Seasonal Variation of Surgical Site Infections: Why Does It Occur, Why Does It Matter?

with MDR-E. coli at 49.2%, MDR-AB at 20.1%, MDRK. pneumoniae at 18.0%, and MDR-P. aeruginosa at 2.7%. The colonization rate for MDROs was 56.1% on day 1, and it was 73.5% by day 3, 71.4% by day 7, and 81.8% by day 14 or longer. In addition, the MDR-AB colonization rate and proportion of MDR-AB versus all MDROs isolated from the rectums of ICU patients were also positively associated with the length of stay in ICU (Table 1). We implemented a series of interventions, including enhancing the adherence to hand hygiene, disinfecting the environment using Metrex CaviWipes (Metrex) immediately after MDROs detection, and contact isolation. After interventions, the overall MDRO and MDR-AB contamination rates in the surrounding environment decreased to 10.7% and 7.1%, respectively (Table 1). Nevertheless, the overall MDRO and MDR-AB rectal colonization rates showed no significant differences (69.8% and 17.9%, respectively). These results show that contamination and colonization with MDROs, particularly MDR-AB, in the surrounding environment and rectums of ICU patients, are augmented with increasing of length of stay in ICU. The phenomenon could be explained by the spread of organisms from contaminated sites to other surfaces, the contamination of the environment by sputum, feces, blood, and body fluids from patients, and the selective pressure exerted by antibiotic use. Furthermore, Acinetobacter spp. are able to survive on inanimate surfaces for a long time, thus the proportion of MDR-AB versus all MDROs on the surrounding environmental surfaces increased with length of stay in ICU. Therefore, more efforts should be put towards the cleaning and disinfection of the surrounding environment of patients, particularly those who stay in ICU for an extended time. Conventional interventions could lead to the decontamination of MDROs on the surrounding environmental surfaces; however, these procedures will not reduce rectal colonization of gram-negative MDROs. Additional measures, including decreasing unnecessary antibiotic exposure, decontamination of the digestive tract, and chlorhexidine bathing, are needed for the decolonization of endosomatic MDROs.