Elaine Cloutman-Green

Chlorhexidine antisepsis significantly reduces the incidence of sepsis and septicemia during parenteral nutrition in surgical infants.

BACKGROUND/PURPOSE After a change in national policy, central venous catheter (CVC) antisepsis with chlorhexidine was introduced in our hospital. Our aim was to evaluate whether this change reduced the rate of infection seen during parenteral nutrition (PN) in infants requiring gastrointestinal surgery. METHODS Two groups of consecutive infants were compared: control, 98 infants who had CVC antisepsis with 70% isopropanol alone, and chlorhexidine, 112 infants who had CVC antisepsis with 2% chlorhexidine in 70% isopropanol. Incidence rates of sepsis (blood cultures taken) and septicemia (blood cultures positive) were compared by Poisson regression. RESULTS Seventy-one percent of infants experienced clinically suspected sepsis. The incidence of septicemia was 32%. The incidence rate ratio for sepsis was 0.72 (95% confidence interval, 0.61-0.84) for the chlorhexidine group vs control (P < .0005). The incidence rate ratio for septicemia was 0.49 (95% confidence interval, 0.36-0.67; P < .0005); that is, over a given period of PN, patients had half the rate of positive blood cultures after the introduction of chlorhexidine antisepsis compared with before. CONCLUSION (1) The incidence of sepsis and septicemia among surgical infants on PN for gastrointestinal anomalies is high. (2) Chlorhexidine CVC antisepsis has significantly reduced this incidence, and we advocate its use in this group of patients.

Gyrospun antimicrobial nanoparticle loaded fibrous polymeric filters

A one step approach to prepare hybrid nanoparticle embedded polymer fibres using pressurised gyration is presented. Two types of novel antimicrobial nanoparticles and poly(methylmethacrylate) polymer were used in this work. X-ray diffraction analysis of the nanoparticles revealed Ag, Cu and W are the main elements present in them. The concentration of the polymer solution and the nanoparticle concentration had a significant influence on the fibre diameter, pore size and morphology. Fibres with a diameter in the range of 6-20μm were spun using 20wt% polymer solutions containing 0.1, 0.25 and 0.5 wt% nanoparticles under 0.3MPa working pressure and a rotational speed of 36,000rpm. Continuous, bead-free fibre morphologies were obtained for each case. The pore size in the fibres varied between 36 and 300nm. Successful incorporation of the nanoparticles in polymer fibres was confirmed by energy dispersive x-ray analysis. The fibres were also gyrospun on to metallic discs to prepare filters which were tested for their antibacterial activity on a suspension of Pseudomonas aeruginosa. Nanoparticle loaded fibres showed higher antibacterial efficacy than pure poly(methylmethacrylate) fibres.

Hospital Door Handle Design and Their Contamination with Bacteria: A Real Life Observational Study. Are We Pulling against Closed Doors?

Objective To determine whether microbial contamination of door handles in two busy intensive care units and one high dependency unit was related to their design, location, and usage. Design Observational study of the number of viable bacteria on existing door handles of different design at defined entry/exit points with simultaneous data collection of who used these doors and how often. Setting Two busy specialised intensive care units and one high dependency unit in a tertiary referral NHS neurological hospital. Main outcome measures Surface bacterial density on door handles with reference to design, location, and intensity of use. Results We found a significant correlation between the frequency of movements through a door and the degree to which it was contaminated (p = <0.01). We further found that the doors location, design and mode of use all influenced contamination. When compared to push plate designs, pull handles revealed on average a five fold higher level of contamination; lever handles, however, displayed the highest levels of bacterial contamination when adjusted for frequency of use. We also observed differences in contamination levels at doors between clinical areas, particularly between the operating theatres and one of the ICUs. Conclusions Door handles in busy, “real life” high acuity clinical environments were variably contaminated with bacteria, and the number of bacteria found related to design, location, mode and frequency of operation. Largely ignored issues of handle and environmental design can support or undermine strategies designed to limit avoidable pathogen transmission, especially in locations designed to define “thresholds” and impose physical barriers to pathogen transmission between clinical areas. Developing a multidisciplinary approach beyond traditional boundaries for purposes of infection control may release hitherto unappreciated options and beneficial outcomes for the control of at least some hospital acquired infections.

International Multicenter Evaluation of the DiversiLab Bacterial Typing System for Escherichia coli and Klebsiella spp.

ABSTRACT Successful multidrug-resistant clones are increasing in prevalence globally, which makes the ability to identify these clones urgent. However, adequate, easy-to-perform, and reproducible typing methods are lacking. We investigated whether DiversiLab (DL), an automated repetitive-sequence-based PCR bacterial typing system (bioMérieux), is suitable for comparing isolates analyzed at different geographic centers. A total of 39 Escherichia coli and 39 Klebsiella species isolates previously typed by the coordinating center were analyzed. Pulsed-field gel electrophoresis (PFGE) confirmed the presence of one cluster of 6 isolates, three clusters of 3 isolates, and three clusters of 2 isolates for each set of isolates. DL analysis was performed in 11 centers in six different countries using the same protocol. The DL profiles of 425 E. coli and 422 Klebsiella spp. were obtained. The DL system showed a lower discriminatory power for E. coli than did PFGE. The local DL data showed a low concordance, as indicated by the adjusted Rand and Wallace coefficients (0.132 to 0.740 and 0.070 to 1.0 [E. coli] and 0.091 to 0.864 and 0.056 to 1.0 [Klebsiella spp.], respectively). The central analysis showed a significantly improved concordance (0.473 to 1.0 and 0.290 to 1.0 [E. coli] and 0.513 to 0.965 and 0.425 to 1.0 [Klebsiella spp.], respectively). The misclassifications of profiles for individual isolates were mainly due to inconsistent amplification, which was most likely due to variations in the quality and amounts of the isolated DNA used for amplification. Despite local variations, the DL system has the potential to indicate the occurrence of clonal outbreaks in an international setting, provided there is strict adherence to standardized, reproducible DNA isolation methods and analysis protocols, all supported by a central database for profile comparisons.

Use of UV-C radiation to disinfect non-critical patient care items: a laboratory assessment of the Nanoclave Cabinet

BackgroundThe near-patient environment is often heavily contaminated, yet the decontamination of near-patient surfaces and equipment is often poor. The Nanoclave Cabinet produces large amounts of ultraviolet-C (UV-C) radiation (53 W/m2) and is designed to rapidly disinfect individual items of clinical equipment. Controlled laboratory studies were conducted to assess its ability to eradicate a range of potential pathogens including Clostridium difficile spores and Adenovirus from different types of surface.MethodsEach test surface was inoculated with known levels of vegetative bacteria (106 cfu/cm2), C. difficile spores (102-106 cfu/cm2) or Adenovirus (109 viral genomes), placed in the Nanoclave Cabinet and exposed for up to 6 minutes to the UV-C light source. Survival of bacterial contaminants was determined via conventional cultivation techniques. Degradation of viral DNA was determined via PCR. Results were compared to the number of colonies or level of DNA recovered from non-exposed control surfaces. Experiments were repeated to incorporate organic soils and to compare the efficacy of the Nanoclave Cabinet to that of antimicrobial wipes.ResultsAfter exposing 8 common non-critical patient care items to two 30-second UV-C irradiation cycles, bacterial numbers on 40 of 51 target sites were consistently reduced to below detectable levels (≥ 4.7 log10 reduction). Bacterial load was reduced but still persisted on other sites. Objects that proved difficult to disinfect using the Nanoclave Cabinet (e.g. blood pressure cuff) were also difficult to disinfect using antimicrobial wipes. The efficacy of the Nanoclave Cabinet was not affected by the presence of organic soils. Clostridium difficile spores were more resistant to UV-C irradiation than vegetative bacteria. However, two 60-second irradiation cycles were sufficient to reduce the number of surface-associated spores from 103 cfu/cm2 to below detectable levels. A 3 log10 reduction in detectable Adenovirus DNA was achieved within 3 minutes; after 6 minutes, viral DNA was undetectable.ConclusionThe results of this study suggest that the Nanoclave Cabinet can provide rapid and effective disinfection of some patient-related equipment. However, laboratory studies do not necessarily replicate ‘in-use’ conditions and further tests are required to assess the usability, acceptability and relative performance of the Nanoclave Cabinet when used in situ.

Routine monitoring of adenovirus and norovirus within the health care environment

This study investigated the presence of adenovirus and norovirus on ward surfaces using real-time polymerase chain reaction (PCR) to assist in the development of evidence-based infection control policy. Screening was carried out weekly for 6 months in the common areas of 2 pediatric wards. Additionally, a one-off screening was undertaken for adenovirus and norovirus on a day unit and for adenovirus only in patient cubicles while occupied. Over the 6-month screening of common areas, 2.4% of samples were positive for adenovirus or norovirus. In rooms occupied with adenovirus-infected children, all cubicle screening sites and almost all swabs were contaminated with adenovirus. In the day unit, 13% of samples were positive. Cleaning and environmental interaction strategies must therefore be designed to control nosocomial transmission of viruses outside of outbreak scenarios.

Septicaemia due to enteric organisms is a later event in surgical infants requiring parenteral nutrition.

INTRODUCTION The purpose of this study was to determine whether, in surgical infants requiring parenteral nutrition (PN), septicaemia due to enterococci or Gram-negative bacilli occurs later than septicaemia due to coagulase-negative staphylococci (CNS). PATIENTS/MATERIAL AND METHODS We retrospectively studied 112 consecutive surgical infants (corrected gestational age up to 3 months) receiving PN for at least 5 days for congenital or acquired intestinal anomalies over a 2-year period (July 2007-June 2009). Data collected included diagnosis, duration of PN, episodes of septicaemia (defined as growth of bacteria from blood culture), and organisms cultured. We compared the time to first occurrence of septicaemia due to CNS with the times to first occurrence of septicaemia due to enterococci, Gram-negative bacilli, or other micro-organisms, using Kruskal-Wallis nonparametric ANOVA test and Dunns multiple comparisons test. Data are given as median (range). RESULTS 31 patients (28%) had a total of 65 episodes of septicaemia. Septicaemia due to CNS was most common, occurring in 22% of patients, after 17 days (1-239) of PN. Septicaemia due to enteric organisms was less common and occurred significantly later, at 59 (24-103) days for enterococci (p<0.01), and at 55 (30-106) days for Gram-negative bacilli (p<0.05). CONCLUSIONS Septicaemia due to enterococci or Gram-negative bacilli occurs later in the course of PN than septicaemia due to CNS, in surgical infants. This suggests that these infants become more vulnerable to the translocation of enteric micro-organisms after a longer period of parenteral nutrition.

Biochemical and microbial contamination of surgical devices: A quantitative analysis

Reusable devices are required to be safety processed prior to patient use, including cleaning and disinfection and sterilization. In developing and testing cleaning processes, it is important to understand the levels of soils typically present on devices after surgical use. Previous soil investigations have focused on microbial contamination levels; less is known about biochemical contamination. In this study, microbial and biochemical contamination on a range of surgical instrumentation after patient use were investigated. Analysis included bacteria levels, total organic carbon, protein, and hemoglobin. The highest levels of soil contamination were caused by protein, in contrast with bacteria levels being a minor component of instrument soiling. This study provides a better understanding of the microbial and biochemical levels of soils that are typically present in used surgical devices. These levels can be used to develop artificial test soils for testing cleaning efficacy under laboratory conditions and to further evaluate patient risks from inadequate cleaning.

Healthcare Environments and Spatial Variability of Healthcare Associated Infection Risk: Cross-Sectional Surveys

Prevalence of healthcare associated infections remains high in patients in intensive care units (ICU), estimated at 23.4% in 2011. It is important to reduce the overall risk while minimizing the cost and disruption to service provision by targeted infection control interventions. The aim of this study was to develop a monitoring tool to analyze the spatial variability of bacteriological contamination within the healthcare environment to assist in the planning of interventions. Within three cross-sectional surveys, in two ICU wards, air and surface samples from different heights and locations were analyzed. Surface sampling was carried out with tryptic Soy Agar contact plates and Total Viable Counts (TVC) were calculated at 48hrs (incubation at 37°C). TVCs were analyzed using Poisson Generalized Additive Mixed Model for surface type analysis, and for spatial analysis. Through three cross-sectional survey, 370 samples were collected. Contamination varied from place-to-place, height-to-height, and by surface type. Hard-to-reach surfaces, such as bed wheels and floor area under beds, were generally more contaminated, but the height level at which maximal TVCs were found changed between cross-sectional surveys. Bedside locations and bed occupation were risk factors for contamination. Air sampling identified clusters of contamination around the nursing station and surface sampling identified contamination clusters at numerous bed locations. By investigating dynamic hospital wards, the methodology employed in this study will be useful to monitor contamination variability within the healthcare environment and should help to assist in the planning of interventions.

Can Clean-Room Particle Counters be Used as an Infection Control Tool in Hospital Operating Theatres?

Current UK guidelines for the commissioning of hospital operating theatres rely on air-flow checks, identification of “short-circuits” and measurement of airborne microbiological levels under design conditions when the theatre is idle. There is currently no guideline for infection control teams to investigate theatres when an increased infection risk is suspected. This study aims to examine the use of clean-room particle counters as an infection control tool by monitoring particle profiles in air as a surrogate for infectious particles. Particle counters (three- and six-channel) were used to simultaneously measure particle concentrations at the theatre inlet area, two outlets and bed area, under design and working conditions. A significant increase in particles of all size ranges (0.3 to >10 µm diameter) was observed when people were introduced. Particle distribution was uneven, with response to environmental changes different at the two outlets. Removal efficiency varied from 52–100%, due to the introduction of particles to the theatre. Within the bed area, significantly different concentrations were measured under design and working conditions; corresponding microbiological samples indicated an associated increase in airborne bacteria. We concluded that particle counters can be used in some aspects of infection control, although more studies are required to fully explore their potential.