Coexistence of blaNDM-5, blaCTX-M-15, blaOXA-232, blaSHV-182 genes in multidrug-resistant K. pneumoniae ST437-carrying OmpK36 and OmpK37 porin mutations: First report in Italy

OBJECTIVES

K. pneumoniae is a common cause of severe hospital-acquired infections. In the present study, we have characterised the whole-genome of two K. pneumoniae ST437 belonging to the clonal complex CC258.

METHODS

The whole-genome sequencing was performed by MiSeq Illumina, with a 2 × 300bp paired-end run. ResFinder 4.4.2 was used to detect acquired antimicrobial resistance genes (ARGs) and chromosomal mutations. Mobile genetic elements (plasmids and ISs) were identified by MobileElementFinder v1.0.3. The genome was also assigned to ST using MLST 2.0.9. Virulence factors were detected using the Virulence Factor Database (VFDB).

RESULTS

K. pneumoniae KPNAQ_1/23 and KPNAQ_2/23 strains, isolated from urine samples of hospitalised patients, showed resistance to most antibiotics, including ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam combinations. Both strains were susceptible only to cefiderocol. Multiple mechanisms of resistance were identified. Resistance to β-lactams was due to the presence of NDM-5, OXA-232, CTX-M-15, SHV-182 β-lactamases, and OmpK36 and OmpK37 porin mutations. Resistance to fluoroquinolones was mediated by chromosomal mutations in acrR, oqxAB efflux pumps, and the bifunctional gene aac(6')-Ib-cr.

CONCLUSION

The presence of different virulence genes makes these KPNAQ_1/23 and KPNAQ_2/23 high-risk clones.

Case series of

In the European Union between 2008 and 2017 there was a statistically significant decrease in the confirmed cases of salmonellosis. Nevertheless, it represents the first cause of food-borne outbreaks and the secondly most frequently reported zoonosis. Considering the pathogen diffusion and clinical consequences, monitoring the incidence of Salmonella spp. infections is a priority for public health. The study is aimed at describing the temporal trend of prevalence of Salmonella spp. positive tested and serotypes characteristics of the isolates by L’Aquila hospital laboratory microbiological analysis in 2011-2018, with a focus on the epidemic phase occurred from October 2013 to May 2014. The survey is a case series report, with a retrospective design. During the period considered, 220 infected carriers were identified, in particular 160 positive samples for Salmonella enterica serogroup B, so it was the main group causing salmonellosis in the area of L’Aquila both in the epidemic period and in the non-epidemic period. Moreover, the proportion of cases in early paediatric age (from one to five years) resulted statistically higher in the epidemic period than in the non-epidemic period. About the possible causes of the outbreak, the hypothesis of an environmental contamination seems to be plausible.

NOS2 expression in glioma cell lines and glioma primary cell cultures: correlation with neurosphere generation and SOX-2 expression

Nitric oxide has been implicated in biology and progression of glioblastoma (GBM) being able to influence the cellular signal depending on the concentration and duration of cell exposure. NOS2 (inducible nitric oxide synthase) have been proposed as a component of molecular profile of several tumors, including glioma, one of the most aggressive primary brain tumor featuring local cancer stem cells responsible for enhanced resistance to therapies and for tumor recurrence. Here, we investigated the NOS2 mRNA expression by reverse transcription-PCR in human glioma primary cultures at several grade of malignancy and glioma stem cell (GSC) derived neurospheres. Glioma cell lines were used as positive controls both in terms of stemness marker expression that of capacity of generating neurospheres. NOS2 expression was detected at basal levels in cell lines and primary cultures and appeared significantly up-regulated in cultures kept in the specific medium for neurospheres. The immunofluorescence analysis of all cell cultures to evaluate the levels of SOX-2, a stemness marker aberrantly up-regulated in GBM, was also performed. The potential correlation between NOS2 expression and ability to generate neurospheres and between NOS2 and SOX-2 levels was also verified. The results show that the higher NOS2 expression is detected in all primary cultures able to arise neurosphere. A high and significant correlation between NOS2 expression and SOX-2 positive cells (%) in all cell cultures maintained in standard conditions has been observed. The results shed light on the potential relevance of NOS2 as a prognostic factor for glioma malignancy and recurrence.

Nitric Oxide Chemical Donor Affects the Early Phases of In Vitro Wound Healing Process

An artificial wound in a confluent monolayer of human keratinocyte HaCaT cells or mouse embryo fibroblast Swiss NIH 3T3 cells was used to analyze the effects of the nitric oxide (NO) chemical donor, S-nitroso-N-acetylpenicillamine (SNAP). SNAP exposure promoted an enhanced rate of wound closure and accelerated motility of both keratinocytes and fibroblasts compared to control cells. The wounded monolayer cultures of HaCaT and NIH 3T3 cells, treated with or without SNAP, were monitored under a phase contrast microscope. Structural and ultrastructural modifications were analyzed by scanning electron microscopy (SEM). The images were captured by a digital camera at different time points (0-28 h) and the wound area was analyzed through software included in Matlab®. As early as 15 min, SNAP induced significant cytoskeletal remodeling, as shown by immunostaining (phalloidin-labelling), which in turn was associated with increased filopodium number and length rise. NO donor treatment also induced overexpression of Ki-67 protein, a typical marker of cell proliferation, as shown by immunostaining. Both SNAP-induced migration and proliferation were antagonized by the NO-sensitive GC inhibitor 1H-[1,2,4]oxadiazolo[-4,3-a]quinoxalin-1-one (ODQ), which suggests activation of the NO/cGMP signalling cascade in the observed SNAP-induced effects in the early stages of the healing process. Moreover, we provide evidence that PPAR-β antagonist (GSK0660) may interfere with NO-mediated wound healing process. J. Cell. Physiol. 231: 2185-2195, 2016. © 2016 Wiley Periodicals, Inc.

Immunophenotypic characterization of human glioblastoma stem cells: correlation with clinical outcome

Recently, glioma stem cells have been identified as the main cause of glioma propagation and recurrence and a number of several cell markers have been indicated as putative GSC markers. In the present work, a retrospective study to evaluate the prognostic potential of ability to generate GSCs in our series of 15 glioblastoma patients is described. β-tubulin III, nestin, CD133, GFAP, and SOX-2 marker expression, both in primary GBM cultures and in respective glioblastoma stem cells (GSCs), was evaluated by flow cytometric analysis. Our results demonstrated various expression levels of these markers in both cell cultures; of note, only those cells expressing SOX-2 at greater than 30% levels were able to produce in vitro neurospheres. Moreover, statistical analysis revealed that the GSCs generation negatively affected overall survival (OS) (P = 0.000) and progression-free survival (PFS) (P = 0.001). In addition, a very poor OS (P = 0.000) and PFS (P = 0.000) were observed among patients whose tumors expressed Ki67, evaluated by immunohistochemistry, and showed the ability to generate in vitro GSCs. Overall, the results suggest that in vitro GSCs generation associated to the expression of Ki67 and SOX-2 may be useful to identify patients at risk of disease progression.

In vitro evaluation of different methods of handling human liposuction aspirate and their effect on adipocytes and adipose derived stem cells

Nowadays, fat tissue transplantation is widely used in regenerative and reconstructive surgery. However, a shared method of lipoaspirate handling for ensuring a good quality fat transplant has not yet been established. The study was to identify a method to recover from the lipoaspirate samples the highest number of human viable adipose tissue-derived stem cells (hADSCs) included in stromal vascular fraction (SVF) cells and of adipocytes suitable for transplantation, avoiding an extreme handling. We compared the lipoaspirate spontaneous stratification (10-20-30 min) with the centrifugation technique at different speeds (90-400-1500 × g). After each procedure, lipoaspirate was separated into top oily lipid layer, liquid fraction, "middle layer", and bottom layer. We assessed the number of both adipocytes in the middle layer and SVF cells in all layers. The histology of middle layer and the surface phenotype of SVF cells by stemness markers (CD105+, CD90+, CD45-) was analyzed as well. The results showed a normal architecture in all conditions except for samples centrifuged at 1500 × g. In both methods, the flow cytometry analysis showed that greater number of ADSCs was in middle layer; in the fluid portion and in bottom layer was not revealed significant expression levels of stemness markers. Our findings indicate that spontaneous stratification at 20 min and centrifugation at 400 × g are efficient approaches to obtain highly viable ADSCs cells and adipocytes, ensuring a good thickness of lipoaspirate for autologous fat transfer. Since an important aspect of surgery practice consists of gain time, the 400 × g centrifugation could be the recommended method when the necessary instrumentation is available.

Biological Effects of Low Frequency High Intensity Ultrasound Application on EX Vivo Human Adipose Tissue

In the present work the effects of a new low frequency, high intensity ultrasound technology on human adipose tissue ex vivo were studied. In particular, we investigated the effects of both external and surgical ultrasound-irradiation (10 min) by evaluating, other than sample weight loss and fat release, also histological architecture alteration as well apoptosis induction. The influence of saline buffer tissue-infiltration on the effects of ultrasound irradiation was also examined. The results suggest that, in our experimental conditions, both transcutaneous and surgical ultrasound exposure caused a significant weight loss and fat release. This effect was more relevant when the ultrasound intensity was set at 100% (∼ 2.5 W/cm2 for external device; ∼19–21 W/cm2, for surgical device) compared to 70% (∼ 1.8 W/cm2 for external device; ∼13–14 W/cm2 for surgical device). Of note, the effectiveness of ultrasound was much higher when the tissue samples were previously infiltrated with saline buffer, in accordance with the knowledge that ultrasonic waves in aqueous solution better propagate with a consequently more efficient cavitation process. Moreover, the overall effects of ultrasound irradiation did not appear immediately after treatment but persisted over time, being significantly more relevant at 18 h from the end of ultrasound irradiation. Evaluation of histological characteristics of ultrasound-irradiated samples showed a clear alteration of adipose tissue architecture as well a prominent destruction of collagen fibers which were dependent on ultrasound intensity and most relevant in saline buffer-infiltrated samples. The structural changes of collagen bundles present between the lobules of fat cells were confirmed through scanning electron microscopy (SEM) which clearly demonstrated how ultrasound exposure induced a drastic reduction in the compactness of the adipose connective tissue and an irregular arrangement of the fibers with a consequent alteration in the spatial architecture. The analysis of the composition of lipids in the fat released from adipose tissue after ultrasound treatment with surgical device showed, in agreement with the level of adipocyte damage, a significant increase mainly of triglycerides and cholesterol. Finally, ultrasound exposure had been shown to induce apoptosis as shown by the appearance DNA fragmentation. Accordingly, ultrasound treatment led to down-modulation of procaspase-9 expression and an increased level of caspase-3 active form.

Effects of phosphatidylcholine and sodium deoxycholate on human primary adipocytes and fresh human adipose tissue

Recent studies introduced the novel concept of chemical lipolysis where phosphatidylcholine (PC), an active component of commercial preparations, plays a pivotal role. Other studies suggested that sodium deoxycholate (DOC), an excipient contained in medical preparations, could be the real active component performing an adipocytolytic action. We investigated the effects of PC and DOC on human primary adipocyte cultures and on human fresh adipose tissue. Human adipocytes isolated by Rodbell's method, were cultured onto type I collagen-coated glass coverslips, placed into 24-well tissue culture plates. Cells were incubated with or without DOC (5-7-9%), PC (5%) or DOC/PC mixture and observed under phase contrast microscope. After incubation, cells were stained with Oil Red-O and with acridine orange/ethidium bromide to observe necrotic cells with phase contrast microscope and fluorescent microscope, respectively. Histological specimens from adipose tissue biopsies were observed with phase contrast microscopy and with scanning electron microscopy. To investigate the lipid pattern variability in the different experimental conditions, culture medium obtained from the different treatments was subjected to lipid extraction and subsequently to thin layer chromatography (TLC). Microscopic observation of adipocytes showed that DOC treatment led to a detrimental morphological effect in a dose-dependent manner. PC treatment did not significantly affect adipocyte viability. On the contrary, results from experiments aimed to analyze the effects of PC/DOC combined treatment suggested a PC protective role against the DOC harmful effects on adipocytes. Results indicated that clinical effects, observed in local treatment with pharmaceutical preparation, could be due only to DOC, a detergent inducing nonspecific lysis of cell membranes following adipocyte necrosis. On the other hand, PC could likely be incorporated in the lipid bilayer, thus strongly reducing the disruptive DOC effects.

Surgical treatment of hepatic metastatic colorectal cancer

73 patients (men age 54 years, range 17-78), underwent an hepatic resection for metastatic, colorectal cancer. Operative mortality was 1.36% Overall 5 years survival rate (Kaplan-Meier) was 27%; 5 years disease free interval was equally 27%. This could demonstrate that 5 years survivors could be also considered free from the risk of metastatic recurrence. This is confirmed by our survivors over 5 years (70-79-94 months) that are still disease free.

[Proctocolectomy and mechanical ileo-anal anastomosis without mucosectomy]

The present study compared the outcome in a small series of patients (7 cases) who underwent total proctocolectomy without mucosal proctectomy and stapled ileal pouch-anal anastomosis, constructed at the apex of the anal transitional zone, with our previous experience (17 cases) in which the ileal pouch was anastomosed at the dentate line after mucosectomy. Though not statistically significant, our limited experience showed excellent clinical results with better continence and discriminating ability between gas and faeces in the former group. The resting anal pressure profile showed no chances in the postoperative period. The operation time was significantly reduced compared with our previous approach which was a time-consuming procedure. Furthermore, a reduced risk of complications (pelvic sepsis, haemorrhage) was observed.