Disinfection as a part of the Infection control practice in a hospital includes disinfection of the environment & instruments. Disinfectant procedures therefore need to be preceded by appropriate cleaning protocols in order to achieve optimal results. Dr Shalini Naik, Associate Professor, Department of Microbiology, MS Ramaiah Hospital, Bengaluru shares her perspective
Disinfectants are used on inanimate objects and cleaning ensures the removal of organic matter and allows the disinfectant to come into complete surface contact with the article to be disinfected. The chemical disinfectants used generally for patient-care equipment are alcohols, glutaraldehyde, formaldehyde, hydrogen peroxide, iodophors, ortho-phthalaldehyde, peracetic acid, phenolics, quaternary ammonium compounds and chlorine. The choice as to which disinfectant can be used depends upon the article being disinfected and the purpose of use of the article. Some microbes are resistant to a number of commonly used chemicals and hence this should be given consideration while making a choice of the disinfectant.
The constant patient inflow leads to a continuous circulation of micro-organisms in the hospital setting. Operation theatres, intensive care units, emergency rooms, labour rooms are areas where patients are at a higher risk of acquiring infection. These areas are cleaned using separate equipment with detergent/disinfectant solutions more so as the spills of body fluids are disinfected. Though the routine use of germicidal disinfectants for environmental surfaces like the hospital floor is a debatable subject, there are studies which prove that there is not much difference in the rate of healthcare infections after either a detergent or disinfectant cleaning protocol. However, there are many studies which prove beyond doubt that disinfectants are more effective in reducing the microbial load as compared to detergents.
Sources of infection
Hospital administrators do not see Out Patient Clinic as an integral part of the hospital and would like to do as little as possible in these areas because their take is that people keep coming, going and soiling it. So it is cleaned only twice a day.
There are interventions and operations which could lead to spillage of blood, body fluids and spillage or overflowing of bio medical waste in these areas. This leads to the usage of a variety of disinfectants and cleaning agents on the patients, instruments and OTs. People coming in for deliveries and labour rooms tend to have more body fluids and more dirt than in any other area of the hospital. It is difficult to clean this area because of the volume of the patients in this area.
There are monitors on the shelf, machineries on the floor and tubes running and curtains all around which can accumulate dust and can be the potential source of bacteria, fungi, spores and microorganisms because of the very continuous nature of patient care in the ICU. It cannot be vacated randomly. Therefore certain strategies need to be devised to take care of this department. Patients succumb to their illnesses and are taken to the mortuary until the family takes control. Depending on the number of the patients, the load on the mortuaries can be tremendous particularly in government hospitals.
Visitors intervene with the housekeeping activity and are also likely to harm themselves by coming in contact with physical objects, electrical objects or body fluids, disinfectants, chemicals and other hazardous material that are used in the hospital.
Indian hospitals also have the problem of bed bugs. Bed bugs are very difficult to eliminate. Fumigation is not the solution as they do not live on the surface. They get into corners, crevices, mattresses, pillows, clothes etc. where no cleaning agent or disinfectant can reach. Any cleaning agent which we use to kill the bugs can just as likely kill the patient as well. Besides this, rats and mosquitoes are ubiquitous. Treated patients going outside fortunately carry their illnesses and bugs away with them but they leave behind bio medical waste, kitchen waste, food waste, general waste – cardboard cartons in which material comes to the hospital for pharmacies, general store, engineering store, construction material, paint and a spectrum of engineering residues which are being generally thrown in some corner of the corridor.
Cleaning/ Disinfection Protocols
Hospitals have various areas where patients & healthcare personnel are exposed to different kinds of risks of developing infection. Areas like the canteen & administration sections in the hospital have minimal exposure to infections. These areas are cleaned using detergents and water. OPDs and wards which house patients are also cleaned with detergent and water.
Disinfectants are used in areas where there is a spill of a body fluid. Isolation wards are areas where infected patients are admitted and detergents/disinfectants are used with separate cleaning equipment for each individual patient room.
The categories of risk involving patients when equipment are used include critical or high risk items, semi-critical or intermediate risk items and non-critical or low risk items. Critical items enter sterile areas in the body like the blood and hence carry a high risk of infection if they are contaminated. This category includes surgical instruments, cardiac, urinary catheters, implants and ultrasound probes used in sterile body cavities. Most of the items in this category are sterilized with steam if possible. Heat-sensitive objects can be treated with ethylene oxide, hydrogen peroxide gas plasma; or if other methods are unsuitable, by liquid chemical like >2.4% glutaraldehyde based formulations.
Semi-critical items come in contact with mucous membranes or non-intact skin. This category includes respiratory therapy and anesthesia equipment, some endoscopes, laryngoscope blades, esophageal manometry probes, cystoscopes , anorectal manometry catheters and diaphragm fitting rings. Semi-critical items minimally require high-level disinfection using chemical disinfectants. Glutaraldehyde, hydrogen peroxide, ortho-phthalaldehyde, and peracetic acid with hydrogen peroxide can be used for this purpose. Non- critical items are those that come in contact with intact skin but not mucous membranes. These items include bed pans, blood pressure cuffs, crutches and computers. They are de-contaminated after use.
Types of Disinfectants
Disinfectants can be divided into high level disinfectants, intermediate level disinfectants and low level disinfectants. High level disinfectants are chemicals which can destroy most micro-organisms but are unable to kill bacterial spores ex Glutaraldehyde & Orthophthaldehyde. Intermediate level disinfectants are able to kill Mycobacterium, most viruses and fungi. Low level disinfectants kill most vegetative bacteria, some viruses and some fungi. Examples of intermediate and low level disinfectants are Ethyl/Isopropyl alcohol and phenolic germicides.