Which of the following antibiotics is Group B streptococci resistant to?

Group B streptococci (GBS), particularly Streptococcus agalactiae, are notably resistant to bacitracin, which is primarily used against Group A streptococci. This resistance is significant in a clinical context, as bacitracin is not effective in treating infections caused by GBS.

In contrast, other antibiotics listed, such as penicillin and vancomycin, are effective against Group B strep. Penicillin is often the drug of choice for treating infections caused by this bacterium, and vancomycin can be utilized in cases of resistance to penicillin. Gentamicin can also be used in some cases, especially in combination therapy.

Understanding the antibiotic resistance profiles of different bacterial species is crucial for selecting appropriate treatments in clinical settings, as it helps in managing infections effectively.