Characteristics of aerobic gram-negative bacteria colonizing critically ill patients.
Adherence of gram-negative bacteria (GNB) to epithelial surfaces is important for GNB colonization to occur. Pili, rodlike structures projecting from the outer membrane of GNB, and GNB surface hydrophobicity have been shown to enhance GNB adherence. We investigated the types of pili and the hydrophobicity of aerobic GNB colonizing the stomach, oropharynx, and trachea of critically ill patients. Piliation and hydrophobicity of oral, tracheal, and gastric GNB were compared with that of commensal GNB isolated from patients' rectums. Significantly more oropharyngeal than rectal GNB were piliated, and the most common type of pili present was type 1, or mannose-sensitive pili. Mannose-resistant and P pili were present less often, and no colonizing GNB had S pili. Colonizing GNB were hydrophilic rather than hydrophobic, and no differences in hydrophobicity were noted between colonizing GNB and rectal isolates. Our results suggest that pili may be important for oropharyngeal GNB colonization.
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9034.
S G
SG
Donaldson
S Q
SQ
Azizi
A R
AR
Dal Nogare
D001422:Bacterial Adhesion; D001424:Bacterial Infections / Q000382:microbiology; D003422:Critical Care; D003428:Cross Infection / Q000382:microbiology; D010861:Fimbriae, Bacterial / Q000648:ultrastructure; D006088:Gram-Negative Aerobic Bacteria / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D008875:Middle Aged; D009960:Oropharynx / Q000382:microbiology; D011014:Pneumonia / Q000382:microbiology; D011446:Prospective Studies; D012007:Rectum / Q000382:microbiology; D013270:Stomach / Q000382:microbiology; D014132:Trachea / Q000382:microbiology; D014867:Water / Q000378:metabolism
D014867:Water