Escherichia coli and Klebsiella pneumoniae carbapenemase in long-term care facility, Illinois, USA.

To the Editor: Escherichia coli harboring Klebsiella pneumoniae carbapenemases (KPCs) are now rarely being reported. Worldwide, KPC-2 has been detected in Israel and the People’s Republic of China (,). Within the United States, carbapenem-resistant E. coli carrying blaKPC has been isolated in New Jersey () and Cleveland, Ohio (), and 7 carbapenem-resistant E. coli isolates were obtained from 3 different hospitals in Brooklyn, New York (). Urban et al. () recently reported 9 KPC-2 and KPC-3 carbapenemases in urinary E. coli isolates from 7 long-term care facilities. We report such an isolate from a resident of a long-term care facility.

This case involved a 68-year-old female resident of a long-term care facility in Centralia, Illinois, who had multiple chronic medical problems, including cerebral palsy, a seizure disorder, and recurrent urinary tract infections. A urine culture grew >105 CFU/mL of E. coli susceptible to amikacin, gentamicin, tobramycin, piperacillin/tazobactam, trimethoprim/sulfamethoxazole, imipenem, and nitrofurantoin. Tigecycline susceptibility was not determined. Trimethoprim/sulfamethoxazole therapy was initiated. Follow-up urine culture almost 3 weeks later again grew >105 CFU/mL of E. coli, now susceptible to amikacin, gentamicin, tobramycin, nitrofurantoin, and tigecycline. The isolate was resistant to imipenem and meropenem. A modified Hodge test demonstrated production of a carbapenemase (), and the blaKPC gene was detected by PCR at the Centers for Disease Control and Prevention (CDC). The patient was treated with a 10-day course of nitrofurantoin, 100 mg by gastrostomy tube 2× per day. Chart review indicated that contact precautions were instituted only after discovery of the second E. coli isolate.

Seventeen days later, a repeat urine culture grew >105 CFU/mL of K. pneumoniae susceptible only to amikacin, gentamicin, tobramycin, and tigecycline. No treatment was given. Follow-up urine culture grew >105 CFU/mL of K. pneumoniae again with a similar resistance pattern. The modified Hodge test result was positive () and was confirmed as blaKPC positive by PCR at CDC. The resident was transferred to an acute care facility for further evaluation and was treated with amikacin. At completion of therapy, a repeat urine culture was negative for organisms.

Our case, like that of Urban et al. (), involved a urinary isolate from a resident of a long-term care facility. As increasing numbers of resistant gram-negative rods colonize such patients, the patients may acquire a bacterium carrying a KPC plasmid conferring broad-spectrum resistance as described in our patient. These plasmids may then be laterally transferred to other gram-negatives, which may have occurred in this case.

Our case underscores the gravity of the evolutionary process of emergent, multidrug–resistant enterobacteriaceae. Even though E. coli strains that harbor carbapenemase genes are not ubiquitous, additional therapeutic interventions are needed to prevent the spread of these bacteria, which are likely to infect increasing numbers of patients.