosal wounds heal faster and with less inflammation than equivalent cutaneous wounds. We hypothesized that oral and skin keratinocytes might have intrinsic differences at baseline as well as in the response to injury, and that such differences would be reflected in gene expression profiles.</p></div