Detection of pneumococci in blood cultures by latex agglutination.

Latex agglutination by use of the Pneumoslide test on clinical blood cultures detected 22 Streptococcus pneumoniae strains as the etiological agents in 47 streptococcal septic episodes. The other 25 isolates were identified as viridans streptococci or streptococci of groups A, B, D, or G. The test demonstrated 100% sensitivity, 92% specificity, and predictive values for positive and negative reactions of 91 and 92%, respectively. Two false-positive reactions were caused by strains of viridans streptococci. The two strains continued to give positive reactions when colonies from blood agar plates were tested according to the instructions of the manufacturer. This latex agglutination test is an effective tool for the rapid diagnosis of pneumococci in blood cultures.

Dermatophyte isolation media: quantitative appraisal using skin scales infected with Trichophyton mentagrophytes and Trichophyton rubrum.

Various dermatophyte isolation media were quantitatively appraised by colony counts for their ability to support growth when suspensions of trypsin-treated infected-skin scales were used as inocula. Evaluation included guinea pig skin scales infected with a granular Trichophyton mentagrophyton mentagrophytes, and one trial was conducted using human skin scales infected with Trichophyton rubrum. No differences in the ability to support growth were observed among Taplin Dermatophyte Test medium, Dermatophyte Test Medium (Schering Diagnostics, Port Reading, N.J.),Sabouraud medium plus cycloheximide and chloramphenicol, Youssef medium for dermatophytes product no. 103S semisynthetic lots no. 106 and no. 107. With skin scales not grossly contaminated with bacteria, similar counts were obtained with Littman oxgall agar without antibiotics. Youssef medium for dermatophytes product no. 103N natural lot no. 109 was significantly different from the other media in that lower counts were obtained.