Medical Microbiology- PBL 1 ( second blog)

Case study 1
List of microbes: Staphylococcus aureus, Staphylococcus saprophyticus, Enterococcus faecalis. Escherichia coli, Enterobacter, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Chlamydia trachomatis.

A gram stain will be done first for the suspected bacteria that can cause UTI, before proceeding to any laboratory investigation.

Gram positive bacteria: Staphylococcus aureus, Staphylococcus saprophyticus, Enterococcus faecalis.Gram negative bacteria: Escherichia coli, Enterobacter, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Chlamydia trachomatis.

Biochemical and Culture Testing

Possible Organisms	Staphylococcus aureus	Staphylococcus saprophyticus	Enterococcus faecalis
Gram Stain :positive	cocci(clusters)	cocci(clusters)	cocci(chains)
Culture on Sheep blood agar	haemolytic, yellow colonies	non-haemolytic white colonies	gamma non-haemolytic white colonies( but can show weak alpha haemolysis)
Catalase test	positive	positive	negative
Coagulase test	positive	negative	nil

Possible Organisms	Escherichia coli	Enterobacter sp	Pseudomonas aeruginosa	Klebsiella pneumoniae	Proteus mirabilis
Gram Stain: negative	bacilli	bacilli	bacilli	bacilli	bacilli
Culture on Mac Conkey	pink lactose fermenting colonies	very weak lactose fermenters	non-lactose fermenting colonies producing blue-green pigments	pink lactose fermenting colonies	non-lactose fermenting colonies
Culture on eosin methylene blue (EMB)	metallic green sheen with dark colonies	brown-centered with pale blue colonies	colorless colonies indicating no lactose fermentation and acid production	brown dark-centered colonies indicating lactose fermentation and acid production	colorless colonies indicating no lactose fermentation and acid production
oxidase	negative	negative	positive	negative	negative
*Triple sugar iron (TSI)	acidic slant/acidic deep	alkaline slant/acidic deep	No change	alkaline slant/acidic deep	alkaline slant with black precipitate

acidic slant/acidic deep: ferment lactose and glucose
alkaline slant/acidic deep : ferment glucose only
No change: no carbohydrate fermentation
Black precipitate: H2S production

If oxidase test is negative, proceed to IMViC biochemical test

IMViC	Escherichia coli	Enterobacter sp	Klebsiella pneumoniae	Proteus mirabilis
Indole	+	-	-	-
Methyl red	+	-	-	+
Voges proskauer	-	+	+	-
Citrate test	-	+	+	+
Urease	-	-	-	+

Antibiotic Susceptibility test
5 antibiotics: Gentamycin, Ceftadizime,Cefuroxime, Ampicillin and Ciprofloxacin. Varying zone diameter size can be observed for both the gram positive and negative bacteria.

If Chlamydia trachomatis is highly suspected, as it is a common STD that can cause UTI, some portion of the urine sample can be send for DNA based analysis method such as polymerase chain reaction(PCR).

Case study 2 Besides Salmonella, there are also several other possible microorganisms that could lead to enterocolitis or cause the diarrhea in the patient. Here are the other possibilities:
1. Enterotoxigenic Escherichia coli
2. Campylobacter jejuni
3. Clostridium difficileShigella: S. dysenteriae, S. flexneri, S. boydii, and S. sonnei

Type of microbe	Microscopy test	Biochemical Test	Serology test	Culture
Salmonella	Gram Stain: Gram negative bacilli	TSI: alkaline slant/acid butt with H2S production Indole: Negative Methyl-red: Positive Voges-Proskauer: Negative Citrate: Positive	Slide agglutination test: serotyping using O, H and Vi antigens Tube agglutination test: detect agglutinating Ab to O & H Ag in patient’s serum	MacConkey agar: Observe plate for non-lactose fermenting (clear) colonies Hektoen agar: Observe plate for clear or green colonies and colonies with black centers (H2S production) Salmonella-Shigella agar: Observe plate for clear colonies and colonies with black centers (H2S production) XLD Agar: Observe plate for red colonies and colonies with black centers (H2S production)
Shigella	Gram Stain: Gram negative bacilli	TSI: Alkaline slant/acid butt but no H2S production Indole: Negative Methyl-red: Positive Voges-Proskauer: Negative Citrate: Negative	Slide agglutination test	MacConkey agar: Observe plate for non-lactose fermenting (clear) colonies Salmonella-Shigella agar: Observe plate for clear colonies and colonies WITHOUT black centers (no H2S production) Hektoen agar: Observe plate for clear or green colonies and colonies WITHOUT black centers (no H2S production)
Enterotoxigenic E.Coli	Gram Stain: Gram negative bacilli	TSI: Alkaline slant/acid butt with gas but not H2S production Indole: Positive Methyl-red: Positive Voges-Proskauer: Negative Citrate: Negative	Serotyping using O & H Ag	MacConkey agar: Observe plate for red/pink colonies (lactose-fermenting colonies) EMB agar: Observe plate for greenish metallic sheen
Campylobacter jejuni	Gram Stain: Gram negative bacilli that appear either comma or S- shaped	TSI: Alkaline slant/deep Oxidase: Positive	nil	Selective “CAMP” agar at 42ºC in microaerophilic environment (grow at 5% oxygen + 10% carbon dioxide)
Clostridium difficile	Gram Stain: Gram positive bacilli	nil	nil	Blood agar at human body temperatures

Antibiotic susceptibility testing:
1. Enterotoxigenic Escherichia coli:
• Ampicillin
2. Campylobacter jejuni
• Erythromycin
3. Shigella:
• Ampicillin
4. SalmonellaAmpicillin


Case study 3

Laboratory investigations:
Urine culture is to test to identify the exact type of bacteria causing infection.
Culture on:
1.Blood Agar Plate (BAP)
2.Eosin Methylene Blue (EMB) agar
3.MacConkey Agar (MAC)
4.Ordinary nutrient agar
5.Triple Sugar Iron (TSI) agar
All are grown under anaerobic conditions except for Pseudomonas spp. such as P. aeruginosa as it is a strict aerobe.

Microscopy
1.Gram stain
2.Fungal stain
Morphology are studied in terms of the microorganisms’ shape, arrangement, response to strain and specific structures.
Biochemical tests are done to indicate the presence or absence of enzyme(s), a group of enzymes or a whole metabolic pathway. This helps to identify microorganisms.

	Gram staining	Cultures (Under anaerobic conditions)	Biochemical tests	Antibiotic Susceptibility test
Escherichia coli	Gram-negative (pink) bacillus	1. Blood agar: Gamma hemolysis 2. Eosin Methylene Blue agar: Colonies with metallic green sheen 3. MacConkey agar: Pink colonies	1. Indole test: Positive 2. Methyl Red (MR) test: Positive 3. Voges-Proskauer (VP) test: Negative 4. Simmon’s citrate test: Negative 5. Oxidase test: Negative 6. Urease: Negative 7. TSI acid slant/acid butt with gas, no H2S	-Susceptibility depends on the type of strains - Beta-lactamase resistant strains are not sensitive to penicillin and cephalosporin - Non-resistant strains are sensitive to ampicillin and trimethoprim-sulfamethoxazole
Enterococcus faecalis	Gram-positive (purple) cocci	1. Blood agar: Non hemolytic 2. MacConkey agar: Pink colonies with mucoid appearance 3. Bile Esculin Agar: Ferric citrate indicator will turn black	1.Indole test: Negative 2. Voges-Prokauer test: Positive	-Resistant to aminoglycoside, penicillin and vancomycin when given individually -A synergistic combination of aminoglycoside and cell wall-active antibiotics such as ampicillin and vancomycin
Klebsiella pneumoniae	Gram negative (pink) bacillus, a large capsule can be observed	1. MacConkey agar: Pink colonies with mucoid appearance	1. Indole test: Negative 2. Methyl Red test: Negative 3. Voges-Prokauer test: Positive 4. Urease test: Positive	- Isolates from nosocomial infections are frequently resistant to multiple antibiotics - Susceptible to aminoglycoside (eg. gentamicin) and cephalosporin (eg. cefotaxime)
Pseudomonas aeruginosa	Gram-negative (pink) bacillus	1. Blood agar: Beta-hemolysis 2. MacConkey agar: Colourless colonies 3. Ordinary nutrient agar: Blue-green colonies	1. Indole test: Negative 2. Methyl Red test: Negative 3.Voges -Prokauer test: Negative 4. Catalase test: Positive 5. Oxidase test: Positive 6. TSI agar: Negative (Growth with typical metallic sheen) 7. Pyocyanin test: Positive 8. Urease test: Positive/Negative 9. Fluprescein test: Positive	- Highly multidrug resistant - Combination therapy: Penicillin derivatives, Ceftazidime, Ciprofloxacin, Aztreonam, Imipenam
Serratia marcescens	Gram-negative (pink) bacillus	1. MacConkey agar: Pink colonies 2. Ordinary nutrient agar: Red colonies	1. Indole test: Negative 2. Methyl Red test: Negative 3. Voges-Prokauer test: Positive 4. Urease test: Negative	- Antibiotic resistance vary greatly - Isolates from nosocomial infections are frequently resistant to multiple antibiotics - Susceptible to aminoglycoside (eg. gentamicin) and cephalosporin (eg. cefotaxime)
Proteus mirabilis	Gram-negative (pink) bacillus	1. Blood agar with phenylethyl alcohol: Colonies do not have swarming effect 2. MacConkey agar: Colourless colonies	1. Indole test: Negative 2. Methyl Red test: Positive 3.Voges-Prokauer test: Negative 4. Catalase test: Positive 5. Urease test: Positive 6. TSI agar: Black butt	- Sensitive to ampicillin, aminoglycosides and trimethoprim sulfamethoxazole

Case Study 4
1.Chlamydia pneumoniae
• Obligate intracellular bacterium
• Does not gram stain
• Affects adults and children

2. Haemophilus influenza
• Pleomorphic gram-negative bacillus
• Affects children and adults (especially with COPD-Chronic Obstructive Pulmonary Diseases)

3. Moraxella catarrhalis
• Oxidase positive
• Gram-negative diplococcus
• Affects children and adults with COPD

4. Pseudomonas aeruginosa
• Glucose-nonfermenting
• Gram-negative bacillus
• Affects adults and children, diabetic adults, nosocomial, CF (Cystic Fibrosis) patients

5. Streptococcus pneumoniae
• Gram-positive lancet-shaped cocci
• Appear in pairs or short chains
• Affects adults (mainly elderly)

6. Mycoplasma pneumoniae
• Smallest free-living organism
• Lacks a bacterial cell wall
• Does not gram stain

7. Staphylococcus aureus
• Gram-positive cocci in clusters
• Coagulase-positive
• Catalase-positive
• Produces Beta-lactamase

8. Paragonimus westermani
• Fluke (Trematode)
• Affects children and adults in endemic areas

9. Adenovirus
• Enveloped dsDNA (double-stranded DNA)
• Affects children and adults

10. Parainfluenza virus Type I, II, III
• Enveloped ssRNA (single-stranded RNA)
• Affects infants and young children

11. Bordetella pertussis
• Coccobacillary, encapsulated gram-negative rod
• Negative blood culture

Lab investigations

Wet mounts
• Observe for microbe structure – bacillus, cocci, lancet-shaped, size, etc.

Gram stain
• Positive gram stain – microbe will stain purple/ blue
• Negative gram stain – microbe will stain red/ pink

Acid-fast bacterium stain
• Stains mycobacterium that do not gram-stain due to their high lipid content

Direct fluorescent-antibody stain
• Histologic stain to detect spirochetes

Peripheral blood films
• Observe microbial activity in blood
• Most respiratory tract infections would have negative blood smears

Enzyme immunoassay
• Identifies organisms with known antiserum
• Specific antibody linked to its homologous antigen

Latex agglutination assay
• Latex beads coated with specific antibody
• Agglutination will occur in the presence of the homologous bacteria

Blood cultures
• Positive blood culture – microbial growth (gold, yellow colonies, etc.)
• Negative blood culture – no microbial growth

Bacteriologic sputum cultured on enriched agar
• Bordet-Gengou agar

Antibiotic susceptibility tests

Penicillin – a general antibiotic for penicillin sensitive isolates
Ceftriazone
Erythromycin
Tetracycline – eg. Doxycycline
Praziquantel

Case study 5
Possible microorganisms

Microorganism	Test	Result
Staphylococcus aureus	● Gram-staining ● Culturing on mannitol salt/blood agar ● Coagulase test ● Catalase test ● TSI	● Gram-positive, cluster-forming cocci ● Yellow or gold colonies, drop in pH (yellow area) / ß-hemolytic ● Positive ● Positive ● Acid slant/acid butt
Enterococci	● Gram-staining ● Catalase test	● Gram-positive cocci, occuring singly, in pairs, or in short chains ● Negatives
Coagulase-negative staphylococci	● Gram-staining ● Culturing on blood agar ● Coagulase test ● Catalase test	● Gram-positive, cluster-forming coccus ● Yellow or gold colonies ● Negative ● Positive
Escherichia coli	● Gram-staining ● Culture on EMB/ MacConkey's agar ● TSI agar ● Urease test ● Indole test ● Citrate test	● Gram-negative rod ● EMB:Lactose-fermenting, blue-black colonies with metallic green sheen ● MacConKey:Lactose-fermenting, red colonies ● Acid slant/acid butt with gas but no H2S ● Negative● Positive ● Negative
Pseudomonas aeruginosa	● Gram-staining● Culture on EMB/ MacConkey's agar ● TSI● Oxidase test ● Indole test ● Citrate	● Gram-negative rod ● EMB/MacConkey:Non-lactose fermenting colonies ● Alkaline slant/alkaline butt ● Positive ● Negative ● Positive
Enterobacter species	● Gram-staining ● Culture on EMB/ MacConkey's agar ● Urease test ● Vogues-Proskauer test ● Citrate test	● Gram-negative rod ● EMB: Lactose-fermenting, brown dark -centered, mucoid colonies ● MacConkey:Lactose-fermenting, pink mucoid colonies ● Negative ● Positive ● Positive
Proteus mirabilis	● Gram-staining ● Culture on EMB/ MacConkey's agar ● TSI ● IMVIC ● Urease test	● Gram-negative cocci ● EMB/MacConkey:Non-lactose fermenting colonies ● Alkaline slant/acid butt with H2S ● Indole: Negative ● Methyl-red: Positive ● Vogues-Proskauer: Negative ● Catalase: Positive ● Positive
Klebsiella pneumoniae	● Gram-staining ● Culture on EMB/ MacConkey's agar ● TSI ● Indole test ● Urease test ● Citrate test	● Gram-negative rod ● EMB: Lactose-fermenting, brown dark -centered, mucoid colonies ● MacConkey:Lactose-fermenting, pink mucoid colonies ● Acid slant/acid butt with some gas production, no H2S ● Negative ● Positive ● Positive

Antibiotic:
Methicillin
Vancomycin
Penicillin
Oxacillin


Case study 6
Antibiotic Susceptibility test 5 antibiotics: vancomycin, ciprofloxacin , Erythromycin, bactrim and cefamandole

Gram-negative	Test	Result
Gardnerella vaginalis	● Morphology ● Oxidase ● TSI ● IMViC ● Laboratory diagnosis /culture	●Bacilli ● negative ● Acidic slant/acidic deep ● Catalase (-) ● Chocolate agar and HBT agar: Small, circular, convex, gray colonies ●Colistin-oxolinic acid blood agar: Beta-hemolysis
Escherichia coli	● Morphology ● Oxidase ● TSI ● IMViC ● Laboratory diagnosis /culture	●Bacilli ● negative ● Acidic slant/acidic deep ● I(+),M(+), Vi(-),C(-), U(-) ● EMB: green sheen,fermenting colonies ●MacConkey agar: fermenting colonies
Neisseria gonorrhoeae	● Morphology ● Oxidase ● TSI ● Laboratory diagnosis /culture	●Bacilli ● positive ● Acidic slant/acidic deep ●Giemsa-stained ●PCR and ELISA ●Immunofluorescence
Chlamydia trachomatis	● Morphology ● Oxidase ● Laboratory diagnosis /culture	●cocci ● positive ●Giemsa-stained ●PCR and ELISA ●Immunofluorescence
Pseudomonas aeruginosa	● Morphology ● Oxidase ● TSI ● IMViC ● Laboratory diagnosis /culture	●Bacilli ● positive ● Alkaline slant/ alkaline butt ●Catalase (+) ●EMB and MacConkey agar: non-fermenting colonies

Gram - positive	Enterococcus faecalis	Staphylococcus saprophyticus
Morphology	Cocci( in pairs)	Bacilli
Catalase test	-	+
coagulase	Nil	-
Laboratory diagnosis /culture	Blood agar: non-hemolysis	Mac Conkey’s agar: Spherical, irregular grape-like cluster in culture

Other microbes	Trichomonas vaginalis	Candida albicans	Mycoplasma hominis
Morphology	acridine orange : pear-shaped, motile, flagellated protozoan	single-celled, diploid fungus	round, pear shaped and even filamentous
Laboratory diagnosis /culture	Trichomonas Direct Enzyme Immunoassay and Fluorescent Direct Immunoassaysaline wet preparation : motile trichomonads and increased PMNs (ratio of PMNs to vaginal epithelial cells)	Blood agar plates: large, round, white or cream colonies	Mycoplasma GU Culture System: ‘fried egg’ and granular appearance colonies

Medical Microbiology- PBL 1

Learning issues:
1. Define the possible diagnosis
2. List down the possible causative agent

Case Study 1
Patient: Female/27 years old
Signs and symptoms: Fever, chills and dysuria
Suspected Diagnosis: Urinary tract infection
Specimen collected: Urine

The female patient in case 1 was diagnosed with urinary tract infection. UTI occurs due to the infection of microorganisms in the bladder,urethra and kidneys. It can be further classified as cystitis( bladder infection) or pyelonephritis( kidney infection). The patient showed common UTI symptoms seen in cystitis like dysuria(painful urination), fever and chills, but did not complain of back pain, or haematuria, hence it is likely that she is suffering from cystitis.

UTI occurs more frequently in woman as compared to men, due to the short urethra they have, allowing entry of bacteria into the urinary tract. The most common cause of UTI is Escherichia coli, a normal flora in the intestine and colon that enters and invades the urethra causing an infection. The second most likely bacteria that can cause UTI is Staphylococcus saprophyticus, as it usually infects woman in between the age of 20-40. Other microbes such as Klebsiella pneumoniae, Proteus mirabilis and Enterococcus species can also cause UTI, however, their occurrence is very low .

They are eliminated because:
a) Enterocoocus species usually occurs in patients who have undergone urinary tract surgery.
b) Proteus mirabilis often infect recurrent UTI patients that have structural abnormalities in their urinary system.
c) Klebsiella pneumoniae is involved in hospital-acquired infection and commonly infect immunocomprised individuals.

Most possible diagnosis: Escherichia coli and Staphylococcus saprophyticus
All the above characteristics were not observed in the patient and hence can be eliminated.
The two most likely cause of UTI are Escherichia coli and Staphylococcus saprophyticus.



Case Study 2
Patient: Female/29 years old
Signs and symptoms: Diarrhea
Suspected Diagnosis: Enterocolitis
Specimen collected: Stool

Types of enterocolitis:
1) Necrotizing enterocolitis
●Gastrointestinal disease that mostly affects premature infants, NEC involves infection and inflammation that causes destruction of the bowel intestine or part of the bowel.
● NEC typically occurs within the first 2 weeks of life, usually after milk feeding has begun

2) Autistic enterocolitis
●Autistic enterocolitis is a controversial term first used by British gastroenterologist Andrew Wakefield to describe a number of common clinical symptoms and signs which he contends are distinctive to autism.
● The existence of autistic enterocolitis is controversial, as the methodology of Wakefield's studies has been criticized and his results have not been replicated by other groups

3) Salmonella enterocolitis
● Most common type of food poisoning
● Infection in the lining of the small intestine caused by the bacteria Salmonella.
●Symptoms include diarrhea and abdominal pain

Most possible diagnosis: Salmonella enterocolitis
Reasons: Since necrotizing enterocolitis affects mainly infants but the patient is a 29-year-old female, it is highly unlikely that she is suffering from this disease. Moreover, it is not known to the medical technologist that the patient is suffering from autism. Hence, there is very low chance of her suffering from autism enterocolitis. The symptoms of salmonella enterocolitis include diarrhea which is one of the complaints as told by the female patient.



Case Study 3
Patient: Female/67 years old
Signs and symptoms: Fever, chills, bladder distension (bladder stretching); on indwelling catheter
Suspected Diagnosis: Urinary tract infection
Specimen collected: Urine

Indwelling catheters
Indwelling catheters avoid distension by emptying the bladder continuously into a bedside drainage collector. Individuals with indwelling catheters are encouraged to maintain a high fluid intake in order to prevent bacteria from accumulating and growing in the urine.

Possible agents:
● Many different Gram-negative organisms colonize urinary catheters, often becoming invasive infections.
●The most commonly isolated pathogens are Escherichia coli and Enterococcus spp.E.coli uses fimbriae to adhere to the urinary epithelium, thereby reducing the risk of being washed away.
● Infections caused by Proteus spp. are more likely in patients who have stones as Proteus spp. have urease activity that raises urinary pH, thus encouraging stone formation.
● Staphylococcus saprophyticus is a common isolate from sexually active females.
● Other intestinal bacteria, including Klebsiella pneumoniae (K.pneumoniae), Proteus mirabilis (P.mirabilis) , and Citrobacter.
●Others include Pseudomonas aeruginosa (P.aeruginosa), Enterobacter, and Serratia species, gram-positive organisms, including Enterococcus species, and S. saprophyticus .

Most possible diagnosis: Staphylococcus saprophyticus, Klebsiella pneumoniae, Proteus mirabilis and Enterococcus
UTI in this patient should be due to the presence of the catheter in the urethra. Hence these microbes might the possible reason.

Case Study 4
Patient: Male /68 years old
Signs and symptoms: fever, chills, excessive phlegm, breathing problems Suspected Diagnosis: Bronchitis
Specimen collected: Sputum

Information on Bronchitis
Inflammation of the mucous membrane in the lungs' bronchial passages
Narrowed bronchial passages shuts off the tiny airways in the lungs
Results in coughing spells, thick phlegm and breathlessness
Two forms: acute (lasts less than 6 weeks) and chronic (more than two years)

Acute bronchitis
●responsible for the hacking cough and phlegm production that sometimes accompany an upper respiratory infection
● In most cases the infection is viral in origin, but sometimes it's caused by bacteria
● very common among both children and adults

Chronic bronchitis
● a serious long-term disorder that often requires regular medical treatment

Possible agents
1) Adenovirus
● Non-enveloped double-stranded linear DNA
● Icosahedral nucleocapsid with a fiber protruding from each of the 12 vertices
●Causes bronchitis when it affects the lower respiratory tract

2) Bordetella
●Small, coccobacillary, encapsulated gram negative rod
● Restricted to the respiratory tract (negative blood culture)
●Isolated and grown on Border-Gengou agar

3)Parainfluenza virus
●Single stranded RNA negative-strand viruses

4) Streptococcus pneumoniae
● Gram positive lancet-shaped cocci
● Arranged in pairs or short chains
●Higher mortality in persons aged 65 and above

5) Chlamydia pneumoniae
●Obligate intracellular bacteria
●Require host cells for growth
● Causes upper and lower respiratory tract infections

Most possible microbes:
These microbes expressed similar symptoms as the patient in this case study. Hence, they are the most likely microbes to be causing this illness.


Case Study 5
Patient: Male /37 years old
Signs and symptoms: fever, Swelling around operation wound
Suspected Diagnosis: Wound Infection
Specimen collected: wound swab

Wound Infection caused by bacteria
● This is because swelling is one of the hallmarks of inflammation due to infection by either endogenous factors like tissue necrosis or exogenous factors like microorganism infections.
● Fever, on the other hand, is a common manifestation of infection and inflammation that is caused by many bacterial products eg endogenous or exogenous pyrogens.
● Most wound infections are caused by normal flora found on the skin/body.

Pathogens related to different surgical procedures/operations:

Pathogens Commonly Associated with Wound Infections and Frequency of Occurrence are as follows:
● Staphylococcus aureus (20%)
● Coagulase-negative staphylococci (14%)
● Enterococci (12%)
● Escherichia coli (8%)
● Pseudomonas aeruginosa (8%)
● Enterobacter species (7%)
● Proteus mirabilis (3%)
● Klebsiella pneumoniae (3%)
● Other streptococci (3%)
● Candida albicans (3%)
● Group D streptococci (2%)
● Other gram-positive aerobes (2%)Bacteroides fragilis (2%)

Most possible microbes:
However, out of all the organisms, the most common bacteria involved in wound infection due to operation was found to be Staphylococcus aureus, which accounts for 17-20% of the cases reported. Out of these cases, 40-50% are due to MRSA (Methicillin-resistant Staphylococcus aureus).

Case Study 6
Patient: Female/37 years old
Signs and symptoms: Fever, pain during urination and virginal discharge
Suspected Diagnosis: Urinary tract infection
Specimen collected: Vaginal discharge

Possible agents:
1) Trichomoniasis
A sexually transmitted disease caused by the anaerobic, flagellated protozoa Trichomonas vaginalis.
Symptoms of Trichomoniasis include painful urination, fever, discharge greenish-yellow vaginal fluid, lower abdominal pain and discomfort during sexual intercourse.

2) Bacterial Vaginosis
It is caused by imbalance of bacteria flora in vagina. Usually, it is characteristic by the overgrowth of Gardnerella vaginalis and Gardneralla mobiluncus,.
Gardnerella bacteria is facultative anaerobic and gram-negative, while Mycoplasma hominis
It symptoms includes gray vaginal discharge and painful urination.

3) Vaginal Candidiasis
An infection caused by yeast, Candida albicans.
Its morphology appearance is normally single-celled.
Symptoms includes discomfort during urination and produce cottage cheese-like vaginal discharge or irritation in genital area

4)Gonorrhea
Another sexually transmitted disease caused by Neisseria gonorrhoeae, which is a gram-negative, cocci and aerobic bacteria.
Which produces symptoms like fever, yellowish discharge and urethritis.

5)Chlamydia
A sexually transmitted disease caused by gram-negative cocci and aerobic bacteria Chlamydia trachomatis.
Chlamydia trachomatis required a host organism to survive.
Patients with Chlamydia will experience symptoms like fever, abnormal discharge and painful urination.

Most possible microbes:
Since Gonorrhea, Trichomoniasis and Chlamydia expressed similar symptoms as the patient in this case study, they are the most likely microbes to be causing this illness.

References
1. http://www.mayoclinic.com
2. http://www.healthatoz.com
3. http://www.nlm.nih.gov/medlineplus/encyclopedia.html
4. http://en.wikipedia.org/wiki/Wiki