Colonization, safety, and tolerability study of the Streptococcus salivarius 24SMBc nasal spray for its application in upper respiratory tract infections.

Streptococcus salivarius, a non-pathogenic species and the predominant colonizer of the oral microbiota, finds a wide application in the prevention of upper respiratory tract infections, also reducing the frequency of their main pathogens. In this pilot study, the primary objective was to evaluate the safety and tolerability of a nasal spray, S. salivarius 24SMBc, as a medical device in a clinical study involving 20 healthy adult subjects. The secondary aim was to determine the ability of colonization assessed by molecular fingerprinting. Twenty healthy adult subjects, aged between 30 and 54 years, without a medical history of recurrent otitis media, were enrolled. All patient characteristics fulfilled the inclusion criteria. All subjects were treated daily for 3 days with the nasal spray containing S. salivarius 24SMBc at a concentration of 5 × 10(9) colony-forming units (CFU)/ml. The persistence of S. salivarius in the nasopharynx was investigated by the antagonism test and random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). The tolerability and safety were clinically assessed by clinical examinations during treatment. Our results demonstrate the capability of S. salivarius 24SMBc to colonize the rhinopharynx tissues in 95% of subjects and persist in 55% of them after 6 days from the last dose of the formulation, maintaining a concentration of 10(5) CFU/ml. The treatment was well tolerated by all healthy patients and no adverse effects were found. The topical application of streptococcal probiotics is a relatively undeveloped field but is becoming an attractive approach for both prevention and therapy, especially for pediatric age patients. S. salivarius 24SMBc possess characteristics making this strain suitable for use in bacteriotherapy.

Streptococcus salivarius 24SMB administered by nasal spray for the prevention of acute otitis media in otitis-prone children.

This paper reports the results of the first study in which Streptococcus salivarius 24SMB, a safe α-haemolytic strain capable of producing bacteriocin-like substances with significant activity against acute otitis media (AOM) pathogens, was intranasally administered in an attempt to reduce the risk of new episodes of AOM in otitis-prone children. In this prospective, randomized, double-blind, placebo-controlled study, 100 children aged 1-5 years with histories of recurrent AOM were randomized 1:1 to receive an intranasal S. salivarius 24SMB or placebo twice daily for 5 days each month for 3 consecutive months. Fifty treated children and 47 who received placebo who were compliant with study protocol were followed monthly for 6 months. The number of children who did not experience any AOM was higher among the children treated with the S. salivarius 24SMB preparation than among those in the placebo group (30.0 vs 14.9%; p = 0.076). Moreover, the number of children who received antibiotics during the study period was lower among the children treated with S. salivarius 24 SMB than among those who received placebo (70 vs 83.0%; p = 0.13). Compared with the children who were not colonized by S. salivarius 24SMB after treatment, the number of colonized children who experienced any AOM was significantly lower (42.8 vs 13.6%; p = 0.03). Similar results were observed when the children treated with antibiotics for AOM were analysed (67.8 vs 95.5%; p = 0.029). This study revealed the ability of intranasally administered S. salivarius 24SMB to reduce the risk of AOM in otitis-prone children.