Image-guided moderately hypofractionated radiotherapy for localized prostate cancer: a multicentric retrospective study (IPOPROMISE)

BACKGROUND

Moderate hypofractionated radiotherapy is a treatment option for the cure of localized prostate cancer (PCa) patients based on the results of randomized prospective trials, but there is a clinical concern about the relatively short length of follow-up, and real-world results on outcome and toxicity based on cutting-edge techniques are lacking. The objective of this study is to present the long-term results of a large multicentric series.

MATERIALS AND METHODS

We retrospectively evaluated 1325 PCa patients treated with daily volumetric image-guided hypofractionated radiotherapy between 2007 and 2020 in 16 Centers. For survival endpoints, we used Kaplan-Meier survival curves and fitted univariate and multivariable Cox's proportional hazards regression models to study the association between the clinical variables and each survival type.

RESULTS

At the end of the follow-up, 11 patients died from PCa. The 15-year values of cancer-specific survival (CSS) and biochemical relapse-free survival (b-RFS) were 98.5% (95%CI 97.3-99.6%) and 85.5% (95%CI 81.9-89.4%), respectively. The multivariate analysis showed that baseline PSA, Gleason score, and the use of androgen deprivation therapy were significant variables for all the outcomes. Acute gastrointestinal (GI) and genitourinary (GU) toxicities of grade ≥ 2 were 7.0% and 16.98%, respectively. The 15-year late grade ≥ 2 GI and GU toxicities were 5% (95%CI 4-6%) and 6% (95%CI 4-8%), respectively.

CONCLUSION

Real-world long-term results of this multicentric study on cutting-edge techniques for the cure of localized PCa demonstrated an excellent biochemical-free survival rate of 85.5% at 15 years, and very low rates of ≥ G3 late GU and GI toxicity (1.6% and 0.9% respectively), strengthening the results of the available published trials.

Mechanical stimulation devices for mechanobiology studies: a market, literature, and patents review

Significant advancements in various research and technological fields have contributed to remarkable findings on the physiological dynamics of the human body. To more closely mimic the complex physiological environment, research has moved from two-dimensional (2D) culture systems to more sophisticated three-dimensional (3D) dynamic cultures. Unlike bioreactors or microfluidic-based culture models, cells are typically seeded on polymeric substrates or incorporated into 3D constructs which are mechanically stimulated to investigate cell response to mechanical stresses, such as tensile or compressive. This review focuses on the working principles of mechanical stimulation devices currently available on the market or custom-built by research groups or protected by patents and highlights the main features still open to improvement. These are the features which could be focused on to perform, in the future, more reliable and accurate mechanobiology studies.

Graphic abstract

Selective Laser Melting of Ti6Al4V sub-millimetric cellular structures: Prediction of dimensional deviations and mechanical performance

Ti6Al4V sub-millimetric cellular structures arise as promising solutions concerning the progress of conventional orthopedic implants due to its ability to address a combination of mechanical, physical and topological properties. Such ability can improve the interaction between implant materials and surrounding bone leading to long-term successful orthopedic implants. Selective Laser Melting (SLM) capability to produce high quality Ti6Al4V porous implants is in great demand towards orthopedic biomaterials. In this study, Ti6Al4V cellular structures were designed, modeled, SLM produced and characterized targeting orthopedic implants. For that purpose, a set of tools is proposed to overcome SLM limited accuracy to produce porous biomaterials with desired dimensions and mechanical properties. Morphological analyses were performed to evaluate the dimensional deviations noticed between the model CAD and the SLM produced structures. Tensile tests were carried out to estimate the elastic modulus of the Ti6Al4V cellular structures. The present work proposes a design methodology showing the linear correlations found for the dimensions, the porosity and the elastic modulus when comparing the model CAD designs with Ti6Al4V structures by SLM.

Tribological behavior of bioactive multi-material structures targeting orthopedic applications

The following study proposes a multi-material solution in which Ti6Al4V cellular structures produced by Selective Laser Melting are impregnated with bioactive materials (hydroxyapatite or β-tricalcium phosphate) using press and sintering technique. To assess the tribological response of these structures, an alumina plate was used as a counterpart in a flat-on-flat reciprocating sliding test. Ti6Al4V cellular structures impregnated with bioactive materials displayed the highest wear resistance when compared with the unreinforced structures. Among the bioactive structures, Ti6Al4V cellular structures impregnated with βTCP were the ones with higher wear resistance, having the lowest weight loss. Hence, these structures are promising multifunctional solutions for load-bearing applications by gathering suitable mechanical properties (strength and stiffness); bioactive properties and in addition an improved wear performance.

Diet-induced modifications to milk composition have long-term effects on offspring growth in rabbits

It has been clearly demonstrated that the maternal nutritional status during pregnancy and lactation has long-term effects on offspring health. In mammals, milk represents the first maternal support provided to the newborns so that its composition may play a major role in long-term programming. We therefore assessed the effects of maternal high-fat/high-sugar obesogenic (OD) or control (CD) diets on offspring growth and adiposity in the rabbit. Between 7 and 20 wk of age, the BW gain of OD milk-fed rabbits was higher than that of CD milk-fed rabbits ( < 0.05). Body fat mass measurements at 21 wk of age revealed a significant increase in body adiposity as a function of milk ingested during the neonatal period, in both female and male offspring ( < 0.05). A marked weight gain difference was observed according to the milk in both female and male offspring. Moreover, we investigated the composition in major proteins and leptin levels in milk from OD or CD diet-fed dams. Liquid chromatography-mass spectrometry analysis of individual CD skimmed milk samples enabled identification and quantification of the rabbit main milk proteins and of their main phosphorylated isoforms at 2 different stages of lactation (3 and 10 d). Here we show that the OD diet induced a reduction in the whey acidic protein content concomitantly with both an increase in serum albumin and lactoferrin contents and in the phosphorylated isoforms of the main milk proteins. Furthermore, a sharp rise in leptin levels was observed in the milk of OD diet-fed dams on Day 10 of lactation when compared with CD diet animals ( < 0.05). Taken together, these findings provide evidence that lactation is a critical window of development during which exposure to a deleterious diet is highly detrimental to long-term outcomes. Moreover, these insights suggest that it may be possible to prevent at least some of the adverse effects of inadequate maternal nutrition on the long-term metabolic outcomes of the offspring through nutritional interventions applied during the lactation period.

Genetic and nongenetic factors contributing to differences in αS-casein phosphorylation isoforms and other major milk proteins

Relative concentrations of α_S-casein (α_S-CN) phosphorylation isoforms vary considerably among milk of individual cows. We aimed to explore to what extent genetic and other factors contribute to the variation in relative concentrations of α_S-CN phosphorylation isoforms and the phosphorylation degree of α_S-CN defined as the proportion of isoforms with higher degrees of phosphorylation. We also investigated the associations of genetic variants of milk proteins and casein haplotypes with relative concentrations of α_S-CN phosphorylation isoforms and with the phosphorylation degree of α_S-CN in French Montbéliarde cattle from the cheese production area of Franche-Comté. Detailed milk protein composition was determined by liquid chromatography coupled with electrospray ionization mass spectrometry from 531 test-day morning milk samples. Parity, lactation stage, and genetic variation of cows contributed to the phenotypic variation in relative concentrations of individual α_S-CN phosphorylation isoforms and in the phosphorylation degree of α_S-CN. As lactation progressed, we observed a significant increase for relative concentrations of α_S-CN isoforms with higher degrees of phosphorylation (α_S1-CN-9P, α_S2-CN-13P, and α_S2-CN-14P) as well as for the phosphorylation degree of both α_S1-CN and α_S2-CN. Furthermore, the β-CN I variant was associated with a greater proportion of isoforms with lower degrees of phosphorylation (α_S1-CN-8P, α_S2-CN-10P, and α_S2-CN-11P); the β-CN B variant was associated with a greater proportion of isoforms with higher degrees of phosphorylation (α_S1-CN-9P, α_S2-CN-12P to α_S2-CN-14P). The heritability estimates were low to moderate for relative concentrations of α_S2-CN phosphorylation isoforms (0.07 to 0.32), high for relative concentrations of α_S1-CN-8P (0.84) and α_S1-CN-9P (0.56), and moderate for phosphorylation degrees of α_S1-CN (0.37) and α_S2-CN (0.23). Future studies investigating relations between the phosphorylation degree of α_S-CN and technological properties of milk will be beneficial for the dairy industry.

Effect of HAp and β-TCP incorporation on the tribological response of Ti6Al4V biocomposites for implant parts

Titanium and its alloys have been widely used in many engineering areas due to their properties. Despite having a high implant-tissue osseointegration time, Ti6Al4V has been extensively used in prosthesis and articular implants. To promote a faster bone ingrowth and consequently reduce the implant fixation time, the addition of a bioactive phase to form a biocomposite seems to be an excellent solution. Because of their bioactivity and similarity in composition with the human bone, HAp and β-TCP are two of the most widely used calcium phosphates in biomedical applications. To guarantee a strong adhesion of the previous bioactive materials in the implants surface, samples of Ti6Al4V, Ti6Al4V+HAp (10 vol %) and Ti6Al4V+β-TCP (10 vol %) TCP were processed by the hot pressing technique. Tribological tests against Al₂ O_3, lubricated in PBS at 37°C were carried out on a ball-on-flat reciprocating sliding geometry. Loads in the range of 3 N to 30 N were applied and their effect on the friction behavior and wear resistance of the tested materials was evaluated. Values of the coefficient of friction as well as the wear rate tend to increase with the addition of a bioactive phase to the Ti alloy. Micrographs of the worn surfaces showed that abrasion and plastic deformation are the prevailing wear mechanisms in the studied tribosystems. For biocomposites, particularly in the case of Ti6Al4V+HAp, pull-out of bioactive particle clusters has a determinant role on the tribological response, increasing both the friction coefficient and the specific wear rate. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1010-1016, 2018.

Bioactive materials driven primary stability on titanium biocomposites

The Ti6Al4V alloy constitutes an alternative choice to the most common metal-polymer solutions for total hip arthroplasty (THA) due to good biocompatibility, optimal mechanical properties and high load bearing capacity. However, as Ti6Al4V is not bioactive in its conventional form, hydroxyapatite (HAp) and tricalcium phosphate (TCP) have been widely used as coatings of metal prostheses due to their osteogenic properties and ability to form strong bonds with bone tissue. A promising approach consists in creating a bioactive surface metal matrix composite Ti6Al4V+β-TCP or Ti6Al4V+HAp, obtained by hot pressing (HP) of powders. In this work, the tribological performance of Ti6Al4V+β-TCP and Ti6Al4V+HAp composites is studied to evaluate the frictional response and surface damage representative of prosthesis implantation, key factors in bone fixation. Biocomposites with 10vol% β-TCP and 10vol% Hap, as well as base titanium alloy, were prepared by HP with two surface finishing conditions - polished (Ra=0.3-0.5μm) and sandblasted (Ra=2.1-2.5μm) - for tribological testing against bovine cortical bone tissue. The static friction increases with surface roughness (from 0.20 to 0.60), whereas the kinetic regime follows an inverse trend for the biocomposites. In contrast with current knowledge, this study shows that an implant design solution based on Ti6Al4V+β-TCP or Ti6Al4V+HAp biocomposites with polished surfaces results in an improved primary stability of implants, when compared to traditional rough surfaces. Moreover, it is also expected that the secondary stability will improve due to the adhesion between bone and HAp/β-TCP, increasing the overall stability of the implant.

The relationships among bovine αS-casein phosphorylation isoforms suggest different phosphorylation pathways

Casein (CN) phosphorylation is an important posttranslational modification and is one of the key factors responsible for constructing and stabilizing casein micelles. Variation in phosphorylation degree of αS-CN is of great interest because it is suggested to affect milk technological properties. This study aimed to investigate the variation in phosphorylation degree of αS-CN among milk of individual cows and to explore relationships among different phosphorylation isoforms of αS-CN. For this purpose, we analyzed morning milk samples from 529 French Montbéliarde cows using liquid chromatography coupled with electrospray ionization mass spectrometry. We detected 3 new phosphorylation isoforms: αS2-CN-9P, αS2-CN-14P, and αS2-CN-15P in bovine milk, in addition to the known isoforms αS1-CN-8P, αS1-CN-9P, αS2-CN-10P, αS2-CN-11P, αS2-CN-12P, and αS2-CN-13P. The relative concentrations of each αS-CN phosphorylation isoform varied considerably among individual cows. Furthermore, the phenotypic correlations and hierarchical clustering suggest at least 2 regulatory systems for phosphorylation of αS-CN: one responsible for isoforms with lower levels of phosphorylation (αS1-CN-8P, αS2-CN-10P, and αS2-CN-11P), and another responsible for isoforms with higher levels of phosphorylation (αS1-CN-9P, αS2-CN-12P, αS2-CN-13P, and αS2-CN-14P). Identifying all phosphorylation sites of αS2-CN and investigating the genetic background of different αS2-CN phosphorylation isoforms may provide further insight into the phosphorylation mechanism of caseins.

Use of non-echo-planar diffusion-weighted MR imaging for the detection of cholesteatomas in high-risk tympanic retraction pockets

BACKGROUND AND PURPOSE

Non-echo-planar DWI MR imaging (including the HASTE sequence) has been shown to be highly sensitive and specific for large cholesteatomas. The purpose of this study was to determine the diagnostic accuracy of HASTE DWI for the detection of incipient cholesteatoma in high-risk retraction pockets.

MATERIALS AND METHODS

This was a prospective study of 16 patients who underwent MR imaging with HASTE DWI before surgery. Surgeons were not informed of the results, and intraoperative findings were compared against the radiologic diagnosis. Sensitivity, specificity, and positive and negative predictive values were calculated.

RESULTS

Among the 16 retraction pockets, 10 cholesteatomas were diagnosed intraoperatively (62.5%). HASTE showed 90% sensitivity, 100% specificity, 100% positive predictive value, and 85.7% negative predictive value in this group of patients. We found only 1 false-negative finding in an infected cholesteatoma.

CONCLUSIONS

We demonstrate a high correlation between HASTE and surgical findings, suggesting that this technique could be useful for the early detection of primary acquired cholesteatomas arising from retraction pockets and could help to avoid unnecessary surgery.

Modeling of the process of moisture loss during the storage of dried apricots

Moisture content is a reference parameter for dried food because the growth of most microorganisms is inhibited below certain water activity levels. In addition, it has a determining influence on the evolution of important parameters, such as color and flavor, and on other properties and deterioration reactions, such as texture, oxidation processes and nutritional value. During the storage of some dried fruits, moisture is produced due to Maillard reactions and exchanged with the surrounding environment through the packaging. The evolution of dried foods during their shelf life depends on the storage conditions. The aim of this study is to analyze the evolution of the moisture content in dried apricots packaged in different types of containers, namely glass and thermosealed polypropylene trays. The samples were stored at constant temperatures: 5, 15, 25 and 35 °C and were analyzed periodically over a period of 12 months. The sorption isotherms of apricots used in this study were also determined. In order to model how the moisture evolved, an empirical kinetic model was tested. This model considers both water transfer from the fruit and also water production as a result of the Maillard processes. The explained variance was higher than 95% in the samples stored in trays, which were thermosealed with film.

Avaliação do Projecto Integrado para a Prevenção do Abuso Sexual (PIPAS): Estudo preliminar

Neste artigo apresenta-se um programa de prevenção do abuso sexual implementado na Casa Pia de Lisboa e respectiva avaliação e discutem-se, ainda, critérios para a avaliação de programas. No estudo de avaliação utilizou-se um design longitudinal quantitativo, por questionário, com dois momentos, pré e pós-teste, com seis meses de intervalo entre si. Os participantes (N = 188), do 3º ao 6º ano, foram distribuídos aleatoriamente por grupos controlo e experimental, respondendo a um conjunto de questionários considerados adequados para a avaliação das principais competências treinadas no programa. Os grupos não se mostraram diferentes entre o início e o final da intervenção, mas o papel do colégio e o maior número de sessões contribuíram significativamente para o aumento das competências sócio-emocionais dos jovens. Por fim, discutem-se aspectos da aplicação do programa essenciais para a compreensão dos resultados encontrados e fazem-se recomendações sobre práticas de implementação do programa que optimizem a sua eficácia.

The major protein fraction of mouse milk revisited using proven proteomic tools

The PRM/Alf inbred mice exhibit a huge intestinal lengthening. Since milk contains bioactive factors implied in numerous biological processes, one hypothesis is that PRM/Alf milk contains intestinotrophic factors contributing to this remarkable phenotype. A comparison between the milk from PRM/Alf and C57BL/6J (as a control) strains could be helpful in the identification of such factors, including proteins. However, a complete description of the mouse milk major protein fraction is still missing. Hence we adapted a reliable technique to separate and identify the major mouse milk proteins. This approach was achieved through the protein study of milk from C57BL/6J and PWK/Pas strains representative of two Mus musculus subspecies, M. m. domesticus and M. m. musculus respectively. C57BL/6J milk samples were first skimmed and fractionated by reverse phase-HPLC (RP-HPLC). The protein content of each chromatographic peak was analysed by SDS-PAGE and identified by mass spectrometry. This methodological approach allowed characterization of nine major mouse milk proteins: alpha(s1), beta, gamma, epsilon and kappa-caseins, Whey Acidic Protein, lactoferrin, Serum Albumin, Fatty Acid Binding Protein, as well as an alpha(s1)-casein isoform. Then, RP-HPLC patterns of C57BL/6J milk proteins were compared with those obtained starting from the milk of PWK/Pas females. This comparison revealed a protein polymorphism for the alpha(s1)-casein.

[Negative results associated with medication in the emergency department of a hospital]

OBJECTIVE

To find out the prevalence of negative results associated with medication (herein referred to as NRM) in patients attending the emergency department. To classify the results by severity, avoidability and cost, as well as to establish the factors associated with their appearance.

METHOD

Observational, descriptive and cross-sectional study carried out in the emergency department of a tertiary hospital. Patient surveys and emergency department records were used as sources of information. The Dader Method and guidelines from the Third Consensus of Granada were used. Pearson's chi2 test was used to find the association between age, gender and number of drugs and showing signs of NRM. Avoidability was measured using Baena et al's criteria and severity was assessed according to whether or not the patient had been admitted into an observation stall or on to a hospital ward.

RESULTS

24.4% of patients visited the emergency department because of NRM. 16.1% needed to be hospitalised to solve their health issue. 83.9% of all patients with NRM and 77.3% of those hospitalised due to NRM could have been avoided. Statistically, there was a higher prevalence of NRM in patients taking 5 or more different drugs. An estimated euro 14,666,178 was spent on treating avoidable NRM cases in 2003.

CONCLUSIONS

The prevalence of NRM in those who attended the emergency department, the high percentage of avoidability and the cost imposed on the Health Service seem to sufficiently argue a case for the consideration that NRM as a problem which requires the implementation of prevention programmes based on drug-treatment monitoring.

Factors predicting the development of and survival from brain metastasis in transitional cell carcinoma of the bladder

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Background: To date there are no substantial series reported evaluating brain mets in TCC of the bladder. This makes therapeutic evidence-based decision making in this setting extremely difficult. Methods: We followed 1898 pts with TCC of the bladder treated with cystectomy from 1972–2004. Cohort analysis was undertaken for factors predisposing to and of factors that predict survival after brain mets. Results: With median follow-up of 3.6 yrs for this cohort, 545/1898 (28.7%) recurred, 30 (1.6%) with brain mets. Median time to brain mets development was 1.14 yrs, range 0.0710.92 yrs. Median time to first TCC recurrence in brain met pts was 0.86 yrs vs. 1.03 yrs for whole cohort (p=0.25). Median OS from cystectomy 1.36 yrs vs. 3.49 yrs for whole cohort (p<0.0001). Median time from brain mets to death, 3.3 mths range 0–143 mths, skewed by 2 outliers surviving 18 and 143 mths. The following factors were associated with risk of brain mets: younger age (60.2 vs. 66.3 yrs, p=0.01) and LN status at cystectomy (p=0.02) while gender, smoking status, T stage, margin status were not; tumor grade showed a nonsignificant trend to association with brain mets (p=0.14). Pathological parameters did not correlate with duration to development of brain mets. In predicting OS after brain mets, diagnosis age, duration to first recurrence, duration to brain met, original T and N stage and development of multiple vs. brain alone recurrence did not impact overall survival. Patients having any therapy (19/30): surgery (6), radiation (11) or chemotherapy (10) or combination had a better survival that those not treated (p=0.0002). Each modality was associated with at least a trend to better OS: surgery (p=0.03), RT (p=0.09), CT (p=0.08). Conclusions: These results need to be interpreted in the context of selection bias for active treatment, however, selected patients with brain mets from TCC bladder do appear to benefit from active therapy. More work in this area will hopefully lead to more rational therapy and better outcomes.

No significant financial relationships to disclose.

[1st isolation of vancomycin-resistant Enterococcus faecium with the vanB genotype in Argentina: presentation of 2 cases]

We describe the first isolate of van B vancomycin-resistant Enterococcus faecium in Argentina. The strains were recovered from ambulatory patients admitted to a hospital of Buenos Aires city in July 2000. They were not high-risk patients, they had not received previous antibiotic therapy, and they were assisted in different services. MICs for vancomycin were 32 micrograms/ml for both strains, whereas MICs for teicoplanin were 0.12 microgram/ml in case 1 and 0.25 microgram/ml in case 2. PCR was performed to confirm the vanB genotype. The molecular fingerprints of the isolations by PFGE revealed that they were identical. No further VanB strains were isolated in the hospital.

Molecular epidemiology of a multiresistant Pseudomonas aeruginosa outbreak in a paediatric intensive care unit

After isolation of multiresistant (MR) Pseudomonas aeruginosa from 3 hospitalized patients in a paediatric intensive care unit (PICU), a prospective surveillance programme was established to detect infected and/or colonized patients in the hospital. Isolates were examined by means of outer membrane protein (OMP) profiles, serotyping and DNA genomic analysis using pulsed-field gel electrophoresis (PFGE). Fifty-five P. aeruginosa strains were isolated from 23 hospitalized patients during September and October 1997. The median hospital stay before isolation of P. aeruginosa was 8 d. PFGE demonstrated that the same clone infected 14 patients, 4 of whom were not hospitalized in the PICU. Susceptibility patterns and OMP profiles correlated with PFGE results in 37.8% and 36.4% of cases, respectively. Serotype O11 correlated with pattern A in 77% of cases and serotype O4 correlated with unrelated strains in 75% of cases but did not discriminate between outbreak and unrelated isolates. Extensive investigation of cultures failed to identify a reservoir of P. aeruginosa. PFGE was superior to OMP analysis and serotyping for discriminating between strains. The possible mode of acquisition for most of the patients infected with the same clone was cross-contamination.

Outbreak of infection with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a Mexican hospital

Thirty-one strains of Klebsiella pneumoniae (including 10 duplicates) from 21 septicemic pediatric patients (age, <2 months) were studied during a 4-month period (June to October 1996) in which the fatality rate was 62% (13 of 21). These isolates identified by the API 20E system yielded the same biotype. Pulsed-field gel electrophoresis experiments revealed the same clone in 31 strains. The isolates were multidrug-resistant but were still susceptible to ciprofloxacin, imipenem, and cefoxitin. A 135-kb plasmid was harbored in all of the isolates. No transconjugants were obtained that were resistant to ampicillin, cefotaxime, tetracycline, or gentamicin. Isoelectric focusing for beta-lactamases was performed on all strains, and three bands with pIs of 5.4, 7.6, and 8.2 were obtained. Of these, the pI 8.2 beta-lactamase had an extended-spectrum beta-lactamase phenotype. PCR amplification of both TEM- and SHV-type genes was obtained. The sequence analysis of the SHV PCR product indicated a mutation corresponding to the SHV-5 beta-lactamase.

Antimicrobial resistance from enterococci in a pediatric hospital. Plasmids in Enterococcus faecalis isolates with high-level gentamicin and streptomycin resistance

BACKGROUND

Enterococcus spp. is an important nosocomial and community-acquired pathogen. Recent studies have documented the increasing importance of this pathogen in children, particularly in the hospital setting. Our objective in this study was to report the frequency of antimicrobial resistance in enterococci and to determine the characteristics of high-level gentamicin resistance (HLGR) plasmids in Enterococcus faecalis clinical isolates.

METHODS

Two hundred eighty-nine enterococcal isolates were collected during an 18-month period from a tertiary-care pediatric hospital in Mexico City. Isolates were screened for antibiotic resistance, including HLGR. High-level, gentamicin-resistant E. faecalis strains were selected for pulsed-field electrophoresis (PFGE) typing and plasmid analysis. Transferability of resistance markers was carried out using filter matings.

RESULTS

Seventy-six percent of isolates were E. faecalis, 10% were E. avium, 5.2% E. faecium, 5.2% E. raffinossus, 1.38% E. malodoratus, 0.6% E. hirae, and 0.6% E. casseliflavus. Antimicrobial resistance was ampicillin and penicillin 29%, imipenem 17%, and vancomycin 3%, HLGR 5%. The following 15 high-level, gentamicin-resistant isolates were identified: six E. faecalis; four E. avium; three E. faecium, and two E. casseliflavus. Five of the six E. faecalis isolates were different by PFGE and transferred gentamicin and streptomycin resistance on filter membranes. Transfer frequencies ranged from 8.2 x 10(-4) to 6.92 x 10(-5) transconjugants/recipient cell. The plasmid content of donors and transconjugants were homogeneous (one plasmid of 47 kb).

CONCLUSIONS

In this pediatric hospital, antimicrobial resistance in Enterococcus spp. is common. Frequency of high-level, gentamicin-resistant strains is low. Mechanism of HLGR appears to be due to a single plasmid dissemination.