EUCAST rapid antimicrobial susceptibility testing (RAST) in blood cultures: Validation in 55 european laboratories

Objectives: When bloodstream infections are caused by resistant bacteria, rapid antimicrobial susceptibility testing (RAST) is important for adjustment of therapy. The EUCAST RAST method, directly from positive blood cultures, was validated in a multi-laboratory study in Europe.Methods: RAST was performed in 40 laboratories in northern Europe (NE) and 15 in southern Europe (SE) from clinical blood cultures positive for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus or Streptococcus pneumoniae. Categorical results at 4, 6 and 8 h of incubation were compared with results for EUCAST standard 16-20 h disc diffusion. The method, preliminary breakpoints and the performance of the laboratories were evaluated.Results: The total number of isolates was 833/318 in NE/SE. The number of zone diameters that could be read (88%, 96% and 99%) and interpreted (70%, 81% and 85%) increased with incubation time (4, 6 and 8 h). The categorical agreement was acceptable, with total error rates in NE/SE of 2.4%/4.9% at 4 h, 1.1%/3.5% at 6 h and 1.1%/3.3% at 8 h. False susceptibility at 4, 6 and 8 h of incubation was below 0.3% and 1.1% in NE and SE, respectively, and the corresponding percentages for false resistance were below 1.9% and 2.8%. After fine-tuning breakpoints, more zones could be interpreted (73%, 89% and 93%), with only marginally affected error rates.Conclusions: The EUCAST RAST method can be implemented in routine laboratories without major investments. It provides reliable antimicrobial susceptibility testing results for relevant bloodstream infection pathogens after 4-6 h of incubation.</p

TURKISH JOURNAL OF MEDICAL SCIENCES

Background/aim: Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry is an alternative way of identifying mycobacteria via the analysis of biomolecules. It is being increasingly used in routine microbiology practice since it permits early, rapid, and cost-effective identification of pathogens of clinical importance. In this study, we aimed to evaluate the efficacy of phenotypic identification of mycobacteria by the MALDI-TOF MS MBT Mycobacteria Library (ML) 4.0 (Bruker, Daltonics) compared to standard sequence analysis. Materials and methods: A total of 155 Mycobacterium clinical and external quality control isolates, comprising nontuberculous mycobacteria (NTM) (n = 95) and the Mycobacterium tuberculosis complex (MTC) (n = 60), were included in the study. Results: Identification by MBT ML4.0 was correctly performed in 100% of MTC and in 91% of NTM isolates. All of the MTC isolates were correctly differentiated from NTM isolates. Conclusion: Based on our results, MBT ML4.0 may be used reliably to identify both NTM and MTC

Feconomics®; a new and more convenient method, the routine diagnosis of intestinal parasiticinfections

PubMedID: 24781020Direct wet mount examination and concentration are the most commonly used methods for detecting intestinal parasites from fecal samples. Concentration methods are used when there are fewer protozoan cyst, coccidian oocyst, microsporidial spore, helminth egg, and larvae in the fecal samples. Early detection of the causative intestinal parasites plays a significant role in implementing timely and correct treatment, which relieves the patients' symptoms and also prevents recurrences. Formalin-ethyl acetate concentration (FEAC) is believed to be a gold standard method to detect most intestinal parasites. Thus, in this study, we evaluated the diagnostic value of Feconomics® [manufactured by Salubris Inc, Boston, USA. Patent application number (TR): 2010/07549] which is a simple, new, and rapid fecal concentration method for the detection of the intestinal parasites in human beings. We also compared the FEAC with Feconomics® and direct wet mount examination. A total of 918 fecal samples were collected from the patients suspected to have intestinal parasitic infection. Samples were examined with the direct wet mount, FEAC, and Feconomics® methods. Different parasite species 15.9 % (146/918) with Feconomics®, 13.3 % (122/918) with FEAC, and 9.8 % (90/918) with direct wet mount examination, Feconomics®>FEAC>direct wet mount examinations were detected. They were statistically compared considering FEAC as the gold standard for parasitological diagnosis; the sensitivity and specificity of Feconomics® were calculated as 96 and 97 %, respectively. Blastocystis hominis was found to be the most common parasite, followed by Giardia lamblia with direct wet mount examination, FEAC, and Feconomics® methods. Feconomics® proved to be better than not only FEAC in concentrating parasite egg and cyst forms as well as in maintaining characteristic morphology but it is also better in direct wet mount examination. Feconomics® eliminates the need for centrifugation by using absorbent beads that help the homogenization and concentration of the sample. Feconomics® in this study was considerably better than FEAC in detecting the trophozoites of Giardia lamblia. We suggest that Feconomics® be used for the routine diagnosis of intestinal parasitic infection in rural areas of developing countries due to the fact that a centrifuge is not required and it eliminates large stool particles. © 2014 Springer-Verlag

Evaluation of the Bruker Matrix-Assisted Laser Desorption–Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) System for the Identification of Clinically Important Dermatophyte Species

PubMedID: 25971934Dermatophytes can invade the stratum corneum of the skin and other keratinized tissues and are responsible for a broad diversity of diseases of skin, nails and hair. Although the standard identification of dermatophytoses depends on macroscopic and microscopic characterization of the colonies grown on special media, there are a number of limitations owing to intraspecies morphological variability, atypical morphology or interspecies morphological similarity which entails improvement in the identification methods. Matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a novel method which proved to be effective for rapid and reliable identification of dermatophytes grown in cultures when compared to conventional methods. We evaluated the performance of Bruker MALDI-TOF MS System (Bruker Daltonics, Germany) for identification of clinically relevant dermatophytes. In order to increase the identification capacity of the system, we created supplemental spectral database entries using ten reference dermatophyte strains (ten species in two genera). The utility of the generated database was then challenged using a total of 126 dermatophytes (115 clinical isolates and 11 additional reference strains). The results were evaluated by both manufacturer-recommended and lowered cutoff scores. MALDI-TOF MS provided correct identification in 122 (96.8 %) and 113 (89.7 %) of the isolates with the lowered scores and using the supplemented database, respectively, versus 65 (51.6 %) and 17 (13.5 %) correct identifications obtained by the unmodified database and recommended scores at the genus and species levels, respectively. Our results support the potential utility of MALDI-TOF MS as a routine tool for accurate and reliable identification of dermatophytes. © 2015, Springer Science+Business Media Dordrecht

Lateral flow assay for rapid differentiation of Mycobacterium tuberculosis complex and 97 species of mycobacteria other than tuberculosis grown in Löwenstein-Jensen and TK-SLC medium

Background: Mycobacterial antigen MPB64 is a secretory protein specific for Mycobacterium tuberculosis complex. A lateral flow immunochromatographic assay (ICA) is a method used for the rapid differentiation of M. tuberculosis complex. Aim: We aimed to evaluate the performance of ICA in rapid differentiation of M. tuberculosis complex from 97 Mycobacterium species other than tuberculosis (MOTT), which are grown in Lφwenstein-Jensen and TK-selective (SLC) medium. Materials and Methods: The study was performed in our laboratory between January 2009 and January 2010. A total of 394 isolates consisting of reference strains of 34 M. tuberculosis from World Health Organization (WHO) collection, 97 different MOTT bacilli, 7 Mycobacterium bovis BCG substrains and total 256 clinical Mycobacterium isolates were tested by ICA, which is based on anti-MPB64 monoclonal antibodies. All the strains were inoculated onto a TK-SLC (selective) medium and Lφwenstein-Jensen medium. TK-SLC is a new rapid mycobacterial culture medium that indicates mycobacterial growth by colour change. Results: The growth of mycobacterial strains was observed in 10-12 days on TK-SLC medium. ICA test was performed in 15 minutes. All strains belonging to M. tuberculosis complex group were found positive and all MOTT species were found negative on ICA slides. The results were confirmed with nucleic acid amplification by polymerase chain reaction (PCR) using primers specific for M. tuberculosis complex. Conclusion: With the additive effect of growth on TK-SLC medium in 10-12 days, the mycobacterial antigen MPB64 is a very useful and specific tool in rapid differentiation of M. tuberculosis and MOTT grown in culture

Six-year distribution pattern of hepatitis C virus in Turkey: A multicentre study

Hepatitis C infection is a public health problem. The aim of this retrospective study was to determine the distribution of hepatitis C virus (HCV) genotypes in seven regions of Turkey, by evaluating 7002 patients with chronic HCV in a six-year period. During the 2009–2014 period, serum/plasma samples from 7002 new consecutive HCV RNA positive patients were collected. The female patients were 3867 (55.2%). The genotype distribution of HCV patiens was evaluated by ages and years. Statistical analysis was performed by using the Mann–Whitney test and the ?2 analysis. During the six-year period, genotype 1b was the most common genotype (67.7%) followed by untypeable genotype 1 (7.7%), genotype 4 (7.3%) and genotype 3 (6.7%). In 2014, genotype 3 was the second most common one (11.3%) and genotype 4 was the third most common one (9.8%). In the group with &lt;25 years old patients, genotype 1b was most common (78.48%, 62/79) between the years of 2009 and 2011, whereas genotype 3 (34.8%, 86/247), between the years of 2012 and 2014. Genotype 1b was the most common in the groups between 26 and 35 years, 36 and 45 years, 46 and 55 years, 56 and 65 years. The rate of genotype 3 was increased from 4.78% to 10.06% and the rate of genotype 4 was increased from 1.3% to 3.84%, from 2009–2011 to 2012–2014. In recent years, genotypes 3 and 4 have gained importance. New therapeutic strategies and survey studies may be required for the modified HCV genotype pattern. © 2016 The Author(s). Published by Taylor & Francis