Textbook of Diagnostic Microbiology - Chapter 4: Control of Microorganisms

CHAPTER 4 Control of Microorganisms: Disinfection, Sterilization, and Microbiology Safety 69 laboratories were lax. Mouth pipetting was a widely used technique, Describe the safe handling, storage, and disposal of chemicals and eating, drinking, and smoking i...

CHAPTER 4 Control of Microorganisms: Disinfection, Sterilization, and Microbiology Safety 69 laboratories were lax. Mouth pipetting was a widely used technique, Describe the safe handling, storage, and disposal of chemicals and eating, drinking, and smoking in the laboratory, although and radioactive substances. discouraged, were common. Beginning in the early 1980s, this Clearly outline the laboratory or hospital policies for correct relaxed attitude toward safety among personnel changed dramati- procedures in the event of fire, natural disasters, and bomb cally. The impetus behind the change was the arrival in the United threats. States of a previously unheard of disease with an apparent 100% Perform initial safety training for all employees in all aspects mortality rate. This disease became known as acquired immuno- of laboratory safety, and update training annually. deficiency syndrome (AIDS). In addition to being a global calamity, Teach correct techniques for lifting and moving heavy objects AIDS initiated a major rethinking of employee risk for laboratory- and patients. acquired infections (LAIs) in hospitals around the United States. The safety program needs to be ongoing and consistent with Beginning with an emphasis on reducing the risks of biological current federal and state regulations. Most important, it must be hazards (biohazards), safety became a priority for laboratory presented in a way that encourages employees to incorporate the personnel. The attitude of “What you don’t know can’t hurt you,” safety practices into their daily routines and take responsibility common among laboratory employees, rapidly went out of date. for keeping the work environment safe. Safety in the clinical laboratory is a major concern, and work practices need to be continually reevaluated. Studies have shown Occupational Safety and Health Administration laboratorians are at increased risk of infections compared with Laboratorians must always remember that they work in a hazardous the general population. Laboratory exposures do occur, and often environment. Hazards can be classified as biological, chemical, they cannot be traced back to a specific event. In 2012 the CDC radiologic, or physical. Training programs are instituted in all of published “Guidelines for Safe Work Practices in Human and these areas for employees who are exposed to any of these hazards. Animal Medical Diagnostic Laboratories” in the Morbidity and It is imperative for the individual to follow the rules that are set Mortality Weekly Report, Supplement. This report was developed forth in the safety procedure manuals. to improve safety in the laboratory by increasing safe practices, The mission of the OSHA is to protect workers within the to encourage laboratorians to consider safety issues, and to foster United States. The clinical laboratory falls under these regulations. a culture of safety. Safety in the clinical laboratory encompasses In 1991 the OSHA created and released the Bloodborne Pathogens biological, chemical, electrical, radioactive, and fire hazard Final Standard to protect health care workers. This standard was protection. revised in 2001 in conformance with Public Law 106-430, the Needlestick Safety and Prevention Act. General Laboratory Safety Exposure Control Plan Safety in the clinical laboratory is the responsibility of the institu- The OSHA Bloodborne Pathogens Standard clearly states the tion, laboratory directors, laboratory managers and laboratory safety requirements that the employer must have in place to protect employees. Laboratory employees must be provided with a safe the employee from bloodborne pathogens. Employers are required work environment. Laboratory directors, managers, and employees to have an exposure control plan, which must be reviewed and must know the current safety regulations; safety procedure manuals updated annually. This plan must be available to all employees must be provided; and training in safe laboratory practices must and should include the following: occur on an annual basis through in-service education and should A determination of tasks and procedures that may result in an be the duty of an assigned safety officer. Although the provision occupational hazard of a safe work environment is ultimately the employer’s responsibil- A plan to investigate all exposure incidents and a plan to prevent ity, it cannot be achieved without the commitment of all persons these from reoccurring in that environment to practice safe techniques for their own and Methods of compliance for standard precautions their coworkers’ protection. Engineering and work practice controls Personal protective equipment (PPE) Case Check 4.2 Guidelines for ensuring that the work site is maintained in a clean and sanitary manner The Case in Point at the beginning of this section illustrates the importance Guidelines for the handling and disposal of regulated of a safety program for the clinical laboratory. Safety in the laboratory is the responsibility of all laboratory personnel. All people who come waste through the laboratory must also observe the safety guidelines to ensure A training program for all employees proper protection and reduce risk of exposure to potential hazardous biological agents. Standard Precautions In 1985 the CDC instituted safety guidelines for the handling of blood and body fluids. These guidelines, called universal precau- Safety Program for the tions, were intended to protect hospital personnel from bloodborne Clinical Laboratory infections. In 1996 these guidelines were updated and renamed. The comprehensive safety program for the clinical laboratory These new guidelines, standard precautions, are still in effect. needs to fulfill the following: These guidelines require that blood and body fluids from all patients Address biological hazards by performing biological risk be considered infectious and capable of transmitting disease. Blood assessments and developing safety procedures for working and all body fluids, including secretions and excretions except with these hazards. sweat, regardless of whether visible blood is present, are considered 70 PART 1 Introduction to Clinical Microbiology infectious. Standard precautions also include nonintact skin and laboratory equipment, the use of safety needles and single-use mucous membranes. holders, eyewash stations, emergency showers, and plastic shield To ensure that the guidelines required in standard precautions barriers. Ideally, laboratories should have negative air pressure, are followed within the laboratory, engineering controls and work access to the laboratory should be limited, and there should be a practice controls are instituted, and employers must provide PPE. plan to prevent insect infestation. Standard precautions address the following: Handwashing must be done after touching blood, body fluids, Work Practice Controls secretions, excretions, and any items considered contaminated. Altering the manner in which a task is performed to reduce the Hands must be washed after removal of gloves and between likelihood of exposure to infectious agents is defined by the OSHA patients. as work practice controls. Examples of work practice controls Gloves should be worn when handling blood, body fluids, include the following: secretions, excretions, and any items considered contaminated. No mouth pipetting Clean gloves must be put on before touching mucous membranes No eating, drinking, smoking, or applying cosmetics in the and nonintact skin. Hands must be washed after removal of laboratory gloves. Disinfection of workstations at the end of each shift and after Mask, eye protection, or face shield must be worn anytime any spill of infectious material there is a potential for splashes or sprays of blood, body fluids, No recapping or breaking of contaminated needles secretions, and excretions. Disposal of needles in an appropriate puncture-resistant Laboratory coats must be worn to protect skin and clothing container when contact with blood, body fluids, secretions, and excretions Procedures performed in a manner that minimizes splashing could occur. and the generation of air droplets Appropriate sharps disposal must be implemented with care Specimens transported by way of well-constructed containers to prevent injuries with sharps, needles, and scalpels. These with secure lids to prevent leakage of infectious materials devices must be placed in appropriate puncture-resistant contain- Frequent handwashing ers after use. Environmental control must include procedures for routine Personal Protective Equipment care, cleaning, and disinfection of environmental surfaces. Specialized clothing or equipment that is worn by an employee for protection is defined by the OSHA as personnel protective Transmission-Based Precautions equipment (PPE). PPE must be provided and maintained by the The second set of precautions for the health care setting are called employer; examples include gloves, laboratory coats, masks, transmission-based precautions. Standard precautions are still respirators, face shields, and safety glasses. For PPE to be protective followed, and transmission-based precautions are added precau- and considered appropriate, blood and body fluids must not be tions that are used when the patient is known or suspected to be able to penetrate the PPE material. The equipment must be acces- infected or colonized with an infectious agent that requires extra sible to the employee and must be worn whenever there is the measures to prevent spread or transmission of the agent. The potential for exposure to infectious material; it must be removed categories of these precautions are contact precautions, droplet before leaving the work area and must be placed in an area precautions, and airborne precautions. Contact precautions are used designated for PPE. Gloves should be removed whenever they to stop the spread of infectious agents that may be transmitted become contaminated, and disposable gloves should never be through direct or indirect contact with the patient or with the washed and reused. Hands must be washed after the removal of patient’s environment. Examples of these types of infectious agents gloves. are multidrug-resistant organisms such as vancomycin-resistant PPE must fit properly to be the most effective. Respirators enterococci, MRSA, and Clostridium difficile. that are used for protection against airborne transmission of Droplet precautions are used to stop the spread of infectious infectious agents must be fit-tested to ensure the protection of the agents that can be transmitted by close respiratory contact or by worker. Fig. 4.3 illustrates goggles, masks, and laboratory garments exposure of mucous membranes to respiratory secretions. Examples appropriate for use in laboratory workstations. of infectious agents that can be transmitted by this route include Neisseria meningitidis, Bordetella pertussis, and influenza virus. Biological Risk Assessment The final category is airborne precautions. These precautions are For an infection to occur, including an LAI, there must be a used for infectious agents, such as M. tuberculosis, varicella virus, susceptible host, the infectious agent must have a route of transmis- and rubeola virus, that can remain airborne and infectious over sion to the susceptible host, and the concentration of the agent long distances. For further information on what safety procedures must be high enough to cause disease. The biological hazards should be used for each category of precautions, refer to the 2007 in the microbiology laboratory come from two major sources: Guideline for Isolation Precautions: Preventing Transmission of (1) processing of the patient specimens and (2) handling of the Infectious Agents in Healthcare Settings published by the CDC. actively growing cultures of microorganisms. Either activity puts the employee at risk of potential contact with infectious agents. Engineering Controls The major routes of LAIs in the clinical laboratory are parenteral Engineering controls are defined by the OSHA as controls that inoculations (e.g., needlesticks or contaminated sharps), spills and isolate or remove the hazard from the workplace. Examples of splashes onto skin or mucous membranes, ingestions (e.g., putting engineering controls include the use of closed tube sampling by pens or fingers into the mouth, mouth pipetting), and inhalation 72 PART 1 Introduction to Clinical Microbiology through a needlestick injury or another percutaneous route. All these infectious agents must be handled with extreme care. BOX 4.2 Classification of Infective Microorganisms Because microbiology laboratory personnel frequently deal by Risk Group with various infectious agents—viral, fungal, bacterial, parasitic, Risk Group 1 (No or Low Individual and and mycobacterial—LAIs are an obvious hazard and should be Community Risk) a concern for all laboratorians. All laboratorians must understand A microorganism that is unlikely to cause human or animal disease. that they are at risk of an LAI because of the environment in Risk Group 2 (Moderate Individual Risk, Low which they work, and it should be the goal of laboratory manage- Community Risk) ment and laboratory workers to minimize this risk and follow all A pathogen that can cause human or animal disease but is unlikely to of the safety procedures employed by the laboratory for their be a serious hazard to laboratory workers, the community, livestock, protection. A more recent example of the risk to laboratorians or the environment. Laboratory exposures may cause serious infection, and their family members of LAIs was an outbreak of Salmonella but effective treatment and preventive measures are available, and the risk of spread of infection is limited. typhimurium infections. Between August 2010 and June 2011, 109 individuals were infected with this organism in over 38 states. Risk Group 3 (High Individual Risk, Low An epidemiologic study was conducted, and one possible link Community Risk) identified was exposure to microbiology laboratories, including A pathogen that usually causes serious human or animal disease but does not ordinarily spread from one infected individual to another. teaching laboratories and clinical laboratories. The CDC, along Effective treatment and preventive measures are available. with other organizations, identified areas where biosafety and laboratory safety improvements should be made. Some of the Risk Group 4 (High Individual and Community Risk) A pathogen that usually causes serious human or animal disease and recommendations for students, laboratorians, laboratory directors that can be readily transmitted from one individual to another, directly and managers, and faculty included the following: or indirectly. Effective treatment and preventive measures are not usually 1. Laboratorians and students should know that the bacteria handled available. in the laboratory can make people sick. These organisms can From World Health Organization: Laboratory biosafety manual, ed 3, Geneva, also make family members sick. Individuals must not take Switzerland, 2004, World Health Organization. items into the laboratories that will be taken home, such as laboratory coats, pens, books, laboratory report forms, cell phones, and keys. biosafety levels (BSLs) discussed later in this chapter, but are 2. Students should have dedicated writing utensils and supplies at not always equal (Box 4.2). Other factors that must be considered their work stations, and these should not leave the laboratory. when one is determining the correct BSL needed are the mode 3. Laboratorians and students must be aware of the organisms of transmission, the microbiological procedures that will be with which they are working and what the signs and symptoms performed, and the experience of the staff members. A biological are if they get infected with one of these organisms. risk assessment is a comprehensive attempt to determine what 4. Laboratorians and students must be trained and proficient in controls should be used to protect the worker and environment biosafety practices and techniques. from exposure. It is a subjective process, and different strategies 5. Laboratory coats should always be worn over personal clothing can be used to perform the assessment. Five steps have been (appropriate PPE should be worn). Individuals should not leave outlined in the CDC’s “Guidelines for Safe Work Practices in the laboratory with PPE on; PPE always should be disposed Human and Animal Medical Diagnostic Laboratories” for perform- of properly. ing a risk assessment. These are as follows: 6. Handwashing sinks and supplies must be provided. Laborato- 1. Identify the hazards associated with an infectious agent or rians and students should always wash their hands before leaving material. the laboratory. 2. Identify the activities that might cause exposures to the agent Biological risk assessment is an important part of every or material. microbiology laboratory safety program. Biological risk assessment 3. Consider the competencies and experience of laboratory is a process used to recognize the hazardous characteristics of personnel. infectious agents that may be encountered in the clinical microbiol- 4. Evaluate and prioritize risks (evaluate the likelihood that an ogy laboratory. Also included in the risk assessment process are exposure would cause an LAI and the severity of consequences the laboratory practices that could result in an infectious exposure, if such an infection occurs). the likelihood that an LAI will occur, and the consequences of 5. Develop, implement, and evaluate controls to minimize the that infection. Through this process, appropriate safety practices risk for exposure.* can be identified to protect laboratorians. The hazardous risk characteristics of an agent are determined Processing of Patient Specimens by the agent’s ability to infect and cause disease in humans or Labeling only specimens from patients with known hepatitis or animals; its virulence; the availability of treatment for the disease; AIDS and requiring “extra precautions” for dealing with these and whether there are any preventive measures, such as a vaccine, that can be used to prevent disease by the microorganism. The World Health Organization (WHO) defined four risk groups for *From Department of Health and Human Services, Centers for Disease Control and Prevention: Guidelines for safe work practices in human and animal medical infectious agents based on the hazardous characteristics listed diagnostic laboratories. MMWR Suppl 61(01) January 6, 2012, p.1, Available at: previously. The four risk groups, defined in the WHO classification https://www.cdc.gov/mmwr/preview/mmwrhtml/su6101a1.htm?s_cid=su6101a1_w. of infectious microorganisms by risk group, correlate with the Accessed Oct. 2, 2017.