Blurred molecular epidemiological lines between the two dominant methicillin-resistant Staphylococcus aureus clones

Abstract

25Background 26 Methicillin-resistant Staphylococcus aureus (MRSA) causes life-threatening infections in 27 both community and hospital settings and is a leading cause of healthcare-associated 28 infections (HAIs). We sought to describe the molecular epidemiological landscape of 29 patients with MRSA bloodstream infections (BSIs) at an urban medical center by 30 evaluating the clinical characteristics associated with the two dominant endemic clones. 31 Methods 32Comprehensive clinical data extraction from the electronic health records of 227 33 hospitalized patients ≥18 years old with MRSA BSI over a 33-month period in New York 34 City were collected. The descriptive epidemiology and mortality associated with the two 35 dominant clones was compared using logistic regression. 36 Results 37Molecular analysis revealed that 91% of all single-patient MRSA BSIs were due to two 38 equally represented genotypes, clonal complex (CC) 5 (N=117) and CC8 (N=110). 39MRSA BSIs were associated with a 90-day mortality of 27%. CC8 caused disease more 40 3 frequently in younger age groups (56 ± 17 vs 67 ± 17 years old; p<0.001) and in non- 41White race (OR=3.45 95% CI [1.51-7.87]; p=0.003), with few other major distinguishing 42 features. Morbidity and mortality also did not differ significantly between the two clones. 43CC8 caused BSIs more frequently in the setting of peripheral intravenous catheters 44 (OR=5.96; 95% CI [1.51-23.50]; p=0.01). 45 Conclusion 46 The clinical features distinguishing dominant MRSA clones continue to converge. The 47 association of CC8 with peripheral intravenous catheter infections underscores the 48 importance of classical community clones causing hospital-onset infections. Ongoing 49 monitoring and analysis of the dynamic epidemiology of this endemic pathogen is 50 crucial to inform management to prevent disease. 51 Introduction 52 Healthcare-associated infections (HAIs) pose a potentially fatal threat to patients 53 worldwide 1 and Staphylococcus aureus is one of the most common causes of HAIs in 54 the United States. 2,3 Methicillin-resistant S. aureus (MRSA) bloodstream infections 55 (BSIs) are linked with mortality up to 30% and are associated with longer hospital stays 56 and increased healthcare costs. 4,5 MRSA has long been present in healthcare settings 57 but is now well established in the community. 6 The two dominant MRSA clones in the 58 United States are clonal complex (CC) 5 and CC8. 3 Historically, CC5 has been 59 associated with older individuals with hospital or long-term care facility contact. 6 In 60contrast, CC8, predominantly the USA300 pulsotype, was first reported in the US in 61 healthy children in 1990s and raised concern for its capacity to cause severe disease in 62 majority of CC8 isolates were ST8 (N=108; 98%) with 2 (2%) additional non-ST8 clones. 132The majority (N=64; 58%) of ST8 were spa type t008, along with 20 (18%) non-t008 spa 133 types which also clustered with USA300. Additionally, CC8 included 24 (22%) spa type 134 t064, including three (3%) non-t064 spa ty...

Impact of Bicarbonate on PBP2a Production, Maturation, and Functionality in Methicillin-Resistant Staphylococcus aureus

“…The other four strains (PB 043-043, C24, PB 027-133, and PB 017-037) were selected from a larger screen of NaHCO 3 -responsive MRSA ( 12 ) based on their oxacillin and cefazolin MICs in the presence/absence of NaHCO 3 and their clonal complex (CC) types. The CC types of 7/8 isolates represent genotypes in current widespread clinical circulation (i.e., CC types 5 and 8) (see Table S1 in the supplemental material) ( 42 ). MRSA 11/11, MW2, PB 043-043, C24, BMC1001, PB 027-133, and PB 017-037 are all β-lactamase positive; COL is naturally β-lactamase negative.…”

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 (Dupper et al 2019) . An additional in-depth chart review was performed for subjects identified as being involved in transmission events.…”