Emergence of class 1 integron-associated GES-5 and GES-5-like extended-spectrum β-lactamases in clinical isolates of Pseudomonas aeruginosa in South Africa

Abstract Background Treatment of serious infections due to multidrug-resistant (MDR) Pseudomonas aeruginosa remains a challenge, despite the introduction of novel therapeutics. In this study, we report 2 extensively drug-resistant clinical isolates of sequence type (ST) 309 P aeruginosa resistant to all β-lactams, including the novel combinations ceftolozane/tazobactam, ceftazidime/avibactam, and meropenem/vaborbactam. Methods Isolates were sequenced using both short-read (Illumina) and long-read technology to identify resistance determinants, polymorphisms (compared with P aeruginosa PAO1), and reconstruct a phylogenetic tree. A pair of β-lactamases, Guiana extended spectrum β-lactamase (GES)-19 and GES-26, were cloned and expressed in a laboratory strain of Escherichia coli to examine their relative impact on resistance. Using cell lysates from E coli expressing the GES genes individually and in tandem, we determined relative rates of hydrolysis for nitrocefin and ceftazidime. Results Two ST309 P aeruginosa clinical isolates were found to harbor the extended spectrum β-lactamases GES-19 and GES-26 clustered in tandem on a chromosomal class 1 integron. The presence of both enzymes in E coli was associated with significantly elevated minimum inhibitory concentrations to aztreonam, cefepime, meropenem, ceftazidime/avibactam, and ceftolozane/tazobactam, compared with those expressed individually. The combination of ceftazidime/avibactam plus aztreonam was active in vitro and used to achieve cure in one patient. Phylogenetic analysis revealed ST309 P aeruginosa are closely related to MDR strains from Mexico also carrying tandem GES. Conclusions The presence of tandem GES-19 and GES-26 is associated with resistance to all β-lactams, including ceftolozane/tazobactam. Phylogenetic analysis suggests that ST309 P aeruginosa may be an emerging threat in the United States.

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In99, an In100-related integron, its occurrence and prevalence in clinical Pseudomonas aeruginosa strains from a central region of Portugal

Epidemiology and Infection ◽

10.1017/s095026880600700x ◽

2006 ◽

Vol 135 (3) ◽

pp. 502-504 ◽

Cited By ~ 3

Author(s):

T. CAETANO ◽

S. FERREIRA ◽

A. P. MONDEGO ◽

A. CORREIA ◽

S. MENDO

Keyword(s):

Pseudomonas Aeruginosa ◽

Resistance Genes ◽

Central Region ◽

Clinical Isolates ◽

Aminoglycoside Resistance ◽

Class 1 Integron ◽

Class 1 ◽

Aminoglycoside Resistance Genes

In99, a possible ancestor of In100, is a class 1 integron associated with carbenicillinase (blaPSE) and aminoglycoside resistance genes [aac(6′)-Ib and aadA2]. In99 was present in 8 of 81 clinical isolates of Pseudomonas aeruginosa from unrelated patients collected in different years. The strains fell into two clonal groups and exhibited resistance to β-lactams and aminoglycosides.

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Chromosome-Encoded AmpC and CTX-M Extended-Spectrum β-Lactamases in Clinical Isolates ofProteus mirabilisfrom Korea

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01835-09 ◽

2011 ◽

Vol 55 (4) ◽

pp. 1414-1419 ◽

Cited By ~ 36

Author(s):

Wonkeun Song ◽

Juwon Kim ◽

Il Kwon Bae ◽

Seok Hoon Jeong ◽

Young Hee Seo ◽

...

Keyword(s):

Chromosomal Location ◽

Clinical Isolates ◽

Class 1 Integron ◽

Extended Spectrum ◽

Hospital Environments ◽

Class 1 ◽

Genes Encoding ◽

Unusual Phenomenon ◽

M 12 ◽

Lactamase Gene

ABSTRACTAmong 222Proteus mirabilisclinical isolates collected from 17 hospitals in Korea in 2008, 28 (12.6%) and 8 (3.6%) isolates exhibited extended-spectrum β-lactamase (ESBL) and AmpC phenotypes, respectively. The most common type of ESBL gene identified by PCR and sequencing experiments wasblaCTX-M-14a(n= 12). TheblaCTX-M-90(n= 4),blaCTX-M-15(n= 3),blaCTX-M-12(n= 3),blaCTX-M-2(n= 2),blaCTX-M-14b(n= 1),blaTEM-52(n= 5), andblaSHV-12(n= 1) genes were also detected. Eight isolates carried an AmpC β-lactamase gene, such asblaCMY-2(n= 6) orblaDHA-1(n= 2). Allblagenes encoding CTX-M-1- and CTX-M-9-type enzymes and allblaCMY-2genes were preceded by ISEcp1-like elements. TheblaCTX-M-2gene found in two isolates was located on a complex class 1 integron. TheblaDHA-1gene was preceded by a transcriptional regulator gene and was followed by phage shock protein genes. TheblaCTX-Mgenes were located on the chromosome in 21 isolates. A plasmid location for theblaCTX-Mgene was found in only four isolates: theblaCTX-M-14agene was located on ∼150-kbp IncA/C plasmids in three isolates and on a ∼50-kbp IncN plasmid in one isolate. TheblaTEM-52gene was located on ∼50-kbp IncN plasmids in all five isolates. The AmpC β-lactamase genes were located on the chromosome in seven of eight isolates; one isolate carried theblaCMY-2gene on a ∼150-kbp IncA/C plasmid. Our results show that a chromosomal location of CTX-M ESBL and AmpC β-lactamase genes inP. mirabilisis no longer an unusual phenomenon in hospital environments.

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Metallo-β-Lactamase Gene blaIMP-15 in a Class 1 Integron, In95, from Pseudomonas aeruginosa Clinical Isolates from a Hospital in Mexico

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00679-07 ◽

2008 ◽

Vol 52 (8) ◽

pp. 2943-2946 ◽

Cited By ~ 38

Author(s):

U. Garza-Ramos ◽

R. Morfin-Otero ◽

H. S. Sader ◽

R. N. Jones ◽

E. Hernández ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Tertiary Care Hospital ◽

Tertiary Care ◽

Gene Cassette ◽

Clinical Isolates ◽

Care Hospital ◽

Class 1 Integron ◽

Carbapenem Resistant ◽

Class 1 ◽

Lactamase Gene

ABSTRACT During 2003, 40 carbapenem-resistant Pseudomonas aeruginosa clinical isolates collected in a Mexican tertiary-care hospital were screened for metallo-β-lactamase production. Thirteen isolates produced IMP-15, and 12 had a single pulsed-field gel electrophoresis pattern. The bla IMP-15 gene cassette was inserted in a plasmid-borne integron with a unique array of gene cassettes and was named In95.

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Molecular Characterization of a Novel Class 1 Integron Containing blaGES-1 and a Fused Product of aac(3)-Ib/aac(6")-Ib" Gene Cassettes in Pseudomonas aeruginosa

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.46.3.638-645.2002 ◽

2002 ◽

Vol 46 (3) ◽

pp. 638-645 ◽

Cited By ~ 92

Author(s):

Véronique Dubois ◽

Laurent Poirel ◽

Caroline Marie ◽

Corinne Arpin ◽

Patrice Nordmann ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Diffusion Method ◽

Fusion Product ◽

Resistance Pattern ◽

Clinical Strain ◽

Homologous Sequence ◽

Class 1 Integron ◽

Gene Cassettes ◽

Extended Spectrum ◽

Class 1

ABSTRACT As seen by the disk diffusion method, the clinical strain of Pseudomonas aeruginosa Pa695, resistant to all extended-spectrum cephalosporins and aminoglycosides, exhibited an unusual synergistic effect between ceftazidime and imipenem. This isolate produced an extended-spectrum β-lactamase (ESBL) with a pI of 5.8 that appeared to be chromosomally encoded. Cloning experiments revealed that this ESBL was encoded by bla GES-1, previously described in an integron from Klebsiella pneumoniae. In P. aeruginosa Pa695, a higher level of resistance to ceftazidime than to ticarcillin was observed, and no synergy between the β-lactamase inhibitors and extended-spectrum cephalosporins was detected, in contrast to the resistance pattern observed in K. pneumoniae. Further sequence analysis demonstrated that the bla GES-1 gene cassette was located in a class 1 integron, which contained another sequence corresponding to the fused aac(3)-Ib and aac(6")-Ib" gene cassettes. The fusion product was functional, as was the product of each gene cloned separately: AAC(3)-I, despite the deletion of the four last amino acids, and AAC(6"), which carried three amino acid changes compared with the most homologous sequence. The AAC(3)-I protein conferred an expected gentamicin and fortimicin resistance, and the AAC(6"), despite the Leu-119→Ser substitution, yielded resistance to kanamycin, tobramycin, and dibekacin, but slightly affected netilmicin and amikacin, and had no apparent effect on gentamicin. The fusion product conveyed a large profile of resistance, combining the AAC(6") activity with a higher level of gentamicin resistance without accompanying fortimicin resistance.

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