We performed a clinical evaluation of the Vitek MS matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) system with the commercial database version 2.0 for rapid identification of medically important yeasts as compared with the conventional phenotypic method API ID 32 C. We tested 161 clinical isolates, nine isolates from culture collections and five reference strains. In case of discrepant results or no identification with one or both methods, molecular identification techniques were employed. Concordance between both methods was observed with 160/175 isolates (91.42%) and misidentifications by both systems occurred only when taxa were not included in the respective databases, i.e., one isolate of Candida etchellsii was identified as C. globosa by Vitek MS and two isolates of C. orthopsilosis were identified as C. parapsilosis by API ID 32 C. Vitek MS could not identify nine strains (5.14%) and API ID 32 C did not identify 13 (7.42%). Vitek MS was more reliable than API ID 32 C and reduced the time required for the identification of clinical isolates to only a few minutes.
Mycological Typing Techniques/methods , Mycoses/diagnosis , Mycoses/microbiology , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Yeasts/classification , Yeasts/isolation & purification , Humans , Sensitivity and Specificity , Time Factors , Yeasts/chemistry , Yeasts/metabolism
Corneal Ulcer/microbiology , Corynebacterium Infections/microbiology , Corynebacterium/isolation & purification , Opportunistic Infections/microbiology , Aged , Bacterial Typing Techniques , Corynebacterium/classification , Corynebacterium/genetics , Disease Susceptibility , Humans , Male , Phenotype , Recurrence , Ribotyping , Species Specificity
Objetivo Recuperamos 22 aislados de estafilococos coagulasa negativos resistentes al linezolid de nuestro hospital para su identificación, sensibilidad, perfil epidemiológico, mecanismos de la resistencia al linezolid y posibles combinaciones antibióticas sinérgicas. Métodos La identificación de los aislados fue realizada mediante espectrometría de masas (Vitek-MS, BioMérieux). La sensibilidad se realizó con el sistema Vitek-2 (bioMérieux) y el método de microdilución en caldo según las recomendaciones del CLSI. Se realizó electroforesis en gel de campo pulsado (PFGE) para estudiar la relación genética de los aislados. Los mecanismos de la resistencia al linezolid fueron evaluados por PCR/secuenciación: presencia del gen cfr, mutaciones puntuales en el dominio V del ARN ribosomal 23S y mutaciones ribosomales adicionales (en los genes rplC, rplD y rplV). La actividad in vitro del linezolid fue estudiada por separado y en combinación con otros 3 antibióticos utilizando tiras de E-test. Resultados Veinte aislados fueron identificados como Staphylococcus epidermidis y 2 como Staphylococcus hominis. La PFGE demostró que los aislados pertenecían a diferentes clones: 21 de los aislados presentaron mutaciones en la región del dominio V del ARNr 23S y en el 54,5% fue encontrado el gen cfr. La administración previa de linezolid fue documentada en la mayor parte de casos. El linezolid en combinación con gentamicina mostró una actividad sinérgica en el 45,5% de los aislados. Conclusiones Staphylococcus epidermidis fue la especie de estafilococos coagulasa negativos resistentes al linezolid más frecuentes. Los valores de CMI fueron además elevados para otros antiestafilocócicos. Todas las cepas presentaron varios mecanismos de resistencia al linezolid. Nuestros datos sugieren que linezolid más gentamicina podría ser una combinación sinérgica frente a los estafilococos coagulasa negativos resistentes al linezolid(AU)
Objective We recovered 22 coagulase-negative staphylococci isolates in our hospital to study their identity, susceptibility, epidemiological profile, linezolid resistance mechanisms, and the possibilities of different antibiotic combinations. Methods Isolate identification was performed using mass spectrometry (Vitek-MS, bioMérieux). Susceptibility testing was carried out with the Vitek-2 system and the broth microdilution method according to CLSI guidelines. Pulsed-field gel electrophoresis (PFGE) was performed to analyze the genetic relationship between isolates. Linezolid resistance mechanisms were evaluated by PCR/sequencing: presence of cfr gene, point mutations in domain V of 23S ribosomal RNA and additional ribosomal mutations (in the rplC, rplD and rplV genes). The in vitro activity of linezolid was investigated alone and in combination with another three antibiotics acting on different cellular targets, using E-test strips. Results Twenty isolates were identified as Staphylococcus epidermidis, and 2 as Staphylococcus hominis. PFGE showed that isolates belonged to diverse clones, 21 of them presented mutations in the domain V region of 23S rRNA and the cfr gene was found in 54.5%. Prior administration of linezolid was documented in most of cases. Linezolid in combination with gentamicin showed a synergistic activity in 45.5% of isolates. Conclusions Staphylococcus epidermidis was the most prevalent linezolid-resistant coagulase-negative staphylococci. All isolates showed increased MIC values compared to other anti-staphylococcal drugs and several linezolid resistance mechanisms. Our data suggest that linezolid plus gentamicin could be a synergistic combination against linezolid-resistant coagulase-negative staphylococci(AU)
Humans , Drug Resistance, Bacterial , Anti-Bacterial Agents/therapeutic use , Staphylococcus/pathogenicity , Staphylococcal Infections/drug therapy , Coagulase , Microbial Sensitivity Tests
OBJECTIVE: We recovered 22 coagulase-negative staphylococci isolates in our hospital to study their identity, susceptibility, epidemiological profile, linezolid resistance mechanisms, and the possibilities of different antibiotic combinations. METHODS: Isolate identification was performed using mass spectrometry (Vitek-MS, bioMérieux). Susceptibility testing was carried out with the Vitek-2 system and the broth microdilution method according to CLSI guidelines. Pulsed-field gel electrophoresis (PFGE) was performed to analyze the genetic relationship between isolates. Linezolid resistance mechanisms were evaluated by PCR/sequencing: presence of cfr gene, point mutations in domain V of 23S ribosomal RNA and additional ribosomal mutations (in the rplC, rplD and rplV genes). The in vitro activity of linezolid was investigated alone and in combination with another three antibiotics acting on different cellular targets, using E-test strips. RESULTS: Twenty isolates were identified as Staphylococcus epidermidis, and 2 as Staphylococcus hominis. PFGE showed that isolates belonged to diverse clones, 21 of them presented mutations in the domain V region of 23S rRNA and the cfr gene was found in 54.5%. Prior administration of linezolid was documented in most of cases. Linezolid in combination with gentamicin showed a synergistic activity in 45.5% of isolates. CONCLUSIONS: Staphylococcus epidermidis was the most prevalent linezolid-resistant coagulase-negative staphylococci. All isolates showed increased MIC values compared to other anti-staphylococcal drugs and several linezolid resistance mechanisms. Our data suggest that linezolid plus gentamicin could be a synergistic combination against linezolid-resistant coagulase-negative staphylococci.
Acetamides/pharmacology , Anti-Infective Agents/pharmacology , Oxazolidinones/pharmacology , Staphylococcus/drug effects , Staphylococcus/genetics , Coagulase , Drug Resistance, Bacterial/genetics , Genotype , Humans , Linezolid , Microbial Sensitivity Tests , Phenotype
Facial Dermatoses/diagnosis , Tinea/diagnosis , Trichophyton/isolation & purification , Animals , Child , Diagnostic Errors , Facial Dermatoses/microbiology , Female , Guinea Pigs/microbiology , Herpesviridae Infections/diagnosis , Humans , Pets/microbiology , Rodent Diseases/microbiology , Tinea/microbiology , Tinea/transmission , Tinea/veterinary , Trichophyton/growth & development
