Asepsis is the state of being free fromdisease-causing micro-organisms (such aspathogenic bacteria,viruses,pathogenic fungi, andparasites).[1] There are two categories of asepsis: medical and surgical.[1] The modern day notion of asepsis is derived from the olderantiseptic techniques, a shift initiated by different individuals in the 19th century who introduced practices such as the sterilizing of surgical tools and the wearing of surgical gloves during operations.[2] The goal of asepsis is to eliminate infection, not to achieve sterility.[1] Ideally, anoperating field issterile, meaning it is free of all biological contaminants (e.g. fungi, bacteria, viruses), not just those that can cause disease,putrefaction, orfermentation.[1] Even in an aseptic state, a condition of sterile inflammation may develop. The term often refers to those practices used to promote or induce asepsis in an operative field ofsurgery ormedicine to preventinfection.[3]
The modern concept of asepsis evolved in the 19th century through multiple individuals.Ignaz Semmelweis showed already in 1847–1848 thathand washing prior todelivery reducedpuerperal fever. Despite this, many hospitals continued to practice surgery in unsanitary conditions, with some surgeons taking pride in their bloodstained operating gowns.[4]
Only a decade later the situation started to change, when some French surgeons started to adoptcarbolic acid as an antiseptic, reducing surgical infection rates, followed by their Italian colleagues in the 1860s.[5] In 1867Joseph Lister explained this reduction byLouis Pasteur'sgerm theory and popularized the disinfectant in the English-speaking world.[6]
Giuseppe Ruggi [it] shifted the movement then from antisepsis to asepsis in the 1870s, publishing his findings in 1879.[7]Gustav Adolf Neuber introduced sterile gowns and capes in 1883, and in 1891,Ernst von Bergmann introduced theautoclave, a device used for the practice of the sterilization of surgical instruments.[8]
Rubber gloves were pioneered byWilliam Halsted, who also implemented a no street clothes policy in his operating room, opting to wear a completely white, sterile uniform consisting of a duck suit,tennis shoes, andskullcap.[2] This helped to prevent the introduction of infections into open wounds.[2] Additionally, Halsted would sterilize the operation site with disinfectants and use drapes to cover all areas except for the site.[2] In his department atJohns Hopkins Hospital, he enforced an extreme hand washing ritual consisting of soaking in harmfully strong chemicals likepermanganate andmercury bichloride solution as well as scrubbing with stiff brushes.[2] The damage to a surgical nurse's hands compelled him to create the earliest form of thesurgical gloves with theGoodyear Rubber Company.[2] These gloves became a part of the aseptic surgery standard when Dr.Joseph Colt Bloodgood and several others began wearing them for that particular purpose.[9]
The line between antisepsis and asepsis is interpreted differently, depending on context and time.[6] In the past, antiseptic operations occurred in people's homes or in operating theaters before a large crowd.[6] Procedures for implementing antisepsis varied among physicians and experienced constant changes.[6] Until the late 19th century, physicians rejected the connection between Louis Pasteur'sgerm theory that bacteria caused diseases and antiseptic techniques.[10] At the end of the 19th century, Joseph Lister and his followers expanded the term "antisepsis" and coined "asepsis", with the justification that Lister had initially "suggested excluding septic agents from the wound from the start."[6] Generally, however, asepsis is seen as a continuation of antisepsis since many of the values are the same, such as a "germ-free environment around the wound or patient", and techniques pioneered under both names are used in conjunction today.[6]
Asepsis refers to any procedure that is performed under sterile conditions. This includes medical and laboratory techniques (such as withbacterial cultures). There are two types of asepsis — medical and surgical.[1] Medical or clean asepsis reduces the number of organisms and prevents their spread; surgical or sterile asepsis includes procedures to eliminatemicro-organisms from an area and is practiced bysurgical technologists and nurses.[1] Ultimately, though, successful usage of aseptic operations depends on a combination of preparatory actions.[11] For example, sterile equipment and fluids are used during invasive medical and nursing procedures.[11] The largest manifestation of such aseptic techniques is in hospitaloperating theaters, where the aim is to keep patients free fromhospital micro-organisms.[12]
While all members of the surgical team should demonstrate good aseptic technique, it is the role of thescrub nurse orsurgical technologist to set up and maintain the sterile field.[13][14] To prevent cross-contamination of patients, instruments are sterilized throughautoclaving or by using disposable equipment;suture material orxenografts also need to be sterilized beforehand.[15] Basic aseptic procedures includes hand washing, donning protective gloves, masks and gowns, and sterilizing equipment and linens.[12] Medical aseptic techniques also includes curbing the spread ofinfectious diseases through quarantine, specifically isolation procedures based on the mode of disease transmission.[12] Within contact, droplet and airborne isolation methods, two different procedures emerge: strict isolation vs. reverse isolation.[12] Strict isolation quarantines patients to prevent them from infecting others, while reverse isolation prevents vulnerable patients from becoming infected.[12]
In aseptic conditions, a "chronic low-level inflammation" known as sterile inflammation may develop as a result of trauma, stress, or environmental factors.[16] As in infections caused by pathogens or microbes, the immune response is regulated by host receptors.[3] Tissue damage resulting from non-infectious means are caused byDAMPs molecules released after injury or cell death has occurred, which are able to stimulate inflammation response.[3] Diseases associated with sterile inflammation includeAlzheimer's disease,atherosclerosis, as well as cancertumor growth due to "immune cell infiltration."[3] Additionally, aseptic tissue damage may arise fromcorticosteroid injections, which are drugs used to treat musculoskeletal conditions such ascarpal tunnel andosteoarthritis, though this tends to result from improper aseptic technique.[17][18]
Despite efforts to preserve asepsis during surgery, there still persists a 1-3% chance of asurgical site infection (SSI).[19] Infections are categorized as superficial incisional, deep incisional, or organ; the first type are confined to the skin, the second to muscles and nearby tissues, and the third to organs not anatomically close to the operation site.[19][20] The exact modes of infection depend on the types of surgery, but the most common bacteria that are responsible for SSIs areStaphylococcus aureus, coagulase-negative staphylococci,Escherichia coli, and Enterococcus spp.[21] TheCDC emphasizes the importance of both antiseptic and aseptic approaches in avoiding SSIs, especially since Staphylococcus aureus, among other bacteria, are able to evolve drug-resistant strains that can be difficult to treat.[22] In 2017, nearly 20,000 patients in the United States died from Staphylococcus aureus in comparison to the 16,350 from diagnosed HIV.[23][24]