A Review of SHV Extended-Spectrum β-Lactamases: Neglected Yet Ubiquitous.

Apostolos Liakopoulos,Dik Mevius,Daniela Ceccarelli

doi:10.3389/fmicb.2016.01374

Apostolos Liakopoulos, Dik Mevius + Show 1 more

Open Access

https://doi.org/10.3389/fmicb.2016.01374

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Abstract

β-lactamases are the primary cause of resistance to β-lactams among members of the family Enterobacteriaceae. SHV enzymes have emerged in Enterobacteriaceae causing infections in health care in the last decades of the Twentieth century, and they are now observed in isolates in different epidemiological settings both in human, animal and the environment. Likely originated from a chromosomal penicillinase of Klebsiella pneumoniae, SHV β-lactamases currently encompass a large number of allelic variants including extended-spectrum β-lactamases (ESBL), non-ESBL and several not classified variants. SHV enzymes have evolved from a narrow- to an extended-spectrum of hydrolyzing activity, including monobactams and carbapenems, as a result of amino acid changes that altered the configuration around the active site of the β -lactamases. SHV-ESBLs are usually encoded by self-transmissible plasmids that frequently carry resistance genes to other drug classes and have become widespread throughout the world in several Enterobacteriaceae, emphasizing their clinical significance.

Highlights

Thanks to their ability to inhibit cell wall biosynthesis, β-lactams remained the first-line defense against bacterial infections for over 20 years, before resistant bacteria appeared in clinical practice.Resistance to this class of drugs can be the result of antibiotic target site alteration, prevention of antibiotic access by altered permeability or forced efflux, or antibiotic degradation (Wilke et al, 2005)
The aim of this review is to provide the readers with an updated overview on SHV β-lactamases, their amino acid variants and spectrum of activity, and to describe the occurrence of plasmid-associated SHV enzymes in Enterobacteriaceae and their epidemiological significance
In a few years four other ESBL variants were identified as plasmid-encoded in clinical K. pneumoniae, showing variable gene homologies with the blaSHV-1 and blaSHV-2 sequences (50–90%): blaSHV-2a encoded by conjugative plasmid pZMP1 (Podbielski et al, 1991); blaSHV-3 on pUD18 (Nicolas et al, 1989); blaSHV-4, widely disseminated from France as a result of a single K. pneumoniae clone diffusion (Arlet et al, 1990, 1994); and blaSHV-5 able to hydrolyze broad-spectrum cephalosporins and monobactams (Gutmann et al, 1989)

Summary

A Review of SHV Extended-Spectrum β-Lactamases

SHV enzymes have emerged in Enterobacteriaceae causing infections in health care in the last decades of the Twentieth century, and they are observed in isolates in different epidemiological settings both in human, animal and the environment. Originated from a chromosomal penicillinase of Klebsiella pneumoniae, SHV β-lactamases currently encompass a large number of allelic variants including extended-spectrum β-lactamases (ESBL), non-ESBL and several not classified variants. SHV enzymes have evolved from a narrow- to an extended-spectrum of hydrolyzing activity, including monobactams and carbapenems, as a result of amino acid changes that altered the configuration around the active site of the β -lactamases.

INTRODUCTION

Findings

CONCLUDING REMARKS