Emergence of SHV-2a Extended-Spectrum β-Lactamases in Clinical Isolates ofPseudomonas aeruginosain a University Hospital in Tunisia

Abstract

Extended-spectrum beta-lactamases (ESBLs) in Pseudomonas aeruginosa are increasingly reported worldwide. In our study, a total of 70 clinical isolates of multidrug-resistant P. aeruginosa were studied. Isoelectric focusing electrophoresis, PCR, and PCR product sequencing were designed to characterize the contained ESBLs. The Double Disk Synergy Test in Cloxacillin (250 microg/ml)-containing Mueller-Hinton agar plates with a 20 mm distance between disks was the most reliable ESBL-screening method. Seven out of 70 multidrug-resistant P. aeruginosa clinical isolates were positive for ESBL and have the bla(SHV-2a) ESBL gene. The bla(SHV-2a)-positive isolates were clonally related according to Enterobacterial Repetetive Intergenic Consensus-PCR (ERIC-PCR) results. The bla(SHV-2a) gene was found to be chromosomally located, and the flanking IS26 sequence in the immediate upstream region of the bla(SHV-2a) gene was detected in all SHV-2a-producing isolates. This is the first report of SHV-2a-producing P. aeruginosa isolates from Tunisia.

Emerging broad-spectrum resistance in Pseudomonas aeruginosa and Acinetobacter baumannii : Mechanisms and epidemiology

“…The SHV-type ESBLs have been identified in very rare isolates of P. aeruginosa, being SHV-2a in France and Tunisia [67,68] and SHV-12 in Thailand [69] and Japan [70] (Table 1). A nosocomial outbreak of SHV-5-producing P. aeruginosa was also described in Greece [71].…”

Molecular Detection of blaVEB-1 Beta-Lactamase Encoding Gene Among Extended Spectrum B-Lactamase Positive Wound Isolates of Pseudomonas aeruginosa

“…These six types of ESBLs at the genetic level have a low similarity, but they are identical regarding hydrolysis profiles (6). The ESBL enzymes have been demonstrated to be the derivatives of TEM-and SHV-lactamases, with minor genetic mutation in the active site (7). These enzymes have shown resistance to extended spectrum cephalosporins.…”

Acquisition of a Transposon Encoding Extended-Spectrum β-Lactamase SHV-12 by Pseudomonas aeruginosa Isolates during the Clinical Course of a Burn Patient

“…In contrast, there are a few reports describing the isolation of TEM-or SHV-type ESBLs in Pseudomonas aeruginosa (19). In the Enterobacteriaceae, genes encoding SHV-type enzymes usually are located on plasmids (8), whereas they are primarily chromosomally encoded in P. aeruginosa (2,10,11,15). We consider that the difference is one of the reasons that P. aeruginosa strains harboring genes for SHV-type enzymes are very rare.…”

“…The IS26 insertion sequence is widely distributed among the Enterobacteriaceae plasmids; on the other hand, only two studies have detected bla SHV associated with IS26 in P. aeruginosa (10,11). However, these studies did not examine the regions around the IS26 elements.…”

“…Several studies have suggested that P. aeruginosa represents a hidden reservoir for ESBLs (10,11). The present study indicates that P. aeruginosa and the Enterobacteriaceae use dif- A burn patient (27-year-old female) suffered from a total burn surface area of 83% and transferred to Sapporo Medical University Hospital on the fourth clinical day.…”