Abstract:
Background: Prevalence of bacterial ear infections is moderately high in developing countries
like Sri Lanka. Absence of human cerumen is known to predispose to ear infections.
Objectives: To investigate in-vitro antibacterial properties of human cerumen.
Methodology: A cross sectional study involving individuals of all age groups attending the ear,
nose and throat clinic at National Hospital of Sri Lanka was conducted. Patients with middle or
external ear pathology were excluded. Hundred cerumen specimens were collected to study the
antibacterial activity using spread plate count method. Cerumen suspensions of 3.5% were
prepared aseptically and inoculated on nutrient agar and incubated at 37 0C for 24 hours. Any
microbial growth was noted. The cultures which did not show any growth on nutrient agar were
considered as sterile and they were subjected to further examination. Freshly isolated control
bacterial strains; Staphylococcus aureus ATCC 25923, Eschereria coli ATCC 25922 and
Pseudomonas aeruginosa ATCC 27853 were used to make inoculums in nutrient broths. One in
ten dilutions of 3.5% cerumen preparations were inoculated in blood agar plates and incubated
at 37 0C for 24 hours. Sterile cerumen samples were further examined with E. coli, P.
aeruginosa and S. aureus. Antibacterial properties of human cerumen were qualitatively
assessed by comparing the growth of bacteria in the cerumen suspension against control
samples. All data were analyzed using descriptive statistics using SPSS.
Results: Of 100 cerumen specimens tested 44 (44.0%) specimens were sterile. Sterile cerumen
samples showed antibacterial activity against E. coli, P. aeruginosa and S. aureus; 93%, 89%
and 66%, respectively.
Conclusions: Human cerumen possesses antibacterial activity against Staphylococcus aureus,
Pseudomonas aeruginosa and Escherichia coli.
