Treatment is dependent on which species or strain of<unk>  is found in a given patient. While<unk>  species are susceptible to a number of standard antibiotics in vitro — macrolides and tetracycline, for example — the efficacy of antibiotic treatment in immunocompetent individuals is uncertain. Immunocompromised patients should be treated with antibiotics because they are particularly susceptible to systemic disease and bacteremia. Drugs of particular effectiveness include trimethoprim-sulfamethoxazole, gentamicin, ciprofloxacin, and rifampin; B. henselae is generally resistant to penicillin, amoxicillin, and nafcillin.
Bartonella
Salmonella
Cryptosporidium
Listeria monocytogenes
Legionella
Mycoplasma
Edwardsiella 
Yersinia pestis