Necrotizing Fasciitis Caused by Group A Streptococcus.

BACKGROUND: Group A Streptococcus causes a variety of human infections, including the life-threatening necrotizing fasciitis, which may be ignored by the patient. From hours to days, the infection may progress from an apparently benign skin lesion, usually mistaken for a spider or insect bite, to a highly lethal disease. We present a case of 57-year-old male with skin lesions on swelling left upper limb. METHODS AND RESULTS: The culture of secretion from epidermis and blood were positive for Group A Streptococcus (GAS), type ß hemolytic streptococcus. Intensive anti-infection therapy was applied. However, the necrosis of the limb deteriorated rapidly. He died from multiple organ failure, streptococcal toxic shock syndrome (STSS) and disseminated intravascular coagulation 13 days later. CONCLUSIONS: Necrotizing fasciitis is a rapidly progressive, destructive bacterial infection. Early recognition is the most important factor for survival.

SHP2 positively regulates TGFß1-induced epithelial-mesenchymal transition modulated by its novel interacting protein Hook1.

The epithelial-mesenchymal transition (EMT) is an essential process for embryogenesis. It also plays a critical role in the initiation of tumor metastasis. Src homology 2 (SH2)-domain containing protein-tyrosine phosphatase-2 (SHP2) is a ubiquitously expressed protein-tyrosine phosphatase and is mutated in many tumors. However, its functional role in tumor metastasis remains largely unknown. We found that TGFß1-induced EMT in lung epithelial A549 cells was partially blocked when SHP2 was decreased by transfected siRNA. The constitutively active form (E76V) promoted EMT while the phosphatase-dead mutation (C459S) and the SHP2 inhibitor PHPS1 blocked EMT, which further demonstrated that the phosphatase activity of SHP2 was required for promoting TGFß1-induced EMT. Using the protein-tyrosine phosphatase domain of SHP2 as bait, we identified a novel SHP2-interacting protein Hook1. Hook1 was down-regulated during EMT in A549 cells. Overexpression of Hook1 inhibited EMT while knockdown of Hook1 promoted EMT. Moreover, both the protein-tyrosine phosphatase domain and N-terminal SH2 domain of SHP2 directly interacted with Hook1. Down-regulation of Hook1 increased SHP2 activity. These results suggested that Hook1 was an endogenous negative regulator of SHP2 phosphatase activity. Our data showed that the protein-tyrosine phosphatase SHP2 was involved in the process of EMT and Hook1 repressed EMT by regulating the activation of SHP2. SHP2-Hook1 complex may play important roles in tumor metastases by regulating EMT in cancer cells.

Clinical laboratory evaluation of COVID-19.

COVID-19, caused by SARS-CoV-2, is a highly infectious disease, and clinical laboratory detection has played important roles in its diagnosis and in evaluating progression of the disease. Nucleic acid amplification testing or gene sequencing can serve as pathogenic evidence of COVID-19 diagnosing for clinically suspected cases, and dynamic monitoring of specific antibodies (IgM, IgA, and IgG) is an effective complement for false-negative detection of SARS-CoV-2 nucleic acid. Antigen tests to identify SARS-CoV-2 are recommended in the first week of infection, which is associated with high viral loads. Additionally, many clinical laboratory indicators are abnormal as the disease evolves. For example, from moderate to severe and critical cases, leukocytes, neutrophils, and the neutrophil-lymphocyte ratio increase; conversely, lymphocytes decrease progressively but are over activated. LDH, AST, ALT, CK, high-sensitivity troponin I, and urea also increase progressively, and increased D-dimer is an indicator of severe disease and an independent risk factor for death. Severe infection leads to aggravation of inflammation. Inflammatory biomarkers and cytokines, such as CRP, SAA, ferritin, IL-6, and TNF-α, increase gradually. High-risk COVID-19 patients with severe disease, such as the elderly and those with underlying diseases (cardiovascular disease, diabetes, chronic respiratory disease, hypertension, obesity, and cancer), should be monitored dynamically, which will be helpful as an early warning of serious diseases.

Human cytomegalovirus glycoprotein B genotype correlates with different symptoms of infected infants.

OBJECTIVES: Human cytomegalovirus (HCMV) is the pathogen of cytomegalic inclusion disease of infants. HCMV strains can be classified into four genotypes of glycoprotein B (gB). There are limited data concerning links between clinical symptoms and HCMV genotypes. The aims of the present study were to determine the genotype of HCMV isolates from pediatric patients who have different symptoms on the assumption that the gB genotype may influence the outcomes of congenital and prenatal HCMV infection. METHODS: The gB types of HCMV were determined in urine specimens from 208 infected infants using nested polymerase chain reaction and restriction fragment length polymorphism. RESULTS: These data showed the dominance of the gB1 genotype in HCMV-infected infants. The distributions of HCMV gB genotypes in jaundice, malformation, and pneumonia patients are different. CONCLUSION: There are some relationships between the gB genotypes and the different symptoms of HCMV infection. The four gB genotypes of HCMV may have different clinical outcomes in infected infants.