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Chemical Methods of Control: Health Care Conditions in the 1800s

Explore the poor health care conditions in the 1800s and the chemical methods of control that revolutionized medical practices. Learn about the use of antiseptics, disinfectants, and important chemical agents.

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Chemical Methods of Control: Health Care Conditions in the 1800s

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  1. MICROBIOLOGY – ALCAMO LECTURE: Chemical Methods of Control

  2. Health Care Conditions in the1800’s • Hospitals rarely had running water • Garbage and human waste were dumped in a pit right outside • Surgeons wiped their hands and instruments on their jackets and pants • Bed sheets were rarely changed and infection was rampant • 1/3 of women giving birth died of puerperal fever – blood disease caused by Streptococcus

  3. Health Care Conditions in the1800’s • A Hungarian doctor – Ignaz Semmelweis – noticed: • More puerperal fever in maternity wards tended by doctors fresh from dissecting cadavers • Less puerperal fever in maternity wards tended by midwives • He thought disease was spread by infected hands and made hospital workers wash their hands • This reduced the death rate among maternity patients significantly

  4. Health Care Conditions in the1800’s • Other doctors rejected Semmelweis’s conclusions because it put the blame on them • After he died, Pasteur came out with the germ theory of disease • Doctors began to finally realize that infectious MO’s could be transmitted by clothing, utensils and instruments • They began using chemical antiseptics and disinfectants and the death toll declined

  5. Health Care Conditions in the1800’s • In the 1860’s Joseph Lister established the principles of aseptic surgery • He used carbolic acid to kill MO’s in operating rooms • Reduced the death rate post-surgery from 45% to 9%

  6. Lister Video • http://www.mefeedia.com/news/29703360

  7. Chemical Agents of Control – Terms To Know • Most chemical agents can only reduce the # of MO. Sterility is unusual. • Two Categories: • Antiseptics: Use on living tissues - mild or very diluted chemicals • Disinfectants: Use on objects – strong or concentrated chemicals

  8. Chemical Agents of Control - Terms To Know • Bactericidal Agent – kills MO’s • Bacteriostatic Agent – temporarily prevents further multiplication of MO’s without killing them • Sepsis (putrid) – contamination of an object by MO’s: • Septicemia – MO infection of the blood • Antiseptic – against infection • Aseptic – free of contaminating MO’s

  9. Chemical Agents of ControlTerms To Know • Sanitize – to reduce the MO population to a safe level determined by public health standards • Degerm – to remove MO’s from the surface • - cidal agents – kill Mo’s: • Fungicide • Virucide • Sporicide

  10. What Makes a Good Disinfectant • It must kill MO’s • Be nontoxic to humans and animals • Be soluble in water • Get its job done in a short time • Should penetrate surfaces well • Should not corrode instruments • Should be inexpensive and easy to obtain

  11. Important Chemical Agents - Halogens • Halogens are highly reactive elements whose atom have 7 electrons in their outer shell • Chlorine and Iodine – Very Reactive • Cause Cell Death by Oxidation – • Oxygen is released and then combines with and inactivates proteins (enzymes)

  12. Important Chemical Agents - Halogens • Chlorine • Disinfectant that can be used alone as gas or in a solution with water • Used in municipal water supplies to keep bacterial populations low • 6 – 10 Drops/Gal Clear Water/1 hour = Drink • Available as calcium hypochlorite – used for wounds in WWI and WWII

  13. Important Chemical Agents - Halogens • Available as sodium hypochlorite – bleach to disinfect water (swimming pools) and sanitize factory equipment • Laundry bleach most available and excellent means of MO control • Do not combine bleach with other chemicals - small but lethal amounts of Cl gas may be released!!!!

  14. Important Chemical Agents - Halogens • Chlorine is effective against • Gram-positive and Gram-negative bacteria • Many viruses • Fungi • Protozoa • Not effective against spores

  15. Important Chemical Agents - Halogens Iodine • Usually an antiseptic • 2% in water or alcohol (Tincture) good for wounds • If solvent evaporates tissue damage • For water disinfection use 18 – 20 Drops/Gal Clear Water/1 hour = Drink • Iodifors – iodine mixed with detergent • Betadyne – for local wounds

  16. Important Chemical Agents - Phenol • Has been a key disinfectant since Joseph Lister used it • Remains the standard against which other disinfectants are evaluated • It acts by coagulating proteins in the cell membranes of MO’s • But, it is expensive, has a strong odor, and is caustic to the skin

  17. Important Chemical Agents - Alcohol • Either antiseptic or disinfectant • 70% Ethyl alcohol preferred • Causes denaturation and desiccation • But requires long exposure, limited effect

  18. Important Chemical Agents - Heavy Metals • Metal elements with a large molecular weight: • Silver, Mercury, Copper, Lead, Zinc • Can be used as either an antiseptic or a medicine • Cause denaturation of proteins (enzymes) • Can be very toxic to host

  19. Important Chemical Agents - Heavy Metals • Mercury: • Mercuric chloride was used by the Greeks and Romans for treating skin diseases • Mercury is very toxic to the host, so it is now combined with carrier molecules to make it less toxic • Mercurochrome • Merthiolate • Metaphen

  20. Important Chemical Agents - Heavy Metals • Copper: • Potent inhibitor of algae • Copper sulfate is an algaecide used in swimming pools and municipal water supplies

  21. Important Chemical Agents - Heavy Metals • Silver: • Silver Nitrate – useful antiseptic and disinfectant • If it is a strong dilution – used for chemical cautery • If it is a weak dilution – used in a newborn’s eyes to prevent bacterial infection by Neisseria gonorrhoeae • Zinc: Calamine Lotion (antiseptic, anti-itch) • Bismuth: Pepto Bismol (anti-diarrheal)

  22. Important Chemical Agents Hydrogen Peroxide • Antiseptic and disinfectant – used as a rinse in wounds and scrapes • Area foams as catalase in tissues breaks down H2O2 to oxygen and water • This results in a highly reactive form of oxygen – toxic to MO’s

  23. Important Chemical Agents - Soap • Soap is made of fatty acids combined with sodium hydroxide – high pH bad for certain MO’s • Soap is also a wetting agent that solubilizes particles clinging to a surface • Soap also removes skin oils and MO’s slide off skin

  24. Soaps Video • http://www.google.com/url?sa=t&source=video&cd=9&sqi=2&ved=0CH8QtwIwCA&url=http%3A%2F%2Fvideo.google.com%2Fvideoplay%3Fdocid%3D-3210455528645505714&rct=j&q=chemical%20disinfection&ei=gXSjTc-QPMi-0QGAlaDQBA&usg=AFQjCNH14lMibDqfMas5Nz5ZNV34-Y9njg&cad=rja

  25. Important Chemical Agents - Ethylene Oxide • A small compound with excellent penetration capacity and sporicidal ability due to oxidation • Very Dangerous – toxic and explosive • Used in production of sterile supplies and by NASA to sterilize space capsules

  26. Ethylene Oxide Video • http://www.youtube.com/watch?v=-ICBQg9tcT8

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