Incidence of Infection of Enterovirus 71 and Coxsackieviruses A6 and A16 among Household Contacts of Index Cases in Dong Thap Province, Southern Vietnam.

BACKGROUND: Scarce information exists about immunity to hand, foot, and mouth disease (HFMD) among household contacts of index cases in Vietnam and what that means for reducing ongoing HFMD transmission in the community. METHODS: We analyzed neutralizing antibodies (NT) and the incidence of enterovirus (EVs) infection among household contacts of index cases in a province where HFMD remains endemic. Throat swab and 2 mL blood samples from household contacts were collected at enrollment, during and after 2 weeks follow-up. RESULTS: The incidence of EV-A71 infection among household contacts was 40/84 (47.6%, 95% Cl: 36.9-58.3%), compared with 106/336 (31.5%, 95% Cl: 26.6-36.5%) for CV-A6 and 36/107 (33.6%, 95% Cl: 24.7-42.6%) for CV-A16. The incidence of CV-A6 infection was fairly constant across ages; in contrast, CV-A71 and CV-A16 had some variation across ages. At baseline, higher geometric mean titer (GMT) of EV-A71, CV-A6, and CV-A16 antibody titers was found for 25-34-year groups (range 216.3 to 305.0) compared to the other age groups. There was a statistically significant difference in GMT values of CV-A6 and CV-A16 between those who had an infection or did not have infection among households with an index case of these serotypes. CONCLUSIONS: Our results indicated that adults were becoming infected with HFMD and could be contributing to the transmission. There is, therefore, a need for considering the household setting as an additional target for intervention programs for HFMD.

First report on clinical features of Mycoplasma pneumoniae infections in Vietnamese children.

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP) in children, but there has been no clinical report on M. pneumoniae infections in Vietnamese children. We investigated the clinical features of M. pneumoniae infection when the pathogen was detected in the respiratory tract in hospitalized children aged 1-15 years due to lower respiratory tract infections or CAP in Vietnamese children. Throat swabs from 47 patients (18.6%) of 252 patients with a clinical diagnosis of CAP were PCR positive (male, 34; female, 13), and 21 throat swabs (8.3%) showed culture positive for M. pneumoniae. The M. pneumoniae pathogen could be detected by PCR and/or culture in 52 patients (male, 36; female, 16). The major clinical signs in the 52 patients were fever (>38 degrees C) in 100%, pharyngitis in 100%, tachypnea in 94%, dry cough in 86.5%, and rough breathing in 83% of patients. The average term of illness prior to hospitalization was 7.5+/-4.1 days, and the average number of hospitalized days was 7.9+/-3.5 days. Beta-lactam group antibiotics, which were ineffective against M. pneumoniae infection, were used in 37 cases (71%).

Genetic and phenotypic characterization of Haemophilus influenzae type b isolated from children with meningitis and their family members in Vietnam.

To investigate Haemophilus influenzae type b (Hib) infection in Vietnamese children under the age of 5 years, cerebrospinal fluid (CSF) samples from patients with meningitis were screened for Hib, and isolates were subjected to evaluation of susceptibility to 12 antibiotics, biotyping, and genotyping with pulsed-field gel electrophoresis (PFGE). The major biotype was type II (68.3%), followed by type I (22.8%). Among 79 Hib isolates, 45 (57%) were beta-lactamase-producing and ampicillin-resistant (44 and 1 isolates produced TEM-1- and ROB-1-type beta-lactamases, respectively), and 34 isolates (43%) were beta-lactamase-nonproducing and ampicillin-sensitive. No beta-lactamase-nonproducing and ampicillin-resistant isolates were found. The PFGE patterns of Hib isolates were highly divergent, but most could be classified into three clusters. We also investigated Hib colonization in household contacts of patients, and found that Hib isolates from the CSF of patients and from nasopharyngeal cavities of household contacts showed the same PFGE patterns. This observation suggested that household contacts of patients are a possible reservoir of Hib.

Novel erythromycin derivatives with aryl groups tethered to the C-6 position are potent protein synthesis inhibitors and active against multidrug-resistant respiratory pathogens.

A novel series of erythromycin derivatives has been discovered with potent activity against key respiratory pathogens, including those resistant to erythromycin. These compounds are characterized by having an aryl group tethered to the C-6 position of the erythronolide skeleton. Extensive structural modification of the C-6 moiety led to the discovery of several promising compounds with potent activity against both mef- and erm-mediated resistant Streptoccoccus pneumoniae. Preliminary mechanistic studies indicated that the new macrolides are potent protein synthesis inhibitors, which interact with methylated ribosomes isolated from resistant organisms. In experimental animal models, these compounds exhibited excellent in vivo efficacy and balanced pharmacokinetic profiles.

Synthesis of 2-fluoro-6-O-propargyl-11,12-carbamate ketolides. A novel class of antibiotics.

A novel class of 2-fluoro-6-O-propargyl-11,12-carbamate ketolide derivatives of erythromycin has been synthesized for antibacterial SAR studies. Replacement of the C2-hydrogen by a fluorine atom allows the synthesis of 6-O-propargylic ketones and electron-deficient 6-O-propargylic aromatic derivatives by preventing intramolecular C2-enolate Michael cyclization.

Chemotactic factors and renal inflammation.

The mechanisms of leukocyte entry into the kidney during inflammatory renal disease have recently received considerable attention. Chemotactic factors appear to play a central role in this process, not only by inducing leukocyte movement but also by enhancing endothelial and leukocyte adhesiveness and endothelial permeability. The evidence supporting the role of chemotactic factors in renal inflammation comes from three types of studies. (1) Cell culture studies have shown that renal parenchymal cells produce chemotactic factors in response to proinflammatory stimuli. (2) Immunohistochemical and in situ hybridization analyses of renal tissue from patients or experimental animals have demonstrated local renal expression of chemotactic factors in association with inflammatory disease. (3) Experiments designed to neutralize the chemoattractant activity of specific chemotactic factors in leukocyte-dependent models of renal injury have shown an attenuation of inflammatory infiltrates and a decrease in indices of renal damage. In this article, these data are reviewed for complement-derived chemotactic factors, the leukocyte-specific chemokines, and the interstitial chemoattractant osteopontin, and the possibilities of therapeutic interventions based on abrogating chemoattractant expression or function in human renal disease are considered.

Seismic strengthening of reinforced concrete frame buildings

Most reinforced concrete (RC) frame structures in the mid-western and eastern regions of the UNited States are built mainly for gravity loads without proper seismic desgn, and thus are vulnerable to severe damage in the event of a major earthquake in these regions (AU)