Future Methicillin-resistant Staphylococcus Aureus Research Articles

The Prevalence, Epidemiological, and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus (MRSA) in Macau (2017-2022).

Macau, recognized as a global tourism hub and the world's most densely populated region, provides a unique environment conducive to methicillin-resistant Staphylococcus aureus (MRSA) transmission in healthcare and community settings, posing a significant public health concern both locally and globally. The epidemiology and molecular characteristics of MRSA in the distinct city of Macau remain largely unelucidated. This five-year longitudinal study (2017-2022) examined the local prevalence and molecular typing of MRSA in Macau, with future MRSA type distribution predicted through ARIMA modeling. We subsequently analyzed the epidemiological characteristics of MRSA, including specimen source, clinical department, collection year, season, patient age, sex, and the annual number of tourists. Comprehensive antibiotic resistance profiles of the strains were also assessed. Of 504 clinically isolated S. aureus strains, 183 (36.3%) were identified as MRSA by the cefoxitin disk diffusion method and validated through multi-locus sequence typing (MLST). The MRSA detection rate showed an upward trend, increasing from 30.1% in 2017 to 45.7% in 2022. SCCmec type IV was predominant (28.9%), followed by types II (25.4%), III (22.1%), and V (22.1%). The primary sources of MRSA isolates were sputum (39.2%) and secretions (25.6%). Older age emerged as a risk factor for MRSA infection, whereas no significant associations were found with seasonal variations, gender, or the annual number of tourists. Despite displaying universal resistance to cefoxitin, oxacillin, and benzylpenicillin, MRSA isolates in Macau remained fully sensitive to vancomycin, tigecycline, quinupristin, nitrofurantoin, and linezolid. Continuous surveillance and analysis of MRSA distribution in Macau could provide invaluable insights for the effective management of MRSA prevention and control measures within healthcare settings.

The return of MRSA in a post pandemic world

Since the beginning of the Coronavirus pandemic (COVID-19 virus), society has, and continues to, excessively clean and disinfect surfaces and objects that come into contact with our hands. The COVID-19 virus has been declared a public health emergency by a myriad of health organizations world-wide. While the symptoms of COVID-19 vary, the intensive use of disinfectants in society, associated with COVID-19 pandemic, may give rise to a new pandemic in the form of Methicillin-resistant Staphylococcus aureus (MRSA). The reaction of the public’s response to COVID-19 pandemic has increased the cleanliness and disinfection of surfaces that may manifest into a new outbreak, because MRSA has the ability to adapt to a changing environment. The effects of consistent use of hand sanitizers could ultimately alter the human microbiome; which, in-turn, creates a change in the diversity of the microbial community, reducing competition and other interactions among the normally diverse microbial communities, leading to possible expansive growth of antimicrobial resistant bacteria, thus making humans more susceptible to not only MRSA, but also other infectious diseases. This article is an overview pertaining to the overuse of hand sanitizers, characteristics of MRSA, its diagnosis, clinical features, and preventive measures to avoid a future MRSA outbreak.

Evaluation of Methicillin-Resistant Staphylococcus aureus Carriage and High Livestock Production Areas in North Carolina through Active Case Finding at a Tertiary Care Hospital

Recent reports from the Netherlands document the emergence of novel multilocus sequence typing (MLST) types (e.g., ST-398) of methicillin-resistant Staphylococcus aureus (MRSA) in livestock, particularly swine. In Eastern North Carolina (NC), one of the densest pig farming areas in the United States, as many as 14% of MRSA isolates from active case finding in our medical center have no matches in a repetitive sequence-based polymerase chain reaction (rep-PCR) library. The current study was designed to determine if these non-matched MRSA (NM-MRSA) were geographically associated with exposure to pig farming in Eastern NC. While residential proximity to farm waste lagoons lacked association with NM-MRSA in a logistic regression model, a spatial cluster was identified in the county with highest pig density. Using MLST, we found a heterogeneous distribution of strain types comprising the NM-MRSA isolates from the most pig dense regions, including ST-5 and ST-398. Our study raises the warning that patients in Eastern NC harbor livestock associated MRSA strains are not easily identifiable by rep-PCR. Future MRSA studies in livestock dense areas in the U.S. should investigate further the role of pig–human interactions.

Methicillin-resistant Staphylococcus aureus spreading through medical devices used in nursing care: what can we learn from Portugal?

Background: Presently, Portugal faces the third highest level of Staphylococcus aureus in the European Union, leading to burdensome outcomes for health systems, public institutions, patients and their respective families. A significant contamination rate of portable medical devices used by nurses in direct patient care was identified in four medical wards in a large public tertiary hospital. We described the degree of contamination and investigate associated risk factors. Methods & Materials: Descriptive-correlational and cross-sectional study. The target population corresponds to all nurses who provide direct patient care in the referred settings. Medical devices were swabbed and cultured in Mannitol salt agar (MSA). The obtained isolates were subjected to the latex agglutination test in order to investigate the presence of Staph. aureus. Additional information regarding medical devices management by nurses was collected by individual questionnaire. Data were analyzed with IBM SPSS 20. Results: Between April and June 2017, 383 medical devices carried by 50 nurses in their uniform pockets were tested. The most representative devices were tourniquets (68%), adhesive rolls (56%), scissors (26%) and thermometers (20%). Colonies of Staphylococcus coagulase positive (32%) and negative (27%) were identified, ranging from 1.0 × 101 to > 1.5 × 103 CFU/mL. The highest CFU/mL values were observed in reusable tourniquets and axillary thermometers. Overall, and regarding Staphylococcus isolates, 66.6% were positively identified as Methicillin-resistant Staphylococcus aureus (MRSA). Data retrieved from questionnaires evidences that nurses reuse these devices between patients (100%); commonly share these devices with other healthcare professionals such as other nurses, physicians and assistants (92%), are unaware of clinical guidelines regarding medical devices management (82%); lack infection prevention and control training (42%); and don’t properly clean these devices during patient care (32.7%). Conclusion: Fundamental lack of recurrent training, access to specific institutional guidelines and ineffective management of these devices, including lack of cleaning/disinfection, reuse between procedures/patients and sharing them with other professionals were associated with MRSA. The implementation of pathways for medical device management, mandatory staff training and introduction of single-use medical devices in medical wards are recommended to prevent/control future MRSA outbreaks.

Bacteriostatic antimicrobial combination: antagonistic interaction between epsilon-viniferin and vancomycin against methicillin-resistant Staphylococcus aureus.

Stilbenoids have been considered as an alternative phytotherapeutic treatment against methicillin-resistant Staphylococcus aureus (MRSA) infection. The combined effect of ε-viniferin and johorenol A with the standard antibiotics, vancomycin and linezolid, was assessed against MRSA ATCC 33591 and HUKM clinical isolate. The minimum inhibitory concentration (MIC) value of the individual tested compounds and the fractional inhibitory concentration index (FICI) value of the combined agents were, respectively, determined using microbroth dilution test and microdilution checkerboard (MDC) method. Only synergistic outcome from checkerboard test will be substantiated for its rate of bacterial killing using time-kill assay. The MIC value of ε-viniferin against ATCC 33591 and johorenol A against both strains was 0.05 mg/mL whereas HUKM strain was susceptible to 0.1 mg/mL of ε-viniferin. MDC study showed that only combination between ε-viniferin and vancomycin was synergistic against ATCC 33591 (FICI 0.25) and HUKM (FICI 0.19). All the other combinations (ε-viniferin-linezolid, johorenol A-vancomycin, and johorenol A-linezolid) were either indifferent or additive against both strains. However, despite the FICI value showing synergistic effect for ε-viniferin-vancomycin, TKA analysis displayed antagonistic interaction with bacteriostatic action against both strains. As conclusion, ε-viniferin can be considered as a bacteriostatic stilbenoid as it antagonized the bactericidal activity of vancomycin. These findings therefore disputed previous report that ε-viniferin acted in synergism with vancomycin but revealed that it targets similar site in close proximity to vancomycin's action, possibly at the bacterial membrane protein. Hence, this combination has a huge potential to be further studied and developed as an alternative treatment in combating MRSA in future.

Radiocomplexation and biological characterization of the 99mTcN-trovafloxacin dithiocarbamate: a novel methicillin-resistant Staphylococcus aureus infection imaging agent

The radiolabeling of trovafloxacin dithiocarbamate (TVND) with technetium-99m using [99mTc-N]2+ core was investigated and biologically assessed as prospective infection imaging agent. The achievability of the 99mTcN-TVND complex as a future MRSA infection radiotracer was investigated in artificially methicillin-resistant Staphylococcus aureus (MRSA) infected male Sprague–Dawley rats (MSDR). Radiochemically the 99mTcN-TVND complex was characterized in terms of radiochemical purity (RCP) in saline, in vitro permanence in serum, in vitro binding with MRSA and biodistribution in living and heat killed MRSA infected MSDR. Radiochemically the complex showed stability in saline with a 97.90 ± 0.22% yield and serum at 37 °C up to 4 h. The 99mTcN-TVND complex showed saturated in vitro binding with MRSA. Normal in vivo uptake in the MRSA infected MDRS was observed with a five fold uptake in the infected muscle as compared to inflamed and normal muscles. The high RCP values, in vitro permanence in serum, better in vitro binding with MRSA, biodistribution behavior and the target to non-target (infected to inflamed muscle) ratios posed the 99mTcN-TVND complex as a promising MRSA infection radiotracer.

Personal Hygiene and Methicillin-resistantStaphylococcus aureusInfection

Methicillin-resistant Staphylococcus aureus (MRSA) infections outside the healthcare setting are an increasing concern. We conducted a case-control study to investigate an MRSA outbreak during 2002-2003 in a Missouri prison and focused on hygiene factors. Information on sociodemographic characteristics, medical history, and hygiene practices of study participants was collected by interview and medical record review. Logistic regression was used to evaluate MRSA infection in relation to hygiene factors individually and as a composite hygiene score; potential confounding factors were controlled. Selected MRSA isolates were analyzed by pulsed-field gel electrophoresis (PFGE). MRSA infection was significantly associated with a low composite hygiene score. Transmission among prison inmates appeared to be responsible for this outbreak. PFGE analysis showed that isolates were indistinguishable and associated with community-onset MRSA infections in other US prisons. Improving hygiene practices and environmental conditions may help prevent and interrupt future MRSA outbreaks in prison settings.

Predicting methicillin resistance and the effect of inadequate empiric therapy on survival in patients with Staphylococcus aureus bacteremia.

The restriction of vancomycin hydrochloride use is recommended as a measure to decrease the emergence of vancomycin resistance in gram-positive organisms; however, vancomycin also is the treatment of choice for methicillin-resistant Staphylococcus aureus (MRSA) infections. If vancomycin use is restricted to patients with documented infections due to methicillin-resistant organisms, then patients with MRSA infections may not initially receive vancomycin. This study was performed to determine factors that predict MRSA bacteremia and if ineffective empiric antibiotic therapy increased the risk of death in patients with S aureus bacteremia. We conducted a retrospective cohort study of all patients with clinically significant S aureus bacteremia (132 episodes in 128 patients) diagnosed between October 1, 1995, and January 1, 1998, at an urban acute care Veterans Affairs medical center (approximately 200 acute care beds) in Baltimore, Md. During the study period, vancomycin was a restricted antibiotic. Empiric use had to be approved by an attending physician specializing in infectious diseases. Compared with patients who had methicillin-sensitive S aureus bacteremia, patients with MRSA bacteremia were significantly older (70 vs 58 years; P<.01), more likely to have a history of MRSA (47% vs 6%; P<.01) and a nosocomial infection (76% vs 50%; P<.01), and less likely to use injection drugs (8% vs 32%; P<.01). In addition, compared with patients who had methicillin-sensitive S aureus bacteremia, patients with MRSA bacteremia were significantly less likely (45% vs 98%; P<.01) to receive effective antibiotic therapy during the first 48 hours of hospitalization. However, the risk of death due to ineffective empiric therapy was less than 1 (relative risk, 0.82; 95% confidence interval, 0.36-1.88) and did not change significantly when adjusted for age, occurrence of sepsis, or nosocomial infection. The results of this study support the safety of the restriction of vancomycin use in patients with clinically significant S aureus bacteremia. However, patients with a history of MRSA are more likely to have future MRSA infections and should receive empiric therapy using vancomycin for possible S aureus infections, particularly for nosocomial infections.