Tonsillitis is a common disease of childhood and adolescence. The diagnosis of tonsillitis generally requires the consideration of Group A beta-hemolytic Streptococcus (GABHS) infection. However, numerous other bacteria alone or in combinations, viruses and other infections and non-infectious causes should be considered. Recognition of the cause and choice of appropriate therapy are of utmost importance in assuring rapid recovery and preventing complications.

Penicillin is currently the first-choice treatment for GABHS pharyngotonsillitis. However, the growing failure of penicillin to eradicate GABHS is of concern. This website discusses the potential causes of penicillin failure ( i.e. the presence of beta-lactamse producing bacteria that can “protect” GABHS from penicillins) and methods to overcome them. It also discusses the role of anaerobic bacteria in tonsillitis and its complications.


Thursday, March 1, 2012

Methicillin Resistant Staphylococcus aureus is isolated in greater frequency in tonsillitis


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.


Saturday, February 18, 2012

Why does penicillin not work in Group A streptococcal tonsillitis?


Despite its excellent efficacy in the test tube, penicillin frequently does not work and fail to eradicate Group A beta-hemolytic streptococci (GABHS) from patients with acute and relapsing pharyngo-tonsillitis (PT) is cause for concern.  Over the past 50 years, the rate of penicillin failure has consistently increased from about 7% in 1950 to almost 40% in 2000.






Various explanations exist for the failure of penicillin to eradicate GABHS PT (see page).  One possibility is the poor penetration of penicillin into the tonsillar tissues as well as into the epithelial cells. Other explanations relate to the bacterial interactions between GABHS and other members of the pharyngo-tonsillar bacterial flora.  For example, it is hypothesized that beta-lactamase secreted by beta-lactamase-producing bacteria (BLPB), which colonize the pharynx and tonsils, may “shield” GABHS from penicillins. Another possibility is the coaggregation between Moraxella catarrhalis and GABHS, which can facilitate colonization by GABHS. Normal bacterial flora can interfere with the growth of GABHS, and the absence of such competitive bacteria makes it easier for GABHS to colonize and invade the pharyngo-tonsillar area.






Beta-lactamase producing organisms "protecting" penicillin susceptible bacteria from penicillin

Therapeutic strategies that allow overcoming the above mechanisms are available and are based on extensive clinical research. This website describes the research and therapeutic option for patients who fail penicillin therapy.  





Streptococcal tonsillitis