Enterobacter cloacae is a type of bacterium that can cause infections, particularly in healthcare settings. This bacterium is characterized as Gram-negative, rod-shaped, and a facultative anaerobe, meaning it can thrive with or without oxygen. While often found as part of the normal gut flora in a significant portion of the human population, it primarily acts as an opportunistic pathogen. This means it typically causes illness in individuals who are already weakened or have underlying health conditions.
Where Enterobacter cloacae Resides
Enterobacter cloacae is widely distributed in nature, thriving in various environments. It is commonly found in soil, water sources, sewage, and plants.
This bacterium is a common inhabitant of the gastrointestinal tract of both humans and animals, where it often exists harmlessly as a commensal organism. Estimates suggest that Enterobacter cloacae can be part of the normal intestinal flora in 40% to 80% of people. This widespread presence in the gut means individuals can carry the bacterium without experiencing symptoms.
Healthcare environments represent another significant reservoir for Enterobacter cloacae. Hospitals, especially intensive care units, are known locations where this bacterium is frequently isolated. It can persist on various hospital surfaces and medical equipment, including catheters and ventilators.
The bacterium’s ability to survive in these settings makes it a common source of healthcare-associated infections. It has been found contaminating infusion solutions, total parenteral nutrition solutions, and even blood products.
How Enterobacter cloacae Spreads
Enterobacter cloacae primarily spreads through direct and indirect contact. Direct contact involves transmission from person to person, such as from a healthcare worker to a patient. Indirect contact occurs when individuals touch contaminated objects or surfaces.
Healthcare-acquired infections are the most common way people contract this organism. This is often facilitated by the bacterium’s presence on medical devices. Catheters, ventilators, drainage tubes, and central venous catheters can all become contaminated and serve as routes for infection.
The bacterium can enter the body through different sites, including the skin, urinary tract, or gastrointestinal tract. Contaminated intravenous fluids, total parenteral nutrition solutions, and blood products have also been linked to outbreaks.
In some cases, infections arise from the patient’s own body. Enterobacter cloacae can translocate from the gastrointestinal tract to other parts of the body, particularly in debilitated individuals. While less common for serious infections, ingestion of contaminated food or water can also be a route of exposure.
Factors Increasing Susceptibility
Several factors increase susceptibility to Enterobacter cloacae infection. A weakened immune system increases the risk. Conditions like malignancy, HIV/AIDS, organ transplantation, or chemotherapy compromise the body’s defenses.
Underlying medical conditions also predispose individuals to infection. Patients with diabetes, severe burns, chronic kidney disease, chronic obstructive pulmonary disease, or gastrointestinal ulcers face higher susceptibility. These pre-existing health issues can create an environment where opportunistic pathogens like Enterobacter cloacae can thrive.
Prolonged hospitalization, especially admission to an intensive care unit (ICU), is a recognized risk factor. Hospitalized patients often have compromised health and are exposed to a higher concentration of pathogens.
Invasive medical procedures, such as surgery or intubation, increase the risk by providing direct entry points for bacteria. The presence of invasive medical devices, including central venous catheters, drainage tubes, and mechanical ventilation, further elevates susceptibility. These devices can bypass natural protective barriers, allowing bacteria to colonize and cause infection.
Prior antibiotic use can also contribute to increased susceptibility. Antibiotics can disrupt the normal balance of beneficial bacteria in the body, creating an opportunity for resistant strains of Enterobacter cloacae to multiply. This selective pressure can lead to the emergence of multidrug-resistant forms. Extremes of age, such as neonates and the elderly, are also vulnerable due to their developing or declining immune systems.