Comparison of Two Methods and Three End Points in Determination of In Vitro Activity of Micafungin against Aspergillus spp.

We investigated the in vitro activity of micafungin against clinical Aspergillus isolates (n = 37) (Aspergillusfumigatus [n = 21], Aspergillusflavus [n = 14], and Aspergillus niger [n = 2]) by using NCCLS M38A microdilution and an investigational disk diffusion assay. Microdilution assay results were evaluated by using the end points of a MIC-2 (measured in micrograms per milliliter) and minimum effective concentration (MEC, measured in micrograms per milliliter; the lowest concentration of micafungin that produces short and aberrant hyphal branchings microscopically). Disk diffusion results were interpreted by measuring the zone(s) of inhibition (ZOI, measured in millimeters). Micafungin proved to be similarly active against all Aspergillus species tested. At 24 h, MIC-2s and MECs were identical. At 48 h, however, MIC-2s increased unpredictably, leading to the loss of a consistent correlation between the two end points. MECs and ZOI remained consistent and correlated at both reading times, suggesting their use as relevant end points in susceptibility testing of micafungin against Aspergillus. All Aspergillus isolates yielded intrazonal growth on disk diffusion agar plates. The intrazonal colonies contained short, aberrant hyphal branchings microscopically. The in vivo significance of these findings remains to be further investigated

Antimicrobial Susceptibilities of Clinical Nocardia Isolates Identified By 16S Rrna Gene Sequence Analysis

Nocardia species are ubiquitous in the environment and responsible for various human infections such as pulmonary, cutaneous, central nervous system and disseminated nocardiosis. Since the clinical pictures and antimicrobial susceptibilities of Nocardia species exhibit variability, susceptibility testing is recommended for every Nocardia isolates. The aims of this study was to determine the antimicrobial susceptibilities of Nocardia clinical isolates and to compare the results of broth microdilution and disc diffusion susceptibility tests. A total of 45 clinical Nocardia isolates (isolated from 17 respiratory tract, 8 brain abscess, 7 pus, 3 skin, 3 conjunctiva, 2 blood, 2 tissue, 2 pleural fluid and 1 cerebrospinal fluid samples) were identified by using conventional methods and 16S rRNA gene sequence analysis. Susceptibility testing was performed for amikacin, ciprofloxacin, ceftriaxone, linezolid and trimethoprim-sulfamethoxazole (TMP-SMX) by broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) criteria recommended in 2011 approved standard (M24-A2) and disk diffusion method used as an alternative comparative susceptibility testing method. Among the 45 Nocardia strains, N.cyriacigeorgica (n: 26, 57.8%) was the most common species, followed by N.farcinica (n: 12, 26.7%), N.otitiscaviarum (n: 4, 8.9%), N.asteroides (n: 1, 2.2%), N.neocaledoniensis (n: 1, 2.2%) and N.abscessus (n: 1, 2.2%). Amikacin and linezolid were the only two antimicrobials to which all isolates were susceptible for both broth microdilution and disk diffusion tests. In broth microdilution test, resistance rates to TMP-SMX, ceftriaxone and ciprofloxacin were found as 15.6%, 37.8% and 84.4% respectively, whereas in the disk diffusion test, the highest resistance rate was observed against ciprofloxacin (n: 33, 73.3%), followed by TMP-SMX (n: 22, 48.9%) and ceftriaxone (n: 15, 33.3%). In both of these tests, N.cyriacigeorgica was the species with the highest resistance to ciprofloxacin (n: 25, 96.2%). When the susceptibility test results were compared, amikacin (kappa=1), linezolid (kappa=1), and ceftriaxone (kappa=0.903) showed very good agreement, whereas ciprofloxacin showed good agreement (kappa=0.672). For TMP-SMX no agreement was found between the two test methods (kappa=0.092). In conclusion, due to the identification of different species with molecular methods and increased frequency of Nocardia infections in recent years, in vitro susceptibility testing for Nocardia species is important to guide the appropriate antimicrobial treatment.WoSScopusTr-Dizi

An Automated Image Analysis System Can be Beneficial in Preclassification of Leucocytes in Children with Hematological Disease.

This study was aimed to evaluate the analytical performance of an automated image analysis system (a pilot model of Diff Master™ Octavia) for the preclassification of leucocytes in children with hematological disease. Manual microscopy performed by pediatric hematologists was used as the reference method. Five mature cell class and blasts were evaluated. Diff Master Octavia correctly preclassified 87.4% of all leucocytes with a high reproducibility. The overall accuracy was found to be 93.0%. Clinical sensitivity was 97.7% and specificity was 76.0%. The average time per slide for Diff Master™ Octavia was 2.3 min lower than that of manual method. Our results indicated that the Diff Master™ Octavia can detect and preclassify leucocytes accurately; therefore, it can be used as an efficient and fast method in pediatric hematology routine. J. Clin. Lab. Anal. 25:71–75, 2011. © 2011 Wiley‐Liss, Inc.Wo

Evaluation Of Methicillin-Resistant Staphylococcus Aureus Bacteremia And Comparison Of Prognosis According To Vancomycin Mic Values: Experience Of The Last Ten Years

Hospital acquired methicillin-resistant Staphylococcus aureus (MRSA) infections are important health problems. Mortality and morbidity rates associated with MRSA infections are increasing with mortality rates being higher for MRSA bacteremia than the other clinical presentations of MRSA infections. Initiation of treatment immediately and use of appropriate antibacterial agents may lead to better clinical outcomes in MRSA bacteremia. The aims of this study were to evaluate the treatment and clinical outcomes of patients with MRSA bacteremia in a tertiary care hospital in Ankara, Turkey. Two hundred forty seven MRSA strains isolated from blood cultures at Hacettepe University Faculty of Medicine, Clinical Microbiology Laboratory between January 2000-December 2010, were evaluated retrospectively. Demographic characteristics, duration of bacteremia, types and duration of antibiotic treatment, presence of other pathogens and all other necessary information were collected from patients' registry. One hundred eighty four patients who had clinically significant bacteremia were analyzed. The mean age of the patients was 55 17 years, of them 44.6% were female and 55.4% were male. The median length of hospital stay was 61 days. The median duration for the development of MRSA bacteremia from the time of admission was 23 days. Overall mortality rate was 54.9%, and mortality rate due to MRSA bacteremia was 19%. The rate of treatment success was 81%. There were 3 (1.6%) patients with vancomycin MIC value of 0.5 mg/L, 140 (76.1%) patients with 1 mg/L and 41(22.3%) patients with 2 mg/L. The median duration from the time of MRSA bacteremia detection to the time of death was shorter in unsuccessfully treated group than successfully treated group (7 days vs. 30 days, p<0.001). Thirty days mortality rate was higher in unsuccessfully treated group than successfully treated group (94.3% vs. 50.7%, p<0.001). The median time interval between positive and negative cultures was 9.5 days. Number of patients with MRSA bacteremia had been decreasing for the last five years (36 patients in 2006, 18 in 2007, 16 in 2008, 12 in 2009 and one in 2010). In multivariate logistic regression analysis, it was shown that, intubation (OR: 5.086, 95% CI: 2.094-12.351; p<0.001) and malignancy (OR: 2.789, 95% Cl: 1.185-6.564; p=0.019) were independent risk factors for mortality. In this study, it was shown that mortality rate was high in MRSA bacteremia and high MIC value was not an independent risk factor for mortality. It was also noted that when there was no clinical response to vancomycin, the therapy should be changed immediately. To decrease MRSA bacteremia rates in the hospital adherence to rules of infection control and prevention proved to be important factors.WoSScopusTr-Dizi

MEMS biosensors for detection of methicillin resistant Staphylococcus aureus

This review presents the current state of the conventional methods, microfluidic based biosensors, and the commercial products used in the detection of methicillin resistant Staphylococcus aureus (MRSA), which is one of the most important threats of nosocomial infections in many parts of the world. The early detection of MRSA in the specimens of the patients is important to enable the appropriate treatment, to decrease morbidity and mortality rates, and to manage control actions in the healthcare units. Thus, rapid and inexpensive diagnostic systems with high sensitivity and specificity are essential to prevent MRSA to be an emerging public health threat. The design and fabrication of new diagnostic systems necessitates working in collaboration between different disciplines to make new challenges in the field of clinical diagnosis and to meet the demands of clinicians. It is certain that in the near future. MEMS and nanotechnology based detection methods will take the place of current methods in clinical diagnosis. The evaluation of new trends for specificity, sensitivity, cost effectiveness, disposability, low weight, ease of use, and facile access should be taken into consideration

Neisseria meningitidis W135, Turkey

We describe the first case of Neisseria meningitidis W135 meningitis in Turkey. The strain was genotypically unrelated to the clone (W)ET-37, isolated from Hajj pilgrims in 2000

Accurate Diagnosis of Pseudomonas luteola in Routine Microbiology Laboratory: On the Occasion of Two Isolates

Pseudomonas luteola which was previously known as Chryseomonas luteola; is a gram-negative, non-fermentative, aerobic, motile, non-spore-forming bacillus. It is frequently found as a saprophyte in soil, water and other damp environments and is an opportunistic pathogen in patients with underlying medical disorders or with indwelling catheters. It has been reported as an uncommon cause of bacteremia, sepsis, septic arthritis, meningitis, endocarditis, and peritonitis. Thus, early and accurate identification of this rare species is important for the treatment and also to provide information about the epidemiology of P.luteola infections. This report was aimed to draw attention to the accurate identification of P.luteola in clinical samples, upon the isolation and identification in two cases in the medical microbiology laboratory of a university hospital. In February 2011, a 66-year-old man, with chronic obstructive pulmonary disease, coronary artery disease and aplastic anemia, was admitted to our hospital due to progressive dyspnea. A chest tube was inserted on the 20th day of admission by the reason of recurrent pleural effusion. Staphylococcus aureus and a non-fermentative gram-negative bacillus (NFGNB) with wrinkled, sticky yellow colonies were isolated from the pleural fluid sample obtained on the 9th day following the insertion of the chest tube. In February 2012, a 7-year-old male cystic fibrosis patient who had no signs and symptoms of acute pulmonary exacerbation was admitted to the hospital for a routine control. This patient had chronic colonization with Pseudomonas aeruginosa and S.aureus and his sputum sample obtained at this visit revealed isolation of P.aeruginosa, S.aureus, Aspergillus fumigatus and a wrinkled, sticky yellow NFGNB. Both of these NFGNB were identified as P.luteola by the Phoenix automated microbial identification system (BD Diagnostics, USA). To evaluate the microbiological characteristics of these two isolates, the strains were further analysed by VITEK MS (bioMerieux, France) and Microflex LT mass spectrometer (Bruker Daltonics, Germany). Both of the MALDI-TOF-MS systems identified the isolates as P.luteola and 16S rRNA gene sequencing (ABI PRISM 3100, Applied Biosystems, USA) also confirmed the identification. The strains had wrinkled, sticky yellow colonies which were oxidase-negative, catalase-positive and non-fermentative. The Gram stained smears of the colonies revealed clusters of gramnegative bacilli probably embedded into a biofilm matrix. Since there are no accepted standards for testing the antibiotic susceptibility of P.luteola strains, the standards determined by CLSI for "other non-Enterobacteriaceae" (non-fermentative bacteria excluding P.aeruginosa, Acinetobacter spp., Burkholderia cepacia, B.mallei, B.pseudomallei and Stenotrophomonas maltophilia) were used for the susceptibility testing. Gradient MIC method (E-Test, bioMerieux, France) revealed that the isolates were susceptible to gentamicin, piperacillin-tazobactam, ceftazidime, cefepime, meropenem, colistin and levofloxacin. Accurate and prompt identification of P.luteola which is identified as a rare pathogen in serious cases is of critical importance since it has been suggested that this organism is likely to become more frequent as a nosocomial pathogen since the interventional processes increase in current medical practice. This report supported that Phoenix automated phenotypic identification system (BD Diagnostics, USA) and the two MALDI-TOF-MS based systems (VITEK MS and Bruker Microflex LT mass spectrometer) were successfull in the accurate identification of P.luteola

Antimicrobial Activity of Ankaferd Blood Stoppera (R) Against Nosocomial Bacterial Pathogens

The aim of this study is to investigate the in vitro antimicrobial activity of Ankaferd Blood StopperA (R) against methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus species, Escherichia coli, Pseudomonas species, Acinetobacter species and Klebsiella species of nosocomial origin. Ankaferd inhibited growth in 72.4% to 100% of the bacteria tested, depending on the type of the isolate. As a result, it can be stated that Ankaferd inhibits the in vitro growth of nosocomial bacteria. This is a novel, important finding since severe hospital infections coexist with many hemostatic disorders, and the use of Ankaferd may increase hemostatic potential in such clinical conditions

Erythromycin-resistant Streptococcus pneumoniae: phenotypes, genotypes, transposons and pneumococcal vaccine coverage rates

Purpose. To assess the antibiotic resistance, transposon profiles, serotype distribution and vaccine coverage rates in 110 erythromycin-resistant S. pneumoniae clinical isolates