**Core Concept:** Anaerobic bacteria are microorganisms that grow in the absence of oxygen. Anaerobic bacteria can cause infections in various parts of the body, particularly in the gastrointestinal tract, female genital tract, and oral cavity. Streptococci are a group of gram-positive, catalase-negative cocci that can be further classified into facultative and obligate anaerobes. Antibiotics used against streptococci depend on their classification and the specific species involved.

**Why the Correct Answer is Right:** Penicillinase-producing streptococci are a subgroup of streptococci that produce beta-lactamase enzymes, which degrade penicillin, rendering penicillin ineffective. Penicillinase-producing streptococci are predominantly facultative anaerobes. Cephalosporins are beta-lactam antibiotics that are resistant to beta-lactamase enzymes, making them effective against penicillinase-producing streptococci.

**Why Each Wrong Option is Incorrect:**

A. **Incorrect for penicillinase-producing streptococci:** Penicillinase-producing streptococci produce beta-lactamase enzymes, which degrade penicillin, rendering penicillin ineffective. Penicillinase-producing streptococci are predominantly facultative anaerobes. Therefore, penicillin would not be effective against them.

B. **Incorrect for all streptococci:** Cephalosporins are beta-lactam antibiotics that are resistant to beta-lactamase enzymes, making them effective against all streptococci, including penicillinase-producing strains.

C. **Incorrect for facultative streptococci:** Cephalosporins are beta-lactam antibiotics that are resistant to beta-lactamase enzymes, making them effective against penicillinase-producing facultative anaerobes, including facultative streptococci.

D. **Incorrect for obligate anaerobes:** Cephalosporins are beta-lactam antibiotics that are resistant to beta-lactamase enzymes, making them effective against penicillinase-producing obligate anaerobes, including obligate streptococci.

**Clinical Pearl:** Cephalosporins are a valuable therapeutic option against penicillinase-producing facultative and obligate anaerobic bacteria, including penicillinase-producing facultative and obligate streptococci. Cephalosporins are beta-lactam antibiotics that are resistant to beta-lactamase enzymes produced by penicillinase-producing anaerobic bacteria, which allows them to be effective against penicillinase-producing facultative and obligate anaerobic streptococci.

**Core Concept Explanation:** Cephalosporins are beta-lactam antibiotics that are resistant to beta-lactamase enzymes produced by penicillinase-producing anaerobic bacteria,