Infectious Disease and Microbiology – Pseudomonas luteola

Overview

Pseudomonas luteola is a Gram-negative bacillus that is an uncommon cause of human infection. It was formerly known as Chryseomonas luteola and is encountered primarily as an opportunistic pathogen.

Human infections are rare but have been reported worldwide. Important clinical manifestations include bacteremia/septicemia, central venous catheter-associated infection, wound infection, peritoneal dialysis-associated peritonitis, prosthetic valve endocarditis, and meningitis.

Classification

Genus: Pseudomonas

Species: Pseudomonas luteola

Former name: Chryseomonas luteola

Organism type: Gram-negative bacillus

Microbiologic Characteristics

P. luteola is a:

• Gram-negative bacillus

• Environmental organism

• Opportunistic pathogen

• Rare cause of invasive human infection

An important historical laboratory characteristic is the production of:

Yellow-pigmented colonies

The species name luteola reflects this yellow pigmentation.

High-Yield Microbiology Pattern

Gram-negative bacillus

• ●

Yellow-pigmented colonies

• ●

Rare opportunistic infection

• ●

Foreign body or catheter

→ Consider Pseudomonas luteola

Epidemiology

P. luteola has a:

Worldwide distribution

However, human infection is:

Rare

The organism is primarily environmental and may be encountered in:

• Soil

• Water

• Moist environmental sources

Human disease generally occurs opportunistically rather than as a common community infection.

Risk Factors

Reported infections frequently occur in patients with:

• Central venous catheters

• Prosthetic cardiac material

• Peritoneal dialysis catheters

• Recent surgery or trauma

• Open wounds

• Other invasive medical devices

• Significant underlying disease

Thus, the presence of:

Foreign material

is an important clinical clue.

Septicemia and Bacteremia

One of the important manifestations is:

Septicemia/bacteremia

Some cases may be:

Polymicrobial

The source particularly emphasizes an association with:

Central venous catheters

Central Venous Catheter Infection

A central venous catheter can provide a surface for:

Bacterial adherence

and potentially persistent bloodstream infection.

A typical sequence is:

Environmental organism

↓

Contamination or colonization of device

↓

Catheter-associated infection

↓

Bacteremia/septicemia

High-Yield Clinical Pattern

Central venous catheter

• ●

Unusual Gram-negative bacillus

• ●

Bacteremia

→ Consider an opportunistic environmental organism such as P. luteola

Polymicrobial Infection

The source notes that septicemia may sometimes be:

Polymicrobial

Therefore, isolation of P. luteola does not necessarily mean that it is the only organism contributing to the infection.

Management should address:

All clinically significant pathogens

identified from appropriate cultures.

Wound Infection

P. luteola can cause:

Wound infections

This is consistent with its environmental reservoir and opportunistic behavior.

Potential settings include:

• Traumatic wounds

• Surgical wounds

• Contaminated tissue

• Patients with impaired host defenses

Peritoneal Dialysis-Associated Peritonitis

An important manifestation is:

Peritonitis

in patients receiving:

Peritoneal dialysis

The dialysis catheter provides a potential route by which environmental organisms can enter the peritoneal cavity.

High-Yield Dialysis Pattern

Peritoneal dialysis

• ●

Peritonitis

• ●

Rare environmental Gram-negative bacillus

→ Consider Pseudomonas luteola

Prosthetic Valve Endocarditis

P. luteola has also been reported as a cause of:

Prosthetic valve endocarditis

The presence of:

Prosthetic cardiac material

provides a surface that may facilitate persistent infection.

High-Yield Endocarditis Pattern

Prosthetic heart valve

• ●

Endocarditis

• ●

Unusual environmental Gram-negative bacillus

→ Consider P. luteola

Meningitis

Rare cases of:

Meningitis

have also been reported.

This represents an uncommon but potentially serious invasive manifestation.

Diagnosis

The primary diagnostic method is:

Culture

Depending on the clinical syndrome, appropriate specimens may include:

• Blood

• Catheter-associated blood cultures

• Wound specimens

• Peritoneal dialysis fluid

• Cerebrospinal fluid

• Other normally sterile specimens

Organism Identification

Because P. luteola is uncommon, accurate laboratory identification is important.

The historical name:

Chryseomonas luteola

may appear in older literature.

Recognition of the organism as a potential pathogen is especially important when it is repeatedly recovered from:

Normally sterile sites

or in association with:

Intravascular/prosthetic devices

Contamination vs. True Infection

Because P. luteola is an environmental organism, an unusual culture result should be interpreted within the clinical context.

True infection is more likely when there is:

• Compatible clinical disease

• Repeated positive cultures

• Isolation from a normally sterile site

• Central venous catheter involvement

• Prosthetic material

• Peritoneal dialysis-associated infection

• Appropriate inflammatory findings

Treatment

The source lists:

Ceftazidime

as the principal treatment.

However, because P. luteola infections are uncommon and susceptibility patterns can vary, treatment should ideally be guided by:

Culture and antimicrobial susceptibility testing

Additional Treatment Options

The source lists:

• Ureidopenicillins

• Aminoglycosides

• Imipenem

• Meropenem

• Ciprofloxacin

The appropriate antimicrobial depends on:

• Susceptibility results

• Site of infection

• Severity

• Renal function

• Presence of prosthetic or catheter material

Source Control

Because many reported infections involve:

Foreign material

management may require more than antimicrobial therapy.

Possible interventions include:

• Removal or replacement of an infected central venous catheter

• Management of an infected peritoneal dialysis catheter

• Debridement of an infected wound

• Evaluation of infected prosthetic cardiac material

High-Yield Treatment Principle

Device-associated P. luteola infection

→ Culture and susceptibility-guided antibiotics

• ●

→ Appropriate source control

Pseudomonas luteola vs. Pseudomonas aeruginosa

Although both carry the Pseudomonas name, they should not automatically be considered clinically identical.

Pseudomonas aeruginosa

→ Major human opportunistic pathogen

→ Common healthcare-associated infections

→ Characteristic blue-green pigments

→ Numerous well-established virulence factors

→ Frequently multidrug resistant

Pseudomonas luteola

→ Rare human pathogen

→ Environmental organism

→ Historically called Chryseomonas luteola

→ Characteristically associated with yellow pigmentation

→ Reported particularly with catheters and prosthetic material

Device-Associated Disease

A useful way to remember P. luteola is:

RARE ENVIRONMENTAL GRAM-NEGATIVE BACILLUS

• ●

FOREIGN BODY

The important foreign-body settings include:

Central venous catheter

Peritoneal dialysis catheter

and

Prosthetic heart valve

High-Yield Clinical Pattern

Rare environmental Gram-negative bacillus

• ●

Yellow-pigmented colonies

• ●

Central venous catheter-associated bacteremia

→ Think Pseudomonas luteola

Exam Essentials

Genus: Pseudomonas

Species: P. luteola

Former name: Chryseomonas luteola

Type: Gram-negative bacillus

Distribution: Worldwide

Frequency: Rare human infection

Reservoir: Primarily environmental

Pigment: Characteristically yellow

Clinical behavior: Opportunistic pathogen

Major infection: Bacteremia/septicemia

Important association: Central venous catheters

Other infections: Wound infection, peritoneal dialysis-associated peritonitis, prosthetic valve endocarditis, and meningitis

Polymicrobial disease: May occur

Diagnosis: Culture

Source treatment: Ceftazidime

Additional source agents: Ureidopenicillins, aminoglycosides, imipenem, meropenem, and ciprofloxacin

Treatment principle: Susceptibility-guided antimicrobial therapy

Device-associated infection: Consider appropriate source control

Key clinical pearl: Pseudomonas luteola, formerly Chryseomonas luteola, is a rare environmental Gram-negative bacillus notable for yellow pigmentation and opportunistic infections involving foreign material. The most useful clinical clue is an unusual Gram-negative bacteremia associated with a central venous catheter, although peritoneal dialysis peritonitis and prosthetic valve endocarditis are also characteristic reported presentations.