ABSTRACT
BACKGROUND: Mycoplasma pneumoniae is one of the most common causes of childhood community-acquired pneumonia (CAP), particularly in school-age children. Information regarding this infection in pre-school age children is lacking. OBJECTIVE: To determine the prevalence of M. pneumoniae in young children aged under 5 years with CAP. MATERIAL AND METHOD: This prospective study was conducted at Queen Sirikit National Institute of Child Health (QSNICH), Bangkok, Thailand between December 2001 and November 2002. We enrolled children aged 2 to 5 years with a clinical and radiological diagnosis of CAP. Acute and convalescent sera were collected and measured by using a particle agglutination test. Polymerase chain reaction (PCR) assay for M. pneumoniae was detected from nasopharyngeal secretions. Criteria for diagnosis were defined as > or = 4-found rising of mycoplasma antibody or titer > or = 1:160 with positive PCR. RESULTS: Thirteen out of 113 CAP patients were diagnosed as mycoplasma pneumonia. Three of them were diagnosed by > or = 4-fold rising of mycoplasma antibody while another 10 patients were diagnosed by mycoplasma titer > or = 1:160 with positive PCR for M. pneumoniae. Clinical symptoms and signs of these 13 mycoplasma pneumonia in young patients were fever (85%), cough (92%), dyspnea (85%), diarrhea (15%), rales (85%), wheezing or rhonchi (46%), and skin rash (15%). Leucocytosis (wbc > 15,000/cumm) was found in 46%. Chest x-rays revealed interstitial infiltration (71%), patchy infiltration (29%) and no pleural effusion was detected. Choices of antibiotic were erythromycin (31%), beta lactam antibiotics (61%), and antibiotic was not prescribed in one patient (8%). Sixty-nine percent of the patients improved, while 31% did not, possibly due to the use of beta lactam antibiotics, or non use of antibiotics. CONCLUSION: Mycopalsma pneumonia is not uncommon in children aged 2-5 years with CAP. Clinical signs, symptoms and radiological findings are non-specific and cannot be differentiated from other causes of CAP.