Disinfectants and Microbials

Chemical means of controlling growth ● ● ● ● ● ● ● ● ● ● ● hand soap: surface active agents - mechanically removes the micro-organisms phenols – good disinfectants, ○ remain active in presence of organic material ○ e.g. ®Lysol ○ Irritating to skin ○ Disrupts lipids in membranes causing cell death bisphenol- antiseptic e.g. ®Phisohex ○ Good for gram positices biguanides – antiseptic e.g. ®Chlorhexidine ○ Most vegetative (active) bacteria and fungi quaternary ammonium compounds: ®Cepacol (mouthwash) ○ Derivative of ammonium that has a funicidal, amoebacidal, bactericidal (for gram positives), and viralcidal for enveloped viruses ○ Inactivated by organic compounds alcohols – isopropyl/ethanol ○ Isproponal is more effective because evaporates slowly so more contact time ○ 70% ethanol is effective because water is still needed to denature proteins and disrupt the cell membrane ○ Not for cleaning wounds because it causes protein coagulation and may result in bacterial growth in scabs ○ SKIN DEGERMING heavy metals- silver, mercury ○ Act as inhibitors for enzymes halogens – chlorine, iodine (can sterilize if used well) ○ Chlorine is a strong oxidizing agent (Chlorox) ○ Iodine can be mixed with alcohol to form tincture or iodaphor if mixed with organic sybstance for more controlled release in the body ○ SKIN DISINFECTANT Aldehydes: sterilize! (e.g. glutaraldehyde or ®Cidex) ○ For instruments and materials that can’t be autoclaved. ○ Inactivates endospores and denature proteins ethylene oxide: gas that sterilizes ○ VERY strong and only used in industries ○ In closed chambers ○ Toxic ○ Can inactivate endospores peroxygens: strong oxidizer, sterilizes if enough contact time ○ Peracetic acid - most useful ○ Hydrogen peroxides and ozones Antibiotics Nucleic Acid Synthesis ● Folate synthesis ○ Sulfonamides ○ Trimethoprim ● DNA Gyrase ○ Quinolones(Cyprofloxacin) ● RNA Polymerase ○ Rifampin (or Rifampicin) ○ Protein Synthesis ● ● ● ● Cell Wall Synthesis ● Beta Lactams ○ Penicillins ○ Cephalosporins ○ Carbapenems ○ Monobactams ● Vancomycin ● Bacitracin Cell Membrane ○ Polymyxins (topical) 50s ○ Macrolides ○ Clindamycin ○ Linezolid ○ Chloramphenicol 30s ○ Tetracyclines ○ Aminoglycosides (Gentamicin) Antimicrobial side effects ● ● ● ● ● Kidney - aminoglycosides Liver - fluoroquinolones Rash, allergy - penicillins Gl upsets - penicillins Nerve damage - fluoroquinolones ● ● ● Ototoxicity - aminoglycosides Teeth and bone formation in children - tetracyclines Cartilage formation in children - fluoroquinolones RANDOM NOTES ● Resistance ○ Result of overuse, improper treatment, and not finishing prescription ○ Bacterial inhibition be done by: ■ Destruction of drug ■ Alteration of target site ■ Ejection of drug ■ Prevent penetration ○ Natural - penicillin F,V,G ○ Semi-synthetic - Methicilin, oxacilin, carbenicilin, ampicilin (active portion of antibiotic is protected from enzymes) ■ Staphylococci aureus mutated again → MRSA to change its binding site from PBP2 to PBP2a which has a low affinity for penicillin.Vancomycin used. Then, a strain ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ that’s VRSA appeared!! ■ Vancomycin resistant entercocci VRE - after using avoparcin glycopeptide in animal feed which has similar structure to vancomycin from multiple genetic mutations in genes Van A, Van B, and Van C ■ ESBL - extended spectrum beta-lactamase has many resistance genes in enterbacteriaceae. Often in ICU and extended care. Resistant to penicillins and cephalosporins and meropenem (good betalactam) ■ XDR-TB - resistant to first and second line of anti TB drugs. Combined drugs of pretomanid and bedaquiline and linezolid for 6 months is curing First synthetic microbial was Sulfa for bacteria. Prokaryotes need to synthesize folic acid, Immunactive substances include interferon which stop the spread of infections, but lots of side effects. Quinine is an anti-protozoa for malaria, but resistance is building up Antifungals associated commonly with kidney and liver problems. Antiviral - entry inhibitors that prevent entrey of virus (fuzeon for HIV) ■ Uncoating inhibitor - M2 proton channel ■ AZT (azidothymidine) and zidovudine for HIV blocks the reverse transcriptase ■ Acyclovir for herpes ■ tamiflue / oseltamivir for exit of influenza A through neuramindase ■ Nucleoside analogues that makes nucleotides non-functional Erythromycin/macrolides are bacteriostatic Streptococcus pneumoniae - G + treated with penicillin G (narrow spectrum) Those who go through chemotherapy which also kills some WBC will be more prone to infections as well as those with neutropenia who lack neutrophiils. MIC - minimum inhibitory concentration that inhibits (not kill) the microorganism to determine the dosing levels and intervals. Determined by Ellipse-test