From the Research
Gram-positive coccobacilli are bacteria that appear as short rods with rounded ends when viewed under a microscope, and they retain crystal violet dye during Gram staining due to their thick peptidoglycan cell wall. These bacteria fall between true cocci (spherical) and bacilli (rod-shaped) in morphology. Common examples include Listeria monocytogenes, which causes listeriosis; Gardnerella vaginalis, associated with bacterial vaginosis; and some Corynebacterium species. These organisms can be clinically significant as they may cause various infections depending on the specific species. Listeria, for instance, can cause serious foodborne illness, particularly dangerous for pregnant women, newborns, and immunocompromised individuals, as noted in a study published in the British journal of hospital medicine 1. The thick peptidoglycan layer in their cell walls makes them generally more susceptible to antibiotics like penicillins and cephalosporins compared to Gram-negative bacteria. Proper identification of these organisms through Gram staining and culture is essential for appropriate antibiotic selection and treatment of infections they cause.
Some key characteristics and examples of gram-positive coccobacilli include:
- Listeria monocytogenes, a cause of listeriosis, which can be treated with penicillin-based therapy in combination with gentamicin, as advised in a study published in the British journal of hospital medicine 1
- Gardnerella vaginalis, associated with bacterial vaginosis
- Corynebacterium species, which can cause various infections
It's worth noting that antibiotic resistance is a concern, as seen in a study published in the Journal of infection and public health, where 145 strains of Listeria monocytogenes revealed multidrug-resistance 2. However, the most recent and highest quality study, published in 2021, recommends penicillin-based therapy in combination with gentamicin for invasive infection, and co-trimoxazole may be considered for patients intolerant to penicillin 1. This recommendation prioritizes morbidity, mortality, and quality of life as the outcome, and is based on the most recent evidence available.
In terms of treatment, it's essential to consider the potential for antibiotic-resistant L-form cells, as observed in a study published in Frontiers in cellular and infection microbiology 3. However, the current recommendation for treating Listeria monocytogenes infections is to use penicillin-based therapy in combination with gentamicin, as this has been shown to be effective in reducing morbidity and mortality 1.
Overall, gram-positive coccobacilli are an important group of bacteria that can cause significant infections, and proper identification and treatment are crucial to reducing morbidity and mortality. The use of penicillin-based therapy in combination with gentamicin is currently the recommended treatment for invasive Listeria monocytogenes infections, based on the most recent and highest quality evidence available 1.