Integrative Analysis of Human Macrophage Inflammatory Response Related to Mycobacterium tuberculosis Virulence

Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, kills 1.5 to 1.7 million people every year. Macrophages are Mtb's main host cells and their inflammatory response is an essential component of the host defense against Mtb. However, Mtb is able to circumvent the macrophages' defenses by triggering an inappropriate inflammatory response. The ability of Mtb to hinder phagolysosome maturation and acidification, and to escape the phagosome into the cytosol, is closely linked to its virulence. The modulation of the host inflammatory response relies on Mtb virulence factors, but remains poorly studied. Understanding macrophage interactions with Mtb is crucial to develop strategies to control tuberculosis. The present study aims to determine the inflammatory response transcriptome and miRNome of human macrophages infected with the virulent H37Rv Mtb strain, to identify macrophage genetic networks specifically modulated by Mtb virulence. Using human macrophages infected with two different live strains of mycobacteria (live or heat-inactivated Mtb H37Rv and M. marinum), we quantified and analyzed 184 inflammatory mRNAs and 765 micro(mi)RNAs. Transcripts and miRNAs differently modulated by H37Rv in comparison with the two other conditions were analyzed using in silico approaches. We identified 30 host inflammatory response genes and 37 miRNAs specific for H37Rv virulence, and highlight evidence suggesting that Mtb intracellular-linked virulence depends on the inhibition of IL-1β-dependent pro-inflammatory response, the repression of apoptosis and the delay of the recruitment and activation of adaptive immune cells. Our findings provide new potential targets for the development of macrophage-based therapeutic strategies against TB.

Salmonella outbreak in an American child development center in Germany

In July 1993, an outbreak of Salmonella occurred in a U.S. Army child care center in Heidelberg, Germany. Sixteen children and 4 staff members had confirmed positive cultures; the center had an average census of 135 children during the time of the outbreak. Rectal swabs were done on all the children in rooms with symptomatic children or staff or in rooms with confirmed cases. A total of 246 rectal swabs was done initially, with 216 representing paired specimens. A case was defined as a staff member, child, or family member of an ill staff member or child who attended the center with diarrhea or abdominal pain with at least one of the following symptoms: diarrhea, fever, nausea, loss of appetite, abdominal pain, vomiting, or lethargy. The attack rate for the children was 40 of 86 (47%), and the attack rate for staff was 15 of 47 (32%). No associations were found when looking at the attack rates in each of the 10 rooms in the center. Complete environmental investigation revealed that the cook was preparing food 1 day before it was served. In addition, he was running the dishwasher without a sufficient amount of soap. Although food was not available for testing, the source of the Salmonella outbreak appears to be uncooked or inadequately cooked and prepared food with some person-to-person transmission.

Early single-photon emission computed tomography in mild head trauma. A controlled study

Although computed tomography (CT) and magnetic resonance imaging scans often appear normal after mild head trauma, many patients experience attentional or other cognitive disturbances that are difficult to quantify by neuropsychological testing in the absence of a premorbid profile. Within 2 days of mild head trauma, 14 patients with normal-appearing brain CTs were studied with single-photon emission computed tomography (SPECT). They were compared to 15 normal control subjects and to 12 patients with mild human immunodeficiency virus (HIV) encephalopathy. Ten of 14 head trauma patients were separated from the normal control subjects by both independent readers, blinded to the clinical diagnosis. None of the SPECT results from normal control subjects were "read" as trauma. Trauma could not be differentiated from HIV encephalopathy. The observed percentage agreement between raters was 0.83 (kappa = 0.72). SPECT is more sensitive than CT in detecting brain injury after mild head trauma.