In mixed infections, the bacterial susceptibility differs significantly compared to monocultures of bacteria, and generally the concentrations of antibiotics required for the treatment increases drastically. For S. aureus and P. aeruginosa dual species biofilms, it has been numerously reported that P. aeruginosa decreases S. aureus susceptibility to a broad range of antibiotics, including beta-lactams, glycopeptides, aminoglycosides, macrolides, while sensitizes to quinolones via secretion of various metabolites. Here we show that S. aureus also modulates the susceptibility of P. aeruginosa to antibiotics in mixed cultures. Thus, S. aureus—P. aeruginosa consortium was characterized by tenfold increase in susceptibility to ciprofloxacin and aminoglycosides compared to monocultures. The same effect could be also achieved by the addition of cell-free culture of S. aureus to P. aeruginosa biofilm. Moreover, similar increase in antibiotics efficacy could be observed following addition of S. aureus suspension to the P. aeruginosa mature biofilm, compared to P. aeruginosa monoculture, and vice versa. These findings open promising perspectives to increase the antimicrobial treatment efficacy of the wounds infected with nosocomial pathogens by the transplantation of the skin residential microflora.

Background: Surgical resection is considered to be the only potentially curative option for patients with pancreatic neuroendocrine tumors (pNETs). High risk rates of perioperative complications make minimally invasive ablative techniques a novel perspective and alternative treatment option for pancreatic neuroendocrine tumors. This study aims to present the first experience of using a microwave ablation in management of pNETs.Methods: Sechenov University has an experience of treating more than 400 patients with hormoneproducing tumors of the pancreas, 7 of which were treated by microwave ablation (MWA).Results: In all patients that underwent MWA, a regression of hormonal symptomatic was achieved. Two patients required readmission a month later for draining of pseudocyst and abscess. Conclusions:The exact role of microwave ablation in the treatment of non-metastatic pancreatic neuroendocrine tumors has not been defined yet. There is a lack of large prospective randomized studies and the reason for this is that local tumor destruction is indicated in selected cases only, thus making it difficult to analyze a large group of patients and assess long-term results of the treatment. However, microwave ablation allows to take a better control of symptoms in patients with hormone overproduction and in those with high risk of postoperative complications.

Insulinomatosis is characterized by monohormonality of multiple macro-tumors and micro-tumors that arise synchronously and metachronously in all regions of the pancreas, and often recurring hypoglycemia. One of the main characteristics of insulinomatosis is the presence of insulin-expressing monohormonal endocrine cell clusters that are exclusively composed of proliferating insulin-positive cells, are less than 1 mm in size, and show solid islet-like structure. It is presumed that insulinomatosis affects the entire population of β-cells. With regards to molecular genetics, this phenomenon is not related to mutation in MEN1 gene and is more similar to sporadic benign insulinomas, however, at the moment molecular genetics of this disease remains poorly investigated. NGS sequencing was performed with a panel of 409 cancer-related genes. Results of sequencing were analyzed by bioinformatic algorithms for detecting point mutations and copy number variations. DNA copy number variations were detected that harbor a large number of genes in insulinoma and fewer genes in micro-tumors. qPCR was used to confirm copy number variations at ATRX, FOXL2, IRS2 and CEBPA genes. Copy number alterations involving FOXL2, IRS2, CEBPA and ATRX genes were observed in insulinoma as well as in micro-tumors samples, suggesting that alterations of these genes may promote malignization in the β-cells population.

Klebsiella pneumoniae is a Gram-negative, encapsulated, non-motile bacterium, which represents a global challenge to public health as one of the major causes of healthcare-associated infections worldwide. In the recent decade, the World Health Organization (WHO) noticed a critically increasing rate of carbapenem-resistant K. pneumoniae occurrence in hospitals. The situation with extended-spectrum beta-lactamase (ESBL) producing bacteria further worsened during the COVID-19 pandemic, due to an increasing number of patients in intensive care units (ICU) and extensive, while often inappropriate, use of antibiotics including carbapenems. In order to elucidate the ways and mechanisms of antibiotic resistance spreading within the K. pneumoniae population, whole genome sequencing (WGS) seems to be a promising approach, and long-read sequencing is especially useful for the investigation of mobile genetic elements carrying antibiotic resistance genes, such as plasmids. We have performed short- and long read sequencing of three carbapenem-resistant K. pneumoniae isolates obtained from COVID-19 patients in a dedicated ICU of a multipurpose medical center, which belonged to the same clone according to cgMLST analysis, in order to understand the differences in their resistance profiles. We have revealed the presence of a small plasmid carrying aph(3′)-VIa gene providing resistance to amikacin in one of these isolates, which corresponded perfectly to its phenotypic resistance profile. We believe that the results obtained will facilitate further elucidating of antibiotic resistance mechanisms for this important pathogen, and highlight the need for continuous genomic epidemiology surveillance of clinical K. pneumoniae isolates.

Insulinoma is the most common pancreatic neuroendocrine tumor. Surgical management of insulinomas is considered to be the only curative method. However pancreatic surgery is associated with postoperative complications. The most difficult category of patients is patients previously operated on the pancreas. The aim is to show our experience of treatment patients with reoperated insulinomas. Materials and methods. 201 patients were operated because of insulinoma in the abdominal surgery department of Sechenov University from 1993 to 2019. 18 patients of them were reoperated. The authors describe their treatment experience of this category of patients. Results. The rate of reoperations in pancreatic insulinomas was 9%. Most of the tumors (12 of 18) were located in the head. Six patients were reoperated due to newly developed insulinomas. 12 patients were previously operated in other clinics but the tumors were not detected. This group of patients were the most complicated in imaging so we had to apply selective intra-arterial calcium stimulation test. All reoperated patients developed destructive pancreatitis in the postoperative period, five patients developed pancreatic fistula of classes B and C, two patients died. Conclusion. Accurate preoperative imaging carried out by an experienced team in reference center is an important factor for reducing the level of postoperative complications. Patients who had pancreatic surgery before should be treated by experienced multidisciplinary team.