Role of Biofilm in Cerebrospinal Fluid Shunt Infections: A Study at Tertiary Neurocare Center from South India

INTRODUCTION

Biofilms are the source of persistent infections of many pathogenic microbes. They are responsible for nosocomial infection and also associated with many surgical conditions including indwelling medical devices such as ventriculoperitoneal shunt. A significant problem encountered in shunt procedures is obstruction followed by infection, with infection rate ranging from 2% to 27%, often with poor outcome.

MATERIALS AND METHODS

This study was conducted in the Department of Neuromicrobiology at a tertiary neuroinstitute for 6 months from July 1 to December 31, 2014. The samples comprised cerebrospinal fluid (CSF) from suspected cases of shunt infections. Laboratory diagnosis of causative agent was established by adopting standard procedures. Then, isolates were evaluated for production of biofilm by tissue culture plate (TCP) method and tube method.

RESULTS

Of the 1642 shunt CSF samples obtained from neurosurgery, 14.79% were culture positive which yielded 254 isolates. About 51.97% were Gram-negative bacilli (GNB), 46.46% were Gram-positive cocci (GPC), and 1.57% were Candida albicans. Among GNB, nonfermenters were the most common (51.52%) followed by Pseudomonas aeruginosa (15.9%). Among GPC, coagulase-negative Staphylococci were 88.13%, out of which 43.26% were methicillin-resistant. Other GPC were Enterococcus spp. (4.24%), Staphylococcus aureus (5.08%), and Streptococcus spp. (2.54%). Among all isolates, 120 were tested for biofilm production, out of which 57.5% were biofilm producers and 42.5% were nonproducers.

CONCLUSIONS

TCP was the better method to detect biofilm. Most of the biofilm producers were resistant pathogens.

Hospital-acquired pneumonia due to Leclercia adecarboxylata in a neurosurgical centre

Leclercia adecarboxylata, a gram-negative bacillus of the Enterobacteriaceae family, is an uncommonly identified human pathogen. The organism has been reported worldwide and isolated from various environmental sources. Most human infections are polymicrobial and commonly occur in immunocompromised hosts, although nosocomial infections in immunocompetent hosts have been documented. We describe three case reports of L. adecarboxylata isolation from cases of hospital acquired pneumonia admitted to a tertiary care center for neurosurgical care.

A simple method for evaluating stereotactic accuracy of Magnetic Resonance Imaging and Computed Tomography Imaging in Frame Based Radiosurgery

PURPOSE

To design a simple and reproducible method with minimum uncertainty for evaluating the stereotactic accuracy of Computed Tomography imaging and Magnetic Reso-nance Imaging and to compare the results.

METHODS

3D phantom has been designed with 1 mm diameter targets in eight sectors for stereotactic MR imaging and CT imaging. The phantom was connected to Leksell stereotactic frame and the images obtained are exported to treatment planning system. Leksell stereotactic coordinates (X, Y, Z) of the holes are determined in each slice and mean maximum errors were calculated along with 3D vector distances from center of stereotactic coordinate system (100,100,100) to five known Targets. The target volumes are calculated independently for each image data sets.

RESULTS

The mean of maximum absolute error estimated for MR images from the Siemens Magnetom vision MR unit were 0.46 mm (X-Axis), 1.66 mm (Y-Axis) and 2.11 mm (Z-Axis). Mean of absolute maximum error estimated using CT images from the Philips Brilliance 16 CT scanner were 0.29mm (X-axis), 0.51mm (Y-Axis) and 0.90mm (Z-Axis). 3D vector calculations were 0.38 mm for CT and 0.72 mm for MRI. No significant variation is noticed in volume calculations from both image data sets.

CONCLUSION

This study showed that accuracy and quality of stereotactic CT- imaging and MR-imaging are limited by localization devices and their designs in frame based Radiosurgery. This method is simple, direct and economical with good resolution and high reproducibility.

KEYWORDS

Stereotactic accuracy, Computed Tomography, Magnetic Resonance Imaging, frame based Radiosurgery.

Medulloblastoma with extensive nodularity: a variant occurring in the very young-clinicopathological and immunohistochemical study of four cases

CASE REPORT

Four cases of medulloblastoma with extensive nodularity (MBEN) are described. The patients were 3 years of age or younger at diagnosis. Cranial CT scan disclosed multiple coalescing nodules with peculiar 'grape-like' architecture in three patients. A near total excision of the tumour was performed in all four patients. The patients are currently receiving radiation and chemotherapy. Histologically, the tumours were characterized by extreme nodularity with intranodular uniformity and low proliferative index. The internodular zones were extremely cellular, composed of undifferentiated, mitotically active cells. Bcl-2 protein expression was observed in the cellular zones but was distinctly absent within nodules.

DISCUSSION

MBEN represents a variant that occurs in very young children but has a good prognosis. The favourable outcome is probably related to its spontaneous neurocytic differentiation. The pattern of Bcl-2 immunoreactivity in MBENs indicates that this protein could be a key player in the regulation of neuronal differentiation in medulloblastomas.

Neurogenic heterotopic ossification : a diagnostic and therapeutic challenge in neurorehabilitation

Heterotopic ossification (HO) is an important cause of restriction in range of movements and secondary motor disability following neurotrauma, orthopaedic interventions and burns. It has not received focussed attention in non-traumatic neurological disorders. In a prospective study of 377 patients, on medical problems in neurological rehabilitation setting, 15 subjects (3.97%) had neurogenic heterotopic ossification. Their clinical diagnosis was: transverse myelitis (7), neurotuberculosis (4), traumatic myelopathy (2) and stroke (2). Hip (10), knee (4) and elbow joints (1) were involved. The risk factors included urinary tract infection (15), spasticity (6), pressure sores (13) and deep venous thrombosis (DVT) (6). The initial diagnosis was often other than HO and included DVT (3), haematoma (2) and arthritis (2). ESR and serum alkaline phosphatase levels were elevated in all but one subject. The diagnosis of HO was established using X-rays, CT Scan and three-phase bone scan. Following treatment with non-steroidal anti-inflammatory drugs, the range of motion improved in only four patients. HO resulted in significant loss of therapy time during rehabilitation. High index of suspicion about this complication is necessary for early diagnosis and prompt intervention.