A prospective study of seven patients with chronic mastoiditis

Abstract

Introduction: Chronic mastoiditis is generally a result of chronic suppurative otitis media; it is rarely a result of failure of treatment of acute mastoiditis. Case presentation: Seven patients with chronic mastoiditis were investigated. Four patients had bilateral mastoiditis. The duration of illness ranged from 1 to 45 years. A comparison between operative and external auditory canal cultures was performed. The operative specimens were obtained directly from the infected mastoids. The external ear and mastoid specimens were inoculated and cultivated immediately by bedside. All cases showed positive bacterial cultures. The growth was monomicrobial in two cases and polymicrobial in five cases. Seventeen isolates were recovered (11 aerobes and six anaerobes). Pseudomonas aeruginosa was the most predominant isolate (23.5 %) and was recovered from four patients (57 %). This high prevalence may be related to misuse of ear drops that transmit this organism from skin flora towards the mastoid. The anaerobes were isolated from four patients. This may indicate a significant role of anaerobic bacteria in producing chronic mastoiditis that would not respond to usual treatment measures. Conclusion: Cultures from external ear canal discharge might be used as a source for isolation of bacteria causing chronic mastoiditis and chronic otitis media provided that the specimen was collected and cultivated properly. They revealed sensitivity (88 %), specificity (100 %), positive predictive value (100 %) and negative predictive value (66 %). In anaerobic cultures, the sensitivity was 66.7 %. No previous studies were found with regard to evaluation of the reliability of external ear culture for isolation of the causative agents of chronic mastoiditis or chronic otitis media.

Microbial study of pre and postoperative mastoid cavities: a comparative study

“…[9][10][11] In yet another study by Mousa, Pseudomonas was the most common organism isolated (23.5% of cases) followed by, which was followed by Proteus spp, coagulase-negative Staphylococci, and Prevotela melaninogenica. 12 The high prevalence was attributed to the improper use of antibiotic ear drops that transmit this organism from skin into middle ear and mastoid. Moreover, Pseudomonas was resistant to most of the antibiotics.…”

“…Moreover, Pseudomonas was resistant to most of the antibiotics. 12 A study by Verhoeff et al reported the most common organism to cause CSOM was Pseudomonas and this organism was particularly implicated in in the causation of bony necrosis and mucosal disease. 13 Another study involving CSOM also considers Pseudomonas to me the most common causative organism.…”