RESUMO
BACKGROUND: 16S rRNA methylase-producing Gram-negative bacteria are highly resistant to all clinically important aminoglycosides. We analyzed clinical strains of 16S rRNA methylase-producing Acinetobactor baumannii and Pseudomonas aeruginosa obtained from clinical isolates in medical settings in Vietnam. METHODS: From 2008 to 2011, 101 clinical strains of A. baumannii and 15 of P. aeruginosa were isolated from patients in intensive care units (ICUs) in two medical settings in Vietnam. Antimicrobial susceptibilities were determined using the microdilution method and epidemiological analysis was performed by pulsed-field gel electrophoresis and MLST. Genes encoding the 16S rRNA methylases, OXAs and CTX-Ms were analyzed by PCR and sequence analysis. RESULTS: 16S rRNA methylase-producing Gram-negative pathogens were detected in two hospitals in Vietnam. Of the 101 clinical isolates of A. baumannii and the 15 of P. aeruginosa isolated from two ICUs in these hospitals, 72 (71.3%) were highly resistant to amikacin, arbekacin and gentamicin, with MICs greater than 1,024 mg/L. The 16S rRNA methylases ArmA and RmtB were produced by 61 and 9 isolates of A. baumannii, respectively, and RmtB was produced by 2 isolates of P. aeruginosa. Moreover, 52 of the A. baumannii isolates producing 16S rRNA methylases harbored both blaOXA-23-like and blaOXA-51-like genes. Most A. baumannii isolates producing 16S rRNA methylase obtained in hospital A in Hanoi were ST91 and ST231, whereas most from hospital B in Ho Chi Minh City were ST136, ST195, and ST254. CONCLUSIONS: Gram-negative bacteria producing the 16S rRNA methylases ArmA and RmtB are emerging in medical settings in Vietnam. A. baumannii isolates in northern and southern regions of Vietnam may be of different lineages.
Assuntos
Acinetobacter baumannii/enzimologia , Proteínas de Bactérias/biossíntese , Infecção Hospitalar/microbiologia , Farmacorresistência Bacteriana/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Metiltransferases/biossíntese , Pseudomonas aeruginosa/enzimologia , RNA Ribossômico 16S/metabolismo , Acinetobacter baumannii/genética , Acinetobacter baumannii/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Humanos , Metiltransferases/genética , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/isolamento & purificação , VietnãRESUMO
INTRODUCTION: The prevalence of gene mutations in hemophagocytic lymphohistiocytosis (HLH) varied between studies. Thus far, data on the genetic background of HLH in Vietnamese patients are limited. METHODS: We recruited 94 HLH patients and analyzed for the 4 genes using Sanger sequencing technology. RESULTS: Pathogenic variants were observed in 36 (38.29%) patients, including 27 in UNC13D, 5 in STXBP2, 3 in PRF1, and 2 in STX11 (one patient with digenic variants in both UNC13D and STX11). Monoallelic variants accounted for 77.8% of all cases with mutation. A total of 23 different types of pathogenic variants were documented in the 4 genes tested, including 15 in UNC13D, 3 in PRF1, 3 in STXBP2, and 2 in STX11. Interestingly, the novel splicing variant c.3151G>A in UNC13D was recurrently identified in 8 unrelated patients. CONCLUSION: Vietnamese patients with HLH showed a distinct genetic variant spectrum, in which UNC13D is the predominant genetic lesion associated with HLH.