Comparison of multidimensional scaling and principal component analysis of interspecific variation in bacteria

Multidimensional scaling (MDS) and principal component analysis (PCA) were applied to bacterial taxonomy. The biochemical profiles of 42 isolates consisting of four species of Enterobacteriaceae were used. Both MDS and PCA use proximity measures such as the correlation coefficient or Euclidean distance to generate a spatial configuration (map) of points in multidimensional space where distances between points reflect the similarity among isolates. Multidimensional scaling and principal component analysis were able to discriminate organisms in two dimensions. The test components of the MDS and PCA factors (derived variables composed of linear combination of biochemical tests) were different for a two-dimensional solution.

Postoperative infection caused by an unusual serotype of Streptococcus pneumoniae associated with multiple drug resistance

A 15-month-old child developed an infectious pulmonary complication of open heart surgery. Cultures of the respiratory secretions showed growth of a 9L serotype of Streptococcus pneumoniae which was resistant to penicillin, tetracycline, and chloramphenicol. There was no evidence that the organism was spread among the family of the patient or hospital personnel.

Comparative in vitro activities of N-formimidoyl thienamycin and moxalactam against nonfermentative aerobic gram-negative rods

N-Formimidoyl thienamycin was the most active drug against strains of Pseudomonas aeruginosa with a 90% minimum inhibitory concentration of 1.25 mug/ml. With the exception of P. maltophilia, thienamycin was as active or more active than moxalactam against other species of pseudomonads and against other genera of nonfermenters.