Is recurrent tonsillitis in adults different from one in children?

 Brook and Foote compared the microbial flora of recurrently inflamed tonsils removed from 25 children with recurrent episodes of tonsillo-pharyngitis were compared to flora of tonsils removed from 23 adults suffering from similar illness. More bacterial isolates in each tonsil were found in adults (10.2 per tonsil) than in children (8.4 per tonsil). The difference between these groups was due to a higher recovery rate in adults of anaerobic Gram-negative bacilli. Conversely, Group A beta-hemolytic streptococci were isolated in seven (28%) children as compared to their isolation in only one (4%) adult.

More isolates of beta-lactamase-producing organisms (BLPO) per tonsil were recovered in adults. Forty-three BLPO were detected in 21 (91%) of the 23 tonsils removed from adults as compared to only 16 (64%) of the children (1.2 isolates per patient) (P=0.04).

These findings suggest that the cause of recurrent tonsillitis in adults may differ from that in children. The differences in the tonsillar microbiology may be due to the effect of many more courses of antimicrobials given over the years to adults and the changes in tonsillar tissue that occur in this age group.

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.

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