![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
Previous Article | Next Article 
Antimicrobial Agents and Chemotherapy, October 2001, p. 2856-2861, Vol. 45, No. 10
Department of
Pharmacology1 and Department of
Microbiology,2 Municipal Institute of
Medical Investigation, 08003 Barcelona, and Laboratori de
Rèferencia de Catalunya (Microbiology), Autovia de
Castelldefels, 08907 L'Hospitalet de Llobregrat,
Barcelona,3 Spain
Received 1 February 2001/Returned for modification 12 May
2001/Accepted 10 July 2001
The nature of the SHV-1
0066-4804/01/$04.00+0 DOI: 10.1128/AAC.45.10.2856-2861.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
SHV-1
-Lactamase Is Mainly a Chromosomally
Encoded Species-Specific Enzyme in Klebsiella
pneumoniae
-lactamase gene was analyzed in
97 epidemiologically unrelated Klebsiella
pneumoniae strains isolated from clinical samples.
-Lactamase bands that focused at a pI of 7.6 (SHV-1-type) in 74 strains, at a pI of 7.1 (LEN-1-type) in 13 strains, and at a pI of 5.4 (TEM-1-type) in 10 strains were detected by analytical isoelectric
focusing (IEF). Among the 74 SHV-1-producing strains, 40 had, in
addition to the pI 7.6 band, an additional band on IEF: 20 had a
band with a pI of 7.1 and 20 had a band with a pI of 5.4. Most
of the 74 SHV-1-producing strains (76.7%) carried plasmids. Transfer
of -lactam resistance by conjugation was possible in only 9.3% of
the strains tested. SHV-1 gene-specific PCR-restriction fragment length
polymorphism (PCR-RFLP) analysis of the chromosomal DNA was positive
for 93 of the 97 strains and negative for only 4 of the 10 samples with K. pneumoniae TEM-1 producers. In an attempt to
approximate the location of the SHV gene locus by endonuclease
restriction analysis, RFLP analysis with Southern blotting of
chromosomal DNA with a labeled SHV-1 fragment as a probe was used to
study the 97 strains. A trial with EcoRI showed at least
one positive hybridization band for 96 strains; two bands were detected
for 8 strains. The hybridization was negative for only one TEM-1
-lactamase-producing strain. DNA sequence analysis showed no
differences in promoter regions or extra stop-triplet sequences;
only point mutations determined different allelic variants. The
novel SHV-type variants are designated SHV-32 and SHV-33. As a result
of the RFLP and sequencing analyses, it can be postulated that the loci
for SHV-1 and LEN-1 genes are arranged in tandem. Our results
strongly support the hypothesis that the ancestor of the SHV-1
-lactamase originated from the K. pneumoniae chromosome.
*
Corresponding author. Mailing address: CID-CSIC,
C/Jordi Girona, 18-26, 08034 Barcelona, Spain. Phone: 34-93-400 61 00. Fax: 34-93-204 59 04. E-mail: mglqob{at}cid.csic.es.
Through this study, we wish to posthumously pay our last respects
to Clara Roy, who was the head of the Microbiology Department for many years.
This article has been cited by other articles:
| Clin. Vaccine Immunol. | Clin. Microbiol. Rev. |
|---|---|
| J. Clin. Microbiol. | ALL ASM JOURNALS |
