Extended-spectrum TEM- and SHV- Type beta-lactamase-producing Klebsiella pneumoniae strains causing Outbreaks in Intensive Care Units in Italy.

The aim of the present study was to investigate the production of extended-spectrum beta-lactamases (ESbetaLs) and the epidemiological correlations in a total of 107 Klebsiella pneumoniae strains resistant to third- and fourth-generation cephalosporins. The strains were collected from patients in four intensive care units (3 neonatal and 1 general) in three hospitals in Italy between March 1996 and July 1997. All strains were found to produce ESbetaLs. Phenotypic (antibiotyping and ESbetaL patterns) and genotypic (plasmid profile and pulsed-field gel electrophoresis) analyses showed that a single strain had been responsible for each outbreak in each of the four intensive care units. Isoelectric focusing, activity on substrates and gene sequencing showed that the strains produced SHV-5, SHV-2a, SHV-12 and TEM-52 beta-lactamases. This is not only the first time that ESbetaL-producing Klebsiella pneumoniae strains have been reported as causing epidemics in Italian hospitals, it is also, to the best of our knowledge, the first time that an outbreak caused by a TEM-52 ESbetaL-producing Klebsiella pneumoniae strain has been reported. The data presented here illustrate the complexity of determining the epidemiological pattern of ESbetaL producers in large hospitals that do not have an ESbetaL-monitoring program

CORESHINE : a tracer of grain growth in dark clouds

Scattering by dust grains in the interstellar medium is a well-known phenomenon in the optical and near-infrared domains. We serendipitously discovered the effect of scattering in the mid-infrared in the dark cloud L183, and nicknamed the effect "coreshine". We investigated over 200 sources from both the Spitzer Archive and a new warm Spitzer mission program to check the frequency of the phenomenon and found over 50% of the cases to be positive, which is possibly only a lower limit. We see differences depending on the Galactic regions we investigate. Taurus is a highly successful target while the Galactic plane is too bright to let coreshine appear in emission. We present coreshine as a large grain tracer and we discuss its absence in the Gum/Vela region, which would indicate that big grains have been recently destroyed by the supernova blast wave. Finally, we discuss the prospect for future coreshine searches from archives, present and future instruments

Usefulness of Microscan System panels with EUCAST clinical breakpoints to evaluate the antimicrobial susceptibility of ß-lactamase producing- Gram negative isolates

The study aimed to evaluate the ability of NBC45, NBC46 and NB40 Microscan (MS) panels, updated to 2010 EUCAST breakpoints, to identify at species level and to correctly define the susceptibility to ß-lactams of 61 ß-lactamases (BLs) producing Gram-negative isolates. A collection of 73 fully identified strains was analyzed: 21 Klebsiella spp., 17 E. coli, 15 P. mirabilis, 9 A. baumannii (Ab), 7 P. aeruginosa and 4 Enterobacter spp.. 61/73 were BLs and/or carbapenemases producers: 15 were CTX-M-1/-2/-14/-15 positive, and among them two were also VIM-1 positive. Four were TEM-52/-92, 3 PER-1, 2 SHV-12/-18 and 6 CMY-16 producers, while 11 were KPC-2/-3, 9 OXA-51/-58/-23, 8 VIM-1 and 2 IMP-13 positive. One K. oxytoca K-1 iper-producer, 11 non-BL producers/ATCC control strains and a OprD2 porin lacking P. aeruginosa were also included. All isolates were identified by Api-20E and VITEK-2 System and antibiotic susceptibilities were obtained by broth microdilution method. Resistance genes were identified by PCR and sequencing. All 73 isolates were correctly identified and a complete agreement for susceptibility patterns was observed for both ATCC control strains and non-BL clinical isolates. MS failed to detect a BL/Extended-Spectrum-ß-Lactamase (ESâL) production in 5/61 cases: any ESßL alert was detected using NBC46 panel for 3/15 CTX-M positive strains and 2 VIM-1/CTX-M-15 producing K. pneumoniae isolates. Intermediate resistance to cefoxitin (MIC 16 mg/L), susceptibility to cefepime (MIC 8 mg/L for ertapenem (ETP), according to previously results. All VIM-1 producers resulted intermediate/resistant to imipenem (IP) and meropenem (MP); decreased MIC values were observed in 2/8 cases. Carbapenem MICs >8 mg/L were detected for IP-13 P. aeruginosa producers; 6/9 OXA carbapenemases- producing Ab showed IP MIC >8 mg/L and 3/6 MP MIC >8 mg/L. 3/9 Ab OXA-58/-51 producers, tested using NB40 panel, were intermediate or resistant to doripenem and meropenem. Regarding the detection of BLs overall agreement between MS and reference methods was 91.9%. Carbapenems MIC values resulted a fold lower than previously determined. Nevertheless using 2010 EUCAST breakpoints for ETP, MP and IP was possible to detect all carbapenemases- producers. MS System represents a useful tool to perform identification of BL- producing Gram negative bacteria

Tracing micron-sized grains in molecular clouds with coreshine

Recently discovered scattered light at 3-5 µm from low-mass cores (so-called "coreshine") reveals the presence of grains around 1 µm. But only a fraction of the cores investigated so far show the effect. We derive a simple limit for detecting scattered light from a low-mass core can be derived. The extinction by the core prohibits detection in bright parts of the Galactic plane, the phase function favors the off-plane detection near the Galactic center and to some extent near the Galactic anti-center. Our 3D radiative transfer calculations for the core L260 show that also the K band is capable of probing coreshine, and that the shape of the Ks band surface brightness profile limits the largest grains to sizes of to 1-1.5 µm. For the core L1506C showing coreshine and strong depletion, but low density and turbulence our grain growth calculations and radiative transfer modeling show detectable coreshine at 3.6 µm only when we increase the core density and the turbulence above what is currently observed. The grains could be part of primitive omnipresent large grain population becoming visible in the densest part of the ISM, could have been grown under the turbulent dense conditions of former cores, or in L1506C itself. In the later case, L1506C must have passed through a period of larger density and/or stronger turbulence. This would be consistent with the surprisingly strong depletion usually attributed to high column densities, and with the large-scale outward motion of the core envelope observed today

Growth in glucose-based medium and exposure to subinhibitory concentrations of imipenem induce biofilm formation in a multidrug-resistant clinical isolate of Acinetobacter baumannii

<p>Abstract</p> <p>Background</p> <p><it>Acinetobacter baumannii </it>is emerging as an important nosocomial pathogen. Multidrug resistance, as well as ability to withstand environmental stresses, makes eradication of <it>A. baumannii </it>difficult, particularly from hospital settings.</p> <p>Results</p> <p>Over a six-year period, 73 isolates of <it>A. baumannii </it>were collected from infected patients in two hospitals in Italy. While 69 out of the 73 isolates displayed identical multidrug antibiotic resistance pattern, they were susceptible to carbapenems. Genetic profiles of these 69 isolates, determined by Pulsed Field Gel Electrophoresis (PFGE), indicated that they were genetically related and could be clustered in a specific clone, called SMAL. We tested the ability of the SMAL clone to form biofilm, an important determinant for bacterial colonization of the human host and for persistence in the hospital environment. Biofilm formation by <it>A. baumannii </it>SMAL, measured as surface adhesion to polystyrene, is strongly affected by growth conditions, being impaired in rich growth media such as LB, while being favoured in glucose-based medium. Surface adhesion in glucose-based media is inhibited by treatment with cellulase, suggesting that it depends on production of cellulose or of a chemically related extracellular polysaccharide. Exposure of <it>A. baumannii </it>SMAL to subinhibitory concentrations of imipenem resulted in biofilm stimulation and increased production of iron uptake proteins. Growth in iron-supplemented medium also stimulated surface adhesion, thus suggesting that increased intracellular iron concentrations might act as an environmental signal for biofilm formation in <it>A. baumannii </it>SMAL.</p> <p>Conclusions</p> <p>Our results indicate that exposure to subinhibitory concentrations of imipenem can stimulate biofilm formation and induce iron uptake in a pathogenic strain of <it>A. baumannii</it>, with potential implications on antibiotic susceptibility and ability to persist in the human host.</p

Dust properties inside molecular clouds from coreshine modeling and observations

Context. Using observations to deduce dust properties, grain size distribution, and physical conditions in molecular clouds is a highly degenerate problem. Aims. The coreshine phenomenon, a scattering process at 3.6 and 4.5 $\mu$m that dominates absorption, has revealed its ability to explore the densest parts of clouds. We want to use this effect to constrain the dust parameters. The goal is to investigate to what extent grain growth (at constant dust mass) inside molecular clouds is able to explain the coreshine observations. We aim to find dust models that can explain a sample of Spitzer coreshine data. We also look at the consistency with near-infrared data we obtained for a few clouds. Methods. We selected four regions with a very high occurrence of coreshine cases: Taurus-Perseus, Cepheus, Chameleon and L183/L134. We built a grid of dust models and investigated the key parameters to reproduce the general trend of surface bright- nesses and intensity ratios of both coreshine and near-infrared observations with the help of a 3D Monte-Carlo radiative transfer code. The grid parameters allow to investigate the effect of coagulation upon spherical grains up to 5 $\mu$m in size derived from the DustEm diffuse interstellar medium grains. Fluffiness (porosity or fractal degree), ices, and a handful of classical grain size distributions were also tested. We used the near- and mostly mid-infrared intensity ratios as strong discriminants between dust models. Results. The determination of the background field intensity at each wavelength is a key issue. In particular, an especially strong background field explains why we do not see coreshine in the Galactic plane at 3.6 and 4.5 $\mu$m. For starless cores, where detected, the observed 4.5 $\mu$m / 3.6 $\mu$m coreshine intensity ratio is always lower than $\sim$0.5 which is also what we find in the models for the Taurus-Perseus and L183 directions. Embedded sources can lead to higher fluxes (up to four times greater than the strongest starless core fluxes) and higher coreshine ratios (from 0.5 to 1.1 in our selected sample). Normal interstellar radiation field conditions are sufficient to find suitable grain models at all wavelengths for starless cores. The standard interstellar grains are not able to reproduce observations and, due to the multi-wavelength approach, only a few grain types meet the criteria set by the data. Porosity does not affect the flux ratios while the fractal dimension helps to explain coreshine ratios but does not seem able to reproduce near-infrared observations without a mix of other grain types. Conclusions. Combined near- and mid-infrared wavelengths confirm the potential to reveal the nature and size distribution of dust grains. Careful assessment of the environmental parameters (interstellar and background fields, embedded or nearby reddened sources) is required to validate this new diagnostic

An unusual case of venous thoracic outlet syndrome in relation to the anatomical position of the subclavian vein valves in a young athlete

Venous Thoracic Outlet Syndrome (vTOS) consists of upper extremities oedema, sometimes with varicose dilation of the superficial veins of the arm in consequence of compression and/or thrombosis of the subclavian vein. More specific factors, such as muscle hypertrophy, have additionally been registered in athletes. The case focuses on a 20-year-old male student in medicine, with an intense training activity in body building. The subject has presented symptoms of upper limbs oedema he has also reported heaviness and paresthesia in the left arm and hand. Varicose dilation of a superficial vein close to the axillary fossa was visible at naked eye. Both Doppler ultrasound evaluation and Angio TC were negative for venous thrombosis and/or complete obstruction from external compression. These reports depict an uncommon clinical scenario, which correlate an intense upper body training activity with the presence of a second valve distally of the first valve into the subclavian vein

Rapid and sensitive detection of bla KPC gene in clinical isolates of Klebsiella pneumoniae by a molecular real-time assay.

The aim of this study was the rapid identification of bla KPC gene in 38 Klebsiella pneumoniae clinical isolates with reduced susceptibility to carbapenems. The modified Hodge Test (MHT) was carried out to phenotypically determine whether resistance to carbapenems was mediated by a carbapenemase. The detection of the bla KPC gene was performed by real-time acid nucleic sequence-based amplification (NASBA™™), specifically designed for the detection of KPC RNA target.Thirty-two/38 isolates evaluated by MHT showed the production of carbapenemases, while all the strains exhibited the production of KPC by inhibition test with phenylboronic acid (the combined disk test with IPM/IPM plus phenylboronic acid). The detection of bla KPC gene by Nuclisens EasyQ KPC yielded positive results in 38/38 (100\%) strains. The presence of bla KPC gene was confirmed in all K. pneumoniae isolates when tested by the gold standard PCR assay.In consideration of the serious challenge represented by infections due to K. pneumoniae it appears necessary the rapid identification of carbapenemases in clinical settings as it is made possible by the use of NASBA™ assay

Evaluation of two commercially available methods used for the rapid detection of ESBL-producing strains

Detection of ESBL production by Enterobacteriaceae remains a challenge for microbiologists. Although recent changes in the breakpoints of third-generation cephalosporins decreased the likelihood of reporting ESBL producers as susceptible to these compounds, ESBL detection is of interest for prevention of dissemination of ESBL-producers by cross-transmission and for epidemiological purpose. The aim of this study was to evaluate the sensitivity and the specificity of two commercial methods suitable for rapid ESBL-detection in Gram negative bacilli: the ChromID ESBL medium (bioMérieux) and the Cica-ß-Test (Mast Group, Merseyde, UK). 121 Enterobacteriaceae collected between February 2008 and April 2009 at the Laboratory Analysis IRCCS Humanitas were tested for ESBL-production by PhoenixTM, E-test (ESBL reference test), ChromID ESBL medium and Cica-β-Test. ChromID showed 100% of sensitivity and specificity for the screening of ESBL in E. coli; lower values of specificity were found in the case of P. mirabilis (81%) and Klebsiella spp. (92%). The Cica-β-Test always showed high specificity levels, but the poor sensitivity found for both E. coli (90%), P. mirabilis (73%) and Klebsiella spp. (85%), discourages its use for screening of ESBL in Gram negative bacilli from blood-cultures. Rapid identification of ESBL producers is of interest to implement hygiene precautions. In that case, using a very sensitive primary test is of major interest

Multicenter prospective study on the prevalence of colistin resistance in escherichia coli: Relevance of mcr-1-positive clinical isolates in Lombardy, Northern Italy

Background: The emergence of the plasmid-mediated colistin resistance mechanism in Escherichia coli has raised concern among public health experts as colistin is a last-line antimicrobial resort. The primary aim of the study was to investigate the prevalence of this resistance trait in E. coli isolates circulating in the Lombardy region, Northern Italy. The presence of mcr-type genes and their genetic relationship were also studied. Materials and methods: A prospective study was performed during a 4-month period (May to August, 2016) in six acute care Hospitals. Consecutive nonduplicate clinical isolates of E. coli from any type of clinical specimen, with the exception of rectal swabs, were included in the study. Isolates that exhibited MIC values for colistin &gt;2 mg/L were further investigated. Bacterial identification was obtained by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Amplification of mcr-type genes (-1 to -5 variants) and microarray analysis were accomplished. Repetitive sequence-based PCR (Rep-PCR) and multilocus sequence typing (MLST) analysis were used for genotyping. Results: Overall, 3,902 consecutive E. coli isolates (2,342 from outpatients, 1,560 from inpatients) were evaluated during the study period. Of them, 18/3,902 (0.5%), collected from 4/6 centers, showed resistance to colistin. These isolates were mostly obtained from urine of both outpatients (n=12) and inpatients (n=6). Colistin MIC values ranged from 4 to 8 mg/L. The mcr-1 gene was detected in 10/18 isolates (7 from outpatients, 3 from inpatients). Rep-PCR and MLST analysis revealed the presence of nine different clusters. Further mcr-type genes were not detected. Conclusion: Resistance to colistin in E. coli clinical isolates appears low in our geographic area. With regard to mcr-1-positive isolates, they accounted for approximately 50% of colistin-resistant E. coli isolates, thus representing a relevant resistance mechanism in this context. Although overall limited, the presence of mcr-1 determinant in our region should not be ignored and great concern should be given to the continuous surveillance