Resistance mechanisms of multiresistant serotype 012 Pseudomonas aeruginosa isolated in Europe

Abstract

Serotype 012 Pseudomonas aeruginosa resistant to gentamicin (MIC greater than 4 mg/l) and carbenicillin (MIC greater than 128 mg/l) occur widely in Europe and are homogeneous in their phenotypic and genetic properties. It has been suggested that a single multiresistant strain of this serotype has become widespread. This study examined the resistance mechanisms present in multiresistant serotype 012 P. aeruginosa isolates from Austria, Belgium, France, Greece, Italy, Holland, West Germany and the UK. Disseminated isolates produced a PSE-1 type beta-lactamase, correlating with their resistance to the known substrates of this enzyme (carbenicillin, azlocillin and cefsulodin). These isolates also reacted with gene probes for the aminoglycoside modifying enzymes AAC(6')I and ANT(3'). The probe for AAC(6')I is known to cross-react with the gene for AAC(6')II. The fact that the organisms were resistant to netilmicin, gentamicin, sisomicin and tobramycin, but less so to amikacin, suggested that the latter enzyme was produced rather than AAC(6')I. PSE-1 beta-lactamase and the gene for AAC(6')I/AAC(6')II were absent from the International Antigenic Typing Scheme 012 reference strain, which was sensitive to beta-lactams and aminoglycosides, and also from a multiresistant serotype 012 strain isolated at a London burns unit in 1987. These organisms have been shown previously to be distinct from the disseminated multiresistant strain in their phenotypic properties. Two 012 isolates appeared to have additional resistance determinants to amikacin and isepamicin.

Primary mechanisms mediating aminoglycoside resistance in the multidrug-resistant Pseudomonas aeruginosa clinical isolate PA7

“…O12 is a predominant serotype associated with multidrug resistance to a number of antibiotic classes, including aminoglycosides and b-lactams, although it represents a minor serotype in the environment (Legakis et al, 1982;Pitt et al, 1990;Bert et al, 1996;Samuelsen et al, 2010). The presence of the oprA gene in P. aeruginosa might be more advantageous for its survival in the presence of aminoglycosides, other antimicrobials such as b-lactams (e.g.…”

Emergence of Salmonella epidemics: The problems related to Salmonella enterica serotyp Enteritidis and multiple antibiotic resistance in other major serotypes

“…Indeed, tet(G) also occurs in bacteria of this genus [130], and similarly floR is closely related to the P. aeruginosa chloramphenicol-resistance gene cmlA [6,24]. Moreover, the bla PSE-1 -encoded β-lactamase is a common feature of hospital P. aeruginosa isolates [120]. Thus, the hypothesis that S. Typhimurium DT104 acquired resistance genes horizontally from nosocomial pseudomonads might also be worth considering.…”

Outbreak of Carbapenem-Resistant Pseudomonas aeruginosa Producing VIM-8, a Novel Metallo-β-Lactamase, in a Tertiary Care Center in Cali, Colombia

“…In the case of P. aeruginosa, the most frequent mechanism of resistance is loss of the porin OprD (24), but carbapenem-hydrolyzing ␤-lactamases are increasingly reported. They spread first in Japan and Korea and more recently in Europe (4,26,27) and the Americas (7,11). Large outbreaks by MBL-producing P. aeruginosa strains have been described in hospitals in Italy, Greece, and Korea (4,14,16,18,20,29), as well as in Latin America, notably, including one caused by a P. aeruginosa strain with an SPM-1 ␤-lactamase in Brazil (7).…”

“…Outbreaks of VIM ␤-lactamase-producing, serotype O12 P. aeruginosa strains have occurred in Italy (5), Greece (20,32), and Korea (18). Fifteen years ago, O12 was the major serotype of P. aeruginosa strains hosting the PSE-1 ␤-lactamase, at least in Europe (26). It may be that serotype O12 strains, which form a tight cluster in terms of DNA relatedness (21,25), are particularly adept at acquiring or hosting the integrons that encode the IMP, VIM, and PSE enzymes, but this hypothesis is speculative.…”