Impact of Methicillin Resistant Staphylococcus aureus Contact Isolation Units on Medical Care.

2013

Masse V, Valiquette L, Boukhoudmi S, Bonenfant F, Talab Y, Carvalho JC, Alarie I, Carrier N, Farand P.

Source

Infectious Diseases Division, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec, Canada.

Abstract

BACKGROUND:

Patient isolation using contact precautions has gained widespread use to halt MRSA transmission, however supportive data is scarce and concerns regarding patient safety and satisfaction have been raised. At our institution, MRSApatients are isolated on a dedicated ward (cohort isolation), rather than in separate rooms. Our objectives were (1) to determine the proportion of bedside medical visits to patients on an isolation ward, (2) to quantify complications in those patients and (3) to determine if those complications are related to isolation and if they can be prevented.

METHODS:

This retrospective case-control study was performed on the two sites of a tertiary teaching hospital in Sherbrooke, QC, Canada. We matched MRSA patients with an admission diagnosis of heart failure or chronic obstructive pulmonary disease to similar non-isolated controls. The proportion of bedside visits was ascertained through the number of progress notes with subjective elements or with a physical examination. Complications were sought through an extensive file review, and events were analysed according to Baker's CAES causality and preventability scales.

RESULTS:

Overall, 111 patient pairs were analysed (35 with heart failure and 76 with COPD). Isolated patients received less bedside visits (subjective notes/1,000 patient-days: 849.6 983.3, p = 0,001). Attending physicians (454.5 451.4, p = 0,02) and residents (347.0 416.9, p = 0.01) are responsible for this discrepancy, while medical students appear to visit isolated and non-isolated patients equally (116.5 114.9, p = 0.90). Isolated patients showed a tendency towards longer stay and more preventable complications, although no difference in the total number of complications was observed.

CONCLUSION:

Isolated patients have less documented care that suggests less bedside visits from the medical staff, which could hamper the therapeutical relationship. Further studies are needed to explain this finding.

PubMed

Matched-Cohort DNA Microarray Diversity Analysis of Methicillin Sensitive and Methicillin Resistant Staphylococcus aureus Isolates from Hospital Admission Patients.

2012

Ruffing U, Akulenko R, Bischoff M, Helms V, Herrmann M, von Müller L.

Source

Institute of Medical Microbiology and Hygiene, Saarland University Medical Center, Homburg/Saar, Germany.

Abstract

As genotyping of S. aureus is important for epidemiologic research and for hygiene management, methods are required for standardized fast and easily applicable evaluation of closely related epidemic strains with high prevalence in hospitals. In this single centre matched control study we compared a new commercially available DNA microarray (IdentiBAC) with standard spa-typing for S. aureus genotyping. Included in the study was a subgroup of 46 MRSA and matched 46 MSSA nasal isolates of the Saarland University Medical Center collected during a state-wide admission prevalence screening. Microarray (MA) and also spa-typing could easily differentiate the genetically diverse MSSA group. However, due to the predominance of CC5/t003 in the MRSA group a sufficient subtyping required analysis of more complex genetic profiles as was shown here by the MA comprising a total number of 334 different hybridization probes. The genetic repertoire of the MRSA group was characterized by more virulence genes as compared to the MSSA group. The standard evaluation of MA results by the original software into CCs, agr-, SCCmec- and capsule-types was substituted in the present study by implementation of multivariate subtyping of closely related CC5 isolates using three different bioinformatic methods (splits graph, cluster dendrogram, and principal component analysis). Each method used was applicable for standardized and highly discriminative subtyping with high concordance. We propose that the identified S. aureus subtypes with characteristic virulence gene profiles are presumably associated also with virulence and pathogenicity in vivo; however, this remains to be analyzed in future studies. MA was superior to spa-typing for epidemiologic and presumably also provide functional respectively virulence associated characterization of S. aureus isolates. This is of specific importance for the hospital setting. In future, MA could become a new standard test for S. aureus typing in combination with multivariate bioinformatic analysis.

PubMed

Review of a major epidemic of methicillin resistant Staphylococcus aureus: The costs of screening and consequences of outbreak management.

Aug 2012

van der Zee A, Hendriks WD, Roorda L, Ossewaarde JM, Buitenwerf J.

Source

Molecular Diagnostics Unit, Maasstad Hospital, Rotterdam, The Netherlands.

Abstract 

BACKGROUND:

A major outbreak of methicillin-resistant Staphylococcus aureus (MRSA) occurred in locations C and Z of our hospital and lasted for several years. It affected 1,230 patients and 153 personnel.

METHODS:

Outbreak management was installed according to the Dutch "search and destroy" policy. A rapid, high-throughput method for molecular screening of potential MRSA carriers was implemented. Outbreak isolates were retrospectively genotyped by pulsed field gel electrophoresis. Costs of molecular screening were compared with screening by culture.

RESULTS:

Genotyping results revealed 4 distinct epidemic MRSA clones. Three were present in hospital C. Because of a merger of hospitals, these clones spread to hospital Z. Another clone of MRSA affected other health care-related institutions in the region. Because of the implementation of strict containment measures of the "search and destroy" policy, the annual number of tests decreased from 100,000 to 18,000. The disposables and reagents used in polymerase chain reaction technology are more expensive than those of conventional methods. However, the clinical and economic benefits of fast results in regard to expenses of the hospital clearly outweigh the higher costs of screening.

CONCLUSION:

The implementation of a rapid, high-throughput molecular screening system greatly contributed to the effectiveness of strict containment measures of the "search and destroy" policy. The major epidemic clones of MRSA in the outbreak were eradicated by this strategy.

PubMed

Methicillin resistant Staphylococcus aureus: carriage rates and characterization of students in a Texas university.

Methicillin resistant Staphylococcus aureus: carriage rates

and characterization of students in a Texas university.

Clin Lab Sci. 2009 Summer

Rohde RE, Denham R, Brannon A.

Clinical Laboratory Science, Texas State University-San Marcos, San Marcos, TX 78666-4616, USA. rrohde@txstate.edu

OBJECTIVE: To evaluate the carriage rates of Staphylococcus aureus and methicillin resistant Staphylococcus aureus (MRSA) in a university student population and describe risk factors associated with the carriage of each. DESIGN: Cross-sectional study (N = 203). Institutional Review Board approval was obtained from Texas State University-San Marcos.

SETTING: Texas State University-San Marcos, San Marcos, TX.

PARTICIPANTS: Two-hundred and three university student samples were collected from December 2007 to July 2008.

INTERVENTIONS: None indicated.

MAIN OUTCOME MEASURES: The sample set was screened for S. aureus and MRSA identification by standard microbiological techniques and confirmed by use of a Vitek 2 per manufacturer recommendation. Antibiotic susceptibility testing was conducted on each MRSA isolate by Vitek 2. A questionnaire was conducted with each student to acquire demographic and risk factor information. Demographic data is shown by raw numbers, percentages, mean, and median where applicable. The compiled data was screened and analyzed by chi square (p values) and odds ratio (OR) with confidence interval (CI) to determine significance.

RESULTS: Of the 203 participants who were screened, 60 (29.6%) carried S. aureus. Univariate analysis found that only hospitalization in the past 12 months was significantly associated with the risk of being a S. aureus carrier (OR=3.0, 95% CI 1.28-7.03). Of the 60 participants that carried S. aureus, 15 were identified as MRSA. This relates to a 7.4% MRSA carriage rate among generally healthy university students. Univariate analysis found that hospitalization in the past 12 months (OR = 4.2, 95% CI 1.29-13.36) and recent skin infection (OR = 4.4, 95% CI 1.07-18.24) were significantly associated with the risk of being a MRSA carrier. No unique antibiotic susceptibility patterns were identified with the MRSA isolates.

CONCLUSIONS: The carriage rate of S. aureus is consistent with similar studies. MRSA carriage in this university study appears high as compared to the general population. Although this study did not confirm a variety of risk factors for carriage of MRSA previously identified by others, university healthcare personnel should be aware of the changing epidemiology of MRSA and preventive measures needed to avoid outbreaks.

PMID: 19827412 [PubMed - in process]