Discordancia entre pruebas de susceptibilidad genotípicas y fenotípicas para tuberculosis en Cali, Colombia: un reto en la práctica clínica

Introducción: La detección de patrones de resistencia de Mycobacterium tuberculosis se basa en pruebas de susceptibilidad fenotípicas y genotípicas. Los resultados discordantes entre ellas son un desafío clínico para el manejo de pacientes con tuberculosis resistente a fármacos. Objetivo: Evaluar la concordancia entre pruebas fenotípicas y moleculares en pacientes con tuberculosis resistente a fármacos atendidos en una institución de Cali, Colombia. Materiales y Métodos: Se realizó un estudio transversal en el que se obtuvo el perfil de sensibilidad fenotípico de cultivos de micobacterias y la susceptibilidad genotípica con las pruebas moleculares Xpert-MTB/ RIF® o Genotype-MDRTBplus ®. Se evaluó el porcentaje de resistencia y porcentaje de acuerdo entre los resultados de las pruebas fenotípicas y genotípicas. Se estimó un coeficiente de kappa de Cohen (κ) para cada tipo de resistencia según la prueba utilizada. Resultados: Se incluyeron 30 casos con resultados de pruebas genotípicas y fenotípicas. Las pruebas fenotípicas detectaron resistencia a fármacos de primera línea en 29/30 casos, mientras que las moleculares detectaron la resistencia en todos los casos evaluados. El porcentaje de resistencia a rifampicina detectado entre la prueba fenotípica y Genotype-MDRTBplus ® &e 61,5% (acuerdo global 41,1%, κ = 0,40, p = 0,96), mientras que el porcentaje de resistencia detectado con Xpert-MTB/RIF® fue 100% (acuerdo global 81,82%, κ: 0,00, p < 0,001) para este mismo medicamento. El porcentaje de resistencia a isoniacida detectado entre la prueba fenotípica y Genotype-MDRTBplus ® fue 94,4% (acuerdo global 89,47%, κ: -0,055 p = 0,59). Conclusiones: La discordancia entre los resultados de las pruebas genotípicas y fenotípicas es posible, por lo que es importante usar e interpretar ambos tipos de pruebas de manera complementaria en el diagnóstico de la resistencia a fármacos de primera línea en la infección por M. tuberculosis.

Background: The detection of Mycobacterium tuberculosis resistance patterns is based on phenotypic and genotypic susceptibility tests. The discordant results between them are a clinical challenge for the management of patients with drug-resistant tuberculosis. Aim: To evaluate the concordance between phenotypic and molecular tests in patients with drug-resistant tuberculosis treated in an institution in Cali, Colombia. Methods: A cross-sectional study was conducted. A phenotypic sensitivity profile was obtained from mycobacterial cultures. The genotypic susceptibility was obtained with Xpert-MTB/ RIF® or Genotype-MDRTBplus ®. The percentage of resistance and percentage of agreement between the results of the phenotypic and genotypic tests were evaluated. A Cohen's kappa coefficient (κ) was estimated for each type of resistance according to the test used. Results: A total of 30 cases with both genotypic and phenotypic testing were included. The phenotypic tests detected resistance to first-line drugs in 29/30 cases, while the molecular tests detected resistance in all the cases evaluated. The percentage of resistance detected between Genotype-MDRTBplus® and the phenotypic test for rifampicin was 61.5% (overall agreement 41.1%, κ = 0.40, p = 0.96), while the percentage of resistance detected with XpertMTB/RIF® was 100% (overall agreement 81.82%, κ: 0.00, p < 0.001) for this same drug. Resistance to isoniazid detected by both types of tests was 94.4% (overall agreement 89.47%, κ: -0.055 p = 0.59). Conclusions: Discordance between the results of genotypic and phenotypic tests is possible, so it is important to use and interpret both types of tests in a complementary way in the diagnosis of resistance to first-line drugs in M. tuberculosis infection.

Assessment of rifampicin resistance in re-treatment cases of pulmonary tuberculosis using gene-xpert

Objective:To assess therifampicin resistance in re-treatment cases of pulmonary tuberculosis using gene-xpert.Material and methods:This cross sectional study was conducted at Department of Pulmonology Bahawal Victoria Hospital, Bahawalpur.Total 145 patients who came for re-treatment of TB either male or female having age 20-60 years were selected for this study.Results:Mean age of the patients was 45.79 ± 11.65 years and mean duration of TB was 5.44 ± 2.9 years.Rifampicin resistance was found in 55 (38%) cases by using gene-xpert test. Rifampicin resistance is significantly associated with gender but insignificantly associated with age and duration of TB.Conclusion:In present study very high percentage of rifampicin resistance was found in retreatment cases of TB by using gen-xpert test.Significant association of gender with rifampicin resistance was noted but insignificant association of age and duration of TB with rifampicin resistance was detected.

Evaluation of Pathogens Causing Urinary Tract Infection and Their Sensitivity Pattern

Background: UTI constitute a major public health problem in India accounting 2nd most common infection next to respiratory tract infection. They are responsible for increasing treatment cost and significant morbidity.Aim:-To determine the incidence of UTI, evaluation of pathogens responsible and their antimicrobial susceptibility pattern in the population.Methods:Urine samples were collected from 300 patients attending the OPD Patna medical college, Patna during the period of 18 months (January 2017 to June 2018) Antimicrobial sensitivity testing was done for the bacterial isolates present in the sample by Kirby- Bauer disc diffusion method. Only those samples were taken into consideration which develops count equal to or greater than 1*105CFU/ml as indicated by Kass.Results:Out of 300 samples collected 146 (48.66%)) yielded bacterial growth. Out of 146 culture isolates E.Coli was the most common pathogen followed by klebsiella, CoNS and staphylococcus. Antibiotic sensitivity was performed on all the isolates. It was observed that highest sensitivity was 49.31% to amikacin, gentamycin (45.89%), nitrofurantoin (38.35%) meropenem (27.39%).Conclusions:It was observed that high grade of resistance to ampicillin, cotrimoxazole, ciprofloxacin, cefuroxime, chloramphenicol, cefotaxime, cefazolin, amoxicillin + clavulanic acid and gentamycin is present as a result of misuse or improper use of antibiotic in the community. Hence urine culture is necessary for the diagnostic screening of UTI before the treatment.

Species distribution and antifungal susceptibility to vulvovaginal Candida spp. in southern Mato Grosso State, Brazil / Distribuição de espécies e suscetibilidade a antifúngicos de Candida spp. vulvovaginais no sul de Mato Grosso, Brasil

ABSTRACT INTRODUCTION: Vulvovaginal candidiasis is a prevalent opportunistic mucosal infection, caused predominantly by Candida albicans. Candida species vary in their susceptibility to the antifungal agents, thus, the susceptibility tests have clinical significance in determining the appropriate therapeutic choice. OBJECTIVE: To investigate the distribution of vulvovaginal yeasts and the susceptibility pattern to azoles antifungal isolated in southern Mato Grosso State, Brazil. MATERIAL AND METHODS: Clinical samples from 166 patients were obtained regardless signs and symptoms of vulvovaginal candidiasis. Vaginal swabs were collected, seeded onto plates containing Sabouraud Dextrose agar and incubated at 35ºC, for five days. A pool of colonies that grown on each plate was subcultured in CHROMagar Candida medium. On the basis of a pure culture, the yeasts were identified using traditional phenotypic identification methods. Susceptibility tests for antifungal fluconazole and ketoconazole were performed using the broth microdilution method according to the reference protocol M27A3 of the Clinical Laboratory Standards Institute (CLSI). RESULTS: The frequency of Candida spp. in the study population was 30%, of which 28% were in the group of asymptomatic women and 35% among symptomatic. Among the isolated strains were C. albicans (50%), C. glabrata (33%) and C. tropicalis (17%). The minimum inhibitory concentration (MIC) for fluconazole ranged from 0.5 μg/ml to 16 μg/ml and for ketoconazole from 0.03 μg/ml to 4 μg/ml. The resistance rates were 1.7% for fluconazole and 3.4% for ketoconazole. CONCLUSION: C. albicans was the predominant species. We observed a high susceptibility of Candida spp. to fluconazole and ketoconazole antifungal.

RESUMO INTRODUÇÃO: A candidíase vulvovaginal é uma prevalente infeccção mucosa oportunista, causada predominantemente por Candida albicans. As espéceis de Candida variam de acordo com a suscetibilidade aos agentes antifúngicos, assim os testes de sensibilidade têm importância clínica para uma adequada escolha terapêutica. OBJETIVO: Investigar a distribuição de leveduras vulvovaginais e o padrão de suscetibilidade a antifúngicos azólicos em isolados do sul de Mato Grosso. MATERIAL E MÉTODOS: Foram obtidas amostras clínicas de 166 pacientes, independentemente de sinais e sintomas para candidíase vulvovaginal. Swabs vaginais foram coletados, semeados em placas contendo ágar Sabouraud e incubados a 35ºC. Uma amostra das colônias que cresceram em cada placa foi subcultivada em meio CHROMagar Candida. Partindo de uma cultura pura, as leveduras foram identificadas por métodos fenotípicos clássicos. Os testes de suscetibilidade aos antifúngicos cetoconazol e fluconazol foram realizados, usando o método de microdiluição de acordo com o protocolo de referência M27A3 do Clinical Laboratory Standards Institute (CLSI). RESULTADOS: A frequência de Candida spp. na população em estudo foi de 30%, sendo 28% no grupo de mulheres assintomáticas e 35% entre as sintomáticas. As espécies isoladas foram C. albicans (50%), C. glabrata (33%) e C. tropicalis (17%). A concentração inibitória mínima (CIM) para o fluconazol variou de 0,5 μg/ml a 16 μg/ml e para o cetoconazol, de 0,03 μg/ml a 4 μg/ml. A frequência de resistência ao fluconazol foi de 1,7% e ao cetoconazol, de 3,4%. CONCLUSÃO: C. albicans foi a espécie predominante. Observamos elevada sensibilidade de Candida spp. aos antifúngicos fluconazol e cetoconazol.

Epidemiología de la candidemia y sensibilidad in vitro frente a azoles, anfotericina B y caspofungina en una institución de salud de Valledupar, Colombia / Epidemiology of candidemia and in vitro susceptibility to azoles, amphotericin B and caspofungin in a health institution of Valledupar, Colombia

Introducción: la candidemia es una enfermedad grave, con elevada morbi-mortalidad y cuyo tratamientono siempre conduce a la cura. La distribución de especies de Candida y la sensibilidad antifúngica varía según el área geográfica, incluso entre centros de salud de una misma región. Objetivo:establecer la distribución de especies de Candida y su sensibilidad in vitro frente a diferentes antifúngicos. Materiales y métodos: se realizó un estudio descriptivo, prospectivo y transversal entre noviembre de 2013 y mayo de 2014 de casos de candidemias en una institución de salud de Valledupar,Colombia. Las Concentraciones Inhibitorias Mínimas (CIM) se determinaron según el protocolo estándar M27-A3-S4. Resultados: Se estudiaron 40 aislados clínicos de Candida spp. obtenidos de sangre (97,5%) y médula ósea (2,5%). Del total, 15 (37,5%) fueron caracterizados como Candida tropicalis, 13 (32,5%) del Complejo Candida albicans, cinco (12,5%) del Complejo Candida glabrata, tres (7,5%) como Candida guilliermondii, tres (7,5%) del Complejo Candida parapsilosis y uno (2,5%) como Candida krusei. No se observó resistencia a la anfotericina B ni al voriconazol en ninguno de los aislados, pero sí al fluconazol en uno (6,6%) de Candida tropicalis y uno (33,3%) del Complejo Candida parapsilosis y a la caspofungina en el aislado de Candida krusei y en uno (20%) del Complejo Candida glabrata...

Introduction: candidemia is a serious disease with high morbidity and mortality whose treatment does not always lead to a cure. Candida species distribution and antifungal susceptibility varies by geographic area, even in health centers in a given region. Objective: To establish Candida species distributionand in vitro susceptibility to different antifungal agents. Material and methods: A descriptive, prospective, and cross-sectional study of candidemia cases was performed at a health institution in Valledupar, Colombia between November 2013 and May 2014. The Minimum Inhibitory Concentrations(MIC) were determined following the M27-A3-S4 standard protocol. Results: 40 isolates of Candida spp. obtained from blood (97.5%) and bone marrow (2.5%) were analyzed. Candida tropicalis, 15 (37.5%), Candida albicans Complex, 13 (32.5%), Candida glabrata Complex, five (12.5%), Candida guilliermondii, three (7.5%), Candida parapsilosis Complex 3 (7.5%) and Candida krusei, one (2.5%) were isolated. No resistance of isolates to amphotericin B and voriconazole was observed; in contrast, one (6.6%) isolate of Candida tropicalis and one (33.3%) of Candida parapsilosisComplex showed resistance to fluconazole and a single isolate of Candida krusei and one (20%) of Candida glabrata Complex to caspofungin...

Acinetobacter baumannii: importancia clínica, mecanismos de resistencia y diagnóstico / Acinetobacter baumannii: Clinical importance, resistance mechanisms and diagnosis

Acinetobacter baumannii ha emergido como una bacteria de gran importancia clínica. Esta bacteria ha sido relacionada con altos porcentajes de mortalidad y posee una alta capacidad para diseminarse en el ambiente hospitalario. Con el paso del tiempo, Acinetobacter baumannii ha adquirido diferentes mecanismos de resistencia a los antibióticos y en la actualidad se reporta resistencia a carbapenémicos, aminoglicósidos, quinolonas y polimixinas, lo que ha complicado el manejo de las infecciones ocasionadas por esta bacteria. El problema se agrava aún más con las limitaciones en el diagnóstico y la carencia de métodos fenotípicos estandarizados que permitan detectar los mecanismos de resistencia específicos. En Colombia se han descrito altos porcentajes de resistencia a los carbapenémicos, lo que ha limitado las opciones terapéuticas y hace necesario el conocimiento de la epidemiología local para establecer medidas de control más certeras.

Currently Acinetobacter baumannii has become in a microorganisms of great clinical importance. It has an extraordinary capacity to spread in the hospital environment and it has been associated with high mortality rates. Acinetobacter baumannii has acquired different resistance mechanisms to antibiotics with reports resistance to carbapenems, aminoglycosides, quinolones and polymyxins; which has complicated the therapy of the infections caused for this pathogen. The problem is further due to the limitations in the diagnosis and the lack of standardized phenotypic methods to detect specific resistance mechanisms. In Colombia has reported high percentages of resistance to carbapenems, which has reduced therapeutic options. The knowledge of local epidemiology is necessary for establish more assertive control measures.

Susceptibilidad in vitro a cinco antifúngicos de aislamientos del Complejo Fusarium solani provenientes de úlceras corneales / In vitro susceptibility to five antifungals of Fusarium solani Complex isolates obtained from corneal ulcers

El Complejo Fusarium solani (CFS) se encuentra distribuido en la naturaleza, causando un amplio espectro de infecciones en los humanos, desde superficiales, como la queratitis, hasta infecciones fúngicas invasoras, caracterizándose por su resistencia a los antimicóticos. El objetivo de esta investigación fue determinar la susceptibilidad in vitro del CFS frente a cinco antifúngicos. Se utilizaron 30 aislados obtenidos de úlceras corneales provenientes de la colección de cultivos del Departamento de Micología del Instituto Nacional de Higiene “Rafael Rangel” y se siguió el protocolo descrito en el documento M38-A2 del Instituto de Estándares Clínicos y de Laboratorio (CLSI), determinando las Concentraciones Mínimas Inhibitorias (CMI) por microdilución en caldo para anfotericina B, itraconazol, posaconazol, voriconazol y fluconazol. En general, todas las drogas presentaron CMI elevadas, siendo voriconazol y anfotericina B los antifúngicos que exhibieron mejor actividad, mientras que itraconazol, posaconazol y fluconazol mostraron actividad nula. Los resultados de este estudio aportaron información importante sobre el comportamiento del CFS frente a los antifúngicos de uso común en la práctica clínica por primera vez en Venezuela. Es imprescindible que el médico conozca la actividad de estas drogas para poder tomar decisiones y orientar una conducta terapéutica adecuada.

The Fusarium solani Complex (FSC) is distributed in nature, producing a wide spectrum of infections in humans, from superficial ones such as keratitis, to invasive fungal infections, characterized by their resistance to antimycotics. The purpose of this investigation was to determine the in vitro susceptibility of the FSC to five antifungals. We used 30 isolates obtained from corneal ulcers kept at the culture collection of the Instituto Nacional de Higiene “Rafael Rangel” and we followed the protocol described in the M38-A2 document of the Clinical and Laboratory Standards Institute (CLSI) determining the Minimal Inhibitory Concentrations (MIC) by broth microdilution for amphotericin B, itraconazole, posaconazole, voriconazole and fluconazole. In general, all the drugs presented high MICs, voriconazole and amphotericin B being the antifungals which showed the best activity, while itraconazole, posaconazole and fluconazole showed a null activity. The results of this study provided, for the first time in Venezuela, important information about the behavior of the FSC towards commonly used antifungals. It is mandatory that physicians know the activity of these drugs in order to be able to take decisions and devise an guide an appropriate therapeutic management.

Validación del inóculo por densitometría para las pruebas de susceptibilidad a los antifúngicos en especies del género Fusarium / Validation of the inoculum by densitometry for antifungal susceptibility testing in Fusarium species

El objetivo de este trabajo fue validar la preparación del inóculo por densitometría para las pruebas de susceptibilidad a los antifúngicos en especies del género Fusarium. Se emplearon 15 aislamientos clínicos de Fusarium spp. para preparar los inóculos por espectrofotometría y contaje de unidades formadoras de colonias en cámara de Neubauer, siguiendo los protocolos establecidos por los documentos de referencia M38-A2 del Instituto de Estándares Clínicos y de Laboratorio (CLSI) y E.DEF 9.1 del Comité Europeo para Pruebas de Susceptibilidad a los Antimicrobianos (EUCAST), respectivamente. En paralelo se determinaron las lecturas por densitometría para ambos procedimientos. Se estableció un rango de 0,5-0,7 unidades McFarland para la preparación del inóculo por densitometría según el CLSI, y un rango de 0,2-0,8 unidades McFarland para la metodología descrita por el EUCAST. Con este estudio, se logró validar la preparación del inóculo para las pruebas de susceptibilidad en Fusarium spp., utilizando la densitometría como método alternativo de los procedimientos descritos internacionalmente, con considerables ventajas para ser implementado en los laboratorios de microbiología clínica. La variabilidad en cuanto a la capacidad de esporulación y tamaño de las conidias, sobre todo en especies poco frecuentes de Fusarium, sugiere la necesidad de validar el inóculo por especie.

The purpose of this work was to validate the preparation of the inoculum by densitometry for antifungal susceptibility testing in Fusarium species. Fifteen clinical isolates of Fusarium spp. were used to prepare the inocula by spectrophotometry and counting of colony forming units in a Neubauer chamber, according to the protocols established by the reference documents M38-A2 of the Clinical and Laboratory Standards Institute (CLSI), and E.DEF 9.1 of the European Committee on Antimicrobial Susceptibility Testing (EUCAST), respectively. Densitometry readings were determined in parallel for both procedures. A range of 0.5-0.7 McFarland units was established for inocula preparation by densitometry according to the CLSI, and a range of 0.2-0.8 McFarland units was established for the methodology described by EUCAST. This study allowed validating the preparation of the inocula for antifungal susceptibility testing in Fusarium spp., using densitometry as an alternative method for other procedures described internationally, with considerable advantages that can be implemented at clinical microbiology laboratories. The variability regarding sporulation capacity and conidia size, especially in less frequent Fusarium species, suggests the need of validating inocula per species.

Comparison of teicoplanin disk diffusion and broth microdilution methods against clinical isolates of Staphylococcus aureus and S. epidermidis

The CLSI M100-S19 document has recommended the disuse of vancomycin disks for staphylococci and informed that studies on the action of teicoplanin in disk-diffusion testing should be performed. We describe the comparison of two methods, disk diffusion and broth microdilution, for determining teicoplanin susceptibility in clinical isolates of staphylococci. Overall results showed an aggregation rate of 96.8 percent; Staphylococcus aureus showed total agreement while S. epidermidis showed 93.8 percent of agreement. According to these local results, disk diffusion can still be employed to teicoplanin susceptibility determination for staphylococci in our institution.

Estandarización del inóculo por desintometría para las pruebas de susceptibilidad antifungica en especies de fusarium / Inoculum standadization by densitometry for the antifungal susceptibility testing of fusarium species

Las especies del género Fusarium han emergido como patógenos oportunistas en las últimas décadas. La aparición de cepas resistentes y la introducción de nuevos antifúngicos, hace necesaria la realización de las pruebas de susceptibilidad en los laboratorios de microbiología clínica. El objetivo de este estudio fue estandarizar la preparación del inóculo por densitometría para las pruebas de susceptibilidad a los antifúngicos en especies de Fusarium. Se utilizaron 15 aislamientos clínicos de Fusarium spp. y se prepararon los inóculos por espectrofotometría y por contaje de unidades formadoras de conidias en cámara de Neubauer, siguiendo los protocolos establecidos por el CLSI y EUCAST respectivamente, determinando en paralelo sus lecturas por densitometría para ambos procedimientos. Las lecturas densitométricas a través del uso del Densimat®, permitieron establecer un intervalo de 0,5 ­ 0,7 unidades Mc Farland para la preparación del inóculo por la metodología descrita por el CLSI y un rango de 0,2 ­ 0,8 unidades Mc Farland para la metodología según el EUCAST. Con este estudio, pionero en Venezuela, se logró estandarizar la preparación del inóculo óptimo en las pruebas de susceptibilidad para Fusarium spp. utilizando la densitometría como método alternativo, comparable y sustitutivo de los procedimientos descritos internacionalmente, con considerables ventajas (útil, disponible y reproducible) para ser implementado en los laboratorios de microbiología clínica. La variabilidad en cuanto a la capacidad de esporulación y tamaño de las conidias, sobre todo en las especies poco frecuentes de Fusarium, sugiere la necesidad de estandarizar el inóculo por especie.

Fusarium species have emerged like opportunistic pathogens in the last decades. The appearance of new resistant strains and the introduction of new antifungal agents, make necessary susceptibility tests in clinical microbiology laboratories. The objective of this study was to standardize inoculum preparation by densitometry for antifungal susceptibility testing in Fusarium species. Fifteen clinical isolates of Fusarium spp. were used, and the inocula were prepared by spectrophotometry and by conidia forming count in Neubauer chamber, following the establishment protocols of CLSI and EUCAST, respectively, determining in parallel their densitometry readings for both procedures. Densitometry readings by Densimat® allowed to establish an interval of 0.5 - 0.7 Mc Farland units for the inoculum preparation by the CLSI methodology, and a rank of 0.2 - 0.8 Mc Farland units for the methodology according to the EUCAST. With this study, pioneer in Venezuela, it was achieved the standardization of the optimal inoculums preparation for the susceptibility tests in Fusarium spp., using densitometry like an alternative, comparable and substitute method of the described internationally standard procedures, with considerable advantages (useful, available and reproducible) to be applied in clinical microbiology laboratories. The variability as far as both sporulation capability and conidia's size, mainly in less frequent species of Fusarium, suggests the needs to standardize the inoculums by species.

VITEK32 Expert System for Detection and Analysis of Resistance Phenotypes in Commonly Encountered Bacteria:A Clinical Evaluation / 中华医院感染学杂志

OBJECTIVE To evaluate VITEK32 expert system(7.02) for detection and analysis of clinically important resistance phenotypes.METHODS A total of 508 known resistant phenotype clinial strains and 9 standards strains were tested by VITEK32 expert system(7.02) and antibiotic susceptibilities were determined by CLSI recommendation.RESULTS The correct phenotype was identified by the expert system in one or more choices for 312 from the 508(61.4%) isolates and standards.The resistant phenotypes for meticillin-susceptible,and resistant Staphylococcus spp,extended-spectrum ?-lactamases(ESBLs) producingEscherichia coli,Klebsiella spp,AmpC producing Enterobacter,cloacae,Serratia marcescens,and vancomycin-resistant Enterococcus faecalis were accurately identified by VITEK32 expert system,this expert system was not including ESBLs producing Proteus mirabilis.CONCLUSIONS VITEK32 expert system can be accurately identified most clinically important bacteria based on phenotype.The data of ESBLs Producing P.mirabilis should be included in the further work on expert system.

Effects of not Premixed Bacteria Fluid on Antibiotic Susceptibility Tests of VITEK2 Compact / 中华医院感染学杂志

0.05. CONCLUSIONS Not premixed bacteria fluid groups don't affect the antibiotic susceptibility test of VITEK2 Compact.

In vitro antifungal susceptibility of 80 Cryptococcus neoformans isolates / 中华传染病杂志

Objective To determine in vitro drug susceptibility to five antifungal agents of clinical Cryptococcus neoformans strains isolated from different areas of China in recent ten years. Methods Eighty clinical isolates of Cryptococcus neoformans were isolated from Shanghai, Guangdong, Fujian, Beijing and some other areas of China from 1998 to 2007. The minimal inhibitory concentrations (MIC) of the isolates to five antifungal agents, including amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole, were determined using broth microdilution procedure (document M27-A2) recommended by the Clinical and Laboratory Standards Institute (CLSI). Kruskal-Wallis rank sum test was employed for the statistical analysis. Results The MIC50 of the Cryptococcus neoforrnans isolates tested for amphotericin B, fluconazole, flucytosine, itraconazole and voriconazole were 0.5, 4, 2, 0.25 and ≤0.031 3 mg/L, respectively; and the MIC<,90> of the isolates tested for the above antifungal agents were 1, 8, 4, 0.5 and 0.062 5 mg/L, respectively. Among the tested isolates, 3 (3.8 %) were resistant to flucytosine, 4 (5.0 %) were resistant to itraconazole. All isolates were susceptible to amphotericin B and voriconazole. There was no significant difference in MIC of the strains isolated from any particular years to the five agents (χ2=0.500,2.687,2.211, 2.660,0.677,P>0.05). Conclusions The Cryptococcusneoformans isolates are highly susceptible to the five antifungal agents, while a few strains are resistant to flucytosine or itraconazole. The drug susceptibilities of the strains isolated from particular years are similar.

Vibrio vulnificus: cultivation, identification and antimicrobial susceptibility / 中华临床感染病杂志

Objective To investigate the cultivation, biochemical features and drug susceptibilities of Vibrio vulnificus. Methods Three strains of Vibrio vulnificus were isolated from fatal patients in the Second Hospital of Jiaxing, Zhejiang province. Cultivation, identification and antibacterial susceptibility test were performed. Results Vibrio vulnificus grew on blood agar as dull-gray, opaque colonies with β-hemolysis. The organism presented positive in lactose, cellobiose fermentation and O/129 (10 μg) tests, but lack of inositol and rhamnus. The antibacterial susceptibility tests showed that Vibrio vulnificus strains were sensitive to ciprofloxacin, levofloxacin, imipenem, cefepime, ceftazidime, ceftriaxone, compound sulfamethoxazole and nitrofurantoin, however, resistant to gentamicin, tobramycin, aztreonam and cefazolin. Conclusions Vibrio vulnificus can be isolated from blood, bubbles fluid, and stool. Rapid identification, early diagnosis, and prompt empirical antibacterial therapy are important for reducing the mortality.

Antifungal activity of anti-fungi drugs against filamentous fungi in vitro / 中华检验医学杂志

Objective To investigate antifungal activities of AMB, ICZ, VRC, CBF against 72 strains of filamentous fungi in vitro. Methods Based on CLSI M38-P and M38-A scheme, MIC of antifungal drugs were determined. The growing inhibitory concentration of 100%, 100%,≥80%, for AMB, VRC ,ICZ act as respective MIC. For caspofungin, the minimal effective concentration (MEC) was determined as the lowest drug concentration showing morphology change of filaments. The fractional inhibitory concentration (FIC) was used to evaluate the effect of combination therapy. FIC was calculated by the following equation: FIC = MICcombination/MICA drug alone+ MICcombination/MICB drug alone. Results MIC90 of AMB, ICZ, CBF, VRC against 72 isolates of filamentous fungi were 8 μg/ml, 4 μg/ml, 2 μg/ml, 8 μg/ml, respectively. MICs range of combined AMB + ICZ, AMB + VRC, ICZ + VRC were 0. 125-16. 97, 0. 2452-1.25, and 0.0625-8. 25 μg/ml respectively. The percent of synergistic interaction of AMB + VRC against filamentous fungi (20.0%-88.9% ) was higher than those of AMB + ICZ ( 10.0% -62.5% ) and ICZ + VRC ( 20.0% - 44.4% ) ( P=0.007 <0.05 ). Conclusions The antifungal activities of four kinds antifungal drugs against 72 strains of filamentous fungi vary in vitro. The therapy of AMB combined with VRC is maybe better than AMB + ICZ and ICZ + VRC for severe fungi infection.

Estudio de la sensibilidad a los antimicrobianos de patógenos periodontales / Study of antimicrobial susceptibility of periodontal pathogens

Considerando que las diversas fallas en la implementación de la terapia antimicrobiana para el tratamiento de las periodontitis conducen a la aparición de cepas resistentes a los mismos, el objetivo de este trabajo fue realizar un estudio preliminar del patrón de resistencia a los antimicrobianos de uso común en la clínica de cepas de Porphyromonas gingivalis, Prevotella intermedia y Fusobacterium nucleatum. La prueba de sensibilidad a los antimicrobianos se realizó por el método de dilución en agar descrito por la NCCLS (National Committee for Clinical Laboratory Standards). Se probaron antimicrobianos seleccionados entre los más utilizados en la práctica clínica en nuestro medio: amoxicilina, clindamicina, doxiciclina, eritromicina, metronidazol y tetraciclina. Los resultados mostraron que el 100 por ciento de las cepas de P. gingivalisfueron resistentes a metronidazol y sensibles a tetraciclina, y un 33 por ciento sensibles a clindamicina. Las CIMs obtenidas para amoxicilina estuvieron entre 1 y 32 mg/ml, para doxiciclina entre 0,125 y 5 mg/ml y para eritromicina entre 8 y >32 mg/ml. En el caso de P. intermedia, se observó también un 100 por ciento de resistencia a metronidazol, un 67 por ciento de sensibilidad a tetraciclina y un 62,5 por ciento a clindamicina. Las CIMs para amoxicilina estuvieron entre 0,125 y 16 mg/ml, para doxicilina entre 0,125 y 4 mg/ml, y para eritromicina entre 8 y > 32 mg/ml. El 100 por ciento de las cepas de F. nucleatum resultaron sensibles a tetraciclina y resistentes a metronidazol, y el 25 por ciento fueron sensibles a clindamicina. En cuanto a amoxicilina, las CIMs estuvieron entre 0,125 y 16 mg/ml, para doxicilina entre 0,125 y 4 mg/ml, y eritromicina entre 16 y >32 mg/ml. Los patrones de resistencia obtenidos con estas cepas mostraron en general mayores porcentajes de resistencia que lo reportado por otros autores, lo que podría deberse a la falta de políticas de control en el uso de antimicrobianos en nuestro país...

Taking into account that several failures in antibiotic treatments used in periodontitis are driving to the appearance of resistant strains, the aim of this work was to realize a preliminary study of the resistance pattern to commonly used antimicrobials of regional Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum strains. Antibiotic susceptibility test was performed by NCCLS (National Committee for Clinical Laboratory Standards) agar dilution method. Proof antibiotics were selected among the most used in the clinical practice in our region: amoxicillin, clindamycin, doxycycline, erythromycin, metronidazole and tetracycline. The results showed that 100 percent of P.gingivalis strains were resistant to metronidazole and susceptible to tetracycline, and 33 percent susceptible to clindamycin. The MICs obtained for amoxicillin were between 1 and 32 mg/ml, for doxycycline between 0,125 and 5 mg/ml and for erythromycin between 8 and >32 mg/ml. In the case of P. intermedia, were also observed a 100 percent of resistance to metronidazole, 67 percent of susceptibility to tetracycline, and 62,5 percent of susceptibility to clindamycin.. The MICs for amoxicillin were between 0,125 y 16 mg/ml, for doxycycline between 0,125 and 4 mg/ml, and for erythromycin between 8 and >32 mg/ml. 100 percent of F. nucleatum strains were susceptible to tetracycline and resistant to metronidazole, and a 25 percent susceptible to clindamycin. MICs to amoxicillin were between 0,125 y 16 mg/ml, for doxycycline between 0,125 and 4 mg/ml, and to erythromycin between 16 and >32 mg/ml. Resistance patterns obtained with strains of our region showed higher percentages of resistance than those reported by other authors, which might owe to the lack of control politicise for the use of antimicrobials in our country. However, MICs values founded for the 50 and 90 percent of strains are similar to tose reported by NCCLS, except in the case of doxycycline, ...

Comparative evaluation of the Nitrate Reductase Assay and the Resazurin Microtitre Assay for drug susceptibility testing of Mycobacterium tuberculosis against first line anti-tuberculosis drugs

Tuberculosis remains as a serious infection disease of worldwide distribution, with high morbidity and mortality, mainly in low socio-economic condition countries. The state of emergency of tuberculosis caused by the resistant and multidrug-resistant (MDR) strains, became the main threat to the tuberculosis treatment and control programs. A fast detection method for the resistant strains will allow the implementation of an adequate treatment and contribute for controlling the dissemination of these resistant strains. This study evaluated the performance of the nitrate reductase assay in solid (NRA-LJ) and liquid (NRA-7H9) media, to determine the susceptibility to first line anti-tuberculosis drugs: isoniazid (INH), rifampicin (RMP), ethambutol (EMB) and streptomycin (SMR). Both methods NRA-LJ and NRA-7H9 were evaluated among 18 strains with a known susceptibility profile. The resazurin microtiter assay (REMA) was performed as a reference method. One hundred percent of accordance was observed between NRA-7H9 and REMA for the four tested drugs. When the NRA-LJ method was compared to REMA, the sensitivity and the specificity to INH, RMP, EMB and SMR were 100 percent, 100 percent, 85.7 percent, 76.9 percent and 80 percent, 100 percent, 75 percent and 80 percent, respectively. From the 57 clinical isolates of M. tuberculosis evaluated by NRA-7H9 and REMA, 56 (98.2 percent) were sensitive to all antibiotics tested (INH, RMP, EMB and SMR) by the NRA-7H9 method, while three of these strains were resistant to INH by REMA. One strain showed resistance to INH and RMP for both methods, and MIC of 1.0 µg/ml to INH for both methods, while MIC of 1.0 and 2.0 µg/ml to RMP for REMA and NRA-7H9, respectively. The three assays showed a high level of agreement for rapid detection of rifampicin and isoniazid resistance. Regarding rapidness, the detection of color change in the NRA method is within instants as compared to the overnight incubation required...

A tuberculose permanece como uma séria doença infecciosa, com distribuição mundial, alta morbidade e mortalidade, ocorrendo principalmente em paises com baixa condição econômica. O estado de emergência da tuberculose causada por cepas resistentes e multirresistentes tornou-se uma importante ameaça para o tratamento e programas de controle da tuberculose. Uma rápida detecção de cepas resistentes permitirá a implantação de um tratamento adequado e contribuirá para controlar a disseminação destas cepas. Este estudo avaliou a performace do ensaio nitrato redutase em meio sólido (NRA-LJ) e meio líquido (NRA-7H9), para determinar a sensibilidade frente aos fármacos antituberculosos de primeira linha: isoniazida (INH), rifampicina (RMP), etambutol (EMB) and estreptomicina (SMR). Ambos os métodos, NRA-LJ e NRA-7H9, foram avaliados com 18 cepas com conhecido perfil de sensibilidade. O ensaio de microplaca com resazurina (REMA) foi utilizado como método de referência. A concordância observada entre NRA-7H9 and REMA foi de 100 por cento para os quatro fármacos testados. Quando o método NRA-LJ foi comparado com o REMA, a sensibilidade e especificidade para INH RMP e SMR foram de 100 por cento, 100 por cento, 85,7 por cento, 76,9 por cento e 80 por cento, 100 por cento, 75 por cento and 80 por cento, respectivamente. Dos 57 isolados clinicos de M. tuberculosis avaliados por NRA-7H9 e REMA, 56 (98.2 por cento) foram sensíveis a todos antibióticos testados (INH, RMP, EMB e SMR) pelo método NRA-7H9, enquanto três destas cepas foram resistentes para INH pelo REMA. Uma cepa mostrou resistência para INH e RMP por ambos os métodos, e CMI de 1,0 µg/ml para INH para ambos os métodos, enquanto CMI de 1,0 e 2,0 µg/ml para RMP pelo REMA e NRA-7H9, respectivamente. Os três ensaios mostraram um alto nível ded concordância para uma rápida detecção de resistência a rifampicina e isoniazida. Com relação à rapidez na obtenção dos resultados, a detecção na mudança de...

Perspectives on surveillance of microbiol resistance / 中华检验医学杂志

The purpose of setting project of surveillance of antimicrobial resistance is:(1)To better understand development of resistance in local hospital,or country,and to compare with data from other countries;(2)To cooperate with clinic for controlling outbreak caused by clone strain-resistance;(3)To help doctors for management of treatment;and(4)To mining the mechanisms of resistance.In this text the history of surveillance of antimicrobial resistance in Peking Union Medical College Hospital starting in 1983 to present and the achievement were ihtroduced.But the fight against resistance between human being and microorganism is eternal and difficult.The main target pathogens and antimicrobial resistance at 21 st sentry were also introduced.The paper emphasized necessity and possibility of distinguishing CA-MRSA and HA-MRSA,VRSA,VISA and hVISA,ESBLs,AmpC and carbapenemases.To pay more attention to the relationship between resistance and serotypes in Streptococcus pneumoniae,it is important to survey the emerging resistance of the new antibiotics in China,such as linezolid,tigecycline,daptomycin,ceftobiprole and new fluoroquinolones and others.It is needed to develop pharmacokinetic/pharmacodynamic(PK/PD)- breakpoints as a substitute for old breakpoints,and to introduce emerging technologies,such as data mining artificially intelligent system,geographic information system,multiplex real time PCR with advanced reading techniques and other molecular methods for routine work in Clinical microbiology,SO that we can wisely fight against microbial resistance effectively.

Comparison of Anti-mycobacterial Drug Susceptibility Test Results by Institutes and Methods / 대한임상미생물학회지

BACKGROUND: The purposes of the current study were to evaluate the concordant rates of anti-mycobacterial drug susceptibility test (DST) results in different solid media performed in different institutes, and to determine reliable susceptible testing methods. METHODS: One hundred and twenty two Mycobacterium tuberculosis strains were isolated from patients in A Hospital in 2005. DSTs were performed by the absolute concentration method using L?wenstein Jensen medium in both A Hospital (method A-1) and B Institute (method B-1) and by the proportion method using Middlebrook 7H10 agar in B Institute (method B-2). Nine drugs were used including isoniazid and rifampin. Sensitivity and specificity of each method were estimated by using the acceptable standard of 90% for isoniazid and rifampin and 80% for other drugs. The therapeutic outcomes of quinolone-administered patients were evaluated according to ofloxacin susceptibility results. RESULTS: Method B-1 showed sensitivity and specificity levels over the acceptable standard levels for all drugs. Method B-2 showed specificity lower than the acceptable levels for rifampin and cycloserine. Method A-1 showed specificity lower than the acceptable levels for isoniazid, streptomycin, p-aminosalicylic acid, and ofloxacin and sensitivity lower than the acceptable levels for prothionamide and cycloserine. The concordance rates of therapeutic outcomes with method B-1, method B-2, and method A-1 were 77%, 74%, and 65%, respectively. CONCLUSION: The drug susceptibility results for some drugs were discordant between the testing laboratories and media, requiring an urgent application of quality control programs to raise the reliability of anti-mycobacterial DST.

Study of MTT and resazurin assays for susceptibility test to first-line anti-tuberculosis drugs / 中华检验医学杂志

Objecflve To evaluate the performance of two rapid and low-cost metheds(MTT test,and rosazurin mierotitre assay)for the detection of resistance to first-line drugs in Mycobacterium tuberculosis.Methods sixty-four Myeobaeterium tuberculosis clinical isohtes were tested by the MTT test and the rosazuxin microtitre assay(REMA)respectively,and the results were compared with those obtained with the absolute concentration method on L(o)wenstein Jensen medium.Results The MTT test and the resazurin microtitre assay showed a good agreement compared with the absolute concentration method for all first-line drugs tested.The sensitibity,specificity and accuracy of the MTT test were 94.8%,96.0%,95.3%,for RFP;93.8%,93.8%,93.8% for INH;92.9%,96.O%,95.3% for EMB,90.6%,87.5%,89.1% for SM,respectively.The sensitivity,specificity and accuracy of the resazurin microtitre assay were 92.3%,96.0%,93.8%,for RFP;90.6%,90.6%,90.6% for INH;92.9%,94.0%,93.8% for EMB,87.5%,87.5%,87.5% for SM,respectively.The Kappa value of the MTT test and the absolute concentration method for the detection of resistance to RFP,INH,EMB,SM were 0.857,0.831,0.714,0.792.respeedvely;The Kappa value of the regazurin mierotitre assay and the absolute concentration method for the detection of resistance to RFP,INH,EMB,SM were 0.871,0.826,0.826,0.750,respectively.The Kappa value of the MTT test and the resazurin microtitre assay for the detection of resistance to RFP,INH,EMB,SM wefe 0.889,0.875.0.787,0.844,respectively.Conclusions Both MTT test and the resazurin microtitre assays are simple,rapid,low-cost and sensitive for rapid detection of resistance to first-line drugs.They could be promising methods for susceptibility assay of the first-line antituberculosis drugs in low-resource countries.