Objective To explore the microbiological characteristics of Staphylococcus aureus(S.aureus)with no-vel incomplete hemolytic phenotype(SIHP).Methods Hemolytic phenotypes were detected and categorized by u-sing the three-point inoculation method.A total of 11 novel SIHP and 33 randomly matched S.aureus with com-plete hemolytic phenotype(SCHP)were included.Antibiotic susceptibility test was performed using broth microdi-lution method.Coagulase test was performed with freeze-dried rabbit plasma.Catalase activity was detected by slide catalase test.Expression of hemolysin genes was detected by qRT-PCR.Toxicity to human red blood cells was as-sessed by microplate method.Microplate biofilm formation was measured using crystal violet staining method.Growth kinetic determination was performed through microcultivation assay.Results Compared with SCHP,the expression profiles of the four hemolysin genes(hla,hlb,hlc,and hld)in the new SIHP were different.The new SIHP had higher resistance rates to penicillin,oxacillin,gentamicin,quinolones,clindamycin,and trimethoprim-sulfamethoxazole.Furthermore,the new SIHP had stronger hemolytic toxicity,plasma coagulase activity,and bio-film formation ability.Additionally,the new SIHP grown faster in the logarithmic phase.Conclusion Taken to-gether,the microbiological characteristics of the new SIHP are different from those of SCHP,including stronger an-tibiotic resistance and pathogenicity,which should be paid more attention by clinicians.

Objective:To explore the effect of case study combined with scenario simulation in teaching clinical internship of radiation oncology.Methods:This study selected 144 undergraduate students majoring in clinical medicine who interned at the Department of Radiotherapy at Sun Yat-sen University Cancer Center from November 2022 to May 2023 as the research subjects. They were randomly divided into a control group and an observation group. The control group received traditional teaching, while the observation group received case study combined with scenario simulation teaching, with 72 students in each group. The two groups of trainees were evaluated for theoretical and skill assessment scores, core competencies, and teaching satisfaction. The t-test and chi-square test were performed using SPSS 22.0. Results:The theoretical and skill scores of the trainees in the observation group [(88.27±3.40) and (92.69±3.65)] were higher than those in the control group [(83.01±10.38) and (87.20±3.74)], and the differences were statistically significant. Compared with the control group, the observation group showed higher core competency scores in eight dimensions, including learning initiative and enthusiasm, knowledge comprehension ability, critical thinking ability, clinical specialty practice ability, analytical and problem-solving ability, doctor-patient communication, professional ethics, and teamwork ability, and the differences were statistically significant ( P<0.05). The satisfaction scores of the observation group trainees of teaching plan, teaching content, teaching methods, teaching results, and teaching ability were higher than those of the control group, and the differences were statistically significant ( P<0.05). Conclusions:The application of case study combined with scenario simulation teaching clinical internship of radiation oncology can help improve the theoretical and skill scores of medical students, as well as their core competencies and teaching satisfaction. This is a teaching method worthy of application and promotion.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in healthcare facilities in major regions of China in 2023.Methods Clinical isolates collected from 73 hospitals across China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2023 Clinical & Laboratory Standards Institute (CLSI) breakpoints.Results A total of 445199 clinical isolates were collected in 2023,of which 29.0％ were gram-positive and 71.0％ were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species (excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi) (MRSA,MRSE and MRCNS) was 29.6％,81.9％ and 78.5％,respectively.Methicillin-resistant strains showed significantly higher resistance rates to most antimicrobial agents than methicillin-susceptible strains (MSSA,MSSE and MSCNS).Overall,92.9％ of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 91.4％ of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis had significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 93.1％ in the isolates from children and and 95.9％ in the isolates from adults.The resistance rate to carbapenems was lower than 15.0％ for most Enterobacterales species except for Klebsiella,22.5％ and 23.6％ of which were resistant to imipenem and meropenem,respectively .Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.6％ to 10.0％.The resistance rate to imipenem and meropenem was 21.9％ and 17.4％ for Pseudomonas aeruginosa,respectively,and 67.5％ and 68.1％ for Acinetobacter baumannii,respectively.Conclusions Increasing resistance to the commonly used antimicrobial agents is still observed in clinical bacterial isolates.However,the prevalence of important crabapenem-resistant organisms such as crabapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a slightly decreasing trend.This finding suggests that strengthening bacterial resistance surveillance and multidisciplinary linkage are important for preventing the occurrence and development of bacterial resistance.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.

Objective:To explore the effect of case study combined with scenario simulation in teaching clinical internship of radiation oncology.Methods:This study selected 144 undergraduate students majoring in clinical medicine who interned at the Department of Radiotherapy at Sun Yat-sen University Cancer Center from November 2022 to May 2023 as the research subjects. They were randomly divided into a control group and an observation group. The control group received traditional teaching, while the observation group received case study combined with scenario simulation teaching, with 72 students in each group. The two groups of trainees were evaluated for theoretical and skill assessment scores, core competencies, and teaching satisfaction. The t-test and chi-square test were performed using SPSS 22.0. Results:The theoretical and skill scores of the trainees in the observation group [(88.27±3.40) and (92.69±3.65)] were higher than those in the control group [(83.01±10.38) and (87.20±3.74)], and the differences were statistically significant. Compared with the control group, the observation group showed higher core competency scores in eight dimensions, including learning initiative and enthusiasm, knowledge comprehension ability, critical thinking ability, clinical specialty practice ability, analytical and problem-solving ability, doctor-patient communication, professional ethics, and teamwork ability, and the differences were statistically significant ( P<0.05). The satisfaction scores of the observation group trainees of teaching plan, teaching content, teaching methods, teaching results, and teaching ability were higher than those of the control group, and the differences were statistically significant ( P<0.05). Conclusions:The application of case study combined with scenario simulation teaching clinical internship of radiation oncology can help improve the theoretical and skill scores of medical students, as well as their core competencies and teaching satisfaction. This is a teaching method worthy of application and promotion.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in healthcare facilities in major regions of China in 2023.Methods Clinical isolates collected from 73 hospitals across China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2023 Clinical & Laboratory Standards Institute (CLSI) breakpoints.Results A total of 445199 clinical isolates were collected in 2023,of which 29.0％ were gram-positive and 71.0％ were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species (excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi) (MRSA,MRSE and MRCNS) was 29.6％,81.9％ and 78.5％,respectively.Methicillin-resistant strains showed significantly higher resistance rates to most antimicrobial agents than methicillin-susceptible strains (MSSA,MSSE and MSCNS).Overall,92.9％ of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 91.4％ of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis had significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 93.1％ in the isolates from children and and 95.9％ in the isolates from adults.The resistance rate to carbapenems was lower than 15.0％ for most Enterobacterales species except for Klebsiella,22.5％ and 23.6％ of which were resistant to imipenem and meropenem,respectively .Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.6％ to 10.0％.The resistance rate to imipenem and meropenem was 21.9％ and 17.4％ for Pseudomonas aeruginosa,respectively,and 67.5％ and 68.1％ for Acinetobacter baumannii,respectively.Conclusions Increasing resistance to the commonly used antimicrobial agents is still observed in clinical bacterial isolates.However,the prevalence of important crabapenem-resistant organisms such as crabapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a slightly decreasing trend.This finding suggests that strengthening bacterial resistance surveillance and multidisciplinary linkage are important for preventing the occurrence and development of bacterial resistance.

Objective:To compare 5-year overall survival (OS) and disease free survival (DFS) between preoperative three dimensional conformal radiotherapy (3DCRT) and volumetric medulated arc therapy (VMAT) concurrently combined with chemotherapy for locally advanced rectum cancer (LARC), and analyze the value of induction and/or consolidation chemotherapy in these circumstances.Methods:334 patients with LARC treated with preoperative 3DCRT (172 cases) and VMAT (162 cases) concurrently combined with chemotherapy, main protocol XELOX (capecitabine plus oxaplatin), and subsequent surgery in Sun Yat-sen University from May 2007 to April 2013 were retrospectively analyzed. The radiation prescription dose for VMAT group was 50 Gy 25 fractions for planning target volume1(PTV 1), and 46 Gy 25 fractions for PTV 2. The radiation prescription dose for 3DCRT group was 46 Gy 23 fractions for PTV 2. One hundred and eighty-five cases of all received preoperative concurrent chemoradiotherapy (namely, CCRT group), 149 cases received preoperative concurrent chemoradiotherapy plus median 2 courses (1-7 courses) induction and/or consolidation chemotherapy (namely, CCRT±induction chemotherapy±consolidation chemotherapy group), whose main chemotherapy protocol was XELOX. Difference of 5-year OS and DFS between 3DCRT and VMAT group was compared. The rate differences of acute toxicity during chemoradiotherapy, postoperative complications, ypCR, and survival between CCRT group and CCRT±induction chemotherapy±consolidation chemotherapy group were analyzed. Results:After a median follow-up of 62.3 months (2.4-119months) for the 334 patients, no any significant difference for 5-year OS (79.0% vs. 83.2%, P=0.442) and 5-year DFS (77.0% vs. 82.1%, P=0.231) between 3DCRT and VMAT group was observed. There was no any significant difference for the Grade 3 hematological toxicity (7.0% vs. 12.1%, P=0.114) and non-hematological toxicity (14.1% vs. 16.8%, P=0.491) during chemoradiotherapy, postoperative complications (17.3% vs. 17.4%, P=0.971), ypCR rate (25.4% vs. 30.2%, P=0.329), 5-year OS (80.5% vs. 82.0%, P=0.714) and 5-year DFS (78.8% vs. 81%, P=0.479) between CCRT group and CCRT±induction chemotherapy±consolidation chemotherapy group. Conclusions:Compared with 3DCRT, the physics advantage of VMAT technique does not significantly convert into clinical benefits and improve 5-year OS and DFS, even further boosting radiation dose to the gross tumor volume. It is safe for median 2 courses of induction and/or consolidation chemotherapy before and or after preoperative concurrent chemoradiotherapy in the treatment of LARC, though it does not significantly improve ypCR rate and survival.

Objective:To compare long-term efficacy between watch and wait (W&W) strategy and total mesorectal excision (TME) in patients who were diagnosed with locally advanced rectal cancer (LARC) and attained clinical complete response (cCR) after neoadjuvant chemoradiotherapy (nCRT).Methods:A retrospective cohort study was carried out. A total of 238 patients with stage II-III LARC exhibiting cCR after nCRT in Sun Yat-sen University Cancer Center from September 16, 2010 to January 9, 2018 were enrolled. Patients who were diagnosed with other malignant tumor within 5 years, did not receive regular follow-up in our center for more than 1 year and had no complete examination items after nCRT were excluded. Of 238 patients, 151 were male and 87 were female with a median age of 57 (27-83) years old. According to TNM stage, 61 cases were cII, 177 cases were cIII. Concurrent chemoradiotherapy (CCRT) was performed in 20 patients. CCRT plus induction/consolidated chemotherapy was performed in 218 patients. Intensity-modulated radiotherapy (IMRT) was applied to radiotherapy. The median radiation dose was 50 Gy/25 Fr for both the primary tumor and clinical target volumes, and the total dose was 45.0 to 50.6 Gy for 227 patients. In 27 patients, single-agent fluorouracil or capecitabine was used as concurrent chemotherapy. But in the other 211 patients, a combined regimen of oxaliplatin and fluorouracil or capecitabine was used. After nCRT, 59 and 179 patients received W&W (W&W group) and TME 6-12 weeks later (TME group), respectively. After the ending of treatment, patient was interviewed one time every 3 months and after 3 years, one time every six months. Overall survival (OS) rate, distant-metastasis-free survival (DMFS) rate, and local-recurrence-free survival (LRFS) rate were compared between two groups. The salvage treatment and sphincter preservation rate were analyzed. The survival curve was drawn with Kaplan-Meier method and evaluated by log-rank method.Results:In the cases treated with TME, the median interval from nCRT to surgery was 59 days. The postoperative pCR rate was 63.1%(113/179). The median follow-up time of the whole cohort was 41.8 (12.0-99.0) months. The 3-year and 5-year OS rates were 98.4% and 96.5%; the 3-year and 5-year LRFS rates were 96.5% and 96.5%; the 3- and 5-year DMFS rates were 91.0% and 87.9%, respectively. The 3-year OS rates in the W&W group and the TME group were 100% and 97.9%; the 5-year OS rates in W&W group and the TME group were 90.6% and 97.9% ( P=0.339); The 3-year local recurrence rate (LRR) in the W&W group was 12.9% (7 cases recurred within 2 years), which was significanthy higher then that in the TME group (0.6%, P=0.003). Salvage surgery was successful in 5/6 cases. After salvage surgery, LRFS rate was not significantly different between the two groups ( P=0.137). The 3-year DMFS rate in the W&W group and the TME group were 88.4% and 81.1%, whose difference was not significant ( P=0.593). Recurrence with simultaneous metastasis was seen in 3/7 cases of the W&W group. The sphincter was preserved in 89.8% (53/59) of patients in the W&W group, which was significantly higher than 73.7% (132/179) in the TME group ( P<0.001). When distance of tumor from the anal verge was ≤ 5 cm, the sphincter preservation rate (SPR) in the W&W group was 88.0% (44/50), which was significantly higher than the 54.4% (56/103) in the TME group ( P<0.001). Conclusions:W&W is safe and feasible for patients with LARC and cCR after nCRT. The results should be verified by further clinical trials.

Objective:To compare long-term efficacy between watch and wait (W&W) strategy and total mesorectal excision (TME) in patients who were diagnosed with locally advanced rectal cancer (LARC) and attained clinical complete response (cCR) after neoadjuvant chemoradiotherapy (nCRT).Methods:A retrospective cohort study was carried out. A total of 238 patients with stage II-III LARC exhibiting cCR after nCRT in Sun Yat-sen University Cancer Center from September 16, 2010 to January 9, 2018 were enrolled. Patients who were diagnosed with other malignant tumor within 5 years, did not receive regular follow-up in our center for more than 1 year and had no complete examination items after nCRT were excluded. Of 238 patients, 151 were male and 87 were female with a median age of 57 (27-83) years old. According to TNM stage, 61 cases were cII, 177 cases were cIII. Concurrent chemoradiotherapy (CCRT) was performed in 20 patients. CCRT plus induction/consolidated chemotherapy was performed in 218 patients. Intensity-modulated radiotherapy (IMRT) was applied to radiotherapy. The median radiation dose was 50 Gy/25 Fr for both the primary tumor and clinical target volumes, and the total dose was 45.0 to 50.6 Gy for 227 patients. In 27 patients, single-agent fluorouracil or capecitabine was used as concurrent chemotherapy. But in the other 211 patients, a combined regimen of oxaliplatin and fluorouracil or capecitabine was used. After nCRT, 59 and 179 patients received W&W (W&W group) and TME 6-12 weeks later (TME group), respectively. After the ending of treatment, patient was interviewed one time every 3 months and after 3 years, one time every six months. Overall survival (OS) rate, distant-metastasis-free survival (DMFS) rate, and local-recurrence-free survival (LRFS) rate were compared between two groups. The salvage treatment and sphincter preservation rate were analyzed. The survival curve was drawn with Kaplan-Meier method and evaluated by log-rank method.Results:In the cases treated with TME, the median interval from nCRT to surgery was 59 days. The postoperative pCR rate was 63.1%(113/179). The median follow-up time of the whole cohort was 41.8 (12.0-99.0) months. The 3-year and 5-year OS rates were 98.4% and 96.5%; the 3-year and 5-year LRFS rates were 96.5% and 96.5%; the 3- and 5-year DMFS rates were 91.0% and 87.9%, respectively. The 3-year OS rates in the W&W group and the TME group were 100% and 97.9%; the 5-year OS rates in W&W group and the TME group were 90.6% and 97.9% ( P=0.339); The 3-year local recurrence rate (LRR) in the W&W group was 12.9% (7 cases recurred within 2 years), which was significanthy higher then that in the TME group (0.6%, P=0.003). Salvage surgery was successful in 5/6 cases. After salvage surgery, LRFS rate was not significantly different between the two groups ( P=0.137). The 3-year DMFS rate in the W&W group and the TME group were 88.4% and 81.1%, whose difference was not significant ( P=0.593). Recurrence with simultaneous metastasis was seen in 3/7 cases of the W&W group. The sphincter was preserved in 89.8% (53/59) of patients in the W&W group, which was significantly higher than 73.7% (132/179) in the TME group ( P<0.001). When distance of tumor from the anal verge was ≤ 5 cm, the sphincter preservation rate (SPR) in the W&W group was 88.0% (44/50), which was significantly higher than the 54.4% (56/103) in the TME group ( P<0.001). Conclusions:W&W is safe and feasible for patients with LARC and cCR after nCRT. The results should be verified by further clinical trials.

Objective To investigate the feasibility of non-operative management (NOM) by comparing the therapeutic effects between NOM and total mesorectal excision (TME) for rectal cancer patients with clinical complete response (cCR) after neo-adjuvant chemoradiotherapy.Methods A total of 135 patients with stage Ⅱ/Ⅲ rectal cancer who obtained cCR after neo-adjuvant chemoradiotherapy in Sun Yat-sen University Cancer Center from 2006 to 2016 were recruited and assigned into the NOM (n =43) and standard operative management (SOM) groups (n=92).The local recurrence rate,accumulative local control (LC) rate after salvage therapy,disease-free survival (DFS),overall survival (OS) and sphincter preservation rate were statistically compared between two groups.Kaplan-Meier analysis and log-rank test were utilized to calculate the LC,OS and DFS.Chi-square test was performed to calculate the sphincter preservation rate.Results The mean follow-up duration was 39 months (range:10-127 months).Of 135 patients,the local recurrence rate and distant metastasis rate were 3.7％ and 11.1％,and the 3-year DFS and OS were 90.5％ and 97.0％.In the NOM and SOM groups,the 3-year DFS were 87％ and 93％,and the 5-year DFS were 73％ and 87％(P=0.089).The 3-year OS were 98％ and 99％,and the 5-year OS were 98％ and 97％ (P=0.578).In the NOM group,the local recurrence rate was 12％ (n =5),80％ of patients received salvage treatment and the accumulative LC rate was calculated as 98％.In the SOM group,the local recurrence rate was 0,which was significantly lower than that in the NOM group (P=0.O10).In the NOM group,the sphincter preservation rate was 93％,significantly higher compared with 70％ in the SOM group (P=0.030).Conclusions It is feasible for rectal cancer patients with cCR to receive NOM following neo-adjuvant chemoradiotherapy.Partial locally recurrent patients can be healed by timely salvage therapy,thereby averting TME and relevant complications and enhancing the quality of life of rectal cancer patients.