In vitroEvaluation of Various Antimicrobials against FieldMycoplasma gallisepticumandMycoplasma synoviaeIsolates in Egypt

Abstract

28Among many avian mycoplasmas, Mycoplasma gallisepticum (MG) and 29 Mycoplasma synoviae (MS) are recognized as the main etiological agents of respiratory 30 diseases and infectious synovitis in chickens and turkeys causing tremendous economic 31 losses worldwide. Therefore, proper treatment is promoted for the control of these 32 diseases. This study was the first in Egypt to evaluate the in vitro efficacy of various 33 antimicrobials against field MG and MS isolates recovered from chicken and turkey 34 flocks using both conventional microdilution and quantitative real-time PCR (qRT-PCR) 35 assays. Totally, 47 mycoplasma isolates were recovered from 160 collected tracheal 36 samples (29.4%). Of these, 44 MG (27.5%) and 3 MS (1.9%) were identified using 37 conventional and molecular assays. The in vitro susceptibilities of 4 representative 38 mycoplasma isolates (3 MG and one MS) to 8 antibiotics and 4 essential oils were 39 investigated. The tested isolates showed various susceptibilities to tested antimicrobials. 40Toldin CRD, followed by clove, cumin and cinnamon oils were commonly effective 41 against both MG and MS clinical isolates with MIC values ranging from 0.49 to 15.63 42 µg/mL. Similarly, tylvalosin was the most active antibiotic against MG and MS isolates 43 with the lowest MIC values (0.015-0.03 µg/mL). DNA copies of both MG mgc2 and MS 44 vlhA genes were markedly decreased upon treatment with majority of tested 45 antimicrobials confirming their effectiveness as was also evaluated by conventional MIC 3 46results. In conclusion, Toldin CRD and tylvalosin were found to be the most effective 47 antimicrobials in this study, which will contribute in controlling avian mycoplasma 48 infections. 49 Author Summary 52Avian mycoplasmosis is considered as one of the most prominent economic problems in 53 the commercial poultry industry worldwide. Antimicrobial therapy is the most effective 54 tool for treatment of mycoplasmas. Owing to the side effects of antibiotics and the 55 development of resistance to the currently used drugs, an increased emphasis on the use 56 of alternative antimicrobials is of utmost importance. Here, we evaluate the in vitro 57 inhibitory effects of some essential oils and various commercial antibiotics against 58 Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) field isolates using 59 micro-broth dilution method and qRT-PCR assays. We found that toldin CRD, followed 60 by clove, cumin and cinnamon oils were effective against both MG and MS clinical 61 isolates. Similarly, tylvalosin was the most active antibiotic against MG and MS isolates. 62 We also found that DNA copies of both MG mgc2 and MS vlhA genes were markedly 63 decreased upon treatment with majority of tested antimicrobials. Our study provides new 64 insights into the control of avian mycoplasma infections. 65 Introduction 66 Avian mycoplasmosis has been deemed as one of the most prominent economic 67 problems in the commercial poultry industry all over the world. More than 20 species of 4 68 genus My...

Pharmacokinetics of Tylvalosin in Broiler Turkeys (Meleagris Gallopavo) After Single Intravenous and Oral Administration

“…The maximum plasma level (C max ) of TVN after PO dosing to turkeys were 1.53 μg/mL and attained shortly (2 h) after administration. Additionally, the plasma concentration of TVN in the current study remained for 24 h higher than the MICs for TVN against several isolates of Mycoplasma gallisepticum (0.015–0.03 μg/mL) and Mycoplasma synoviae (0.015 μg/mL) isolated recently (Jan., 2017–Dec., 2018) from turkeys in Egypt (32) and TVN was found to be more effective than tilmicosin and tylosin in this study. Also, in another recent study (2014–2016), the MICs of TVN against 17 strains of Mycoplasma synoviae isolated from broiler turkeys originating from Central and Eastern Europe were ≤0.25 ug/mL (33).…”

Prudent Use of Tylosin for Treatment of Mycoplasma gallisepticum Based on Its Clinical Breakpoint and Lung Microbiota Shift

“…CO WT was formulated as 2 μg/ml. The result was similar to that of Landman et al (2008) who derived the unofficial CBP of S ≤ 1 and R ≥ 4 μg/ml for tylosin against MG ( Landman et al, 2008 ; Kreizinger et al, 2017 ; El-Hamid et al, 2019 ).…”

Detection and antibiotic resistance of Mycoplasma gallisepticum and Mycoplasma synoviae among chicken flocks in Egypt

“…Abd El-Hamid et al [42] demonstrated that MG and MS infections can be controlled by proper treatment procedures. To develop an effective antibiotic treatment for MG and MS infections, we performed MIC experiments using eight different antimicrobials against five and three different MG and MS field isolates, respectively.…”