Epidemiology and prevention of surgical site infection in Japan.

Healthcare-associated infection control practices in Japan were not commonly acknowledged until mid-1980s, when an academic society focusing on infection control was founded and large academic hospitals began to establish infection control departments. In the late 1990s, the society established a nationwide surveillance system mainly focusing on surgical site infection (SSI). Coincidentally, the guideline for the prevention of SSI published by the US Centers for Disease Control and Prevention (CDC) was revised in 1999. It was translated into Japanese, and has been widely referenced in Japanese clinical practices. Since then, both epidemiological research and preventive practices in Japan have been developed. Overall SSI incidence was about 10% in the early 2000s, but fell to 7% by 2007, with a further reduction to 5% in 2020. A large SSI database cohort created through surveillance enabled us to conduct research regarding risk factors for SSI following various types of surgery. In mid-2010s, the revision of CDC's SSI prevention guideline and the new one by the World Health Organization were published. Novel evidence-based SSI prevention practices such as normal body temperature and antiseptic-impregnated sutures are recommended, and have been timely introduced into Japanese surgical practice. However, many of the practices and devices shown to be effective in preventing SSI are not approved for reimbursement by public healthcare insurance in Japan, which has so far prevented those measures from being widely used in Japanese healthcare.

Effect of participation in a surgical site infection surveillance programme on hospital performance in Japan: a retrospective study.

BACKGROUND: The effect of hospital participation in the Japan Nosocomial Infection Surveillance (JANIS) programme on surgical site infection (SSI) prevention is unknown. AIM: To determine if participation in the JANIS programme improved hospital performance in SSI prevention. METHODS: This retrospective before-after study analysed Japanese acute care hospitals that joined the SSI component of the JANIS programme in 2013 or 2014. The study participants comprised patients who had undergone surgeries targeted for SSI surveillance at JANIS hospitals between 2012 and 2017. Exposure was defined as the receipt of an annual feedback report 1 year after participation in the JANIS programme. The changes in standardized infection ratio (SIR) from 1 year before to 3 years after exposure were calculated for 12 operative procedures: appendectomy, liver resection, cardiac surgery, cholecystectomy, colon surgery, caesarean section, spinal fusion, open reduction of long bone fracture, distal gastrectomy, total gastrectomy, rectal surgery, and small bowel surgery. Logistic regression models were used to analyse the association of each post-exposure year with the occurrence of SSI. FINDINGS: In total, 157,343 surgeries at 319 hospitals were analysed. SIR values declined after participation in the JANIS programme for procedures such as liver resection and cardiac surgery. Participation in the JANIS programme was significantly associated with reduced SIR for several procedures, especially after 3 years. The odds ratios in the third post-exposure year (reference: pre-exposure year) were 0.86 [95% confidence interval (CI) 0.79-0.84] for colon surgery, 0.72 (95% CI 0.56-0.92) for distal gastrectomy, and 0.77 (95% CI 0.59-0.99) for total gastrectomy. CONCLUSION: Participation in the JANIS programme was associated with improved SSI prevention performance in several procedures in Japanese hospitals after 3 years.

Improving surgical site infection prevention in Asia-Pacific through appropriate surveillance programs: Challenges and recommendation.

BACKGROUND: Surgical site infections (SSIs) represent a substantial clinical and economic burden on patients and the healthcare system. The prevention of SSIs entails surveillance activities which lead to effective mitigation strategies, which are lacking across Asia Pacific (APAC). This manuscript aims to document gaps and challenges across APAC that affect the undertaking of a successful SSI surveillance activities and to provide recommendations on overcoming such challenges. METHODS: A targeted literature review with relevance to APAC identified a series of salient points pertaining to SSI prevention guidelines, implementation, surveillance and outcomes, which was discussed in July 2019 at the APAC Surgical Site Infection Prevention Symposium. An expert panel, comprising eight multidisciplinary experts from APAC and the USA, subsequently amalgamated the key discussion points from the Symposium and their clinical experiences in developing this article. RESULTS: The barriers to implementing a successful and effective APAC SSI surveillance program were identified as: (a) lack of standardized definitions, reporting methodology and accountability, (b) lack of fiscal resources, (c) reporting variability and under-reporting, and (d) lack of safety culture. Implementing an effective surveillance program in APAC will require countries to develop a well-designed and robust surveillance plan and ensure adequate training for staffs involved. CONCLUSION: To improve SSI prevention in the region, it is imperative to encourage implementation of national programs with standardized methodologies and accountabilities. An ongoing APAC information exchange, including data and methodologies, will enable continuous learning within the APAC region.

Expert commentary on the challenges and opportunities for surgical site infection prevention through implementation of evidence-based guidelines in the Asia-Pacific Region.

INTRODUCTION: Surgical site infections (SSIs) are a significant source of morbidity and mortality in the Asia-Pacific region (APAC), adversely impacting patient quality of life, fiscal productivity and placing a major economic burden on the country's healthcare system. This commentary reports the findings of a two-day meeting that was held in Singapore on July 30-31, 2019, where a series of consensus recommendations were developed by an expert panel composed of infection control, surgical and quality experts from APAC nations in an effort to develop an evidence-based pathway to improving surgical patient outcomes in APAC. METHODS: The expert panel conducted a literature review targeting four sentinel areas within the APAC region: national and societal guidelines, implementation strategies, postoperative surveillance and clinical outcomes. The panel formulated a series of key questions regarding APAC-specific challenges and opportunities for SSI prevention. RESULTS: The expert panel identified several challenges for mitigating SSIs in APAC; (a) constraints on human resources, (b) lack of adequate policies and procedures, (c) lack of a strong safety culture, (d) limitation in funding resources, (e) environmental and geographic challenges, (f) cultural diversity, (g) poor patient awareness and (h) limitation in self-responsibility. Corrective strategies for guideline implementation in APAC were proposed that included: (a) institutional ownership of infection prevention strategies, (b) perform baseline assessments, (c) review evidence-based practices within the local context, (d) develop a plan for guideline implementation, (e) assess outcome and stakeholder feedback, and (f) ensure long-term sustainability. CONCLUSIONS: Reducing the risk of SSIs in APAC region will require: (a) ongoing consultation and collaboration among stakeholders with a high level of clinical staff engagement and (b) a strong institutional and national commitment to alleviate the burden of SSIs by embracing a safety culture and accountability.

Epidemiology and risk factors associated with surgical site infection following surgery on thoracic aorta.

Surgical site infection (SSI) following cardiovascular surgery has been well documented, possibly owing to its highly invasive nature, but SSI following surgery on the thoracic aorta has not. This study aimed to describe the epidemiology and assess risk factors associated with the latter in Japan using a national database for SSI. Data on surgery on thoracic aorta performed between 2012 and 2014 were extracted from the Japan Nosocomial Infections Surveillance (JANIS) database. Risk factors were assessed initially by univariate analysis, and then entered into a logistic regression model for final evaluation. The cumulative incidence of SSI was 4.1% (146/3538) and staphylococci were the most frequent pathogens isolated. Factors such as the duration of operation, emergency surgery and male gender were significantly associated with SSI. These findings differ from previous studies on open heart and coronary artery bypass surgery, in which the American Society of Anesthesiologists (ASA) score was significantly associated with SSI, but gender was not. This study suggests that risk stratification in the JANIS system might be improved by incorporating additionally identified factors for risk adjustment, when comparing the incidence of SSI between hospitals.

Differences in risk factors associated with surgical site infections following two types of cardiac surgery in Japanese patients.

BACKGROUND: Differences in the risk factors for surgical site infection (SSI) following open heart surgery and coronary artery bypass graft surgery are not well described. AIM: To identify and compare risk factors for SSI following open heart surgery and coronary artery bypass graft surgery. METHODS: SSI surveillance data on open heart surgery (CARD) and coronary artery bypass graft surgery (CBGB) submitted to the Japan Nosocomial Infection Surveillance (JANIS) system between 2008 and 2010 were analysed. Factors associated with SSI were analysed using univariate modelling analysis followed by multi-variate logistic regression analysis. Non-binary variables were analysed initially to determine the most appropriate category. FINDINGS: The cumulative incidence rates of SSI for CARD and CBGB were 2.6% (151/5895) and 4.1% (160/3884), respectively. In both groups, the duration of the operation and a high American Society of Anesthesiologists' (ASA) score were significant in predicting SSI risk in the model. Wound class was independently associated with SSI in CARD but not in CBGB. Implants, multiple procedures and emergency operations predicted SSI in CARD, but none of these factors predicted SSI in CBGB. CONCLUSIONS: There was a remarkable difference in the prediction of risk for SSI between the two types of cardiac surgery. Risk stratification in CARD could be improved by incorporating variables currently available in the existing surveillance systems. Risk index stratification in CBGB could be enhanced by collecting additional variables, because only two of the current variables were found to be significant for the prediction of SSI.

Impact of surgical site infections after open and laparoscopic colon and rectal surgeries on postoperative resource consumption.

PURPOSE: To estimate the impact of surgical site infection (SSI) on postoperative resource consumption for colon and rectal open and laparoscopic surgeries after accounting for infection depth and patient characteristics, and to compare these estimates among institutions. METHODS: We collected administrative and SSI-related data from eight Japanese hospitals, and used generalized linear models to estimate excess postoperative length of stay (LOS) and charges attributable to SSI. Covariates included wound class, American Society of Anesthesiologists (ASA) score, operation time, emergency, colostomy, trauma, implant, and comorbidities. RESULTS: We examined 1,108 colon surgery (CS) and 477 rectal surgery (RS) patients. For open surgery, the postoperative LOS in non-SSI patients was 13.5 (CS) and 15.9 days (RS). Compared with non-SSI patients, the postoperative LOS increased by 4.5 (CS) and 2.8 days (RS) for superficial SSI, 6.8 (CS) and 8.5 days (RS) for deep SSI, and 7.8 and 9.5 days for space/organ SSI. For laparoscopic surgery, the postoperative LOS was 9.8 (CS) and 14.6 days (RS). SSI was significantly associated with increased postoperative LOS for superficial SSI [by 4.8 (CS) and 3.6 days (RS)], deep SSI [by 10.3 (CS) and 23.9 days (RS)], and space/organ SSI [by 8.9 days (RS)]. The postoperative LOS among hospitals was 3.8-10.4 days (CS) and 1.3-12.2 days (RS). Postoperative SSI-attributable charges ranged from $386 to $2,873, depending on organ, procedure, and infection depth. CONCLUSION: This study quantified the impact of SSIs on resource consumption and confirmed significant cost variations among hospitals. These variations could not be explained by patient characteristics or infection type.

A norovirus outbreak associated with environmental contamination at a hotel.

SUMMARYIn December 2006, an outbreak of gastroenteritis occurred involving 372 guests and 72 employees at a hotel after a guest vomited in corridors on the third (F3) and 25th (F25) floors. Norovirus with identical genotype was confirmed by real-time reverse transcription-polymerase chain reaction in faecal samples from guest cases and employees. Spread of the outbreak on F25 was compared with that on F3. The attack rate in the guests who visited F25 alone (15·0%, 106/708 guests) was significantly higher than in those who visited F3 alone (3·5%, 163/4710 guests) (relative risk 4·3, 95% confidence interval 3·4-5·5, P < 0·001). The outbreak on F3 ended within 2 days, while that on F25 extended over 7 days. The environmental ratios of F3 to F25 were 7·4 for volume, 6·9 for floor area and 7·6 for ventilation rate. This outbreak suggests that environmental differences can affect the propagation and persistence of a norovirus outbreak following environmental contamination.

The human homologue of the RNA polymerase II-associated factor 1 (hPaf1), localized on the 19q13 amplicon, is associated with tumorigenesis.

The 19q13 amplicon in pancreatic cancer cells contains a novel pancreatic differentiation 2 (PD2) gene (accession number AJ401156), which was identified by differential screening analysis. PD2 is the human homologue of the RNA polymerase II-associated factor 1 (hPaf1). In yeast, Paf1 is part of the transcription machinery, acting as a docking protein in between the complexes Rad6-Bre1, COMPASS-Dot1p, and the phosphorylated carboxyl terminal domain of the RNA polymerase II. As such, Paf1 is directly involved in transcription elongation via histone H2B ubiquitination and histone H3 methylation. The PD2 sequence is highly conserved from Drosophila to humans with up to 98% identity between rodent and human, suggesting the functional importance of PD2/hPaf1 to maintain cellular homeostasis. PD2 is a modular protein composed of RNA recognition motif, DEAD-boxes, an aspartic/serine (DS)-domain, a regulator of the chromosome condensation domain and myc-type helix-loop-helix domains. Our results further showed that PD2 is a nuclear 80 kDa protein, which interacts with RNA polymerase II. In addition, we have demonstrated that the overexpression of PD2 in the NIH 3T3 cells result in enhanced growth rates in vitro and tumor formation in vivo. Altogether, this paper presents strong evidence that the overexpression of PD2/hPaf1 is involved in cancer development.

Influence of organ site and tumor cell type on MUC1-specific tumor immunity.

We investigated the influence of organ-specific parameters on tolerance and immunity to human MUC1. C57Bl/6 mice (wild-type) and C57Bl/6 transgenic for MUC1 (MUC1.Tg) were challenged in the pancreas with Panc02-MUC1, a C57Bl/6-syngeneic pancreatic cancer cell line expressing human MUC1. Wild-type mice produced immune responses to MUC1 when presented on tumor cells growing in the pancreas; however, the responses to tumors in the pancreas were less effective than responses produced by tumor challenge at the s.c. site. Tumor immunity specific for MUC1 was produced in wild-type mice by two different procedures: (i) s.c. immunization of wild-type mice with a low dose of Panc02-MUC1 or (ii) adoptive transfer of spleen and lymph node cells harvested from wild-type mice previously immunized s.c. with Panc02-MUC1. This demonstrates that immune responses to MUC1 presented at the s.c. site can be detected and adoptively transferred. MUC1.Tg mice were immunologically tolerant to MUC1; however, some immunological protection against orthotopic challenge with Panc02-MUC1 was conferred by adoptive transfer of CD4+ and CD8+ T cells from wild-type mice. These results show that it is more difficult to produce immune responses to tumors growing at the pancreatic site than the s.c. site. Panc02-MUC1 cells growing in the pancreas were accessible to the immune system, and immune responses evoked by s.c. presentation of this molecule in wild-type mice were effective in rejecting tumor cells in the pancreas of both wild-type and MUC1.Tg mice. No effective anti-tumor immune responses against MUC1 were produced in MUC1.Tg mice.

Organ-specific pancreatic tumor growth properties and tumor immunity.

We established a model of orthotopic injection of a syngeneic pancreatic tumor cell line in C57BL/6 mice and evaluated the effects of organ site on induction of immunity to a tumor-specific antigen, MUC1. Mice were challenged with a syngeneic pancreatic adenocarcinoma cell line that expressed MUC1 (Panc02-MUC1) by orthotopic injection into the pancreas, or by subcutaneous injection. Tumor cells injected into the pancreas grew much faster than those injected subcutaneously. Mice challenged subcutaneously with Panc02-MUC1 rejected tumors or developed slowly growing tumors that were negative for MUC1 expression. In contrast, mice challenged orthotopically into the pancreas developed progressive tumors that were positive for MUC1 expression. Sera from mice that rejected PancO2-MUC1 (tumor-immune mice) showed no detectable IgG1 and IgM titers against the MUC1 tandem-repeat peptide, whereas mice with progressive tumor growth had significant titers of IgG1 and IgM specific for MUC1. This suggests that the humoral immune response was ineffective in mediating tumor rejection. The results show that the growth properties and immunological rejection of pancreatic tumors is affected by the organ site at which the tumor grows.

CD4+ lymphocytes provide MUC1-specific tumor immunity in vivo that is undetectable in vitro and is absent in MUC1 transgenic mice.

A C57BL/6 mouse transgenic for human MUC1 (MUC1.Tg) was developed to evaluate MUC1-specific tumor immunity in an animal that expresses MUC1 as a normal self protein. Previous studies showed that MUC1.Tg mice, challenged with syngeneic tumors expressing MUC1 (B16.MUC1), developed progressively growing MUC1-positive tumors, whereas wild-type C57BL/6 (wt) mice developed MUC1-negative tumors at a significantly slower rate. The results of a limiting dilution CTL frequency assay were not informative, in that similar numbers of MUC1-specific CTL precursors (CTL) were detected in MUC1.Tg and wt mice. Tumor immunity in vivo was characterized by an adoptive transfer method to evaluate the degree of MUC1 or non-MUC1 tumor immunity in wt or MUC1.Tg mice. The results revealed that wt mice developed protective tumor immunity mediated by MUC1-specific CD4+ lymphocytes, while MUC1.Tg mice were functionally tolerant to MUC1 in vivo. The potential of adoptive immunotherapy to provide immunity to tumors expressing MUC1 and to produce undesirable autoimmunity in recipient MUC1.Tg mice expressing MUC1 as a self Ag was evaluated. Adoptive transfer of immune cells from wt mice primed in vivo with B16.MUC1 tumor cells into MUC1.Tg recipients resulted in significant increases in the survival of MUC1.Tg recipients compared with unmanipulated control MUC .Tg mice challenged with B16.MUC1 tumor cells. This response was specific for MUC1 since control tumors developed at equivalent rates in recipient or control MUC1.Tg mice. No gross or histologic evidence of autoimmunity was observed in recipient MUC1.Tg mice, indicating that tumor immune responses mediated by MUC1-specific CD4+ lymphocytes spare nontransformed epithelia-expressing MUC1.

Histologic and biologic patterns of microscopic pancreatic ductal adenocarcinomas detected incidentally at autopsy.

BACKGROUND: The major clinical problems with pancreatic carcinoma are its silent course and late, fatal clinical manifestation. The results of treatments of small pancreatic carcinomas (<2 cm in greatest dimension) have led to the assumption that the detection of these cancers at earlier stages would lead to better survival and possible cure. Currently, there is no information about the histologic and biologic patterns of early stage pancreatic carcinoma, and the available data on incidentally detected tumors are fragmentary. The authors observed two incidental microscopic pancreatic ductal adenocarcinomas in female patients who died of advanced gastric carcinoma (Case 1) and renal carcinoma (Case 2). METHODS: The pancreatic lesions were examined histologically in serial sections and immunocytochemically for islet cells. Microdissection was performed so that the lesions could be examined for c-Ki-ras mutation. RESULTS: In Case 1, the pancreatic lesion was composed of cystic and solid components. The cystic component consisted of four small cysts compatible with a mucinous cystic tumor and showed no invasion. The solid component was a well-differentiated adenocarcinoma that occupied a 4 x 2 mm area. In Case 2, the pancreatic lesion contained two small, separate cysts, one of which was surrounded by two apparently separate, invasive adenocarcinomas 2.6 x 0.7 mm and 1.2 x 0.5 mm in greatest dimension. There was invasion of pancreatic islets and perineural spaces in both cases; and in Case 2, there was invasion of peripancreatic fatty tissue. In both cases, the epithelia of the cystic components and tumors showed mutation of the c-Ki-ras oncogene at codon 12, with GGT-to-GAT transition. CONCLUSIONS. Pancreatic carcinoma seems to occur under occult circumstances and maintain a silent course. Even in its early developmental stage, the cancer is invasive, primarily affects islets and nerves, and exhibits mutation of the c-Ki-ras oncogene. These findings call for urgency in the development of preventive modalities.

A small glucagonoma of the pancreas with evident ductular and tubular structures.

A 54-year-old woman was admitted to our department for assessment of a tumor of the pancreas found incidentally on abdominal ultrasonography. Examination revealed a hypovascular 1-cm sized tumor in the body of the pancreas. Surgical examination revealed that the tumor was solitary and located in the pancreas body, with no invasion to the adjacent organs iof lymph node involvement. Distal pancreatectomy, preserving the spleen, was performed. Histologically, the tumor was a glucagonoma with evident ductular and tubular structures, suggesting that its site of origin was ductal epithelia.

A new method of duodenum-preserving subtotal resection of the head of the pancreas based on the surgical anatomy.

BACKGROUND/AIMS: Duodenum-preserving resection of the head of the pancreas has been performed for benign and, sometimes, malignant diseases of the pancreas. We propose a new procedure of duodenum-preserving subtotal pancreatectomy of the pancreas according to the precise anatomy of the pancreatoduodenal region, especially of the pancreaticoduodenal arteries which provide blood to the duodenum. MATERIAL AND METHODS: After a complete Kocher's maneuver is performed, the pancreas is cut above the portal vein and removed from the third portion of the duodenum, followed by the removal of the posterior surface of the pancreas head from a connective tissue membrane. The main pancreatic duct is identified at its junction with the terminal portion of the bile duct from the posterior surface of the head of the pancreas and is cut at the junction. The pancreas is cut in the line of the ASPD. This line is almost the same as the left side of the common bile duct. The ASPD and the common bile duct should be preserved in this procedure. RESULTS: The reason for leaving part of the pancreas between the duodenum and the anterior superior pancreaticoduodenal artery and the common bile duct is that the artery toward the papilla of Vater runs along the right side of the common bile duct and would be difficult to be preserved with the removal of this part of the pancreas. The most important technique of this procedure is in keeping the connective tissue membrane of the posterior surface of the pancreas intact so as to preserve pancreaticoduodenal arteries and veins, because all the pancreaticoduodenal arteries and veins are situated on this membrane. Complete Kocher's maneuver should cause no problem in this procedure. CONCLUSIONS: Benign lesions as well as low-grade malignancy of the head of the pancreas may possibly be the indication of this procedure.