From the Guidelines
Staphylococcus lugdunensis is generally susceptible to cephalosporins, and treatment with cloxacillin is recommended, as it is always methicillin susceptible. According to the 2015 ESC guidelines for the management of infective endocarditis 1, S. lugdunensis can be treated with cloxacillin, which is a type of cephalosporin. This is because S. lugdunensis is always methicillin susceptible, unlike many other coagulase-negative staphylococci.
Some key points to consider when treating S. lugdunensis infections include:
- The use of cephalosporins, such as cloxacillin, as a first-line treatment option
- The importance of antibiotic susceptibility testing to confirm sensitivity and guide optimal therapy
- The need for careful monitoring for the development of periannular extension or extracardiac spread of infection, as S. lugdunensis tends to cause a more virulent form of IE 1
- The use of specialized assays, such as pyrrolidonyl aminopeptidase hydrolysis testing, to differentiate S. lugdunensis from other coagulase-negative staphylococci 1
It's worth noting that while methicillin-resistant strains of S. lugdunensis do exist, they are less common than methicillin-resistant S. aureus (MRSA) 1. However, the susceptibility of S. lugdunensis to cephalosporins is due to its cell wall composition and the mechanism of action of cephalosporins, which inhibit bacterial cell wall synthesis.
In terms of treatment duration, it typically ranges from 7-14 days depending on the infection site and severity. For empiric treatment of S. lugdunensis infections, cefazolin 1-2g IV every 8 hours is often appropriate for serious infections, while oral cephalexin 500mg four times daily can be used for less severe cases. However, cloxacillin is the recommended treatment option, as stated in the 2015 ESC guidelines 1.
From the Research
Susceptibility of Staphylococcus lugdunensis to Cephalosporins
- The susceptibility of Staphylococcus lugdunensis to cephalosporins is not explicitly stated in the provided studies, but we can infer its susceptibility to certain antibiotics based on the available data.
- A study from 2019 2 found that S. lugdunensis remains susceptible to most antibiotics, with 74.6% of isolates susceptible to penicillin G.
- Another study from 2009 3 found that all S. lugdunensis isolates lacked the mecA gene and were susceptible to oxacillin by broth microdilution, E-test, and cefoxitin disk diffusion test.
- A 2022 review 4 noted that European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Clinical and Laboratory Standards Institute (CLSI) differ in their methodology and breakpoints for the detection of penicillin and oxacillin resistance in S. lugdunensis.
- A 2022 study 5 found that 1.8% of S. lugdunensis isolates were resistant to oxacillin, with the mecA gene detected on SCCmec-V.
Cephalosporin Resistance
- While there is no direct information on cephalosporin resistance, a 2025 study 6 found that 16% of S. lugdunensis isolates were resistant to oxacillin.
- The same study found that 84.1% of isolates were susceptible to oxacillin, which may indicate some level of susceptibility to cephalosporins, although this is not explicitly stated.
Antibiotic Susceptibility
- The studies suggest that S. lugdunensis is generally susceptible to most antibiotics, including penicillin G, oxacillin, and vancomycin 2, 3, 6.
- However, there is emerging resistance to certain antibiotics, such as oxacillin, in some geographical areas 4, 6.
- A 2022 study 5 found that 21.4% of S. lugdunensis isolates were resistant to fosfomycin, and 5% of isolates had a multidrug-resistant phenotype.