RESUMO
OBJECTIVES: The Enterobacter cloacae complex (ECC) are causatives of hospital-acquired infections. The antimicrobial resistance (AMR) and virulence profiling of ECC promotes our knowledge for their elimination in clinical settings. METHODS: We assembled the whole genome of four clinical carbapenem-resistant ECCs and characterized their AMR and virulence profiles using whole genome sequencing. RESULTS: The chromosomes length scaled from minimum 3 949 952 bp (for P2) to maximum 4 976 575 bp (for P3). Strains P1 and P2 belonged to sequence type (ST)182. P3 and P4 belonged to ST477 and ST134, respectively. The blaCTX-M-15 gene was detected in P1 plasmid. P1 and P4 harboured the blaTEM-1 and blaOXA-1 genes. blaNDM-1 was found in P1, P3, and P4. No blaOXA-48, blaKPC, blaVIM, or blaIMP were identified. The plasmids were nontransferable and had IncFIB, IncFII, Col, and IncC incompatibility (Inc) groups . Class 1 integron was detected in all strains. Virulence genes related to biofilms, adhesins, siderophores (aerobactin, enterobactin, and salmochelin), intrinsic antimicrobial efflux pumps, secretory systems type I to VI, environmental and antibiotic stress response , outer membrane proteins, and heavy metal (copper, tellurite, arsenic, and zinc) resistance were found. The number of positive virulence factors was higher for P1 compared with other strains. CONCLUSION: The accumulation of AMR genes in Enterobacter spp. and their high endurance in hostile environments is a serious health problem. More genomic investigations are required to determine their AMR and virulence genetic reservoirs at the global level.
Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos , Enterobacter cloacae , Antibacterianos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Carbapenêmicos/farmacologia , Enterobacter cloacae/genética , Virulência/genética , beta-LactamasesRESUMO
The accurate identification of Acinetobacter spp. is challenging due to their high phenotypic and biochemical similarities. Because clinical relevance and antibiotic susceptibility are significantly different among different genomic species of Acinetobacter, the exact identification of A. baumannii is necessary and it can help us prevent inappropriate antibiotic use and inferior clinical care. This project employed a sequence-specific PCR assay for the rpoB region in A. baumannii to distinguish it from non-Acinetobacter baumannii Acinetobacter species. Moreover, a duplex PCR assay was used to detect blaOXA-51-like and gluconolactonase genes as a second identification method. In this study, 210 isolates of Acinetobacter spp. were considered and identified by PCR-sequencing of rpoB gene as a reference test. PCR-sequencing of rpoB revealed that 179 isolates were A. baumannii and 31 were non- A. baumannii Acinetobacter strains. PCR amplification targeting the rpoB gene as the first method, detected 182 isolates of A. baumannii, while duplex PCR assay confirmed 163 isolates as A. baumannii. Data analysis indicated that the sensitivities of sequence-specific PCR of the rpoB gene and duplex PCR assay were 100% and 91.06%, respectively, while specificities were 91.18% and 100%, respectively. Given the data, it was revealed that these two methods showed a reasonable potential for the accurate identification of A. baumannnii from non- A. baumannii species. Sequence-specific PCR assay for the rpoB gene and duplex PCR assay for blaOXA-51-like and gluconolactonase genes are rapid, reliable and cost-effective methods which can be used in clinical laboratories for the accurate identification of A. baumannii.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Infecções por Acinetobacter/diagnóstico , Acinetobacter baumannii/genética , Humanos , Laboratórios Clínicos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , beta-LactamasesRESUMO
PURPOSE: Multi-drug resistant (MDR) Acinetobacter baumannii has introduced a worldwide health crisis. The purposes of this study were to characterize the clonal relatedness among MDR clinical strains and to introduce a new two-locus typing method confirmed by multi-locus sequence typing (MLST). METHODOLOGY: In this study, we determined antimicrobial resistance, detected genes associated with carbapenem resistance and characterized clonal relatedness among 99 clinical isolates extracted from 82 hospitalized inpatients in a university hospital. RESULTS: Of the 99 A. baumannii isolates, 92.9% (92/99) were resistant to imipenem and 97.9% (97/99) had an MDR profile. We found that the high prevalence of blaVIM [94.9% (94/99)] and blaOXA-23-like [93.93% (93/99)] is the main mechanism of carbapenem resistance. This study proposes a new two-locus typing (blaOXA-51-like and ampC) method for the rapid identification of clonal complexes (CCs). The results of this method and confirmation by MLST show that clinical isolates carry blaOXA-68 as well as ampC-10 or ampC-20 genes belonging to CC10 (ST10); blaOXA-66 and ampC-2 belonging to CC2 (ST2); and blaOXA-71 and ampC-3 belonging to CC3 (ST3). One isolate had blaOXA-90 with an undetermined allele number of ampC belonging to ST513. CONCLUSION: The high prevalence of MDR strains and the circulation of four limited clones, including ST10 (45/99), ST2 (41/99), ST3 (12/99) and ST513 (1/99), in the clinical setting highlights the importance of a rigorous infection control programme. The two-locus typing method has more discrimination than the application of each method separately and it could be applied for the rapid determination of the CC without performing MLST.