The World Goes \u27Round (October 8-10, 15-17, 1998)

Program for The World Goes \u27Round (October 8-10, 15-17, 1998)

A Highly Virulent Staphylococcus aureus: Rabbit Anterior Chamber Infection, Characterization, and Genetic Analysis

PURPOSE. To describe and characterize a Staphylococcus aureus strain with unique virulence that overcomes host defenses of the rabbit anterior chamber and mimics clinical cases of postcataract surgery endophthalmitis. METHODS. Nine isolates of S. aureus were tested to determine their viability in the rabbit anterior chamber. Growth of UMCR1 in the anterior chamber was established and expressed as log colony-forming units per milliliter of aqueous humor. Pathologic changes produced by UMCR1 were documented by photographs, slit lamp examination, histopathologic analysis, and quantification of neutrophils. UMCR1 was characterized by antibiotic susceptibility, biochemical tests, ribotyping, genome restriction mapping, and multilocus sequence typing (MLST). RESULTS. UMCR1 was the only S. aureus strain that grew within the anterior chamber, reaching log 6.97 Ϯ 0.18 CFU/mL by 16 hours after infection. Pathologic changes included conjunctival injection, chemosis, corneal edema, severe iritis, fibrin accumulation, and a 193-fold increase in neutrophils by 16 hours after infection. UMCR1 was only resistant to sulfamethoxazole and, like other S. aureus isolates, polymyxin B. UMCR1 also had biochemical reactions and a ribotype pattern typical of S. aureus. The genomic reconstruction analysis of UMCR1 was most similar to strains MW2 and MSSA476. MLST revealed a 1 in 3198 nucleotide difference between UMCR1 and strains MW2 and MSSA476. CONCLUSIONS. This study describes a unique S. aureus strain that overcomes host defenses and replicates in the anterior chamber. The survival and growth of this organism could be used for studies of S. aureus pathogenesis, host defenses, and effectiveness of antibiotics within the anterior chamber. (Invest Ophthalmol Vis Sci. 2010;51:5114 -5120

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No sponsorships or competing interests have been disclosed for this article. Objective. To determine oncological and neuromorbidity out-comes in patients with advanced head and neck cancer (stage IVB) requiring sacrifice and reconstruction of the car-otid artery. Study Design. Case series with chart review. Setting. Tertiary care referral center. Subjects and Methods. Overall, 51 patients underwent carotid artery sacrifice during surgical treatment of the neck, in both the primary and salvage setting. All patients underwent auto-genous in-line carotid artery bypass grafting with either saphenous vein or the deep femoral vein in conjunction with vascular surgery. In all, the study included 39 males and 12 female subjects, with age ranging from 39 to 82 (mean, 62.7). Results. Two patients (3.9%) had a cerebral vascular accident in the immediate postoperative period. The remaining 49 patients (96%) had no neurologic sequela. Serial ultrasonic evaluation revealed 4 patients with intra-luminal thrombus within the site of reconstruction. Perioperative mortality occurred in a single patient. Disease-related mortality occurred in 9.8 % (5) of patients, with an overall 2-year sur-vival of 82%. Conclusions. We presently report the largest series of surgi-cal treatment for advanced head and neck cancer with caro-tid artery involvement. We document an overall 2-year survival of 82 % in the setting of low perioperative neuro-morbidity and mortality rates. We therefore consider caro-tid artery sacrifice and autogenous vein graft reconstruction in the absence of distant metastatic disease as a viable treat-ment option for what was once thought to be a palliative procedure. Keywords carotid artery sacrifice, radical neck dissection, head an

Plasticity of the injured human spinal cord: insights revealed by spinal cord functional MRI.

IntroductionWhile numerous studies have documented evidence for plasticity of the human brain there is little evidence that the human spinal cord can change after injury. Here, we employ a novel spinal fMRI design where we stimulate normal and abnormal sensory dermatomes in persons with traumatic spinal cord injury and perform a connectivity analysis to understand how spinal networks process information.MethodsSpinal fMRI data was collected at 3 Tesla at two institutions from 38 individuals using the standard SEEP functional MR imaging techniques. Thermal stimulation was applied to four dermatomes in an interleaved timing pattern during each fMRI acquisition. SCI patients were stimulated in dermatomes both above (normal sensation) and below the level of their injury. Sub-group analysis was performed on healthy controls (n = 20), complete SCI (n = 3), incomplete SCI (n = 9) and SCI patients who recovered full function (n = 6).ResultsPatients with chronic incomplete SCI, when stimulated in a dermatome of normal sensation, showed an increased number of active voxels relative to controls (p = 0.025). There was an inverse relationship between the degree of sensory impairment and the number of active voxels in the region of the spinal cord corresponding to that dermatome of abnormal sensation (R(2) = 0.93, pConclusionsIn this work we demonstrate the use of spinal fMRI to investigate changes in spinal processing of somatosensory information in the human spinal cord. We provide evidence for plasticity of the human spinal cord after traumatic injury based on an increase in the average number of active voxels in dermatomes of normal sensation in chronic SCI patients and an increased number of intraspinal connections in incomplete SCI patients relative to healthy controls

Metallo-β-Lactamase Production by Pseudomonas otitidis: a Species-Related Trait ▿

Susceptibility to several β-lactams and β-lactamase production was investigated in a collection of 20 strains of Pseudomonas otitidis, a new Pseudomonas species that has been recently recognized in association with otic infections in humans. All strains appeared to be susceptible to piperacillin, cefotaxime, ceftazidime, and aztreonam, while resistance or decreased susceptibility to carbapenems was occasionally observed. All strains were found to express metallo-β-lactamase (MBL) activity and to carry a new subclass B3 MBL gene, named blaPOM, that appeared to be highly conserved in this species. P. otitidis, therefore, is the first example of a pathogenic Pseudomonas species endowed with a resident MBL. The POM-1 protein from P. otitidis type strain MCC10330 exhibits the closest similarity (60 to 64%) to the L1 MBL of Stenotrophomonas maltophilia. Expression in Escherichia coli and Pseudomonas aeruginosa revealed that, similar to L1 and other subclass B3 MBLs, POM-1 confers decreased susceptibility or resistance to carbapenems, penicillins, and cephalosporins but not to aztreonam. Expression of the POM MBL in P. otitidis is apparently constitutive and, in most strains, does not confer a carbapenem-resistant phenotype. However, a strong inoculum size effect was observed for carbapenem MICs, and carbapenem-resistant mutants could be readily selected upon exposure to imipenem, suggesting that carbapenem-based regimens should be considered with caution for P. otitidis infections