Antibiotic improve treatment outcome as the combined effect of both antibiotics is better than their individual effect. Methicillin-resistant Staphylococcus aureus infections may be treated with a combination therapy of fusidic acid and rifampicin. Antibiotics used in combination may also be antagonistic and the combined effects of the two antibiotics may be less than if the individual antibiotic was given as part of a monotherapy. For example, chloramphenicol and tetracyclines are antagonists to penicillins and aminoglycosides. However, this can vary depending on the species of bacteria. In general, combinations of a bacteriostatic antibiotic and bactericidal antibiotic are antagonistic. Antibiotics are commonly classified
Discovered attack referred to as a "discovered attack" (or "check") "with capture". When the moving piece moves to a square from which it threatens to inflict checkmate on the next move, the tactic is called a "discovered attack with mate threat". A "discovered checkmate" itself is also possible. In exceptional circumstances, it is possible for the moved piece to give a "double discovered check" (though this name is not actually used). The only way for this to happen in orthodox chess is by way of an "en passant" capture. In the position shown at right, Black has just played 1...g7–g5. White replies