New contributions on chronic low back pain: disc infection or contaminated cultures?

BACKGROUND

There is controversy about the likely infectious origin of chronic low back pain, because it has been suggested the possibility of a relationship with infection by Cutibacterium acnes (C. acnes).

HYPOTHESIS

The aim of this study is to compare four methods to determine the presence of a likely infection caused by C. acnes in surgical disc samples.

PATIENTS AND METHODS

This work is a cross-sectional observational study in which there are included 23 patients with microdiscectomy indication. Disc samples were taken during surgery and analysis was done by culture, Sanger sequencing, Next-Generation Sequencing (NGS), and real-time PCR (qPCR). Furthermore, clinical data collection was conducted, and it was analysed the presence of the Modic-like changes on the magnetic resonance imaging.

RESULTS

In 5 of the samples from among the 23 patients (21.7%) C. acnes was isolated by culture. However, in none of the samples could its genome be detected through Sanger sequencing, the less sensitive method. Only the qPCR and NGS were able to detect very few copies of the genome of this microorganism in all the samples, with no significant quantitative differences being observed between the patients in whom isolation of the microorganism by culture was evident or not. Further, there were no significant relationships identified between the clinical variables, including Modic alterations and positive cultures.

DISCUSSION

The most sensitive methods to the detect C. acnes were NGS and qPCR. The data obtained do not suggest association between the presence of C. acnes and the clinical process and support the hypothesis that C. acnes is found in these samples only because it is a contamination from the skin microbiome.

Evaluation of the validity of Ag PANBIO-COVID19 in the diagnosis of SARS-CoV-2 infection in asymptomatic or mildly infected patients

Objective. To assess the validity of SARS-CoV-2 Antigen (Ag) detection for the diagnosis of SARS-CoV-2 infection in mildly infected or asymptomatic patients. Material and methods. Observational study to evaluate diagnostic tests. Non-hospitalized patients with indication for diagnostic testing for SARS-CoV-2 infection were included. The diagnostic test to be evaluated was the determination of Ag and as a reference standard to determine the presence of viral RNA the RT-PCR was used. Results. A total of 494 patients were included. Of these 71.5% (353/494) had symptoms and 28.5% (141/494) were asymptomatic (presurgery screening (35/494) and confirmed case-contact (106/494). The overall sensitivity of the Ag test was 61.1% and the specificity was 99.7%. The sensitivity and specificity in the asymptomatic group were 40% and 100% respectively, and in the symptomatic group 63.5% and 99.6% respectively. In turn, the sensitivity and specificity in the group of symptomatic patients varied according to the time of symptom evolution: in patients with recent symptoms, they were 71.4% and 99.6% respectively, while in patients with symptoms of more than 5 days of evolution, they were 26.7% and 100% respectively. In all groups studied, the presence of antigen is associated with a high viral load (Ct<30 cycles). Conclusions. The use of Ag detection test is not indicated for the diagnosis of SARS-CoV-2 infection in asymptomatic patients or with symptoms of more than 5 days of evolution, but it could be useful in patients with symptoms of 1-5 days of evolution.

Impact of Sepsis Flow Chip, a novelty fast microbiology method, in the treatment of bacteremia caused by Gram-negative bacilli

Objective

The aim of this study was to assess the impact of the information provided by the new Sepsis Chip Flow system (SFC) and other fast microbiological techniques on the selection of the appropriate antimicrobial treatment by the clinical researchers of an antimicrobial stewardship team.

Methods

Two experienced clinical researchers performed the theoretical exercise of independently selecting the treatment for patients diagnosed by bacteremia due to bacilli gram negative (BGN). At first, the clinicians had only available the clinical characteristics of 74 real patients. Sequentially, information regarding the Gram stain, MALDI-TOF, and SFC from Vitro were provided. Initially, the researchers prescribed an antimicrobial therapy based on the clinical data, later these data were complementing with information from microbiological techniques, and the clinicians made their decisions again.

Results

The data provided by the Gram stain reduced the number of patients prescribed with combined treatments (for clinician 1, from 23 to 7, and for clinician 2, from 28 to 12), but the use of carbapenems remained constant. In line with this, the data obtained by the MALDI-TOF also decreased the combined treatment, and the use of carbapenems remained unchanged. By contrast, the data on antimicrobial resistance provided by the SFC reduced the carbapenems treatment.

Conclusions

From the theoretical model the Gram stain and the MALDI-TOF results achieved a reduction in the combined treatment. However, the new system tested (SFC), due to the resistance mechanism data provided, not only reduced the combined treatment, it also decreased the prescription of the carbapenems.

Differential Effects of IGF-1R Small Molecule Tyrosine Kinase Inhibitors BMS-754807 and OSI-906 on Human Cancer Cell Lines

Simple Summary

We have tested the effects of IGF-1R tyrosine kinase inhibitors BMS-754807 (BMS) and OSI-906 (OSI) on human colon, pancreatic carcinoma cell, and glioblastoma cell lines and primary cultures. Although OSI and BMS are able to inhibit IGF-1R activity at low doses, the differential effect on cell proliferation and cell-cycle phase distribution shown by both compounds probes that many effects observed are mediated by BMS off-target interactions. Using MAPKs ELISAs and phospho-RTK array analysis, we have identified several BMS regulated putative kinases able to mediate BMS off-target effects. Interestingly, molecular docking assays suggest that BMS could affect these kinases not only by blocking their ATP-binding domain, but also by means of allosteric interactions. Since BMS has an important antineoplastic effect on these poor prognosis types of cancer, these compounds could be taken in consideration for treatment independently of IGF-1R status.

Abstract

We have determined the effects of the IGF-1R tyrosine kinase inhibitors BMS-754807 (BMS) and OSI-906 (OSI) on cell proliferation and cell-cycle phase distribution in human colon, pancreatic carcinoma, and glioblastoma cell lines and primary cultures. IGF-1R signaling was blocked by BMS and OSI at equivalent doses, although both inhibitors exhibited differential antiproliferative effects. In all pancreatic carcinoma cell lines tested, BMS exerted a strong antiproliferative effect, whereas OSI had a minimal effect. Similar results were obtained on glioblastoma primary cultures, where HGUE-GB-15, -16 and -17 displayed resistance to OSI effects, whereas they were inhibited in their proliferation by BMS. Differential effects of BMS and OSI were also observed in colon carcinoma cell lines. Both inhibitors also showed different effects on cell cycle phase distribution, BMS induced G₂/M arrest followed by cell death, while OSI induced G₁ arrest with no cell death. Both inhibitors also showed different effects on other protein kinases activities. Taken together, our results are indicative that BMS mainly acts through off-target effects exerted on other protein kinases. Given that BMS exhibits a potent antiproliferative effect, we believe that this compound could be useful for the treatment of different types of tumors independently of their IGF-1R activation status.

Cell Death Mechanisms Induced by CLytA-DAAO Chimeric Enzyme in Human Tumor Cell Lines

The combination of the choline binding domain of the amidase N-acetylmuramoyl-L-alanine (CLytA)-D-amino acid oxidase (DAAO) (CLytA-DAAO) and D-Alanine induces cell death in several pancreatic and colorectal carcinoma and glioblastoma cell lines. In glioblastoma cell lines, CLytA-DAAO-induced cell death was inhibited by a pan-caspase inhibitor, suggesting a classical apoptotic cell death. Meanwhile, the cell death induced in pancreatic and colon carcinoma cell lines is some type of programmed necrosis. In this article, we studied the mechanisms that trigger CLytA-DAAO-induced cell death in pancreatic and colorectal carcinoma and glioblastoma cell lines and we acquire a further insight into the necrotic cell death induced in pancreatic and colorectal carcinoma cell lines. We have analyzed the intracellular calcium mobilization, mitochondrial membrane potential, PARP-1 participation and AIF translocation. Although the mitochondrial membrane depolarization plays a crucial role, our results suggest that CLytA-DAAO-induced cell death is context dependent. We have previously detected pancreatic and colorectal carcinoma cell lines (Hs766T and HT-29, respectively) that were resistant to CLytA-DAAO-induced cell death. In this study, we have examined the putative mechanism underlying the resistance in these cell lines, evaluating both detoxification mechanisms and the inflammatory and survival responses. Overall, our results provide a better understanding on the cell death mechanism induced by CLytA-DAAO, a promising therapy against cancer.

Etiology of bloodstream infections at a population level during 2013-2017 in the Autonomous Community of Valencia, Spain

Introduction

Bloodstream Infections has become in one of the priorities for the antimicrobial stewardship teams due to their high mortality and morbidity rates. Usually, the first antibiotic treatment for this pathology must be empirical, without microbiology data about the microorganism involved. For this reason, the population studies about the etiology of bacteremia are a key factor to improve the selection of the empirical treatment, because they describe the main microorganisms associated to this pathology in each area, and this data could facilitate the selection of correct antibiotic therapy.

Material and methods

This study describes the etiology of bloodstream infections in the Southeast of Spain. The etiology of bacteremia was analysed by a retrospective review of all age-ranged patients from every public hospital in the Autonomous Community of Valencia (approximately 5,000,000 inhabitants) for five years.

Results

A total of 92,097 isolates were obtained, 44.5% of them were coagulase-negative staphylococci. Enterobacteriales was the most prevalent group and an increase in frequency was observed along the time. Streptococcus spp. were the second microorganisms more frequently isolated. Next, the most prevalent were Staphylococcus aureus and Enterococcus spp., both with a stable incidence along the study. Finally, Pseudomonas aeruginosa was the fifth microorganism more frequently isolated.

Conclusions

These data constitute a useful tool that can help in the choice of empirical treatment for bloodstream infections, since the knowledge of local epidemiology is key to prescribe a fast and appropriate antibiotic therapy, aspect capital to improve survival.

Effect of Dalbavancin on Staphylococcal Biofilms When Administered Alone or in Combination With Biofilm-Detaching Compounds

Microorganisms grown in biofilms are more resistant to antimicrobial treatment and immune system attacks compared to their planktonic forms. In fact, infections caused by biofilm-forming Staphylococcus aureus and Staphylococcus epidermidis are a large threat for public health, including patients with medical devices. The aim of the current manuscript was to test the effect of dalbavancin, a recently developed lipoglycopeptide antibiotic, alone or in combination with compounds contributing to bacterial cell disaggregation, on staphylococcal biofilm formation and elimination. We used real-time impedance measurements in microtiter plates to study biofilm growth dynamics of S. aureus and S. epidermidis strains, in the absence or presence of dalbavancin, linezolid, vancomycin, cloxacillin, and rifampicin. Further experiments were undertaken to check whether biofilm-detaching compounds such as N-acetylcysteine (NAC) and ficin could enhance dalbavancin efficiency. Real-time dose–response experiments showed that dalbavancin is a highly effective antimicrobial, preventing staphylococcal biofilm formation at low concentrations. Minimum biofilm inhibitory concentrations were up to 22 higher compared to standard E-test values. Dalbavancin was the only antimicrobial that could halt new biofilm formation on established biofilms compared to the other four antibiotics. The addition of NAC decreased dalbavancin efficacy while the combination of dalbavancin with ficin was more efficient than antibiotic alone in preventing growth once the biofilm was established. Results were confirmed by classical biofilm quantification methods such as crystal violet (CV) staining and viable colony counting. Thus, our data support the use of dalbavancin as a promising antimicrobial to treat biofilm-related infections. Our data also highlight that synergistic and antagonistic effects between antibiotics and biofilm-detaching compounds should be carefully tested in order to achieve an efficient treatment that could prevent both biofilm formation and disruption.

CLytA-DAAO, Free and Immobilized in Magnetic Nanoparticles, induces Cell Death in Human Cancer Cells

D-amino acid oxidase (DAAO) catalyzes the oxidation of D-amino acids generating hydrogen peroxide, a potential producer of reactive oxygen species. In this study, we used a CLytA-DAAO chimera, both free and bound to magnetic nanoparticles, against colon carcinoma, pancreatic adenocarcinoma, and glioblastoma cell lines. We found that the enzyme induces cell death in most of the cell lines tested and its efficiency increases significantly when it is immobilized in nanoparticles. We also tested this enzyme therapy in non-tumor cells, and we found that there is not cell death induction, or it is significantly lower than in tumor cells. The mechanism triggering cell death is apparently a classical apoptosis pathway in the glioblastoma cell lines, while in colon and pancreatic carcinoma cell lines, CLytA-DAAO-induced cell death is a necrosis. Our results constitute a proof of concept that an enzymatic therapy, based on magnetic nanoparticles-delivering CLytA-DAAO, could constitute a useful therapy against cancer and besides it could be used as an enhancer of other treatments such as epigenetic therapy, radiotherapy, and treatments based on DNA repair.