https://www.facebook.com/profile.php?id=61551846626753

KenMartin E-Pro Diagnostic, chidoziekenmartin@gmail. com, Enugu (2025)

19/07/2025

Sulphur Indole Motility (SIM) Test

---

1. Objective

The objective of the SIM test was to determine an organism’s ability to produce hydrogen sulfide (H₂S), indole, and to demonstrate motility.

---

2. Principle

The SIM medium contained ingredients to detect:

Sulfur reduction: Bacteria that produced H₂S reacted with ferrous ammonium sulfate, forming a black precipitate.

Indole production: Bacteria that broke down tryptophan produced indole, which reacted with Kovac’s reagent to produce a red ring.

Motility: Motile organisms spread from the stab line into the semi-solid medium, causing turbidity.

---

3. Materials

SIM agar medium (semi-solid)

Inoculating needle

Kovac’s reagent

Test organism (pure culture)

Incubator (35–37°C)

Test tubes, marker

Bunsen burner, gloves

---

4. Procedure (Microscopic)

(Note: It is a macroscopic test, not microscopic.)

The SIM tube was labeled and a sterile needle was used to stab the medium straight down to about two-thirds depth.

The tube was incubated at 35–37°C for 24–48 hours.

After incubation, 3–5 drops of Kovac’s reagent were added to the surface to test for indole.

The medium was observed for black precipitate (H₂S), red layer (indole), and diffuse growth (motility).

---

5. Result

H₂S production:

Positive: Black precipitate

Negative: No blackening

Indole production:

Positive: Red ring on top after Kovac’s reagent

Negative: No color change

Motility:

Positive: Diffused or fuzzy growth away from the stab line

Negative: Growth restricted to the stab line

---

6. Uses

Used for identifying Enterobacteriaceae members and differentiating Proteus, Salmonella, E. coli, Klebsiella, etc.

Enabled quick assessment of three biochemical traits in one medium.

---

7. Consultation

The results were correlated with other biochemical tests for accurate identification.

Positive H₂S with indole helped identify Proteus vulgaris; non-motile and indole-negative patterns suggested Klebsiella.

Microbiologists consulted findings for diagnosis and treatment planning.

19/07/2025

Stool Routine Examination (Wet Prep)
1. Objective
The objective of the stool routine examination was to analyze a stool sample to detect the presence of intestinal parasites, blood, mucus, pus cells, undigested food particles, and other abnormalities, aiding in the diagnosis of gastrointestinal infections and disorders.

2. Principle
The examination was based on both macroscopic and microscopic evaluation of a stool specimen. The microscopic examination, particularly, relied on direct saline and iodine preparations to detect motile trophozoites, cysts, ova, and larvae of intestinal parasites, as well as other abnormal cells or elements.
________________________________________
3. Materials
The following materials were used for the microscopic stool examination:
• Clean dry container for stool collection
• Glass slides and cover slips
• Normal saline (0.85% NaCl)
• Lugol’s iodine
• Applicator sticks or wooden sticks
• Microscope
• Gloves
• Biohazard disposal container
________________________________________
4. Procedure (Microscopic)
• A small portion of fresh stool was collected using an applicator stick.
• Two separate smears were prepared on glass slides: one with a drop of normal saline and another with a drop of Lugol's iodine.
• The stool was mixed thoroughly with the respective liquids using the stick.
• Each slide was covered with a cover slip, avoiding air bubbles.
• The slides were then examined under a microscope using 10x and 40x objectives.
• Motile trophozoites, cysts, ova, and larvae, as well as RBCs, pus cells, yeast, and fat globules were observed and recorded.
________________________________________
5. Result
The examination results typically reported the presence or absence of:
• Ova or cysts of parasites (e.g., Entamoeba histolytica, Giardia lamblia, Ascaris lumbricoides)
• Pus cells and red blood cells (RBCs)
• Yeast cells or fungal elements
• Undigested food particles
• Fat globules or muscle fibers
• Consistency, color, mucus, and any visible blood in stool (from macroscopic exam)
Example:
Cysts of Giardia lamblia were observed in iodine preparation. Pus cells were moderately present. No RBCs or trophozoites were seen.
________________________________________
6. Uses
The stool routine examination had multiple diagnostic uses, including:
• Identifying intestinal parasitic infections
• Investigating causes of chronic diarrhea or dysentery
• Detecting gastrointestinal bleeding or inflammatory bowel conditions
• Evaluating malabsorption syndromes
• Monitoring treatment efficacy for parasitic infections
________________________________________
7. Consultation
After obtaining the results, a consultation was provided by a medical professional. The findings were interpreted in the context of the patient’s clinical history and symptoms. Based on the results, appropriate treatments such as antiparasitic, antibacterial, or supportive therapies were advised, or further diagnostic tests were recommended if needed.

18/07/2025

♦️Wound Swab Culture♦️
1. Objective
To isolate and identify bacterial or fungal pathogens from a wound infection site and determine their antibiotic susceptibility, guiding appropriate treatment.
________________________________________
2. Principle
A sterile swab is used to collect exudate or tissue from the base of the wound. The sample is cultured on appropriate media under aerobic and/or anaerobic conditions. Grown organisms are identified, and antimicrobial susceptibility testing is performed using standard methods.
________________________________________
3. Materials
• Sterile wound swab with transport medium (e.g., Amies)
• Blood agar, MacConkey agar, Chocolate agar
• Anaerobic media (e.g., CDC anaerobe blood agar, thioglycollate broth)
• Inoculating loop or swab
• Gram staining reagents
• Incubator (aerobic and anaerobic, 35–37°C)
• Mueller-Hinton agar + antibiotic discs
• PPE (gloves, lab coat, mask)
________________________________________
4. Procedure
A. Specimen Collection
1. Clean the wound surface to remove contaminants.
2. Using a sterile swab, collect specimen from the wound base or exudate.
3. Place the swab in transport medium and send to the lab promptly.
B. Culture
1. Inoculate the sample onto:
o Blood agar (detects hemolytic organisms)
o MacConkey agar (detects Gram-negative organisms)
o Anaerobic media if anaerobes are suspected
2. Incubate at 35–37°C:
o 24 hours for aerobes
o 48–72 hours for anaerobes
C. Identification
1. Observe colony morphology and hemolysis.
2. Perform Gram stain from colonies.
3. Confirm identity via biochemical tests or automated systems.
4. Perform antibiotic susceptibility testing (e.g., Kirby-Bauer).
________________________________________
5. Result Interpretation
Organism Typical Culture Finding
Staphylococcus aureus Golden-yellow colonies, Gram-positive cocci
Pseudomonas aeruginosa Green pigment, fruity odor, NLF on MacConkey
Streptococcus pyogenes Beta-hemolytic on Blood agar
Anaerobes Growth only in anaerobic conditions

6. Uses
• Diagnose wound infections, including:
o Post-surgical wounds
o Diabetic foot ulcers
o Burn wound infections
• Guide targeted antimicrobial therapy
• Detect multi-drug resistant organisms (e.g., MRSA, Pseudomonas)
________________________________________
7. Conclusion
Wound swab culture is a critical test for diagnosing and managing wound infections. Proper sample collection and timely processing ensure accurate identification of pathogens and effective treatment decisions.
Credit:
Medical Laboratory Scientists

17/07/2025

Norovirus PCR / Antigen Test
1. Objective
To detect Norovirus in stool or vomitus samples for diagnosis of acute viral gastroenteritis, especially during outbreaks in closed settings (schools, cruise ships, hospitals, etc.).

2. Principle
🔬 A. PCR (RT-PCR)
Detects norovirus RNA using reverse transcription polymerase chain reaction (RT-PCR). Highly sensitive and specific, capable of detecting even low viral loads and differentiating between genogroups (GI, GII).
🔬 B. Antigen Test (Rapid Immunoassay)
Detects norovirus capsid antigens using lateral flow immunochromatographic assays or ELISA. Quick and convenient but less sensitive than PCR.
________________________________________
3. Materials
For PCR:
• Stool sample (fresh or frozen)
• RNA extraction kit
• RT-PCR reagents and primers for Norovirus GI/GII
• Thermocycler or real-time PCR system
• Nuclease-free water, tubes, and PPE
For Antigen Test:
• Stool sample
• Norovirus antigen test kit (lateral flow/ELISA)
• Sample buffer
• Pipette/dropper
• Timer and PPE
________________________________________
4. Procedure
🧪 RT-PCR:
1. Extract viral RNA from stool sample.
2. Prepare master mix with RT and Norovirus primers/probes.
3. Load samples into PCR tubes or wells.
4. Run RT-PCR program.
5. Interpret amplification curves and Ct values.
🧪 Antigen Test (Lateral Flow):
1. Mix stool sample with buffer.
2. Add drops to sample well of test device.
3. Wait 10–15 minutes.
4. Observe for control (C) and test (T) lines.
________________________________________
5. Result Interpretation
Test Result Interpretation
RT-PCR Ct < 40 Norovirus detected
RT-PCR No Ct Not detected
Antigen C + T lines Positive
Antigen C line only Negative
Antigen No C line Invalid
________________________________________
6. Uses
• Diagnose viral gastroenteritis caused by norovirus
• Monitor outbreaks in healthcare and institutional settings
• Guide infection control measures
• Support public health surveillance
________________________________________
7. Conclusion
RT-PCR is the gold standard for detecting norovirus, offering high sensitivity and specificity. Antigen tests are faster and easier but may miss low viral loads. Both play a critical role in managing gastroenteritis outbreaks.

17/07/2025

Erythrocyte Sedimentation Rate (ESR) Test
1. Objective
The objective of the ESR test was to measure the rate at which red blood cells (RBCs) settled at the bottom of a vertical tube in a given time period (usually 1 hour), to assess the presence of inflammation or infection in the body.

2. Principle
The ESR test was based on the principle that inflammatory processes caused red blood cells to clump together (rouleaux formation), increasing their sedimentation rate.
• The greater the inflammation, the faster the RBCs settled.
• The distance (in mm) that RBCs fell in a vertical tube over 1 hour indicated the ESR value.
________________________________________
3. Materials
• Fresh anticoagulated blood (with EDTA or sodium citrate)
• Westergren ESR tube (200 mm long)
• Westergren pipette stand or ESR rack
• Timer or stopwatch
• Gloves
• Syringe or pipette
________________________________________
4. Procedure (Macroscopic)
1. 1 part of 3.8% sodium citrate was mixed with 4 parts of blood.
2. The mixture was drawn into a Westergren tube up to the 0 mark.
3. The tube was placed vertically in an ESR rack.
4. After exactly 1 hour, the level of plasma above the RBC column was recorded in millimeters.
________________________________________
5. Result
• ESR was recorded in mm/hr.
• Normal Range:
o Males: 0–15 mm/hr
o Females: 0–20 mm/hr
o Children: 0–10 mm/hr
o Elderly: Slightly higher
• Elevated ESR indicated inflammation, infection, autoimmune disorders, or malignancy.
________________________________________
6. Uses
• Used as a non-specific marker of inflammation.
• Helped monitor disease progression or treatment effectiveness in conditions like:
o Rheumatoid arthritis
o Tuberculosis
o Temporal arteritis
o Chronic infections
• Also used in diagnosing autoimmune diseases and certain cancers.
________________________________________
7. Consultation
• ESR results were interpreted alongside clinical symptoms and other laboratory findings.
• A high ESR alone did not confirm a diagnosis but prompted further investigations.
• Physicians used ESR to monitor chronic conditions and determine disease activity.

16/07/2025

Sulphur Indole Motility (SIM) Test
---

1. Objective

The objective of the SIM test was to determine three bacterial characteristics in a single test:

Sulfide production (H₂S)

Indole production

Motility

---

2. Principle

The SIM medium contained:

Peptone and sodium thiosulfate for detecting hydrogen sulfide (H₂S) production.

Tryptophan, which some bacteria degraded to indole.

Semi-solid agar, allowing detection of motility.

H₂S combined with iron salts in the medium to form a black precipitate.

Indole, if produced, reacted with Kovac’s reagent to form a red layer.

Motility was indicated by diffuse growth radiating from the stab line.

---

3. Materials

SIM agar medium (in test tubes)

Bacterial culture (pure colony)

Inoculating needle

Kovac’s reagent

Incubator (35–37°C)

Marker pen

Gloves, Bunsen burner

---

4. Procedure (Microscopic)

(Note: The SIM test is macroscopic, not microscopic, but here is the correct format)

A sterile inoculating needle was used to pick a small amount of bacterial culture.

The needle was stabbed straight down into the center of the SIM medium tube.

The tube was incubated at 35–37°C for 24–48 hours.

After incubation, Kovac’s reagent (5 drops) was added to detect indole.

Results were interpreted for black precipitate (H₂S), red color (indole), and diffusion from stab line (motility).

---

5. Result

Sulfur:

Positive: Black precipitate

Negative: No blackening

Indole:

Positive: Red ring on top after Kovac’s reagent

Negative: No color change

Motility:

Positive: Diffuse, fuzzy growth away from stab line

Negative: Growth confined to stab line

---

6. Uses

Differentiated Enterobacteriaceae family members

Identified motile and indole-producing bacteria such as Escherichia coli, Proteus vulgaris, and others

Helped in rapid screening of multiple bacterial traits in a single tube

---

7. Consultation

Results were confirmed alongside other biochemical tests for accurate identification.

Positive H₂S and indole production were indicative of Proteus species.

Motility findings helped distinguish non-motile bacteria like Klebsiella from motile ones like E. coli.

Clinical interpretation was done in consultation with microbiologists for treatment planning.

15/07/2025

Gram Staining
1. Objective
The objective of the Gram staining test was to differentiate bacteria into two major groups: Gram-positive and Gram-negative, based on the composition of their cell walls.
________________________________________
2. Principle
Gram staining was based on the ability of bacterial cell walls to retain the crystal violet dye during solvent treatment.
• Gram-positive bacteria retained the crystal violet-iodine complex and appeared purple due to their thick peptidoglycan layer.
• Gram-negative bacteria, with a thinner peptidoglycan layer and outer membrane, were decolorized and took up the safranin counterstain, appearing pink/red.
________________________________________
3. Materials
• Glass slides
• Bacterial culture (smear)
• Crystal violet
• Gram’s iodine
• Decolorizer (95% alcohol or acetone)
• Safranin
• Distilled water
• Bunsen burner
• Staining rack
• Microscope
• Immersion oil
________________________________________
4. Procedure (Microscopic)
1. A bacterial smear was prepared on a clean glass slide and heat-fixed.
2. The slide was flooded with crystal violet for 1 minute, then rinsed.
3. Gram’s iodine was applied for 1 minute as a mordant, then rinsed.
4. The slide was washed with alcohol (decolorizer) for 10–30 seconds, then rinsed.
5. Safranin was added for 1 minute to counterstain, then rinsed.
6. The slide was air-dried and examined under the microscope using oil immersion (100x objective).
________________________________________
5. Result
• Gram-positive bacteria appeared purple or blue-violet.
• Gram-negative bacteria appeared pink or red.
• Mixed reactions indicated gram-variable or improperly performed stain.
________________________________________
6. Uses
• It was used as a primary staining technique in microbiology.
• Helped classify bacteria and guided antibiotic therapy decisions.
• Used in clinical diagnostics to quickly identify bacterial infections.
• Essential in identifying morphology and arrangement (cocci, bacilli, chains, clusters, etc.).
________________________________________
7. Consultation
• Gram stain results were reported with bacterial morphology to clinicians.
• Helped initiate empirical treatment before culture results.
• Interpretation was done by trained microbiologists using a microscope.

13/07/2025

Identification of Microorganisms Based on Colony Morphology – A Core Microbiological Skill

The attached image shows 8 microbial isolates cultured on an agar plate. Each organism was preliminarily identified based on the distinct morphological characteristics of its colonies, as follows:

1. Escherichia coli

Colonies are smooth, round, with a glossy surface and pale coloration (often pinkish or off-white). Their regular shape and moist appearance are key identifiers.

2. Stenotrophomonas maltophilia

Colonies appear sticky or slightly mucoid with a distinctive pale yellow hue. The pigmentation and surface texture assist in preliminary identification.

3. Staphylococcus aureus

Colonies are golden-yellow due to carotenoid pigment production. They are smooth, convex, and shiny, making them easily distinguishable.

4. Enterococcus faecalis

Colonies are small, greyish, dull, and often lack pigmentation. Their dry, non-glossy texture distinguishes them from other cocci.

5. Candida albicans

A yeast species forming thick, creamy-white colonies that are raised and soft in texture, resembling curd or milk cream. Their distinct morphology is indicative of fungal growth.

6. Klebsiella pneumoniae

Colonies are large, mucoid, and glistening due to the organism’s prominent capsule. The color is typically bluish or grayish, and the sticky appearance is diagnostic.

7. Staphylococcus epidermidis

Colonies are smooth, white, and slightly shiny. They are generally smaller and less pigmented than S. aureus, and appear more uniform.

8. Pseudomonas aeruginosa

Colonies exhibit a characteristic blue-green pigmentation due to pyocyanin production. They may also emit a distinctive odor and have irregular edges with a flat surface.

Note:
While colony morphology provides valuable initial clues, definitive identification requires:

Biochemical testing

Gram staining

Advanced molecular methods such as PCR or MALDI-TOFDr.

12/07/2025

Procalcitonin Test
1. Objective
The objective of the test was to measure the level of procalcitonin in the patient’s blood, aiding in the diagnosis of bacterial infections and sepsis, and helping to distinguish between bacterial and viral infections.
________________________________________
2. Principle
Procalcitonin is a precursor of the hormone calcitonin, which increases significantly in response to bacterial endotoxins but not in viral infections or inflammatory conditions. The test was based on immunoassay techniques (e.g., ELISA, immunofluorescence, or chemiluminescence) to detect and quantify serum procalcitonin levels.
________________________________________
3. Materials
• Serum or plasma sample (collected in plain or lithium heparin tube)
• Procalcitonin reagent kit (ELISA or automated analyzer-based)
• Microplate reader or immunoassay analyzer
• Micropipettes, test tubes, controls, wash buffers (for ELISA)
________________________________________
4. Procedure (ELISA Method – simplified overview)
1. Blood was collected, allowed to clot, and serum was separated.
2. Standards, controls, and patient samples were added to pre-coated wells with anti-procalcitonin antibodies.
3. After incubation, enzyme-conjugate was added.
4. A substrate was introduced, and a color change indicated the presence of procalcitonin.
5. The absorbance was read with a microplate reader and compared to a standard curve.
________________________________________
5. Result
• Normal Range: 2.0 High probability of severe sepsis/septic shock
________________________________________
6. Uses
• Helped differentiate bacterial vs viral infections
• Assisted in early sepsis diagnosis
• Monitored response to antibiotic therapy
• Reduced unnecessary antibiotic use
________________________________________
7. Conclusion
The Procalcitonin test proved to be a valuable biomarker for identifying bacterial infections and sepsis, offering higher specificity than other inflammatory markers such as CRP

11/07/2025

Stool Culture test
1. Objective
To isolate and identify enteric pathogens (bacteria) in a stool sample, such as:
• Salmonella spp.
• Shigella spp.
• Vibrio cholerae
• Campylobacter spp.
• E. coli (pathogenic strains like EHEC, ETEC, EIEC)

2. Principle
Stool samples are inoculated onto selective and differential media that promote growth of enteric pathogens while suppressing normal flora. Suspected colonies are identified via biochemical tests, serotyping, and antibiotic sensitivity is performed when appropriate.
________________________________________
3. Materials
• Fresh stool specimen (in sterile container)
• Selective media:
o XLD (Xylose Lysine Deoxycholate) agar
o MacConkey agar
o Salmonella-Shigella (SS) agar
o TCBS (for Vibrio)
o Campylobacter selective agar
• Inoculating loop or swab
• Incubator (aerobic & microaerophilic, 35–42°C)
• Biochemical identification kits (e.g., TSI, SIM, Citrate)
• Antisera for serotyping
• Mueller-Hinton agar for antibiotic testing
________________________________________
4. Procedure
1. Collect fresh stool (or re**al swab if needed).
2. Use a sterile loop to streak stool onto selective media plates.
3. Incubate:
o Most plates: 35–37°C for 18–24 hours
o Campylobacter: 42°C, microaerophilic for 48 hours
4. Examine colonies for morphology and color:
o Salmonella: colorless on MacConkey, black center on XLD/SS
o Shigella: colorless on MacConkey and XLD
o Vibrio: yellow colonies on TCBS
5. Perform Gram stain and biochemical tests.
6. Confirm by serotyping and report antibiotic sensitivity.
________________________________________
5. Result Interpretation
Media Organism Appearance
MacConkey agar LF = pink (E. coli); NLF = colorless (Shigella, Salmonella)
XLD agar Yellow = E. coli; Red with black = Salmonella
SS agar Colorless or black-centered colonies = Shigella, Salmonella
TCBS Yellow = Vibrio cholerae
________________________________________
6. Uses
• Diagnose bacterial gastroenteritis
• Detect outbreaks of foodborne illness
• Guide targeted antibiotic treatment
• Monitor public health trends
________________________________________
7. Conclusion
Stool culture is essential for identifying enteric pathogens, especially during outbreaks or in severe diarrheal cases. Proper sample handling, use of selective media, and interpretation based on morphology and biochemistry ensure reliable diagnosis.

03/07/2025

F***l Occult Blood Test (FOBT)
________________________________________
1. Objective
The objective of this test was to detect hidden (occult) blood in the stool, which could indicate gastrointestinal bleeding, even when not visible to the naked eye.
________________________________________
2. Principle
The test relied on the peroxidase-like activity of hemoglobin in blood. Hemoglobin catalyzed the oxidation of a chromogen (usually guaiac or tetramethylbenzidine) in the presence of hydrogen peroxide, producing a blue color if blood was present.
________________________________________
3. Materials
• Stool sample (in clean container)
• Guaiac-impregnated test card or immunochemical test kit
• Developer reagent (e.g., hydrogen peroxide)
• Applicator sticks
• Gloves
________________________________________
4. Procedure (Guaiac Method)
1. A small smear of stool was applied to the test card's sample areas.
2. The card was closed and allowed to dry.
3. Developer reagent was applied to the reverse side of the test areas.
4. The appearance of a blue color within 30–60 seconds indicated a positive result.
________________________________________
5. Result
• Positive test: Blue coloration = occult blood present
• Negative test: No color change = occult blood not detected
Example Interpretation:
• Test Result: Positive
• Clinical Correlation: Suggestive of colore**al bleeding, ulcer, or polyps
________________________________________
6. Uses
• Screened for colore**al cancer and polyps
• Helped detect GI bleeding from ulcers or gastritis
• Part of routine annual screening for individuals over 50 years
________________________________________
7. Conclusion
The F***l Occult Blood Test was a non-invasive, cost-effective screening tool used to detect hidden gastrointestinal bleeding, which may indicate serious underlying conditions such as cancer or peptic ulcers.

29/06/2025

Three-Part Rule.

KenMartin E-Pro Diagnostic

19/07/2025

19/07/2025

18/07/2025

17/07/2025

17/07/2025

16/07/2025

15/07/2025

13/07/2025

12/07/2025

11/07/2025

03/07/2025

29/06/2025

Address

Website

Alerts

Shortcuts

Share

Category