Assessment of a rapid diagnostic test to exclude bacteraemia and effect on clinical decision-making for antimicrobial therapy.

Unnecessary antimicrobial treatment promotes the emergence of resistance. Early confirmation that a blood culture is negative could shorten antibiotic courses. The Cognitor Minus test, performed on blood culture samples after 12 hours incubation has a negative predictive value (NPV) of 99.5%. The aim of this study was to determine if earlier confirmation of negative blood culture result would shorten antibiotic treatment. Paired blood cultures were taken in the Critical Care Unit at a teaching hospital. The Cognitor Minus test was performed on one set >12 hours incubation but results kept blind. Clinicians were asked after 24 and 48 hours whether a result excluding bacteraemia or fungaemia would affect decisions to continue or stop antimicrobial treatment. Over 6 months, 125 patients were enrolled. The median time from start of incubation to Cognitor Minus test was 27.1 hours. When compared to 5 day blood culture results from both the control and test samples, Cognitor Minus gave NPVs of 99% and 100% respectively. Test results would have reduced antibiotic treatment in 14% (17/119) of patients at 24 and 48 hours (24% at either time) compared with routine blood culture. The availability of rapid tests to exclude bacteraemia may be of benefit in antimicrobial stewardship.

Identification of Clostridium difficile Reservoirs in The Patient Environment and Efficacy of Aerial Hydrogen Peroxide Decontamination.

OBJECTIVE To identify, using a novel enhanced method of recovery, environmental sites where spores of Clostridium difficile persist despite cleaning and hydrogen peroxide aerial decontamination. DESIGN Cohort study. SETTING Tertiary referral center teaching hospital. METHODS In total, 16 sites representing high-frequency contact or difficult-to-clean surfaces in a single-isolation room or bed area in patient bed bays were sampled before and after terminal or hydrogen peroxide disinfection using a sponge swab. In some rooms, individual sites were not present (eg, there were no en-suite rooms in the ICU). Swab contents were homogenized, concentrated by membrane-filtration, and plated onto selective media. Results of C. difficile sampling were used to focus cleaning. RESULTS Over 1 year, 2,529 sites from 146 rooms and 44 bays were sampled. Clostridium difficile was found on 131 of 572 surfaces (22.9%) before terminal cleaning, on 105 of 959 surfaces (10.6%) after terminal cleaning, and on 43 of 967 surfaces (4.4%) after hydrogen peroxide disinfection. Clostridium difficile persisted most frequently on floor corners (97 of 334; 29.0%) after disinfection. Between the first and third quarters, we observed a significant decrease in the number of positive sites (25 of 390 vs 6 of 256). However, no similar change in the number of isolates before terminal cleaning was observed. CONCLUSION Persistence of C. difficile in the clinical environment was widespread. Although feedback of results did not improve the efficacy of manual disinfection, numbers of C. difficile following hydrogen peroxide gradually declined. Infect Control Hosp Epidemiol 2017;38:1487-1492.

A Novel Quantitative Sampling Technique for Detection and Monitoring of Clostridium difficile Contamination in the Clinical Environment.

The horizontal transmission of Clostridium difficile in the hospital environment is difficult to establish. Current methods to detect C. difficile spores on surfaces are not quantitative, lack sensitivity, and are protracted. We propose a novel rapid method to detect and quantify C. difficile contamination on surfaces. Sponge swabbing was compared to contact plate sampling to assess the in vitro recovery of C. difficile ribotype 027 contamination (∼10(0), 10(1), or 10(2) CFU of spores) from test surfaces (a bed rail, a stainless steel sheet, or a polypropylene work surface). Sponge swab contents were concentrated by vacuum filtration, and the filter membrane was plated onto selective agar. The efficacy of each technique for the recovery of C. difficile from sites in the clinical environment that are touched at a high frequency was evaluated. Contact plates recovered 19 to 32% of the total contamination on test surfaces, whereas sponge swabs recovered 76 to 94% of the total contamination, and contact plates failed to detect C. difficile contamination below a detection limit of 10 CFU/25 cm(2) (0.4 CFU/cm(2)). In use, contact plates failed to detect C. difficile contamination (0/96 contact plates; 4 case wards), while sponge swabs recovered C. difficile from 29% (87/301) of the surfaces tested in the clinical environment. Approximately 74% (36/49) of the area in the vicinity of the patient was contaminated (∼1.34 ± 6.88 CFU/cm(2) C. difficile spores). Reservoirs of C. difficile extended to beyond the areas near the patient: a dirty utility room sink (2.26 ± 5.90 CFU/cm(2)), toilet floor (1.87 ± 2.40 CFU/cm(2)), and chair arm (1.33 ± 4.69 CFU/cm(2)). C. difficile was present on floors in ∼90% of case wards. This study highlights that sampling with a contact plate may fail to detect C. difficile contamination and result in false-negative reporting. Our sponge sampling technique permitted the rapid and quantitative measurement of C. difficile contamination on surfaces with a sensitivity (limit, 0 CFU) greater than that which is otherwise possible. This technique could be implemented for routine surface hygiene monitoring for targeted cleaning interventions and as a tool to investigate routes of patient-patient transmission in the clinical environment.

The type, level, and distribution of microorganisms within the ward environment: a zonal analysis of an intensive care unit and a gastrointestinal surgical ward.

OBJECTIVE. To investigate the distribution of hospital pathogens within general and critical care ward environments and to determine the most significant bacterial reservoirs within each ward type. DESIGN. Prospective 4-month microbiological survey. SETTING. The intensive care unit (ICU) and gastrointestinal (GI) surgical ward of a London teaching hospital. PATIENTS. Sampling was conducted in and around the bed space of 166 different patients (99 in the ICU and 67 in the GI ward). METHODS. Conventional agar contact methodology was used to sample 123 predetermined sites twice a week for 17 weeks. Sixty-one surfaces were located within the ICU, and 62 were located within the GI ward. Each surface was located within a theoretical zone of increasing distance from the patient. Aerobic colony counts were determined, and confirmatory testing was conducted on all presumptive pathogens. RESULTS. Regardless of ward type, surfaces located closest to the patient, specifically those associated with the bed (side rails, bed control, and call button), were the most heavily contaminated. Elsewhere, the type of surfaces contaminated differed with ward type. In the ICU, bacteria were most likely to be on surfaces that were regularly touched by healthcare workers (e.g., telephones and computer keyboards). In the GI ward, where the patients were mobile, the highest numbers of bacteria (including potential nosocomial pathogens) were on surfaces that were mainly touched by patients, particularly their toilet and shower facilities. CONCLUSIONS. In terms of cleaning, a hospital should not be considered a single entity. Different ward types should be treated as separate environments, and cleaning protocols should be adjusted accordingly.

Dissemination of antibiotic-resistant enterococci within the ward environment: the role of airborne bacteria and the risk posed by unrecognized carriers.

BACKGROUND: Colonized or infected patients pose a significant risk to noncolonized patients occupying the same room. The aim of this study was to investigate how far Enterococcus spp can spread from isolated and nonisolated patients. METHODS: Conventional microbiological methods were used to recover enterococci from the air and from 62 high-contact sites located within the near-patient and wider ward environment. Samples were collected twice weekly for 17 weeks. The similarity between isolates was determined via pulsed-field gel electrophoresis. RESULTS: Vancomycin-susceptible enterococci (VSE) were recovered from 352 of 2,046 environmental surfaces (17.2%) and from 27 of 66 air samples (40.9%). During study week 14, VSE was recovered from 75 of the 124 surfaces sampled, representing 21.3% of all VSE-positive sites. A gentamicin-resistant VS Enterococcus faecium clone was recovered in high numbers from the air (>100 cfu/m(3)) and from surfaces throughout a 4-bed bay. The same clone was recovered from an adjacent isolation room as well. A total of 55 surfaces were contaminated with vancomycin-resistant enterococci (VRE). The environment of 2 isolated patients accounted for 85% of contaminated sites. Neither patient was known to be VRE-positive. CONCLUSIONS: Unrecognized colonization and/or the aerosolization of enterococci together with inadequate cleaning can lead to heavy, widespread, and persistent environmental contamination. All pose a significant risk for acquisition of antibiotic-resistant enterococci.

Molecular characterization of vancomycin-resistant Enterococcus spp. clinical isolates from Hungary and Serbia.

The objectives of this work were to collect and characterize vancomycin-resistant Enterococcus faecium (VREF) clinical isolates from Hungary and Serbia and to analyse their genetic relatedness. VREF isolates were initially typed by PFGE. A selection of VREF isolates representing all participating hospitals was further examined by multiple-locus variable-number tandem repeat analysis (MLVA) and multilocus sequence typing (MLST). VanB VREF isolates (n=18) recovered from blood, urine and faecal cultures at a Budapest hospital between August 2003 and December 2004 were molecularly characterized. Macrorestriction analysis of the isolates revealed their monoclonal relatedness. A cluster of infections caused by 2 distinct VanA VREF clones recovered from 6 departments was identified in a Belgrade hospital in Serbia. The vanA resistance determinant was transferable by in vitro conjugation experiments. We also identified 2 vanA-positive E. gallinarum blood culture isolates in this Belgrade hospital. Molecular typing of representative VREF isolates from Hungary and Serbia by MLVA and MLST revealed that all tested isolates belonged to MLST complex CC17 and the corresponding MLVA cluster 1. Our results extend the documented occurrence of CC17 to a new region in Europe.

Molecular typing indicates an important role for two international clonal complexes in dissemination of VIM-producing Pseudomonas aeruginosa clinical isolates in Hungary.

VIM metallo-beta-lactamase-producing serotype O11 or O12 Pseudomonas aeruginosa isolates infecting or colonising 19 patients from seven hospitals were reported in Hungary between 2003 and 2005. In this study we characterised VIM-producing Pseudomonas spp. clinical isolates from two novel locations in Hungary; we identified three new bla(VIM) carrying integron types and the presence of the bla(VIM-2) allele in Hungary. By applying various typing techniques, including multilocus sequence typing, we revealed an important role of two international clonal complexes, CC4 and CC11, in the dissemination of bla(VIM)-positive P. aeruginosa in hospitals in Hungary. Isolate P12-Q, a representative strain from France of the major European multiresistant P12 clone, displayed ST111 which, according to eBURST analysis, is the presently calculated founder sequence type of CC4. This is in accordance with the wide geographic distribution of the P12 clone. Our data indicate that, although the CC4 clonal complex includes serotype O1 and O6 isolates as well, it also contains the P12 clone. We characterised a P. aeruginosa nosocomial clone with a singleton sequence type (ST313), that may have acquired bla(VIM-2) and bla(VIM-4) gene cassettes from a yet unidentified local gene pool in Hungary.

Molecular epidemiology of VIM-4 metallo-beta-lactamase-producing Pseudomonas sp. isolates in Hungary.

VIM metallo-beta-lactamase-producing serotype O11 or O12 Pseudomonas aeruginosa isolates infecting or colonizing 19 patients from seven hospitals in Hungary were characterized between October 2003 and November 2005. Macrorestriction analysis revealed the involvement of hospitals from three different towns in northwest Hungary in an outbreak caused by VIM-4-producing P. aeruginosa.

Isolation of an integron-borne blaVIM-4 type metallo-beta-lactamase gene from a carbapenem-resistant Pseudomonas aeruginosa clinical isolate in Hungary.

The first integron-borne metallo-beta-lactamase gene was isolated in Hungary. The bla(VIM-4) gene is located on a class 1 integron that also carries a novel bla(OXA)-like gene. The integron is harbored by a serotype O12 Pseudomonas aeruginosa strain and shows high structural similarity to integrons isolated in Greece and Poland.