Stefania Stefani, LabMMAR - Department of Biomedical and Biotechnological Sciences, University of Catania, Italy

Dynamics of antibiotic resistance and probiotic strategies

The antibiotic era started in 1928, when a piece of mold contaminating a petri dish in a laboratory in England, become famous for its ability to produce penicillin, the first antibiotic able to kill bacteria. In the revolutionary time that followed this discovery, the feeling to be finally able to cure all infections, also deadly illnesses such as pneumonia or tuberculosis, and to become the bedrock of many of the greatest medical advances was permeating the medical community. This golden era of antibiotics was successfully followed by the introduction of many other compounds together with many attempts to understand and improve their use by dosing, administration and many other biochemical and physiological advances. However, the nightmare started almost immediately, just a few years later, with the discovery of bacteria producing an enzyme, a penicillinase, able to inactivate penicillin, considered at that time still a magic bullet. From that moment, bacteria and other pathogens have always evolved so that they can resist the new drugs that medicine has used to combat them. Resistance has increasingly become a problem in recent years because the pace at which we are discovering new antibiotics has slowed dramatically, while antibiotic use is increasing. The successful use of any therapeutic agent is compromised by the potential development of tolerance or resistance to that compound. Antimicrobial resistance is a cause of death in 700,000 cases (probably an underestimation) per year and the forecast for 2050 is quoted at around 10 million people dying, with different types of impact in terms of etiological agents, geography and prevalence in the diverse parts of the globe. Resistance arises as a consequence of mutations and/or acquisition of new determinants in microbes and selection pressure from antibiotic use providing a competitive advantage for these mutated strains. Suboptimal antibiotic doses help stepwise selection of resistance. The global spread of antibiotic resistance is a major problem not only for humans, but also for animal health and general welfare. The impact of clinically relevant antibiotic resistance genes and antibiotic resistant bacteria released from anthropogenic sources, together with the excessive use of antibiotics in both human and veterinary settings, is currently considered to be a serious emerging environmental problem. Antibiotic resistance hotspots are not only found in medical settings, but also in environmental compartments such as municipal wastewater systems, animal husbandry facilities, and farms. Characterized by extremely high bacterial loads coupled to the presence of sub-therapeutic concentrations of antibiotics, these sites are also responsible for the discharge of MDR bacteria and antibiotic resistance genes into the environment. Then decreasing effectiveness of antibiotics and the arrival of untreatable strains of bacteria put us at the dawn of a post-antibiotic era. The problem is enormous and can be solved collectively in different directions: i) new drugs, new vaccines, but also new strategies to combat infections (Probiotics and “good or helpful” bacteria); ii) global action plans such as the one organized by the WHO; iii) advances in genetics, genomics, and computer science. One of the strategies for a good success is the use of “good or helpful bacteria”. Although more research is needed, there are encouraging evidences that probiotics may help to:

All the approaches above mentioned will likely change the way that infections and new types of resistance are diagnosed, detected and reported worldwide, so that we can fight back faster when bacteria evolve to resist drugs.


Prof. Stefania Stefani - Bio sketch

Stefania Stefani is currently Full Professor of Microbiology in the Department of Bio-Medical and Biotechnological Sciences, University of Catania, Italy. She also acts as a consultant at the University Hospital, under contract with the Cannizzaro Hospital for advanced molecular diagnostics. Professor Stefani has served on several committees and boards including the Board of Trustees of the International Society of Chemotherapy, Italian Society of Clinical Microbiology and American Society for Microbiology. She is also a member of the subcommittee for antimicrobial resistance of the European Society of Clinical Microbiology and Infectious diseases (ESCMID). Professor Stefani has served on several committees and boards including the Board of Trustees of the International Society of Chemotherapy, Italian Society of Clinical Microbiology and American Society for Microbiology. She is also a member of the subcommittee for antimicrobial resistance of the European Society of Clinical Microbiology and Infectious diseases (ESCMID). Stefania Stefani has published more than 100 papers in peer-reviewed international journals and has been an invited speaker in national and international congresses of microbiology, infectious diseases and chemotherapy. Professor Stefani is Editor-in-Chief of the Journal of Global Antimicrobial Resistance as well as serving on the editorial scientific board for multiple journals including International Journal of Antimicrobial Agents, Annals of Microbiology and Microbiology. She has experience as principal investigator of projects funded by national and international grant agencies. Her research is focused on the study of the mechanisms of resistance in Gram positive and Gram negative bacteria, epidemiology of resistant microorganisms, and surveillance studies.

  1. Berendonk TU, Manaia CM, Merlin C, Fatta-Kassinos D, Cytryn E, Walsh F, Bürgmann H, Sørum H, Norström M, Pons MN, Kreuzinger N, Huovinen P, Stefani S, Schwartz T, Kisand V, Baquero F, Martinez JL. Tackling antibiotic resistance: the environmental framework. Nat Rev Microbiol. 2015 Mar 30. doi: 10.1038/nrmicro3439. [Epub ahead of print] PubMed PMID: 25817583.
  2. Iannelli F, Santagati M, Santoro F, Oggioni MR, Stefani S, Pozzi G. Nucleotide sequence of conjugative prophage Φ1207.3 (formerly Tn1207.3) carrying the mef(A)/msr(D) genes for efflux resistance to macrolides in Streptococcus pyogenes. Front Microbiol. 2014 Dec 9;5:687. doi: 10.3389/fmicb.2014.00687. eCollection 2014. PubMed PMID: 25538698; PubMed Central PMCID: PMC4260502.
  3. Mishra NN, Bayer AS, Weidenmaier C, Grau T, Wanner S, Stefani S, Cafiso V, Bertuccio T, Yeaman MR, Nast CC, Yang SJ. Phenotypic and genotypic characterization of daptomycin-resistant methicillin-resistant Staphylococcus aureus strains: relative roles of mprF and dlt operons. PLoS One. 2014 Sep 16;9(9):e107426. doi: 10.1371/journal.pone.0107426. eCollection 2014. PubMed PMID: 25226591; PubMed Central PMCID: PMC4166420.
  4. Corno G, Coci M, Giardina M, Plechuk S, Campanile F, Stefani S. Antibiotics promote aggregation within aquatic bacterial communities. Front Microbiol. 2014 Jul 1;5:297. doi: 10.3389/fmicb.2014.00297. eCollection 2014. PubMed PMID: 25071728; PubMed Central PMCID: PMC4077313.
  5. Mezzatesta ML, Caio C, Gona F, Cormaci R, Salerno I, Zingali T, Denaro C, Gennaro M, Quattrone C, Stefani S. Carbapenem and multidrug resistance in Gram-negative bacteria in a single centre in Italy: considerations on in vitro assay of active drugs. Int J Antimicrob Agents. 2014 Aug;44(2):112-6. doi: 10.1016/j.ijantimicag.2014.04.014. Epub 2014 Jun 2. PubMed PMID: 25059444.