Healthcare-associated carbapenem-resistant OXA-72-producing Acinetobacter baumannii of the clonal complex CC79 colonizing migratory and captive aquatic birds in a Brazilian Zoo.

Carbapenem resistance in Acinetobacter baumannii is a public health issue globally, mainly due to the production of carbapenem hydrolyzing class D ß-lactamases (CHDLs). In Brazil, OXA-23 and OXA-143 CHDLs have been prevalent in A. baumannii from clinical settings, with some OXA-23 reports in the environmental samples, whereas OXA-72 has begun to be increasingly reported. This study aims to perform the genomic and microbiological characterization of carbapenem-resistant A. baumannii isolates recovered from migratory birds and captive birds inhabiting a lake within a Brazilian Zoo. Four hundred and eighty-one gram-negative bacilli were recovered from choanal and cloacal swabs obtained from 50 migratory birds and 37 captive birds present at the zoo's lake between July and August of 2012. Among all GNB, nine OXA-72-producing A. baumannii were detected from the microbiota of four migratory and five captive aquatic birds. The OXA-72-producing A. baumannii isolates were submitted to antimicrobial susceptibility test and PFGE, exhibiting a multidrug-resistant profile and clonal relatedness with OXA-72-positive human isolates circulating for eighteen years in a hospital setting. MLST, plasmid analysis and whole-genome sequencing revealed which all carbapenem-resistant A. baumannii from bird and human hosts belonged to clonal complex 79, and harboured a small plasmid (⁓16.6-kb in size), named pAC1-BRL, which carried blaOXA-72 gene, macrolide resistance genes msrE and mphE, and the toxin-antitoxin system AbkAB. To determine the impact of pAC1-BRL acquisition in the the capacity of a microorganism to survive in a competitive environment (in the following called fitness), the laboratory strain A. baumannii ATCC 19606 was used in the fitness experiments and suggested an increase of its relative fitness after the pAC1-BRL acquisition. In summary, the detection of OXA-72-producing A. baumannii strains belonging to CC79 in aquatic birds is a piece of epidemiological evidence demonstrating that dissemination of high-risk bacteria is extending beyond the hospital.

Genetic Characterization of Plasmid-Borne blaOXA-58 in Distinct Acinetobacter Species.

We characterize by whole-plasmid-sequence (WPS) two-plasmid-borne blaOXA-58 obtained from Acinetobacter seifertii (Asp-1069) and A. baumannii (Acb-45063) clinical strains recovered 17 years apart from distinct Brazilian regions. Multilocus sequence type (MLST) analysis showed that the Asp-1069 and Acb-45063 strains belong to ST551 and ST15/CC15, respectively. WPS analysis demonstrated that blaOXA-58 was located in two distinct plasmids named pAs1069_a (24,672 bp/44 open reading frames [ORFs]) and pAb45063_b (19,808 bp/24 ORFs), which belong to the GR8/GR23 (repAci23) and GR4 (repAci4) incompatibility groups, respectively. The genetic environments surrounding blaOXA-58 revealed that it was flanked by two intact ISAba3 copies on pAb45063_b, which differed from pAs1069_a. In the latter, the upstream ISAba3 copy was truncated by insertion of ISAba825 element. Although Re27-specific recombination sites were found adjacent to ISAba3-blaOXA-58-ISAba3 arrangement on pAb45063_b, such structures were absent on pAs1069_a. The conserved ISAba125-araC1-lysE arrangement was disrupted by TnaphA6 harboring the aminoglycosides resistance gene aphA6 on pAs1069_a, while an IS26-blaTEM-1-aac(3)-IIa-IS26 genetic structure was found upstream from ISAba3-blaOXA-58-ISAba3 on pAb45063_b. Other two plasmids, pAb45063_a (183,767 bp/209 ORFs) and pAs1069_b (13,129 bp/14 ORFs), were also found in the OXA-58-producing Acinetobacter species strains, harboring the strA and strB genes and the sul2 gene, which confer resistance to streptomycin and sulfonamides, respectively. The plasmid-mediated virulence factors corresponding to genes tonB, spl, glmM, ppa, sulP, and map were found in both strains, as well distinct toxin-antitoxin system-encoding genes stbD and relE (pAs1069_a), brnT and brnA (pAb45063_b), and xreE (pAb45063_a). Although infrequently reported in Brazil, plasmid-borne blaOXA-58 showed a complex and diverse genetic backbone that confers stability in different Acinetobacter species that have been isolated from nosocomial settings over time.IMPORTANCE Although the blaOXA-58 gene has been infrequently described in Brazil, contrasting with other bordering South American countries, we verified the maintenance of this resistance determinant over time among carbapenem-resistant Acinetobacter species isolates, not only in nosocomial settings but also in the environment. In addition, to the best of our knowledge, this is the first study to have used WPS analysis to evaluate the genetic surroundings of blaOXA-58 in Brazil. Moreover, the A. seifertii and A. baumannii clinical strains evaluated in this study were recovered 17 years apart in hospitals located in distinct Brazilian geographic regions.

SPM-1-producing Pseudomonas aeruginosa ST277 clone recovered from microbiota of migratory birds.

The production of São Paulo metallo-ß-lactamase (SPM-1) is the most common carbapenem resistance mechanism detected among multidrug-resistant Pseudomonas aeruginosa clinical isolates in Brazil. Dissemination of SPM-1-producing P. aeruginosa has been restricted to the nosocomial settings, with sporadic reports of environmental isolates due to contamination by hospital sewage. Herein, we described the detection and molecular characterization of SPM-1-producing P. aeruginosa recovered from the microbiota of migratory birds in Brazil. Three hundred gram-negative bacilli were recovered from cloacal and choanal swabs of Dendrocygna viduata during a surveillance study for detection of carbapenem-resistant isolates. All isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. MICs were determined by agar dilution, except for polymyxin B. Antibiotic resistance genes were detected by polymerase chain reaction (PCR) followed by DNA sequencing. Transcriptional levels of oprD and efflux system encoding genes were also carried out by quantitative real-time PCR. Nine imipenem-resistant P. aeruginosa isolates were recovered with 7 of them carrying blaSPM-1. Additional resistance genes (rmtD-1, blaOXA-56,aacA4, and aac(6')-Ib-cr) were also detected in all 9 isolates. The SPM-1-producing isolates showed high MICs for all ß-lactams, fluoroquinolones, and aminoglycosides, being susceptible only to polymyxin B. Interestingly, all isolates showed the same PFGE pattern and belonged to ST277. Overexpression of MexXY-OprM and MexAB-OprM was observed in those isolates that did not harbor blaSPM-1. Our results suggest that migratory birds might have played a role in the dissemination of SPM-1-producing P. aeruginosa within the Brazilian territory.