scholarly journals Application of Whole-Genome Sequencing to Investigation of a Prolonged Outbreak Caused by Multidrug-Resistant Acinetobacter Baumannii at a Large Academic Burn Center

2015 ◽  
Vol 2 (suppl_1) ◽  
Author(s):  
Hajime Kanamori ◽  
Christian Parobek ◽  
David Weber ◽  
William Rutala ◽  
Jonathan Juliano
Author(s):  
Peechanika Chopjitt ◽  
Anusak Kerdsin ◽  
Dan Takeuchi ◽  
Rujirat Hatrongjit ◽  
Parichart Boueroy ◽  
...  

Background:: Acinetobacter baumannii is recognized as a majority opportunistic nosocomial pathogen and caus-ing hospital-acquired infection worldwide. The increasing prevalence of extensively drug-resistant Acinetobacter baumannii (XDRAB) has become a rising concern in healthcare facilities and has impeded public health due to limitation of therapeutic options and are associated with high morbidity and mortality as well as longer hospitalization. Whole-genome sequencing of highly multidrug resistant A. baumannii will increase understanding of resistant mechanisms, the emergence of novel re-sistance, genetic relationships among the isolates, source tracking, and treatment decisions in selected patients. Objective:: This study revealed the genomic analysis to explore blaOXA-23 harboring XDRAB isolates in Thailand. Methods:: Whole-genome sequencing of the two XDRAB isolates was carried out on a HiSeq2000 Illumina platform and susceptibility on antimicrobials was conducted. Results:: Both isolates revealed sequence types of international, clone II-carrying, multiple antimicrobial-resistant genes—ST195 and ST451. They were resistant to antimicrobial agents in all drug classes tested for Acinetobacter spp. They carried 18 antimicrobial-resistant genes comprising of 4 -lactamase genes (blaOXA-23, blaOXA-66, blaTEM-1D, blaADC-25), 4 aminogly-coside-resistant genes (armA, aph(3')-Ia, aph(3'')-Ib, aph(6)-Id), 3 macrolide-resistant genes (amvA, mphE, msrE), 1 sulfon-amide-resistant gene (sul-2), 2 tetracycline-resistant genes (tetB, tetR), 1 resistant-nodulation-cell division (RND) antibiotic efflux pump gene cluster, 2 major facilitator superfamily (MFS) antibiotic efflux pump genes (abaF, abaQ), and 1 small multidrug-resistant (SMR) antibiotic efflux pump gene (abeS). Mutation of gyrA (S81L) occurred in both isolates. Conclusions:: Whole-genome sequencing revealed both blaOXA-23 harboring XDRAB isolates were clustered under interna-tional clone II with difference STs and carrying multiple antimicrobial-resistant genes conferred their resistance to antimi-crobial agents. Inactivation of antimicrobials and target modification by enzymes, and pumping antibiotics by efflux pump are mainly resistance mechanism of the XDRAB in this study.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kah Ern Ten ◽  
Muhammad Zarul Hanifah Md Zoqratt ◽  
Qasim Ayub ◽  
Hock Siew Tan

Abstract Objective The nosocomial pathogen, Acinetobacter baumannii, has acquired clinical significance due to its ability to persist in hospital settings and survive antibiotic treatment, which eventually resulted in the rapid spread of this bacterium with antimicrobial resistance (AMR) phenotypes. This study used a multidrug-resistant A. baumannii (strain ATCC BAA1605) as a model to study the genomic features of this pathogen. Results One circular chromosome and one circular plasmid were discovered in the complete genome of A. baumannii ATCC BAA1605 using whole-genome sequencing. The chromosome is 4,039,171 bp long with a GC content of 39.24%. Many AMR genes, which confer resistance to major classes of antibiotics (beta-lactams, aminoglycosides, tetracycline, sulphonamides), were found on the chromosome. Two genomic islands were predicted on the chromosome, one of which (Genomic Island 1) contains a cluster of AMR genes and mobile elements, suggesting the possibility of horizontal gene transfer. A subtype I-F CRISPR-Cas system was also identified on the chromosome of A. baumannii ATCC BAA1605. This study provides valuable genome data that can be used as a reference for future studies on A. baumannii. The genome of A. baumannii ATCC BAA1605 has been deposited at GenBank under accession no. CP058625 and CP058626.


2021 ◽  
Vol 12 ◽  
Author(s):  
Pu Mao ◽  
Xiaolong Deng ◽  
Leping Yan ◽  
Ya Wang ◽  
Yueting Jiang ◽  
...  

The nosocomial pathogen Acinetobacter baumannii is a frequent cause of healthcare-acquired infections, particularly in critically ill patients, and is of serious concern due to its potential for acquired multidrug resistance. Whole-genome sequencing (WGS) is increasingly used to obtain a high-resolution view of relationships between isolates, which helps in controlling healthcare-acquired infections. Here, we conducted a retrospective study to identify epidemic situations and assess the percentage of transmission in intensive care units (ICUs). Multidrug-resistant A. baumannii (MDR-AB) were continuously isolated from the lower respiratory tract of different patients (at the first isolation in our ICU). We performed WGS, pulsed-field gel electrophoresis (PFGE), and multilocus-sequence typing (MLST) analyses to elucidate bacterial relatedness and to compare the performance of conventional methods with WGS for typing MDR-AB. From June 2017 to August 2018, A. baumannii complex strains were detected in 124 of 796 patients during their ICU stays, 103 of which were MDR-AB. Then we subjected 70 available MDR-AB strains to typing with WGS, PFGE, and MLST. Among the 70 A. baumannii isolates, 38 (54.29%) were isolated at admission, and 32(45.71%) were acquisition isolates. MLST identified 12 unique sequence types, a novel ST (ST2367) was founded. PFGE revealed 16 different pulsotypes. Finally, 38 genotypes and 23 transmissions were identified by WGS. Transmission was the main mode of MDR-AB acquisition in our ICU. Our results demonstrated that WGS was a discriminatory technique for epidemiological healthcare-infection studies. The technique should greatly benefit the identification of epidemic situations and controlling transmission events in the near future.


Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 201
Author(s):  
Sang Mee Hwang ◽  
Hee Won Cho ◽  
Tae Yeul Kim ◽  
Jeong Su Park ◽  
Jongtak Jung ◽  
...  

Carbapenem-resistant Acinetobacter baumannii (CRAB) outbreaks in hospital settings challenge the treatment of patients and infection control. Understanding the relatedness of clinical isolates is important in distinguishing outbreak isolates from sporadic cases. This study investigated 11 CRAB isolates from a hospital outbreak by whole-genome sequencing (WGS), utilizing various bioinformatics tools for outbreak analysis. The results of multilocus sequence typing (MLST), single nucleotide polymorphism (SNP) analysis, and phylogenetic tree analysis by WGS through web-based tools were compared, and repetitive element polymerase chain reaction (rep-PCR) typing was performed. Through the WGS of 11 A. baumannii isolates, three clonal lineages were identified from the outbreak. The coexistence of blaOXA-23, blaOXA-66, blaADC-25, and armA with additional aminoglycoside-inactivating enzymes, predicted to confer multidrug resistance, was identified in all isolates. The MLST Oxford scheme identified three types (ST191, ST369, and ST451), and, through whole-genome MLST and whole-genome SNP analyses, different clones were found to exist within the MLST types. wgSNP showed the highest discriminatory power with the lowest similarities among the isolates. Using the various bioinformatics tools for WGS, CRAB outbreak analysis was applicable and identified three discrete clusters differentiating the separate epidemiologic relationships among the isolates.


2019 ◽  
Vol 14 (15) ◽  
pp. 1281-1292 ◽  
Author(s):  
Giovanni Lorenzin ◽  
Erika Scaltriti ◽  
Franco Gargiulo ◽  
Francesca Caccuri ◽  
Giorgio Piccinelli ◽  
...  

Aim: This study aims to characterize clinical strains of Acinetobacter baumannii with an extensively drug-resistant phenotype. Methods: VITEK® 2, Etest® method and broth microdilution method for colistin were used. PCR analysis and multilocus sequence typing Pasteur scheme were performed to identify bla-OXA genes and genetic relatedness, respectively. Whole-genome sequencing analysis was used to characterize three isolates. Results: All the isolates were susceptible only to polymyxins. blaOXA-23-like gene was the only acquired carbapenemase gene in 88.2% of the isolates. Multilocus sequence typing identified various sequence types: ST2, ST19, ST195, ST577 and ST632. Two new sequence types, namely, ST1279 and ST1280, were detected by whole-genome sequencing. Conclusion: This study showed that carbapenem-resistant A. baumannii isolates causing infections in intensive care units almost exclusively produce OXA-23, underlining their frequent spread in Italy.


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