Appropriate antibiotics may include ceftriaxone, ciprofloxacin, levofloxacin, or ampicillin/sulbactam. Commonly used antibiotics include ampicillin, ciprofloxacin, ceftriaxone, among others. Amoxicillin, ampicillin, and erythromycin may also be used for severe cases. Tetracycline, ampicillin, and amoxicillin can also be used in such cases. Sensitive strains of these bacteria can be treated with ampicillin, penicillin and vancomycin. Most "S. suis" strains respond to treatment with ampicillin and amoxicillin. Reports of successful treatment with parenteral penicillin or ampicillin exist. Treatment is with penicillin, ampicillin, tetracycline, and co-trimoxazole for one to two years. Currently recommended antibiotics include clindamycin, meropenem, ertapenem, ampicillin/sulbactam, and moxifloxacin. Daptomycin or linezolid may also show efficacy in case ampicillin and vancomycin resistance. Treatment is typically with antibiotics such as clindamycin, meropenem, ampicillin/sulbactam, or moxifloxacin. The strain is natively resistant to both spectinomycin and ampicillin antibiotics. So, for example, the "marker gene" could be for resistance to the antibiotic ampicillin. It has also been shown to be susceptible to ampicillin & ceftriaxone. "C. freundii" strains have inducible "ampC" genes encoding resistance to ampicillin and first-generation cephalosporins.