Measurement of motility of Helicobacter pylori, Campylobacter jejuni, and Escherichia coli by real time computer tracking using the Hobson BacTracker.
OBJECTIVE
(1) To make precise measurements and comparisons of various aspects of motility of three gastrointestinal pathogens, Helicobacter pylori, Campylobacter jejuni, and Escherichia coli, in log phase growth; (2) to provide background information on motility data to study the influence of pH, viscosity, and chemotactic factors, thereby gaining a better understanding of bacterial pathogenesis.


METHODS
Computer image processing technology and phase contrast microscopy (Hobson BacTracker) were used to measure several indices of bacterial motility in real time. Ten clinical isolates of each species in log phase liquid culture were studied.


RESULTS
C jejuni moved fastest, with a median curvilinear velocity (CLV) of 38.76 microns/s (range 29.08 to 52.82). Next was H pylori, median CLV 25.02 microns/s (range 12.07 to 29.07). E coli was the slowest, median CLV 12.73 microns/s (range 8.20 to 18.04). The straight line velocities showed similar trends. Measurement of track linearity (TL) showed that C jejuni moved the straightest (TL 60.3%), H pylori moved in wide circles (TL 28.7%), and E coli showed spinning movement without much linear displacement (TL 18.3%). There were significant differences in these three variables between the species studied, but no significant differences in measurements of time and frequency of halts between movement runs.


CONCLUSIONS
The BacTracker provides a useful technical aid for measuring several indices of bacterial motility objectively, reproducibly, and precisely, which is difficult to achieve without computer assistance. Accurate quantification of motility provides a basis for studying the factors which influence bacterial motility. It can provide phenotypic measurements of the effect of flagellar gene depletion.
Karim
Q N
QN
Department of Microbiology, Imperial College of Science, Technology and Medicine at St Mary's Hospital, London, UK.
Logan
R P
RP
Puels
J
J
Karnholz
A
A
Worku
M L
ML
D018407:Bacterial Physiological Phenomena; D001431:Bacteriological Techniques; D016123:Campylobacter jejuni / Q000502:physiology; D004926:Escherichia coli / Q000502:physiology; D016480:Helicobacter pylori / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D009068:Movement