Microbiology 20 Clinical Correlate 2

E. coli and Staph Infection

Objectives:

  • Understand that some bacteria are part of normal flora.
  • Learn about the causes of E.coli and Staph infection
  • Know what nosocomial infections are
  • Demonstrate understanding of how MRSA is spread and its importance

When a bacterium is part of the bacteria living in our body, it is noted to be part of our normal flora. The normal flora is the collection of microorganisms that live in our body. Normal flora must be kept in check within the body to keep a healthy state within the body. Two examples of common normal flora that can cause infection are Staphylococcus aureus and Escherichia coli.

While S. aureus is a common, Gram-positive member of the normal flora, MRSA is a strain of S. aureus that has become different than the more common Staph bacteria. MRSA is resistant to the antibiotic Methicillin, thus the name Methicillin ResistantStaphylococcus aureus. Staphylococcus bacteria are commonly found on many sites of the body including the face, hands, axilla (underarm) and groin. However, it is most commonly found in the nares (nasal passages). When a bacterium is part of the bacteria living in our body, it is noted to be part of our normal flora. The normal flora is the collection of microorganisms that live in our body.In recent years, MRSA has become a major problem in the hospital setting and is a common cause of nosocomial (hospital acquired) infections. The primary route of MRSA transmission between people within the hospital seems to be from patient to patient, carried on the hands of hospital personnel! Also, MRSA may attach to environmental objects and spread that was as well. These environmental objects (such as tissue or pen or cup) are called fomites.

On the other hand, E. coli is probably the most common Gram-negative bacilli in the GI tract of humans. It is the cause of 80% of urinary tract infections (UTIs) as well as gastroenteritis (diarrhea). Most often, diarrhea infection is caused by E. coli that is acquired from the environment often for travelers producing Travellers’ diarrhea. Most E. coli cause diarrhea is self-limited meaning that you cannot pass it on to other people and will not be too dangerous. An exception is the O157:H7 (important to remember!) strain of E. coli, which is usually acquired from poorly cooked cow meat. This is an enterohemorrhagic strain of E. coli which can lead to HUS (hemolytic uremic syndrome). HUS is a syndrome that is characterized by hemolytic anemia (the red blood cells are destroyed), thrombocytopenia (not enough platelets to clot the blood) and acute renal (kidney) failure. The O in O157:H7 stands for the type of LPS that is present in the bacteria. The H in O157:H7 stands for a protein on the flagella of the bacteria. The flagella are used for allowing the bacteria to move toward attractants.

Essay Prompt (Due March 10, 2018 at 11:30am)

As a health care provider in LA County you will often run into infections caused by both MRSA and O157:H7 E. coli. For this clinical correlate, write a one-page essay on comparing MRSA and O157:H7 E. coli infections in LA County. For this information you need to go to the LA County Acute Communicable Disease Control Website:

and search for the two infections using the search box.

Explain what the infections are and how common they are in LA Country. Also include any suggestions on how to decrease infection over the next years.

Vocabulary to know from this Clinical Correlate:

Normal Flora

Nares

Nosocomial

Urinary Tract Infection

Gastroenteritis
Self-limited

For all clinical correlates you should also start to know about the infection discussed including:

Name of Disease

Name of Pathogen

Type of Pathogen

How it is Spread