Which one of the following is NOT correct about antibiotic resistance mechanism in microbes?
1
Mycoplasma is naturally resistant to penicillins due to presence of R plasmid.
2
Gram - negative bacteria are impermeable to penicillin G.
3
β - lactamases of bacteria can cleave penicillins.
4
Selective microbes can efflux penicillins entering the cell and develop resistance.