Out line 1.Introduction. 2.Definitions. 3.Resistance. 4.Basic principles of antimicrobial use. 5.Monitoring bacterial resistance and antibiotic usage. 6.Combination antimicrobial therapy. 7.Conclusion.
Introduction In the past the production of antimicrobials gave us an advantage in our struggle against micro-organisms. Now the increase of antimicrobial resistance is now decreasing our ability to control the spread of infectious diseases.
Introduction The misuse of antimicrobial agents has been observed in many countries around the world, resulting in the development of multiple resistant pathogens and the emergence of multidrug- resistant bacterial m.o. “super- bugs”.
Introduction The occurrence of super-bugs is associated with : -treatment failure, higher morbidity and mortality; -An increased length of hospital stay. -Increased cost of healthcare. -And constitutes a major risk for human health
Introduction As the literature shows Antimicrobial resistance is multifactorial : In all known cases, the introduction of new antimicrobial compounds resulted in the emergence of resistance In all known cases, the introduction of new antimicrobial compounds resulted in the emergence of resistance. Misuse of antibiotic by the physicians: –Administering antibiotics for viral infections –Prescribing wrong antibiotics The link between antimicrobial consumption and the emergence of bacterial resistance is now clearly established in hospital settings.
Definitions Antimicrobial medications: medications that inhibit the growth of or kill microorganisms such as bacteria, fungi, viruses, protozoa. Resistance: the ability of microorganisms to counteract the bacteriostatic or bactericidal effects of an antimicrobial agent.
Resistance How do m.o.develop resistance? m.o. develop resistance by: 1.Enzymes: m.o produce various enzymes to inactive antimicrobial agents. e.g. B-lactamase inactive penicillins and cephalosporines. 2.Decreased cellular penetration: m.o. alter their cell wall permeability to prevent penetration of antimicrobial agents into the cell. e.g. pseudomonas- ceftazidime.
How do m.o.develop resistance? 3.Altered target proteins: m.o. change target proteins so that antimicrobial agents cannot bind and elicit antimicrobial activity,(e.g streptococcus pneumonia resistance to penicillin). 4.Efflux pump : m.o. pump antimicrobial agents out of the cell before the antimicrobial agent can kill the m.o. (e.g. S.pneumonia resistance to erythromycin).
Basic principles of antimicrobial use 1.Antibiotics must reach the target tissue in a concentration adequate to inhibit the growth of or to kill the desired m.o. 2.The choice of antimicrobial agents must take into account: a. m.o. susceptibility to available antimicrobial agents. b. relative permeability of the target tissue to agent of choice (e.g. blood brain barrier).
c. Bioactivity of chosen antimicrobial agent in target tissue (bactericidal or bacteriostatic). d. Specific characteristics of the individual patient in relation to the chosen antimicrobial's toxicities (e.g. the blood levels of a nephrotoxic antimicrobial such as gentamicin should be closely monitored in patients with impaired renal function).
Monitoring bacterial resistance and antibiotic usage. A good program for the prevention of resistance must include an active system for the surveillance of antimicrobial resistance and antibiotic usage. No specific action can be developed if antimicrobial resistance and antibiotic consumption are not monitored properly.
Monitoring bacterial resistance and antibiotic usage Microbiology laboratories must provide antimicrobial susceptibility data to guide clinicians’ choices in antibiotic treatment and to aid in the prudent use of antibiotics.
The reporting of antimicrobial resistance data is necessary to determine the optimal empirical antimicrobial therapy according to local resistance patterns, and to fight against the emergence of antimicrobial resistance.
Combination antimicrobial therapy According to literature, I t has been reported previously, that the emergence of resistance is less common when combination therapy is used. Recently No significant advantage was found with combination therapy regarding the development of antimicrobial resistance, but this is controversary,as in some particular situations CAT may be warranted (e.g. treatment of pseudomonas aeruginosa and enterobacter aerogenes infections. The emergence of resistance during single-drug therapy has been documented, especially with third-generation cephalosporin for the treatment of enterobacter infection.
conclusion Many aspects of interventions seem to lead to the best results in the fight against antimicrobial resistance. Actions should be determined and prioritized. The development of an effective system for the surveillance of antimicrobial use and anti microbial resistance is mandatory. Appropriate infection control measures should also be reinforced to control the cross- transmission of resistant microorganisms.
Educational programmes and practice guidelines have a positive impact in terms of the appropriateness of antimicrobial treatment. Continuous efforts are needed to maintain educational programmes, hygiene, antibiotic policies and surveillance system to control antimicrobial resistance.