Till recently, it was thought that almost all cases of Costridium difficile infections occurred inside hospitals in patients who were on antibiotics. But a new study found that more than 80 percent of patients who had tested positive for C.difficile were tested outside the hospital or within the first 72 hours of being admitted. This suggests that settings outside the hospitals may also be responsible for onset and spread of the diseases.

The Kaiser Permanente study appears Wednesday in the journal Mayo Clinic Proceedings. The study gives a new perspective to the identification of C.diff, the primary cause of infectious diarrhea, and is one of the first to accurately identify a large number of people infected with C.diff in hospitals as well as outpatient settings.

"Kaiser Permanente's integrated health care system allowed us to track patients after they left the hospital in both the outpatient health setting and during a readmission which contributed an important new perspective to the current C. diff story," said study lead author Dr. Sara Y. Tartof, of the Kaiser Permanente Southern California Department of Research & Evaluation, in a statement. "Previous studies typically focused on diagnoses during a hospital stay, which tells only part of the story. These findings emphasize how important it is to test for the infection both in the hospital as well as in outpatient settings."

The study involved examining the electronic health records of more than 268,000 Kaiser Permanente patients in Southern California, who were admitted to 14 Kaiser Permanente hospitals between Jan. 1, 2011 and Dec. 31, 2012. Of these patients, 4,286 — or 1.6 percent — tested positive for C. diff. During the study, researchers found that 49 percent of C. diff cases were acquired in the community or from an indeterminate source and that 31 percent of cases were associated with a previous hospitalization.

"C. diff infection is a major public health concern in the U.S., with infection rates tripling over the last decade," Tartof said. "This study's comprehensive view gives a more complete picture of the extent of health care-associated infections."

What makes C.diff so prevalent in medical settings is the ability of the bacterial spores to persist in the environment. A patient carrying the bacteria may release it in his surroundings and the bacteria will survive on surfaces like hand rails, bathroom fixtures, or medical equipment for months. When people visit hospitals for other medical conditions these spores may enter their bodies from the infected surfaces and cause infections.

Also, people on antibiotics are more susceptible, since some broad-spectrum antibiotics destroy not just infectious organisms but also healthy gut bacteria, which keep populations of C.diff in check. C.diff is part of the normal gut flora, but when allowed to grow unchecked, it can cause infections.

Severe diarrhea, abdominal pain, and loss of appetite are common symptoms associated with this infection. In extreme cases, it may lead to kidney failure or a hole in the intestine. The Centers for Disease Control and Prevention (CDC) reports that over the years the number of C. diff infection-related death has increased. Studies also show that C. diff infection accounts for considerable increases in the length of hospital stays and more than $1.1 billion in health care costs each year in the United States.

With the emergence of antibiotic-resistant strains, the best bet is to prevent the onset of the infection — and hospitals can play an active role in this. The CDC reports that hospitals following infection control recommendations saw C. diff infection rates reduce by 20 percent in less than two years.

"Kaiser Permanente works diligently to prevent C. diff infections in both the hospital and ambulatory settings," said Dr. Michael Kanter, regional medical director of quality and clinical analysis, Southern California Permanente Medical Group. "We promote judicious use of antibiotics, we make painstaking efforts to ensure our staff and health care providers practice hand hygiene, we prompt testing of symptomatic patients, and we conduct vigorous cleaning of rooms with special cleaning agents known to kill C. diff when patients with the infection are identified."

Source: Tartof SY, Yu KC, Wei R, Tseng HF, Jacobsen SJ, Rieg GK. Incidence of Polymerase Chain Reaction–DiagnosedClostridium difficile in a Large High-Risk Cohort, 2011-2012. Mayo Clinic Proceedings. 2014.