Provided herein are compositions comprising substantially non-viable Gram-negative bacterial organisms that have a substantial reduction in endotoxin activity andor pyrogenicity and methods for treating a cancer using the same. The housing comprises a base portion, a plurality of passageways defined in the base portion, a pair of retention portions at a pair of ends thereof. A first differential pressure transducer is coupled to the pitot-tube section for producing signals representative of velocity of the airwater spray at the orifice.