Microtiter enzyme-linked immunosorbent assay using recombinant derived antigens versus western blot in the confirmation of presence of antibodies against the human immunodeficiency virus type 1.

A microtiter enzyme-linked immunosorbent assay using recombinant derived antigens was compared with the Western blot (Dupont) in the confirmation of the presence of antibodies against the human immunodeficiency virus type 1 (HIV-1). Of 104 sera (104 individuals) that were negative by a screening ELISA, 91 were also negative by both confirmation assays. In three sera only the microtiter assay was found to be indeterminate, and in nine other sera only Western blot. The only microtiter assay positive serum was from a male patient at risk for infection with HIV. 279 sera from 83 patients were found positive by screening. Of these, 223 sera were positive in both confirmation assays, and no serum was negative. Only one serum was indeterminate by the microtiter ELISA in contrast to 55 sera, including follow-up samples from 25 patients, most of whom had AIDS, by Western blot (Dupont criteria). However, the number of Western blot indeterminate sera decreased substantially applying less stringent criteria for interpretation. In conclusion, the microtiter ELISA performed well as a confirmation test for the presence of antibodies against HIV-1. In addition, the results demonstrate that in the microtiter assay the envelope peptide kp41 is highly discriminative in detecting anti-HIV-1 negative and anti-HIV-1 positive sera.

A nosocomial outbreak of amoxycillin-resistant non-typable Haemophilus influenzae in a respiratory ward.

A nosocomial outbreak of acute bronchitis due to amoxycillin-resistant, non-typable Haemophilus influenzae occurred in a 23-bed unit, housing patients with respiratory disorders. Within a period of one month, 13 patients and two, previously healthy, members of staff were affected. The isolates were studied for strain relatedness by serotyping, biotyping and major outer membrane protein (MOMP) profiles after SDS-polyacrylamide gel electrophoresis; 13 of the isolates belonged to the same biotype and MOMP type, indicating cross-infection. Routine throat cultures of all patients and personnel were undertaken. To stop the epidemic, patients and nurses positive for amoxycillin-resistant H. influenzae were isolated or sent home and, if symptomatic, were treated with co-trimoxazole. We stress the importance of early intervention when amoxycillin-resistant H. influenzae strains occur in a ward.