MMIC BLOG 1 - Case 6

Preliminary Information

Name: Ong Fei Fei
Sex: Female
Age: 37
Clinical Diagnosis: Urinary Tract Infection (UTI)
Symptoms: Fever, pain during urination, virginal discharge
Anitbiotic Treatment: none
Specimen: Vaginal discharge


Introduction

[UTI]

• More common in female than male
• Infection occurs less frequently in men because the urethra is much longer and the distance between the anus and urethral meatus is greater than in women
• Prostatic secretions also confer a degree of antibacterial activity
• A single episode of UTI in women is usually uncomplicated
• UTI infection is limited to the bladder - the responsible organisms are usually gram negative coliforms
• Ascending infection from the bladder can cause acute pyelonephritis which typically presents with loin pain, fever and chills, costovertebral angle tenderness, nausea and vomiting
• A woman with UTI symptoms without significant bacteriuria finding on culture = acute uretheral syndrome (in 30% cases; 70% bacterial infections)
• Patients with acute uretheral syndrome can be either with pyuria on urinalysis (70%) or without (30%)
• Those with pyuria have true microbial infection usually with chlamydia; those without pyuria have no known microbial cause and the dysuria (a burning sensation in the urethra during voiding) and frequency may be related to irritation from mechanical trauma
• Mostly caused by Commensal colonic gram-negative aerobic bacteria (> 75%)E.g. E. coli strains (with specific attachment factors for transitional epithelium of the bladder and ureters), other enterobacteria, especially Klebsiella, Proteus mirabilis, and Pseudomonas aeruginosa.
• Enterococci (group D streptococci) and coagulase-negative staphylococci (eg, Staphylococcus saprophyticus) are the most frequently implicated gram-positive organisms.
• Infection Localization - Vaginitis is often distinguished by the presence of vaginal discharge, vaginal odor, and dyspareunia

[Vaginal Discharge]

• It is a secretion produced from glands in the vaginal and the cervical lining
• All women have a little discharge starting approximately a year before puberty and ending after the menopause
• A normal physiological discharge is usually clear, creamy or very slightly yellow
• Abnormalcy when there is suddenly a great amount of discharge or the color is brownish, reddish or greenish or it becomes smelly.
• Pathogens implicated are bacterial, fungal and protozoan
• May be associated with Sexually Transmitted Disease (STDs); due to hypoestrogenism
  
  

Etiology

Trichomonas Vaginalis

• Transmission: STD
• Symptoms: Frothy green/yellow discharge, pruritus, urinary symptoms. May be asymptomatic (50%)
• Protozoa found only in tropozoite stage, with 4 flagella
• May be seen in urine
• Offensive odour
• Vagina may be inflamed (Complain of Vaginal/Vulval pruritis)
• May have cervical erosions
  

Candida Albicans

• A type of fungal (yeast) infection
• Transmission: Increased with pregnancy, Diabetes Mellitus & antibiotics.
• Symptoms: Discharge is white, resembles milk curds; Severe itching, dysuria, dyspareunia.

Bacterial Vaginosis (anaerobic/non-specific)

(Rarely presented with dysuria or dyspareunia)

1. Gardnerella vaginalis
Transmission: unknown; may be STD
Symptoms: Thin, watery, yellow-gray discharge with "fishy" odor

2. Mobiluncus species

3. Gonorrhoea
Transmission: STD (More easily transmitted from an infected man to womon ~90%)
Symptoms: Purulent vaginal discharge, dysuria, urinary frequency, inflammation, vulvar swelling and the cervix may be eroded. Most women are asymptomatic.

4. Chlamydia trachomatis (C. trachomatis, C. psittaci, C. pneumoniae)
Transmission: commonly STD
Symptoms (mild): May have thin/purulent discharge, urinary burning and frequency, lower abdominal pain and friable cervix. Women usually asymptomatic.


Possible Interpretation
Vaginal Discharge - suggests Vaginitis or urethritis (e.g. Sexually transmitted Disease (STD), candidiasis) due to hypoestrogenism: e.g. T. vaginalis or N. gonorrhoeae.


Investigation required

• Urinalysis - for screening; inexpensive, easy to perform
• Urine culture - for accurate diagnosis of infection to determine complications, such as antimicrobial susceptibility of infecting bacteria
• Vaginal and urethral discharge - wet-mount preparation to detect Trichomonas vaginalis and Candida species
• Gramstaining - detect Neisseria gonorrhoeae

References:

http://www.escriber.com/ > TrendsInUGSH > Features
http://www.cfps.org.sg/ > sfp > 23 > 232> articles > e232136.html
http://cks.library.nhs.uk/ > uti_lower_women > in_depth > goals_and_outcome_measures
http://www.merck.com/ > mmpe > sec17 > ch231 > ch231b.html
http://www.aafp.org/ > afp > 20020415 > 1589.pdf

Posted by: Pei Shan, TG02

MMIC PBL - Case 3

Specimen 3:
Preliminary Information:
Patient: Maisy Hong (67 years)
Sample: Urine
Symptoms: Fever, chills, bladder distension; on indwelling catheter
Bladder distension: Inability to urinate. May be due to obstruction.
Indwelling catheter: prevent catheter from being pulled out of the bladder
Diagnosis: Urinary Track Infection

- Women are more prone to UTI as the urethra is much shorter and closer to the anus than in males. Also, they lack the bacteriostatic properties of prostatic secretions.
- Use of urinary catheters (foreign body) in elderly may result in an increased risk of urinary tract infection.

Possible causative agents:

1. Bacteria: Causes up to 85% of all UTI cases.
(a) Escherichia coli: Most common causative agent of UTI, typically from bowels (colon).

(b) Enterococcus Species: Originate from colon.
E. faecalis

(c) Klebsiella Species: Opportunistic pathogens that causes nosocomial infections
K. pneumoniae

(d) Enterobacter Species: Opportunistic pathogen; Present in large intestine but also present in soil and water.
E. aerogenes
E. cloacae
E. taylorae

(e) Proteus Species: Have urease activity that raises urinary pH. Causes stone formation.
P. mirabilis

(f) Pseudomonas Species: Causes UTI primarily in patients with lowered host defences
P. aeruginosa

2. Fungi: Account for 40% of nosocomial UTI cases.

(a) Candida Species: may cause UTI in diabetic patients
C. albicans - causes vaginitis and chronic mucocutaneous candidiasis


As patient has a catheter, it is likely associated with contributing to UTI.
In this case, most incidences are caused by bacterial infection/colonization of the catheter, hence bacteria are suspected to be the cause.
Fungal stain may be used to rule out fungal infection in this case.

To narrow down type of bacteria, a gram stain should be done, to determine gram stain as well as morphology or bacteria:
Gram Stain:
Negative (pink): Escherichia coli (rod), Proteus Species (rod), Enterobacter Species (bacilli), Klebsiella Species (bacilli), Pseudomonas Species (bacilli).
Positive (purple): Enterococcus Species (cocci)

Gram negative strains are the most common causes; hence further biochemical test, urine cultures and antibiotic susceptibility must be employed to narrow down causative agent.

Most probable agents: according to incidence seen in UTI patients
Escherichia coli – 53-72%
Klebsiella pneumoniae – 6-12%
Proteus mirabilis – 4-6%
Enterococcus faecalis – 2-12%

References:
calder.med.miami.edu > pointis > indwelling.html
wrongdiagnosis.com > medical > bladder_distension.htm
kcom.edu > faculty > chamberlain > Website > lectures > lecture > uti.htm

Cheers,
Debra (TGo2)

MMIC - case 4

Name: Tong Wei Hong
Age: 68 yrs old
Sex: Male

Complaints: Fever, chills, excessive phlegm, breathing problems
Diagnosis: Bronchitis
Specimen: Sputum

Bronchitis is a respiratory disease in which the mucous membrane in the lungs' bronchial passages becomes inflamed. As the irritated membrane swells and grows thicker, it narrows or shuts off the tiny airways in the lungs, resulting in coughing spells accompanied by thick phlegm and breathlessness. There are two main types of bronchitis: acute and chronic.

- Several viruses cause bronchitis, including influenza A and B.

- A number of bacteria are known to cause bronchitis, such as Mycoplasma pneumoniae.

- Bronchitis also can occur when you inhale irritating fumes or dusts. Chemical solvents and smoke, including tobacco smoke, have been linked to acute bronchitis.

- People at increased risk both of getting bronchitis and of having more severe symptoms include the elderly, those with weakened immune systems, smokers, and anyone with repeated exposure to lung irritants.

Microorganisms commonly isolated from sputum include:
- Streptococcus pneumonia,
- Haemophilus influenzae
- Staphylococcus aureus
- Legionella pneumophila
- Mycoplasma pneumonia
- Klebsiella pneumoniae
- Pseudomonas aeruginosa
- Bordetella pertussis
- Escherichia coli

Cultures and tests are done on the sputum to help identify the bacteria that are causing an infection in the lungs or the airways (bronchi).
· Bacterial culture - gram stain or acid fast stain of the sputum done at the same time can help make the diagnosis.

· Fungal culture - The sputum sample is spread on special culture plates that will encourage the growth of mold and yeast. Different biochemical tests and stains are used to identify molds and yeast. Cultures for fungi may take several weeks.

· Viral culture - sputum is mixed with commercially-prepared animal cells in a test tube. Characteristic changes to the cells caused by the growing virus help identify the virus.

References
bronchitis>causes/">http://www.emedicinehealth.com>bronchitis>causes
http://www.lifesteps.com>Home > Encyclopedia > Encyclopedia Index S

Eunice
TG02

dPBL MMIC:cheng hong (enterocolitis)

Name: Kuan Siew Yan / 29yrs/ Female

Symptom(s):Diarrhoea
Diagnosis: Enterocolitis


What is Enterocolitis?
Cause by organisms that invade the epithelial and the subepithelial tissue of the small and large intestine thus causing inflammation and diarrhea.

Possible Causative Agents
1.Salmonella species
2.Shigella species
3.Campylobacter jejuni
4.Escherichia coli O157

1. Salmonella
§ Characteristics: Rigid, thick walled cell, Gram negative, Facultative straight rods

§ Species: S.typhi, Salmonella choleraeuis, Salmonella enteritidis


§ Pathogenesis: Manifest as Enterocolitis (penetrates through mucosal cells into the lamina propria; need at least 100000 organisms to cause infection). Typhoid/enteric fevers or Septicemia.

§ Biochemical features: Non lactose fermenting colonies on MacConkey/ EMB agar
: Alkaline slant/ acidic butt, gas and H2S in butt in TSI
: Lysine, Aginine, Ornithine positive
: indole neg, methyl red pos, Voges-Proskauer neg, citrate neg


2. Shigella species
§ Charateristics: Rigid, thick walled cell, Gram negative, Facultative straight rods, non-motile

Species: 4 different genus groups (A,B,C,D)


Pathogenesis: virulent (only need 100 organism to cause the disease), transmitted through fecal-oral route, normally have bloody diarrhea

Biochemical features: non-lactose fermenting, no gas production from fermenting glucose, no H2S production, alkaline slant and acidic butt on TSI, indole neg, methyl red pos, vogues proskauer neg, citrate neg, lysine arginine ornithine neg

Other features: a methylene blue stain will differentiate if it is an invasive or toxin producing bacteria (neutrophils will show that it is an invasive infection; like Shigella, Salmonella, Campylobacter


3. Campylobacter jejuni
§ Characteristics: Rigid, thick walled cell, Gram negative, Facultative curved rods (S shape)

§ Species: C. jejuni, C. intestinalis


§ Pathogenesis: Transmitted through fecal oral route or food/water contaminated with Campylobacter, causes entrocolitis

§ Biochemical features: culture on blood plate containing antibiotics (vancomycin, trimethoprim, cephalothin, polymyxin, amphotericin B) and incubate at 42oC at 5%oxygen and 10% carbon dioxide, no H2S production on TSI, hippurate hydrolysis test pos for C. jejuni, susceptible to nalidixic


§ Others: hanging drop shows motility of Campylobacter


4. Escherichia coli O157
Characteristics: Rigid, thick walled cell, Gram negative, Facultative straight rods

Pathogenesis: Enterohemorrhagic infection due to ingesting undercookedmeat, the organism cause the disease by using its features (pili, capsule, endotoxin, 3 exotoxins)-results in watery/ bloody diarrhea


Biochemical features: Can be either lactose fermenting/ non lactose fermenting, appears green on EBM agar, produces indole from tryptophan, decarboxylates lysine, motile, O157:H7 does not ferment sorbitol, acidic slant acidic butt produces gas abd no H2S production

References from:Review of Medical Microbiology and Immunology(9th edition). WARREN LEVINSON

:Color Atlas of Medical Bacteriology. ASM PRESS

Cheng Hong

MMIC

Name: Khong Fay Seah
Age: 27 yrs old
Sex: Female

Complaints: Fever, chills, dysuria (painful urination)
Diagnosis: UTI
Specimen: Urine

Test ordered (Main Lab): Urine FEME (microscopy, dipstick)

Procedure:

Step 1:
A drop of uncentrifuged urine placed into a KOVA chamber, and examined with restricted light intensity under the high-dry objective of an ordinary clinical microscope can reveal leukocytes, epithelial cells, and bacteria.

Finding 105 organisms per millililiter can conclude UTI.
Results:
Normal hematocrit/HB
Elevated WBC (>18,000/uL)
Innumerable white blood cells
A few RBC
Numerous bacteria

Step2:
Positive Urine dipstick nitirite suggest strongly bacteria growth in the urine tract.

Step 3:
A gram-stained smear of uncentrifuged urine that shows gram-negative rods is diagnostic of UTI

Step 4: in the micro lab

· Culture urine using a bacteriologic loop calibrated to deliver 0.01 or 0.00mL to agar plates.
· Aerobic culture ( maconkey and blood agar plates) & incubated overnight @ 37 degree.

In active pyelonephritis, the number of bacteria in urine collected by uretheral catheter is relatively lo.

While accumulating in the bladder, bacteria multiply rapidly and soon reach >105/mL (not contamination). The presence of more than 105/mL of the same type of bacteria per milliliter, establish a diagnosis of active infection. E.coli might be causing bacteria.

If the growth of different types of bacteria fewer than 104/mL, suggest that organisms come from normal flora or contaminants.

This female patient with acute dysuria and UTI will have 102/mL-103/mL.

If the cultures are negative but clinical signs of UTI are present, ureteral obstruction, tuberculosis can be considered.

E.coli cause 80-90% of acute bacterial lower tract infection in young women. The patient with acute cystitis has negative urine cultures for bacteria. Other possible causing bacteria: Staphylococcus, Neisseria Gonorrhoeae, Klebsiella, Enterobacter.

If such infection is caused by E.coli, identification and susceptibility testing of bacteria are not necessary.

elaine

M.mic- Case on WFH

Case: Surgical wound infection
Specimen: Wound swab

There are 2 main types of culture for wound infection. For external wounds (on the surface of the skin), swabs are sent in dry tube and stuart transport medium. The dry swab is used for gram staining to prelimarily identify organisms present on the wound. We normally look out for gram positive or negative organisms, bacilli or cocci. Afterwhich, the swab sent in stuart transport medium is used for culturing on blood agar (BA), macconkey agar (MAC) and cooked meat agar (CM).

BA is used for general growth of organisms and identifying streptococcus strains based on the hemolytic activities (alpha, beta or gamma hemolysis).

MAC is used as an inhibitory and differential medium used to distinguish lactose-fermenting enteric gram-negative bacilli from nonfermenters.

CM is used for isolation of Clostridium and to evaluate proteolysis.


For internal wounds (below the skin surface area), swabs are sent in dry tube, PRAS transport medium and stuart transport medium. The procedures is the same as above for the dry and stuart swabs. For the PRAS swab, we use it to culture on another BA for incubation in CO2 and ANO2

Since a dry swab will be provided, the external culture will be done.

The procedure:

1. Culture on blood agar
2. Culture on Macconkey agar
3. Culture on cooked meat agar
4. Do a gram stain

Gram stain is done after plating because it will contaminate the swab. (the slide is not sterile)

The most common causative organisms isolated for wound infection are:

1. Styphylococcus aureus.
2.Streptococcus pyogenes
3.Clostridium
4. Pseudomonas
5. Enterococcus
6. Proteus mirabilis
7. Enterobacteriaceae


References

Lehmann (1998) Clinical Bacteriology. Saunders Manual of Clinical Laboratory science pages 589 to 667. WB Saunders, Philadelphia

SOP of attachment company.

Elaine"reverse camp test"

hey everyone,

W.R.T last post, I found a case study online about the last post on Acranobacterium hemolyticum

http://www.biomedcentral.com/1471-2334/5/68

If you are free, please visit this website. It show clearly the symptoms and the stages of how a Medical Technologist will do if he/she suspect something.

To lizze, arcanobacterium hemolyticum is quite a difficult to culture out because it need a strictly anaerobe environmemt. If the colonies are too small, B-hemolytic ability is also difficult to observe. The med tech will normally re-isolate the microorganism on a new sheep blood plate because the arcanobacteria will not survive once it is out in the open-air.

This above pic(from the same website) show a clear reaction. It is quite difficult to get this. I don't even get to see a clear one like this.

Elaine