Objective:To evaluate the clinical performance of direct antimicrobial susceptibility test in blood culture-positive broth, and to provide a basis for optimizing the antibiotic use strategy in clinical bloodstream infection.Methods:A retrospective analysis was conducted on 780 blood culture-positive samples collected in Peking University People′s Hospital from May 2017 to December 2021. The direct antimicrobial susceptibility test was performed by disk diffusion method on blood culture-positive broth. The antimicrobial susceptibility breakpoints were in accordance with Clinical and Laboratory Standards Institute (CLSI) M100 S32 edition document.Results:In this study, a total of 331 strains of Gram-negative bacteria (139 strains of Escherichia coli, 79 strains of Klebsiella pneumoniae, 35 strains of Pseudomonas aeruginosa, 21 strains of Acinetobacter baumannii) and 396 strains of Gram-positive cocci (25 strains of Staphylococcus aureus, 316 strains of coagulase-negative staphylococci, 47 strains of Enterococcussp.) were collected, after excluding 53 cases with two or more isolates. Compared with the routine antimicrobial susceptibility test (AST), the rates of category agreement (CA), major error (ME), and very major error (VME) of Gram-negative bacteria were 86.0% (1368/1 591), 8.7% (139/1 591), and 0.5% (8/1 591), respectively. On the other hand, the CA%, ME%, and VME% of Gram-positive cocci were 89.2% (960/1 076), 7.5% (81/1 076), and 1% (11/1 076), respectively. Regarding the individual antimicrobial agents, the CA% of Escherichia coli was 16/17 for imipenem, 90.1% (109/121) for meropenem, and 70.8% (85/120) for cefepime. For Klebsiella pneumoniae, the CA% of was 10/13 for imipenem, 80.9% (55/68) for meropenem, and 80.3% (53/66) for cefepime. The CA% of meropenem in Pseudomonas aeruginosa and Acinetobacter baumannii were 96.0% (24/25) and 16/16. The CA% of linezolid and cefoxitin in Staphylococcus aureus were 100% (25/25) and 100% (24/24), respectively. The CA% of linezolid, cefoxitin and gentamicin in coagulase-negative staphylococci were 98.9% (269/272), 94.5% (277/293) and 71.6% (194/271) respectively. Finally, for Enterococcus sp., the CA% of vancomycin and ampicillin were 91.5% (43/47) and 94.7% (36/38), respectively. Conclusion:Compared with the conventional AST, the blood culture-positive broth direct AST exhibited high category agreement and low error rates for both Gram-negative bacteria and Gram-positive cocci, which can serve a rapid alternative for AST in cases of clinical bloodstream infection.

Objective:To evaluate whether the time to positive (TTP), handling time after positive alarm and turnaround time (TAT) of bacteremia blood culture can be shortened by optimizing blood culture workflow.Methods:This study was conducted retrospectively. Positive blood culture samples collected from Peking University People′s Hospital from January 1, 2014 to June 30, 2021 were analyzed in stages. In the traditional process stage of this study (2014), 502 bottles of positive blood culture samples were included in the analysis. In the first stage of process optimization (2016), the working time of staff was increased to 22:00, and 976 positive blood culture specimens were included in the analysis. In the second stage of process optimization (2018), the rapid identification process of MALDI-TOF MS was added, and a total of 1 029 bottles of positive blood culture samples were included. In the third stage of process optimization (2020) with the introduction of the new VIRTUO BACT/ALERT system. The difference of TTP, handling time after positive alarm and TAT of whole process in different stages of traditional process and process optimization were compared. All data were statistically significant when P<0.05 using rank-sum test. Results:In the traditional process stage (2014), the median quartile time of handling time after positive alarm was 55.70 (47.35, 68.45) h. In the first stage of process optimization (2016), the median quartile time of handling time after positive alarm was 47.25 (33.88, 59.96) h, and the handling time after positive alarm in the first stage of process optimization was significantly shorter than that in the traditional process stage ( Z=?10.734, P<0.001). In the second stage of process optimization (2018), the median quartile time for handling time after positive alarm was 47.18(36.41, 59.40) h, and 12.18% of the preliminary identification results of Gram-negative bacilli before 17:00 could be reported to the clinic before audit. In the third stage of process optimization (2020), the median quartile of TTP and TAT were 39.56 (21.52, 62.65) h and 78.16(64.68, 99.72) h respectively in the original BACT/ALERT 3D system. The new VIRTUO BACT/ALERT system had a median quartile of 37.03(21.08, 58.22) h for TTP and 73.41(62.88, 89.48) h for TAT. VIRTUO BACT/ALERT 3D had a significantly shorter TTP than BACT/ALERT 3D ( Z=?2.273, P=0.023), the TAT of VIRTUO BACT/ALERT system was significantly shorter than that of BACT/ALERT 3D system ( Z=?4.040, P<0.001). Conclusion:By improving the blood culture process of microbiology laboratory in many aspects and measures, the processing time of blood culture in each stage can be shortened and clinical benefits can be obtained.

Objective To evaluate the feasibility of using matrix-assisted laser desorption/ioniza-tion time-of-flight mass spectrometry(MALDI-TOF MS) in combination with Sepsityper Kit or serum-separa-ting gel tubes for identification of pathogenic organisms positive for blood culture. Methods A total of 153 clinical specimens with a positive result in blood culture were collected and tested with MALDI-TOF MS in combination with Sepsityper Kit or serum-separating gel tubes. Test results were compared with those by using culturing. Results The 153 positive blood culture specimens included 143 of single bacterial infection and 10 of multiple bacterial infections. The consistency rates at species and genus levels were 76.2% (109/153) and 7.8% (12/153) between Vitek 2 Compact method and MALDI-TOF MS combined with Sepsityper Kit,and 75.1% (101/153) and 8.5% (13/153) between Vitek 2 Compact method and MALDI-TOF MS combined with serum-separating gel tubes. In the identification of single bacterial infection specimens, the consistency rates of MALDI-TOF MS combined with Sepsityper Kit at species and genus levels were 95.2% (79/83) and 0% (0/83) for gram-negative bacteria,57.5% (27/47) and 23.4% (11/47) for gram-pos-itive bacteria and 33.3% (3/9) and 11.1% (1/9) for Candida,the consistency rates of MALDI-TOF MS combined with serum-separating gel tubes at species and genus levels were 90.4% (75/83) and 4.8% (4/83) for gram-negative bacteria,55.3% (26/47) and 14.9% (7/47) for gram-positive bacteria and 0% (0/9) and 22.2% (2/9) for Candida. MALDI-TOF MS combined with Sepsityper Kit was only consistent with Vitek 2 Compact method in the identification of one specimen of multiple bacterial infections. Conclu-sion MALDI-TOF MS in combination with Sepsityper Kit or serum-separating gel tubes can identify the pathogens positive for blood culture within one hour and is of high consistency with culturing. In comparison with the traditional identification method for positive blood cultures, MALDI-TOF MS combined with Sepsi-typer Kit or serum-separating gel tubes has the advantages of rapidity and easy operation, which meet the clinical needs of rapid diagnosis and timely and effective antibacterial treatment,and is of great value in clin-ical application.

Objective To evaluate the effect of three-point rigid internal fixation technique in reduction malarplasty for prominent malar complex.Methods From January of 2014 to January of 2017,45 patients with prominent malar complex were treated with double L shape osteotomy combined bony Z plasty and three-point rigid internal fixation for prominent malar complex.The preoperative and postoperative photographs were taken to monitor the contour improvement,the adverse effects were recorded,and 3D CT was used to assess the bone union situation at 6 months after operation.Results All the wounds got primary intention healing and no severe complication occured in perioperative period.3D CT showed good bone recovery 6 months after operation.Postoperative appearance of all cases showed that the width of middle face was efficiently reduced.All patients expressed high levels of satisfaction.Conclusions Reduction malarplasty with three-point rigid internal fixation for prominent malar complex is an effective and safe method for the treatment of prominent malar complex.

To dynamically investigate the distribution and antimicrobial resistance profiles of bacteremia pathogens isolated from different regions in China in 2011, 2013 and 2016. Non-repetitive isolates from nosocomial bloodstream infections were retrospectively collected and detected for antimicrobial susceptibility tests (AST) by agar dilution or microbroth dilution methods. Whonet 5.6 was used to analyze the AST data. Among 2 248 isolates, 1 657 (73.7%) were Gram-negative bacilli and 591 (26.3%) were Gram-positive cocci. The top five bacteremia pathogens were as follows, Escherichia coli (32.6%, 733/2 248), Klebsiella pneumoniae (14.5%, 327/2 248), Staphylococcus aureus (10.0%, 225/2 248), Acinetobacter baumannii (8.7%, 196/2 248) and Pseudomonas aeruginosa (6.2%, 140/2 248). Colistin (96.5%, 1 525/1 581, excluding innate resistant organisms), tigecycline (95.6%, 1 375/1 438, excluding innate resistant organisms), ceftazidine/clavulanate acid (89.2%, 1 112 /1 246), amikacin (86.4%, 1 382/1 599) and meropenem (85.7%, 1 376/1 605) showed relatively high susceptibility against Gram-negative bacilli. While tigecycline, teicoplanin and daptomycin (the susceptibility rates were 100.0%), vancomycin and linezolid (the susceptibility rates were 99.7%) demonstrated high susceptibility against Gram-positive cocci. The prevalence of extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriaceae were 50.6% (206/407), 49.8% (136/273) and 38.9% (167/429) in 2011, 2013 and 2016 respectively; carbapenem-non-susceptible Enterobacteriaceae were 2.2% (9/408), 4.0% (16/402) and 3.9% (17/439) in 2011, 2013 and 2016 respectively; The prevalence of multidrug-resistant A. baumannii (MDRA) was 76.4% (55/72) in 2011, 82.7% (43/52) in 2013 and 87.5% (63/72) in 2016, respectively. The prevalence of multidrug-resistant P. aeruginosa (MDRP) was 9.8% (5/51) in 2011, 20.0% (7/35) in 2013 and 13.0% (7/54) in 2016, respectively. The prevalence of methicillin-resistant S. aureus (MRSA) was 51.9% (41/79) in 2011, 29.7% (19/64) in 2013 and 31.7% (26/82) in 2016, respectively. The prevalence of high level gentamicin resistance (HLGR) of Enterococcus faecium and Enterococcus faecalis were 43.2% (48/111) and 40.9% (27/66), respectively. The predominant organism of carbapenem-non-susceptible Enterobacteriaceae was K. pneumoniae with its proportion of 57.1% (24/42). Among 30 tigecycline-non-susceptible Enterobacteriaceae, K. pneumoniae was the most popular organism with 76.7% (23/30). Among 39 colistin-resistant Enterobacteriaceae, E. coli, Enterobacter cloacae and K. pneumoniae were constituted with the percent of 43.6 (17/39), 35.9 (14/39) and 15.4 (6/39), respectively. The Gram-negative bacilli (E. coli and K. pneumoniae were the major organisms) were the major pathogens of nosocomial bacteremia, to which tigecycline, colistin and carbapenems kept with highly in vitro susceptibility. Whereas, among the Gram-positive cocci, S. aureus was the top 1 isolated organism, followed by E. faecium, to which tigecycline, daptomycin, linezolid, vancomycin and teicoplanin kept with highly in vitro susceptibility. Isolation of colistin-resistant Enterobacteriaceae, tigecycline-non-susceptible Enterobacteriaceae, linezolid- or vancomycin-non-susceptible Gram-positive cocci suggests more attention should be paid to these resistant organisms and dynamic surveillance was essential.

Objective To compare the efficacy between autologous fat and hyaluronic acid in filling nasolabial grooves.Methods Sixty patients who wanted improvement of nasolabial grooves were involved in the study.They were randomly and equally classified into two groups:autologous fat injection group and hyaluronic acid injection group.Photographs were taken before,half a year,and one year after injection.The nasolabial grooves were also graded before,half a year,and one year after injection.The grade improvement was obtained after postoperative grade minus preoperative grade.If the grade improvement was more than 1 grade,the treatment was regarded as effective to evaluate the outcome between the two methods.Results The results of the two groups were tested by SPSS 13.0 software.The effects of the two methods were not significantly different after half a year of filling (P＞0.05).The difference was significant one year after filling (P＜0.05).In autologous fat injection,the patients had a long and magnificant swelling and redness around the nasolabial grooves;on the contrary,the patients who underwent hyaluronic acid had slight and short-time local reaction like swelling and redness.No other serious complications were found in both the groups.Conclusions The effects of the autologous fat and the hyaluronic acid are equal after half a year of filling.The autologous fat has a longer effect in one year.Both methods are safe and effective.Surgeons can select the method accordingly.

Objective To analyze the clinical efficacy and technical key points of genioplasty for the deformities of the chin.Methods 153 patients with chin deformities were treated with the genioplasty,and the chin was moved in any direction,including sagittally,vertically and transversely;the key points of this procedure were summarized.Results There was no severe complication such as infection or nonunion observed.15 patients had ecchymosis and faded in 2 weeks;33 patients had hypaesthesia and recovered in 12 weeks.With the 12-24 months follow-up,all the patients healed well with satisfactory aesthetic results.Conclusions The genioplasty is a reliable and efficient method for the deformities of the chin,and it can significantly improve the appearance of the chin.

Objective To evaluate the clinical performance of the BACTEC Plus aerobic,BACTEC Lytic anaerobic,BacT/Alert aerobic and anaerobic blood culture media in detection of bloodstream infections.Methods Retrospective study was conducted.A total of four blood culture bottles from each inpatient with suspected bloodstream infections were collected and analyzed from June 2013 to September 2015 in Peking University People's Hospital.The four bottles,including BACTEC Plus aerobic,BACTEC Lytic anaerobic,BacT/Alert FA aerobic and BacT/Alert FN anaerobic media,and was incubated for 5 days in the BacT/Alert 3D and BACTEC FX instruments,respectively.Time to detection (TTD) and positive rate in detecting bacteria of the two systems were evaluated by Wilcoxon test and Chi-square test.Results Among 2 189 total cultures collected,20 were excluded because of blood shortage and 201 (9.27％) were positive for pathogens.The positive rates of BACTEC Plus aerobic media and BacT/Alert FA aerobic media were 75.3％ (140/186) and 69.4％ (129/186) (x2 =1.625,P=0.202),respectively.While,the positive rates of BacT/Alert FN anaerobic media and BACTEC Lytic anaerobic media were 81.8％ (99/121) and 63.6％ (77/121) for total organisms,respectively (x2 =10.083,P =0.001).A significant difference in TTD was detected in BACTEC Plus aerobic media[11.0 (8.0-16.0) h] and BacT/Alert FA aerobic media[13.9 (10.4-18.7) h] (Z =-5.240,P ＜ 0.001).BACTEC Lyric anaerobic media[8.0(7.0-10.0) h] had a shorter TTD (Z =-4.299,P ＜ 0.001) than BacT/Alert FN anaerobic media[11.3(9.3-12.7) h].The positive rates of BACTEC and BacT/Alert system were 74.13％ (149/201) and 74.63％ (150/201),respectively,compared with taking one set from each system.Conclusions BACTEC media has a shorter TTD and almost the same bacterial recovery,and lower false positive rate than the BacT/ Alert media.

Objective To elucidate the resistance mechanisms of clinical colistin-resistant Klebsiella pneumoniae and Escherichia coli isolates in China.Methods A total of 964 K.pneumoniae and 1 389 E. coli isolates were retrospectively collected from national surveillance programs from 2011 to 2014 in China. Antimicrobial susceptibility testing was determined by the microdilution method.The PCR amplification followed by sequencing was used to detect the mcr-1 gene and colistin-resistance genes, including mgrB, pmrB and phoQ.Real-time quantitative PCR was performed to examine the relative transcriptional levels of pmrB, pmrC, pmrD, pmrK and pmrE genes in K.pneumoniae, and pmrA, pmrB, pmrC, phoP and phoQ genes in E.coli.Conjugation experiment was used to detect the transferability of the resistance plasmid carrying the mcr-1 gene.Statistical analyses were performed using IBM SPSS Statistics (version 16.0) and a P value <0.05 was considered statistically significant. Results The colistin-resistant rates of K. pneumoniae and E.coli were 0.62% ( 6/964 ) and 1.66% ( 23/1 389 ) , respectively.No amino acids substitutions were identified in mgrB genes among colistin-resistant isolates.Among six colistin-resistant K. pneumoniae isolates, five isolates were identified to have point mutations in pmrB gene, but no point substitution was detected in phoQ gene.One to four point mutations had been found in pmrB and phoQ genes in colistin-resistant E.coli isolates, respectively.The expression level of pmrB, pmrC, pmrD, pmrK and pmrE genes showed no significant difference between colistin-resistant and colistin-susceptible isolates [pmrB, (1.04 ±1.12) vs.(0.94 ±0.67), P=0.945; pmrC, (1.39 ±2.01) vs.(0.16 ±0.27), P=0.101;pmrD, (1.59 ±2.43) vs.(0.88 ±0.34),P=0.445;pmrK, (0.64 ±0.62) vs.(0.04 ±0.10), P=0.051;pmrE, (3 492 833 388.83 ±8 478 977 986.85) vs.(20 771 428.93 ±38 000 732.85), P=0.445].However, the transcriptional level of pmrB genes in colistin-resistant group was 9.5-fold higher than that of the colistin-susceptible group in E.coli isolates.Four in six colistin-resistant K.pneumoniae isolates possessed mcr-1 gene, whereas all of the colistin-resistant E. coli had the mcr-1 gene. The conjugation verified the transferability rate of the plasmid carrying mcr-1 gene was 5.78 ×10-6 , and the MIC value of colistin of the conjugant increased 21-fold than the recipient strain.Conclusions Plasmid-mediated mcr-1 gene was the major reason for colistin resistance in clinical isolates of K.pneumoniae and E.coli. Some other resistance mechanisms such as transcriptional up-regulated pmrB gene also involved in colistin resistance.

OBJECTIVEThis study investigated the expression of BNIP3 in salivary adenoid cystic carcinoma (SACC) and its correlations to the clinicopathological features and prognosis of patients with SACC. The role of BNIP3 in the progress of hypoxia-induced autophagy was elucidated.

METHODSThe expression levels of BNIP3, hypoxia inducible factor (HIF)-1α, and LC3 in 65 SACC cases were detected by immunohistochemical staining method, and the correlation between the expression of BNIP3 and the clinicopathological features in SACC was analyzed. In addition, the correlations of BNIP3 gene expression with HIF-1α and LC3 gene expression were analyzed. The survival rate of patients with SACC was evaluated by univa-riate survival analysis.

RESULTSBNIP3 was considerably expressed in SACC in all three histological patterns, and was positive in 41 cases (63.1%). BNIP3 gene expression was significantly correlated with histological grade (P=0.001) and HIF-1α gene expression (P=0.011). By contrast, BNIP3 gene expression was not significantly correlated with LC3 gene expression (P=
0.167). The overall survival rate of patients with negative BNIP3 expression was better than that of patients with positive BNIP3 expression (P<0.05).

CONCLUSIONSBNIP3 might play a vital role in the tumorigenesis of SACC and may be a new target for gene therapy.
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