In vitro activity of tedizolid against 43 species of Nocardia species.

The purpose of the present study was to evaluate the in vitro activity of tedizolid against several clinically significant species of Nocardia by comparing with that of linezolid. A total of 286 isolates of Nocardia species, including 236 clinical isolates recovered from patients in Japan and 50 strains (43 species) purchased from NITE Biological Resource Center, were studied. Antimicrobial susceptibility testing was performed using the broth microdilution method. For the 286 Nocardia isolates, the minimal inhibitory concentration (MIC)50 and MIC90 values of tedizolid were 0.25 and 0.5 µg/ml, and those of linezolid were 2 and 2 µg/ml, respectively. The distribution of the linezolid/tedizolid ratios (MICs of linezolid/MICs of tedizolid) showed that tedizolid had four- to eight-fold higher activity than linezolid in 96.1% (275/286) of Nocardia isolates. Both the tedizolid and linezolid MIC90 values for Nocardia brasiliensis were two-fold higher than those for the other Nocardia species. Both tedizolid and linezolid had low MIC values, 0.25-1 µg/ml and 0.5-4 µg/ml, respectively, even against nine isolates (five species) that were resistant to trimethoprim/sulfamethoxazole. One Nocardia sputorum isolate showed reduced susceptibility to tedizolid (4 µg/ml). Bioinformatics analysis suggests different resistance mechanisms than the oxazolidinone resistance seen in enterococci and staphylococci.

Nocardia sputorum sp. nov., an actinobacterium isolated from clinical specimens in Japan.

Two novel actinobacteria, designated IFM 12276T and IFM 12275, were isolated from clinical specimens in Japan, and their taxonomic positions were investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strains IFM 12276 T and IFM 12275 have completely identical 16S rRNA gene sequences and were closely related to members of the genus Nocardia. The highest 16S rRNA gene sequence similarity was observed to Nocardia beijingensis (99.6 %) and Nocarida sputi (99.6 %), followed by Nocardia niwae (99.3 %) and Nocardia araoensis (99.3 %). The whole-cell hydrolysates of strains IFM 12276T and IFM 12275 contained meso-diaminopimelic acid, arabinose and galactose. The acyl type of muramic acid was N-glycolyl. The predominant isoprenoid quinone was MK-8(H4, ω-cycl.) and the principal polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. Strains IFM 12276T and IFM 12275 contained mycolic acids that co-migrated with those from the type strain of N. niwae. These chemotaxonomic features corresponded to those of the genus Nocardia. Meanwhile, the differences in some phenotypic characteristics, along with the results of average nucleotide identity and digital DNA-DNA hybridization analyses, indicated that strains IFM 12276 T and IFM 12275 should be distinguished from the recognized species of the genus Nocardia. Therefore, these strains represent a novel species of the genus Nocardia, for which the name Nocardia sputorum sp. nov. is proposed. The type strain is IFM 12276T (=NBRC 115477T=TBRC 17096T).

Identification and antimicrobial susceptibility profiles of Nocardia species clinically isolated in Japan.

The aims of the present study were to profile the antimicrobial susceptibility patterns of a diverse range of Nocardia species isolated in Japan, and to determine the ability of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for species/complex identification. Identification of 153 clinical isolates was performed by full-length 16S rRNA gene sequencing as a reference method to evaluate the usefulness of MALDI-TOF MS identification. Antimicrobial susceptibility testing (AST) for 14 antibiotics was performed using the broth microdilution method against 146 of the isolates. Among the total 153 clinical isolates, Nocardia farcinica complex (25%) was the most common species, followed by Nocardia cyriacigeorgica (18%), Nocardia brasiliensis (9%), Nocardia nova (8%), and Nocardia otitidiscaviarum (7%). Among 150 isolates identified to the species/complex level by 16S rRNA gene sequencing, MALDI-TOF MS with the use of a supplemental Nocardia library (JMLD library ver.ML01) correctly identified 97.3% (n = 146) to the species/complex level and 1.3% (n = 2) to the genus level. Among the 146 Nocardia isolates that underwent AST, the susceptibilities were 100% to linezolid, 96% to amikacin, 94% to trimethoprim-sulfamethoxazole, and 76% to imipenem. None of the trimethoprim-sulfamethoxazole-resistant isolates carried either plasmid-mediated sulfonamide-resistant genes (sul1, sul2) or trimethoprim-resistant genes (dfrA).

Validation of MALDI-TOF MS devices in reanalysis of unidentified pathogenic bacteria detected in blood cultures.

In hospital microbial laboratories, morphological and biochemical analyses are performed to identify pathogenic microbes;however, these procedures lack rapidity and accuracy. Recently, Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) has been clinically utilized, and is expected to enable rapid and accurate microbial identification. We aimed to validate two MALDI-TOF MS devices available in Japan: the VITEK-MS (BioMérieux) and the Microflex LT (Bruker Daltonics). Clinically isolated bacteria, 100 samples in all, detected in blood cultures but incompletely identified by conventional procedures, were reanalyzed using the two devices. The VITEK-MS and Microflex LT, respectively, identified 49% (49/100) and 80% (80/100) of the tested bacteria at the species level, as well as 96% (96/100) and 95% (95/100) at the genus level. Among those reidentified strains, 26% (26/100) at the species level and 88% (88/100) at the genus level were concordant with each other, though three strains were unmatched. Moreover, four bacterial strains were unable to be identified using the VITEK-MS, versus five using the Microflex LT. MALDI-TOF MS devices can provide more rapid and accurate bacterial identification than ever before;however, the characteristics of each system were slightly different;therefore, it is necessary to understand the difference in performance of MALDI-TOF MS models.

Calcitonin levels by ECLIA correlate well with RIA values in higher range but are affected by sex, TgAb, and renal function in lower range.

Calcitonin (CT) is a marker for both initial diagnosis and monitoring of patients with residual or recurrent medullary thyroid carcinoma (MTC). In Japan, serum CT had been measured by radioimmunoassay (RIA) until recently. Electrochemiluminescence immunoassay (ECLIA) became commercially available in 2014, and this technique is now the only method used to examine CT concentration. The purposes of this study were to investigate the correlations between the CT concentration measured with ECLIA (ECLIA-CT) and RIA (RIA-CT) and to explore the clinical characteristics of patients with elevated ECLIA-CT. CT concentrations of 348 sera samples from 334 patients with various thyroid disorders including nine MTC were measured using both assays. The correlation analysis revealed an excellent correlation between ECLIA-CT and RIA-CT among the cases with CT level >150 pg/mL by both assays (rs = 0.991, p < 0.001). However, 63% of all samples exhibited undetectable ECLIA-CT, while their RIA-CTs were measured between 15 and 152 pg/mL. The ECLIA-CTs in all patients who underwent total thyroidectomy for non-MTC showed low concentrations. High ECLIA-CT was observed in patients with MTC or pancreas neuroendocrine tumor. ECLIA-CT was also increased in 14 other male patients with non-MTC, including four with renal failure. Multivariate logistic regression analysis showed that male sex, negative TgAb, and lower estimated glomerular filtration rate were independent factors to predict detectable ECLIA-CT (≥0.500 pg/mL). These results indicate that ECLIA-CT correlates well with RIA-CT in higher range and is affected by sex, TgAb, and renal function.

Expression of activation-induced cytidine deaminase enhances the clearance of pneumococcal pneumonia: evidence of a subpopulation of protective anti-pneumococcal B1a cells.

We describe a protective early acquired immune response to pneumococcal pneumonia that is mediated by a subset of B1a cells. Mice deficient in B1 cells (xid), or activation-induced cytidine deaminase (AID(-/-) ), or invariant natural killer T (iNKT) cells (Jα18(-/-) ), or interleukin-13 (IL-13(-/-) ) had impaired early clearance of pneumococci in the lung, compared with wild-type mice. In contrast, AID(-/-) mice adoptively transferred with AID(+/+) B1a cells, significantly cleared bacteria from the lungs as early as 3 days post infection. We show that this early bacterial clearance corresponds to an allergic contact sensitivity-like cutaneous response, probably due to a subpopulation of initiating B1a cells. In the pneumonia model, these B1a cells were found to secrete higher affinity antigen-specific IgM. In addition, as in contact sensitivity, iNKT cells were required for the anti-pneumococcal B1a cell initiating response, probably through early production of IL-13, given that IL-13(-/-) mice also failed to clear infection. Our study is the first to demonstrate the importance of AID in generating an appropriate B1a cell response to pathogenic bacteria. Given the antibody affinity and pneumonia resistance data, natural IgM produced by conventional B1a cells are not responsible for pneumonia clearance compared with the AID-dependent subset.

[Current situation and the role of department of clinical laboratory medicine on the Fukushima Health Management Survey Project for risk of thyroid cancer].

Since the accident at Fukushima Daiichi nuclear power plant after the Great East Japan Earthquake on March 11, 2011, large quantities of radionuclides have leaked from Fukushima Daiichi Nuclear Plant into the surrounding environment. Fukushima Prefecture started the Fukushima Health Management Survey Project, including thyroid ultrasound examinations to screen for thyroid cancer, covering approximately 360,000 residents aged 0 to 18 years at the time of the nuclear accident. Doctors and medical technicians in the Department of Clinical Laboratory Medicine of Fukushima Medical University Hospital are participating in this program as administrators, examiners, and instructors. In the first preliminary survey from October, 2011 to March, 2012 for residents in highly contaminated areas, A2 judgment, defined as cysts of < or = 20.0 mm or nodules < or = 5.0 mm in diameter, and B judgment, defined as cysts or nodules larger than A2 were found in 35.8% and 0.5%, respectively. In second preliminary survey until March, 2013, A2 and B judgments were identified in 44.6% and 0.7% of residents in intermediately contaminated areas. A secondary examination for young residents who were judged as B or C identified 28 cases of malignancy or suspected malignancy. The radiation dose, age at diagnosis, diameters and tissue characteristics of the thyroid cancer suggest that the thyroid cancer found in Fukushima had already occurred before the earthquake. Since this project should be continued for several decades, we would like to ask for your support and cooperation over the long term.

[Activities for laboratory medicine support after the Great East Japan Earthquake by the Japanese Society of Laboratory Medicine].

The Great East Japan Earthquake caused a tragic tsunami and resulted in serious damage to north region of Japan on March 11, 2011. The Japanese Society of Laboratory Medicine, JSLM launched an ad hoc Committee to support Laboratory Medicine affairs in the affected area. We expected that laboratory testing demands would increase during the weeks following the disaster. We decided to support the use of Point-of-Care Testing. Many POCT devices use battery-powered analyzers. This is definite advantage for their use in areas with limited access to power and water supplies. We contacted many companies about the possibility of providing POCT devices, IVD reagents and/or any laboratory supplies including disposable materials. Finally, forty companies agreed to support this project and we received list of reagents materials for more than one hundred IVD tests. We entered this information on our web site and continued to update it as additional support was received. Once a request of support was received, communication were made to confirm the amount of material, the method of shipping/receipt and if any specific training that would be required for its use at the testing site. Also, we dispatched volunteer Medical Technologists for eight weeks to assist in the laboratory work. Some of the crucial points in recruiting volunteer laboratory professions are expenses and accommodations. We prepared not only accommodations but also transportation methods and covered all expenses including insurance and meals. Our relief activities have shown that Laboratory Medicine and Medical Technologists are useful in disaster-affected area.

[Various troubles in the Central Clinical Laboratory (violence, others) and actions to be taken].

We need to attend to a patient face to face in the physiological function testing room and the central blood-drawing room of the central clinical laboratory in a hospital. Recently, there have been some problems and troubles experienced by medical staff because patients may have had some over-expectations regarding our medical service and their sense of entitlement may have been unrealistic. We report some problems experienced in our Central Clinical Laboratory and hospital, and describe some solutions. If a medical staff member gets into trouble with a patient because of some difference in awareness between him/her and the patient, we should take prompt action regarding these claims and be considerate to the patient. However, we have to take a tough stance against some severe cases, for example violence and intemperate language directed toward medical staff. One of the most important things is to investigate complaints against us, and, through this, keep on improving. Another important thing is to disseminate information among central clinical laboratory teams liaising with nursing and other departments. Therefore, we can establish a good trusting relationship between patients and staff, and consequently our patient service will improve.

[Utility of Hybrisep in the diagnosis of blood stream infection].

Hybrisep is an in situ hybridization (ISH) method to detect phagocytosed bacteria in peripheral blood neutrophils and macrophages. We report 10 actual clinical cases tested using Hybrisep with new DNA probes, and the data were compared to the actual blood culture results. A normal Hybrisep strategy employs 5 DNA probes to detect the following bacterial DNA: "SA" probe for S. aureus, "SE" for S. epidermidis, "PA" for P. aeruginosa, "EF" for E. faecalis, and "EK" for E. coli, E. cloacae, and K. pneumoniae. Six newly designed DNA probes were used in this study: "GB" probe for 49 common bacteria, "SP" for S. pneumoniae, "BF" for B. fragilis, "HI" for H. influenzae, "GC" for Candida species, and "CA" for C. albicans. Three cases were positive on ISH, but all their blood cultures were negative. One case showed a positive blood culture, but was negative on ISH. In another 6 cases, both were negative. We postulated that empirical therapy of antibiotics resulted in only positive ISH. Cases only showing a positive outcome on blood culture might be due to a diminished phagocytic function during patients' severe disease conditions. In conclusion, ISH with Hybrisep has clinical advantages such as being able to defect causative pathogens even after the use of antibiotics, and facilitates more rapid identification than routinely performed bacterial cultures only.

[Adaptations to the incidental cases encountered at the division of clinical laboratory].

We analyzed 4 cases that were not determined as incidents and another 7 cases determined as incidents, found at the department of clinical laboratory of us from April 2009 to March 2010. The former cases were, excess values of LD, and Cl, and glucose leveled as 0 mg/dl incorrectly, and misdirected blood samples at the ER. Our routine equipment and sample flow did not detect these false values. Resetting for auto dilution system and secondary check by every worker were reconsidered for these measurements. Antiseptic drug usage was notified by clinicians, and actually affected to the excessive Cl value. Real incidents were, two unprocessed samples, leakage of a sample, missing processes that caused delay of clinical practice, mixed up sample labels, a lost narcotic patch during cardiac ultrasonography. A lack of checking, carelessness, and accidental mistakes were reevaluated and reminded for workers on the duties. Also inadequate pharmaceutical knowledge and responsibilities of this section might severely affect on these lessons. Efforts were taken so that all workers shared the accurate information. Code blue cases are defined here as those of life-threatening events and sudden vital changes occurred in highest emergency, involve all health care workers, patients, and families. It is very important here to keep regular trainings for workers to cope with such events as well as preemptive assessments on environment and underlying risks in our laboratory. In line with the continuous advances in clinical medicine, medical safety managements are growing issues. To achieve safer environment and minimize various type of risks in the hospital, these incidents are to be assessed and reported regularly.