The combination of high bacterial count and positive biofilm formation is associated with the inflammation of pressure ulcers

Mao Kunimitsu,1 Gojiro Nakagami,1,2 Aya Kitamura,1 Yuko Mugita,1 Kaname Akamata,3 Sanae Sasaki,4 Chieko Hayashi,4 Yukie Mori,1 Hiromi Sanada1,2 1Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 2Global Nursing Research Center, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 3Department of Dermatology, The University of Tokyo Hospital, Tokyo, Japan; 4Department of Nursing, The University of Tokyo Hospital, Tokyo, Japan Objective: Evaluating the bacterial bioburden of pressure ulcers through bacterial count and pathogenicity is important but is currently difficult to perform in the clinical setting. In order to address this problem, we proposed two methods: 1) measurement of bacterial count using a quantitative device and 2) detection of biofilm formation by wound blotting. The purpose of this study was to investigate the relationship between the bacterial bioburden, assessed by combining these two methods, and the presence of wound inflammation.Patients and methods: The participants of this cross-sectional study were patients aged >20years with category II, III, IV, or unstageable pressure ulcers examined during a routine round in an interdisciplinary pressure ulcer team between July 2014 and April 2018. Relevant clinical information, including bacterial count, biofilm formation, and presence of inflammation, was collected from the pressure ulcer round record. The relationship between the bacterial bioburden and the presence of inflammation was analyzed using multilevel logistic regression analysis.Results: We included 273 samples obtained from 98 patients. High bacterial count was significantly associated with wound inflammation (P=0.009) and positive biofilm formation tended to be associated with wound inflammation (P=0.076). In terms of combining these parameters, high bacterial count and positive biofilm formation were significantly associated with wound inflammation (OR: 4.61, 95% CI: 1.37–15.46, P=0.013).Conclusion: Assessment using both bacterial count and biofilm detection parameters may provide more accurate evaluation of the bacterial bioburden of the wound and contribute to appropriate wound care. Keywords: wound infection, wound assessment, critical colonization, wound blotting, thermograph