Diagnostic detection of Streptococcus pneumoniae PpmA in urine

• Published in: Clinical microbiology and infection Vol. 15; no. 5; pp. 443 - 453
• Main Authors: García-Suárez, M.d.M., Cron, L.E., Suárez-Álvarez, B., Villaverde, R., González-Rodríguez, I., Vázquez, F., Hermans, P.W.M., Méndez, F.J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Elsevier Ltd 01-05-2009; Blackwell Publishing Ltd; Wiley-Blackwell
• Subjects: Amino Acid Sequence; Animals; Antigens, Bacterial - urine; Bacterial diseases; Bacterial Proteins - urine; Biological and medical sciences; Blotting, Western - methods; Child; Child, Preschool; Diagnosis; Female; Human bacterial diseases; Humans; Infant; Infant, Newborn; Infectious diseases; Male; Medical sciences; Molecular Sequence Data; pneumococcal infection; Pneumococcal Infections - diagnosis; proteinase maturation protein A (PpmA); proteinase maturation protein A (PpmA); Rabbits; Sensitivity and Specificity; Sequence Alignment; Staphylococcal infections, streptococcal infections, pneumococcal infections; Streptococcus pneumoniae; Streptococcus pneumoniae - immunology; urine; Urine - microbiology; proteinase maturation protein A (PpmA); Diagnosis; pneumococcal infection; urine; Streptococcus pneumoniae; Infection; Urine; Streptococcaceae; Streptococcal infection; Bacteriosis; Bacteria; Micrococcales; Protein A; Pneumococcal infection
• ISSN: 1198-743X; 1469-0691
• DOI: 10.1111/j.1469-0691.2009.02702.x

Streptococcus pneumoniae infections are often difficult to diagnose accurately, as it is not uncommon for clinical samples to be culture-negative, particularly after antibiotic administration. The rapid Binax NOW S. pneumoniae urinary antigen test lacks specificity in children, owing to pneumococcal antigen reactions in children who are nasopharyngeal carriers of S. pneumoniae. A western blot assay with a specific polyclonal antibody was developed for direct detection of the putative proteinase maturation protein A (PpmA) in urine samples from children with pneumococcal infections. The sensitivity and specificity of the assay were 66.7% and 100%, respectively. Previous antibiotic treatment or S. pneumoniae nasopharyngeal colonization did not affect PpmA antigenuria. Results also demonstrated the presence of PpmA cross-reactive epitopes in commensal bacteria that co-colonize the nasopharyngeal niche, although the non-pneumococcal cross-reactive protein(s) did not interfere with the detection assay. S. pneumoniae PpmA in the urine of children with pneumococcal infections may be a marker that has the potential to be used in the clinical diagnosis of pneumococcal infection.