Reduction of group A beta-hemolytic streptococcus pharyngo-tonsillar infections associated with use of the oral probiotic Streptococcus salivarius K12: a retrospective observational study

Giuseppe Gregori,1 Ornella Righi,1 Paolo Risso,2 Goffreda Boiardi,1 Giovanni Demuru,1 Anna Ferzetti,1 Antonio Galli,1 Marco Ghisoni,1 Sonia Lenzini,1 Claudio Marenghi,1 Caterina Mura,1 Roberto Sacchetti,1 Lucia Suzzani1 1Primary Care Department, Local Health Unit (ASL), Piacenza, 2Department of Health Science (DISSAL), University of Genoa, Genoa, Italy Abstract: Recurrent pharyngo-tonsillar infections caused by group A beta-hemolytic streptococci (GABHS) occur frequently in young children, and the treatment of these infections contributes substantially to the total current requirement for antibiotic prescribing. Our study goal was to assess through a retrospective observational analysis whether the administration of the oral probiotic, Streptococcus salivarius K12 (SsK12), could reduce the occurrence of GABHS pharyngo-tonsillar infections in children who had a recent history of recurrent episodes of these infections. Twelve primary care pediatricians identified, through their databases, a total of 130 children who had experienced recurrent GABHS pharyngo-tonsillar infections over a period of at least 6–12 months prior to their inclusion in the study. Of these children, 76 then undertook a 90-day program requiring once-a-day dosing with a commercially available (Bactoblis) lozenge containing SsK12. No probiotic supplement was given to the remaining 54 (control) children. Each subject was monitored for the occurrence of GABHS pharyngo-tonsillitis and also for acute otitis media, bronchitis, sinusitis, and bronchopneumonia for at least 12 months following their entry to the study. Even 9 months after the use of SsK12 had been stopped, the probability of new GABHS infections was significantly lower (P>0.001) when compared to the period before dosing commenced. When compared to the untreated children, those taking SsK12 appear to have had significantly fewer GABHS infections both during the 90-day period of prophylaxis and during the following 9 months (P<0.001). These observations are supportive of the use of probiotic SsK12 for the control of recurrent GABHS pharyngo-tonsillar infections in children, and as an associated benefit, the use of this probiotic could lead to reduced antibiotic consumption. Follow-up controlled prospective studies should now be initiated in order to further establish the efficacy of this newly emerging prophylactic strategy. Keywords: recurrent pharyngo-tonsillar infections, group A beta-hemolytic streptococcus, Streptococcus salivarius K1