Question

What morphological and physiological features distinguish Burkholderia cepacia from Pseudomonas aeruginosa? In what common environments might these organisms be encountered? (Sections 15.2, 15.4)

Short answer

Burkholderia cepacia and Pseudomonas aeruginosa differ in pigments and metabolic capabilities. They are found in soil, water, and as human pathogens, particularly in immunocompromised individuals.

Step-by-step solution

- Introduction

First, identify what is being compared: Burkholderia cepacia and Pseudomonas aeruginosa. Both are Gram-negative bacteria commonly found in various environments.

- Morphological Features

Outline the key morphological differences: 1. **Burkholderia cepacia**: Rod-shaped, often appear in pairs, motile with polar flagella.2. **Pseudomonas aeruginosa**: Rod-shaped, usually single or in pairs, also motile with a single polar flagellum.

- Physiological Features

Compare their physiological characteristics:1. **Burkholderia cepacia**: Oxidase positive, capable of producing yellow pigment, can degrade a wide range of organic molecules.2. **Pseudomonas aeruginosa**: Oxidase positive, produces blue-green pigment (pyocyanin), notable for its fruity odor.

- Common Environments

Identify common environments where they might be found:1. **Burkholderia cepacia**: Soil, water, and plant root environments. Also associated with opportunistic infections in humans, particularly in cystic fibrosis patients.2. **Pseudomonas aeruginosa**: Soil, water, and on various surfaces including hospital environments. Known for causing infections in immunocompromised patients.

- Conclusion

Summarize the distinguishing features and environments: Burkholderia cepacia and Pseudomonas aeruginosa can be distinguished by their pigments, metabolic capabilities, and preferred environments. Both are environmental organisms with significant roles in human infections.

Key concepts

Morphological Features

Burkholderia cepacia and Pseudomonas aeruginosa are interesting bacteria often found in various environments. Both are rod-shaped, but there are key differences in their morphology. Burkholderia cepacia typically appears in pairs and is motile with polar flagella. On the other hand, Pseudomonas aeruginosa usually exists singly or in pairs, and it also has a single polar flagellum for motility. These differences in their physical shapes and movement structures are vital for their identification and characterization.

Physiological Characteristics

When we talk about the physiological characteristics of Burkholderia cepacia and Pseudomonas aeruginosa, we focus on their biochemical abilities and behaviors. Burkholderia cepacia is oxidase positive, meaning it can produce the enzyme oxidase. It can also produce a yellow pigment and degrade a wide range of organic molecules, which makes it incredibly adaptable. In contrast, Pseudomonas aeruginosa is also oxidase positive but produces a distinctive blue-green pigment called pyocyanin. This bacterium is notable for its fruity odor, which can be a key clue when identifying it in a lab setting.

Common Environments

Both Burkholderia cepacia and Pseudomonas aeruginosa are environmental bacteria and can be found in a variety of settings. Burkholderia cepacia is commonly found in soil, water, and on plant roots. It's also associated with opportunistic infections in humans, particularly in patients with cystic fibrosis, where it can cause severe complications. Pseudomonas aeruginosa can also be found in soil and water but is additionally prevalent on various surfaces, including those in hospital environments. This makes it a frequent culprit in hospital-acquired infections, particularly in immunocompromised patients.

Microbial Infections

Microbial infections caused by Burkholderia cepacia and Pseudomonas aeruginosa can be severe. Burkholderia cepacia is notorious for causing respiratory infections in patients with cystic fibrosis, leading to decreased lung function and increased morbidity. Pseudomonas aeruginosa, on the other hand, affects a broader range of individuals, especially those who are immunocompromised. It can lead to infections in the blood, lungs (pneumonia), and other parts of the body following surgery. Both bacteria are inherently resistant to many antibiotics, making infections difficult to treat.

Environmental Bacteria

As environmental bacteria, Burkholderia cepacia and Pseudomonas aeruginosa play significant roles in their habitats. Burkholderia cepacia, with its ability to degrade various organic substances, is crucial in recycling nutrients and maintaining soil health. Its presence in plant root environments also implies a mutualistic relationship promoting plant growth. Pseudomonas aeruginosa, while capable of existing in similar environments, is particularly notable for its adaptability to adverse conditions, including those in hospital settings. This adaptability highlights the importance of environmental bacteria in ecological balance and their potential impacts on human health.