SURGICAL INFECTIONS Volume 15, Number 1, 2014 ª Mary Ann Liebert, Inc. DOI: 10.1089/sur.2012.119
Effectiveness of N-Butyl Cyanoacrylate-Based Microbial Skin Sealant on the Prevention of Surgical Site Infections Mustafa Tahir Ozer,1 Huseyin Sinan,2 Mehmet Saydam,2 Abdullah Kilic,3 Mesut Akyol,4 Ali Kagan Coskun,1 Orhan Bedir,3 and Sezai Demibas1
ABSTRACT
Background: Surgical site infections (SSIs) are a serious concern in health care, and wound contamination by endogenous skin flora is a major factor in the development of SSIs. Despite preventive tactics in pre-operative skin care, antibiotic prophylaxis, surgical technique, and post-operative incision care, complete sterilization of the skin is not possible. Recently developed microbial skin sealant forms a continuous but breathable barrier that prevents migration of endogenous skin flora into the incision. The skin sealant closes dermal microabrasions, preventing re-colonization of potential pathogens at the incision. The purpose of this study was to determine the effect of an N-butyl cyanoacrylate-based microbial skin sealant in reducing the occurrence of SSIs in an experimental rodent model. Methods: This was a randomized, controlled animal trial. Forty-eight Wistar albino rats were divided into six groups of eight rats each. Three groups received application of sealant against specific bacteria, and three matched control groups received only the bacteria without the sealant. Group one underwent pre-operative hair removal, followed by application of skin sealant, then abdominal incision and closure. Group two (control) simply underwent hair removal, followed by incision and closure, with no skin sealant applied. Group three received an application of cage swabs (containing a mixture of urine, stool and sawdust from the animals’ cages) before application of skin sealant, and group four (control) received cage swabs without subsequent skin sealant. Group five received methicillin-resistant Staphylococcus aureus (MRSA) followed by skin sealant, and group six (control) received MRSA without skin sealant. Seven days after surgery, the animals were sacrificed. Samples were taken from the abdomen of each rat and placed in culture medium. Proliferation of the following bacteria were observed: Coagulase-negative staphylococci (CoNS), gram-positive bacilli (GPB), Pseudomonas aeruginosa, and MRSA. Results: There was a statistically significant difference between the median number of GPB in the group that received cage swabs + sealant and the group that received cage swabs without sealant (median, GPB count 29,430 colony-forming units [CFU]/g vs 359,100 colony-forming units [CFU]/g; p < 0.05). The study results showed that microbial skin sealant was not as effective in preventing CoNS or MRSA contamination as it was in preventing GPB contamination. Conclusions: Use of a microbial skin sealant before surgery can lower the rate of SSIs by reducing the migration of some specific bacterial agents. Additional data are needed to validate its use in clinical practice.
S
ing surgery. The period of infection may extend up to 1 y if an implant is used [1]. Surgical site infections are the form of nosocomial infection encountered most commonly in surgical patients [2,3]. A number of preventive measures, including optimization of host defenses, pre-operative skin care tactics, hand hygiene, antibiotic prophylaxis, operating room
urgical site infections (SSIs) remain a serious concern in health care. A SSI is an infection that develops as a result of a surgical incision, manifested by pus or a swab with >105 colony-forming units (cfu) per mm3 tissue and at least one of the following signs or symptoms: Pain, localized swelling, redness, or heat, and occurring within 30 d follow-
1 Department of General Surgery, 3Department of Microbiology, 4Department of Biostatistics, Gulhane Military Medical Academy, Ankara, Turkey. 2 Department of General Surgery, Ankara Mevki Military Hospital, Ankara Turkey.
14
MICROBIAL SKIN SEALANT ON SSI management, asepsis, surgical technique, minimization of local injury through surgery, and post-operative incision care, should be emphasized in the practice of surgery to reduce the rate of SSIs [4,5]. Wound contamination by endogenous skin flora is a major factor in the development of SSIs. The pathogens involved most commonly are gram-positive cocci, gram-negative organisms, and, less commonly, anaerobes. Anti-sepsis of the skin is an important factor in reducing the concentrations of bacteria at operative sites. Yet, despite all these preventive tactics, complete sterilization of the skin is not possible [6–8]. The microbial skin sealant is an N-butyl cyanoacrylatebased liquid that polymerizes on application to form a continuous but breathable barrier that prevents migration of endogenous skin flora into the incision. Beyond what other skin preparations can do, the microbial sealant can close microabrasions on the skin, hence, preventing re-colonization of any potential pathogens at the areas of interest. Another important feature of a microbial sealant is that it prevents further bacterial resistance [9]. The purpose of this study was to determine the effect of an n-butyl cyanoacrylate-based microbial skin sealant (Integuseal, Kimberly-Clark Health Care, Roswell, GA) in reducing the occurrence of SSIs after surgery. Methods Study design The study was designed as a prospective, controlled animal trial. Statistical calculations were performed using Random Allocation Softwareª Ver. 1.0.0 (Mahmood Saghaei, Isfahan, Iran). The experimental protocol was designed according to the ’’Guiding Principles in the Care and Use of Animals’’ approved by the Council of the American Physiological Society, and was approved by the local ethics committee on animal use (Ethic-2009/24; decision date and number: 22 May 2009- 09/39K). Power and sample size Determination of the study sample size and the power calculation were performed with G * Power (Ver. 3.0.10, Franz FAUL, Universita¨t Kiel, Germany). Calculations showed that in order to achieve 80% power to effect a width of f = 0.30, a = 0.05 Type I error, and b = 0.20 Type II error rates, a total of 42 rats would be needed, divided into six groups containing at least seven rats. Due to the length of the followup period, it was determined that one replacement rat should be added to each group (i.e., eight rats per group); therefore, the total number of study subjects was 48 rats. Study procedure Forty-eight Wistar albino rats (180–220 g) were used in the study. The rats were divided into six groups. The animals scheduled for surgical procedures in each group had their abdominal hair removed by a clipper before the pre-operative measurements and abdominal incision. Because we investigated the limits of Integuseal, we did not use standard skin disinfection (e.g., povidone-iodine, isopropyl alcohol). In the eight rats in the first group, the anti-microbial skin sealant was applied to the abdomen one minute after abdominal hair removal and 5 min before the abdominal incision. No attempt was made to sterilize the region after the application of the skin
15 sealant; the region was assumed to be sterile. As in clinical practice, sterile conditions and disposable sterile gloves were provided for surgery. After incision, the abdomen was closed in accordance with standard procedures. All of the incisions were made by disposable lancets. In the eight rats in the second (control) group, the only pre-operative skin preparation was hair removal; 5 min after hair removal, the abdominal incision was made, and then closure was performed. In the eight rats in the third group, cage swabs were applied to the abdominal skin one minute after pre-operative hair removal and 1 min before the microbial skin sealant was applied. The abdominal incision was made 5 min after the microbial skin sealant was applied, after which closing was performed. In the eight rats in the fourth (control) group, cage swabs were applied one minute after hair removal; then, 5 min after application of the cage swabs, the abdominal incision was made, followed by closure. In the eight rats in the fifth group, methicillin-resistant Staphylococcus aureus (MRSA) was applied to the abdominal skin one minute after hair removal. One minute after application of the MRSA, microbial skin sealant was applied. Five minutes after application of the microbial skin sealant, the abdominal incision was made, followed by closure. To the eight rats in the sixth (control) and last group, MRSA culture was applied to the abdominal skin 1 min after hair removal. Five minutes after application of the MRSA, the abdominal incision was made, followed by closure. Preparation of the cage swabs The combination of urine, sawdust, and stool of the animals housed in cages was mixed in tap water. One hour later, a liquid suspension was obtained by filtering the solid particles. The composition of the liquid suspension was analyzed by microbiologic techniques. Coagulase-negative Staphylococcus (CoNS) and gram-positive bacillus (GPB) bacteria were detected. All materials were manipulated with sterile swabs. Preparation of the MRSA inoculum The MRSA inoculum was prepared by our hospital’s microbiology department. Statistical Analysis Descriptive statistics, together with the observed number and percentage of the median for the number of bacteria, were shown as (min-max) CFU/g. The Mann-Whitney U test was used to determine the impact of skin sealant on the median number of bacteria in the experimental groups. Statistical analysis and calculations were performed with SPSS for Windows Ver. 15.0 (SPSS Inc., Chicago, IL). Statistical significance was accepted at the level of p £ 0.05. Results At the beginning of the study, eight rats had been assigned to each trial group. However, after the 7-d follow-up period, one rat in the skin sealant group (first group) and two rats in the control group (second group) expired; therefore, the study was completed with a total of 45 rats instead of the planned 48 rats. The skin sealant is known to remain on human skin a maximum of 5–7 d. Because there has been no previous animal experimental work on this subject, we deemed it sufficient in
n
%
n
%
Total
Skin sealant Control CS + skin sealant CS MRSA + skin sealant MRSA
5 6 0 5 8 8 32
71.4 100.0 0 62.5 100.0 100.0 71.1
2 0 8 3 0 0 13
28.6 0 100.0 37.5 0 0 28.9
7 6 8 8 8 8 45
CS = cage swabs; MRSA = methicillin-resistant Staphylococcus aureus.
N/A N/A N/A N/A 465.90 (80.15– 1014.00) 4,317.09 ( 6.18–7,875.00) 0/7 0/6 0/8 0/8 8/8 8/8 16/45 N/A N/A N/A N/A N/A 2,629.20 (758.40–4,500.00) 0/ 7 0/ 6 0/ 8 0/ 8 0/ 8 2/ 8 2/45 (50.40– 50.40) ( 9.35–1,832.00) (20.25– 38.60) (27.15–3,780.00) (96.18– 138.75) N/A 50.40 11.44 29.43* 359.10* 117.47 1/ 7 3/ 6 2/ 8 6/ 8 2/ 8 0/ 8 14/45 (8.96–672.00) (1.87–707.00) (2.12– 27.36) (5.46–132.80) N/A N/A 29.55 29.75 8.05 40.20
+/ n Median (min–max) +/ n
Median (min–max)
+/ n
PA GPB
*The difference between the median GPB counts of the CS and CS + skin sealant groups is statistically significant. CoNS = coagulase-negative staphylococci; CS = cage swabs; GPB = gram-positive bacillus; PA = Pseudomonas aeruginosa; MRSA = methicillin-resistant Staphylococcus aureus; N/A = not available.
1 2 3 4 5 6 Total
Group Type
7/ 7 6/ 6 8/ 8 4/ 8 0/ 8 0/ 8 25/45
Group #
Negative
Skin sealant Control CS + Skin sealant CS (control) MRSA + Skin sealant MRSA (control) Total
Positive
Median (min–max)
Bacterial Proliferation
+/ n
Table 1. The Results of the Trial Groups of Bacteria Culture
Group
Surgical site infection is a serious potential complication of surgery that, with its high association with morbidity and mortality, leads to prolonged hospitalization, repeated surgical procedures, and increased healthcare cost [10–13].
CoNS
Discussion
Table 2. Bacteria Observed in Tissue Samples of Trial Groups (Shown as Values* 10 - 3 CFU/g)
the present study to obtain samples through the seventh day, as in human beings. Considering that it was not possible to create sterile conditions for 7 d and assuming that all the animals were kept under standard conditions, we believed it was not necessary to obtain an extra sample beyond the seventh day. After the 7-d follow-up period, the rats were sacrificed. Using standard microbiologic techniques, equal amounts of culture samples were taken from the abdominal region of each rat, and placed in culture medium. After allowing sufficient time for the growth of bacteria, the bacterial counts in each group were analyzed. Bacterial growth was observed in five (71.4%) of the seven rats in the skin sealant group (first group) and in all six rats in the control group (second group). Table 1 shows the amount of bacteria observed in each experimental group. Table 2 shows the bacterial growth in the tissue samples from the study groups. Coagulase-negative staphylococci were found in all control samples, and in the skin sealant, cage swab (CS), and CS + skin sealant groups, but CoNS was not detected any of the samples of the MRSA and MRSA + skin sealant groups. Skin sealant growth was observed in one-half the samples of the CS group, but the other half of the samples in the CS group had no CoNS growth. No statistically significant differences were found in the median number of bacteria between the groups that did or did not receive skin sealant, with the exception of the median number of GPB between the CS and CS + skin sealant groups (p < 0.05). The median GPB count in the CS group was 359 100 cfu/g, while the CS + skin sealant group had a median GPB count of 29,430 CFU/g. This difference in the median GPB count between the CS and CS + skin sealant groups was statistically different (Z = 2.356; p = 0.028). Application of skin sealant prevented growth of GPB transmitted by cage swabs, yielding statistically significant and, therefore, successful results. Although statistically significant differences between the skin sealant group and its control groups were not found with respect to GPB count, the observed GPB sample rate decreased from 3/6 to 1/7. Skin sealant is therefore also effective against GPB, but not against GPB and MRSA together.
Median (min–max)
OZER ET AL.
MRSA
16
MICROBIAL SKIN SEALANT ON SSI Thus, in our trial, we used a cyanoacrylate-based microbial sealant to determine its additional effect on prevention of wound contamination during surgery. Our study results showed that the rats treated with microbial sealant prior to skin incision had a lower rate of wound contamination that lasted for the duration of the 7-d follow-up period. The surgical incisions of the rats in the microbial sealant groups remained more sterile than those of the control groups. No statistically significant differences were found in the median number of bacteria between the groups and controls with respect to the different kinds of bacteria, with the exception of a statistically significant difference in the median number of GPB bacteria between the CS and CS + skin sealant groups (p < 0.05). The median GPB count was statistically different between the CS and CS + skin sealant groups (Z = 2.356; p = 0.028). We nevertheless determined that skin sealant was effective in all the other groups against the growth of GPB bacteria, although not against GPB and MRSA together. Our study showed that skin sealant was not as effective in preventing CoNS or MRSA bacterial contamination as it was in preventing GPB contamination. Our study has some limitations. First, we compared only superficial incisional SSIs within a 7-d follow-up period; it is possible that a longer follow-up period may have yielded different results. Second, the difficulties of keeping a wound sterile in animals are substantial, compared with patients. Third, because our study was an animal trial, all of the rats had similar risk factors. Another limitation is that we did not perform skin disinfection procedures before skin sealant application. Further studies to undertake more detailed characterization and risk factors of patients, longer follow-up duration, and sampling from incision sites before, during, and after surgery, with and without skin sealant, are needed to confirm the impact of this innovative pre-operative skin care strategy on SSI rates in clinical practice. A randomized clinical study to determine the efficacy of microbial skin sealant was conducted by Towfigh et al. [14]. Patients who underwent open, clean inguinal hernia repair and received microbial skin sealant after 10% povidone-iodine followed by iodine skin preparation had a significantly lower rate of surgical site contamination than patients treated with povidone-iodine alone (53.0 % vs. 68.7%; p = 0.04) (14). There have been a few studies that reported significant beneficial effects of microbial skin sealant on reducing the incidence of SSI. Dohmen et al. [15] conducted a case-control experiment demonstrating that the use of a microbial skin sealant prior to surgery could reduce the rate of SSI among patients undergoing cardiac surgery. In conclusion, the present study showed that the use of a microbial skin sealant prior to surgery could reduce the rate of SSI by its effect of reducing the migration of some specific bacterial agents. There were no cases of skin sensitivity or other reaction following application of the microbial sealant. We believe that skin sealant may be a new and innovative preoperative skin care strategy to minimize bacterial contamination of surgical incisions. However, further data are needed to validate its use in clinical practice. Acknowledgments The authors thank Marilyn Carlson for her editorial assistance.
17 Author Disclosure Statement No competing financial interests exist. References 1. Mangram AJ, Horan TC, Pearson ML, et al. Guidelines for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee. Infect Control Hosp Epidemiol 1999;20:250–278. 2. Edwards PS, Lipp A, Holmes A. Preoperative skin antiseptics for preventing surgical wound infections after clean surgery. Cochrane Database Syst Rev 2004;CD003949 3. Homer-Vanniasinkam S. Surgical site and vascular infections: Treatment and prophylaxis. Int J Infect Dis 2007;11:S17–S22. 4. Bratzler DW, Hunt DR. The surgical infection prevention and surgical care improvement projects: National initiatives to improve outcomes for patients having surgery. Clin Infect Dis 2006;43:322–330. 5. Dimick JB, Pronovost PJ, Cowan JA, Lipsett PA. Complications and costs after high-risk surgery: Where should we focus quality improvement initiatives? J Am Coll Surg 2003;196:671–678. 6. Dohmen PM, Weymann A, Holinski S, et al. Use of an antimicrobial skin sealant reduces surgical site infection in patients undergoing routine cardiac surgery. Surg Infect (Larchmt) 2011;12:475–481. 7. Von Eckardstein AS, Lim CH, Dohmen PM, et al. A randomized trial of skin sealant to reduce the risk of incision contamination in cardiac surgery. Ann Thorac Surg 2011;92: 632–637. 8. Dohmen PM. Antibiotic resistance in common pathogens reinforces the need to minimise surgical site infections. J Hosp Infect 2008;70:15–20. 9. Wilson SE. Microbial sealing: A new approach to reducing contamination. J Hosp Infect 2008;70:11–14. 10. Salehi Omran A, Karimi A, Ahmadi SH, et al. Superficial and deep sternal wound infection after more than 9000 coronary artery bypass graft (CABG): Incidence, risk factors and mortality. BMC Infect Dis 2007;7:112. 11. Fry DE. The economic costs of surgical site infection. Surg Infect (Larchmt) 2002;3:S37–S43. 12. Dohmen PM, Gabbieri D, Weymann A, et al. A retrospective non-randomized study on the impact of INTEGUSEAL, a preoperative microbial skin sealant, on the rate of surgical site infections after cardiac surgery. Int J Infect Dis 2011;15: 395–400. 13. Ga˚rdlund B. Postoperative surgical site infections in cardiac surgey–an overwiev of preventive measures. APMIS 2007;115: 989–995. 14. Towfigh S, Cheadle WG, Lowry SF, et al. Significant reduction in incidence of wound contamination by skin flora through use of microbial sealant. Arch Surg 2008;143:885–891. 15. Dohmen PM, Gabbieri D, Weymann A, et al. Reduction in surgical site infection in patients treated with microbial sealant prior to coronary artery bypass graft surgery: A casecontrol study. J Hosp Infect 2009;72:119–126.
Address correspondence to: Dr. Mehmet Saydam Department of General Surgery Ankara Mevki Military Hospital Ankara, Turkey 06110 E-mail: [email protected]
Effectiveness of N-Butyl Cyanoacrylate-Based Microbial Skin Sealant on the Prevention of Surgical Site Infections Mustafa Tahir Ozer,1 Huseyin Sinan,2 Mehmet Saydam,2 Abdullah Kilic,3 Mesut Akyol,4 Ali Kagan Coskun,1 Orhan Bedir,3 and Sezai Demibas1
ABSTRACT
Background: Surgical site infections (SSIs) are a serious concern in health care, and wound contamination by endogenous skin flora is a major factor in the development of SSIs. Despite preventive tactics in pre-operative skin care, antibiotic prophylaxis, surgical technique, and post-operative incision care, complete sterilization of the skin is not possible. Recently developed microbial skin sealant forms a continuous but breathable barrier that prevents migration of endogenous skin flora into the incision. The skin sealant closes dermal microabrasions, preventing re-colonization of potential pathogens at the incision. The purpose of this study was to determine the effect of an N-butyl cyanoacrylate-based microbial skin sealant in reducing the occurrence of SSIs in an experimental rodent model. Methods: This was a randomized, controlled animal trial. Forty-eight Wistar albino rats were divided into six groups of eight rats each. Three groups received application of sealant against specific bacteria, and three matched control groups received only the bacteria without the sealant. Group one underwent pre-operative hair removal, followed by application of skin sealant, then abdominal incision and closure. Group two (control) simply underwent hair removal, followed by incision and closure, with no skin sealant applied. Group three received an application of cage swabs (containing a mixture of urine, stool and sawdust from the animals’ cages) before application of skin sealant, and group four (control) received cage swabs without subsequent skin sealant. Group five received methicillin-resistant Staphylococcus aureus (MRSA) followed by skin sealant, and group six (control) received MRSA without skin sealant. Seven days after surgery, the animals were sacrificed. Samples were taken from the abdomen of each rat and placed in culture medium. Proliferation of the following bacteria were observed: Coagulase-negative staphylococci (CoNS), gram-positive bacilli (GPB), Pseudomonas aeruginosa, and MRSA. Results: There was a statistically significant difference between the median number of GPB in the group that received cage swabs + sealant and the group that received cage swabs without sealant (median, GPB count 29,430 colony-forming units [CFU]/g vs 359,100 colony-forming units [CFU]/g; p < 0.05). The study results showed that microbial skin sealant was not as effective in preventing CoNS or MRSA contamination as it was in preventing GPB contamination. Conclusions: Use of a microbial skin sealant before surgery can lower the rate of SSIs by reducing the migration of some specific bacterial agents. Additional data are needed to validate its use in clinical practice.
S
ing surgery. The period of infection may extend up to 1 y if an implant is used [1]. Surgical site infections are the form of nosocomial infection encountered most commonly in surgical patients [2,3]. A number of preventive measures, including optimization of host defenses, pre-operative skin care tactics, hand hygiene, antibiotic prophylaxis, operating room
urgical site infections (SSIs) remain a serious concern in health care. A SSI is an infection that develops as a result of a surgical incision, manifested by pus or a swab with >105 colony-forming units (cfu) per mm3 tissue and at least one of the following signs or symptoms: Pain, localized swelling, redness, or heat, and occurring within 30 d follow-
1 Department of General Surgery, 3Department of Microbiology, 4Department of Biostatistics, Gulhane Military Medical Academy, Ankara, Turkey. 2 Department of General Surgery, Ankara Mevki Military Hospital, Ankara Turkey.
14
MICROBIAL SKIN SEALANT ON SSI management, asepsis, surgical technique, minimization of local injury through surgery, and post-operative incision care, should be emphasized in the practice of surgery to reduce the rate of SSIs [4,5]. Wound contamination by endogenous skin flora is a major factor in the development of SSIs. The pathogens involved most commonly are gram-positive cocci, gram-negative organisms, and, less commonly, anaerobes. Anti-sepsis of the skin is an important factor in reducing the concentrations of bacteria at operative sites. Yet, despite all these preventive tactics, complete sterilization of the skin is not possible [6–8]. The microbial skin sealant is an N-butyl cyanoacrylatebased liquid that polymerizes on application to form a continuous but breathable barrier that prevents migration of endogenous skin flora into the incision. Beyond what other skin preparations can do, the microbial sealant can close microabrasions on the skin, hence, preventing re-colonization of any potential pathogens at the areas of interest. Another important feature of a microbial sealant is that it prevents further bacterial resistance [9]. The purpose of this study was to determine the effect of an n-butyl cyanoacrylate-based microbial skin sealant (Integuseal, Kimberly-Clark Health Care, Roswell, GA) in reducing the occurrence of SSIs after surgery. Methods Study design The study was designed as a prospective, controlled animal trial. Statistical calculations were performed using Random Allocation Softwareª Ver. 1.0.0 (Mahmood Saghaei, Isfahan, Iran). The experimental protocol was designed according to the ’’Guiding Principles in the Care and Use of Animals’’ approved by the Council of the American Physiological Society, and was approved by the local ethics committee on animal use (Ethic-2009/24; decision date and number: 22 May 2009- 09/39K). Power and sample size Determination of the study sample size and the power calculation were performed with G * Power (Ver. 3.0.10, Franz FAUL, Universita¨t Kiel, Germany). Calculations showed that in order to achieve 80% power to effect a width of f = 0.30, a = 0.05 Type I error, and b = 0.20 Type II error rates, a total of 42 rats would be needed, divided into six groups containing at least seven rats. Due to the length of the followup period, it was determined that one replacement rat should be added to each group (i.e., eight rats per group); therefore, the total number of study subjects was 48 rats. Study procedure Forty-eight Wistar albino rats (180–220 g) were used in the study. The rats were divided into six groups. The animals scheduled for surgical procedures in each group had their abdominal hair removed by a clipper before the pre-operative measurements and abdominal incision. Because we investigated the limits of Integuseal, we did not use standard skin disinfection (e.g., povidone-iodine, isopropyl alcohol). In the eight rats in the first group, the anti-microbial skin sealant was applied to the abdomen one minute after abdominal hair removal and 5 min before the abdominal incision. No attempt was made to sterilize the region after the application of the skin
15 sealant; the region was assumed to be sterile. As in clinical practice, sterile conditions and disposable sterile gloves were provided for surgery. After incision, the abdomen was closed in accordance with standard procedures. All of the incisions were made by disposable lancets. In the eight rats in the second (control) group, the only pre-operative skin preparation was hair removal; 5 min after hair removal, the abdominal incision was made, and then closure was performed. In the eight rats in the third group, cage swabs were applied to the abdominal skin one minute after pre-operative hair removal and 1 min before the microbial skin sealant was applied. The abdominal incision was made 5 min after the microbial skin sealant was applied, after which closing was performed. In the eight rats in the fourth (control) group, cage swabs were applied one minute after hair removal; then, 5 min after application of the cage swabs, the abdominal incision was made, followed by closure. In the eight rats in the fifth group, methicillin-resistant Staphylococcus aureus (MRSA) was applied to the abdominal skin one minute after hair removal. One minute after application of the MRSA, microbial skin sealant was applied. Five minutes after application of the microbial skin sealant, the abdominal incision was made, followed by closure. To the eight rats in the sixth (control) and last group, MRSA culture was applied to the abdominal skin 1 min after hair removal. Five minutes after application of the MRSA, the abdominal incision was made, followed by closure. Preparation of the cage swabs The combination of urine, sawdust, and stool of the animals housed in cages was mixed in tap water. One hour later, a liquid suspension was obtained by filtering the solid particles. The composition of the liquid suspension was analyzed by microbiologic techniques. Coagulase-negative Staphylococcus (CoNS) and gram-positive bacillus (GPB) bacteria were detected. All materials were manipulated with sterile swabs. Preparation of the MRSA inoculum The MRSA inoculum was prepared by our hospital’s microbiology department. Statistical Analysis Descriptive statistics, together with the observed number and percentage of the median for the number of bacteria, were shown as (min-max) CFU/g. The Mann-Whitney U test was used to determine the impact of skin sealant on the median number of bacteria in the experimental groups. Statistical analysis and calculations were performed with SPSS for Windows Ver. 15.0 (SPSS Inc., Chicago, IL). Statistical significance was accepted at the level of p £ 0.05. Results At the beginning of the study, eight rats had been assigned to each trial group. However, after the 7-d follow-up period, one rat in the skin sealant group (first group) and two rats in the control group (second group) expired; therefore, the study was completed with a total of 45 rats instead of the planned 48 rats. The skin sealant is known to remain on human skin a maximum of 5–7 d. Because there has been no previous animal experimental work on this subject, we deemed it sufficient in
n
%
n
%
Total
Skin sealant Control CS + skin sealant CS MRSA + skin sealant MRSA
5 6 0 5 8 8 32
71.4 100.0 0 62.5 100.0 100.0 71.1
2 0 8 3 0 0 13
28.6 0 100.0 37.5 0 0 28.9
7 6 8 8 8 8 45
CS = cage swabs; MRSA = methicillin-resistant Staphylococcus aureus.
N/A N/A N/A N/A 465.90 (80.15– 1014.00) 4,317.09 ( 6.18–7,875.00) 0/7 0/6 0/8 0/8 8/8 8/8 16/45 N/A N/A N/A N/A N/A 2,629.20 (758.40–4,500.00) 0/ 7 0/ 6 0/ 8 0/ 8 0/ 8 2/ 8 2/45 (50.40– 50.40) ( 9.35–1,832.00) (20.25– 38.60) (27.15–3,780.00) (96.18– 138.75) N/A 50.40 11.44 29.43* 359.10* 117.47 1/ 7 3/ 6 2/ 8 6/ 8 2/ 8 0/ 8 14/45 (8.96–672.00) (1.87–707.00) (2.12– 27.36) (5.46–132.80) N/A N/A 29.55 29.75 8.05 40.20
+/ n Median (min–max) +/ n
Median (min–max)
+/ n
PA GPB
*The difference between the median GPB counts of the CS and CS + skin sealant groups is statistically significant. CoNS = coagulase-negative staphylococci; CS = cage swabs; GPB = gram-positive bacillus; PA = Pseudomonas aeruginosa; MRSA = methicillin-resistant Staphylococcus aureus; N/A = not available.
1 2 3 4 5 6 Total
Group Type
7/ 7 6/ 6 8/ 8 4/ 8 0/ 8 0/ 8 25/45
Group #
Negative
Skin sealant Control CS + Skin sealant CS (control) MRSA + Skin sealant MRSA (control) Total
Positive
Median (min–max)
Bacterial Proliferation
+/ n
Table 1. The Results of the Trial Groups of Bacteria Culture
Group
Surgical site infection is a serious potential complication of surgery that, with its high association with morbidity and mortality, leads to prolonged hospitalization, repeated surgical procedures, and increased healthcare cost [10–13].
CoNS
Discussion
Table 2. Bacteria Observed in Tissue Samples of Trial Groups (Shown as Values* 10 - 3 CFU/g)
the present study to obtain samples through the seventh day, as in human beings. Considering that it was not possible to create sterile conditions for 7 d and assuming that all the animals were kept under standard conditions, we believed it was not necessary to obtain an extra sample beyond the seventh day. After the 7-d follow-up period, the rats were sacrificed. Using standard microbiologic techniques, equal amounts of culture samples were taken from the abdominal region of each rat, and placed in culture medium. After allowing sufficient time for the growth of bacteria, the bacterial counts in each group were analyzed. Bacterial growth was observed in five (71.4%) of the seven rats in the skin sealant group (first group) and in all six rats in the control group (second group). Table 1 shows the amount of bacteria observed in each experimental group. Table 2 shows the bacterial growth in the tissue samples from the study groups. Coagulase-negative staphylococci were found in all control samples, and in the skin sealant, cage swab (CS), and CS + skin sealant groups, but CoNS was not detected any of the samples of the MRSA and MRSA + skin sealant groups. Skin sealant growth was observed in one-half the samples of the CS group, but the other half of the samples in the CS group had no CoNS growth. No statistically significant differences were found in the median number of bacteria between the groups that did or did not receive skin sealant, with the exception of the median number of GPB between the CS and CS + skin sealant groups (p < 0.05). The median GPB count in the CS group was 359 100 cfu/g, while the CS + skin sealant group had a median GPB count of 29,430 CFU/g. This difference in the median GPB count between the CS and CS + skin sealant groups was statistically different (Z = 2.356; p = 0.028). Application of skin sealant prevented growth of GPB transmitted by cage swabs, yielding statistically significant and, therefore, successful results. Although statistically significant differences between the skin sealant group and its control groups were not found with respect to GPB count, the observed GPB sample rate decreased from 3/6 to 1/7. Skin sealant is therefore also effective against GPB, but not against GPB and MRSA together.
Median (min–max)
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MRSA
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MICROBIAL SKIN SEALANT ON SSI Thus, in our trial, we used a cyanoacrylate-based microbial sealant to determine its additional effect on prevention of wound contamination during surgery. Our study results showed that the rats treated with microbial sealant prior to skin incision had a lower rate of wound contamination that lasted for the duration of the 7-d follow-up period. The surgical incisions of the rats in the microbial sealant groups remained more sterile than those of the control groups. No statistically significant differences were found in the median number of bacteria between the groups and controls with respect to the different kinds of bacteria, with the exception of a statistically significant difference in the median number of GPB bacteria between the CS and CS + skin sealant groups (p < 0.05). The median GPB count was statistically different between the CS and CS + skin sealant groups (Z = 2.356; p = 0.028). We nevertheless determined that skin sealant was effective in all the other groups against the growth of GPB bacteria, although not against GPB and MRSA together. Our study showed that skin sealant was not as effective in preventing CoNS or MRSA bacterial contamination as it was in preventing GPB contamination. Our study has some limitations. First, we compared only superficial incisional SSIs within a 7-d follow-up period; it is possible that a longer follow-up period may have yielded different results. Second, the difficulties of keeping a wound sterile in animals are substantial, compared with patients. Third, because our study was an animal trial, all of the rats had similar risk factors. Another limitation is that we did not perform skin disinfection procedures before skin sealant application. Further studies to undertake more detailed characterization and risk factors of patients, longer follow-up duration, and sampling from incision sites before, during, and after surgery, with and without skin sealant, are needed to confirm the impact of this innovative pre-operative skin care strategy on SSI rates in clinical practice. A randomized clinical study to determine the efficacy of microbial skin sealant was conducted by Towfigh et al. [14]. Patients who underwent open, clean inguinal hernia repair and received microbial skin sealant after 10% povidone-iodine followed by iodine skin preparation had a significantly lower rate of surgical site contamination than patients treated with povidone-iodine alone (53.0 % vs. 68.7%; p = 0.04) (14). There have been a few studies that reported significant beneficial effects of microbial skin sealant on reducing the incidence of SSI. Dohmen et al. [15] conducted a case-control experiment demonstrating that the use of a microbial skin sealant prior to surgery could reduce the rate of SSI among patients undergoing cardiac surgery. In conclusion, the present study showed that the use of a microbial skin sealant prior to surgery could reduce the rate of SSI by its effect of reducing the migration of some specific bacterial agents. There were no cases of skin sensitivity or other reaction following application of the microbial sealant. We believe that skin sealant may be a new and innovative preoperative skin care strategy to minimize bacterial contamination of surgical incisions. However, further data are needed to validate its use in clinical practice. Acknowledgments The authors thank Marilyn Carlson for her editorial assistance.
17 Author Disclosure Statement No competing financial interests exist. References 1. Mangram AJ, Horan TC, Pearson ML, et al. Guidelines for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee. Infect Control Hosp Epidemiol 1999;20:250–278. 2. Edwards PS, Lipp A, Holmes A. Preoperative skin antiseptics for preventing surgical wound infections after clean surgery. Cochrane Database Syst Rev 2004;CD003949 3. Homer-Vanniasinkam S. Surgical site and vascular infections: Treatment and prophylaxis. Int J Infect Dis 2007;11:S17–S22. 4. Bratzler DW, Hunt DR. The surgical infection prevention and surgical care improvement projects: National initiatives to improve outcomes for patients having surgery. Clin Infect Dis 2006;43:322–330. 5. Dimick JB, Pronovost PJ, Cowan JA, Lipsett PA. Complications and costs after high-risk surgery: Where should we focus quality improvement initiatives? J Am Coll Surg 2003;196:671–678. 6. Dohmen PM, Weymann A, Holinski S, et al. Use of an antimicrobial skin sealant reduces surgical site infection in patients undergoing routine cardiac surgery. Surg Infect (Larchmt) 2011;12:475–481. 7. Von Eckardstein AS, Lim CH, Dohmen PM, et al. A randomized trial of skin sealant to reduce the risk of incision contamination in cardiac surgery. Ann Thorac Surg 2011;92: 632–637. 8. Dohmen PM. Antibiotic resistance in common pathogens reinforces the need to minimise surgical site infections. J Hosp Infect 2008;70:15–20. 9. Wilson SE. Microbial sealing: A new approach to reducing contamination. J Hosp Infect 2008;70:11–14. 10. Salehi Omran A, Karimi A, Ahmadi SH, et al. Superficial and deep sternal wound infection after more than 9000 coronary artery bypass graft (CABG): Incidence, risk factors and mortality. BMC Infect Dis 2007;7:112. 11. Fry DE. The economic costs of surgical site infection. Surg Infect (Larchmt) 2002;3:S37–S43. 12. Dohmen PM, Gabbieri D, Weymann A, et al. A retrospective non-randomized study on the impact of INTEGUSEAL, a preoperative microbial skin sealant, on the rate of surgical site infections after cardiac surgery. Int J Infect Dis 2011;15: 395–400. 13. Ga˚rdlund B. Postoperative surgical site infections in cardiac surgey–an overwiev of preventive measures. APMIS 2007;115: 989–995. 14. Towfigh S, Cheadle WG, Lowry SF, et al. Significant reduction in incidence of wound contamination by skin flora through use of microbial sealant. Arch Surg 2008;143:885–891. 15. Dohmen PM, Gabbieri D, Weymann A, et al. Reduction in surgical site infection in patients treated with microbial sealant prior to coronary artery bypass graft surgery: A casecontrol study. J Hosp Infect 2009;72:119–126.
Address correspondence to: Dr. Mehmet Saydam Department of General Surgery Ankara Mevki Military Hospital Ankara, Turkey 06110 E-mail: [email protected]
