Catheter-related blood stream infections: prevalence, risk factors and antimicrobial resistance pattern

Background

Intravascular devices have significant potential for producing iatrogenic diseases resulting in catheter-related blood stream infections (CRBSIs). A study was undertaken to find the prevalence of CRBSI among patients in acute wards and to analyze the associated risk factors, causative pathogens with their antibiotic susceptibility (ABST) patterns.

Methods

Randomly ten days per month were chosen, for a period of two years. All the acute wards patients who were on indwelling blood catheters were identified. Those fulfilling the CRBSI criteria were further worked up for confirmation of diagnosis by differential time to positivity. The catheter tip was cultured by Maki's semiquantitative method. ABST of the isolates obtained was performed by Kirby-Bauer disk diffusion method.

Results

The prevalence of CRBSI was found to be 39.25% with the most common organism isolate being Serratia marcescens (23.81%). The immunocompromised status of the patients and catheterisation time were significant risk factors. Methicillin resistance was found to be 33.33% in coagulase-negative staphylococci. The resistance to vancomycin among the Entercoccus faecium isolates was found to be 33.33%. Among the gram negatives, resistance to aminoglycosides, fluoroquinolones and third-generation cephalosporins was high.

Conclusion

The study highlights the importance of regular surveillance programs, an efficient infection control program, strict adherence to antiseptic measures and use of a rational antibiotic policy for the early diagnosis and better management of CRBSI.

Point prevalence & risk factor assessment for hospital-acquired infections in a tertiary care hospital in Pune, India

Background & objectives:

Hospital-acquired infections (HAIs) are a major challenge to patient safety and have serious public health implications by changing the quality of life of patients and sometimes causing disability or even death. The true burden of HAI remains unknown, particularly in developing countries. The objective of this study was to estimate point prevalence of HAI and study the associated risk factors in a tertiary care hospital in Pune, India.

Methods:

A series of four cross-sectional point prevalence surveys were carried out between March and August 2014. Data of each patient admitted were collected using a structured data entry form. Centers for Disease Control and Prevention guidelines were used to identify and diagnose patients with HAI.

Results:

Overall prevalence of HAI was 3.76 per cent. Surgical Intensive Care Unit (ICU) (25%), medical ICU (20%), burns ward (20%) and paediatric ward (12.17%) were identified to have significant association with HAI. Prolonged hospital stay [odds ratio (OR=2.81), mechanical ventilation (OR=18.57), use of urinary catheter (OR=7.89) and exposure to central air-conditioning (OR=8.59) had higher odds of acquiring HAI (P<0.05).

Interpretation & conclusions:

HAI prevalence showed a progressive reduction over successive rounds of survey. Conscious effort needs to be taken by all concerned to reduce the duration of hospital stay. Use of medical devices should be minimized and used judiciously. Healthcare infection control should be a priority of every healthcare provider. Such surveys should be done in different healthcare settings to plan a response to reducing HAI.

Outbreak of Prototheca wickerhamii algaemia and sepsis in a tertiary care chemotherapy oncology unit

BACKGROUND

Prototheca is an emerging, opportunistic, pathogenic, zoonotic achlorophyllous green alga, expanding in pathogenicity and host range, causing localized and disseminated infections. This outbreak of Prototheca wickerhamii algaemia and sepsis in a tertiary care 30-bedded chemotherapy oncology unit is the first human outbreak to the best of our knowledge.

METHODS

P. wickerhamii algaemia was confirmed on consecutive isolation. Person to person transmission was hypothesized considering all patients in the unit at risk. Clinico-demographic, diagnostic and treatment profile were correlated. Both manual and automated systems were used for blood culture, isolation, identification and susceptibility of Prototheca. Liposomal amphotericin B was given. Outbreak surveillance of faeces, fingertips and environmental reservoirs, retrospective surveillance during past 15 years and prospective surveillance was continued for two years.

RESULTS

The outbreak affected 12 neutropenic patients over 50 days. No specific clinical features were noted. The hypothesis could not be substantiated. P. wickerhamii was isolated as yeast-like colonies revealing Gram positive yeast-like cells without budding and pseudohyphae which were confirmed by automated system. Post amphotericin B blood cultures were negative for Prototheca. Surveillance studies were not contributory.

CONCLUSION

P. wickerhamii has no documented reservoirs or transmission. Endogenous colonization in the gut followed by translocation during chemotherapy induced immunosuppression is likely to cause algaemia and sepsis. Outbreaks are difficult to detect and control as incubation period is variable and clinical presentation is muted, emphasizing the need to strengthen hospital and laboratory based surveillance systems to ensure adequate preparedness, rapid detection and response to outbreaks.

Prevalence and molecular characterization of methicillin resistance among Coagulase-negative Staphylococci at a tertiary care center

BACKGROUND

Methicillin-resistant Coagulase-negative Staphylococci (MR-CoNS) have emerged as an important cause of nosocomial infections especially in patients with prosthetic devices and implants. This study was conducted with an aim to determine the prevalence of methicillin resistance among CoNS isolates at a tertiary care center by both phenotypic and genotypic methods.

METHODS

This cross sectional study was carried out from September 2011 to February 2014 in which 150 non-repetitive clinical isolates of CoNS were identified at the species level by conventional phenotypic methods. Cefoxitin disk (30 μg) diffusion testing was used to determine methicillin resistance and confirmed by detection of mecA gene by polymerase chain reaction (PCR).

RESULTS

Out of 150 CoNS isolates, 51 were methicillin resistant by cefoxitin disk diffusion method. Out of these 51 isolates, mecA gene was detected only in 45 isolates. Moreover, mecA gene was also detected in 4 isolates, which were cefoxitin sensitive. Thus, the prevalence of methicillin resistance among CoNS was found to be 32.7% by PCR.

CONCLUSION

The prevalence of methicillin resistance among Coagulase-negative Staphylococci (CoNS) was 32.7% by PCR detection of mecA gene. The sensitivity and specificity of cefoxitin disk diffusion method against mecA gene detection by PCR were found to be more than 90%. It can be concluded from this study that cefoxitin disk diffusion test can be used as a useful screening method to detect methicillin resistance among CoNS isolates. However, detection of mecA gene by PCR remains a more accurate method of detecting methicillin resistance among CoNS.

Detection of glycopeptide resistance genes in enterococci by multiplex PCR

BACKGROUND

Vancomycin Resistant Enterococci (VRE) are a major cause of nosocomial infections. There are various phenotypic and genotypic methods of detection of glycopeptide resistance in enterococci. This study utilizes multiplex PCR for reliable detection of various glycopeptides resistance genes in VRE.

METHOD

This study was conducted to detect and to assess the prevalence of vancomycin resistance among enterococci isolates. From October 2011 to June 2013, a total of 96 non-repetitive isolates of enterococci from various clinical samples were analyzed. VRE were identified by Kirby Bauer disc diffusion method with Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) of all isolates for vancomycin and teicoplanin was determined by E-test. Multiplex PCR was carried out for all enterococci isolates using six sets of primers.

RESULTS

Out of 96 isolates, 14 (14.6%) were found to be resistant to vancomycin by vancomycin E-test method (MIC ≥32 μg/ml). Out of these 14 isolates, 13 were also resistant to teicoplanin (MIC ≥16 μg/ml). VanA gene was detected in all the 14 isolates by Multiplex PCR. One of the PCR amplicons was sent for sequencing and the sequence received was submitted in the GenBank (GenBank accession no. KF181100).

CONCLUSION

Prevalence of VRE in this study was 14.6%. Multiplex PCR is a robust, sensitive and specific technique, which can be used for rapid detection of various glycopeptide resistance genes. Rapid identification of patients infected or colonized with VRE is essential for implementation of appropriate control measures to prevent their spread.

In vitro vancomycin susceptibility amongst methicillin resistant Staphylococcus aureus

BACKGROUND

Vancomycin is drug of choice for treatment of Methicillin Resistant Staphylococcus aureus (MRSA) infections. S. aureus with reduced vancomycin susceptibility (SA-RVS) is on rise. Current guidelines of detection of SA-RVS are based on MIC (Minimum Inhibitory Concentration) by broth or agar dilution methods. Vancomycin MIC by E test (Epsilometer Test) is an alternative. A study was undertaken to know the prevalence of SA-RVS and compare vancomycin MIC by agar dilution and E test.

METHODS

A prospective study was undertaken at tertiary care hospital; 232 clinical MRSA isolates were included. Vancomycin MIC was undertaken by agar dilution method and E test.

RESULTS

All isolates were sensitive to Linezolid. Two MRSA isolates had vancomycin MIC ≥4 μg/ml; vancomycin MIC50 and MIC90 of MRSA isolates was 0.5 and 0.2 μg/ml respectively by agar dilution method. There was agreement over 93.5% isolates in vancomycin susceptibility by agar dilution and E test. E test had sensitivity and positive predictive value of 1.0 (CI - 0.34-1.0) and 0.5 (CI - 0.17-0.83) respectively compare to agar dilution method.

CONCLUSIONS

MRSA isolates continues to be susceptible to vancomycin and Linezolid. E test was found equally suitable in initial screening for vancomycin susceptibility. Due to geographic variation in prevalence, there is need of ongoing surveillance of SA-RVC.

Possession syndrome at high altitude ( 4575 m/15000 ft )

In a first of its kind, a 20 year old Hindu, highlander, working girl presented with abnormal behavior, unrelenting symptoms, had limited benefit by usual treatment and was diagnosed as possession syndrome. Exorcism offered symptomatic relief. The girl resumed normal activities with no recurrence in a 12 month follow up. Possession syndrome is explained in both medical and theological perspectives. Modern medicine associates it with a mental illness though True Possession syndrome without associated mental illness has been reported. Theological perspective can be amalgamated with current scientific theory and practice, thereby complimenting existing concepts.

A Rare Case of Hemoglobin E Hemoglobinopathy with Gaucher's Disease

Hemoglobin (Hb) E mutation is common in north-east part of our country. The natural history of Hb E thalassemia is highly variable. The phenotype, for patients with similar mutations, can range from asymptomatic to transfusion dependent. Our patient presented at 2 years of age with failure to thrive and hepatosplenomegaly. Routine work up revealed microcytic, hypochromic red blood cells. Hb E homozygous was indicated on electrophoresis and hemoglobin HPLC. Evaluation of parents revealed Haemoglobin E trait in both. Therapeutic splenectomy revealed Gaucher-like cells. β-Glucocerebrosidase levels were low. Presence of Gaucher-like cells with normal β-glucocerebrosidase (pseudo-Gaucher cells) are known in leukemia, multiple myeloma, thalassemia and mycobacterial infections. Co-existence of Gaucher's disease with Hb E mutation is not reported to the best of our knowledge.

Usefulness of enzyme immunoassay (EIA) for screening of anti HIV antibodies in urinary specimens: A comparative analysis

BACKGROUND

Standard HIV testing is done using serum or plasma. FDA approved ELISA to screen urine for IgG antibodies to HIV-1 in 1996. It is a simple, noninvasive test and is appropriate for developing countries where health care personnel may not be professionally trained or where clean needles for drawing blood may not always be available.

METHODS

436 individuals with high-risk behavior and strong clinical suspicion of HIV infection were screened for IgG antibodies to HIV-1 in urine by ELISA. Urine HIV testing was performed by enzyme immunoassay, at the ongoing Voluntary Confidential Counseling and Testing Center (VCCTC) at a large tertiary care microbiology lab. The individuals enrolled for the study had high-risk exposure to the virus and majorities were from a state with a high incidence of HIV infection. In all individuals, both serum and urine were tested for IgG antibodies to HIV-1.

RESULTS

Overall, 135 individuals (30.96%) were HIV-positive, of whom 96 (71%) had never previously tested positive; 87% of those who tested positive received their results, and most were referred for medical care. Sensitivity, specificity and predictive values of HIV-1 urine ELISA test kit were determined. Sensitivity was found to be 89.6%; 95% CI [82.9-94.0], specificity 97.3%; 95% CI [94.6-98.8], positive predictive value 93.8%; 95% CI [87.8-97.1] and negative predictive value 95.4%; 95% CI [92.3-97.4].

CONCLUSION

Efficiency, sensitivity, and specificity of the urine-based screening for HIV-1 test kits were excellent as compared to the reference test.

Phenotypic detection of Extended Spectrum Beta-Lactamases and Amp C Beta- Lactamases among nosocomial isolates in a tertiary care hospital

Background & objectives: Extended-Spectrum Beta-Lactamases (ESBLs) is an important resistance mechanism in Enterobacteriaceae infections. Lack of standard guidelines from Clinical Laboratory Standards Institute (CLSI) for Amp C beta-lactamase detection poses a problem. This study was undertaken to detect ESBLs by phenotypic tests and Amp C beta-lactamase by inhibitor based method. Material and Methods: 200 consecutive non-repetitive isolates of E.coli, Klebsiella and Proteus from clinical samples were screened for ESBLs as per CLSI guidelines and confirmed by PCDT, DDST and E-tests (AB Biodisk, Biomerieux). Amp C beta lactamases were screened by cefoxitin resistance and confirmed by inhibitor (Cloxacillin) based method. Simultaneous occurrence of Amp C and ESBLs was detected by combined disk test (Neo-Sensitabs and Diatabs). Descriptive and Kappa statistics were used. Results: Out of 200 isolates studied, 131 were initially screened as ESBL producers and later 114 (57%) were confirmed by phenotypic methods. E-Test was found most sensitive phenotypic test as compared to PCDT and DDST. 13 strains resistant to cefoxitin (30?g) were found to be pure Amp C producers. Combined disk test detected 36 to be ESBL and Amp C co-producers. Surprisingly, six isolates found sensitive to cefoxitin disk were confirmed as Amp C producers by cloxacillin disk inhibition test. Conclusion: 57% ESBLs and 27.5% Amp C producers were isolated from nosocomial pathogens showing significant resistance to 3rd generation cephalosporins. Phenotypic confirmation by E-test, PCDT & DDST were useful for ESBL identification and for detection of Amp C, cloxacillin was found to be an effective inhibitor. DOI: http://dx.doi.org/10.3329/bjms.v12i4.13309 Bangladesh Journal of Medical Science Vol. 12 No. 04 October ’13 Page 378-384

Prevalence of inducible clindamycin resistance in Staphylococcus aureus isolated from clinical samples

BACKGROUND

Therapy for Staphylococcal infections may be complicated by the possibility of inducible macrolide-lincosamide-streptogramin B resistance (MLSBi). We studied the prevalence of MLSBi in community associated (CA) and hospital associated (HA) Staphylococcus aureus isolates from clinical samples.

METHODS

A total of 305 strains of S. aureus comprising 140 (45.9%) [95% CI 40.36-51.52] methicillin resistant S. aureus (MRSA) and 165 (54%) [95% CI 48.48-59.64] methicillin-sensitive S. aureus (MSSA) were identified by conventional methods. The double disc test (D test) was applied by placing erythromycin and clindamycin discs to investigate inducible and constitutive MLSBi resistant phenotypes.

RESULTS

16.6% of MRSA showed constitutive resistance and 37.5% inducible MLSBi resistance. Community associated MRSA (CA-MRSA) represented 10% of all isolates and had lower prevalence of MLSBi than hospital associated MRSA (HA-MRSA).

CONCLUSION

Routine screening for inducible MLSBi resistance by double disc test can screen for potential treatment failures such that clindamycin can be used effectively and judiciously when indicated for staphylococcal infections especially for treating skin and soft tissue infections (SSTIs) in CA-MRSA due to low prevalence of MLSBi among CA-MRSA.

Therapeutic challenges of ESBLS and AmpC beta-lactamase producers in a tertiary care center

BACKGROUND

Resistance to broad-spectrum beta lactams mediated by extended spectrum beta lactamases (ESBLs) and AmpC beta lactamases (AmpC βLs) enzymes is an increasing problem worldwide. Determination of their prevalence is essential to formulate an effective antibiotic policy and hospital infection control measures. Present study was undertaken to determine the prevalence of ESBL and AmpC βL producers in ICU of a tertiary care center.

METHODS

A total of 262 clinical isolates comprising of Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis that were recovered from various clinical specimens over a one year period, were studied. Antibiogram profile was determined to conventionally used antibiotics, along with recommended tests for detection of ESBL and AmpC βL production.

RESULTS

40.07% (105/262) were found to be ESBL producers, 14.8% (39/262) were AmpC bL producers. The coexistence of ESBL and AmpC βL producers was detected in 9.9% (26/262) of the isolates.

CONCLUSION

Screening of multidrug resistant bacteria especially belonging to the Enterobacteriaceae poses considerable therapeutic challenges in critical care patients because of the production of ESBL and AmpC βL. Strategies to keep a check on the emergence of such drug resistant microbes by hospital environmental surveillance and laboratory monitoring should form an important aspect of Hospital Infection control policy guidelines.

Hepatitis B e Antigen Negative Chronic Hepatitis in Indian Patients : A Reality

BACKGROUND

Hepatitis B e antigen negative chronic hepatitis (e(-) CHB) with detectable levels of hepatitis B virus DNA (HBV DNA) in serum has been reported in cases from Asia. This study was undertaken to find out prevalence e(-)CHB and to correlate its presence with the clinical status and severity of the illness in cases of chronic liver disease in India.

METHODS

All patients of infective hepatitis, who were hepatitis B surface antigen (HBsAg) positive by enzyme-linked immunosorbent assay (ELISA), were evaluated with liver function tests and HBeAg and antiHBe antibody studies. Polymerase chain reaction (PCR) test was carried out to detect HBV DNA qualitatively.

RESULT

Out of 2064 samples tested by ELISA, 429 (20.78 %) were HBsAg positive. HBV DNA (qualitative) was performed on all 429 patients and 74 (17.2%) were HBV DNA positive. Of these only 42 (56.75 %) tested positive for HBeAg. Overall, 8.3 % of HBeAg negative patients (32/384) were viraemic with evidence of chronic liver disease/clinical cirrhosis and alteration of transaminase levels, while three cases (0.84 %) HBeAg positive cases did not show presence of HBV DNA.

CONCLUSION

This study shows e(-)CHB prevalence rate of 8.3% in patients with HBV infection in India. Since HBeAg negative patients had detectable levels of HBV DNA as seen in HBeAg positive patients, benefit of antiviral therapy should be given to them. Population studies on e(-) CHB cases are needed to determine its true prevalence, natural course and response to therapy.

Outbreak of Viral Hepatitis E in a Regimental Training Centre

BACKGROUND

An outbreak of viral hepatitis occurred in a regimental centre with 265 cases occurring during a 3 months period.

METHODS

190 serum samples were tested for IgM antibodies against viral hepatitis E by Enzyme Immuno Assay (EIA) and for antibodies against Hepatitis A and Hepatitis B viruses. Epidemiological investigation comprised review of surveillance data, filling up epidemiological case sheet, sanitary survey, inspection of water supplies and bacteriological examination of water for coliforms.

RESULT

97.4% of the serum samples were positive for IgM antibodies against Hepatitis E virus. Two leaks were detected in water pipelines, which were passing through contaminated areas around improperly functioning septic tanks and soak pits. The attack rate among recruits being supplied water through leaking pipelines was 11.1% whereas it was 2.89% in those not directly exposed. This difference was statistically significant (p<0.001). Bacteriological examination of water showed a high coliform count.

CONCLUSION

The outbreak of viral hepatitis E occurred due to sewage contamination of water pipelines.

Outbreak of Rubella Among Cadets in an Academy

BACKGROUND

Rubella is traditionally considered a childhood disease, but has the potential to cause outbreaks in closed community of young adults. The present paper describes one such outbreak in a military training establishment.

METHOD

The cases of rubella outbreak were identified by clinical features (fever, rash and lymphadenopathy) and confirmed by detection of high titre of anti-rubella IgM antibodies by enzyme-linked immunosorbent assay. Initial serum samples were also tested for antibodies against measles, scrub typhus and dengue. Salient epidemiological features of the outbreak were studied.

RESULT

163 cadets were admitted in the local military hospital within two months. The cases presented with fever, coryza, lymphadenopathy and maculopapular rash. 117 (71.78%) of the samples showed presence of anti-rubella IgM antibodies.

CONCLUSION

Rubella outbreaks in military communities have the potential to adversely affect military training/operations. The need for administration of vaccination against rubella in such population may be reviewed.

Detection of Bacterial Pathogens in Cerebrospinal Fluid using Restriction Fragment Length Polymorphism

BACKGROUND

Polymerase chain reaction (PCR) is useful for rapid microbial detection in body fluids with low microbial load. It is easier to use universal or broad range primers for the amplification of conserved stretches of DNA common to all bacteria like 16S rRNA gene, followed by restriction fragment length polymorphism (RFLP) of PCR products.

METHODS

Forty samples of cerebrospinal fluid were collected. After DNA extraction, universal or broad range PCR was performed using two universal primers U1-5'-CCAGCAGCCGCGGTAATACG-3', corresponding to nucleotides 518 to 537 of the Escherichia coli 16S rRNA gene, and U2 - 5'-ATCGG(C/T)TACCTTGTTACGACTTC-3', corresponding to nucleotides 1513 to 1491 of the same gene. The PCR product was subjected to digestion by endonucleases- HaeIII, Mn11, BstB1 and Alu1. Restriction pattern obtained was compared with that of standard organisms to identify the pathogen. The results were compared with conventional methods.

RESULT

Universal PCR could detect pathogens in 20% samples within 13-18 hours as compared to 16% by conventional methods. The analytical sensitivity was 10 Gram negative and 250 Gram positive organisms per 200 μl sample. Overall sensitivity was 83.3% and specificity was 91.2%.

CONCLUSION

Universal PCR followed by RFLP of PCR product is a good alternative to conventional diagnosis of bacterial pathogens.

Evaluation of a commercial Dengue NS1 enzyme-linked immunosorbent assay for early diagnosis of dengue infection

PURPOSE

Dengue is one of the most serious mosquito-borne viral infections affecting tropical and subtropical countries in the world. Since there is no immunoprophylactic or specific antiviral therapy available, timely and rapid diagnosis plays a vital role in patient management and implementation of control measures. This paper evaluates a commercially available NS1 antigen capture ELISA vis-a-vis SD bioline Dengue NS1 antigen test for early detection of dengue virus.

MATERIALS AND METHODS

To evaluate a commercial NS1 antigen detection kit vis-a-vis SD bioline Dengue NS1 antigen test, a total of 91 clinical samples were tested. Virological investigations with regard to dengue virus, viz. NS1 antigen capture ELISA (Panbio, Australia), SD bioline Dengue NS1 antigen test, RT-PCR and virus isolation were performed.

RESULTS

Out of 91 samples, 24 (26%) were positive by NS1 antigen capture ELISA, 15 (16%) by SD bioline Dengue NS1 antigen test and 11(12%) positive by RT-PCR analysis. The RT-PCR-positive samples were further subjected to virus isolation and resulted in three isolates. The results of the Panbio NS1 antigen capture ELISA, SD bioline Dengue NS1 antigen test, RT-PCR and virus isolation were correlated among themselves.

CONCLUSIONS

The present study comprehensively established the utility of NS1 antigen ELISA in early diagnosis of dengue infection.

Divergent strains of human immunodeficiency virus type 1 circulating in India, subtyped by heteroduplex mobility assay

Genomic variations in HIV-1 represent a major problem in understanding disease progression, studying drug resistance and developing effective vaccines. Heteroduplex Mobility Assay (HMA) was used for analyzing HIV-1 subtypes resulting from genetic similarity or divergence of C2 -V3 -V5 region of envelope gene between HIV-1 strains obtained from clinical samples in a tertiary care center at Pune. DNA from the PBMCs of infected individuals was amplified by nested PCR. Heteroduplexes were then formed by denaturing DNA from the unknowns with DNA from the reference strains. The results were analyzed by polyacrylamide gel electrophoresis. Out of 177 samples analyzed, 170 were of subtype C (96%). Four samples were found to be of subtype B (2.2%); in three samples, no definitive assignment of subtype was possible by HMA and these perhaps could be circulating recombinant forms (CRFs) of HIV-1. These findings may have significant implications toward development of a candidate vaccine for India.

Identification of Human Immunodeficiency Virus Type-1 Subtypes by Heteroduplex Mobility Assay

BACKGROUND

Human immunodeficiency virus type-1 (HIV-1) has developed marked genomic sequence differences over the course of an epidemic because of an error prone reverse transcriptase (RT), which rapidly incorporates mutations resulting in genomic diversity, altered cell tropism, immune escape and variable resistance to antiretroviral drugs. The best preventive strategy for HIV control is development of an efficacious prophylactic vaccine using the most appropriate (antigenically related) subtypes. On the basis of phylogenetic analysis, HIV strains can be separated into major group "M" consisting of genetic subtypes A-K, "N", the new group and "O", the outlier group.

METHODS

Heteroduplex mobility assay (HMA) is a rapid, economical and reliable technique of subtyping HIV-1. It is based on the principle of determining the genomic relatedness and divergence of the unknown sample with the known reference plasmid HIV-1 subtypes by studying the mobility patterns of the resulting heteroduplexes formed on the polyacrylamide gel.

RESULT

A total of 70 HIV-1 seropositive samples obtained from service personnel, their families and civilians from service hospitals were analyzed and their subtype distribution studied. 66 (94.28%) were HIV-1 subtype C and two (2.85%) subtype B. In two (2.85%) samples, the subtype distribution was homotypic recombinant, one each of subtype C1 & C2 and C2 & C4 respectively.

CONCLUSION

Service personnel and their families represent a divergent population from different regions of India. An analysis of subtypes in these HIV-1 seropositive individuals will help in understanding the geographical distribution and evolution of the virus. Determination of HIV-1 subtypes has significant implications for development of candidate vaccine for India.

Comparison of a dipstick dot-ELISA with commercial assays for anti-dengue virus IgM antibodies

Dengue virus infections have undergone dramatic expansion in range, affecting several tropical and subtropical regions of the world. Dengue virus causes life-threatening complications characterized by dengue hemorrhagic fever and dengue shock syndrome. No standard validated test systems are available for serological diagnosis of dengue virus infection. This creates problems in the diagnosis and proper management of patients. Evaluation of a Defense Research and Development Establishment (DRDE) dengue virus dipstick dot-ELISA test, developed in house, vis-à-vis commercially available immunodiagnostic kits was carried out for detection of IgM antibodies. The DRDE dengue dipstick dot-ELISA was performed on the basis of the dot-ELISA principle. Commercial tests, namely, the Panbio Dengue IgM Capture ELISA system (Panbio, Sinnamon Park, Australia) and Pathozyme Dengue M (Omega Diagnostics, Alva, UK), were performed according to the manufacturers' protocols. Ninety-one serum samples collected from the states of Kerala and Delhi, India during August and November of 2004 were used in the present study. The overall agreement among all three tests was found to be only 72.16% for IgM antibodies. Correlations between the DRDE dipstick dot-ELISA and the Panbio kit, between the DRDE dipstick dot-ELISA and the Pathozyme Dengue M kit, and between the Panbio kit and the Pathozyme Dengue M kit were found to be 96, 93, and 94%, respectively. Although the Panbio kit is widely used in various laboratories in India, the DRDE dipstick dot-ELISA promises to be a useful kit because of its field applicability and comparable sensitivity.

Detection of Human Immunodeficiency Virus Type 1 (HIV-1) A/AE Circulating Recombinant Form (CRF) in India: Possible Implications

BACKGROUND

Rapidly evolving viruses such as human immunodeficiency virus (HIV-1) develop marked sequence differences in their genome over the course of an epidemic and in individuals infected for longer duration. This is because of the error prone reverse transcriptase (RT), which rapidly incorporates mutations resulting in genomic diversity, altered cell tropism, immune escape, and variable resistance to antiretroviral drugs. As a result, radically different genomic combinations may be generated in individuals infected by genetically diverse viruses that have mosaic genomes.

METHODS

Whole blood sample was collected from 25 HIV-1 infected patients. Chromosomal DNA was isolated from the patient's peripheral blood mononuclear cells (PBMCs). Full-length gag gene (~1.5 kb) was amplified. PCR products were subjected to direct automated sequencing. For identification of recombinants Simplot version 2.5 was used.

RESULTS

Out of 25 gag genes that were sequenced, the gene amplified from a 29 years old HIV-1 seropositive male revealed a putative recombinant sequence. This sequence showed maximum homology with HIV-1 subtype A. Simplot analysis revealed the sequence to be a likely recombinant with the following composition: Initial stretch of 1 to 200 nucleotides representing AE circulating recombinant form (CRF), 201 to 440 nucleotides representing HIV-1 subtype A, 441 to 660 nucleotides representing AE CRF again, 661 to 700 nucleotides representing HIV-1 subtype A and the remaining stretch of the nucleotides from 701 to 1076 representing AE CRF.

CONCLUSION

We document a putative HIV-1 subtype A/ AE CRF. It is important to monitor various CRFs that are being generated and horizontally spread in the community. This has significant implications for development of candidate vaccine for India.

Development and evaluation of reverse transcription-loop-mediated isothermal amplification assay for rapid and real-time detection of Japanese encephalitis virus

The standardization and validation of a one-step, single-tube accelerated quantitative reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay is reported for rapid and real-time detection of Japanese encephalitis virus (JEV). The RT-LAMP assay reported in this study is very simple and rapid; the amplification can be obtained in 30 min under isothermal conditions at 63 degrees C by employing a set of six primers targeting the E gene of JEV. The RT-LAMP assay demonstrated exceptionally higher sensitivity compared to that of RT-PCR, with a detection limit of 0.1 PFU. The specificities of the selected primer sets were established by cross-reactivity studies with other closely related members of the JEV serocomplex as well as by evaluation of healthy human volunteers. The comparative evaluation of the RT-LAMP assay for clinical diagnosis with a limited number of patient cerebrospinal fluid samples revealed 85% concordance with conventional RT-PCR, with a sensitivity and a specificity of 100% and 86%, respectively. The concentration of virus in most of the clinical samples was 10(2) to 10(5) PFU/ml, as determined from the standard curve based on the time of positivity in the samples. In addition, the monitoring of gene amplification can also be visualized with the naked eye by using SYBR green I fluorescent dye. Thus, due to easy operation without a requirement of sophisticated equipment and skilled personnel, the RT-LAMP assay reported here is a valuable tool for the rapid and real-time detection of JEV not only by well-equipped laboratories but also by peripheral diagnostic laboratories with limited financial resources in developing countries.

Early detection of HIV-1 in infants by PCR

Infants of HIV-infected mothers are at great risk of becoming infected with HIV during childbirth. Many infants acquire HIV during labor and delivery. Others can acquire HIV through the mixing of fetal and maternal blood as the placenta separates. The duration of membrane rupture, acute chorioamnionitis and invasive delivery techniques that increase the baby's contact with the mother's blood have been associated with higher risks of MTCT during labor and delivery. HIV is present in breast milk and risk of its transmission during breastfeeding depends on several factors, including: infant age, pattern of breastfeeding, breastfeeding duration, breast health, maternal viral load and maternal immune status. Infants born to HIV infected mothers carry their mother's antibodies in their blood into the second year of life, even if the infants themselves are not infected. For this reason, standard HIV antibody tests cannot reliably confirm HIV infection in infants until after the maternal antibodies have disappeared. Tests that can diagnose pediatric HIV infection accurately during the first year of life include HIV-PCR, CD4/CD8 counts, P24 antigen tests, and viral cultures. PCR offers an effective tool to reliably diagnose HIV in a pediatric age group. Nineteen infants born by normal delivery to HIV-1 seropositive mothers were studied by PCR for the HIV1 env gene. Thirteen babies (68.5%) were negative whereas 6 babies were found to be positive (31.5%). Although PCR is one of the most useful tests for this clinical situation, it is not definitive. Therefore, PCR should be interpreted with caution and repeated at regular defined intervals, preferably lasting until the HIV antibody status of the infant is resolved.

Genomic diversity of human immunodeficiency virus type-1 in India

Surveillance of HIV-1 subtypes has important implications for the development of candidate vaccine and understanding the possible differences in the transmission and natural history of different subtypes. In this study, HIV-1 subtypes were determined for homologies in the C2-V3-V5 region by heteroduplex mobility assay (HMA) in HIV-1 seropositive patients referred to the National HIV/AIDS Reference Centre, All India Institute of Medical Sciences in New Delhi, India. Of the 125 samples analysed, 98 (78.4%) were HIV-1 subtype C, 11 (8.8%) were subtype B', 3 (2.4%) were subtype A and 2 (1.6%) were subtype E. In 11 samples, subtype determination was not clear-cut. It is possible that these individuals may be infected with recombinant strains of HIV-1. These findings may have significant implications for the designing and testing of effective HIV-1 vaccine candidate in India.

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.

A comparison of organisational climates of public and private hospitals abroad

Are organisational climates in private hospitals compared to public hospitals, more favourable? To assess the differences, motivational orientations, perceived satisfaction with intrinsic aspects of the job, professional commitment orientations and perceived organisational climates by the medical professionals, senior administrative and professional nursing personnel are compared. All the groups in the public hospital tended to be higher in motivational orientations. On the other hand, all the groups in private hospital showed higher satisfaction with intrinsic aspects of the job, professional commitment orientations, and perceived favourableness of the organisational climate. The differences were found to be not significant.