Carbapenem-Resistant Pseudomonas Aeruginosa at US Emerging Infections Program Sites, 2015

Maroya Spalding Walters; Julian E. Grass; Sandra N. Bulens; Emily B. Hancock; Erin C. Phipps; Daniel Muleta; Jackie Mounsey; Marion A. Kainer; Cathleen Concannon; Ghinwa Dumyati; Chris Bower; Jesse Jacob; P. Maureen Cassidy; Zintars Beldavs; Karissa Culbreath; Walter E. Phillips, Jr.; Dwight J. Hardy; Roberto L. Vargas; Margret Oethinger; Uzma Ansari; Richard Stanton; Valerie Albrecht; Alison Laufer Halpin; Maria Karlsson; J. Kamile Rasheed; Alexander Kallen


Emerging Infectious Diseases. 2019;25(7):1281-1288. 

In This Article

Abstract and Introduction


Pseudomonas aeruginosa is intrinsically resistant to many antimicrobial drugs, making carbapenems crucial in clinical management. During July–October 2015 in the United States, we piloted laboratory-based surveillance for carbapenem-resistant P. aeruginosa(CRPA) at sentinel facilities in Georgia, New Mexico, Oregon, and Tennessee, and population-based surveillance in Monroe County, NY. An incident case was the first P. aeruginosa isolate resistant to antipseudomonal carbapenems from a patient in a 30-day period from any source except the nares, rectum or perirectal area, or feces. We found 294 incident cases among 274 patients. Cases were most commonly identified from respiratory sites (120/294; 40.8%) and urine (111/294; 37.8%); most (223/280; 79.6%) occurred in patients with healthcare facility inpatient stays in the prior year. Genes encoding carbapenemases were identified in 3 (2.3%) of 129 isolates tested. The burden of CRPA was high at facilities under surveillance, but carbapenemase-producing CRPA were rare.


Pseudomonas aeruginosa is an opportunistic pathogen that causes an estimated 51,000 healthcare-associated infections (HAI) in the United States annually and was the third most common gram-negative cause of selected HAI reported to the National Healthcare Safety Network (NHSN) during 2011–2014.[1,2] Infections caused by P. aeruginosa are associated with substantial morbidity and mortality rates; a recent study of bloodstream infections showed that patients with a Pseudomonas bloodstream infection had a higher mortality rate than patients with infections caused by members of Enterobacteriaceae or other non–lactose fermenting gram-negative bacilli.[3] Infections with P. aeruginosa are often challenging to treat because of its intrinsic nonsusceptibility to many commonly used antimicrobial drugs; ≈13% of isolates causing HAI are multidrug resistant (MDR).[2] For these reasons, carbapenems have become important antimicrobial drugs for clinical management of serious P. aeruginosa infections.

Carbapenem resistance among Pseudomonas spp. is a concern; in 2014, 19.1% of P. aeruginosa associated with selected HAI and reported to the NHSN were not susceptible to carbapenems.[4] Although this proportion has remained stable since 2009,[1,5] some reports have suggested recent increases in the prevalence of carbapenem-resistant P. aeruginosa (CRPA) among certain subpopulations, including children.[6]

Carbapenem resistance in P. aeruginosa is due primarily to chromosomal mutations that alter porins, modify efflux pump activity, and derepress intrinsic β-lactamases. However, carbapenemase genes, commonly carried on mobile genetic elements, have the potential for rapid dissemination. A study of isolates from 14 countries in Europe showed that the prevalence of metallo-β-lactamase (MBL)–producing P. aeruginosa increased from 12.3% in 2010 to 30.6% in 2011.[7]

In the United States, carbapenemase-producing CRPA (CP-CRPA) was first reported in 2001 in an isolate producing the Verona Integron Mediated (VIM) MBL from a cancer patient in Texas.[8] CP-CRPA expressing the Klebsiella pneumoniae carbapenemase (KPC),[9] the active-on-imipenem (IMP) MBL,[10,11] and New Delhi MBL (NDM) have also been identified,[10,12,13] and healthcare-associated outbreaks of VIM-producing CRPA have occurred.[14] Recent data from a convenience sample of CRPA tested through the Antibiotic Resistance Laboratory Network found that 1.9% of isolates produced a carbapenemase.[15]

To date, the epidemiology of CRPA in the United States has not been systematically evaluated. Through the Centers for Disease Control and Prevention (CDC) Emerging Infections Program, we piloted surveillance for CRPA in 5 US metropolitan areas with the objective of developing a laboratory-based surveillance system to describe the epidemiology of CRPA.