scholarly journals Optochin Revisited: Defining the Optimal Type of Blood Agar for Presumptive Identification of Streptococcus pneumoniae

1998 ◽  
Vol 36 (3) ◽  
pp. 833-834 ◽  
Author(s):  
M. A. Gardam ◽  
M. A. Miller
Keyword(s):  
Streptococcus Pneumoniae ◽  
Susceptibility Testing ◽  
Blood Agar ◽  
Sheep Blood ◽  
Mueller Hinton ◽  
Columbia Agar ◽  
Presumptive Identification ◽  
Mueller Hinton Agar ◽  
Inhibition Zones ◽  
Optimal Type

To determine the optimal media for optochin susceptibility testing of Streptococcus pneumoniae, we measured inhibition zones for 72 S. pneumoniae and 22 Streptococcus viridans isolates on three blood-containing media. Because 15.3, 0, and 22.2% of S. pneumoniae organisms were misidentified on Columbia agar, Trypticase soy agar (TSA), and Mueller-Hinton agar, respectively, each containing sheep blood, we recommend that TSA-sheep blood agar be used.

scholarly journals Improved Detection of Streptococcus pneumoniae in Middle-Ear Fluid Cultures by Use of a Gentamicin-Containing Medium

1999 ◽  
Vol 37 (10) ◽  
pp. 3415-3416
Author(s):  
Nechama Peled ◽  
Pablo Yagupsky
Keyword(s):  
Streptococcus Pneumoniae ◽  
Middle Ear ◽  
Agar Medium ◽  
Blood Agar ◽  
Sheep Blood ◽  
Routine Blood ◽  
Middle Ear Fluid ◽  
Columbia Agar

The performance of Columbia agar medium with added sheep blood and gentamicin (CAG) for isolation of Streptococcus pneumoniaefrom middle-ear fluid cultures was compared to that of routine blood agar medium (BA). Of 238 pneumococcal isolates recovered, CAG plates detected 233 (97.9%) but BA plates detected only 208 (87.4%) (P < 0.001).

scholarly journals Determination of Trimethoprim-Sulfamethoxazole Resistance in Streptococcus pneumoniae by Using the E Test with Mueller-Hinton Agar Supplemented with Sheep or Horse Blood May Be Unreliable

1999 ◽  
Vol 37 (1) ◽  
pp. 215-217 ◽  
Author(s):  
M. Lovgren ◽  
L. Dell’Acqua ◽  
R. Palacio ◽  
G. Echániz-Aviles ◽  
A. Soto-Noguerón ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Clinical Laboratory ◽  
Reference Method ◽  
Error Rates ◽  
National Committee ◽  
Defibrinated Sheep Blood ◽  
Sheep Blood ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Horse Blood

An international, multicenter study compared trimethoprim-sulfamethoxazole MICs for 743 Streptococcus pneumoniae isolates (107 to 244 isolates per country) by E test, using Mueller-Hinton agar supplemented with 5% defibrinated horse blood or 5% defibrinated sheep blood, with MICs determined by the National Committee for Clinical Laboratory Standards broth microdilution reference method. Agreement within 1 log2dilution and minor error rates were 69.3 and 15.5%, respectively, on sheep blood-supplemented agar and 76.9 and 13.6%, respectively, with horse blood as the supplement. Significant interlaboratory variability was observed. E test may not be a reliable method for determining the resistance of pneumococci to trimethoprim-sulfamethoxazole.

scholarly journals Applicability and performance of EUCAST’s rapid antimicrobial susceptibility testing (RAST) on primarily sterile body fluids in blood culture bottles in laboratory routine with total lab automation

2021 ◽  
Author(s):  
Jasmin Kaur Jasuja ◽  
Stefan Zimmermann ◽  
Irene Burckhardt
Keyword(s):  
Blood Culture ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Body Fluids ◽  
E Coli ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
And Performance ◽  
Sterile Body Fluids ◽  
Better Than

AbstractOptimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST’s RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed.

scholarly journals 1457. Serial Passage of Enterobacteriaceae to Explore Development of Carbapenem Resistance

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S731-S731
Author(s):  
Yosef Nissim ◽  
Douglas Slain ◽  
P Rocco LaSala
Keyword(s):  
Susceptibility Testing ◽  
Klebsiella Oxytoca ◽  
Carbapenem Resistance ◽  
Serial Passage ◽  
Resistant Isolate ◽  
Mueller Hinton ◽  
The Us ◽  
Zones Of Inhibition ◽  
Mueller Hinton Agar ◽  
The Impact

Abstract Background Carbapenems are broad-spectrum antibacterials that have seen increased usage for the Enterobacteriales family in recent years. While carbapenem usage has been associated with increased antibacterial resistance, there is currently a lack of data comparing the risk of reduced susceptibility selection by the two most commonly used carbapenems in the US, ertapenem (ERT) and meropenem (MER). We conducted a novel serial passage experiment with clinical isolates of Enterobacteriales to assess the impact of repeated exposure to ERT or MER on phenotypic susceptibility patterns. Methods Non-duplicate clinical Enterobacteriales isolates were selected randomly for inclusion. Antimicrobial susceptibility testing was performed by CLSI disc diffusion methods. Standardized suspensions of isolates were plated on Mueller-Hinton agar, and ERT (10mcg) and MER (10mcg) discs applied. Zones of inhibition were measured and recorded after 16-18 hours incubation. Growth from the innermost zone of inhibition around each disc was used to prepare subsequent suspensions for serial susceptibility testing. This process would be repeated daily for 10 days. Each subsequent serially-passaged isolated was tested against both ERT and MER. Daily zones of inhibition were measured and interpreted. Baseline & final susceptibilities were determined by automated methods (Vitek 2). Results Seventeen Enterobacteriaceae isolates were selected, including: Klebsiella pneumoniae (n=11), Klebsiella oxytoca (n=2), Escherichia coli (n=1), Morganella morganii (n=1), and Enterobacter cloacae (n=2). Despite a greater degree of reductions in zones of inhibition with repeated ERT exposure (vs MER), the overall 10 day trends were not found to be significant different (P=0.529). Resistance developed to ERT in six isolates compared to one MER-resistant isolate (P = 0.053). E. cloacae was the only species to show a significant change between drugs (P=0.010). Two of three isolates that developed reduced zone changes &gt; 10mm to MER were initially exposed to ERT on an earlier plate. Conclusion This novel experiment identified the development of some nonsignificant reductions in susceptibility with ERT after serial exposure. Results from this pilot study should encourage larger well-designed studies in this area. Disclosures All Authors: No reported disclosures

scholarly journals Russia-made Mueller–Hinton agar: compliance with contemporary requirements

2019 ◽  
Vol 9 (2) ◽  
pp. 409-416
Author(s):  
L. V. Domotenko ◽  
I. S. Kosilova ◽  
A. P. Shepelin
Keyword(s):  
Quality Control ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Nutrient Media ◽  
Mueller Hinton ◽  
Mueller Hinton Agar

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.  

scholarly journals Isolation, Identification And Prevalence Of Pseudomonas Aeruginosa Isolates From Clinical And Environmental Sources In Onitsha Metropolis, Anambra State

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
C. O. Ezeador ◽  
P. C. Ejikeugwu ◽  
S. N. Ushie ◽  
N. R. Agbakoba
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Prevalence Rate ◽  
Nasal Swab ◽  
Blood Agar ◽  
Biochemical Tests ◽  
Anambra State ◽  
Mueller Hinton ◽  
Bluish Green ◽  
Mueller Hinton Agar

This study was aimed to isolate and identify Pseudomonas aeruginosa and to determine the prevalence rate of isolated P. aeruginosa in Hospitals in Onitsha. Isolates of P. aeruginosa were recovered from both clinical and environmental sources using Cetrimide agar, Blood agar, Mueller-Hinton agar and MacConkey agar.  All the inoculated plates were incubated at 37°C for 24-48 hours and growth was evaluated on these media. Isolates were identified on the basis of standard bacteriological methods like morphology, colonial characteristics, smell in culture, haemolysis, as well as pigment production on these media. All suspected isolates were further characterized and identified by many biochemical reactions. Results revealed that only 22 (18.3%) isolates were P. aeruginosa, while other 98 (81.7%) represented other bacterial genera. The 22 isolates included 19 (86.4%) environmental isolates and 3 (13.6%) clinical isolates. Pseudomonas aeruginosa was most commonly isolated from sink (13.6%), then mops and cleaning buckets (9.1%) and least from theatre bed, nasal swab, floor, disinfectant, ear and wound swab (4.5%). The pigment varied from bluish-green to yellowish-green with a grape-like odor. All isolates were Gram negative, produced β-hemolysis on blood agar and were motile. The biochemical tests showed all the isolates to be strongly positive for catalase, oxidase, citrate, and casein hydrolysis. The prevalence rate of P. aeruginosa is relatively high and its isolation from sources like sinks and theatre bed could be suggestive of the role of this pathogen in nosocomial infections.

Susceptibilities of invasive Neisseria meningitidis strains to agents used for prophylaxis and to penicillin G

2021 ◽  
pp. e20200034
Author(s):  
Carrie Phillips ◽  
David JM Haldane
Keyword(s):  
Cerebrospinal Fluid ◽  
Nova Scotia ◽  
Neisseria Meningitidis ◽  
Antimicrobial Susceptibility ◽  
Penicillin G ◽  
Minimal Inhibitory Concentrations ◽  
Sheep Blood ◽  
Mueller Hinton ◽  
Mueller Hinton Agar

Antimicrobial susceptibility of 50 Neisseria meningitidis strains detected in Nova Scotia between 2004 and 2018 was determined. The isolates were cultured from sites that might prompt chemoprophylaxis (27 blood, 18 cerebrospinal fluid [CSF], 3 CSF–blood, and 2 conjunctiva). Minimal inhibitory concentrations (MICs) were determined to azithromycin, ciprofloxacin, minocycline, rifampin, trimethoprim–sulfamethoxazole, and penicillin G, using a diffusion gradient strip on Mueller–Hinton agar with 5% sheep blood in 5% CO2 for 20–24 hours. All isolates remained susceptible to azithromycin, ciprofloxacin, minocycline, and rifampin, but there was 26% resistance to trimethoprim–sulfamethoxazole. There was a rise in penicillin MIC of the isolates over the study period.

scholarly journals Drug Susceptibility Testing and Synergistic Antibacterial Activity of Curcumin with Antibiotics against Enterotoxigenic Escherichia coli

Antibiotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 43 ◽  
Author(s):  
Rangel-Castañeda Itzia Azucena ◽  
Cruz-Lozano José Roberto ◽  
Zermeño-Ruiz Martin ◽  
Cortes-Zarate Rafael ◽  
Hernández-Hernández Leonardo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clavulanic Acid ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Enterotoxigenic Escherichia Coli ◽  
Antimicrobial Drugs ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Amoxicillin Clavulanic Acid

Aim: This study investigated the susceptibility of Enterotoxigenic Escherichia coli to curcumin, as well as its synergistic effect with 12 antimicrobial drugs. Methods and Results: Our study shows that curcumin did not affect bacterial growth. The antimicrobial susceptibility of curcumin and antibiotic synergy were identified using disc diffusion on Mueller-Hinton agar. The strain of Enterotoxigenic Escherichia coli used was resistant to Ampicillin, Amoxicillin/Clavulanic acid, Ampicillin/Sulbactam, Ciprofloxacin, and Cefazolin. There was synergy between curcumin and the majority of antibiotics tested. Maximum synergy was observed with combinations of 330 µg/mL curcumin and Ceftazidime, followed by Cefotaxime, Amoxicillin/Clavulanic acid, Ampicillin, Aztreonam, Trimethoprim, Ciprofloxacin, Ceftriaxone, Cefazolin, Tetracycline, and Imipenem. Conclusion: Our findings indicated that curcumin might be useful as a combinatorial strategy to combat the antibiotic resistance of Enterotoxigenic Escherichia coli.

scholarly journals OptimizedIn VitroAntibiotic Susceptibility Testing Method for Small-Colony Variant Staphylococcus aureus

2016 ◽  
Vol 60 (3) ◽  
pp. 1725-1735 ◽  
Author(s):  
Mimi R. Precit ◽  
Daniel J. Wolter ◽  
Adam Griffith ◽  
Julia Emerson ◽  
Jane L. Burns ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Susceptibility Testing ◽  
Brain Heart Infusion ◽  
Chronic Infections ◽  
Poor Growth ◽  
Content Type ◽  
Treatment History ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Small Colony

Staphylococcus aureussmall-colony variants (SCVs) emerge frequently during chronic infections and are often associated with worse disease outcomes. There are no standardized methods for SCV antibiotic susceptibility testing (AST) due to poor growth and reversion to normal-colony (NC) phenotypes on standard media. We sought to identify reproducible methods for AST ofS. aureusSCVs and to determine whether SCV susceptibilities can be predicted on the basis of treatment history, SCV biochemical type (auxotrophy), or the susceptibilities of isogenic NC coisolates. We tested the growth and stability of SCV isolates on 11 agar media, selecting for AST 2 media that yielded optimal SCV growth and the lowest rates of reversion to NC phenotypes. We then performed disk diffusion AST on 86S. aureusSCVs and 28 isogenic NCs and Etest for a subset of 26 SCVs and 24 isogenic NCs. Growth and reversion were optimal on brain heart infusion agar and Mueller-Hinton agar supplemented with compounds for which most clinical SCVs are auxotrophic: hemin, menadione, and thymidine. SCVs were typically nonsusceptible to either trimethoprim-sulfamethoxazole or aminoglycosides, in accordance with the auxotrophy type. In contrast, SCVs were variably nonsusceptible to fluoroquinolones, macrolides, lincosamides, fusidic acid, and rifampin;mecA-positive SCVs were invariably resistant to cefoxitin. All isolates (both SCVs and NCs) were susceptible to quinupristin-dalfopristin, vancomycin, minocycline, linezolid, chloramphenicol, and tigecycline. Analysis of SCV auxotrophy type, isogenic NC antibiograms, and antibiotic treatment history had limited utility in predicting SCV susceptibilities. With clinical correlation, this AST method and these results may prove useful in directing treatment for SCV infections.

Sign in / Sign up

Export Citation Format

Share Document