111Indium labeling of microorganisms to facilitate the investigation of bacterial adhesion

✍ Scribed by Ardehali, R. ;Mohammad, S. F.

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 684 KB
• Volume: 27
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.820270217

✦ Synopsis

The ability of bacteria to adhere to polymeric interfaces has attracted considerable attention in recent years. Metabolic labeling of microorganisms with 35S- methionine or other p-emitters is commonly utilized for quantification of bacterial adhesion to biopolymers. Since the use of these isotopes is cumbersome, the possibility of labeling the microorganisms with"'Indium, a strong y-emitter, was explored. This report demonstrates that bacteria can be easily labeled with l"1ndium. Stapkylococcus aureus, Stapkylococcus epidermiids, and Pseudomonas aerugznosa were labeled with either lllIndium-oxine or 35S-methionine; and labeling efficiency, retention of incorporated labels, and growth kinetics of labeled bacteria were compared under identical experimental conditions. Bacteria labeled with "'In-oxine incorporated approximately 90% of radioactivity within 10 min, whereas 35S-methionine incorporation required many hours of incubation. Both the incorporated isotopes were gradually released by rapidly growing bacteria into the suspension medium. Of the total incorporated labels, approximately 20% "'In and 15% 35S were released in the surrounding medium every 24 h. No release of incorporated labels occurred when cells were fixed with 2.5% buffered glutaraldehyde. Growth kinetics and scanning or transmission electron microscopic analysis showed no detectable differences among control (nonlabeled), lllIn-, or 35S-labeled bacteria. Labeling of bacteria with "'In-oxine does not interfere with bacterial adherence. These observations suggest that "'In incorporation provides a simple and rapid method of labeling of microorganisms. Compared to currently available techniques, the use of "'In-labeled bacteria will facilitate the quantitation of adherent bacteria to interfaces.