Staphylococcus aureus injection drug use-associated bloodstream infections are propagated by community outbreaks of diverse lineages

Abstract

Background The ongoing injection drug use (IDU) crisis in the United States has been complicated by an emerging epidemic of Staphylococcus aureus IDU-associated bloodstream infections (IDU-BSI). Methods We performed a case-control study comparing S. aureus IDU-BSI and non-IDU BSI cases identified in a large US Midwestern academic medical center between Jan 1, 2016 and Dec 21, 2019. We obtained the whole-genome sequences of 154 S. aureus IDU-BSI and 91 S. aureus non-IDU BSI cases, which were matched with clinical data. We performed phylogenetic and comparative genomic analyses to investigate clonal expansion of lineages and molecular features characteristic of IDU-BSI isolates. Results Here we show that patients with IDU-BSI experience longer durations of bacteremia and have lower medical therapy completion rates. In phylogenetic analyses, 45/154 and 1/91 contemporaneous IDU-BSI and non-IDU BSI staphylococcal isolates, respectively, group into multiple, unique clonal clusters, revealing that pathogen community transmission distinctively spurs IDU-BSI. Lastly, multiple S. aureus lineages deficient in canonical virulence genes are overrepresented among IDU-BSI, which may contribute to the distinguishable clinical presentation of IDU-BSI cases. Conclusions We identify clonal expansion of multiple S. aureus lineages among IDU-BSI isolates, but not non-IDU BSI isolates, in a community with limited access to needle exchange facilities. In the setting of expanding numbers of staphylococcal IDU-BSI cases consideration should be given to treating IDU-associated invasive staphylococcal infections as a communicable disease.

Infective Endocarditis in High-Income Countries

“…The phenomenon of mutating epidemiology of infective endocarditis in high-income countries is related to substantial progress in the medical and surgical fields [ 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 ]. Therefore, an increase of 25–30% of contemporary cases of IE are acquired in the health sector, either due to the progressive increase in medical care offered during hospitalization or nosocomial admission, or to the possibility of contracting the infection on an outpatient basis [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ].…”

Outcomes of Partial Oral Antibiotic Treatment for Complicated Staphylococcus aureus Bacteremia in People Who Inject Drugs

“…Methodologically, we attempted to adjust for baseline covariate imbalance by fitting models including inverse probability weights, but this cannot overcome underlying systematic unmeasured confounding between the groups. Lastly, patients in this cohort were immunocompetent, and younger than the average aged patient with non-PWID associated S. aureus infections, and many of the S. aureus strains causing infections in this cohort have been previously identified as having fewer virulence factors and supra-antigenic toxins than what is often seen in non-PWID associated S. aureus infections [16].…”

“…We completed a retrospective cohort analysis of patients admitted to Barnes Jewish Hospital (BJH) in St. Louis, Missouri, with S. aureus bloodstream infections and a history of active or recent injection drug use (IDU). Patients were identified from microbiology blood culture results that were positive for S. aureus from 1/2016 -12/2021, and all charts were reviewed for IDU history as described previously [16]. Patients were included if they had at least 1 positive blood culture for S. aureus, a history of active or recent IDU on chart review, evidence of either infective endocarditis, septic arthritis, epidural abscess, and/or vertebral osteomyelitis, as diagnosed in infectious diseases (ID) consult notes, and if they survived to hospital discharge.…”

Pathophysiology of Infective Endocarditis in High-Income Countries

“…[54,55] The phenomenon of mutating epidemiology of infective endocarditis in high-income countries is related to substantial progress in the medical and surgical fields. [56][57][58][59][60][61][62][63][64][65][66] Therefore, an increase of 25-30% of contemporary cases of IE are acquired in the health sector, either due to the progressive increase in medical care offered during hospitalization or nosocomial admission or linked to the possibility of contracting the infection on an outpatient basis [1][2][3][4][5][6][7] In this context, there has been increasing use of long-term intravenous lines and invasive procedures which constitute an ideal gateway for pathogens leading to increased rates of staphylococcal bacteremia which today represents the first precursor of infective endocarditis. [67][68][69][70] Advances in cardiological disciplines have allowed wider use of prosthetic heart valves and cardiac devices such as permanent pacemakers.…”