Bacterial Adherence to Pharyngeal Cells: In Vitro Studies with Alpha-haemolytic Streptococci and Haemophilus influenzae

Abstract

We examined the adherence to pharyngeal cells of alpha-haemolytic Streptococci (AHS) and Haemophilus influenzae, representing normal flora and otitis media (OM) pathogens, respectively. The bacteria were incubated with epithelial cells brushed from the tonsils, adenoid or tubal orifice of children and adults. Adherence varied among the clinical isolates of AHS and H. influenzae. AHS adhered better to epithelial cells from a child compared with those sampled from an adult. The bacteria adhered better to cells from the tubal orifice compared with those sampled from the adenoid. The selective attachment of AHS to certain cells but not to others could not be correlated to apoptotic/necrotic cells versus viable cells. Incubation of epithelial cells with an isolate of AHS with good inhibitory activity against OM pathogens showed almost no adherence of bacteria to the epithelial cells after 12 and 24 h of incubation. If, however, an isolate of AHS with weak inhibitory activity was incubated with the cells, the bacteria that were attached to the epithelial cells from the beginning showed overgrowth in the broth and increasing attachment to the cells after 12 and 24 h. Thus the inhibitory activity of AHS could also affect the adherence of potential pathogens to the mucosal surfaces. The adherence pattern may at least partially explain the difference in susceptibility to OM between children and adults.

The ecology of nasal colonization of Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus: the role of competition and interactions with host's immune response

“…In fact, it has been proposed that the production of hydrogen peroxide by S. pneumoniae may affect the densities of S. aureus and H. influenzae as both are susceptible to hydrogen peroxide killing [24,25,34,35]. However in this and a previous work that specifically addressed this issue [36] we found no evidence that hydrogen peroxide produced by S. pneumoniae limits the colonizing populations of either of the two species.…”

Viral and Bacterial Interactions in the Upper Respiratory Tract

“…Possible mechanisms by which commensals might prevent disease are inhibition of colonization and expansion of potential pathogens, immune modulation, and stimulation of mucosal maturation and barrier function [5]. Most research on colonization resistance in the nasopharyngeal niche by commensals has been performed on alpha-haemolytic (AHS) and beta-haemolytic (BHS) streptococcal species [18][19][20][21][22]. An overview of the available evidence regarding interactions between pathobionts and between pathobionts and commensal bacteria can be found in Table S1 and Figure S1 in Text S1.…”

Nasopharyngeal microbiota in infants and changes during viral upper respiratory tract infection and acute otitis media

“…Less is known about the colonization of commensals and their dynamics during viral URI. Existing data suggest interference between otopathogens and commensals [13][14][15]. Therefore, enhancement of commensal colonization may interfere with otopathogen colonization leading to disease prevention.…”