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 Interlaboratory Comparison of Agar Dilution and Etest Methods for Determining the MICs of Antibiotics Used in Management of Neisseria meningitidis Infections

2003 ◽  
Vol 47 (11) ◽  
pp. 3430-3434 ◽  
Author(s):  
Julio A. Vázquez ◽  
Luisa Arreaza ◽  
Colin Block ◽  
Ingrid Ehrhard ◽  
Stephen J. Gray ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Antimicrobial Agents ◽  
Penicillin G ◽  
Meningococcal Infection ◽  
Polymorphism Analysis ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Resistance To Penicillin ◽  
Agar Dilution ◽  
Regional Reference

ABSTRACT Previous studies have shown that there is considerable variation in the methods and media used to determine the susceptibility of Neisseria meningitidis to antimicrobial agents in different countries. In this study, national and regional reference laboratories used a standardized methodology to determine the MICs of antibiotics used in the management of meningococcal infection. Fourteen laboratories participated in the study, determining the susceptibility to penicillin G, rifampin, cefotaxime, ceftriaxone, ciprofloxacin, and ofloxacin of a collection of 17 meningococci, of which 11 strains were previously defined as having intermediate resistance to penicillin (PenI) by sequencing and restriction fragment length polymorphism analysis of the penA gene. The MIC was determined by agar dilution and Etest with Mueller-Hinton agar (MH), MH supplemented with sheep blood (MH+B), and MH supplemented with heated (chocolated) blood. Several laboratories encountered problems obtaining confluent growth with unsupplemented MH. MH+B was considered to give the most congruent and reproducible results among the study laboratories. The modal MIC for MH+B for each antibiotic and method was calculated to define the MIC consensus, allowing assessment of each individual laboratory's data in relation to the others. The agreement in each antibiotic/method/medium combination was defined as the percentage of laboratories with a result within one dilution of the modal result. For the whole study, an agreement of 90.6% was observed between agar dilution and Etest methods. The agreement in each laboratory/antibiotic/method combination ranged from 98.2% to 69.7%, with six laboratories demonstrating agreement higher than 90% and 11 more than 80%. The ability of the laboratories to detect the PenI isolates ranged from 18.2% to 100%. The apparent difficulty in interpreting susceptibility to rifampin, particularly with the Etest method, is very interesting.

scholarly journals Helicobacter pylori: Primary Susceptibility to Clarithromycin in vitro in Nova Scotia

1997 ◽  
Vol 11 (4) ◽  
pp. 298-300 ◽  
Author(s):  
Linda M Best ◽  
David JM Haldane ◽  
Gregory S Bezanson ◽  
Sander JO Veldhuyzen
Keyword(s):  
Helicobacter Pylori ◽  
Nova Scotia ◽  
Antimicrobial Agents ◽  
Primary Resistance ◽  
Susceptibility Data ◽  
Mueller Hinton ◽  
Agar Diffusion Test ◽  
Mueller Hinton Agar ◽  
H Pylori

Resistance to antimicrobial agents is a major determinant of the efficacy of regimens to eradicateHelicobacter pylori. Clarithromycin (CLA) has become one of the most commonly used antibiotics for treatment ofH pyloriinfection. In this study, the rate of primary resistance to CLA inH pyloriisolated from patients was determined. One hundred sixty-two strains were recovered from patients before treatment. Strains were grown and inoculated onto Mueller-Hinton agar with 7% sheep blood. CLA epsilometer gradient agar diffusion test (E test) strips were used to test for susceptibility. Appropriate control organisms were tested to validate the assay. Plates were incubated at 37°C in a microaerophilic atmosphere for up to five days. E test results were easy to interpret. Strains were considered resistant if the minimum inhibitory concentration (MIC) was 2 µg/mL or greater. Three strains were resistant (two strains with MIC 8 µg/mL and one strain with MIC 12 µg/mL), and 159 strains were sensitive (MICs ranged from less than 0.016 to 0.38 µg/mL). Ninety per cent of the strains had MICs of 0.023 µg/mL. Primary resistance was 1.8%. These susceptibility data support the use of CLA for the treatment ofH pyloriin the Nova Scotia population.

scholarly journals Performance of Etest for Antimicrobial Susceptibility Testing of Abiotrophia defectiva and Granulicatella Species: TABLE 1

2016 ◽  
Vol 54 (8) ◽  
pp. 2194-2196 ◽  
Author(s):  
Michael O. Alberti ◽  
Janet A. Hindler ◽  
Romney M. Humphries
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Broth Microdilution ◽  
Mueller Hinton ◽  
Abiotrophia Defectiva ◽  
Mueller Hinton Agar

The Etest on chocolate Mueller-Hinton agar was compared to broth microdilution (BMD) for 125 isolates of nutritionally variant streptococci. Vancomycin Etests yielded 31.1% essential agreement (EA) and 20.0% categorical agreement (CA). Penicillin Etests yielded 86.0% EA and 85.6% CA, whereas ceftriaxone Etests yielded 73.6% EA and 68.0% CA.

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 Biofilm Formation and Antimicrobial Susceptibility of Non-Diphtheriae Corynebacterium Strains Isolated from Blood Cultures: First Report from Turkey

2021 ◽  
Author(s):  
Sinem Özdemir ◽  
Okan Aydoğan ◽  
Fatma Köksal Çınar
Keyword(s):  
Antimicrobial Susceptibility ◽  
Biofilm Formation ◽  
Blood Cultures ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Biofilm Production ◽  
Mueller Hinton ◽  
Corynebacterium Striatum ◽  
Mueller Hinton Agar ◽  
Resistance Rates

Objective: Non-diphtheriae Corynebacterium strains have been recognized as important pathogens after decades of confusion regarding their microbiological classification and clinical significance. The aim of this study was to identify non-diphtheriae Corynebacterium strains and the prevalence of biofilm formation and antimicrobial resistance. Method: In total, 126 non-diphtheriae Corynebacterium strains were isolated from blood cultures of inpatients with bacteremia in our hospital between January 2015 and January 2020. Blood cultures were analyzed with the Bactec-9120 system. Strains were identified using MALDI-TOF MS (Bruker Daltonics, Germany). Antimicrobial susceptibilities were determined using the Kirby-Bauer disk diffusion method on a Mueller-Hinton agar and evaluated according to EUCAST standards. Biofilm formation was assessed with the Congo Red Agar method. Results: Corynebacterium striatum and Corynebacterium matruchotii were the most prevalent with 29 and 26 isolates, respectively. Biofilm production was detected in 62.06% (18/29) of C. striatum, in 53.8% (14/26) of C. matruchotii, in 50% (9/18) of Corynebacterium afermentans, 50% (6/12) of Corynebacterium amycolatum, and in 46% (7/15) of Corynebacterium jeikeium strains. Among the five most prevalent strains, we found a high biofilm rate of 54%. The resistance rates to penicillin, clindamycin, ciprofloxacin, rifampicin, tetracycline, and gentamicin were 91.2%, 87.3%, 79.3%, 56.3%, 45.2%, and 39.6%, respectively. All 126 strains were susceptible to vancomycin and linezolid. Conclusion: Non-diphtheriae Corynebacterium strains isolated from blood cultures of hospitalized patients with bacteremia may have multidrug resistance and the ability to produce biofilm. These results emphasize the importance of identifying strains and determining their antimicrobial susceptibility and biofilm production potential.

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 Evolutionary Changes in Antimicrobial Resistance of Invasive Neisseria meningitidis Isolates in Belgium from 2000 to 2010: Increasing Prevalence of Penicillin Nonsusceptibility

2012 ◽  
Vol 56 (5) ◽  
pp. 2268-2272 ◽  
Author(s):  
Sophie Bertrand ◽  
Françoise Carion ◽  
René Wintjens ◽  
Vanessa Mathys ◽  
Raymond Vanhoof
Keyword(s):  
Antimicrobial Resistance ◽  
Neisseria Meningitidis ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Treatment ◽  
Penicillin G ◽  
Susceptible Population ◽  
Content Type ◽  
Reference Centre ◽  
Evolutionary Changes ◽  
First Choice

ABSTRACTThis study was conducted to evaluate the evolution of the antimicrobial susceptibility ofNeisseria meningitidiscausing invasive diseases in Belgium in the period of January 2000 to December 2010. A total of 1,933 cases ofN. meningitidisfrom invasive infections were analyzed by antimicrobial susceptibility testing at the Belgian Meningococcal Reference Centre. The majority of strains were susceptible to antibiotics that are currently used for the treatment and prophylaxis of meningococcal disease, but the prevalence of clinical isolates with reduced susceptibility to penicillin increased over the years. The phenotyping, genotyping, and determination of MICs of penicillin G were performed. The systematic shift of the curves toward higher penicillin MICs in the susceptible population indicated that this population became less sensitive to penicillin in this period. A 402-bp DNA fragment in the 3′ end ofpenAwas sequenced for the 296 nonsusceptible meningococcal strains isolated between 2000 and 2010 to examine the genetic diversity and evolution of theirpenAgene. In conclusion, the data obtained in our study support the statement that the position of penicillin G as a first choice in the treatment of invasive meningococcal diseases in Belgium should be reexamined. Despite an important number of isolates displaying a reduced susceptibility to penicillin, at present the expanded-spectrum cephalosporins, such as ceftriaxone, are not affected. The follow-up of the evolutionary changes in antimicrobial resistance has also proved to be essential for the recommendation of an appropriate antimicrobial treatment for invasive meningococcal diseases.

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