Blurred Molecular Epidemiological Lines Between the Two Dominant Methicillin-Resistant Staphylococcus aureus Clones

Abstract

Background Methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening infections in both community and hospital settings and is a leading cause of health care–associated infections (HAIs). We sought to describe the molecular epidemiological landscape of patients with MRSA bloodstream infections (BSIs) at an urban medical center by evaluating the clinical characteristics associated with the two dominant endemic clones. Methods Comprehensive clinical data from the electronic health records of 227 hospitalized patients ≥18 years old with MRSA BSI over a 33-month period in New York City were collected. The descriptive epidemiology and mortality associated with the two dominant clones were compared using logistic regression. Results Molecular analysis revealed that 91% of all single-patient MRSA BSIs were due to two equally represented genotypes, clonal complex (CC) 5 (n = 117) and CC8 (n = 110). MRSA BSIs were associated with a 90-day mortality rate of 27%. CC8 caused disease more frequently in younger age groups (56 ± 17 vs 67 ± 17 years old; P < .001) and in those of nonwhite race (odds ratio [OR], 3.45; 95% confidence interval [CI], 1.51–7.87; P = .003), with few other major distinguishing features. Morbidity and mortality also did not differ significantly between the two clones. CC8 caused BSIs more frequently in the setting of peripheral intravenous catheters (OR, 5.96; 95% CI, 1.51–23.50; P = .01). Conclusions The clinical features distinguishing dominant MRSA clones continue to converge. The association of CC8 with peripheral intravenous catheter infections underscores the importance of classical community clones causing hospital-onset infections. Ongoing monitoring and analysis of the dynamic epidemiology of this endemic pathogen are crucial to inform management and prevent disease.

Staphylococcus aureus Bacteremia in Patients Infected With COVID-19: A Case Series

“…These rates are much higher than reported mortality rates for patients hospitalized for COVID-19, with rates of up to 25% in patients who were mechanically ventilated [ 4 , 15 , 16 ]. Reported mortality rates for patients with S. aureus bacteremia are up to 30% [ 17–19 ]. As the median days from positive blood culture to death was <8, S. aureus bacteremia was likely to have contributed to the deaths.…”

Everybody Nose: Molecular and Clinical Characteristics of Nasal Colonization During Active Methicillin-Resistant Staphylococcus Aureus Bloodstream Infection

“…Skin and soft tissue and peripheral intravenous catheter (PIV) infections tended to correlate more frequently to the CC8 MRSA. While CC8 is associated with community skin derived infections [26], we have previously observed that CC8 was also associated with PIV infections [13] highlighting the importance of community clones causing hospital-onset infections.…”

“…The CC 5 has historically encompassed hospital-associated genotypes, and the CC8 the community genotypes. As our work [13] and others [14] [15] have found these differences and their correlations are merging, we tested the associations between infection with dominant MRSA genotypes and the salient clinical features for the study population.…”

PathoSPOT genomic epidemiology reveals under-the-radar nosocomial outbreaks

“…Variables were analyzed initially in a univariate logistic regression model. Variables p ≤0.2 were then placed into a stepwise multivariate logistic regression model [17]. An additional in-depth chart review was performed for subjects identified as being involved in transmission events.…”