Persistence of microbes

Persistence of microbes

• 1.
  How long donosocomial pathogens persist on inanimate surfaces? A systematic review Reviewed by Dr. Sayan Chakraborty MD (JR-2), Dept. of Tropical Medicine Calcutta School of Tropical Medicine
• 2.
  Author: Axel Kramer BMCInfectious Diseases BMC series open, inclusive and trusted 2006 6:130 DOI: 10.1186/147123346130 © Kramer et al; licensee BioMed Central Ltd. 2006 Received: 26 April 2006 Accepted: 16 August 2006 Published: 16 August 2006
• 3.
  BACKGROUND • Global infectioncontrol community: ongoing controversy about the appropriate t/t of inanimate surfaces in hospitals • Non-antimicrobial detergents/ antimicrobial agents ?? • Parameters to be noted:  Type of ward  Expected frequency of hand contact with a surface Persistence of nosocomial pathogens on surfaces
• 4.
  METHODS • Search strategy: Reviewedin MedLine on the internet homepage of the National Library of Medicine Standard textbooks on infection control, bacteriology and virology • Selecting studies: Reports with experimental evidence • Interpretation of studies: Pathogens were grouped according to importance and persistence
• 5.
  RESULTS • Persistence ofbacteria
• 6.
  RESULTS- Bacteria
• 7.
  RESULTS - Bacteria •Gram negative persist longer than gram positive • Humid conditions improved persistence • Only Staphylococcus aureus persist longer at low humidity • Low temperatures, e.g., 4°C or 6°C, also improved persistence • Test material -no consistent result. However, longer persistence noted on plastic & steel • Longer persistence with higher inocula, in the presence of protein, serum, sputum or without dust
• 8.
  RESULTS- Fungi The presenceof serum or albumin, low temp & high humidity lead to longer persistence
• 9.
  RESULTS - Virus
• 10.
  RESULTS - Virus
• 11.
  RESULTS - VIRUS •Viruses of Respiratory tract: a few days • Viruses of GI tract: 2 months • Blood borne viruses eg HBV or HIV > 1 week • High humidity: Entero- & Rhinovirus • Low humidity: HSV & HAV • Low temp: Astro-, Adeno-, Polio, HSV & HAV • Type of material inconsistent • Non-porous substance- Influenza; Fomica & gloves- RSV; Telephone receiver- FCV • Longer persistence in fecal suspension & higher inoculum
• 12.
  DISCUSSION • Factors influencinghigher persistence: Low temperature High humidity Higher inoculum Type of surface & suspension medium – inconsistent • Cryptosporidium species survive on dry surfaces for only 2 hours
• 13.
  HAND HYGIENE • Transmissionto hands:  Escherichia coli (100%)  Salmonella spp. (100%)  Staphylococcus aureus (100%)  Candida albicans (90%)  Rhino virus (61%)  HAV (22% – 33%)  Rota virus (16%). • Contaminated hands can transfer viruses to 5 more surfaces or 14 other subjects. • Recontaminating of surface, as in HAV. • Compliance rates of healthcare workers in hand hygiene around 50%
• 14.
  Common modes oftransmission from inanimate surfaces to susceptible patients
• 15.
  DISCUSSION …. contd •During outbreaks, role of environmental contamination stronger for Clostridium difficile, MRSA and VRE than for Pseudomonas aeruginosa or Acinetobacter baumannii • Routine treatment of floors with surface disinfectants - no significant impact • Disinfection of surfaces in the immediate environment of patients reduce nosocomial infection
• 16.
  CONCLUSION • Most nosocomialpathogens persist on inanimate surfaces for weeks or even months • Disinfection of surfaces in specific patient care areas • PROPER HAND HYGIENE
• 17.
  THANK YOU