KPC Type β-Lactamase, Rural Pennsylvania

To the Editor: Rural counties have been defined as those lacking a metropolitan center that has a population >50,000 persons (1). Little is known about antimicrobial drug resistance in such communities in the United States. Stevenson and colleagues (2) recently evaluated antimi-crobial drug–resistant gram-positive infections in rural hospitals in Idaho and Utah. These researchers found that both methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci occurred in such settings, although some of the MRSA strains were probably community associated. Comparable studies on multidrug-resistant gram-negative infections have not been performed, to our knowledge. Klebsiella pneumoniae producing a broad-spectrum β-lactamase, KPC, has been described in tertiary care centers and other metropolitan hospitals in New York City. Examples have also been found in similar settings in Boston, New Jersey, Maryland, and North Carolina (3–5). The carbapen-ems (such as imipenem and meropen-em) are typically the most active antimicrobial agents against the Enterobacteriaceae. The KPC β-lac-tamases inactivate carbapenems and all other β-lactam antimicrobial drugs. Unfortunately, bacteria producing the KPC type β-lactamases are typically also resistant to trimetho-prim/sulfamethoxazole, quinolones, and aminoglycosides, thereby making these pathogens truly multidrug resistant. We describe a patient with KPC-producing K. pneumoniae in a rural setting in central-west Pennsylvania. The case highlights the potential for multidrug-resistant gram-negative organisms to occur outside their previously recognized settings in large metropolitan centers. The patient was a 76-year-old woman who lived alone, closely attended by her daughter, in a small, central Pennsylvania community, 95 miles from a metropolitan center with a population of >50,000. Her medical history included a seizure disorder, hypertension, osteoarthritis of the knees, obesity, osteoporosis, and total hysterectomy. A month before isolation of the KPC-producing K. pneu-moniae, the patient had a 3-day hospital admission to a 200-bed hospital in the nearest metropolitan center (population 7,000) after a fall. She was discharged to a local nursing home for rehabilitation. She is not known to have visited or been hospitalized in New York, Philadelphia, or New Jersey, nor did she share a room with a patient known to have been hospitalized in these areas. She had no known animal contact. She had received trimethoprim/sulfamethoxazole and levofloxacin for treatment for urinary tract infections in the month before the KPC-producing strain was isolated. She was readmitted to the 200-bed hospital with pyelonephritis in August 2005. Cultures of urine grew K. pneu-moniae; the organism was resistant to all β-lactam antimicrobial drugs tested , including cefepime, ceftriaxone, piperacillin/tazobactam, imipenem, fluoroquinolones, …