Dental Plaque May Harbor Pathogens for Hospital-Acquired Pneumonia

Laurie Barclay, MD

November 11, 2004

Nov. 11, 2004 — Dental plaque (DP) may be a reservoir of pathogens for hospital-acquired pneumonia (HAP), according to the results of a prospective study published in the November issue of Chest.

"Poor dental hygiene has been linked to respiratory pathogen colonization in residents of long-term care facilities," write Ali A. El-Solh, MD, MPH, FCCP, from the School of Dental Medicine, University at Buffalo in New York, and colleagues. "The lack of oral hygiene, the decline in activity of daily living, and the presence of polypharmacy-related xerostomia in institutionalized elders disturb the delicate equilibrium between tooth structure and oral fluids, thus providing favorable conditions for the proliferation of these pathogens."

The investigators obtained plaque index scores and quantitative cultures of DPs in 49 critically ill residents of long-term care facilities when they were admitted to the intensive care unit. Fourteen patients who developed HAP had protected bronchial aspiration and lavage (PBAL), and respiratory pathogens recovered from the PBAL fluid were compared genetically to those isolated from DPs by pulsed-field gel electrophoresis.

Aerobic pathogens colonized DPs in 28 subjects (57%). These isolates included Staphylococcus aureus in 45%, enteric gram-negative bacilli in 42%, and Pseudomonas aeruginosa in 13%. In 10 patients, the investigators documented the etiology of HAP. Of the 13 isolates recovered from PBAL fluid, nine respiratory pathogens were a genotypic match to those recovered from the corresponding DPs of eight patients.

"These findings suggest that aerobic respiratory pathogens colonizing DPs may be an important reservoir for HAP in institutionalized elders," the authors write. "Future studies are needed to delineate whether daily oral hygiene in hospitalized elderly would reduce the risk of nosocomial pneumonia in this frail population.... Meanwhile, it is advocated that active programs be instituted by all health-care practitioners to enhance the access of institutionalized elders to dental care services and to improve daily oral hygiene."

The American Lung Association of New York supported this study.

In an accompanying editorial, Gene R. Pesola, MD, MPH, from Harlem Hospital/Columbia University in New York City, notes that HAP is the leading cause of death from nosocomial infections, with an approximate mortality rate of 16% in the elderly population. He suggests that the findings of this study "have added another piece to the pathophysiologic puzzle of how pneumonia develops by demonstrating that [HAP] can originate from organisms in dental plaque, something that has not been demonstrated before."

Dr. Pesola writes, "Hopefully, with more gains in understanding this complex process of colonization and aspiration of respiratory pathogens, we can interrupt the cycle and reduce the incidence of pneumonia and [HAP]. That time is not yet here."

Chest. 2004;126:1401-1403, 1575-1582

Reviewed by Gary D. Vogin, MD