Bloodborne Pathogens, Microbiology and Prions

Regulatory Protections and Infection Control Standards

Sterile processing technicians play an essential role in protecting patient safety and public health. Every day, technicians handle items used during invasive surgical procedures. The Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard was designed to protect healthcare workers from occupational exposure to blood and other potentially infectious materials. The primary bloodborne pathogens of concern in sterile processing are Hepatitis B Virus (HBV), Hepatitis C Virus (HCV), and Human Immunodeficiency Virus (HIV). To safeguard staff, healthcare facilities must maintain a written Exposure Control Plan that is reviewed and updated at least annually. In addition, employers must offer the Hepatitis B vaccination series free of charge to all employees who have potential occupational exposure.

Technicians manage contamination by applying proven infection control principles. Universal Precautions require treating all human blood and specific body fluids as if they are known to be infectious for bloodborne pathogens. Standard Precautions build upon this concept by combining Universal Precautions and Body Substance Isolation into a comprehensive infection control strategy applied to all patients regardless of their diagnosis. In sterile processing, technicians assume that every instrument entering the decontamination area carries infectious bioburden, ensuring identical, rigorous safeguards are always practiced.

Workplace safety relies on physical designs and specific behaviors. Engineering controls isolate or eliminate bloodborne pathogen hazards through physical design, such as rigid sharps containers that are puncture-resistant, leak-proof on the sides and bottom, and biohazard-labeled or color-coded. Biohazard labels must display the universal biohazard symbol and be colored fluorescent orange or orange-red. Work practice controls reduce exposure risk by altering the specific manner in which tasks are executed. For example, contaminated reusable sharps must never be gathered or transported by hand in ways that expose technicians to puncture risks. In the decontamination area, technicians must wear personal protective equipment (PPE) appropriate to the exposure risk and facility policy, typically including a fluid-resistant gown, heavy-duty utility gloves, and a mask with eye protection or a face shield, with shoe covers used when required. Hand hygiene must be performed immediately after removing gloves and other PPE.

Microbiology and the Hierarchy of Microbial Resistance

Understanding microbiology allows technicians to select the proper methods for cleaning, disinfection, and sterilization. Infectious diseases spread through a chain of infection consisting of six links: causative agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host. A reservoir is any person, animal, plant, soil, or substance in which an infectious agent normally lives and multiplies. Indirect contact transmission occurs when a susceptible host contacts a contaminated intermediate object, such as a soiled surgical instrument. Breaking any single link in the chain of infection successfully halts the spread of infectious disease, which is precisely what proper decontamination achieves.

Microorganisms display varying degrees of resistance to routine chemical disinfection and sterilization processes. Resistance generally ranges from highly resistant prions and bacterial endospores down to comparatively susceptible enveloped lipid viruses. Vegetative bacteria represent the actively metabolizing, reproducing state of bacteria and are relatively easy to kill with disinfectants. In contrast, bacterial endospores are the most resistant conventional microbial form capable of surviving extreme environmental stress. Certain species also have structural defenses; for example, Gram-positive bacteria have a thick peptidoglycan cell wall that retains crystal violet stain during laboratory analysis, while Gram-negative bacteria possess a thin peptidoglycan layer surrounded by an outer lipopolysaccharide membrane that blocks certain disinfectants. Mycobacteria possess a thick, waxy, lipid-rich cell wall that provides elevated resistance to chemical disinfection.

Viruses also show differing levels of vulnerability based on their structure. Enveloped lipid viruses, such as HIV and Hepatitis B, are among the most susceptible organisms to chemical inactivation because their lipid coat is easily disrupted. Non-enveloped viruses lack this lipid layer and are generally more resistant to disinfectants and environmental conditions. Because bacterial spores are exceptionally resilient, specific nonpathogenic species are used to test sterilization equipment. Geobacillus stearothermophilus spores serve as the standard biological indicators for monitoring steam, vaporized hydrogen peroxide, and ozone sterilization cycles. Bacillus atrophaeus spores serve as the standard biological indicators used to monitor ethylene oxide and dry heat sterilization cycles.

Biofilm Formation and the Cleaning Foundation

Decontamination is the physical or chemical process that renders a contaminated object safe for subsequent handling. Cleaning is the foundational step of decontamination because residual soil shields underlying microbes from sterilizing agents. If organic debris remains on a surgical device, sterilants cannot make direct contact with microorganisms, causing the sterilization process to fail. Think of encrusted surgical debris like dried food stuck inside a drinking straw; rinsing alone will not penetrate beneath the hardened layer.

Allowing blood and surgical debris to dry on instruments makes soil harder to remove and can contribute to persistent contamination. Microorganisms can begin adhering to soiled device surfaces within minutes, and an established biofilm develops over time. A biofilm is an organized community of microorganisms protected by a self-secreted matrix of extracellular polymeric substances. This matrix adheres tenaciously to moist inner surfaces, internal channels, and complex lumens of surgical instruments. The extracellular polymeric matrix shields inner bacteria from antimicrobials, chemical disinfectants, and sterilants. Thorough manual or mechanical cleaning is necessary to physically remove and disrupt biofilms prior to disinfection or sterilization.

Preventing biofilm begins immediately after surgery. Point-of-use pre-treatment is critical to prevent gross blood and bioburden from drying on instrument surfaces during transport. At the point of use, clinical staff may apply an instrument-compatible pretreatment spray, foam, or gel, according to the manufacturers' instructions and facility policy, to keep soil moist until cleaning. When permitted by the instrument's instructions for use (IFU) and facility policy, clinical staff may cover soiled instruments with a water-moistened towel to help prevent drying during transport. Saline solution should never be used to moisten or clean instruments because chloride ions cause pitting and corrosion of surgical steel.

Prion Diseases and Specialized Reprocessing

Prions represent a unique challenge that goes beyond ordinary bacterial and viral threats. Creutzfeldt-Jakob Disease (CJD) is a fatal transmissible spongiform encephalopathy affecting the human central nervous system. Prions are abnormally folded infectious proteins that replicate without containing DNA or RNA genetic material. Because they are not living organisms and lack foreign genetic material, prion diseases generally do not trigger a conventional inflammatory or antibody response in the host. Prions bind tightly to surgical stainless steel, which significantly increases their resistance to standard decontamination procedures.

The risk of prion transmission depends heavily on the patient tissue contacted during surgery. Brain, spinal cord, and posterior eye tissues are high-risk tissues for prion exposure. Dura mater also warrants special precautions because prion transmission has occurred through grafts. In contrast, urine, feces, saliva, and intact skin generally have low or undetectable prion infectivity; however, blood must not be considered noninfectious because variant CJD has been transmitted by transfusion. When instruments contact high-risk tissue in a suspected or confirmed CJD case, standard operating room and sterile processing routines are not sufficient.

Prions resist many routine disinfectants and sterilization cycles and require a facility-approved, device-compatible prion protocol. Ethylene oxide and hydrogen peroxide gas plasma are not considered reliable methods for decontaminating instruments exposed to high-risk prion tissue, and standard steam sterilization exposure cycles are inadequate for the complete destruction of prion infectivity. Reusable instruments exposed to high-risk tissue in suspected or confirmed CJD cases require a facility-approved prion reprocessing protocol consistent with applicable guidance and manufacturers' instructions; extended steam exposure alone may not be sufficient. A facility-approved prion protocol may combine a chemical such as sodium hydroxide or sodium hypochlorite with steam sterilization, but the chemicals and process must be compatible with the instruments and equipment.

Strict operational handling must be maintained from the moment a procedure concludes. Instruments exposed to high-risk tissue in a suspected or confirmed CJD case should be kept moist, segregated, and handled under facility policy until approved reprocessing or disposal. Drying prion-contaminated tissue on an instrument makes residue harder to remove and can reduce the effectiveness of prion decontamination. Facility policy may call for single-use instruments during procedures involving high-risk tissue in patients with suspected or confirmed CJD; sterile processing technicians must not reprocess them as reusable instruments. Ultimately, facility policy and infection prevention guidance determine whether instruments exposed to high-risk tissue are quarantined pending diagnosis, reprocessed under an approved prion protocol, or disposed of appropriately. Technicians must follow facility-approved prion protocols and applicable instrument, chemical, and sterilizer manufacturers' instructions for use, escalating any incompatibility rather than improvising a process.