RESUMO
The objective of this study was to assess the clinical performances of PhenoMATRIX and PhenoMATRIX PLUS for the screening of methicillin-resistant Staphylococcus aureus (MRSA) from nasal and inguinal/perineal ESwabs using chromogenic media. The automated performances were compared to the manual reading. Additionally, we evaluated PhenoMATRIX PLUS for the automatic release of the negative results to the Laboratory Information System (LIS) and the automatic discharge of the negative plates from the incubators. A total of 6,771 non-duplicate specimens were used by PhenoMATRIX as a machine learning model. The validation of these settings was performed on 17,223 non-duplicate specimens. The MRSA positivity rate was 5% (866/17,223). Validated settings were then used by PhenoMATRIX PLUS on another 1,409 non-duplicate specimens. The sensitivities of PhenoMATRIX and PhenoMATRIX PLUS were 99.8% [95% confidence interval (CI), 99.2%-99.9%] and 100% (95% CI, 92.1%-100%), respectively. The specificities of PhenoMATRIX and PhenoMATRIX PLUS were 99.1% (95% CI, 99.0%-99.2%) and 95.2% (95% CI, 93.8%-96.1%), respectively. All the 1,297 MRSA-negative specimens analyzed by PhenoMATRIX PLUS were automatically released and sent to the LIS immediately after availability of the culture image on the WASPLab (100% accuracy). All negative media plates were automatically discarded. PhenoMATRIX PLUS decreases the time spent by technologists on negative plates and ensures optimal usage of the incubators' capacity.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Humanos , Técnicas Bacteriológicas/métodos , Sensibilidade e Especificidade , Compostos Cromogênicos , Nariz , Infecções Estafilocócicas/diagnóstico , Meios de CulturaRESUMO
Diagnostic laboratories in Aotearoa, New Zealand (NZ) refer cultures from faecal samples positive for Shiga toxin genes to the national Enteric Reference Laboratory for isolation of Shiga toxin-producing Escherichia coli (STEC) for epidemiological typing. As there was variation in the culture media being referred, a panel of 75 clinical isolates of STEC, representing 28 different serotypes, was used to assess six commercially available media and provide guidance to clinical laboratories. Recommendations were subsequently tested for a 3-month period, where STEC isolations and confirmations were assessed by whole genome sequencing analysis against the culture media referred. CHROMagar™ STEC (CH-STEC; CHROMagar Microbiology, Paris, France) or CH-STEC plus cefixime-tellurite sorbitol MacConkey agar was confirmed inferior to CH-STEC plus blood agar with vancomycin, cefsulodin, and cefixime (BVCC). The former resulted in fewer STEC types (n = 18) being confirmed compared to those from a combination of CH-STEC and BVCC (n = 42). A significant (P < .05) association with an STEC's ability to grow on CH-STEC and the presence of the ter gene cluster, and eae was observed. Culturing screen positive STEC samples onto both CH-STEC and BVCC ensures a consistently higher recovery of STEC from all clinical samples in NZ than CH-STEC alone.
Assuntos
Infecções por Escherichia coli , Proteínas de Escherichia coli , Escherichia coli Shiga Toxigênica , Humanos , Escherichia coli Shiga Toxigênica/genética , Cefixima , Ágar , Nova Zelândia , Meios de Cultura , Vancomicina , Cefsulodina , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genéticaRESUMO
Non-albicans Candida species are emerging in the nosocomial environment, with the multidrug-resistant (MDR) species Candida auris being the most notorious example. Consequently, rapid and accurate species identification has become essential. The objective of this study was to evaluate five commercially available chromogenic media for the presumptive identification of C. auris Two novel chromogenic formulations, CHROMagar Candida Plus (CHROMagar) and HiCrome C. auris MDR selective agar (HiMedia), and three reference media, CandiSelect (Bio-Rad), CHROMagar Candida (CHROMagar), and Chromatic Candida (Liofilchem), were inoculated with a collection of 9 genetically diverse C. auris strains and 35 strains from closely related comparator species. After 48 h of incubation, the media were evaluated for their ability to detect and identify C. auris All media had the same limitations in the differentiation of the more common species Candida dubliniensis and Candida glabrata Only on CHROMagar Candida Plus did C. auris colonies develop a species-specific coloration. Nevertheless, the closely related pathogenic species Candida pseudohaemulonii and Candida vulturna developed a similar appearance as C. auris on this medium. CHROMagar Candida Plus was shown to be superior in the detection and identification of C. auris, with 100% inclusivity for C. auris compared to 0% and 33% for the reference media and HiCrome C. auris MDR selective agar, respectively. Although C. vulturna and C. pseudohaemulonii can cause false positives, CHROMagar Candida Plus was shown to be a valuable addition to the plethora of mostly molecular methods for C. auris detection and identification.
Assuntos
Candida , Compostos Cromogênicos , Meios de Cultura , Humanos , Saccharomycetales , Especificidade da EspécieRESUMO
This study aimed to evaluate the diagnostic performance (specificity, Sp; sensitivity, Se; accuracy; positive predictive value; negative predictive value; and Cohen's kappa coefficient, κ, of agreement) of chromogenic culture media for rapid identification of microorganisms isolated from cows with clinical (CM) and subclinical mastitis (SCM). For this, 2 experiments were carried out: evaluation of (1) biplate, and (2) triplate of chromogenic culture media for rapid identification of mastitis-causing microorganisms. For the evaluation of diagnostic performance, identification of microorganisms by MALDI-TOF mass spectrometry was considered the standard methodology. In experiment 1, 476 milk samples collected from cows with CM and 660 from cows with SCM were evaluated by inoculation in 2 selective chromogenic culture media (CHROMagar) for gram-positive bacteria and another for gram-negative bacteria. In experiment 2, 476 milk samples from cows with CM and 500 from cows with SCM were evaluated by inoculation in triplate chromogenic culture media (Smartcolor2, Onfarm), selective for Streptococcus and Strep-like organisms, Staphylococcus, and gram-negative bacteria. In experiment 1 for the CM samples, the use of biplates with gram-positive and gram-negative culture media showed Se that ranged from 0.56 (0.32-0.81; Staphylococcus aureus) to 0.90 (0.80-0.99 Streptococcus uberis), Sp varied from 0.94 (0.92-0.96; Strep. uberis) to 1.00 (Prototheca spp. or yeast), and κ ranged from 0.47 (0.26-0.67; Staph. aureus) to 0.84 (0.78-0.9; Escherichia coli). The Se of biplates for SCM samples ranged from 0.50 (0.15-0.85; E. coli) to 0.94 (0.87-1.00; Staph. aureus), Sp varied from 0.95 (0.93-0.97; Strep. uberis) to 0.99 (0.98-1.00; Staph. aureus and Strep. Agalactiae or dysgalactiae), and κ ranged from 0.18 (0.00-0.40; Escherichia coli) to 0.88 (0.80-0.95; Staph. aureus). In experiment 2, the Se of the triplate chromogenic media in CM samples ranged from 0.09 (0.00-0.26; Serratia spp.) to 0.94 (0.85-1.00; Klebsiella spp. and Enterobacter spp.), Sp varied from 0.94 (0.92-0.96; Strep. agalactiae and Strep. dysgalactiae) to 1.00 (Serratia spp.) and κ ranged from 0.07 (0.00-0.24; Serratia spp.) to 0.85 (0.75-0.94; Klebsiella spp. and Enterobacter spp.). For SCM samples, the use of the triplate with the chromogenic culture media showed Se that varied from 0.25 (0.10-0.40; Lactococcus spp.) to 1.00 (Strep. Agalactiae or dysgalactiae), Sp ranged from 0.92 (0.90-0.94; Strep. Agalactiae and Strep. dysgalactiae) to 0.99 (0.98-1.00; Klebsiella spp. and Enterobacter spp.), and κ varied from 0.28 (0.00-0.72; E. coli) to 0.72 (0.60-0.82; Staph. aureus). Our results suggest that the diagnostic accuracy of the biplate and triplate of chromogenic culture media varies according to pathogen, and the results of chromogenic culture media may be useful for rapid decision-making on mastitis treatment protocols of the main mastitis-causing microorganisms, but their use for implementation of mastitis control measures will depend on each farm specific needs.
Assuntos
Doenças dos Bovinos , Mastite Bovina , Mastite , Infecções Estreptocócicas , Animais , Bovinos , Meios de Cultura , Escherichia coli , Feminino , Mastite/veterinária , Mastite Bovina/diagnóstico , Leite , Infecções Estreptocócicas/diagnóstico , Infecções Estreptocócicas/veterinária , StreptococcusRESUMO
Group B Streptococcus (GBS) can be found to colonize about 25% of all healthy, adult women and is the leading infectious cause of early neonatal morbidity and mortality in the United States. This study evaluated the clinical performance of PhenoMatrix (PM) chromogenic detection module (CDM) digital imaging software in detection of GBS from LIM broth plated on ChromID Strepto B chromogenic medium (ChromID) using the WASP automated processor. The performance of the PM CDM was compared to manual culture review of the digital images and molecular detection of GBS. ChromID alone had a sensitivity and specificity of 84.5% and 94.7%, respectively, after 48 h compared to nucleic acid amplification testing (NAAT). Compared to the composite reference for positivity, when PM CDM was used to detect GBS from ChromID, the sensitivity was 100%, with no true-positive GBS isolates missed by 48 h of incubation. Overall, evaluating all three methods for the detection of GBS, the sensitivities of NAAT, ChromID plus PM CDM at 48 h, and ChromID alone at 48 h were 96.8%, 95.5%, and 90.3%, respectively. The specificities of NAAT, ChromID plus PM CDM, and ChromID alone were 97.7%, 63.0%, and 95.4%, respectively. The sensitivity of ChromID in combination with the PM CDM was similar to the sensitivity of molecular detection. Further, the algorithm never called a culture negative that was determined to be positive by manual reading, and it identified an additional eight true positive specimens that were missed by manual digital image culture reading.
Assuntos
Complicações Infecciosas na Gravidez , Infecções Estreptocócicas , Adulto , Algoritmos , Técnicas Bacteriológicas , Meios de Cultura , Feminino , Humanos , Recém-Nascido , Gravidez , Sensibilidade e Especificidade , Infecções Estreptocócicas/diagnóstico , Streptococcus agalactiae , VaginaRESUMO
BACKGROUND: The number of invasive Candida infections has significantly increased in recent decades. For the successful treatment of fungal infections, rapid identification at the species level, particularly in polyfungal infections, is a key factor. In this study, four commercially available chromogenic media, CandiSelect™ 4 (CS4), chromID™ Candida Agar (CCA), BBL™ CHROMagar™ Candida Medium (BBL) and Brilliance™ Candida Agar (BCA) were evaluated for Candida identification. MATERIAL/METHODS: Overall, 181 bronchial secretion samples from intensive care patients were analysed prospectively. In addition, 18 primarily sterile materials, previously tested positive for Candida, were investigated retrospectively. All samples were cultured as recommended by the manufacturer and visually inspected after 24 and 48 hours by three independent investigators. As a control, colonies were identified by MALDI-TOF MS. Specificity and sensitivity were determined for C albicans identification prospectively. RESULTS: CS4 and BCA showed the best overall consensus with the identification results reached by MALDI-TOF MS for Candida albicans and species. A clear differentiation between the species could be ascertained via easily identifiable, species-specific coloration in contrast to BBL and CCA. Sensitivity for C albicans (n = 73) identification varied between 32% (BCA) and 69% (CS4 and CCA) after 24 hours and 68% (BBL) and 82% (BCA) after 48 hours incubation, while specificity ranged between 62% (BBL) and 81% (CCA) after 24 hours and 82% (BBL) and 85% (CS4) after 48 hours. CONCLUSION: CS4 and BCA are recommended for routine identification of Candida species in human samples.
Assuntos
Candida , Candidíase/diagnóstico , Técnicas de Tipagem Micológica/métodos , Candida/crescimento & desenvolvimento , Candida/isolamento & purificação , Candida albicans/crescimento & desenvolvimento , Candida albicans/isolamento & purificação , Humanos , Estudos Retrospectivos , Sensibilidade e Especificidade , Especificidade da EspécieRESUMO
Urine cultures are among the most common specimens received by clinical laboratories and generate a major share of the laboratory workload. Chromogenic agar can expedite culture results, but technologist review is still needed. In this study, we evaluated the ability of the WASPLab software to interpret urine specimens plated onto chromID CPS Elite (CPSE) agar. Urine specimens submitted for bacterial culture were plated onto CPSE agar with a 1-µl loop using the WASP. Each plate was imaged after 0 and 18 h of incubation, and colonies were enumerated by color using the WASPLab software and a technologist's reading from a high-definition (HD) monitor. The results were reported as negative if <10 colonies/plate were detected. Laboratory information system (LIS) time stamps were used to measure the time to result. A total of 1,581 urine cultures were tested. The sensitivity and specificity of the software were 99.8% and 68.5%, respectively, which included 2 manual-positive/automation-negative (MP/AN) results and 170 manual-negative/automation-positive (MN/AP) results. Of the 170 MN/AP specimens, 116 were caused by microcolonies missed by the technologist. The remaining MN/AP results were caused by either count differences near the 10-colony threshold (n = 43) or count differences of >50 CFU (n = 11). The use of both CPSE agar and the WASPLab software improved the time to result for urine culture, reducing the average time to result by 4 h 42 min for negative specimens and 3 h 28 min for positive specimens compared to that with standard-of-care testing. These data demonstrate that the use of CPSE agar and automated plate reading has the potential to improve turnaround time while maintaining high sensitivity and reducing urine culture workload.
Assuntos
Automação Laboratorial , Técnicas Bacteriológicas , Software , Urinálise/métodos , Compostos Cromogênicos , Meios de Cultura , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Urinálise/normas , Infecções Urinárias/diagnóstico , Infecções Urinárias/microbiologiaRESUMO
In the last 25 years, chromogenic culture media have found widespread application in diagnostic clinical microbiology. In the last decade, the range of media available to clinical laboratories has expanded greatly, allowing specific detection of additional pathogens, including Pseudomonas aeruginosa, group B streptococci, Clostridium difficile, Campylobacter spp., and Yersinia enterocolitica. New media have also been developed to screen for pathogens with acquired antimicrobial resistance, including vancomycin-resistant enterococci, carbapenem-resistant Acinetobacter spp., and Enterobacteriaceae with extended-spectrum ß-lactamases and carbapenemases. This review seeks to explore the utility of chromogenic media in clinical microbiology, with particular attention given to media that have been commercialized in the last decade. The impact of laboratory automation and complementary technologies such as matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is also assessed. Finally, the review also seeks to demarcate the role of chromogenic media in an era of molecular diagnostics.
Assuntos
Meios de Cultura/normas , Técnicas Microbiológicas/métodos , Técnicas Microbiológicas/tendências , Bactérias/isolamento & purificação , Compostos Cromogênicos , Humanos , Técnicas Microbiológicas/instrumentação , Técnicas Microbiológicas/normasRESUMO
Similar to mecA, mecC confers resistance against beta-lactams, leading to the phenotype of methicillin-resistant Staphylococcus aureus (MRSA). However, mecC-harboring MRSA strains pose special difficulties in their detection. The aim of this study was to assess and compare different phenotypic systems for screening, identification, and susceptibility testing of mecC-positive MRSA isolates. A well-characterized collection of mecC-positive S. aureus isolates (n = 111) was used for evaluation. Routinely used approaches were studied to determine their suitability to correctly identify mecC-harboring MRSA, including three (semi)automated antimicrobial susceptibility testing (AST) systems and five selective chromogenic agar plates. Additionally, a cefoxitin disk diffusion test and an oxacillin broth microdilution assay were examined. All mecC-harboring MRSA isolates were able to grow on all chromogenic MRSA screening plates tested. Detection of these isolates in AST systems based on cefoxitin and/or oxacillin testing yielded overall positive agreements with the mecC genotype of 97.3% (MicroScan WalkAway; Siemens), 91.9% (Vitek 2; bioMérieux), and 64.9% (Phoenix, BD). The phenotypic resistance pattern most frequently observed by AST devices was "cefoxitin resistance/oxacillin susceptibility," ranging from 54.1% (Phoenix) and 83.8% (Vitek 2) to 92.8% (WalkAway). The cefoxitin disk diffusion and oxacillin broth microdilution assays categorized 100% and 61.3% of isolates to be MRSA, respectively. The chromogenic media tested confirmed their suitability to reliably screen for mecC-harboring MRSA. The AST systems showed false-negative results with varying numbers, misidentifying mecC-harboring MRSA as methicillin-susceptible S. aureus This study underlines cefoxitin's status as the superior surrogate mecC-positive MRSA marker.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Cefoxitina/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana/métodos , Oxacilina/farmacologia , Proteínas de Ligação às Penicilinas/genética , Infecções Estafilocócicas/microbiologia , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Fenótipo , Infecções Estafilocócicas/diagnósticoRESUMO
The aim of this study was to evaluate the usefulness of chromogenic media for isolation of bacteria from urine and direct identification of UTI pathogens. A total of 100 urine specimens were inoculated on blood agar and MacConkey agar as a reference method and on the following media to be tested: chromID® CPS® Elite (CPSE, bioMérieux), CHROMagarTM Orientation (BioMaxima), BD CHROMagar Orientation Medium (ORI, Becton Dickinson), CHROMagarTM Orientation (ORIE, Graso) and Brillance UTI Clarity Agar (UTI C, Oxoid). After a 24-hour incubation period, 47 Gram-positive cocci and 62 Gram-negative rods were observed. The specificity and sensitivity of all chromogenic media was 97.3% and 93.5% respectively for qualitative diagnostic; and 81.9% and 81.3% respectively for semi-quantitative diagnostic. The mean PPV and NPV of the chromogenic media were 98.7% and 87.7% for qualitative UTI diagnostic, and 90.9% and 71.9% respectively for semi-quantitative diagnostic.
Assuntos
Bactérias/isolamento & purificação , Infecções Bacterianas/urina , Compostos Cromogênicos/química , Meios de Cultura/química , Infecções Urinárias/diagnóstico , Ágar/química , Infecções Bacterianas/microbiologia , Contagem de Colônia Microbiana , Escherichia coli/isolamento & purificação , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Sensibilidade e Especificidade , Infecções Urinárias/microbiologiaRESUMO
Sanita-kun™ CC (coliform count) and EC (Escherichia coli/coliform count), sheet quantitative culture systems which can avoid chromogenic interference by lactase in food, were evaluated in comparison with conventional methods for these bacteria. Based on the results of inclusivity and exclusivity studies using 77 micro-organisms, sensitivity and specificity of both Sanita-kun™ met the criteria for ISO 16140. Both media were compared with deoxycholate agar, violet red bile agar, Merck Chromocult™ coliform agar (CCA), 3M Petrifilm™ CC and EC (PEC) and 3-tube MPN, as reference methods, in 100 naturally contaminated food samples. The correlation coefficients of both Sanita-kun™ for coliform detection were more than 0·95 for all comparisons. For E. coli detection, Sanita-kun™ EC was compared with CCA, PEC and MPN in 100 artificially contaminated food samples. The correlation coefficients for E. coli detection of Sanita-kun™ EC were more than 0·95 for all comparisons. There were no significant differences in all comparisons when conducting a one-way analysis of variance (anova). Both Sanita-kun™ significantly inhibited colour interference by lactase when inhibition of enzymatic staining was assessed using 40 natural cheese samples spiked with coliform. Our results demonstrated Sanita-kun™ CC and EC are suitable alternatives for the enumeration of coliforms and E. coli/coliforms, respectively, in a variety of foods, and specifically in fermented foods. SIGNIFICANCE AND IMPACT OF THE STUDY: Current chromogenic media for coliforms and Escherichia coli/coliforms have enzymatic coloration due to breaking down of chromogenic substrates by food lactase. The novel sheet culture media which have film layer to avoid coloration by food lactase have been developed for enumeration of coliforms and E. coli/coliforms respectively. In this study, we demonstrated these media had comparable performance with reference methods and less interference by food lactase. These media have a possibility not only to be useful alternatives but also to contribute for accurate enumeration of these bacteria in a variety of foods, and specifically in fermented foods.
Assuntos
Contagem de Colônia Microbiana/métodos , Meios de Cultura/química , Escherichia coli/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Microbiologia de Alimentos/métodos , Ágar/química , Técnicas de Cultura , Lactase/metabolismoRESUMO
MALDI-TOF mass spectrometry is now a routine resource in Clinical Microbiology, because of its speed and reliability in the identification of microorganisms. Its performance in the identification of bacteria and yeasts is perfectly contrasted. The identification of mycobacteria and moulds is more complex, due to the heterogeneity of spectra within each species. The methodology is somewhat more complex, and expanding the size of species libraries, and the number of spectra of each species, will be crucial to achieve greater efficiency. Direct identification from blood cultures has been implemented, since its contribution to the management of severe patients is evident, but its application to other samples is more complex. Chromogenic media have also contributed to the rapid diagnosis in both bacteria and yeast, since they accelerate the diagnosis, facilitate the detection of mixed cultures and allow rapid diagnosis of resistant species.
Assuntos
Técnicas de Tipagem Bacteriana/métodos , Técnicas de Tipagem Micológica/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Bactérias/classificação , Bactérias/isolamento & purificação , Infecções Bacterianas/microbiologia , Líquidos Corporais/microbiologia , Compostos Cromogênicos , Meios de Cultura , Fungos/classificação , Fungos/isolamento & purificação , Humanos , Micoses/microbiologia , Manejo de Espécimes , Coloração e Rotulagem , Fatores de TempoRESUMO
The current study was conducted to evaluate the ability to recover Salmonella from shell egg contents by culture methods. A total of 4,000 eggs were obtained from a grading and packing center located in the Gyeonggi Province of South Korea, and 200 samples were created by pooling 20 broken eggs. The pooled samples were held at room temperature for 4 d before a 25-mL aliquot of each pool was added to 225 mL of modified trypticase soy broth (mTSB) and incubated at 35°C for 24 ± 2 h. A loopful of the culture was streaked onto chromogenic Druggan-Forsythe-Iversen (DFI) agar and incubated at 36 ± 1°C for 18-24 h. In addition, 1 mL and/or 0.1 mL of the mTSB cultures were added to 10 mL of Muller-Kauffmann tetrathionate with novobiocin (MKTTn) or Rappaport-Vassiliadis (RV) broth, and they were incubated for 24 ± 2 h at 35 ± 2°C or 42 ± 0.2°C, respectively. A loopful from these cultures was streaked onto Brilliant Green (BG), xylose lysine deoxycholate (XLD), and bismuth sulfite (BS) agar plates, respectively. Directly streaking onto DFI agar revealed the presence of Salmonella in 14 out of the 200 pooled samples (7%); whereas the combination of RV medium and BG, XLD, and BS agar detected the pathogen in only 9 (4.5%), 7 (3.5%), and 3 (1.5%) of the pooled samples, respectively. When MKTTn broth was used, Salmonella was detected in 7 (3.5%), 2 (1%), and 0 (0%) of the samples when streaked onto BG, XLD, and BS agar, respectively. The results indicate that direct plating onto DFI agar without enrichment was the most suitable among the methods evaluated in this study for detecting Salmonella in raw shell egg contents with a low microbial load.
Assuntos
Carga Bacteriana , Meios de Cultura/química , Casca de Ovo/microbiologia , Ovos/microbiologia , Salmonella/isolamento & purificação , Animais , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Microbiologia de Alimentos , República da Coreia , SorotipagemRESUMO
The clinical laboratory methods used to diagnose yeast infections should be rapid, reliable, and capable of detecting mixed infections with species exhibiting a distinct antifungal susceptibility profile. In this study, we report the performance of a procedure combining the detection of mixed yeast cultures with a chromogenic medium and MALDI-TOF identification of the colonies. We then evaluated the impact that (i) the isolation medium and (ii) lowering the identification log score (LS) threshold value have on yeast identification performance in the routine laboratory.Among 15,661 clinical samples analyzed, 5,671 tested positive and 6,192 yeasts of 42 distinct species were identified. Overall, 6,117 isolates (98.79%) were identified on the first or second MALDI-TOF Mass Spectrometry (MS) attempt, yielding an average yeast species identification turnaround time of 0.346 days (95% CI [0.326 to 0.364]). The 75 remaining isolates were identified via nucleotide sequencing. Mixed infections accounted for 498 (8.78%) of the positive samples. The MALDI-TOF MS identification procedure performed well, regardless of the culture media tested. Lowering the recommended 2.0 LS threshold value to 1.8 would reduce the number of required (i) second MALDI-TOF MS identification attempts (178 vs. 490) and (ii) ITS2 and D1-D2 sequence-based identifications (17 vs. 75), while achieving an adequate identification rate (6,183/6,192, 99.85%).In conclusion, we propose applying a 1.8 LS threshold combined with chromogenic medium subculture to optimize the yeast identification workflow and detect mixed infection in the clinical laboratory.
Assuntos
Coinfecção/diagnóstico , Técnicas Microbiológicas/métodos , Micoses/diagnóstico , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Leveduras/classificação , Leveduras/isolamento & purificação , Coinfecção/microbiologia , Humanos , Micoses/microbiologia , Análise de Sequência de DNA/métodos , Fatores de Tempo , Fluxo de TrabalhoRESUMO
For the past decade, a number of chromogenic media for methicillin-resistance Staphylococcus aureus (MRSA) detection have been developed and applied, including Oxoid Brilliance™ MRSA, CHROMagar™ MRSA, BBL™ CHROMagar™ MRSA, MRSASelect and chromID MRSA. The advantages of these chromogenic media offers direct detection of visible staphylococcal colonies, coupled with the use of chromogenic enzymatic substrates that can be hydrolyzed by S. aureus to confirm species or strain identification. BBL™ CHROMagar™ MRSA and MRSASelect are designed for detection of nasal colonization by MRSA, while CHROMagar™ MRSA, Oxoid Brilliance™ MRSA and chromID MRSA are readily applied in bacterial screening. This review summarizes the characteristics, principles and capacities of these selective media, and focuses on comparison of different chromogenic media.
Assuntos
Meios de Cultura/química , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/diagnóstico , Compostos Cromogênicos/metabolismo , Diagnóstico Precoce , Humanos , Sensibilidade e EspecificidadeRESUMO
Timely and accurate identification of yeasts is essential for adequate treatment, considering the increase in antifungal resistance of some species, particularly for C. auris. Current matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) manufacturer's protocol for identification of yeasts requires 24- to 72-h cultivation on Sabouraud dextrose media (SAB), but not some of the mainstay primary culture media used in mycology such as inhibitory mold agar (IMA), Mycosel, CHROMagar Candida Plus, and CHROMagar Candida. As culture media can influence MALDI-TOF MS identification results, this study evaluated the accuracy and performance of identification of clinically relevant yeasts on these first-line media using the VITEK-MS MALDI-TOF MS system.IMPORTANCEIn this study, a panel of 140 strains (21 species) was used to assess the performance of the selected media. Although not in the manufacturer's list of accepted media, IMA and chromogenic media are suitable for the identification of yeasts on the VITEK-MS systems. CHROMagar Candida Plus allowed the identification of 135/140 isolates tested after 24-h incubation similar to SAB reference media (137/140). Yeast isolates that grew on Mycosel selective media were also reliably identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. VITEK-MS system with IVD database V3.2 correctly identified C. auris strains to the species level on CHROMagar Candida Plus alleviating the need for subcultivation and reduced turnaround time (24-72 h) to identification for patient screening.
RESUMO
Streptococcus agalactiae (Group B Streptococcus; GBS) is a leading cause of neonatal invasive disease worldwide. GBS can colonize the human gastrointestinal and genitourinary tracts, and the anovaginal colonization of pregnant women is the main source for neonatal infection. Streptococcus anginosus, in turn, can colonize the human upper respiratory, gastrointestinal, and genitourinary tracts but has rarely been observed causing disease. However, in the last years, S. anginosus has been increasingly associated with human infections, mainly in the bloodstream and gastrointestinal and genitourinary tracts. Although anovaginal screening for GBS is common during pregnancy, data regarding the anovaginal colonization of pregnant women by S. anginosus are still scarce. Here, we show that during the assessment of anovaginal GBS colonization rates among pregnant women living in Rio de Janeiro, Brazil, S. anginosus was also commonly detected, and S. anginosus isolates presented a similar colony morphology and color pattern to GBS in chromogenic media. GBS was detected in 48 (12%) while S. anginosus was detected in 17 (4.3%) of the 399 anovaginal samples analyzed. The use of antibiotics during pregnancy and history of urinary tract infections and sexually transmitted infections were associated with the presence of S. anginosus. In turn, previous preterm birth was associated with the presence of GBS (p < 0.05). The correlation of GBS and S. anginosus with relevant clinical features of pregnant women in Rio de Janeiro, Brazil, highlights the need for the further investigation of these important bacteria in relation to this special population.
RESUMO
Yeast infections are challenging human and animal medicine due to low rates of detection and the emergence of unknown ecology isolates. The aim of this study was to verify the biochemical identification of yeasts and yeast-like microorganisms obtained from animals comparing the results with chromogenic media and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF MS). Between January and August 2023, yeast and yeast-like isolates from samples of animals with suspicion of mycosis were identified using Vitek® 2 Compact, Brilliance® Candida Agar and MALDI Biotyper® MSP. A total of 39 cases were included, and 45 isolations were obtained. Cryptococcus neoformans (15.5%, 7/45), Meyerozyma guilliermondii (13.3%, 6/45), Candida parapsilosis (11.1%, 5/45), Candida albicans and Candida tropicalis (8.9%, each one 4/45) were the most identified organisms. There was full agreement with the three identification methods in 71.1% (32/45) of the isolates, disagreement on species in 17.8% (8/45), disagreement on genus and species in 6.7% (3/45) and, in 4.4% (2/45), there was no matched pattern in MALDI-TOF to compare the results. Biochemical methods are a good option in laboratories where proteomics are not available, and chromogenic media enhances diagnostics by detecting mixed infections. Surveillance must be implemented to improve the detection of agents shared between humans and animals.