L6 MHD: Pseudomonas/Gram - Rods

Question 1

What 6 gram negative Bacilli do not ferment glucose?

Answer 1

1. PSEUDOMONAS Aureginosa
2. Burkholderia pseudomallei
3. Burkholderia cepacia
4. Stenotrophomonas maltophilia
5. Elizabethkingia meningoseptica
6. Acinetobacter baumannii

Question 2

Glucose Non-Fermenting Bacilli:

1. Gram (+ or -)
2. Spores?
3. What 2 shapes?
4. Aerobe/anaerobe? Facultative/obligate?
5. Natural Habitat?

Answer 2

1. Gram negative
2. NOT spores
3. Rods or Coccobacilli
4. OBLIGATE AEROBES* (test)
   - good growth within 24hours
5. Water, soil, plans

** exist in nature (unlike Enterobacteriaciae which is part of normal gut flora)

Question 3

Pseudomonas Aeruginosa:

1. Aerobic/Anaerobic?
2. Rod or bacilli?
3. What is unique to polysaccharide?
4. What is on the cell surface?

Answer 3

1. Aerobic Gram negative rod
2. Motile with polar flagella
3. Mucoid polysaccharide slime layer
4. Pili on cell surface

Question 4

EPIDEMIOLOGY of P AERUGINOSA:

1. _____ organism
2. Grows in ?
3. What environment?
4. Specifically what type of areas?

Answer 4

1. ENVIRONMENTAL organism
2. Grows in unsterile water, medications, disinfectants
3. Hospital environment
4. Moist areas:

Sinks
Toilets
Cut flowers
Floor mops
equipment

** be especially weary in the case of immunosuppressed patients**
(do not bring fresh flowers, salads etc because they may contain Non-fermenters)

Question 5

P. aeruginosa is a _____pathogen

What 5 factors predispose to serious infections of P. Aeruginosa?

Answer 5

Oppotunistic

1. Burn patients**
   - lose barrier of defense
2. Cystic fibrosis patients
3. Patients with hematologic malignancies
4. Immunocompromised patients
5. Can be part of the microbial flora in hospitalized patients and ambulatory, immunocompromised hosts
   - Infections occur at any site where moisture tends to accumulate, indwelling catheres, trach sites, burns, external ear

Question 6

The following are examples of what:

1. Burn wounds
2. FOLLICULITIS
   - hot tubs, whirlpools, swimming pools, water slides
   - chlorine content may not be adequate to kill
   the bacteria
3. NAIL infections

Answer 6

Pseudomonas Skin infections

Question 7

Pseudomoas Pulmonary infection shows:

1. ________ colonization
2. What 3 main diseases?
3. Most common cause of ______

Answer 7

1. Asymptomatic
2. a) Cystic fibrosis, b)chronic lung disease
   c) Severe necrotizing bronchopneumonia
3. ventilator associated pneumonia (VAP)!!!!

** any question of a patient with ventilator = PSEUDOMONAS **

Question 8

What are some other common pseudomonas infections not associated with skin or lungs? (6)

Answer 8

1. Urinary tract infections
2. Ear infections
   - “swimmers ear”
   - Malignant external otitis
   - Chronic otitis media
3. Eye Infections
   pseudomonas is a
   contaminant in eye
   cosmetics
4. Bacteremia
   - Ecthyma gangrenosum
5. Endocarditis
   - IVDA and involves the tricuspid valve
6. Osteomyelitis

PSEUDDO
P - pneumonia
S- sepsis 
E - otitis Externa 
U - UTI
D - diabetes
D - Drug use
O - osteomyolitis

Question 9

What is Ecthyma Gangrenosum?

What is it associated with?

Which patients does it usually occur in?

Answer 9

1. Uncommon cutaneous infection
2. Bacteremic infection of P.Aeriginosa
3. Critically ill & IMMUNOCOMPROMISED

Question 10

What are the characteristics of Bactermia with Ecthyma Gangrenosum?

What does it evolve into?

How long would this take? (minimally)

Answer 10

1. Hemorrhagic pustules
2. Infarcted appearing areas w/ erythema
3. Evolve into NECROTIC ULCERS surrounded by erythema
4. **The transformation of an early lesion to a necrotic ulcer may occur in as little as 12 HOURS!!!

RAPID

Question 11

What is the pneumonic PSEUDDO stand for?

What does the AERiginosa clue you in on?

Answer 11

P = pneumonia
S = sepsis
E = otitis EXTERNA (swimmer's ear)
U = UTIs
D = drug use
D = diabetes
O = osteomyelitis 

AERiginosa = AEROBIC

** think pseudomonas in burn victims

• mucoid polysaccardie capsule may contribute to chronic pneumonia in cystic fibrosis patients due to BIOFILM formation

Question 12

What color is the agar plate as a result of culturing P. Aeriginosa?

Answer 12

GREEN CAN ONLY BE THERE IF PRODUCING BOTH PYOCYANIN & PYOVERADIN

• pyocyanin is a blue pigment
• also produces Pyoveradin (yellow light on media)

(blue + yellow) = GREEN ON AGAR PLATE

green only present if both pyocyanin & pyoveradin produced

Question 13

Describe the 4 main structural virulence factors of Pseudomonas aeruginosa.

Answer 13

1. Capsule
2. Pilli
3. LPS
4. Pyocyanin

Question 14

What are the 3 Toxins and Enzymes that contribute to the virulence factors.

Answer 14

1. Exotoxin A
2. Exoenzyme S
3. Elastase

Question 15

The following describes Exotoxin A or Exoenzyme S?

1. Correlates with virulence
2. Blocks protein synthesis much like diphtheria toxin (inhibits E2F)
3. Most likely contributes to DERMATONECROSIS in wounds and tissue damage in lungs

Answer 15

Exotoxin A

• EF2 ribosylated by toxin
  = INHIBITION of protein synthesis & cell death

Question 16

The following describes Exotoxin A or Exoenzyme S?

1. ADP-ribosylating toxin
2. Epithelial cell damage
   facilitates bacterial spread, tissue invasion and necrosis

Answer 16

Exoenzyme S

Question 17

What toxin is specifically responsible for tissue destruction & hemorrhagic lesions?

What 2 enzymes are specifically responsible?

How does this toxin affect the innate & adaptive immune response? (2)

Answer 17

1. ELASTASE
   - produces lung parenchymal damage
2. LasA & LasB act synergistically to degrade ELASTIN
3. • Degrades complement components
   • inhibits neutrophil chemotaxis and function

Question 18

What kind of a media does P. Aeriginosa grow on?

- describe the way the colonies look

Answer 18

1. Blood & MacConkey agar producing SPREADY colonies with a metallic sheen

(alligator skin appearance)

Question 19

State the following for P.Aeriginosa (VERY IMPORTANT)

1. Glucose (fermenter or non)
2. Oxidase (+ or -)
3. Characteristic odor?
4. Produces ____ pigment
5. Grows at ____ temp
6. Obligate aerobe/anaerobe?

IT IS THE ONLY ORGANISM THAT PRODUCES _____

Answer 19

1. Glucose NON fermenter
2. Oxidase POSITIVE
3. Grape odor
4. produces PYOCYANIN & Pyoverdin
5. grows at 42 celsius (warm)
6. obligate AEROBE (air billow)

ONLY ORGANISM THAT PRODUCES PYOCYANIN!!

GRAM NEGATIVE ROD

-encapsulated!!!(thrives in aquativ envi/moist –> think of the tub from sketchy)

Question 20

What accounts for the MUCOID appearance of P. Aeruginosa?

Answer 20

1. Production of ALGINATE
   - all pseudomonas have a gene to produce alginate (normal pseudomonas as an inactive gene, and CF patients have conditions that are optimal for this gene and turn it “on”
   - high salt content
   - high humidity

Creates a mucoid colony which is difficult to resolve! Patients become chronically infected and eventually lung is destroyed and they need a lung transplant

Question 21

How are pseudomonas infections treated?

Why is this bacteria resistant to so many antibiotics?

What are fluroroquinolones used to treat specifically?

Answer 21

1. Combination therapy of
   - cell wall active agent
   - AMINOGLYCOSIDE

UREIDOPENICILLIN or CARBOXYPENICILLIN

2. Resistant due to changes in PORINS
   - block the porins

TREAT WITH:
- pipercillin + tazobactam

less common: ahminoglycosides (w/B-lactam antibiotics) + fluoroquinolones

USED FOR UTIS!

Question 22

A gram-negative rod grows as a colorless colony on a MacConkey agar plate. Further laboratory testing shows the organism is oxidase positive, does not ferment glucose, produces a sweet grape-like odor and grows at 420C. Which of the following clinical infections is most likely to be caused by this organism?

A. Ear infection after swimming in a fresh water lake

B. Melioidosis
Community acquired urinary tract infection

C. Community acquired pneumoniae

D. Gastroenteritis following ingestion of contaminated water

Answer 22

1 cause Pneumonia = STREP PNEUMONIA!!!

A. Ear infection after swimming in a fresh water lake

Melioidosis is an infectious disease caused by a gram-negative bacterium, Burkholderia pseudomallei, found in soil and water. It is of public health importance in endemic areas, particularly in Thailand and northern Australia.

Question 23

If an organism is OXIDASE positive, which group of bacteria is automatically eliminated?

Answer 23

ENTEROBACTERIACAE

Question 24

Burkholderia Pseudomallei

1. What do B. Mallei and B. Pseudomallei belong to?

Answer 24

1. A single genomospecies

• Originally named Pseudomonas
• Changed to Burkholderia in 1992

Question 25

Burkholderia Pseudomallei 1. Habitat? 2. Found primarily where? 3. What disease does it cause? 4. What is a unique feature of this bacteria?

Answer 25

1. Soil, water, vegetation of S.E. Asia, 20 north & south of equator 2. Primarily found in India, Thailand, Vietnam, northern Australia. Also endemic in China, Taiwan, Laos 3. CATEGORY B Biothreat "burholderia can HOLD you hostage"

Question 26

What is the treatment for Burkholderia Pseudomallei?

Answer 26

Ceftriaxone & vancomycin

Question 27

Describe the symptoms of the 3 types of MELIOIDOSIS associated with Burkholderia Pseudomallei. 1. Acute Disease 2. Subacute Disease 3. Chronic Disease

Answer 27

1. Acute - SEPTICEMIA with metastatic lesions (95% mortality if untreated( 2. Subacute * most common * TB LIKE PNEUMONIA w/ CEllulitis & Lymphangitis 3. Chronic Disease: - LOCALIZED CHRONIC CELLULITIS - treat with antibiotics before draining otherwise become BACTEREMIC

Question 28

Burkholderi Cepacia COMPLEX 1. Habitat? 2.

Answer 28

Habitat: - water sources - wet surfaces - detergent solutions - (grows in iodine & hexochluorofene soap)

Question 29

What bacteria is a major clinical problem in patients with the following: 1. CF 2. Chronic Granulomatous Disease 3. UTI 4. Septicemia 5. Other opportunistic infections & is a NON -LACTOSE FERMENTER

Answer 29

Burkholderia cepacia

Question 30

1. Cystic fibrosis is (autosomal dom/recessive)? | 2. What is it caused by?

Answer 30

1. AUTOSOMAL RECESSIVE - in caucasians 2. Mutation in CFTR transmembrane conductance regulator - Regulates components of sweat, digestive juices, mucus. - Persons without CF have two working copies of CFTR gene, only one is needed to prevent CF.

Question 31

Mutation in CFTR result in: 1. Defects in ____ immunity & decreased ____ levels. 2. Failure to do what? 3. Increased _____ in CF airway 4. Abnormal electrolyte transport resulting in _____ How does this abnormal electrolyte transport effect mucocilliary clearance?

Answer 31

1. defects in INNATE immunity including decreased NITRIC OXIDE levels 2. failure to internalize bacteria in bronchial epithelial cells 3. increased INFLAMMATION in CF airway 4. abnormal electrolyte transport causing THICK, DRY, STICKY mucus Abnormal mucus adversely effects mucocilliary clearance providing an ideal niche for CHRONIC lung infection

Question 32

85% of premature deaths in CF are due to ____ secondary to chronic lung infection.

Answer 32

1. Cardiopulmonary failure In US median life expectancy is 37 yrs. **Lung transplant is often necessary as CF worsens CF may be Dx by many different methods including newborn screening, sweat testing, and genetic testing.

Question 33

What is PULMONARY EXACERBATION? Result of this?

Answer 33

Cellular defect results in THICKENED viscous mucus layer in resp tract and impaired innate immunity - Results in impaired mucocillary transport and chronic infection with limited number of bacterial species Chronic infection leads to INTERMITTENT PULMONARY EXACERBATIOn

Question 34

What is Pulmonary Exacerbation characterized by? (3) 1. What is recruited? 2. What is released? 3. High levels of what?

Answer 34

1. Recruitment of neutrophils 2. Cytokine release 3. High level of neutrophil derived ELASTASES causing significant lung pathology

Question 35

What are the 3 main CF pathogens of CHRONIC LUNG DISEASE?

Answer 35

1. Staph Aureus 2. P. Auriginosa 3. B. Cepacia ALSO: 4. Aspergillus 5. Scedosporium 6. Mycobacterium abscessus AND RHINOVIRUS IS THE MOST COMMON VIRUS in CLD

Question 36

Burkholderia Cepacia Complex: 1. Glucose (fermenter or non? 2. Pigment? 3. Oxidase + or - ? KNOW THESE

Answer 36

1. Glucose NON - fermenter 2. YELLOW pigment 3. Slow oxidase positive - resistant to most antibiotics

Question 37

Stenotrophomonas Maltophilia WHat 5 opportunistic infections is it associated with?

Answer 37

First called Pseudomonas then Xanthomonas 1. Bacteremia 2. Pneumonia 3. Meningitis 4. Wound Infections 5. Urinary Tract Treatment complicated by resistance to many commonly used antibiotics

Question 38

What is the habitat of Stenotrophomonas maltophilia? (4) What is the most common? Area

Answer 38

1. Worldwide distribution 2. SOIL, WATER, animals, vegetation, crops 3. Not part of normal skin or GI flora (but can be recovered from almost any clinical site) 4. RESPIRATORY TRACT MOST COMMON

Question 39

Stenotrophomonas maltophilia 1. >95% of all clinical infections are ____ acquired 2. 2nd leading cause of what? 3. Hallmark is _______

Answer 39

1. Hospital acquired! 2. 2nd leading cause of gram-negative non-fermentative bacillary infections 3. Hallmark: LIFE - THREATENIN SYSTEMIC INFECTIONS in DEBILITATED PATIENTS (usually malignancy)

Question 40

Stenotrophomonas maltophilia 1. Shows good growth on ____ 2. Oxidase + or -? (TEST TEST TEST) 3. Similar to B. Cepacia in that its pigment is _____

Answer 40

1. BAP & MacConkey 2. Oxidase NEGATIVE - usually non-fermenters are oxidase negative like Enterobacteriacae, but so is S. Maltophila! 3. YELLOW pigment

Question 41

True or False: Stenotrophomonas Maltophilia is very resistant to beta lactam agents.

Answer 41

TRUE - Inherently resistant to beta lactam agents including imipenem and aminoglycosides

Question 42

What is the drug of choice for S. Maltophilia? What is the exception to this?

Answer 42

trimethoprim-sulfamethoxazole (SXT)” = BACTRAM 2. SULFA ALLERGY - do not use this instead use: ``` ticarcillin/clavulanate (discontinued - timentin), ceftazidime, levofloxacin, minocycline, tigecycline ```

Question 43

Which bacteria is often found in the following habitat: 1. Soil, water, plants food stuffs 2. Water systems & wet surfaces 3. Nocosomial outbreaks traced to BREAST PUMPS

Answer 43

Elizabethkingia meningoseptica ** REMEMBER Breast pumps = Elizabethkingia Meningoseptica

Question 44

What are the 5 bacteria that cause neonatal meningitis? | test

Answer 44

NEONATAL MENINGITIS 1. Ecoli 2. Citrobacter koseri 3. E.Meningoseptica 4. GROUP B strep (+) 5. Listeria (+)

Question 45

Elizabethkingia Meningoseptica 1. Pathogenic for _____ 2. Associated with what neonatal disease? 3. Where do epidemics occur? 4. Nocosomial outbreaks linked to _____ 5. May cause pneumonia in what type of adults?

Answer 45

1. PREMATURE infants 2. Neonatal Meningitis 3. Epidemics in NURSERIES 4. Breast pumps!!! 5. Immunocompromised adults are likely to get Elizabethkingia Meningoseptica

Question 46

Elizabethkingia Meningoseptica 1. Oxidase + or -? 2. Pigment on BAP? 3. Growth on MacConkey? * different from other gram -

Answer 46

1. Oxidase POSITIVE 2. Yellow pale pigment on BAP 3. INHIBITED ON MacConkey

Question 47

Elizabethkingia Meningoseptica 1. Susceptibility? 2. Resistant to? (2)

Answer 47

1. VERY RESISTANT 2. - resistant to beta lactam agents - aminoglycosides

Question 48

Drug of choice for Elizabethkingia Meningoseptica (4)

Answer 48

Drug of choice: 1. Minocycline 2. Rifampin 3. SXT 4. Quinolones

Question 49

Acinetobacter Baumannii Habitat? Most common organism carried on _____

Answer 49

1. Free living in water and soil 2. Isolated foods, hospital air, inanimate objects, numerous human sources 3. Most common gram-negative organism carried on skin of hospital personnel

Question 50

Acinetobacter Baumannii: 1. Low ____ but implicated in community acquired & nosocomial infections 2. Recovered from what human sources? (5) 3. Found to colonize 45% of inpatient_____

Answer 50

1. LOW VIRULENCE ``` 2. blood sputum urine feces vagina ``` 3. Found to colonize 45% of inpatient tracheostomy WHY? - tracheostomies need a lot of daily care most common org. on hands of hospital employees fortunately = LOW VIRULENCE (may just be colonized --> but no infection )

Question 51

Acinetobacter baumannii 1. Shape on gram stain? 2. Growth on BAP & MacConkey? 3. Oxidase + or - 4. Motile?

Answer 51

1. COCCOBACILLI on gram stain 2. GOOD growth on BAP and MacConkey (unlike E. meningoseptica ) 3. Oxidase NEGATIVE!!! 4. Non-motile

Question 52

What is Acinetobacter Baumannii commonly treated with? (5 total, 2 most important)

Answer 52

1. Imipenem 2. Meropenem ** broadest spectrum CARBEPENAMS** 3. Fluoroquinolone + amikacin or ceftazidime 4. Ampicillin-sulbactam 5. Colistin ***Resistance rates increasing If something is carbepenam resistant = RESISTANT TO EVERYTHING! (but fortunately A. Baumannii is LOW VIRULENCE!)

Question 53

A gram-negative rod was recovered from the CSF of a newborn with meningitis. It was an oxidase-positive, glucose non-fermenting rod, that failed to grow on MacConkey agar and was indole-positive. An epidemiologic investigation revealed that the mother was using a breast pump that belong to the hospital nursery and may have been the source of the causative agent. What is the likely agent of meningitis in this case. A. Elizabethkingia meningoseptica B. Citrobacter koseri C. E. coli D. Listeria monocytogenes E. Neisseria meningitidis

Answer 53

A. Elizabethkingia meningoseptica - BREAST PUMP