Characterization of the multidrug efflux transporter styMdtM from Salmonella enterica serovar Typhi.

Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) isolates constitutively express the styMdtM (STY4874) gene, which encodes a known multidrug-resistance (MDR) transporter. Guided by the structure of the Escherichia coli (E. coli) homolog, we studied two residues critical for substrate transport, Asp25 and Arg111. Mutation of Asp25 to glutamate did not affect the transport function of styMdtM, whereas mutation to alanine reduced its transport activity, suggesting that a negative charge at this position is critical for substrate translocation across the membrane. Substrate-affinity measurements by intrinsic fluorescence spectroscopy showed that the Asp25Ala mutant retained its capacity to bind substrate, albeit at a lower level. Mutation of Arg111 to alanine resulted in a decrease in secondary structure content of the transporter, and mutation to lysine completely destabilized the structure of the transporter. A homology model of styMdtM suggests that Arg111 is important for stabilizing the transmembrane domain by mediating necessary interactions between neighboring helices. Together, our studies provide new structural and mechanistic insights into the Salmonella MDR transporter styMdtM.

Multidisciplinary team (MDT) meeting and Radiologist workload, a prospective review in a tertiary care hospital.

OBJECTIVE: To quantify the increase in workload associated with multidisciplinary team meetings for radiologists in a tertiary care hospital over a period of 15 months. METHODS: Data was collected prospectively regarding number of multidisciplinary team meetings, number of clinical cases discussed, number of individual imaging studies reviewed, and preparation time of residents, senior registrar and consultants and the delivery time of meeting. RESULTS: Total 223 meetings were held over 15 months (April 2014 to June 2015) for 12 clinical specialty areas. There were 1120 clinical case discussions and a total of 2759 documented individual imaging studies reviewed. Resident's preparation time was 74.6 hours/month, senior registrar's preparation time was 47.93 hours/month, consultant's preparation time was 18.67 hours/month and the total duration time for meetings was 18 hours/month. CONCLUSION: Multidisciplinary team meetings now represent a significant workload of radiology and has reduced the time for other academic activities within the department.

Identification of additional mechanistically important residues in the multidrug transporter styMdtM of Salmonella Typhi.

Multidrug efflux is a well-established mechanism of drug resistance in bacterial pathogens like Salmonella Typhi. styMdtM (locus name; STY4874) is a multidrug efflux transporter of the major facilitator superfamily expressed in S. Typhi. Functional assays identified several residues important for its transport activity. Here, we used an AlphaFold model to identify additional residues for analysis by mutagenesis. Mutation of peripheral residue Cys185 had no effect on the structure or function of the transporter. However, substitution of channel-lining residues Tyr29 and Tyr231 completely abolished transport function. Finally, mutation of Gln294, which faces peripheral helices of the transporter, resulted in the loss of transport of some substrates. Crystallization studies yielded diffraction data for the wild-type protein at 4.5 Å resolution and allowed the unit cell parameters to be established as a = b = 64.3 Å, c = 245.4 Å, α = ß = γ = 90°, in space group P4. Our studies represent a further stepping stone towards a mechanistic understanding of the clinically important multidrug transporter styMdtM.Communicated by Ramaswamy H. Sarma.

Mapping Current Organizational Structure and Improvement Points of Breast Cancer Multidisciplinary Team Meetings - An Interview Study.

Purpose: The aim of the study was to map current organization, and document potential improvement points of breast cancer multidisciplinary team meetings (MDTMs), in order to support the optimization of the present breast cancer MDTM organization. Methods: From January 2019 to February 2021, 24 core team members of the breast cancer multidisciplinary team (MDT) in three hospitals were interviewed. Semi-structured interviews were performed based on an interview guide. All interviews were recorded and transcribed verbatim. Deductive coding was performed on the transcripts by two independent researchers. The codes were organized in categories and themes. Results: In total 24 healthcare professionals; surgeons, medical oncologists, radiotherapists, pathologists, radiologists, and specialized nurses, from three different hospitals were interviewed. According to the participants, improving efficiency before and during MDTMs is possible by ensuring proper preparation of attendees, implementing more structure during discussions, improving access to and availability of patient data and optimizing general meeting discipline. Conclusion: Preparation, structure, data availability and meeting discipline were highlighted as essential factors for efficient breast cancer MDTM improvement. These topics seem to be applicable to other types of oncology MDTMs as well. Improving MDTM efficiency on the long term ensures high-quality discussions for all breast cancer patients.

Bactericidal Properties of Proline-Rich Aedes aegypti Trypsin Modulating Oostatic Factor (AeaTMOF).

The antimicrobial properties of proline-rich Aedes aegypti decapeptide TMOF (AeaTMOF) and oncocin112 (1-13) were compared. Incubations with multidrug-resistant Escherichia coli cells showed that AeaTMOF (5 mM) was able to completely inhibit bacterial cell growth, whereas oncocin112 (1-13) (20 mM) partially inhibited bacterial growth as compared with bacterial cells that were not multidrug-resistant cells. AeaTMOF (5 mM) was very effective against Acinetobacter baumannii and Pseudomonas aeruginosa, completely inhibiting cell growth during 15 h incubations. AeaTMOF (5 mM) completely inhibited the Gram-positive bacteria Staphylococcus aureus and Bacillus thurengiensis sups. Israelensis cell growth, whereas oncocin112 (1-13) (10 and 20 mM) failed to affect bacterial cell growth. E. coli cells that lack the SbmA transporter were inhibited by AeaTMOF (5 mM) and not by oncocin112 (1-13) (10 to 20 mM), indicating that AeaTMOF can use other bacterial transporters than SbmA that is mainly used by proline-rich antimicrobial peptides. Incubation of E. coli cells with NaAzide showed that AeaTMOF does not use ABC-like transporters that use ATP hydrolysis to import molecules into bacterial cells. Three-dimensional modeling and docking of AeaTMOF to SbmA and MdtM transporters showed that AeaTMOF can bind these proteins, and the binding location of AeaTMOF inside these protein transporters allows AeaTMOF to be transported into the bacterial cytosol. These results show that AeaTMOF can be used as a future antibacterial agent against both multidrug-resistant Gram-positive and -negative bacteria.

Impact of Multidisciplinary Team Management on the Survival Rate of Head and Neck Cancer Patients: A Cohort Study Meta-analysis.

Background: Head and neck cancer (HNC) is one of the more common malignant tumors that threaten human health worldwide. Multidisciplinary team management (MDTM) in HNC treatment has been introduced in the past several decades to improve patient survival rates. This study reviewed the impact of MDTM on survival rates in patients with HNC compared to conventional treatment methods. Methods: Only cohort studies were identified for this meta-analysis that included an exposure group that utilized MDTM and a control group. Heterogeneity and sensitivity also were assessed. Survival rate data for HNC patients were analyzed using RevMan 5.2 software. Results: Five cohort studies (n = 39,070) that examined survival rates among HNC patients were included. Hazard ratios (HR) were calculated using the random effect model. The results revealed that exposure groups treated using MDTM exhibited a higher survival rate [HR = 0.84, 95% CI (0.76-0.92), P = 0.0004] with moderate heterogeneity (I 2 = 68%, p = 0.01). For two studies that examined the effect of MDTM on the survival rate for patients specifically with stage IV HNC, MDTM did not produce any statistically significant improvement in survival rates [HR = 0.81, 95% CI (0.59-1.10), p = 0.18]. Conclusions: The application of MDTM based on conventional surgery, radiotherapy, and chemotherapy improved the overall survival rate of patients with HNC. Future research should examine the efficacy of MDTM in patients with cancer at different stages.

Reorganizing the Multidisciplinary Team Meetings in a Tertiary Centre for Gastro-Intestinal Oncology Adds Value to the Internal and Regional Care Pathways. A Mixed Method Evaluation.

INTRODUCTION: The reorganisation of the structure of a Gastro-Intestinal Oncology Multidisciplinary Team Meeting (GIO-MDTM) in a tertiary centre with three care pathways is evaluated on added value. METHODS: In a mixed method investigation, process indicators such as throughput times were analysed and stakeholders were interviewed regarding benefits and drawbacks of the reorganisation and current MDTM functioning. RESULTS: For the hepatobiliary care pathway, the time to treatment plan increased, but the time to start treatment reduced significantly. The percentage of patients treated within the Dutch standard of 63 days increased for the three care pathways. From the interviews, three themes emerged: added value of MDTMs, focus on planning integrated care and awareness of possible improvements. DISCUSSION: The importance of evaluating interventions in oncology care pathways is shown, including detecting unexpected drawbacks. The evaluation provides insight into complex dynamics of the care pathways and contributes with recommendations on functioning of an MDTM. CONCLUSIONS: Throughput times are only partly determined by oncology care pathway management, but have influence on the functioning of MDTMs. Process indicator information can help to reflect on integration of care in the region, resulting in an increase of patients treated within the Dutch standard.