Enhanced effects of amoxycillin/clavulanic acid compared with amoxycillin and clavulanic acid alone on the susceptibility to immunodefenses of a penicillin-resistant strain of Streptococcus pneumoniae
Am. Cuffini et al., Enhanced effects of amoxycillin/clavulanic acid compared with amoxycillin and clavulanic acid alone on the susceptibility to immunodefenses of a penicillin-resistant strain of Streptococcus pneumoniae, DRUG EXP CL, 24(4), 1998, pp. 173-184
The recent increase in the incidence of infections due to Streptococcus pne
umoniae resistant to penicillin and other antibiotics, often associated wit
h considerable morbidity and mortality has been recognized as an alarming p
roblem. From the recent medical literature data it emerges that among beta-
lactam antibiotics used as an empiric treatment for infections caused by S.
pneumoniae, amoxycillin and amoxycillin/clavulanic acid are the most activ
e oral antibiotics and may be considered as a first-line therapeutic agent
for the treatment of these infections. Since the therapeutic result of the
treatment of an infection is determined by the combined effect of the antim
icrobials and host defenses, we investigated the effect of amoxycillin, wit
h and without clavulanic acid, upon the in vitro interaction between human
polymorphonuclear leukocytes (PMNs) and a penicillin-resistant strain of S,
pneumoniae. Amoxycillin significantly inhibited the streptococcal uptake b
y PMNs referred to the control system. Clavulanic acid did not have any sig
nificant effect upon the interaction PMNs-S. pneumoniae. The addition of am
oxycillin/clavulanic acid to phagocytes and streptococci resulted in a syne
rgystic potentiation of the activity of both drugs upon the PMN functions t
owards S. pneumoniae in such a manner that the bacteria became more suscept
ible to either the phagocytosis or the microbicidal activities of phagocyte
s. These effects came in addition to the intrinsic, excellent antimicrobial
properties of this drug combination. Although the clinical significance of
the observed enhanced effects of amoxycillin/clavulanate are far from eluc
idated, the possibility exists that they may play a contributory role, espe
cially in patients with impaired host defense.