Colonization with Staphylococcus aureus in Swedish nursing homes: a cross-sectional study

Differences in molecular epidemiology of Staphylococcus aureus and Escherichia coli in nursing home residents and people in unassisted living situations

BACKGROUND

The usefulness of colonization pressure as a working model and proxy for infection transmission is limited due to the inability to grade or quantify the specific risk within environments that are subject to change.

AIM

To elaborate on the colonization pressure model by comparing the molecular epidemiology of two bacteria, Staphylococcus aureus and Escherichia coli, among residents in a nursing home and people in unassisted living situations.

METHODS

A cross-sectional study of 73 elderly residents from a village in south-central Sweden was conducted. Of these, 35 were residents of a nursing home, and 34 lived in an own place of residence in the same geographical area. Samples of two representative bacterial species were collected from multiple body sites and analysed for molecular diversity.

FINDINGS

Combining all body sites, 47% of the participants were colonized with S. aureus and 93% with E. coli. The nursing home group, the group in unassisted living situations, and both units combined, held 16, 17, and 29 different S. aureus spa types, respectively. The corresponding numbers of different E. coli serogenotypes were 34, 28, and 48. Diabetes mellitus was associated with more frequent colonization with S. aureus.

CONCLUSION

The molecular diversity of bacteria found within different forms of accommodation was within the same range. Hospital quality hygiene might have contributed to the absence of homogenization of the molecular diversity within the nursing home group. Diabetes mellitus might have played a role in a patient selection characterized by advanced age.

The general status of patients and limited physical activity as risk factors of Methicillin-resistant Staphylococcus aureus occurrence in long-term care facilities residents in Krakow, Poland

Background

The aim of this study was to investigate the epidemiology and resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolates from long-term care facilities (LTCF) residents and to analyze the potential risk factors for MRSA occurrence, defined as MRSA colonization and/or infection.

Methods

Point prevalence (PPS) and prospective incidence continuous study (CS) was carried out on a group of 193 residents in 2009-2010.

Results

Overall MRSA occurred (with or without infection) among 17.6% of residents. There was 16 cases of infections with SA aetiology, of which 10 (58.8%) were caused by MRSA. The MRSA prevalence in PPS was 12.9%, in CS infection incidence rate was 5.2%. Factors associated with MRSA occurrence were: general status of patients, limited physical activity, wound infections (odds ratio, OR 4.6), ulcers in PPS (OR 2.1), diabetes (OR 1.6), urinary catheterization (OR 1.6) and stool incontinence (OR 1.2).

Conclusions

Our data indicate a need for screening of MRSA before hospitalization or transfer to rehabilitation centres, especially in a group of residents with limitations in physical activity – i.e. with the highest risk of MRSA. Results also suggest the need for contact precautions in patients with high risk of MRSA occurrence, only. Focus on the high-risk population might be a solution for the cost-effective surveillance.

Prevalence and molecular epidemiology of Staphylococcus aureus in Swedish nursing homes - as revealed in the SHADES study

Knowledge of carriage and population dynamics of Staphylococcus aureus is crucial for infection risk assessment and to reveal transmission patterns of strains. We report the prevalence and molecular epidemiology of S. aureus in elderly people (n = 290) living in nursing homes in three cities in the south of Sweden. The overall carriage prevalence rate was 48% when results from nares (31%) and throat (34%) samples were combined. Common spa types were equally distributed but a frequent type, t160, was found only in one of the regions. Carriage of different spa types was detected in 23% of individuals and antimicrobial resistance rates were higher in S. aureus isolates from those carrying more than one spa type. Five of the 21 individuals who carried different spa types were colonized simultaneously with resistant and non-resistant strains. Seventeen per cent of the individuals carried S. aureus of the same spa type on all occasions. Methicillin resistance was not detected. In conclusion we found a high prevalence of S. aureus in this elderly population with a high rate of dual colonization with different spa types. We also found signs of institutional spread of one strain.

Frequency, determinants and prognostic implications of infectious complications after transcatheter aortic valve implantation

In-hospital infection (IHI) after transcatheter aortic valve implantation (TAVI) has received little attention, although it may have a significant effect on outcomes and costs because of prolonged hospital stay. Therefore, the aim of this study was to determine the incidence, type, predictors, and prognostic effects of IHI after TAVI. This study included 298 consecutive patients from 2 centers who underwent TAVI from November 2005 to November 2011. IHI during the hospital stay was defined on the basis of symptoms and signs assessed by the attending physician in the cardiac care unit or medium care unit in combination with all technical examinations performed to confirm infection. IHI after TAVI was observed in 58 patients (19.5%): urinary tract infections in 25 patients (43.1%), pneumonia in 12 patients (20.7%), and access-site infections in 7 patients (12.1%). In 12 patients (20.7%), the site of infection could not be determined, and 2 patients (3.4%) had multiple infection sites. Multivariate analysis revealed that surgical access through the femoral artery was the most important determinant of infection (odds ratio [OR] 4.18, 95% confidence interval [CI] 1.02 to 17.19), followed by perioperative major stroke (OR 3.21, 95% CI 1.01 to 9.52) and overweight (body mass index ≥25 kg/m²; OR 2.27, 95% CI 1.12 to 4.59). The length of hospital stay in patients with IHIs was 15.0 days (interquartile range 8.0 to 22.0) compared with 7.0 days (interquartile range 4.0 to 10.0) in patients without infections (p <0.0001). Kaplan-Meier estimates of survival at 1 year were 76.6% and 74.4% (log-rank, p = 0.61), respectively. Unadjusted and adjusted OR analysis revealed that IHI did not predict mortality at 30 days (OR 1.27, 95% CI 0.49 to 3.30) or at 1 year (hazard ratio 1.24, 95% CI 0.68 to 2.25). In conclusion, IHI occurred in 19.5% of the patients. Patient-related and, more important, procedure-related variables play a role in the occurrence of infection, indicating that improvements in the execution of TAVI may lead to a reduction of this complication.

Close association between oropharyngeal and rhinopharyngeal colonization with Staphylococcus aureus - clues to new insight of MRSA colonization of the oropharynx

This study provides data on prevalence of Staphylococcus aureus in oropharynx, rhinopharynx and vestibulum nasi. Specimens were taken from these three pharyngeal sites in 346 patients and analysed for S. aureus. Abnormal pharyngeal findings and patient histories were recorded. S. aureus was found in 8.1%, 7.2% and 20.2% of all specimens from oropharynx, rhinopharynx and vestibulum nasi, respectively. A strong association between colonization of oropharynx and rhinopharynx was found, especially when vestibulum nasi was not colonized. These findings can be used in development of more effective meticillin-resistant Staphylococcus aureus decolonization regimes.