Pseudomonas is a gram negative bacterium that grows on yellow-green agar colonies. It is occasionally found in anogenital and axilla areas of normal skin and rarely in the stools. The organisms commonly contaminate lesions populated with harmful organisms and causes infection to tissues exposed to external environment.
Pseudomonas infections develop in different anatomic locations including subcutaneous tissue, skin, ears, eyes, bone, urinary tract and heart valves. The site infected depends on the mode of entry.
Pseudomonas is also the common cause of UTI in patients who have obstructive uropathy and urologic manipulation. Also, patients who have respiratory infection connected to endotracheal tubes, tracheostomy and IPPB treatment where in Pseudomonas have joined other rods that are gram-negative colonizing in the oropharynx.
Pseudomonas is an opportunistic pathogen causing nosocomial infections. Aside from being a life-threatening disease, it is often resistant to most antibiotics over time and developed new resistance after exposing to antimicrobial agents. Some species of pseudomonas that were identified as causative agents are now examined to be use as a biological warfare agent.
· Pseudomonas aeruginosa (hormology group 1)
· Pseudomonas cepecia (group 2)
· Pseudomonas pseudomallei (group 2)
· Pseudomonas mallei (group 2)
Pseudomonas infection is the most serious complication that can happen in debilitated patients with inability to fight organisms due to other diseases and therapy.
It often occurs in the hospital in moist areas such as antiseptic solutions, sinks, and urine receptacles. The cross infection is transmitted from patient to patient through the hands of medical personnel usually in burn, urinary tract infection and neonatal intensive care units.
Symptoms include chills fever and purulent matter production on infected wounds.
Pseudomonas infection is diagnosed through culturing the site of infection.
If the infection is external and localized, irrigations of 1% acetic acid or topic agents like colistin or polymyxin B are effective treatments. In cases with abscess, it should be drained and necrotic tissue should be debrided.
Parenteral therapy is also done by divided doses of 5mg/kg/day of aminoglycoside antibiotic such as gentamicin and tobramycin inhibiting further Pseudomanas infection.
Other antibiotics include several penicillins such as ticarcillin, carbenicillin, mezlocillin, piperacillin, and azlocillin are also effective against Pseudomonas.
The choice of antibiotic to be used should be based on the pseudomonas sensitivity through culture.
Mortality and Morbidity
Pseudomonas infection in sepsis, bacteremic pneumonia, burn wound infections, meningitis and others are associated with high mortality rate.
Bacterial keratitis causes monocular blindness where in pseudomonas is also the cause.
Melioidosis bloodstream infection and untreated glanders causes death to infected people within 7 to 10 days. Pseudomonas aeruginosa has an estimated mortality rate of 50% higher than other gram-negative infections. Bacteremic type of pseudomonal pneumonia is associated with mortality which occurs in 3 to 4 days after the first symptoms of pulmonary infection or extrapulmonary infection. Pseudomas aeruginosa in ventilator-associated pneumonia has higher mortality rate of 68% than VAP caused by other organisms.