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UNIVERSITY OF PORT HARCOURT
FACULTY OF SCIENCE
DEPARTMENT OF MICROBIOLOGY
A REPORT ON IDENTIFICATION OF
UNKNOWN ISOLATE
PRESENTED
BY
EDAMKUE ISRAEL
U2016/
COURSE TITTLE: INTRODUCTION TO MICROBIOLOGY
COURSE CODE: MCB 200.
COURSE COORDINATOR: Dr. (Mrs.) C. N. ARIOLE
MARCH, 2018.
ABSTRACT
The organism, specimen “B” went through various tests done in the laboratory to determine which organism it was. Nine (9) tests were carried out on the organism to test different biochemical reactions would take place in order to aid identification of the organism specimen B.
Tests included catalase test(to determine the presence of catalase enzyme in the organism), motility test(to determine if the organism is motile), citrate test(to determine if the organism is able to utilize citrate), TSIA (triple sugar iron agar test which was carried out to determine if the organism produces hydrogen sulphide-H 2 S, which is oxidized to FeS), Indole test(o determine if the organism reacts to kovac’s reagent), Sugar fermentation i.e. fermentation of lactose, sucrose and glucose(to determine if the organism is able to ferment sugar to produce an acid and/or a gas), starch hydrolysis(o determine if the organism hydrolyses starch) and MRVP(methyl red and voges-proskauer tests to determine if the organism produces acidic or neutral products). Form the observation and results gotten from the biochemical tests carried out, the unknown organism B was identified to be Proteus vulgaris.
INTRODUCTION
The bacteria discovered after tests was found to be Proteus vulgaris.
NORMAL ENTERIC FLORA
Enteric flora (a mixture of bacteria of enteric origin) causes problems for clinicians and microbiologists alike. Proteus vulgaris is a commensal of the normal flora of the human gastrointestinal tract, but also can be found in water and soil. There are opportunistic pathogens that can infect the lungs, or wounds, and frequently cause urinary tract infections. The bacteria that are found in enteric flora hardly ever cause superficial wound infections (particularly in immunocompetent patients), and even when they do, the laboratory cannot possibly be of any help here
organism if it becomes pathogenic. An organism is identified in order to establish methods of treatment of the disease(s) caused by the organism.
MATERIALS AAND METHOD
- CITRATE TEST MATERIALS: Inoculating needle and loop, sterilizing flame, test tubes, containing citrate medium and unknown organism METHOD: i. The wire loop was sterilized and a loop full of the organism was streaked back and front across the slant. ii. The culture was incubated at 37o^ C for 48 hours in the presence of air. iii. The colour change of the culture was recorded.
- CATALASE MATERIALS: H 2 O 2 , glass slide, inoculating loop, the unknown organism. METHOD: i. The loop was sterilized using dry heat ii. A drop H 2 O 2 was placed on the slide iii. A loop full of organism specimen was placed on the H 2 O 2 on the slide. iv. The bubbles formed were observed and recorded.
- (^) TSIA MATERIALS: Inoculating needle and loop, test tubes, sterilizing flame, TSIA slant METHOD: i. The loop was sterilized using dry heat. ii. With the aid of an inoculating needle, the unknown was pierced into the medium. iii. The unknown was also streaked across the surface. iv. The organism was then left for 48hours, after which observations were recorded.
- INDOLE MATERIALS: Inoculating loop, Peptone water medium, sterilizing flame, unknown specimen, test tube. METHOD: i. A culture of unknown was prepared in peptone ater broth (tryptophan) and left for 48 hours ii. After 48 hours, 5 drops of Kovac’s reagent were added iii. The observation as recorded
- MR-VP MATERIALS: Inoculating loop, unknown specimen, sterilizing flame, MR-VP broth, 40% KOH, 16% alpha napthol. MEHOD: i. A culture of the unknown (inoculated into MRVP) was prepared and left to stay for 48hous. ii. A change was observed and recorded iii. After 48hours the broth was divided into two iv. Into half of it, 5 drops of MR was added v. Observations were recorded vi. Into the other half of it, 10 drops of 16% alpha napthol followed by 40% KOHH were added and left for 10 mins vii. Observations were recorded
- SUGAR FERMENTATION MATERIALS: Inoculating loop, the unknown specimen, test tubes, sterilizing flame, sugars (sucrose, lactose and glucose) METHOD: i. A loop full of the organism was inoculated into 3 test tubes each containing sucrose, lactose and glucose. ii. It was then left for 48 hours iii. After 48 hours, the observations were recoded for each test tube culture
- STARCH HYDROLYSIS MATERIALS: Inoculating loop, unknown specimen, test tube, sterilizing, petri dish containing, dropping pipette. METHOD: i. The inoculating loop was sterilized in the flame. ii. The specimen is streaked across the petri dish. iii. The specimen is left to incubate for 48 hours iv. Iodine is used to flood the medium with a pipette. v. Observations were recorded.
- MOTILITY TEST MATERIALS: Inoculating needle, unknown specimen, test tube, sterilizing flame. METHOD: i. The inoculating needle was sterilized in the flame. ii. Inoculation of specimen by stabbing into the medium with inoculating needle
formed (iii) Glucose Colour change to yellow, no gas formed
A Glucose fermented
- Catalase Bubble formed + Oxygen formed, presence of catalase enzyme
- Oxidase There was no change
DISCUSSION
METHOD OF IDENTIFICATION The unknown organism B was identified by comparing the test results with the established results found in The Microbiology Practical manual. The experiments carried out included catalase test, motility test, citrate test, TSIA, indole tests, MRVP, sugar fermentation, starch hydrolysis and oxidase tests. In the experiment carried out, the catalase test returned positive as opposed to the table it was compared with in which it was negative. The reason for this difference was due to external factors.
MOST SIGNIFICANT TESTS From the test carried out the most significant result were the indole test, methyl red, VP and catalase test which make up the IMVIC test. Proteus vulgaris is a rod-shaped, nitrate-reducing, indole+ and catalase- positive, hydrogen sulfide-producing, Gram-negative bacterium that inhabits the intestinal tracts of humans and animals. It can be found in soil, water, and fecal matter. It is grouped with the Enterobacteriaceae and is an opportunistic pathogen of humans. It is known to cause wound infections and other species of its genera are known to cause urinary tract infections.
Scientific classification Kingdom: Bacteria Phylum: Proteobacteria Class: Gammaproteobacteria Order: Enterobacteriales Family: Enterobacteriaceae Genus: Proteus
Species: P. vulgaris Binomial name Proteus vulgaris (REF Hauser 1885)
Proteus vulgaris is a rod-shaped Gram-negative chemoheterotroph bacterium. The size of individual cells varies from 0.4~0.6μm by 1.2~2.5μm. P. vulgaris possesses peritrichous flagella, making it actively motile. It inhabits the soil, polluted water, raw meat, gastrointestinaltracts of animals, and dust. In humans, Proteus species most frequently cause urinary tract infections, but can also produce severe abscesses; P. mirabilis produces 90 percent of cases, and is encountered in the community, but P. vulgaris is associated with nosocomial infection
