Blood culture and respiratory syncytial virus identification in acute lower respiratory tract infection.

Even though the incidence of pneumonia in developed and developing countries is similar, the mortality is five times higher in developing countries. This study aimed to determine the prevalence of bacteremia in children with acute lower respiratory tract infection (LRTI) and relative contribution of respiratory syncytial virus (RSV). One hundred and one children under five years of age who attended a primary care level clinic with diagnosis of acute LRTI, were enrolled. Diagnosis and management of pneumonia were done according to the WHO guidelines. Two blood cultures were drawn at the time of admission. A nasopharyngeal sample was taken for detection of RSV by indirect immunofluorescence. Blood cultures were positive for pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus) in three patients. The detection for RSV was positive in 24 patients (23.7%). The clinical and radiographic presentations were not significantly different between patients with and without RSV (p > 0.05). RSV is a common cause of LRTI in children younger than five years old. Blood cultures are not commonly positive in outpatients with acute LRTI. The practice of obtaining blood cultures in primary and secondary care clinics is not useful to guide the treatment of patients with community-acquired pneumonia.

Streptococcus pneumoniae: low frequency of penicillin resistance and high resistance to trimethoprim-sulfamethoxazole in nasopharyngeal isolates from children in a rural area in Mexico.

Due to the changes in the frequency of penicillin-resistant strains of S. pneumoniae, it is necessary to perform surveillance studies of bacterial resistance. Isolates from the upper respiratory tract of asymptomatic children have been useful. There is no information about the difference between isolates from children with and without upper respiratory tract infection (URTI). The objective of the authors in this paper is to establish the prevalence of carrier-state, serotype and antimicrobial resistance of S. pneumoniae isolates from children with and without acute upper respiratory tract infection (URTI) in a rural area in Mexico. A cross-sectional comparative study was performed in Tlaxcala, Mexico. Children from one month 5 years of age were included. Nasopharyngeal swabs were obtained. Identification was done by international microbiology standards. Serotyping was done by the capsular Quellung test. The susceptibility testing was performed by the agar dilution method. Four-hundred and fifty patients were included. S. pneumoniae was isolated in 134 children (29.7%). Frequency of carriers was greater in patients with URTI (107/323) than without URTI (27/127) (33.1% vs. 21.1% p = 0.012, OR 1.84, IC 95% 1.1-3.08). The six most frequent serotypes were: 6B (16.4%); 19F (11.9%); 19A (6.7%); 14, 23F, and 35 (5.2% each), with no difference among the groups. Only 3% of the strains had high level resistance to penicillin, and 12.6% had intermediate resistance, and for ampicillin 4%, amoxicillin 4%, amoxicillin-clavulanate 4%, ceftriaxone 3%, cefotaxime 1.5%, erythromycin 6%, miocamycin 3%, chloramphenicol 4%, and vancomycin 0%. Trimethoprim-sulfamethoxazole resistance was very high (42%). In conclusion, colonization is higher in children with URTI. Five of the most frequent serotypes identified in this study were the same as those identified in patients with S. pneumoniae invasive diseases in Mexico City. In Tlaxcala, Mexico, beta-lactams could be the drug of choice for the treatment of S. pneumoniae lower respiratory tract infections. It is necessary to perform clinical assays to evaluate the efficacy of trimethoprim-sulfamethoxazole due to the high resistance in vitro.