Decrease in airborne colony-forming units linked with fewer implant-related infections

Investigators found a significant relationship between colony-forming unit density at incision sites and incidence of implant infection.

Recently published results showed a reduction in airborne colony-forming units during operations may effectively reduce the number of prosthesis-related infections, specifically at the incision site.

“Contamination with microorganisms in the operating room is not uncommon,” study researcher Rabih O. Darouiche, MD, told Orthopedics Today. “Colony-forming unit (CFU) contamination of air in the incision site is a risk factor for implant-related infections. Decrease in the presence of CFUs in the operating room has the power of minimizing infection.”

Implant, incision infection

Rabih O. Darouiche, MD
Rabih O. Darouiche

Darouiche and his colleagues randomly assigned 300 patients who were undergoing total hip arthroplasty, instrumented spinal procedures or vascular bypass graft implantation to either an intervention or control group. According to researchers, all operations assigned to the intervention group were performed using the Air Barrier System device (Nimbic Systems) to protect against airborne CFUs and particulates at the incision site, while operations assigned to the control group were performed without the Air Barrier System device. To determine whether airborne CFU levels at the incision sites predicted the incidence of incisional or prosthesis-related infection, researchers followed patients for 12 months.

Results showed significantly lower particulate and CFU densities among the intervention group, with 68.1% of the 10-minute surgical intervals collected in the intervention group during the study revealing 0 CFU/m3 vs. 46.1% in the control group. Although researchers noted a significant relationship between CFU density at incision sites to the incidence of implant infection, there was no relationship with incisional infection. According to results, procedures with implant infection had airborne CFU densities four-times greater vs. procedures with no implant infection. Overall, researchers found four implant infections in the control group vs. zero in the intervention group.

“We did anticipate that the use of the [Air Barrier System] ABS would result in a decrease in the occurrence of implant-related infections, but were a bit surprised as to why there was no impact on the occurrence of incisional infections,” Darouiche said. “However, it is possible that implementation of optimal skin preparation for all enrolled patients was overwhelmingly protective against infection.”

Protective approaches

According to Darouiche, the next step includes a large multicenter study of 900 patients across three medical centers, which could lead to protective approaches to surgery.

“Unfortunately, the rate of implant-related infections is not as low as it should be across the country,” Darouiche said. “Hence, the major need for developing and assessing potentially protective approaches.” – by Casey Tingle

Disclosure: The study was sponsored by the NIH. Darouiche reports he receives grants from the NIH and was director of the annual educational meetings of the Multidisciplinary Alliance Against Device-Related Infection, which received educational funds from Nimbic Systems, the manufacturer of Air Barrier System.

Recently published results showed a reduction in airborne colony-forming units during operations may effectively reduce the number of prosthesis-related infections, specifically at the incision site.

“Contamination with microorganisms in the operating room is not uncommon,” study researcher Rabih O. Darouiche, MD, told Orthopedics Today. “Colony-forming unit (CFU) contamination of air in the incision site is a risk factor for implant-related infections. Decrease in the presence of CFUs in the operating room has the power of minimizing infection.”

Implant, incision infection

Rabih O. Darouiche, MD
Rabih O. Darouiche

Darouiche and his colleagues randomly assigned 300 patients who were undergoing total hip arthroplasty, instrumented spinal procedures or vascular bypass graft implantation to either an intervention or control group. According to researchers, all operations assigned to the intervention group were performed using the Air Barrier System device (Nimbic Systems) to protect against airborne CFUs and particulates at the incision site, while operations assigned to the control group were performed without the Air Barrier System device. To determine whether airborne CFU levels at the incision sites predicted the incidence of incisional or prosthesis-related infection, researchers followed patients for 12 months.

Results showed significantly lower particulate and CFU densities among the intervention group, with 68.1% of the 10-minute surgical intervals collected in the intervention group during the study revealing 0 CFU/m3 vs. 46.1% in the control group. Although researchers noted a significant relationship between CFU density at incision sites to the incidence of implant infection, there was no relationship with incisional infection. According to results, procedures with implant infection had airborne CFU densities four-times greater vs. procedures with no implant infection. Overall, researchers found four implant infections in the control group vs. zero in the intervention group.

“We did anticipate that the use of the [Air Barrier System] ABS would result in a decrease in the occurrence of implant-related infections, but were a bit surprised as to why there was no impact on the occurrence of incisional infections,” Darouiche said. “However, it is possible that implementation of optimal skin preparation for all enrolled patients was overwhelmingly protective against infection.”

Protective approaches

According to Darouiche, the next step includes a large multicenter study of 900 patients across three medical centers, which could lead to protective approaches to surgery.

“Unfortunately, the rate of implant-related infections is not as low as it should be across the country,” Darouiche said. “Hence, the major need for developing and assessing potentially protective approaches.” – by Casey Tingle

Disclosure: The study was sponsored by the NIH. Darouiche reports he receives grants from the NIH and was director of the annual educational meetings of the Multidisciplinary Alliance Against Device-Related Infection, which received educational funds from Nimbic Systems, the manufacturer of Air Barrier System.