Poor oral hygiene, oral microorganisms and aspiration pneumonia risk in older people in residential aged care: a systematic review

Background: aspiration pneumonia increases hospitalisation and mortality of older people in residential aged care.Objectives: determine potentially pathogenic microorganisms in oral specimens of older people with aspiration pneumonia and the effect of professional oral care in reducing aspiration pneumonia risk.Data sources: PUBMED/MEDLINE, CINAHL, EMBASE, COCHRANE, PROQUEST, Google Scholar, Web of Science.Study eligibility criteria: published between January 2001 and December 2019 addressing oral microorganisms, aspiration pneumonia, oral health and treatment.Participants: people 60 years and older in residential aged care.Study appraisal and synthesis methods: the Newcastle-Ottawa Scale and the Standard Protocol Items: Recommendations for Intervention Trials checklist.Results: twelve studies (four cross-sectional, five cohort and three intervention) reported colonisation of the oral cavity of older people by microorganisms commonly associated with respiratory infections. Aspiration pneumonia occurred less in people who received professional oral care compared with no such care. Isolation of Candida albicans, Staphylococcus aureus, methicillin-resistant S. aureus and Pseudomonas aeruginosa was related to mortality due to aspiration pneumonia. An interesting finding was isolation of Escherichia coli, a gut bacterium.Limitations: more information may be present in publications about other co-morbidities that did not meet inclusion criteria. A high degree of heterogeneity prevented a meta-analysis. Issues included sampling size, no power and effect size calculations; different oral health assessments; how oral specimens were analysed and how aspiration pneumonia was diagnosed.Conclusions and implications of key findings: pathogenic microorganisms colonising the oral microbiome are associated with aspiration pneumonia in older people in residential care; professional oral hygiene care is useful in reducing aspiration pneumonia risk