When comparing results, the students note that Staphylococcu…

When comparing results, the students note that Staphylococcus aureus (Gram-positive) is Susceptible to Penicillin, but the Gram-negative Pseudomonas aeruginosa is Resistant. What structural difference in P. aeruginosa most effectively explains why it can resist many antibiotics (like Penicillin) that easily kill S. aureus?

Although the observed bright pink rods provide strong presum…

Although the observed bright pink rods provide strong presumptive evidence of TB infection, a definitive diagnosis cannot be made from this stain alone. What is the next essential and mandatory laboratory procedure that must be performed on the original sputum sample before the patient can be definitively diagnosed and a course of specific antibiotic treatment is initiated?