Mari Kanerva

Disease burden of Puumala virus infections, 1995-2008

Puumala virus (PUUV) causes mild haemorrhagic fever with renal syndrome, a rodent-borne zoonosis. To evaluate the disease burden of PUUV infections in Finland, we analysed data reported by laboratories to the National Infectious Disease Registry during 1995-2008 and compared these with data from other national registries (death, 1998-2007; hospital discharge, 1996-2007; occupational diseases, 1995-2006). A total of 22,681 cases were reported (average annual incidence 31/100,000 population); 85% were in persons aged 20-64 years and 62% were males. There was an increasing trend in incidence, and the rates varied widely by season and region. We observed 13 deaths attributable to PUUV infection (case-fatality proportion 0.08%). Of all cases, 9599 (52%) were hospitalized. Only 590 cases (3%) were registered as occupational disease, of which most were related to farming and forestry. The wide seasonal and geographical variation is probably related to rodent density and human behaviour.

Healthcare-associated infections in Finnish acute care hospitals: a national prevalence survey, 2005

The objectives of the first national prevalence survey on healthcare-associated infections (HAIs) in Finland were to assess the extent of HAI, distribution of HAI types, causative organisms, prevalence of predisposing factors and use of antimicrobial agents. The voluntary survey was performed during February-March 2005 in 30 hospitals, including tertiary and secondary care hospitals and 10 (25%) other acute care hospitals in the country. The overall prevalence of HAI was 8.5% (703/8234). Surgical site infection was the most common HAI (29%), followed by urinary tract infection (19%) and primary bloodstream infection or clinical sepsis (17%). HAI prevalence was higher in males, among intensive care and surgical patients, and increased with age and severity of underlying illness. The most common causative organisms, identified in 56% (398/703) of patients with HAIs, were Escherichia coli (13%), Staphylococcus aureus (10%) and Enterococcus faecalis (9%). HAIs caused by multi-resistant microbes were rare (N = 6). A total of 122 patients were treated in contact isolation due to the carriage of multi-resistant microbes. At the time of the survey, 19% of patients had a urinary catheter, 6% central venous line and 1% were ventilated. Antimicrobial treatment was given to 39% of patients. These results can be used for prioritising infection control measures and planning more detailed incidence surveillance of HAI. The survey was a useful tool to increase the awareness of HAI in participating hospitals and to train infection control staff in diagnosing HAIs.

Prolonged norovirus outbreak in a Finnish tertiary care hospital caused by GII.4-2006b subvariants

Norovirus outbreaks are difficult to control in hospitals. Cohorting and contact isolation, disinfective surface cleaning and hand hygiene are key elements in outbreak control. A new norovirus variant, GII.4.-2006b, spreading across many continents, caused an exceptionally long epidemic period in Finland, from November 2006 to June 2007. Here, we describe the clinical and molecular characteristics of a norovirus outbreak in a large tertiary care hospital in Finland. Altogether 240 (18%) patients and 205 (19%) healthcare workers fell ill in the 504 bedded main building of Helsinki University Central Hospital during December 2006 to May 2007. The epidemic curve had three peaks in January, February and April, and different wards were affected each time. During the outbreak, 502 patient stool specimens were tested for norovirus RNA, 181 (36%) of which were positive. Molecular analysis of 48 positive specimens revealed three main subvariants of GII.4.-2006b circulating temporally within distinct wards. Of all microbiologically confirmed cases, 121 (67%) were nosocomial and nine (5%) died within 30 days of diagnosis. Molecular analysis suggested that the three main GII.4-2006b subvariants entered the hospital with gastroenteritis patients, and the nosocomial spread within wards coincided with the epidemic peaks. Active control measures, including temporary closure of the wards, ultimately confined the single-ward outbreaks. A prolonged outbreak in the community was probably the source for the prolonged outbreak period in the hospital.

Human Cases of Methicillin-Resistant Staphylococcus aureus CC398, Finland

Nationwide surveillance identified 10 human isolates of methicillin-resistant Staphylococcus aureus clonal complex (CC) 398. Further typing in comparison with animal isolates identified 4 clusters: 1 related to a horse epidemic and 3 to persons who had no direct contact with animals or each other. These findings may indicate unrecognized community transmission.

Estimating the burden of healthcare-associated infections caused by selected multidrug-resistant bacteria Finland, 2010

BackgroundKnowledge of the burden of healthcare-associated infections (HAI) and antibiotic resistance is important for resource allocation in infection control. Although national surveillance networks do not routinely cover all HAIs due to multidrug-resistant bacteria, estimates are nevertheless possible: in the EU, 25,000 patients die from such infections annually. We assessed the burden of HAIs due to multidrug-resistant bacteria in Finland in 2010.MethodsBy combining data from the National Infectious Disease Registry on the numbers of bacteremias caused by Staphylococcus aureus, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Pseudomonas aeruginosa and Acinetobacter spp., and susceptibility data from the National Antimicrobial Resistance Network and the Finnish Hospital Infection Program, we assessed the numbers of healthcare-associated bacteremias due to selected multidrug-resistant bacteria. We estimated the number of pneumonias, surgical site and urinary tract infections by applying the ratio of these infections in the first national prevalence survey for HAI in 2005. Attributable HAI mortality (3.2%) was also derived from the prevalence survey.ResultsThe estimated annual number of the most common HAIs due to the selected multidrug-resistant bacteria was 2804 (530 HAIs per million), 6% of all HAIs in Finnish acute care hospitals. The number of attributable deaths was 89 (18 per million).ConclusionsResources for infection control should be allocated not only in screening and isolation of carriers of multidrug-resistant bacteria, even when they are causing a small proportion of all HAIs, but also in preventing all clinical infections.

Interhospital differences and case-mix in a nationwide prevalence survey.

A prevalence survey is a time-saving and useful tool for obtaining an overview of healthcare-associated infection (HCAI) either in a single hospital or nationally. Direct comparison of prevalence rates is difficult. We evaluated the impact of case-mix adjustment on hospital-specific prevalences. All five tertiary care, all 15 secondary care and 10 (25% of 40) other acute care hospitals took part in the first national prevalence survey in Finland in 2005. US Centers for Disease Control and Prevention criteria served to define HCAI. The information collected included demographic characteristics, severity of the underlying disease, use of catheters and a respirator, and previous surgery. Patients with HCAI related to another hospital were excluded. Case-mix-adjusted HCAI prevalences were calculated by using a multivariate logistic regression model for HCAI risk and an indirect standardisation method. Altogether, 587 (7.2%) of 8118 adult patients had at least one infection; hospital-specific prevalences ranged between 1.9% and 12.6%. Risk factors for HCAI that were previously known or identified by univariate analysis (age, male gender, intensive care, high Charlson comorbidity and McCabe indices, respirator, central venous or urinary catheters, and surgery during stay) were included in the multivariate analysis for standardisation. Case-mix-adjusted prevalences varied between 2.6% and 17.0%, and ranked the hospitals differently from the observed rates. In 11 (38%) hospitals, the observed prevalence rank was lower than predicted by the case-mix-adjusted figure. Case-mix should be taken into consideration in the interhospital comparison of prevalence rates.

Churg-strauss syndrome as an unusual aetiology of stroke with haemorrhagic transformation in a patient with no cardiovascular risk factors.

Background: We present here a case of haemorrhagic brain infarction in a middle-aged and physically active male, who had never smoked. This case report aims to remind the internist and neurologist to bear in mind unusual aetiologies of brain infarcts in patients without classical cardiovascular risk factors. Case Description: A 49-year-old male with pulmonary asthma and a prior history of nasal polyps had a wake-up stroke with left-sided symptoms and speech disturbance. A head MRI and MR angiography revealed a recent haemorrhagic infarct in the right putamen and corona radiata. The left hemiparesis progressed to sensory-motor hemiplegia on the 4th day. In the head CT, it was shown that the haemorrhagic infarct had progressed to a large haematoma. A pansinusitis was also diagnosed. The aetiological investigations revealed a minor atrial septal defect (ASD) with shunting and a heterozygotic clotting factor V R506Q mutation. A remarkable blood eosinophilia of 9.80 E9/l (42%) together with fever, sinusitis, wide-spread bilateral nodular pulmonary infiltrates that did not respond to wide-spectrum antimicrobial treatment, positive anti-neutrophilic cytoplasmic antibodies, a high myeloperoxidase antibody level and slightly positive anti-proteinase 3 antibodies suggested the diagnosis of Churg-Strauss syndrome. These inflammatory symptoms and findings promptly responded to treatment with corticosteroids and cyclophosphamide. Conclusions: Even after the concomitant findings of the low risk factors, i.e. small ASD and heterozygotic clotting factor mutation, continued search for the final aetiology of stroke revealed Churg-Strauss syndrome, which was the key to the treatment.

Risk factors for death in a cohort of patients with and without healthcare-associated infections in Finnish acute care hospitals

We evaluated risk factors for death among hospitalised patients with healthcare-associated infections (HCAIs) using the McCabe classification and Charlson index to predict mortality. The study consisted of a cohort of 703 patients with HCAIs and 7531 patients without HCAI in acute care hospitals participating in the Finnish national prevalence survey in 2005. We used Centers for Disease Control and Prevention definitions for HCAIs and recorded the McCabe classification for comorbidity. We used the date from the prevalence survey and the patients national identity code in order to retrieve data from the National Hospital Discharge Registry on discharge diagnoses (International Classification of Diseases-10 codes) for the Charlson index and the dates of death from the National Population Information System. Of all inpatients, 425 (5.2%) died within 28 days from the prevalence survey date; the death rate was higher in HCAI patients than in those without HCAI (9.8% vs 4.7%, P<0.001). In the multivariate regression analysis age >65 years, intensive care, McCabe classification and Charlson index, gastrointestinal system infection and pneumonia/other lower respiratory tract infections were independent predictors for death. The survival analysis, when adjusted by McCabe class or Charlson index, showed that HCAI reduced survival only among patients without severe underlying diseases. Certain types of HCAI increased the risk of death. The McCabe classification had advantages over the Charlson index as a predictor of death, because it was easier to collect from a prevalence survey.

Regional differences in Clostridium difficile infections in relation to fluoroquinolone and proton pump inhibitor use, Finland, 2008-2011

Abstract Background: Several antimicrobial agents and proton pump inhibitors (PPIs) have been identified as risk factors for Clostridium difficile infections (CDIs). Nationwide laboratory-based surveillance of CDIs in Finland since 2008 has shown variation in regional CDI rates. We evaluated whether regional differences in CDI rates were associated with antibacterial and PPI use. Methods: Data on mean annual incidence rates of CDIs during 2008–2011 in 21 healthcare districts (HDs) were obtained from the National Infectious Disease Register, consumption (median annual use) of antimicrobials and PPIs from the Finnish Medical Agency, availability of molecular diagnostics by a laboratory survey and data on ribotypes from the national reference laboratory. The association over the 4 years was measured by incidence rate ratio (IRR) and we performed both bivariate and multivariate analyses. Results: During 2008–2011, PPI use increased 27% but fluoroquinolone use was stable. The level of fluoroquinolone use was strongly associated with the mean annual CDI incidence rate in different HDs over the 4-year period, but PPI use had less effect. The molecular diagnostics methodology and PCR ribotype 027 were not independently associated with CDI rate. The final multivariable model only included fluoroquinolone and PPI use; IRR for fluoroquinolones was 2.20 (95% confidence interval (CI), 1.32–3.67; p = 0.003). Conclusions: Fluoroquinolone use may play a role in regional differences in CDI rates. Although the use has not recently increased, regionally targeted antimicrobial stewardship campaigns promoting appropriate use of fluoroquinolones should still be encouraged since they may decrease the incidence of CDIs.

Coincidental detection of the first outbreak of carbapenemase-producing Klebsiella pneumoniae colonisation in a primary care hospital, Finland, 2013.

In Finland, occurrence of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP) has previously been sporadic and related to travel. We describe the first outbreak of colonisation with KPC-KP strain ST512; it affected nine patients in a 137-bed primary care hospital. The index case was detected by chance when a non-prescribed urine culture was taken from an asymptomatic patient with suprapubic urinary catheter in June 2013. Thereafter, all patients on the 38-bed ward were screened until two screening rounds were negative and extensive control measures were performed. Eight additional KPC-KP-carriers were found, and the highest prevalence of carriers on the ward was nine of 38. All other patients hospitalised on the outbreak ward between 1 May and 10 June and 101 former roommates of KPC-KP carriers since January had negative screening results. Two screening rounds on the hospitals other wards were negative. No link to travel abroad was detected. Compared with non-carriers, but without statistical significance, KPC-KP carriers were older (83 vs 76 years) and had more often received antimicrobial treatment within the three months before screening (9/9 vs 90/133). No clinical infections occurred during the six-month follow-up. Early detection, prompt control measures and repetitive screening were crucial in controlling the outbreak.