Patient 3: Maisy Wong (2nd entry)

Complaints (key words): Fever, chills, bladder distension. Patient is on indwelling catheter.

In this case, the urinary tract infection (UTI) can be caused by several reasons:

1) The patient is a 66 years old female. Hence the UTI may also be due to post menopause.
It is said that ‘the risk for UTI, both symptomatic and asymptomatic, is highest in women after menopause’ [2]. This may be due to bladder or uterine prolapse leading to incomplete bladder emptying [4]. Menopause may cause biologic changes. This in turn ‘put older women at particular risk for primary and recurring UTIs’ [2].

Post menopausal women will encounter estrogen loss. With this, the walls of urinary tract will thin out hence weakening the mucous membrane and reducing its ability to resist bacteria [2]. The bladder may also lose its elasticity, which eventually leads to failure to empty completely [2]. This points out to the cause of bladder distension for this patient.

Urethritis may occur in post menopausal women, whereby the tissues of the urethra and bladder become thinner and drier [5]. This brings about the infection.

Possible microorganisms: Klebsiella pneumoniae, Enterococci bacteria, E.coli and Proteus mirabilis.

2) Upper UTI brought by indwelling catheter (pyelonephritis)[1].
If a urinary catheter is left in place for a long time, bacteria will grow in it. A harmful infection may occur if the number of bacteria becomes large or if specific pathologic bacteria grow in the urinary tract [7].

Possible microorganisms: E. coli, Klebsiella and Proteus species, candida albicans.

3) Upper UTI caused by cystitis (lower UTI). Bacteria on catheter can infect the bladder, causing cystitis [3]. Although infection caused by catheter is associated with pyelonephritis, the bladder can also be infected as the catheter is inserted into the bladder.
When bacteria enter the bladder, they are usually eliminated through urination [6]. Infection will occur when bacteria multiply faster than they are removed by urination [6].

Older people have higher risk of developing cystitis due to incomplete emptying of the bladder associated with such conditions as benign prostatic hyperplasia (BPH), prostatitis and urethral strictures [6].

Possible microorganisms: E. coli, Staphylococcus saprophyticus, Klebsiella, Enterobacter and Proteus species.

I have researched on the morphology of the possible microorganisms. It has been collated together with Samantha's research. The table can be found in the entry below titled 'Morphology and Characteristics of Microorganisms in UTI'.

Now that I have listed the possible microorganisms for each posible cause of UTI, the next step is to find out the tests used in determining presence/absence of these microorganisms. This will be focused on in the next entry.

References:
[1] G.Brooks, J.Butel and S.Morse. (2004). Jawetz, Melnick & Adelberg’s Medical Microbiology
[2] http://adam.about.com/reports/000036_3.htm
[3] http://kidney.niddk.nih.gov/kudiseases/pubs/utiadult/
[4] http://www.emedicine.com/EMERG/topic626.htm
[5] http://scc.uchicago.edu/urethritis.htm
[6] http://en.wikipedia.org/wiki/Cystitis
[7] http://www.nlm.nih.gov/medlineplus/ency/article/000483.htm