Article

Changes in frequency and pathogens causing acute otitis media in 1995-2003.

Elmwood Pediatric Group, Department of Pediatrics, University of Rochester, Rochester, NY, USA.
The Pediatric Infectious Disease Journal (Impact Factor: 3.14). 10/2004; 23(9):824-8.
Source: PubMed

ABSTRACT This study was undertaken to determine whether a change in the frequency or distribution of the causative pathogens in persistent acute otitis media (AOM) and AOM treatment failure (AOMTF) occurred after publication of the Centers for Disease Control and Prevention AOM treatment guidelines advocating high dose amoxicillin in 1998 and the universal use of the pneumococcal conjugate vaccine in 2000.
This was a 9-year prospective study in a suburban, community-based private practice. To identify bacterial isolate(s), 551 children with AOM who had not responded after 1 or 2 empiric antimicrobial treatment courses (termed persistent AOM) and those who were failures after 48 h on treatment (AOMTF) underwent tympanocentesis. Three periods were compared: (1) 1995-1997 when all enrolled received standard dose amoxicillin (40-50 mg/kg/day divided 3 times daily) as the initial empiric treatment; (2) 1998-2000 when all received high dose amoxicillin (80-100 mg/kg/day divided twice daily); and (3) 2001-2003 when high dose amoxicillin and pneumococcal conjugate vaccinations were used.
Persistent AOM or AOMTF for which tympanocentesis was performed occurred in 195 (16.2%) of 1,207, 204 (16.1%) of 1,278 and 152 (12.3%) of 1,232 AOM visits for 1995-1997, 1998-2000 and 2001-2003, respectively; the 24% decline in 2001-2003 in persistent AOM and AOMTF was significant (P = 0.007). Middle ear aspirates grew Streptococcus pneumoniae (48, 44 and 31%) and Haemophilus influenzae (38, 43 and 57%) for time periods 1, 2 and 3, respectively. There was a significant decline in S. pneumoniae (P = 0.017) and increase in H. influenzae (P = 0.012) isolations and of H. influenzae that were beta-lactamase-producing (P = 0.04) among middle ear fluid isolates. Also there was a trend for an increased proportion of S. pneumoniae in 2001-2003 that were penicillin-susceptible (P = 0.17).
In our experience, persistent AOM and AOMTF has decreased in frequency since the introduction of high dose amoxicillin therapy and pneumococcal conjugate vaccination. It appears that H. influenzae has become the predominant pathogen of persistent AOM and AOMTF since universal immunization with the pneumococcal conjugate vaccine. Fewer S. pneumoniae AOM isolates are penicillin-resistant and more H. influenzae are beta-lactamase-producing.

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    ABSTRACT: Introduction: Although Streptococcus pneumoniae (SP), Haemophilus influenzae (HI), and Moraxella catarrhalis (MC) are major pathogenic bacteria of acute otitis media (AOM) in children, responsibility of their resistance to antimicrobial agents for intractable AOM has not been cleared. In this study, cultured bacteria from the adenoid of otitis-prone children were compared with those of children who had no apparent episodes of AOM to know the most responsible pathogens for intractable AOM. Methods: Sixty-eight children who had episodes of recurrent or persistent AOM were subjected to this study and 19 children without apparent episodes of AOM but with obstructive sleep apnea were taken as controls. Nasopharyngeal swab specimens were obtained from the adenoid transorally during the adenoidectomy, instead of conventional transnasal harvesting, to avoid contamination. Prevalence of SP, HI, and MC in each group was compared using the chi-squared or Fischer's exact test, and p-values <0.05 were considered significant. Results: SP was identified in 60.3% of otitis-prone children and in 52.6% of control children, and this difference indicated no statistically significance (p=0.54). HI was isolated from 77.9% of subjects and from 47.4% of controls, and the difference revealed significant (p=0.009). Above all, beta-lactamase negative HI (BLNAR) was caught in 39.7% of the study group, but in none of the control group (p=0.002). MC was identified in 32.4% and in 5.3%, individually, with significant difference (p=0.04). Conclusion: HI was more frequently isolated from otitis-prone children, and was considered to make AOM more intractable. The pathogenic role of MC for AOM may be evident.
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    ABSTRACT: Background We sought to determine if nasopharyngeal (NP) cultures taken at times of healthy visits or at onset of acute otitis media (AOM) could predict the otopathogen mix and antibiotic-susceptibility of middle ear isolates as determined by middle ear fluid (MEF) cultures obtained by tympanocentesis.Methods During a 7-year-prospective study of 619 children from Jun 2006-Aug 2013, NP cultures were obtained from 6-30 month olds at healthy visits and NP and MEF (by tympanocentesis) at onset of AOM episodes.Results2601 NP and 530 MEF samples were collected. During healthy visits, S. pneumoniae (Spn) was isolated from 656 (31.7%) NP cultures compared to 253 (12.2%) for Nontypeable Haemophilus influenzae (NTHi) and 723 (34.9%) for Moraxella catarrhalis (Mcat). At onset of AOM 256 (48.3%) of 530 NP samples were culture positive for Spn, 223 (42%) for NTHi and 251 (47.4%) for Mcat, alone or in combinations. At 530 AOM visits, Spn was isolated from 152 (28.7%) of MEF compared to 196 (37.0%) for NTHi and 104 (19.6%) for Mcat. NP cultures collected at onset of AOM but not when children were healthy had predictive value for epidemiologic antibiotic susceptibility pattern assessments.ConclusionsNP cultures at onset of AOM more closely correlate with otopathogen mix than NP cultures at healthy visits using MEF culture as the gold standard, but the correlation was too low to allow NP cultures to be recommended as a substitute for MEF culture. For epidemiology purposes, antibiotic susceptibility of MEF isolates can be predicted by NP culture results when samples are collected at onset of AOM.
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