 Sepsis refers to microbial contamination  Asepsis is the absence of significant contamination Aseptic surgery techniques prevent microbial contamination of wounds  Sterilization: Removing all microbial life

 Disinfection: Removing pathogens from surfaces  Antisepsis: Removing pathogens from living tissues  Sanitization: Lowering microbial counts to acceptable (public health) standards  Biocide/germicide: Kills microbes  Bacteriostasis: Inhibiting, not killing, bacteria

A. the microbe’s characteristics ex. Mycobacterium tuberculosis vs. HIV B. environmental conditions ex. blood present C. concentration of agent ex. 70% alcohol D. time of exposure E. number of microbes to begin with

A. physical removal – ex. soaps B. disruption of p.m. – ex. alcohols C. denaturing proteins – ex. phenols D. damage to DNA – ex. UV light E. damage to many molecules – ex. H 2 O 2

I. Physical Methods of Control: A. Heat 1. dry – oven, 160 o C for several hours 2. moist – autoclave/ pressure cooker 121 o C for 15 minutes at 15 psi 3. pasteurization – 63 o C for 30 min, 72 o C for 15 seconds, ~ 140 o C for 1 second 4. flaming/incineration

B. Cold(?) 1. refrigeration – 4 o C/40 o F ;doesn’t kill; slows down growth 2. freezer – minus 20 o C; ice crystals in cells may kill them

C. Removal of water 1. dessication 2. adding solutes, ex. salts, sugars

D. Filtration HEPA (High Efficiency Particulate Air) filters Membrane filters Used to sterilize things that can’t be heated, etc. Ex. Antibiotics, vaccines, enzymes, some media, vitamins, etc.

Blue colonies grown on agar are fecal coliform bacteria (left). A close-up, colorized view of fecal coliform (right).

E. Radiation 1. Ionizing radiation – X-rays, gamma irradiation 2. Ultraviolet light

F. Soaps and detergents

II. Chemical Methods of Control A. phenol compounds – ex. phenol, Cresol, pHisoHex, Lysol i. Denaturation of proteins ii. Effective against TB

B. chlorhexidine – in hand scrubs i. Hibiclens (brand name) ii. Low toxicity iii. Effective against spores, TB, cysts of parasites, etc.

C. halogens – iodine, bleach, Betadine (with alcohol) Iodines for skin; bleach for surfaces and water

D. alcohols – rubbing alcohol, ethanol i. Work best with some water; ii. 70% concentration most effective iii. Low toxicity

E. heavy metals – mercury, lead, silver, etc. Mercury in vaccines -- thimerosal Lead in paints Silver nitrate for newborn eyes Copper for algae

Ileal-lymphoid-nodular hyperplasia, non-specific colitis, and pervasive developmental disorder in children. Wakefield AJWakefield AJ, Murch SH, Anthony A, Linnell J, Casson DM, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Harvey P, Valentine A, Davies SE, Walker-Smith JA.Murch SHAnthony ALinnell JCasson DMMalik MBerelowitz MDhillon APThomson MAHarvey PValentine ADavies SEWalker-Smith JA Inflammatory Bowel Disease Study Group, University Department of Medicine, Royal Free Hospital and School of Medicine, London, UK. BACKGROUND: We investigated a consecutive series of children with chronic enterocolitis and regressive developmental disorder. METHODS: 12 children (mean age 6 years [range 3-10], 11 boys) were referred to a paediatric gastroenterology unit with a history of normal development followed by loss of acquired skills, including language, together with diarrhoea and abdominal pain. Children underwent gastroenterological, neurological, and developmental assessment and review of developmental records. Ileocolonoscopy and biopsy sampling, magnetic-resonance imaging (MRI), electroencephalography (EEG), and lumbar puncture were done under sedation. Barium follow-through radiography was done where possible. Biochemical, haematological, and immunological profiles were examined. FINDINGS: Onset of behavioural symptoms was associated, by the parents, with measles, mumps, and rubella vaccination in eight of the 12 children, with measles infection in one child, and otitis media in another. All 12 children had intestinal abnormalities, ranging from lymphoid nodular hyperplasia to aphthoid ulceration. Histology showed patchy chronic inflammation in the colon in 11 children and reactive ileal lymphoid hyperplasia in seven, but no granulomas. Behavioural disorders included autism (nine), disintegrative psychosis (one), and possible postviral or vaccinal encephalitis (two). There were no focal neurological abnormalities and MRI and EEG tests were normal. Abnormal laboratory results were significantly raised urinary methylmalonic acid compared with age-matched controls (p=0.003), low haemoglobin in four children, and a low serum IgA in four children. INTERPRETATION: We identified associated gastrointestinal disease and developmental regression in a group of previously normal children, which was generally associated in time with possible environmental triggers. PMID: [PubMed - indexed for MEDLINE]

Retraction of an interpretation. Murch SHMurch SH, Anthony A, Casson DH, Malik M, Berelowitz M, Dhillon AP, Thomson MA, Valentine A, Davies SE, Walker-Smith JA.Anthony ACasson DHMalik MBerelowitz MDhillon APThomson MAValentine ADavies SEWalker-Smith JA Centre for Paediatric Gastronenterology, Royal Free and University College Medical School, Royal Free Campus, London NW3 2PF, UK. PMID:

F. ammonia compounds NH 3 Pseudomonas spp. can GROW in some ammonia compounds

G. preservatives Sulfites in wine and many other foods Nitrates/nitrites in meats

H. aldehydes Formaldehyde – embalming, preservation of specimens Glutaraldehyde – preserving eukaryotic cells

I. gases Ethylene oxide – high toxicity, not wet, even mattresses can be treated

J. peroxides – highly reactive with many molecules Hydrogen peroxide – most effective against anaerobes

The End