By Gary Evans, Medical Writer 

With the difficult and ongoing struggle against Clostridium difficile — a nasty spore-former that kills some 15,000 patients annually — a 7% reduction from 2015 to 2016 in national infection rates is certainly a move in the right direction. But there is more to the story than this incremental decline in healthcare-associated C. diff infections.

The epidemiology of C. diff is changing. While healthcare-associated cases are declining, more cases are coming in from the community. Some suspect that hospitals are doing more testing on admission to ensure that patients who come in with C. diff are not later counted as hospital-acquired. Although that protects the hospital from financial penalties, a concern is that highly sensitive tests may be picking up mere C. diff colonization, which may then be counted as community-associated cases of actual infections.

Although these factors are probably affecting the shift in numbers, the primary driver of the increase in C. diff in the community is likely antibiotic use beyond the hospital, said a leading medical epidemiologist at the Centers for Disease Control and Prevention.

“I think it’s real,” Arjun Srinivasan, MD, FSHEA, FAPIC, told Hospital Infection Control & Prevention. “Clearly, there are some people who get tested without clear symptoms — they only have diarrhea — but the concern is that the outpatient cases we are seeing probably reflect antibiotic use. We know that there is a lot of fluoroquinolone use in outpatient settings — an antibiotic that is one of the highest risks for C. diff.”

It is well known that fluoroquinolones and other broad spectrum antibiotics can disrupt the gut microbiome and set up a C. diff infection. That suggests that these community-onset cases, which have no recent history of hospitalization, received antibiotics after visiting a doctor, dental office, or clinic. Another factor that may be contributing to the trend is that antibiotic stewardship programs are being heavily emphasized in hospitals but may still be in more rudimentary stages in community care.

In presenting a session on C. diff and other hospital infections in Minneapolis at the annual conference of the Association for Professionals in Infection Control and Epidemiology (APIC), Srinivasan cited data collected by 10 CDC Emerging Infection Program (EIP) sites nationally.

“We are actually seeing decreases in healthcare-associated C. diff, but we are seeing increases in cases of C. diff that have community onset,” he told APIC attendees. “This is a really important distinction that we are seeing.”

Indeed, data from the EIP sites show that the healthcare-associated C. diff rate per 100,000 people fell from 93 cases in 2012 to 83 cases in 2015. Conversely, community-associated C. diff by that same population measure went from 53 cases in 2012 to 66 cases in 2015.