Case One
Patient: Khong Fay Seah, Female, 27, outpatientThe urinary tract includes the kidneys, ureters, bladder and urethra. As compared to men and children, women are of greater risk in acquiring urinary tract infection due to the shorter urethra and close proximity between the anus, urethra and vagina.
There are two classifications of UTI, mainly lower and upper. While lower UTI involves the bladder and urethra, upper UTI implicates the ureters and kidneys. The common symptoms of lower UTI includes back pain, blood in the urine (hematuria), cloudy urine, fever, polyuria, general discomfort (malaise) and painful urination (dysuria). As for upper UTI, it involves high fever, shaking chills, nausea and may or may not include symptoms of lower UTI.
Common Causative Organisms | Supporting reason(s) | Investigation(s) |
Bacteria | ||
Escherichia Coli (Gram-negative bacillus) | Occurs in more than 70% of UTI cases Present in human colon as nature flora and is present in feces | -Blood Agar -EMB Agar (Green sheen colonies) -MacConkey’s Agar (Pink colonies) |
Staphylococcus saprophyticus and aureus (Gram-positive cocci) | Causes community-acquired urinary tract infection in young woman | -Mannitol-salt Agar (Yellowish-gold colonies) |
Enterococcus faecalis (Gram-positive cocci) | Present in human colon as nature flora and is present in feces Largely involved in lower UTI | -EMB Agar (Coloured colonies) MacConkey’s Agar (Coloured colonies) |
Proteus mirabilis (Gram-negative bacillus) | Vigorously motile contributing to their ability to invade urinary tract Present as normal flora in colon | -Phenylethyl alcohol containing blood agar (inhibit swarming) -EMB (Colourless colonies) -MacConkey’s agar |
Klebsiella pneumoniae (Gram negative bacillus) | Involves in nosocomial infections especially UTI Common causative agent of patients with catheter | -EMB Agar (Coloured colonies) MacConkey’s Agar (Coloured colonies) |
Enterobacter spp. (Gram-negative bacillus). | Frequently found in large intestine | EMB Agar (Coloured colonies) -MacConkey’s Agar (Coloured colonies) |
Pseudomonas aeruginosa (Gram-negative bacillus) | Opportunistic pathogen 10% of human carry it as nature flora of colon | EMB Agar (Colourless colonies) MacConkey’s Agar |
Fungal | ||
Candida albicans | Frequently infects people who have an impaired immune system or a bladder catheter in place. | Sabouraud’s Agar |
Virus | ||
Herpes Simplex Virus Type 2 (HSV-2) | Common causative agent of genital lesions Proliferates in female genital tract | Identify by immunological tests |
Protozoa | ||
Trichomonas vaginalis | Transmitted via sexual activities Causes yellow-green vaginal discharge with a strong odor | Wet mount examined for trichomonads |
culture (colourless) and on the right lactose-fermenter (metallic green sheen) on EMB agar
(Taken from http://www.google.com/ > images > search >E.coli on EMB)
Fig1.2 Lactosing Fermenting organism forming pink
colonies on MacMonkey Agar
(Taken from http://www.google.com/ > images > search >E.coli on MacConkey)
Fig 1.3 Staphylococcus saprophycius on Mannitol-salt Agar
(Taken from http://www.google.com/ > images > search >Staphylococcus on Mannitol-salt Agar)
Though Trichomonas vaginalis and Herpes Simplex Virus Type 2 (HSV-2) lead to UTI, it mainly causes vaginitis instead which leads to vaginal discharge. These symptoms is not observed for Ms Khong Fay Seah Also, candidal urethritis is in healthy women unless catheter is in placed and thus we rule out Candida albicans infection.Done by: Jiaxin
Case 2
- Enteritis: which is the inflammation of the small intestine
- Colitis: which is the inflammation of the large intestine, especially the co
- Pseudomembranous enterocolitis
- Thought to be caused by a toxin-producing strain of Clostridium difficile
- Necrotic mucosa is replaced by a pseudomembrane filled with staphylococci, leukocytes, mucus, fibrin, and inflammatory cells
- Has occurred postoperatively in debilitated patients who has undergone abdominal surgery and in patients treated with broad-spectrum antibiotics (Ampicillin, clindamycin, and cephalosporins are suspected as causative factors)
- Immunocompromised patients are at increased risk for this disease
- Salmonella enterocolitis
- An infection in the lining of the small intestine caused by Salmonella
- It occurs when food or water that is contaminated with Salmonella are ingested
- Enterocolitis caused by parasites
- Enterocolitis caused by medications
- Necrotizing enterocolitis (NEC)
- Usually occurs in premature neonates (less than 34 weeks’ gestation) and those of low birth weight (less than 5 lb [2.3 kg]). NEC is occurring in more neonates, possibly because of the higher incidence and survival of premature and low-birth-weight neonates
- Since it is most commonly seen in neonates and premature and low-birth-weight neonates, the patient is probably not suffering from this type of enterocolitis
Common Causative Organisms | Supporting reasons | Investigations |
Salmonella spp. (Gram-negative) | - Certain strains of Salmonella can infect the lining of the small intestine causing Salmonella enterocolitis | Culture on: - Salmonella- Shigella (SS) plate - BAP - MAC - Campylobacter Selective Medium - Thiosulphate-citrate bile sucrose agar (TCBS) - Selenite F broth - Alkaline Peptone Water (APW) - Enterococcosel Agar with 6ug/mL of vancomycin - Sorbitol MAC for enterohaemorrhagic E. coli All are grown under aerobic conditions except for Campylobacter selective medium which requires anaerobic incubation Microscopy: - Gram stain - Wet mount - Parasite - Stool ova & cyst |
Shigella spp. (Gram-negative) | - Causes dysentery (severe diarrhoea) that result in the destruction of the epithelial cells of the intestinal mucosa in the cecum and rectum | |
Campylobacter spp. (Gram-negative) | - Causes campylobacteriosis, an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, mostly including cramps, fever and pain | |
Clostridium difficile (Gram-positive) | - Toxins produced by this organism are thought to cause Pseudomembranous enterocolitis | |
Vibrio spp (Gram-negative) | - Commonly found in seafood and may cause gastroenteritis (diarrhoea) | |
- Enteropathogenic Escherichia coli [EPEC](Gram-negative) - Enterohaemorrhagic E. coli - Diarrhoegenic E. coli [ETEC, EIEC and EAEC] - Yersinia spp. (Gram-negative) | - These organisms are possible causative agents of enterocolitis | |
Parasites | - The presence of parasites may cause irritation and inflammation of the intestines and thus causing diarrhoea |
Done by: Azhar
Case 3
Patient: Maisy Hong, Female, 67, inpatient
Common Causative Organisms | Supporting reasons | Investigations |
Escherichia coli (Gram-negative) | - Predominant causative agent of UTI | Culture on:
|
Pseudomonas aeruginosa (Gram-negative) | - Causes infection in almost anywhere in the body but main infections include UTI | |
Enterococcus faecalis (Gram-positive) | - Causes UTI especially in hospitalized patients | |
Klebsiella pneumoniae (Gram-negative) | - Emerging as an important nosocomial pathogen | |
Enterobacter cloacae (Gram-negative) | - Important nosocomial pathogens that cause a variety of infections including UTI | |
Serratia marcescens (Gram-negative) | - Causes UTI in hospitalized patients associated with the use of catheter | |
Proteus mirabilis (Gram-negative) | - Once attached to the urinary tract, it infects the kidney more commonly than E. coli. |
Staphylococcus saprophyticus, Candida albicans, Adenovirus also causes UTI. UTI caused by S. saprophyticus is particularly in sexually active young woman so it is not possible in this case. Candida albicans might not be the causative agent in this case because the patient does not have symptoms such as itching and vaginal discharge that are seen in vaginitis (infection by Candida). Adenovirus (Types 11 and 21) causes hemorrhagic cystitis. It is also not a possible causative agent because prominent symptoms such as hematuria and dysuria are not observed in the patient.
Done by: Ming Boon
Case 4
Name: Tong Wei Hong, Male, 68, outpatient
Possible causative agents. (Types of microorganisms) | Supporting reasons | Preliminary lab investigations |
Streptococcus pneumoniae | These are the most common microorganisms that caused bacterial bronchitis in middle-aged and older people. Symptoms of bronchitis will be seen. | Gram staining test and identify colony characteristics under a light microscope. Biochemical identification test to detect the presence of catalase. Identify type of haemolysis on blood agar. Antibiotic susceptibility test using penicillin, erythromycin and vancomycin. |
Haemophilus influenza | Gram staining test and identify colony characteristics under a light microscope. Biochemical identification test to detect the presence of oxidase. Antibiotic susceptibility test using Ceftriaxone, trimethoprim-sulfamethoxazole. Identify microorganism on heated blood agar enriched with factor X( a heme compound) and factor Y (NAD). | |
Moraxella catarrhalis | Gram staining test and identify colony characteristics under a light microscope. Biochemical identification test to detect the presence of oxidase. Antibiotic susceptibility test using erythromycin and tetracycline. | |
Mycoplasma pneumoniae | Mycoplasma pneumoniae and Chlamydia pneumoniae often cause bacterial bronchitis in young adults (5-15years old). Symptoms of bronchitis will be seen. For Mycoplasma pneumoniae, it will cause primary atypical pneumonia in which the body will responds with a persistent unproductive cough in an attempt to clear lungs. For Chlamydia pneumoniae, it causes 5% of cases of bronchitis and it usually cause atypical pneumonia. | Serologic testing using antibodies. |
Chlamydia pneumoniae | Giemsa stain or by immunofluorescence identify colony characteristics. Perform cell cultures treated with cycloheximide. Antibiotic susceptibility test using tetracycline such as doxycycline and macrolides such as erythromycin can be conducted. | |
Bordetella pertussis | It is responsible for the disease (pertussis) commonly known as whooping cough which is a type of bronchitis. Symptoms include cough and excessive production of mucus. | Gram staining test and identify colony characteristics under a light microscope. Biochemical identification test to detect the presence of oxidase. Perform cell culture in Bordet-Gengou medium. Serologic testing using antibodies. |
Done by: Michelle
Case 5
Patient: Wong Fei Hong, Male, 37, outpatient
Common Causative Organisms | Supporting reasons | Investigations |
Staphylococcus aureus (Gram-positive) | - Most common microorganism present in surgical-wound infection | Culture on: anaerobic condition
|
Pseudomonas aeruginosa (Gram-negative) | - Cause infections in the body, primarily wound infection due to burns | |
Bacteriodes fragilis (Gram-negative) | - Causes a variety of infections | |
Clostridium perfringens (Gram-positive) | - Common in open-wound infections |
Other causative agents that cause wound infection, such as Pasturella multocida which are transmitted by animals and Wuchereria bancrofti, transmitted by mosquitoes primarily in Africa, were ruled out in this investigation.
Done by: Yvonne
Case 6
Patient: Ong Fei Fei, Female, 37, outpatient
Common causative agents | Supporting reasons | Investigations |
Eschericia coli (gram-neg bacteria) | Normal flora of anterior urethra as well as vagina Common agent in UTI | Culture on: -BAP Microscopy: -Fungal stain -Wet mount -Gram stain |
Candida albicans (fungus-yeast) | - Opportunistic pathogen which exist as normal flora in the vagina of some women - Causes infection when normal flora of the genital tract is disrupted - Usually seen in patients with indwelling catheter or on antibiotic treatment | |
Staphylococcus aureus (gram-positive cocci) | - Found on mucosal lining of vagina - Overgrowth may lead to infection of the urethra | |
Proteus mirabilis (gram-neg bacteria) | - Found as normal flora in the genital tract - Possible agent of UTI | |
Staphylococcus saprophyticus (gram-positive cocci) | - 2nd most common UTI agent in sexually active women | |
Trichomonas vaginalis (protozoa) | -Causes trichomoniasis -Greenish vaginal discharge is watery, foul-smelling. | |
Chlamydia trachomatis (gram-neg) | - Obligate intracellular bacterium - Cause urethritis in both male and female | |
Klebsiella pneumoniae (gram-neg) | - Non-motile - Causes UTI among other diseases - Ubiquitous in the enviroment | |
Pseudomonas aeruoginosa (gram-neg rod) | - Aerobic bacterium - Motile | |
Serratia marcesens(gram-neg rod) | - Facultative anaerobe - Causes UTI | |
Gardnerella vaginalis (gram- variable rod) | - Agent in bacterial vaginosis - Vaginal discharge is pungent, fishy-odour | |
Mobiluncus sp. (gram- +ve rod) | - Causative agent in bacterial vaginosis - Anaerobic bacterium | |
Enterococcus faecalis (gram- +ve cocci) | - Found in the colon - Alpha-hemolytic |
The above are the possible causative agents of UTI in this patient. Other possible agents like Ureaplasma ureatylticum and Mycoplasma genitalium are excluded as they cause urethritis in men only.
Done by: ShahirahReferences:
2. http://www.merck.com>urinary tract infection
3. http://www.wrongdiagnosis.com>enterocolitis
4. http://www.nlm.nih.gov/medlineplus>salmonella enterocolitis
5. http://en.wikipedia.org/wiki/Main_Page>enterocolitis
6. http://www.wrongdiagnosis.com>bladder distension
7. http://www.niddk.nih.gov>overcoming bladder disease
8. http://www.cdc.gov>guideline for prevention of catheter-associated urinary tract infections
9. Levinson W. 2006. Review of Medical Microbiology and Immunology, 9th edition. McGraw Hill Companies
10. http://www.merck.com>bronchitis
11. http://respiratory-lung.health-cares.net
12. http://www.bact.wisc.edu>the microbial world>normal flora
13. http://www.columbia.edu>urinary tract infections
14. http://www.hmc.psu.edu>urinary tract infections
15. http://en.wikipedia.org/wiki/Main_Page>proteus mirabilis
16. http://www.searo.who.int/en>urinary tract infection
17. Brooks, Geo F, Butel J & Morse S. 2004. Jawetz, Melnick, and Adelberg's Medical Microbiology, 23rd edition
Sorry for the tables! Did my best already!
No comments:
Post a Comment