Spectrum of bactericidal action of amylmetacresol/2,4-dichlorobenzyl alcohol lozenges against oropharyngeal organisms implicated in pharyngitis

Abstract

PurposePharyngitis is commonly caused by a self-limiting upper respiratory tract infection (URTI) and symptoms typically include sore throat. Antibiotics are often inappropriately used for the treatment of pharyngitis, which can contribute to antimicrobial resistance, therefore non-antibiotic treatments which have broad antiseptic effects may be more appropriate. Amylmetacresol (AMC) and 2,4-dichlorobenzyl alcohol (DCBA) are present in some antiseptic lozenges and have established benefits in providing symptomatic relief and some in vitro antiviral action.MethodsSeven bacterial species associated with pharyngitis, namely Streptococcus pyogenes, Fusobacterium necrophorum, Streptococcus dysgalactiae subspecies equisimilis, Moraxella catarrhalis, Haemophilus influenza, Arcanobacterium haemolyticum and Staphylococcus aureus, were exposed to an AMC/DCBA lozenge dissolved in artificial saliva. In vitro bactericidal activity was measured as a log reduction in colony-forming units (CFUs).ResultsBactericidal activity was recorded against all organisms after 1 minute. Greater than 3 log10 reductions in CFUs were observed at 1 minute for S. pyogenes (log10 reduction CFU/mL ± SD, 5.7±0.1), H. influenza (6.1±0.1), A. haemolyticum (6.5±0.0) and F. necrophorum (6.5±0.0), at 5 minutes for S. dysgalactiae (6.3±0.0) and M. catarrhalis (5.0±0.9) and at 10 minutes for S. aureus (3.5±0.1).ConclusionAn AMC/DCBA lozenge demonstrated a greater than 99.9% reduction in CFUs against all tested species within 10 minutes, which is consistent with the time a lozenge remains in the mouth. Patients with uncomplicated bacterial pharyngitis may benefit from the antibacterial action of antiseptic AMC/DCBA lozenges. Furthermore, AMC/DCBA lozenges may be more relevant and appropriate than antibiotics for pharyngitis associated with a self-limiting viral URTI.

Bactericidal activity of hexylresorcinol lozenges against oropharyngeal organisms associated with acute sore throat

“…In a similar in vitro study, Matthews et al (2018) reported that lozenges containing 0.6 mg amylmetacresol and 1.2 mg 2,4-dichlorobenzyl alcohol had broad antibacterial activity against a similar range of oropharyngeal organisms associated with acute sore throat. Specifically, reductions in bacterial counts exceeded 99.9% by 1 min for S. pyogenes, H. influenzae, F. necrophorum and A. haemolyticum, by 5 min for M. catarrhalis and S. dysgalactiae and by 10 min for S. aureus [21]. The antibacterial effects of hexylresorcinol lozenges reported here add to existing knowledge of their activity, which include numbing effects [13,14] and antiviral activity [16,17], resulting in relief of sore throat symptoms [13].…”

“…Hexylresorcinol 2.4 mg lozenges (Strepsils Extra Honey and Lemon lozenges; Reckitt Benckiser, Slough, UK) were dissolved at 44 ± 1 ℃ into 5 mL of artificial saliva medium as described previously [21].…”

“…S. aureus (NCTC7445, Public Health England, Salisbury, UK), S. pyogenes (NCTC12696, Public Health England), M. catarrhalis (NCTC3622, Public Health England), H. influenzae (NCTC4842, Public Health England) and F. necrophorum (NCTC12238, Public Health England) were cultured as described previously [21].…”

“…The bactericidal assay was performed using a method similar to that described previously [21]. Briefly, inoculum suspensions prepared in triplicate for each test organism, at approximately 10 8 colony-forming units (cfu)/mL in saline, were mixed with hexylresorcinol test sample (4.9 mL).…”

Modern chemical disinfectants and antiseptics. Part II

“…2,4-Дихлорбензиловий спирт (13) (рис. 4) інколи додають як бактерицидний засіб до зубних паст та пастилок для лікування фарингіту [96].…”