IDENTIFICATION AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF ENTEROBACTER SPECIES BY VITEK-2 SYSTEM ISOLATED FROM VARIOUS CLINICAL SPECIMEN IN GOVT MEDICAL COLLEGE KOTA (RAJASTHAN)

Background: Enterobacter were proposed as a genus in 1960 by Hormaeche and Edwards based on the division of the former genus Aerobacter into motile, ornithine decarboxylase (ODC)–positive strains (Enterobacter) and nonmotile ODC-negative strains (Klebsiella). The Vitek-2 system is the second generation of Vitek and offers a more sophisticated model of data analysis as well as a fully automated process for card identification, organism suspension dilution and card filling. To study Aim and Objectives: identification and antimicrobial susceptibility pattern of Enterobacter species by Vitek-2 system isolated from various clinical samples. Material and Methods: A total of 100 Enterobacter species obtained from various clinical samples like urine, pus, sputum, endotracheal aspirate and body fiuids (pleural, ascitic, peritoneal and CSF) etc. of patients received at Department of Microbiology, Government Medical College & Associated Group of Hospitals, Kota during a period of approximately 1 year from May 2021 to May 2022 were taken for the identification and Antibiotic sensitivity testing by Vitek-2 system. Out of 100 Enterobacter isolates, 69% w Result: ere E.cloacae and 31% were E.aerogenes. Antimicrobial susceptibility results of Enterobacter species revealed the susceptibility of 56.41% for Nitrofurantoin, 69% for Piperacillin/ Tazobactam and 72% for Cefoperazone/ salbactam. Enterobacter seems to be emerged with increasi Conclusion: ng resistance to multiple antibiotics.

Identificación y sensibilidad antibiótica directas desde el hemocultivo positivo para bacilos gram negativos. Rendimiento comparativo de los sistemas Vitek 2C y Phoenix / Direct identification and susceptibility testing from positive blood cultures. A head-to-head performance comparison between Vitek 2C and Phoenix systems / Identificação e sensibilidade antibiótica diretas a partir da hemocultura positiva para bacilos gram negativos. Desempenho comparativo dos sistemas Vitek 2C e Phoenix

Resumen El objetivo de este estudio fue comparar los resultados de las pruebas de identificación y sensibilidad antimicrobiana obtenidos por los sistemas Vitek 2C (bioMérieux, Francia) y Phoenix (Becton Dickinson, EE.UU.) directamente a partir de hemocultivos positivos. Se realizó un estudio observacional prospectivo en el Hospital Naval Pedro Mallo de Buenos Aires, Argentina, que incluyó 70 bacteriemias monomicrobianas por gram negativos. Se obtuvo una identificación correcta por Vitek® 2C y por Phoenix del 100% y 97% respectivamente [p: no significativa (NS)]. La concordancia categórica para todos los antimicrobianos fue 97,1% y 98,1% (p: NS) con Vitek 2C y con Phoenix respectivamente. El tiempo medio para obtener un resultado fue de 10,19 h y 13,8 h (p: NS), respectivamente. Vitek 2C y Phoenix son herramientas importantes, rápidas y confiables para la identificación y las pruebas de sensibilidad realizadas directamente a partir de hemocultivos positivos.

Abstract The aim of this study was to compare the results of identification and antimicrobial susceptibility tests obtained by the Vitek 2C (bioMérieux, France) and Phoenix (Becton Dickinson, USA) systems directly from positive blood cultures. A prospective observational study was performed at the Pedro Mallo Navy Hospital in Buenos Aires, Argentina, which included 70 monomicrobial bacteremias by gram negative rods. Correct identification by Vitek® 2C and Phoenix was 100% and 97%, respectively [p: not significant (NS)]. Categorical agreement for all antimicrobials was 97.1% and 98.1% (p: NS) with Vitek 2C and Phoenix, respectively. The mean time to result was 10.19 h and 13.8 h (p: NS), respectively. Vitek 2C and Phoenix are important, rapid and reliable tools for identification and susceptibility testing when performed directly from positive blood cultures.

Resumo O objetivo deste estudo foi comparar os resultados dos testes de identificação e de suscetibilidade antimicrobiana obtidos pelos sistemas Vitek 2C (bioMérieux, França) e Phoenix (Becton Dickinson, EUA) diretamente a partir de culturas de sangue positivas. Foi realizado um estudo observacional prospectivo no Hospital Naval Pedro Mallo em Buenos Aires, Argentina, incluindo 70 bacteriemias monomicrobianas devido a gram negativos. A identificação correcta por Vitek® 2C e Phoenix obtida foi de 100% e 97% respectivamente [p: não significativo (NS)]. O acordo categórico para todos os antimicrobianos foi de 97,1% e 98,1% (p: NS) com Vitek 2C e Phoenix respectivamente. O tempo médio para obter o resultado foi de 10,19 h e 13,8 h (p: NS), respectivamente. Vitek 2C e Phoenix são ferramentas importantes, rápidas e fiáveis para a identificação e testes de sensibilidade realizados diretamente a partir de hemoculturas positivas.

Rapid bacterial identification and antimicrobial susceptibility testing assay in positive blood cultures / 预防医学

Objective@#To establish a rapid bacterial identification and antimicrobial susceptibility testing assay in positive blood cultures, so as to provide insights into timely diagnosis and treatment of bloodstream infections.@*Methods@#A total of 1 154 blood culture samples were collected from inpatients in Zhejiang Hospital from February to May, 2022. The bacterial isolates were enriched and purified using improved separation gel method, and bacterial identification and antimicrobial susceptibility tests were performed using VITEK2 mass spectrometry system and VITEK2 Compact automated microbiology system. The accuracy of the new assay for bacterial identification and antimicrobial susceptibility tests was evaluated with the conventional VITEK 2 compact system as the standard. @*Results@#Of 1 154 blood culture specimens, the conventional VITEK 2 compact system detected 174 positives and 980 negatives. The new assay and the conventional VITEK 2 compact system identified consistent bacterial isolates in 165 out of 174 positive blood culture samples, and the accuracy of bacterial identification was 94.83% for the new assay, with a 99.21% accuracy for identifying Gram-negative bacteria and 82.22% for Gram-positive bacteria. Antimicrobial susceptibility tests were performed in 158 bacterial isolates, and the new assay presented a 90.17% accuracy, with a 90.27% accuracy for Gram-negative bacteria and 89.74% for Gram-positive bacteria. The conventional VITEK 2 compact system required 30 hours and longer to complete bacterial identification and antimicrobial susceptibility tests, and the new assay required 9 to 18 hours.@*Conclusions@#The new rapid bacterial identification and antimicrobial susceptibility testing assay shortens the time of bacterial culture, achieves rapid bacterial identification and antimicrobial susceptibility testing in blood culture specimens and has a high accuracy that meets clinical needs, which facilitates rapid diagnosis and treatment of bloodstream infections.

Comparación de dos métodos comerciales para la determinación de la concentración mínima inhibitoria de meropenem en Klebsiella pneumoniae productora de carbapenemasa tipo KPC / Comparison of two commercial methods for determination of the minimum inhibitory meropenem concentration in KPC carbapenemase-producing Klebsiella pneumoniae

Introducción: El tratamiento de las infecciones por Klebsiella pneumoniae productora de carbapenemasa tipo KPC es complicado debido a las escasas opciones terapéuticas existentes, lo cual obliga a optimizar los esquemas terapéuticos disponibles. Objetivo: Determinar la concordancia de la tarjeta AST-N272 del Sistema Vitek 2 Compact y las tiras M.I.C.ETM Evaluator con la dilución en agar para la determinación de la concentración mínima inhibitoria del meropenem en Klebsiella pneumoniae productora de carbapenemasa tipo KPC. Métodos: Se estudiaron 53 aislados de K. pneumoniae bla KPC positivas no clonales, provenientes de hisopados rectales recolectados en diferentes unidades hospitalarias de Guayaquil, Ecuador, entre enero a junio de 2016. Se determinó la concentración mínima inhibitoria de meropenem por dilución en agar (método de referencia), así como por el sistema Vitek 2 Compact (AST-N272) y las tiras M.I.C.ETM. Se determinó la CMI 50, CMI 90 y la concordancia esencial. Resultados: El rango de la CMI de meropenem de los aislados estudiados fue de 1 a ≥ 32 µg/mL, con una CMI50= 4 µg/mL y una CMI90= ≥ 32 µg/mL. El 86,79 por ciento (n= 46) de los aislados tuvo una CMI≤ 8 µg/mL. Se observó un 94,33 por ciento de concordancia esencial con las tiras M.I.C.ETM, mientras que la tarjeta AST-N272 mostró una concordancia esencial inferior al 50 por ciento. Conclusiones: Los resultados sugieren posibles implicaciones en el tratataminto del paciente, pues reduce opciones terapéuticas en contextos de difícil manejo. Además, resaltan la necesidad de la confirmación de la resistencia a carbapenémicos mediante el método de Kirby Bawer en aquellos laboratorios que tienen métodos automatizados para estudios de susceptibilidad(AU)

Introduction: The treatment for KPC carbapenemase-producing Klebsiella pneumoniae infections is complicated, due to the scant therapeutic options available, which forces us to optimize the therapies at hand. Objective: Determine the agreement between the AST-N272 card of the Vitek 2 Compact system and the M.I.C.E.TM Evaluator strips, and the agar dilution method for determination of the minimum inhibitory meropenem concentration in KPC carbapenemase-producing Klebsiella pneumoniae. Methods: A study was conducted of 53 positive non-clonal K. pneumoniae bla KPC isolates from rectal swabs collected at several hospitals in Guayaquil, Ecuador, from January to June 2016. Minimum inhibitory meropenem concentration was determined by agar dilution (reference method), the Vitek 2 Compact system (AST-N272) and M.I.C.E.TM strips. Determination was made of MIC 50, MIC 90 and essential agreement. Results: The meropenem MIC range for the isolates studied was 1 to ≥ 32 µg/ml, with MIC50= 4 µg/ml and MIC90= ≥ 32 µg/ml. In 86.79 percent (n= 46) of the isolates MIC was ≤ 8 µg/ml. Essential agreement was 94.33 percent with the M.I.C.E.TM strips and under 50 percent with the AST-N272 card. Conclusions: The results obtained suggest potential implications for the treatment of patients, since therapeutic options are reduced in difficult management contexts. They also highlight the need for confirmation of carbapenem resistance by the Kirby-Bauer procedure in laboratories equipped with automated methods for susceptibility studies(AU)

Streptococcus pseudoporcinus: a rare cause of bacteraemia in an immune-compromised patient

Streptococcus pseudoporcinus, a ß-haemolytic Streptococcus is known to cause genital infections. Author report a rare case of Streptococcus pseudoporcinus bacteremia in an immune-compromised male patient diagnosed with acute myeloid leukemia eight months back. The organism was identified as a beta hemolytic bacterium which was catalase negative, oxidase positive and bacitracin resistant. Automated methods (VITEK-2) confirmed the organism to be Streptococcus pseudoporcinus.

Linezolid Resistance in Methicillin-Resistant Staphylococcus aureus in Korea: High Rate of False Resistance to Linezolid by the VITEK 2 System

As various linezolid resistance mechanisms have been identified in methicillin-resistant Staphylococcus aureus (MRSA), we investigated the molecular characteristics of MRSA with elevated linezolid minimum inhibitory concentrations (MICs), using the VITEK 2 system (bioMérieux, Marcy-l'Étoile, France). Twenty-seven MRSA isolates from 14 patients exhibiting linezolid MICs ≥8 µg/mL were examined by broth microdilution (BMD) test as well as by sequencing for mutations in the 23S rRNA gene or ribosomal proteins (L3, L4, and L22) and the presence of the optrA, cfr, and cfr(B) genes. Of the 27 isolates, four (14.8%) from one patient were confirmed as linezolid resistant by BMD and harbored a 23S rRNA T2500A mutation. The remaining 23 were confirmed as linezolid susceptible, indicating that the linezolid-resistant results were major errors generated by VITEK 2. The most commonly detected mutation (19/27, 70.4%), L3 Gly152Asp, was detected in only linezolid-susceptible isolates. No isolates contained optrA, cfr, or cfr(B) or any L4 or L22 protein alterations. Our results show that the 23S rRNA T2500A mutation was mainly associated with linezolid resistance, while the L3 Gly152Asp mutation was not related to linezolid resistance. A confirmatory test is recommended for VITEK 2 linezolid-resistant results owing to the high probability of false resistant results.

Isolation, identification and antibiogram profiling of bacteria isolated from water, seafood, and macroplastic samples from Baseco Beach, Manila Bay

Background and Objective@#Manila Bay plays an important role both in economics and ecology because it serves as the major economic center of the Philippines and as it harbors different habitats and biodiversity. Unfortunately, it is threatened by various pollutions including the unregulated discharge of wastewater from industrial, agricultural, and household sectors and improper disposal of trash such as macroplastics among others. All these contributes to the current state of Manila Bay. This study identified bacteria isolated from water, seafood and floating macroplastic samples from Baseco Beach, Manila Bay and determined their antibiogram profiles. @*Methodology@#Bacterial isolates were obtained from water, seafoods and macroplastic samples from Baseco Beach, Manila Bay using conventional culture techniques. Identification of the isolates was done using Vitek-2 Automated System and antibiogram profiling was done using Kirby-Bauer Disk Diffusion Susceptibility Test. @*Results and Conclusions@#A total of 30 bacterial isolates were obtained from different samples from water, seafood and macroplastic samples from Baseco Beach, Manila Bay. These isolates were identified and found to belong to 13 different bacterial species with Bacillus spp. comprising 33.33% of the isolates (10 out of 30), and Vibrio alginolyticus comprising 23.33% of the isolates (7 out of 30) and the other species comprise the remaining 43.34% (Pseudomonas spp., Vibrio fluvialis, Klebsiella pneumoniae, Shewanella alga, Sphingomonas paucimobilis, Staphylococcus haemolyticus, Chryseobacterium indologenes, Myroides sp. and Aeromonas salmonicida). Of these, six out of 30 isolates (20%) showed susceptibility to all six representative antibiotics used (Cefazolin 30μg, Gentamicin 10 μg, Chloramphenicol 30 μg, ampicillin 10 μg, Cefuroxime 30 μg, Ceftazidime 30 μg) while 7 isolates (23.33%) were resistant to only one class of antibiotic. Moreover, 17 out of 30 isolates (56.66%) were resistant to two or more classes of antibiotic while only one isolate (3.33%) was found to be resistant to gentamicin. All 30 isolates (100%) were susceptible to chloramphenicol. Interestingly, three antibiotic resistant (AMR) bacteria were isolated from macroplastics namely Pseudomonas oleovorans (S2), Vibrio alginolyticus (S5), and Pseudomonas alcaligenes (S29) which were all resistant to ampicillin and cefazolin. This is the first study in the Philippines to isolate AMR bacteria from macroplastics from Manila Bay. The presence of AMR bacteria in macroplastics shows that these materials can be a reservoir for its dynamics and distribution. Lastly, with the emergence of antimicrobial resistant bacteria, the elucidation of the antibiogram profile of bacteria is necessary to determine its implication sand threats to public health. This study served as a baseline study of presence of AMR bacteria in macroplastic samples from Manila Bay.

Biochemical identification techniques and antibiotic susceptibility profile of lipolytic ambiental bacteria from effluents / Técnicas de identificação bioquímica e perfil de suscetibilidade antibiótica de bactérias ambientais lipolíticas de efluentes

Abstract Different methodologies have been developed throughout the years to identify environmental microorganisms to improve bioremediation techniques, determine susceptibility profiles of bacteria in contaminated environments, and reduce the impact of microorganisms in ecosystems. Two methods of bacterial biochemical identification are compared and the susceptibility profile of bacteria, isolated from residential and industrial wastewater, is determined. Twenty-four bacteria were retrieved from the bacteria bank of the Environmental Microbiology Laboratory at the Institute of Biology (IB) of the Universidade Federal de Pelotas, Pelotas, Brazil. Bacteria were identified by conventional biochemical tests and by the VITEK ®2 automated system. Further, the susceptibility profile to antibiotics was also determined by the automated system. Six species of bacteria (Raoutella planticola, K. pneumoniae ssp. pneumoniae , Serratia marcescens, Raoutella sp., E. cloacae and Klebsiella oxytoca) were identified by conventional biochemical tests, while three species of bacteria (K. pneumoniae ssp. pneumoniae, S. marcescens and K. oxytoca ) were identified by VITEK®2 automated system. VITEK ®2 indicated agreement in 19 (79.17%) isolates and difference in five (20.83%) isolates when compared to results from conventional biochemical tests. Further, antibiotic susceptibility profile results showed that all isolates (100%) were resistant to at least one out of the 18 antibiotics tested by VITEK®2. Thus, no multi-resistant bacteria that may be used in effluent treatment systems or in bioremediation processes have been reported. Results indicate VITEK ® 2 automated system as a potential methodology in the determination of susceptibility profile and identification of environmental bacteria.

Resumo Diferentes metodologias foram desenvolvidas ao longo dos anos para identificar microrganismos ambientais para melhorar as técnicas de biorremediação, determinar perfis de suscetibilidade de bactérias em ambientes contaminados e reduzir o impacto de microrganismos nos ecossistemas. Dois métodos de identificação bioquímica bacteriana são comparados e o perfil de susceptibilidade de bactérias, isoladas de efluentes residenciais e industriais, é determinado. Vinte e quatro bactérias foram coletadas do banco de bactérias do Laboratório de Microbiologia Ambiental do Instituto de Biologia (IB) da Universidade Federal de Pelotas, Pelotas, Brasil. As bactérias foram identificadas por testes bioquímicos convencionais e pelo sistema automatizado VITEK®2. Além disso, o perfil de suscetibilidade aos antibióticos também foi determinado pelo sistema automatizado. Seis espécies de bactérias (Raoutella planticola , K. pneumoniae ssp. pneumoniae, Serratia marcescens, Raoutella sp., E. cloacae e Klebsiella oxytoca) foram identificadas por testes bioquímicos convencionais, enquanto três espécies de bactérias (K. pneumoniae ssp. pneumoniae, S. marcescens e K. oxytoca) foram identificados pelo sistema automatizado VITEK®2. VITEK®2 indicou concordância em 19 (79,17%) isolados e diferença em cinco (20,83%) isolados quando comparados aos resultados de testes bioquímicos convencionais. Além disso, os resultados do perfil de suscetibilidade aos antibióticos mostraram que todos os isolados (100%) foram resistentes a pelo menos um dos 18 antibióticos testados pelo VITEK®2. Assim, não foram relatadas bactérias multirresistentes que possam ser usadas em sistemas de tratamento de efluentes ou em processos de biorremediação. Os resultados indicam que o sistema automatizado VITEK ® 2 é uma metodologia potencial na determinação do perfil de suscetibilidade e identificação de bactérias ambientais.

In vitro resistance of Enterobacter cloacae isolated from fresh seafood to colistin

Abstract INTRODUCTION: Enterobacter cloacae is a clinically important bacterium from the Enterobacteriaceae family. This study evaluated resistance of E. cloacae strains from fish (n=14) and shrimp (n=9) to colistin. METHODS: Biochemical identification and antimicrobial susceptibility tests were carried out in an automated Vitek®2 instrument. RESULTS: Colistin resistance was observed in 21.4% and 66.7% of the strains from fish and shrimp, respectively. We observed minimum inhibitory concentrations of ≥16 mg/L and ≤5 mg/L in 8 and 15 of all strains, respectively. CONCLUSIONS: Fish and shrimp can carry drug-resistant enterobacteria, which can be of clinical interest.

Antifungal susceptibility profile of diferent yeasts isolates from wild animals, cow's milk with subclinical mastitis and hospital environment / Perfil de suscetibilidade antifúngica de diferentes leveduras isoladas da microbiota de animais silvestres, leite com mastite subclínica e ambiente hospitalar

Abstract Yeast infections have acquired great importance due to increasing frequency in immunocompromised patients or patients undergoing invasive diagnostic and therapeutic techniques, and also because of its high morbidity and mortality. At the same time, it has been seen an increase in the emergence of new pathogenic species difficult to diagnose and treat. The aim of this study was to determine the in vitro susceptibility of 89 yeasts from different sources against the antifungals amphotericin B, voriconazole, fluconazole and flucytosine, using the VITEK® 2 Compact system. The antifungal susceptibility was performed automatically by the Vitek® 2 Compact system. The origin of the yeasts was: Group 1 - microbiota of wild animals (W) (26/89), 2 - cow's milk with subclinical mastitis (M) (27/89) and 3 - hospital enviorment (H) (36/89). Of the 89 yeasts submitted to the Vitek® 2 test, 25 (20.9%) were resistant to fluconazole, 11 (12.36%) to amphotericin B, 3 (3.37%) to voriconazole, and no sample was resistant to flucytosine. Regarding the minimum inhibitory concentration (MIC), fluconazole showed an MIC between 1 and 64 mg/mL for the three groups, voriconazole had an MIC between 0.12 and 8 mg/mL, amphotericin B had an MIC between 0.25 and 4 mg/mL for group H and group W respectively, between 0.25 and 16 mg/mL for group M and flucytosine had an MIC equal to 1μg/mL for all groups. The yeasts isolated from the H group showed the highest resistance to fluconazole 12/89 (13.49%), followed by group W (7.87%) and group M (5.62%). The more resistant group to voriconazole was followed by the M and H groups, the W group showed no resistance to this antifungal. Group H was the least resistant (2.25%) to amphotericin.

Resumo As infecções por leveduras têm adquirido grande importância, devido ao aumento da sua frequência em pacientes imunocomprometidos ou pacientes submetidos a técnicas diagnosticas e terapêuticas agressivas, e devido sua alta morbidade e mortalidade. Paralelamente tem-se observado um incremento na aparição de novas espécies patógenas difíceis de diagnosticar e tratar. O objetivo desse estudo foi avaliar a suscetibilidade in vitro de 89 leveduras de diferentes origens frente aos antifúngicos Anfotericina B, Voriconazol, Fluconazol e Fluocitocina pelo Sistema Vitek® 2. O antifungigrama foi realizado automaticamente pelo Vitek® 2 Compact. A origem das leveduras foi: Grupo 1- Microbiota de Animais Silvestres (S) (26/89), 2- Leite com mastite bovina subclínica (L) (27/89) e 3- Ambiente Hospitalar (H) (36/89). Das 89 leveduras submetidas à carta Vitek®, 25 (20.09%) foram resistentes ao fluconazol, oito (8.99%) à anfotericina B, três (3.37%) ao voriconazol, e nenhuma amostra mostrou-se resistente a fluocitosina. O grupo três (H) foi mais resistente ao fluconazol que os demais, já o dois (L) foi mais resistente ao voriconazol e a anfotericina B que os outros dois. O fluconazol pode ter apresentado maior número de resistências devido ser um fármaco comumente usado principalmente em humanos. As leveduras isoladas de humanos apresentaram maior número de resistências aos fármacos testados do que as leveduras isoladas de animais silvestres. O que pode ocorrer devido a uma maior exposição dos humanos aos fármacos em relação aos animais que vivem isolados em ambientes selvagens e na maioria dos casos nunca teve contato com fármacos de qualquer origem.

Evaluation of Vitek MS in identification of clinical filamentous fungi isolates / 中华微生物学和免疫学杂志

Objective@#To evaluate the performance of Vitek MS, an automated mass spectrometry microbial identification system, in identification of clinical filamentous fungi isolates, which provide a new insight into filamentous fungi identification strategy.@*Methods@#Twenty-five isolates of filamentous fungi genetically confirmed by molecular sequencing method were inoculated in different culture conditions to analyze the potential influences of culture conditions on the identification of filamentous fungi with Vitek MS. Further evaluation of the performance of Vitek MS in filamentous fungi identification was carried out with 207 clinical isolates of filamentous fungi and the comparison of the results with those of morphology and sequencing analysis.@*Results@#The performance of Vitek MS in filamentous fungi identification was not significantly influenced by culture conditions. Vitek MS successfully identified 87.9% (182/207) of all tested filamentous fungi. Lacking of reference MS spectra in Vitek database was the main reason that the other isolates could not be identified. Vitek MS was superior to the traditional morphological method in identification of filamentous fungi especially non-Aspergillus molds at species level.@*Conclusion@#Vitek MS is an efficient approach for clinical filamentous fungi identification. Continuous enrichment of the species coverage in database will be of great importance for improving the performance of Vitek MS in identification of filamentous fungi.

Evaluation on the Accuracy of VITEK 2 Compact for the Susceptibility of Carbapenem-Resistant Klebsiella Peumoniae to Amikacin / 现代检验医学杂志

Objective To evaluate the accuracy of VITEK 2 Compact in the detection of the drug susceptibility of carbapenemresistant Klebsiella pneumoniae (CRKP) to Amikacin.Methods The susceptibility for 147 isolates of SRKP to Amikacin were detected by VITEK 2 Compact,disk diffusion method (K-B method) and E-test method,respectively.Results Among the 147 strains of Klebsiella pneumoniae,the drug susceptibility results were consistent between K B and E-test method.Among the 5 strains,the results were totally consistent by VITEK 2 Compact,K-B method and E test method,of which 4 strains were sensitive,1 strains were resistant.There were 142 strains being not consistent between VITEK 2 Compact and E-test method.The results of VITEK 2 Compact were sensitive or intermediate,while E test were drug resistance.Conclusion VITEK 2 Compact is not reliable for the detection of CRKP to Amikacin,which requires that K B method or other methods should be used for the susceptibility of CRKP to Amikacin.

Performance evaluation of the GP68 Antibiotic Susceptibility Testing card in testing the susceptibility of Streptococcuspneumoniae on VITEK 2-Compact system / 中国感染与化疗杂志

Objective To evaluate the performance of GP68 Antibiotic Susceptibility Testing card in testing the susceptibility of Streptococcus pneumoniae on VITEK 2-Compact system,taking E-test as reference.Methods A total of 98 strains of S.pneumoniae were collected and subjected to susceptibility testing using E-test and VITEK 2-Compact (AST-GP68) in Luzhou People's Hospital form January 1 to December 31,2015.Results According to the breakpoints of Clinical and Laboratory Standards Institute (CLSI),category agreement (CA) of penicillin was 80.6％.Very major error (VME) was 0.Major error (ME) was 12.2％,minor error (mE) was 7.1％.CA of ceffriaxone was 90.8％,VME 0,ME 4.1％,mE 5.1％.CA of cefotaxime was 91.8％,VME 0,mE 5.1％,mE 3.1％.CA of meropenem was 85.7％,VME 0,ME 2.0％,mE 12.2％.CA of other antibiotics (amoxicillin,ertapenem,erythromycin,tetracycline,chloramphenicol,telithromycin,linezolid,vancomycin,moxifloxacin,ofloxacin,levofloxacin) was 100％.Conclusions AST-GP68 on VITEK 2-Compact system may have false results of antimicrobial resistance to some antibiotics such as penicillin,ceftriaxone,cefepime,meropenem due to the defects of the underlying principle.Such false results should be verified by other methods in clinical practice.

Identification and virulence analysis of a Streptococcus suis strain isolated from human blood / 中国人兽共患病学报

To identify and analyze the virulence of a bacteria strain isolated from the blood of a patient with suspected Streptococcus suis (S.suis) infection in a hospital of Beijing,we inoculated the bacteria strain isolated from the blood of the patient to the Columbia with sheep blood agar plate,after Gram staining and microscopical examination,serum agglutination test,VITEK 2 Compact microbial identification system test and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) test,S,suis species specific gene 16SrRNA,S.suis species serotype 2 specific virulence gene capsule polysaccharide 2J (cps2J) and virulence gene muramidase-released protein (mrp),hemolysin (sly),extracellular factor protein (ef),glutamate dehydrogenase (gdh) genes,fibronectin-binding protein (fbps),glyceraldehyde-3-phosphate dehydrogenase (gapdh) genes and virulence correlated gene orf2 were further detected by PCR.Results showed that the suspicious bacteria strain of S.suis was identified as S.suis type 2 (S.suis 2) by conventional methods,MALDI-TOF-MS and PCR.PCR results showed that cps2J,sly,ef,gdh,fbps,gapdh and or f2 genes were positive,and mrp gene was negative.In conclusion,the bacteria strain isolated from the patient's blood is sly+/ef+/mrp-virulent S.suis 2.

Susceptibility of Acinetobacter baumannii isolates to eight antimicrobial agents tested by different methods / 中国感染与化疗杂志

Objective The purpose of this study was to analyze the susceptibility profile of Acinetobacter baumannii to antimicrobial agents,and validate the results of different antimicrobial susceptibility testing methods,for improving the quality of antibiotic resistance monitoring data.Methods The susceptibility data of Hebei Provincial Antimicrobial Resistant Investigation Net were analyzed retrospectively and 126 strains ofA.baumannii were collected.The susceptibility ofA.baumannii to piperacillintazobactam,amikacin,gentamicin,ciprofloxacin,levofloxacin,ceftazidime,imipenem,and meropenem was tested by E-test,KirbyBauer method and VITEK system.Results The susceptibility results of the 126 A.baumannii strains showed that the susceptibility to piperacillin-tazobactam,amikacin,gentamicin,levofloxacin and ceftazidime was significantly different between the three methods (P＜0.05).The categorical agreement,major error,minor error,and very major error of Kirby-Bauer method were within acceptable range.There were evident difference in classification consistency for piperacillin-tazobactam,amikacin,levofloxacin between Kirby-Bauer method and VITEK (P＜0.05).Conclusions Different antimicrobial susceptibility testing methods may lead to different results of resistance monitoring data.Bias may be generated in antibiotic resistance surveillance if different methods are used.The susceptibility results of piperacillin-tazobactam,amikacin,levofloxacin derived from VITEK system should be validated by Kirby-Bauer or E-test method.

Antifungal susceptibility profile of diferent yeasts isolates from wild animals, cows milk with subclinical mastitis and hospital environment

Abstract Yeast infections have acquired great importance due to increasing frequency in immunocompromised patients or patients undergoing invasive diagnostic and therapeutic techniques, and also because of its high morbidity and mortality. At the same time, it has been seen an increase in the emergence of new pathogenic species difficult to diagnose and treat. The aim of this study was to determine the in vitro susceptibility of 89 yeasts from different sources against the antifungals amphotericin B, voriconazole, fluconazole and flucytosine, using the VITEK® 2 Compact system. The antifungal susceptibility was performed automatically by the Vitek® 2 Compact system. The origin of the yeasts was: Group 1 - microbiota of wild animals (W) (26/89), 2 - cows milk with subclinical mastitis (M) (27/89) and 3 - hospital enviorment (H) (36/89). Of the 89 yeasts submitted to the Vitek® 2 test, 25 (20.9%) were resistant to fluconazole, 11 (12.36%) to amphotericin B, 3 (3.37%) to voriconazole, and no sample was resistant to flucytosine. Regarding the minimum inhibitory concentration (MIC), fluconazole showed an MIC between 1 and 64 mg/mL for the three groups, voriconazole had an MIC between 0.12 and 8 mg/mL, amphotericin B had an MIC between 0.25 and 4 mg/mL for group H and group W respectively, between 0.25 and 16 mg/mL for group M and flucytosine had an MIC equal to 1g/mL for all groups. The yeasts isolated from the H group showed the highest resistance to fluconazole 12/89 (13.49%), followed by group W (7.87%) and group M (5.62%). The more resistant group to voriconazole was followed by the M and H groups, the W group showed no resistance to this antifungal. Group H was the least resistant (2.25%) to amphotericin.

Resumo As infecções por leveduras têm adquirido grande importância, devido ao aumento da sua frequência em pacientes imunocomprometidos ou pacientes submetidos a técnicas diagnosticas e terapêuticas agressivas, e devido sua alta morbidade e mortalidade. Paralelamente tem-se observado um incremento na aparição de novas espécies patógenas difíceis de diagnosticar e tratar. O objetivo desse estudo foi avaliar a suscetibilidade in vitro de 89 leveduras de diferentes origens frente aos antifúngicos Anfotericina B, Voriconazol, Fluconazol e Fluocitocina pelo Sistema Vitek® 2. O antifungigrama foi realizado automaticamente pelo Vitek® 2 Compact. A origem das leveduras foi: Grupo 1- Microbiota de Animais Silvestres (S) (26/89), 2- Leite com mastite bovina subclínica (L) (27/89) e 3- Ambiente Hospitalar (H) (36/89). Das 89 leveduras submetidas à carta Vitek®, 25 (20.09%) foram resistentes ao fluconazol, oito (8.99%) à anfotericina B, três (3.37%) ao voriconazol, e nenhuma amostra mostrou-se resistente a fluocitosina. O grupo três (H) foi mais resistente ao fluconazol que os demais, já o dois (L) foi mais resistente ao voriconazol e a anfotericina B que os outros dois. O fluconazol pode ter apresentado maior número de resistências devido ser um fármaco comumente usado principalmente em humanos. As leveduras isoladas de humanos apresentaram maior número de resistências aos fármacos testados do que as leveduras isoladas de animais silvestres. O que pode ocorrer devido a uma maior exposição dos humanos aos fármacos em relação aos animais que vivem isolados em ambientes selvagens e na maioria dos casos nunca teve contato com fármacos de qualquer origem.

Biochemical identification techniques and antibiotic susceptibility profile of lipolytic ambiental bacteria from effluents

Abstract Different methodologies have been developed throughout the years to identify environmental microorganisms to improve bioremediation techniques, determine susceptibility profiles of bacteria in contaminated environments, and reduce the impact of microorganisms in ecosystems. Two methods of bacterial biochemical identification are compared and the susceptibility profile of bacteria, isolated from residential and industrial wastewater, is determined. Twenty-four bacteria were retrieved from the bacteria bank of the Environmental Microbiology Laboratory at the Institute of Biology (IB) of the Universidade Federal de Pelotas, Pelotas, Brazil. Bacteria were identified by conventional biochemical tests and by the VITEK ®2 automated system. Further, the susceptibility profile to antibiotics was also determined by the automated system. Six species of bacteria (Raoutella planticola, K. pneumoniae ssp. pneumoniae , Serratia marcescens, Raoutella sp., E. cloacae and Klebsiella oxytoca) were identified by conventional biochemical tests, while three species of bacteria (K. pneumoniae ssp. pneumoniae, S. marcescens and K. oxytoca ) were identified by VITEK®2 automated system. VITEK ®2 indicated agreement in 19 (79.17%) isolates and difference in five (20.83%) isolates when compared to results from conventional biochemical tests. Further, antibiotic susceptibility profile results showed that all isolates (100%) were resistant to at least one out of the 18 antibiotics tested by VITEK®2. Thus, no multi-resistant bacteria that may be used in effluent treatment systems or in bioremediation processes have been reported. Results indicate VITEK ® 2 automated system as a potential methodology in the determination of susceptibility profile and identification of environmental bacteria.

Resumo Diferentes metodologias foram desenvolvidas ao longo dos anos para identificar microrganismos ambientais para melhorar as técnicas de biorremediação, determinar perfis de suscetibilidade de bactérias em ambientes contaminados e reduzir o impacto de microrganismos nos ecossistemas. Dois métodos de identificação bioquímica bacteriana são comparados e o perfil de susceptibilidade de bactérias, isoladas de efluentes residenciais e industriais, é determinado. Vinte e quatro bactérias foram coletadas do banco de bactérias do Laboratório de Microbiologia Ambiental do Instituto de Biologia (IB) da Universidade Federal de Pelotas, Pelotas, Brasil. As bactérias foram identificadas por testes bioquímicos convencionais e pelo sistema automatizado VITEK®2. Além disso, o perfil de suscetibilidade aos antibióticos também foi determinado pelo sistema automatizado. Seis espécies de bactérias (Raoutella planticola , K. pneumoniae ssp. pneumoniae, Serratia marcescens, Raoutella sp., E. cloacae e Klebsiella oxytoca) foram identificadas por testes bioquímicos convencionais, enquanto três espécies de bactérias (K. pneumoniae ssp. pneumoniae, S. marcescens e K. oxytoca) foram identificados pelo sistema automatizado VITEK®2. VITEK®2 indicou concordância em 19 (79,17%) isolados e diferença em cinco (20,83%) isolados quando comparados aos resultados de testes bioquímicos convencionais. Além disso, os resultados do perfil de suscetibilidade aos antibióticos mostraram que todos os isolados (100%) foram resistentes a pelo menos um dos 18 antibióticos testados pelo VITEK®2. Assim, não foram relatadas bactérias multirresistentes que possam ser usadas em sistemas de tratamento de efluentes ou em processos de biorremediação. Os resultados indicam que o sistema automatizado VITEK ® 2 é uma metodologia potencial na determinação do perfil de suscetibilidade e identificação de bactérias ambientais.

Comparison of the Bruker Biotyper and VITEK MS Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Systems Using a Formic Acid Extraction Method to Identify Common and Uncommon Yeast Isolates

BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and accurate identification of clinical yeast isolates. In-tube formic acid/acetonitrile (FA/ACN) extraction is recommended prior to the analysis with MALDI Biotyper, but the direct on-plate FA extraction is simpler. We compared the Biotyper with the VITEK MS for the identification of various clinically relevant yeast species, focusing on the use of the FA extraction method. METHODS: We analyzed 309 clinical isolates of 42 yeast species (four common Candida species, Cryptococcus neoformans, and 37 uncommon yeast species) using the Biotyper and VITEK MS systems. FA extraction was used initially for all isolates. If ‘no identification' result was obtained following the initial FA extraction, these samples were then retested by using FA (both systems, additive FA) or FA/ACN (Biotyper only, additive FA/ACN) extraction. These results were compared with those obtained by sequence-based identification. RESULTS: Both systems correctly identified all 158 isolates of the four common Candida species after the initial FA extraction. The Biotyper correctly identified 8.7%, 30.4%, and 100% of 23 C. neoformans isolates after performing initial FA, additive FA, and FA/ACN extractions, respectively, while VITEK MS identified all C. neoformans isolates after the initial FA extraction. Both systems had comparable identification rates of 37 uncommon yeast species (128 isolates), following the initial FA (Biotyper, 74.2%; VITEK MS, 73.4%) or additive FA (Biotyper, 82.0%; VITEK MS, 73.4%). CONCLUSIONS: The identification rate of most common and uncommon yeast isolates is comparable between simple FA extraction/Biotyper method and VITEK MS methods, but FA/ACN extraction is necessary for C. neoformans identification by Biotyper.

Noncatheter‑related bacteraemia due to Chryseobacterium indologenes in an immunocompetent patient.

Chryseobacterium indologenes belongs to a group of nonfermentative Gram‑negative bacilli and is an uncommon human pathogen. It causes severe infections such as septicaemia and ventilator‑associated pneumonia in immunocompromised patients or after prolonged hospitalisation. We report a case of a noncatheter‑related bacteraemia in a 22‑year‑old immunocompetent female whose blood culture showed the growth of C. indologenes, identified by Vitek GNI system (bioMerieux, France). The patient responded to treatment with ciprofloxacin. The pathogenicity and virulence factors of C. indologenes remain unclear. This case indicates that C. indologenes might cause symptomatic disease in immunocompetent persons with otherwise no associated underlying risk factors.

Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry for identification of Clostridium species isolated from Saudi Arabia

Abstract The aim of this study was to identify different Clostridium spp. isolated from currency notes from the Ha’il region of Saudi Arabia in September 2014 using MALDI–TOF-MS. Clostridium spp. were identified by Bruker MALDI–TOF-MS and compared with VITEK 2. The confirmation of the presence of different Clostridium spp. was performed by determining the sequence of the 16S ribosomal RNA gene. In this study, 144 Clostridium spp. were isolated. Among these specimens, MALDI–TOF-MS could identify 88.8% (128/144) of the isolates to the species level and 92.3% (133/144) to the genus level, whereas, VITEK 2 identified 77.7% of the (112/144) isolates. The correct identification of the 144 isolates was performed by sequence analysis of the 500 bp 16S rRNA gene. The most common Clostridium spp. identified were Clostridium perfringens (67.36%), Clostridium subterminale (14.58%), Clostridium sordellii (9%) and Clostridium sporogenes (9%). The results of this study demonstrate that MALDI–TOF-MS is a rapid, accurate and user friendly technique for the identification of Clostridium spp. Additionally, MALDI–TOF-MS has advantages over VITEK 2 in the identification of fastidious micro-organisms, such as Clostridium spp. Incorporating this technique into routine microbiology would lead to more successful and rapid identification of pathogenic and difficult to identify micro-organisms.