Question

Burkholderia and Pseudomonas aeruginosa are common sources of hospital infections. Several characteristics make them difficult to eradicate. Which one of the following in NOT one of the reasons?

Answer 1

Ans.

Burkholderia cepacia [burk-hōld–er–ee-uh si–pay–shee–uh] (also called B. cepacia) is the name for a group or “complex” of bacteria that can be found in soil and water. B. cepacia bacteria are often resistant to common antibiotics.

Pseudomonas aeruginosa is a frequent causative pathogen in healthcare associated infections [1]. P. aeruginosa is the most common Gram-negative pathogen causing nosocomial pneumonia in the United States, and it is frequently implicated in hospital-acquired urinary tract and bloodstream infections

Pseudomonas aeruginosa commonly inhabits soil, water, and vegetation. It is found in the skin of some healthy persons and has been isolated from the throat (5 percent) and stool (3 percent) of nonhospitalized patients.

The pseudomonads are a heterogeneous group of gram-negative bacteria that have in common an inability to ferment lactose. Formerly classified in the genus Pseudomonas, the members of this group have been assigned to three medically important genera—Pseudomonas, Burkholderia, and Stenotrophomonas—whose biologic behaviors encompass both similarities and marked differences and whose genetic repertoires differ in many respects. The pathogenicity of most pseudomonads is based on opportunism; the exceptions are Burkholderia pseudomallei and Burkholderia mallei, which are primary pathogens.

Pseudomonas aeruginosa, the major pathogen of the group, is a significant cause of infections in hospitalized patients and in patients with cystic fibrosis (CF; Chap. 285). Cytotoxic chemotherapy, mechanical ventilation, and broad-spectrum antibiotic therapy set up conditions that predispose to colonization and infection of increasing numbers of hospitalized patients by this pathogen. The other members of the genus Pseudomonas—Pseudomonas putida, Pseudomonas fluorescens, and Pseudomonas stutzeri—infect humans infrequently.

The genus Burkholderia comprises >40 species, of which Burkholderia cepacia is most frequently encountered in Western countries. Like P. aeruginosa, B. cepacia is both a nosocomial pathogen and a cause of infection in CF. The other medically important members of this genus are B. pseudomallei and B. mallei, the etiologic agents of melioidosis and glanders, respectively.

The genus Stenotrophomonas contains one species of medical significance, Stenotrophomonas maltophilia (previously classified in the genera Pseudomonas and Xanthomonas). This organism is strictly an opportunist that “overgrows” in the setting of potent broad-spectrum antibiotic use.

Diseases with multiple hosts are difficult to target for eradication because it often means that the disease will have to be eradicated in all of them. Pathogens, which cause diseases such as poliomielitis, measles, mumps, rubella, diphtheria and whooping cough, all have a single host — humans.

In the CF airway, P. aeruginosa exist as biofilms. It has been suggested that antibiotic resistance results from poor antibiotic penetration into the biofilm, phenotypic differences between biofilm and planktonic (free) bacteria, or both factors.

Of the many different types of Pseudomonas, the one that most often causes infections in humans is called Pseudomonas aeruginosa, which can cause infections in the blood, lungs (pneumonia), or other parts of the body after surgery.

Symptoms

Ears: Pain, itching, and liquid discharge.

Skin: Rashes, which may consist of pus-filled pimples.

Eyes: Pain and redness.

In the lungs: Pneumonia, coughing, and congestion.

Soft tissue: Discharge of green pus and a sweet, fruity smell.

In the blood: Joint pain and stiffness, fever, chills, and fatigue.