scholarly journals In vitro Susceptibility Pattern of Major Gram Negative Isolates to Selected Antimicrobial Agents

2019 ◽  
pp. 1-8
Author(s):  
Shalini Gupta ◽  
Pankaj Mandale
Keyword(s):  
Antimicrobial Susceptibility ◽  
Bacterial Infections ◽  
Therapeutic Option ◽  
Polymyxin B ◽  
Susceptibility Pattern ◽  
In Vitro Susceptibility ◽  
Gram Negative ◽  
E Coli ◽  
Susceptibility Data

Background: The choice of choosing right anti-microbial therapy in hospitals depends on the knowledge of local anti-microbial susceptibility profile. This retrospective study was conducted to assess the in vitro susceptibility pattern of different pathogen isolates to various antibiotics including Cefepime-Amikacin-Antibiotic resistant breakers (ARBs)* in various hospitals across the Jaipur City. Methods: To characterize the antimicrobial susceptibility pattern of different isolates from various hospitals across the Jaipur City, a retrospective, observational analysis was done for antibiogram data. A total of 1201 Gram negative isolates collected during the period from January 2017 to December 2017 were included in the study. Antibiotic sensitivity testing was done in accordance with the recommendations of Clinical Laboratory Standard Institute (CLSI) guidelines. Results: Of the total 1201 Gram negative isolates included in this study, 51.6% were from wounds and pus specimens, 40.1% were from respiratory and 8.2% from blood. P. aeruginosa (49.7%) was the most frequently isolated pathogen distantly followed by A. baumannii (21.6%), K. pneumoniae (16.6%) and E. coli (12.1%). The highest susceptibility was reported to polymyxins (100%) including Colistin and Polymyxin B, among all the tested bacteria’s and system wise. Among all the antibiotic tested, (Cefepime-Amikacin-ARBs*) sensitivity ranged for 87.9% to 52% on pathogens (E. coli, K. pneumonia, P. aeruginosa) tested from samples of skin and soft tissue, respiratory tract, blood stream, followed by Meropenem ranged for 78.4% to 55% on pathogens (E. coli, K. pneumonia, P. aeruginosa), followed by ceftazidime-tazobactam ranged for 82.7% to 58% on pathogens (E. coli, K. pneumonia, P. aeruginosa) and 22.7% sensitive for A. baumannii to Cefoperazone sulbactam. Based on pathogen type, E. coli exhibited highest overall susceptibility and the lowest was reported by A. baumannii. The susceptibility of A. baumannii ranged from 1-26% to all the tested antibiotics except polymyxins with 100% susceptibility. Conclusions: This in vitro susceptibility data suggests that Cefepime-Amikacin-ARBs* can serve as important therapeutic option for the treatment of various resistant Gram-negative bacterial infections to relieve the excess pressure on last resort antibiotics, carbapenems and other drugs including Colistin and polymyxin B. Cefepime-Amikacin-ARBs*on the basis of antimicrobial susceptibility data can be considered as an effective therapeutic option for carbapenems in treating gram negative bacterial infections, and could be considered as a broad spectrum antibiotic sparer’s like carbapenem, colistin and Polymyxin B.

scholarly journals Comparative in vitro Activities of Different Antibiotics against Clinical Isolates of Gram-negative Bacilli

2019 ◽  
pp. 1-8
Author(s):  
Sachin H. Jain ◽  
Pradnya Joshi
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Therapeutic Option ◽  
Critical Role ◽  
Final Analysis ◽  
Klebsiella Species ◽  
In Vitro Susceptibility ◽  
Gram Negative ◽  
E Coli

Objective: The local anti-microbial susceptibility profile plays a very critical role in guiding clinicians to choose the appropriate empiric therapies. This study was conducted to assess the pathogen characteristics and the in vitro susceptibility of different Gram negative isolates to commonly used antibiotics in our hospital settings. Methods: A total of 110 Gram negative isolates were included in the study.  A retrospective, observational analysis of antibiogram data was performed for four antimicrobial agents including CSE-1034 (ceftriaxone-sulbactam-EDTA), piperacillin-tazobactam (pip-taz), cefoperazone-sulbactam and meropenem.  Results: Of the 200 clinical specimens analysed, Gram negative isolates obtained from 110 samples were included in the final analysis. The most common Gram negative isolates were Klebsiella species (35.5%), E. coli (33.6%) and P. aeruginosa (21.8%). The overall susceptibility was highest to CSE-1034 (100%) followed by meropenem (66.4%), cefoperazone-sulbactam (56.4%) and pip-taz (45.5%). The MIC90 range of CSE-1034 for Enterobacteriaceae was ≤0.5-≤4μg/ml and ≤2μg/ml for susceptible P. aeruginosa isolates. The MIC90 of meropenem for 94.4% of meropenem-susceptible Enterobacteriaceae strains was <0.25μg/ml and 64.3% of P. aeruginosa were having MIC ≤0.25μg/ml. The MIC90 of pip-taz for 82.5% of the pip-taz susceptible Enterobacteriaceae strains was 4μg/ml and 63.6% of P. aeruginosa was ≤8.0μg/ml. The MIC90 of cefoperazone-sulbactam susceptible strains were between ≤8 to ≤16μg/ml and 45.8% isolates of susceptible P. aeruginosa were having MIC between ≤8 to ≤16μg/ml. Conclusions: Overall, this in vitro surveillance study suggests that CSE-1034 can be considered an important therapeutic option for the treatment of various multi drug resistant Gram-negative bacterial infections and avert the threat of resistance to last resort antibiotics including carbapenems.

Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing Position Statements on Polymyxin B and Colistin Clinical Breakpoints

2020 ◽  
Author(s):  
Michael J Satlin ◽  
James S Lewis ◽  
Melvin P Weinstein ◽  
Jean Patel ◽  
Romney M Humphries ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Polymyxin B ◽  
Antimicrobial Susceptibility Testing ◽  
In Vitro Susceptibility ◽  
Susceptibility Data ◽  
European Committee ◽  
Clinical Breakpoints ◽  
State Concentration

Abstract Recent data on polymyxin pharmacokinetics, pharmacodynamics, toxicity, and clinical outcomes suggest these agents have limited clinical utility. Pharmacokinetics-pharmacodynamics data show a steady-state concentration of 2 μg/mL is required for killing bacteria with colistin minimum inhibitory concentrations of 2 μg/mL. Less than 50% of patients with normal renal function achieve this exposure, and it is associated with high risk of nephrotoxicity. This exposure does not achieve bacterial stasis in pneumonia models. Randomized and observational studies consistently demonstrate increased mortality for polymyxins compared with alternative agents. The Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) are 2 global organizations that establish interpretive criteria for in vitro susceptibility data. CLSI has recently taken the step to eliminate the “susceptible” interpretive category for the polymyxins, whereas EUCAST maintains this interpretive category. This viewpoint describes the opinions of these organizations and the data that were used to inform their perspectives.

scholarly journals 1181. Use of the Combination Antibiogram in the Era of MDR Gram-Negative Pathogens

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S357-S357
Author(s):  
Kenneth Klinker ◽  
Kartikeya Cherabuddi ◽  
Mark Redell ◽  
Matthew Balogh ◽  
Jill Massey ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Empiric Therapy ◽  
Multidrug Resistant ◽  
In Vitro Susceptibility ◽  
University Of Florida ◽  
Gram Negative ◽  
E Coli ◽  
Susceptibility Data ◽  
The University

Abstract Background Combinations of two or more antimicrobial agents are frequently used in empiric therapy regimens to ensure at least one agent demonstrates activity against suspected pathogens. A combination antibiogram can assess the increase in empiric coverage of a particular combination vs. either of the agents alone (i.e., percent gain). These data could assist in developing empiric regimens that may be particularly useful in settings with problematic multidrug-resistant Gram-negative pathogens. Methods An Excel-based model to construct combination antibiograms was developed to assist clinicians in evaluating institutional susceptibility data. The University of Florida Health Shands Hospital microbiology laboratory supplied susceptibility data for ceftriaxone (CFX), cefepime (CEF), ciprofloxacin (CIP), and amikacin (AMI) to assess % gain achieved with combinations for E. coli all blood isolates (n = 206) and blood isolates with an ESBL phenotype (n = 35). The same laboratory provided susceptibility data for CEF, piperacillin–tazobactam (PTZ), AMI and CIP for P. aeruginosa (all, n = 250; carbapenem-resistant (CARB-R), n = 30). Results Percent gains achieved by adding AMI or CIP to CFX and CEF to capture at least one agent exhibiting in vitro susceptibility against all blood E. coli were calculated: CFX-AMI, 16%; CFTX-CIP, 3%; CEF-AMI, 10%; CEF-CIP, 1%. The percentage gain specific to E. coli blood isolates with an ESBL phenotype ranged from 9% to 86%. The combination with the greatest percent loss against blood E. coli isolates, comparing all blood isolates to those with an ESBL phenotype, was CFX-CIP (∆-66%). Percentage gain achieved against all isolates of Pa by adding AMI or CIP to PTZ and CEF were CEF-AMI, 8%; CEF-CIP, 5%; PTZ-AMI, 15%; PTZ-CIP, 9%; percent gain of the same combinations against P. aeruginosa CARB-R isolates were 23%, 10%, 47%, and 30%, respectively. Adding AMI to either β-lactam: PTZ % S increased from 47% to 77% (+CIP) and to 94% (+AMI); CEF % S increased from 60% S to 70% (+CIP) and to 83% (+AMI). Conclusion Combination antibiogram models can assist clinicians in identifying regimens which may provide improved targeting of MDR phenotypes through calculation of percent gain. Disclosures K. Klinker, Melinta Therapeutics: Consultant, Speaker honorarium. Nabriva Therapeutics: Scientific Advisor, Consulting fee. M. Redell, Melinta Therapeutics, Inc.: Employee and Shareholder, Salary. M. Balogh, Melinta Therapeutics, Inc.: Employee and Shareholder, Salary. J. Massey, Melinta Therapeutics, Inc.: Employee and Shareholder, Salary. M. Dudley, The Medicines Company: Employee, Salary.

scholarly journals In vitro antimicrobial susceptibility of clinical respiratory isolates to ceftazidime-avibactam and comparators (2016–2018)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
D. Piérard ◽  
G. G. Stone
Keyword(s):  
Antimicrobial Susceptibility ◽  
Multidrug Resistant ◽  
Dosing Regimen ◽  
Gram Negative ◽  
E Coli ◽  
Susceptibility Data ◽  
Antimicrobial Surveillance ◽  
Genes Encoding ◽  
Respiratory Specimens

Abstract Background This antimicrobial surveillance study reports in vitro antimicrobial activity and susceptibility data for a panel of agents against respiratory isolates of Enterobacterales and Pseudomonas aeruginosa. Methods Isolates from respiratory specimens were collected in Africa/Middle East, Asia/South Pacific, Europe and Latin America between 2016 and 2018, as part of the Antimicrobial Testing Leadership and Surveillance (ATLAS) program. Broth microdilution methodology was used to quantify minimum inhibitory concentrations, from which rates of susceptibility were determined using EUCAST breakpoints (version 10). Rates of subsets with genes encoding β-lactamases (extended-spectrum β-lactamases [ESBLs], serine carbapenemases and metallo-β-lactamases [MBLs]) were also determined, as well as rates of multidrug-resistant (MDR) P. aeruginosa. Results Among all respiratory Enterobacterales isolates, susceptibility to ceftazidime-avibactam, meropenem, colistin and amikacin was ≥94.4% in each region. For Enterobacterales isolates that were ESBL-positive or carbapenemase-positive/MBL-negative, ceftazidime-avibactam susceptibility was 93.6 and 98.9%, respectively. Fewer than 42.7% of MBL-positive Enterobacterales isolates were susceptible to any agents, except colistin (89.0% susceptible). Tigecycline susceptibility was ≥90.0% among Citrobacter koseri and Escherichia coli isolates, including all β-lactamase-positive subsets. ESBL-positive Enterobacterales were more commonly identified in each region than isolates that were ESBL/carbapenemase-positive; carbapenemase-positive/MBL-negative; or MBL-positive. Among all respiratory P. aeruginosa isolates, the combined susceptibility rates (susceptible at standard dosing regimen plus susceptible at increased exposure) were highest to ceftazidime-avibactam, colistin and amikacin (≥82.4% in each region). Susceptibility to colistin was ≥98.1% for all β-lactamase-positive subsets of P. aeruginosa. The lowest rates of antimicrobial susceptibility were observed among MBL-positive isolates of P. aeruginosa (≤56.6%), with the exception of colistin (100% susceptible). MDR P. aeruginosa were most frequently identified in each region (18.7–28.7%), compared with the subsets of ESBL-positive; carbapenemase-positive/MBL-negative; or MBL-positive isolates. Conclusions Rates of susceptibility among the collections of respiratory Enterobacterales and P. aeruginosa isolates were highest to ceftazidime-avibactam, colistin and amikacin in each region. Tigecycline was active against all subsets of C. koseri and E. coli, and colistin was active against all subsets of P. aeruginosa. The findings of this study indicate the need for continued antimicrobial surveillance among respiratory Gram-negative pathogens, in particular those with genes encoding MBLs.

scholarly journals 2214. Comparison of Cefepime–Zidebactam (WCK 5222), Ceftazidime–Avibactam, and Ceftolozane–Tazobactam Tested Against Gram-Negative Organisms Causing Pneumonia in United States Hospitals in 2018

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S755-S755 ◽  
Author(s):  
Helio S Sader ◽  
Cecilia G Carvalhaes ◽  
Rodrigo E Mendes ◽  
Mariana Castanheira ◽  
Robert K Flamm
Keyword(s):  
Therapeutic Option ◽  
High Dose ◽  
Gram Negative ◽  
E Coli ◽  
Highly Active ◽  
Medical Centers ◽  
Carbapenem Resistant ◽  
Gram Negative Organisms ◽  
Dual Mechanism

Abstract Background Zidebactam (ZID) is a bicyclo-acyl hydrazide antibiotic with a dual mechanism of action: selective Gram-negative PBP2 binding and β-lactamase inhibition. We evaluated the frequency and antimicrobial susceptibility (S) of Gram-negative bacilli (GNB) isolated from patients with pneumonia in US hospitals. Methods All 3,086 clinical isolates were consecutively collected from patients hospitalized with pneumonia (1/patient) in 29 US medical centers in 2018, and the GNB (n = 2,171) were S tested against cefepime (FEP)-ZID (1:1 ratio) and comparators by reference broth microdilution methods. The FEP S breakpoint of ≤8 mg/L (CLSI, high dose) was applied to FEP-ZID for comparison purposes. An FEP-ZID S breakpoint of ≤64 mg/L has been proposed for non-fermentative GNB based on pharmacokinetic/pharmacodynamic target attainment and was applied. Enterobacterales (ENT) isolateswere screened for β-lactamase genes by whole-genome sequencing. Results GNB represented 70.3% of the collection, and the most common GNB were P. aeruginosa (PSA; 34.9% of GNB), K. pneumoniae (10.9%), E. coli (9.7%), S. marcescens (7.7%), and S. maltophilia (XM; 6.4%). FEP-ZID was highly active against PSA (MIC50/90, 2/8 mg/L; 98.8% and 99.9% inhibited at ≤8 and ≤16 mg/L, respectively; highest MIC, 32 mg/L), including resistant subsets (table). Among comparators, colistin (99.6%S), ceftazidime–avibactam (CAZ-AVI; 95.2%S), and ceftolozane–tazobactam (C-T; 94.5%S) were the most active compounds against PSA. FEP-ZID inhibited all ENT at ≤4 mg/L, including ESBL-producers (MIC90, 0.25 mg/L) and carbapenem-resistant ENT (MIC90, 4 mg/L). The most active comparators against ENT were CAZ-AVI (99.9%S), amikacin (98.5%S), and meropenem (MEM; 98.3%S). FEP-ZID inhibited 75.0% and 97.9% of XM isolates at ≤8 and ≤16 mg/L, respectively (highest MIC, 64 mg/L). The only other compounds active against XM were co-trimoxazole (MIC50/90, ≤0.12/2 mg/L; 95.7%S) and levofloxacin (MIC50/90, 1/2 mg/L; 70.7%S). FEP-ZID inhibited 71.0% and 98.9% of A. baumannii isolates at ≤8 and ≤64 mg/L,, respectively. Conclusion FEP-ZID showed potent in vitro activity against GNB causing pneumonia in US hospitals and may represent a valuable therapeutic option for these difficult-to-treat infections Disclosures All authors: No reported disclosures.

scholarly journals In vitro and in vivo antibacterial efficacies of CFC-222, a new fluoroquinolone.

1997 ◽  
Vol 41 (10) ◽  
pp. 2209-2213 ◽  
Author(s):  
J H Kim ◽  
J A Kang ◽  
Y G Kim ◽  
J W Kim ◽  
J H Lee ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Protective Efficacy ◽  
Horse Serum ◽  
The Other ◽  
Infection Model ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli

CFC-222 is a novel fluoroquinolone containing a C-7 bicyclic amine moiety with potent antibacterial activities against gram-positive, gram-negative, and anaerobic organisms. We compared the in vitro and in vivo activities of CFC-222 with those of ciprofloxacin, ofloxacin, and lomefloxacin. CFC-222 was more active than the other fluoroquinolones tested against gram-positive bacteria. CFC-222 was particularly active against Streptococcus pneumoniae (MIC at which 90% of isolates are inhibited [MIC90], 0.2 microg/ml), Staphylococcus aureus (MIC90, 0.2 microg/ml for ciprofloxacin-susceptible strains), and Enterococcus faecalis (MIC90, 0.39 microg/ml). Against Escherichia coli and other members of the family Enterobacteriaceae, CFC-222 was slightly less active than ciprofloxacin (MIC90s for E. coli, 0.1 and 0.025 microg/ml, respectively). The in vitro activity of CFC-222 was not influenced by inoculum size, medium composition, or the presence of horse serum. However, its activity was decreased significantly by a change in the pH of the medium from 7.0 to 6.0, as was the case for the other quinolones tested. The in vivo protective efficacy of CFC-222 by oral administration was greater than those of the other quinolones tested in a mouse model of intraperitoneally inoculated systemic infection caused by S. aureus. CFC-222 exhibited efficacy comparable to that of ciprofloxacin in the same model of infection caused by gram-negative organisms, such as E. coli and Klebsiella pneumoniae. In this infection model, CFC-222 was slightly less active than ciprofloxacin against Pseudomonas aeruginosa. These results suggest that CFC-222 may be a promising therapeutic agent in various bacterial infections.

scholarly journals Characterization and in vitro susceptibility profile of bacterial samples harvest from canine chronic otitis

2021 ◽  
Vol 15 (2) ◽  
pp. 110-118
Author(s):  
Jorge Bárcena Barriuso ◽  
Deivid Roni Ribeiro ◽  
Javier Felipe Burchard ◽  
Kung Darh Chi ◽  
Amanda Anater ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Metropolitan Region ◽  
In Vitro Susceptibility ◽  
Susceptibility Data ◽  
Positive Bacterial Culture ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests ◽  
Staphylococcus Spp ◽  
Veterinary Hospital

This study aimed to identify which are the most frequent bacteria evolved in cases of chronic otitis in dogs in the metropolitan region of Curitiba, as well to determine their in vitro antimicrobial susceptibility. Data of positive bacterial culture from dogs affected by chronic or recurrent otitis were compiled from the records of the veterinary hospital of Pontifícia Universidade Católica do Paraná, Curitiba, southern Brazil. In a period of 16 months, a total of 83 bacterial cultures were performed, resulting in 192 isolates. All isolates were submitted to antimicrobial susceptibility tests, based on the Kirby-Bauer technique using 17 drugs from 8 antibiotic classes (?-lactams, aminoglycosides, lincosamides, macrolides, polypeptides, quinolones, tetracyclines, and amphenicols). The five most frequent bacterial isolates were Staphylococcus spp. (58.32%), Proteus spp. (14.58%), Escherichia coli (9.90%) and Pseudomonas spp. (8.33%). The four most effective antibiotics were amikacin (13.29%), neomycin (24.47%), gentamicin (25.52%) and tobramycin (26.70%); however, these aminoglycosides may cause ototoxicity, and their use should be restricted when the tympanic membrane is intact. Quinolones also showed antimicrobial effectiveness, with 29.17% of the isolates showing resistance to ciprofloxacin and 29.69% to enrofloxacin. According to the results, it can be concluded that aminoglycosides and quinolones were effective against microorganisms of canine chronic otitis.

scholarly journals Comparative study of in vitro activities of polymyxin B commercial products on Pseudomonas aeruginosa isolated from hospitalized patients

2021 ◽  
Vol 62 (3) ◽  
pp. 270-279
Author(s):  
Rezvan Goodarzi ◽  
Farhad Farahani ◽  
Mahdane Roshani ◽  
Mohammad Taheri ◽  
Babak Asghari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Susceptibility Testing ◽  
Renal Toxicity ◽  
Polymyxin B ◽  
Microbiological Activity ◽  
Commercial Products ◽  
Gram Negative ◽  
In Vitro Antibacterial Activity

Introduction: Polymyxin B has been applied as one of the last-resort antibiotics for the treatment of multidrug resistance among Gram-negative bacterial infections. Due to side effects such as renal toxicity, the use of polymyxin is associated with limitations. The present study evaluates in vitro antibacterial activity of a number of polymyxin B commercial products against Pseudomonas aeruginosa. Methods: This study included 63 non-duplicated P. aeruginosa isolates examined for in vitro polymyxin B susceptibility testing using the following powder disks: polymyxin B sulfate, otosporin, Poly-Mxb, and Myxacort. MIC50 and MIC90 have also been identified for polymyxin B antibiotics. Results: Myxacort had functional activity against most P. aeruginosa isolates, and only seven isolates had a relatively high MIC. The activities of Poly-MXb and Myxacort were the same as otosporin. Conclusions: Our findings revealed that the national generic polymyxin B product (Myxacort), and two external products (Otosporin, Poly-MXb) are similar in terms of microbiological activity.

scholarly journals Determination of Extended-Spectrum β-Lactamases and AmpC Production in Uropathogenic Isolates of Escherichia coli and Susceptibility to Fosfomycin

2013 ◽  
Vol 5 (02) ◽  
pp. 090-093 ◽  
Author(s):  
Varsha Gupta ◽  
Hena Rani ◽  
Nidhi Singla ◽  
Neelam Kaistha ◽  
Jagdish Chander
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Susceptibility ◽  
Boronic Acid ◽  
Treatment Options ◽  
Community Setting ◽  
Integrated Approach ◽  
Susceptibility Pattern ◽  
E Coli ◽  
Antimicrobial Susceptibility Pattern

ABSTRACT Background: Urinary tract infection due to Escherichia coli is one of the common problem in clinical practice. Various drug resistance mechanisms are making the bacteria resistant to higher group of drugs making the treatment options very limited. This study was undertaken to detect ESBLs and AmpC production in uropathogenic Escherichia coli isolates and to determine their antimicrobial susceptibility pattern with special reference to fosfomycin. Materials and Methods: A total number of 150 E. coli isolates were studied. ESBL detection was done by double disc synergy and CLSI method. AmpC screening was done using cefoxitin disc and confirmation was done using cefoxitin/cefoxitin-boronic acid discs. In AmpC positive isolates, ESBLs was detected by modifying CLSI method using boronic acid. Antimicrobial susceptibility pattern was determined following CLSI guidelines. Fosfomycin susceptibility was determined by disc diffusion and E-test methods. Results: ESBLs production was seen in 52.6% of isolates and AmpC production was seen in 8% of isolates. All AmpC producers were also found to be ESBLs positive. ESBLs positive isolates were found to be more drug resistant than ESBLs negative isolates. All the strains were found to be fosfomycin sensitive. Conclusions: ESBLs and AmpC producing isolates are becoming prevalent in E. coli isolates from community setting also. Amongst the oral drugs, no in-vitro resistance has been seen for fosfomycin making it a newer choice of drug (although not new) in future. An integrated approach to contain antimicrobial resistance should be actually the goal of present times.

scholarly journals 616. Evaluation of In Vitro Susceptibility to Ceftazidime/Avibactam of Clinical Isolates of Carbapenem Nonsusceptible Gram-Negative Bacilli from Colombia

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S287-S287
Author(s):  
Tobias M Appel ◽  
Maria F Mojica ◽  
Elsa De La Cadena ◽  
Christian Pallares ◽  
Maria Virginia Villegas
Keyword(s):  
Therapeutic Option ◽  
Generation Cephalosporin ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
In Vitro Susceptibility ◽  
Gram Negative ◽  
Fixed Concentration ◽  
Class B

Abstract Background Ceftazidime/avibactam (CZA) is a combination of a third-generation cephalosporin and a diazabicyclooctane β-lactamase inhibitor, which is active against a broad range of class A, C and D β-lactamases. In Colombia, high rates of multidrug-resistant Enterobacteriaceae (Ent)and P. aeruginosa (Pae) have been reported. Of special concern are KPC enzymes endemic in Ent and found in Pae, which are associated with higher mortality and healthcare costs, as well as limited therapeutic options. Herein, we evaluate the susceptibility of clinical isolates of carbapenem nonsusceptible Ent (CNS-E) and Pae (CNS-P) to CZA with the aim of understanding its role as a therapeutic option for these bacteria. Methods Three hundred ninety-nine nonduplicate clinical isolates of carbapenem nonsusceptible Gram-negative bacilli were collected in 13 medical centers from 12 Colombian cities, from January 2016 to October 2017 (137 K. pneumoniae [Kpn], 76 E. coli, 34 Enterobacter spp., 21 S. marcescens [Sma] and 131 Pae). CNS-E was defined as minimum inhibitory concentrations (MIC) ≥1 mg/L for ertapenem and CNS-P was defined as MIC ≥4 mg/L for meropenem. MIC were determined by broth microdilution and interpreted according to current CLSI guidelines. CZA MIC were determined using double dilutions of ceftazidime and a fixed concentration of avibactam of 4 mg/L. Comparator agents were ceftazidime, cefepime, piperacillin/tazobactam, imipenem, meropenem, tigecycline (TGC), and fosfomycin (FOS). Results Antimicrobial activity of CZA and comparators is shown in Table 1. CZA susceptibility ranged from 69% in Kpn to 81% in Sma, whereas 49% of CNS-P were susceptible to CZA. In both, CNS-E and CNS-P, CZA was superior to all other tested β-lactam compounds. Notably, in CNS-E CZA susceptibility was comparable to FOS and TGC (except for TGC in Sma). Conclusion CZA is the most active β-lactam against CNS-E and CNS-P. CZA nonsusceptibility suggests the presence of other resistance mechanisms, such as class B β-lactamases that are not inhibited by avibactam, and which are more frequently reported in CNS-P. Our results highlight the key role of new agents such as CZA in KPC endemic countries and the need for surveillance studies to determine the nature of resistance mechanisms. Disclosures All authors: No reported disclosures.

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