Application of capillary electrophoresis mass spectrometry and liquid chromatography multiple-step tandem electrospray mass spectrometry to profile glycoform expression during Haemophilus influenzae pathogenesis in the chinchilla model of experimental otitis media.
Otitis media caused by nontypeable Haemophilus influenzae (NTHi) is a common and recurrent bacterial infection of childhood. The structural variability and diversity of H. influenzae lipopolysaccharide (LPS) glycoforms are known to play a significant role in the commensal and disease-causing behavior of this pathogen. In this study, we determined LPS glycoform populations from NTHi strain 1003 during the course of experimental otitis media in the chinchilla model of infection by mass spectrometric techniques. Building on an established structural model of the major LPS glycoforms expressed by this NTHi strain in vitro (M. Månsson, W. Hood, J. Li, J. C. Richards, E. R. Moxon, and E. K. Schweda, Eur. J. Biochem. 269:808-818, 2002), minor isomeric glycoform populations were determined by liquid chromatography multiple-step tandem electrospray mass spectrometry (LC-ESI-MS(n)). Using capillary electrophoresis ESI-MS (CE-ESI-MS), we determined glycoform profiles for bacteria from direct middle ear fluid (MEF) samples. The LPS glycan profiles were essentially the same when the MEF samples of 7 of 10 animals were passaged on solid medium (chocolate agar). LC-ESI-MS(n) provided a sensitive method for determining the isomeric distribution of LPS glycoforms in MEF and passaged specimens. To investigate changes in LPS glycoform distribution during the course of infection, MEF samples were analyzed at 2, 5, and 9 days postinfection by CE-ESI-MS following minimal passage on chocolate agar. As previously observed, sialic acid-containing glycoforms were detected during the early stages of infection, but a trend toward more-truncated and less-complex LPS glycoforms that lacked sialic acid was found as disease progressed.
Lundström
Susanna L
SL
Karolinska Institutet and University College of South Stockholm, Clinical Research Center, NOVUM, S-141 86 Huddinge, Sweden.
Li
Jianjun
J
Månsson
Martin
M
Figueira
Marisol
M
Leroy
Magali
M
Goldstein
Richard
R
Hood
Derek W
DW
Moxon
E Richard
ER
Richards
James C
JC
Schweda
Elke K H
EK
D000818:Animals; D002682:Chinchilla; D002853:Chromatography, Liquid / Q000379:methods; D004195:Disease Models, Animal; D019075:Electrophoresis, Capillary / Q000379:methods; D006192:Haemophilus Infections / Q000382:microbiology* / Q000503:physiopathology; D006193:Haemophilus influenzae / Q000378:metabolism / Q000472:pathogenicity*; D006801:Humans; D007536:Isomerism; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism*; D010033:Otitis Media / Q000382:microbiology* / Q000503:physiopathology; D010034:Otitis Media with Effusion / Q000382:microbiology; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
D008070:Lipopolysaccharides