Detection of the SHV genotype polymorphism of the extended-spectrum β-lactamase-producing Gram-negative bacterium

Abstract

Abstract. The prevalence of extended-spectrum β-lactamases (ESBLs) is due to the extensive usage of the extended-spectrum cephalosporins and leads to huge financial loss worldwide, whilst presenting a challenge to the clinical treatment. The aim of the present study was to delineate the frequency of ESBL occurrence in Enterobacteriaceae and confirm the SHV genotype. A random collection of 153 Escherichia coli isolates (E. coli) and 70 Klebsiella pneumoniae isolates were tested. The amplification products obtained by polymerase chain reaction were sequenced. Isolates with novel mutations were transformed to E. coli DH5α. The minimum inhibitory concentration (MIC) was obtained by a microdilution method. The relevance ratio of ESBL was 67.7% and the proportion of the SHV β-lactamase gene (bla SHV ) was 18.5%. A new genotype of β-lactamase was demonstrated and submitted to GenBank. A total of 12 mutational sites were found in 28 ESBL-producing isolates, including four nonsense mutations. Sensitive-rates of 28 ESBL-producing isolates to imipenem were 100%, and resistant-rates to penicillin, amoxicillin and oxacillin were 100%. The MIC of DH5α-F8 to penicillin, oxacillin, cefoxitin, cefotaxime, cefepime, cefoperazone/sulbactam, imipenem and netilmicin was 512, 512, 2, 0.03, 0.06, 4, 0.015 and 32 respectively. In conclusion, ESBL and SHV-28 is the most prevalent bla. Imipenem is the most effective antibiotic to ESBL, and the 4th-generation cephalosporins and β-lactamase inhibitor compound are also effective. ESBL is mediated by plasmids and able to spread among different Enterobacteriaceae. In conclusion, new mutations of the bla SHV gene exist from at least 2010.

Nosocomial infection and its molecular mechanisms of antibiotic resistance

“…Like the TEM family, members of the SHV family have certain amino acid mutations at the active site. More than fifty members of the SHV family recently have been identified through unique combinations of amino acid replacements (24). The SHV family recently has been shown in surveys of resistant strains in Europe and America (25,26).…”

Genetic basis of molecular mechanisms in β-lactam resistant gram-negative bacteria

“…The SHV-type ESBL enzymes evolved via point mutation from classical plasmid-encoded enzyme SHV-1, which has a limited hydrolytic capacity for extended-spectrum cephalosporins [36]. [37] [33,38]. The replacement of an amino acid found in an inhibitor-resistant SHV isolate (S130G in the SHV class-A β lactamase, for instance) causes resistance to inhibition by avibactam, a unique non-β-lactam β-lactamase inhibitor.…”

Detection of Multidrug-resistant Extended-spectrum Beta-lactamase-producing Enterobacteria from Community Infections in the city of Reynosa, Tamaulipas Mexico

“…ESBLs belong to classes A and D of Ambler's beta-lactamases classi cation and are characterized by containing a serine residue in its active site, in addition to being strongly inhibited by classical inhibitors such as clavulanic acid [10]. ESBLs groups includes nine structural families: TEM, SHV, CTX-M, PER, VEB, GES, TLA, BES and OXA [11]. The TEM, SHV and CTX-M families are the most prevalent worldwide reported in hospital and community infections [6,12,13].…”

“…The TEM, SHV and CTX-M families are the most prevalent worldwide reported in hospital and community infections [6,12,13]. ESBLs contained in conjugative plasmids facilitate their mobility through horizontal gene transfer [11,14,15] and in turn, these plasmids may contain resistance related genes to other antibiotics, such as quinolones, aminoglycosides, tetracyclines and even colistin, which increases the chances of failure in treatment schemes [16,17,18]. ESBL-producing Enterobacteriaceae were originally associated with infections related to the hospital environment, however, cases of community-associated infections have increased [5], and ESBL-producing Enterobacteriaceae have been reported in sources, such as water, soil, livestock, pets and in healthy human carriers [15,19].…”