Manisha Singh

Abstract

Introduction: Dengue infection is one of the most common arboviral infection in India transmitted by the aedes mosquitoes. Early diagnosis of the infection is often missed if only the antibodies are tested. In this scenario detection of the NS1 antigen has gained importance which has very high specificity and can be detected from the first day of fever. Rapid immunochromatographic tests for the detection of both NS1 antigen as well as the IgM and IgG antibodies have been extensively used in the diagnosis of dengue infection because of the ease of performing when compared to ELISA testing. The present study aims in identifying various dengue markers in the early diagnosis of dengue fever. Materials and Methods: All the suspected dengue samples obtained in the Department of Microbiology were tested by rapid immunochromatography test for the detection of NS1 and IgM/IgG antibodies. Platelet counts were detected by automated analyzer and history and duration of fever has been taken. Results: A total of 1021 samples were tested for dengue infection out of which 158(15.4%) were positive for one or more of the dengue serology markers. Out of the 158, 85(53.79%) were positive only for NS1 antigen indicating the infection in the early stage, 60(37.97%) samples showed only IgM dengue antibodies and 6(3.79%) samples showed only IgG antibodies. Two serological markers are seen in 7 samples, out of which 4(2.53%) samples were positive for NS1+ IgM antibodies and the remaining 3(1.89%) samples for IgM+IgG antibodies. Majority of the cases were in the age group of 16-30 years and males were predominantly affected when compared to females. Decreased platelet count was observed in 62 out of 158 cases (39.2%). Maximum NS1 positivity was observed form 2nd to 7th day of fever where as IgM positivity was maximum between 7th to 9th day. Conclusion: Early diagnosis of dengue infection is warranted by the detection of NS1 antigen. Detection of NS1 antigen along with the IgM/IgG will identify the maximum number of dengue cases. Rapid immunochromatography tests have been extremely useful in the diagnosis of these dengue markers. Keywords: NS1 antigen, Dengue, Serological markers.

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Abstract

Introduction: Oxidase negative nonfermenters are increasingly being isolated from the clinical specimens. Organisms like acinetobacter have been associated with multidrug resistance which makes the treatment difficult. Proper identification and determination of the antibiogram will help in appropriate management of the patients. Aims and Objectives: The study aims to isolate the oxidase negative gram negative bacilli from the clinical specimens and identify them up to the species level and to know the antibiotic susceptibility pattern of these isolates. Materials and Methods: All the clinical specimens obtained in the microbiology department were processed according to the standard protocols. Organisms were isolated and identified by using conventional biochemical testing methods. Antibiotic susceptibility was done by Kirby Bauer disc diffusion testing following the CLSI standards. Results: A total of 153 oxidase negative NFGNB were isolated from the clinical specimens. Out of these Acinetobacter species constituted 146(95%) of the total isolates and the remaining 7(4.5%) were identified as Stenotrophomonas maltophila. The most common species of Acinetobacter isolated was Acinetobacter baumannii complex (Acb- complex), accounting 107(70%) of the total isolates followed by A.lowffii 25(16%), A. junii 10 (7%) and A.hemolyticus 4(2.7%). Majority of the Acb-complex were isolated from respiratory secretions (50.4%) followed by pus samples (30.8%). Stenotrophomonas species were also isolated predominantly from respiratory secretions (71.4%). The most effective antibiotic against these NFGNB were polymyxin B (98% sensitive) followed by tigecycline (96% sensitive). Cotrimoxazole retained its susceptibility against Stenotrophomonas maltophila with all the isolates being susceptible. Conclusion: Speciation of oxidase negative NFGNB has gained importance because of the diverse species involved and their varied antibiogram patterns. Identifying the etiological agents and their susceptibility patterns will help in the better management of patients and reduces mortality and morbidity associated with these infections. Keywords: Non fermenters, Acinetobacter, Drug resistance.

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