From the Research
Small gram-positive bacilli include Listeria monocytogenes, Corynebacterium species (including C. diphtheriae), Lactobacillus species, Erysipelothrix rhusiopathiae, and Gardnerella vaginalis, as identified in the most recent study 1. These bacteria are characterized by their rod-shaped morphology and positive staining with crystal violet during the Gram staining procedure, which indicates a thick peptidoglycan layer in their cell walls. Some key points to consider when dealing with these bacteria include:
- Listeria is notable for causing listeriosis, particularly dangerous in pregnant women and immunocompromised individuals.
- Corynebacterium diphtheriae causes diphtheria and displays a distinctive club-shaped appearance and metachromatic granules.
- Lactobacilli are part of the normal flora in the vagina and gastrointestinal tract, contributing to a healthy microbiome.
- Erysipelothrix causes erysipeloid, an occupational infection in those handling animal products.
- Gardnerella is associated with bacterial vaginosis. These bacteria can be distinguished from other gram-positive organisms by their smaller size and bacillary (rod) shape compared to larger bacilli like Bacillus or Clostridium species. It's also important to note that patient variables such as malignancy, sepsis, peptic ulcer disease, and immunosuppression can increase the likelihood of pathogenic Gram-positive bacilli being isolated from blood cultures 1. In terms of treatment, antibiotic susceptibility testing is necessary to determine the best course of action, as these bacteria can exhibit varying levels of resistance to different antibiotics 2, 3, 4.