An increase in the recovery of methicillin resistant S. aureus (MRSA) was recently noted in various infections. The rate of recovery MRSA in tonsils that were removed because of recurrent Group A -b-hemolytic streptococci (GABHS) tonsillitis was not previously reported. A recent study by Brook & Foote demonstrated for the first time the recovery of MRSA from 16% of the tonsils removed from 44 children because of recurrent GABHS tonsillitis.
The emergence of MRSA in the tonsillar flora in children with recurrent GABHS tonsillitis may contribute to the difficulty in eradicating GABHS with penicillins and other antimicrobials that are ineffective against this organism. MRSA are generally resistant to beta-lactam antimicrobials ( i.e. penicillins) and generally susceptible to clindamycin, trimethoprim-sulfamethoxazole, and vancomycin. The MRSA present in the tonsills may serve as a potential source for the spread of these organisms to other body sites as well to other individuals.
Since most of the MRSA ( 5 of 7 isolated in the study) were also beta-lactamase producers their presence could potentially interfere with the eradication of GABHS by penicillin. MRSA that is also able to produce beta-lactamase can survive treatment with beta-lactam antibiotics and continue to “shield” GABHS from penicillins through the production of the enzyme beta-lactamase. Most of the S. aureus isolated from the tonsilar cores of our patients ( 19 of 26 or 73% ) were, however, beta-lactamase producers and not MRSA. These organisms are susceptible to beta-lactamase resistant penicillins as well as most cephalosporins.
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