Comparing Two Mycobacterium tuberculosis Genomes from Chinese Immigrants with Native Genomes Using Mauve Alignments.

BACKGROUND: The number of immigrants with tuberculosis (TB) increases each year in South Korea. Determining the transmission dynamics based on whole genome sequencing (WGS) to cluster the strains has been challenging. METHODS: WGS, annotation refinement, and orthology assignment for the GenBank accession number acquisition were performed on two clinical isolates from Chinese immigrants. In addition, the genomes of the two isolates were compared with the genomes of Mycobacterium tuberculosis isolates, from two native Korean and five native Chinese individuals using a phylogenetic topology tree based on the Multiple Alignment of Conserved Genomic Sequence with Rearrangements (Mauve) package. RESULTS: The newly assigned accession numbers for two clinical isolates were CP020381.2 (a Korean-Chinese from Yanbian Province) and CP022014.1 (a Chinese from Shandong Province), respectively. Mauve alignment classified all nine TB isolates into a discriminative collinear set with matched regions. The phylogenetic analysis revealed a rooted phylogenetic tree grouping the nine strains into two lineages: strains from Chinese individuals and strains from Korean individuals. CONCLUSION: Phylogenetic trees based on the Mauve alignments were supposed to be useful in revealing the dynamics of TB transmission from immigrants in South Korea, which can provide valuable information for scaling up the TB screening policy for immigrants.

Lessons learned from continued TB outbreaks in a high school.

We investigated the aftereffects of confirmatory QuantiFERON testing (QFT) added to a positive tuberculin skin test (TST). We reviewed the pre and post course of sequential tuberculosis (TB) outbreaks in a high school where massive 43 active TB cases had been found within one year before delayed contact investigation. And we investigated the TB development in relation to initial TST and QFT during mean follow-up of 3.9 ± 0.9 years. After delayed contact investigation for two subsequent TB outbreaks, 925 contacts were divided into the following 3 groups: TST- (n = 632), TST+/QFT+ (n = 24), TST+/QFT- (n = 258). QFT- was more prevalent than QFT+ in contacts with 10mm ≤ TST <15mm (158, 61.2%) compared with TST ≥15mm (100, 38.8%) among the TST+ reactors (P < 0.001). Among the 258 TST+/QFT- subjects, 256 received no latent TB infection (LTBI) treatment, but 7 contacts developed TB during follow-up. Among these 7 patients, 4 had initial TST ≥15mm and 3 had 10mm ≤ TST <15mm. In conclusion, the delayed contact investigation for LTBI in a high school resulted in continued TB developments. False-negative QFT performed late among the TST+ reactors should not be considered criteria for LTBI treatment. Additionally, the contacts only with TST ≥15mm should be considered for LTBI treatment in congregate settings of intermediate-burden countries.

Predictors and clinical outcomes of persistent methicillin-resistant Staphylococcus aureus bacteremia: a prospective observational study.

BACKGROUND/AIMS: The high mortality attributable to persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in spite of glycopeptide treatment has heightened the need for early detection and intervention with alternative agents. The purpose of this study was to determine the clinical characteristics of and risk factors for persistent MRSA bacteremia. METHODS: All first episodes of significant MRSA bacteremia at a 710-bed academic medical center from November 2009 through August 2010 were recorded. Blood cultures were conducted at 3 days and every 2 to 3 days thereafter until clearance. Clinical characteristics and outcomes were compared between persistent MRSA bacteremia (≥ 7 days) and nonpersistent MRSA bacteremia (≤ 3 days). RESULTS: Of 79 patients with MRSA bacteremia during the study period, 31 (39.2%) had persistent MRSA bacteremia. The persistent MRSA bacteremia group had significantly higher 30-day mortality than the nonpersistent MRSA bacteremia group (58.1% vs. 16.7%, p < 0.001). Multivariate analysis indicated that metastatic infection at presentation (odds ratio [OR], 14.57; 95% confidence interval [CI], 3.52 to 60.34; p < 0.001) and delayed catheter removal in catheter-related infection (OR, 3.80; 95% CI, 1.04 to 13.88; p = 0.004) were independent predictors of persistent MRSA bacteremia. Patients with a time to blood culture positivity (TTP) of < 11.8 hours were at increased risk of persistent MRSA bacteremia (29.0% vs. 8.3%, p = 0.029). CONCLUSIONS: High mortality in patients with persistent MRSA bacteremia was noted. Early detection of metastatic infection and early removal of infected intravascular catheters should be considered to reduce the risk of persistent MRSA bacteremia. Further studies are needed to evaluate the role of TTP for predicting persistent MRSA bacteremia.

Noncompaction of the myocardium coexistent with bronchiectasis and polycystic kidney disease.

Noncompaction of the ventricular myocardium (NCM) is a disorder of unknown aetiology characterised by numerous, prominent ventricular trabeculations and deep intertrabecular recesses. Polycystic kidney disease (PKD) is characterised by the formation of multiple cysts in the kidneys and liver and, less frequently, in the pancreas. Cardiovascular abnormalities in PKD involve hypertension, mitral valve prolapse, intracranial aneurysms and pulmonary abnormalities include primary ciliary dyskinesia and bronchiectasis. Several case reports have described the possible association between PKD and NCM. However, NCM, PKD and bronchiectasis have not previously been correlated. This is the first case of NCM coupled with PKD and bronchiectasis.

Esophageal achalasia compressing left atrium diagnosed by echocardiography using a liquid containing carbon dioxide in a 21-year-old woman with Turner syndrome.

Extrinsic compression of the left atrium by the esophagus, the stomach, or both is an uncommon but important cause of hemodynamic compromise. Achalasia is a motility disorder characterized by impaired relaxation of the lower esophageal sphincter and dilatation of the distal two thirds of the esophagus. Echocardiographic imaging after oral ingestion of liquid containing carbon dioxide allowed for differentiation between a compressive vascular structure and the esophagus. We report a rare case of esophageal achalasia compressing the left atrium diagnosed by echocardiography using a liquid containing carbon dioxide in a 21-year-old woman with Turner syndrome.

Rare case of an unroofed coronary sinus.

Unroofed coronary sinus (CS) is a rare congenital cardiac anomaly described by a communication between the CS and the left atrium due to the partial or complete absence of the CS roof. Echocardiography is the most widely used imaging modality for suspected unroofed CS, but it is limited in its ability to visualize the posterior cardiac structures. Multidetector computed tomography has allowed the visualization and accurate anatomic and morphologic evaluation of these structures. We report a rare case of unroofed CS found incidentally in a 41-year-old man who was studied by echocardiography and multidetector computed tomography.