Chapter

JOHN W. FOSTER ZARRINTAJ ALIABADI JOAN L. SLONCZEWSKI

MICRO BIOLOGY THE HUMAN EXPERIENCE

Basic Concepts of Infectious Disease Supplemental Case History

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Scenario

Kelly is a 16-year-old girl who is undergoing treatment (successfully, so far) for leukemia. Over a period of a couple of days, she began to experience a persistent full bladder feeling that did not go away, even after she peed.

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Signs and Symptoms

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Kelly told her mother about her problem when she noticed what appeared to be blood in the toilet after she went to the bathroom in the morning. She also mentioned that peeing had become painful with a burning/stinging sensation. Her mother took her to see her primary care physician who ordered urine and blood cultures.

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Signs and Symptoms

The physician notes that Kelly has a low grade fever.

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Kelly gave a urine sample, which was cloudy and tested positive for blood on a urine test strip in the physicians office.

The urine sample was sent to a reference laboratory for cultures and additional tests.

Is the dipstick result considered a sign or symptom for Kellys disease?

In Kellys description to her mother of how she felt, what can be considered a sign and what can be considered a symptom?

Is the physician-observed low-grade fever considered a sign or a symptom of an ongoing disease?

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Testing

Microscopic analysis of a drop of Kellys urine showed numerous white blood cells, indicating a bacterial infection.

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Are the bacteria likely causing Kellys disease pathogens?

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Testing

Bacteria were cultured from Kellys urine and found to be Gram-positive Staphylococci. Several species of Staphylococcus are human skin microbiota.

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Would the bacteria causing Kellys disease be considered a primary or opportunistic pathogen?

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Diagnosis

The bacteria that were grown in culture from Kellys urine were identified through laboratory testing as Staphylococcus saprophyticus. In humans, S. saprophyticus is a member of the normal microbiota of the female genital tract and perineum (the region between the vagina and anus).

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What host factors may have contributed to Kelly developing a Urinary Tract Infection (UTI) with S. saprophyticus?

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Treatment

After consultation with Kellys oncologist, the physician administered the medically recognized standard of care for treating uncomplicated UTIs. The UTI symptoms resolved fully with this treatment.

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According to the American Association of Family Physicians, the recommended treatment for an uncomplicated UTI is oral TMP-SMX (Bactrim)

twice daily for 3 days.

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Additional Considerations

Is Kelly at continued risk of developing a UTI caused by S. saprophyticus?

What portal of entry did the bacteria use to cause Kellys UTI?

Identify the reservoir of infection in this case.

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This concludes the Lecture PowerPoint

presentation for Chapter 2

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