Micro lecture 26 Notes Chapter 26 Infections of the Body's Surfaces p. 688-712

Chickenpox vs. Herpes Zoster (shingles).

The skin; often imitated, never duplicated ; an underappreciated, essential barrier.

The cornea; transplants, glaucoma, cataract removal by Egyptians? New advance; artificial lens!

Impetigo; crowded kids are a "transmission waiting to happen." Accentuate dryness, intervene early to prevent, control. Triple antibiotic ointments; toxic internally, O.K. on skin.

Virulence factors: Hyaluronidase, leukocidins, streptokinase, haemolysins (streptolysins), coagulase. Diabolical agents, utterly without redeeming value?

Staphylococcus aureus: causative agent of the most U.S. infections. "Golden staph" dreaded until antibiotic era; reason people went to the hospital, "to die".

Penicillinase, other drug-resistance factors of great concern ( Vancomycin-resistance increasing greatly. Teicoplanin as cost-effective as Vancomycin, fewer side effects. Resist one= resist other).

Pseudomonas aeruginosa; versatile, promiscuous, problem. Cystic fibrosis lung clearing problem. Nosocomial infections (10-20%).

Bacteriolytic + bacteriostatic simultaneous antibiotic use?

Clostridium perfringens and "gas gangrene". Hyperbaric O₂ of questionable value. Amputate early, amputate often! Vietnam wound: an unnecessary case?

Antibiotics for acne: resistance inevitable. Long-term scarring, versus teratogenic effects of Acutane.

Leprosy. Long an incurable scourge. Value of pain. "Unclean, unclean..." weakly transmissible.

Chickenpox (vaccinate), shingles. "Don't get old!" Measles: devastating in Hawaii, American Indians. Highly contagious. German measles: congenital problems.

Smallpox: eradicated in 1977? Iraq, others may have samples. Last time in Germany, spread to many vaccinated individuals, several of which died.

Fungi, arthropod-caused, eye infections: see text. "Absolutely astonishing" worth reading. Hypnosis removes warts from ½ of body. (Better than distilled water!)

Onchocerciasis: Carter Center("best ex-president"), Monsanto Corporation: provided $2 drug free; major humanitarian efforts.

http://www.mja.com.au/public/issues/171_3_020899/robertsn/robertsn.html

Introduction The emergence of resistant strains of Staphylococcus aureus and coagulase-negative staphylococci has resulted in increased use of the glycopeptide antibiotics vancomycin and teicoplanin.1 These antibiotics are the only effective treatments for infections with these pathogens, but the emergence of vancomycin-resistant enterococci (VRE) threatens their utility. ^1,2 VRE can cause serious life-threatening infections, and can transfer their resistance in vitro to other pathogens, such as Staphylococcus, rendering the bacteria resistant to currently available antimicrobials.^3,4 The emergence of VRE has been linked to both overuse and inappropriate use of antibiotics such as vancomycin, teicoplanin and extended-spectrum cephalosporins.^2,4 There is also a strong relationship with the use of glycopeptide antibiotics in animals.⁵ Australian studies have reported inappropriate use of vancomycin ranging from 42% to 65% in individual hospitals. ^6,7 Responding to these concerns, consensus guidelines have been disseminated to all Victorian hospitals. ⁸ The aim of this study was to examine patterns of prescribing vancomycin and teicoplanin in Victorian hospitals in order to identify potential areas for targeted intervention to improve use of these antibiotics.

http://www.anaesthetist.com/icu/manage/drugs/infect/teico.htm

Dose: Usually 6mg/kg/day, after two loading doses 12hr apart (each 6mg/kg)

Many Gram-positive bacteria that were sensitive to simple penicillins are now resistant. In the past, the best treatment for these nasty bacteria was vancomycin, which unfortunately has significant side effects. Teicoplanin is a less toxic replacement for vancomycin in most situations where resistant organisms are encountered. In several clinical circumstances, empiric treatment with teicoplanin is extremely effective. The best established of these circumstances is neutropaenic sepsis. Carefully selected patients may also benefit from teicoplanin prophylaxis.

In appropriate doses, teicoplanin is usually as cost-effective as vancomycin, with less toxicity.

In a few special circumstances, vancomycin may still be the drug of choice, despite its extra toxicity. The looming spectre of vancomycin (and/or teicoplanin) resistance should encourage us to be careful and not use either drug recklessly.

When to use it: Sensitive organisms Teicoplanin is mainly used in moderate to severe infections with Gram-positive organisms. It is not effective against Gram-negatives. It is important to remember that in Gram-positive infections that are known to be sensitive to simples agent such as penicillin or cloxacillin, these are the drugs of choice. As is always the case, the correct drug should be given for the correct duration, to minimise resistance.

The following microorganisms are usually or frequently sensitive to teicoplanin:

Staphyloccus aureus Staphylococcus epidermidis Streptococci Enterococci (although resistance is now emerging!) Clostridium species including Clostridium difficile Peptostreptococci Other less frequent pathogens such as Corynebacteria, and Propionibacterium. There is a small number of organisms that are inherently resistant to teicoplanin. These are usually not pathogenic, or not often encountered, but include: Erysipelothrix Leuconostoc, Pediococcus and some Lactobacilli.

Far more important is acquired resistance. This has recently emerged as a substantial problem in Enterocci. Organisms that are resistant to teicoplanin are also often resistant to Vancomycin, and vice versa. Some organisms may be sensitive to teicoplanin, and resistant to vancomycin, or the reverse may occur. If vancomycin and teicoplanin resistance is present, then there may be no effective treatment for the patient, apart from some experimental agents that are not yet readily available.