Bacte - Non-Fermentative Gram-Negative Bacilli (PART 2)

MORAXELLA

• Gram-negative coccobacillary or bacillary organisms
• Nonmotile
• Strongly oxidase (+)
• Strictly aerobic
• Asaccharolytic
• Susceptible to Penicillin
• Opportunists that reside on the mucous membranes of humans and animals
• can be isolated from the respiratory tract, urinary tract, and eyes

MORAXELLA CATARRHALIS

Most frequent isolate from clinical specimens especially from respiratory and ear specimens.

MORAXELLA CATARRHALIS

• Opportunistic pathogen
• 3rd most common cause of acute otitis media & sinusitis in children
• Commensal of the upper respiratory tract of humans

MORAXELLA CATARRHALIS

It can also cause lower respiratory tract infection especially in adults with chronic obstructive pulmonary disease.
Resembles Neisseria due to Gram-negative coccal morphology

MORAXELLA CATARRHALIS

smooth, opaque, gray-to-white colonies “hockey puck” colonies because the colony remains intact when pushed across the plate with a loop.

MORAXELLA NONLIQUEFACIENS

Second most frequently isolated Normal flora of the respiratory tract of humans
Does not grow on MacConkey Agar
Rarely causes disease in humans.

MORAXELLA OSLOENSIS

Normal flora in the genitourinary tract
Similar morphologically and biochemically to M. nonliquefaciens

MORAXELLA LACUNATA

Common conjunctival isolate
Eye infections
Able to liquefy serum
Depressions are formed on the surface of Loeffler’s serum agar slant.

OLIGELLA

Small, paired, Gram negative bacilli or coccoid
Usually isolated from the urinary tract

Oligella urethralis and Oligella ureolytica

are two asaccharolytic coccobacilli species

Oligella urethralis

asaccharolytic nonmotile coccobacilli

Oligella ureolytica

asaccharolytic motile coccobacilli with peritrichous flagella

OLIGELLA

Do not grow on MAC
Nonoxidative (-)
Phenylalanine deaminase (PDA) (+) Differentiate organisms from Alcaligenes species.
Oxidase (+)
Nitrate and nitrite (+) with gas formation

Urease hydrolysis

key test for differentiating Oligella urethralis and Oligella ureolytica (hydrolyze within minutes)

ALCALIGENES

Gram-negative strict aerobic rods or coccobacilli
Found in water (e.g., swimming pools, tap water, dialysis fluids)
Resistant to disinfectants, such as chlorhexidine and quaternary ammonium compounds
Obligate aerobe
Motile with 1-12 peritrichous flagella

ALCALIGENES FAECALIS

Fruity odor
Reduce nitrate to gas (+)
Linked to pancreatic abscesses

ACHROMOBACTER

Gram-negative non-sporulating motile rods
1-20 peritrichous flagella
Obligate aerobe
Non-fermentative
Grows on MacConkey Agar

Achromobacter denitrificans

Has been recovered from urine, prostate secretions, the buccal cavity, floral fluid, and eye secretions.
Can also reduce nitrate to nitrite (+) then nitrate to gas (+)

ACHROMOBACTER XYLOSOXIDANS

Most commonly isolated from the genus achromobacter

CHROMOBACTERIUM VIOLACEUM

Reservoirs are soil and water
Commonly found in tropical and subtropical climates, in particular Southeast Asia and India
Opportunistic pathogen
Immunocompromised patients with neutrophil deficits, including Chronic Granulomatous Disease.
Skin lesion is the typical portal of entry
Motile with polar flagella

CHROMOBACTERIUM VIOLACEUM

Grows on MAC
Colonies are mostly
Beta-hemolytic and have an almond-like odor.
Most strains produce a violet pigment called Violacein.

Violacein

: ethanol-soluble, water insoluble pigment

ELIZABETHKINGIA MENINGOSEPTICA

Causes meningitis or septicemia in newborns
Causes pneumonia, endocarditis, bacteremia, and meningitis in adults

ELIZABETHKINGIA MENINGOSEPTICA

Produce acid from glucose, maltose, and mannitol
Growth on MacConkey Agar is variable.
Hydrolyze esculin (+)
Indole (+)

RALSTONIA

Contaminate hospital fluids

RALSTONIA PICKETTII

motile by means of a single polar flagellum
Slow growers, requiring more than 72 hours on primary cultures before colonies are visible
Grows on MAC
Oxidizes glucose and xylose
Oxidase (+)
Catalase (+)

SPHINGOMONAS PAUCIMOBILIS

Optimal growth is at 30 ℃ in 5% CO2 or ambient air.
Isolated from water sources.
Known for their waterborne nature.
Causes peritonitis
Obligately aerobic
Oxidizers

SPHINGOMONAS PARAPAUCIMOBILIS

Isolated from sputum, urine, and vaginal specimens
Motile
Grows in deep yellow pigment.
Does not grow on MAC.

H2S positive by the lead acetate method (+), simmon citrate, extracellular DNAse

S. parapaucimobilis can be distinguished from Sphingomonas paucimobilis through these biochemical test.

HAEMOPHILUS

Facultative anaerobes
Obligate parasites on the mucous membranes of humans and animals
Gram negative, pleomorphic coccobacilli or rods
Nonmotile
Obligate parasites on the mucous membranes of humans and animals
Require growth factors found in blood

AGGREGATIBACTER ACTINOMYCETEMCOMITANS

major contributor to periodontitis
normal oral flora in humans
Human tissue infections have been attributed to bites by cattle, pigs and horses or through contact with these animals
gram-negative, non–spore-forming coccobacillus or short rod
Formerly classified in the genus actinobacillus.

PERIODONTITIS

Also called gum disease and is a serious infection that damages the soft tissue around teeth. Cause destruction to the alveolar bone that supports the teeth

AGGREGATIBACTER ACTINOMYCETEMCOMITANS

has a major virulence factor which is collagenase and a leukotoxin that is toxic to PMNs and monocytes.

AGGREGATIBACTER ACTINOMYCETEMCOMITANS

“star-shaped” colonies, often seen at
48 hours
grows both aerobically and anaerobically
addition of 5% to 10% CO2 enhances growth
(+) Oxidase, glucose fermentation

AGGREGATIBACTER APHROPHILUS

From the greek word “aphros” and “philia” meaning foam (?) loving or organisms desiring high concentrations of carbon dioxide
One of the most prevalent species in the HACEK group involved in endocarditis
Found in dental plaque and gingival scrapings
Fever, heart murmur, congestive heart failure, and embolism

AGGREGATIBACTER APHROPHILUS

convex, granular, and yellow colonies with an opaque zone near the center on chocolate agar

CARDIOBACTERIUM HOMINIS

Pleomorphic, nonmotile, non-spore-forming, fastidious,
Gram-negative bacilli
Normal flora of the nose, mouth, throat, may also be found in genitourinary and gastrointestinal tracts
Bacterial endocarditis, periodontitis, peritonitis

CARDIOBACTERIUM HOMINIS

Infects the aortic valve more frequently compared with the other HACEK

CARDIOBACTERIUM HOMINIS

Shows/form clusters or rosettes when gram stains are prepared from 5% BA.
Gram stains show false gram-positive reactions
facultative anaerobe (5% CO2)
enhanced in microaerophilic conditions

EIKENELLA CORRODENS

Formerly classified as Bacteroides corrodens “Corroding” bacilli- pits or makes a depression or corrodes the surface of the agar
Normal flora of the bowel and oral cavity Infections occur from trauma especially after human bites or fights (e.g. clenched fist wounds or broken skin by human teeth)

EIKENELLA CORRODENS

Predilection for attachment to heart valves
Least common isolate of the HACEK group in adult infectious endocarditis

EIKENELLA CORRODENS

Produce yellow pigment
Chlorine bleach–like odor from the agar surface
Do not grow on MAC agar or eosin-methylene blue (EMB) agar

KINGELLA KINGAE

Coccobacillary to short bacilli with squared ends that occur in pairs or short chains
Normal oropharynx flora
Resist decolorization in Gram stain
Nonmotile

KINGELLA KINGAE

Causes indolent, slowly progressive endocarditis Important pathogens in pedriatic population and has a predilection for bones and joints
Most common cause of osteoarthritis infection in children younger than 4 years of age

KINGELLA KINGAE

large white-to-beige β-hemolytic colonies, spreading, corroding colony on SBA