Notes from the Field: Detection of bla_NDM-1 Carbapenem Resistance in a Clinical Isolate of Providencia stuartii in a U.S./Coalition Medical Facility --- Afghanistan, 2011

On March 4, 2011, an isolate of Providencia stuartii obtained on January 26 from the blood of a burn patient in a U.S./coalition medical facility in Bagram, Afghanistan, was found to have the bla_NDM-1 carbapenemase gene that confers resistance to antibiotics of the carbapenem family. As with other New Delhi metallo-ß-lactamase (NDM-1)--producing strains, the isolate was resistant to carbapenems and susceptible to aztreonam, a monobactam. The patient was an Afghanistan resident transferred January 20 from a local hospital in Kabul, Afghanistan, 5 days after injury, to the intensive-care unit in Bagram for treatment of severe burns and inhalation injury caused by a natural gas explosion. At the local hospital, the patient received unspecified antibiotics, which were changed to levofloxacin, piperacillin/tazobactam, and vancomycin on arrival at Bagram. No history of prior illness or travel exposures was obtained. The patient was coinfected with a carbapenem-resistant, bla_NDM-1-- negative Pseudomonas aeruginosa, a less resistant P. aeruginosa, and Proteus mirabilis, and ultimately died from infection. This is the first report of bla_NDM-1 in P. stuartii and of this resistance mechanism within the U.S. military health-care system (MHS) and Afghanistan.

Since June 25, 2010, when three cases of Enterobacteriaceae producing NDM-1 were first described in the United States (1), NDM-1 has been reported throughout the world and among different species of bacteria. This primarily plasmid-borne metallo-ß-lactamase confers resistance to all ß-lactams, with the exception of aztreonam, and poses a serious challenge to infection control and therapy (2). Bla_NDM-1 has been reported once in Providencia species as P. rettgeri, from a patient in India (3). That strain was classified as intermediately susceptible to imipenem (or meropenem), in contrast to the P. stuartii strain, which was classified as resistant by each of three automated susceptibility testing systems.

Ongoing surveillance, effective infection control efforts, and advanced susceptibility testing of isolates offer the best chance to limit the spread of resistant nosocomial pathogens. The Multidrug-Resistant Organism Repository and Surveillance Network, an initiative of the U.S. Army Medical Command and the Walter Reed Army Institute of Research, provides these services throughout the U.S. Army. This case is an early warning to laboratories that are likely to identify carbapenem-resistant bacteria from MHS patients.

Reported by

Sherrie A. Storey, Bagram, Afghanistan; Patrick T. McGann, PhD, Emil P. Lesho, DO, Paige E. Waterman, MD, Div of Bacterial and Rickettsial Diseases, Walter Reed Army Institute of Research, Silver Spring, MD. Corresponding contributor: Paige Waterman, paige.waterman@us.army.mil, 301-319-9599.

Acknowledgments

Philip Bossart, Caitlin Alexander, Eugene Brown, Daniel Crisp, Mary Elizabeth Penny, Stephanie Washington, Paige Hargrave, Troy Thompson, Thomas Hall, Craig Joint Theater Hospital, Afghanistan. Amy Summers, Yoon Kwak, Mohamad Chahine, Multidrug-resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research.

References

1. CDC. Detection of Enterobacteriaceae isolates carrying metallo-beta-lactamase---United States, 2010. MMWR 2010;59:750.
2. Yong D, Toleman MA, Giske, CG, et al. Characterization of a new metallo-beta-lactamase gene, bla(NDM-1), and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India. Antimicrob Agents Chemother 2009;53:5046--54.
3. Nordmann P, Poirel L, Carrër A, Toleman MA, Walsh TR. How to detect NDM-1 producers. J Clin Microbiol 2011;49:718--21.