Elucidating constraints for differentiation of major human Klebsiella pneumoniae clones using MALDI-TOF MS

The establishment of matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS) in routine microbial identification boosted many developments towards high-throughput applications, including bacterial typing. However, results are still controversial for different bacterial species. We aim to evaluate the suitability of MALDI-TOF MS for typing clinically relevant multidrug resistant (MDR) Klebsiella pneumoniae subsp. pneumoniae clones using routine conditions and a previously validated chemometric analysis workflow. Mass spectra of 83 K. pneumoniae clinical isolates representing major human MDR clones [11 sequence types (STs), 22 PFGE-types] recovered in Portugal and Spain during outbreaks and non-outbreak situations (2003-2012) were obtained from cell extracts (CE) and intact cells (IC), and analysed with different chemometric tools. We observed a highly consistent peak pattern among isolates from different clones either with CE or IC, suggesting a high degree of conservation of biomolecules analysed (a large part corresponding to ribosomal proteins). Moreover, the low degree of agreement between MALDI-TOF MS and other methods (from 34.9 % to 43.4 % of correct assignments for CE and from 40.8 % to 70.1 % for IC) corroborates the low discriminatory potential of the technique at infraspecies level. Our results suggest a low discriminatory power of MALDI-TOF MS for clinically relevant MDR K. pneumoniae clones and highlight the need of developing tools for high-resolution typing in this species.

[Bilateral submandibulectomy for the treatment of drooling in pediatric age: 10 years of experience]

INTRODUCTION

Sialorrhea is a medical problem and can become a social issue, common in children with neurological disabilities. The bilateral submandibulectomy is one of the available treatment options for managing this pathology.

AIM OF THE STUDY

The aim of this study is to evaluate the effectiveness of bilateral submandibulectomy in the management of sialorrhea in children with neurological disabilities through the parents' satisfaction grade.

PATIENTS AND METHODS

We retrospectively analyzed 91 bilateral submandibulectomies for a period of time of 10 years (2004-2015). Data were taken from surgical records and patients files and were informatically processed. The severity grade before and after surgery was evaluated in line with the modified Teacher scale. Parental satisfaction was evaluated by applying a scale graded into five classes, according to the degree of sialorrhea severity in postoperative period.

RESULTS

During the reporting period, 91 children underwent bilateral submandibulectomy in our center. Of these, 7 cases were excluded for lack of data. The average age of the children was 8,9 [± 3,5] years; 58,3% were male. The degree of preoperative sialorrhea severity was, in 52,4% of cases, level 4 (severe drooling), and in 28,6%, level 5 (very severe). The grade of parental satisfaction in postoperative period was ranked, in 73,8% of cases, between 81-100%.

CONCLUSIONS

For children with drooling, a bilateral submandibulectomy emerges as an effective and efficient treatment, leaving parents with an extremely high satisfaction grade.

Molecular picture of cobalamin C/D defects before and after newborn screening era

Objective

Birth prevalence of Cobalamin (Cbl) C or D defects in Portugal is an estimated 1:85,000, one of the highest worldwide. We compared the genotype/phenotype of patients identified with CblC or CblD before and after the implementation of expanded newborn screening.

Methods

Twenty-five Portuguese CblC/D patients, 14 symptomatic and 11 identified through screening, were diagnosed using gas chromatography or tandem mass spectrometry. Molecular characterization was performed through the study of MMACHC and MMADHC genes.

Results

The most common MMACHC mutation, c.271dupA, was present in 100% of MMACHC alleles of all CblC screened patients, in contrast with the 61% identified before expanded newborn screening. All studied cases (except one, who presented a CblD deficiency) presented a CblC defect. More CblC late-onset patients were diagnosed before the introduction of newborn screening than in the post newborn screening era, probably because some early onset patients died without a definitive diagnosis.

Conclusion

The molecular data found in this cohort contribute to the improvement of screening and diagnosis of Cbl defects and would enable a confirmatory diagnosis of these patients, reducing the need for complex, costly, laborious, and time-consuming biochemical/enzymatic tests.

Relationships of Echium plantagineum L. bee pollen, dietary flavonoids and their colonic metabolites with cytochrome P450 enzymes and oxidative stress

Echium plantagineumL. bee pollen is a dietary source of flavonoids, which can play a protective role in the gastrointestinal tract by modulating cytochrome P450 (CYP) biotransformation enzymes and by opposing oxidative stress.

Fatty acids from edible sea hares: anti-inflammatory capacity in LPS-stimulated RAW 264.7 cells involves iNOS modulation

The inclusion of marine organisms in the diet is gaining importance due to their richness in health beneficial nutrients.

Pennyroyal and gastrointestinal cells: multi-target protection of phenolic compounds against t-BHP-induced toxicity

Pennyroyal infusion maintains gastrointestinal cells antioxidant balance.

Antimicrobial synergism against different lineages of methicillin-resistant Staphylococcus aureus carrying SCCmec IV

AIM

To evaluate the synergistic activity of antimicrobial drugs against lineages of methicillin-resistant Staphylococcus aureus (MRSA) carrying SCCmec IV. The biofilm production and related genes were also detected.

METHODS AND RESULTS

Forty two MRSA isolates were tested for biofilm production and related genes. Biofilm/biomass susceptibility to gentamicin (G), linezolid (L), rifampicin (R) and vancomycin (V) was determined for six isolates from three lineages prevalent in Rio de Janeiro hospitals in concentrations ranging from 0·25 to 64 μg ml(-1). Biomass was evaluated by microtitre plate test and number of viable cells (CFU cm(-2)) and inspected by epifluorescence microscopy. All isolates presented the icaA and sasG genes, but only 38% were biofilm producers. There were 50 and 45% biomass reductions when concentrations ≥4 μg ml(-1) of R or L and ≥16 μg ml(-1) of G or V, respectively, were used. Synergism tests produced a 55% biomass reduction with R(2μgml-1) + G(16μgml-1), R(2μgml-1) + L(2μgml-1), R(2μgml-1) + V(4μgml-1), and L(2μgml-1) + V(4μgml-1). Number of viable cells was reduced from 2 to 3 logs with R(2μgml-1) + L(2μgml-1) and R(2μgml-1) + V(4μgml-1).

CONCLUSIONS

Synergisms involving R plus L and R plus V caused important reductions in biofilm/biomass and the number of viable cells. Drug combinations should be considered in the chemotherapies of MRSA-SCCmec IV infections.

SIGNIFICANCE AND IMPACT OF THE STUDY

Biofilms in MRSA infections restrict the clinical choice of antimicrobials. Thus, knowledge of the best options for monotherapy and drug synergisms could improve clinical results.

MALDI-TOF mass spectrometry as a tool for the discrimination of high-risk Escherichia coli clones from phylogenetic groups B2 (ST131) and D (ST69, ST405, ST393)

Reliable, quick and low-cost methods are needed for the early detection of multidrug-resistant and highly virulent high-risk B2 and D Escherichia coli clones or clonal complexes (HiRCC). Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) seems to have a good discriminatory potential at different subspecies levels, but it was never evaluated for the discrimination of E. coli clones. We assessed the potential of MALDI-TOF MS coupled to multivariate data analysis to discriminate representative E. coli B2 and D HiRCC. Seventy-three E. coli isolates from B2 (including ST131 and B2 non-ST131 clones) and D (ST69, ST393, ST405) with variable pulsed-field gel electrophoresis (PFGE) patterns, origins and dates (1980-2010) were tested. MS spectra were acquired from independent extracts obtained from different plate cultures in two different Microflex LT MALDI-TOF devices (Bruker) after a standard extraction procedure. MALDI-TOF MS fingerprinting analysis revealed a good discriminatory ability between the four HiRCC analysed (ST131, ST69, ST405, ST393) and between B2 ST131 and other B2 non-ST131 isolates. Clusters defined by MALDI-TOF MS were consistent with the clonal complexes assigned by multilocus sequence typing (MLST), although differences were detected regarding the composition of clusters obtained by the comparison of PFGE profiles. We demonstrate, for the first time, that characteristic mass fingerprints of different E. coli HiRCC are sufficiently discriminatory and robust to enable their differentiation by MALDI-TOF MS, which might represent a promising tool for the optimisation of infection control, individual patient management and large-scale epidemiological studies of public health relevance. The good correlation between phenotypic and genotypic features further corroborates phylogenetic relationships delineated by MLST.

An investigation of the potential application of chitosan/aloe-based membranes for regenerative medicine

A significant number of therapeutics derived from natural polymers and plants have been developed to replace or to be used in conjunction with existing dressing products. The use of the therapeutic properties of aloe vera could be very useful in the creation of active wound dressing materials. The present work was undertaken to examine issues concerning structural features, topography, enzymatic degradation behavior, antibacterial activity and cellular response of chitosan/aloe vera-based membranes. The chitosan/aloe vera-based membranes that were developed displayed satisfactory degradation, roughness, wettability and mechanical properties. A higher antibacterial potency was displayed by the blended membranes. Moreover, in vitro assays demonstrated that these blended membranes have good cell compatibility with primary human dermal fibroblasts. The chitosan/aloe vera-based membranes might be promising wound dressing materials.