A woman from Washoe County, Nevada, was diagnosed in a Reno acute care hospital with a form of Carbapenem-resistant Enterobacteriaceae (CRE) that was resistant to all antibiotics available in the United States, according to a report published in the January 13 issue of the Morbidity and Mortality Weekly Report.
The Centers for Disease Control and Prevention (CDC) confirmed the presence of New Delhi metallo-β-lactamase (NDM) in the CRE isolate taken from the patient.
Antimicrobial susceptibility testing showed that the Klebsiella pneumoniae isolate was resistant to 26 antibiotics, including all aminoglycosides and polymyxins tested. It was intermediately resistant to tigecycline, a tetracycline derivative designed to counteract antibiotic resistance.
Further testing showed that although the strain was resistant to colistin, it did not carry the mcr-1 gene, which is known to confer colistin resistance and has been reported in other pan-resistant strains.
"The isolate had a relatively low fosfomycin [minimum inhibitory concentration].... However, fosfomycin is approved in the United States only as an oral treatment of uncomplicated cystitis; an intravenous formulation is available in other countries," write Lei Chen, PhD, from the Washoe County Health District, and colleagues.
History of Hospitalization Outside of the United States
The patient, a 70-year-old woman, arrived in the United States in August 2016 after a long period in India. She was admitted to the hospital on August 18, 2016, with "a primary diagnosis of systemic inflammatory response syndrome, likely resulting from an infected right hip seroma."
During the 2 previous years, she had been hospitalized many times in India related to a right femur fracture, the last time in June 2016. Hospitalization outside the United States is a known risk factor for NDM, according to the CDC.
The bacterial isolate was taken from a wound specimen on August 19, 2016, and sent to the CDC because of the patient's travel history.
"After CRE was identified, the patient was placed in a single room under contact precautions," the authors write. The patient developed septic shock and died in early September.
Ongoing surveillance in Washoe County has not uncovered any further cases of NDM-CRE. Moreover, rectal swabs from patients who were in the same unit with the woman were all negative for CRE.
Case Highlights CRE Control Issues
As previously reported by Medscape Medical News, CREs represent an urgent threat in the United States because they are linked to death rates as high as 50%, there are few effective treatments, and they can spread rapidly.
An important issue highlighted by this case is that isolates that show resistance to all antimicrobials are not common. Of more than 250 CRE samples collected in the Emerging Infections Program, about 80% were vulnerable to at least 1 aminoglycoside; 90% were susceptible to tigecycline.
However, the CDC reports that as of January 6, 2017, a total of 175 patients in the United States have been diagnosed with NDM-CRE, 81 of them in Illinois.
The CDC recommends that when such bacteria are identified, healthcare facilities should use infection control contact precautions and make sure any providers who have contact with the patient are checked for transmission.
Medscape adviser and infectious disease expert Paul G. Auwaerter, MD, says in a video commentary posted on Medscape that NDM cases are coming out of China and India and spreading quickly around the globe.
That highlights another lesson for hospitals, Dr Chen and colleagues write: At admission, providers should get a history of healthcare encounters outside the immediate area "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," they write.
The authors have disclosed no relevant financial relationships.
Morb Mortal Wkly Rep. 2017;66:33. Full text