Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1275122 (TEM)
 21,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present investigation was undertaken to assess the prevalence of extended-spectrum beta-lactamases (ESbetaLs) among urinary tract infection (UTI) isolates. During 4 months in 2004, a total of 650 Enterobacteriaceae strains from UTIs was collected by five clinical microbiology laboratories located in southern Italy and the beta-lactamase production was investigated. A total of 50 of the 650 isolates were double-disk positive and suspected of producing an ESbetaL; Escherichia coli (36.0%) and Klebsiella pneumoniae (32.0%) were the most common species among all ESbetaL producers. Characterization of ESbetaL determinants was carried out by the colony blot hybridization method, and polymerase chain reaction (PCR) and DNA sequencing in order to identify the presence of bla (TEM), bla (SHV), bla (PER), and bla (CTX-M) determinants. The ESbetaL variants found in this study were the following: TEM-15, TEM-24, TEM-52, TEM-134, SHV-12, CTX-M-1, CTX-M-3, CTX-M-15, and PER-1. As expected, the majority of the isolates were found to be susceptible to imipenem (94%), cefepime (54%) and piperacillin-tazobactam (54%). The results of this survey show the prevalence of ESbetaL enzymes among enterobacterial pathogens causing UTIs in southern Italy.
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PMID:Occurrence of extended spectrum beta-lactamases among isolates of Enterobacteriaceae from urinary tract infections in southern Italy. 1722 11

By studying the beta-lactamase content of several Acinetobacter spp. isolates from Argentina, producing the expanded-spectrum beta-lactamases (ESBL) VEB-1a or PER-2, a novel Ambler class A beta-lactamase gene was identified. It encoded the narrow-spectrum beta-lactamase SCO-1, whose activity was inhibited by clavulanic acid. SCO-1 hydrolyzes penicillins at a high level and cephalosporins and carbapenems at a very low level. beta-Lactamase SCO-1 was identified from unrelated VEB-1a-positive or PER-2-positive Acinetobacter spp. isolates recovered from three hospitals. The bla(SCO-1) gene was apparently located on a plasmid of ca. 150 kb from all cases but was not associated with any ESBL-encoding gene. The G+C content of the bla(SCO) gene was 52%, a value that does not correspond to that of the A. baumannii genome (39%). beta-Lactamase SCO-1 shares 47% amino acid identity with CARB-5 and ca. 40% with the enzymes TEM, SHV, and CTX-M. A gene encoding a putative resolvase was identified downstream of the bla(SCO-1) gene, but its precise way of acquisition remains to be determined.
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PMID:Identification of the novel narrow-spectrum beta-lactamase SCO-1 in Acinetobacter spp. from Argentina. 1742 Feb 13

PER-2 was the first detected and the second most prevalent extended-spectrum beta-lactamase in clinical pathogens isolated in Argentina and was also reported only in other South American countries. Citrobacter freundii 33587 was isolated in 1999 in Buenos Aires and was resistant to all tested beta-lactams except cephamycins and carbapenems. The strain produced both plasmid-borne TEM-1 and PER-2 (pI 5.4), which could be transferred by conjugation. By PCR screening, thermal asymmetric interlaced PCR, and DNA sequencing, we detected an ISPa12/IS1387a insertion sequence upstream of bla(PER-2), previously reported as also being associated with bla(PER-1). The presence of similar structures upstream of bla(PER-1) and bla(PER-2) suggests a common origin and mobilization. Compared to bla(PER-1) genes, an additional putative promoter for bla(PER-2) was found. PER-2 kinetic analysis showed its high hydrolysis efficiencies toward both CTX and CAZ (k(cat)/K(m), 0.76 and 0.43 microM(-1).s(-1), respectively).
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PMID:Biochemical characterization of PER-2 and genetic environment of blaPER-2. 1743 50

Resistance to antibiotics may drastically diminish the efficacy of therapy in some clinical circumstances. The emergence of Enterobacteriaceae (Klebsiella pneumoniae, Aerobacter aerogenes, Escherichia coli) resistant to the more recent beta-lactam agents (cefepime, cefpirome, azthreonam and carbapenems) generally results from misuse of antibiotics, leading to the selection of preexisting resistant mutants. Resistance is usually due to beta-lactamase expression, through: -- mutations involving the beta-lactamase structure (TEM, SHV, OXA, CTX-M beta-lactamase families) and/or mutations of beta-lactamase synthesis regulators (AmpC beta-lactamases); or -- the appearance of new enzymes (PER, VEB, CMY, DHA-1, ACC-1, etc.). The level of resistance (particularly to carbapenems) is increased when porin mutations are associated with beta-lactamase expression. The spread of these new resistance mechanisms is amplified by mobilisation of resistance genes from the chromosome to a plasmid (SHV, CTX-M, CMY DHA-1 beta-lactamases genes) and by the location of these genes in mobile elements (integrons and transposons). The recent appearance of these mechanisms (particularly CTX-M beta-lactamases) in strains circulating in the community is a matter of concern.
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PMID:[Resistance to the latest beta-lactams: mechanisms of acquisition and spread of resistance in Enterobacteriaceae]. 1764 6

Extended-spectrum beta-lactamases (ESBLs) are usually plasmid-mediated enzymes that confer resistance to a broad range of beta-lactams. Initially, resistance to third-generation cephalosporins in Gram-negative rods was mainly due to the dissemination of TEM- and SHV-type ESBLs, which are point mutants of the classic TEM and SHV enzymes with extended substrate specificity. During the last ten years, CTX-M-type ESBLs have become increasingly predominant, but less frequent class A beta-lactamases have also been described, including SFO, BES, BEL, TLA, GES, PER and VEB types. While several of these latter are rarely identified, or are very localised, others are becoming locally prevalent, or are increasingly isolated worldwide. In addition, mutations can extend the spectrum of some OXA-type beta-lactamases to include expanded-spectrum cephalosporins, and several of these enzymes are considered to be ESBLs.
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PMID:Minor extended-spectrum beta-lactamases. 1815 27

Genes encoding extended-spectrum beta-lactamases (ESBLs) have been reported in a variety of Gram-negative species, mostly in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. They are mostly either TEM or SHV derivatives, CTX-M-like enzymes--now emerging worldwide--or, less frequently, VEB, GES, and PER ESBLs. The mechanisms responsible for their acquisition are very diverse, and mostly are related to insertion sequences (ISs), transposons, class 1 integrons, and also sul1-type integrons containing the ISCR1 element. This diversity of genetic vehicles at the origin of these mobilisation/acquisition processes enhances the spread of ESBLs.
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PMID:Genetic support of extended-spectrum beta-lactamases. 1815 30

We studied the antibiotic resistance among Escherichia coli isolates obtained from fecal samples of dogs and cats treated and untreated with enrofloxacin in veterinary clinics. Resistant patterns of 70 strains and the presence of extended-spectrum beta-lactamase (ESBL) were studied. The genes encoding the following families of beta-lactamases: CTX-M, GES, PER, TEM and SHV, were investigated by PCR-RFLP and sequencing. The strains isolated from enrofloxacin-treated animals were multi-drug-resistant exhibiting resistant patterns including fluorquinolones, beta-lactams, aminoglycosides, tetracycline and phenicols. On the contrary, the strains obtained from the untreated group of animals exhibited narrower antibiotic resistant profiles. The synthesis of ESBL was detected in 14 strains (20%) isolated from treated animals. The ESBL encoded by genes bla CTX-M-1, bla CTX-M-9 group and bla PER-2 were detected by PCR. We believe that this is the first report on the presence of ESBL in E. coli strains isolated from small animals in Chile, and the first report of beta-lactamase belonging to the CTX-M-9 group (CTX-M-14). The presence of these genes in bacteria isolated from pets is an important fact that constitutes a public health concern.
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PMID:Extended-spectrum beta-lactamases belonging to CTX-M group produced by Escherichia coli strains isolated from companion animals treated with enrofloxacin. 1816 82

The beta-lactamase (BLA) genes, the genes for aminoglycosides-modifying enzymes (AMEs), disinfectant-sulfanilamide resistance (qacEDelta1-sul1) genes, class 1 integrase (intl1) gene, and the qnr gene associated with plasmid-mediated quinolone resistance were analyzed using PCR and verified by DNA sequencing for 31 clinical isolates of multidrug-resistant Acinetobacter baumannii (MDRAB). The organism typing was performed by pulsed-field gel electrophoresis (PFGE). The positive rate of ADC, TEM, PER, and DHA of BLA genes were 100%, 61.3%, 19.4%, and 3.2%, respectively; however, the genes of SHV, OXA-23 group, OXA-24 group, GES, VIM, IMP, and qnr gene were negative. The positive rate of the genes of AMEs for aac (3)-I, aac (6')-I, ant (3")-I, ant (2")-I, aac (3)-II, and aac (6')-II were 67.7%, 45.2%, 29.0%, 22.6%, 12.9%, and 3.2%, respectively. The positive rate of qacEDelta1-sul1 and intl1 were 80.6% and 58.1%, respectively. Six different PFGE clones were found, of which two dominated. The findings show that clinical isolates of MDRAB harbor various kinds of resistance genes.
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PMID:Detection of drug resistance-associated genes of multidrug-resistant Acinetobacter baumannii. 1848 41

We propose a simple and rapid method to discriminate SHV-type extended spectrum beta-lactamase (ESBL) genes in P. aeruginosa based on PCR techniques (PCR-RFLP and RSI-PCR). We studied 22 producing ESBL P. aeruginosa strains isolated from seven immunocompromised patients (19 isolates) and from environmental swabs (three isolates) at the Bone Marrow Transplantation Center of Tunis. Screening PCR with primer pairs designed to detect gene encoding TEM, SHV, OXA group I, OXA group II, OXA-18 and PER-1 ESBL was positive for bla(OXA18) and bla(SHV) genes in all isolates. Pulsed field gel electrophoresis using SpeI endonuclease defined five genotypic groups. For at least one isolate corresponding to each genotype observed, restriction of PCR products by DdeI and BsrI revealed the same restriction pattern that the bla(SHV-1) negative control; in the same way, RSI-PCR products digestion by NruI, thus excluding 35, 238 and 240 mutations characterizing reported ESBL in P. aeruginosa (SHV-2a, SHV5 et SHV12), and suggesting that studied bla(SHV) genes were not ESBL ones. Genomic DNA hybridization by southern blot with probe consisting in bla(SHV-1) gene was positive in these isolates. Sequencing the full-length open reading frame revealed nucleotide sequence of the bla(SHV-1). PCR-RFLP and RSI-PCR results were then confirmed. This approach is effective for screening P. aeruginosa for ESBL genes carriage in epidemiological studies and for detecting new variants.
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PMID:[Identification of SHV-type extended spectrum beta-lactamase genes in Pseudomonas aeruginosa by PCR-restriction fragment length polymorphism and insertion site restriction-PCR]. 1883 31

LK-157 is a novel tricyclic carbapenem with potent activity against class A and class C beta-lactamases. When tested against the purified TEM-1 and SHV-1 enzymes, LK-157 exhibited 50% inhibitory concentrations (IC(50)s) in the ranges of the clavulanic acid and tazobactam IC(50)s (55 nM and 151 nM, respectively). Moreover, LK-157 significantly inhibited AmpC beta-lactamase (IC(50), 62 nM), as LK-157 was >2,000-fold more potent than clavulanic acid and approximately 28-fold more active than tazobactam. The in vitro activities of LK-157 in combination with amoxicillin, piperacillin, ceftazidime, cefotaxime, ceftriaxone, cefepime, cefpirome, and aztreonam against an array of Ambler class A (TEM-, SHV-, CTX-M-, KPC-, PER-, BRO-, and PC-type)- and class C-producing bacterial strains derived from clinical settings were evaluated in synergism experiments and compared with those of clavulanic acid, tazobactam, and sulbactam. In vitro MICs against ESBL-producing strains (except CTX-M-containing strains) were reduced 2- to >256-fold, and those against AmpC-producing strains were reduced even up to >32-fold. The lowest MICs (< or =0.025 to 1.6 microg/ml) were observed for the combination of cefepime and cefpirome with a constant LK-157 concentration of 4 microg/ml, thus raising an interest for further development. LK-157 proved to be a potent beta-lactamase inhibitor, combining activity against class A and class C beta-lactamases, which is an absolute necessity for use in the clinical setting due to the worldwide increasing prevalence of bacterial strains resistant to beta-lactam antibiotics.
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PMID:In vitro activity of LK-157, a novel tricyclic carbapenem as broad-spectrum {beta}-lactamase inhibitor. 1907 67


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