Automated preparation for identification and antimicrobial susceptibility testing: evaluation of a research use only prototype,the BD Kiestra IdentifA/SusceptA system

ObjectiveThe current BD Kiestra? total laboratory automation (TLA) system automates specimen inoculation, incubation, and digital visualization of cultures prior to initiation of manual or semi-automated identification (ID) and antimicrobial susceptibility testing (AST). The current study aimed to compare the performance, in a clinical setting, of a fully automated research-use-only prototype, BD Kiestra? IdentifA/SusceptA (automated system), to our current BD Kiestra? TLA which utilizes manual or semi-automated IDs and ASTs (current system).MethodsClinical samples yielding significant growth after processing by the BD Kiestra? TLA were tested in parallel for ID and AST by both systems. IDs and ASTs were determined by Bruker matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and BD Phoenix, respectively, with data stored and managed in the BD EpiCenter?. The automated system used a common inoculum preparation for both tests, whereas the current system used separate inocula. Results were compared to assess agreement between the systems.ResultsOn initial testing, 89% of IDs (466/523) and 92.4% of IDs (484/523) for the automated and current ID systems, respectively, yielded acceptable MALDI-TOF log scores of ≥1.7. On repeat testing, the respective acceptable scores were 97.1% (508/523) and 98.1% (513/523). For initial ASTs, the automated and current systems yielded 97.5% categorical agreement for 7325 drug–organism tests. After omitting discrepant MICs that differed by only one dilution and categorical discrepancies that were not reproducible, 0.2% unresolved discrepancies remained thus (99.8% categorical agreement).ConclusionsThe automated prototype is suitable for development into technology that will provide clinical microbiology laboratories with significant advantages such as improved efficiency, standardization, reproducibility, reduced technical error and greater safety.     

Functional Assessment of TSC2 Variants Identified in Individuals with Tuberous Sclerosis Complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations in the TSC1 or TSC2 genes. The TSC1 and TSC2 gene products, TSC1 and TSC2, form a complex that inhibits the mammalian target of rapamycin (mTOR) complex 1 (TORC1). Here, we investigate the effects of 78 TSC2 variants identified in individuals suspected of TSC, on the function of the TSC1–TSC2 complex. According to our functional assessment, 40 variants disrupted the TSC1–TSC2‐dependent inhibition of TORC1. We classified 34 of these as pathogenic, three as probably pathogenic and three as possibly pathogenic. In one case, a likely effect on splicing as well as an effect on function was noted. In 15 cases, our functional assessment did not agree with the predictions of the SIFT amino acid substitution analysis software. Our data support the notion that different, nonterminating TSC2 mutations can have distinct effects on TSC1–TSC2 function, and therefore, on TSC pathology.     

High incidence of subclinical peripheral neuropathy in myelitis with hyperIgEaemia and mite antigen-specific IgE (atopic myelitis): an electrophysiological study

OBJECTIVE: To study subclinical involvement of the peripheral nerves in myelitis with hyperIgEaemia and mite antigen-specific IgE (atopic myelitis: AM). MATERIAL AND METHODS: We carried out a nerve conduction study of the median, ulnar, tibial, and sural nerves in 21 patients with AM and in 28 patients with clinically definite or laboratory-supported definite multiple sclerosis (MS). RESULTS: The patients with AM showed a significantly higher frequency of abnormal records than the MS patients in the sensory nerve conduction study (52.4% vs. 14.3%, p = 0.0106). The frequency of abnormal records in the motor nerve conduction study in AM patients was twice as high as in MS patients (38.1% vs. 17.9%), but the difference was not statistically significant. Abnormality in the F-wave-evoked frequency in the median nerve was also significantly more common in AM patients than in MS patients (57.9% vs. 10.7%, p = 0.0016). CONCLUSIONS: These findings suggest that subclinical peripheral neuropathy is frequent in patients with AM.     

Combined Deletion of Vhl and Kif3a Accelerates Renal Cyst Formation

A subset of familial and sporadic clear cell renal cell carcinomas (ccRCCs) is believed to develop from cystic precursor lesions. Loss of function of the von Hippel-Lindau tumor suppressor gene (VHL) predisposes renal epithelial cells to loss of the primary cilium in response to specific signals. Because the primary cilium suppresses renal cyst formation, loss of the cilium may be an initiating event in the formation of ccRCC. To test this hypothesis, we analyzed the consequences of inducible renal epithelium–specific deletion of Vhl together with ablation of the primary cilium via deletion of the kinesin family member 3A (Kif3a) gene. We developed a microcomputed tomography–based imaging approach to allow quantitative longitudinal monitoring of cystic burden, revealing that combined loss of Vhl and Kif3a shortened the latency of cyst initiation, increased the number of cysts per kidney, and increased the total cystic burden. In contrast with findings in other cystic models, cysts in Kif3a mutant mice did not display accumulation of hypoxia-inducible factor 1-α (HIF1α), and deletion of both Hif1a and Kif3a did not affect cyst development or progression. Vhl/Kif3a double mutation also increased the frequency of cysts that displayed multilayered epithelial growth, which correlated with an increased frequency of misoriented cystic epithelial cell divisions. These results argue against the involvement of HIF1α in promoting renal cyst growth and suggest that the formation of simple and atypical renal cysts that resemble ccRCC precursor lesions is greatly accelerated by the combined loss of Vhl and the primary cilium.     

Scintigraphic evaluation of gallbladder motor functions in H pylori positive and negative patients in the stomach with dyspepsia

AIM：To evaluate the relationship between gallbladder （GB） motor function and H pylori infection in the stomach.
METHODS： All cases （86） underwent the 14C urea breath test （UBT）. ^14C-UBT was found as positive in 58 and negative in 28 dyspeptic patients. ^14C- UBT was accepted as a gold standard test. Clo test and histopathologic examination were compared with the results of ^14C-UBT in cases who tolerated upper gastrointestinal endoscopy procedure. Cholescintigraphy with ^99mTc-mebrofenin was used to determine the parameters of GB motor function （GB filling and emptying time, half of the emptying time, ejection fraction at 30th and 60th min） in all patients.
RESULTS： We found the sensitivity and specificity as 88% and 86% for Clo test and as 89% and 80% for histologic evaluation, respectively. The parameters of GB function were not significantly different in H pylori positive and negative patients. The GB emptying was normal in both groups. Minimum GB filling time was 30 min in 34 of 86 cases （39.5%）, filling was not observed in 2 cases. The GB ultrasonography （USG） results were normal for all cases and bile composition abnormality was not determined.
CONCLUSION： Our study showed that ^14C-UBT is highly reliable method to detect the presence of H pylori. The presence of H pylori infection does not directly affect the GB function.