Morphological and bio chemical variations of Haemophilus influenzae type Binduced by Ph and temperature changes

Haemophilus influenzae type b ATCC 10211 was cultured at different temperat ures (25 degreesC - 49 degreesC) and pH values (5.7 - 8.7) either in liquid or semisolid medium. Morphological variations of individual cells were not ed by optical microscopy depending upon the conditions of growth. At higher temperatures filaments were produced whereby the length of individual cell s increased compared to cultures grown at 37 degreesC. Filaments were also observed at lower pH values. Culture conditions also af fected colonial morphology. At low pH values colonies had an enhanced lobul ated contour and were more wrinkly and rougher than at higher pH. The chang es in cellular and colonial morphology were correlated with distinct outer membrane protein profiles. The changes in temperature and pH did not affect identification of the microorganism by the API system.