Assessment of contamination using an ATP bioluminescence assay on doorknobs in a university-affiliated hospital in Japan.
BACKGROUND
Doorknobs are inevitable points of hand contact. We monitored doorknob contamination in a university hospital using an ATP bioluminescence assay and stamp agar method. We selected grip-, lever-, push-, insert-, and two-pull-type doorknobs in staff lavatories and break rooms, a linen closet, dirty utility rooms, a newborn care unit, clinical lavatories and examination rooms, dressing rooms for radiological tests, and lavatories for health examination, as monitoring points in wards and clinics. Sequential monitoring with an ATP assay (six times) and culture (once) were performed at the same time of day in autumn, winter, and summer. We provided contamination data to appropriate healthcare providers and housekeepers, and queried the staff regarding decontamination of doorknobs.


RESULTS
When comparing ATP values on the same type of doorknobs, significant differences in contamination were demonstrated among several clinical rooms and several rooms in wards during all three seasons. No correlation was observed between ATP values on clinical-examination-room doorknobs and outpatient numbers, or between ATP values at any monitoring point and microbial colony-forming units. ATP values on clinical-examination-room doorknobs were reduced after cleaning according to instructions.


CONCLUSIONS
ATP assay is useful for measuring baseline doorknob contamination in clinical rooms. Our findings confirm the need to improve routine decontamination in clinical departments. We need to analyze further the relationship between hospital-acquired infections and doorknob contamination, as assessed by ATP assay in clinics.
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. kajigaya@insti.kitasato-u.ac.jp.
Naoko
N
Kajigaya
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. hirose-y@insti.kitasato-u.ac.jp.|Department of Clinical Laboratory, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. hirose-y@insti.kitasato-u.ac.jp.
Yoneji
Y
Hirose
Department of Clinical Laboratory, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. shink170030@gmail.com.
Shinta
S
Koike
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. atijuf@insti.kitasato-u.ac.jp.|Department of Clinical Laboratory, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. atijuf@insti.kitasato-u.ac.jp.
Tomohiro
T
Fujita
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. yokota-n@insti.kitasato-u.ac.jp.
Norio
N
Yokota
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. hata-s@insti.kitasato-u.ac.jp.
Satsuki
S
Hata
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. ikenato@insti.kitasato-u.ac.jp.
Makoto
M
Ikenaga
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. kenchu@insti.kitasato-u.ac.jp.
Noritada
N
Kobayashi
Department of Infection Control and Prevention, Kitasato University Medical Center, 6-100 Arai, Kitamoto, Saitama, 364-8501, Japan. taka2si@lisci.kitasato-u.ac.jp.|Laboratory of Infectious Diseases, Graduate School of Infection Control Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan. taka2si@lisci.kitasato-u.ac.jp.
Takashi
T
Takahashi
D000255:Adenosine Triphosphate / Q000737:chemistry; D015169:Colony Count, Microbial; D004866:Equipment Contamination / Q000517:prevention & control / Q000706:statistics & numerical data*; D006785:Hospitals, University; D006797:Housekeeping, Hospital / Q000458:organization & administration; D006801:Humans; D007564:Japan; D008163:Luminescent Measurements; D059013:Microbial Consortia / Q000235:genetics; D010362:Patients' Rooms
D000255:Adenosine Triphosphate