Seasonal Patterns in Incidence and Antimicrobial Resistance of Common Bacterial Pathogens in Nursing Home Patients and Their Rooms

Community methicillin-resistant Staphylococcus aureus outbreaks in areas of low prevalence

BACKGROUND

Community-acquired (CA), community-onset methicillin-resistant Staphylococcus aureus (CO-MRSA) infection presents a significant public health challenge, even where MRSA rates are historically lower. Despite successes in reducing hospital-onset MRSA, CO-MRSA rates are increasing globally, with a need to understand this trend, and the potential risk factors for re-emergence.

OBJECTIVES

This review aims to explore the characteristics of outbreaks of community-acquired community-onset methicillin-resistant Staphylococcus aureus in low-prevalence areas, to understand the factors involved in its rise, and to translate this knowledge into public health policy and further research needs.

SOURCES

PubMed, EMBASE, and Google Scholar were searched using combinations of the terms 'transmission', 'acquisition', 'community-acquired', 'MRSA', 'CA-MRSA', 'low prevalence', 'genomic', 'outbreak', 'colonisation', and 'carriage'. Wherever evidence was limited, additional articles were sought specifically, via PubMed searches. Papers where materials were not available in English were excluded.

CONTENT

Challenges in defining low-prevalence areas and the significance of exposure to various risk factors for community acquisition, such as healthcare settings, travel, livestock, and environmental factors, are discussed. The importance of genomic surveillance in identifying outbreak strains and understanding the transmission dynamics is highlighted, along with the need for robust public health policies and control measures.

IMPLICATIONS

The findings emphasise the complexity of CO-MRSA transmission and the necessity of a multifaceted approach in low-prevalence areas. This includes integrated and systematic surveillance of hospital-onset-, CO-, and livestock-associated MRSA, as has been effective in some Northern European countries. The evolution of CO-MRSA underscores the need for global collaboration, routine genomic surveillance, and comprehensive antimicrobial stewardship to mitigate the rise of CO-MRSA and address the broader challenge of antimicrobial resistance. These efforts are crucial for maintaining low MRSA prevalence and managing the increasing burden of CO-MRSA in both low and higher prevalence regions.

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.

Phenotypic and Genotypic Characterization of Methicillin Resistance in Staphylococci Isolated from an Egyptian University Hospital

Methicillin-resistant in Staphylococci is a serious public health issue. It is mostly encoded by the mecA gene. The mecC gene is a new mecA analog responsible for resistance to methicillin in some Staphylococcal clinical isolates. This mecC gene is still underestimated in Egypt. The aim of the current study was to detect mecA and mecC genes in clinical Staphylococci isolates from a tertiary care university hospital in Egypt compared to the different phenotypic methods. A total of 118 Staphylococcus aureus (S. aureus) and 43 coagulase-negative Staphylococci (CoNS) were identified from various hospital-acquired infections. Methicillin resistance was identified genotypically using the PCR technique and phenotypically using the cefoxitin disc diffusion test, oxacillin broth microdilution and the VITEK2 system in all Staphylococcal isolates. The mecA gene was detected in 82.2% of S. aureus and 95.3% of CoNS isolates, while all of the isolates tested negative for the mecC gene. Interestingly, 30.2% of CoNS isolates showed the unique character of inducible oxacillin resistance, being mecA-positive but oxacillin-susceptible (OS-CoNS). The dual use of genotypic and phenotypic methods is highly recommended to avoid missing any genetically divergent strains.

Vancomycin-resistant Enterococcus faecium: admission prevalence, sequence types and risk factors-a cross-sectional study in seven German university hospitals from 2014 to 2018

OBJECTIVES

Assessment of vancomycin-resistant Enterococcus faecium (VREfm) prevalence upon hospital admission and analysis of risk factors for colonization.

METHODS

From 2014 to 2018, patients were recruited within 72 hours of admission to seven participating German university hospitals, screened for VREfm and questioned for potential risk factors (prior multidrug-resistant organism detection, current/prior antibiotic consumption, prior hospital, rehabilitation or long-term care facility stay, international travel, animal contact and proton pump inhibitor [PPI]/antacid therapy). Genotype analysis was done using cgMLST typing. Multivariable analysis was performed.

RESULTS

In 5 years, 265 of 17,349 included patients were colonized with VREfm (a prevalence of 1.5%). Risk factors for VREfm colonization were age (adjusted OR [aOR], 1.02; 95% CI, 1.01-1.03), previous (aOR, 2.71; 95% CI, 1.87-3.92) or current (aOR, 2.91; 95% CI, 2.60-3.24) antibiotic treatment, prior multidrug-resistant organism detection (aOR, 2.83; 95% CI, 2.21-3.63), prior stay in a long-term care facility (aOR, 2.19; 95% CI, 1.62-2.97), prior stay in a hospital (aOR, 2.91; 95% CI, 2.05-4.13) and prior consumption of PPI/antacids (aOR, 1.29; 95% CI, 1.18-1.41). Overall, the VREfm admission prevalence increased by 33% each year and 2% each year of life. 250 of 265 isolates were genotyped and 141 (53.2%) of the VREfm were the emerging ST117. Multivariable analysis showed that ST117 and non-ST117 VREfm colonized patients differed with respect to admission year and prior multidrug-resistant organism detection.

DISCUSSION

Age, healthcare contacts and antibiotic and PPI/antacid consumption increase the individual risk of VREfm colonization. The VREfm admission prevalence increase in Germany is mainly driven by the emergence of ST117.