Browsing by Author "Hanson, Blake"
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Publication Clinical characteristics, microbiology and outcomes of a cohort of patients treated with ceftolozane/tazobactam in acute care inpatient facilities, Houston, Texas, USA(2023) Tran, Truc; Cabrera, Nicolo; Gonzales, Anne; Carlson, Travis; Alnezary, Faris; Miller, William; Sakurai, Aki; Dinh, An; Rydell, Kirsten; Rios, Rafael; Diaz, Lorena; Hanson, Blake; Munita, Jose M.; Pedroza, Claudia; Shelburne, Samuel; Aitken, Samuel; Garey, Kevin; Dillon, Ryan; Puzniak, Laura; Arias, CesarBackground: Ceftolozane/tazobactam is a β-lactam/β-lactamase inhibitor combination with activity against a variety of Gram-negative bacteria, including MDR Pseudomonas aeruginosa. This agent is approved for hospital-acquired and ventilator-associated bacterial pneumonia. However, most real-world outcome data come from small observational cohorts. Thus, we sought to evaluate the utilization of ceftolozane/tazobactam at multiple tertiary hospitals in Houston, TX, USA. Methods: We conducted a multicentre retrospective study of patients receiving at least 48 h of ceftolozane/tazobactam therapy from January 2016 through to September 2019 at two hospital systems in Houston. Demographic, clinical and microbiological data were collected, including the infecting bacterial isolate, when available. The primary outcome was composite clinical success at hospital discharge. Secondary outcomes included in-hospital mortality and clinical disposition at 14 and 30 days post ceftolozane/tazobactam initiation. Multivariable logistic regression analysis was used to identify predictors of the primary outcome and mortality. Recovered isolates were tested for susceptibility to ceftolozane/tazobactam and underwent WGS. Results: A total of 263 patients were enrolled, and composite clinical success was achieved in 185 patients (70.3%). Severity of illness was the most consistent predictor of clinical success. Combination therapy with ceftolozane/tazobactam and another Gram-negative-active agent was associated with reduced odds of clinical success (OR 0.32, 95% CI 0.16-0.63). Resistance to ceftolozane/tazobactam was noted in 15.4% of isolates available for WGS; mutations in ampC and ftsI were common but did not cluster with a particular ST. Conclusions: Clinical success rate among this patient cohort treated with ceftolozane/tazobactam was similar compared with previous experiences. Ceftolozane/tazobactam remains an alternative agent for treatment of susceptible isolates of P. aeruginosa.Item Contemporary Clinical and Molecular Epidemiology of Vancomycin-Resistant Enterococcal Bacteremia: A Prospective Multicenter Cohort Study (VENOUS I)(2021) Contreras, Germán; Munita, José; Simar, Shelby; Luterbach, Courtney; Dinh, An Q.; Rydell, Kirsten; Sahasrabhojane, Pranoti; Rios, Rafael; Díaz, Lorena; Reyes, Katherine; Zervos, Marcus; Misikir, Helina; Sánchez, Gabriela; Liu, Catherine; Doi, Yohei; Abbo, Lilian; Shimose, Luis; Seifert, Harald; Gudiol, Carlota; Barberis, Fernanda; Pedroza, Claudia; Aitken, Samuel; Shelburne, Samuel; Duin, David; Tran, Truc; Hanson, Blake; Arias, CesarBackground: Vancomycin-resistant enterococci (VRE) are major therapeutic challenges. Prospective contemporary data characterizing the clinical and molecular epidemiology of VRE bloodstream infections (BSIs) are lacking. Methods: The Vancomycin-Resistant Enterococcal BSI Outcomes Study (VENOUS I) is a prospective observational cohort of adult patients with enterococcal BSI in 11 US hospitals. We included patients with Enterococcus faecalis or Enterococcus faecium BSI with ≥1 follow-up blood culture(s) within 7 days and availability of isolate(s) for further characterization. The primary study outcome was in-hospital mortality. Secondary outcomes were mortality at days 4, 7, 10, 12, and 15 after index blood culture. A desirability of outcome ranking was constructed to assess the association of vancomycin resistance with outcomes. All index isolates were subjected to whole genome sequencing. Results: Forty-two of 232 (18%) patients died in hospital and 39 (17%) exhibited microbiological failure (lack of clearance in the first 4 days). Neutropenia (hazard ratio [HR], 3.13), microbiological failure (HR, 2.4), VRE BSI (HR, 2.13), use of urinary catheter (HR, 1.85), and Pitt BSI score ≥2 (HR, 1.83) were significant predictors of in-hospital mortality. Microbiological failure was the strongest predictor of in-hospital mortality in patients with E faecium bacteremia (HR, 5.03). The impact of vancomycin resistance on mortality in our cohort changed throughout the course of hospitalization. Enterococcus faecalis sequence type 6 was a predominant multidrug-resistant lineage, whereas a heterogeneous genomic population of E faecium was identified. Conclusions: Failure of early eradication of VRE from the bloodstream is a major factor associated with poor outcomes.Publication Dynamics of the MRSA Population in a Chilean Hospital: a Phylogenomic Analysis (2000-2016)(2023) Martínez, José; Planet, Paul; Spencer, Maria; Rivas, Lina; Díaz, Lorena; Moustafa, Ahmed; Riquelme, Roberto; Alcalde, Manuel; Hanson, Blake; Carvajal, Lina; Rincón, Sandra; Reyes, Jinnethe; Lam, Marusella; Calderon, Juan; Araos, Rafael; García, Patricia; Arias, César; Munita, Jose M.The global dissemination of methicillin-resistant Staphylococcus aureus (MRSA) is associated with the emergence and establishment of clones in specific geographic areas. The Chilean-Cordobes clone (ChC) (ST5-SCCmecI) has been the predominant MRSA clone in Chile since its first description in 1998, despite the report of other emerging MRSA clones in recent years. Here, we characterize the evolutionary history of MRSA from 2000 to 2016 in a Chilean tertiary health care center using phylogenomic analyses. We sequenced 469 MRSA isolates collected between 2000 and 2016. We evaluated the temporal trends of the circulating clones and performed a phylogenomic reconstruction to characterize the clonal dynamics. We found a significant increase in the diversity and richness of sequence types (STs; Spearman r = 0.8748, P < 0.0001) with a Shannon diversity index increasing from 0.221 in the year 2000 to 1.33 in 2016, and an effective diversity (Hill number; q = 2) increasing from 1.12 to 2.71. The temporal trend analysis revealed that in the period 2000 to 2003 most of the isolates (94.2%; n = 98) belonged to the ChC clone. However, since then, the frequency of the ChC clone has decreased over time, accounting for 52% of the collection in the 2013 to 2016 period. This decline was accompanied by the rise of two emerging MRSA lineages, ST105-SCCmecII and ST72-SCCmecVI. In conclusion, the ChC clone remains the most frequent MRSA lineage, but this lineage is gradually being replaced by several emerging clones, the most important of which is clone ST105-SCCmecII. To the best of our knowledge, this is the largest study of MRSA clonal dynamics performed in South America. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is a major public health pathogen that disseminates through the emergence of successful dominant clones in specific geographic regions. Knowledge of the dissemination and molecular epidemiology of MRSA in Latin America is scarce and is largely based on small studies or more limited typing techniques that lack the resolution to represent an accurate description of the genomic landscape. We used whole-genome sequencing to study 469 MRSA isolates collected between 2000 and 2016 in Chile providing the largest and most detailed study of clonal dynamics of MRSA in South America to date. We found a significant increase in the diversity of MRSA clones circulating over the 17-year study period. Additionally, we describe the emergence of two novel clones (ST105-SCCmecII and ST72-SCCmecVI), which have been gradually increasing in frequency over time. Our results drastically improve our understanding of the dissemination and update our knowledge about MRSA in Latin America.Publication Global epidemiology and clinical outcomes of carbapenem-resistant Pseudomonas aeruginosa and associated carbapenemases (POP): a prospective cohort study(2023) Reyes, Jinnethe; Komarow, Lauren; Chen, Liang; Ge, Lizhao; Hanson, Blake; Cober, Eric; Herc, Erica; Alenazi, Thamer; Kaye, Keith; Garcia, Julia; Li, Lanjuan; Kanj, Souha; Liu, Zhengyin; Oñate, Jose; Salata, Robert; Marimuthu, Kalisvar; Gao, Hainv; Zong, Zhiyong; Valderrama, Sandra; Yu, Yunsong; Tambyah, Paul; Weston, Gregory; Salcedo, Soraya; Abbo, Lillian; Xie, Qing; Ordoñez, Karen; Wang, Minggui; Stryjewski, Martin; Munita, Jose M.; Paterson, David; Evans, Scott; Hill, Carol; Baum, Keri; Bonomo, Robert; Kreiswirth, Barry; Virginia, Maria; Pate, Robin; Arias, Cesar; Chambers, Henry; Fowler,Vance; Doi, Yohei; Van Duin, David; Satlin, Michael; Antibacterial Resistance Leadership Group and Multi-Drug Resistant Organism Network InvestigatorsBackground: Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a global threat, but the distribution and clinical significance of carbapenemases are unclear. The aim of this study was to define characteristics and outcomes of CRPA infections and the global frequency and clinical impact of carbapenemases harboured by CRPA. Methods: We conducted an observational, prospective cohort study of CRPA isolated from bloodstream, respiratory, urine, or wound cultures of patients at 44 hospitals (10 countries) between Dec 1, 2018, and Nov 30, 2019. Clinical data were abstracted from health records and CRPA isolates were whole-genome sequenced. The primary outcome was 30-day mortality from the day the index culture was collected. We compared outcomes of patients with CRPA infections by infection type and across geographic regions and performed an inverse probability weighted analysis to assess the association between carbapenemase production and 30-day mortality. Findings: We enrolled 972 patients (USA n=527, China n=171, south and central America n=127, Middle East n=91, Australia and Singapore n=56), of whom 581 (60%) had CRPA infections. 30-day mortality differed by infection type (bloodstream 21 [30%] of 69, respiratory 69 [19%] of 358, wound nine [14%] of 66, urine six [7%] of 88; p=0·0012) and geographical region (Middle East 15 [29%] of 52, south and central America 20 [27%] of 73, USA 60 [19%] of 308, Australia and Singapore three [11%] of 28, China seven [6%] of 120; p=0·0002). Prevalence of carbapenemase genes among CRPA isolates also varied by region (south and central America 88 [69%] of 127, Australia and Singapore 32 [57%] of 56, China 54 [32%] of 171, Middle East 27 [30%] of 91, USA ten [2%] of 527; p<0·0001). KPC-2 (n=103 [49%]) and VIM-2 (n=75 [36%]) were the most common carbapenemases in 211 carbapenemase-producing isolates. After excluding USA patients, because few US isolates had carbapenemases, patients with carbapenemase-producing CRPA infections had higher 30-day mortality than those with non-carbapenemase-producing CRPA infections in both unadjusted (26 [22%] of 120 vs 19 [12%] of 153; difference 9%, 95% CI 3-16) and adjusted (difference 7%, 95% CI 1-14) analyses.Interpretation: The emergence of different carbapenemases among CRPA isolates in different geographical regions and the increased mortality associated with carbapenemase-producing CRPA infections highlight the therapeutic challenges posed by these organisms. Funding: National Institutes of Health.Publication Multiomics characterization of methicillin-resistant Staphylococcus aureus (MRSA) isolates with heterogeneous intermediate resistance to vancomycin (hVISA) in Latin America(2023) Castro, Betsy E.; Ríos, Rafael; Carvajal, Lina P.; Vargas, Mónica L.; Cala, Mónica P.; León, Lizeth; Hanson, Blake; Dinh, An Q.; Ortega-Recalde, Oscar; Seas, Carlos; Munita, José; Arias, Cesar A.; Rincón, Sandra; Reyes, Jinnethe; Díaz, LorenaBackground: Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) compromise the clinical efficacy of vancomycin. The hVISA isolates spontaneously produce vancomycin-intermediate Staphylococcus aureus (VISA) cells generated by diverse and intriguing mechanisms. Objective: To characterize the biomolecular profile of clinical hVISA applying genomic, transcriptomic and metabolomic approaches. Methods: 39 hVISA and 305 VSSA and their genomes were included. Core genome-based Bayesian phylogenetic reconstructions were built and alterations in predicted proteins in VISA/hVISA were interrogated. Linear discriminant analysis and a Genome-Wide Association Study were performed. Differentially expressed genes were identified in hVISA-VSSA by RNA-sequencing. The undirected profiles of metabolites were determined by liquid chromatography and hydrophilic interaction in six CC5-MRSA. Results: Genomic relatedness of MRSA associated to hVISA phenotype was not detected. The change Try38 →His in Atl (autolysin) was identified in 92% of the hVISA. We identified SNPs and k-mers associated to hVISA in 11 coding regions with predicted functions in virulence, transport systems, carbohydrate metabolism and tRNA synthesis. Further, capABCDE, sdrD, esaA, esaD, essA and ssaA genes were overexpressed in hVISA, while lacABCDEFG genes were downregulated. Additionally, valine, threonine, leucine tyrosine, FAD and NADH were more abundant in VSSA, while arginine, glycine and betaine were more abundant in hVISA. Finally, we observed altered metabolic pathways in hVISA, including purine and pyrimidine pathway, CoA biosynthesis, amino acid metabolism and aminoacyl tRNA biosynthesis. Conclusions: Our results show that the mechanism of hVISA involves major changes in regulatory systems, expression of virulence factors and reduction in glycolysis via TCA cycle. This work contributes to the understanding of the development of this complex resistance mechanism in regional strains.Publication Multisite Detection of Tn 1549-Mediated vanB Vancomycin Resistance in Multidrug-Resistant Enterococcus faecalis ST6 in Texas and Florida(2023) Simar, Shelby; Tran, Truc; Rydell, Kirsten; Panesso, Diana; Contreras, German; Munita, Jose M.; Cifuentes. Renzo; Abbo, Lilian; Sahasrabhojane, Pranoti; Dinh, An; Axell-House, Dierdre; Savidge, Tor; Shelburne, Samuel; Hanson, Blake; Arias, CesarIn the United States, vanB-mediated resistance in enterococci is rare. We characterized three sequence type (ST) 6, vancomycin-resistant Enterococcus faecalis isolates causing bacteremia in unique patients in spatiotemporally distinct settings. Isolates were recovered between 2018 and 2020 in two cities in the United States (Houston, TX; Miami, FL). The isolates harbored the vanB operon on a chromosomally located Tn1549 transposon, and epidemiological data suggested multiple introductions of the vanB gene cluster into ST6 E. faecalis.Item Selective digestive decontamination with oral colistin plus gentamicin for persistent bacteraemia caused by non-carbapenemase-producing carbapenem-resistant Klebsiella pneumoniae in a neutropenic patient(2021) Spencer-Sandino, Maria; Riquelme-Neira, Roberto; Shropshire, William C.; Dinh, An Q.; González-Rocha, Gerardo; González-Muñoz, Paulina; Vera-Leiva, Alejandra; Araos, Rafael; Hanson, Blake; Arias, Cesar A; Munita, JoséCarbapenem-resistant Klebsiella pneumoniae (CRKp) have become an increasing public health problem worldwide. While most CRKp around the world harbour a carbapenemase enzyme, the clinical relevance of non-carbapenemase-producing CRKp (non-CP-CRKp) is increasingly recognized. Selective digestive decontamination (SDD) has been proven successful as a decolonization strategy for patients colonized with Gram-negatives in the ICU. However, it is not regularly used to treat invasive infections.