Epidemiology and Prognosis of Coagulase-Negative Staphylococcal Endocarditis: Impact of Vancomycin Minimum Inhibitory Concentration

Abstract

This study describes coagulase-negative staphylococcal (CoNS) infective endocarditis (IE) epidemiology at our institution, the antibiotic susceptibility profile, and the influence of vancomycin minimum inhibitory concentration (MIC) on patient outcomes. One hundred and three adults with definite IE admitted to an 850-bed tertiary care hospital in Barcelona from 1995-2008 were prospectively included in the cohort. We observed that CoNS IE was an important cause of community-acquired and healthcare-associated IE; one-third of patients involved native valves. Staphylococcus epidermidis was the most frequent species, methicillin-resistant in 52% of patients. CoNS frozen isolates were available in 88 patients. Vancomycin MICs of 2.0 μg/mL were common; almost all cases were found among S. epidermidis isolates and did not increase over time. Eighty-five patients were treated either with cloxacillin or vancomycin: 38 patients (Group 1) were treated with cloxacillin, and 47 received vancomycin; of these 47, 27 had CoNS isolates with a vancomycin MIC <2.0 μg/mL (Group 2), 20 had isolates with a vancomycin MIC ≥2.0 μg/mL (Group 3). One-year mortality was 21%, 48%, and 65% in Groups 1, 2, and 3, respectively (P=0.003). After adjusting for confounders and taking Group 2 as a reference, methicillin-susceptibility was associated with lower 1-year mortality (OR 0.12, 95% CI 0.02-0.55), and vancomycin MIC ≥2.0 μg/mL showed a trend to higher 1-year mortality (OR 3.7, 95% CI 0.9-15.2; P=0.069). Other independent variables associated with 1-year mortality were heart failure (OR 6.2, 95% CI 1.5-25.2) and pacemaker lead IE (OR 0.1, 95%CI 0.02-0.51). In conclusion, methicillin-resistant S.epidermidis was the leading cause of CoNS IE, and patients receiving vancomycin had higher mortality rates than those receiving cloxacillin; mortality was higher among patients having isolates with vancomycin MICs ≥2.0 μg/mL.

Clinical and prognostic differences between methicillin-resistant and methicillin-susceptible Staphylococcus aureus infective endocarditis

“…The importance of vancomycin susceptibility in methicillin-resistant and even methicillin-susceptible strains is controversial. After initial studies described worse outcomes for methicillin-resistant strains with high vancomycin MIC values [9,30], various metaanalyses on the relevance of MIC in SA infections have associated values ≥2 μg/mL with higher mortality (OR 1.72; 95% CI: 1.34-2.21) and values ≥1.5 μg/mL with [31] and even in IE [32] and bacteremia due to MSSA with MIC ≥1.5 μg/ mL, which was associated with a higher risk of complicated bacteremia [33,34]. In contrast, a longitudinal, prospective, multicenter study of MRSA endocarditis found no association of vancomycin MIC ≥1.5 μg/mL with higher mortality, although it was related to a greater persistence of bacteremia and a higher frequency of sepsis/septic shock, peripheral embolism, and arthritis/osteomyelitis [35].…”

Coagulase-negative staphylococci (CoNS) meningitis: a narrative review of the literature from 2000 to 2020

“…S. epidermidis has different virulence factors such as cysteine protease, serine protease, lipase, metalloprotease with elastase activity, resistance to antibiotics, ability to produce delta toxin and ability to adhere to and form biofilm on the surface of foreign bodies such as implanted devices [ 69 , 70 ]. The ability to form biofilm on the surface of foreign bodies leads to the emergence of antibiotic-resistant S. epidermidis isolates, and the infections induced by these organisms have become increasingly difficult to eradicate.…”

İnfektif Endokarditli Çocuklarda Klinik Özellikler, Tedavi Yaklaşımları ve Komplikasyonlar: Türkiye’den Tek Merkez Deneyimi

“…In recent years, an increase in the frequency of bacteremia and endocarditis caused by CNSA has been reported, including native valve endocarditis (22). Maria et al (23) reported that the prevalence of CNSA-related IE was 16% and the frequency of native valve endocarditis was 35% in their adult studies, which included 13 years of data. In our study, CNSA was the most frequent IE agent with five cases (45.5%), where three patients had native valves and two had condiut valves.…”