“Superbug” Klebsiella Pneumoniae, a carbapenem-resistant Enterobacteriaceae (CRE) claimed the life of a Reno Nevada woman in 2016. This was in the heals of two highly publicized deaths at UCLA Medical Center in 2015. That strain was resistant to all available (26) antimicrobial drugs. Although the patient was hospitalized in Nevada, the pathogen was reportedly contracted in India.
CRE bacteria is more widespread in the U.S. than previously thought and should be more closely monitored. The CDC states that CRE causes approximately 9,300 infections a year and estimated to cause over 600 deaths in the United States annually. The CDC believes those numbers are increasing but don’t have good national data. The CDC does report that CRE infections have been reported in 42 states and roughly 4% of U.S. hospitals had at least one patient with a CRE infection in the first half of 2012. The number increased to 18% of long-term acute care facilities.
CRE is deadly with a mortality rated from 40% to 50%. The bacteria often reside in the intestine but problems generally occur when they developin other areas, such as the urinary tract, lungs, skin, and on medical equipment. In the cases at UCLA, they were tracked back to a duodenoscope.
With regard to the case in Nevada: from the MMWR:
The specific CRE, Klebsiella pneumoniae, was isolated from a wound specimen collected on August 19, 2016. After CRE was identified, the patient was placed in a single room under contact precautions. The patient had a history of recent hospitalization outside the United States. Therefore, based on CDC guidance (1), the isolate was sent to CDC for testing to determine the mechanism of antimicrobial resistance, which confirmed the presence of New Delhi metallo-beta-lactamase (NDM).
The patient was a female Washoe County, Nevada resident in her 70s who arrived in the United States in early August 2016 after an extended visit to India. She was admitted to the acute care hospital on August 18 with a primary diagnosis of systemic inflammatory response syndrome, likely resulting from an infected right hip seroma. The patient developed septic shock and died in early September. During the 2 years preceding this U.S. hospitalization, the patient had multiple hospitalizations in India related to a right femur fracture and subsequent osteomyelitis of the right femur and hip; the most recent hospitalization in India had been in June 2016.
Antimicrobial susceptibility testing in the United States indicated that the isolate was resistant to 26 antibiotics, including all aminoglycosides and polymyxins tested, and intermediately resistant to tigecycline (a tetracycline derivative developed in response to emerging antibiotic resistance). Because of a high minimum inhibitory concentration (MIC) to colistin, the isolate was tested at CDC for the mcr-1 gene, which confers plasma-mediated resistance to colistin; the results were negative. The isolate had a relatively low fosfomycin MIC of 16 μg/mL by ETEST.* However, fosfomycin is approved in the United States only as an oral treatment of uncomplicated cystitis; an intravenous formulation is available in other countries.
Control of CRE needs to be the paramount issue
This [MMWR] report highlights three important issues in the control of CRE. First, although CRE are commonly sent to CDC as part of surveillance programs or for reference testing, isolates that are resistant to all antimicrobials are very uncommon. Among >250 CRE isolate reports collected as part of the Emerging Infections Program, approximately 80% remained susceptible to at least one aminoglycoside and nearly 90% were susceptible to tigecycline (2). Second, to slow the spread of bacteria with resistance mechanisms of greatest concern (e.g., gene encoding NDM or mcr-1) or with pan-resistance to all drug classes, CDC recommends that when these bacteria are identified, facilities ensure that appropriate infection control contact precautions are instituted to prevent transmission and that health care contacts are evaluated for evidence of transmission (3). Third, the patient in this report had inpatient health care exposure in India before receiving care in the United States. Health care facilities should obtain a history of health care exposures outside their region upon admission and consider screening for CRE when patients report recent exposure outside the United States or in regions of the United States known to have a higher incidence of CRE (1).