Synthesis and Reactivity of Ruthenium(BINAP)(PPh3).

Ru(BINAP)(PPh3)HCl cleanly reacts with LiCH2TMS to give Ru(BINAP)(PPh3) (1) that has been fully characterized, including by X-ray diffraction (BINAP and TMS stand for (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl and trimethylsilyl respectively). In sharp contrast with other carbonyl-free phosphine complexes of Ru(0), 1 demonstrates a strikingly high thermal stability and no propensity for intramolecular C-H activation (cyclometalation). Yet 1 coordinates acetonitrile and readily exchanges its PPh3 ligand with alkenes and dienes, thus behaving like a "masked" 16-e Ru(0) species. Electron-poor alkenes coordinate more readily than electron-rich ones, which testifies for the nucleophilic character of the Ru(0)-BINAP fragment. While being thermally stable, 1 is highly reactive and is capable of activating C-H and N-H bonds, and even of cleaving an inert N-Et bond. The combination of high reactivity and stability originates from the P,arene-chelation by the BINAP ligand, i.e., the coordinated π-arene stabilizes Ru(0) to prevent cyclometalation, yet it can slide upon substrate coordination, thereby enabling a variety of inert bond activation reactions to occur under mild conditions.

Structural, spectroscopic, luminescence sensing and TD-DFT theoretical studies of a CuP2N-type complex.

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title heteroleptic cuprous complex, [2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl-κ2P,P'](2-phenylpyridine-κN)copper(I) hexafluoridophosphate, rac-[Cu(C44H32P2)(C11H9N)]PF6, conventionally abbreviated rac-[Cu(BINAP)(2-PhPy)]PF6 (I), where BINAP and 2-PhPy represent 2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl and 2-phenylpyridine, respectively, is described. In this complex, the asymmetric unit consists of a hexafluoridophosphate anion and a heteroleptic cuprous complex cation, in which the cuprous centre in a CuP2N coordination triangle is coordinated by two P atoms from the BINAP ligand and by one N atom from the 2-PhPy ligand. Time-dependent density functional theory (TD-DFT) calculations show that the UV-Vis absorption of I should be attributed to ligand-to-ligand charge transfer (LLCT) characteristic excited states. It was also found that the paper-based film of this complex exhibited obvious luminescence light-up sensing for pyridine.

Phosphorous NMR Analysis and Activity of Chiral BINAP-Silver Complexes.

Chiral Ag-atropisomeric ligand species were studied in solution at different temperatures by 31 P-NMR spectroscopy. The analysis and understanding of key parameters in Ag-BINAP complexes were considered in the context of an enantioselective transformation. An efficient silver-catalyzed intramolecular [4+2] cycloaddition reaction of amide-1,6-enyne provided an enantiomerically enriched tricyclic compound using simple reagents and under mild reaction conditions.

Photocatalytic E→Z Contra-Thermodynamic Isomerization of Vinyl Silanes with Lewis Base.

Herein, we disclosed the contra-thermodynamic E→Z isomerization of alkenyl silanes, according to the in situ formation of a chromophoric species, in the presence of rac-BINAP as the catalyst. The reaction carried out in DMSO or CH3 CN under irradiation at 405 nm allowed the interconversion of the E-isomers into the Z-congeners in good to excellent yields and outstanding Z/E selectivities, on 18 examples. Finally, the mechanism of this E→Z isomerization was studied to get insight into the reaction mechanism.

Toward Controlled Syntheses of Diphosphine-Protected Homochiral Gold Nanoclusters through Precursor Engineering.

Controllable syntheses of Au nanoclusters (NCs) with different nuclearities are of great significance due to the kernel-dependent physicochemical properties. Herein, two pairs of enantiomeric Au NCs [Au19(R/S-BINAP)4(PhC≡C)Cl4] (SD/Au19) and [Au11(R/S-BINAP)4(PhC≡C)2]·Cl (SD/Au11), both with atropos (rigid axial chirality) diphosphine BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthalene) as the predominant organic ligands, were controllably synthesized through precursor engineering. The former was obtained by direct reduction of HAuCl4·4H2O, while the latter was obtained by reduction of [Au(SMe2)Cl] instead. Intriguingly, the kernel of SD/Au19 contains an Au7 pentagonal bipyramid capped by two boat-like Au6 rings, which represents another type of Au19 kernel, making SD/Au19 a good candidate for comparative study with other Au19 NCs to get more insight into the distinct structural evolution of phosphine-protected Au NCs. Despite the previous chiroptical studies on some other chiral undecagold NCs, the successful attainment of the X-ray crystal structures for SD/Au11 not only provides a step forward toward better correlating the chiroptical activities with their structural details but also reveals that even the auxiliary protecting ligands also play a nontrivial role in tuning the geometrical structures of the metal NCs. The chiroptical activities of both SD/Au19 and SD/Au11 were found to originate from the chiral ligands and core distortions; the extended π-electron systems in the BINAP ligands have proved to positively contribute to the electronic absorptions and thus disturb the corresponding circular dichroism (CD) responses.

Continued decline in the prevalence of the Clostridioides difficile BI/NAP1/027 strain across the United States Veterans Health Administration.

In 2018, we demonstrated a decreased prevalence of the hypervirulent Clostridioides difficile BI/NAP1/027 strain across the United States (US) Veterans Health Administration (VHA) from 2011 through 2016. The objective of this retrospective study was to update the prevalence of the BI/NAP1/027 strain within the VHA from 2017 through 2020. Patients with positive tests for the presence of toxigenic C. difficile at any Veterans Affairs Medical Center found to also routinely test for BI/NAP1/027 strain presence were included between July 1, 2016 and June 30, 2020. In total, 7490 patients had 8148 positive C. difficile tests that had a corresponding BI/NAP1/027 test. Of those, there were 1031 (12.6%) presumptive positive tests for the BI/NAP1/027 strain. The overall prevalence of BI/NAP1/027 decreased from a high of 15.4% in 2017 to 8.21% in 2020. Statistically significant reductions in rates from 2017 to 2020 occurred in 4 of 9 US Census Bureau regions.

Crystal structure of bis-[(R,R)-1,2-(bi-naph-thyl-phospho-nito)ethane]-dichlorido-iron(II) di-chloro-methane disolvate.

In the title compound (systematic name: bis-{1,2-bis[12,14-dioxa-13-phospha-penta-cyclo-[13.8.0.02,11.03,8.018,23]tricosa-1(15),2(11),3(8),4,6,9,16,18(23),19,21-deca-en-13-yl]ethane}-dichlorido-iron(II) di-chloro-methane disolvate), [FeCl2(C42H28O4P2)2]·2CH2Cl2, the FeII ion lies on a crystallographic twofold rotation axis and is coordinated by four P atoms from two (R,R)-1,2-bis-(bi-naphthyl-phospho-n-ito)ethane (BPE) ligands and two Cl ligands in a distorted cis-FeCl2P4 octa-hedral coordination geometry. In the crystal, weak C-H⋯O and C-H⋯π inter-actions link the mol-ecules into layers lying parallel to (001). A weak intra-molecular C-H⋯O hydrogen bond is also observed. The asymmetric unit contains one CH2Cl2 solvent mol-ecule, which is disordered over two sets of site with refined occupancies in the ratio 0.700 (6):0.300 (6).

Successful management of a Clostridioides difficile ribotype 027 outbreak with a lean intervention bundle.

BACKGROUND: In a 2015 point-prevalence study, Clostridioides difficile 027, a hypervirulent ribotype, was absent from healthcare institutions in Switzerland. In late 2016, we detected an outbreak of C. difficile infection (CDI) with ribotype 027 occurring across several hospitals in the same hospital network. METHODS: The first cases of CDI due to ribotype 027 triggered an outbreak investigation, including whole genome sequencing (WGS) to identify outbreak strains. FINDINGS: Twenty-eight patients with CDI caused by ribotype 027 between December 2016 and December 2017 were identified, out of which 20 were caused by a single clone. Commonalities among these patients were hospitalization in the same room or on the same ward, receiving care from the same healthcare workers, and shared toilet areas. In addition to the epidemiological links suggesting possible transmission pathways between cases, WGS confirmed the clonality of this C. difficile 027 outbreak. The outbreak was contained by isolation precautions, raising awareness among healthcare workers, harmonizing diagnostic algorithms, and switching to a sporicidal agent for environmental disinfection. Of note, neither default gowning and gloving nor hand washing with water and soap were implemented. CONCLUSION: This C. difficile 027 outbreak was recognized belatedly due to lack of screening for this ribotype in some hospitals, and was contained by a swift response with simple infection prevention measures and adapting the laboratory approach. In order to have a better understanding of C. difficile epidemiology, diagnostic approaches should be standardized, CDI declared notifiable, and longitudinal data on prevalent ribotypes collected in countries where this is not established.

A new heteroleptic phosphorescent cuprous complex supported by a BINAP ligand: synthesis, structure, luminescence properties and theoretical analyses.

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The heteroleptic cuprous complex solvate rac-(acetonitrile-κN)(3-aminopyridine-κN)[2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl-κ2P,P']copper(I) hexafluoridophosphate dichloromethane monosolvate, [Cu(C5H6N2)(C2H3N)(C44H32P2)]PF6·CH2Cl2, conventionally abbreviated as [Cu(3-PyNH2)(CH3CN)(BINAP)]PF6·CH2Cl2, (I), where BINAP and 3-PyNH2 represent 2,2'-bis(diphenylphosphanyl)-1,1'-binaphthyl and 3-aminopyridine, respectively, is described. In this complex solvate, the asymmetric unit consists of a cocrystallized dichloromethane molecule, a hexafluoridophosphate anion and a complete racemic heteroleptic cuprous complex cation in which the cuprous centre, in a tetrahedral CuP2N2 coordination, is coordinated by two P atoms from the BINAP ligand, one N atom from the 3-PyNH2 ligand and another N atom from a coordinated acetonitrile molecule. The UV-Vis absorption and photoluminescence properties of this heteroleptic cuprous complex have been studied on polycrystalline powder samples, which had been verified by powder X-ray diffraction before recording the spectra. Time-dependent density functional theory (TD-DFT) calculations and a wavefunction analysis reveal that the orange-yellow phosphorescence emission should originate from intra-ligand (BINAP) charge transfer mixed with a little of the metal-to-ligand charge transfer 3(IL+ML)CT excited state.

Enantioselective liquid-liquid extraction of DL-mandelic acid using chiral diphosphine ligands as extractants.

In order to expand the application range of chiral diphosphine ligands, (S)-BINAP, (S)-SEGPHOS, and (S)-MeO-BIPHEP were employed as extractants to recognize DL-mandelic acid. The results indicated that (S)-SEGPHOS-Cu exhibited considerable ability to recognize DL-mandelic acid with operational enantioselectivity (α) of 2.677. The process of extraction of DL-mandelic acid using (S)-SEGPHOS-Cu as extractant was systematically investigated. Performance factor (pf) was adopted to comprehensively evaluate the extraction. After optimization by response surface methodology (RSM), the optimal extraction condition is temperature of 5.5°C, (S)-SEGPHOS-Cu concentration of 3.0 mmol/L, and pH of 8.0. And the predicted and experimental maximum values of pf were 0.26374 and 0.26839, respectively.

Rhodium catalyzed stereospecific reductive carbocyclization of 1,6-enynes and synthesis of 4'-methyl-6'-substituted aristeromycins.

The need of long-term treatment for chronic HBV, emergence of drug-resistant viruses and inefficiency of currently approved therapies to eliminate covalently closed circular DNA (cccDNA), mandates identification of potent and selective inhibitors of HBV replication with novel mechanisms of action. Entecavir, a carbocyclic guanosine nucleoside analog, is the most potent inhibitor of HBV replication on the market. Moreover, the naturally occurring carbocyclic nucleosides aristeromycin are known for their wide range of antiviral activities. In this research, we have utilized BINAP directed rhodium catalyzed reductive carbocyclization of 1,6-enynes (8a-b) through asymmetric hydrogenation which is an approach, not yet explored in carbocyclic sugar synthesis. Interestingly, we obtained exclusive anti-(9a) and Z-anti (9b) carbocyclic sugars. The new aristeromycin analogs (10a-b) with scaffold combination of entecavir and aristeromycin were then synthesized using the Mitsunobu reaction followed by deprotection.

Asymmetric Synthesis of Diarylmethyl Sulfones by Palladium-Catalyzed Enantioselective Benzylic Substitution: A Remarkable Effect of Water.

A Pd/(R)-BINAP-catalyzed enantioselective benzylic sulfonation of diarylmethyl carbonates with sodium sulfinates proceeds to deliver the corresponding chiral diarylmethyl sulfones in good yields with high enantioselectivity. The reaction occurs in a dynamic kinetic asymmetric transformation (DYKAT) manner and thus provides convergent access to optically active benzylic sulfones from racemic secondary benzylic carbonates. Additionally, the addition of H2 O is found to be critical for high enantioselectivity.

Molecular characterization, toxin detection and resistance testing of human clinical Clostridium difficile isolates from Lebanon.

Clostridium (Clostridioides) difficile is the main cause for nosocomial diarrhoea in industrialised nations. Epidemiologic data on the pathogen's occurrence in other world regions are still scarce. In this context we characterized with phenotypic and molecular genetic methods C. difficile isolates stemming from hospitalised patients with diarrhoea in Lebanon. From 129 stool samples of symptomatic patients at a tertiary care University hospital in Lebanon, a total of 107 C. difficile strains were cultivated and underwent ribotyping, toxin gene detection and antibiotic resistance testing. Ribotype 014 (RT014, 16.8%) predominated, followed by RT002 (9.3%), RT106 (8.4%) and RT070 (6.5%). Binary toxin gene-positive isolates (RT023, RT078 and RT126) were rarely detected and RT027 was absent. Interestingly, within one isolate only the toxin A gene (tcdA) was detected. Multiple-locus variable-number tandem repeat analysis (MLVA) revealed strong strain diversity in most RTs. The isolates were sensitive to metronidazole and vancomycin, and only a small proportion of strains displayed resistance against moxifloxacin, rifampicin, and clarithromycin (5.6%, 1.9%, and 2.8%), respectively. The data indicate that the genetic strain composition of Lebanese strains differs markedly from the situation seen in Europe and North America. Especially the epidemic RTs seen in the latter regions were almost absent in Lebanon. Interestingly, most strains showed almost no resistance to commonly used antibiotics that are suspected to play a major role in the development of C. difficile infection, despite frequent use of these antibiotics in Lebanon. Thus, the role of antimicrobial resistance as a major driving force for infection development remains uncertain in this area.

Prevalence of the Clostridium difficile BI/NAP1/027 strain across the United States Veterans Health Administration.

OBJECTIVES: The increased incidence and severity of Clostridium difficile infection (CDI) are thought to result partly from the emergence of the hypervirulent BI/NAP1/027 strain. Limited recent data are available on the prevalence of BI/NAP1/027 in the United States (US). The objective of this study was to assess the recent prevalence of BI/NAP1/027 within the US Veterans Health Administration (VHA). METHODS: Patients with CDI at any Veterans Affairs Medical Center found to routinely test for the presence of BI/NAP1/027 during the study period were included between 1 June 2011 and 30 June 2016 in this retrospective, observational, nationwide study. RESULTS: In total, 7571 patients had 8224 positive C. difficile tests that had a corresponding BI/NAP1/027 test. Of those, there were 1810 (22.0%) presumptive positive for BI/NAP1/027. The overall prevalence of BI/NAP1/027 decreased from a high of 26.2% in 2013 to 16.9% in 2016. Statistically significant reductions in rates from 2012 to 2016 occurred in seven of nine US Census Bureau regions. CONCLUSIONS: The prevalence of C. difficile with the BI/NAP1/027 strain was 22.0% across the VHA between 2012 and 2016. Further studies are needed to confirm these results and for continued monitoring of the trends in BI/NAP1/027 prevalence.

Synthesis of CuPF6 -(S)-BINAP loaded resin and its enantioselectivity toward phenylalanine enantiomers.

A type of resin-anchored CuPF6 -(S)-BINAP was synthesized and identified. The PS-CuPF6 -(S)-BINAP resin was used to adsorb the phenylalanine enantiomers. The results showed that the adsorption capacity of PS-CuPF6 -(S)-BINAP resin toward L-phenylalanine was higher than that of resin toward D-phenylalanine. PS-CuPF6 -(S)-BINAP resin exhibited good enantioselectivity toward L-phenylalanine and D-phenylalanine. The influence of phenylalanine concentration, pH, adsorption time, and temperature on the enantioselectivity of the resin were investigated. The results showed that the enantioselectivity of the resin increased with increasing the phenylalanine concentration, pH, and adsorption time, while it decreased with an increase in temperature. The causes for these influences are discussed. The highest enantioselectivity (α = 2.81) was obtained when the condition of phenylalanine concentration was 0.05 mmol/mL, pH was 8, adsorption time was 12 h, and temperature 5°C. The desorption test for removing D/L-phenylalanine on PS-CuPF6 -(S)-BINAP resin was also investigated. The desorption ratios of D-phenylalanine and L-phenylalanine at pH of 1 were 95.7% and 94.3%, respectively. This result indicated that the PS-CuPF6 -(S)-BINAP resin could be regenerated by shaking with an acidic solution. The reusability of the PS-CuPF6 -(S)-BINAP resin was also assessed and the resin exhibited considerable reusability.

Antimicrobial susceptibility of Clostridium difficile isolates in Israel.

OBJECTIVES: An increase of Clostridium difficile isolates with reduced susceptibility to various antimicrobial agents has been observed, including isolates that are non-susceptible to antibiotics that are routinely used for treatment of C. difficile, such as vancomycin and metronidazole. We determined the susceptibility rates of C. difficile isolates from hospitals in northern Israel to various antibiotics including tigecycline, which was not previously reported from Israel. METHODS: A total of 81 stool samples were collected from three hospitals in northern Israel from patients with C. difficile infection. Specimens were screened for BI/NAP1/027 ribotype, cultured, and sensitivity tests were performed for vancomycin, metronidazole, moxifloxacin, and tigecycline. Statistical tests were applied for analysing the differences in distribution of resistance between the different antibiotics and between BI/NAP1/027 and resistance of antibiotics. RESULTS: Reduced susceptibility was found among 6/81 isolates for vancomycin, 4/81 for metronidazole, and 17/81 for moxifloxacin. Only 1 isolate had reduced susceptibility to tigecycline, with a mean MIC of 0.05µg/mL. Reduced susceptibility to moxifloxacin was significantly associated with reduced susceptibility to vancomycin (p=0.016) and to metronidazole (p=0.0276), and reduced susceptibility to metronidazole was associated with reduced susceptibility to vancomycin (p=0.0259). Eight of 81 isolates (9.9%) were positive for BI/NAP1/027 ribotype and had significantly higher non-susceptibility rates to moxifloxacin and vancomycin compared with BI/NAP1/027 negative isolates (p<0.0001 and p=0.0113, respectively). CONCLUSIONS: We found higher non-susceptibility rates to vancomycin and metronidazole than most previous studies, while tigecycline resistance rates are very low in northern Israel, rendering it a potential agent for treating CDI.

CRISPR Diversity and Microevolution in Clostridium difficile.

Virulent strains of Clostridium difficile have become a global health problem associated with morbidity and mortality. Traditional typing methods do not provide ideal resolution to track outbreak strains, ascertain genetic diversity between isolates, or monitor the phylogeny of this species on a global basis. Here, we investigate the occurrence and diversity of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated genes (cas) in C. difficile to assess the potential of CRISPR-based phylogeny and high-resolution genotyping. A single Type-IB CRISPR-Cas system was identified in 217 analyzed genomes with cas gene clusters present at conserved chromosomal locations, suggesting vertical evolution of the system, assessing a total of 1,865 CRISPR arrays. The CRISPR arrays, markedly enriched (8.5 arrays/genome) compared with other species, occur both at conserved and variable locations across strains, and thus provide a basis for typing based on locus occurrence and spacer polymorphism. Clustering of strains by array composition correlated with sequence type (ST) analysis. Spacer content and polymorphism within conserved CRISPR arrays revealed phylogenetic relationship across clades and within ST. Spacer polymorphisms of conserved arrays were instrumental for differentiating closely related strains, e.g., ST1/RT027/B1 strains and pathogenicity locus encoding ST3/RT001 strains. CRISPR spacers showed sequence similarity to phage sequences, which is consistent with the native role of CRISPR-Cas as adaptive immune systems in bacteria. Overall, CRISPR-Cas sequences constitute a valuable basis for genotyping of C. difficile isolates, provide insights into the micro-evolutionary events that occur between closely related strains, and reflect the evolutionary trajectory of these genomes.

Diversity of Clostridium difficile PCR ribotypes in Europe: results from the European, multicentre, prospective, biannual, point-prevalence study of Clostridium difficile infection in hospitalised patients with diarrhoea (EUCLID), 2012 and 2013.

Clostridium difficile infection (CDI) is the major cause of infective diarrhoea in healthcare environments. As part of the European, multicentre, prospective, biannual, point-prevalence study of Clostridium difficile infection in hospitalised patients with diarrhoea (EUCLID), the largest C. difficile epidemiological study of its type, PCR ribotype distribution of C. difficile isolates in Europe was investigated. PCR ribotyping was performed on 1,196 C. difficile isolates from diarrhoeal samples sent to the European coordinating laboratory in 2012-13 and 2013 (from two sampling days) by 482 participating hospitals from 19 European countries. A total of 125 ribotypes were identified, of which ribotypes 027 (19%, n =222), 001/072 (11%, n = 134) and 014/020 (10%, n = 119) were the most prevalent. Distinct regional patterns of ribotype distribution were noted. Of 596 isolates from patients with toxin-positive stools (CDI cases), ribotype 027 accounted for 22% (32/144) of infections in cases aged from 18 to less than 65 years, but the prevalence decreased in those aged ≥ 65 years (14% (59/412)) and further decreased in those aged ≥ 81 years (9% (18/195)). The prevalence of ribotype 027 and 176, but not other epidemic strains, was inversely proportional to overall ribotype diversity (R(2) = 0.717). This study highlights an increased diversity of C. difficile ribotypes across Europe compared with previous studies, with considerable intercountry variation in ribotype distribution. Continuous surveillance programmes are necessary to monitor the changing epidemiology of C. difficile.

Fecal Microbiota Transplant: Treatment Options for Clostridium difficile Infection in the Intensive Care Unit.

Clostridium difficile infection (CDI) has steadily increased in incidence since the 1990s, with an associated increase in recurrence and severity, which has in turn lead to more intensive care unit (ICU) admissions. The development of recurrent CDI, in particular, has been associated with increasing patient morbidity and mortality as well as an immense financial burden on the health care system. Recently, fecal microbiota transplantation (FMT) has received much publicity as an effective means of treatment for recurrent CDI. The goal of this review is to provide evidence-based recommendations for the diagnosis and management of CDI, with a particular focus on FMT and its utilization in the ICU.

Descripción clínica y epidemiológica de la infección por Clostridium difficile en población pediátrica / Clinic and epidemiologic description of Clostridium difficile infection in a pediatric population

Background: Clostridium difficile (CUj-associated disease (CDAD) and the role of the hypervirulent strain NAP1 have not been well characterized in Pediatrics. Aims: To describe clinical features of CDAD, and to estimate NAP1 frequency and association with disease severity in Pediatrics. Methods: Descriptive, transversal surveillance of diarrheal episodes in Chilean children, hospitalized between February 2012 and December 2013, positive for CD by molecular diagnosis. Results: A total of 66 episodes of diarrhea with identification of CD occurred thougout the study period in children between 1 month and 19 years of age of which 39% were younger than one year old. CD acquisition was predominantly nosocomial and the most common risk factors were: presence of comorbidities (98.6%), use of antibiotics (93.9%), proton pump inhibitors (84.8%), invasive mechanic ventilation (54.5%), feeding tube (48.5%) and immunosuppression (40.9%). Clinical course was mostly mild, but 12 cases presented an unfavorable course, of which 3/26 occurred in children less than one year. Only one case was positive for NAP1 and had a mild course. Conclusion: Diarrhea with identification of CD was present throughout all pediatric ages, including children less than one year old. Analytical and longitudinal studies are required to better characterize the pathogenic role of CD in this age group. CDAD occurred mostly in patients with risk factors, and the clinical course was predominantly mild.

Introducción: Aún no ha sido bien caracterizada la infección por Clostridium difficile ni el rol de la cepa hipervirulenta NAP1 en pediatría. Objetivos: Describir las características clínicas de la infección por C. difficile, la frecuencia de NAP1 y su asociación con gravedad en población pediátrica. Material y Método: Estudio transversal, descriptivo, de episodios de diarrea con identificación molecular de C. difficile en niños chilenos hospitalizados entre febrero de 2012 y diciembre de 2013. Resultados: Se estudiaron 66 episodios de diarrea por C. difficile, en niños entre 1 mes y 19 años, teniendo 39% menos de un año de edad. La adquisición fue predominantemente nosocomial. Los factores de riesgo más frecuentes fueron: co-morbilidades, uso de antimicrobianos, inhibidores de bomba de protones, ventilación mecánica invasora, sonda de alimentación e inmunosupresión. El curso clínico fue mayoritariamente benigno, con 12 casos de evolución desfavorable incluyendo lactantes bajo un año de edad. Un niño presentó la cepa NAP1, con un curso clínico leve. Discusión: En esta serie, la diarrea con identificación de C. difficile se presentó en niños de todas las edades, incluyendo aquellos bajo un año. Se necesitan estudios analíticos y longitudinales para determinar el rol patógeno en este último grupo etario. La infección afecta a niños con factores de riesgo y es de evolución predominantemente satisfactoria.