Clinical and microbiological features of melioidosis in northern Vietnam.

Sporadic cases of melioidosis have been reported from Vietnam for decades, but clinical and epidemiological data for the indigenous population are still scarce. In this study, we reviewed clinical and demographic data of patients with culture-proven melioidosis diagnosed at a single large referral hospital in Hanoi between November 1997 and December 2005. We found that the clinical manifestations of melioidosis (with fatal septicaemia as the most common presentation), a high rate of underlying diseases, and a peak of cases admitted during the wet season, were similar to studies from other endemic areas. The geographical origin of patients with melioidosis showed that melioidosis existed in at least 18 northern provinces. The characterization of clinical Burkholderia pseudomallei strains by multilocus sequence typing identified 17 different sequence types (STs), 11 of which have (as yet) not been found outside Vietnam. Several of these STs presumably were generated through recent evolutionary events in this rapidly diversifying bacterial species, and thus, restricted geographic distribution may be a consequence of limited time passed since emergence. To our knowledge, this is the first report on a series of cases describing clinical and epidemiological features of melioidosis and corresponding B. pseudomallei strains from northern Vietnam.

Detection of antibodies against adenovirus protein IX, fiber, and hexon in human sera by immunoblot assay.

The 51 serotypes of human adenoviruses (HAdVs) of the genus Mastadenovirus are classified into the six species HAdV-A to HAdV-F. For the detection of genus- and species-specific antibodies in human sera an immunoblot assay was developed. The recombinant long fiber of HAdV-41[F] (Ad41Fi) and the native hexon of HAdV-5[C] were used as genus-specific antigens. The recombinant capsid protein IX (pIX) of HAdV-2 (Ad2pIX[C]) and HAdV-41 (Ad41pIX[F]), the C-terminal pIX part of HAdV-3 (Ad3pIXC[B]), and the fiber knob of HAdV-8 (Ad8FiKn[D]) were evaluated as representative species-specific antigens. Hence, the pIX amino acid sequences of numerous serotypes of all HAdV species were compared, and the cross-reactivities of pIX antigens with rabbit hyperimmune sera among HAdV-A to -F were analyzed. In an epidemiological study, 667 human patient sera, not selected for viral infection, were screened for adenovirus seroprevalence. The genus-specific antibody prevalences directed against the Ad41Fi and HAdV-5 hexon were 82.8 and 98.8%, respectively. The species-specific antibody prevalence of 44.7% against Ad2pIX[C], 36.6% against Ad41pIX[F], 26.4% against Ad8FiKn[D], and 18% against Ad3pIXC[B] showed an age-dependent distribution and correlated well with the frequency of isolated serotypes of the respective species in earlier studies (except HAdV-D). In conclusion, the immunoblot assay using pIX, fiber, and hexon antigens represents a valuable and new serological tool for refined adenovirus diagnosis as shown in an epidemiological study.

Human adenovirus and human cytomegalovirus infections in preterm newborns: no association with bronchopulmonary dysplasia.

Connatal infection with human adenovirus (HAdV) has been recently proposed as a cofactor for the development of bronchopulmonary dysplasia (BPD) in preterm infants [Couroucli et al. 2000 Pediatr Res 47:225-232]. In another study, BPD was associated with an increased incidence of human cytomegalovirus (HCMV) infection [Sawyer et al. 1987 Am J Dis Child 141:303-305]. During a 18-mo study period, we investigated tracheal aspirates or pharyngeal aspirates and urine samples collected during the first month of life from 66 preterm newborns with very low birth weight (< or =1.500 g) for replication-potent HAdV as well as for adenoviral and HCMV DNA by virus culture and qualitative DNA PCR. Thus, our study included not only prenatal but also peri- and postnatal infections. Thirty-seven percent (24/66) of infants developed BPD(1), as defined by persistent oxygen dependency at day 28 of life. Replication-potent HAdV and/or adenoviral DNA could be detected repeatedly in tracheal aspirates/pharyngeal aspirates and/or urine from 20% (13/66) of preterm infants. Seventeen percent (4/24) of infants in the BPD(1) group and 21% (9/42) of infants in the non-BPD group had an HAdV infection, indicating that in our study the very recently proposed association between HAdV infection of the lung and BPD could not be confirmed. For comparison, active HCMV infection was diagnosed in 18% (12/66) of infants, 3 of which developed HCMV disease. 29% (7/24) in the BPD(1) group and 12% (5/42) in the non-BPD group were positive for HCMV. Again, there was no statistically significant association between HCMV infection and BPD. In summary, our findings indicate that HAdV and HCMV infection are frequent in preterm newborns with very low birth weight; however, a causal association with the development of BPD seems unlikely.