Comparison of Whole Genome Sequencing and Repetitive Element PCR for Multidrug- Resistant Pseudomonas aeruginosa Strain Typing

Author(s):  
Jennifer K. Spinler ◽  
Sabeen Raza ◽  
Santosh Thapa ◽  
Alamelu Venkatachalam ◽  
Tiana Scott ◽  
...  
Author(s):  
Abigail M. Rubio ◽  
Ellen G. Kline ◽  
Chelsea E. Jones ◽  
Liang Chen ◽  
Barry N. Kreiswirth ◽  
...  

We compared the in vitro susceptibility of multidrug-resistant Pseudomonas aeruginosa isolates collected before and after treatment-emergent resistance to ceftolozane-tazobactam. Median baseline and post-exposure ceftolozane-tazobactam MICs were 2 and 64 μg/mL, respectively. Whole-genome sequencing identified treatment-emergent mutations in ampC among 79% (11/14) of paired isolates. AmpC mutations were associated with cross-resistance to ceftazidime-avibactam, but increased susceptibility to piperacillin-tazobactam and imipenem. Eighty-one percent (12/16) of ceftolozane-tazobactam resistant isolates with ampC mutations were susceptible to imipenem-relebactam.


2021 ◽  
Vol 9 (10) ◽  
pp. 2046
Author(s):  
I-Chen Li ◽  
Rayean Wu ◽  
Chung-Wen Hu ◽  
Keh-Ming Wu ◽  
Zeng-Weng Chen ◽  
...  

Over the last decade, Salmonella enterica serovar Schwarzengrund has become more prevalent in Asia, Europe, and the US with the simultaneous emergence of multidrug-resistant isolates. As these pathogens are responsible for many sporadic illnesses and chronic complications, as well as outbreaks over many countries, improved surveillance is urgently needed. For 20 years, pulsed-field gel electrophoresis (PFGE) has been the gold standard for determining bacterial relatedness by targeting genome-wide restriction enzyme polymorphisms. Despite its utility, recent studies have reported that PFGE results correlate poorly with that of closely related outbreak strains and clonally dominant endemic strains. Due to these concerns, alternative amplification-based molecular methods for bacterial strain typing have been developed, including clustered regular interspaced short palindromic repeats (CRISPR) and multilocus sequence typing (MLST). Furthermore, as the cost of sequencing continues to decrease, whole genome sequencing (WGS) is poised to replace other molecular strain typing methods. In this study, we assessed the discriminatory power of PFGE, CRISPR, MLST, and WGS methods to differentiate between 23 epidemiologically unrelated S. enterica serovar Schwarzengrund isolates collected over an 18-year period from distinct locations in Taiwan. The discriminatory index (DI) of each method for different isolates was calculated, resulting in values between 0 (not discriminatory) and 1 (highly discriminatory). Our results showed that WGS has the greatest resolution (DI = 0.982) compared to PFGE (DI = 0.938), CRISPR (DI = 0.906), and MLST (DI = 0.463) methods. In conclusion, the WGS typing approach was shown to be the most sensitive for S. enterica serovar Schwarzengrund fingerprinting.


2018 ◽  
Vol 40 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Alison L. Galdys ◽  
Jane W. Marsh ◽  
Edgar Delgado ◽  
A. William Pasculle ◽  
Marissa Pacey ◽  
...  

AbstractObjectiveRecovery of multidrug-resistant (MDR) Pseudomonas aeruginosa and Klebsiella pneumoniae from a cluster of patients in the medical intensive care unit (MICU) prompted an epidemiologic investigation for a common exposure.MethodsClinical and microbiologic data from MICU patients were retrospectively reviewed, MICU bronchoscopes underwent culturing and borescopy, and bronchoscope reprocessing procedures were reviewed. Bronchoscope and clinical MDR isolates epidemiologically linked to the cluster underwent molecular typing using pulsed-field gel electrophoresis (PFGE) followed by whole-genome sequencing.ResultsOf the 33 case patients, 23 (70%) were exposed to a common bronchoscope (B1). Both MDR P. aeruginosa and K. pneumonia were recovered from the bronchoscope’s lumen, and borescopy revealed a luminal defect. Molecular testing demonstrated genetic relatedness among case patient and B1 isolates, providing strong evidence for horizontal bacterial transmission. MDR organism (MDRO) recovery in 19 patients was ultimately linked to B1 exposure, and 10 of 19 patients were classified as belonging to an MDRO pseudo-outbreak.ConclusionsSurveillance of bronchoscope-derived clinical culture data was important for early detection of this outbreak, and whole-genome sequencing was important for the confirmation of findings. Visualization of bronchoscope lumens to confirm integrity should be a critical component of device reprocessing.


2015 ◽  
Vol 53 (8) ◽  
pp. 2622-2631 ◽  
Author(s):  
Jane F. Turton ◽  
Laura Wright ◽  
Anthony Underwood ◽  
Adam A. Witney ◽  
Yuen-Ting Chan ◽  
...  

Whole-genome sequencing (WGS) was carried out on 87 isolates of sequence type 111 (ST-111) of Pseudomonas aeruginosa collected between 2005 and 2014 from 65 patients and 12 environmental isolates from 24 hospital laboratories across the United Kingdom on an Illumina HiSeq instrument. Most isolates (73) carried VIM-2, but others carried IMP-1 or IMP-13 (5) or NDM-1 (1); one isolate had VIM-2 and IMP-18, and 7 carried no metallo-beta-lactamase (MBL) gene. Single nucleotide polymorphism analysis divided the isolates into distinct clusters; the NDM-1 isolate was an outlier, and the IMP isolates and 6/7 MBL-negative isolates clustered separately from the main set of 73 VIM-2 isolates. Within the VIM-2 set, there were at least 3 distinct clusters, including a tightly clustered set of isolates from 3 hospital laboratories consistent with an outbreak from a single introduction that was quickly brought under control and a much broader set dominated by isolates from a long-running outbreak in a London hospital likely seeded from an environmental source, requiring different control measures; isolates from 7 other hospital laboratories in London and southeast England were also included. Bayesian evolutionary analysis indicated that all the isolates shared a common ancestor dating back ∼50 years (1960s), with the main VIM-2 set separating approximately 20 to 30 years ago. Accessory gene profiling revealed blocks of genes associated with particular clusters, with some having high similarity (≥95%) to bacteriophage genes. WGS of widely found international lineages such as ST-111 provides the necessary resolution to inform epidemiological investigations and intervention policies.


2019 ◽  
Vol 57 (9) ◽  
Author(s):  
Xuebing Wang ◽  
Haijian Zhou ◽  
Dongke Chen ◽  
Pengcheng Du ◽  
Ruiting Lan ◽  
...  

ABSTRACT Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen that occurs primarily among immunocompromised and chronically ill patients. However, little is known about the genomic diversity of C. striatum, which contributes to its long-term persistence and transmission in hospitals. In this study, a total of 192 C. striatum isolates obtained from 14 September 2017 to 29 March 2018 in a hospital in Beijing, China, were analyzed by antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Whole-genome sequencing was conducted on 91 isolates. Nearly all isolates (96.3%, 183/190) were MDR. The highest resistance rate was observed for ciprofloxacin (99.0%, 190/192), followed by cefotaxime (90.6%, 174/192) and erythromycin (89.1%, 171/192). PFGE separated the 192 isolates into 79 pulsotypes, and differences in core genome single-nucleotide polymorphisms (SNPs) partitioned the 91 isolates sequenced into four clades. Isolates of the same pulsotype were identical or nearly identical at the genome level, with some exceptions. Two dominant subclones, clade 3a, and clade 4a, were responsible for the hospital-wide dissemination. Genomic analysis further revealed nine resistance genes mobilized by eight unique cassettes. PFGE and whole-genome sequencing revealed that the C. striatum isolates studied were the result mainly of predominant clones spreading in the hospital. C. striatum isolates in the hospital progressively acquired resistance to antimicrobial agents, demonstrating that isolates of C. striatum may adapt rapidly through the acquisition and accumulation of resistance genes and thus evolve into dominant and persistent clones. These insights will be useful for the prevention of C. striatum infection in hospitals.


2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S309-S309 ◽  
Author(s):  
Mariana Castanheira ◽  
Jill Lindley ◽  
Holly Huynh ◽  
Rodrigo E Mendes ◽  
Olga Lomovskaya

Abstract Background CREs have been described worldwide and these isolates are often multidrug resistant with few therapeutic options remaining active against them. New β-lactam (BL)/β-lactamase inhibitor (BLI) combinations recently approved are active against KPC and some OXA-48 producers, but not against isolates producing metallo-β-lactamases (MBLs). We evaluated the activity of QPX7728 (QPX), a novel BLI paired with various BLs against a collection of CRE isolates characterized for the presence of carbapenemases. Methods A total of 508 CRE clinical isolates were susceptibility (S) tested by reference broth microdilution methods against meropenem (MER), tebipenem (TEB), cefepime (FEP), ceftolozane (TOL), and ertapenem (ETP), and meropenem (MEM) combined with QPX at fixed 2, 4, and 8 mg/L. Agents were provided by Qpex Biopharma except for FEP, ETP, and MEM. Carbapenemases were detected using PCR/sequencing or whole-genome sequencing. Results All BLs had limited activity against CRE isolates (MIC50/90, ≥32/ >32 mg/L) and QPX lowered the MIC for all agents (figure). Against 157 isolates carrying serine-carbapenemase (SCarb) genes (153 KPC-producers), MEM or ETP plus QPX at fixed 4 or 8 mg/L displayed MIC50 at ≤ 0.03 mg/L and MIC90 ranging from 0.12 to 0.5 mg/L. QPX lowered the FEP or TOL MIC50 to ≤ 0.25 mg/L and MIC90 to 0.25, 0.5 or 1 mg/L depending on the BLI concentration. Over 98.0% of the 150 isolates harboring OXA-48-like genes were inhibited by FEP, TOL, ETP or MEM plus QPX at ≤2 mg/L. Similarly, MEM, FEP, TOL and ETP + QPX inhibited >98.0% of the 51 CREs that did not carry carbapenemases at ≤2 mg/L when using a higher BLI concentration. The activity of FEP (MIC50/90, 0.06/1 mg/L), ETP (MIC50/90, 0.03/4 mg/L), and MEM (MIC50/90, ≤ 0.015/2 mg/L) was mostly restored when 8 mg/L of QPX was combined with these agents and tested against 150 MBL-producing isolates. Conclusion QPX restored the activity of several BLs when tested against 508 CRE isolates that include 157 harboring SCarb, 150 OXA-48-like-producers, and 150 MBL-producing isolates. Further development of this BLI with inhibitory activity against all carbapenemase types seems warranted. Disclosures All authors: No reported disclosures.


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