Direct Observation of Gas-Phase Hydroxymethylene: Photoionization and Kinetics Resulting from Methanol Photodissociation

Carbene species play an integral role in high-energy chemistry, transition-metal-carbene chemistry, catalysis, photolytic formation of carbohydrates, and possibly even the formation of interstellar sugars. In 1921, "reactive formaldehyde"─now known as hydroxymethylene (HCOH)─was first implicated as an intermediate in photocatalytic processes. However, due to its transient nature, direct observation of HCOH has predominantly been attained using cryogenic isolation methods. As a result, HCOH gas-phase reactivity measurements have been limited. We directly observed HCOH using photoionization spectroscopy following UV photodissociation of methanol. Our measurements show it reacts slowly with O2 at room temperature. This work provides evidence for the formation mechanism of HCOH from CH3OH and its subsequent reactivity under gas-phase reaction conditions.

Evaluation of Rate Coefficients in the Gas Phase Using Machine-Learned Potentials

We assess the capability of machine-learned potentials to compute rate coefficients by training a neural network (NN) model and applying it to describe the chemical landscape on the C5H5 potential energy surface, which is relevant to molecular weight growth in combustion and interstellar media. We coupled the resulting NN with an automated kinetics workflow code, KinBot, to perform all necessary calculations to compute the rate coefficients. The NN is benchmarked exhaustively by evaluating its performance at the various stages of the kinetics calculations: from the electronic energy through the computation of zero point energy, barrier heights, entropic contributions, the portion of the PES explored, and finally the overall rate coefficients as formulated by transition state theory.

Continuous innovation in precision radio-guided surgery

Since its origins, nuclear medicine has faced technological changes that led to modifying operating modes and adapting protocols. In the field of radioguided surgery, the incorporation of preoperative scintigraphic imaging and intraoperative detection with the gamma probe provided a definitive boost to sentinel lymph node biopsy to become a standard procedure for melanoma and breast cancer. The various technological innovations and consequent adaptation of protocols come together in the coexistence of the disruptive and the gradual. As obvious examples we have the introduction of SPECT/CT in the preoperative field and Drop-in probes in the intraoperative field. Other innovative aspects with possible application in radio-guided surgery are based on the application of artificial intelligence, navigation and telecare.

Screening for chemicals with thyroid hormone-disrupting effects using zebrafish embryo

Thyroid disruption is an increasingly recognized issue in the use and development of chemicals and new drugs, especially to help toxicologist to complement the reproductive and developmental toxicology information of chemicals. Still, adequate assessment methods are scarce and often suffer a trade-off between physiological relevance and labor- and cost-intensive assays. Here, we present a tiered approach for a medium-throughput screening of chemicals to identify their thyroid disrupting potential in zebrafish embryos as a New Approach Methodology (NAM). After identifying the maximum tolerated concentrations, we exposed zebrafish larvae to sub-adverse effect levels of the reference compounds benzophenone-2, bisphenol A, phenylthiourea, potassium perchlorate, propylthiouracil, and phloroglucinol to exclude any systemic toxicity. Applying the transgenic zebrafish line that carries a gene for the red fluorescence protein (Tg(tg:mCherry)) under the thyroglobulin promoter, we could identify the thyroid disrupting effects of the chemicals by a time and cost-effective image analysis measuring the fluorescence levels in the thyroid glands. Our observations could be confirmed by altered expression patterns of genes involved in the hypothalamus-pituitary-thyroid (HPT) axis. Finally, to anchor the observed thyroid disruption, we determined some changes in the Thyroid hormone levels of triiodothyronine (T3) and Thyroxine (T4) using a newly developed liquid chromatography mass spectrometric (LCMS) method. The presented approach carries the potential to extend the toolbox for legislative authorities and chemical producers for the assessment of thyroid-specific endocrine disruption and to overcome current challenges in the evaluation of endocrine disruptors.

The Identity and Chemistry of C7H7 Radicals Observed during Soot Formation

We used aerosol mass spectrometry coupled with tunable synchrotron photoionization to measure radical and closed-shell species associated with particle formation in premixed flames and during pyrolysis of butane, ethylene, and methane. We analyzed photoionization (PI) spectra for the C₇H₇ radical to identify the isomers present during particle formation. For the combustion and pyrolysis of all three fuels, the PI spectra can be fit reasonably well with contributions from four radical isomers: benzyl, tropyl, vinylcyclopentadienyl, and o-tolyl. Although there are significant experimental uncertainties in the isomeric speciation of C₇H₇, the results clearly demonstrate that the isomeric composition of C₇H₇ strongly depends on the combustion or pyrolysis conditions and the fuel or precursors. Fits to the PI spectra using reference curves for these isomers suggest that all of these isomers may contribute to m/z 91 in butane and methane flames, but only benzyl and vinylcyclopentadienyl contribute to the C₇H₇ isomer signal in the ethylene flame. Only tropyl and benzyl appear to play a role during pyrolytic particle formation from ethylene, and only tropyl, vinylcyclopentadienyl, and o-tolyl appear to participate during particle formation from butane pyrolysis. There also seems to be a contribution from an isomer with an ionization energy below 7.5 eV for the flames but not for the pyrolysis conditions. Kinetic models with updated and new reactions and rate coefficients for the C₇H₇ reaction network predict benzyl, tropyl, vinylcyclopentadienyl, and o-tolyl to be the primary C₇H₇ isomers and predict negligible contributions from other C₇H₇ isomers. These updated models provide better agreement with the measurements than the original versions of the models but, nonetheless, underpredict the relative concentrations of tropyl, vinylcyclopentadienyl, and o-tolyl in both flames and pyrolysis and overpredict benzyl in pyrolysis. Our results suggest that there are additional important formation pathways for the vinylcyclopentadienyl, tropyl, and o-tolyl radicals and/or loss pathways for the benzyl radical that are currently unaccounted for in the present models.

Comprehensive Kinetics on the C7H7 Potential Energy Surface under Combustion Conditions

The automated kinetics workflow code, KinBot, was used to explore and characterize the regions of the C₇H₇ potential energy surface that are relevant to combustion environments and especially soot inception. We first explored the lowest-energy region, which includes the benzyl, fulvenallene + H, and cyclopentadienyl + acetylene entry points. We then expanded the model to include two higher-energy entry points, vinylpropargyl + acetylene and vinylacetylene + propargyl. The automated search was able to uncover the pathways from the literature. In addition, three important new routes were discovered: a lower-energy pathway connecting benzyl with vinylcyclopentadienyl, a decomposition mechanism from benzyl that results in side-chain hydrogen atom loss to produce fulvenallene + H, and shorter and lower energy routes to the dimethylene-cyclopentenyl intermediates. We systematically reduced the extended model to a chemically relevant domain composed of 63 wells, 10 bimolecular products, 87 barriers, and 1 barrierless channel and constructed a master equation using the CCSD(T)-F12a/cc-pVTZ//ωB97X-D/6-311++G(d,p) level of theory to provide rate coefficients for chemical modeling. Our calculated rate coefficients show excellent agreement with measured ones. We also simulated concentration profiles and calculated branching fractions from the important entry points to provide an interpretation of this important chemical landscape.

Automated Reaction Kinetics of Gas-Phase Organic Species over Multiwell Potential Energy Surfaces

Automation of rate-coefficient calculations for gas-phase organic species became possible in recent years and has transformed how we explore these complicated systems computationally. Kinetics workflow tools bring rigor and speed and eliminate a large fraction of manual labor and related error sources. In this paper we give an overview of this quickly evolving field and illustrate, through five detailed examples, the capabilities of our own automated tool, KinBot. We bring examples from combustion and atmospheric chemistry of C-, H-, O-, and N-atom-containing species that are relevant to molecular weight growth and autoxidation processes. The examples shed light on the capabilities of automation and also highlight particular challenges associated with the various chemical systems that need to be addressed in future work.

DockOnSurf: A Python Code for the High-Throughput Screening of Flexible Molecules Adsorbed on Surfaces

We present the open-source python package DockOnSurf which automates the generation and optimization of low-energy adsorption configurations of molecules on extended surfaces and nanoparticles. DockOnSurf is especially geared toward handling polyfunctional flexible adsorbates. The use of this high-throughput workflow allows us to carry out the screening of adsorbate-surface configurations in a systematic, customizable, and traceable way, while keeping the focus on the chemically relevant structures. The screening strategy consists in splitting the exploration of the adsorbate-surface configurational space into chemically meaningful domains, that is, by choosing among different conformers to adsorb, surface adsorption sites, adsorbate anchoring points, and orientations and allowing dissociation of (acidic) protons. We demonstrate the performance of the main features based on varying examples, ranging from CO adsorption on a gold nanoparticle to sorbitol adsorption on hematite. Through the use of the presented program, we aim to foster efficiency, traceability, and ease of use in research within tribology, catalysis, nanoscience, and surface science in general.

Custom designed radial forearm free flap for reconstruction of nasomaxillary defects: Report of two cases

Nasal amputation and nasomaxillary defects, need to reconstruct the internal lining, osteochondral structure, and external coating of the nose. Authors report a 70-year-old male and a 65-year-old female treated for nasomaxillary defects (Brown JS, Shaw RJ. The Lancet Oncology 2010;11:1001-1008) due to squamous cell carcinoma (SCC) where the tip of the nose was preserved. A new custom design of the radial forearm free flap (RFFF) consisting on a subcutaneous tissue (SCT) component, a skin paddle for the internal nasal vault lining, and a skin paddle for the external nasal skin coating was raised to treat both total thickness nasal defects. The dimension of each skin paddle corresponds to the defect measurements. The skin incisions of the custom design correspond to those of a conventional RFFF. The SCT component was harvested in a subcutaneous plane continuously with the skin island for the internal nasal lining which is drawn on the ulnar skin of the forearm. The component for the external nasal coating was drawn on the radial skin area of the flap. No postoperative complications and a satisfactory outcome was reported after 1 year of follow-up. This new custom design of the RFFF is described for reconstruction of nasomaxillary defects when the tip of the nose is preserved.

Density-functional tight-binding: basic concepts and applications to molecules and clusters

The scope of this article is to present an overview of the Density Functional based Tight Binding (DFTB) method and its applications. The paper introduces the basics of DFTB and its standard formulation up to second order. It also addresses methodological developments such as third order expansion, inclusion of non-covalent interactions, schemes to solve the self-interaction error, implementation of long-range short-range separation, treatment of excited states via the time-dependent DFTB scheme, inclusion of DFTB in hybrid high-level/low level schemes (DFT/DFTB or DFTB/MM), fragment decomposition of large systems, large scale potential energy landscape exploration with molecular dynamics in ground or excited states, non-adiabatic dynamics. A number of applications are reviewed, focusing on -(i)- the variety of systems that have been studied such as small molecules, large molecules and biomolecules, bare orfunctionalized clusters, supported or embedded systems, and -(ii)- properties and processes, such as vibrational spectroscopy, collisions, fragmentation, thermodynamics or non-adiabatic dynamics. Finally outlines and perspectives are given.

α-Synuclein aggregates in labial salivary glands of idiopathic rapid eye movement sleep behavior disorder

Study Objectives

To assess whether biopsy of the labial minor salivary glands safely detects phosphorylated α-synuclein (pAS) deposits in idiopathic rapid eye movement sleep behavior disorder (IRBD), a condition that precedes the cardinal manifestations of synuclein disorders associated with Lewy-type pathology, namely, Parkinson's disease (PD) and dementia with Lewy bodies (DLB).

Methods

In a prospective study, labial biopsy of the minor salivary glands was performed in 62 patients with IRBD, 13 patients with PD, and 10 patients with DLB who were initially diagnosed with IRBD, and in 33 controls. Aggregates of pAS were assessed by immunohistochemistry using antiserine 129-pAS antibody and the conformation-specific 5G4 antibody.

Results

Sufficient biopsy material containing glandular parenchyma was obtained in all participants. Deposits of pAS were found in 31 of 62 (50%) participants with IRBD, 7 of 13 (54%) with PD, 5 of 10 (50%) with DLB, and in one of the 33 (3%) controls. Participants with IRBD, PD, and DLB with and without pAS immunoreactivity did not differ in demographic and clinical features. Adverse events were lip bruising (9.2%), swelling (6.6%), pain (2.4%), and numbness (1.7%) which were mild and transitory and did not require treatment.

Conclusions

Labial minor salivary glands biopsy proved to be a safe and useful procedure to identify pAS in participants with IRBD, and in participants with PD and DLB initially diagnosed with IRBD. The biopsy provides direct histopathological evidence that IRBD represents a synucleinopathy and that could be useful for histological confirmation of synuclein pathology in PD and DLB.

Closer versus Long Range Interaction Effects on the Non-Arrhenius Behavior of Quasi-Resonant O2 + N2 Collisions

We report in this paper an investigation on energy transfer processes from vibration to vibration and/or translation in thermal and subthermal regimes for the O₂ + N₂ system performed using quantum-classical calculations on different empirical, semiempirical, and ab initio potential energy surfaces. In particular, the paper focuses on the rationalization of the non-Arrhenius behavior (inversion of the temperature dependence) of the quasi-resonant vibration-to-vibration energy transfer transition rate coefficients at threshold. To better understand the microscopic nature of the involved processes, we pushed the calculations to the detail of the related cross sections and analyzed the impact of the medium and long-range components of the interaction on them. Furthermore, the variation with temperature of the dependence of the quasi-resonant rate coefficient on the vibrational energy gap between initial and final vibrational states and the effectiveness of quantum-classical calculations to overcome the limitations of the purely classical treatments were also investigated. These treatments, handled in an open molecular science fashion by chaining data and competencies of the various laboratories using a grid empowered molecular simulator, have allowed a rationalization of the dependence of the computed rate coefficients in terms of the distortion of the O₂-N₂ configuration during the diatom-diatom collisions. A way of relating such distortions to a smooth and continuous progress variable, allowing a proper evolution from both long to closer range formulation of the interaction and from its entrance to exit channel (through the strong interaction region) relaxed graphical representations, is also discussed in the paper.

The role of the long-range tail of the potential in O2 + N2 collisional inelastic vibrational energy transfers

In the study of non-reactive energy transfer between O₂ and N₂ molecules bearing different vibrationally excited states we have faced the problem of selecting a proper formulation of the interaction. To this end we have compared the values of the related observables computed either on a potential energy surface globally fitted to very large ab initio potential energy values [Varga et al., J. Chem. Phys., 2016, 144, 024310] or on two more traditional ones formulated as a combination of an intra- and inter-molecular model component of the interaction (and based on a different combined use of experimental and ab initio information) [Garcia et al., J. Phys. Chem. A, 2016, 120, 5208] in order to enforce an appropriate modelling of the long-range tail of the potential, crucial for the description of inelastic vibrational energy transfer. A detailed graphical analysis of the potential plus a quantitative analysis of the computed opacity functions, of the state-to-state rate coefficients, of the second virial coefficient and of the integral non-reactive cross section allowed us to conclude that the model formulation of the interaction has to be preferred for non-reactive studies of the O₂ + N₂ energy transfer processes in thermal and subthermal regimes.

Assessment of α-synuclein in submandibular glands of patients with idiopathic rapid-eye-movement sleep behaviour disorder: a case-control study

BACKGROUND

The histological feature of Parkinson's disease is the presence of intraneuronal aggregates of phosphorylated α-synuclein (αSyn). In patients with Parkinson's disease, deposits of αSyn are found in the autonomic nerve fibres of the submandibular gland. Since patients with idiopathic rapid-eye-movement sleep behaviour disorder (IRBD) can develop Parkinson's disease and other synucleinopathies, we investigated whether αSyn deposits could also be detected in their submandibular gland nerve fibres.

METHODS

We did a case-control study at the Hospital Clinic de Barcelona (Barcelona, Spain) in patients with polysomnographic-confirmed IRBD, patients with clinically diagnosed Parkinson's disease, and controls matched by age with the IRBD group. The controls were either healthy, had had elective neck surgery in the clinic, or were patients who had died in the clinic and had an autopsy. We did a transcutaneous core needle biopsy of the submandibular gland with ultrasound guidance in patients with IRBD or Parkinson's disease, and healthy controls, and without ultrasound guidance in the other controls. We assessed the presence of αSyn with immunohistochemistry using 129-phosphorylated antiserine monoclonal antibody, and analysed quantitative variables with Kruskall-Wallis tests and qualitative variables with Fisher's exact tests.

FINDINGS

We did our study between July 16, 2014, and May 16, 2015, and recruited 21 patients with IRBD, 24 patients with Parkinson's disease, and 26 controls (seven healthy, 11 patients undergoing neck surgery, and eight autopsies). We obtained submandibular biopsy material containing glandular parenchyma in nine (43%) of 21 patients with IRBD, 12 (50%) of 24 patients with Parkinson's disease, and all (100%) of the 26 controls. αSyn aggregates were detected in nerve fibres of the glandular parenchyma in eight (89%) of nine patients with IRBD and eight (67%) of 12 with Parkinson's disease, but none of the controls. Of the individuals whose biopsy samples did not contain glandular parenchyma, deposits of αSyn were found in extraglandular tissues in an additional three (25%) of 12 patients with IRBD and five (42%) of 12 patients with Parkinson's disease. None of the controls showed αSyn immunoreactivity in extraglandular tissues. Of the 52 participants who had ultrasonography-guided biopsy, 11 (21%) reported mild-to-moderate local pain, and nine (17%) developed a subcutaneous haematoma; however, these adverse events were transient and did not need treatment.

INTERPRETATION

Our findings suggest that, in patients with IRBD, submandibular gland biopsy is a safe procedure for the detection of αSyn aggregates. αSyn detection could be useful for histological confirmation in individuals clinically diagnosed with Parkinson's disease.

FUNDING

Centre for Networked Biomedical Research in Neurodegenerative Disorders (CIBERNED), Barcelona, Spain.

[Introduction of Aedes albopictus in Spain: a new challenge for public health]

INTRODUCTION

A spectacular increase was noticed in the number of consultations for insect bites at the Sant Cugat Primary Care Center (Barcelona, Spain). Subsequent study of the species in the area identified Aedes albopictus.

OBJECTIVE

To analyze consultations for insect bites in this center (1998-2004).

METHODS

A descriptive, cross sectional study with a 7-year retrospective review was performed. A total of 2,760 patients consulted.

RESULTS

A continual increase in the number of consultations for insect bites was detected, reaching 16 consultations per 1,000 inhabitants. The mean age of the patients was 32 years and 62% were women. Seventy-one percent of the bites were located on the extremities and 19% were infected. Sixty-seven percent of the patients received systemic treatment.

CONCLUSIONS

Primary care alerted the town council of the significant increase in consultations for insect bites. Patients consulting for this reason were predominantly young women who frequently received systemic treatment and showed a high percentage of local complications.

Derivación sin visita desde los servicios de urgencias hospitalarios: cuantificación, riesgos y grado de satisfacción

BACKGROUND AND OBJECTIVE

After triage assessment, some hospitals refer emergency department (ED) patients with minor chief complaints to off-site clinics. The potential for 2 different referral models introduced in 2 urban hospitals was assessed, as well as the suitability of this measure.

PATIENTS AND METHOD

After triage assessment, patients with minor complaints were identified. ED from Hospital Clínic of Barcelona (HCB) proposed that these patients should be referred to a hospital affiliated off-site clinic, whereas ED from Hospital Mútua de Terrassa (HMT) tried to refer such patients to their primary care setting. Within a year, we assessed on both ED the following items: number of arrivals, percentage of proposed referrals (PR), percentage of accepted referrals (AR), percentage of carried-out referrals (CR: patients who, once discharged, really attended the other setting), and percentage of returned referrals (RR) to the ED, as well as return reasons, and the percentage of returned patients finally admitted. The degree of patient satisfaction was evaluated by means of a telephone survey.

RESULTS

From both ED, 44,764 arrivals and 7,297 (16.3%) PR were registered. The percentage of AR and CR was 94.3% and 75.3%, respectively. The percentage of PR from HMT was higher (18.7% vs 13.1%; p < 0.001), yet HCB obtained a greater percentage of AR (98.9% vs 92%, p < 0.001) and CR (93.7% vs 65%; p < 0.001). The percentage of RR from both ED was 1.5% (2.8% vs 0.4%; p < 0.001). Among returned patients, 12 of them (0.17% respect to AR) were finally admitted. Only 41% of patients who were found to be eligible for direct discharge would have agreed with being referred to another clinical setting, but after the experience, up to 93% of them said they would go through it again. HMT gave referral information to patients faster than HCB (p < 0.05), but HCB got a better model evaluation (p < 0.01), a greater medical complaint solution (p < 0.05), and generated a smaller number of subsequent consultations (p < 0.05).

CONCLUSIONS

After a rapid triage assessment, a percentage of patients arriving on EDs may be directly and safely discharged and referred to other clinical settings. This is achieved by both proposed models without additional risks for patients. However, patients feel more satisfied with an hospital-affiliated off-site clinic instead of their primary care setting.

[Abdominal aortic injury as a complication of laparoscopic cholecystectomy]

A 58-year-old woman with a history of high blood pressure and cesarean section by median laparotomy underwent elective laparoscopic cholecystectomy under general anesthesia. After initiation of pneumoperitoneum, hemodynamic instability developed (blood pressure 75/40 mm Hg, heart rate 47 beats/min) and resolved after volume replacement and administration of vasoactive drugs. The rest of the procedure was completed without further adverse events. After extubation, the patient was transferred to the anesthetic recovery ward, where she tended to hypotension that was unresponsive to volume replacement, with a hematocrit of 18% and hemoglobin concentration of 6.9 g/dL. Hemoperitoneum was suspected, and an emergency median laparotomy revealed 300 cc of blood in the peritoneal cavity, a large hematoma putting pressure on retroperitoneal structures, and 2 infrarenal aortic lesions (anterior and posterolateral). During the reoperation the patient required multiple transfusions and vasoactive drugs to maintain hemodynamic stability. Recovery in the postanesthetic care unit was uneventful. After transfer to the ward, on the 20th day after surgery she developed septic shock with intraabdominal fluid requiring surgical drainage and admission to the intensive care unit. Abdominal aortic injury during laparoscopic surgery usually occurs upon introduction of trocars for initiating pneumoperitoneum. The technique must be performed correctly and monitored properly to assure early detection of adverse events associated with high mortality.

Photophysical properties of neutral and cationic tetrapyridinoporphyrazines

We describe the synthesis and photophysical properties of a series of neutral and cationic 3,4-tetrapyridinoporphyrazines, potential lead photosensitizers for photodynamic inactivation of bacteria. Tetracationic TPyPzs exist essentially as monomers in aqueous systems, but the presence of trialkylated compounds due to incomplete quaternization of the outer nitrogen atoms induces severe aggregation. The absorption, fluorescence, triplet, and singlet oxygen quantum yields for both the neutral and cationic compounds are comparable to those of the related phthalocyanines.

Diagnostic utility of postmortem fine-needle aspiration cultures

BACKGROUND

Microbiological cultures at autopsy have not proved to be very useful. In life, transthoracic and fine-needle aspirations of other tissues have provided better results. The aim of this prospective study was to assess the diagnostic utility of postmortem cultures obtained by fine-needle aspiration puncture (FNAP) of several tissues when punctures were performed in the immediate postmortem period.

METHODS

Comparative analysis was performed between FNAP cultures and those obtained in life and by conventional autopsy. All adult autopsied patients who died at a general teaching hospital in a 3-year period were included. Clinical data, microbiological cultures before death, and pathologic data from autopsies of all patients were recorded, as were results of FNAP performed after death from the heart, right lower lung, liver, spleen, and other areas suspicious for infection. Cultures from the same sites were made at autopsy. Microorganisms were isolated and defined as infectious agents, colonizers, or contaminants according to standard criteria.

RESULTS

Ninety-two patients (59 men, 33 women) were included in the study; patients had a mean age of 67.7 years. There were five main diagnostic groups: neoplastic (n = 25), digestive (n = 15), respiratory (n = 14), circulatory (n = 10), and infectious diseases (n = 10). Infection was suspected in 47 patients (51.3%). Autopsy was performed 12 hours after death or later in 61% of patients. No significant differences were found in terms of contamination or colonization in relation to time between death and FNAP, time between death and autopsy, or microorganisms isolated. The sensitivity of FNAP and autopsy with respect to the isolation of infective microorganisms was similar (80.9% vs 87%), but FNAP was more specific (66.7% vs 44.4%). Age, sex, time between death and FNAP, clinical diagnosis, cause of death, and antimicrobial therapy did not influence the results significantly. Blood cultures gave the best results (specificity 84.4%) [corrected].

CONCLUSIONS

Fine-needle aspiration puncture performed in the immediate postmortem period adds relevant microbiological information to the clinicopathologic picture and provides higher specificity than autopsy cultures. Blood cultures are especially useful. When difficulties are associated with autopsy examination or in cases of selected clinical conditions, FNAP can be an effective tool for the postmortem diagnosis of infection.

Predictors of mortality in patients with bacteremia: the importance of functional status

OBJECTIVE

To evaluate the influence of functional status on the outcome in older patients with bacteremia.

DESIGN

Prospective study of all episodes of bacteremia that occurred in adults during a 27-month period (January 1991 to March 1993).

SETTING

A 280-bed community hospital.

PARTICIPANTS

During the study period, bacteremia was diagnosed in 242 consecutive patients (incidence of 11.2 bacteremic episodes per 1000 hospital admissions). One hundred twenty-seven of these patients were 65 years of age or older, and 115 were less than age 65.

MEASUREMENTS

On identification of a positive blood culture, data on demographics, clinical findings, and a series of factors frequently cited as predisposing to infection were collected. The patient's functional status was assessed using the Barthel index (a score of < 60 identifies moderately and highly dependent patients).

RESULTS

The overall mortality rate was 14.9% (36 of 242). In the univariate analysis, mortality was associated significantly with age greater than 65 years, nosocomial infection, absence of fever, shock, leukocytosis or leukopenia, inappropriate therapy, more than one underlying disease, immuno-compromised state, and limited functional status. Multiple logistic regression analysis revealed that shock (OR = 27.6, 95% CI 5.7-133), a Barthel score less than 60 (OR = 11.7, 95% CI 3.2-43), nosocomial infection (OR = 6.7, 95% CI 1.8-25.5), absence of fever (OR = 5.2, 95% CI 1.05-26), and immunocompromised state (OR = 15.6, 95% CI 2.4-101.5) were significantly associated with death attributable to bacteremia.

CONCLUSION

The main prognostic factors in a patient with bacteremia were the presence of shock, impaired functional status, immunodeficiency state, acquisition of infection in the hospital, and absence of fever on admission. Age alone did not influence outcome.

[Bacteremia in 13 general hospitals of the province of Barcelona. Prospective study of 1,674 episodes. Group of Microbiologists of the County Hospitals of Catalonia]

BACKGROUND

Clinical and microbiological description of bacteremias seen in 13 regional hospitals of Barcelona.

METHODS

From January to December of 1991 a multicenter prospective study of bacteremia in regional hospitals was performed. The filiation, clinical findings and microbiological results were registered according to a common protocol.

RESULTS

We studied 1674 episodes of bacteremia (13.8 per 1000 admissions). Patients were distributed into 3 groups according to age: under 14: 204 patients, between 14 to 65: 759 and over 65: 711 patients. Men account for 55% and women for 45% of episodes. The bacteremia was hospital-acquired in 24.4% of cases. The most common foci of infection were: urinary tract (32%), respiratory tract (14%), intestinal tract (8%), intravascular catheter (7%), biliary tract (7%) and unknown (10%). The most commonly isolated strains were: Escherichia coli 544 cases, Streptococcus pneumoniae 212, Staphylococcus aureus 139, coagulase negative staphylococi 85, Non-typhoid Salmonella 66, Neisseria meningitidis 63, Pseudomonas sp. 59, Enterococcus sp. 59 and Bacteroides sp. 58. Polimicrobial bacteremia was detected in 83 episodes (5%). Related mortality rate was 9.6% (161 patients).

Predictive factors for invasive disease due to penicillin-resistant Streptococcus pneumoniae: a population-based study

A prospective population-based study was carried out to determine predictive factors associated with penicillin-resistant pneumococcal invasive disease. A total of 374 patients (250 males and 124 females; mean age, 50.3 +/- 27 years) with invasive pneumococcal infection were admitted to one of the five hospitals in El Vallés County (an industrial area with 800,000 inhabitants in the province of Barcelona, Spain) over a period of 5 years. Of the 374 episodes, 21 (5.6%) were due to highly penicillin-resistant pneumococci and 67 (17.9%) to intermediately penicillin-resistant pneumococci. Multivariate analysis showed a statistically significant association between infection with intermediately penicillin-resistant pneumococci and an age of 0-4 years (odds ratio [OR] = 5.3; 95% confidence interval [CI] = 2.2-12.6), the presence of an immunosuppressive underlying disease (OR = 3.0; 95% CI = 1.5-6.0), and the previous use of beta-lactam antibiotics (OR = 2.1; 95% CI = 1.0-4.5). Infection with highly penicillin-resistant pneumococci was associated only with the previous use of beta-lactam antibiotics (OR = 5.9; 95% 95% CI = 2.2-15.8). Highly resistant strains were of serotypes 6, 9, 14, 15, 19, and 23, of which all but serotypes 9 and 15 are included in the newly formulated conjugated vaccine.

Meningococcal meningitis with 'normal' cerebrospinal fluid

A prospective study was made of all patients with normal CSF counts and positive cultures for Neisseria meningitidis diagnosed in "El Vallés" County, Barcelona between January 1987 and December 1990. Meningococcal meningitis was documented in 82 patients, eight of whom (seven children, five boys and two girls with a mean age of 5.6 +/- 3.3 years, and a 69-year-old male patient) had no apparent CSF abnormalities in the initial lumbar puncture. At the time of admission all patients had fever (mean 39.1 degrees C) of 10.8 +/- 5.6 hour duration and petechial rash which had been present for a mean of 3.6 +/- 3.3 hours. Signs of meningeal irritation were not found. A 4-month-old infant with symptoms of circulatory collapse, intracranial hypertension and impairment of consciousness subsequently died of septicemia in 48 hours. Group B N. meningitidis was isolated in six cases (reduced penicillin-susceptibility in two cases) and group C N. meningitidis in the remaining two (reduced penicillin-susceptibility in one case). Patients without pleocytosis did not differ in a statistically significant fashion from the patients with high pleocytosis in the duration of temperature, and petechial rash, leukopenia, positive blood culture and fatal outcome.

Prospective epidemiological study of invasive Haemophilus influenzae disease in adults

The incidence and characteristics of invasive Haemophilus influenzae disease were studied in 43 adult patients admitted to the acute care hospitals in El Vallés County (Barcelona, Spain) between January 1987 and June 1992. The annual incidence of Haemophilus influenzae disease was 1.2 per 100,000 inhabitants. Pneumonia occurred in 24 patients, meningitis in five, intraabdominal infections in three, obstetric infections in two, epiglottitis in two and cellulitis in one. In six patients the source of infection was unknown. Ten (23%) of the infections were hospital acquired. Underlying conditions were diagnosed in 30 (70%) patients. Nontypeable Haemophilus influenzae strains predominated in all adult age groups. Sixty-one percent of type b and 34% of nontypeable strains were ampicillin resistant (p = 0.08). Multiple antibiotic resistance was also high among type b (53%) and nontypeable (18%) strains. The mortality rate was significantly higher in patients with pneumonia, bacteremia from an unidentified focus or shock at presentation.

[Characterization of Haemophilus influenzae's resistance to ampicillin]

BACKGROUND

The resistance of Haemophilus influenzae to ampicillin is nearly always dependent on plasmid-mediated betalactamase production. The betalactamase type most frequently identified was TEM-1; type ROB has occasionally been identified. The presence of plasmid-mediated betalactamase has been studied in H. influenzae strains moderately susceptible or resistant to ampicillin.

METHODS

The test used in the detection of the presence of betalactamase was nitrocefin hydrolysis; the enzyme type was identified by analytic isoelectric focusing; the codifying gene of this betalactamase was identified by hybridisation with a TEM-1 probe labeled with digoxigenine. Strains studied were 110, obtained during the period 1987 to 1989 and isolated from four Hospitals of the Vallés area of Barcelona.

RESULTS

Enzyme production was detected in 105 of 110 strains studied; TEM-1 type betalactamase was identified in 108 and positive hybridisation was obtained in these strains with the TEM-1 probe.

CONCLUSIONS

Nitrocefin hydrolysis is a reliable test for the detection of betalactamase production, although it may be unable to detect it (falses negatives) when the production is low. The only betalactamase type identified was TEM-1. The frequency of the strains with non-enzymatic resistance was 1.8%.

Neisseria meningitidis with reduced sensitivity to penicillin: observations in 10 children

10/84 strains (11.9%) of Neisseria meningitidis isolated from blood and/or cerebrospinal fluid in children 1986-1987 had reduced sensitivity to benzylpenicillin (MICs 0.1-0.4 mg/l). Group C meningococci predominated among these strains. The clinical course was satisfactory in all cases regardless of the antibiotic treatment used, although the time to abatement of fever was prolonged compared to that of children infected with susceptible strains.