Genetic diversity of human rhinoviruses in Cambodia during a three-year period reveals novel genetic types.

Acute respiratory viral infections are a major cause of morbidity during early childhood in developing countries. Human rhinoviruses are the most frequent cause of upper respiratory tract infections in humans, which can range in severity from asymptomatic to clinically severe disease. In this study we collected 4170 nasopharyngeal swabs from patients hospitalised with influenza-like illness in two Cambodian provincial hospitals between 2007 and 2010. Samples were screened for 18 respiratory viruses using 5 multiplex PCRs. A total of 11.2% of samples tested positive for human rhinoviruses (HRV). VP4/2 and VP1 regions were amplified and sequenced to study the distribution of rhinoviruses genotypes and species in Cambodia during this three-year period. Five novel genotypes, 2 species A, 2 species B and 1 species C were identified based on VP1 sequences. Co-infections with other viruses were demonstrated.

Respiratory virus infections in hospitalized children and adults in Lao PDR.

BACKGROUND: Acute respiratory infections are an important cause of morbidity and mortality worldwide, with a major burden of disease in developing countries. The relative contribution of viruses in acute lower respiratory infections (ALRI) is, however, poorly documented in Lao PDR. OBJECTIVE: The objective of this study is to investigate the etiology of ALRI in patients of all ages in two hospitals of Laos. METHODS: Multiplex PCR/RT-PCR methods were used to target 18 major common respiratory viruses. Between August 2009 and October 2010, samples from 292 patients presenting with ALRI were collected. RESULTS AND CONCLUSION: Viruses were detected in 162 (55%) samples. In 48% (140/292) of the total ALRI cases, a single virus was detected while coinfections were observed in 8% (22/292) of the samples. The most frequent viruses were rhinovirus/enterovirus (35%), human respiratory syncytial virus (26%), and influenza viruses (13%). Parainfluenza viruses were detected in 9%, adenovirus in 6%, human metapneumovirus in 4%, coronaviruses (229E, NL63, OC43, HKU1) in 4%, and bocavirus in 3% of ALRI specimens. Most viral infections occurred in patients below 5 years of age. The distribution of viruses varied according to age-groups. No significant correlation was observed between the severity of the disease and the age of patients or the virus species. This study provides the description of viral etiology among patients presenting with ALRI in Lao PDR. Additional investigations are required to better understand the clinical role of the different viruses and their seasonality in Laos.

Synthesis of mosaic peptidoglycan cross-bridges by hybrid peptidoglycan assembly pathways in gram-positive bacteria.

The peptidoglycan cross-bridges of Staphylococcus aureus, Enterococcus faecalis, and Enterococcus faecium consist of the sequences Gly(5), l-Ala(2), and d-Asx, respectively. Expression of the fmhB, femA, and femB genes of S. aureus in E. faecalis led to the production of peptidoglycan precursors substituted by mosaic side chains that were efficiently used by the penicillin-binding proteins for cross-bridge formation. The Fem transferases were specific for incorporation of glycyl residues at defined positions of the side chains in the absence of any additional S. aureus factors such as tRNAs used for amino acid activation. The PBPs of E. faecalis displayed a broad substrate specificity because mosaic side chains containing from 1 to 5 residues and Gly instead of l-Ala at the N-terminal position were used for peptidoglycan cross-linking. Low affinity PBP2a of S. aureus conferred beta-lactam resistance in E. faecalis and E. faecium, thereby indicating that there was no barrier to heterospecific expression of resistance caused by variations in the structure of peptidoglycan precursors. Thus, conservation of the structure of the peptidoglycan cross-bridges in members of the same species reflects the high specificity of the enzymes for side chain synthesis, although this is not essential for the activity of the PBPs.