scholarly journals 13. Evaluation of Etest for Antibiotic Susceptibility and Minimum Inhibitory Concentration (MIC) Agreement Against pseudomonas Aeruginosa (psa) from Patients with Cystic Fibrosis (CF)

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S7-S8
Author(s):  
Maxwell J Lasko ◽  
Holly Huse ◽  
Joseph L Kuti ◽  
David P Nicolau

Abstract Background CF acute pulmonary exacerbations are often caused by PSA, including multi-drug resistant strains. Optimal antibiotic therapy is required to return lung function and should be guided by in vitro susceptibility results. There are sparse data on the performance of Etest relative to reference broth microdilution (BMD) for many newer drugs against CF PSA. Herein, we describe Etest performance with 10 anti-PSA antibiotics against CF isolates. Methods Contemporary, clinical PSA (n=105) isolated during pulmonary exacerbation from patients with CF were acquired from 3 US hospitals. MICs were assessed by BMD (reference) and Etest for aztreonam (ATM), cefepime (FEP), ceftazidime (CAZ), ceftazidime/avibactam (CZA), ceftolozane/tazobactam (C/T), ciprofloxacin (CIP), levofloxacin (LVX), meropenem (MEM), piperacillin/tazobactam (TZP), and tobramycin (TOB). Each respective MIC was completed in at least triplicate using the same inoculum between methods. Modal MICs for each method were compared by rates of essential agreement (EA), categorical agreement (CA), minor error (miE), major error (ME), and very major error (VME) rates. All miE, ME and VME were adjusted if within EA. Results Of the 105 PSA, 46% had a mucoid phenotype. Results are summarized in the Table. Median modal Etest MICs read 0–1 dilution higher (IQR: 0–1) than BMD. CA and EA ranged from 64–93% and 63–86%, respectively. Single VMEs occurred for ATM (2.9%) and CAZ (4.2%). For CZA, 2 VMEs were observed and both were within EA. Major errors were ≤3% except for ATM (3.3%), MEM (3.3%), CZA (5.3% with adjusted ME 2.1%*), and FEP (13%). Minor error rates were < 10% except for TZP, CIP, LEV, TOB, and FEP (13–29%), for which majority of miE were within EA (3/14, 11/16, 10/18, 13/19, 20/31, respectively). Performance was similar for non-mucoid and mucoid populations. Etest Performance Conclusion Etest methods performed well for most antibiotics against this challenging collection of PSA from CF patients. Laboratories should be cautious of miE and ME that may occur with certain antibiotics. Furthermore, our observations suggest laboratories confirm CZA results for isolates with MICs near the breakpoint. Disclosures Joseph L. Kuti, PharmD, Allergan (Speaker’s Bureau)bioMérieux (Research Grant or Support, Other Financial or Material Support, Speaker Honorarium)Melinta (Research Grant or Support)Merck & Co., Inc. (Research Grant or Support)Paratek (Speaker’s Bureau)Summit (Other Financial or Material Support, Research funding (clinical trials)) David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support)

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S667-S667
Author(s):  
Iris H Chen ◽  
David P Nicolau ◽  
Joseph L Kuti

Abstract Background I/R, a carbapenem-beta-lactamase inhibitor antibiotic, is active against most imipenem-resistant PSA, including MDR isolates. Combination therapy may enhance activity against MDR pathogens and suppress resistance. This study’s objective was to assess the efficacy of I/R compared with combinations including colistin (CST) or amikacin (AMK) against PSA in an IVPD model. Methods Human-simulated concentrations of I/R 500/250 mg every six hours, a total daily dose of CST 360 mg, and AMK 25 mg/kg daily were reproduced alone and in combination against 6 imipenem-non-susceptible PSA with I/R MICs of 1/4 to 8/4 mg/L in an IVPD over 24h. The primary endpoint was the difference in 24h colony forming units (CFU) between each combination regimen and its components alone. The log ratio differences of the area under the CFU curve were also calculated to compare the overall bacterial burden resulting from exposure to I/R alone with those treated by combination regimens. Emergence of resistance was tested at 24h using drug-containing plates at 3xMIC. Results I/R, CST, and AMK alone produced 24hCFU changes consistent with isolate MICs. One isolate (already I/R non-susceptible) developed I/R resistance, and 4 and 3 developed CST and AMK resistance, respectively. I/R plus CST suppressed all resistance and resulted in synergistic or additive interactions against three of six isolates with 24h CFU reductions ranging from -2.62 to -4.67 log10CFU/mL. This combination further reduced overall bacterial burden by 79-81% compared with I/R alone against two I/R-non-susceptible strains. I/R plus AMK also prevented resistance emergence but exhibited indifferent interactions against all isolates at 24h with the combined drugs achieving -0.51 to -3.33 log10CFU/mL reductions. Minor overall reductions in bacterial burden were observed relative to I/R alone. Conclusion I/R plus CST resulted in additivity or synergy against three of six PSA and prevented I/R and CST resistance, whereas the addition of AMK only suppressed resistance. The greatest overall reductions in bacterial burden, however, were observed with I/R plus CST against I/R-non-susceptible isolates, supporting targeted use of this combination against this phenotype when alternatives are unavailable. Disclosures David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support) Joseph L. Kuti, PharmD, Allergan (Speaker’s Bureau)bioMérieux (Research Grant or Support, Other Financial or Material Support, Speaker Honorarium)Melinta (Research Grant or Support)Merck & Co., Inc. (Research Grant or Support)Paratek (Speaker’s Bureau)Summit (Other Financial or Material Support, Research funding (clinical trials))


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S797-S797
Author(s):  
Maxwell J Lasko ◽  
David P Nicolau ◽  
Joseph L Kuti

Abstract Background Acute pulmonary exacerbations (APE) are a frequent cause of hospitalization for patients with CF. PSA is among the most common pathogen implicated in CF APE. Due to repetitive antibiotic courses, multidrug resistance (MDR) must be considered leaving few available intravenous antibiotic options. CZA and C/T are newer anti-PSA antibiotics that have been used to treat CF APE, but little data are available to compare their in vitro activity. Methods Non-duplicate, contemporary, clinical PSA (n=105) isolates were acquired from 85 patients during CF APE from 3 US hospital systems. MICs were assessed in at least triplicate by reference broth microdilution for C/T, CZA, aztreonam (ATM), cefepime (FEP), ceftazidime (CAZ), ciprofloxacin (CIP), levofloxacin (LVX), meropenem (MEM), piperacillin/tazobactam (TZP), and tobramycin (TOB). Current CLSI breakpoints were used to define susceptibility. Activity was further assessed in MDR, CAZ and MEM non-susceptible (NS) phenotypes. Results The mean patient age at isolate retrieval was 31 years (IQR: 21-43), and 20% were under 18 years. Mucoid morphology was observed in 48 (46%) isolates, and MDR defined in 41 (39%). Rates of susceptibility (MIC50/MIC90/%S) were: C/T (1/4/92%), CZA (2/8/90%), CAZ (4/64/68%), TZP (8/256/67%), TOB (2/32/63%), MEM (1/32/58%), ATM (8/64/57%), FEP (8/≥128/50%), CIP (2/8/27%), and LVX (4/16/24%). A mucoid phenotype did not alter %S (non-mucoid vs. mucoid) for C/T (93 vs. 92%) or CZA (91 vs. 88%). Among the 41 MDR PSA, activity was 2/16/83% and 4/16/76% for C/T and CZA, respectively. C/T, CZA, and MEM %S was 77, 69, and 23% for the 35 CAZ-NS isolates. C/T, CZA, and CAZ %S was 84, 77, and 39% for MEM-NS isolates. Conclusion These contemporary PSA from patients with CF displayed low susceptibility rates to most β-lactams, fluoroquinolones, and tobramycin, and MDR was common. C/T and CZA retained similarly high susceptibility against these isolates, including MDR strains and CAZ-NS/MEM-NS phenotypes. These data justify that both CT and CZA may be considered for CF APE due to PSA non-susceptible to current standard of care treatment options. Disclosures David P. Nicolau, PharmD, Cepheid (Other Financial or Material Support, Consultant, speaker bureau member or has received research support.)Merck & Co., Inc. (Consultant, Grant/Research Support, Speaker’s Bureau)Wockhardt (Grant/Research Support) Joseph L. Kuti, PharmD, Allergan (Speaker’s Bureau)bioMérieux (Research Grant or Support, Other Financial or Material Support, Speaker Honorarium)Melinta (Research Grant or Support)Merck & Co., Inc. (Research Grant or Support)Paratek (Speaker’s Bureau)Summit (Other Financial or Material Support, Research funding (clinical trials))


Author(s):  
Maxwell J. Lasko ◽  
Holly K. Huse ◽  
David P. Nicolau ◽  
Joseph L. Kuti

Abstract Objectives Cystic fibrosis (CF) acute pulmonary exacerbations are often caused by Pseudomonas aeruginosa, including multi-drug resistant strains. Optimal antibiotic therapy is required to return lung function and should be guided by in vitro susceptibility results. There are sparse data describing ETEST performance for CF isolates using contemporary isolates, methods and interpretation, as well as novel antibiotics, such as ceftazidime–avibactam and ceftolozane–tazobactam. Methods Pseudomonas aeruginosa (n = 105) isolated during pulmonary exacerbation from patients with CF were acquired from 3 US hospitals. Minimum inhibitory concentrations (MICs) were assessed by reference broth microdilution (BMD) and ETEST for aztreonam, cefepime, ceftazidime, ceftazidime–avibactam, ceftolozane–tazobactam, ciprofloxacin, levofloxacin, meropenem, piperacillin–tazobactam, and tobramycin. Broth microdilution was conducted in concordance with the Clinical and Laboratory Standards Institute M100. ETEST methodology reflected package insert recommendations. Performance of ETEST strips was evaluated using the Food and Drug Administration (FDA) and Susceptibility Testing Manufacturers Association (STMA) guidance. Results Of the 105 P. aeruginosa included, 46% had a mucoid phenotype. ETEST MICs typically read 0–1 dilution higher than BMD for all drugs. Categorical agreement and essential agreement ranged from 64 to 93% and 63 to 86%, respectively. The majority of observed errors were minor. A single very major error occurred with ceftazidime (4.2%). For ceftazidime–vibactam, 2 very major errors were observed and both were within essential agreement. Major errors occurred for aztreonam (3.3%), cefepime (9.4%), ceftazidime–avibactam (5.3%, adjusted 2.1%), ceftolozane–tazobactam (1%), meropenem (3.3%), piperacillin–tazobactam (2.9%), and tobramycin (1.5%). Conclusions ETEST methods performed conservatively for most antibiotics against this challenging collection of P. aeruginosa from patients with CF.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S582-S583
Author(s):  
Eleni Karantoni ◽  
Yiqi Su ◽  
Anat Stern ◽  
Phaedon D Zavras ◽  
Sergio Giralt ◽  
...  

Abstract Background The epidemiology of CMV end-organ disease (EOD) after Hematopoietic Cell Transplant (HCT) in the era of preemptive therapy (PET) is defined. In contrast, less data exists on refractory and/or resistant (R/R) CMV. We report on 1) the incidence; 2) risk factors and outcomes of R/R CMV by 1-year post HCT. Methods Retrospective review of 167 CMV seropositive (R+) recipients of first marrow or peripheral blood HCT from 1/2014 - 12/2017 managed by PET. Refractory CMV was defined as failure to achieve >1 log10 decrease in CMV viral load (VL) and having VL >1,000 IU/mL after ≥14 day of PET. Resistant CMV required genotypic confirmation of resistance mutation(s) in UL54 and/or UL97 genes. End organ disease (EOD) was defined by standard criteria. Patients (pts) were followed through 1-year post HCT and were categorized in two mutually exclusive groups as R/R and no R/R. Demographics, clinical characteristics and outcomes were extracted from medical records and hospital databases. Univariable and multivariable logistic models were used to identify risk factors for R/R CMV. Results Of 167 PET recipients, 91 (54.5%) received ex vivo T cell depleted (TCD) HCT; 40 (24.0%) had mismatched donor; and 26 (15.6%) had multiple myeloma. 66/167 (39.5%) pts developed refractory CMV (6 pts also had resistant CMV). Time from HCT to CMV viremia was shorter in R/R group: median (IQR) 21.5 (17.2-27.8) days compared to no R/R group: 26 (19-32) days (p=0.031). Maximum VL was higher for R/R compared to no R/R: median (IQR) 9,118 (2,849-18,456) and 868 (474-1,908), respectively (p< 0.001). In multivariable model, risk factors for R/R included TCD HCT (p< 0.0001) and higher VL at PET initiation (p=0.0002). In contrast, CMV seropositive donor (p=0.035) was protective (Figure 1). CMV EOD developed in 28.2% of R/R and 16.2% of no R/R groups (p=0.085) (Figure 2). Overall survival at 1 year was 59.1% for R/R compared to 83.1% for no R/R group (p=0.00027) (Figure 3). Figure 1. Adjusted odds ratio (OR) and 95% confidence interval (CI) from multivariable model evaluating risk factors of refractory/resistant (R/R) CMV. Figure 2. Cumulative incidence curves of CMV end-organ disease (EOD) at 1-year post HCT Figure 3. Kaplan-Meier survival curves of overall survival (OS) at 1-year post HCT Conclusion 1) Refractory and/or resistant CMV occurred in 39,5% of PET recipients. 2) T-cell depletion and higher CMV VL at PET initiation were risk factors for R/R CMV in multivariable models. 3) R/R CMV was associated with more EOD and worse overall survival. Disclosures Sergio Giralt, MD, Amgen (Advisor or Review Panel member, Research Grant or Support, Served an advisory board for Amgen, Actinuum, Celgene, Johnson & Johnson, JAZZ pharmaceutical, Takeda, Novartis, KITE, and Spectrum pharma and has received research support from Amgen, Actinuum, Celgene, Johnson & Johnson, and Miltenyi, Takeda.) Miguel-Angel Perales, MD, Abbvie (Other Financial or Material Support, Honoraria from Abbvie, Bellicum, Celgene, Bristol-Myers Squibb, Incyte, Merck, Novartis, Nektar Therapeutics, Omeros, and Takeda.)ASTCT (Other Financial or Material Support, Volunteer member of the Board of Directors of American Society for Transplantation and Cellular Therapy (ASTCT), Be The Match (National Marrow Donor Program, NMDP), and the CIBMTR Cellular Immunotherapy Data Resource (CIDR) Committee)Cidara Therapeutics (Advisor or Review Panel member, Other Financial or Material Support, Serve on DSMBs for Cidara Therapeutics, Servier and Medigene, and the scientific advisory boards of MolMed and NexImmune.)Kite/Gilead (Research Grant or Support, Other Financial or Material Support, Received research support for clinical trials from Incyte, Kite/Gilead and Miltenyi Biotec.) Genovefa Papanicolaou, MD, Chimerix (Research Grant or Support)Merck&Co (Research Grant or Support, Investigator and received funding and consulting fees from Merck, Chimerix, Shire and Astellas)


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S733-S733
Author(s):  
Dee Shorttidge ◽  
Jennifer M Streit ◽  
Michael D Huband ◽  
Robert K Flamm

Abstract Background Delafloxacin (DLX) is an anionic fluoroquinolone (FQ) that has been approved in the United States and in Europe for the treatment of acute bacterial skin and skin structure infections and was recently approved in the US for treatment of community-acquired bacterial pneumonia (CABP). In the present study, in vitro susceptibility (S) results for DLX and comparator agents were determined for CABP pathogens including Streptococcus pneumoniae (SPN), Haemophilus influenzae (HI), H. parainfluenzae (HP) and Moraxella catarrhalis (MC) clinical isolates from European hospitals participating in the SENTRY Program during 2014-2019. Methods A total of 2,835 SPN, 1,484 HI, 959 MC, and 20 HP isolates were collected from community-acquired respiratory tract infections (CARTI) during 2014-2019 from European hospitals. Sites included only 1 isolate/patient/infection episode. Isolate identifications were confirmed at JMI Laboratories. Susceptibility testing was performed according to CLSI broth microdilution methodology, and EUCAST (2020) breakpoints were applied where applicable. Other antimicrobials tested included levofloxacin (LEV) and moxifloxacin (MOX; not tested in 2015). Multidrug-resistant (MDR) SPN isolates were categorized as being nonsusceptible (NS) to amoxicillin-clavulanate, erythromycin (ERY), and tetracycline; other SPN phenotypes were ERY-NS, or penicillin (PEN)-NS. β-lactamase (BL) presence was determined for HI, HP, and MC. Results The activities of the 3 FQs are shown in the table. The most active agent against SPN was DLX, with the lowest MIC50/90 values of 0.015/0.03 mg/L. DLX activities were the same when tested against the MDR or PEN-NS for SPN phenotypes. ERY-NS isolates had DLX MIC50/90 results of 0.015/0.03 mg/L. DLX was the most active FQ against HI, HP, and MC. BL presence did not affect FQ MIC values for HI or MC; only 1 HP isolate was BL-positive. Conclusion DLX demonstrated potent in vitro antibacterial activity against SPN, HI, HP, and MC. DLX was active against MDR SPN that were NS to the agents commonly used as treatments for CABP. These data support the utility of DLX in CABP including when caused by antibiotic resistant strains. Table 1 Disclosures Jennifer M. Streit, BS, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Allergan (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)Merck (Research Grant or Support)Paratek Pharma, LLC (Research Grant or Support) Robert K. Flamm, PhD, A. Menarini Industrie Farmaceutiche Riunite S.R.L. (Research Grant or Support)Amplyx Pharmaceuticals (Research Grant or Support)Basilea Pharmaceutica International, Ltd (Research Grant or Support)Department of Health and Human Services (Research Grant or Support)Melinta Therapeutics, Inc. (Research Grant or Support)


2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S421-S422 ◽  
Author(s):  
Kenneth V I Rolston ◽  
Bahgat Gerges ◽  
Issam Raad ◽  
Samuel L Aitken ◽  
Ruth Reitzel ◽  
...  

Abstract Background Gram-negative bacilli (GNB) are now the predominant cause of bacterial infection in cancer patients (CP). Many GNB are problematic because they have become resistant to commonly used antibiotics. Cefiderocol (CFDC), a novel siderophore cephalosporin, is active against a wide spectrum of GNB. We evaluated its in vitro activity and that of eleven comparator agents against GNB isolated from CP. Methods A total of 341 recent GNB blood isolates from CP were tested using CLSI approved methods for MIC determination by broth microdilution. Comparator agents were amikacin (A), aztreonam (AZ), ceftazidime (CZ), ceftazidime/avibactam (CAV), cefepime (CEF), ciprofloxacin (CIP), colistin (CL), meropenem (MR), ceftolozane/tazobactam (C/T), tigecycline (TG), and trimethoprim/sulfamethoxazole (T/S). Results CFDC MIC90s as mg/L were: S. maltophilia [50 isolates] 0.25, E. coli (ESBL−) [50 isolates] 0.5, E. coli (ESBL+) [51 isolates] 2.0, K. pneumoniae (ESBL− and +) [60 isolates] 0.5; K. pneumoniae (CRE) [22 isolates] 2.0; P. aeruginosa (MDR) [32 isolates] 1.0; E. cloacae [27 isolates] 4.0; Achromobacter spp. [15 isolates] 0.12. CFDC inhibited P. agglomerans, Burkholderia spp., Sphingomonas spp., Ochrobactrum spp. at ≤1 mg/L [23 total isolates] and Elizabethkingia spp. and R. radiobacter at ≤8 mg/L [11 total isolates]. Among comparator agents, only T/S had consistent activity against S. maltophilia. For E. coli (ESBL− and +) MR, TG, CAV, CL were most active. For K. pneumoniae (ESBL–and +) MR, CAV were most active. For K. pneumoniae (CRE) and P. aeruginosa (MDR), none of the comparators had significant activity. For E. cloacae, MR, A, CAV, TG were most active. Among the uncommon organisms, MR and TG had the greatest activity. Conclusion Although susceptibility breakpoints have yet to be determined, CFDC has significant activity (≤4 mg/L) against most problematic Gram-negative organisms causing infections in CP based on available pharmacokinetic/pharmacodynamic data. In particular, its activity against S. maltophilia was superior to the comparators. Also, it was the most active agent against P. aeruginosa (MDR) and K. pneumoniae (CRE). Based on our results, CFDC warrants clinical evaluation for the treatment of blood stream infections caused by GNB in CP. Disclosures K. V. I. Rolston, Merck: Investigator, Research grant; JMI Laboratories: Investigator, Research grant; Shionogi (Japan): Investigator, Research grant. B. Gerges, Shionogi: Collaborator, Research support. S. L. Aitken, Shionogi: Scientific Advisor, Consulting fee; Merck: Scientific Advisor, Consulting fee; Medicines Co: Scientific Advisor, Consulting fee; Achaogen: Scientific Advisor, Consulting fee; Zavante: Scientific Advisor, Consulting fee; R. Prince, Shionogi: Investigator, Research support. Merck: Investigator, Research support.


2021 ◽  
Vol 12 (1) ◽  
pp. 16-26
Author(s):  
Kimberly To ◽  
Ruoqiong Cao ◽  
Aram Yegiazaryan ◽  
James Owens ◽  
Kayvan Sasaninia ◽  
...  

Abstract Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tb) still remains a devastating infectious disease in the world. There has been a daunting increase in the incidence of Type 2 Diabetes Mellitus (T2DM) worldwide. T2DM patients are three times more vulnerable to M. tb infection compared to healthy individuals. TB-T2DM coincidence is a challenge for global health control. Despite some progress in the research, M. tb still has unexplored characteristics in successfully evading host defenses. The lengthy duration of treatment, the emergence of multi-drug-resistant strains and extensive-drug-resistant strains of M. tb have made TB treatment very challenging. Previously, we have tested the antimycobacterial effects of everolimus within in vitro granulomas generated from immune cells derived from peripheral blood of healthy subjects. However, the effectiveness of everolimus treatment against mycobacterial infection in individuals with T2DM is unknown. Furthermore, the effectiveness of the combination of in vivo glutathione (GSH) supplementation in individuals with T2DM along with in vitro treatment of isolated immune cells with everolimus against mycobacterial infection has never been tested. Therefore, we postulated that liposomal glutathione (L-GSH) and everolimus would offer great hope for developing adjunctive therapy for mycobacterial infection. L-GSH or placebo was administered to T2DM individuals orally for three months. Study subjects’ blood was drawn pre- and post-L-GSH/or placebo supplementation, where Peripheral Blood Mononuclear Cells (PBMCs) were isolated from whole blood to conduct in vitro studies with everolimus. We found that in vitro treatment with everolimus, an mTOR (membrane target of rapamycin) inhibitor, significantly reduced intracellular M. bovis BCG infection alone and in conjunction with L-GSH supplementation. Furthermore, we found L-GSH supplementation coupled with in vitro everolimus treatment produced a greater effect in inhibiting the growth of intracellular Mycobacterium bovis BCG, than with the everolimus treatment alone. We also demonstrated the functions of L-GSH along with in vitro everolimus treatment in modulating the levels of cytokines such as IFN-γ, TNF-α, and IL-2 and IL-6, in favor of improving control of the mycobacterial infection. In summary, in vitro everolimus-treatment alone and in combination with oral L-GSH supplementation for three months in individuals with T2DM, was able to increase the levels of T-helper type 1 (Th1) cytokines IFN-γ, TNF-α, and IL-2 as well as enhance the abilities of granulomas from individuals with T2DM to improve control of a mycobacterial infection.


2004 ◽  
Vol 57 (6) ◽  
pp. 400-402 ◽  
Author(s):  
KAZUHIKO OTOGURO ◽  
AKI ISHIYAMA ◽  
MIYUKI KOBAYASHI ◽  
HITOMI SEKIGUCHI ◽  
TAKASHI IZUHARA ◽  
...  

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S329-S330
Author(s):  
Lynn El Haddad ◽  
Cynthia P Harb ◽  
Mark Stibich ◽  
Roy F Chemaly ◽  
Roy F Chemaly

Abstract Background Vancomycin-resistant Enterococci (VRE) is a well-known infectious complication among immunocompromised patients, especially hematopoietic cell transplant (HCT) recipients. VRE colonization of the gastrointestinal tract could be associated with VRE bacteremia and worse outcomes in HCT recipients. The use of systemic antibiotics to eradicate VRE colonization is highly discouraged because of the lack of efficacy, the rapid onset of antibiotic resistance, and the disruption of the normal microbiota. Bacteriophages (phages) may constitute a good alternative to antibiotics to eliminate specific pathogens without disrupting the patient’s normal microbiota. Methods Sewage samples were collected from the City of Houston for phages isolation. Samples were centrifuged, filtered and exposed to several targeted VRE host strains. After several amplification, the final filtrate was titrated and checked for the presence of VRE-specific phages. Isolated phages were observed under electron microscopy and were tested against multiple VRE strains isolated from different sources including patients’ stool samples, patients’ room environment, sewage samples, clinical isolates of daptomycin-resistant VRE strains or vancomycin-susceptible Enterococcus faecium (VSEF) and Enterococcus faecalis (VSEf) strains. Results Four VRE-specific phages were isolated from sewage samples (MDA1, MDA2, MDA3, and MDA4). All phages belong to the Caudovirales order. Phage MDA1 belongs to the Podoviridae family, phage MDA2 is a Siphoviridae, whereas MDA3 and MDA4 belong to the Myoviridae family (Figure 1A). All phages were lytic and were able to inhibit at least four VRE strains and only MDA1 had activity against VSEF and MDA4 against VSEf. The efficacy of these lytic phages complemented one another as the combination of these four phages inhibited all different VRE strains (Figure 1B). Conclusion Our results highlight the feasibility and the potential success of these phages in inhibiting VRE in vitro. These VRE-specific phage cocktails may be used in future studies to reduce VRE colonization and subsequent infections in HCT recipients. Disclosures Roy F. Chemaly, MD, MPH, FACP, FIDSA, Chimerix: Advisory Board, Research Grant; Clinigen: Advisory Board; Merck: Advisory Board, Consultant, Grant/Research Support, Research Grant, Speaker’s Bureau; Oxford immunotec: Consultant, Grant/Research Support; Shire: Research Grant, Speaker’s Bureau; Viracor: Grant/Research Support.


2017 ◽  
Vol 61 (3) ◽  
Author(s):  
D. J. Farrell ◽  
H. S. Sader ◽  
P. R. Rhomberg ◽  
N. E. Scangarella-Oman ◽  
R. K. Flamm

ABSTRACT Gepotidacin (formerly GSK2140944) is a novel, first-in-class, triazaacenaphthylene antibacterial that inhibits bacterial DNA gyrase and topoisomerase IV via a unique mechanism and has demonstrated in vitro activity against Neisseria gonorrhoeae, including drug-resistant strains, and also targets pathogens associated with other conventional and biothreat infections. Broth microdilution was used to evaluate the MIC and minimum bactericidal concentration (MBC) activity of gepotidacin and comparators against 25 N. gonorrhoeae strains (including five ciprofloxacin-nonsusceptible strains). Gepotidacin activity was also evaluated against three N. gonorrhoeae strains (including a ciprofloxacin-nonsusceptible strain) for resistance development, against three N. gonorrhoeae strains (including two tetracycline- and azithromycin-nonsusceptible strains) using time-kill kinetics and checkerboard methods, and against two N. gonorrhoeae strains for the investigation of postantibiotic (PAE) and subinhibitory (PAE-SME) effects. The MIC50 and MIC90 for gepotidacin against the 25 N. gonorrhoeae isolates tested were 0.12 and 0.25 μg/ml, respectively. The MBC50 and MBC90 for gepotidacin were 0.25 and 0.5 μg/ml, respectively. Gepotidacin was bactericidal, and single-step resistance selection studies did not recover any mutants, indicating a low rate of spontaneous single-step resistance. For combinations of gepotidacin and comparators tested using checkerboard methods, there were no instances where antagonism occurred and only one instance of synergy (with moxifloxacin; fractional inhibitory concentration, 0.375). This was not confirmed by in vitro time-kill studies. The PAE for gepotidacin against the wild-type strain ranged from 0.5 to >2.5 h, and the PAE-SME was >2.5 h. These in vitro data indicate that further study of gepotidacin is warranted for potential use in treating infections caused by N. gonorrhoeae.


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