Chronic suppurative otitis media remains a global burden for children despite the declining incidence in industrialized countries and advances in diagnosis and management in developing countries. The World Health Organization cites chronic suppurative otitis media (CSOM) as a major cause of acquired hearing loss, primarily in developing countries and indigenous peoples.
CSOM is characterized by a persistent discharge from the middle ear lasting for a minimum of 2 weeks. In industrialized countries, the major risk factor is tympanostomy tube placement; in developing nations, the major risk factor is early bacterial colonization with Streptococcus pneumoniae and nontypable Haemophilus influenzae and early onset of acute bacterial otitis media with perforation. In both situations, biofilms are thought to underlie the pathogenesis with S. pneumoniae and nontypable H. influenzae found on mucosal biopsies using specific fluorescent in situ hybridization assays on specimens from children with chronic suppurative otitis media or recurrent acute otitis media (ROM). Dr. Ruth B. Thornton and her colleagues reported that 11 of 17 (65%) middle-ear mucosal biopsies from children with CSOM or ROM showed evidence of bacterial biofilm, and 12 (71%) demonstrated intracellular bacteria (Pediatrics 2011;11:94).
Dr. Stephen I. Pelton
Microbiologic studies in children with otorrhea, through either a perforation or tympanostomy tube, demonstrate primarily Staphylococcus aureus, both methicillin sensitive and resistant isolates, and Pseudomonas aeruginosa. However, it is recognized that the early pathogens are S. pneumoniae and nontypable H. influenzae in these children recovered both from cultures of ear drainage and from molecular studies of middle-ear mucosal biopsies. Amanda J. Leach, Ph.D., and Peter S. Morris, Ph.D., reported that cultures from ear discharge in Aborigine children with acute perforations identified nontypable H. influenzae in 57%, S. pneumoniae in 34%, and both in 21% (Pediatr. Inf. Dis. J. 2007;26:S4-7).
The high rate of mixed infection has also been reported in Bedouin children with recurrent and persistent otitis. In children with otorrhea from a tympanostomy tube, a dichotomy in microbiology etiology was found. In young children, nasopharyngeal pathogens (S. pneumoniae and nontypable H. influenzae) dominated and in older children, external ear commensals (Staph. aureus and P. aeruginosa) predominated (Int. J. Pediatr. Otorhinolaryngol. 2003;67:1317-23).
In industrialized countries, successful treatment of young children with otorrhea through a tympanostomy tube has been reported with both oral amoxicillin/clavulanate and topical fluoroquinolones, reflecting the frequent role of S. pneumoniae and nontypable H. influenzae in young children. However, in older children, in those with foul-smelling discharge, and in those who fail amoxicillin/clavulanate, topical fluoroquinolone is the treatment of choice. Guidelines for the treatment of otorrhea through a tympanostomy tube have been published with a recommendation that topical therapy be used as the first choice when systemic signs of illness are not present (J. Otolaryngol. 2005;34[suppl. 2]:S60-3). Treatment failures are most often due to methicillin-resistant Staph. aureus (MRSA) and often require a combination of oral therapy with an agent active against MRSA such as trimethoprim/sulfamethoxazole and topical therapy with a fluoroquinolone; removal of the tympanostomy tube also may be necessary to achieve a cure.
The prevention of chronic suppurative otitis media has proven elusive. Studies of 7-valent pneumococcal conjugate (PCV7) vaccine in Dutch children with established ROM demonstrated no reduction in episodes. In fact, more episodes of AOM or otorrhea were observed in the vaccine group, despite good immunogenicity and a reduction in colonization with vaccine-type S. pneumoniae (Int. J. Pediatr. Otorhinolaryngol. 2006;70:275-85).
In studies of PCV7 administered at 2, 4, and 6 months of age to Aborigine infants, only a marginal benefit was observed when they were compared with a historical birth cohort. By 12 months of age, 89% of those vaccinated had experienced AOM; 34%, AOM with perforation; and 14%, CSOM. Although not statistically significant, this represented a 40% decrease in CSOM at 1 year of age (BMC Pediatr. 2009;9:14).
CSOM persists as an important cause of morbidity in indigenous children and in children in developing countries. It is a major cause of acquired hearing loss and impacts dramatically on the quality of life of affected children. We have made important advances in identifying the bacterial antecedents and understanding the pathogenesis of disease, yet morbidity remains substantial. Further research in the treatment and prevention of middle-ear biofilms is likely to be critical to reducing the burden of ear disease in children.
Dr. Pelton is chief of pediatric infectious disease and also is the coordinator of the maternal-child HIV program at Boston Medical Center. He disclosed that he has received honoraria and investigator-initiated research funding from Pfizer and Merck, and honoraria from GlaxoSmithKline related to pneumococcal vaccines. E-mail him at pdnews@elsevier.com.