Bacterial identification in herniated intervertebral discs: a prospective cohort study.

BACKGROUND CONTEXT: Reports of Cutibacterium acnes isolated in cultures of intervertebral disc samples suggest it as possibly responsible for inflammatory conditions causing Modic changes on spinal magnetic resonance imaging (MRI). PURPOSE: Our objective was to investigate the prevalence of C. acnes in samples of intervertebral disc of patients with lumbar disc herniation; to investigate prognostic factors and the relationship of Modic changes with infection 1 year after microdiscectomy. STUDY DESIGN: Prospective cohort study. PATIENT SAMPLE: In this single-center study, patients consecutively operated on for disc herniation had samples of the disc, multifidus muscle and ligamentum flavum (as an indication of contamination) extracted for culture. OUTCOME MEASURES: Age, sex, alcohol and tobacco consumption, body mass index; function, pain, and Modic chances in MRI before surgery and MRI 1 year later; rate of disc, muscle and ligament infection (primary outcome); diabetes and corticoid use (confoundings). METHODS: The protruded disc, muscle and ligament samples were sent for culture analysis in up to 30 minutes. A subsample of 17 patients underwent next-generation sequencing (NGS) molecular analysis too. We performed descriptive analysis and comparison of groups of patients with and without infection or contamination using Student's t, Mann-Whitney, chi-square, or Fisher's exact tests as appropriate, and pre- and postsurgical comparisons with the Wilcoxon test. RESULTS: From January 2018 to September 2019, 112 patients underwent open lumbar microdiscectomy, 67 (59.8%) men. Cultures showed 7 (6.3%) positive cases in the disc (2 with C. acnes), 3 (2.7%) in the ligament, and 12 (10, 7%) in muscle. No evidence of a difference in Modic alterations pre- or postoperatively was found between patients with and without positive culture 1 year after surgery. No association was found between culture positivity and functional or pain differences either. NGS results were all negative for C. acnes. CONCLUSIONS: We identified infective bacterial presence in the herniated disc in less than 2% of patients with disc herniation. C. acnes was not identified in any disc microbiome analysis. No significant association was observed between positivity for tissue infection and any clinical prognostic factor.

Associations of SARS-CoV-2 cycle threshold values with age, gender, sample collection setting, and pandemic period.

Cycle threshold (Ct) values in COVID-19 reverse-transcription polymerase chain reaction (RT-PCR) tests estimate the viral load in biological samples. Studies have investigated variables associated with SARS-CoV-2 viral load, aiming to identify factors associated with higher transmissibility. Using the results from tests performed between May/2020-July/2022 obtained from the database of a referent hospital in Sao Paulo, Brazil, we investigated associations between Ct values and patient's age, gender, sample collection setting and pandemic period according to the predominant SARS-CoV-2 variant locally. We also examined variations in Ct values, COVID-19 incidence, mortality, and vaccination coverage over time. The study sample included 42,741 tests. Gender was not significantly associated with Ct values. Age, sample collection setting and the pandemic period were significantly associated with Ct values even after adjustment to the multivariable model. Results showed lower Ct values in older groups, during the Gamma and Delta periods, and in samples collected in emergency units; and higher Ct values in children under 10 years old, home-based tests, during the Omicron period. We found evidence of a linear trend in the association between age and Ct values, with Ct values decreasing as age increases. We found no clear temporal associations between Ct values and local indicators of COVID-19 incidence, mortality, or vaccination between February/2020-November/2022. Our findings suggest that SARS-CoV-2 Ct values, a proxy for viral load and transmissibility, can be influenced by demographic and epidemiological variables.

Neurocysticercosis: diagnosis via metagenomic next-generation sequencing.

A 68-year-old Brazilian woman had 3 months of progressive fatigue, difficulty walking and 18 kg weight loss. On examination, there was gait apraxia and executive dysfunction. MR scan of brain showed communicating hydrocephalus and a cerebrospinal fluid showed 105 white cells/µL (≤5), predominantly lymphocytes, protein of 1.35 g/L (0.15-0.45) and the glucose content of 0.06 mmol/L (3.3-4.4). We suspected an infective cause and used of metagenomic next-generation sequencing to diagnose neurocysticercosis. This case highlights the challenge of diagnosing chronic meningitis and the relevance of genetic approaches in diagnosing neurological infections.

Mobility restrictions during the COVID-19 pandemic and reduced outpatient HIV and syphilis testing in Brazil.

BACKGROUND: In the initial phases of the COVID-19 pandemic, strategies adopted to reduce the dissemination of SARS-CoV-2 relied on non-pharmacological interventions, including physical distancing. Mobility restrictions affected the availability and quality of care for many health conditions, including sexually transmitted infections. OBJECTIVE: To investigate the impact of the COVID-19 pandemic mobility restriction on syphilis and HIV testing in outpatient settings. METHODS: In this study, we collected the weekly number of syphilis and HIV tests performed in a referent laboratory in São Paulo, Brazil, as well as the percentage of positive tests between January 2019 and December 2021. We also retrieved data on retail and recreation mobility in São Paulo city using Google COVID-19 Community Mobility Reports. We explored the association between populational mobility and the number of weekly tests and the association between the number of weekly tests and the percentage of positive results during the pandemic period. The analyses were conducted separately for syphilis and HIV tests. RESULTS: We found that mobility restrictions during the COVID-19 pandemic have been associated with a significant decrease in both syphilis and HIV tests performed in outpatient settings. We also observed that the number of tests performed was inversely associated with the percentage of positive results for syphilis; this association was also apparent for HIV tests in the first wave of the pandemic in the graphic analysis. CONCLUSION: Taken together, our findings suggest an indirect impact of COVID-19 pandemic-related mobility restrictions on the uptake of diagnostic tests for HIV and syphilis and the potential adoption of targeted-testing strategies. Understanding the extent and complexity of COVID-19 aftermaths on specific conditions and communities is essential to build strategies to mitigate the long-term consequences of COVID-19.

Associations of SARS-CoV-2 cycle threshold values with age, gender, sample collection setting, and pandemic period

ABSTRACT Cycle threshold (Ct) values in COVID-19 reverse-transcription polymerase chain reaction (RT-PCR) tests estimate the viral load in biological samples. Studies have investigated variables associated with SARS-CoV-2 viral load, aiming to identify factors associated with higher transmissibility. Using the results from tests performed between May/2020-July/2022 obtained from the database of a referent hospital in Sao Paulo, Brazil, we investigated associations between Ct values and patient's age, gender, sample collection setting and pandemic period according to the predominant SARS-CoV-2 variant locally. We also examined variations in Ct values, COVID-19 incidence, mortality, and vaccination coverage over time. The study sample included 42,741 tests. Gender was not significantly associated with Ct values. Age, sample collection setting and the pandemic period were significantly associated with Ct values even after adjustment to the multivariable model. Results showed lower Ct values in older groups, during the Gamma and Delta periods, and in samples collected in emergency units; and higher Ct values in children under 10 years old, home-based tests, during the Omicron period. We found evidence of a linear trend in the association between age and Ct values, with Ct values decreasing as age increases. We found no clear temporal associations between Ct values and local indicators of COVID-19 incidence, mortality, or vaccination between February/2020-November/2022. Our findings suggest that SARS-CoV-2 Ct values, a proxy for viral load and transmissibility, can be influenced by demographic and epidemiological variables.

Mobility restrictions during the COVID-19 pandemic and reduced outpatient HIV and syphilis testing in Brazil

Abstract Background In the initial phases of the COVID-19 pandemic, strategies adopted to reduce the dissemination of SARS-CoV-2 relied on non-pharmacological interventions, including physical distancing. Mobility restrictions affected the availability and quality of care for many health conditions, including sexually transmitted infections. Objective To investigate the impact of the COVID-19 pandemic mobility restriction on syphilis and HIV testing in outpatient settings. Methods In this study, we collected the weekly number of syphilis and HIV tests performed in a referent laboratory in São Paulo, Brazil, as well as the percentage of positive tests between January 2019 and December 2021. We also retrieved data on retail and recreation mobility in São Paulo city using Google COVID-19 Community Mobility Reports. We explored the association between populational mobility and the number of weekly tests and the association between the number of weekly tests and the percentage of positive results during the pandemic period. The analyses were conducted separately for syphilis and HIV tests. Results We found that mobility restrictions during the COVID-19 pandemic have been associated with a significant decrease in both syphilis and HIV tests performed in outpatient settings. We also observed that the number of tests performed was inversely associated with the percentage of positive results for syphilis; this association was also apparent for HIV tests in the first wave of the pandemic in the graphic analysis. Conclusion Taken together, our findings suggest an indirect impact of COVID-19 pandemic-related mobility restrictions on the uptake of diagnostic tests for HIV and syphilis and the potential adoption of targeted-testing strategies. Understanding the extent and complexity of COVID-19 aftermaths on specific conditions and communities is essential to build strategies to mitigate the long-term consequences of COVID-19.

COVID-19-associated aspergillosis in a Brazilian referral centre: Diagnosis, risk factors and outcomes.

BACKGROUND: COVID-19 patients on mechanical ventilation are at risk to develop invasive aspergillosis. To provide additional data regarding this intriguing entity, we conducted a retrospective study describing risk factors, radiology and prognosis of this emerging entity in a Brazilian referral centre. METHODS: This retrospective study included intubated (≥18 years) patients with COVID-19 admitted from April 2020 until July 2021 that had bronchoscopy to investigate pulmonary co-infections. COVID-19-associated aspergillosis (CAPA) was defined according to the 2020 European Confederation of Medical Mycology/International Society of Human and Animal Mycosis consensus criteria. The performance of tracheal aspirate (TA) cultures to diagnose CAPA were described, as well as the radiological findings, risk factors and outcomes. RESULTS: Fourteen patients (14/87, 16%) had probable CAPA (0.9 cases per 100 ICU admissions). The sensitivity, specificity, positive predictive value and negative predictive value of TA for the diagnosis of CAPA were 85.7%, 73.1%, 46.2% and 95% respectively. Most of the radiological findings of CAPA were classified as typical of invasive pulmonary aspergillosis (64.3%). The overall mortality rate of probable CAPA was 71.4%. Age was the only independent risk factor for CAPA [p = .03; odds ratio (OR) 1.072]. CAPA patients under renal replacement therapy (RRT) may have a higher risk for a fatal outcome (p = .053, hazard ratio 8.047). CONCLUSIONS: CAPA was a prevalent co-infection in our cohort of patients under mechanical ventilation. Older patients had a higher risk to develop CAPA, and a poor prognosis may be associated with RRT.

Next-generation sequencing (NGS) to determine microbiome of herniated intervertebral disc.

BACKGROUND CONTEXT: There is apparent causality between chronic infection of the intervertebral disc and its degenerative process. Although disc is considered a sterile tissue, collected samples of uninfected patients sent to culture testing resulted positive. PURPOSE: The purpose of this study was to analyze the microbiome of the intervertebral disc by using and validating the next-generation sequencing (NGS) molecular test, controlled with tissue culture and clinical presentation of patients. STUDY DESIGN/SETTING: Prospective study of consecutive patients in a hospital. PATIENT SAMPLE: Patients with lumbar disc herniation undergoing open microdiscectomy aging 18 to 65 years. OUTCOME MEASURES: NGS, tissue culture METHODS: Subjects undergoing open decompression surgery for lumbar disc herniation were consecutively included and clinically followed for one year. Three samples of the excised herniated disc fragment were sent to tissue culture and another sample of the disc was sent to NGS test for microbiome analysis. Control samples of the ligamentum flavum and deep muscle were collected and sent to culture. RESULTS: A total of 17 patients were included. All patients presented negative cultures of the removed disc samples, as well as negative cultures of muscle and yellow ligament. None of the patients evolved to clinical infection one year after surgery, nor presented significant alteration of laboratory markers. NGS mapped a mean of 14,645 (range 6,540 to 27,176) DNA sequences for each disc sample of each patient. There were a total of 45 different bacteria genera remnants with different amount of DNA sequences detected. There was a mean of 8 (range 3-17) different bacterial elements in each sample of intervertebral disc. Three bacteria were present in all disc samples (Herbaspirillum, Ralstonia, and Burkolderia). Although there were a considerable mean number of bacterial sequences mapped in each disc sample, the amount of sequences related to bacteria was low. Cutibacterium acnes elements was not found in any disc microbiome analysis. CONCLUSIONS: NGS has been proven to adequately determine bacterial DNA presence within the intervertebral disc. C. acnes was not isolated in culture neither in microbiome analysis of patients with lumbar disc herniation. We cannot confirm disc sterility since, even if it does not cause infection, there is bacterial or remnant DNA in herniated discs.

Real-life occurrence of bacterial sexually transmitted infections among PrEP users: improving the diagnosis of Chlamydia trachomatis and Neisseria gonorrhoeae with multisite screening.

PrEP users are under high risk for bacterial sexually transmitted infections (STI), including those caused by Treponema pallidum (Tp), Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng). Ct and Ng screening at multiple anatomic sites may improve the diagnostic sensitivity among high-risk populations. We analyzed the prevalence and incidence of Ct, Ng, and Tp and investigated predictors of bacterial STI occurrence between January 2018 and November 2019 in a retrospective cohort of PrEP users in Sao Paulo, Brazil. We describe the frequency and percentage of Ct/Ng per anatomical site and calculate the percentage of missed diagnosis if molecular testing were applied only in symptomatic patients, or only in urine samples. Patients underwent syphilis testing every 3-4 months and Ct/Ng testing every 6 months. We included 413 PrEP users with a median age of 31 years. At baseline, 25% had a positive treponemal test and 7% had active syphilis; Ct and Ng were more frequently detected in the oropharynx and anus (6.4-6.9%) than in urine samples (0.7-2.6%). Twelve months after the onset of PrEP, the incidence of Tp, Ct and Ng was, respectively, 13.4%, 11.4% and 8.9%. During follow-up, 23 out of 33 Ct/Ng cases (69%, 95% CI 51-84) would have been missed if oropharynx and anus samples had not been tested. In addition, if only symptomatic cases had been tested, 30 out of 33 Ct/Ng cases (90%, 95% CI 75-98) would have been missed. Participants with incident STI had a higher baseline number of sexual partners and a longer follow-up. Our study reinforces that active and frequent screening for STI is a powerful strategy to improve the diagnostic sensitivity.

Prevalence of blaKPC-2, blaKPC-3 and blaKPC-30-Carrying Plasmids in Klebsiella pneumoniae Isolated in a Brazilian Hospital.

Klebsiella pneumoniae carbapenemase (KPC) actively hydrolyzes carbapenems, antibiotics often used a last-line treatment for multidrug-resistant bacteria. KPC clinical relevance resides in its widespread dissemination. In this work, we report the genomic context of KPC coding genes blaKPC-2, blaKPC-3 and blaKPC-30 in multidrug-resistant Klebsiellapneumoniae isolates from Brazil. Plasmids harboring blaKPC-3 and blaKPC-30 were identified. Fifteen additional carbapenem-resistant K. pneumoniae isolates were selected from the same tertiary hospital, collected over a period of 8 years. Their genomes were sequenced in order to evaluate the prevalence and dissemination of blaKPC-harboring plasmids. We found that blaKPC genes were mostly carried by one of two isoforms of transposon Tn4401 (Tn4401a or Tn4401b) that were predominantly located on plasmids highly similar to the previously described plasmid pKPC_FCF3SP (IncN). The identified pKPC_FCF3SP-like plasmids carried either blaKPC-2 or blaKPC-30. Two K. pneumoniae isolates harbored pKpQIL-like (IncFII) plasmids, only recently identified in Brazil; one of them harbored blaKPC-3 in a Tn4401a transposon. Underlining the risk of horizontal spread of KPC coding genes, this study reports the prevalence of blaKPC-2 and the recent spread of blaKPC-3, and blaKPC-30, in association with different isoforms of Tn4401, together with high synteny of plasmid backbones among isolates studied here and in comparison with previous reports.

Clostridioides difficile laboratory diagnostic techniques: a comparative approach of rapid and molecular methods.

Clostridioides difficile infection is a public health problem because of it is easily spread; with harmful consequences, it is essential to reduce hospital costs and prevent its dissemination by having a precise diagnosis. The gold standard for its diagnosis is polymerase chain reaction (PCR); however, the technique is not available for all laboratories due to the high cost. New approaches using non-molecular tests to detect C. difficile and toxin A/B production has been proposed to improve cost benefits. The objective of this study is to compare molecular methods (PCR) and rapid methods (immunochromatographic test and enzymatic immunoassay). A series of tests comprising these diagnostic techniques was performed with 50 patients with a clinical diagnosis for Clostridioides difficile on GeneXpert® devices test; a calculation of the sensitivity was executed, followed by a comparison of the efficiency of all techniques. Greater sensitivity was observed in the PCR-based methods (BD MAX™ and BioFire FilmArray®) and the GDH-based assays (RIDASCREEN® and Alere Techlab®). The proposed algorithm represents minor monetary disadvantages but a significant temporal optimization of 10%. Future studies concerning both positive and negative results could be advantageous because of the possibility of calculating more method concordance indexes, such as the specificity and Kappa index, in addition to being able to indicate a monetary profit if the proposed algorithm was applied due to the nonproceeding PCR cases.

Usefulness of aqueous and vitreous humor analysis in infectious uveitis.

OBJECTIVE: To evaluate the role of intraocular fluid analysis as a diagnostic aid for uveitis. METHODS: Twenty-eight samples (27 patients including 3 HIV-infected patients) with active (n=24) or non-active (n=4) uveitis were submitted to aqueous (AH; n=12) or vitreous humor (VH) analysis (n=16). All samples were analyzed by quantitative PCR for herpes simplex virus (HSV), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV) and Toxoplasma gondii. RESULTS: The positivity of the PCR in AH was 41.7% (5/12), with 50% (2/4) in immunocompetent and 67% (2/3) in HIV+ patients. The positivity of the PCR in VH was 31.2% (5/16), with 13% (1/8) in immunocompetent and 50% (4/8) in immunosuppressed HIV negative patients. The analysis was a determinant in the diagnostic definition in 58% of HA and 50% of VH. CONCLUSION: Even in posterior uveitis, initial AH analysis may be helpful. A careful formulation of possible clinical diagnosis seems to increase the chance of intraocular sample analysis being meaningful.

Usefulness of aqueous and vitreous humor analysis in infectious uveitis

OBJECTIVE: To evaluate the role of intraocular fluid analysis as a diagnostic aid for uveitis. METHODS: Twenty-eight samples (27 patients including 3 HIV-infected patients) with active (n=24) or non-active (n=4) uveitis were submitted to aqueous (AH; n=12) or vitreous humor (VH) analysis (n=16). All samples were analyzed by quantitative PCR for herpes simplex virus (HSV), varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV) and Toxoplasma gondii. RESULTS: The positivity of the PCR in AH was 41.7% (5/12), with 50% (2/4) in immunocompetent and 67% (2/3) in HIV+ patients. The positivity of the PCR in VH was 31.2% (5/16), with 13% (1/8) in immunocompetent and 50% (4/8) in immunosuppressed HIV negative patients. The analysis was a determinant in the diagnostic definition in 58% of HA and 50% of VH. CONCLUSION: Even in posterior uveitis, initial AH analysis may be helpful. A careful formulation of possible clinical diagnosis seems to increase the chance of intraocular sample analysis being meaningful.

Temporal evolution of antimicrobial resistance among Neisseria gonorrhoeae clinical isolates in the most populated South American Metropolitan Region.

A total of 124 Neisseria gonorrhoeae isolates recovered during a 12-year period (2003-2015) from outpatients assisted at Centro de Referência e Treinamento DST/AIDS-CRT of São Paulo city, Brazil, were analysed. The following resistance rates were observed: penicillin-59.6%, ciprofloxacin-15.3%, and azithromycin-6.7%. Although reduced susceptibility to these drugs was observed since 2003, no ceftriaxone-resistant isolates were detected. Ciprofloxacin- and azithromycin non-susceptible isolates were grouped in 11 clusters. Mutations were detected in GyrA and ParC of isolates 124 and 260, and a C2611T substitution on 23S rRNA alleles was also observed in isolate 260. Both isolates belonged to ST1901/ST6210 (MSLT/NG-MAST schemes).

Temporal evolution of antimicrobial resistance among Neisseria gonorrhoeae clinical isolates in the most populated South American Metropolitan Region

A total of 124 Neisseria gonorrhoeae isolates recovered during a 12-year period (2003-2015) from outpatients assisted at Centro de Referência e Treinamento DST/AIDS-CRT of São Paulo city, Brazil, were analysed. The following resistance rates were observed: penicillin-59.6%, ciprofloxacin-15.3%, and azithromycin-6.7%. Although reduced susceptibility to these drugs was observed since 2003, no ceftriaxone-resistant isolates were detected. Ciprofloxacin- and azithromycin non-susceptible isolates were grouped in 11 clusters. Mutations were detected in GyrA and ParC of isolates 124 and 260, and a C2611T substitution on 23S rRNA alleles was also observed in isolate 260. Both isolates belonged to ST1901/ST6210 (MSLT/NG-MAST schemes).

Comparative Genomics of Nonoutbreak Pseudomonas aeruginosa Strains Underlines Genome Plasticity and Geographic Relatedness of the Global Clone ST235.

Pseudomonas aeruginosa is an important opportunistic pathogen in hospitals, responsible for various infections that are difficult to treat due to intrinsic and acquired antibiotic resistance. Here, 20 epidemiologically unrelated strains isolated from patients in a general hospital over a time period of two decades were analyzed using whole genome sequencing. The genomes were compared in order to assess the presence of a predominant clone or sequence type (ST). No clonal structure was identified, but core genome-based single nucleotide polymorphism (SNP) analysis distinguished two major, previously identified phylogenetic groups. Interestingly, most of the older strains isolated between 1994 and 1998 harbored exoU, encoding a cytotoxic phospholipase. In contrast, most strains isolated between 2011 and 2016 were exoU-negative and phylogenetically very distinct from the older strains, suggesting a population shift of nosocomial P. aeruginosa over time. Three out of 20 strains were ST235 strains, a global high-risk clonal lineage; these carried several additional resistance determinants including aac(6')Ib-cr encoding an aminoglycoside N-acetyltransferase that confers resistance to fluoroquinolones. Core genome comparison with ST235 strains from other parts of the world showed that the three strains clustered together with other Brazilian/Argentinean isolates. Despite this regional relatedness, the individuality of each of the three ST235 strains was revealed by core genome-based SNPs and the presence of genomic islands in the accessory genome. Similarly, strain-specific characteristics were detected for the remaining strains, indicative of individual evolutionary histories and elevated genome plasticity.

Evaluation of two commercial methods for the susceptibility testing of Candida species: Vitek 2(R) and Sensititre YeastOne(R) / Evaluación de dos métodos comerciales para el estudio de la sensibilidad a los antifúngicos de especies de Candida: Vitek 2(R) y Sensititre YeastOne(R)

Background: An increased incidence of fungal infections caused by Candida species, especially Candida glabrata and Candida krusei, which are less susceptible to azoles, has been observed. Standardized susceptibility testing is essential for clinical management and for monitoring the epidemiology of resistance. Aims: We evaluated the performance of two different susceptibility testing commercial methods, Vitek 2(R) and Sensititre YeastOne(R), and compared them with the standard broth microdilution method (CLSI). Methods: A total of 80 isolates of several Candida species (Candida albicans, Candida parapsilosis complex, Candida tropicalis, C. glabrata and C. krusei) were selected for this study. Results: We analyzed the categorical agreement (CA) between the methods, stratifying the disagreements. The average CA between the methods was 96.3% for Vitek 2(R) and 84% for Sensititre YeastOne(R). No very major errors were observed. Major errors and minor errors were found for all the isolates tested. With the azoles, both Vitek 2(R) and Sensititre YeastOne(R) had good and similar performance levels, except for C. tropicalis and C. krusei (Sensititre YeastOne(R) showed low CA, 56.2%). With the echinocandins, both methods showed good performance for C. albicans, C. parapsilosis and C. tropicalis. However, we observed important discrepancies for C. krusei with caspofungin: Vitek 2(R) had 100% CA while Sensititre YeastOne(R) had only 25%. With amphotericin B, both Vitek 2(R) and Sensititre YeastOne(R) had good performance with high CA. Conclusions: Despite the limited isolates tested, we concluded that both methods have good performance and are reliable for antifungal susceptibility testing. However, caspofungin activity against C. krusei and C. glabrata should be interpreted carefully when using Sensititre YeastOne(R) because we observed a low CA

Antecedentes: La incidencia de infecciones fúngicas provocadas por especies de Candida, especialmente por Candida glabrata y Candida krusei, menos sensibles a los azoles, ha ido en aumento. Los métodos estandarizados de estudio de la sensibilidad a los antifúngicos son fundamentales para el manejo clínico y para un mejor seguimiento de la epidemiología de la resistencia. Objetivos: Se evaluó la actividad de dos métodos comerciales diferentes para el estudio de la sensibilidad in vitro a los antifúngicos, Vitek 2(R) y Sensititre YeastOne(R), y se compararon con la técnica estándar de microdilución en caldo del CLSI. Métodos: Para este estudio se seleccionó un total de 80 cepas aisladas de varias especies de Candida (Candida albicans, Candida parapsilosis, Candida tropicalis, C. glabrata y C. krusei). Resultados: Se analizó la concordancia categórica (CC) entre los métodos y se estratificaron los desacuerdos. La CC media entre los métodos fue del 96,3% para Vitek 2(R) y del 84% para Sensititre YeastOne(R). No se observaron errores muy altos. Se encontraron errores mayores y menores en todos los aislamientos probados. Con los azoles, tanto Vitek 2(R) como YeastOne(R) presentaron rendimientos buenos y similares, excepto para C. tropicalis y C. krusei (Sensititre YeastOne(R) mostró baja CC, el 56,2%). Con las equinocandinas, los dos métodos mostraron buen rendimiento para C. albicans, C. parapsilosis y C. tropicalis. Sin embargo, se observaron discrepancias importantes para C. krusei con la caspofungina: Vitek 2(R) presentó el 100% de CC, mientras que Sensititre YeastOne(R) solo el 25%. Para la anfotericina B, Vitek 2(R) y Sensititre YeastOne(R) presentaron un buen rendimiento con una CC alta. Conclusiones: Aunque el número de cepas aisladas probadas fue limitado, concluimos que los dos métodos tienen un buen rendimiento y son fiables para la prueba de sensibilidad antifúngica. Sin embargo, la actividad de la caspofungina frente a C. krusei y C. glabrata mediante el método Sensititre YeastOne(R) debe interpretarse cuidadosamente, ya que se observa un valor bajo de CC

Evaluation of two commercial methods for the susceptibility testing of Candida species: Vitek 2® and Sensititre YeastOne®.

BACKGROUND: An increased incidence of fungal infections caused by Candida species, especially Candida glabrata and Candida krusei, which are less susceptible to azoles, has been observed. Standardized susceptibility testing is essential for clinical management and for monitoring the epidemiology of resistance. AIMS: We evaluated the performance of two different susceptibility testing commercial methods, Vitek 2® and Sensititre YeastOne®, and compared them with the standard broth microdilution method (CLSI). METHODS: A total of 80 isolates of several Candida species (Candida albicans, Candida parapsilosis complex, Candida tropicalis, C. glabrata and C. krusei) were selected for this study. RESULTS: We analyzed the categorical agreement (CA) between the methods, stratifying the disagreements. The average CA between the methods was 96.3% for Vitek 2® and 84% for Sensititre YeastOne®. No very major errors were observed. Major errors and minor errors were found for all the isolates tested. With the azoles, both Vitek 2® and Sensititre YeastOne® had good and similar performance levels, except for C. tropicalis and C. krusei (Sensititre YeastOne® showed low CA, 56.2%). With the echinocandins, both methods showed good performance for C. albicans, C. parapsilosis and C. tropicalis. However, we observed important discrepancies for C. krusei with caspofungin: Vitek 2® had 100% CA while Sensititre YeastOne® had only 25%. With amphotericin B, both Vitek 2® and Sensititre YeastOne® had good performance with high CA. CONCLUSIONS: Despite the limited isolates tested, we concluded that both methods have good performance and are reliable for antifungal susceptibility testing. However, caspofungin activity against C. krusei and C. glabrata should be interpreted carefully when using Sensititre YeastOne® because we observed a low CA.