Epidemiology - Pseudomonas aeruginosa

Epidemiology

P. aeruginosa are the opportunistic pathogens, causing infec-tion, distributed worldwide.

◗ Geographical distribution

P. aeruginosa infection is ubiquitous in most environmentalplaces in the hospital. The bacteria are specially found in the hospital environment, such as toilet, bath tubs, wash basins, respiratory and dialysis equipments, kitchens, and even in anti-septic or disinfectant solutions.

◗ Habitat

P. aeruginosa is a common human saprophyte present widely inthe environment. In hospitalized patients, P. aeruginosa tran-siently colonizes the respiratory and gastrointestinal tract of the patients. The colonization is common in patients, partic-ularly those hospitalized for a very long period, treated with broad-spectrum antibiotics over a long duration, and those exposed to respiratory therapy by instrumentation.

◗ Reservoir, source, and transmission of infection

Hospital environment is the most common source and res-ervoir of infection. Pseudomonal infections are transmitted through aerosols and by contact with infectious materials. P. aeruginosa is responsible for nearly 5–15% of hospital or noso-comial infections.

◗ Pyocin typing

Typing of P. aeruginosa based on the production of pyocin is the most commonly used method for typing P. aeruginosa strains. These are used in epidemiology studies. Pyocins are bacterio-cins produced by P. aeruginosa. Three types of pyocins are pro-duced. They are R, F, and S pyocins. The capability to produce these pyocins is observed in more than 90% of strains of P.aeruginosa. Those strains that produce pyocins are resistant totheir own pyocins, but are sensitive to those produced by other strains.