Bacterial isolation with on-site inoculation of ascites fluid into hemoculture bottle in spontaneous bacterial peritonitis.

OBJECTIVE: To compare the on-site bacterial inoculation of ascites fluid into hemoculture bottle with routine method in the patients who were preliminary diagnosed of SBP. MATERIAL AND METHOD: A retrospective analysis of case records during January-December 2001. RESULTS: A total of 673 specimens from 325 patients were retrieved from the data records at the Department of Microbiology, Siriraj Hospital in 2001. The neutrocytic ascites were found in 163 specimens (94 patients). The routine method and on-site inoculation into the hemoculture bottle were employed in 107 and 56 specimens respectively. Culture-positive neutrocytic ascites was found in the routine method 16 (14.9%) specimens and in the on-site inoculation 26 (46.4%) specimens (p < 0.0001). Among these samples, the two methods were simultaneously performed in 42 specimens of which 18 paired specimens were eligible for analysis. Positive culture was found in 2 samples in which the routine method and in an additional 5 samples in which on-site inoculation into hemoculture bottle method. Using Kappa analysis (e score = 0.328, 95% CI = -0.172 to 0.829) that can be interpreted the on-site inoculation method had a higher yield than the routine technique. Moreover, 21 cases also had their blood and ascites samples simultaneously collected and cultured. 4 of ten (19%) and 5 of eleven (23.8%) cases were found in the routine and on-site and direct inoculation groups respectively. These finding suggested that the severity of infection in among two groups were similar and unlikely to be the cause of the difference of the positive isolation rate in both groups. CONCLUSION: The on-site and direct inoculation of ascites into hemoculture bottle method had a significantly higher isolation rate than routine method (i.e. 46.4% versus 14.9% p < 0.0001) either with separated or paired samples of ascites.

Neurocysticercosis : Clinical manifestations and assessments.

Objective : In patients who have symptoms of epilepsy and other neurological deficits, one of the most common parasitic infections is neurocysticercosis (NCC) caused by Cysticercus cellulosae, the larval form of Taenia solium. In order to evaluate the characteristics of this illness which define the diagnosis, we assessed clinical manifestations, a positive ELISA for cysticercosis and neurological imaging in patients suspected of having NCC at a teaching hospital. Methods : This retrospective cohort study assessed 44 patients, who had laboratory results and clinical manifestations compatible with a diagnosis of NCC, between November 1998 and November 2001. The criteria for diagnosing this illness modified from these of Del Brutto and colleagues\\\' criteria. All patients were investigated with serum ELISA, 18 with CSF ELISA, if there was no contraindication. T. solium vesicular cyst soluble antigen was used for the detection of cysticercosis (T. solium) antibodies by solid-phase enzyme immunoassay. 35 patients were further investigated by a computerized tomography (CT) scan of central nervous system (CNS), if the results of other investigations were inconclusive. Using these criteria, we stratified all patients into three groups: possible NCC (19), probable NCC (10), and definite NCC (15). All definite patients were further examined with ELISA for Angiostrongylus cantonensis and Western blot for Gnathostoma spinigerum in order to look for cross-reactivity of the ELISA for cysticercosis. Results : In this study, a prevalence of NCC (34.1%) in the group of patients in whom there was clinical suspicion of NCC makes us concerned that Thailand is still an endemic area for this disease. The three most common clinical presentations were seizures, neurological deficit, and signs of increased intracranial pressure. Serum ELISA showed a sensitivity of 33.3% and a specificity of 93.1%. CSF ELISA showed a sensitivity of 40.0% and a specificity of 100%. CT scan brain showed a high sensitivity (92.9%) with a modest specificity (52.4%). Cross-reaction with other parasitic proteins was found with A. cantonensis (6.7%), but not with G. spinigerum. Conclusion : NCC is still endemic in Thailand. In the approach to this illness, we conclud that the diagnosis of NCC should be based on the patient's history and physical signs in conbination with radiological and serological investigations. Moreover, in areas where A. cantonensis and G. spinigerum were also prevalent, case should be taken in the interpretation of a positive ELISA for cystercercosis because of cross-reactivity with antibodies to A. cantonensis which should be checked individually.

Cerebral toxoplasmosis in AIDS patients: Clinical manifestations and laboratory diagnosis.

Objective : Patients with acquired immunodeficiency syndrome (AIDS) are susceptible to a variety of infections. Cerebral toxoplasmosis is one of the most common. The presumptive diagnosis is based on clinical manifestations, a positive Toxoplasma antibody test, characteristic neuroradiological abnormalities, and improvement after specific therapy. We evaluated not only the clinical manifestations and laboratory diagnosis but also its prevalence and the CD4 count in relationship to the development of cerebral toxoplasmosis in order to determine its place in the natural history of HIV infection. Methods : A retrospective cohort study was performed in 104 AIDS patients who were stratified into three levels: 35 with a definite diagnosis of cerebral toxoplasmosis and 41 with a probable diagnosis and 104 with a possible diagnosis. The criterion for diagnosing definite illness was a good response to specific treatment. Toxoplasma IgM were detected using solid-phase enzyme immunoassay and monoclonal captured ELISA methods respectively in all patients. 65 cases without a definitive diagnosis were further investigated with a CT scan of the brain. The patient data were followed up on day 7 and 14. Result : Toxoplasma IgG was present in 37 out of all case (35.6%) and Toxoplasma IgM was positive in only one case. The study showed that ELISA was a valuable method for diagnosis in addition of a CT scan of the brain. The ELISA detected antibodies in 24 out of 35 cases with a definite diagnosis (sensitivity 68.6%, 95% CI 5.7%-83.2%) and no antibody in 56 out of 69 cases with other diagnoses (specificty 81.2%, 95% CI 69.9%-89.6%). The CT scan showed positive features in 30 out of 33 cases with definite diagnosis (sensitivity 90.9%, 95% CI 75.7%-98.1%) but there were 4 (out of 32 cases) with a positive CT scan who were negative for the diagnosis, i.e., false positive, giving a specificity of 87.5%, 95% CI 71.0%-96.5%. The most common clinical presentations were headache and neurological deficit. Interestingly, neurological deficit was the only clinical manifestation that was associated with cerebral toxoplasmosis, when the group with a definite diagnosis was compared with the other diagnosis group (p-value 0.006). In HIV seropositive patients with previous Toxoplasma infection, cerebral toxoplasmosis was present in 24 out of 37 cases who were positive for Toxoplasma IgG (positive predictive value 64.9%), particularly in individuals with a CD4 count less than 100 cells/mm1. Conclusion : The two most common clinical manifestations were headache and neurological deficit. Detection of Toxoplasma gondii IgG and CT scan of the brain are valuable tools for the diagnosis of cerebral toxoplasmosis. Cerebral toxoplasmosis is mainly caused by reactivation, as Toxoplasma IgM antibodies were found in only one case.