title: MALDI-TOF: a useful tool for laboratory identification of uncommon glucose non-fermenting Gram-negative bacteria associated with cystic fibrosis.
abstract: The predisposition of patients with cystic fibrosis (CF) for recurrent pulmonary infections can result in poor prognosis of the disease. Although the clinical significance in CF of micro-organisms, such as Staphylococcus aureus, Haemophilus influenzae and Pseudomonas aeruginosa, is well established, the implication of uncommon glucose non-fermenting Gram-negative bacilli (UGNF-GNB) in respiratory samples from CF patients is still unclear. Because of limitations of traditional methods used in most clinical laboratories, the accurate identification of these microbes is a challenge. Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) is an alternative tool for efficient identification of bacteria. This was a retrospective study to evaluate different identification methods in a collection of UGNF-GNB isolated from children with CF during a period of three years. The performance of MALDI-TOF was compared to that of 16S rDNA gene sequencing and to a conventional and automated phenotypic identification. The discriminatory power of MALDI-TOF (75.0 % agreement) was superior to automated techniques (67.1 % agreement) and to conventional phenotypical identification (50.0 % agreement). MALDI-TOF also demonstrated high accuracy in identifying Stenotrophomonas maltophilia, Achromobacter xylosoxidans and Chryseobacterium indologenes, but had limited utility in identifying Pandoraea spp. and some species of Acinetobacter and Chryseobacterium (other than C. indologenes). Although MALDI-TOF identified only 75 % of the isolates in comparison with 16S rDNA gene sequencing, the prompt identification and high discriminatory power exhibited by MALDI-TOF make it a useful tool for the characterization of micro-organisms that are difficult to identify using routine methods.
authors: Bacteriology Section, Hospital de Clínicas - Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors: Helena Aguilar Peres
authors: HAP
authors: Homem de Mello de Souza
authors: Pele Pequeno Príncipe Research Institute, Faculdades Pequeno Príncipe, Curitiba, PR, Brazil.|Bacteriology Section, Hospital de Clínicas - Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors: Libera Maria
authors: LM
authors: Dalla-Costa
authors: Immunochemistry Section, Laboratório Municipal de Curitiba, Curitiba, PR, Brazil.|Pele Pequeno Príncipe Research Institute, Faculdades Pequeno Príncipe, Curitiba, PR, Brazil.
authors: Fernando José
authors: FJ
authors: Vicenzi
authors: Bacteriology Section, Hospital de Clínicas - Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors: Dilair
authors: D
authors: Camargo de Souza
authors: Department of Pediatrics - Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors: Carlos Antônio
authors: CA
authors: Riedi
authors: Department of Pediatrics - Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors: Nelson Augusto Rosario
authors: NAR
authors: Filho
authors: Molecular Bacteriology Section, Laboratório Central de Saúde Pública do Estado LACEN-PR, Curitiba, PR, Brazil.|Department of Microbiology, School of Health and Biosciences, Pontifícia Universidade Católica do Paraná (PUC), Curitiba, PR, Brazil.
authors: Marcelo
authors: M
authors: Pilonetto
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications*; D005260:Female; D006090:Gram-Negative Bacteria / Q000737:chemistry* / Q000145:classification* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D007223:Infant; D008297:Male; D018410:Pneumonia, Bacterial / Q000175:diagnosis* / Q000382:microbiology; D012189:Retrospective Studies; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*