Laboratory investigation of acute otitis media in children

Abstract number: 1733_1035

Papavasileiou K., Papavasileiou H., Makri A., Varzakakos I., Nika E., Voyatzi A.

Introduction: Acute Otitis Media (AOM) is a common disease of childhood, and quite often the children attend the outpatient clinic for this reason. Risk factors for the development of AOM are: low socioeconomic status, gender and the use of various hygienic items.

Purpose: To evaluate the incidence of bacterial pathogens responsible for AOM in children and to monitor the change of their antimicrobial susceptibility through the five years of testing (2001–2005).

Material and Methods: A total of 960 middle-ear fluid samples were collected from infants and children with AOM symptomatology, who either were hospitalised or attended the ENT outpatient Clinic. The examined material study was divided in two different time periods: (A) 2001–2002: 260 samples and (B) 2003–2005: 700 samples. Identification and susceptibility tests were based on classical laboratory methods, according to NCCLS instructions. In all S. pneumoniae strains the MICs were defined with automated system (VITEK 2, bioMérieux).

Results: Out of 960 cultures, 725 (75.5%) were positive to one of more bacteria. The most prevalent bacteria were: S. aureus (25%), Ps. aeruginosa (16%), H. influenzae (14%), S. pneumoniae (10%) and Streptococcus pyogenes (GAS) (9%). A seasonal distribution has been detected in the incidence of AOM. In winter–spring time, especially S. pneumoniae, GAS and H. influenzae were most predominant.

Comparing the A and B periods, the resistance of S. pneumoniae to penicillin increased from 36% to 40%, to erythromycin from 26% to 28% whereas to cotrimoxazole it decreased from 52% to 40%. The determination of MICs showed that there has been a steady increase in the high-level resistance to penicillin of S. pneumoniae (MIC ≥ 2 mg/L) and frequently the strains were multiple resistant. Among S. aureus a significantly lower prevalence of resistance to oxacillin (36% versus 15%) and to erythromycin (25% versus 21%) was observed. The incidence of erythromycin resistance reduced among H. influenzae (25% versus 3%) and GAS (16% versus 14%) during the five-year period.

Conclusions: 1. S. aureus was the most predominant causative organism of AOM in children, followed by H. influenzae and S. pneumoniae. 2. Significant increased resistance of S. pneumoniae strains was not noted in the last years. 3. The variation on the pattern of antimicrobial resistance of H. influenzae and GAS is probably due to the more prudent use of antibiotics.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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