First outbreak of multidrug-resistant Klebsiella pneumoniae producing both SHV-12-type extended-spectrum beta-lactamase and DHA-1-type AmpC beta-lactamase at a Korean hospital

PURPOSE: Coexistence of different classes of beta-lactamases in a single bacterial isolate may pose diagnostic and therapeutic challenges. We investigated a spread of Klebsiella pneumoniae isolates co-producing an AmpC beta-lactamase and an extended-spectrum beta-lactamase (ESBL) in a university hospital. MATERIALS AND METHODS: Over a three-month period, a total of 11 K. pneumoniae isolates, which exhibited resistance to cefotaxime, aztreonam, and cefoxitin, were isolated. These isolates showed positive to ESBLs by double disk tests. Minimal inhibitory concentrations (MICs) were determined by broth microdilution testing. All isolates were examined by isoelectric focusing, PCR and sequence analysis to identify bla(SHV) and bla(DHA), and molecular typing by pulsed-field gel electrophoresis (PFGE). RESULTS: All 11 isolates were highly resistant (MIC, > or = 128microg/ml) to ceftazidime, aztreonam, and cefoxitin, while they were susceptible (MIC, < or = 2microg/ml) to imipenem. The bla(SHV-12) and bla(DHA-1) genes were detected by PCR and sequence analysis. PFGE revealed a similar pattern in 10 of the 11 strains tested. CONCLUSION: This is the first outbreak report of K. pneumoniae in Korea which co-produced SHV-12 and DHA-1 beta-lactamase, and we suggest a clonal spread of multidrug-resistant K. pneumoniae at a hospital.     

Performance evaluation of three automated quantitative immunoassays and their correlation with a surrogate virus neutralization test in coronavirus disease 19 patients and pre‐pandemic controls

BackgroundSARS‐CoV‐2 pandemic is currently ongoing, meanwhile vaccinations are rapidly underway in some countries. The quantitative immunoassays detecting antibodies against spike antigen of SARS‐CoV‐2 have been developed based on the findings that they have a better correlation with the neutralizing antibody.MethodsThe performances of the Abbott Architect SARS‐CoV‐2 IgG II Quant, DiaSorin LIAISON SARS‐CoV‐2 TrimericS IgG, and Roche Elecsys anti‐SARS‐CoV‐2 S were evaluated on 173 sera from 126 SARS‐CoV‐2 patients and 151 pre‐pandemic sera. Their correlations with GenScript cPass SARS‐CoV‐2 Neutralization Antibody Detection Kit were also analyzed on 173 sera from 126 SARS‐CoV‐2 patients.ResultsArchitect SARS‐CoV‐2 IgG II Quant and Elecsys anti‐SARS‐CoV‐2 S showed the highest overall sensitivity (96.0%), followed by LIAISON SARS‐CoV‐2 TrimericS IgG (93.6%). The specificities of Elecsys anti‐SARS‐CoV‐2 S and LIAISON SARS‐CoV‐2 TrimericS IgG were 100.0%, followed by Architect SARS‐CoV‐2 IgG II Quant (99.3%). Regarding the correlation with cPass neutralization antibody assay, LIAISON SARS‐CoV‐2 TrimericS IgG showed the best correlation (Spearman rho = 0.88), followed by Architect SARS‐CoV‐2 IgG II Quant and Elecsys anti‐SARS‐CoV‐2 S (all rho = 0.87).ConclusionsThe three automated quantitative immunoassays showed good diagnostic performance and strong correlations with neutralization antibodies. These assays will be useful in diagnostic assistance, evaluating the response to vaccination, and the assessment of herd immunity in the future.     

Utility of combined (18)F-fluorodeoxyglucose-positron emission tomography and computed tomography in patients with cervical metastases from unknown primary tumors

(18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) has been reported to identify primary tumors in patients with cervical metastases from cancer of unknown primary (CUP). However, few reports have assessed the use of combined FDG-PET/computed tomography (CT) in this setting. We therefore examined the utility of combined FDG-PET/CT in the detection of primary tumors and unrecognized metastases in these patients. Patients with previously untreated CUPs underwent head and neck CT and whole-body FDG-PET/CT before panendoscopy and guided biopsy. The diagnostic accuracy of CT and FDG-PET/CT in detecting primary tumors and cervical metastases was compared with that of histopathology. The ability of FDG-PET/CT to detect distant metastases was also tested. Of the 44 eligible patients, 16 had occult primary tumors in the head and neck. FDG-PET/CT was significantly more sensitive than CT for detecting primary tumors (87.5% vs. 43.7%, P=.016), but their specificity did not differ (82.1% vs. 89.3%, P=.500). Thirty-four of 44 patients underwent neck dissection; 67 of 182 dissected cervical levels had metastatic nodal diseases. On a level-by-level basis, FDG-PET/CT was significantly more sensitive than CT (94.0% vs. 71.6%, P<.001), but the two methods were equally specific (94.8% vs. 96.5%). FDG-PET/CT correctly detected distant metastases in 6 of 6 patients. Combined FDG-PET/CT is a useful screening method for primary tumor detection, accurate nodal staging, and distant metastases in patients with CUPs.     

One-year results of intravitreal ranibizumab for neovascular age-related macular degeneration and clinical responses of various subgroups

Purpose  

To report 1-year clinical outcomes of intravitreal ranibizumab treatment for choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) and to identify predictive factors that may influence visual acuity (VA) outcomes in Korean patients.     

Morphometric study of regeneration through vascularized nerve graft in a rabbit sciatic nerve model

Adequate vascularization is essential for a successful nerve graft. Theoretically, immediate vascularization will minimize fibroblast infiltration and support axonal regeneration. In this study, histomorphologic and morphometric studies were carried out to determine whether vascularized grafts are beneficial, in terms of axonal regeneration. In a rabbit model, 4-cm segments of sciatic nerve were obtained and placed as a nonvascularized graft on one side, and as a pedicled vascularized graft fed by the inferior gluteal vessel on the contralateral side. Histomorphologically, the distribution of myelinated nerve fibers and Schwann cells was evaluated after toluidine blue staining, at 2-, 3-, and 4-month intervals. The following results were obtained. 1) Myelinated nerve fibers were more abundant in the proximal, middle, and distal segments of the vascularized nerve group at 2 and 3 months. 2) The average nerve-fiber diameter was greater in the vascularized nerve graft group at 2, 3, and 4 months (2 to 10 microm). 3) Schwann cells were more abundant in the proximal, middle, and distal segments of the vascularized nerve graft group at all time points. Based on the above findings, the immediate restoration of circulation in the vascularized nerve graft can be accountable for the increased number of surviving Schwann cells, the rapid clearing of axons, and myelin-sheath changes that occur during Wallerian degeneration, thus enabling "morphologically" optimal regeneration.     

Inhibition of histamine turnover by 8-OH-DPAT,buspirone and 5-hydroxytryptophan in the mouse and rat brain

Summary The effects of 5-hydroxytryptamine (5-HT) receptor agonists on histamine turnover in mouse and rat brains were examined. The histamine turnover rate was estimated from the accumulation of tele-methylhistamine 90 min after i.p. injection of pargyline (65 mg/kg). In whole mouse brains, the histamine turnover was significantly inhibited by the 5-HT_1A agonists, 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT) (> 0.5 mg/kg) and buspirone (> 2 mg/kg) injected s. c. 10 min before pargyline treatment. 5-hydroxytryptophan (20 mg/kg) also significantly inhibited histamine turnover. Injections of the 5-HT_1B agonist m-trifluoromethylphenylpiperazine (10 and 20 mg/kg) or the 5-HT₂ agonist (1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (1, 2 and 5 mg/kg)), however, did not affect histamine turnover. The inhibitory effect of 8-OH-DPAT (1 mg/kg) on histamine turnover was significantly antagonized (by 40%) by pindolol (20 mg/kg) and slightly antagonized (by 29%) by spiperone (10 mg/kg), while methysergide (20 mg/kg) and ketanserin (10 mg/kg) demonstrated no antagonistic effects. 8-OH-DPAT (0.3 and 1 mg/kg) also showed an inhibiting effect on histamine turnover in various regions of rat brains. Although the extent of inhibition was slightly larger in the striatum and cerebral cortex, there was no marked regional difference. These results suggest that histaminergic activity in the brain is regulated by 5-HT_1A receptors. Send offprint requests to R. Oishi at the above address