scholarly journals Susceptibility testing of tigecycline against Acinetobacter spp. by disc diffusion method: withdrawing a therapeutic option by varying the Mueller-Hinton agar?

2008 ◽  
Vol 62 (6) ◽  
pp. 1463-1464 ◽  
Author(s):  
L. F. Canigia ◽  
C. Bantar
2019 ◽  
Vol 9 (2) ◽  
pp. 409-416
Author(s):  
L. V. Domotenko ◽  
I. S. Kosilova ◽  
A. P. Shepelin

At present, a rise of antimicrobial resistance requires that susceptibility of infectious agents to antimicrobial agents could be accurately evaluated as related errors may lead to selecting improper therapeutics provoking spread of drug resistance. Pathogen sensitivity to antimicrobial agents is commonly determined by a disc diffusion method. A quality of nutrient medium used in assays plays a crucial role influencing final results. In Russia, it turned out that regulatory documents such as the nationwide guidelines and clinical recommendations outlining methodology for antimicrobial susceptibility testing underlay availability in domestic market few nutrient media, including Mueller–Hinton Agar, AGV medium etc. exhibiting sometimes unsatisfactory quality. To harmonize such methodology with international requirements, theStateResearchCenterfor Applied Microbiology and Biotechnology has developed a technology and promoted manufacture of Russia-made Mueller–Hinton agar satisfying requirements of EUCAST documents, clinical guidelines, and ISO/TS 16782:2016. The main objective of this study was to compare quality of new agar product with five similar foreign media while examining 11 test strains by disc diffusion method. As a result, some of nutrient media available to the Russian market turned out to be off-standard: not all of them satisfy to the EUCAST requirements and clinical guidelines since diameter distribution for growth inhibition recommended by EUCAST for quality control does not fit into permissible range. Moreover, susceptibility of P. aeruginosa ATCC 27853 to aminoglycosides, fluoroquinolones, Meropenem, as well as S. aureus ATSS 25923 and E. faecalis ATCC 29212 to tigecycline was assessed with certain mistakes. The data obtained by us were analyzed in accordance to the new document ISO/TS 16782:2016 “Clinical laboratory testing — criterion for acceptable lots of dehydrated Mueller–Hinton agar and broth for antimicrobial susceptibility testing”, not approved yet In Russia. To determine potential reason for deviation of data from reference range, we measured concentration of bivalent metals in all nutrient media examined by atomic emission spectrometry with inductively coupled plasma. We determined new patterns affecting reliability of results on microbial antibiotic susceptibility. A need to check intralaboratory quality control of nutrient media was emphasized.  


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Anwar Ali Chandio ◽  
Ayaz Ali Memon ◽  
Shahabuddin Memon ◽  
Fakhar N. Memon ◽  
Qadeer Khan Panhwar ◽  
...  

Present study deals with the synthesis of the p-tert-butylcalix[4]arene diamide derivative as ligand (L) and its Fe3+ complex, followed by its characterization using TLC and FT-IR, while UV-Vis and Job’s plot study were performed for complex formation. Antimicrobial activity of the derivative (L) and its metal complex was carried out by the disc diffusion method against bacteria (Escherichia coli and Staphylococcus albus) and fungi (R. stolonifer). Different concentrations of the derivative (L) (6, 3, 1.5, 0.75, and 0.37 μg/mL) and its Fe3+ complex were prepared, and Mueller–Hinton agar was used as the medium for the growth of microorganisms. Six successive dilutions of the derivative (L) and Fe3+ complex were used against microorganisms. Two successive dilutions (6 and 3 μg/mL) of the derivative (L) showed antibacterial action against both Gram-positive and Gram-negative bacteria. In addition, three successive dilutions (6, 3, and 1.5 μg/mL) of the derivative (L) showed antifungal activity. However, all of six dilutions of the Fe3+ complex showed antimicrobial activity. Derivative (L) showed 3 and 1.5 μg/mL minimum inhibitory concentrations (MIC) against bacteria and fungi, respectively. On the contrary, its Fe3+ complex showed 0.37 μg/mL value of MIC against bacteria and fungi. Hence, Fe3+ complex of the derivative (L) was found to be a more effective antimicrobial agent against selected bacteria and fungi than the diamide derivative (L).


2017 ◽  
Vol 62 (No. 7) ◽  
pp. 410-415 ◽  
Author(s):  
J. Bzdil ◽  
O. Holy ◽  
J. Toporcak

The aim of this study was to describe two case studies of reptile disease, in which the primary pathogen was apparently Salmonella enterica subspecies enterica serovar Paratyphi B. Pathological examinations, sampling from different organs and cloacal swabs was performed on a dead savannah monitor (Varanus exanthematicus) and a sick green tree python (Chondropython viridis). This material was subjected to culture examination, including selective enrichment using standard methods. Typing was performed using MALDI-TOF and strains were also serologically typified. The utilisation of d-tartrate was confirmed biochemically and also using PCR. Antibiotic susceptibility was determined by the standard disc diffusion method using Mueller-Hinton agar without blood and antibiotic discs. In both cases the detected Salmonella enterica subspecies enterica serovar Paratyphi B was positive for d-tartrate and exquisitely susceptible to chloramphenicol, tetracycline, ampicillin, amoxycillin/clavulanic acid, gentamicin, ceftazidime, enrofloxacin and piperacillin.


2002 ◽  
Author(s):  
◽  
Mbuso Mabuza

The aim of this in vitro microbial study was to evaluate the efficacy of Calendula officinalis tincture 60% (v/v) ethanol as an antibacterial on in vitro Pseudomonas aeruginosa. The standardised disc - diffusion method was employed. Seven pairs of Mueller - Hinton agar plates were used.


Author(s):  
Gaurab Risal ◽  
Aayush Shrestha ◽  
Saroj Kunwar ◽  
Gajal Paudel ◽  
Rameshwor Dhital ◽  
...  

Background: In urinary tract infections, an important role is played by bacterial biofilms which are responsible for persistence infections together with the antimicrobial resistance. Higher resistance can be seen in biofilm forming uropathogens in comparison with free-floating bacteria. So, the present study was performed with a goal to find the prevalence of biofilm formation and also the antimicrobial resistant pattern of uropathogens.Methods: A descriptive method was conducted at Modern Technical College, Sanepa, Lalitpur in samples isolated from UTI suspected patients. The overall duration of this study was approximately 3 months. Total of 50 isolated E. coli was tested for biofilm formation and antimicrobial susceptibility testing was done by Kirby-Bauer disc diffusion method on Mueller Hinton agar as per CLSI guidelines.Results: From the 50 isolates of E. coli, 32 were biofilm producers (3 strong and 29 moderate) and 18 were weak/non-biofilm producers. Among the biofilm producers, cefotaxime was more resistant in 20 of the isolates followed by ceftriaxone in 16 and amoxyclav in 13, whereas amikacin was least resistant in 2 of the isolates.Conclusions: Among the isolated E. coli, biofilm-forming isolates showed higher antimicrobial resistance as compared to the non-biofilm producer. Thus, uropathogen should be routinely screened for biofilm formation. 


2009 ◽  
Vol 58 (6) ◽  
pp. 837-838 ◽  
Author(s):  
T. Das ◽  
H. S. Deshmukh ◽  
A. Mathai ◽  
Ashok Kumar Reddy

Stenotrophomonas maltophilia is gaining importance as a community-acquired pathogen, after becoming firmly established as a nosocomial pathogen. Here we report a case of endogenous endophthalmitis due to S. maltophilia. Antibiotic-susceptibility testing of the isolate was performed by the Kirby–Bauer disc diffusion method. The organism was resistant to aminoglycosides, imipenem, ticarcillin and cotrimoxazole and was sensitive to ceftazidime and chloramphenicol. The patient was successfully treated with a sensitivity-based intravitreal antibiotic regimen.


2016 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Maite Micaelo ◽  
Florence Brossier ◽  
Nicolas Brechot ◽  
Charles Edouard Luyt ◽  
Qin Lu ◽  
...  

Objectives: Carbapenems are among the most powerful anti pseudomonal agents. Since meropenem and doripenem were marketed, there are limited data regarding drug susceptibility testing by routine methods (disc diffusion and Etest) for them. The aim of our study was to compare in vitro activity of the imipenem, meropenem and doripenem against Pseudomonas aeruginosa. Methods: Three hundred and eleven P. aeruginosa strains isolated from respiratory specimens in 170 patients who developed ventilator-associated pneumonia in two intensive care units were collected over a period of 31 months. The susceptibility of all of these isolates to imipenem, meropenem and doripenem were determined by Etest and disc diffusion method. Results: Considering either all of the isolates or only the first isolates recovered per patient (311 and 170 respectively) the susceptibility rate for doripenem was higher than that for meropenem and imipenem. When MICs determined by Etest were converted into interpretative categories (S, I, R) using French (CA-SFM) guidelines, agreement was poor, especially for meropenem and doripenem. The percent of agreement with the disc diffusion method were 90.6% and 89.7% for imipenem, 80.5% and 82.6% for meropenem and 80.5% and 73.3% for doripenem, for the first isolates and all of the isolates, respectively. Errors were mostly minor errors, and the rate of errors was as high as 17.7% and 16.1% for meropenem and 17.7% and 25.7% for doripenem for the first isolates and all of the isolates, respectively Conclusion: The accuracy of disc diffusion using CA-SFM guidelines appears unsatisfactory for all the three carbapenems justifying the adaptation of new guidelines for P. aeruginosa and carbapenems


2019 ◽  
Vol 11 (03) ◽  
pp. 249-252 ◽  
Author(s):  
Srirangaraj Sreenivasan ◽  
Arunava Kali ◽  
M. V. Pravin Charles ◽  
Seetha Kunigal

Abstract INTRODUCTION: The increasing drug resistance among Gram-negative uropathogens and a lack of effective oral antibiotics have limited the therapeutic options available for urinary tract infections (UTIs). This shortage of newer antibiotics has paved the way for considering the use of older antibiotics such as fosfomycin. This study aims to evaluate the in vitro susceptibility of Enterobacteriaceae isolates to fosfomycin. MATERIALS AND METHODS: In this descriptive study conducted over a period of 6 months, we processed 1500 urine samples. The Enterobacteriaceae isolates were subjected to in vitro susceptibility testing to fosfomycin, in addition to the regularly used urinary antibiotics, by Kirby–Bauer disc-diffusion method. RESULTS: Of 1500 urine samples processed, 582 samples yielded the growth of pathogens. Enterobacteriaceae accounted for 392 (67.3%) of the isolates. Among these isolates, lower rates of resistance were observed for imipenem (4.1%) and fosfomycin (13.3%). Relatively higher rates of resistance were observed for nitrofurantoin (35.5%) and amikacin (30.9%). Nalidixic acid, norfloxacin, gentamicin, cefotaxime, and cotrimoxazole showed a high resistance rate of 82.7%, 69.6%, 52.3%, 69.1%, and 71.4%, respectively. All antibiotics, except fosfomycin, were in routine clinical use in our hospital. The low resistance (13.3%) to fosfomycin is indicative of its utility as an excellent urinary antibiotic. CONCLUSIONS: Uropathogenic Enterobacteriaceae isolates displayed excellent in vitro susceptibility to fosfomycin. These in vitro findings suggest the unexplored potential of fosfomycin as a superior therapeutic option for treating uncomplicated UTI.


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