From the Guidelines
Lactobacilli appear as slender, rod-shaped (bacilli) bacteria when viewed under a wet mount microscope. They typically measure about 0.5-1.5 μm in width and 1.0-10.0 μm in length. These gram-positive organisms often arrange themselves singly or in short to medium-length chains, and occasionally may appear slightly curved rather than perfectly straight. Under wet mount conditions, lactobacilli are non-motile, meaning they do not move independently through the fluid. The lack of motility helps distinguish them from other rod-shaped bacteria that may be motile. In vaginal samples, lactobacilli are particularly abundant and important as they maintain vaginal health by producing lactic acid, which creates an acidic environment (pH 3.8-4.5) that inhibits the growth of pathogenic organisms, as noted in the context of bacterial vaginosis diagnosis and treatment 1. This morphological appearance is consistent across most Lactobacillus species, though slight variations in length and arrangement may occur between different species within this genus. Some key features to note when observing lactobacilli under a wet mount microscope include:
- Their rod-shaped morphology
- Non-motility
- Arrangement in singles or short chains
- Production of lactic acid contributing to an acidic vaginal environment, which is crucial for maintaining vaginal health and preventing conditions like bacterial vaginosis, as discussed in guidelines for sexually transmitted diseases treatment 1.
From the Research
Morphology of Lactobacilli
- Lactobacilli are typically rod-shaped bacteria, but their morphology can vary depending on the species and environmental conditions.
- Under a wet mount microscope, Lactobacilli may appear as long, thin rods with rounded ends, often in chains or clusters 2, 3.
- The size and shape of Lactobacilli can range from 0.5-1.5 μm in width and 2-10 μm in length, with some species exhibiting more irregular shapes or arrangements 4, 5.
- In vaginal samples, Lactobacilli may be observed alongside other microorganisms, such as yeast or other bacteria, and their morphology can be influenced by the presence of these other organisms 6.
Observations Under Wet Mount Microscope
- When viewed under a wet mount microscope, Lactobacilli may exhibit characteristic motility patterns, such as twitching or jerking movements, although some species may be non-motile 2, 3.
- The wet mount technique can also reveal the presence of other vaginal microorganisms, such as Trichomonas or Candida, which can help in diagnosing vaginal infections 4, 5.
- However, it is essential to note that the morphology of Lactobacilli under a wet mount microscope may not always be distinctive or easily identifiable, and additional diagnostic techniques, such as Gram staining or molecular testing, may be necessary for accurate identification 6.