A Nagendra

Incidence and Drug Susceptibility pattern of Mycobacterium tuberculosis in HIV infected Patien

Incidence of HIV infection in patients with tuberculosis was found out by serological method (ELISA) with confirmation by Western Blot analysis. Out of 2116 tuberculosis patients tested for HIV, 150 cases were found to be positive for HIV infection (5.73%). Drug susceptibility to first line antitubercular drugs was carried out in 1378 isolates from HIV negative cases and 68 isolates from AIDS cases. The overall resistance pattern to one or more drugs was seen in 13.78% of isolates from HIV negative cases as compared to 7.2% isolates in AIDS cases. Multidrug resistance (MDR) was seen in 8.9% of isolates from HIV negative cases as compared to 4.4% of isolates from AIDS cases.

Early Diagnosis of Human Immunodeficiency Virus Infection by p24 Antigen Detection

p24 antigen was estimated in human immunodeficiency virus (HIV) sero-negative individuals attending various sexually transmitted diseases (STD) clinics and also in sero-negative voluntary blood donors. A total of 300 STD cases and 500 voluntary blood donors, who also acted as controls, were included in this study. Antibody to HIV was detected by ELISA and was confirmed by western blot. In sero-negative individuals, p24 antigen detection was carried out by standard assay and immune-complex dissociation assay (ICD assay) using ELISA method and confirmation was done by neutralisation assay. In voluntary blood donors, 4 (0.8%) individuals were found to be HIV positive and no sero-negative individual was positive for p24 antigen. 41 out of 300 patients attending STD clinics were found to be positive for HIV and in 259 sero-negative patients, p24 antigen was detected in 6 (2.3%) cases by ICD assay whereas only 4 cases were detected by standard assay. By estimating p24 antigen an additional 2.3% HIV positive cases that were in window period were detected. Further, an ICD assay improves the detection of p24 positive individuals.

COMPARISON OF RAPID METHOD OF DNA EXTRACTION USING MICROWAVE IRRADIATION WITH CONVENTIONAL PHENOL CHLOROFORM TECHNIQUE FOR USE IN MULTIPLEX PCR FOR mec A AND fem B GENES TO IDENTIFY GENOTYPES OF MRSA FROM CULTURES

Methicillin Resistant Staphylococcus aureus (MRSA) infection is a major cause of morbidity and mortality in hospitalised patients and requires vancomycin for effective therapy. Rapid identification of MRSA is vital to control MRSA outbreaks in hospitals. Identification of MRSA is a time consuming process requiring more than 48 hours and is labour intensive involving culture, biochemical tests and antimicrobial susceptibility testing. In this study we have used microwave irradiation of the bacterium obtained from cultures which was then directly subjected to a multiplex PCR technique to accurately and rapidly identify the presence of mec A and fem B genes which characterise MRSA. This has been compared with the standard method of lysing the bacterium and DNA extraction using phenol chloroform method followed by multiplex PCR. The microwave lysis method followed by direct PCR has been found to be less time consuming, 5 hours, as compared to 9 hours by conventional technique. Use of this strategy would enable early identification and early implementation of control measures.

Newer versus Conventional Methods in the Diagnosis of Malaria: A Comparison

BACKGROUND This study attempts to evaluate and compare the efficacy of polymerase chain reaction (PCR) and quantitative buffy coat (QBC) assay with conventional Giemsa stained peripheral blood smear (PBS) examination in the diagnosis of malaria. METHODS The study was conducted on 50 cases of smear positive malaria (group 1), 50 cases of clinically suspected malaria (group 2) and 15 healthy controls. All were subjected to Giemsa stain slide examination both thick and thin smear, QBC assay and PCR. PBS examination by Giemsa stain was taken as gold standard. RESULT In this study the overall sensitivity and positive predictive value (PPV) of QBC assay in group 1 was 100% and that of PCR was 60% and 100% respectively. In group 2 the sensitivity, specificity, PPV and NPV of QBC assay was 100% and that of PCR was 71%, 100%, 100% and 73% respectively as compared to the gold standard. All the 15 healthy controls were negative by all the three assays showing 100% specificity. CONCLUSION QBC assay was an excellent alternative to the conventional method as it is rapid and less time consuming and can directly demonstrate the parasite. Utility of PCR lies in species-specific diagnosis of falciparum malaria especially when there is a high degree of clinical suspicion and the report is negative by the other two methods.

Hepatitis G Virus: Prevalence in Blood Donors in Armed Forces

BACKGROUND A new RNA virus designated hepatitis G virus (HGV) was recently identified. Because HGV has less than 25% sequence or amino acid homology with hepatitis C virus (HCV) and other established Flaviviridae, it is considered to be a new genus in this growing family of hapatotropic viruses. Hepatitis G virus has been associated with hepatitis and is transmitted through parenteral and sexual route. MATERIAL AND METHODS A study comprising 500 healthy voluntary blood donors (service personnel) was under taken to find out prevalence of HGV. HGV RNA was detected by reverse transcriptase - polymerase chain reaction (RT-PCR). Hepatitis B surface antigen (HbsAg) and antibody to HCV were detected by Enzyme Linked Immunosorbent Assay (ELISA). RESULTS Thirteen donors (2.6%) were positive for HGV RNA. 17 donors (3.4%) were positive for antibody to hepatitis C virus (HCV) by ELISA. Co-infection of HGV with hepatitis B virus (HBV) was seen in 5 donors and with HCV infection in 2 donors. Co-infection of HGV, HBV and HCV was not seen in any donor. CONCLUSION So far there is no conclusive evidence that HGV produces hepatitis. But presence of HGV in hepatitis cases casts a doubt on this finding. Prevalence rate in blood donors may be helpful in future studies when the exact role of HGV is known.

Random Amplification of Polymorphic DNA Based Typing of Pseudomonas Aeruginosa

Pseudomonas aeruginosa was isolated from various sources during the course of an epidemic outbreak of bacterial endophthalmitis following an eye camp at Sangli, Maharashtra. 15 distinct isolates were obtained from clinical samples. Typing of the 15 isolates was performed by random amplified polymorphic DNA (RAPD) analysis, pyocin typing and antibiogram. RAPD typing was rapid, labour friendly and could be done within six hours. RAPD analysis produced reproducible electrophoretic band patterns on the basis of which three distinct amplification patterns could be visualised. The conventional typing methods were labour intensive and took about 48 hours. However, the results of RAPD typing, pyocin typing and antibiogram did not correlate with each other. This study suggests that RAPD typing could be an additional rapid typing method for studying the epidemiology of infectious disease outbreaks due to P aeruginosa.

Hepatitis G Virus Infection in Healthy Individuals, Acute Viral Hepatitis and Persons at Risk for Parenteral Transmission

BACKGROUND Hepatitis G virus (HGV), transmitted mostly by parenteral route, has been under investigation for its role as an agent for viral hepatitis. This study was carried out to find out the prevalence of HGV in healthy individuals, multi-transfused patients with acute viral hepatitis and those under going dialysis. METHOD The study included 200 healthy individuals and 180 patients, comprising acute viral hepatitis (100 cases), multi-transfused patients (50 cases) and patients undergoing dialysis (30 cases). HGV RNA and Hepatitis C virus (HCV) RNA was detected by reverse transcription and polymerase chain reaction (RT-PCR) in all. Viral marker studies for hepatitis A, B and E were carried out by ELISA in acute viral hepatitis cases. In healthy individuals, in patients with multiple transfusions or those undergoing dialysis, marker studies for HBV and HCV were carried out. RESULT The prevalence of HGV in healthy individuals was 2.5% (5/200), in non A-E hepatitis 3% (3/100), in multi-transfused patients 4% (2/50) and in patients undergoing dialysis 6.67% (2/30). There was no significant difference in the prevalence rate of HGV infection in healthy individuals and in patients with non A-E hepatitis. CONCLUSION Depending on prevalence rate, HGV could not be implicated as cause of acute viral hepatitis. Persons with parenteral risk factor (multiple blood transfusions and those undergoing dialysis) had higher prevalence rate as compared to healthy individuals.

Potency Titration of Oral Polio Vaccine by Estimation of Live Virus Content Using Tissue Culture Technique

Representative vaccines from 34 different batches of oral log10 (6.425) and a minimum titre of polio vaccine (OPV) were tested for potency by tissue culture technique. All 34 samples were found to be potent, a maximum titre of log10 (6.425) and a minimum titre of log10 (5.86) was obtained. In addition, 6 vaccines from the immunisation clinic (left over sample after immunisation) were also subjected to potency titration and their potency was found to be within normal limits. Adequate potency confirmed ideal storage condition of the vaccines in Armed Forces set up.

HIV — 1 subtypes, its implications and viral dynamics

Subtyping of HIV has important implications for developing candidate vaccine and understanding the biological behaviour and dynamics of HIV transmission in various populations. The third variable region (V3) in the envelope gene of HIV-1 has been shown to be a major determinant influencing a number of biological characteristics of the virus. HIV-1 evolves by rapid mutation and by recombination, both processes actively contributing to its genetic diversity. Most of the multiple genetic subtypes and intersubtype recombination of HIV-1 that comprise the global pandemic have not been characterized by full genome sequencing. The development of an effective human immunodeficiency virus type-1 (HIV-1) vaccine is likely to depend on knowledge of circulating variants of genes other than the commonly sequenced gag and env genes.

ENTERIC FEVER – CULTURE AND SENSITIVITY PATTERN AND TREATMENT OUTCOME

One hundred cases of enteric fever in the age group of 6 months to 12 years were analysed with respect to culture sensitivity pattern and treatment outcome. Patients were divided into 5 treatment groups - chloramphenicol, amoxycillin, trimethoprim-sulfamethoxazole + furazolidine, gentamicin + cephalexin and ciprofloxacin. Out of 91 culture positive cases, 100% were sensitive to ciprofloxacin followed by gentamicin (84.9%), cephalexin (83.6%), furazolidine (36.6%), trimethoprim-sulfamethoxazole (34.1%), chloramphenicol (34.0%) and amoxycillin (23.8%). In 60 cases resistant to chloramphenicol, resistance to other drugs varied from 20 to 88.3%. The treatment response was 100% to ciprofloxacin, 72.7% to chloramphenicol, 50% to gentamicin + cephalexin, 38.5% to trimethoprim-sulfamethoxazole + furazolidine and 12.5% to amoxycillin. Out of 48 cases who did not respond to initial regimen, 33 were treated successfully with ciprofloxacin and remaining with other drug regimens. Time taken for defervescence was shortest with gentamicin + cephalexin (4.6±2.0 days) followed by ciprofloxacin (6.1±2.5 days) and chloramphenicol (6.4±3.5 days). There were 3 deaths in this study.