Synergy testing of multidrug resistant Acinetobacter baumanii against tigecycline and polymyxin using an E-test methodology

Objectives - Surgical site infections (SSI) has turn out to be a major problem even in hospital with most modern facilities and standard protocols of pre -operative preparation and antibiotic prophylaxis. Objective of this study is to know the prevalence of surgical site infection among the postoperative patients and to identify the relationship between SSI and etiological pathogens along with their antimicrobial susceptibility at North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGRIHMS), Shillong. Methods - A retrospective case study conducted at NEIGRIHMS, among patients admitted to the surgical departments during the period between January 1st and December 31st 2016. Swabs from the surgical sites were collected under sterile conditions and standard bacteriological tests were performed for identification and appropriate statistical methods were employed to look for association between SSI and etiological pathogens. Results - Out of the 1284 samples included in the study, 192 samples showed evidence of SSI yielding an infection rate of 14.9%. The most commonly isolated bacteria were: Escherichia coli, Acinetobacter baumanii and Staphylococcus aureus, of the gram negative isolates 6.2% were multidrug resistant of which 19% were carbapenem resistant. Conclusion - SSI with multiple drug resistance strains and polymicrobial etiology reflects therapeutic failure. The outcome of the SSI surveillance in our hospital revealed that in order to decrease the incidence of SSI we would have to: a) incorporate a proper antibiotic stewardship b) conduct periodic surveillance to keep a check on SSI d) educate medical staffs regarding the prevention of surgical site infection.

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1597. Ceftolozane-Tazobactam and Meropenem Synergy Testing Against Multi-Drug and Extensively-Drug Resistant Pseudomonas aeruginosa

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1777 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S794-S795

Author(s):

Mary Francine P Chua ◽

Syeda Sara Nida ◽

Jerry Lawhorn ◽

Janak Koirala

Keyword(s):

Pseudomonas Aeruginosa ◽

Synergistic Effect ◽

Inhibitory Concentration ◽

Multidrug Resistant ◽

Additive Effect ◽

Teaching Hospitals ◽

Drug Resistant ◽

Extensively Drug Resistant ◽

Synergy Testing ◽

Concentration Indices

Abstract Background Multidrug-resistant (MDR) and extensively drug-resistant (XDR) Pseudomonas aeruginosa (PA) have limited therapeutic options for treatment. Ceftolozane/tazobactam is a newer anti-pseudomonal drug effective against resistant PA infections, however resistance against this drug has now also developed and is increasing. In this study, we explored the combination of ceftolozane/tazobactam (CT) and meropenem (MP) as a possible effective regimen against MDR and XDR PA. Methods We obtained 33 non-duplicate isolates of MDR and XDR PA grown from blood, urine and respiratory samples collected from patients admitted between 2015 and 2019 at our two affiliate teaching hospitals. MDR PA was defined as resistance to 3 or more classes of anti-pseudomonal antibiotics, and XDR PA as resistance to all but two or less classes of anti-pseudomonal antibiotics. Antimicrobial preparations of both MP and CT were made according to manufacturer instructions. Susceptibility testing was performed using the checkerboard method in accordance to CLSI guidelines (CLSI M100, 2017). The ATCC 27853 strain of PA used as control. Synergy, additive effect, indifference and antagonism were defined as FIC (fractional inhibitory concentration) indices of ≤0.5, >0.5 to <1, >1 to <4, and >4, respectively. Results Thirteen (39%) of 33 PA isolates were classified as XDR, while 20 (61%) PA isolates were MDR. All isolates were resistant to MP (MIC50 >32 ug/mL), while only 2 (6%) isolates were susceptible to CT (MIC50 64 ug/mL). A synergistic effect was seen in 9 (27.3%) of PA isolates (FIC index range 0.28 to 0.5)— 2 of which were XDR PA, and 7 were MDR PA. An additive effect was seen in 12 (36.4%), with indifference seen in 12 (36.4%) of isolates. In this study, no antagonism was seen when CT and MP were combined. Conclusion When used in combination, CT and MP can exert a synergistic effect against MDR and XDR PA. Additive effect and indifference can also be seen when both antibiotics were used. Moreover, there was no antagonism seen when both antibiotics were combined. This study shows that the use of CT and MP in combination may be an option against XDR and MDR PA infections. Disclosures All Authors: No reported disclosures

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Antimicrobial Activity of Cyclic-Monomeric and Dimeric Derivatives of the Snail-Derived Peptide Cm-p5 against Viral and Multidrug-Resistant Bacterial Strains

Biomolecules ◽

10.3390/biom11050745 ◽

2021 ◽

Vol 11 (5) ◽

pp. 745

Author(s):

Melaine González-García ◽

Fidel Morales-Vicente ◽

Erbio Díaz Pico ◽

Hilda Garay ◽

Daniel G. Rivera ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Antimicrobial Activity ◽

Antifungal Activity ◽

Multidrug Resistant ◽

Moderate Activity ◽

Dependent Manner ◽

Bacterial Strains ◽

Acinetobacter Baumanii ◽

Concentration Dependent Manner ◽

Conventional Antibiotics

Cm-p5 is a snail-derived antimicrobial peptide, which demonstrated antifungal activity against the pathogenic strains of Candida albicans. Previously we synthetized a cyclic monomer as well as a parallel and an antiparallel dimer of Cm-p5 with improved antifungal activity. Considering the alarming increase of microbial resistance to conventional antibiotics, here we evaluated the antimicrobial activity of these derivatives against multiresistant and problematic bacteria and against important viral agents. The three peptides showed a moderate activity against Pseudomonas aeruginosa, Klebsiella pneumoniae Extended Spectrum β-Lactamase (ESBL), and Streptococcus agalactiae, with MIC values > 100 µg/mL. They exerted a considerable activity with MIC values between 25–50 µg/mL against Acinetobacter baumanii and Enterococcus faecium. In addition, the two dimers showed a moderate activity against Pseudomonas aeruginosa PA14. The three Cm-p5 derivatives inhibited a virulent extracellular strain of Mycobacterium tuberculosis, in a dose-dependent manner. Moreover, they inhibited Herpes Simplex Virus 2 (HSV-2) infection in a concentration-dependent manner, but had no effect on infection by the Zika Virus (ZIKV) or pseudoparticles of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2). At concentrations of >100 µg/mL, the three new Cm-p5 derivatives showed toxicity on different eukaryotic cells tested. Considering a certain cell toxicity but a potential interesting activity against the multiresistant strains of bacteria and HSV-2, our compounds require future structural optimization.

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Multidrug ResistantAcinetobacter baumanii: A 15-Year Trend Analysis

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2018.52 ◽

2018 ◽

Vol 39 (5) ◽

pp. 608-611 ◽

Cited By ~ 2

Author(s):

Dana L. Russell ◽

Daniel Z. Uslan ◽

Zachary A. Rubin ◽

Tristan R. Grogan ◽

Elise M. Martin

Keyword(s):

Trend Analysis ◽

Multidrug Resistant ◽

Infect Control Hosp ◽

Acinetobacter Baumanii

From 2000 to 2009, rates of multidrug-resistantAcinetobacter baumaniiincreased 10-fold to 0.2 per 1,000 patient days. From 2010 to 2015, however, rates markedly declined and have stayed below 0.05 per 1,000 patient days. Herein, we present a 15-year trend analysis and discuss interventions that may have led to the decline.Infect Control Hosp Epidemiol2018;39:608–611

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