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Introduction: The variety of robotic surgery systems, training modalities, and assessment tools within robotic surgery training is extensive. This systematic review aimed to comprehensively overview different training modalities and assessment methods for teaching and assessing surgical skills in robotic surgery, with a specific focus on comparing objective and subjective assessment methods. Methods: A systematic review was conducted following the PRISMA guidelines. The electronic databases Pubmed, EMBASE, and Cochrane were searched from inception until February 1, 2022. Included studies consisted of robotic-assisted surgery training (e.g., box training, virtual reality training, cadaver training and animal tissue training) with an assessment method (objective or subjective), such as assessment forms, virtual reality scores, peer-to-peer feedback or time recording. Results: The search identified 1591 studies. After abstract screening and full-texts examination, 209 studies were identified that focused on robotic surgery training and included an assessment tool. The majority of the studies utilized the da Vinci Surgical System, with dry lab training being the most common approach, followed by the da Vinci Surgical Skills Simulator. The most frequently used assessment methods included simulator scoring system (e.g., dVSS score), and assessment forms (e.g., GEARS and OSATS). Conclusion: This systematic review provides an overview of training modalities and assessment methods in robotic-assisted surgery. Dry lab training on the da Vinci Surgical System and training on the da Vinci Skills Simulator are the predominant approaches. However, focused training on tissue handling, manipulation, and force interaction is lacking, despite the absence of haptic feedback. Future research should focus on developing universal objective assessment and feedback methods to address these limitations as the field continues to evolve.

Background: Artificial intelligence (AI) models have been applied in various medical imaging modalities and surgical disciplines, however the current status and progress of ultrasound-based AI models within hepatopancreatobiliary surgery have not been evaluated in literature. Therefore, this review aimed to provide an overview of ultrasound-based AI models used for hepatopancreatobiliary surgery, evaluating current advancements, validation, and predictive accuracies. Method: Databases PubMed, EMBASE, Cochrane, and Web of Science were searched for studies using AI models on ultrasound for patients undergoing hepatopancreatobiliary surgery. To be eligible for inclusion, studies needed to apply AI methods on ultrasound imaging for patients undergoing hepatopancreatobiliary surgery. The Probast risk of bias tool was used to evaluate the methodological quality of AI methods. Results: AI models have been primarily used within hepatopancreatobiliary surgery, to predict tumor recurrence, differentiate between tumoral tissues, and identify lesions during ultrasound imaging. Most studies have combined radiomics with convolutional neural networks, with AUCs up to 0.98. Conclusion: Ultrasound-based AI models have demonstrated promising accuracies in predicting early tumoral recurrence and even differentiating between tumoral tissue types during and after hepatopancreatobiliary surgery. However, prospective studies are required to evaluate if these results will remain consistent and externally valid. Graphical abstract:

Introduction: Robot-assisted surgery is often performed by experienced laparoscopic surgeons. However, this technique requires a different set of technical skills and surgeons are expected to alternate between these approaches. The aim of this study is to investigate the crossover effects when switching between laparoscopic and robot-assisted surgery. Methods: An international multicentre crossover study was conducted. Trainees with distinctly different levels of experience were divided into three groups (novice, intermediate, expert). Each trainee performed six trials of a standardized suturing task using a laparoscopic box trainer and six trials using the da Vinci surgical robot. Both systems were equipped with the ForceSense system, measuring five force-based parameters for objective assessment of tissue handling skills. Statistical comparison was done between the sixth and seventh trial to identify transition effects. Unexpected changes in parameter outcomes after the seventh trial were further investigated. Results: A total of 720 trials, performed by 60 participants, were analysed. The expert group increased their tissue handling forces with 46% (maximum impulse 11.5 N/s to 16.8 N/s, p= 0.05), when switching from robot-assisted surgery to laparoscopy. When switching from laparoscopy to robot-assisted surgery, intermediates and experts significantly decreased in motion efficiency (time (sec), resp. 68 vs. 100, p= 0.05, and 44 vs. 84, p= 0.05). Further investigation between the seventh and ninth trial showed that the intermediate group increased their force exertion with 78% (5.1 N vs. 9.1 N, p= 0.04), when switching to robot-assisted surgery. Conclusion: The crossover effects in technical skills between laparoscopic and robot-assisted surgery are highly depended on the prior experience with laparoscopic surgery. Where experts can alternate between approaches without impairment of technical skills, novices and intermediates should be aware of decay in efficiency of movement and tissue handling skills that could impact patient safety. Therefore, additional simulation training is advised to prevent from undesired events.

IMPORTANCE: Laparoscopic gastrectomy is rapidly being adopted worldwide as an alternative to open gastrectomy to treat gastric cancer. However, laparoscopic gastrectomy might be more expensive as a result of longer operating times and more expensive surgical materials. To date, the cost-effectiveness of both procedures has not been prospectively evaluated in a randomized clinical trial. OBJECTIVE: To evaluate the cost-effectiveness of laparoscopic compared with open gastrectomy. DESIGN, SETTING, AND PARTICIPANTS: In this multicenter randomized clinical trial of patients undergoing total or distal gastrectomy in 10 Dutch tertiary referral centers, cost-effectiveness data were collected alongside a multicenter randomized clinical trial on laparoscopic vs open gastrectomy for resectable gastric adenocarcinoma (cT1-4aN0-3bM0). A modified societal perspective and 1-year time horizon were used. Costs were calculated on the individual patient level by using hospital registry data and medical consumption and productivity loss questionnaires. The unit costs of laparoscopic and open gastrectomy were calculated bottom-up. Quality-adjusted life-years (QALYs) were calculated with the EuroQol 5-dimension questionnaire, in which a value of 0 indicates death and 1 indicates perfect health. Missing questionnaire data were imputed with multiple imputation. Bootstrapping was performed to estimate the uncertainty surrounding the cost-effectiveness. The study was conducted from March 17, 2015, to August 20, 2018. Data analyses were performed between September 1, 2020, and November 17, 2021. INTERVENTIONS: Laparoscopic vs open gastrectomy. MAIN OUTCOMES AND MEASURES: Evaluations in this cost-effectiveness analysis included total costs and QALYs. RESULTS: Between 2015 and 2018, 227 patients were included. Mean (SD) age was 67.5 (11.7) years, and 140 were male (61.7%). Unit costs for initial surgery were calculated to be €8124 (US $8087) for laparoscopic total gastrectomy, €7353 (US $7320) for laparoscopic distal gastrectomy, €6584 (US $6554) for open total gastrectomy, and €5893 (US $5866) for open distal gastrectomy. Mean total costs after 1-year follow-up were €26 084 (US $25 965) in the laparoscopic group and €25 332 (US $25 216) in the open group (difference, €752 [US $749; 3.0%]). Mean (SD) QALY contributions during 1 year were 0.665 (0.298) in the laparoscopic group and 0.686 (0.288) in the open group (difference, −0.021). Bootstrapping showed that these differences between treatment groups were relatively small compared with the uncertainty of the analysis. CONCLUSIONS AND RELEVANCE: Although the laparoscopic gastrectomy itself was more expensive, after 1-year follow-up, results suggest that differences in both total costs and effectiveness were limited between laparoscopic and open gastrectomy. These results support centers’ choosing, based on their own preference, whether to (de)implement laparoscopic gastrectomy as an alternative to open gastrectomy.

Background: Adequate lymphadenectomy is an important step in gastrectomy for cancer, with a modified D2 lymphadenectomy being recommended for advanced gastric cancers. When assessing a novel technique for the treatment of gastric cancer, lymphadenectomy should be non-inferior. The aim of this study was to assess completeness of lymphadenectomy and distribution patterns between open total gastrectomy (OTG) and minimally invasive total gastrectomy (MITG) in the era of peri-operative chemotherapy. Methods: This is a retrospective analysis of the STOMACH trial, a randomized clinical trial in thirteen hospitals in Europe. Patients were randomized between OTG and MITG for advanced gastric cancer after neoadjuvant chemotherapy. Three-year survival, number of resected lymph nodes, completeness of lymphadenectomy, and distribution patterns were examined. Results: A total of 96 patients were included in this trial and randomized between OTG (49 patients) and MITG (47 patients). No difference in 3-year survival was observed, this was 57.1% in OTG group versus 46.8% in MITG group (P= 0.186). The mean number of examined lymph nodes per patient was 44.3 ± 16.7 in the OTG group and 40.7 ± 16.3 in the MITG group (P= 0.209). D2 lymphadenectomy of 71.4% in the OTG group and 74.5% in the MITG group was performed according to the surgeons; according to the pathologist compliance to D2 lymphadenectomy was 30% in the OTG group and 36% in the MITG group. Tier 2 lymph node metastases (stations 7–12) were observed in 19.6% in the OTG group versus 43.5% in the MITG group (P= 0.024). Conclusion: No difference in 3-year survival was observed between open and minimally invasive gastrectomy. No differences were observed for lymph node yield and type of lymphadenectomy. Adherence to D2 lymphadenectomy reported by the pathologist was markedly low.

Background: Machine learning (ML) has seen an increase in application, and is an important element of a digital evolution. The role of ML within upper gastrointestinal surgery for malignancies has not been evaluated properly in the literature. Therefore, this systematic review aims to provide a comprehensive overview of ML applications within upper gastrointestinal surgery for malignancies. Methods: A systematic search was performed in PubMed, EMBASE, Cochrane, and Web of Science. Studies were only included when they described machine learning in upper gastrointestinal surgery for malignancies. The Cochrane risk-of-bias tool was used to determine the methodological quality of studies. The accuracy and area under the curve were evaluated, representing the predictive performances of ML models. Results: From a total of 1821 articles, 27 studies met the inclusion criteria. Most studies received a moderate risk-of-bias score. The majority of these studies focused on neural networks (n= 9), multiple machine learning (n= 8), and random forests (n= 3). Remaining studies involved radiomics (n= 3), support vector machines (n= 3), and decision trees (n= 1). Purposes of ML included predominantly prediction of metastasis, detection of risk factors, prediction of survival, and prediction of postoperative complications. Other purposes were predictions of TNM staging, chemotherapy response, tumor resectability, and optimal therapy. Conclusions: Machine Learning algorithms seem to contribute to the prediction of postoperative complications and the course of disease after upper gastrointestinal surgery for malignancies. However, due to the retrospective character of ML studies, these results require trials or prospective studies to validate this application of ML. Graphical abstract:

Chiral hydroxy- and aminohydroxysulfonic acids are widespread in the marine and terrestrial environment. Here we report simple methods for the synthesis of d- and l-cysteinolic acid (from (Boc-d-Cys-OH)2and (Boc-l-Cys-OH)2, respectively), R- and S-3-amino-2-hydroxypropanesulfonate (from S- and R-epichlorohydrin, respectively), and R- and S-2,3-dihydroxypropanesulfonate (from S- and R-epichlorohydrin, respectively). d-Cysteinolate bile salts were generated by coupling with cholic and chenodeoxycholic acids. A series of single-crystal 3D X-ray structures confirmed the absolute configurations of the aminosulfonates. By comparison of optical rotation, we assign naturally occurring 3-amino-2-hydroxypropanesulfonate from Gateloupia lividaas possessing the R-configuration. This simple synthetic approach will support future studies of the occurrence, chemotaxonomic distribution, and metabolism of these alkylsulfonates.

BACKGROUND: Transthoracic minimally invasive esophagectomy (MIE) is increasingly performed as part of curative multimodality treatment. There appears to be no robust evidence on the preferred location of the anastomosis after transthoracic MIE. OBJECTIVE: To compare an intrathoracic with a cervical anastomosis in a randomized clinical trial. DESIGN, SETTING, AND PARTICIPANTS: This open, multicenter randomized clinical superiority trial was performed at 9 Dutch high-volume hospitals. Patients with midesophageal to distal esophageal or gastroesophageal junction cancer planned for curative resection were included. Data collection occurred from April 2016 through February 2020. INTERVENTION: Patients were randomly assigned (1:1) to transthoracic MIE with intrathoracic or cervical anastomosis. MAIN OUTCOMES AND MEASURES: The primary end point was anastomotic leakage requiring endoscopic, radiologic, or surgical intervention. Secondary outcomes were overall anastomotic leak rate, other postoperative complications, length of stay, mortality, and quality of life. RESULTS: Two hundred sixty-two patients were randomized, and 245 were eligible for analysis. Anastomotic leakage necessitating reintervention occurred in 15 of 122 patients with intrathoracic anastomosis (12.3%) and in 39 of 123 patients with cervical anastomosis (31.7%; risk difference, −19.4% [95% CI, −29.5% to −9.3%]). Overall anastomotic leak rate was 12.3% in the intrathoracic anastomosis group and 34.1% in the cervical anastomosis group (risk difference, −21.9% [95% CI, −32.1% to −11.6%]). Intensive care unit length of stay, mortality rates, and overall quality of life were comparable between groups, but intrathoracic anastomosis was associated with fewer severe complications (risk difference, −11.3% [−20.4% to −2.2%]), lower incidence of recurrent laryngeal nerve palsy (risk difference, −7.3% [95% CI, −12.1% to −2.5%]), and better quality of life in 3 subdomains (mean differences: dysphagia, −12.2 [95% CI, −19.6 to −4.7]; problems of choking when swallowing, −10.3 [95% CI, −16.4 to 4.2]; trouble with talking, −15.3 [95% CI, −22.9 to −7.7]). CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, intrathoracic anastomosis resulted in better outcome for patients treated with transthoracic MIE for midesophageal to distal esophageal or gastroesophageal junction cancer. TRIAL REGISTRATION: Trialregister.nl Identifier: NL4183 (NTR4333)

The LIR!C trial showed that laparoscopic ileocaecal resection is a cost-effective treatment that has similar quality-of-life outcomes to treatment with infliximab, an anti-tumour necrosis factor (TNF) drug. We aimed to compare long-term outcomes of both interventions and identify baseline factors associated with the duration of treatment effect in each group.

Incretins, bile acids and the gut microbiome are involved in the pathophysiology of obesity and type 2 diabetes. The incretins glucagon-like peptide-1 and glucose-dependent-insulinetrophic polypeptide, both influence beta-cell function, insulin and glucose sensitivity, and food intake. Studies have shown that concentrations of both incretins change after bariatric surgery and nowadays glucagon-like peptide-1 agonists are administered as glucose and body weight regulating agents. Bile acids also play an important role in glycemic and metabolic regulation via multiple signaling pathways. After bariatric surgical interventions increase in bile acid concentrations have been observed combined with improvement of metabolic health. It is not clear though, whether this is a direct effect of the altered concentration of bile acids or an epiphenomenon. In addition, alterations in the microbiome are seen in patients with type 2 diabetes and people with obesity. The gut microbiome, probably together with incretins and bile acids, is essential in digestion and nutrient metabolism. After bariatric procedures several alterations in bacterial abundance have been demonstrated with specific bacterial species having different effects on glycemic and metabolic conditions

Mincle is a C-type lectin receptor of the innate immune system with the ability to sense pathogens and commensals through lipidic metabolites. While a growing number of bacterial glycolipids have been discovered that can signal through human Mincle, no fungal metabolites are known that can signal through the human form of this receptor. We report the total synthesis of a complex β-1,2-mannosyloxymannitol glycolipid from Malassezia pachydermatis44-2, which was reported to signal through the murine Mincle receptor. Assembly of 44-2was achieved through a highly convergent route that exploits symmetry elements inherent within this molecule and delineation of conditions that maintain the delicate l-mannitol triester-triol array. We show that 44-2is a potent agonist of human Mincle signaling and constitutes the first fungal metabolite identified that can signal through the human Mincle receptor, providing new insights into antifungal immunity.

Sulfoglycolysis is a metabolic pathway dedicated to the catabolism of the sulfosugar sulfoquinovose (SQ) into smaller organosulfur fragments. An estimated 10 billion tonnes of SQ fluxes through sulfoglycolysis pathways each year, making it a significant aspect of the biogeochemical sulfur cycle. Delineating the molecular details of sulfoglycolysis requires authentic samples of the various metabolites in these pathways. To this end, we have established chemical and chemoenzymatic methods for the synthesis of the key organosulfur metabolites sulfoquinovosylglycerol, SQ (also in 13C6-labeled form), sulfofructose, sulfofructose-1-phosphate, sulfolactaldehyde, and 2,3-dihydroxypropanesulfonate, as well as an improved route to the chromogenic sulfoquinovosidase substrate 4-nitrophenyl α-sulfoquinovoside.

Treatment of patients with ileocaecal Crohn's disease who have not responded to conventional therapy is commonly scaled up to biological agents, but surgery can also offer excellent short-term and long-term results. We compared laparoscopic ileocaecal resection with infliximab to assess how they affect health-related quality of life.

An experiment was conducted to determine the effects of diet composition, feeding level (FL), and BW on endogenous phosphorous losses (EPL) using growing-finishing (GF) pigs and sows. After an adaptation period, 48 GF pigs (initial BW 90.5 kg) and 48 just-weaned sows (initial BW 195 kg), both individually housed, were allotted to 12 dietary treatments in a 2 × 3 × 2 factorial arrangement. Treatments were animal type (GF pigs or sows), diet composition (a semipurified starch (STA), inulin (INU), or lignocellulose (CEL) based low-P diet), and FL (2.0 or 3.0 kg/d). Digestibility of DM, OM, CP, crude fat, and carbohydrates (COH), and fecal P excretion (in g/d, mg/kg DMI, and g/(kg BW·d)) were determined using TiO2as indigestible marker. Digestibility of OM and COH differed among diets (P< 0.001) and was greatest in both types of pigs fed the STA diet and lowest in those fed the CEL diet. While digestibility of OM and COH was similar in sows and GF pigs that were fed the STA diet and the CEL diet, on the INU diet, sows had, compared with GF pigs, a greater digestibility of OM (92.2 vs. 87.2%) and COH (92.5 vs. 88.4%), respectively. Both BW and FL increased fecal P excretion (g/d). When expressed in mg/kg DMI, P excretion was higher in sows than in GF pigs on the STA diet (498 versus 236 mg/kg DMI), the INU diet (526 vs. 316 mg/kg DMI), and the CEL diet (928 vs. 342 mg/kg DMI). When expressed in mg/(kg BW·d), however, P excretion was similar in GF pigs and sows that were fed the STA diet and in those that were fed the INU diet, whereas it was greater in sows than in GF pigs that were fed the CEL diet (11.6 vs. 7.3 mg/(kg BW·d)). The results of this study indicate that EPL (mg/kg DMI) in pigs substantially increase with increasing BW. Application of EPL (mg/kg DMI) determined in GF pigs may underestimate EPL and therefore P requirements in gestating sows. Moreover, EPL is diet dependent and increases with an increasing content of dietary nonstarch polysaccharides (NSP). The degree of this increase may differ between sows and GF pigs and seems to depend on properties of dietary fiber.

Since the first laparoscopic procedure, there has been an steady increase in advanced minimally invasive surgery. These procedures include oncological colorectal, hepatobiliary and upper gastrointestinal surgery. Implementation of these procedures requires different and new skills for the surgeons who wish to perform these procedures. To accomplish this surgical teaching program, a mentorship seems the most ideal method to teach the apprentice surgeon these specific skills.

Gastric cancer is responsible for 10 % of all cancer-related deaths worldwide. With improved operative techniques and neo-adjuvant therapy, survival rates are increasing. Outcomes of interest are shifting to quality of life (QOL), with many different tools available. The aim of this study was to assess which patient-reported outcome measures (PROMs) are used to measure QOL after a gastrectomy for cancer. A comprehensive search was conducted for original articles investigating QOL after gastrectomy. Two authors independently selected relevant articles, conducted clinical appraisal and extracted data (P.J. and J.S.). Out of 3414 articles, 26 studies were included, including a total of 4690 patients. These studies included ten different PROMs, which could be divided into generic, symptom-specific and disease-specific questionnaires. The EORTC and the FACT questionnaires use an oncological overall QOL module and an organ-specific module. Only one validation study regarding the use of the EORTC after surgery for gastric cancer was available, demonstrating good psychometric properties and clinical validity. A great variety of PROMs are being used in the measurement of QOL after surgery for gastric cancer. A questionnaire with a general module along with a disease-specific module for the assessment of QOL seems most desirable, such as the EORTC and the FACT with their specific modules. Both are developed in different treatment modalities, such as in surgical patients. EORTC is the most widely used questionnaire and therefore allows for comparison of new studies to existing data. Future studies are needed to assess content validity in surgical gastric cancer patients.

Due to centralization and super-specialization in medicine, hospital mergers are increasingly common. Their effect on postoperative outcomes in highly specialized surgical departments is unclear. As quality metrics often worsen after major organizational changes, preservation of quality of care during an hospital merge is of the utmost importance.

This study compared the development until 9 wk of age of piglets raised in either a multi-litter (ML) system or a conventional single-litter (SL) system. The ML system consisted of a multi-suckling system with 5 sows and their litters before weaning, followed by housing in a pen with enrichment in a group of 40 piglets after weaning. In the SL system, piglets were housed with a crated sow before weaning, followed by postweaning housing in groups of 10 littermates in a standard pen. Fifty litters were used in 5 batches and piglets were weaned at 4 wk of age. Preweaning mortality was higher in the ML system than in the SL system (3.22 ± 0.42 vs. 1.52 ± 0.25 piglets per litter, P< 0.01), mainly due to crushing before grouping of litters. Litter size at grouping did not differ between systems. ML piglets showed more feed-directed behavior at 2 wk of age (6.80 ± 0.96 vs. 2.35 ± 0.59, P< 0.01), suggesting an earlier start of feed exploration, possibly due to social learning from the floor-fed sows and other piglets. Moreover, before weaning, ML piglets showed less damaging oral manipulation (e.g., tail biting) than SL piglets (1.4 ± 0.2 vs. 3.6 ± 0.3 freq/h, P< 0.001), which was likely related to the more enriched environment in the ML system. After weaning, ML piglets ate 81% more feed between d 1 and 2 (0.29 ± 0.02 vs. 0.16 ± 0.03 kg/piglet, P< 0.01) and had an 82% higher weight gain until d 5 than SL piglets (1.35 ± 0.21 vs. 0.75 ± 0.17 kg, P< 0.05) despite a similar weaning weight (ML: 8.4 ± 0.2 kg, SL: 8.3 ± 0.2 kg). Within the first 2 wk after weaning, ML piglets had a lower fecal consistency score (0.27 ± 0.03 vs. 0.39 ± 0.03, P< 0.05), indicating a lower occurrence of diarrhea compared with SL piglets. Over the entire 5-wk postweaning phase, ML piglets had a 24% higher weight gain (P< 0.05) and showed more play behavior (4.0 ± 0.3 vs. 2.8 ± 0.3 freq/h, P< 0.05) and less damaging oral manipulation (1.8 ± 0.3 vs. 3.5 ± 0.4 freq/h, P< 0.01) than SL piglets. These results are probably explained by a combination of the differences in preweaning development, early postweaning performance, and postweaning environment, with a larger and more diverse social group and more physical enrichment in the ML pen. To summarize, provided that preweaning mortality can be reduced, the ML system seems promising for raising robust piglets with better welfare, indicated by a better preweaning behavioral development, improved transition to the postweaning phase, and better postweaning performance.

Case series suggest that laparoscopic peritoneal lavage might be a promising alternative to sigmoidectomy in patients with perforated diverticulitis. We aimed to assess the superiority of laparoscopic lavage compared with sigmoidectomy in patients with purulent perforated diverticulitis, with respect to overall long-term morbidity and mortality.

Pathogenic species of Mycobacteria and Corynebacteria, including Mycobacterium tuberculosisand Corynebacterium diphtheriae, synthesize complex cell walls that are rich in very long-chain mycolic acids. These fatty acids are synthesized on the inner leaflet of the cell membrane and are subsequently transported to the periplasmic space as trehalose monomycolates (TMM), where they are conjugated to other cell wall components and to TMM to form trehalose dimycolates (TDM). Mycobacterial TMM, and the equivalent Corynebacterium glutamicumtrehalose corynomycolates (TMCM), are transported across the inner membrane by MmpL3, or NCgl0228 and NCgl2769, respectively, although little is known about how this process is regulated. Here, we show that transient acetylation of the mycolyl moiety of TMCM is required for periplasmic export. A bioinformatic search identified a gene in a cell wall biosynthesis locus encoding a putative acetyltransferase (M. tuberculosisRv0228/C. glutamicumNCgl2759) that was highly conserved in all sequenced Corynebacterineae. Deletion of C. glutamicumNCgl2759resulted in the accumulation of TMCM, with a concomitant reduction in surface transport of this glycolipid and syntheses of cell wall trehalose dicorynomycolates. Strikingly, loss of NCgl2759 was associated with a defect in the synthesis of a minor, and previously uncharacterized, glycolipid species. This lipid was identified as trehalose monoacetylcorynomycolate (AcTMCM) by mass spectrometry and chemical synthesis of the authentic standard. The in vitrosynthesis of AcTMCM was dependent on acetyl-CoA, whereas in vivo[14C]-acetate pulse–chase labeling showed that this lipid was rapidly synthesized and turned over in wild-type and genetically complemented bacterial strains. Significantly, the biochemical and TMCM/TDCM transport phenotype observed in the ΔNCgl2759mutant was phenocopied by inhibition of the activities of the two C. glutamicumMmpL3 homologues. Collectively, these data suggest that NCgl2759 is a novel TMCM mycolyl acetyltransferase (TmaT) that regulates transport of TMCM and is a potential drug target in pathogenic species.