Nocardial brain abscess in an immunocompetent host.

Nocardial infection of the central nervous system is rare and usually manifests as brain abscess. Here we describe an elderly gentleman who presented with signs and symptoms of an intracranial mass lesion localising to the frontal lobe. Clinical examination and CT scan suggested neoplasia as the probable diagnosis. A biloculated abscess was seen at surgery. Aspiration of the contents and examination of pus revealed Nocardia asteroides . Treatment included total excision and prolonged antibiotic therapy which resulted in an excellent outcome.

Investigation of an outbreak of device-related postoperative ventriculitis: a lesson learnt.

Pseudomonas aeruginosa (P aeruginosa) is one of the most common nosocomial pathogens. We report our experience of a device-related outbreak of postoperative ventriculitis caused by P aeruginosa thus initiating investigation of the unusual occurrence. Five neurosurgical patients were affected, postoperatively. The investigations entailed extensive screening of the common sources of contamination for colonization of P aeruginosa. Sterilized instruments used for surgery, including the ultrasonic aspirator (USA) sets and other hollow devices, were randomly sampled and cultured. Conventional culture methods yielded P aeruginosa, with almost similar antibiotic sensitivity pattern in all the patients and the ultrasonic aspirator, clinching the source of contamination. Routine surveillance, identification of unusual patterns, molecular epidemiological typing would be helpful in quick control of outbreaks of postoperative infections.

Comparative evaluation of BACTEC 460TB system and Lowenstein-Jensen medium for the isolation of M. tuberculosis from cerebrospinal fluid samples of tuberculous meningitis patients.

PURPOSE: To evaluate the role of the radiometric BACTEC 460TB system and the conventional Lowenstein-Jensen (LJ) medium for isolation of M. tuberculosis from cerebrospinal fluid (CSF) samples of tuberculous meningitis (TBM) patients. METHODS: CSF specimens (n=2325) from suspected TBM patients were processed for isolation of mycobacteria by inoculating BACTEC 12B medium and the LJ medium. The isolation of mycobacteria in both media was confirmed by microscopy and biochemical identification. Drug sensitivity testing for the anti-TB drugs was carried out by BACTEC radiometric method. RESULTS: Among the total 2325 CSF specimens processed by both methods, M. tuberculosis was isolated from 256 specimens. The isolation rates were 93% and 39% for the BACTEC system and LJ medium respectively. Both the media supported growth in 32% of the culture-positive specimens. BACTEC system alone yielded growth in 61% and LJ alone in 7%, of the culture-positive specimens. Among 205 isolates tested for drug susceptibility 81% were sensitive to all the drugs tested and 19% were resistant. CONCLUSIONS: The BACTEC 460TB system provides a highly sensitive and rapid tool for the isolation and drug susceptibility testing of M. tuberculosis, from CSF of TBM patients. Use of a solid medium in conjunction with the BACTEC 12B medium is essential for optimal recovery for M. tuberculosis from CSF specimens.

Central nervous system cladosporiosis: An account of ten culture-proven cases.

Background: Central nervous system (CNS) cladosporiosis is a rare infection caused by Cladophialophora bantiana. It has varied presentation and poor outcome. Most of the available data in the literature are reviews of individual case reports. Objective: To describe the clinical, radiological and mycological features of 10 cases of C. bantiana managed at a single tertiary center. To analyze the various treatment options, factors associated with outcome and to review the relevant literature. Materials and Methods: This is a retrospective study of 10 patients with CNS cladosporiosis managed at National Institute of Mental Health and Neurosciences from 1979 to 2006. It is a descriptive study. The case records were reviewed for clinical presentation, radiological features, management and outcome. Only those patients in whom the fungus could be isolated on culture were included in the study. Results: The age of the patients ranged from three to 42 years. Nine patients presented with features of space-occupying lesion and one patient with chronic meningitis. There were no specific clinical or radiological features. None of patients had impaired immune status. This infection presented as two pathomorphological forms - diffuse meningoencephalitis and focal abscesses. Burr hole tapping and excision are the surgical options. Both patients with burr hole tapping required excision of abscess subsequently. Two out of seven patients with abscess expired compared to all three patients with diffuse meningoencephalitis who expired. Recurrences occurred in four of the five patients following excision of the abscess. Combination antifungal treatment had better result than monotherapy. The outcome was poor with survival of only 50%. Conclusions: Thorough microbiological examination is required to diagnose CNS infection caused by C. bantiana. The outcome is better in patients with abscess. Excision of the abscess followed by combination antifungal therapy results in better outcome. Close follow-up is required due to high risk of recurrence.

Fatal Group A Streptococcal meningitis in an adult.

Despite the recent resurgence in reports of invasive Group A Streptococcal (GAS) infections worldwide, it remains a rare cause of pyogenic meningitis both in children and adults. We report a case of fatal GAS meningitis in a healthy adult emphasizing the need for clinicians to be aware of its fulminant course, prompting early diagnosis and treatment. There is also a need to consider postexposure chemoprophylaxis in close contacts of such cases.

Bacteriological profile of community acquired acute bacterial meningitis: a ten-year retrospective study in a tertiary neurocare centre in South India.

PURPOSE: Ten years retrospective study to evaluate the bacteriological spectrum of community acquired acute bacterial meningitis (CAABM). METHODS: Cerebrospinal fluid (CSF) samples from 385 clinically suspected cases of pyogenic meningitis were processed for cell counts, cytospin Gram stain, culture, antigen detection by latex agglutination (LAT) and antibiotic susceptibility test. Eighteen of these CSF samples were also subjected to a polymerase chain reaction (PCR) assay for detection of pneumococcal DNA. RESULTS: The etiological agent could be identified in 284 (73.8%) of the total 385 cases by culture and/or smear and /or LAT. Streptococcus pneumoniae was the predominant pathogen accounting for 238 (61.8%) cases. Haemophilus influenzae and Neisseria meningitidis accounted for 7 (1.8%) and 4 (1%) cases respectively. Other gram negative bacilli, Streptococcus spp. and Staphylococcus aureus were isolated from 19 (4.9%), 9 (2.3%) and 7 (1.8%) cases respectively. CONCLUSIONS: Streptococcus pneumoniae remains the major aetiological agent of CAABM both in adults and children in our set-up. No penicillin resistance was detected among the isolates. Further research should focus on preventable aspects of CAABM, especially pneumococcal vaccines, to help reduce the disease burden.

Antimicrobial resistance pattern among aerobic gram-negative bacilli of lower respiratory tract specimens of intensive care unit patients in a neurocentre.

BACKGROUND: Analysis of the tracheal and bronchial isolates from the lower respiratory tract specimens of the intensive care unit (ICU)-admitted patients, was carried out for the year 2002 with a perspective of looking at the antibiotic resistance pattern. METHODS: Lower respiratory tract secretions (tracheal or bronchoscopic aspirates) of 370 patients were cultured, identified and antimicrobial susceptibility performed by standard methods. RESULTS: Out of samples obtained from 370 patients, 274 (74%) were culture positive. A total of 489 bacterial isolates were recovered from 270 patients; 451 were gram-negative bacilli (GNB) and 38 were Staphylococcus aureus. In four of the patients, Candida spp was isolated. The common GNB isolates were non-fermentative gram-negative bacilli (NFGNB, 31.9%), followed by Pseudomonas aeruginosa (21.5%) and Klebsiella spp (19%). Elderly (24.8%) and adults (19.2%) showed increased rate of GNB isolation. In both tracheal and bronchial GNB isolates, the highest mean resistance was to cefazolin (98.8%) and ampicillin (97.6%) while the lowest mean resistance was to amikacin (48.5%). Isolation of two organisms per specimen (41.4%) was commonly seen. Multidrug resistance to the tested antimicrobials was more frequent in NFGNB (6.6%) and Pseudomonas aeruginosa (5%). There were no remarkable differences in the overall mean drug resistance among tracheal and bronchial GNB isolates. CONCLUSIONS: Isolation practices, antibiotic policies, effective surveillance, maintenance of epidemiological trends of infections and, rapid molecular diagnosis are the need of hour in improved and speedy management of lung infections with resistant organisms.

Neuropathology of HIV/AIDS with an overview of the Indian scene.

Neurological manifestations of HIV infection and AIDS are being recognized with a frequency that parallels the increasing number of AIDS cases. Next to sub-Saharan Africa, India has the second largest burden of HIV related pathology, essentially caused by HIV-1 clade C in both the geographic locales, in contrast to USA and Europe. But the true prevalence of HIV related neuroinfections and pathology is not available due to inadequate medical facilities, social stigma and ignorance that lead to underdiagnosis. Neurotuberculosis, followed by cryptococcosis and toxoplasmosis in various combinations are the major neuropathologies reflecting the endemicity and manifesting clinically by reactivation of latent infection. Discordance in the clinical prevalence of various infections, when compared to pathological studies highlight similarities in clinical, radiological modalities of diagnosis and inherent problems in establishing definitive diagnosis. Viral infections appear to be relatively rare. Inspite of heavy burden of HIV/AIDS, HIV associated neoplasia is infrequent, including primary CNS lymphomas. HIV encephalitis and HIV associated dementia are considered infrequent, though systematic studies have just been initiated in various centres. Peripheral neuropathy characteristically manifests with vasculitic neuropathy while diffuse infiltrative lymphocytosis syndrome (DILS) involving nerves has not been reported from India. Spinal cord pathology including vacuolar myelopathy is rare, even in asymptomatic cases. Till now the AIDS cases in India were drug naive but a new cohort of cases following initiation of HAART therapy as a national policy is soon emerging, altering the biology and evolution of HIV/AIDS in India. Lacunae in the epidemiology, diagnosis and study of biology of HIV/AIDS are outlined for future research.

Brain abscess due to cladophialophora bantiana.

Cladophialophora bantiana (Xylohypha bantiana) is a dematiaceous fungus with distinct neurotropism. CNS phaeohyphomycosis due to C. bantiana is an uncommon infectious condition and is associated with high mortality. We report this rare clinical entity in a 22-year-old male, presenting as brain abscess. Etiological diagnosis was made based on fungal culture and histopathological examination. Complete surgical resection of the lesion and treatment with antifungal agents could not save the patient from this frequently fatal infection.

Cryptococcosis in the immunocompromised host with special reference to AIDS.

Cryptococcosis is increasing because of an ever rising population of immunocompromised individuals especially those with acquired immune deficiency syndrome (AIDS). Cryptococcal infection of the central nervous system (CNS) were diagnosed in 149 cases over a period of 19.5 years (January 1978-June 1998). Culture was positive in all cases except three who were already on antifungal therapy. India ink mounts of cerebrospinal fluid (CSF) revealed encapsulated cryptococci in 134, and cryptococcal antigen was detected in 111 of 114 patients tested. A comparison of laboratory and certain clinical parameters in patients with and without associated HIV infection showed that a poor CSF cell response and culture of cryptococci from extra-neural sites was more often associated with HIV infection and was statistically significant. Further, presence of concomitant infection especially tuberculosis, and mortality were higher in the HIV positive group.

Profile of neurologic disorders associated with HIV/AIDS from Bangalore, south India (1989-96).

One hundred patients (95 males, 5 females, mean age at presentation 31.6 +/- 9.4 yr) with various neurological disorders associated with HIV infection during 1989-1996 were evaluated at NIMHANS, Bangalore. Eighty patients belonged to group I associated with opportunistic neuroinfections and 20 to group II--non infectious neurological disorders. Cryptococcal meningitis either alone (n = 31) or associated with tuberculous meningitis (n = 6) was the most common (46.3%) followed by neurotuberculosis either alone (n = 24) or with cerebral toxoplasmosis (n = 4) accounting for 35 per cent. Other opportunistic neuroinfections included cerebral toxoplasmosis, herpes zoster, fulminant pyogenic meningitis and neurosyphilis. Clinical characteristics, diagnostic clues, their laboratory and radiological profiles and problems encountered in diagnosis and management of these opportunistic infections are highlighted. In group II (19 males and one female; mean age of 32.6 +/- 9.4 yr), two patients had cortical dementia, three acute brain stem involvement, two epilepsy and one had features suggestive of progressive multifocal leukoencephalopathy. Two patients of group I during follow up developed cortical dementia. Six had peripheral nervous system involvement similar to Guillain-Barre syndrome. Sixty six patients (63 of group I and 3 of group II) progressed to AIDS, 33 patients from group I and one patient from group II succumbed to the disease. With the rapid increase in the incidence of HIV/AIDS and an increase in the neurological manifestations of HIV/AIDS it is important to recognise the magnitude of the problem for health planning in India.

Immunohistochemical study of the expression of human groEL-stress protein in human nervous tissue.

Monoclonal antibody (ML-30) directed against 65 kDa stress protein of mycobacteria, is shown to identify human cellular protein homologous with the groEL heat shock protein in many prokaryotes. Immunohistochemical survey of nervous tissue, both central and peripheral, from patients dying of various inflammatory, degenerative and neoplastic conditions and from experimental animals, using this antibody showed punctate granular staining of the cells to a variable degree. The astrocytes showed strong immunolabelling. The normal neurons and oligodendroglia stained variably, while abnormal neurons were darkly labelled. Ependymal cells showed apical granular positivity. The ubiquitinated inclusion bodies in amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease were not recognised by the ML-30 antibody. In diseased and stressed nervous tissue from experimental animals, the expression of the ML-30 recognisable stress protein was variable. The epitope recognised by ML-30 was found stable in postmortem tissues collected up to 36 h after death and processed for paraffin sectioning, after fixation in formalin for many years. Enhanced expression of the human groEL stress protein homologue in mammalian nervous tissue following various forms of stress may play a role in modulating the extent of tissue damage by autoimmune mechanism because of its high immunogenic nature and constitutive presence in the cells.

Assessment of suitability & ease of performance of seven commercial assay systems for the detection of antibodies to HIV-1.

In this study, we have evaluated the suitability and ease of performance of seven HIV assays namely: Vironostika anti-HIV Uni-Form; Vironostika HIV MIXT; Elavia MIXT; Genelavia MIXT; Serodia-HIV; Immunocomb Bi-spot; and Test pack HIV-1 and 2 Abbott, for use in Indian laboratories. A panel of 41 blind coded Western blot confirmed sera were used for this purpose. Rapid assays like Immunocomb Bi-Spot, Serodia HIV and Test pack HIV-1/HIV-2 Abbott were found to be more suitable and easy to perform as compared to the ELISAs. Sensitivity of all the assays was excellent (100%). Specificity of Serodia HIV, Immunocomb Bi-spot, Test pack HIV-1 and 2 Abbott and Elavia MIXT were excellent (100%), while that of Vironostika MIXT and Vironostika anti-HIV Uni-Form was poor. Positive predictive value of the assays ranged from 64.5 to 100 per cent. Negative predictive value of six of the assays was 100 per cent and that of Vironostika anti-HIV Uni-Form was very poor.

Pathological lesions in HIV positive patients.

Pathomorphological features of 10 HIV positive individuals studied at autopsy and biopsy are described. Nine patients had evidence of neuro-AIDS and eight of them succumbed to various opportunistic infections. One surviving patient underwent a diagnostic lymph node biopsy which revealed tuberculous lymphadenopathy. Cryptococcal meningitis was the commonest CNS opportunistic infection, seen in five cases, with disseminated systemic cryptococcosis in two. The other opportunistic infections included toxoplasma encephalitis in two, with acanthamoeba infection in one patient. Pulmonary tuberculosis was noted in three patients while other bacterial infections such as meningococcal meningitis, pseudomonas septicaemia were observed in three and pneumocystis carinii pneumonia in one. One seropositive individual was clinically asymptomatic but succumbed to a road traffic accident. The brain in this case showed features of HIV associated early leucoencephalopathy. Bacterial infections caused by organisms other than Mycobacterium tuberculosis associated with AIDS are often underdiagnosed and should be considered, especially in developing countries. In cases of cryptococcal and tuberculous meningitis or multiple parasitic infections, the patients should be screened for associated HIV infection.

The role of immunological & virological techniques in the diagnosis of herpes simplex encephalitis.

The efficacy of immunological and virological methods in the diagnosis of herpes simplex encephalitis (HSE) was studied in 22 patients diagnosed as HSE by clinical, radiological EEG parameters. CSF cell counts were elevated in 14 of 18 patients with a lymphocytic predominance in 13. Virus specific IgG antibody detection by ELISA in paired CSF samples was possible in 8 of 17 patients. HSV antigen could be detected by immunohistochemical methods in the cells of the CSF and/or brain tissue in 7 of 9 patients. In four of them antemortem diagnosis was possible facilitating prompt specific antiviral therapy. Virus isolation was possible in 2 of 8 patients, one from brain biopsy tissue and the other from brain tissue obtained at autopsy. Using all the three methods, the diagnosis of HSE could be confirmed in 14 of 22 (63.6%) patients.

Sub acute and chronic meningitis in children--an immunological study of cerebrospinal fluid.

Cerebrospinal fluid (CSF) from 274 cases of subacute to chronic meningitis in age groups from 3 months to 12 years were analysed for the presence of antibody response to mycobacterial and cysticercal antigens by enzyme linked immunosorbent assay (ELISA). Simultaneously other correlative parameters such as CSF cell cytology by cytospin studies, mycobacterial antigens of Lipoarabinomannan (LAM) type (a polysaccharide antigen) by reverse passive haemagglutination assay (RPHA) CSF C-reactive protein (CRP) by latex agglutination and microbial cultures for mycobacterium tuberculosis and fungi were carried out. Antimycobacterial antibody was present in 35.4% of the cases. In 57.66% of the cases there was no demonstrable immune response to either mycobacterial or cysticercal antigens. However, it was interesting to note that 5.47% of the cases revealed the presence of anticysticercal antibody in the CSF. The mycobacterial antigen (LAM polysaccharide antigen) was found in 72.6% of the cases. There was no evidence of carcinomatous or cryptococcal meningitis. This study stresses the role of multimodal diagnostic tests on CSF for investigating cases of chronic and subacute meningitis irrespective of leading clues such as tuberculosis.

Antigenic analysis of Cysticercus cellulosae by crossed immunoelectrophoresis & its role in immune diagnosis of neurocysticercosis.

The antigenic composition of Cysticercus cellulosae cysts excised from infected pig and autopsied human brain was analysed by crossed immunoelectrophoresis with an intermediate gel technique using rabbit hyperimmune serum. Normal pork muscle and human brain antigen were used to differentiate parasite derived components from that of host. Attempts were made to look for the rich source of parasitic immunodominant antigens by analysing preparations of different parts of cyst namely scolex and fluid using rabbit hyperimmune serum. Twenty three antigenic components were identified in sonicate extract of porcine cyst, of which 15 were parasite derived. On comparison with antigens of whole cyst sonicate, scolex showed 10, cyst fluid 9 and human cyst sonicate 11 parasite derived antigens. Serum and cerebrospinal fluid (CSF) of neurocysticercotic patients reacted with 12 parasite derived antigens of porcine cyst sonicate (PCS) in a heterogenous manner. It was also noticed that human cyst sonicate (HCS) lacked 4 of the parasite derived antigens present in the PCS.