Enhanced Tracking of Nosocomial Transmission of Endemic Sequence Type 22 Methicillin-Resistant Staphylococcus aureus Type IV Isolates among Patients and Environmental Sites by Use of Whole-Genome Sequencing.

Whole-genome sequencing (WGS) of 41 patient and environmental sequence type 22 methicillin-resistant Staphylococcus aureus staphylococcal cassette chromosome mec type IV (ST22-MRSA-IV) isolates recovered over 6 weeks in one acute hospital ward in Dublin, Ireland, where ST22-MRSA IV is endemic, revealed 228 pairwise combinations differing by <40 single nucleotide variants corresponding to potential cross-transmission events (CTEs). In contrast, 15 pairwise combinations of isolates representing five CTEs were previously identified by conventional molecular epidemiological typing. WGS enhanced ST22-MRSA-IV tracking and highlighted potential transmission of MRSA via the hospital environment.

Pilot evaluation of a ward-based automated hand hygiene training system.

A novel artificial intelligence (AI) system (SureWash; GLANTA, Dublin, Ireland) was placed on a ward with 45 staff members for two 6-day periods to automatically assess hand hygiene technique and the potential effectiveness of the automated training system. Two human reviewers assessed videos from 50 hand hygiene events with an interrater reliability (IIR) of 88% (44/50). The IIR was 88% (44/50) for the human reviewers and 80% (40/50) for the software. This study also investigated the poses missed and the impact of feedback on participation (+113%), duration (+11%), and technique (+2.23%). Our findings showed significant correlation between the human raters and the computer, demonstrating for the first time in a clinical setting the potential use of this type of AI technology in hand hygiene training.

Evaluation of screening risk and nonrisk patients for methicillin-resistant Staphylococcus aureus on admission in an acute care hospital.

BACKGROUND: Screening for methicillin-resistant Staphylocccus aureus (MRSA) is advocated as part of control measures, but screening all patients on admission to hospital may not be cost-effective. OBJECTIVE: Our objective was to evaluate the additional yield of screening all patients on admission compared with only patients with risk factors and to assess cost aspects. METHODS: A prospective, nonrandomized observational study of screening nonrisk patients ≤72 hours of admission compared with only screening patients with risk factors over 3 years in a tertiary referral hospital was conducted. We also assessed the costs of screening both groups. RESULTS: A total of 48 of 892 (5%) patients was MRSA positive; 28 of 314 (9%) during year 1, 12 of 257 (5%) during year 2, and 8 of 321 (2%) during year 3. There were significantly fewer MRSA-positive patients among nonrisk compared with MRSA-risk patients: 4 of 340 (1%) versus 44 of 552 (8%), P ≤ .0001, respectively. However, screening nonrisk patients increased the number of screening samples by 62% with a proportionate increase in the costs of screening. A backward stepwise logistic regression model identified age > 70 years, diagnosis of chronic pulmonary disease, previous MRSA infection, and admission to hospital during the previous 18 months as the most important independent predictors to discriminate between MRSA-positive and MRSA-negative patients on admission (94.3% accuracy, P < .001). CONCLUSION: Screening patients without risk factors increased the number of screenings and costs but resulted in few additional cases being detected. In a hospital where MRSA is endemic, targeted screening of at-risk patients on admission remains the most efficient strategy for the early identification of MRSA-positive patients.

Enhanced discrimination of highly clonal ST22-methicillin-resistant Staphylococcus aureus IV isolates achieved by combining spa, dru, and pulsed-field gel electrophoresis typing data.

ST22-methicillin-resistant Staphylococcus aureus type IV (ST22-MRSA-IV) is endemic in Irish hospitals and is designated antibiogram-resistogram type-pulsed-field group (AR-PFG) 06-01. Isolates of this highly clonal strain exhibit limited numbers of pulsed-field gel electrophoresis (PFGE) patterns and spa types. This study investigated whether combining PFGE and spa typing with DNA sequencing of the staphylococcal cassette chromosome mec element (SCCmec)-associated direct repeat unit (dru typing) would improve isolate discrimination. A total of 173 MRSA isolates recovered in one Irish hospital during periods in 2007 and 2008 were investigated using antibiogram-resistogram (AR), PFGE, spa, dru, and SCCmec typing. Isolates representative of each of the 17 pulsed-field group 01 (PFG-01) spa types identified underwent multilocus sequence typing, and all isolates were ST22. Ninety-seven percent of isolates (168 of 173) exhibited AR-PFG 06-01 or closely related AR patterns, and 163 of these isolates harbored SCCmec type IVh. The combination of PFGE, spa, and dru typing methods significantly improved discrimination of the 168 PFG-01 isolates, yielding 65 type combinations with a Simpson's index of diversity (SID) of 96.53, compared to (i) pairwise combinations of spa and dru typing, spa and PFGE typing, and dru and PFGE typing, which yielded 37, 44, and 43 type combinations with SIDs of 90.84, 91.00, and 93.57, respectively, or (ii) individual spa, dru, and PFGE typing methods, which yielded 17, 17, and 21 types with SIDs of 66.9, 77.83, and 81.34, respectively. Analysis of epidemiological information for a subset of PFG-01 isolates validated the relationships inferred using combined PFGE, spa, and dru typing data. This approach significantly enhances discrimination of ST22-MRSA-IV isolates and could be applied to epidemiological investigations of other highly clonal MRSA strains.

The effect of rapid screening for methicillin-resistant Staphylococcus aureus (MRSA) on the identification and earlier isolation of MRSA-positive patients.

OBJECTIVES: (1) To determine whether rapid screening with polymerase chain reaction (PCR) assays leads to the earlier isolation of patients at risk for methicillin-resistant Staphylococcus aureus (MRSA) colonization, (2) to assess compliance with routine MRSA screening protocols, (3) to confirm the diagnostic accuracy of the Xpert MRSA real-time PCR assay (Cepheid) by comparison with culture, and (4) to compare turnaround times for PCR assay results with those for culture results. DESIGN: Before-and-after study conducted in a 700-bed acute tertiary care referral hospital. Study periods were (1) a 5-week period before PCR testing began, (2) a 10-week period when the PCR assay was used, and (3) a 5-week period after PCR testing was discontinued. RESULTS: Among 489 at-risk patients, MRSA was isolated from 20 (33%) of 60 patients during period 1, 77 (22%) of 349 patients during period 2, and 18 (23%) of 80 patients during period 3. Twenty-two (27%) of 82 at-risk patients were not screened during period 1, compared with 40 (10%) of 389 at-risk patients not screened during period 2 (P < .001). More MRSA-positive patients were preemptively isolated during periods 1 and 3 compared with period 2 (34 [24%] of 140 vs 28 [8%] of 389; P < .001); however, more MRSA-positive patients were isolated after notification of MRSA-positive results during period 2 (47 [13%] of 349) compared with periods 1 and 3 (2 [1%] of 140; P < .001). The sensitivity, specificity, positive predictive value, and negative predictive value of the PCR assay were 95%, 97%, 82%, and 99%, respectively. The mean turnaround time from receipt of specimens in the laboratory to PCR assay result was 2.6 hours. CONCLUSIONS: Rapid screening with the Xpert MRSA PCR assay facilitated compliance with screening policies and the earlier isolation of MRSA-positive patients. Discrepant results confirm that PCR testing should be used as a screening tool rather than as a diagnostic tool.

A survey of nurses' assessment of peripheral intravenous catheters.

The purpose of this survey was to improve nursing care of patients with peripheral intravenous catheters (PVCs), focusing on assessment of the PVC site for infection. The survey was conducted in 20 wards by an infection control nurse (ICN), recording data on assessment, site infection and removal/resiting of PVCs. Nursing staff were interviewed on assessment of the PVC site and nursing interventions were recorded. A total of 554 PVCs in 397 patients were surveyed of which 28 (5%) had site infection. There was no related bloodstream infection (BSI). Overall, PVCs were assessed 450 (81%) times by nurses. Malfunction was reported 95 (17%) times, pain 28 (5%) times and pyrexia 10 (2%) times. Characteristics that showed significant difference between 28 infected and 526 non-infected PVCs included when nurses assessed PVCs as infected, and nurses' intervention for PVCs inserted for 1-3 days' duration. Other characteristics were resiting PVCs when associated with malfunction and also resiting because of pain. The involvement of the ICN was likely to have contributed to the low infection rate. While not conclusive this survey identified characteristics between infected and non-infected PVCs that may have been associated with this low infection rate, namely, nurses' overall intervention in PVC care and assessment that is focused on identifying infection, and resiting for malfunction and pain. These are simple assessment and intervention measures that should not require the assignment of a dedicated ICN, but which are within the capabilities of all healthcare workers entrusted with PVC care.

Sixteen years' surveillance of surgical sites in an Irish acute-care hospital.

OBJECTIVE: To report a program of continuous surveillance of surgical-site infections (SSIs) using basic surveillance methods. DESIGN: Analysis of routine prospective surveillance data. SETTING: Two hospitals in Ireland (300 and 350 beds) that merged and moved to a new 650-bed hospital in 1987. PATIENTS: 59,335 surgical sites of postoperative patients. INTERVENTIONS: Surgical sites were surveyed by one infection control nurse and SSI rates were produced for selected operations and surgical services. The program was conducted in general accordance with the 1999 HICPAC guidelines, but differed in surveillance strategy. Operations were limited to two to three risk classifications, assigned by the infection control nurse. RESULTS: The overall SSI rate was 4.5%, with 2.4% in clean surgery. Apart from increases in the 3rd, 4th, 13th, and 14th years, rates remained relatively stable during the 16 years. Few significant decreases in SSI rates in surgical services or specific operations were shown, apart from the following: vascular surgery, 8.1% to 5% between the first 8 years and the last 8 years; general surgery services, 9% to 5%, and gynecology, 15.8% to 1.7%, both in the first year compared with in subsequent years; and gastric operations, 21% to 4.3% between the first year and the second year. Organ/space infection was identified in 0.5% of 17,804 operations, including 0.4% meningitis after neurosurgical procedures, 3% graft infections after vascular bypass operations, and 0.2% intra-abdominal infections after abdominal surgery. CONCLUSIONS: With the use of basic principles of surveillance and modest resources, procedure-specific SSI rates were produced, with little significant change during the 16 years. Despite limitations in case-finding, risk stratification, feedback, and surveillance methods, the overall SSI rates were comparable with other published data.