Assessment of risk factors related to healthcare-associated methicillin-resistant Staphylococcus aureus infection at patient admission to an intensive care unit in Japan

<p>Abstract</p> <p>Background</p> <p>Healthcare-associated methicillin-resistant <it>Staphylococcus aureus </it>(HA-MRSA) infection in intensive care unit (ICU) patients prolongs ICU stay and causes high mortality. Predicting HA-MRSA infection on admission can strengthen precautions against MRSA transmission. This study aimed to clarify the risk factors for HA-MRSA infection in an ICU from data obtained within 24 hours of patient ICU admission.</p> <p>Methods</p> <p>We prospectively studied HA-MRSA infection in 474 consecutive patients admitted for more than 2 days to our medical, surgical, and trauma ICU in a tertiary referral hospital in Japan. Data obtained from patients within 24 hours of ICU admission on 11 prognostic variables possibly related to outcome were evaluated to predict infection risk in the early phase of ICU stay. Stepwise multivariate logistic regression analysis was used to identify independent risk factors for HA-MRSA infection.</p> <p>Results</p> <p>Thirty patients (6.3%) had MRSA infection, and 444 patients (93.7%) were infection-free. Intubation, existence of open wound, treatment with antibiotics, and steroid administration, all occurring within 24 hours of ICU admission, were detected as independent prognostic indicators. Patients with intubation or open wound comprised 96.7% of MRSA-infected patients but only 57.4% of all patients admitted.</p> <p>Conclusions</p> <p>Four prognostic variables were found to be risk factors for HA-MRSA infection in ICU: intubation, open wound, treatment with antibiotics, and steroid administration, all occurring within 24 hours of ICU admission. Preemptive infection control in patients with these risk factors might effectively decrease HA-MRSA infection.</p

Transmission of highly virulent community-associated MRSA ST93 and livestock-associated MRSA ST398 between humans and pigs in Australia

Pigs have been recognised as a reservoir of livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in Europe, Asia and North America. However, little is known about the presence and distribution of MRSA in the Australian pig population and pig industry. This study describes the presence, distribution and molecular characteristics of the human adapted Australian CA-MRSA ST93 isolated from pigs, people, and the environment within a piggery. Isolates were subjected to antibiotic susceptibility testing, DNA microarray, whole genome sequencing, multi locus sequence typing, virulence and resistance gene characterization and phylogenetic analysis. MRSA were isolated from 60% (n = 52) of farm workers where 84% of isolates returned ST93 and the rest ST398. Of the thirty-one pig isolates tested further, an equal number of ST398 and ST93 (15 each) and one as ST30-V were identified. Four of six environmental isolates were identified as ST93 and two as ST398. This study has identified for the first time in Australia the occurrence of CA-MRSA ST93 and LA-MRSA ST398 amongst farm workers, pigs, and the farm environment. Comparative genome analysis indicates that ST398 is likely to have been introduced into Australia from Europe or North America. This study also reports the first linezolid resistant MRSA isolated in Australia

Mechanistic insights into the catalytic methanol steam reforming performance of Cu/ZrO2 catalysts by in situ and operando studies

We assessed the catalytic properties of the Cu/ZrO2 interface in methanol and formaldehyde steam reforming (MSR and FSR) on powder catalysts by using a comparative approach with respect to the influence of the ZrO2 polymorph support structure (monoclinic (m-)ZrO2 vs. tetragonal (t-)ZrO2), its synthesis routine and the choice of the precursor material on the CO2 selectivity. Our studies reveal that ZrO2 exhibits a pronounced versatility as a support material and its catalytic properties depend most strongly on its surface properties governed by its synthesis, especially by the choice of the Zr precursor. The way of combining the support with copper introduces an additional layer of complexity, but its influence on the MSR performance is limited to a modification of the conditions provided by the ZrO2 support. Exploiting the comparative approach regarding the Cu-ZrO2 catalysts in FSR and MSR – including the pure support materials – in combination with in situ Fourier transform infrared (FT-IR) spectroscopy shows that the CO observed in MSR on Cu/m-ZrO2 can be attributed to a spillover of formaldehyde to the support. Side reactions of m-ZrO2 are suppressed at lower temperatures due to its lack of highly reactive sites, resulting in a CO2-selective MSR performance. In Cu/t-ZrO2, however, the amount of CO is higher and a combination of a formaldehyde spillover to the support and a Cu-ZrO2 phase boundary yielding CO leads to the lower CO2 selectivity of these samples. An elevated number of defects and reactive Lewis acidic and Brønsted basic centers of t-ZrO2 explains this increased activity towards side reactions in contrast to Cu/m-ZrO2 catalysts

Prevalence of colonization by methicillin-resistant Staphylococcus aureus ST398 in pigs and pig farm workers in an area of Catalonia, Spain

Background: A livestock-associated clonal lineage (ST398) of methicillin-resistant Staphylococcus aureus (MRSA) has been identified causing colonization or infection in farm workers. The aim of the study was to analyze the prevalence of MRSA-ST398 colonization in pigs and in pig farmers in an area with a high pig population (Osona, Barcelona province, Catalonia, Spain). Methods: We performed a cross-sectional prevalence study in Osona (Catalonia, Spain), from June 2014 to June 2015. All pig farm workers from 83 farms were studied. Twenty of these farms were randomly selected for the study of both pigs and farmers: 9 fattening and 11 farrow-to-finish farms. All workers over the age of 18 who agreed to participate were included. Samples were analyzed to identify MRSA-ST398 and their spa type. Results: Eighty-one of the 140 pig farm workers analyzed (57.9% (95% IC: 50.0-66.4%)) were MRSA-positive, all of them ST398. The mean number of years worked on farms was 17.5 ± 12.6 (range:1-50), without significant differences between positive and negative MRSA results (p = 0.763). Over 75% of MRSA-ST398 carriers worked on farms with more than 1250 pigs (p < 0.001). At least one worker tested positive for MRSA-ST398 on all 20 selected pig farms. Ninety-two (46.0% (95% IC: 39.0-53.0%)) of the nasal swabs from 200 pigs from these 20 farms were MRSA-positive, with 50.5% of sows and 41.4% of fattening pigs (p = 0.198) giving MRSA-positive results. All the isolates were tetracycline-resistant, and were identified as MRSA-ST398. The spa type identified most frequently was t011 (62%). Similar spa types and phenotypes of antibiotic resistance were identified in pigs and farmers of 19/20 tested farms. Conclusions: The prevalence of MRSA-ST398 among pig farm workers and pigs on farms in the studied region is very high, and the size of the farm seems to correlate with the frequency of colonization of farmers. The similar spa-types and phenotypes of resistance detected in pigs and workers in most of the farms studied suggest animal-to-human transmission. © 2016 The Author(s)