Transmission of methicillin-resistant Staphylococcus aureus in an acute care hospital in Japan

MOLECULAR EPIDEMIOLOGY OF THE TRANSMISSION OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS IN KYIV ACUTE CARE HOSPITALS, UKRAINE

OBJECTIVE

The aim: To evaluate the potential of transmission of methicillin-resistance Staphylococcus aureus (MRSA) in Ukrainian acute care hospitals.

PATIENTS AND METHODS

Materials and methods: We performed a multicenter cross-sectional study. Definitions of HAI were used from the CDC/ NHSN. The susceptibility to antibiotics was determined by disk diffusion method according to the EUCAST. The cefoxitin-resistant isolates S.aureus were analyzed for the presence of the mecA gene and femA endogenous control gene using PCR. The virulence factor encoding genes (lukS-PV and lukF-PV) were detected by PCR.

RESULTS

Results: Of 2,421 patients with HAIs caused S.aureus included in the study, 28.7% patients had MRSA. Prevalence of nasal carriage rate of MRSA among healthcare workers (HCWs) was 33.3%. MRSA contamination of hands and uniforms/gowns of HCW were 32.2% and 29.7%, respectively. MRSA contamination in the inanimate environment surfaces in near- and extended patients areas were 26.9%. The predominant MRSA contamination in hospital environment surfaces were: room inner door knob (32.8%), bed rails (28.9%), room light switch (28.9%), chair (27.9%), bedside table handle (20.6%), bedside table (20.5%), and tray table (13.7%). The PVL gene was present in 38.7% of MRSA strains, isolated from patients with HAIs and in 55.7% of MRSA, isolated from environment surfaces in patient area. In addition, the PVL genes were detected in over 56.3% of MRSA isolated from HCWs carrier.

CONCLUSION

Conclusions: The majority of MRSA is acquired during hospitalization. Environmental surfaces may serve as potential reservoirs for nosocomial MRSA and facilitate transmissions via contact.

Dynamic change of blood profile in rat models with acute skin injury artificially infected with methicillin-resistant Staphylococcus aureus

Background and Aim:

A wound is a common problem for humans and animals. The wound becomes more severe if it is infected by bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). The wound healing mechanism involves various factors, either in the local tissue or the bloodstream. However, the presentation of infected wound healing regarding its impacts on the dynamic change of blood profile is not clearly understood. This study aimed to explore the impacts of wound creation on the blood profile in rat models with and without being artificially infected by MRSA.

Materials and Methods:

Thirty male Sprague-Dawley rats (6 months old; weight, 300 g) were used as the model. They were divided into three groups: Without wound creation (C), wounded without infection (CW), and wounded and artificially infected by MRSA (CWI). Groups CW and CWI were shaved and induced with 4 mm two-round full-thickness biopsy on the back. Furthermore, group CWI was artificially infected by 105 colony-forming units of MRSA. The blood samples were collected through the tail vein from days 1 to 5. The blood parameters included blood profile, total plasma protein, C-reactive protein, CD4⁺, CD8⁺, CD4⁺/CD8⁺, and COX-2. The data were analyzed using the Statistical Package for the Social Sciences, version 16 (SPSS, IBM, Armonk, NY, USA).

Results:

The result showed that the presentation of a wound with and without MRSA infection significantly changed the total erythrocytes, leukocytes, neutrophils, lymphocytes, total plasma protein, C-reactive protein, and the subset of circulatory CD4⁺, CD8⁺, and COX-2 (p≤0.05). In addition, the wound infected with MRSA impacts the mean corpuscular volume (p≤0.05).

Conclusion:

Moreover, the presentation of the wound with and without MRSA infection induces dynamic changes on various blood profile parameters.

Intranasal octenidine for methicillin-resistant Staphylococcus aureus (MRSA) carriers and universal octenidine bathing reduced MRSA acquisition in an acute-care general ward

In this quasi-experimental before-and-after study in a methicillin-resistant staphylococcus aureus (MRSA) high-prevalence acute-care dermatology ward from August 2016 to November 2018, patients admitted during intervention period who received additional topical intranasal octenidine were 63% less likely to acquire MRSA than those receiving universal daily octenidine bathing alone during baseline period (aOR, 0.37; 95% CI, 0.14-0.98).

Risk factors associated with methicillin-resistant Staphylococcus aureus isolation from serially collected sputum samples of patients hospitalized with pneumonia

INTRODUCTION

Risk factors associated with the new detection of methicillin-resistant Staphylococcus aureus (MRSA) during hospitalization remain unclear. This study aimed to identify risk factors associated with MRSA isolation from the sputum of patients admitted with pneumonia, during their hospitalization.

METHODS

Patients were prospectively enrolled from 2003 to 2012. Sputum samples were collected for bacterial cultures on days 1, 4, 7, 11, and 14 of hospitalization and thereafter. Cases of MRSA first isolated from sputum obtained before day 4 were defined as "carriage on admission." Cases of MRSA first isolated on day 4 and thereafter, were defined as "new detection after admission." Statistical analysis was used to investigate the risk factors associated with MRSA isolation.

RESULTS

MRSA was isolated from 167 of 1,008 patients (carriage: 47; new detection: 120). Multivariate analysis revealed that the risk factors for MRSA carriage were activities of daily living (ADL) disability prior to admission (odds ratio [OR], 2.92; 95% confidence interval [CI], 1.37-6.22) and hospitalization within the previous 90 days (OR, 3.75; 95% CI, 1.90-7.41). ADL disability prior to admission (risk ratio [RR], 1.82; 95% CI, 1.17-2.84) and a high pneumonia severity index score upon admission (RR, 2.20; 95% CI, 1.37-3.65) were risk factors for new detection of MRSA.

CONCLUSIONS

Several risk factors were found to be associated with MRSA carriage and/or its new detection, based on the sputum samples from patients admitted with pneumonia. These factors may be indicators for selective surveillance and the early implementation of infection control measures.

Prevalence and characteristics of methicillin-resistant Staphylococcus aureus colonization among healthcare professionals in a university hospital in Japan

BACKGROUND

Asymptomatic carriers of methicillin-resistant Staphylococcus aureus (MRSA) are important sources of nosocomial transmission. MRSA may be transmitted from hospitalized patients to healthcare professionals and vice versa.

METHODS

The prevalence of MRSA colonization among forty-five healthcare professionals in a Japanese hospital was determined by performing surveillance cultures to identify unrecognized carriers of MRSA. All MRSA isolates were evaluated using multilocus sequence typing (MLST) to identify the transmission routes.

RESULTS

The proportion of MRSA colonization was significantly higher in healthcare professionals (11.1%) than in community residents (0.72%; P < 0.0001) or admission case (2.5%; P = 0.018). MLST analysis revealed that both the ST8 and ST764 strains were identified in residents, patients, and healthcare professionals. MRSA colonization was more frequently observed among physicians (4/13; 31%) than nurses (1/32; 3%) (P = 0.020).

CONCLUSION

Multilocus sequence typing results suggest that ST8 and ST764 are involved in the occurrence of nosocomial MRSA infections. These findings emphasize the necessity for the effective education of physicians to prevent MRSA transmissions.