First identification of an SHV-12 extended-spectrum β-lactamase in Klebsiella pneumoniae isolated in Italy

Abstract

A clinical isolate of Klebsiella pneumoniae highly resistant to third- and fourth-generation cephalosporins, cephamycins and aminoglycosides, was isolated in 1991 from urine. Analysis of a crude extract showed the presence of three beta-lactamases with isoelectric points of 6.6, 7.5 and 8.2. The enzyme with pI 8.2 was transferred by conjugation into Escherichia coli K-12 J53 and was responsible for the resistance to third-generation cephalosporins and monobactams, but not to other antibiotics. Kinetic studies of partially purified beta-lactamase from the transconjugant strain confirmed that the enzyme was able to hydrolyse ceftazidime, cefotaxime and aztreonam but not cephamycins. Analysis of the transconjugant showed the presence of two small non-conjugative plasmids of 14 and 6 kb. A polymerase chain reaction was performed using primers specific for the bla(SHV) gene and a fragment of the expected size (about 961 bp) was obtained with both the K. pneumoniae clinical isolate and the transconjugant. Nucleotide sequence analysis of the fragment showed that it encoded the enzyme SHV-12, derived from SHV-5 (with Gln-35 to Leu). This is the first report of an SHV-12-like enzyme isolated in Italy.

Multidrug and Broad-Spectrum Cephalosporin Resistance among Salmonella enterica Serotype Enteritidis Clinical Isolates in Southern Italy

“…The hypothesis of nosocomial acquisition would be in agreement with previous studies indicating that nontyphoid salmonellae producing TEM or SHV ESBLs may have exchanged bla genes with other enterobacteria frequently encountered in hospitals (21,22). Besides, SHV-12-encoding plasmids have been previously encountered in Klebsiella pneumoniae isolates from hospitals throughout Italy (11,15). A similar hypothesis could also be formulated for isolate S76, which produced a class C ␤-lactamase, since enterobacterial clinical isolates with plasmid-mediated cephalosporinases have been repeatedly reported in European countries and the United States (16,23).…”

Molecular Characterization of Extended-Spectrum β-Lactamases Produced by Nosocomial Isolates of Enterobacteriaceae from an Italian Nationwide Survey

“…WEP67, 2000). However, the nature and prevalence of the enzymes responsible for this phenomenon have not been investigated, except for a few cases in which the enzymes were characterized at the molecular level (11,14,16). In this report, we describe the first large-scale characterization of TEM-and SHV-type ESBL variants produced by Enterobacteriaceae circulating in Italian hospitals.…”

“…More recently, the problem has emerged worldwide (19,24). Several different enzyme variants have been identified (K. Bush and G. A. Jacoby, 1999, http://www.lahey .org/studies/webt.htm), and notable epidemiological differences have been reported in different geographic areas (11,17,18,19,20,24,25). In Italy, although ESBL-producing clinical isolates have been occasionally reported (6,11,16,21) and resistance to expanded-spectrum ␤-lactams is increasing (16) In this study, the nature and diversity of TEM and SHV enzymes was investigated in a large number of ESBL-producing isolates collected during the above-mentioned survey.…”

Molecular Epidemiology of Extended-Spectrum β-Lactamases from Klebsiella pneumoniae Strains Isolated in Zagreb, Croatia

“…An SHV variant described recently in Switzerland, SHV-12 [10], is also present in Zagreb; however, it was only isolated at Sestre Milosrdnice Hospital (Table 1). Although SHV-12 previously seemed rare, reports from the Far East [11] and Italy [12] have recently appeared.…”