In this study, we conducted a comprehensive investigation of
C. difficile carriage among cancer patients from three hospitals in eastern China. The overall
C. difficile-positive rate of the cancer patients enrolled in the 7-month period was 20.5%. This rate is much higher than that (12.6%) reported in non-cancer patients in a similar study in 2009 in eastern China [
14]. The relationship between various clinical and immunological factors and
C. difficile carriage was further analyzed. Two factors (age, days of hospitalization) were determined to be significantly associated with the rate of
C. difficile carriage. First, we found that cancer patients with
C. difficile carriage appeared to be younger than patients from the U.S. [
15]. This difference could be caused by various factors, such as diet, geographical location, intake of food supplements and drugs, and other causes. Studies also have found that features of gut microbiomes are always unique to different locations and lifestyles [
16]. The lifestyles of Chinese people, especially those of young Chinese, have changed dramatically over the last 20 years, partially because of the rapid growth of the Chinese economy. The changed lifestyle which was not so common in China in the past, might be a major contributor to the increasing emergence of
C. difficile infection. Interestingly, the age predisposition was consistent with a previous study of cancer patients in Beijing, China [
17]. Meanwhile, a large scale study in Japan also revealed that long hospital stay was associated with
C. difficile infection [
18]. However, these two studies did not provide a cutoff value for age and the hospitalization days. In our study, we found that the cancer patients who were younger than 50 years old and had stayed in hospital for more than 10 days were more prone to
C. difficile carriage. It is easier to understand that longer stay in hospital exposes a higher risk of infection to patients; it is less clear to us why the younger patients in our study were more prone to
C. difficile carriage. A similar result was reported recently in northern China [
17].
Immune response is important for
C. difficile carriage. However, among white blood cell count, albumin count, and levels of PGE2, TGF-β, and IL-10, which are thought to be inhibitors of immunological activity [
19], we found no factor was related to the
C. difficile-positive rate. And ribotyping of
C. difficile showed that there was no 027 strain, which was the major cause of the deadly
C. difficile infection emergence in Canada between 2002 and 2005 [
20].
Strikingly, more than 90% of the
C. difficile-positive cancer patients in our study had no symptoms of diarrhea. The reason might be complicated. A similar study also showed no outbreak of
C. difficile infection despite
C. difficile carriage [
21]. Nevertheless, researchers have suggested that asymptomatic carriers can contribute to
C. difficile transmission in hospitals [
22]. As a result of the near-indefinite viability of the bacteria and the low infective dose,
C. difficile could be widely transmitted within hospitals in the presence of the ever increasing asymptomatic carriers [
23].