Development and evaluation of MALDI-TOF MS-based serotyping for Streptococcus pneumoniae.

Surveillance of Streptococcus pneumoniae serotypes is important for the successful implementation of vaccination strategies to prevent the spread of invasive pneumococcal diseases. The standard method of serotyping of pneumococcal isolates is the phenotypic Neufeld test, which is cost- and labor-intensive. Recently, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been implemented as a rapid, simple and inexpensive method for identifying species. We evaluated the performance of MALDI-TOF MS for serotyping ten major serotypes of S. pneumoniae in Japan (serotypes 3, 6B, 15A, 15C, 19A, 19 F, 23A, 24 F, 35B and 38) using the Biotyper and ClinProTools. After optimizing the settings, we validated their serotyping performance for serotypes 3, 15A and 19A using a separate set of isolates that were not used in the creation of the classification algorithms. A total of 574 isolates of S. pneumoniae collected from Japanese nationwide surveillance studies were included. Of these, 407 isolates belonged to the ten major serotypes. Biotyper and ClinProTools correctly identified 77.9 % and 84.0 %, respectively, of the ten major serotype isolates. The validation analysis included a total of 113 isolates of the serotypes 3, 15A and 19A isolates. Biotyper and ClinProTools correctly identified 85.0 % and 69.9 % of the validation cohort isolates, respectively. MALDI-TOF MS has the potential to discriminate the ten major S. pneumoniae serotypes prevalent in Japan.

Itraconazole prophylaxis for invasive Aspergillus infection in lung transplantation.

Invasive Aspergillus infection (IA) is a significant cause of morbidity in lung transplantation (LT). However, its optimal prophylaxis is unclear. We routinely administer itraconazole (ITCZ) prophylaxis to all patients undergoing LT. In this study, we retrospectively evaluated the duration of prophylaxis and risk factors of IA. Among 30 adult patients who underwent LT, 5 patients developed IA. All patients with IA stopped ITCZ treatment within 1 year. At least 1 year of ITCZ prophylaxis is essential for the prevention of IA. Cytomegalovirus infection, renal replacement therapy, and tracheotomy were risk factors for IA.

Regional dissemination of Acinetobacter species harbouring metallo-ß-lactamase genes in Japan.

Metallo-ß-lactamase (MBL) producers have been reported among the various Acinetobacter species worldwide. In this study, the epidemiology and molecular characteristics of carbapenemase-encoding genes and mobile elements were studied to analyse the regional dissemination of MBL genes in Acinetobacter species. From January 2001 to December 2006, 48 Acinetobacter isolates harbouring MBL genes identified from five hospitals in Kyoto and Shiga Prefecture, Japan were collected and analysed. The partial rpoB gene or the 16S-23S ribosomal RNA intergenic spacer region was sequenced to obtain a species-level identification. Molecular typing using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) was performed. Twenty-five Acinetobacter pittii isolates were divided into eight PFGE types and five sequence types (STs) using MLST. Nine Acinetobacter bereziniae isolates belonged to five PFGE types. Five Acinetobacter nosocomialis isolates were divided into two PFGE types and two STs. Three unclassified Acinetobacter species isolates were divided into two PFGE types. Eighteen of the 25 A. pittii isolates belonged to ST119 and were identified from four hospitals. The bla(IMP-19) gene was detected in 41 of 48 isolates, including all of the A. pittii ST119 isolates. The bla(IMP-1) and bla(IMP-11) genes were detected in four and three isolates, respectively. The MBL genes were all embedded within a class 1 integron as a gene cassette array: bla(IMP-19) -aac(6')-31-bla(OXA-21) -aadA1, catB8-like/aacA4-bla(IMP-1) and bla(IMP-11). This study is the first report demonstrating the regional dissemination of MBL-producing Acinetobacter species. A. pittii ST119 harbouring blaIMP-19 was widely spread throughout the Kyoto-Shiga region.