BACKGROUND:Dexamethasone and hindlimb suspension are commonly used methods for modeling sarcopenia in animal experiments due to their short modeling time,ease of operation,and low cost.OBJECTIVE:To compare the differences in muscle mass,strength and functional phenotypes and molecular mechanisms between two mouse sarcopenia models induced by dexamethasone and hindlimb suspension.METHODS:Thirty male C57BL/6 mice were randomly divided into three groups(n=10 per group).The normal control group received no intervention.The dexamethasone group received daily intraperitoneal injections of 1 mg/kg/d dexamethasone sodium phosphate solution for 6 continuous days to establish sarcopenia models in mice,while mice in the hindlimb suspension group were suspended by tail harness for 16 hours,once per day,to establish sarcopenia models.Within 6 weeks after modeling,changes in body mass were monitored.After 6 weeks of modeling,mice were tested for limb grip strength,mobility(swimming test),skeletal muscle wet mass,and skeletal muscle pathological morphology.Expressions of skeletal muscle protein synthesis and catabolism indexes as well as the AMPK/FoXO3α signaling pathway were detected by RT-PCR and western blot.RESULTS AND CONCLUSION:(1)Two weeks after modeling,both dexamethasone and hindlimb suspension groups showed a significant decrease in body mass compared with the normal control group(P<0.001).After 6 weeks of modeling,grip strength of mice in both dexamethasone and hindlimb suspension groups was lower than that in the normal control group(P<0.001).The wet mass of gastrocnemius and extensor digitorum longus muscles and the cross-sectional area of gastrocnemius and soleus muscles in the dexamethasone group were lower than those in the normal control group(P<0.05).Compared with the hindlimb suspension group,the cross-sectional area of gastrocnemius muscle was significantly smaller in the dexamethasone group(P<0.05),while the cross-sectional area of soleus muscle was larger in the dexamethasone group(P<0.05).Mice in the dexamethasone group had reduced mobility when compared with those in the normal control group and the hindlimb suspension group(P<0.05).(3)Compared with the normal control group,PI3K,mTOR,AMPK,and PGC-1α mRNA expression and P-AMPK/AMPK protein were decreased in the two modeling groups(P<0.05),and FoXO3α mRNA expression and PGC-1α and FoXO3 protein expression were elevated(P<0.05);in the dexamethasone group,Akt1 mRNA expression was decreased(P<0.05),while Atrogin-1 and MuRF-1 mRNA expression was elevated(P<0.05);in the hindlimb suspension group,Akt1 mRNA expression was elevated(P<0.05).(4)Compared with the dexamethasone group,mTOR,Akt1,and FoXO3α mRNA expression was elevated in the hindlimb suspension group(P<0.05),while Atrogin-1 and MuRF-1 mRNA expression was decreased(P<0.05).To conclude,both modeling methods could decrease the levels of mitochondrial energy metabolism in skeletal muscle,with the dexamethasone group mediating atrophy of skeletal muscle through the dual action of ubiquitin proteasome and energy metabolism pathways,and the hindlimb suspension group inducing atrophy of skeletal muscle by mediating the energy metabolism pathway through the AMPK/FoXO3α signaling pathway,subsequently causing a reduction in mass,strength,and function of skeletal muscle.

BACKGROUND:Dexamethasone and hindlimb suspension are commonly used methods for modeling sarcopenia in animal experiments due to their short modeling time,ease of operation,and low cost.OBJECTIVE:To compare the differences in muscle mass,strength and functional phenotypes and molecular mechanisms between two mouse sarcopenia models induced by dexamethasone and hindlimb suspension.METHODS:Thirty male C57BL/6 mice were randomly divided into three groups(n=10 per group).The normal control group received no intervention.The dexamethasone group received daily intraperitoneal injections of 1 mg/kg/d dexamethasone sodium phosphate solution for 6 continuous days to establish sarcopenia models in mice,while mice in the hindlimb suspension group were suspended by tail harness for 16 hours,once per day,to establish sarcopenia models.Within 6 weeks after modeling,changes in body mass were monitored.After 6 weeks of modeling,mice were tested for limb grip strength,mobility(swimming test),skeletal muscle wet mass,and skeletal muscle pathological morphology.Expressions of skeletal muscle protein synthesis and catabolism indexes as well as the AMPK/FoXO3α signaling pathway were detected by RT-PCR and western blot.RESULTS AND CONCLUSION:(1)Two weeks after modeling,both dexamethasone and hindlimb suspension groups showed a significant decrease in body mass compared with the normal control group(P<0.001).After 6 weeks of modeling,grip strength of mice in both dexamethasone and hindlimb suspension groups was lower than that in the normal control group(P<0.001).The wet mass of gastrocnemius and extensor digitorum longus muscles and the cross-sectional area of gastrocnemius and soleus muscles in the dexamethasone group were lower than those in the normal control group(P<0.05).Compared with the hindlimb suspension group,the cross-sectional area of gastrocnemius muscle was significantly smaller in the dexamethasone group(P<0.05),while the cross-sectional area of soleus muscle was larger in the dexamethasone group(P<0.05).Mice in the dexamethasone group had reduced mobility when compared with those in the normal control group and the hindlimb suspension group(P<0.05).(3)Compared with the normal control group,PI3K,mTOR,AMPK,and PGC-1α mRNA expression and P-AMPK/AMPK protein were decreased in the two modeling groups(P<0.05),and FoXO3α mRNA expression and PGC-1α and FoXO3 protein expression were elevated(P<0.05);in the dexamethasone group,Akt1 mRNA expression was decreased(P<0.05),while Atrogin-1 and MuRF-1 mRNA expression was elevated(P<0.05);in the hindlimb suspension group,Akt1 mRNA expression was elevated(P<0.05).(4)Compared with the dexamethasone group,mTOR,Akt1,and FoXO3α mRNA expression was elevated in the hindlimb suspension group(P<0.05),while Atrogin-1 and MuRF-1 mRNA expression was decreased(P<0.05).To conclude,both modeling methods could decrease the levels of mitochondrial energy metabolism in skeletal muscle,with the dexamethasone group mediating atrophy of skeletal muscle through the dual action of ubiquitin proteasome and energy metabolism pathways,and the hindlimb suspension group inducing atrophy of skeletal muscle by mediating the energy metabolism pathway through the AMPK/FoXO3α signaling pathway,subsequently causing a reduction in mass,strength,and function of skeletal muscle.

Background::Previous studies have reported associations of specific maternal and paternal lifestyle factors with offspring’s cognitive development during early childhood. This study aimed to investigate the prospective associations between overall parental lifestyle and offspring’s cognitive performance during adolescence and young adulthood in China.Methods::We included 2531 adolescents aged 10-15 years at baseline in 2010 from the China Family Panel Studies. A healthy parental lifestyle score (ranged 0-5) was constructed based on the following five modifiable lifestyle factors: Smoking, drinking, exercise, sleep, and diet. Generalized estimating equation models were used to examine the association between baseline parental healthy lifestyle scores and offspring’s fluid and crystallized intelligence in subsequent years (2012, 2014, 2016, and 2018).Results::Offspring in the top tertile of parental healthy lifestyle scores performed better in overall fluid intelligence (multivariable-adjusted β = 0.53, 95% confidence interval [CI]: 0.29-0.77) and overall crystallized intelligence (multivariable-adjusted β = 0.35, 95% CI: 0.16-0.54) than those in the bottom tertile of parental healthy lifestyle scores. The results were similar after further adjustment for the offspring’s healthy lifestyle scores and persisted across the subgroups of parental socioeconomic status. Additionally, maternal and paternal healthy lifestyle scores were independently associated with better offspring’s cognitive performance, with significant contribution observed for paternal never-smoking, weekly exercise, and diversified diet. When both parents and offspring adhered to a healthier lifestyle, we observed the highest level of the offspring’s overall crystallized intelligence. Conclusions::Our study indicates that parental adherence to a healthier lifestyle is associated with significantly better offspring’s cognitive performance during adolescence and early adulthood, regardless of socioeconomic status. These findings highlight the potential cognitive benefits of promoting healthy lifestyles among parents of adolescents.

Objective:We investigated the incidence of surgical site infection (SSI) following emergency abdominal surgery (EAS) in China and further explored its risk factors, providing a reference for preventing and controlling SSI after EAS.Methods:This was an observational study. Data of patients who had undergone EAS and been enrolled in the Chinese SSI Surveillance Program during 2018–2021were retrospectively analyzed. All included patients had been followed up for 30 days after surgery. The analyzed data consisted of relevant patient characteristics and perioperative clinical data, including preoperative hemoglobin, albumin, and blood glucose concentrations, American Society of Anesthesiologists (ASA) score, grade of surgical incision, intestinal preparation, skin preparation, location of surgical site, approach, and duration. The primary outcome was the incidence of SSI occurring within 30 days following EAS. SSI was defined as both superficial and deep incisional infections and organ/space infections, diagnoses being supported by results of microbiological culture of secretions and pus. Secondary outcomes included 30-day postoperative mortality rates, length of stay in the intensive care unit (ICU), duration of postoperative hospitalization, and associated costs. The patients were classified into two groups, SSI and non-SSI, based on whether an infection had been diagnosed. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with SSI following EAS.Results:The study cohort comprised 5491 patients who had undergone EAS, comprising 3169 male and 2322 female patients. SSIs were diagnosed in 168 (3.1%) patients after EAS (SSI group); thus, the non-SSI group consisted of 5323 patients. The SSIs comprised superficial incision infections in 69 (41.1%), deep incision infections in 51 (30.4%), and organ or space infections in 48 (28.6%). Cultures of secretions and pus were positive in 115 (68.5%) cases. The most frequently detected organism was Escherichia coli (47/115; 40.9%). There were no significant differences in sex or body mass index between the SSI and non-SSI groups (both P>0.05). However, the proportion of individuals aged 60 years or older was significantly greater in the SSI than in the non-SSI group (49.4% [83/168] vs. 27.5% [1464/5323), χ 2=38.604, P<0.001). Compared with the non-SSI group, the SSI group had greater proportions of patients with diabetes (11.9% [20/168] vs. 4.8% [258/5323], χ 2=16.878, P<0.001), hypertension (25.6% [43/168] vs. 12.2% [649/5323], χ 2=26.562, P<0.001); hemoglobin <110 g/L (27.4% [46/168] vs. 13.1% [697/5323], χ 2=28.411, P<0.001), and albuminemia <30 g/L (24.4% [41/168] vs. 5.9% [316/5323], χ 2=91.352, P<0.001), and a reduced rate of preoperative skin preparation (66.7% [112/168] vs. 75.9% [4039/5323], χ 2=7.491, P=0.006). Furthermore, fewer patients in the SSI group had preoperative ASA scores of between one and two (56.0% [94/168] vs. 88.7% [4724/5323], χ 2=162.869, P<0.001) in the non-SSI group. The incidences of contaminated and infected incisions were greater in the SSI group (63.1% [106/168] vs. 38.6% [2056/5323], χ 2=40.854, P<0.001). There was a significant difference in surgical site distribution between the SSI and non-SSI groups (small intestine 29.8% [50/168] vs. 10.6% [565/5323], colorectal 26.2% [44/168] vs. 5.6% [298/5 323], and appendix 24.4% [41/168] vs. 65.1% [3465/5323]) χ 2=167.897, P<0.001), respectively. There was a significantly lower proportion of laparoscope or robotic surgery in the non-SSI group (24.4 % [41/168] vs. 74.2% [3949/5323], χ 2=203.199, P<0.001); the percentage of operations of duration less than 2 hours was significantly lower in the SSI than non-SSI group (35.7% [60/168] vs. 77.4% [4119/5323], χ 2=155.487, P<0.001). As to clinical outcomes, there was a higher 30-day postoperative mortality rate (3.0%[5/168] vs. 0.2%[10/5323], χ 2=36.807, P<0.001) and higher postoperative ICU occupancy rate (41.7% [70/168] vs. 19.7% [1046/5323], χ 2=48.748, P<0.001) in the SSI group. The median length of stay in the ICU (0[2] vs. 0[0] days, U=328597.000, P<0.001), median total length of stay after surgery (16[13] vs. 6[5] days, U=128146.000, P<0.001), and median hospitalization cost (ten thousand yuan, 4.7[4.4] vs. 1.7[1.8], U=175965.000, P<0.001) were all significantly greater in the SSI group. Multivariate logistic regression analysis revealed that the absence of skin preparation before surgery (OR=2.435,95%CI: 1.690–3.508, P<0.001), preoperative albuminemia <30 g/L (OR=1.680, 95%CI: 1.081–2.610, P=0.021), contaminated or infected incisions (OR=3.031, 95%CI: 2.151–4.271, P<0.001), and laparotomy (OR=3.436, 95% CI: 2.123–5.564, P<0.001) were independent risk factors of SSI. Operative duration less than 2 hours (OR=0.465, 95%CI: 0.312–0.695, P<0.001) and ASA score of 1–2 (OR=0.416, 95% CI: 0.289–0.601, P<0.001) were identified as independent protective factors for SSI. Conclusions:It is important to consider the nutritional status in the perioperative period of patients undergoing EAS. Preoperative skin preparation should be conducted and, whenever possible, laparoscope or robot-assisted surgery. Duration of surgery should be as short as possible while maintaining surgery quality and improving patient care.

Objective:To investigate the risk factors of surgical site infection (SSI) after colorectal surgery, and to establish and validate a risk prediction model nomogram.Methods:An observational study was conducted to retrospectively collect data of 6527 patients aged ≥16 years who underwent colorectal surgery in 56 domestic hospitals from March 1, 2021 to February 28, 2022 from the national Surgical Site Infection Surveillance network. The incidence of SSI after surgery was 2.3% (149/6527). According to the ratio of 7:3, 6527 patients were randomly divided into the modeling cohort (4568 cases) and the validation cohort (1959 cases), and there was no statistically significant difference between the two datasets ( P>0.05). Univariate analysis was performed using t test /Mann-Whitney U test /χ 2 test. Multivariate analysis was performed using binary logistic regression to establish a preliminary model and select variables using Lasso analysis to establish an optimized model nomogram. The discrimination and calibration of the model were evaluated by ROC curve, calibration curve, and Hosmer-Lemeshow test. AUC value>0.7 is considered a good discrimination of the model. The Bootstrap method (repeated self-sampling 1000 times) was used to verify the constructed model internally and externally to evaluate the accuracy of the constructed model. Results:Multivariate analysis showed that history of chronic liver disease (OR=3.626, 95%CI: 1.297-10.137, P<0.001) and kidney disease (OR=1.567,95%CI:1.042-2.357, P=0.038), surgical antibiotic prophylaxis (OR=1.564, 95%CI:1.038-2.357, P=0.035), and emergency surgery (OR=1.432,95%CI: 1.089-1.885, P=0.021), open surgery (OR=1.418, 95%CI:1.045-1.924, P=0.042), preoperative stoma (OR=3.310, 95%CI:1.542-7.105, P<0.001), postoperative stoma (OR=2.323,95%CI: 1.537-8.134, P<0.001), surgical incision type above grade II (OR=1.619,95%CI:1.097-2.375, P=0.014), and each unit increase in total bilirubin (OR=1.003,95%CI:-0.994-1.012, P=0.238), alanine aminotransferase (OR=1.006, 95%CI:1.001-1.011, P=0.032), blood urea nitrogen (OR=1.003,95%CI:0.995-1.011, P=0.310), blood glucose (OR=1.024, 95%CI:1.005-1.043, P=0.027), C-reactive protein (OR=1.007, 95%CI:1.003-1.011, P<0.001), length of incision (OR=1.042, 95%CI:1.002-1.087, P=0.031), surgical duration (OR=1.003,95%CI:1.001-1.005, P=0.017), and surgical blood loss (OR=1.001,95%CI: 1.000-1.002, P=0.045) were risk factors for SSI after colorectal surgery. Each unit increase in albumin level (OR=0.969,95%CI:0.941-0.998, P=0.036) was an independent protective factor for SSI after colorectal surgery. The area under the curve of the optimized model obtained by internal and external validation were 0.768 (95%CI: 0.723-0.813) and 0.753 (95%CI: 0.680-0.832), respectively. The predicted value of the calibration curve was basically consistent with the actual value. Conclusions:The risk prediction model for SSI after colorectal surgery constructed in this study has good discrimination and calibration. The nomogram created in this model can provide an evaluation basis for the observed rate and expected event rate of SSI after clinical colorectal surgery.

Objective:We investigated the incidence of surgical site infection (SSI) following emergency abdominal surgery (EAS) in China and further explored its risk factors, providing a reference for preventing and controlling SSI after EAS.Methods:This was an observational study. Data of patients who had undergone EAS and been enrolled in the Chinese SSI Surveillance Program during 2018–2021were retrospectively analyzed. All included patients had been followed up for 30 days after surgery. The analyzed data consisted of relevant patient characteristics and perioperative clinical data, including preoperative hemoglobin, albumin, and blood glucose concentrations, American Society of Anesthesiologists (ASA) score, grade of surgical incision, intestinal preparation, skin preparation, location of surgical site, approach, and duration. The primary outcome was the incidence of SSI occurring within 30 days following EAS. SSI was defined as both superficial and deep incisional infections and organ/space infections, diagnoses being supported by results of microbiological culture of secretions and pus. Secondary outcomes included 30-day postoperative mortality rates, length of stay in the intensive care unit (ICU), duration of postoperative hospitalization, and associated costs. The patients were classified into two groups, SSI and non-SSI, based on whether an infection had been diagnosed. Univariate and multivariate logistic regression analyses were performed to identify risk factors associated with SSI following EAS.Results:The study cohort comprised 5491 patients who had undergone EAS, comprising 3169 male and 2322 female patients. SSIs were diagnosed in 168 (3.1%) patients after EAS (SSI group); thus, the non-SSI group consisted of 5323 patients. The SSIs comprised superficial incision infections in 69 (41.1%), deep incision infections in 51 (30.4%), and organ or space infections in 48 (28.6%). Cultures of secretions and pus were positive in 115 (68.5%) cases. The most frequently detected organism was Escherichia coli (47/115; 40.9%). There were no significant differences in sex or body mass index between the SSI and non-SSI groups (both P>0.05). However, the proportion of individuals aged 60 years or older was significantly greater in the SSI than in the non-SSI group (49.4% [83/168] vs. 27.5% [1464/5323), χ 2=38.604, P<0.001). Compared with the non-SSI group, the SSI group had greater proportions of patients with diabetes (11.9% [20/168] vs. 4.8% [258/5323], χ 2=16.878, P<0.001), hypertension (25.6% [43/168] vs. 12.2% [649/5323], χ 2=26.562, P<0.001); hemoglobin <110 g/L (27.4% [46/168] vs. 13.1% [697/5323], χ 2=28.411, P<0.001), and albuminemia <30 g/L (24.4% [41/168] vs. 5.9% [316/5323], χ 2=91.352, P<0.001), and a reduced rate of preoperative skin preparation (66.7% [112/168] vs. 75.9% [4039/5323], χ 2=7.491, P=0.006). Furthermore, fewer patients in the SSI group had preoperative ASA scores of between one and two (56.0% [94/168] vs. 88.7% [4724/5323], χ 2=162.869, P<0.001) in the non-SSI group. The incidences of contaminated and infected incisions were greater in the SSI group (63.1% [106/168] vs. 38.6% [2056/5323], χ 2=40.854, P<0.001). There was a significant difference in surgical site distribution between the SSI and non-SSI groups (small intestine 29.8% [50/168] vs. 10.6% [565/5323], colorectal 26.2% [44/168] vs. 5.6% [298/5 323], and appendix 24.4% [41/168] vs. 65.1% [3465/5323]) χ 2=167.897, P<0.001), respectively. There was a significantly lower proportion of laparoscope or robotic surgery in the non-SSI group (24.4 % [41/168] vs. 74.2% [3949/5323], χ 2=203.199, P<0.001); the percentage of operations of duration less than 2 hours was significantly lower in the SSI than non-SSI group (35.7% [60/168] vs. 77.4% [4119/5323], χ 2=155.487, P<0.001). As to clinical outcomes, there was a higher 30-day postoperative mortality rate (3.0%[5/168] vs. 0.2%[10/5323], χ 2=36.807, P<0.001) and higher postoperative ICU occupancy rate (41.7% [70/168] vs. 19.7% [1046/5323], χ 2=48.748, P<0.001) in the SSI group. The median length of stay in the ICU (0[2] vs. 0[0] days, U=328597.000, P<0.001), median total length of stay after surgery (16[13] vs. 6[5] days, U=128146.000, P<0.001), and median hospitalization cost (ten thousand yuan, 4.7[4.4] vs. 1.7[1.8], U=175965.000, P<0.001) were all significantly greater in the SSI group. Multivariate logistic regression analysis revealed that the absence of skin preparation before surgery (OR=2.435,95%CI: 1.690–3.508, P<0.001), preoperative albuminemia <30 g/L (OR=1.680, 95%CI: 1.081–2.610, P=0.021), contaminated or infected incisions (OR=3.031, 95%CI: 2.151–4.271, P<0.001), and laparotomy (OR=3.436, 95% CI: 2.123–5.564, P<0.001) were independent risk factors of SSI. Operative duration less than 2 hours (OR=0.465, 95%CI: 0.312–0.695, P<0.001) and ASA score of 1–2 (OR=0.416, 95% CI: 0.289–0.601, P<0.001) were identified as independent protective factors for SSI. Conclusions:It is important to consider the nutritional status in the perioperative period of patients undergoing EAS. Preoperative skin preparation should be conducted and, whenever possible, laparoscope or robot-assisted surgery. Duration of surgery should be as short as possible while maintaining surgery quality and improving patient care.

Objective:To investigate the risk factors of surgical site infection (SSI) after colorectal surgery, and to establish and validate a risk prediction model nomogram.Methods:An observational study was conducted to retrospectively collect data of 6527 patients aged ≥16 years who underwent colorectal surgery in 56 domestic hospitals from March 1, 2021 to February 28, 2022 from the national Surgical Site Infection Surveillance network. The incidence of SSI after surgery was 2.3% (149/6527). According to the ratio of 7:3, 6527 patients were randomly divided into the modeling cohort (4568 cases) and the validation cohort (1959 cases), and there was no statistically significant difference between the two datasets ( P>0.05). Univariate analysis was performed using t test /Mann-Whitney U test /χ 2 test. Multivariate analysis was performed using binary logistic regression to establish a preliminary model and select variables using Lasso analysis to establish an optimized model nomogram. The discrimination and calibration of the model were evaluated by ROC curve, calibration curve, and Hosmer-Lemeshow test. AUC value>0.7 is considered a good discrimination of the model. The Bootstrap method (repeated self-sampling 1000 times) was used to verify the constructed model internally and externally to evaluate the accuracy of the constructed model. Results:Multivariate analysis showed that history of chronic liver disease (OR=3.626, 95%CI: 1.297-10.137, P<0.001) and kidney disease (OR=1.567,95%CI:1.042-2.357, P=0.038), surgical antibiotic prophylaxis (OR=1.564, 95%CI:1.038-2.357, P=0.035), and emergency surgery (OR=1.432,95%CI: 1.089-1.885, P=0.021), open surgery (OR=1.418, 95%CI:1.045-1.924, P=0.042), preoperative stoma (OR=3.310, 95%CI:1.542-7.105, P<0.001), postoperative stoma (OR=2.323,95%CI: 1.537-8.134, P<0.001), surgical incision type above grade II (OR=1.619,95%CI:1.097-2.375, P=0.014), and each unit increase in total bilirubin (OR=1.003,95%CI:-0.994-1.012, P=0.238), alanine aminotransferase (OR=1.006, 95%CI:1.001-1.011, P=0.032), blood urea nitrogen (OR=1.003,95%CI:0.995-1.011, P=0.310), blood glucose (OR=1.024, 95%CI:1.005-1.043, P=0.027), C-reactive protein (OR=1.007, 95%CI:1.003-1.011, P<0.001), length of incision (OR=1.042, 95%CI:1.002-1.087, P=0.031), surgical duration (OR=1.003,95%CI:1.001-1.005, P=0.017), and surgical blood loss (OR=1.001,95%CI: 1.000-1.002, P=0.045) were risk factors for SSI after colorectal surgery. Each unit increase in albumin level (OR=0.969,95%CI:0.941-0.998, P=0.036) was an independent protective factor for SSI after colorectal surgery. The area under the curve of the optimized model obtained by internal and external validation were 0.768 (95%CI: 0.723-0.813) and 0.753 (95%CI: 0.680-0.832), respectively. The predicted value of the calibration curve was basically consistent with the actual value. Conclusions:The risk prediction model for SSI after colorectal surgery constructed in this study has good discrimination and calibration. The nomogram created in this model can provide an evaluation basis for the observed rate and expected event rate of SSI after clinical colorectal surgery.

Objective:To analyze clinical characteristics of recurrent appendicitis.Methods:A retrospective cohort study was carried out. Clinical data of patients who underwent appendectomy due to acute appendicitis confirmed by pathology in the Affiliated Hospital of Qingdao University from January 2011 to December 2015 were analyzed retrospectively. Exclusion criteria: (1) age of less than 18 years;(2) chronic appendicitis; (3) periappendiceal abscess; (4) appendiceal mucocele or mucinous neoplasms; (5) appendiceal neuroendocrine tumors or cancers; (6) appendicitis during pregnancy; (7) concurrent AIDS, hematological disease, autoimmune disease, inflammatory bowel disease or advanced cancer; (8) other simultaneous surgery. A total of 373 patients were enrolled the study. These patients were divided into the recurrent group (133 cases) and the first episode group (240 cases) according to the previous history of antibiotic therapy for acute appendicitis. The prevalence of recurrent appendicitis was calculated, and the clinical characteristics were analyzed, including gender, age, comorbidities and preoperative CT images.Results:Of 373 patients, 209 were male and 164 were female, with a median age of 42 (18 to 88) years. Median recurrent time of the recurrent group was 4 (1 to 60) months. Compared to the first episode group, the recurrent group had higher proportion of age <50 years [71.4% (95/133) vs. 57.5% (138/240), χ 2=7.081, P=0.008], higher proportion of concurrent diabetes [13.5% (18/133) vs. 5.4% (13/240), χ 2=7.399, P=0.007], shorter onset time [(41.7±13.6) hours vs. (59.4±56.2) hours, t=-3.286, P=0.001], lower proportion of abdominal tension and rebound pain [57.9% (77/133) vs. 66.7% (160/240), χ 2=5.065, P=0.024], lower score of modified Alvarado score [(5.6±1.9) point vs. (6.1±1.9) point, t=-2.417, P=0.016], lower WBC count [(10.5±4.6) ×10 9/L vs. (11.5±4.5)×10 9/L, t=-1.190, P=0.047], higher percentage of lymphocyte [(19.4±14.7)% vs. (16.1±13.3)%, t=2.069, P=0.039]. In the recurrent group, ratio of length of removed appendix ≥7 cm was higher as compared with the first episode group [44.4% (59/133) vs. 32.9% (79/240), χ 2=4.808, P=0.028], while the ratio of complicated appendicitis was significantly lower [8.3% (11/133) vs. 22.9% (55/240), χ 2=10.823, P=0.001]. CT images were available in 129 patients, intraluminal appendicoliths was found in 19 of 50 patients (38%) in the recurrent group, while in 16 of 79 patients (20.3%) in the first episode group, and there was statistically significant difference between the two groups (χ 2=4.880, P=0.027). Conclusions:Clinical characteristics of recurrent acute appendicitis include age less than 50 years, concurrent diabetes, short onset time, less abdominal tension or rebound pain, low modified Alvarado score, low WBC count, high percentage of lymphocyte, appendix length longer than 7 cm, non-complicated appendicitis and intraluminal appendicoliths.

Most abdominal infections are mixed infections caused by aerobic and anaerobic bacteria. Anaerobic infections are characterized by rancid secretions or abscess formation. Early implementation of source control is the key in the treatment of abdominal anaerobic infections. Damage control should be followed as one of the principles of surgical treatment. As the in vitro isolation and culture of anaerobic bacteria as well as its drug sensitivity test are time-consuming and sometimes inaccurate, the treatment of anaerobic bacteria infection is mostly empirical. Anti-infective therapy should be employed once anaerobic bacteria infection is confirmed. Ertapenem, Mosifloxacin, and Cefoperazone-sulbactam can be used for first-line monotherapy, while combination therapy can use second- or third-generation Cephalosporin, Quinolones plus Nitroimidazoles. Nutritional support and anti-shock treatment should not be neglected when implementing surgical control of infection source and antimicrobial therapy. Considering the increasing drug resistance of anaerobic bacteria, and the higher drug resistance rate in China as compared to western countries, the choice of antibiotics should be made rationally and based on epidemiological characteristics of anaerobic bacteria in different regions.

Objective:Surgical site infection (SSI) can markedly prolong postoperative hospital stay, aggravate the burden on patients and society, even endanger the life of patients. This study aims to investigate the national incidence of SSI following abdominal surgery and to analyze the related risk factors in order to provide reference for the control and prevention of SSI following abdominal surgery.Methods:A multicenter cross-sectional study was conducted. Clinical data of all the adult patients undergoing abdominal surgery in 68 hospitals across the country from June 1 to 30, 2020 were collected, including demographic characteristics, clinical parameters during the perioperative period, and the results of microbial culture of infected incisions. The primary outcome was the incidence of SSI within postoperative 30 days, and the secondary outcomes were ICU stay, postoperative hospital stay, cost of hospitalization and the mortality within postoperative 30-day. Multivariable logistic regression was used to analyze risk factors of SSI after abdominal surgery.Results:A total of 5560 patients undergoing abdominal surgery were included, and 163 cases (2.9%) developed SSI after surgery, including 98 cases (60.1%) with organ/space infections, 19 cases (11.7%) with deep incisional infections, and 46 cases (28.2%) with superficial incisional infections. The results from microbial culture showed that Escherichia coli was the main pathogen of SSI. Multivariate analysis revealed hypertension (OR=1.792, 95% CI: 1.194-2.687, P=0.005), small intestine as surgical site (OR=6.911, 95% CI: 1.846-25.878, P=0.004), surgical duration (OR=1.002, 95% CI: 1.001-1.003, P<0.001), and surgical incision grade (contaminated incision: OR=3.212, 95% CI: 1.495-6.903, P=0.003; Infection incision: OR=11.562, 95%CI: 3.777-35.391, P<0.001) were risk factors for SSI, while laparoscopic or robotic surgery (OR=0.564, 95%CI: 0.376-0.846, P=0.006) and increased preoperative albumin level (OR=0.920, 95%CI: 0.888-0.952, P<0.001) were protective factors for SSI. In addition, as compared to non-SSI patients, the SSI patients had significantly higher rate of ICU stay [26.4% (43/163) vs. 9.5% (514/5397), χ 2=54.999, P<0.001] and mortality within postoperative 30-day [1.84% (3/163) vs.0.01% (5/5397), χ 2=33.642, P<0.001], longer ICU stay (median: 0 vs. 0, U=518 414, P<0.001), postoperative hospital stay (median: 17 days vs. 7 days, U=656 386, P<0.001), and total duration of hospitalization (median: 25 days vs. 12 days, U=648 129, P<0.001), and higher hospitalization costs (median: 71 000 yuan vs. 39 000 yuan, U=557 966, P<0.001). Conclusions:The incidence of SSI after abdominal surgery is 2.9%. In order to reduce the incidence of postoperative SSI, hypoproteinemia should be corrected before surgery, laparoscopic or robotic surgery should be selected when feasible, and the operating time should be minimized. More attentions should be paid and nursing should be strengthened for those patients with hypertension, small bowel surgery and seriously contaminated incision during the perioperative period.