Evaluation of two test-kits — API and Oxi Ferm tube — for identification of oxidative-fermentative gram-negative rods (original) (raw)
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Journal of Clinical Microbiology, 1989
The Titertek-NF (TT-NF) system (Flow Laboratories GmbH, Meckenheim, Federal Republic of Germany) was evaluated for the identification of 1,289 strains of gram-negative, nonfermentative bacteria and some gram-negative, oxidase-positive bacteria. The oxidase test was also performed. Identifications were classified as correct, not identified (two or more taxa possible and identification score of less than 80%; supplementary tests for furthering the identification were not performed), and incorrect. Correct identification results were further subdivided by the correct level of species or biotype identification as greater than or equal to 98% (category a), 90 to 97% (category b), and 80 to 89% (category c). When compared with conventional identification results, the TT-NF system correctly identified 90.3% of strains (1,164 of 1,289 strains), with 72.5% (935 strains) belonging to category a, 14.7% of strains (189 strains) belonging to category b, and 3.1% of strains (40 strains) belonging...
Rapid identification of nonfermentative gram-negative rods by the Corning N/F system.
Journal of Clinical Microbiology
A total of 1,298 nonfermentative gram-negative rods were used to evaluate the performance of the individual biochemical tests in the N/F System and to determine whether the observed results included sufficient key reactions for rapid identification. The system included an oxidase test, two screening tubes providing 5 test reactions designed primarily to identify pigment-producing strains of Pseudomonas aeruginosa, and a plate providing 12 test reactions designed to identify other nonfermenters. With both the tubes and plates, most results were consistent with expected conventional test reactions. Use of the tubes permitted the identification of 90% of the strains of P. aeruginosa in 24 h and 97% in 48 h. Use of the plates permitted the identification of 95% of the other oxidative nonfermenters within 24 h and 96% within 48 h. Only 26% of weak and nonoxidative nonfermenters were identified because of the nonreactivity of these organisms in this system. There were no misidentifications based on misleading test results.
A Mini-Review on Commonly used Biochemical Tests for Identification of Bacteria
International Journal of Research Publications
Bacteria are pathogenic microorganisms causing a number of diseases in humans from light to life threatening conditions. For proper treatment of patients infected with these diseases require proper diagnosis of diseases causing bacterial agent. As the bacteria are divided into two main as Gram Positive and Gram Negative Bacteria. Both type of bacteria exhibit a number of inherited biochemical properties by which we can differentiate, can check there presence and absence, can check their gram negative and gram positive nature. Therefore, the present review is focused to describe different biochemical tests in one article.
IP innovative publication pvt. ltd, 2019
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.
Rapid and accurate identification of bacterial pathogens is a fundamental goal of clinical microbiology. The diagnosis and surveillance of diseases is dependent, to a great extent, on laboratory services, which cannot function without effective reliable reagents and diagnostics. Despite the advancement in microbiology diagnosis globally, resourcelimited countries still struggle to provide an acceptable diagnosis quality which helps in clinical disease management and improve their mortality and morbidity data. During this study an indigenous product, Quick Test Strip (QTS) NE, was developed for the rapid identification of biochemically slower group of Gram-negative oxidase-positive bacilli that covers 19 different bacterial genera. Some of the members belonging to these groups are well-established human pathogens, e.g. various species of Vibrio, Pseudomonas, Burkholderia, Aeromonas, Achromobacter and Stenotrophomonas. This study also evaluates the performance of QTS-NE by comparing with genotypic characterization methods. A total of 232 clinical and reference bacterial isolates were tested by three different methods. QTS-NE provides 100% concordant results with other rapid identification and molecular characterization methods and confirms the potential to be used in clinical diagnosis.
Journal of Clinical Microbiology, 2003
We have evaluated over a period of 18 months the use of 16S ribosomal DNA (rDNA) sequence analysis as a means of identifying aerobic gram-positive rods in the clinical laboratory. Two collections of strains were studied: (i) 37 clinical strains of gram-positive rods well identified by phenotypic tests, and (ii) 136 clinical isolates difficult to identify by standard microbiological investigations, i.e., identification at the species level was impossible. Results of molecular analyses were compared with those of conventional phenotypic identification procedures. Good overall agreement between phenotypic and molecular identification procedures was found for the collection of 37 clinical strains well identified by conventional means. For the 136 clinical strains which were difficult to identify by standard microbiological investigations, phenotypic characterization identified 71 of 136 (52.2%) isolates at the genus level; 65 of 136 (47.8%) isolates could not be discriminated at any tax...
Comparison of Some Bacterial Identification Methods
2019
Objective: In this study, three different methods were compared for the identification of some Gram positive and Gram negative reference bacteria. Materials and Methods: For this purpose the identification accuracy rates of Enterococcus faecalis, Enterococcus faecium, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens were analysed by conventional bacteriological methods, commercial bacterial identification test kit (Microgen™ ID) and automated bacteria identification system (BD Phoenix 100™). Results: As a result of analyses, the identification accuracy rates of examined cultures were 94.5%, 95.2%, 94.6%, 89.6%, 91.1%, 92.5%, 86.9%, 96.4% by conventional bacteriological methods, 93.84%, 89.2%, 98.86%, 96.55%, 97.98%, 95.43%, 86.69%, 92.39% by commercial bacterial identification test kit and 98%, 99%, 99%, 96%, 96%, 97%, 99%, 98% by automated bacteria identification system, respectively. Conclusion: ...
2013
This experiment displays a common method for indentifying an unknown microbial species-biochemical characterization. A series of biochemical tests were performed on an unknown species of enterobacteriaceae and the results were compared to results of the same tests as previously performed and recorded on various other organisms. The biochemical tests that are discussed in detail below provide information about the unique biochemical processes that a microbe possesses. In this experiment we tested for sugar fermentation, citrate utilization, mixed acid fermentation, 2,3-butanediol fermentation, nitrate reduction, phenylalanine deamination, urea hydrolysis, gelatin hydrolysis, sulfur reduction, motility, and indole production. Each of these tests has unique media and reagents that are used to visualize and interpret the results. The results from this experiment provided sufficient evidence to conclude that the unknown species was indeed Enterobacter aerogenes and many enzymes that work within this organism were displayed and confirmed.