Impact of colonization pressure on acquisition of extended-spectrum ß-lactamase-producing Enterobacterales and meticillin-resistant Staphylococcus aureus in two intensive care units: a 19-year retrospective surveillance.

BACKGROUND: Colonization pressure is a risk factor for intensive care unit (ICU)-acquired multi-drug-resistant organisms (MDROs). AIM: To measure the long-term respective impact of colonization pressure on ICU-acquired extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-PE) and meticillin-resistant Staphylococcus aureus (MRSA). METHODS: All patients admitted to two ICUs (medical and surgical) between January 1997 and December 2015 were included in this retrospective observational study. Rectal and nasal surveillance cultures were obtained at admission and weekly thereafter. Contact precautions were applied for colonized or infected patients. Colonization pressure was defined as the ratio of the number of MDRO-positive patient-days (PDs) of each MDRO to the total number of PDs. Single-level negative binomial regression models were used to evaluate the incidence of weekly MDRO acquisition. FINDINGS: Among the 23,423 patients included, 2327 (10.0%) and 1422 (6.1%) were colonized with ESBL-PE and MRSA, respectively, including 660 (2.8%) and 351 (1.5%) acquisitions. ESBL-PE acquisition increased from 0.51/1000 patient-exposed days (PEDs) in 1997 to 6.06/1000 PEDs in 2015 (P<0.001). In contrast, MRSA acquisition decreased steadily from 3.75 to 0.08/1000 PEDs (P<0.001). Controlling for period-level covariates, colonization pressure in the previous week was associated with MDRO acquisition for ESBL-PE (P<0.001 and P=0.04 for medical and surgical ICU, respectively), but not for MRSA (P=0.34 and P=0.37 for medical and surgical ICU, respectively). The increase in colonization pressure was significant above 100/1000 PDs for ESBL-PE. CONCLUSION: Colonization pressure contributed to the increasing incidence of ESBL-PE but not MRSA. This study suggests that preventive control measures should be customized to MDROs.

Prevalence of carriage of extended-spectrum ß-lactamase-producing enterobacteria and associated factors in a French hospital.

OBJECTIVES: Our aim was to evaluate the prevalence and associated factors for carriage of extended-spectrum ß-lactamase-producing enterobacteria (ESBL-PE) in a healthcare facility. METHODS: In 2016 a serial cross-sectional survey of ESBL-PE carriage in a French university hospital was conducted. All patients present on the day of the survey were screened for ESBL-PE carriage. Demographic characteristics and risk factors for ESBL-PE carriage were collected. RESULTS: In all, 146/844 patients (17%) were digestive carriers of ESBL-PE; of these, 96 (66%) had not previously been identified. Among patients carrying ESBL-PE, Escherichia coli (62%) and CTX-M type (94%) predominated. Greater age, recent travel abroad, receipt of antibiotic, and prolonged hospitalization were associated with ESBL-PE carriage. CONCLUSION: Given the high prevalence of ESBL-PE and the high proportion of unknown carriers, our results strongly suggest reinforcing standard precautions rather than contact precautions for controlling the spread of ESBL-PE.

Surgical site infection with extended-spectrum ß-lactamase-producing Enterobacteriaceae after cardiac surgery: incidence and risk factors.

OBJECTIVE: To determine the incidence, microbiology and risk factors for sternal wound infection (SWI) with extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-PE) following cardiac surgery. METHODS: We performed a retrospective analysis between January 2006 and December 2015 of prospective surveillance of a cohort of patients with cardiac surgery at a single centre (Paris, France). SWI was defined as the need for reoperation due to sternal infection. All patients with an initial surgery under extracorporeal circulation and diagnosed with an SWI caused by Enterobacteriaceae isolates were included. We compared patients infected with at least one ESBL-PE with those with SWI due to other Enterobacteriaceae by logistic regression analysis. RESULTS: Of the 11 167 patients who underwent cardiac surgery, 412 (3.7%) developed SWI, among which Enterobacteriaceae were isolated in 150 patients (36.5%), including 29 ESBL-PE. The main Enterobacteriaceae (n = 171) were Escherichia coli in 49 patients (29%) and Enterobacter cloacae in 26 (15%). Risk factors for SWI with ESBL-PE in the multivariate logistic regression were previous intensive care unit admission during the preceding 6 months (adjusted odds ratio (aOR) 12.2; 95% CI 3.3-44.8), postoperative intensive care unit stay before surgery for SWI longer than 5 days (aOR 4.6; 95% CI 1.7-11.9) and being born outside France (aOR 3.2; 95% CI 1.2-8.3). CONCLUSIONS: Our results suggest that SWI due to ESBL-PE was associated with preoperative and postoperative unstable state, requiring an intensive care unit stay longer than the usual 24 or 48 postoperative hours, whereas being born outside France may indicate ESBL-PE carriage before hospital admission.

[French recommendations on control measures to reduce the infectious risk in immunocompromised patients]. / Quelles mesures pour maîtriser le risque infectieux chez les patients immunodéprimés ? Recommandations formalisées d'experts.

The increase use of immunosuppressive treatments in patients with solid cancer and/or inflammatory diseases requires revisiting our practices for the prevention of infectious risk in the care setting. A review of the literature by a multidisciplinary working group at the beginning of 2014 wished to answer the following 4 questions to improve healthcare immunocompromised patients: (I) How can we define immunocompromised patients with high, intermediate and low infectious risk, (II) which air treatment should be recommended for this specific population? (III) What additional precautions should be recommended for immunocompromised patients at risk for infection? (IV) Which global environmental control should be recommended? Based on data from the literature and using the GRADE method, we propose 15 recommendations that could help to reduce the risk of infection in these exposed populations.

Healthcare workers' knowledge and perceptions of the risks associated with emerging extensively drug-resistant bacteria.

OBJECTIVE: Guidelines have been issued in 2010 to prevent the spread of emerging extensively resistant bacteria (eXDR), but their implementation is difficult. We aimed to evaluate healthcare workers' (HCW) knowledge and their risk perception to identify barriers to the implementation of guidelines. METHODS: Semi-structured interviews were conducted at a University Hospital, where case patients are regularly admitted. The interviews focused on HCW's knowledge, risk perception, and challenges met. The evaluation of HCW's knowledge and contagiousness and perception of severity of eXDR carriage were analyzed statistically. Risk perception and opinion about guidelines were analyzed by qualitative description. RESULTS: One hundred and twenty-one HCWs were interviewed. The category of HCW, having searched for information on resistant bacteria, and having taken care of case patients were associated with better knowledge. The HCW category, age, type of unit, seniority, and having taken care of case patients were associated with risk perceptions. Qualitative analysis identified 61 themes. HCWs were extremely concerned by the spread of bacteria within the hospital. The main challenges identified were organizational and communication issues. CONCLUSION: HCWs reported a lack of knowledge and a lack of resources to implement guidelines. Strategies to improve guidelines implementation must be based on a better availability of resources, better communication, and new educational methods.

First nosocomial outbreak of vanA-type vancomycin-resistant Enterococcus raffinosus in France.

BACKGROUND: Vancomycin-resistant Enterococcus raffinosus has rarely been associated with nosocomial infection and outbreaks. AIM: To report the successful control of a nosocomial outbreak of vanA-type vancomycin-resistant E. raffinosus in a surgical intensive care unit. METHODS: The investigation of the outbreak is reported with control measures taken. Molecular typing of vancomycin-resistant E. raffinosus isolates was performed by repetitive sequence-based polymerase chain reaction (PCR). FINDINGS: Between September and October 2014, vancomycin-resistant E. raffinosus isolates were isolated from four patients. The index patient had been hospitalized previously in Portugal, and was not found to be colonized by vancomycin-resistant enterococci on screening cultures obtained at admission. However, vancomycin-resistant E. raffinosus was isolated from a bile sample 19 days after hospital admission. All four isolates were resistant to both vancomycin and teicoplanin due to the presence of the vanA gene, while remaining susceptible to daptomycin and linezolid. Repetitive sequence-based PCR confirmed the spread of a single vanA-positive E. raffinosus clone. Infection control measures including direct PCR screening on rectal specimens, contact precautions, and cohorting of patients and personnel led to successful control of the outbreak. CONCLUSION: This is the first reported outbreak of vanA-type vancomycin-resistant E. raffinosus in France in both clinical and screening specimens among hospitalized patients. The inability of routine selective screening media to detect the vancomycin-resistant E. raffinosus in the index case likely contributed to the outbreak.

Evaluation of inter-observer agreement when using a clinical respiratory scoring system in pre-weaned dairy calves.

AIM: To determine inter-observer agreement for a clinical scoring system for the detection of bovine respiratory disease complex in calves, and the impact of classification of calves as sick or healthy based on different cut-off values. METHODS: Two third-year veterinary students (Observer 1 and 2) and one post-graduate student (Observer 3) received 4 hours of training on scoring dairy calves for signs of respiratory disease, including rectal temperature, cough, eye and nasal discharge, and ear position. Observers 1 and 2 scored 40 pre-weaning dairy calves 24 hours apart (80 observations) over three visits to a calf-rearing facility, and Observers 1, 2 and 3 scored 20 calves on one visit. Inter-observer agreement was assessed using percentage of agreement (PA) and Kappa statistics for individual clinical signs, comparing Observers 1 and 2. Agreement between the three observers for total clinical score was assessed using cut-off values of ≥4, ≥5 and ≥6 to indicate unhealthy calves. RESULTS: Inter-observer PA for rectal temperature was 0.68, for cough 0.78, for nasal discharge 0.62, for eye discharge 0.63, and for ear position 0.85. Kappa values for all clinical signs indicated slight to fair agreement (<0.4), except temperature that had moderate agreement (0.6). The Fleiss' Kappa for total score, using cut-offs of ≥4, ≥5 and ≥6 to indicate unhealthy calves, was 0.35, 0.06 and 0.13, respectively, indicating slight to fair agreement. CONCLUSIONS AND CLINICAL RELEVANCE: There was important inter-observer discrepancies in scoring clinical signs of respiratory disease, using relatively inexperienced observers. These disagreements may ultimately mean increased false negative or false positive diagnoses and incorrect treatment of cases. Visual assessment of clinical signs associated with bovine respiratory disease needs to be thoroughly validated when disease monitoring is based on the use of a clinical scoring system.

The maternal chromosome set is the target of the T-DNA in the in planta transformation of Arabidopsis thaliana.

In planta transformation methods are now commonly used to transform Arabidopsis thaliana by Agrobacterium tumefaciens. The origin of transformants obtained by these methods has been studied by inoculating different floral stages and examining gametophytic expression of an introduced beta-glucuronidase marker gene encoding GUS. We observed that transformation can still occur after treating flowers where embryo sacs have reached the stage of the third division. No GUS expression was observed in embryo sacs or pollen of plants infiltrated with an Agrobacterium strain bearing a GUS gene under the control of a gametophyte-specific promoter. To identify the genetic target we used an insertion mutant in which a gene essential for male gametophytic development has been disrupted by a T-DNA bearing a Basta resistance gene (B(R)). In this mutant the B(R) marker is transferred to the progeny only by the female gametes. This mutant was retransformed with a hygromycin resistance marker and doubly resistant plants were selected. The study of 193 progeny of these transformants revealed 25 plants in which the two resistance markers were linked in coupling and only one plant where they were linked in repulsion. These results point to the chromosome set of the female gametophyte as the main target for the T-DNA.

Kinetic study of the oxidation of gamma-L-glutaminyl-4-hydroxybenzene catalyzed by mushroom (Agaricus bisporus) tyrosinase.

Despite the importance of the substrate gamma-L-glutaminyl-4-hydroxybenzene (GHB) in the melanin biosynthesis pathway in mushrooms Agaricus bisporus, the kinetics of its oxidation catalyzed by tyrosinase has never been properly characterized. For this purpose GHB and its corresponding o-diphenol (GDHB) were isolated and purified from A. bisporus mushrooms. The kinetic constants that characterize the action of tyrosinase on GHB and GDHB are = 2.10 +/- 0.10 microM/min, = 0.30 +/- 0.03 mM, = 210.0 +/- 7.3 microM/min, and = 7.80 +/- 0.41 mM. The oxygen kinetic constants for tyrosinase in the presence of these compounds are = 3. 20 +/- 0.21 microM/min, = 1.50 +/- 0.12 microM, = 200.2 +/- 8.1 microM/min, and = 100.2 +/- 8.2 microM. These values were compared to those obtained for the pair L-tyrosine/L-DOPA. The kinetic and structural reaction mechanisms of tyrosinase were corroborated for these physiological phenolic compounds.

Biochemical and physiological aspects of brown blotch disease of Agaricus bisporus.

Pseudomonas tolaasii is a bacterium endemic to the compost beds where common mushroom (Agaricus bisporus) is cultivated. Under some environmental conditions still not well-determined, but influenced by temperature and relative humidity, the bacterium can become pathogenic and provoke the brown blotch disease. This review describes the interaction between P. tolaasii and A. bisporus that results in the appearance of brown spots on the mushroom caps, typical symptoms of the disease. Firstly, P. tolaasii is studied, the changes in pathogenicity are explained, the compounds that provoke the damage are enumerated as well as various experimental methods to identify the pathogenic form of the bacteria. Secondly, mechanisms involved in the formation of the brown colour on the A. bisporus caps upon infection are briefly mentioned, taking into account the enzymes that catalyse the reaction, their mechanism, substrates and reaction products. Afterwards, a detailed description of the infection process is presented step by step, starting by the chemotactical attraction, fixation, secretion of the toxins, membrane breakdown, effect of the toxin on mushroom polyphenol oxidases and on the discolouration reaction. A possible mechanism of infection is hypothesised at the molecular level. Finally, the strategies tested until now to control the disease are discussed.