Guidance for the decontamination of intracavity medical devices: the report of a working group of the Healthcare Infection Society.

BACKGROUND: Intracavity medical devices (ICMDs) are used in a wide variety of healthcare settings. The approach to their decontamination and the resources available also differ widely. Their potential for infection transmission is considerable. AIM: To produce a comprehensive risk assessment-based approach to the decontamination of ICMDs, accompanied by an adaptable audit tool.

Whole-Genome Sequencing Reveals the Contribution of Long-Term Carriers in Staphylococcus aureus Outbreak Investigation.

Whole-genome sequencing (WGS) makes it possible to determine the relatedness of bacterial isolates at a high resolution, thereby helping to characterize outbreaks. However, for Staphylococcus aureus, the accumulation of within-host diversity during carriage might limit the interpretation of sequencing data. In this study, we hypothesized the converse, namely, that within-host diversity can in fact be exploited to reveal the involvement of long-term carriers (LTCs) in outbreaks. We analyzed WGS data from 20 historical outbreaks and applied phylogenetic methods to assess genetic relatedness and to estimate the time to most recent common ancestor (TMRCA). The findings were compared with the routine investigation results and epidemiological evidence. Outbreaks with epidemiological evidence for an LTC source had a mean estimated TMRCA (adjusted for outbreak duration) of 243 days (95% highest posterior density interval [HPD], 143 to 343 days) compared with 55 days (95% HPD, 28 to 81 days) for outbreaks lacking epidemiological evidence for an LTC (P = 0.004). A threshold of 156 days predicted LTC involvement with a sensitivity of 0.875 and a specificity of 1. We also found 6/20 outbreaks included isolates with differing antimicrobial susceptibility profiles; however, these had only modestly increased pairwise diversity (mean 17.5 single nucleotide variants [SNVs] [95% confidence interval {CI}, 17.3 to 17.8]) compared with isolates with identical antibiograms (12.7 SNVs [95% CI, 12.5 to 12.8]) (P < 0.0001). Additionally, for 2 outbreaks, WGS identified 1 or more isolates that were genetically distinct despite having the outbreak pulsed-field gel electrophoresis (PFGE) pulsotype. The duration-adjusted TMRCA allowed the involvement of LTCs in outbreaks to be identified and could be used to decide whether screening for long-term carriage (e.g., in health care workers) is warranted. Requiring identical antibiograms to trigger investigation could miss important contributors to outbreaks.

Surveillance of infection associated with external ventricular drains: proposed methodology and results from a pilot study.

BACKGROUND: The insertion of external ventricular drains (EVDs) is necessary in some neurosurgical patients, but increases the risk of meningitis/ventriculitis. While there are well-recognized risk factors, the proportion of patients who develop meningitis/ventriculitis varies partly due to differences in definitions. A multi-disciplinary working group was established to agree definitions for EVD-associated meningitis/ventriculitis, and a surveillance system was piloted in four centres in the UK and Ireland. METHODS: Definitions were agreed based on those published previously and on clinical and microbiological criteria. An agreed dataset was developed to monitor patients after the insertion of an EVD and until the EVD was removed and the microbial aetiology was recorded. FINDINGS: Four neurosurgical centres participated, with 61-564 patients surveyed in each unit. The vast majority of drains were cranial. Intracranial haemorrhage was the most common indication for the EVD insertion. Between 6% and 35% of EVDs were inserted by consultants rather than junior doctors. The proportion of patients who developed meningitis/ventriculitis varied from 3% to 18% and from 4.8 to 12.7/1000 EVD-days. Coagulase-negative staphylococci were the most common microbial causes. CONCLUSIONS: Routine and ongoing monitoring of patients with an EVD in situ to detect meningitis/ventriculitis presents logistical difficulties, and few units do so. This pilot study suggests that a national system of surveillance with agreed definitions and a methodology to enable unit-to-unit comparisons of EVD meningitis/ventriculitis is both necessary and feasible. This will, in turn, inform quality improvement processes leading to the minimization of infection.

Surveillance and management of ventriculitis following neurosurgery.

Ventriculitis is an important complication following neurosurgery and is often associated with the use of an external ventricular drain (EVD). The incidence varies from <5% to 20%, partly due to variations in the definitions used for diagnosis. Staphylococci are the most important causes but the isolation of coagulase-negative staphylococci from a cerebrospinal fluid (CSF) sample needs to be interpreted with caution as it may represent contamination. Risk factors for ventriculitis include advanced age, the duration of EVD placement, the number of manipulations and the presence of intraventricular haemorrhage. Prevention strategies increasingly focus on the implementation of a care bundle that includes aseptic technique at the time of insertion and during any manipulations, skin preparation, prophylactic antibiotics, and appropriate dressings at the site of the EVD. The use of EVDs impregnated with antimicrobial agents is increasing but, whereas some studies show that these are effective, it is not clear whether they provide added benefit when there is compliance with other measures. Antimicrobial treatment is challenging as many widely used agents do not penetrate into the CSF and causative bacteria are increasingly multidrug resistant. Often a combination of high-dose intravenous and intraventricular agents is required, especially for Gram-negative infections. Large trials in this area are challenging to conduct; therefore, to better inform preventive strategies and to optimize management of this important condition, ongoing national surveillance and pooling of data on treatment approaches and outcomes are needed.

Clinical and economic burden of surgical site infection (SSI) and predicted financial consequences of elimination of SSI from an English hospital.

BACKGROUND: Although surgical site infections (SSIs) are known to be associated with increased length of stay (LOS) and additional cost, their impact on the profitability of surgical procedures is unknown. AIM: To determine the clinical and economic burden of SSI over a two-year period and to predict the financial consequences of their elimination. METHODS: SSI surveillance and Patient Level Information and Costing System (PLICS) datasets for patients who underwent major surgical procedures at Plymouth Hospitals NHS Trust between April 2010 and March 2012 were consolidated. The main outcome measures were the attributable postoperative length of stay (LOS), cost, and impact on the margin differential (profitability) of SSI. A secondary outcome was the predicted financial consequence of eliminating all SSIs. FINDINGS: The median additional LOS attributable to SSI was 10 days [95% confidence interval (CI): 7-13 days] and a total of 4694 bed-days were lost over the two-year period. The median additional cost attributable to SSI was £5,239 (95% CI: 4,622-6,719) and the aggregate extra cost over the study period was £2,491,424. After calculating the opportunity cost of eliminating all SSIs that had occurred in the two-year period, the combined overall predicted financial benefit of doing so would have been only £694,007. For seven surgical categories, the hospital would have been financially worse off if it had successfully eliminated all SSIs. CONCLUSION: SSI causes significant clinical and economic burden. Nevertheless the current system of reimbursement provided a financial disincentive to their reduction.

Prolonged outbreak of meticillin-resistant Staphylococcus aureus in a cardiac surgery unit linked to a single colonized healthcare worker.

BACKGROUND: In low- as well as in high-prevalence settings, healthcare workers (HCWs) may be a substantial, under-recognized, reservoir of meticillin-resistant Staphylococcus aureus (MRSA) and an important potential source of transmission to patients. AIM: To report an outbreak of MRSA in a cardiac surgery unit in England over a 10-month period. METHODS: Cases were defined as patients and staff on the cardiac surgery unit from whom the outbreak strain was newly isolated between 20 May 2011 and 16 March 2012. Representative isolates from all cases were characterized by spa-typing, pulsed-field gel electrophoresis and multi-locus variable-number tandem-repeat analysis (MLVA). FINDINGS: Four patients appeared to acquire MRSA during their inpatient stay on the cardiac surgery unit. All four patients and one HCW were found to be carrying an identical epidemic (E)MRSA-15 strain (spa t032, pulsotype A, MLVA profile 16-6-3-1-1-17-1-4). No other members of staff were found to be colonized with MRSA. The colonized HCW was thought to be the source of the outbreak and was decolonized using a combination of nasal mupirocin, chlorhexidine body wash and oral rifampicin and doxycycline. CONCLUSIONS: This report highlights recent changes in the epidemiology of MRSA in England and suggests an important role for colonized HCWs in the transmission of MRSA to patients. Screening HCWs may provide an increasingly valuable strategy in managing linked hospital acquisitions and well-defined outbreaks where initial investigation does not reveal a source.

Compartmentalization of wards to cohort symptomatic patients at the beginning and end of norovirus outbreaks.

BACKGROUND: Outbreaks of norovirus can have a significant operational and financial impact on healthcare establishments. AIM: To assess whether containment of symptomatic patients in single rooms and bays at the beginning and end of norovirus outbreaks reduced the length of bed closure. METHODS: In 2007, we introduced a new strategy to limit the operational impact of hospital outbreaks of norovirus. Early in an outbreak, symptomatic patients were cohorted in single rooms or bays in an attempt to contain the outbreak without closing the entire ward. Once a ward had been closed, and as beds became available through discharges, patients were decanted into single rooms or empty bays with doors to facilitate earlier cleaning and opening of affected areas on the same ward. The impact of these changes was assessed by comparing outbreak data for two periods before and after implementation of the new strategy. FINDINGS: Prior to June 2007, 90% of outbreaks were managed by closure of an entire ward, compared with only 54% from June 2007 onwards. The duration of closure was significantly shorter for bays compared with entire wards, both before (3.5 vs 6, P = 0.0327) and after (3 vs 5, P < 0.0001) June 2007. When considering all outbreaks, there was a significant reduction in duration of closure after the change in strategy (6 vs 5, P = 0.007). CONCLUSION: Using ward compartmentalization to cohort affected patients at the beginning and end of norovirus outbreaks improved the efficiency of outbreak management and reduced operational disruption.

Decontamination of transvaginal ultrasound probes: review of national practice and need for national guidelines.

AIM: To determine the national practice of transvaginal ultrasound (TVUS) probe decontamination in English hospitals and to develop recommendations for guidance. MATERIALS AND METHODS: A literature review was undertaken to clarify best practice and evaluate methods of decontamination of TVUS probes. A questionnaire was developed to ascertain TVUS probe decontamination programmes in current use within English hospitals. This was sent to ultrasound leads of 100 English hospitals; 68 hospitals responded. RESULTS: There is a wide variation in TVUS probe decontamination across English hospitals. Although the majority of respondents (87%, 59/68) reported having clear and practical written guidelines for TVUS decontamination, the frequency, methods, and types of decontamination solutions utilized were widely variable and none meet the standards required to achieve high-level disinfection. CONCLUSION: While the decontamination of other endoluminal medical devices (e.g., flexible endoscopes) is well defined and regulated, the decontamination of TVUS probes has no such guidance. There appears to be incomplete understanding of the level of risk posed by TVUS probes, and in some cases, this has resulted in highly questionable practices regarding TVUS hygiene. There is an urgent need to develop evidence-based national guidance for TVUS probe decontamination.

Guidelines on the facilities required for minor surgical procedures and minimal access interventions.

There have been many changes in healthcare provision in recent years, including the delivery of some surgical services in primary care or in day surgery centres, which were previously provided by acute hospitals. Developments in the fields of interventional radiology and cardiology have further expanded the range and complexity of procedures undertaken in these settings. In the face of these changes there is a need to define from an infection prevention and control perspective the basic physical requirements for facilities in which such surgical procedures may be carried out. Under the auspices of the Healthcare Infection Society, we have developed the following recommendations for those designing new facilities or upgrading existing facilities. These draw upon best practice, available evidence, other guidelines where appropriate, and expert consensus to provide sensible and feasible advice. An attempt is also made to define minimal access interventions and minor surgical procedures. For minimal access interventions, including interventional radiology, new facilities should be mechanically ventilated to achieve 15 air changes per hour but natural ventilation is satisfactory for minor procedures. All procedures should involve a checklist and operators should be appropriately trained. There is also a need for prospective surveillance to accurately determine the post-procedure infection rate. Finally, there is a requirement for appropriate applied research to develop the evidence base required to support subsequent iterations of this guidance.

Impact of preoperative screening for meticillin-resistant Staphylococcus aureus by real-time polymerase chain reaction in patients undergoing cardiac surgery.

We report a significant reduction in the number of surgical site infections (SSIs) due to meticillin-resistant Staphylococcus aureus (MRSA) in patients undergoing cardiac surgery after the introduction of preoperative screening using a same-day polymerase chain reaction (PCR) test. This was an observational cohort study set in a cardiac surgery unit based in southwest England. We studied 1462 patients admitted for cardiac surgery between October 2004 and September 2006. The IDI MRSA PCR test was used preoperatively to screen 765 patients between October 2005 and September 2006. Patients identified as carriers were treated with nasal mupirocin ointment and topical triclosan for five days, with single-dose teicoplanin instead of flucloxacillin as perioperative antibiotic prophylaxis. The rate of SSI following cardiac surgery in this group was compared to 697 patients who underwent surgery without screening between October 2004 and September 2005. After introduction of PCR screening, the overall rate of SSI fell from 3.30% to 2.22% with a significant reduction in the rate of MRSA infections (relative risk reduction: 0.77; 95% confidence interval: 0.056-0.95). PCR screening combined with suppression of MRSA at the time of cardiac surgery is feasible in routine clinical practice and is associated with a significant reduction in subsequent MRSA SSIs.

Effect on MRSA transmission of rapid PCR testing of patients admitted to critical care.

We report a significant reduction in the rate of meticillin-resistant Staphylococcus aureus (MRSA) transmission on a critical care unit when admission screening by culture was replaced with a same-day polymerase chain reaction (PCR) test. This was an observational cohort study, set in a 19-bed mixed medical and surgical adult critical care unit in southwest England. We studied 1305 patients admitted between April 2005 and February 2006. Standard MRSA culture methods were used to screen 612 patients between April 2005 and August 2005, and the IDI MRSA PCR test was used to screen 693 patients between September 2005 and February 2006. Standard infection control precautions were instituted when positive results were obtained by either method. Outcome measures included carriage rate, turnaround time for results and rate of subsequent MRSA transmission on the unit. The overall carriage rate on admission to the unit was 7.0%. Culture results were available in three working days, PCR results within one working day. The mean incidence of MRSA transmission was 13.89/1000 patient days during the culture phase and 4.9/1000 patient days during the PCR phase (relative risk reduction 0.65, 95% CI 0.28-1.07). PCR screening for MRSA on admission to critical care units is feasible in routine clinical practice, provides quicker results than culture-based screening and is associated with a significant reduction in subsequent MRSA transmission.