The Most Effective Ways to Treat Listeria Infections
Listeria is a stealthy, potentially dangerous bacterial agent that is most commonly found in pregnant women. While the mothers-to-be themselves may not be at risk of serious health consequences from the infections, the bacteria travel through maternal cells to reach the fetus, where they negatively impact growth and development. Conventional penicillin treatments are effective against this pathogen, as are some synthetics such as sulfamethoxazole. Because of Listeria's unique way of attacking host cells, however, many other antibiotics are unable to either reach the site of the infection or bind with the bacteria.
Commonly Used Antibiotics
The most commonly prescribed antibiotics for fighting Listeria are in the penicillin group. Penicillin, ampicillin and amoxicillin are capable of penetrating the membranes of the cells lining the GI tract, where Listeria flourishes, without losing their effectiveness at binding to the target receptors on the pathogen's membrane. Pregnant women with Listeria infections are often given abnormally high doses of these antibiotics, as it is important to penetrate the umbilical and placental barriers between the mother's anatomy and the fetus. Sometimes, gentamicin is also administered to aid the penicillin-based agents, but this antibiotic's relatively high toxicity makes this a risky choice for expectant mothers. It is not clear from research that gentamicin increases the other antibiotics' effectiveness.
Special Antibiotic Regimens
Though no wild strain of Listeria has ever been discovered to have a native resistance to penicillin, some patients are unable to take drugs in this group. Those who are allergic to penicillin and related antibiotics face limited treatment options. Trimethoprim combined with sulfamethoxazole offer one of the few non-penicillin-based alternatives for sensitive patients.
Other antibiotics that are capable of penetrating cell walls without losing the ability to disable Listeria include linezolid and rifampin. Cephalosporins have also been examined for their effectiveness. However, each of these has serious limitations. Cephalosporins, for example, do not work well because they don't bind to the correct receptors on Listeria. Rifampin is effective, but the wild strain of Listeria has developed a degree of resistance to it. Linezolid may be effective, but its use during pregnancy has not been extensively researched.
Listeria, though rare, is difficult to identify and treat because of the unique way it spreads through human tissues. The bacillus moves through host cells rather than around them, so the pathogen is able to avoid many of the body's natural defenses. Listeria infections are most common among pregnant women, in whom it may be subtle or entirely asymptomatic, and they can cause severe injury to developing fetuses. Effective treatment of a Listeria infection requires early diagnosis and aggressive treatment with antibiotics.