The bacterium Corynebacterium jeikeium is a type of Gram-positive rod-shaped organism often found on human skin. While most bacteria of this type are harmless, C. jeikeium possesses the ability to cause severe, life-threatening infections under certain circumstances. This organism is primarily recognized for its unique pattern of resistance to multiple common antibiotics. Understanding the dual nature of C. jeikeium and its resistance mechanisms is important for managing infections it causes.
The Nature of Corynebacterium Jeikeium: Commensal vs. Pathogen
Corynebacterium jeikeium is considered a member of the human skin flora, meaning it normally lives on the skin without causing disease. The bacterium is lipophilic, thriving in lipid-rich areas of the body, such as the axilla, inguinal, and rectal regions. This normal presence often leads to it being dismissed as a simple contaminant when isolated from cultures.
The organism is classified as a non-spore-forming, Gram-positive rod. The relationship between the bacteria and its host is typically commensal, where the organism benefits without causing harm. This balance shifts when the body’s natural defenses are compromised, allowing the organism to transition into an opportunistic pathogen.
This change occurs when the skin barrier is broken or the host’s immune system is weakened. Colonization is particularly common in hospitalized patients, especially those treated with broad-spectrum antibiotics. The organism can then enter the bloodstream or deep tissues, leading to serious infection.
Clinical Infections and High-Risk Patient Groups
Infection with C. jeikeium is a significant concern primarily within healthcare settings, where it causes hospital-acquired infections. The bacterium is a threat to individuals whose immune systems are suppressed, such as cancer patients undergoing chemotherapy, especially those experiencing neutropenia. These individuals lack the necessary defenses to contain the organism.
The presence of indwelling foreign materials and medical devices also significantly increases the risk of infection. This includes patients with central venous catheters, which provide a direct pathway for the bacteria to enter the bloodstream. Patients with prosthetic devices, such as artificial heart valves or joint replacements, are also vulnerable to colonization.
The infections caused by C. jeikeium are varied and severe. Common clinical manifestations include:
- Bloodstream infections (septicemia), which can quickly become life-threatening.
- Endocarditis, a serious infection of the heart valves, which carries a high mortality rate.
- Meningitis.
- Pneumonia.
- Soft tissue infections.
The Challenge of Intrinsic Antibiotic Resistance
The principal difficulty in treating C. jeikeium infections is the organism’s intrinsic resistance to many common antibiotics. This means that the organism naturally possesses mechanisms that protect it from certain drugs. For instance, a large majority of clinical isolates are resistant to beta-lactam antibiotics, which include penicillins and cephalosporins.
This broad-spectrum resistance extends to several other classes of drugs, such as macrolides and aminoglycosides, making the initial selection of an effective treatment challenging for clinicians. The resistance to these widely used drugs is often due to the presence of specific genetic elements. This extensive resistance profile earned the organism its initial designation as a highly resistant coryneform bacterium.
Because of this predictable multidrug resistance, Vancomycin is typically considered the drug of choice for treating C. jeikeium infections. Vancomycin belongs to the glycopeptide class and is one of the few drugs to which most isolates remain susceptible. The potential for this organism to acquire resistance to Vancomycin is a major concern, as it would leave few reliable treatment options. Other effective alternatives include Linezolid and Daptomycin, which are reserved for cases where Vancomycin is not suitable or has failed.
Diagnosis and Controlling Hospital Spread
The initial diagnosis of a C. jeikeium infection begins with culturing the organism from a normally sterile site, such as the blood or cerebrospinal fluid. Because the bacterium is a normal skin inhabitant, its isolation from a culture must be carefully interpreted, especially in immunocompromised patients, where it is rarely considered a simple contaminant. Advanced laboratory techniques, such as mass spectrometry, help confirm the specific identification.
Controlling the spread centers on rigorous infection prevention practices within the hospital environment. Strict adherence to hand hygiene protocols by all healthcare personnel is paramount to prevent transmission from one patient to another. Since C. jeikeium is associated with medical devices, proper sterilization and careful insertion and maintenance of central venous catheters and other invasive lines are necessary. Prompt removal of any infected indwelling device, if clinically feasible, is a critical step in resolving persistent infections.