The history of blue pus

Infectious diseases have become the third leading cause of death in the United States, and for over 100 years of American surgery, Pseudomonas aeruginosa has been recognized as an important cause of pneumonia and blood, wound, and urinary tract infections. The overall frequency of Pseudomonas aeruginosa infections has not decreased this past decade. Centers for Disease Control (CDC) data derived from the 1990–1992 National Nosocomial Infections Surveillance (NNIS) system report that Pseudomonas aeruginosa caused 9% of infections of all sites and 8% of surgical site infections. Centers for Disease Control data from 1980–82 report that Pseudomonas aeruginosa caused 8.5% of nosocomial infections of all sites and 8.1% of surgical wound infections. Centers for Disease Control 1990–1992 nosocomial data also show that Pseudomonas aeruginosa caused 11% of urinary tract infections, 16% of pneumonias, and 3% of bloodstream infections. Pseudomonas aeruginosa (9%) is one of the top five causes of nosocomial infections in all sites behind Escherichia coli (12%), Staphylococcus aureus (12%), coagulase-negative staphylococci (11%), and Enterococcus spp. (10%), and causes a higher mortality than most pathogens. NNIS data from 1986–1990 indicate that Pseudomonas aeruginosa is the most common pathogen in intensive care units (ICU) and is the leading cause of nosocomial pneumonia in ICU and hospital-wide patients. Similarly, Pseudomonas aeruginosa was one of the most frequently reported microorganisms in a 1992 European study of the prevalence of ICU-acquired infections. Pseudomonas aeruginosa is an opportunistic extracellular pathogen whose hospital prevalence has paralleled the emergence of transcutaneous medical devices, immunosuppressive therapies, mechanical ventilators, the increased incidence and survival of immunosuppressed patients, and most importantly, the development of antibiotic resistance promoted by factors such as inappropriate antibiotic use. Another factor facilitating the emergence of Pseudomonas aeruginosa as a predominant pathogen causing invasive burn wound infections is the initial use of broad-spectrum antibiotics effective against Staphylococcus during a patient’s course of treatment. Pseudomonas aeruginosa uses multiple virulent factors to infect high-risk, immune suppressed patients with burns, cystic fibrosis, cancer, trauma, organ transplants, and serious underlying disease. Intrinsic multidrug resistance to a variety of antimicrobial agents plays a major virulent role and results from mechanisms including mutation of the DNA gyrase gene, synthesis of altered penicillin-binding proteins, b-lactamases, low outer membrane permeability to antibiotics, and from plasma membrane antibiotic efflux pumps. Additional virulent factors include endotoxin, pyocyanin, proteolytic enzymes (eg, elastase, collagenases), a functioning flagellum, toxins, alginate (mucoid coat), surface adhesins such as pili, and various outer membrane proteins collectively referred to as nonpilin adhesins.