A Gram stain showing gram-positive cocci in pairs, or diplococci, is a morphological characteristic of several bacteria. Gram stains can be positive or negative, depending on the cell wall composition of the bacteria. Morphologies in Gram stains include cocci, rods, coccobacilli and spirochetesKnow More
The most common gram-positive cocci that form pairs include most Streptococcus species, Listeria and Enterococcus bacteria. All of these organisms can cause infections in humans. Accurate identification of the bacteria is essential for proper antibiotic treatment.
Streptococcal bacteria can cause a variety of infections that target multiple organ systems, including strep throat, pneumonia and necrotizing fasciitis. Along with Listeria monocytogenes, it can also cause meningitis in newborns and those with compromised immune systems. Listeria can be found on contaminated food that has not been properly cleaned prior to ingestion. Both Streptococcus and Listeria have Gram stain morphologies of cocci pairs or short chains.
Enterococcus species look similar to Steptococcus bacteria and both are found naturally in the human intestinal tract. In the past, Enterococci bacteria were classified as Group D Streptococci before being distinguished in their own genus. Enterococcus species have higher rates of antibiotic resistance compared to Streptococcus and Listeria, and typically require more aggressive antibiotic therapies.Learn more about Biology
Antibiotics are generally effective in treating gram-positive cocci bacteria, according to Merck Manuals. However, some strains have developed a resistance to antibiotics. For example, methicillin-resistant Staphylococcus aureus, or MRSA, is resistant to many antimicrobials, including penicillin and amoxicillin, explains Drugs.com. Alternative antibiotics used to treat MRSA include linezolid, clindamycin and vancomycin.Full Answer >
Cocci bacteria are bacteria that are spherical or oval in shape. The three basic shapes of bacteria are coccus, bacillus and spiral. Cocci bacteria can form arrangements that have different names.Full Answer >
The bacillus Subtilis gram stain is a way to test if a patient is infected by the bacteria. Bacillus Subtilis is an endospore.Full Answer >
Gram-negative rods, or bacilli, are rod-shaped bacteria that give a negative result with Gram staining. These bacteria have a thin peptidoglycan layer sandwiched between the inner and outer cell membrane. This layer is removed when the bacterial cells are washed with an alcohol solution so they do not retain the crystal violet stain first applied. Instead, the cells turn red or pink with the safranin or fuchsine counterstain.Full Answer >