Beijing and Haarlem genotypes are overrepresented among children with drug-resistant tuberculosis in the Western Cape Province of South Africa

Drug resistance among children with culture-confirmed tuberculosis (TB) provides an accurate measure of transmitted drug resistance within the community. We describe the genotype diversity in children with culture-confirmed TB and investigate the relationship between genotype and drug resistance. A prospective study was conducted from March 2003 through August 2005 at Tygerberg Children's Hospital, in the Western Cape Province of South Africa. All children (<13 years of age) diagnosed with culture-confirmed TB were included. Genotype analysis and phenotypic drug susceptibility testing were performed on the first culture-positive isolate from each patient. Mutation analysis was performed on all drug-resistant isolates. Spoligotyping was successfully performed on isolates from 391/399 (98%) children diagnosed with culture-confirmed TB. Drug susceptibility testing was also performed on 391 isolates; 49 (12.5%) were resistant to isoniazid, and 20 (5.1%) of these were resistant to both isoniazid and rifampin. Beijing was the most common genotype family, identified in 130/391 (33.2%) cases, followed by LAM in 114/391 (29.2%) cases. The presence of both Beijing and Haarlem genotype families was significantly associated with drug resistance (26/49 [53.1%] versus 113/342 [33.0%]; odds ratio, 1.7; 95% confidence interval, 1.0 to 2.9). The high prevalence of Beijing and LAM in children with culture-confirmed TB reflects considerable transmission of these genotype families within the community. The overrepresentation of Beijing and Haarlem genotype families in children with drug-resistant TB demonstrates their contribution to transmitted drug resistance and their potential importance in the emergent drug-resistant TB epidemic.     

Inflamed fibronectin: an altered fibronectin enhances neutrophil adhesion

Recent investigations have emphasized the role of activated granulocytes in mediating vascular endothelial injury in the pathogenesis of shock lung. In vitro studies have indicated that tight adherence of the neutrophil to the endothelium is crucial for the development of cellular injury. Fibronectin is critical to cell-to- substratum and cell-to-cell interactions. Since fibronectin resides in plasma, on endothelial cell surfaces and is secreted into cell matrices, the adhesive properties of fibronectin must be modulated, lest universal cell agglomeration occur, yet be enhanced when cell attachment is appropriate. In these studies, treatment of fibronectin- coated surfaces with neutrophil release products increased the adhesion of activated neutrophils. Similarly, endothelial cells treated with neutrophil release products become a more adherent substrate for neutrophils. This enhanced adherence generated by treatment of fibronectin with neutrophil supernatants is inhibitable by heat and the lysosomal proteinase inhibitor, pepstatin-A. Neutrophil release products cause proteolytic fragmentation of fibronectin and enhanced fibronectin immunofluorescence on endothelial cells. In addition, neutrophils are more injurious to endothelial cells that have been pretreated with neutrophil release products. Neutrophils may enhance their own adherence to endothelial cells by altering fibronectin, and this altered, or "inflamed," fibronectin may serve as an amplifier of inflammation.     

Trends in preterm birth in singleton deliveries in a Hong Kong population

Objective

To examine trends in preterm birth and its relationship with perinatal mortality in Hong Kong.

Methods

In a retrospective cohort study, data were reviewed from singletons delivered between 1995 and 2011 at a university teaching hospital. Trends in preterm birth (between 24 and 36 weeks of pregnancy), perinatal mortality, and subtypes of preterm birth (spontaneous, iatrogenic, and following preterm premature rupture of membranes [PPROM]) were examined via linear regression.

Results

There were 103 364 singleton deliveries, of which 6722 (6.5%) occurred preterm, including 1835 (1.8%) early preterm births (24–33 weeks) and 4887 (4.7%) late preterm births (34–36 weeks). Frequency of preterm birth remained fairly consistent over the study period, but that of spontaneous preterm birth decreased by 25% (β = –0.83; P < 0.001), from 4.5% to 3.8%. Frequency of preterm birth following PPROM increased by 135% (β = 0.82; P < 0.001), from 0.7% to 1.7%. The perinatal mortality rate decreased from 56.7 to 37.0 deaths per 1000 deliveries before 37 weeks (β = –0.16; P = 0.54). Early preterm birth contributed to 16.0% of all deaths.

Conclusion

Although the overall rate of preterm birth in Hong Kong has remained constant, the frequencies of its subtypes have changed. Overall perinatal mortality is gradually decreasing, but early preterm birth remains a major contributor.     

Neurohydatidosis

Early and non‐invasive evaluation of hydatid infestation of brain and spine is of paramount importance, especially in endemic areas. We present a spectrum of imaging findings in neurohydatidosis with a brief review of literature.     

Unbinding process of adsorbed proteins under external stress studied by atomic force microscopy spectroscopy

We report the study of the dynamics of the unbinding process under a force load f of adsorbed proteins (fibrinogen) on a solid surface (hydrophilic silica) by means of atomic force microscopy spectroscopy. By varying the loading rate r(f), defined by f = r(f) t, t being the time, we find that, as for specific interactions, the mean rupture force increases with r(f). This unbinding process is analyzed in the framework of the widely used Bell model. The typical dissociation rate at zero force entering in the model lies between 0. 02 and 0.6 s(-1). Each measured rupture is characterized by a force f(0), which appears to be quantized in integer multiples of 180-200 pN.     

Risk of pulmonary tuberculosis in children with congenital heart disease

Children with low-flow congenital heart lesions are reported to have an increased incidence of pulmonary tuberculosis. The aim of this study was to investigate if children with congenital heart disease have an increased incidence of pulmonary tuberculosis and to determine if patients with certain heart conditions are more susceptible to pulmonary tuberculosis than others. This retrospective study over a 6-year period showed that pulmonary tuberculosis was 2.5-fold more common in children with congenital heart disease than in normal children from the same community. Children with congenital pulmonary stenosis had a prevalence equal to those with acyanotic (ventricular and atrial septal defects) and cyanotic (transposition of the great arteries) high-flow heart lesions, whereas there were no cases of tuberculosis in children with low-flow cyanotic heart lesions such as tetralogy of Fallot. Cardiac surgery had to be postponed as a result of pulmonary tuberculosis in 7.2% of all patients in whom it was required. Over the 6-year period of the study, cardiac surgery had to be delayed in 60% of cases with pulmonary tuberculosis and congenital heart lesions so antituberculosis therapy could be completed. Physicians treating children with congenital heart lesions should maintain a high index of suspicion for the development of pulmonary tuberculosis, especially in those with acyanotic and cyanotic high-flow lesions and pulmonary stenosis.