From the Guidelines
Staphylococcus epidermidis infections should be treated with a combination of antibiotics, such as teicoplanin and meropenem, and in some cases, removal of infected medical devices, as evidenced by a recent study published in 2020 1.
Overview of Staphylococcus epidermidis
Staphylococcus epidermidis is a gram-positive bacterium that naturally colonizes human skin and mucous membranes as part of the normal microbiota. It is a coagulase-negative staphylococcus that typically appears as white, round colonies when cultured. While generally considered non-pathogenic, S. epidermidis can cause opportunistic infections, particularly in individuals with compromised immune systems or when introduced into normally sterile body sites through medical devices like catheters, prosthetic joints, or heart valves.
Treatment of Staphylococcus epidermidis Infections
These infections are concerning because S. epidermidis often forms biofilms, protective layers that shield bacteria from antibiotics and the immune system. Treatment typically involves antibiotics such as vancomycin, linezolid, or daptomycin, especially for methicillin-resistant strains. In many cases, complete removal of infected medical devices is necessary for successful treatment. A study published in 2020 1 demonstrated the effectiveness of treating S. epidermidis infections with a combination of antibiotics, such as teicoplanin and meropenem, and in some cases, removal of infected medical devices.
Antibiotic Resistance and Treatment Options
The bacterium's increasing antibiotic resistance, particularly to methicillin (MRSE), presents a growing clinical challenge in healthcare settings, especially in hospital-acquired infections. Another study published in 2009 1 discussed the use of antibiotic lock therapy as a treatment option for catheter-related bloodstream infections caused by S. epidermidis, with a success rate of 75%-84%. However, the most recent and highest-quality study 1 should be prioritized when making treatment decisions.
Key Considerations for Treatment
When treating S. epidermidis infections, it is essential to consider the following key points:
- The use of combination antibiotic therapy, such as teicoplanin and meropenem, as evidenced by the 2020 study 1
- The potential need for removal of infected medical devices
- The increasing antibiotic resistance of S. epidermidis, particularly to methicillin (MRSE)
- The importance of prioritizing the most recent and highest-quality study when making treatment decisions.
From the Research
Characteristics of Staphylococcus epidermidis
- Staphylococcus epidermidis is often regarded as a culture contaminant, but its importance as a pathogen has been recognized in recent years 2
- It is a common cause of infections involving indwelling foreign devices, surgical wound infections, and bacteremia in immunocompromised patients 2
- Staph. epidermidis isolates from nosocomial infections frequently are resistant to methicillin 2
Treatment of Staphylococcus epidermidis Infections
- Penicillin G, semisynthetic penicillinase-resistant penicillins, and cephalosporins are effective for the treatment of methicillin-sensitive Staph. epidermidis infections 2
- Vancomycin is the drug of choice for infections caused by methicillin-resistant organisms 2, 3
- Vancomycin, combined with rifampin or gentamicin, or both, is recommended for therapy of serious infections caused by methicillin-resistant strains 2
- Rifampicin is able to penetrate the biofilm, but to reduce the risk of development of rifampicin resistance it should be used in combination with an additional antibiotic 4
Antibiotic Susceptibility
- Virtually all Staph. epidermidis isolates are susceptible in vitro to vancomycin and rifampin 2
- Ninety-three (69%) of the 134 isolates were susceptible to doxycycline, 94/134 (70%) to rifampicin, 56/134 (42%) to clindamycin, 25/134 (19%) to ciprofloxacin, 81/134 (60%) to fusidic acid, and 100% to linezolid 4
- All isolates were susceptible to tigecycline and linezolid, and 97% were susceptible to daptomycin 5
- The mecA gene was detected in 85% of the isolates 5
Resistance to Antibiotics
- Cross-resistance between methicillin and cephalosporins occurs in vitro 2
- Thirty-nine per cent of the isolates were resistant to rifampicin, associated with one or two single-nucleotide polymorphisms (SNPs) in rpoB 5
- Ninety-one per cent of the isolates were multiresistant (i.e. resistant to members of more than three classes of antibiotics) 5