Friday, November 11, 2011

Superbugs that commonly cause HAIs (2)

Clinically important superbugs that commonly cause healthcare-associated infections include methicillin resistant Staph aureus (MRSA), vancomycin-resistant enterococci (VRE), and multidrug-resistant Gram-negative rods, including strains of Pseudomonas aeruginosa and E. coli. Antimicrobial resistance among nosocomial pathogens often results in prolonged periods of antimicrobial therapy and increased treatment costs, prolonged hospital stays and higher mortality (Dohmen, 2008).

Gram-positive organisms:
Two health care-related pathogens continue to be of particular concern: MRSA and vancomycin-resistant enterococci (VRE). In some hospitals, over 70% of the Staph aureus isolated from inpatients are MRSA (Hu et al., 2009).
1. Staphylococcus aureus:
Since the introduction of penicillin in the late 1940s and throughout the antibiotic era to the present, S.aureus has adapted rapidly by becoming resistant to each new type of drug (Swartz, 1994).
By the late 1960s, more than 80% of both community- and hospital-acquired staphylococcal isolates were resistant to penicillin. This pattern of resistance, first emerging in hospitals and then spreading to the community, is now well established pattern that recurs with each new wave of antimicrobial resistance (Chambers, 2001).
Methicillin, the prototype penicillinase-resistant penicillin, became available in 1959 to treat staphylococci resistant to penicillin. Methicillin is one of several semisynthetic penicillins with bulky side chains, such that the antibiotic undergoes very slow hydrolysis by the staphylococcal beta-lactamase (Jevons et al., 1963).
Methicillin resistant strains of S. aureus were first detected in 1961 in a British hospital, shortly after the introduction of methicillin into clinical use in 1959. MRSA became a major problem in hospital settings worldwide in the 1980s (Boyce, 1994).

Need to read more
read Manual of Antibiotics: Method of Actions, Mechanisms of Resistance and Relations to Health Care associated Infections

If you buy the first book, you can ask for the second part free (Pseudomonas spp., mechanisms of resistnce)

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