Ampicillin: rise fall and resurgence.

Antimicrobial resistance (AMR) is a global problem. AMR has posed new challenges in treatment of infectious diseases. Antimicrobials are losing efficacy due to development of resistant pathogens. It has lead to re-emergence of certain infectious diseases. Treatment of such diseases has undergone changes with use of alternative antimicrobials and drug combinations. Pathogens are likely to develop resistance to alternative antimicrobials also and risk of infections with nonexistent treatment is real. Salmonella showed widespread resistant to ampicillin which resulted in use of alternative antimicrobials like fluroquinolones and cephalosporins in the treatment of enteric fever in last two decades. Unfortunately there are growing reports of resistance to these antimicrobials. Interestingly there are numerous reports of ampicillin regaining activity against Salmonella. Speculatively lack of exposure of Salmonella to ampicillin for long time resulted in the loss of plasmid mediated resistance in the pathogen. There may have been emergence of de novo ampicillin susceptible strains. This is assuring in the era where problem of AMR is compounded by the scarcity of new antimicrobial development.