Feasibility of laparoscopic/robot-assisted surgery for Borrmann type 4 gastric cancer: a comparison study with conventional open surgery.

BACKGROUND: Laparoscopic surgery for early gastric cancer is regarded as a standard of care because of robust evidences obtained by several phase-III trials. Furthermore, the efficacy of laparoscopic radical surgery for advanced gastric cancer has been also reported. Meanwhile, the feasibility of laparoscopic surgery for Bormann type 4 gastric cancer, special type with unfavorable prognosis, remains unclear since excluded from eligibility of these trials. METHODS: This study included 100 patients with type 4 gastric cancer who underwent laparoscopic/robot-assisted (minimally invasive surgery (MIS) group; n = 32) or open (Open group; n = 68) curative surgery between 2008 and 2021. After propensity score matching, 30 patients in each group were extracted for analysis. Clinical data, including surgical and midterm survival outcomes, were retrospectively compared between the two groups. RESULTS: Incidences of postoperative complication (≥ Clavien-Dindo grade III) were recorded in 23.3% in the MIS group and 13.3% in the Open group, but no statistical significance was demonstrated (P = 0.50). The 3-year overall survival rate in the MIS group was better than that in the Open group (80.2% vs. 53.5%, log-rank, P = 0.03). The trend of recurrence site was similar. Multivariate analysis showed that adjuvant chemotherapy was an independent favorable prognostic factor (hazard ratio, 0.33, 95% confidence interval 0.11-0.93) for overall survival. MIS was indicated as a favorable prognostic factor (hazard ratio, 0.39, 95% confidence interval 0.39-1.07), but without statistical difference. CONCLUSION: While multidisciplinary treatment is mainstay of treatment because of the poor prognosis of this disease, minimally invasive surgery may play an important role in treatment if appropriate patient selection is done. Further analyses with larger sample size are necessary to reach a final conclusion regarding oncological efficacy.

Automatic surgical phase recognition-based skill assessment in laparoscopic distal gastrectomy using multicenter videos.

BACKGROUND: Gastric surgery involves numerous surgical phases; however, its steps can be clearly defined. Deep learning-based surgical phase recognition can promote stylization of gastric surgery with applications in automatic surgical skill assessment. This study aimed to develop a deep learning-based surgical phase-recognition model using multicenter videos of laparoscopic distal gastrectomy, and examine the feasibility of automatic surgical skill assessment using the developed model. METHODS: Surgical videos from 20 hospitals were used. Laparoscopic distal gastrectomy was defined and annotated into nine phases and a deep learning-based image classification model was developed for phase recognition. We examined whether the developed model's output, including the number of frames in each phase and the adequacy of the surgical field development during the phase of supra-pancreatic lymphadenectomy, correlated with the manually assigned skill assessment score. RESULTS: The overall accuracy of phase recognition was 88.8%. Regarding surgical skill assessment based on the number of frames during the phases of lymphadenectomy of the left greater curvature and reconstruction, the number of frames in the high-score group were significantly less than those in the low-score group (829 vs. 1,152, P < 0.01; 1,208 vs. 1,586, P = 0.01, respectively). The output score of the adequacy of the surgical field development, which is the developed model's output, was significantly higher in the high-score group than that in the low-score group (0.975 vs. 0.970, P = 0.04). CONCLUSION: The developed model had high accuracy in phase-recognition tasks and has the potential for application in automatic surgical skill assessment systems.

Artificial Intelligence in Surgery and Its Potential for Gastric Cancer.

Artificial intelligence (AI) has made significant progress in recent years, and many medical fields are attempting to introduce AI technology into clinical practice. Currently, much research is being conducted to evaluate that AI can be incorporated into surgical procedures to make them safer and more efficient, subsequently to obtain better outcomes for patients. In this paper, we review basic AI research regarding surgery and discuss the potential for implementing AI technology in gastric cancer surgery. At present, research and development is focused on AI technologies that assist the surgeon's understandings and judgment during surgery, such as anatomical navigation. AI systems are also being developed to recognize in which the surgical phase is ongoing. Such a surgical phase recognition systems is considered for effective storage of surgical videos and education, in the future, for use in systems to objectively evaluate the skill of surgeons. At this time, it is not considered practical to let AI make intraoperative decisions or move forceps automatically from an ethical standpoint, too. At present, AI research on surgery has various limitations, and it is desirable to develop practical systems that will truly benefit clinical practice in the future.

Advantages of robotic gastrectomy for overweight patients with gastric cancer: a comparison study of robotic gastrectomy and conventional laparoscopic gastrectomy.

PURPOSE: A high body mass index (BMI) generally increases the risk of postoperative complications because of the intraperitoneal adipose tissue. Robotic gastrectomy (RG) decreases the surgical difficulty of conventional laparoscopic gastrectomy (LG) for these patients. We conducted the present study to identify the advantages of RG over LG for overweight patients. METHODS: We reviewed clinical data on patients who underwent either LG or RG at the National Cancer Center Hospital East between January, 2014 and May, 2022. RESULTS: The 1298 patients eligible patients were divided into a non-overweight cohort (n = 996) (LG, n = 818; RG, n = 178) and an overweight cohort (n = 302) (LG, n = 250; RG, n = 52) according to a BMI cut-off of 25 kg/m2. In the overweight cohort, the RG group had a lower incidence of grade ≥ III postoperative complications (0.0 vs. 8.8%, p = 0.01) and grade ≥ II postoperative complications (11.5 vs. 22.0%, p = 0.12) than the LG group. Multivariate analysis identified that RG was significantly associated with a lower incidence of grade ≥ II postoperative complications in the overweight cohort (odds ratio, 0.33; 95% confidence interval, 0.12-0.87; p = 0.02). CONCLUSIONS: RG may reduce the risk of postoperative complications, compared with conventional LG, in overweight patients.

Performance evaluation of whole genome metagenomics sequencing with the MinION nanopore sequencer: Microbial community analysis and antimicrobial resistance gene detection.

Recently, the human gut microbiota has been implicated in various diseases such as immunological and neuropsychiatric disorders, and comprehensive gut microbiota analysis by metagenomic analysis using next-generation sequencers has been attracting attention. In this study, we compared microbial communities of 16S rDNA metagenome sequencing (16S-meta) and whole genome metagenome sequencing (WG-meta) using the nanopore sequencer MinION and 16S-meta using the Illumina Miseq sequencer with simulated and fecal samples, and evaluated the ability of WG-meta to detect antimicrobial resistance genes. We used the commercial Microbial Community DNA Standard as the DNA standard and a simulated sample comprising 17 strains of 15 bacterial species. In the detection of antimicrobial resistance genes, we used a simulated sample and spiked fecal samples containing Escherichia coli carrying blaCTX-M-27, Klebsiella pneumoniae carrying blaOXA-48, and Staphylococcus aureus carrying mecA. WG-meta using MinION was superior to 16S-meta and could accurately analyze the microbial communities at the species level, but it underestimated or misidentified the Bacillus subtilis group, Cryptococcus neoformans, Shigella sonnei, and Campylobacter jejuni. WG-meta using MinION could analyze the microbial communities in 5 min, and antimicrobial resistance gene detection using WG-meta could be performed in >30 min in the simulated sample with fewer bacterial counts.

Learning curve for the surgical time of laparoscopic cholecystectomy performed by surgical trainees using the three-port method: how many cases are needed for stabilization?

BACKGROUND: The assessment of laparoscopic cholecystectomy (LC) skills using operating times has not been well reported. We examined the total and partial operating times for LC procedures performed by surgical trainees to determine the required number of surgeries until the surgical time stabilizes. METHODS: We reviewed the video records of 514 consecutive LCs using the three-port method, performed by 16 surgical trainees. The total and partial surgical times were calculated and correlated to the surgeons' experience. RESULTS: The median total surgical time for a trainee's first LC was 112 (range 71-226) minutes. It reduced rapidly after the first 20 LCs and plateaued to its minimum after approximately 60 cases. A statistically significant time decrease was observed between the first 10 (median, range 112, 46-252 min) and the next 50-59 cases (64, 34-198 min), but not between the 50-59 and the subsequent 100-109 cases (71, 33-127 min). The total times taken by trainees who had performed > 50 operations were not significantly different from those taken by instructors during the study period. Surgery for 125 patients with acute cholecystitis took a significantly longer time (median 99 vs. 74 min with non-acute cholecystitis); however, the abovementioned time reduction findings showed similar results regardless of the patient's acute inflammation status. The partial operating times around the cervical/cystic duct and gallbladder bed reduced uniformly between the first 10 and the following 50-59 cases. Although time variations in total and cervical/cystic duct operating times were not correlated to the surgical experience, time fluctuation of gallbladder bed procedures reduced after 60 cases. CONCLUSION: The time required to perform an LC was inversely correlated with the experience of surgical trainees and halved after the first 60 cases. The surgical experience required for LC time stabilization is approximately 60 cases.

Comparison of Microorganism Detection, Time to Positivity, and Time-Dependent Shift in Viable Bacterial Count from VersaTREK and BacT/ALERT 3D Blood Culture Systems.

Rapid positive blood culture reporting allows early and appropriate treatment of severe infections to improve patient prognosis. This study evaluated performance of the VersaTREK system with gas pressure detection and tornado stirring method and the conventional BacT/ALERT 3D system. Time to positivity (TTP) of simulated blood cultures without whole blood using 17 ATCC strains was faster with VersaTREK than BacT/ALERT 3D, averaging 6.3 h in aerobic bottles and 12.7 hours in anaerobic bottles. In simulated blood cultures with whole blood using 53 clinical isolates, on average, VersaTREK was faster in aerobic bottles by 6.5 h but slower in anaerobic bottles by 3.8 h. Fifty of 53 simulated blood cultures with whole blood (94%) showed fastest TTP with VersaTREK. TTP of VersaTREK for anaerobic bacteria Bacteroides fragilis and Clostridium perfringens, Helicobacter cinaedi, and Candida glabrata was fast, and viable bacteria numbers in bottles using the Miles and Misra method increased quickly.

Rapid Detection of Carbapenemase-producing Genes by Multiplex Real-Time PCR with Melting Curve Analysis using a BD MAX™ Open System.

Recently, the global spread of carbapenemase-producing Enterobacterales has become a concern, and rapid detection methods are required. We have developed a rapid and inexpensive multiplex real-time PCR with melting curve analysis using the BD MAX™ system and evaluated it. We used 31 carbapenemase-producing Gram-negative bacteria (blaIMP group, 12; blaGES group, 6; blaNDM group, 5; blaVIM group, 3; blaKPC group, 3; blaOXA-48-like group, 1 strain; and blaIMP group + blaGES, 1 strain), 10 AmpC-producing Gram-negative bacteria, and 10 ESBLproducing Gram-negative bacteria. A BD MAX™ open platform system was used. Carbapenemase-positive and carbapenemase-negative strains were correctly identified 30 of 31 (excluding a blaIMP group and blaGES group co-coding strain) and all 20 of 20 isolates, respectively. Melting temperature (Tm) values of the various genes were as follows: blaIMP group, 81.2±0.5°C; blaVIM group, 91.8±0.4°C; blaNDM group, 85.4±0.3°C; blaGES group, 90.5±0.3°C; blaKPC group, 94.1±0.5°C; and blaOXA-48-like group, 82.1°C. Identification of the various genotypes was possible from the Tm values. However, only a peak derived from the blaGES group could be detected in the strains producing both blaIMP group and blaGES group simultaneously, suggesting that only the genotype with the highest expression level could be captured in cases of simultaneous production. In the carbapenemase-negative strains, no obvious peaks were observed in the 20 AmpC and 20 ESBL-producing Gram-negative bacteria, and even when Tm values were detected, the dF/dT values were low and easily differentiated. This method appears to be very useful as a rapid and inexpensive test that can provide detection in about 2 hours.

The Significance of Staging Laparoscopy in Detection of Radiologically Occult Peritoneal Carcinomatosis in Gastric Cancer With Gastric Outlet Obstruction: Consideration of The Optimal Treatment Approach.

BACKGROUND/AIM: Gastric cancer with gastric outlet obstruction (GOO) is generally found at an advanced stage and with an unfavorable prognosis. This study was performed to examine the prevalence of radiologically occult peritoneal carcinomatosis in GOO and determine the optimal treatment strategy. PATIENTS AND METHODS: This single-center study was a retrospective review of the clinical data of 186 patients with locally advanced gastric cancer at the distal stomach who underwent surgery from 2008 to 2016. These patients were divided into two groups according to the presence or absence of GOO due to cancer progression: With GOO (n=71) and without GOO (n=115). RESULTS: The incidence of peritoneal carcinomatosis [with macroscopic peritoneal deposits (P1)/positive peritoneal cytology (CY1)] detected at laparotomy/laparoscopy was significantly higher in the group with GOO than in the group without (32.4% vs. 9.6%, p<0.01). The R0 resection rate was lower in the group with GOO (62.0% vs. 87.0%, p<0.01). The 5-year overall survival rate was also lower in the group with GOO (43.9% vs. 68.5%, p<0.01). However, in the subset of patients who underwent R0 surgery, the 5-year rates were similar for the two groups (67.4% vs. 73.1%, p=0.91). The multivariable analysis showed that a type 3 tumor appearance (odds ratio=3.66) and presence of GOO (odds ratio=2.87) were predictors of peritoneal carcinomatosis. CONCLUSION: The prevalence of radiologically occult peritoneal carcinomatosis in gastric cancer with GOO exceeded 30%. Staging laparoscopy (gastrojejunal bypass, if needed) should be performed to determine the optimal treatment plan.

Evaluation of the VITEK2 AST-XN17 card for the detection of carbapenemase-producing Enterobacterales in isolates primarily producing metallo ß-lactamase.

Carbapenemase-producing Enterobacterales (CPE) are not always resistant to carbapenem antimicrobial susceptibility testing (AST) and can be difficult to detect. With the newly created VITEK2 AST-XN17 card, the types of antibiotics measured in AST can be increased. In this study, we evaluated the detectability of CPE using the results of AST with multiple antimicrobial agents with additional measurements of the AST-XN17 card. In addition, we evaluated the CPE detectability of comments on CPE using the VITEK2 Advance Expert System (AES). In total, 169 Enterobacterales samples, including 76 non-CPE and 93 CPE, collected from multiple medical institutions in the Kinki region of Japan, were used in this investigation. AST with VITEK2 was performed by adding the AST-XN17 card in addition to the AST-N268 or AST-N404 card. Measurement results were identified using cutoff values, primarily Clinical and Laboratory Standards Institute breakpoints, and the CPE detection capability of each antibiotic was evaluated in several terms, including sensitivity and specificity. The drugs highly sensitive to CPE detection were faropenem (FRPM) > 2 µg/mL at 100% and meropenem > 0.25 µg/mL at 98.9%; the highest specificity to CPE detection was for avibactam/ceftazidime (AVI/CAZ) > 8 µg/mL at 100%. The sensitivity and specificity of each card in the AES output were 86.2% and 94.7% for AST-N404 and AST-XN17 and 91.5% and 90.8% for AST-N268 and AST-XN17, respectively. AST using the VITEK2 AST-XN17 card is a useful test method of screening for CPE.

Comparison of surgical smoke between open surgery and laparoscopic surgery for colorectal disease in the COVID-19 era.

BACKGROUND: Surgical smoke during operation is a well-known health hazard for medical staff. This study aimed to investigate the dynamics of surgical smoke during open surgery or laparoscopic surgery for colorectal disease. METHODS: This study quantitated particulate matter (PM) counts as part of surgical smoke in 31 consecutive patients who underwent colectomy at the Niigata City General Hospital using a laser particle counter. Particles were graded by size as ≤ 2.5 µm PM (PM2.5) or > 2.5 µm PM (large PM). Operative procedures were categorized as either open surgery (n = 14) or laparoscopic surgery (n = 17). RESULTS: The median patient age was 72 (range 41-89) years and 58.1% were male. The total PM2.5, PM2.5 per hour, and maximum PM2.5 per minute counts during operation were significantly higher in open surgery than in laparoscopic surgery (P = 0.001, P < 0.001, and P = 0.029, respectively). Large PM counts (total, per hour, and maximum per minute) were also higher in the open surgery group than in the laparoscopic surgery group. The maximum PM2.5 concentration recorded was 38.6 µm/m3, which is considered "unhealthy for sensitive groups" according to the U.S. Environment Protection Agency air quality index standards, if it was a 24-h period mean value. CONCLUSION: Exposure to surgical smoke is lower during laparoscopic surgery than during open surgery for colorectal diseases.

Comparison of the oncological outcomes of stenting as a bridge to surgery and surgery alone in stages II to III obstructive colorectal cancer: a retrospective study.

PURPOSE: We evaluated the oncological outcomes of bridge to surgery (BTS) using stent compared with surgery alone for obstructive colorectal cancer. METHODS: Consecutive patients who underwent curative resection for stages II to III obstructive colorectal cancer at our institution from January 2009 to March 2020, were registered retrospectively and divided into 43 patients in the BTS group and 65 patients in the surgery alone group. We compared the surgical and oncological outcomes between the 2 groups. RESULTS: Stent-related perforation did not occur. One patient in whom the stent placement was unsuccessful underwent emergency surgery with poor decompression (clinical success rate, 97.7%). The pathological characteristics were not significantly different between the groups. The following surgical outcomes in the BTS group were superior to those in the surgery alone group; nonemergency surgery (P<0.001), surgical approach (P=0.006), and length of hospital stay (P=0.020). The median follow-up time was 44.9 months (range, 1.1-126.5 months). The 3-year relapse-free survival rates were 68.4% and 58.2% (P=0.411), and the overall survival rates were 78.3% and 88.2% (P=0.255) in the surgery alone and BTS groups, respectively. The 3-year locoregional recurrence rates were 10.2% and 8.0% (P=0.948), and distant metastatic recurrence rates were 13.3% and 30.4% (P=0.035) in the surgery alone and BTS groups, respectively. CONCLUSION: This study revealed that BTS with stent may be associated with a higher frequency of distant metastatic recurrence. Stent for stages II to III obstructive colorectal cancer potentially worsens oncological outcomes.

Is radiological psoas muscle area measurement a predictor of postoperative complications after rectal resection for rectal cancer? A retrospective study.

PURPOSE: Previous studies have reported that sarcopenia increases the risk of postoperative complications following colorectal resection. This retrospective study assessed the postoperative complications of rectal resection associated with sarcopenia. METHODS: We retrospectively analyzed 262 patients who underwent curative low anterior resection for primary rectal cancer from January 2008 to May 2020 at our institution. The patients were divided into a sarcopenia group (normalized total psoas muscle area < 6.36 cm2/m2 in males and < 3.92 cm2/m2 in females; N = 49) and a non-sarcopenia group (N = 213). RESULTS: The overall rate of postoperative complications within 30 days of surgery was higher in the sarcopenia group than in the non-sarcopenia group (46.9 vs. 29.6%; P = 0.028). The rate of postoperative remote infections was higher in the sarcopenia group than in the non-sarcopenia group (12.2 vs. 2.8%; P = 0.012). Sarcopenia was found to be a predictor of remote infection by a multivariate analysis (odds ratio, 4.08; 95% confidence interval, 1.12-14.80; P = 0.033). CONCLUSION: Sarcopenia diagnosed using the psoas muscle index was found to be an independent predictive factor for postoperative remote infection after curative low anterior resection for rectal cancer.

A case of pyogenic spondylitis caused by Paludibacteriumpurpuratum.

Paludibacterium purpuratum was first reported as a Gram stain-negative, curved, rod-shaped bacterium isolated from a wetland soil in 2016. We report the first case in the world, to our knowledge, of pyogenic spondylitis caused by P. purpuratum. The patient, a 78-year-old man, came to our hospital complaining chiefly of fever and pain in the left knee. He did not complain of low back pain at the time of examination, although increased low back pain was observed for the first time after admission. Magnetic resonance imaging of the lumbar spine and percutaneous needle biopsy at the L2/L3 disc level were performed, and pyogenic spondylitis was diagnosed. A curved, Gram stain-negative rod was detected in the blood culture obtained at admission that was identified as P. purpuratum by 16S rDNA gene analysis.

Genomic Characterization of ESBL- and Carbapenemase-Positive Enterobacteriaceae Co-harboring mcr-9 in Japan.

Worldwide spread of Enterobacteriaceae resistant to colistin, a polypeptide antibacterial drug for last-resort treatment of carbapenemase-producing Enterobacteriaceae (CPE) infections, is concerning. This study aimed to elucidate colistin MICs and molecular characteristics of mcr-1 to mcr-9 of ESBL-producing Escherichia coli (ESBL-Ec) and CPE in Japan and clarify the genomic structure of strains harboring mcr genes (especially mcr-9). This study included 168 ESBL-Ec and 126 CPE strains isolated at Japanese medical facilities. Colistin susceptibility testing and multiplex PCR targeting mcr-1 to mcr-9 were performed for all strains with S1-nuclease pulsed-field gel electrophoresis, Southern blot hybridization, and whole-genome sequencing (WGS) with hybrid assembly performed for mcr gene-carrying strains. Two CPE strains showed a MIC ≥ 4 µg/ml in colistin susceptibility testing, with no known resistance mechanism detected. However, PCR conducted on all target strains detected three mcr-9-carrying strains showing colistin susceptibility. The bla CTX-M-62 -positive E. coli THUN648 strain simultaneously carried bla CTX-M-62 and mcr-9 on a 275-kbp plasmid. Besides, bla IMP-6 + bla CTX-M-2 -positive Klebsiella pneumoniae THUN262 and bla GES-24 -positive Enterobacter kobei THUN627 had mcr-9 encoded on the chromosome. Only THUN627 encoded qseB/C, which is suggested to be a regulatory gene for mcr-9, downstream of mcr-9. However, this strain showed no increased expression of these genes in mRNA quantitative analysis under colistin exposure. Colistin MICs of ESBL-Ec and CPE in Japan were all below 2 µg/ml, which is below the epidemiological cutoff (ECOFF) value (https://eucast.org/) or clinical breakpoint (CB) (CLSI M100-S30) reported for colistin, indicating neither "microbiological" nor "clinical" resistance. Several colistin-susceptible Enterobacteriaceae carrying silent mcr-9 encoded on plasmids and chromosomes have already spread worldwide along with other antimicrobial resistance genes. However, the mechanism of colistin resistance by mcr-9 remains unclear.

Nosocomial infections caused by vancomycin-resistant Enterococcus in a Japanese general hospital and molecular genetic analysis.

INTRODUCTION: Vancomycin-resistant Enterococcus (VRE) is a rare bacterium in Japan, but an outbreak due to nosocomial transmission in medical facilities has been reported in recent years. Here, we report the outbreak of vanA vancomycin-resistant Enterococcus faecium (VREfm) in multiple wards of Nara Prefectural General Medical Center in 2019 and results of the molecular epidemiology analysis. METHODS: An aggressive screening program was conducted after the first VREfm was detected in a patient in the A ward. During the outbreak, 6000 rectal swab samples were screened for VRE by culture. Isolates from 60 patients with VREfm detected were clustered using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS: PFGE revealed a cluster consisting of three major clusters and four multi-strains. The first major cluster consisted of 26 isolates, the second consisted of 10 isolates, the third consisted of 6 isolates, and the remaining 4 clusters consisted of 2 isolates. MLST identified an allele profile (ST80) in most clusters of clone types P01-P06 but an allele profile (ST992) in cluster P07. CONCLUSION: Based on the PFGE pattern, this case was considered to be a nosocomial infection due to multiple clones. Later, in addition to screening, sharing of hospital information, cohorting of patients and staff, and strengthening of environmental cleanup were carried out, and horizontal infection was suppressed.

A rare case of nivolumab-related myasthenia gravis and myocarditis in a patient with metastatic gastric cancer.

BACKGROUND: Although rare, several immune-related adverse effects can be life-threatening. Here, we describe a metastatic gastric cancer patient presenting with nivolumab-related myasthenia gravis and myocarditis, a previously unreported adverse effect of gastric cancer treatment. CASE PRESENTATION: A 66-year-old man with metastatic gastric cancer visited the emergency department because of dizziness after the first dose of nivolumab. Diagnoses of nivolumab-related myasthenia gravis and myocarditis were established. Myocardial biopsy results and anti-acetylcholine receptor antibody positivity confirmed the diagnoses. Despite plasma exchange and intravenous methylprednisolone and immunoglobulin administration, the patient's general condition gradually worsened, and he died. CONCLUSIONS: Strict monitoring for cardiac and neuromuscular symptoms after nivolumab administration is necessary to rapidly treat these adverse effects.

Comparison of the performance of three carbapenem inactivation methods for the detection of carbapenemase-producing gram-negative bacilli.

INTRODUCTION: The carbapenem inactivation method test (CIM) was developed as a method for detecting carbapenemase-producing Gram-negative bacilli, and the modified CIM (mCIM) was recommended by the CLSI for as an improved method in M100-S27. However, few studies have evaluated the influence of bacterial species and genotype on its sensitivity and specificity. In this study, we evaluate the performance of these improved modified CIM methods with mCIM. METHODS: As strains, clinical isolates from Naga Municipal Hospital and stored strains from the Study of Bacterial Resistance in the Kinki Region of Japan were used. The mCIM, CIM-Tris, and simple CIM (sCIM) test methods were applied to 120 Enterobacterales, 40 Pseudomonas aeruginosa, and 37 Acinetobacter spp. The procedure and criteria for each method were based on the original papers and the CLSI M - 100 S27 documents. RESULTS: The sensitivity of the test methods in the detection of carbapenemase in Enterobacterales, Pseudomonas spp., and Acinetobacter spp. was as follows: mCIM, 98.9%, 90.0%, and 76.5%, respectively; CIM-Tris, 94.4%, 100%, 100%; and sCIM 98.9%, 85.0%, 76.5%. All methods showed 100% specificity in Enterobacterales, Pseudomonas spp., and Acinetobacter spp. Each method performed well in the detection of metallo ß-lactamase-producing strains, however, the sensitivity tended to be low in the detection of the organisms producing serine-type carbapenemase, such as GES, OXA-23, and OXA-51. CONCLUSIONS: Care must be taken when selecting test methods because the sensitivity of the detection differs depending on the bacterial species and genotype.

Evaluation of five Legionella urinary antigen detection kits including new Ribotest Legionella for simultaneous detection of ribosomal protein L7/L12.

Urinary antigen tests are a widely used rapid diagnostic method for Legionella pneumonia. However, conventional urinary antigen tests are unable to detect anything other than Legionella pneumophila serogroup 1. The Ribotest Legionella (Ribotest) can detect all serogroups by using antibodies recognizing L. pneumophila ribosomal protein L7/L12 in addition to the conventional L. pneumophila serogroup 1 lipopolysaccharide. The aim of this study was to evaluate the performance of Ribotest against conventional urinary antigen tests, including the detection of Legionellaceae other than L. pneumophila. We investigated the detection sensitivity of various kits using in-vitro culture-soluble antigen extracts of ATCC strains and 22 clinical isolates collected from multiple medical facilities in the Kinki region of Japan. For L. pneumophila serogroup 1, four kits, including Ribotest, had a detection sensitivity of 105 CFU/mL, with only Check Legionella having a sensitivity of 106 CFU/mL. L. pneumophila non-serogroup 1 and Legionellaceae of other species were undetectable by the four conventional kits, whereas Ribotest could detect them with a sensitivity of 105-108 CFU/mL. The Ribotest was also able to detect other species such as Legionella hackeliae, Legionella feeleii, Legionella anisa, Fluoribacter bozemanae, and Fluoribacter dumoffii, but the detection sensitivity of L. hackeliae and L. feeleii was 108 CFU/mL, which was much lower than that of the other strains. The Ribotest has high potential to be applied as a rapid diagnostic method for pneumonia caused by other species of Legionella and Fluoribacter.

Novel strategy of rapid typing of Shiga toxin-producing Escherichia coli using MALDI Biotyper and ClinProTools analysis.

INTRODUCTION: Rapid detection of Shiga toxin-producing Escherichia coli (STEC) is essential. Matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid, accurate, and low-cost microbial identification. We aimed to examine the discrimination ability of MALDI Biotyper (Bruker Daltonics) between STEC and non-STEC. METHODS: In total, 234 strains (79 STEC strains and 155 non-STEC strains) isolated from stool between 2009 and 2014 were measured by MALDI Biotyper and mass spectra of 2000-20,000 m/z were analyzed with ClinProTools (Bruker Daltonics). Eighty-three strains were randomly extracted to produce STEC detection models using 3 algorithms, and 151 strains were used as validation samples to verify STEC detection performance and discrimination performance of Shiga toxins with the STEC detection models. RESULTS: The STEC detection model with Quick Classifier (QC) algorithm was the most sensitive: sensitivity, 84.1% (37/44); specificity, 94.4% (101/107). Discrimination between STEC and non-STEC was excellent, but individual discrimination of Shiga toxins was not possible. CONCLUSION: MALDI Biotyper may be a useful rapid diagnostic method for STEC infection.