(F) Lesson 13: Non-fermenters and Miscellaneous Gram-Negative Bacilli (Part 2) Flashcards
(62 cards)
1
Q
General Characteristics
- 12 species: 2 species most commonly seen in clinical specimens
- Environment: soil, water, and food stuffs
- Hospital environment: ventilators, humidifiers, catheters, and other devices
- Insignificant or as contaminants when isolated from nonsterile sites
- Increased isolates indicate resistance
- Are opportunists (#2 in nosocomial infections)
A
Acinetobacter spp.
2
Q
- Formerly Herella vaginocola
- Glucose-oxidizing nonhemolytic strain
- Has high potential for resistance, like P. aeruginosa
- Causes ventilator-associated pneumonia and sepsis that have high mortality rates
- Causes UTIs, pneumonia, tracheobronchitis, or both, endocarditis, septicemia, meningitis, and cellulitis, endophthalmitis, conjunctivitis, and corneal ulcerations
A
Acinetobacter baumannii
3
Q
Acinetobacter baumanii
Resistant/Susceptible?
- Penicillin
- First and second-generation cephalosporins
- Fluoroquinolones
A
Resistant
4
Q
Acinetobacter baumanii
Resistant/Susceptible?
- Aminoglycosides
- B-lactam + B-lactamase inhibitor combinations
A
Susceptible
5
Q
Acinetobacter baumanii
- Contain carbapenemases
- Susceptible to colistin and tigecycline
A
CRAB or Carbapenem-Resistant Acinetobacter baumanii
6
Q
- Formerly Mima polymorpha
- Glucose-negative, nonhemolytic strain
- Less virulent and less severe
- Susceptible to most antibiotics
A
Acinetobacter lwoffii
7
Q
- Strictly aerobic
- G(-) coccobacilli or even G(-) cocci from blood culture
- (+) catalase,
- (-) oxidase, non-motile
- Can resist decolorization and retain crystal violet, leading to mis-ID
A
Acinetobacter spp.
8
Q
Acinetobacter spp.
Saccharolytic in MAC (purplish)?
A
Acinetobacter baumannii
9
Q
Acinetobacter spp.
Asaccharolytic in MAC?
A
Acinetobacter lwoffii
10
Q
Clinical Infections
- 3rd most common non-fermentative, G(-) bacillus isolated in the clinical laboratory.
- Former genus: Pseudomonas → Xanthomonas (plant pathogen) → Stenotrophomonas
- Usually found as a saprophyte or a colonizer
- Environment: water, sewage, and plant materials
- Hospital environment: contaminating blood drawing equipment, disinfectants, transducers, and other equipment
A
Stenotrophomonas maltophilia
11
Q
- Risk factors: immunosuppression, hospitalization, especially in an ICU, and the presence of a central venous catheter.
- Endocarditis, especially in a setting of prior intravenous (IV) drug abuse or heart surgery, wound infections, including cellulitis and ecthyma gangrenosum, bacteremia and, rarely; meningitis and UTIs
A
Clinical Infection of Stenotrophomonas maltophilia
12
Q
What is the rank of Stenotrophomas maltophilia in lower respiratory tract infections in CF patients?
A
Third
13
Q
- G(-) bacilli
- (+) catalase, DNase, esculin and gelatin hydrolysis, and lysine decarboxylase
- (-) oxidase
- Colonies: bluish on MAC, ammonia-like odor
A
Stenotrophomonas maltophilia
14
Q
Stenotrophomonas maltophilia
Resistant/Susceptible?
- Cephalosporins
- Penicillins
- Carbapenems
- Aminoglycosides
A
Resistant
15
Q
Stenotrophomonas maltophilia
Resistant/Susceptibility?
- Trimethoprim-sulfamethoxazole (SXT) (DOC)
- Ticarcillin-clavulanate
- Fluoroquinolone levofloxacin
- Tetracyclines, including tigecycline
A
Susceptible
16
Q
- Mortality in patients with S. maltophilia infections are associated with inappropriate antimicrobial treatment
- They were initially given ____
A
Carbapenem
17
Q
Stenotrophomonas maltophilia
- ____ and ____ can be performed
A
Broth microdilution and Etest or agar dilution
18
Q
- All have been isolated from humans
- Former member of the Pseudomonas
- From irrigation fluids, anesthetics, nebulizers, detergents, and disinfectants.
- Part of the non-fluorescent group
- Contains plant pathogens that have arisen as opportunistic organisms, associated with pneumonia in patients with CF or chronic granulomatous disease
- Colonies: non-wrinkled
A
Burkholderia Cepacia Complex
19
Q
- (+) oxidase, glucose, maltose, lactose, and mannitol, lysine decarboxylase (LDC) and ONPG, motile (polar tufts of flagella)
- (-) ornithine decarboxylase (ODC), nitrate → nitrite
- (+) MAC
A
Burkholderia spp.
20
Q
- Increased recovery in ____ that reduce growth of P. aeruginosa and other G(-) bacilli
A
Selective media with antimicrobials
21
Q
- Most effective
- Selective agar has additional antibiotics to inhibit the growth of normal flora
A
BCSA (Burkholderia cepacia selective agar)
22
Q
- Crystal violet, bile salts, polymyxin B, ticarcillin, phenol red
A
Pseudomonas cepacia
23
Q
What rank is Burkholderia spp. in terms of causing of pneumonia in patients with CF or chronic granulomatous disease?
A
Second
24
Q
Identify the organism.
- Endocarditis (specifically in IV drug abusers)
- Pneumonitis, UTIs, osteomyelitis, dermatitis
- Other wound infections resulting from the use of contaminated water
A
Burkholderia spp.
25
# Burkholderia spp.
**Resistant/Susceptible?**
* Aminoglycosides
* Polymyxins
* β-lactam antibiotics
Resistant
26
# Burkholderia spp.
**Resistant/Susceptible?**
* Chloramphenicol
* Ceftazidime
* Piperacillin
* Minocylcine
* Some fluoroquinolones
* SXT
* Carbapenems (variable)
Susceptible
27
* Usually in very **immunocompromised patients** because it is a plant pathogen
* Resembles **B. cepacia complex** (molecular tools for confirmation)
* Differentiate from P. aeruginosa using oxidase test
* **Clinical Infections:** In patients with CF (lung transplant) and CGD, immunocompromised patients
Burkholderia gladioli
28
* **Colonies**: yellow
* (+) motile (one or two polar flagella), catalase, urease, glucose, mannitol, MAC
* (-) decarboxylase, oxidase (some are weakly positive)
Burkholderia gladioli
29
# Burkholderia gladioli
**Resistant/Susceptible?**
* Polymyxin B
* Aztreonam
* Cephalosporins
Resistant
30
# Burkholderia gladioli
**Resistant/Susceptible?**
* Aminoglycosides
* Carbapenems
* Ciprofloxacin
* SXT
Susceptible
31
T or F: B. gladioli isolates are **more susceptible** to antimicrobials than B. cepacia.
T
32
* Potential bioterrorism agent
* Can be weaponized
* Since it causes a respiratory infection, it spreads easily
* A zoonotic disease
Burkholderia mallei
33
# Identify the organisms.
* **Rare in humans:** severe local suppurative or acute pulmonary infections
* e.g. Glanders Disease
Burkholderia mallei
34
* G(-) coccobacillus
* **Colonies**: non-pigmented in 2 days, non-motile
* Only **non-fermenter** that is non-pigmented
* (+) MAC, oxidase (variable), glucose, nitrate to nitrite, ADH
* (-) decarboxylase, oxidase (some are weakly positive), non motile
Burkholderia mallei
35
# Burkholderia mallei
A respiratory tract zoonosis primarily affecting livestock such as horses, mules, and donkeys
Glanders Disease
36
# Burkholderia mallei
The only drug resistant with Burkholderia mallei?
Polymyxin B
37
* CLSI recommends ____ with ____ to consider
Broth microdilution with Brucella broth
38
* Also called **Vietnamese Time Bomb**
* Potential agents of bioterrorism
* Found in water and muddy soils in Southeast Asia (including Vietnam and Thailand), Northern Australia, and Mexico
Burkholderia pseudomallei
39
* Also produces a **respiratory infection**
* Like rabies, the incubation period may be prolonged, with reactivation occurring long after exposure
* Unusual for bacteria which usually takes only weeks before the onset of an infection
* Its latency is common among viruses
Burkholderia pseudomallei
40
# Identify the organism.
* Meliodosis
* Overwhelming septicemia
* Local infections such as orbital cellulitis, dacryocystitis, and draining abscesses, sometimes with with pneumonia
Burkholderia pseudomallei
41
# Burkholderia pseudomallei
Aggressive, granulomatous, pulmonary disease
By ingestion, inhalation, or inoculation of the organisms, with metastatic abscess formation in lungs and other viscera
Meliodosis
42
* (+) Bipolar staining
* **Colonies**: wrinkled
* **MALDI-TOF** for rapid confirmation
* **Multiplex polymerase chain reaction (PCR) assays** for the identification
Burkholderia pseudomallei
43
* Selective for B. pseudomallei
* Contains colistin (antibiotic)
* Results in deep pink colonies from the absorption of neutral red from the medium + **earthy odor**
Ashdown Medium
44
# Burkholderia pseudomallei
**Resistant/Susceptible?**
* SXT
* Chloramphenicol
* Tetracycline
* Semisynthetic
* Penicillin
* Ceftazidime
Susceptible
45
* Grouped due to similar biochemical reactions
* An **unusual** group of non-fermenters, though they are **obligate aerobes**, they are **susceptible to penicillin**
* G(-) coccobacillary to bacillary
* (+) oxidase,
* (-) motility, asaccharolytic
* Are opportunists that reside on the mucous membranes of humans and lower animals
* Rarely cause disease in humans, except **M. catarrhalis**
Moraxella, Oligella, and Psychrobacter
46
* Resistance is due to continued exposure
* Resistance to ____ is found in the plasmid that can be shared via pili
Penicillin
47
What are the most commonly encountered species of Moraxella?
* M. catarrhalis
* M. nonliquefaciens
* M. lacunata
* M. osloensis
* M. lincolnii
* M. atlantae
48
# Moraxella spp.
Reclassified as Psychrobacter phenylpyruvicus
M. phenylpyruvica
49
* Most frequent isolate in the genus Moraxella from clinical specimens
* Especially from the ear and respiratory specimens
* Resembles the Neisseria due to G(-) coccal morphology
Moraxella catarrhalis
50
* Second most commonly isolated member of the genus.
* Can cause rare cases of bacteremia, keratitis, and endophthalmitis
* Normal biota in the respiratory tract
* Morphologically and biochemically similar to M. osloensis
Moraxella nonliquefaciens
51
# Osloensis and Nonliquefaciens?
Found in the genitourinary tract?
Moraxella osloensis
52
# Osloensis and Nonliquefaciens?
Found in the respiratory tract?
Moraxella nonliquefaciens
53
* Its 2 species can be differentiated by motility
* Use a **Sulfide, Indole, Motility (SIM)** medium to observe motility
Oligella spp.
54
# Oligella spp.
The motile species of Oligella
Oligella ureolytica
55
# Oligella spp.
The non-motile species of Oligella
Oligella urethralis
56
* (+) MAC, phenylalanine deaminase (PDA), oxidase, and nitrate to nitrite w/ gas formation
* (-) non-oxidative, non-motile
* Commensal of the **genitourinary tract**
* Report of a case of infectious arthritis that was mistaken for gonococcal arthritis
* **Susceptible:** penicillin
Oligella urethralis
57
* (+) MAC, phenylalanine deaminase (PDA), oxidase and nitrate to nitrite w/ gas formation, motile (peritrichous flagella)
* (-) non-oxidative
* **Bacteremia** in a patient with AIDS and in an 18-month-old child with pneumonia
* **Susceptible**: penicillin
Oligella ureolytica
58
* Are weird organisms since these grow well at low temperatures, 5-250C, rarely at 35 deg C
* It thrives in high temperatures
Psychrobacter
59
* **Psychrotrophic:** optimal growth at 20°C (5-25°C)
* **Modified Thayer-Martin Medium**
* Isolated from fish, processed meat, and poultry.
* (+) oxidase, oxidative, nitrate to nitrite
* (-) non-motile
* Not susceptible to penicillin, but susceptible to other antimicrobial agents
Psychroabcter immobilis
60
# Psychrobacter immobilis
* Modified by adding Tween 80
* Growth has odor of roses like phenyl ethyl alcohol, isolates resemble Moraxella
* Commonly used for isolating Neisseria spp.
Modified Thayer-Martin
61
# Associate the organism with the odor.
1. Pseudomonas aeruginosa
2. Stenotrophomonas maltophilia
3. Burkholderia pseudomallei
A. Ammonia-like
B. Earthy odor
C. Grape-like
1. C
2. A
3. B
62
* Isolated from urine, blood, CSF, and the genitourinary tract
* (+) urease, phenylalanine deaminase (PDA)
Psychrobacter phenylpyruvicus
