M. Morris-Downes

Secular Trends in Nosocomial Bloodstream Infections: Antibiotic-Resistant Bacteria Increase the Total Burden of Infection

BACKGROUND It is unknown whether rising incidence rates of nosocomial bloodstream infections (BSIs) caused by antibiotic-resistant bacteria (ARB) replace antibiotic-susceptible bacteria (ASB), leaving the total BSI rate unaffected. METHODS We investigated temporal trends in annual incidence densities (events per 100 000 patient-days) of nosocomial BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA), ARB other than MRSA, and ASB in 7 ARB-endemic and 7 ARB-nonendemic hospitals between 1998 and 2007. RESULTS 33 130 nosocomial BSIs (14% caused by ARB) yielded 36 679 microorganisms. From 1998 to 2007, the MRSA incidence density increased from 0.2 to 0.7 (annual increase, 22%) in ARB-nonendemic hospitals, and from 3.1 to 11.7 (annual increase, 10%) in ARB-endemic hospitals (P = .2), increasing the incidence density difference between ARB-endemic and ARB-nonendemic hospitals from 2.9 to 11.0. The non-MRSA ARB incidence density increased from 2.8 to 4.1 (annual increase, 5%) in ARB-nonendemic hospitals, and from 1.5 to 17.4 (annual increase, 22%) in ARB-endemic hospitals (P < .001), changing the incidence density difference from -1.3 to 13.3. Trends in ASB incidence densities were similar in both groups (P = .7). With annual increases of 3.8% and 5.4% of all nosocomial BSIs in ARB-nonendemic and ARB-endemic hospitals, respectively (P < .001), the overall incidence density difference of 3.8 increased to 24.4. CONCLUSIONS Increased nosocomial BSI rates due to ARB occur in addition to infections caused by ASB, increasing the total burden of disease. Hospitals with high ARB infection rates in 2005 had an excess burden of BSI of 20.6 per 100 000 patient-days in a 10-year period, mainly caused by infections with ARB.

Infection due to C. difficile ribotype 078: first report of cases in the Republic of Ireland

Clostridium difficile is an important healthcare-associated pathogen. Hypervirulent strains such as those belonging to ribotype 027 have been widely reported in recent years. A second strain associated with hypervirulence is ribotype 078 and the prevalence of Clostridium difficile infection (CDI) due to this ribotype appears to be increasing. This report describes an outbreak, in which 15cases of CDI due to ribotype 078 were detected in an Irish hospital and from a nursing home in the hospitals catchment area. C. difficile ribotype 078 accounted for 15% of total isolates submitted for ribotyping. The average age of patients with CDI due to ribotype 078 was 76 years. Forty-six percent of patients experienced recurrence of symptoms within eight weeks of diagnosis and CDI was felt to have directly contributed to five of the eight deaths. Use of enhanced DNA fingerprinting identified clusters within the 15 cases and suggested hitherto unrecognised links between some patients with CDI. Such approaches offer the promise to delineate common sources and transmission routes for C. difficile.

Inter-hospital outbreak of Klebsiella pneumoniae producing KPC-2 carbapenemase in Ireland

OBJECTIVES To describe an outbreak of KPC-2-producing Klebsiella pneumoniae with inter-hospital spread and measures taken to control transmission. METHODS Between January and March 2011, 13 K. pneumoniae isolates were collected from nine patients at hospital A and two patients at hospital B. Meropenem, imipenem and ertapenem MICs were determined by Etest, carbapenemase production was confirmed by the modified Hodge method and by a disc synergy test, and confirmed carbapenemase producers were tested for the presence of carbapenemase-encoding genes by PCR. PFGE, plasmid analysis, multilocus variable-number tandem-repeat analysis (MLVA) and multilocus sequence typing (MLST) analysis were performed on all or a subset of isolates. RESULTS Meropenem, imipenem and ertapenem MICs were 4 to >32, 8-32 and >16 mg/L, respectively. PCR and sequencing confirmed the presence of bla(KPC-2). PFGE identified four distinguishable (≥88%) pulsed-field profiles (PFPs). Isolates distinguishable by PFGE had identical MLVA profiles, and MLST analysis indicated all isolates belonged to the ST258 clone. Stringent infection prevention and control measures were implemented. Over a period of almost 8 months no further carbapenemase-producing Enterobacteriaceae (CPE) were isolated. However, KPC-2-producing K. pneumoniae was detected in two further patients in hospital A in August (PFP indistinguishable from previous isolates) and October 2011 (PFP similar to but distinguishable from previous isolates). CONCLUSIONS Stringent infection prevention and control measures help contain CPE in the healthcare setting; however, in the case of hospital A, where CPE appears to be established in the population served, it may be virtually impossible to achieve eradication or avoid reintroduction into the hospital.

Surveillance and endemic vancomycin-resistant enterococci: some success in control is possible

Vancomycin-resistant enterococci (VRE) are prevalent in many Irish hospitals. We analysed surveillance data from 2001 to 2008 in a centre where VRE is endemic. All clinically significant enterococci were tested for susceptibility to vancomycin. All intensive care unit admissions were screened on admission and weekly thereafter. Interventions included isolating/cohorting VRE patients, monthly prevalence surveys of VRE patients, the introduction of an electronic alert system, programmes to improve hand and environmental hygiene, and the appointment of an antibiotic pharmacist. There was a significant increase in the number of positive VRE screening samples from 2001 (1.96 patients with positive VRE screens per 10 000 bed-days) to 2006 (4.98 per 10 000 bed-days) (P < or = 0.001) with a decrease in 2007 (3.18 per 10 000 bed-days) (P < or = 0.01). The number of VRE bloodstream infections (BSI) increased from 0.09 BSI per 10 000 bed-days in 2001 to 0.78 per 10 000 bed-days in 2005 (P < or = 0.001) but decreased subsequently. Linear regression analysis indicated a significant association between new cases of VRE and non-isolated VRE patients, especially between May 2005 and December 2006 [P=0.009; 95% confidence interval (CI): 0.08-0.46] and between May 2005 and December 2008 (P = 0.008; 95% CI: 0.06-0.46). Routine surveillance for VRE together with other measures can control VRE BSI and colonisation, even where VRE is endemic, and where facilities are constrained.

Role of patient awareness in prevention of peripheral vascular catheter-related bloodstream infection.

Infection • Author(s): Seamus Mark McHugh , MB, BCh, BAO, MRCSI, Mark Anthony Corrigan , MD, MRCSI, Borislav D. Dimitrov , PhD, Margaret Morris‐Downes , PhD, Fidelma Fitzpatrick , MD, Seamus Cowman , MSc, PhD, Sean Tierney , BSc, MCh, FRCSI, Arnold D. K. Hill , MCh, FRCSI, Hilary Humphreys , MD, FRCPI Source: Infection Control and Hospital Epidemiology, Vol. 32, No. 1 (January 2011), pp. 95-96 Published by: The University of Chicago Press on behalf of The Society for Healthcare Epidemiology of America Stable URL: http://www.jstor.org/stable/10.1086/657630 . Accessed: 11/01/2011 10:59