than microscopy, rapid, cheap, easy to perform and does not need ... 2013, IP: 120.59.39.214] || Click here to download free Android application for this journal ...
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Indian Journal of Medical Microbiology
*Corresponding author (email: ) Received: 22-05-2013 Accepted: 23-08-2013
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Sherman GG, Stevens G, Jones SA, Horsfield P, Stevens WS. Dried blood spots improve access to HIV diagnosis and care for infants in low-resource settings. J Acquir Immune Defic Syndr 2005;38:615-7. Stevens W, Sherman G, Downing R, Parsons LM, Ou CY, Crowley S, et al. Role of the laboratory in ensuring global access to ARV treatment for HIV-infected children: consensus statement on the performance of laboratory assays for early infant diagnosis. Open AIDS J 2008;2:17-25. Jacob SM, Anitha D, Viswanath R, Parameshwari S, Samuel NM. The use of dried blood spots on filter paper for the diagnosis of HIV-1 in infants born to HIV seropositive women. Indian J Med Microbiol 2008;26:71-4. Susanna C, Fulvio E, Davide B, Richard L, Mamy AP, Giovanna P, et al. Evaluation of different deoxyribonucleic acid (DNA) extraction methods using dried blood spot for
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early infant diagnosis of HIV1 in Sub-Saharan Africa. Afr J Microbiol Res 2012;6:5609-17. Nsojo A, Aboud S, Lyamuya E. Comparative evaluation of amplicor HIV-1 DNA test, version 1.5, by manual and automated DNA extraction methods using venous blood and dried blood spots for HIV-1 DNA PCR testing. Tanzan J Health Res 2010;12:229-35. Piwowar-Manning E, Lugalia L, Kafufu B, Jackson JB. Comparison of results obtained with amplicor HIV-1 DNA PCR test version 1.5 using 100 versus 500 microliters of whole blood. J Clin Microbiol 2008;46:1104-5.
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Weak positive band by immunochromatographic test in pregnancy-associated malaria: A diagnostic dilemma Dear Editor, Malaria in pregnancy is a major cause of morbidity and mortality in developing countries.[1] About 25% of total maternal death is estimated to be caused due to this infection in the malaria endemic zone.[1] Microscopy remains the gold standard for its diagnosis. But with the advent of science, immunochromatographic test (ICT) became more popular and this technique remains the main stay for malaria diagnosis. ICT is more sensitive than microscopy, rapid, cheap, easy to perform and does not need expertise. During pregnancy, majority of the parasitic forms sequester into the placenta rather than in the peripheral circulation, thereby, giving a false negative result by microscopy.[2,3] Hence, for the diagnosis of pregnancy-associated malaria, ICT is preferred.[1] But many reports have highlighted about the false positive result generated by ICT strips.[4] This report highlights the false positive results by ICT strips inconditions like pregnancy, which can create a diagnostic dilemma. A 29-year-old female (G2 P1 L0 A0, with 32 weeks of pregnancy) was admitted to our hospital with complaints of intermittent high-grade fever with chill and rigor for 2 weeks. Her haemoglobin concentration was 9.0 gm%, Total leucocyte count (TLC) 10,900/ml, Platelet count
314,000/ml. The patient became afebrile after she got admission to the hospital. Urine culture sensitivity, Widal serology, Venereal Disease Research Laboratory (VDRL) and hepatitis B antigen were negative. There was no history of malaria diagnosis outside the hospital or antimalarial intake during this period. Blood sample was sent for the malaria serology 2 days after hospital admission. ICT (SD Biloine Malaria antigen Pf/Pan) for malaria serology found to have a faint positive band at Pan area suggesting P. vivax infection. The sample was also processed for microscopy [includes geimsa, acridine orange stain and quantitative buffy coat assay (QBC)], antibody test, polymerase chain reaction (PCR) and with a 2nd ICT (J Mitra, Advantage Mal Card). The sample was found negative for the entire panel of tests except the 2nd ICT in which two faint bands appeared showing positive for both P. vivax and P. falciparum. A diagnosis of malaria due to P. vivax was made and antimalarial treatment was initiated which included Chloroquine 600 mg stat followed by 300 mg after 8 hrs, then 300 mg daily for next 2 days. After completion of treatment, the blood sample was repeated for all the tests. The results found to be exactly same as previous with faint bands in both the ICT strips. The patient remained afebrile for next 4 days after which she was discharged with an advice to follow up.
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Discussion ICTs are very useful tests in the diagnosis of pregnancy-associated malaria.[2] Most of these tests are having sensitivity and specificity more than 90%.[2] It is not a quantitative test, but the intensity of the test band indirectly signifies the number of asexual parasitic forms present in the blood circulation. The colour of the test band can be compared with that of control band and graded as 3+ (≥ control band) to 1+ (faint).[5] In the above case, the sample was faint positive by both the ICTs before and after administration of antimalarial therapy. It was found negative by both microscopy and molecular methods. Moreover, the QBC is found to be negative for all the parasitic forms as well as the pigment containing mononuclear cell, which persists for few days after clearance of parasites. This suggests that the faint band might be appeared falsely because of some nonspecific antibodies in the blood sample.[5] We know that, during pregnancy, there may be presence of certain nonspecific antibody such as rheumatoid factor etc., that can cross react with the immunoglobulin of ICT strip giving false positive result. The risk of false positivity increases with a less intense band. Hence, we suggest, during pregnancy, blood sample with weak positive band by ICT strip should be confirmed by another method (i.e., microscopy or molecular method) before a malaria diagnosis is made.
Interdiscip Prospect Infect Dis 2009;2009:415953. Leke RF, Djokam RR, Mbu R, Leke RJ, Fogako J, Megnekou R, et al. Detection of plasmodium falciparum antigen histidine rich protein-2 in the blood of pregnant women: Implication against placental malaria. J Clin Microbiol 1999;37:2292-6. Mishra B, Samantaray JC, Kumar A, Mirdha BR. Study of false positivity of two rapid antigen detection test for diagnosis of Plasmodium falciparum malararia. J Clin Microbiol 1999;37:1233. Bell D, Go R, Miguel C, Walker J, Cacal L, Saul A. Diagnosis of malaria in a remote area of Phillipines: Comparison of techniques and their acceptance by health workers and the community. Bull World Health Organ 2001;79:933-41.
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*S Mohapatra, M Deb, JC Samantaray, A Ghosh Department of Microbiology (SM, MD), Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, Department of Microbiology (JCS, AG), All India Institute of Medical Sciences, New Delhi, India *Corresponding author (email: ) Received: 06-05-2013 Accepted: 22-08-2013
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Schantz-Dunn J, Nour NM. Malaria and pregnancy: A global health perspective. Rev Obstet Gynecol 2009;2:186-92. Murray CK, Bennett JW. Rapid diagnosis of malaria.
DOI: 10.4103/0255-0857.118886
In-vitro susceptibility to colistin and tigecycline in New Delhi metallo-betalactamase-1 producing Enterobacteriaceae Dear Sir, Carbapenem–resistance in Enterobacteriaceae is mediated by the New Delhi metallo-beta-lactamase (NDM) and was first reported in a patient hospitalized in New Delhi, India, in 2007.[1] Colistin and tigecycline have excellent bactericidal activity against most gram-negative aerobic bacilli. This study was conducted to evaluate the in-vitro activity of colistin and tigecycline against NDM-1 producing Enterobacteriaceae. A total of 97 carbapenem–resistant non-repetitive isolates were collected and the presence of NDM-1 gene was detected in 44 isolates in a previous study.[2] These isolates were K. pneumoniae (n = 26), E. coli (n = 16),
Enterobacter aerogenes (n = 1) and Enterobacter cloacae complex (n = 1). The resistance to carbapenems was confirmed by MIC assays using automated system (VITEK 2C, Marcy l’Etoile, France). The in-vitro activity of colistin and tigecycline against these NDM-1 producing isolates were analyzed using E-strips (AB bioMerieux, Solna, Sweden) and VITEK 2C, AST-GN 25 cards (bioMexrieux) according to the manufacturer’s guidelines and were interpreted by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria and the U.S. Food and Drug Administration (FDA) criteria, respectively.[3,4] The MICs of tigecycline and colistin for NDM-1
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