In an attempt to identify risk factors for Staphylococcus aureus septicemia, 136 consecutive HIV-infected patients were investigated for the presence of nasopharyngeal colonization with Staphylococcus aureus and subsequent Staphylococcus aureus infection. Sixty of 136 (44.1%) HIV-infected patients had staphylococci which were detected in the nasopharynx on initial culture compared to 12 of 39 (30.8%) patients with chronic diseases and 11 of 47 (23.4%) healthy hospital staff. Another 12 HIV-infected subjects proved to be Staphylococcus aureus carriers on follow-up cultures. Patients with full-blown AIDS had a higher carriage rate compared to subjects who were only HIV-positive (p < 0.05), indicating that Staphylococcus aureus colonized patients were more severely ill. Eight patients with Staphylococcus aureus septicemia were observed, all of whom were carriers; no septicemia occurred in the non-colonized patients (p < 0.01). Colonized patients with neutropenia (< 1000/microliters) were significantly more likely to develop septicemia (p < 0.01). Nasopharyngeal colonization with Staphylococcus aureus and the presence of an indwelling catheter were established to be factors that help identify patients at risk of acquiring subsequent Staphylococcus aureus infection.

The protein B of group B streptococci can bind in a nonimmune reaction to Ig of the IgG and IgM classes of various mammalian species (i.e., human, mouse, rabbit, and bovine). Protein B binding involves the Fc parts of both IgG and IgM molecules. Monoclonal or polyclonal IgG or IgM and the IgM-FC5 mu fragment of human myeloma protein combined with the protein B thereby inhibiting protein B-induced hemolysis in the CAMP reaction. The protein B/Ig complex can be dissociated with 1% Triton or guanidine-HCl (6 M). Mice infected intraperitoneally with sublethal doses of group B streptococci (GBS) and that received seven repeated intravenous injections of highly purified protein B during the first 9 h of infection developed fatal septicemia within 24 h with colony counts of up to 10(8) CFU/ml in the blood. Animals treated in the same way with either PBS or trypsinized protein B recovered. The protein B itself was not pathogenic when injected into healthy mice. Tissue sections of liver or spleen from mice infected with a lethal dose of GBS revealed the presence of protein B together with large numbers of cocci when stained by the peroxidase method using specific antibodies raised against purified protein B in the rabbit.

During a 3-year period the frequency of legionellosis in hospitalized patients with community-acquired and nosocomial pneumonias was 3.4% (23/684 cases) and 5.9% (33/559), respectively. Of the diagnostic tests evaluated, detection of Legionella pneumophila serogroup 1 antigen in urine had the highest sensitivity, with 86% of culture-proven cases being positive. Sensitivities of serologic tests and examination of respiratory secretions (culture and direct immunofluorescence) were 36% and 26%, respectively. The diagnostic value of serology and of examination of respiratory secretions can be low when specimens are obtained and processed under the typical conditions of hospitalization. Urinary antigen detection represents an important diagnostic addition, and examination of postmortem lung tissue from fatal cases with pneumonia is an important adjunct for estimating the prevalence of legionellosis and for assessing the effectiveness of premortem diagnostic tests.

The incidence of community-acquired pneumonia due to Chlamydia pneumoniae was evaluated in a 1-year prospective study of 236 hospitalized patients with 237 manifestations of pneumonia. The microbiological diagnosis was based on results of cultures of blood and sputum or bronchoalveolar lavage fluid and results of complement fixation tests and indirect immunofluorescence of acute- and convalescent-phase sera for C. pneumoniae, Mycoplasma pneumoniae, Legionella species, Coxiella burnetii, and respiratory viruses. Diagnosis of acute C. pneumoniae infection was made on the basis of the results of microimmunofluorescence of paired serum samples. A microbiological diagnosis was obtained in 160 cases (67.5%). C. pneumoniae was the causative agent in 27 patients (11.4%). The following organisms were the other etiologic agents of pneumonia: Streptococcus pneumoniae, 30 cases (12.7%) (bacteremia occurred in 53.3%); Mycoplasma pneumoniae, 22 (9.3%); respiratory viruses, 22 (9.3%); and Enterobacteriaceae, 18 (7.6%). The prevalence of C. pneumoniae antibody in our study population was 47.5%. As has been increasingly reported in recent years and confirmed by this study, C. pneumoniae appears to be a common etiologic agent of community-acquired pneumonia and upper respiratory tract infection in Germany.

OBJECTIVES: To undertake a multicenter study to evaluate the Biotest legionella urinary antigen enzyme immunoassay (EIA) performance against those EIAs already in use in 14 European laboratories. METHODS: Each laboratory examined urine specimens from appropriate patients using both their current assay and the Biotest EIA. Each examined: a standard panel of 12 coded urine samples (distributed by Biotest); a panel of 10 coded urine samples provided as part of a European external quality assurance (EQA) scheme; urine samples from patients with proven legionnaires' disease (LD); urine samples from patients with pneumonia of microbiologically proven cause other than LD; and urine samples submitted for routine examination. Thus, the performance of the Biotest assay (in comparison with current EIAs), its specificity and utility, and the inter-laboratory agreement were assessed. RESULTS: Inter-laboratory agreement was excellent, with all participants obtaining the expected results for 20 of 22 coded urine specimens. Specificity, determined using 123 specimens from patients with infections of known etiology, was 100%. The Biotest EIA gave positive results in 86% of specimens which had been positive in the laboratories' current EIAs, and in 94.6% of those specimens which were positive for Legionella pneumophila serogroup 1. CONCLUSION: The Biotest EIA is simple to use and specific and the results obtained in different laboratories show excellent agreement. The assay compares well existing EIAs, at least for L. pneumophila serogroup 1