The genetic material of normal flora could incorporate into bacteria's chromosomes and transfer resistance. Conjugation is not species specific and leads to multiple drug resistance. Use of Antibiotics and Resistance Administering antibiotics when a person is healthy creates resistant bacteria like E. coli. E. coli can conjugate with other harmful bacteria like staphylococcus, streptococcus, etc. Ultimately the over-prescription of antibiotics causes resistance.
Different antibiotics have different spectrums of effectiveness.
Narrow vs. Broad Range Drugs Broad-spectrum drugs wipe out helpful, natural flora, which is why upset stomach, diarrhea, etc. Narrow-spectrum drugs target specific bacteria. Suprainfections are new or secondary infections that develop while treating primary infection. Suprainfections are more likely during the use of broad-spectrum drugs. Host Factors Immune System Patients with compromised immune systems are very difficult to treat.