Use this URL to cite or link to this record in EThOS:
Title: Factors Influencing the survival of pathogenic microbes in the built (i.e. hospitals) and natural environments
Author: Alaeq, Rana Abdulrahim
ISNI:       0000 0004 7225 8342
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2018
Availability of Full Text:
Access from EThOS:
Access from Institution:
Healthcare associated infections, i.e. nosocomial infections, occur in patients under medical care. These infections occur during stays in hospital and cause prolonged hospitalisation, disability, and an economic burden. Nosocomial pathogens include bacteria, viruses and fungal parasites. Pathogens living in the healthcare environment and equipment can be an obvious source of pathogen transmission. These pathogens can be transmitted by person to person contact or via contaminated water and food, infected individuals, contaminated healthcare personnel's skin or contact via shared items and surfaces. Pathogens can survive in the hospital environment for long periods and, in some cases, resist disinfection. Bacteria are the most common pathogens responsible for nosocomial infections. The Thesis begins with a description of the aims of the work, followed by studies the distribution of bacteria in the environment and their survival in the healthcare settings, the determination of the number of bacteria on hands after washing and drying normally and following the use of a warm air dryer. The factors which influence the survival of bacteria and Candida in the built environment were also determined on ceramic tiles, copper and plastic plumbing surfaces, and on new toothbrushes. Pathogenic bacteria were isolated from used toothbrushes and the effect of toothpastes on the growth of pathogenic bacteria was determined, as was the effectiveness of antibacterial cloths in inhibiting the growth of bacteria and yeast. The metabolic diversity of the bacterial isolates was also determined. Bacteria were isolated from a range of surfaces commonly found in hospitals and health care settings. A wide variety of bacteria were isolated from sinks, computer keyboards and computer mice, taps and the surface of mobile phones and toilet mirrors. Species of Bacillus were exclusively isolated from vacuum cleaner dust and from books and dust obtained from a library. Bacteria other than just Bacillus were isolated from the soles of shoes. Lift buttons were found to be contaminated with bacteria, not surprisingly with species which are typically skin commensals, with the number being highest on the ground floor-call button. Bacteria were found to be spread by hot-air hand dryers, both into the toilet environment and onto previously washed hands. It is provisionally recommended that disposable paper towels are used in preference to such machines. Bacteria and the yeast, Candida rugosa survived when inoculated onto both rough and smooth tile surfaces similar to those used in health care settings. A wide range of potentially pathogenic bacteria were isolated from used toothbrushes and the survival of inoculated bacteria on tooth brushes was determined. The bacteria were shown to survive for varying periods, a finding of some concern in relation to dental hygiene. A range of toothpastes were also shown to be antibacterial. The survival of inoculated bacteria on copper and plastic surfaces typically used as piping in health care settings was determined. Copper surfaces were shown to be antibacterial, while plastic surfaces were not. It is therefore suggested that in critical healthcare areas, copper piping should be given preference over the plastic variety. Proprietary antibacterial clothes were tested for their antibacterial properties. Despite being marketed for this purpose, the cloths showed no obvious, marked antibacterial activity.
Supervisor: Wainwright, Milton Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available