Staphylococcal Cassette Chromosome mec and Panton-Valentine Leukocidin Characterization of Methicillin-Resistant Staphylococcus Aureus Clones

Staphylococcal cassette chromosome mec (SCCmec) types and Panton-Valentine leukocidin (PVL) gene carriage were compared among suspected community-associated methicillin-resistant Staphylococcus aureus MRSA (CA-MRSA) and health care-associated MRSA (HA-MRSA) isolates. CA-MRSA isolates carried the SCCmec type IV complex, and most were PVL positive. The HA-MRSA isolates carried the SCCmec type II complex and did not harbor the PVL genes

Practical guidance for clinical microbiology laboratories: Viruses causing acute respiratory tract infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens

Comparison of DNA Pyrosequencing with Alternative Methods for Identification of Mycobacteria▿

Identification of mycobacterial clinical isolates by pyrosequencing within the hypervariable A region of the 16S rRNA gene was compared to other identification methods. For >90% of isolates, these identifications correlated to the level of complex or species. For identification of many mycobacteria, pyrosequencing offers an inexpensive alternative to traditional sequencing

Chlamydia pneumoniae Infection Induces Differentiation of Monocytes into Macrophages

Migration and differentiation of monocytes to the intima of blood vessels may be a crucial first step in the development of atherosclerosis associated with Chlamydia (Chlamydophila) pneumoniae. However, the involvement of C. pneumoniae infection in such steps is not clear. In the present study, therefore, the differentiation-inducing activity of C. pneumoniae to monocytes was examined. Human THP-1 monocytic cell line cells were infected with C. pneumoniae, and the differentiation of monocytes to macrophages was assessed by cell morphology, phagocytic activity, and expression of a cell surface adhesion molecule. The monocytic cells infected with viable bacteria markedly differentiated into macrophages associated with diffused cell morphology, increased uptake of polystyrene beads and increased ICAM-1 (intercellular adhesion molecule 1) expression on the cell surfaces. Heat-killed bacteria did not induce any morphological changes or increase of phagocytosis, but they did induce an increase of cell surface ICAM-1 expressions in THP-1 monocytic cells. The antibiotic minocycline treatment of infected cells resulted in marked inhibition of the cell differentiation as well as C. pneumoniae growth in the cells, but not ICAM-1 expression. In addition, the experiments with human peripheral blood monocytes infected with C. pneumoniae also showed the differentiation of macrophages assessed by morphological change and phagocytic activity. These results indicate that C. pneumoniae infection may directly induce the differentiation of monocytes to macrophages. However, antigenic stimulation of monocytes with bacteria may not be sufficient for a full macrophage differentiation

Staphylococcal Cassette Chromosome mec and Panton-Valentine Leukocidin Characterization of Methicillin-Resistant Staphylococcus aureus Clones

Staphylococcal cassette chromosome mec (SCCmec) types and Panton-Valentine leukocidin (PVL) gene carriage were compared among suspected community-associated methicillin-resistant Staphylococcus aureus MRSA (CA-MRSA) and health care-associated MRSA (HA-MRSA) isolates. CA-MRSA isolates carried the SCCmec type IV complex, and most were PVL positive. The HA-MRSA isolates carried the SCCmec type II complex and did not harbor the PVL genes

Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens