Action spectrum for reorientations in bacteriorhodopsin of purple membrane in suspension.

In the present study, the dependency of purple membrane (PM) dielectric responses on the wavelength of light in the range 380-750 nm has showed meaningful changes about the rotation of PM in suspension and about the rotation of bacteriorhodopsin (bR) trimer inside PM, as well. The action spectrum of PM random walk substantiates the existence of two states of bR. One of them (blue edge-state) lies at the blue edge and the other (red edge-state) at the red edge of the visible absorption of bR. The results might bear on correlation of these bands to some bR photocycle intermediates or bR photoproducts. The results implicate the protein-chromophore interactions that eventually underlie protein-lipid interactions. Disrupting the protein-lipid contact during the illumination with light of wavelength in ranges of (410-470 nm) and (610-720 nm) has resulted in emergence of distinct dielectric dispersion at 0.06-0.08 MHz which is comparable to the size of bR trimer or monomer.The work reports on the chromatic adaptation of bR in view of the dielectric spectral parameters of PM. It aimed to explore a correlation seemingly found between the light wavelength and the relaxations of bR trimer inside PM. Changes in rotational diffusion of bR trimer upon blue and red light illumination can influence the three dimensional data storage based on bR, which may implicate bR in bioelectronics.

Promising anticonvulsant N-[(2,4-dichlorophenyl) methyl]-2-(2,4-dioxo-1H-quinazolin-3-yl) acetamide: dose-dependent study and evaluation of anticonvulsant action spectrum in vivo and in silico.

The anticonvulsant spectrum of the original promising anticonvulsant N-[(2,4-dichlorophenyl) methyl]-2-(2,4-dioxo-1H-quinazolin-3-yl) acetamide was studied. The compound had a pronounced anticonvulsant effect, significantly reducing the mortality of mice in models of seizures induced by pentylenetetrazole, picrotoxin, strychnine, and caffeine. In the thiosemicarbazideinduced seizure model, the test compound did not reduce mortality. The obtained results indicated that the mechanism of anticonvulsant action involved GABA-ergic (effective in models of pentylenetetrazole and picrotoxin-induced seizures), glycinergic (efficiency in the strychnine model of paroxysms), and adenosinergic (effectiveness in the model of caffeine induced seizures). Molecular docking of a promising anticonvulsant to anticonvulsant biotargets follow the mechanisms of chemo-induced seizures, namely GABA, glycine, and adenosine receptors type A2A, GABAAT, and BCAT enzymes. The conformity between in vivo and in silico studies results was revealed.

Evaluating disinfection performance of ultraviolet light-emitting diodes against the microalga Tetraselmis sp.: Assay methods, inactivation efficiencies, and action spectrum.

Ultraviolet light-emitting diodes (UV-LEDs) are among the most compact devices and safest technologies in water disinfection systems. However, the validation of different assay methods to evaluate the disinfection performance of different wavelengths (265, 280, 285, and 300 nm) of UV-LEDs toward marine microalgae remains poorly characterized. In this study, several detection assays, namely the culture-based most probable number (MPN) assay, membrane integrity-based vital stain (VS) assay, chlorophyll fluorescence assay, and photochemical efficiency assay, were compared to assess the viability of the marine microalga Tetraselmis sp., with results indicating the MPN assay to be the most sensitive. In addition, this study compared the inactivation kinetics, inactivation efficiency, and energy efficiency of Tetraselmis sp. under different UV wavelengths, as assessed by the VS and MPN assays. The fluence-response curves of Tetraselmis sp. varied with assay and wavelength, with Geeraerd's model fitting all fluence-response microalgal inactivation curves. The results showed a non-significant difference in inactivation efficiency among different wavelengths of UV-LEDs (except for 300 nm) when using the VS assay. On the contrary, significant differences among all wavelengths were observed with respect to inactivation efficiency when using the MPN assay. The wavelength of 265 nm exhibited maximum inactivation efficiency, whereas 285 nm achieved optimal energy efficiency. The UV action spectrum of Tetraselmis sp. exhibited the peak at 265 nm, a finding which matched well with the absorbance spectrum of DNA. The observations from this study provide a theoretical basis and technical support for the application of the emerging UV-LED light sources in the algicidal treatment of marine water.

Action spectrum of phototherapy in hyperbilirubinemic neonates.

BACKGROUND: Phototherapy with blue light matching plasma absorption spectrum of the bilirubin-albumin complex with peak at 460 nm is standard treatment of neonatal hyperbilirubinemia. AIM: To demonstrate clinically the action (efficacy) spectrum of phototherapy in hyperbilirubinemic neonates, through determination of the fraction of total serum bilirubin (TSB) decreased by phototherapy with peak emission wavelengths ≥478 nm (blue-green) compared with that of light of 459/452 nm (blue). METHODS: TSB values were compiled from three earlier trials, in which hyperbilirubinemic neonates were randomized to receive 24 h of either blue-green light (478/490/497 nm) (intervention groups) or blue light (459/452/459 nm) (control groups) with equal irradiance and exposed body surface areas. Ratios (efficacy) between the decrease in TSB between intervention and control groups were calculated and graphed versus peak wavelengths, demonstrating the course of the action spectrum. RESULTS: Calculated efficacy ratios were 1.31, 1.18, and 1.04 for light with peak wavelengths of 478, 490, and 497 nm, respectively. The action spectrum increases from 452/459 to maximum at 478 nm, from where it decreases to 1.18 and finally to 1.04. CONCLUSION: For optimal phototherapeutic treatment, neonates need to be exposed to light with peak wavelength some 20 nm longer than is presently used. IMPACT: The action (efficacy) spectrum of phototherapy for hyperbilirubinemic neonates has its peak wavelength at 478 nm. The peak wavelength of this action spectrum is 20 nm longer than the wavelength presently believed to be most efficient. The peak is also different from the peak found in vitro. For optimal phototherapeutic effect, neonates need to be treated with light of wavelengths some 20 nm longer than are presently used.

Aerosol-based antimicrobial photoinactivation in the lungs: an action spectrum study.

Chronic lung infections are among the most diffused human infections, being often associated with multidrug-resistant bacteria. In this framework, the European project "Light4Lungs" aims at synthesizing and testing an inhalable light source to control lung infections by antimicrobial photoinactivation (aPDI), addressing endogenous photosensitizers only (porphyrins) in the representative case of S. aureus and P. aeruginosa. In the search for the best emission characteristics for the aerosolized light source, this work defines and calculates the photo-killing action spectrum for lung aPDI in the exemplary case of cystic fibrosis. This was obtained by applying a semi-theoretical modelling with Monte Carlo simulations, according to previously published methodology related to stomach infections and applied to the infected trachea, bronchi, bronchioles and alveoli. In each of these regions, the two low and high oxygen concentration cases were considered to account for the variability of in vivo conditions, together with the presence of endogenous porphyrins and other relevant absorbers/diffusers inside the illuminated biofilm/mucous layer. Furthermore, an a priori method to obtain the "best illumination wavelengths" was defined, starting from maximizing porphyrin and light absorption at any depth. The obtained action spectrum is peaked at 394 nm and mostly follows porphyrin extinction coefficient behavior. This is confirmed by the results from the best illumination wavelengths, which reinforces the robustness of our approach. These results can offer important indications for the synthesis of the aerosolized light source and definition of its most effective emission spectrum, suggesting a flexible platform to be considered in further applications.

Solar Ultraviolet Radiation Risk Estimates-A Comparison of Different Action Spectra and Detector Responsivities.

Studies assessing the dose-response relationship for human skin cancer induction by solar ultraviolet radiation (UVR) apply a range of methods to quantify relevant UVR doses, but information about the comparability of these datasets is scarce. We compared biologically weighted effectivities applying the most relevant UVR action spectra in order to test the ability of certain UVR detectors to mimic these biological effects at different times during the day and year. Our calculations were based on solar spectra measured at Dortmund, Germany (51.5° N) and at Townsville, Australia (19.3° S), or computed for latitudes 20° S and 50° N. Convolutions with the CIE action spectra for erythema and non-melanoma skin cancer (NMSC) and with ICNIRP's weighting function showed comparable solar zenith angle (SZA) dependences with little influence of season or latitude. A different SZA dependence was found with Setlow's action spectrum for melanoma induction. Calculations for a number of UVR detector responsivities gave widely discrepant absolute irradiances and doses, which were nevertheless related to those calculated with both CIE spectra by correction factors largely independent of the SZA. Commonly used detectors can thus provide quite accurate estimates of NMSC induction by solar UVR, whereas they may be inadequate to mimic melanoma induction.

Wavelengths and temporal effects on the response of mammalian cells to UV radiation: Limitations of action spectra illustrated by genotoxicity.

All photobiological events depend on the wavelength of the incident radiation. In real-life situations and in the vast majority of laboratory experiments, exposure always involves sources with various emission spectra spreading over a wide wavelength range. Action spectra are often used to describe the efficiency of a process at different wavelengths and to predict the effects of a given light source by summation of the individual effects at each wavelength. However, a full understanding of the biological effects of complex sources requires more than considering these concomitant events at each specific wavelength. Indeed, photons of different energies may not have additive but synergistic or inhibitory effects on photochemical processes and cellular responses. The evolution of a photobiological response with post-irradiation time must also be considered. These two aspects may represent some limitations to the use of action spectra. The present review, focused on mammalian cells, illustrates the concept of action spectrum and discusses its drawbacks using theoretical considerations and examples taken from the literature. Emphasis is placed on genotoxicity for which wavelength effects have been extensively studied. Other effects of UV exposure are also mentioned.

Optimizing spectral quality with quantum dots to enhance crop yield in controlled environments.

Bioregenerative life-support systems (BLSS) involving plants will be required to realize self-sustaining human settlements beyond Earth. To improve plant productivity in BLSS, the quality of the solar spectrum can be modified by lightweight, luminescent films. CuInS2/ZnS quantum dot (QD) films were used to down-convert ultraviolet/blue photons to red emissions centered at 600 and 660 nm, resulting in increased biomass accumulation in red romaine lettuce. All plant growth parameters, except for spectral quality, were uniform across three production environments. Lettuce grown under the 600 and 660 nm-emitting QD films respectively increased edible dry mass (13 and 9%), edible fresh mass (11% each), and total leaf area (8 and 13%) compared with under a control film containing no QDs. Spectral modifications by the luminescent QD films improved photosynthetic efficiency in lettuce and could enhance productivity in greenhouses on Earth, or in space where, further conversion is expected from greater availability of ultraviolet photons.

Action spectrum of the redox state of the plastoquinone pool defines its function in plant acclimation.

The plastoquinone (PQ) pool mediates electron flow and regulates photoacclimation in plants. Here we report the action spectrum of the redox state of the PQ pool in Arabidopsis thaliana, showing that 470-500, 560 or 650-660 nm light favors Photosystem II (PSII) and reduces the PQ pool, whereas 420-440, 520 or 690 nm light favors Photosystem I (PSI) and oxidizes PQ. These data were used to construct a model predicting the redox state of PQ from the spectrum of any polychromatic light source. Moderate reduction of the PQ pool induced transition to light state 2, whereas state 1 required highly oxidized PQ. In low-intensity PSI light, PQ was more oxidized than in darkness and became gradually reduced with light intensity, while weak PSII light strongly reduced PQ. Natural sunlight was found to favor PSI, which enables plants to use the redox state of the PQ pool as a measure of light intensity.

Characteristics and clinical significance of augmentation spectra in solar urticaria.

Solar urticaria has unique spectra, such as inhibition and augmentation. The clinical significance of these spectra, especially augmentation, is not well understood. Reported cases of solar urticaria with augmentation spectra are extremely rare in the published English-language work. The purposes of this study were to evaluate the clinical features of solar urticaria with augmentation spectra and to elucidate the mechanisms and clinical importance of the spectra. We experienced 11 cases (five females, six males; mean age, 40.1 years; range, 1-74) of solar urticaria with augmentation spectra from April 2007 to July 2019. Augmentation spectra were UV-B in three cases, UV-A in two, visible light in four, UV-A and UV-B in one, and UV-A and visible light in one. Augmentation spectra were observed before action spectra in four cases, after in six, and before and after in one. Injection of sera irradiated with action spectra and augmentation spectra in vitro induced stronger immediate reactions than those of only action spectrum-irradiated sera in four of five cases. The results of injection tests suggested that augmentation spectra enhance the production of urticaria-forming factor. Clinically, we observed severe urticarial reactions in four cases, including anaphylaxis in three and moderate urticarial reactions in three. These results suggest that augmentation spectra are not as rare as previously thought and that they are associated with the severity of solar urticaria. Therefore, phototesting for both augmentation and action spectra should be performed to provide appropriate guidance for patients with solar urticaria.

Light action spectrum on oxidative stress and mitochondrial damage in A2E-loaded retinal pigment epithelium cells.

AIMS: Blue light is an identified risk factor for age-related macular degeneration (AMD). We investigated oxidative stress markers and mitochondrial changes in A2E-loaded retinal pigment epithelium cells under the blue-green part of the solar spectrum that reaches the retina to better understand the mechanisms underlying light-elicited toxicity. RESULTS: Primary retinal pigment epithelium cells were loaded with a retinal photosensitizer, AE2, to mimic aging. Using a custom-made illumination device that delivers 10 nm-wide light bands, we demonstrated that A2E-loaded RPE cells generated high levels of both hydrogen peroxide (H2O2) and superoxide anion (O2•-) when exposed to blue-violet light. In addition, they exhibited perinuclear clustering of mitochondria with a decrease of both their mitochondrial membrane potential and their respiratory activities. The increase of oxidative stress resulted in increased levels of the oxidized form of glutathione and decreased superoxide dismutase (SOD) and catalase activities. Furthermore, mRNA expression levels of the main antioxidant enzymes (SOD2, catalase, and GPX1) also decreased. CONCLUSIONS: Using an innovative illumination device, we measured the precise action spectrum of the oxidative stress mechanisms on A2E-loaded retinal pigment epithelium cells. We defined 415-455 nm blue-violet light, within the solar spectrum reaching the retina, to be the spectral band that generates the highest amount of reactive oxygen species and produces the highest level of mitochondrial dysfunction, explaining its toxic effect. This study further highlights the need to filter these wavelengths from the eyes of AMD patients.

Prevention of photosensitivity with action spectrum adjusted protection for erythropoietic protoporphyria.

Erythropoietic protoporphyria is a genetic disease characterized by sensitivity to sunlight caused by the accumulation of protoporphyrin IX. Photoprotection against ultraviolet A and visible light is necessary for erythropoietic porphyria patients because the absorption spectrum of protoporphyrin IX lies in both ultraviolet A and visible light region. We developed a novel index, in vitro porphyrin protection factor, based on the protoporphyrin IX absorbance spectrum. We also selected appropriate photoprotective products designed according to protoporphyrin IX absorbance. The porphyrin protection factors of a combination of make-up base with a powder as well as with a liquid foundation were significantly higher than those of a conventional sunscreen product, even at a small application dose. An in-use test carried out for 6 months showed that the efficacy of these products was 78.3%, and no adverse reactions were observed. Male subjects preferred liquid foundation, whereas all female subjects used powder foundation. The preference of the subjects could lead to the long-term use of the tested products. In conclusion, this study provided a new approach to improve photoprotection in erythropoietic protoporphyria patients.

Action Spectrum of Photoinhibition in the Diatom Phaeodactylum tricornutum.

Light-dependent electron transfer is necessary for photosynthesis, but light also damages PSII. Light-induced damage to PSII is called photoinhibition, and the damaging reactions of photoinhibition are still under debate. Diatoms possess an exotic combination of light-harvesting pigments, Chls a/c and fucoxanthin, making them an interesting platform for studying the photoreceptors of photoinhibition. We first confirmed the direct proportionality of photoinhibition to the photon flux density of incident light in the diatom Phaeodactylum tricornutum. Phaeodactylum is known for its efficient non-photochemical quenching, and the effect of this photoprotective mechanism on photoinhibition was tested. Photoinhibition proceeded essentially at the same rate in blue-light-grown Phaeodactylum cells that are capable of non-photochemical quenching and in red-light-grown, non-photochemical quenching-deficient cells. To obtain more insight into how the pigment composition of diatoms affects photoinhibition, we measured the action spectrum of photoinhibition in Phaeodactylum. In visible light, the action spectrum resembled the absorption spectrum of Phaeodactylum, and UV radiation caused much more photoinhibition than visible light. Comparison of the action spectrum of photoinhibition with the absorption spectrum and the excitation spectrum of 77 K PSII fluorescence emission confirmed that photosynthetic pigments are involved in photoinhibition, but the photoinhibitory efficiency of red light is weak, suggesting that the role of light-harvesting pigments as light receptors of photoinhibition is secondary. Finally, we compared photoinhibition in Phaeodactylum with that in other photosynthetic organisms, and our data indicate that the PSII reaction centers of Phaeodactylum are not particularly well protected against the primary damage of photoinhibition.

Manejo de la vaginosis bacteriana con cloruro de decualinio / No disponible

No disponible

The spectrum and outcome of paediatric traumatic brain injury in KwaZulu-Natal Province, South Africa has not changed over the last two decades

Objectives. This retrospective review of a prospectively entered and maintained hybrid electronic trauma registry was intended to develop a comprehensive overview of traumatic brain injury (TBI) in children and adolescents and to compare it with previous audits from our local environment and from other developing world centres. All TBI patients admitted to hospital were included in this study. We reviewed the age, gender, outcomes, radiological findings and treatment of the patients.Methods. All patients aged ≤18 years old who were admitted by the Pietermaritzburg Metropolitan Trauma Service (PMTS) with TBI between December 2012 and December 2016 were included in this audit. Results. During the 4-year period under review, a total of 563 children and adolescents were treated for TBI by the PMTS. The median age was 6.4 years and 29% (n=165) were females. The mechanism of TBI was blunt trauma in 96% (n=544) of cases, with 4% (n=19) suffering penetrating trauma. The penetrating mechanisms included impalement by a cow horn and miscellaneous injuries due to saws, axes, barbed wire, spades, stones and knives. The blunt mechanisms included falls (n=102), assaults (n=108), collapse of a building (n=28), bicycle-related injury (n=14), falling off a moving vehicle (n=280), motor vehicle accident (MVA; n=59), pedestrian vehicle accident (PVA; n=183) and animal-related injuries (n=8). There were 454 (80%) mild, 67 (12%) moderate and 42 (7%) severe cases of TBI. A total of 48 patients were admitted to the intensive care unit and 23 were admitted to the high care unit. Nine patients died. All the deaths were in the MVA and PVA group. The spectrum of TBI as diagnosed on computed tomography scans was nonspecific cerebral contusion (n=92), depressed skull fracture (n=70), sub-arachnoid haemorrhage (n=60), extradural haemorrhage (n=41), intracerebral haemorrhage (n=19), free air (n=19), subdural haemorrhage (n=13), intraventricular haemorrhage (n=9). A total of 62 (11%) patients required surgery.Conclusion. There is a significant burden of paediatric TBI in Pietermaritzburg. The majority of TBI was related to blunt trauma and assaults were very common. Although the short-term outcomes are good, the long-term consequences are poorly understood. Injury prevention programmes are needed to help reduce this burden of disease and a nationwide trauma registry is long overdue

Erythema action spectrum of topical 8-methoxypsoralen-sensitized skin re-evaluated: implications for routine clinical practice.

BACKGROUND: Published methodology used to determine psoralen plus ultraviolet A (PUVA) erythemal action spectrum does not reflect current clinical practice for psoralen sensitization. We re-evaluated the PUVA action spectrum using aqueous 8-methoxypsoralen (8-MOP) 2·6 mg L(-1) as used routinely in current clinical practice. OBJECTIVES: To determine the UVA erythema action spectrum of topical 8-MOP-sensitized normal skin. METHODS: Twenty healthy volunteers with skin phototypes I-V were recruited. Forearms were psoralen-sensitized at 37 °C for 10 min. Six UVA irradiations at 10-nm intervals between 325 and 375 nm were randomly allocated to forearm sites and were applied using a 10-nm bandwidth irradiation monochromator. The visual minimal phototoxic dose (MPD) was recorded on each site at 96 h. RESULTS: Volunteer Boston phototypes were: I, n = 2; II, n = 6; III, n = 6; IV, n = 5 and V, n = 1. The mean MPD (J cm(-2) ) for all subjects at each wavelength was as follows: 325 nm, 0·64 (SD 0·37); 335 nm, 0·80 (SD 0·58); 345 nm, 0·96 (SD 0·55); 355 nm, 1·50 (SD 0·85); 365 nm, 2·19 (SD 0·90); and 375 nm, 2·89 (SD 1·06). Therefore, the relative sensitization at each wavelength (erythemal action spectrum) was: 1, 0·83, 0·67, 0·43, 0·29 and 0·22. There were significant differences between the PUVA erythemal effectiveness at different wavelengths but none between skin types. CONCLUSIONS: This study has established the erythemal action spectrum for bath/soak PUVA therapy as is currently performed. In all volunteers, the peak sensitivity was at 325 nm. All volunteers showed a similar trend across the wavelengths studied irrespective of skin type. The determination of the action spectrum for PUVA-induced erythema is important as it permits reliable estimates of erythemal efficacy of any UVA source where the emission spectrum of the lamp is known or can be measured.

Action spectrum for photobleaching of human lenses by short wavelength visible irradiation.

PURPOSE: Cataract is the world-leading cause of blindness. In search for a new treatment of cataract we have found that the yellow discolouration of aged human lenses can be photobleached using a non-invasive, infra-red, femtosecond laser treatment. These results were presented in an earlier PlosOne publication. The objective of the study was to characterize the single-photon photobleaching action spectrum of the aged human lens in vitro. METHODS: Ninety-one human donor lenses were irradiated with continuous wave laser light at 375, 405, 420, 445, 457 or 473 nm. Photobleaching was monitored by photography and transmission measurements. RESULTS: The action spectrum peaked at 420 nm followed by, in order of decreasing effect, 445, 457, 473, 405 and 375 nm. Younger and less absorbent lenses showed smaller changes than older and more absorbent lenses. There was a dose-dependent increase in lens transmission with increasing laser irradiation. CONCLUSIONS: For a 75 year old lens an effect corresponding to elimination of 15 years or more of optical ageing was obtained. This study of the spectral characteristics and intensity needed to bleach the human lens with single-photon laser effects found an action-spectrum peak at 420 nm tailing gradually off toward longer wavelengths and more steeply toward shorter wavelengths. The results may be used to guide experiments with two-photon bleaching.

Coledocolitiasis y colangitis como complicación del uso de ceftriaxona en niños: reporte de caso / Choledocholithiasis and cholangitis as a complication of ceftriaxone in children: a case report

La ceftriaxona es ampliamente usada en pediatría debido a su espectro de acción, larga vida media y buena penetración en los sitios donde se asientan las infecciones más frecuentes. Es bien tolerada, aunque, con frecuencia, en niños que la reciben, se presenta barro biliar y pseudocolelitiasis. Esto se ve favorecido porque cerca del 40% del fármaco es eliminado por la bilis sin modificaciones, donde se comporta como un anión con alta afinidad por las sales de calcio. Resumen La mayoría de los casos cursan asintomáticos o mínimamente sintomáticos, y de resolución espontánea solo al suspender el uso del fármaco. Se presenta el caso de una niña de 4 años que recibe ceftriaxona durante 14 días por sinusitis, desarrollando al quinto día cálculos en la vesícula biliar que crecen hasta 11 mm y tardan 55 días en desaparecer; el día 34, presenta colecistitis, colangitis y coledocolitiasis que requieren manejo hospitalario.

Ceftriaxone is widely used in children because it has a great spectrum, long half-life and good penetration. Is generally well tolerated, although in children who receive the drug, it often presented pseudocolelitiasis and biliary sludge. This is favored because about 40% of the drug is eliminated unchanged in bile where it behaves as an anion with high affinity for calcium salts. Most cases present as asymptomatic or minimally symptomatic and spontaneous resolution, only when the drug is no longer taken. A case of a 4 year old girl who received ceftriaxone for 14 days for sinusitis and on day 5 develops gall bladder stones that grow to 11 mm and last 55 days to go away, the day 34 presents cholecystitis, cholangitis and choledocholithiasis requiring medical management to resolution.

Resistencia a los antibióticos en Escherichia coli con beta-lactamasas de espectro extendido en un hospital de la Orinoquia colombiana / Antimicrobial resistance of Escherichia coli with extended spectrum beta -lactamase in a hospital at the Colombian Orinoquia

Objetivo. Analizar la resistencia de Escherichia coli a los antibióticos de acuerdo con la presencia de beta-lactamasas de espectro extendido (BLEE). Materiales y métodos. Estudio descriptivo y de corte transversal, en el Hospital Departamental de Villavicencio, centro de atención de mediana y alta complejidad. La población de estudio fueron los pacientes con cultivos positivos para E. coli. La variable de estudio fue la resistencia a ceftazidima, cefotaxima y clavulanato. Se confirmó la presencia de BLEE y la resistencia a otros antibióticos. Resultados. Se tamizaron 29.451 estudios de microbiología, de los cuales 26,7 % fueron positivos. Se identificaron 77,6 % como Gram negativos y 2.551 (41,8 %) como E. coli. De los cultivos, 65,1 % se obtuvieron de orina; 9,5 % fueron resistentes a ceftazidima y 8,7 % a cefotaxime. En los aislamientos de orina, la resistencia de E. coli a ceftazidima fue de 6,5 %, mientras que, en aspirados traqueales, fue de 35,0 % (OR=7,98; p<0,05). Se hicieron 315 pruebas confirmatorias para BLEE con equipo Vitek® y 506 con AutoScan®. La mayor cantidad de muestras se obtuvieron de la consulta externa (34,0 %) y, aunque allí se encontró un número significativo de BLEE (6,9 %), hubo mayor resistencia en la unidad neonatal (16,9 %). La resistencia a ampicilina, cefalotina, ciprofloxacina, gentamicina y trimetoprim-sulfametoxazol, fue alta. El 7,1 % de las pruebas confirmatorias con clavulanato fueron positivas para BLEE. Conclusiones. El estudio demostró una frecuencia de 7,1 % de BLEE en esta institución. Hubo servicios con mayor riesgo, como el de neonatos, aunque el fenómeno no se limitaba al ambiente hospitalario. También, se encontró un pequeño porcentaje que fue resistente a carbapenem.

Objective: To analyze antimicrobial resistance of Escherichia coli according to the presence of extended spectrum beta-lactamase. Design: A cross sectional descriptive study. Setting: Hospital Departamental de Villavicencio, a State center of second and tertiary care. Study population: Positive cultures for E. coli were analyzed between September 2005 and November 2009. Interventions: None. Study variable: Ceftazidime and cefotaxime resistance with and without clavulanate. Outcomes: Confirmation of ESBL test and resistance to other antimicrobials. Results: From the 29,451 microbiological samples that were screened, 26.7% were positive. 77.6% were identified as Gram negative and 2,551 (41.8%) were typified as E. coli. 65.1% isolations were from urine samples and 9.5 and 8.7% of them were resistant to ceftazidime and cefotaxime, respectively. 6.5% of urine samples were resistant to ceftazidime, but it raised to 35% for tracheal aspirate (OR 7.98 p<0.05). Three hundred and fifteen confirmatory tests for ESBL were performed with Vitek® and 506 with AutoScan®. Most samples were ambulatory patients (34.0%) and a significant number of them were positive for ESBL (6.9%), but it was higher at the newborn ward (16.9%). Resistance was high for antimicrobials commonly used for infections by this microorganism such as ampicillin, cephalothin, ciprofloxacin, gentamycin and trimethoprim-sulfamethoxazole. Confirmatory ESBL test was 7.1%. Conclusions: The study demonstrates a 7.1% frequency of ESBL at this hospital but the samples from newborn ward showed a higher frequency of ESBL; nevertheless, the issue is not restricted to hospitalized patients. We also found a small number of isolations resistant to carbapenem.

Epidemiología molecular de pseudomonas aeruginosa resistente a ß-lactámicos de amplio espectro en el Hospital San Jerónimo De Montería / Molecular epidemiolgy of broad-spectrum ß-lactams resistant Pseudomonasaeruginosa in Hospital San Jerónimo, Montería

Pseudomonas aeruginosa ha emergido como uno de los principales patógenos hospitalarios causantes de infecciones graves y productores de β -lactamasas de espectro extendido (BLEE) inusuales, como PER- 1, OXA y carbapenemasas. Objetivo. Caracterizar los aislamientos de P. aeruginosa resistentes a -β -lactámicos de amplio espectro por investigación de los genotipos por rep- PCR y su diseminación en este hospital. Métodos. Se obtuvieron 26 aislamientos clínicos de P. aeruginosaresistentes a β -lact´micos de amplio espectro del Hospital San Jerónimo de enero a agosto del 2002. La resistencia a los β -lact´micos de amplio espectro se estableció con el sistema MicroScan® ESBL plusTM. Se utilizó la técnica de rep- PCR para la tipificación molecular de los microorganismos. Resultados. Los aislamientos mostraron resistencia a la fluoroquinolona ciprofloxacina (15/26, 57,6%) y aminoglucósidos, como gentamicina (14/ 26, 53,8%) y amikacina (9/26, 34,6%). También se observó resistencia a meropenem e imipenem (3/ 26, 11,5%). La tipificación molecular por rep-PCR mostró dos clones A y B de 15 y 3 aislamientos, respectivamente y 8 aislamientos no relacionados. El clon A con 15 aislamientos incluía dos subclones idénticos de 8 y 2 aislamientos, y 5 aislamientos estrechamente relacionadas. El clon B incluyó 3 aislamientos estrechamente relacionados con similaridad mayor del 90% Conclusiones. La relación de los fenotipos de resistencia expresados por estos aislamientos, posiblemente, indique la existencia de plásmidos de resistencia causantes de la infección hospitalaria en este hospital y responsables de codificar la resistencia a β-lact´micos de amplio espectro. Asimismo, el análisis molecular por rep-PCR mostró la diseminación de dos clones de P. aeruginosa en el hospital, de los cuales el clon A presentó aislamientos idénticos diseminados en diferentes servicios de la institución, lo que sugiere una transmisión horizontal.

Pseudomonas aeruginosa has emergence as nosocomial pathogen mean causing several illness and producer of extended-spectrum β-lactamases (ESBL) unusual as PER-1, OXA and carbapenemases. Objetives Characterized isolates of broadspectrum β -lactams resistant P. aeruginosa by research of genotype rep-PCR and spread in this hospital. Methods: 26 clinical isolates of broadspectrum β-lactams resistant P. aeruginosa were obtained from Hospital San Jeronimo (HSJ), between January and August 2002. Broadspectrum β-lactams resistant was established with system MicroScan® ESBL plusTM (Dade Inc). Assays by rep-PCR were utilized for molecular typing of microorganisms. Results: Those isolates showed resistance to fluoroquinolone as ciprofloxacin (15/26, 57.6%) and aminoglicosides as gentamicin (14/26, 53.8%) and amikacin (9/26, 34.6%). Also showed resistance to meropenem and imipenem (3/26, 11.5%). Molecular typing by rep-PCR showed 2 clusters of 15 and 3 strains, and 8 strains unrelationed. Cluster of 15 strains included two clons of 8 and 2 strains, and 5 strains relationed. Cluster of 3 strains showed isolates relationed. Conclusions: Relation of resistance phenotypic expressed for this isolates indicating possibly the existance resistence plasmids causing of nosocomial infections in this hospital and responsible encoding broad-spectrum β-lactams resistant, moreover molecular assays by rep-PCR showed spread of 14 cluster of P. aeruginosa in HSJ, the clusters 1, 3 y 6 showed the biggest number of isolates, the remained clusters corresponded to single isolates that suggest an horizontal transmission.