لخّصلي

The lactam groups of molecules are integrated into four families, i.e., beta-lactam [11], gamma-lactam [12], delta-lactam [13], and epsilon-lactam [14], with a specific action and not necessarily like antibiotics. Specifically, the beta-lactams drugs show antibiotic effects in a wide bacterial variety. They are characterized by a beta-lactam ring presence, which confers the antimicrobial effect by the transpeptidases and carboxypeptidases inactivation (the proteins responsible for the biosynthesis of the cell wall) through their binding to Penicillin Binding Protein (PBPs) receptors [15].
The beta-lactam family is made up of various members, such as penicillins B and G, amoxicillin, ampicillin, cephalosporins (cephalothin, cephalexin, ceftriaxone, and cefepime), carbapenems (imipenem, meropenem, ertapenem), aztreonbactam, monobactam, and some others.
The indiscriminate and unconscious use of these antibiotics in daily clinical practice has caused an increase in multiresistant Enterobacteriaceae strains, especially Escherichia coli and Klebsiella pneumoniae, turning this situation into a serious global health problem [16]. During the last decade that there has been a significant increase in the presence of multi-resistant strains worldwide, mainly in the European Union.
The European Read for Antimicrobial Resistance Surveillance (EARSNet) has been identified pan-resistant Escherichia coli and Klebsiella pneumoniae strains [17,18].
The bacteria have various resistance mechanisms, mainly associated with plasmid assimilation, which allow cross-resistance against a wide range of antibiotics [19]. The most widely described mechanism of antibiotic resistance that is mediated by plasmid transfer is the enzymatic degradation of the beta-lactam ring through the expression of beta-lactamases [20].
The genes encoding for the beta-lactamases enzymes have been widely spread among the bacterial population, through mobile genetic elements, which confer a plasmid-mediated multi-resistance [21,22]. These multi-resistance bacteria complicate the patient treatments and condition the type of antibiotics that can be administrated for the treatment of common infections [23]. The first-line antibiotic treatment regimens for gastrointestinal and airway infections usually include beta-lactams drugs, such as ampicillin, amoxicillin, or third generation cephalosporins (Ceftriaxone), but the resistance determines the treatment that can be given to patients and decreases the effectiveness significantly of these treatments.
The Carbapenems (ertapenem, meropenem, imipenem) have been widely used as an alternative for the treatment of these resistant bacteria, however, in recent years, resistant bacteria strains to these antibiotics have been identified [24]. The main causes associated with this increase in bacterial resistance are the error in the medical prescription, self-medication, incomplete antibiotics treatment, and the use of these drugs by the agricultural and livestock industry for the treatment of crops for human consumption
For these reasons, we test the hypothesis that the Enterobacteriaceae integrating the human gastrointestinal microbiome are carriers of beta-lactamases genes in healthy individuals who have not received antibiotic treatment during their last year of life.