Gram-Negative Bacilli - Enteric Tract Flashcards by 1994tso .

Which Sketchy image represents Klebsiella pneumoniae, Enterobacter spp., and Serratia marcescens?

‘Enterodactyl, Triserratiatops, and Kleb-tail’

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Salmonella enteritidis and Salmonella typhi?

‘The Salmon Dinner’

Chicken — S. enteritidis

Seagull — S. typhi

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Shigella spp.?

‘She-Gorilla Circus’

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Escherichia coli (ETEC, EHEC)?

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Yersinia enterocolitica and Yersinia pestis?

“Yersin’s Pets”

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Campylobacter jejuni?

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Vibrio spp.?

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Helicobacter pylori?

How well did you know this?

Not at all

Perfectly

Which Sketchy image represents Proteus mirabilis?

How well did you know this?

Not at all

Perfectly

Note: this is Klebsiella pneumoniae, Enterobacter spp., and Serratia marcescens.

How well did you know this?

Not at all

Perfectly

Note: this is Salmonella enteritidis (chicken) and Salmonella typhi (seagull).

How well did you know this?

Not at all

Perfectly

Note: this is Shigella spp..

‘She-Gorilla Circus’

How well did you know this?

Not at all

Perfectly

Note: this is Escherichia coli (ETEC, EHEC).

How well did you know this?

Not at all

Perfectly

Note: this is Yersinia enterocolitica and Yersinia pestis.

How well did you know this?

Not at all

Perfectly

Note: this is Campylobacter jejuni.

How well did you know this?

Not at all

Perfectly

Note: this is Vibrio spp..

How well did you know this?

Not at all

Perfectly

Note: this is Helicobacter pylori.

How well did you know this?

Not at all

Perfectly

Note: this is Proteus mirabilis.

How well did you know this?

Not at all

Perfectly

Which infectious agent is which in this image?

Enterodactyl;

triserratiatops;

kleb-tail (ankylosaurus)

How well did you know this?

Not at all

Perfectly

Enterobacter spp., Serratia marcescens, and Klebsiella pneumoniae bacteria are gram-_________ _______.

Enterobacter spp., Serratia marcescens, and Klebsiella pneumoniae bacteria are gram-negative bacilli.

How well did you know this?

Not at all

Perfectly

Name two nosocomial infections that are common to the three following bacteria:

Enterobacter spp.

Serratia marcescens

Klebsiella pneumoniae

Pneumonia;

UTI

How well did you know this?

Not at all

Perfectly

Enterobacter spp., Serratia marcescens, and Klebsiella pneumoniae all cause ________ pneumonias and UTIs that are often multi-_____ _________.

Enterobacter spp., Serratia marcescens, and Klebsiella pneumoniae all cause nosocomial pneumonias and UTIs that are often multi-drug resistant.

How well did you know this?

Not at all

Perfectly

All three of the following ferment what disaccharide?

Enterobacter spp.

Serratia marcescens*

Klebsiella pneumoniae

Lactose

*ferments lactose very slowly

How well did you know this?

Not at all

Perfectly

Name three infectious agents that all exhibit the following:

1. Cause pneumonias and UTIs

2. Are frequently nosocomial and multi-drug resistant

3. Are gram-negative bacilli

4. Ferment lactose

Enterobacter spp.*
Serratia marcescens**
Klebsiella pneumoniae*

*ferments lactose very slowly

How well did you know this?

Not at all

Perfectly

Lactose fermenting appears as _______ (color) colonies on _________ agar. * Enterobacter spp.* * Serratia marcescens\** * Klebsiella pneumoniae* \*ferments lactose very slowly

Lactose fermenting appears as **pink** colonies on **MacConkey** agar. * Enterobacter spp.* * Serratia marcescens* * Klebsiella pneumoniae*

Which of the following display motility? * Enterobacter spp.* * Serratia marcescens* * Klebsiella pneumoniae*

***Enterobacter spp.*** ***Serratia marcescens***

Name the shape and gram-state of the following three bacteria. ## Footnote ***Enterobacter spp.*** ***Serratia marcescens*** ***Klebsiella pneumoniae***

All **gram-negative bacilli** (enteric tract)

What color pigment does *Serratia marcescens* produce?

Red

What are the three A's of *Klebsiella pneumoniae*?

1. **A**lcoholics 2. **A**spiration 3. **A**bcesses

Are any of the following encapsulated? ## Footnote *Enterobacter spp.* ***Serratia marcescens*** ***Klebsiella pneumoniae***

*Klebsiella pneumoniae*

*Klebsiella pneumoniae* is characterized by infected patients coughing up a '\_\_\_\_\_\_\_ \_\_\_\_\_\_\_' sputum.

*Klebsiella pneumoniae* is characterized by infected patients coughing up a '**currant** **jelly**' sputum.

**True/False**. *Klebsiella pneumoniae* can produce abcesses and cavitary lesions.

**True**. | (Needs to be differentiated from TB)

*Klebsiella pneumoniae* is \_\_\_\_\_\_\_\_\_\_\_-positive.

*Klebsiella pneumoniae* is **urease**-positive.

*Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are gram-\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_.

*Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are gram-**negative** **bacilli** (enteric tract).

**True/False**. *Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are immotile.

**False**. *Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are ***motile***.

Due to production of \_\_\_\_\_, *Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) form _________ colonies on **Hektoen** enteric agar.

Due to production of **H₂S**, *Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) form **black** colonies on **Hektoen** enteric agar. (Thus, differentiating them from Shigella spp., which form green colonies on HE)

**True/False**. *Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are encapsulated and grow best in acidic conditions.

**False**. *Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are encapsulated and are ***acid-labile*** (sensitive to acid).

Why might an individual on cimetidine (or another H2-blocker) be at increased risk of *Salmonella spp.* infection?

*Salmonella spp.* (e.g. *S. enteritidis*, *S. typhi*) are **acid-labile**.

\_\_\_\_\_\_\_\_\_\_ are the main reservoir for *S. enteritidis*. *S**. typhi* colonize the ___________ of affected carriers.

**Chickens** are the main reservoir for *S. enteritidis*. *S**. typhi* colonize the**gallbladder** of affected carriers.

List the main features of typhoid fever (*Salmonella typhi*).

Fever; 'rose spots' abdominal rash; khaki-green ('pea soup') stools

\_\_\_\_\_\_\_\_\_\_ _____ are the most common cause of osteomyelitis in sickle cell patients.

***Salmonella** **spp**.* (e.g. *S. enteritidis*, *S. typhi*) are the most common cause of osteomyelitis in sickle cell patients.

How is *S. enteritidis* infection usually treated? How is *S. typhi* infection usually treated?

**Supportive care** (usually resolves on its own; no antibiotics needed); ## Footnote **fluoroquinolones**

There is an available vaccine for which *Salmonella spp*.? What type of vaccine?

*S. typhi*; live attenuated

*Salmonella* _________ usually causes a self-limited, ___________ gastroenteritis.

*Salmonella **enteritidis*** usually causes a self-limited, ***inflammatory*** gastroenteritis.

*Salmonella* *enteritidis* and *Salmonella typhi* possess a type ____ secretion system that delivers effector **proteins** directly into _____ cells.

*Salmonella* *enteritidis* and *Salmonella typhi* possess a type **III** secretion system that delivers effector **proteins** directly into **host** cells.

*Salmonella* *enteritidis* and *Salmonella typhi* are facultative intracellular within what cell type?

**Macrophages**

*Shigella spp.* are gram-\_\_\_\_\_\_\_\_ \_\_\_\_\_\_.

*Shigella spp.* are gram-**negative** **bacilli** (enteric tract).

*Shigella spp.* bacteria form _________ colonies on Hektoen enteric agar (HE) (differentiating them from *Salmonella spp.*, which form _________ colonies on HE).

*Shigella spp.* bacteria form **green** colonies on Hektoen enteric agar (HE) (differentiating them from *Salmonella spp.*, which form **black** colonies on HE).

**True/False**. *Shigella spp.* are motile, facultative intracellular organisms.

**False**. *Shigella spp.* are ***immotile***, facultative intracellular organisms.

*Shigella spp.* are acid-\_\_\_\_\_\_\_.

*Shigella spp.* are acid-**stable** (as opposed to *Salmonella spp.*, which are acid-labile).

Which requires a lower inoculum to cause infection, *Shigella spp.* or *Salmonella spp.*?

***Shigella spp.*** (acid-resistant; as opposed to *Salmonella spp.*, which are acid-labile)

*Shigella spp.* traverse the gut epithelial barrier by entering what cell type (and where?)?

**M cells** (in Peyer's patches)

After invading gut M cells, how do *Shigella spp.* move about intracellularly?

**Actin rockets** | (from M cell degraded cytoskeleton)

What can characteristically be found in the diarrhea caused by *Shigella spp.* infection?

**Blood**; **leukocytes** (predominantly neutrophils)

Which of the following uses a type III secretion system that delivers effector proteins directly into host cells? ## Footnote * Salmonella spp.* * Shigella spp.*

**Both**

The Shiga toxin (produced by *Shigella _dysenteriae_*) inactivates what in host cells?

The **60s** ribosomal subunit

What organism produces a Shiga-like toxin that is virtually identical to the Shiga toxin produced by *Shigella _dysenteriae_*?

E. coli

**True/False**. *Shigella spp.* cause an inflammatory gastroenteritis.

**True**. *Shigella spp.* cause an inflammatory gastroenteritis.

*Shigella* strains that produce Shiga-toxin (e.g. *Shigella dysenteriae*) can cause what severe syndrome that most commonly affects young children?

Hemolytic uremic syndrome

**True/False**. *Salmonella spp.* can lead to hemolytic uremic syndrome in young children.

**False**. ***Shigella** spp.* can lead to hemolytic uremic syndrome in young children.

The main causal factor for hemolytic uremic syndrome caused by *Shigella dysenteriae* is binding of Shiga-toxin to __________ cells in the \_\_\_\_\_\_\_\_\_\_\_, leading to platelet adherence and aggregation → **thrombocytopenia**, microangiopathic **hemolytic** **anemia**, and **acute** **kidney** **injury**.

The main causal factor for hemolytic uremic syndrome caused by *Shigella dysenteriae* is binding of Shiga-toxin to **_endothelial_** cells in the **_glomerulus_**, leading to platelet adherence and aggregation → **thrombocytopenia**, microangiopathic **hemolytic** **anemia**, and **acute kidney injury**.

The main causal factor for hemolytic uremic syndrome caused by *Shigella dysenteriae* is binding of Shiga-toxin to **_endothelial_** cells in the **_glomerulus_**, leading to platelet adherence and aggregation → \_\_\_\_\_\_\_\_\_\_, microangiopathic __________ **anemia**, and **acute** __________ **injury**.

The main causal factor for hemolytic uremic syndrome caused by *Shigella dysenteriae* is binding of Shiga-toxin to **endothelial** cells in the **glomerulus**, leading to platelet adherence and aggregation → **_thrombocytopenia_**, microangiopathic **_hemolytic_** **anemia**, and **acute _kidney_ injury**.

What age group is most likely to be affected by hemolytic uremic syndrome as a result of the Shiga-toxin produced by *Shigella dysenteriae*?

Young children

*Escherchia coli* are gram-\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_.

*Escherchia coli* are gram-**negative** **bacilli**.

*Escherichia coli* are \_\_\_\_\_\_\_\_\_-fermenting, meaning they form _____ colonies on MacConkey agar.

*Escherichia coli* are **lactose**-fermenting, meaning they form **pink** colonies on MacConkey agar.

Are *Escherichia coli* encapsulated?

Yes

The ___ antigen is unique to the *Escherichia coli* capsule.

The **K1** antigen is unique to the *Escherichia coli* capsule.

*Escherichia coli* form green colonies on what agar type?

EBM (eosin methylene blue)

*Escherichia coli* are \_\_\_\_\_\_\_\_\_\_-positive.

*Escherichia coli* are **catalase**-positive.

* Escherichia coli* __________ allow the *E. coli* to colonize the urinary tract. * E. coli* are the #\_\_\_ most common cause of UTIs.

* Escherichia coli* **fimbriae** allow the *E. coli* to colonize the urinary tract. * E. coli* are the #**1** most common cause of UTIs (accounting for ~80% of UTIs).

*Escherichia coli* is the leading cause of both _______ and also of gram-negative \_\_\_\_\_\_\_\_.

*Escherichia coli* is the leading cause of both **UTIs** and also of gram-negative **sepsis**.

Only *Escherichia coli* that possess the K1 antigen on their capsules can cause what presentation?

Neonatal meningitis

How is enterohemorrhagic *Escherichia coli* (EHEC) transmitted?

Ingestion of undercooked meats

What strain of enterohemorrhagic *Escherichia coli* (EHEC) is known for its ability to secrete \_\_\_\_\_\_-like toxin, thus potentially causing bloody diarrhea and hemolytic uremic syndrome? \_\_\_\_\_\_\_\_\_\_\_

What strain of enterohemorrhagic *Escherichia coli* (EHEC) is known for its ability to secrete **Shiga**-like toxin, thus potentially causing bloody diarrhea and hemolytic uremic syndrome? ## Footnote ***Escherichia coli O157:H7***

*Escherichia coli* O157:H7 can be differentiated from other strains of *E. coli* by its _________ (ability/inability) to ferment sorbitol.

*Escherichia coli* O157:H7 can be differentiated from other strains of *E. coli* by its **inability** to ferment sorbitol.

Which infectious agent is responsible for "Montezuma's revenge," also known as, "traveler's diarrhea"?

Enterotoxigenic *Escherichia coli* (ETEC)

Which form of *Escherichia coli* is often contracted while traveling and presents as watery diarrhea, abdominal cramping, nausea, and vomiting?

Enterotoxigenic *Escherichia coli* (ETEC)

Entero\_\_\_\_\_\_\_\_\_ *Escherichia coli* causes bloody diarrhea. Entero\_\_\_\_\_\_\_\_\_ *Escherichia coli* causes watery diarrhea.

Entero**hemorrhagic** *Escherichia coli* (EHEC) causes bloody diarrhea. Entero**toxigenic** *Escherichia coli* (ETEC) causes watery diarrhea.

Enterotoxigenic *Escherichia coli* (ETEC) produces two main toxins. The heat-_labile_ toxin increases intracellular \_\_\_\_\_\_\_\_. The heat-_stable_ toxin increases intracellular \_\_\_\_\_\_\_\_.

Enterotoxigenic *Escherichia coli* (ETEC) produces two main toxins. The heat-_labile_ toxin increases intracellular **cAMP**. The heat-_stable_ toxin increases intracellular **cGMP**. (Note: both toxins contribute to the watery diarrhea.)

Enterotoxigenic *Escherichia coli* (ETEC) produces two main toxins. The heat-\_\_\_\_\_\_ toxin increases intracellular **cGMP**. The heat-\_\_\_\_\_\_ toxin increases intracellular **cAMP**.

Enterotoxigenic *Escherichia coli* (ETEC) produces two main toxins. The heat-**_stable_** toxin increases intracellular **cGMP**. The heat-**_labile_** toxin increases intracellular **cAMP**. (Note: both toxins contribute to the watery diarrhea.)

*Yersinia enterocolitica* are gram-\_\_\_\_\_\_\_\_\_ _______ that ______ (are/are not) encapsulated.

*Yersinia enterocolitica* are gram-**negative** **bacilli** that **are** encapsulated.

*Yersinia pestis* are gram-\_\_\_\_\_\_\_\_\_ _______ that ______ (are/are not) encapsulated.

*Yersinia pestis* are gram-**negative** **bacilli** that **are** encapsulated.

*Yersinia enterocolitica* is primarily transmitted via what modes? What demographic is most at-risk?

**Pet feces**, contaminated **dairy** products; **children** (also associated with daycare centers)

The optimal temperature for *Yersinia enterocolitica* is \_\_\_°C. The optimal temperature for *Yersinia pestis* is \_\_\_°C.

The optimal temperature for *Yersinia enterocolitica* is **25**°C. The optimal temperature for *Yersinia pestis* is **30**°C. _NOTE: these are relatively cold conditions._

*Yersinia spp.* exhibit a characteristic _________ staining on microscopy.

*Yersinia spp.* exhibit a characteristic **bipolar** ('safety pin') staining on microscopy.

*Yersinia enterocolitica* can cause ___________ diarrhea.

*Yersinia enterocolitica* can cause **bloody** diarrhea.

A 6 year old male presents with pain in his right lower quadrant. His history is positive for a recent case of bloody diarrhea. What infectious agent could be mimicking appendicitis in this case? (Pseudoappendicitis)

*Yersinia enterocolitica*

What is the natural reservoir for *Yersinia pestis*? Humans are infected via what vector?

**Rodents** (e.g. prairie dogs); **flea** transmission

Intensely painful and swollen lymph nodes with overlying erythema (\_\_\_\_\_\_\_\_) are characteristic of ________ \_\_\_\_\_\_\_\_ infection.

Intensely painful and swollen lymph nodes with overlying erythema (**buboes**) are characteristic of ***Yersinia** **pestis*** infection.

Disseminated *Yersinia pestis* infection can lead to tissue ________ and cutaneous hemorrhage, \_\_\_\_\_\_, ______ shock, and multiple organ dysfunction syndrome.

Disseminated *Yersinia pestis* infection can lead to tissue **necrosis** and cutaneous hemorrhage, **DIC**, **septic** shock, and multiple organ dysfunction syndrome.

*Yersinia spp.* bacteria possess a type ___ secretion system that delivers effector proteins directly into host cells, such as Yersinia outer proteins (\_\_\_\_).

*Yersinia spp.* bacteria possess a type **III** secretion system that delivers effector proteins directly into host cells, such as Yersinia outer proteins (**Yops**).

How are *Yersinia spp.* infections treated?

**Aminoglycosides** (e.g. streptomycin); **tetracyclines** (e.g. doxycycline)

There is a ________ vaccine for innoculations against Yersinia \_\_\_\_\_\_\_\_, although it is not routinely given in the U.S.

There is a **killed** vaccine for innoculations against *Yersinia **pestis***, although it is not routinely given in the U.S.

*Campylobacter jejuni* are gram-\_\_\_\_\_\_\_\_\_, ______ bacilli.

*Campylobacter jejuni* are gram-**negative**, **curved** bacilli.

*Campylobacter jejuni* is a thermo\_\_\_\_\_ (-philic/-phobic) bacteria that grows at \_\_\_°C.

*Campylobacter jejuni* is a thermo**philic** bacteria that grows at **42**°C.

**True/False**. *Campylobacter jejuni* is transmitted to humans via mosquitoes. Animals such as poultry, cattle, sheep, and dogs are common reservoirs.

**False**. *Campylobacter jejuni* is transmitted to humans via the **fecal-oral route**. Animals such as poultry, cattle, sheep, and dogs are common reservoirs (it lives in the animals' GI tracts).

*Campylobacter jejuni* infection typically present with ______ \_\_\_\_\_\_\_. The bacilli are invasive and able to penetrate the intestinal epithelium, sometimes leading to \_\_\_\_\_\_\_\_\_\_.

*Campylobacter jejuni* typically present as a **bloody** **diarrhea**. The bacilli are invasive and able to penetrate the intestinal epithelium, sometimes leading to **bacteremia**.

*Campylobacter jejuni* are \_\_\_\_\_\_\_\_\_-positive.

*Campylobacter jejuni* are **oxidase**-positive.

Infection with what curved rod is associated with reactive (Reiter's) arthritis?

*Campylobacter jejuni*

Guillain-Barré syndrome is characterized by a(n) ___________ (ascending/descending) paralysis developed after infection with _________ \_\_\_\_\_\_\_\_\_.

Guillain-Barré syndrome is characterized by an **ascending** paralysis developed after infection with ***Campylobacter jejuni***.

A patient presents with bilateral thigh weakness that began a short time ago in the feet and has since moved up the leg. Ankle and knee reflexes are dimished. The only medical history is a somewhat recent case of bloody diarrhea. What is the diagnosis?

Guillain-Barré syndrome (following *Campylobacter jejuni* infection)

*Vibrio spp.* are gram-\_\_\_\_\_\_\_\_\_\_, _______ bacilli.

*Vibrio spp.* are gram-**negative**, **curved** bacilli.

*Vibrio cholerae* (the causal agent for cholera) is endemic in \_\_\_\_\_\_-\_\_\_\_\_\_\_\_ countries.

*Vibrio cholerae* is endemic in **low**-**income** countries *(outbreaks occur most commonly in southern Asia, Latin America, and Africa)*.

*Vibrio cholerae* cause \_\_\_\_\_\_\_, _______ diarrhea in those infected. This may be referred to as '\_\_\_\_\_\_-\_\_\_\_\_\_' stools.

*Vibrio cholerae* cause **profuse**, **watery** diarrhea in those infected. This may be referred to as '**rice**-**water**' stools.

How is *Vibrio cholerae* transmitted?

The fecal-oral route

The _________ of *Vibrio cholerae* allow the bacteria to attach to (but not invade) the intestinal mucosa and establish infection.

The **fimbriae** of *Vibrio cholerae* allow the bacteria to attach to (but not invade) the intestinal mucosa and establish infection.

Cholera toxin (produced by *Vibrio cholerae*) activates ____ subunits, thus increasing intracellular _______ in enterocytes and subsequent Na⁺ and Cl^- \_\_\_\_\_\_\_.

Cholera toxin (produced by *Vibrio cholerae*) activates **G_S** subunits, thus increasing intracellular **cAMP** in enterocytes and subsequent Na⁺ and Cl^- **efflux** (thus producing watery diarrhea).

**True/False**. Cholera toxin inactivates the G_i subunit, thus increasing adenylyl cyclase activity.

**False**. Cholera toxin ***activates*** the G***_S*** subunit, thus increasing adenylyl cyclase activity.

What is the preferred treatment for *Vibrio cholerae* treatment?

Oral rehydration

*Vibrio cholerae* is acid-\_\_\_\_\_\_\_ and prefers to grow on _______ agar.

*Vibrio cholerae* is acid-***labile*** and prefers to grow on ***alkaline*** agar. 'BASE cAMP'

*Vibrio cholerae* are acid-labile. What does this indicate about the concentration needed to cause illness in an individual?

It is **high** (many of the bacteria will die in the acidic gastric conditions)

*Vibrio spp.* are \_\_\_\_\_\_\_\_\_-positive.

*Vibrio spp.* are **oxidase**-positive.

*Vibrio parahaemolyticus* and *Vibrio vulnificus* infections are associated with consumption of raw \_\_\_\_\_\_\_.

*Vibrio parahaemolyticus* and *Vibrio vulnificus* infections are associated with consumption of raw **oysters**.

*Helicobacter pylori* are gram-\_\_\_\_\_\_\_\_\_\_, curved \_\_\_\_\_\_\_.

*Helicobacter pylori* are gram-**negative**, curved **bacilli**.

Are *Helicobacter pylori* encapsulated? Are *Helicobacter pylori* motile?

No; yes

*Helicobacter pylori* are \_\_\_\_\_\_\_\_\_\_\_-positive and \_\_\_\_\_\_\_\_\_\_\_-positive.

*Helicobacter pylori* are **urease**-positive and **oxidase**-positive.

~\_\_\_% of all duodenal ulcers are associated with *Helicobacter pylori* infection.

~**90**% of all duodenal ulcers are associated with *Helicobacter pylori* infection.

Urease converts urea into _________ and \_\_\_\_\_\_\_\_\_. This has an _________ (alkalizing/acidifying) effect.

Urease converts urea into **NH₃** and **CO₂**. This has an **alkalizing** effect.

*Helicobacter pylori* predispose those infected to what two malignancies?

1. Gastric adenocarcinoma 2. MALToma (a lymphoma)

What are the components of the 'triple therapy' used to treat *Helicobacter pylori* infection? ## Footnote **1. ______ \_\_\_\_\_\_ inhibitor** **2. \_\_\_\_\_\_\_\_\_\_/metronidazole** **3. ___________ (a macrolide)**

What are the components of the 'triple therapy' used to treat *Helicobacter pylori* infection? 1. **Proton pump** inhibitor 2. **Amoxicillin**/metronidazole 3. **Clarithromycin** (a macrolide)

Which three bacilli are described as gram-negative, comma-shaped rods? These are all \_\_\_\_\_\_\_\_\_-positive.

***Vibrio cholerae***, ***Campylobacter jejuni***, ***Helicobacter pylori*** These are all **oxidase**-positive.

*Proteus mirabilis* are gram-\_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_.

*Proteus mirabilis* are gram-**negative** **bacilli**.

When plated, *Proteus mirabilis* exhibit what?

Swarming motility

*Proteus mirabilis* are sometimes seen in **UTIs**. These organisms can cause __________ \_\_\_\_\_\_\_\_\_ in affected patients because they are \_\_\_\_\_\_\_\_\_\_-positive.

*Proteus mirabilis* are sometimes seen in **UTIs**. These organisms can cause **_staghorn calculi_** in affected patients because they are **_urease_**-positive.

*Proteus mirabilis* are sometimes seen in \_\_\_\_. These organisms can cause __________ **calculi** in affected patients because they are \_\_\_\_\_\_\_\_\_\_-positive.

*Proteus mirabilis* are sometimes seen in **_UTIs_**. These organisms can cause **_staghorn_ calculi** in affected patients because they are **_urease_**-positive.

Staghorn calculi are composed of _________ \_\_\_\_\_\_\_\_\_ _________ (chemical makeup). These stones are precipitated by __________ (acidic/alkaline) conditions in the urinary tract.

Staghorn calculi are composed of **magnesium** **ammonium** **phosphate**. These stones are precipitated by **alkaline** conditions in the urinary tract.

What feature of *Proteus mirabilis* causes an increase in urinary tract pH? What effect does this have?

*Proteus mirabilis* are **urease-positive**. Increased risk of **staghorn (struvite) calculi**

What type of infection does *Proteus mirabilis* cause? It is described as having what type of odor?

UTI; 'fishy'

How are UTIs caused by *Proteus mirabilis* treated?

Sulfonamides

A 25-year-old man presents to the emergency room for RLQ pain. He was found to have perforated appendicitis and was immediately taken to the operating room for emergent laparoscopic appendectomy. Due to the complexity of the case, the operation was converted to an open appendectomy. Post-operatively, he was put on a 7-day course of clindamycin and returned home. Two days later, he returned to the emergency room for diffuse abdominal pain. A computed tomography (CT) of his abdomen shows a fluid collection at the site of the appendix. ## Footnote **What infectious agent is likely involved?**

*Bacteroides fragilis*

What are the Gram state and oxygen need of *Bacteroides fragilis*?

Gram-negative; anaerobe

**True/False**. *Bacteroides fragilis* is only present in the body in cases of infection.

**False**. *B. fragilis* is part of the bacterial flora of the mucous membranes including the GI tract, mouth, and genitals.

What gram-negative anaerobe is known for causing abscesses at any endogenous site, including central nervous system (CNS), head and neck, abdomen, and pelvis?

*Bacteroides fragilis*

What two medications are commonly used against the intracorporeal abcesses created by *Bacteroides fragilis*?

Metronidazole; clindamycin

A 36-year-old male suffered a GSW to the abdomen that required an emergent exploratory laparotomy to repair and resect damaged portions of the bowel. Four days later, the patient reports increased generalized abdominal pain. His vital signs are as follows: T 38.5, HR 110, BP 110/60, RR 18, SpO2 96%. Physical exam reveals extreme tenderness to palpation of the abdomen as well as rebound tenderness, worse in the bilateral lower quadrants. The abdomen is mildly distended with guarding and decreased bowel sounds. The surgical and bullet-entrance wounds appear intact without any evidence of leakage/drainage, erythema, or warmth. Initial lab-work shows an elevated white blood cell count of 17.1 x 10^9 cells/L. A CT scan of the abdomen shows a 4 cm abscess in the left lower quadrant. **Which of the following organisms is the most likely cause of this patient's current presentation?** ## Footnote * Pseudomonas aeruginosa* * Salmonella enteritidis* * Bacteroides fragilis* * Enterococcus species* * Streptococcus bovis*

*Bacteroides fragilis*

Intraabdominal bacterial infections are typically polymicrobial, with _____________ and _____________ being the two most common organisms.

Intraabdominal bacterial infections are typically polymicrobial, with ***_Bacteroides fragilis_*** and ***_Escherichia coli_*** being the two most common organisms.

Gram-Negative Bacilli - Enteric Tract Flashcards

(136 cards)