Genomics and Antimicrobial Susceptibility of Clinical Pseudomonas aeruginosa Isolates from Hospitals in Brazil.

Pseudomonas aeruginosa, an opportunistic pathogen causing infections in immunocompromised patients, usually shows pronounced antimicrobial resistance. In recent years, the frequency of carbapenemases in P. aeruginosa has decreased, which allows use of new beta-lactams/combinations in antimicrobial therapy. Therefore, the in vitro evaluation of these drugs in contemporary isolates is warranted. We evaluated the antimicrobial susceptibility and genomic aspects of 119 clinical P. aeruginosa isolates from 24 different hospitals in Brazil in 2021-2022. Identification was performed via MALDI-TOF-MS, and antimicrobial susceptibility was identified through broth microdilution, gradient tests, or disk diffusion. Whole-genome sequencing was carried out using NextSeq equipment. The most active drug was cefiderocol (100%), followed by ceftazidime-avibactam (94.1%), ceftolozane-tazobactam (92.4%), and imipenem-relebactam (81.5%). Imipenem susceptibility was detected in 59 isolates (49.6%), and the most active aminoglycoside was tobramycin, to which 99 (83.2%) isolates were susceptible. Seventy-one different sequence types (STs) were detected, including twelve new STs described herein. The acquired resistance genes blaCTX-M-2 and blaKPC-2 were identified in ten (8.4%) and two (1.7%) isolates, respectively. Several virulence genes (exoSTUY, toxA, aprA, lasA/B, plcH) were also identified. We found that new antimicrobials are effective against the diverse P. aeruginosa population that has been circulating in Brazilian hospitals in recent years.

Co-production of Classes A and B Carbapenemases BKC-1 and VIM-2 in a Clinical Pseudomonas Putida Group Isolate from Brazil.

Emergence of resistance to classical antimicrobial agents is a public health issue, especially in countries with high antimicrobial consumption rates. Carbapenems have been employed as first-choice option for empirical treatment complicated infections. However, in the last decades, frequency of carbapenemase-producing Gram-negative bacteria has rising, demanding the use of alternative antimicrobial agents. By sequencing the entire genomes with short and long reads technologies, we report the isolation and genomic characterization of a carbapenem-resistant Pseudomonas clinical isolate. The identification based on average nucleotide identity indicates a putative new species into the Pseudomonas putida Group, which carries both the blaBKC-1 and blaVIM-2 carbapenemase genes. The blaBKC-1 was found to be on a transferable IncQ plasmid backbone, whereas blaVIM-2 was found in a new integron, In2126 (intl1∆-blaVIM-2-aacA7-blaVIM-2∆-aacA27-3'CS), described in this study. Our findings indicate that co-occurrence of classes A and B carbapenemase enzymes underscores the evolving emergence of more complex antimicrobial resistance in opportunistic pathogens.

Prevalence and antimicrobial susceptibility profile of Enterococcus spp isolated from frozen chicken carcasses

Prevalence and antimicrobial susceptibility of Enterococcus spp. were evaluated in 360 frozen unse asoned chicken carcasses samples collected from September 2004 to June 2006 from the retail stores in São Paulo State, Brazil. Enterococcus spp. was isolated from all analyzed samples, and 1,332 strains were identified from them. Among the ten identified species, the predominance of E. faecalis, E. gallinarum, E.casseliflavus and E. faecium was occurred. All of the Enterococci strains showed some degree of resistanceto the nine antimicrobials utilized in the study. The percentages of antimicrobial resistance were: 89.2% for tetracycline, 91.4% for quinupristin-dalfopristin, 83.5% for erythromycin, 65% for ciprofloxacin, 55.4% for chloramphenicol, 6.5% for linezolid, 2.3% for vancomycin, 2.3% for teicoplanin and 0.2% for ampicillin. The occurrence of the high level resistance to amyno glicosides (HLR-A) was detected in 57.4% of the isolates. E. faecalis and E. faecium species, which are considered as important agents in nosocomial infections, showed resistance to eight and seven antibiotics, respectively.