(F) Lesson 13: Non-fermenters and Miscellaneous Gram-Negative Bacilli (Part 2) Flashcards
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)
Acinetobacter spp.
- 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
Acinetobacter baumannii
Acinetobacter baumanii
Resistant/Susceptible?
- Penicillin
- First and second-generation cephalosporins
- Fluoroquinolones
Resistant
Acinetobacter baumanii
Resistant/Susceptible?
- Aminoglycosides
- B-lactam + B-lactamase inhibitor combinations
Susceptible
Acinetobacter baumanii
- Contain carbapenemases
- Susceptible to colistin and tigecycline
CRAB or Carbapenem-Resistant Acinetobacter baumanii
- Formerly Mima polymorpha
- Glucose-negative, nonhemolytic strain
- Less virulent and less severe
- Susceptible to most antibiotics
Acinetobacter lwoffii
- 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
Acinetobacter spp.
Acinetobacter spp.
Saccharolytic in MAC (purplish)?
Acinetobacter baumannii
Acinetobacter spp.
Asaccharolytic in MAC?
Acinetobacter lwoffii
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
Stenotrophomonas maltophilia
- 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
Clinical Infection of Stenotrophomonas maltophilia
What is the rank of Stenotrophomas maltophilia in lower respiratory tract infections in CF patients?
Third
- G(-) bacilli
- (+) catalase, DNase, esculin and gelatin hydrolysis, and lysine decarboxylase
- (-) oxidase
- Colonies: bluish on MAC, ammonia-like odor
Stenotrophomonas maltophilia
Stenotrophomonas maltophilia
Resistant/Susceptible?
- Cephalosporins
- Penicillins
- Carbapenems
- Aminoglycosides
Resistant
Stenotrophomonas maltophilia
Resistant/Susceptibility?
- Trimethoprim-sulfamethoxazole (SXT) (DOC)
- Ticarcillin-clavulanate
- Fluoroquinolone levofloxacin
- Tetracyclines, including tigecycline
Susceptible
- Mortality in patients with S. maltophilia infections are associated with inappropriate antimicrobial treatment
- They were initially given ____
Carbapenem
Stenotrophomonas maltophilia
- ____ and ____ can be performed
Broth microdilution and Etest or agar dilution
- 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
Burkholderia Cepacia Complex
- (+) oxidase, glucose, maltose, lactose, and mannitol, lysine decarboxylase (LDC) and ONPG, motile (polar tufts of flagella)
- (-) ornithine decarboxylase (ODC), nitrate → nitrite
- (+) MAC
Burkholderia spp.
- Increased recovery in ____ that reduce growth of P. aeruginosa and other G(-) bacilli
Selective media with antimicrobials
- Most effective
- Selective agar has additional antibiotics to inhibit the growth of normal flora
BCSA (Burkholderia cepacia selective agar)
- Crystal violet, bile salts, polymyxin B, ticarcillin, phenol red
Pseudomonas cepacia
What rank is Burkholderia spp. in terms of causing of pneumonia in patients with CF or chronic granulomatous disease?
Second
Identify the organism.
- Endocarditis (specifically in IV drug abusers)
- Pneumonitis, UTIs, osteomyelitis, dermatitis
- Other wound infections resulting from the use of contaminated water
Burkholderia spp.
Burkholderia spp.
Resistant/Susceptible?
- Aminoglycosides
- Polymyxins
- β-lactam antibiotics
Resistant
Burkholderia spp.
Resistant/Susceptible?
- Chloramphenicol
- Ceftazidime
- Piperacillin
- Minocylcine
- Some fluoroquinolones
- SXT
- Carbapenems (variable)
Susceptible
- 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
- Colonies: yellow
- (+) motile (one or two polar flagella), catalase, urease, glucose, mannitol, MAC
- (-) decarboxylase, oxidase (some are weakly positive)
Burkholderia gladioli
Burkholderia gladioli
Resistant/Susceptible?
- Polymyxin B
- Aztreonam
- Cephalosporins
Resistant
Burkholderia gladioli
Resistant/Susceptible?
- Aminoglycosides
- Carbapenems
- Ciprofloxacin
- SXT
Susceptible
T or F: B. gladioli isolates are more susceptible to antimicrobials than B. cepacia.
T
- Potential bioterrorism agent
- Can be weaponized
- Since it causes a respiratory infection, it spreads easily
- A zoonotic disease
Burkholderia mallei
Identify the organisms.
- Rare in humans: severe local suppurative or acute pulmonary infections
- e.g. Glanders Disease
Burkholderia mallei
- 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
Burkholderia mallei
A respiratory tract zoonosis primarily affecting livestock such as horses, mules, and donkeys
Glanders Disease
Burkholderia mallei
The only drug resistant with Burkholderia mallei?
Polymyxin B
- CLSI recommends ____ with ____ to consider
Broth microdilution with Brucella broth
- 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
- 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
Identify the organism.
- Meliodosis
- Overwhelming septicemia
- Local infections such as orbital cellulitis, dacryocystitis, and draining abscesses, sometimes with with pneumonia
Burkholderia pseudomallei
Burkholderia pseudomallei
Aggressive, granulomatous, pulmonary disease
By ingestion, inhalation, or inoculation of the organisms, with metastatic abscess formation in lungs and other viscera
Meliodosis
- (+) Bipolar staining
- Colonies: wrinkled
- MALDI-TOF for rapid confirmation
- Multiplex polymerase chain reaction (PCR) assays for the identification
Burkholderia pseudomallei
- 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
Burkholderia pseudomallei
Resistant/Susceptible?
- SXT
- Chloramphenicol
- Tetracycline
- Semisynthetic
- Penicillin
- Ceftazidime
Susceptible
- 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
- Resistance is due to continued exposure
- Resistance to ____ is found in the plasmid that can be shared via pili
Penicillin
What are the most commonly encountered species of Moraxella?
- M. catarrhalis
- M. nonliquefaciens
- M. lacunata
- M. osloensis
- M. lincolnii
- M. atlantae
Moraxella spp.
Reclassified as Psychrobacter phenylpyruvicus
M. phenylpyruvica
- 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
- 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
Osloensis and Nonliquefaciens?
Found in the genitourinary tract?
Moraxella osloensis
Osloensis and Nonliquefaciens?
Found in the respiratory tract?
Moraxella nonliquefaciens
- Its 2 species can be differentiated by motility
- Use a Sulfide, Indole, Motility (SIM) medium to observe motility
Oligella spp.
Oligella spp.
The motile species of Oligella
Oligella ureolytica
Oligella spp.
The non-motile species of Oligella
Oligella urethralis
- (+) 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
- (+) 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
- Are weird organisms since these grow well at low temperatures, 5-250C, rarely at 35 deg C
- It thrives in high temperatures
Psychrobacter
- 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
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
Associate the organism with the odor.
- Pseudomonas aeruginosa
- Stenotrophomonas maltophilia
- Burkholderia pseudomallei
A. Ammonia-like
B. Earthy odor
C. Grape-like
- C
- A
- B
- Isolated from urine, blood, CSF, and the genitourinary tract
- (+) urease, phenylalanine deaminase (PDA)
Psychrobacter phenylpyruvicus
