The effect of cigarette smoke on adherence of respiratory pathogens to buccal epithelial cells

Abstract

Smoking is associated with an increased risk of respiratory tract infection in adults. In children, exposure to cigarette smoke is a risk factor for respiratory tract infection and bacterial meningitis: Active smoking and passive exposure to cigarette smoke is also associated with carriage of some potentially pathogenic species of bacteria in both adults and children. The aims of the study were to determine the effect of active smoking on: (1) bacterial binding to epithelial cells; (2) expression of host cell antigens that act as receptors for some species; and (3) the effects of passive exposure to water-soluble components of cigarette smoke on bacterial binding. Flow cytometry was used to assess binding to buccal epithelial cells of the following species labelled with fluorescein isothiocyanate: Neisseria meningitidis, Neisseria lactamica, Streptococcus pneumoniae, Bordetella pertussis, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus. Flow cytometry was also used to assess expression of host cell antigens which have been identified as bacterial receptors. For each species, binding to cells of smokers was significantly higher than to cells of non-smokers; however, expression of host cell antigens was similar on epithelial cells of both groups. Non-dilute cigarette smoke extract reduced binding of bacteria to epithelial cells, but dilutions between 1 in 10 and 1 in 320 enhanced binding. We conclude that smokers might be more densely colonised by a variety of potentially pathogenic bacteria. The enhanced bacterial binding to epithelial cells of smokers is not related to enhanced expression of host cell antigens that can act as receptors for some species, but possibly to components in the smoke that alter charge or other properties of the epithelial cell surface. Passive coating of mucosal surfaces with components of cigarette smoke might enhance binding of potentially pathogenic bacteria.

Impact of cigarette smoke exposure on host–bacterial pathogen interactions

“…Interestingly, smoking cessation is associated with a reversion to the microflora found in never-smokers, thereby suggesting that cigarette smoke does indeed favour colonisation by pathogens [57]. Supporting this notion, cigarette smoke enhances bacterial attachment to epithelial cells and promotes changes in virulence by modifying bacterial gene expression [58][59][60].…”

Adherence of Type 1-Fimbriated Escherichia coli to Uroepithelial Cells

“…In general, it was found that microorganisms adhere more to (buccal) epithelial cells isolated from patients who either have a chronic disease or smoke (6,19) and to infected human epithelial (HEp-2) cell lines (20) than to cells from healthy control subjects or noninfected cell lines. The same increase has been described in studies on vaginal, buccal, uroepithelial, and periurethral cells isolated from patients (children, girls, and women) with recurrent UTIs (5,21,22).…”

“…Relationships between diseases and the adherence of microorganisms to patient cells have been investigated before (6,19,20). In general, it was found that microorganisms adhere more to (buccal) epithelial cells isolated from patients who either have a chronic disease or smoke (6,19) and to infected human epithelial (HEp-2) cell lines (20) than to cells from healthy control subjects or noninfected cell lines.…”

Smoking and Smokeless Tobacco-Associated Human Buccal Cell Mutations and Their Association with Oral Cancer—A Review

“…For all studies, the adherence of bacteria to buccal cells (see Fig. 1D) was established with the use of a conventional white-light microscope (37,42,50).…”