Extended spectrum β-lactamases, carbapenemases and mobile genetic elements responsible for antibiotics resistance in Gram-negative bacteria

Abstract

Infectious diseases due to Gram-negative bacteria are a leading cause of morbidity and mortality worldwide. Antimicrobial agents represent one major therapeutic tools implicated to treat these infections. The misuse of antimicrobial agents has resulted in the emergence of resistant strains of Gram-negatives in particular Enterobacteriaceae and non-fermenters; they have an effect not only on a human but on the public health when bacteria use the resistance mechanisms to spread in the hospital environment and to the community outside the hospitals by means of mobile genetic elements. Gram-negative bacteria have become increasingly resistant to antimicrobial agents. They have developed several mechanisms by which they can withstand to antimicrobials, these mechanisms include the production of Extended-spectrum β-lactamases (ESBLs) and carbapenemases, furthermore, Gram-negative bacteria are now capable of spreading such resistance between members of the family Enterobacteriaceae and non-fermenters using mobile genetic elements as vehicles for such resistance mechanisms rendering antibiotics useless. Therefore, addressing the issue of mechanisms of antimicrobial resistance is considered one of most urgent priorities. This review will help to illustrate different resistance mechanisms; ESBLs, carbapenemases encoded by genes carried by mobile genetic elements, which are used by Gram-negative bacteria to escape antimicrobial effect.

Molecular characterization of clinical multidrug-resistant Klebsiella pneumoniae isolates

“…CTX-M has been found to be widely disseminated among clinical Enterobacteriaceae such as Escherichia coli and K. pneumoniae [19], the even higher prevalence of bla CTX-M among our strains corresponds with an earlier report showing that CTX-M–producing strains are generally MDR ones [19]. Furthermore, in line with the previous investigation [20], KPC is highly prevalent among our strains, which also demonstrated that the production of KPC-type carbapenemases was the most prevalent carbapenem resistance mechanism in K. pneumoniae isolates. In addition, the widely distributed 16S-RMTase encoding genes in our MDR strains have been previously reported in China [21], together with AAC (6′)-Ib-cr and AAC (6′)-Ib accounting for the amikacin resistance.…”

Investigation of P Fimbriae Presence in Escherichia coli Strains Isolated from Urine Samples in Human, and Their Antibacterial Resistance

“…However, mobile genetic elements for example plasmids can spread ESBL-related genes via horizontal gene transfer in other Gram-negative bacteria (17). The vast majority of UTIs are caused by a single species of bacteria, and E. coli have been reported as the most frequently isolated infectious agent from UTI in many studies conducted in Turkey and around the world.…”

Prevalence of Aac(6’)-Ib-Cr and Qepa Genes among Quinolone Resistant Uropathogens Isolated from Asymptomatic Female Students of a Northern University on Nigeria.

“…Plasmid-mediated quinolone resistance (PMQR) genes code for low levels of quinolone resistance [29]. The presence of PMQR gene in resistant isolates was 6.75%.…”