History of Antisepsis, Asepsis and Surgical Disinfection

Antisepsis, Asepsis and Disinfection: Key Concepts

Antisepsis: lowers organic surface microbial load; it is non-toxic to skin and mucosa and inhibits bacterial growth without preserving the sterility of the environment. Asepsis: the absence of pathogenic microorganisms in materials and environments.

Disinfection: destruction of pathogenic microorganisms on inorganic materials. Sterilization: destruction or elimination of all forms of microbial life, including their spores.

Methods of Sterilization

Physical methods: moist heat, dry heat, filtration and radiation.

Chemical methods: sterilization with gaseous agents (organic and inorganic).

• Protein coagulation: proteins precipitate and enzymatic activity stops, so cells die.
• Oxidation of free sulfhydryl groups: sulfhydryl groups are fixed by an oxidizing agent and the cell dies.
• Enzymatic antagonism: inhibits cell reproduction by occupying receptors.
• Membrane rupture: the cell membrane breaks open.

Germicides, Sanitizers and Tyndallization

Germicides inactivate viruses and protozoa but do not affect spores of bacteria and fungi. Sanitizers reduce the number of microorganisms to an officially accepted safe level.

Tyndallization is intermittent sterilization by heating at 80 to 100 °C for 24 hours, repeated over several days to kill spores that develop into new cells.

Disinfectant Testing Coefficients

Phenol coefficient: compares a disinfectant with phenol, using Salmonella typhi as the test organism. A coefficient above 1 means the disinfectant is more effective than phenol.

• Inhibition coefficient: the dilution of disinfectant that completely inhibits bacterial growth in a nutrient broth.
• Lower limit coefficient: the dilution of disinfectant that, over a shorter time, does not kill the microorganism.
• Upper limit coefficient: the dilution of disinfectant that kills the microorganism within a given time.

Chemical Agents

Organic Agents

• Alcohol: used as a skin antiseptic. 70% alcohol is the common disinfectant concentration.
• Aldehydes: dehydrate and denature proteins. Formalin (formaldehyde): 8% formalin and 70% alcohol are used. Gaseous formaldehyde is bactericidal, sporicidal and virucidal (e.g., polio), and it polymerizes collagen-preserved tissue.
• Glutaraldehyde: in alkaline aqueous solution it is bactericidal, sporicidal, tuberculocidal, virucidal and fungicidal. It is useful for endoscopes.
• Phenols: the first antiseptic (Lister). They coagulate bacterial proteins, denature cellular proteins and break the cell membrane.
• Organic acids: mandelic acid and methenamine mandelate are urinary tract antiseptics, but they may cause gastric irritation when taken orally.
• Anionic detergents: soaps, and sodium and potassium salts, act as surfactants.
• Cationic detergents: ammonium compounds are bactericidal against Gram-positive bacteria but not against spores, tubercle bacilli or many viruses. Cetrimide (cetyltrimethylammonium bromide) and benzalkonium chloride damage the cell membrane and are effective in alkaline pH. They are used as antiseptics and disinfectants but fail as chemical sterilants.
• Essential oils: terpenes and camphor (menthol).
• Dyes: triphenylmethane dyes (brilliant green, crystal violet, gentian violet, malachite green) and thionine (methylene blue) are bactericidal against Gram-positive bacteria but not spores.
• Nitrofurans: nitrofurantoin is a urinary antiseptic effective against Enterobacteriaceae. Furazolidone treats infections caused by Gram-negative organisms. Nitrofurans are combined with nitroquinoline in ointments.

Inorganic Agents

• Halogens: iodine (Betadine or povidone-iodine) is the first-choice antiseptic in surgery. Iodine, Isodine and Germidine are related preparations. Chlorine (sodium hypochlorite) is a highly bactericidal disinfectant effective against HIV and hepatitis viruses. At 1% it oxidizes membranes, but it does not kill tuberculosis bacilli.
• Oxidizing agents: they interfere with anaerobic metabolism and are only weakly bactericidal. Hydrogen peroxide (H₂O₂) releases oxygen, producing effervescence that mechanically cleans wounds. Potassium permanganate forms purple crystals; a 1:10,000 solution is used for wounds, and foot baths use 1 g in 10 L of water.
• Heavy metal salts: mercury, silver and zinc compounds are disinfectants and antiseptics. They act on sulfhydryl groups and coagulate proteins.
  • Thimerosal: bactericidal against many but not all organisms (not spores). It is a second-choice preoperative antiseptic and is slightly toxic, used in proctology.
  • Copper sulfate: used to treat wound infections caused by Gram-positive bacteria.
  • Silver nitrate (AgNO₃): 0.5% solution is bacteriostatic and used in ophthalmology to prevent gonococcal ophthalmia neonatorum.
  • Zinc sulfate (ZnSO₄): an ophthalmic antiseptic used to treat conjunctivitis.
• Boric acid: soluble in water; boric powder (10%) is used in dermatology and for ulcers, and as a conjunctival antiseptic.

Historical Foundations of Surgery

Ancient and Classical Medical Texts

• Ebers Papyrus: therapeutic prescriptions and general pathology, including cardiovascular conditions.
• Edwin Smith Papyrus: dislocations, head injuries and fractures.
• Kahun Papyri: gynecology and obstetrics.
• Hippocrates: author of the Corpus Hippocraticum (joints, fractures, head injuries, hemorrhoids and fistulas).
• Herophilus: studied the prostate, duodenum, hyoid bone and eye.
• Erasistratus: described the anatomy of the nervous system.
• Cornelius Celsus: described the four classic signs of inflammation and circulatory anatomy and physiology up to his time.
• Indian medicine: Charaka wrote the Charaka Samhita, and Sushruta wrote the Sushruta Samhita, which describes 121 surgical instruments and rhinoplasty (reconstructive plastic surgery). Narcotics such as bhang (Indian hemp) were used for surgery.
• Oribasius, Aetius and Paul of Aegina: described lithotomy, hernias, purulent pleurisy, tonsillectomy and breast amputation.
• Avicenna and Averroes: transcribed and commented on the work of Hippocrates.
• Maimonides: reconciled biblical teaching and Aristotelian philosophy in medical practice.
• Tlamatinime and Ticitl: Aztec healers practiced surgery and public health surveillance. Ticitl was a healer of the Mexica people.

Medieval Surgery

Surgery in medieval Europe was often considered barbaric and was largely carried out by barber-surgeons under the authority of the Church. Medical schools were established at Montpellier, Paris, Nuremberg, Padua and Salerno. Roland of Parma's school taught that suppuration was laudable: wounds were treated with ointments so that pus would drain and the wound would heal.

• Lanfranc of Milan (13th century): Chirurgia Magna (1296), describing esophageal intubation, intestinal suturing and cranial trepanation.
• Guy de Chauliac: a student of Bologna who dissected human cadavers.
• John of Vigo and Johannes Mondino: dissected human bodies.
• Ypres and Jan Yperman: performed autopsies (1316) and published the first anatomy text of the Renaissance.
• Vesalius: the greatest anatomist of the Renaissance, who wrote On the Fabric of the Human Body and is regarded as the founder of modern humanist anatomy.

Seventeenth and Eighteenth Centuries

• Leeuwenhoek: used early microscopes to observe bacteria, red blood cells, sperm and cilia.
• William Harvey: the father of circulatory physiology, who described blood circulation.
• John Mayow: pioneered respiratory physiology.
• Zambeccari: conducted experimental surgery on dogs.
• Ambroise Paré (1510 to 1590): the father of surgery. He used ligatures to control arterial bleeding instead of cautery, and his book on gunshot wounds was widely used.
• Jacques Guillemeau (1536): wrote Major Surgery.
• Fabricius of Hildanus: a German surgeon who pioneered arterial ligation for aneurysms.
• Cagni (18th century): studied lymphatics.
• Douglas: studied the peritoneum.
• Clinical surgery: systematic study of disease through clinical observation.
• Topographic anatomy: Scarpa, Lieutaud, Hunter and the Pitt brothers, and Jean-Louis Petit and Desault, who taught clinical practice.
• Histopathology: Morgagni and Bichat linked the cause and effect of diseases.
• Physiology: Albrecht von Haller, Réaumur, Hales, Priestley and Lavoisier.

Nineteenth Century Advances

• First ambulance: introduced around 1792 to provide first aid on the battlefield.
• Early surgeons: Cooper (without anesthesia), Langenbeck (without cadavers), Dieffenbach and von Graefe (radiologist), and Mac Dowell, who removed an ovary.
• Nélaton and Velpeau: orthopedics, and Pirogoff's surgery.
• Dupuytren: experimental and descriptive surgery (anatomo-clinical method).

Anesthesia

Dioscorides used wine as an anesthetic, and Roland of Parma used sponges soaked in soporific substances. Assyrians compressed the carotid arteries to induce unconsciousness. In 1776, Priestley discovered nitrous oxide (N₂O), known as laughing gas. Horace Wells (a dentist) used it in patients. William T. G. Morton (a dentist) used ether as an anesthetic following Wells, in London (1855), Edinburgh (1862) and Paris (1864). The first surgeons operated on the abdomen under anesthesia.

Koeberle used clamps for hemostasis and rubber gloves were not yet used. Hands did not touch the wound.

Hygiene and Antisepsis

The first hygienic standards and the focus on preventing infection led to the use of clean instruments and handwashing before surgery. Hands were sterilized by introducing them into a chlorinated solution, and the instruments were cleaned.

• Ignaz Semmelweis: recommended handwashing before surgery and reduced puerperal fever.
• Louis Pasteur (1822 to 1895): demonstrated the existence of microorganisms and the germ theory of disease.
• Joseph Lister: developed the antiseptic method, using carbolic acid (phenol) and later iodoform (1878), to prevent surgical infection.
• Pasteur and heat sterilization: sterilization by heat.
• Bergmann and Halsted: autoclaves and rubber surgical gloves (1885).
• Modern surgical specialties: ophthalmology, otolaryngology and urology.
• Koller (ophthalmologist, 1884): first used local anesthesia.
• Sauerbruch: modern thoracic surgery.

Postoperative Support

Supportive measures include intravenous fluids, analgesics, antibiotics, blood transfusions and anticoagulants.