Ch 21 Nonfermenting & miscellaneous gram-negative bacilli

True

Nonfermenting gram (-) bacilli fail to acidify Triple Sugar Iron agar butt & prefer aerobic enviroments

Nonoxidizers/Asacchrolitic

Cannot breakdown carbohydrates

False, must be oxidase positive

True or False: Most nonfermentative gram negative bacilli are oxidase negative, this differentiates them from Enterobacterales

Plesiomonas spp.

What is the only oxidase positive member of Enterobacterales?

Escherichia coli

Give a fermenter that produces acid/yellow with red/alkaline slant on TSIA or KIA (Kligler’s Iron Agar) within 18 hrs of incubation

Diabetes mellitus

Cancer

Steroids

Transplantation

Risk factors for diseases caused by nonfermentative gram (-) bacilli under IMMUNOSUPPRESSION

Pseudomonas aeruginosa

Acinetobacter spp.

Burkholderia spp.

Stenotrophomonas maltophilia

MOST COMMON NONFERMENTING BACTERIA

THAT CLINICALLY CAUSES INFECTION

All true

Nonfermenters are K/K or Red/Red or Alkaline/Alkaline within 18 hours. They are usually oxidase positive, and usually grows on MAC agar. Usually an oxidizer of carbs but some are assacchrolytic.

Pseudomonas luteolus

Pseudomonas oryzihabitans

Burkholderia cepacia

Burkholderia mallei

Nonfermenters that are oxidase negative

Stenotrophomonas maltophilia

Identify the bacteria:

Oxidase: positive

Maltise: positive

Pigment: yellow

Motile (+)

Strongly sacchrolytic

Nonfermenter

Shewanella putrefaciens

Motile, weak or nonsacchrolytic nonfermenters

Indole (-)

Motility (+)

Oxidase (+)

Glucose (-)

ONPG (-)

H2S (+)

Gas (-)

Sphingomonas paucimobilis

Motile, strongly sacchrolytic nonfermenters

Indole (-)

Motility (-)

Oxidase (+)

1 flagella

Pseudomonas aeruginosa

• Green sheen on blood agar

• Grape like odor due to 2-aminoacetophenone

• Specific to P. aeruginosa

  ■ Pyoverdin: Yellow-green

  yellow-brown pigment

  ■ Pyocyanin: Blue pigment

  ○Most are beta-hemolytic

  ○Arginine dihydrolase (ADH) positive

  ○Growth at 42°C

  ○Citrate positive

  ○Cetrimide agar

• Very drug resistant, but aminoglycosides work

PSEUDOMONAS FUORESCENS

PSEUDOMONAS PUTIDA

Fluorescent group

Low virulence

○Isolated from respiratory specimens,

contaminated blood products, urine,

cosmetics, hospital equipment, and fluids

Infections

○UTIs

○Post surgical abscesses

○Empyema

○Septic arthritis

○Wound infections

Grows best at 4C, doesnt grow at 42C

• produces pyoverdin but no pyocyanin

• P. Putida is gel hydrolysis NEGATIVE

• P. fluorescens is gel hydrolysis POSITIVE

• TREATMENTS: Aminoglycosides, polymyxin, piperacillin

PSEUDOMONAS STUTZERI

Wrinkled, leathery, adherent colonies that may produce a light yellow or brown pigment

Soil denitrifier and can grow in anaerobic environment in nitrate containing media

• Arginine dihydrolase negative

• Starch hydrolysis positive

PSEUDOMONAS PSEUDOALCALIGENES

●Contaminant

● Arginine dihydrolase positive and will weakly ferment

fructose

○but does not produce pyoverdine

Oxidase positive

○oxidizes glucose and xylose and

nonproteolytic, hydrolase starch negative

PSEUDOMONAS ALCALIGENES

• ADH negative and strongly ferments fructose

• Contaminant

PSEUDOMONAS LUTEOLA

Rare

P. luteola can be differentiated from P. oryzihabitans By ortho-Nitrophenyl-B-galactoside (ONPG) and Esculin hydrolysis

○ P. Luteola is ONPG positive, and esculin hydrolysis test positive

Both a gram-negative, non-fermentative, oxidase-negative bacilli

Catalase positive, motile, oxidize glucose, grow on

MAC

Acinobacter baumannii

Glucose-oxidizing, nonhemolytic strain

■ May cause opportunistic multidrug resistance in skin and soft tissue infections

■ CRAB (Carbapenem-resistant A. baumannii- susceptible to colistin & tigecycline)

Acinetobacter Iwoffi

Glucose-negative, nonhemolytic strain

Mac purple colonies due to lactose acidification

STENOTROPHOMONAS MALTOPHILIA

Mac BLUISH

• Catalase positive

• Oxidase negative

• DNase positive

• Esculin positive

• Lysine decarboxylase positive

• Gelatin hydrolysis positive

• Usually susceptible to SXT( sulfamethoxazole trimethoprim )

BURKHOLDERIA CEPACIA

• Opportunistic pathogen

• Pneumonia particularly in Cystic fibrosis and chronic granulomatous disease patients

• Endocarditis, UTis, osteomyelitis, dermatitis,wound infections

• Oxidase weak positive-negative

  Motility positive

  ○ Tufts of flagella

• Oxidizes glucose, maltose, lactose, mannitol

• Lysine decarboxylase (LDC) positive

• Ornithine decarboxylase (ODC) positive

• Arginine dihydrolase (ADH) negative

BURKHOLDERIA GLADIOLI

• Resembles B. cepacia

  ○ Can be found in CF and chronic granulomatous disease (CGD) patients

• Yellow colonies after 48-72 hours of incubation

• Motile: polar flagella

• Catalase positive

• Urease positive

• Glucose oxidizer

• Mannitol positive

• Decarboxylase negative

• Oxidase negative

BURKHOLDERIA MALLEI

• Causes glanders

  ○ Can cause severe suppurative or acute

  pulmonary infections

  ○ One case in 50 years (laboratory accident)

• Glanders is zoonosis primarily affecting livestock

• A potential bioterrorism agent

• nonmotile, gram-negative coccobacillus

• Nonpigmented colonies in 2 days

• Glucose oxidizer

• Nitrate (+)

• AFFECTS HORSE SEVERE SUPPURATIVE INFECTION

BURKHOLDERIA PSEUDOMALLEI

• causes Melioidosis

• Transmitted thru Ingestion, inhalation, or inoculation

• Possible agent of bioterrorism

  Commonly found in the soil or mud in South East

  Asia, Mexico, and Australia

• Wrinkled colonies

• Differentiating from Pseudomonas stutzeri is that it

  is non-lactose utilizer

Melioidosis

An aggressive granulomatous pulmonary

disease

○ May cause overwhelming septicemia

MORAXELLA

• Oxidase positive; nonmotile, gram-negative, coccobacilli

• Isolated from respiratory tract, urinary tract, and the eye

○ Rarely cause disease

■ except M. catarrhalis

○ M. nonliquefaciens is part of the normal flora.

• Opportunistic pathogen as they are common residents of the mucous membranes

• Biochemically inert to CHO oxidation and strict aerobes

ROSEOMONAS MUCOSA

Immunocompromised, catheter-related

bloodstream infections

Sabouraud dextrose agar

○

produce pink, mucoid, almost runny colonies

Usually grows on MAC

OLIGELLA

• Small, paired, gram-negative bacilli or coccoid

  organisms

• Most often isolated from the urinary tract

• Potato dextrose agar (PDA) positive

• Oxidase positive

• Nitrate and nitrite positive with gas

• Motile: peritrichous flagella

PSYCHROBACTER IMMOBILIS

Nonmotile

Oxidase positive

Oxidative diplococcus

Optimal temperature for growth is 20°C

CHROMOBACTERIUM VIOLACEUM

• Wound contamination with soil and water

• Purple colonies: Violacein

• Resembles vibrio as they are curved gram-negative bacilli

• Opportunistic pathogen

• Motile: polar flagella

• Catalase positive

• Indole negative can grow in MAC at 42 C

CHRYSEOBACTERIUM INDOLOGENES

Nosocomial and contaminant

WEEKSELLACEAE

• Long, thin bacilli with bulbous ends

• Contaminant of hospital equipment

• Most disease produced by weeksellaceae is caused by Elizabethkingia meningoseptica

• Nonmotile

  Dnase positive

  Oxidase positive

  Gelatin hydrolysis positive

  Indole positive

EMPEDOBACTER

Endophthalmitis from cataract surgery

○ Poor sterilization procedure

SPHINGOBACTERIUM

Septicemia meningitis, peritonitis, and possible Cellulitis

○Isolated from blood and urine

RALSTONIA PICKETTI

• Contaminants of sterile products

  ○ can be isolated from urine, nasopharynx, abscesses, wounds, and blood, usually as colonizers or contaminants

• Slow grower >72 hours of incubation

• Oxidase positive

• Catalase positive

• Reduces nitrate

• glucose and xylose oxidizers

• Motile: single polar flagellum

CUPRIAVIDUS PAUCULA

Opportunistic pathogen that can cause serious infections

○ Septicemia, peritonitis, abscesses, and tenosynovitis

■ Generally in immunocompromised patients

• Motile: peritrichous flagella

  Oxidase positive

  Catalase positive

  saccharolytic, gram-negative bacillus

SHEWANELLA PUTREFACIENS

Infrequent isolates and rarely pathogenic

Abscesses and traumatic ulcers, otitis media, ocular

infections, osteomyelitis, peritonitis, and septicemia

○ Represent colonization

Tan to brown pigments causing greenish discoloration of SBA

Motile

Ornithine decarboxylase

Nitrate positive

H2S positive in TSI

nonhalophilic and saccharolytic

Positive oxidase test differentiates Shewanella from other Enterobacteriaceae

SPHINGOMONAS PAUCIMOBILIS

Found in water sources including swimming pools,

hospital equipment, and laboratory supplies

○

Peritonitis associated with CAPD,

septicemia, meningitis, leg ulcer, empyema,

and splenic and brain abscesses

○Additionally isolated in sputum, urine, and vaginal specimens

MAC: yellow pigment does not grow

Requires more than 48 hours to culture on SBA

Oxidase weak positive

Motile: 18-22oC but not at 37oC

Indole negative

Oxidizers

SPHINGOMONAS PARAPAUCIMOBILIS

● Resembles Sphingomonas paucimobilis

○ Except they are H2S POSITIVE by lead acetate method

● Simon citrate positive

●DNase negative