Clinical manifestations of children with microbiologically confirmed pertussis infection and antimicrobial susceptibility of isolated strains in a regional hospital in Japan, 2008-2012.

We conducted a retrospective study in 57 children (median age, 3.5 years; range, 1 month-14.5 years) with microbiologically confirmed pertussis infection over a recent 4-year period in a regional hospital in Japan. We obtained nasal swabs from all patients for Bordetella pertussis isolation as well as performed B. pertussis DNA detection using loop-mediated isothermal amplification (LAMP). Of the 57 cases, 34 (60%) were culture-positive and 57 (100%) were LAMP-positive. The frequency of each symptom was as follows: typical paroxysmal cough for over 14 days, 96% (55/57); paroxysms, 86% (49/57); posttussive vomiting, 33% (19/57); inspiratory whoop, 25% (14/57); and apnea, 12% (7/57). Hospitalization was required in 14 cases (25%), 93% (13/14) of which were aged <1 year. The proportion of patients previously immunized against diphtheria-tetanus-acellular pertussis vaccine (DTaP) was 19% (4/21) in children aged <1 year and 92% (11/12) in children aged ≥ 10 years. Minimum inhibitory concentrations for 6 antimicrobials (erythromycin, clarithromycin, azithromycin, minocycline, amoxicillin, and sulfamethoxazole/trimethoprim) were measured for 30 isolated strains, and all strains were susceptible to all aforementioned antimicrobials. Thus, an additional pertussis vaccination in older children is necessary, and the current macrolides-based treatment strategy is considered reasonable.

Assessment of the loop-mediated isothermal amplification assay for rapid diagnosis of Mycoplasma pneumoniae in pediatric community-acquired pneumonia.

Rapid diagnosis of Mycoplasma pneumoniae pneumonia is required for timely treatment with effective antibiotics; however, PCR-based methods are often too expensive and technologically intensive for general use in clinical practice. In this study, the efficacy of the loop-mediated isothermal amplification (LAMP) assay for diagnosis of M. pneumoniae pneumonia in clinical practice was prospectively evaluated. From July 2011 to March 2012, 531 children hospitalized for community-acquired pneumonia were enrolled. In all patients, throat swabs were obtained on admission for the detection of M. pneumoniae DNA, and paired serum samples were obtained to assay M. pneumoniae particle agglutination (PA) antibody titers. M. pneumoniae pneumonia was diagnosed by either a positive LAMP assay or an increase of 4-fold or greater in the PA titer. Overall, 271 children (51.0% of the patients with pneumonia) were diagnosed with M. pneumoniae pneumonia. Among these, 258 (95.2%) and 248 (91.5%) were identified by the LAMP assay and serological tests, respectively. When the results of serological tests were considered as standard, the sensitivity, specificity, and positive and negative predictive values of the LAMP assay were 94.8%, 91.9%, and 91.1% and 95.2%, respectively. The median duration of pharyngeal carriage, as measured by the LAMP assay, was 9.5 days. Thus, the LAMP assay is useful in the rapid diagnosis of M. pneumoniae pneumonia.