A rapid technique for detection of resistance to chloramphenicol in Streptococcus pneumoniae and comparison with minimum inhibitory concentration and disk-diffusion methods

Abstract Introduction Typhoid fever, caused by Salmonella typhi and paratyphi, is a generalized infection with case fatality of about 10%. The symptoms may be severe, with life threatening sequelae of infection in a proportion of cases. Antimicrobial agents are the mainstay of therapy in enteric fever so as to prevent the complications associated with severe illness and mortality in the patients. Fluoroquinolones (e.g., ciproﬂoxacin) are very effective against completely susceptible Salmonella bacteria. However, their efﬁcacy is doubtful once any resistance is detected. Peﬂoxacin testing has ultimately helped in the accurate identiﬁcation of quinolone susceptibility for a better therapeutic success rate. In the present study we have tried to evaluate the quinolone susceptibility in Salmonella isolates based on minimum inhibitory concentration (MIC) determination. Materials and Methods The method used in the study is quinolone susceptibility in Salmonella isolates based on MIC determination. Salmonella isolates show intermediate susceptibility to ciprofloxacin using disk diffusion. Both ciprofloxacin and pefloxacin MIC evaluation has been done to corroborate the results with pefloxacin disk diffusion testing. Results There was a positive correlation between the susceptibility to ciprofloxacin and pefloxacin. However, the isolates with intermediate susceptibility had variations in terms of susceptibility to pefloxacin. MIC values for pefloxacin and our findings suggested that pefloxacin susceptible on disk diffusion as per Clinical and Laboratory Standards Institute guidelines showed lower values for MIC using Pefloxacin HICOMB test and pefloxacin resistant isolates showed higher MIC values.

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Minimum Inhibitory Concentration Breakpoints and Disk Diffusion Inhibitory Zone Interpretive Criteria for Tilmicosin Susceptibility Testing against Pasteurella Multocida and Actinobacillus Pleuropneumoniae Associated with Porcine Respiratory Disease

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870201400505 ◽

2002 ◽

Vol 14 (5) ◽

pp. 389-395 ◽

Cited By ~ 8

Author(s):

Thomas R. Shryock ◽

J. Mitchell Staples ◽

David C. DeRosa

Keyword(s):

Minimum Inhibitory Concentration ◽

Respiratory Disease ◽

Pasteurella Multocida ◽

Susceptibility Testing ◽

Inhibitory Concentration ◽

Actinobacillus Pleuropneumoniae ◽

Disk Diffusion ◽

Pharmacokinetic Data ◽

In Vitro Test ◽

Porcine Respiratory

Tilmicosin is a novel macrolide antibiotic developed for exclusive use in veterinary medicine. Tilmicosin has been approved as a feed premix to control porcine respiratory disease associated with Pasteurella multocida and Actinobacillus pleuropneumoniae. The development of antimicrobial susceptibility testing guidelines for tilmicosin was predicated on the relationship of clinical efficacy studies that demonstrated a favorable therapeutic outcome, on pharmacokinetic data, and on in vitro test data, as recommended by the National Committee for Clinical Laboratory Standards (NCCLS). The approved breakpoints for the minimum inhibitory concentration dilution testing for both species are resistant, ≥32 μg/ml, and susceptible, ≤16 μg/ml. The zone of inhibition interpretive criteria for disk diffusion testing with a 15-μg tilmicosin disk are resistant, ≤10 mm, and susceptible, ≥11mm.

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Streptococcus pneumoniae and Haemophilus influenzae as etiological agents of conjunctivitis outbreaks in the region of Ribeirão Preto, SP, Brazil

Revista do Instituto de Medicina Tropical de São Paulo ◽

10.1590/s0036-46651998000100002 ◽

1998 ◽

Vol 40 (1) ◽

pp. 7-10 ◽

Cited By ~ 8

Author(s):

Marta I. C. MEDEIROS ◽

Suzel N. NEME ◽

Paulo da SILVA ◽

Jaqueline O. SILVA ◽

Ana Maria M. CARNEIRO ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Minimum Inhibitory Concentration ◽

Haemophilus Influenzae ◽

Inhibitory Concentration ◽

Intermediate Resistance ◽

Concentration Test ◽

Etiological Agents ◽

Age Range

In the study of conjunctivitis outbreaks occurring from September 1994 to September 1996 in the region of Ribeirão Preto, conjunctival exudates of 92 patients were cultivated in Instituto Adolfo Lutz Laboratory I, Ribeirão Preto. Most cases occurred in the age range 2-7 years. The etiological agents which were most frequently isolated from the analyzed cases were: Streptococcus pneumoniae and Haemophilus influenzae, in 40.22% and 21.74%, respectively. 51.35% of the S. pneumoniae isolated strains were not typable. The oxacillin-resistant S. pneumoniae strains were submitted to the minimum inhibitory concentration test (MIC) and three of them presented intermediate resistance, whereas only one was highly resistant to penicillin.

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Antimicrobial Testing of Selected Fluoroquinolones Against Pseudomonas aeruginosa Isolated From Canine Otitis

Journal of the American Animal Hospital Association ◽

10.5326/0430307 ◽

2007 ◽

Vol 43 (6) ◽

pp. 307-312 ◽

Cited By ~ 13

Author(s):

Lindsay McKay ◽

Crystal D. Schuman Rose ◽

Jennifer L. Matousek ◽

Lynn S. Schmeitzel ◽

Nicole M. Gibson ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Minimum Inhibitory Concentration ◽

Susceptibility Testing ◽

Inhibitory Concentration ◽

Disk Diffusion

A total of 100 Pseudomonas aeruginosa (P. aeruginosa) isolates were collected over a 1.5- year period from cases of canine otitis. Sensitivities to enrofloxacin, marbofloxacin, and orbifloxacin were determined using minimum inhibitory concentration testing (MICT). Isolates were also tested for sensitivities to enrofloxacin and marbofloxacin using disk-diffusion susceptibility testing (DDST). Isolates were significantly more sensitive to marbofloxacin than to enrofloxacin (z = −4.57; P<0.05) or orbifloxacin (z = −5.02; P<0.05). Agreement was 87% between MICT and DDST for marbofloxacin, with approximately equal numbers of overestimation and underestimation errors. Agreement was 74% between MICT and DDST for enrofloxacin, but DDST tended to overestimate the number of enrofloxacin-susceptible strains. These results suggest that marbofloxacin is more effective against P. aeruginosa than either enrofloxacin or orbifloxacin and that relying on DDST may lead to ineffective enrofloxacin treatment.

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Determination of Phenolic Compounds with Antimicrobial Activity of Byrsonima Crassifolia and Inga Edulis Leaves Extracts

Ensaios e Ciência C Biológicas Agrárias e da Saúde ◽

10.17921/1415-6938.2021v25n1p21-28 ◽

2021 ◽

Vol 25 (1) ◽

pp. 21-28

Author(s):

Victor Hugo Alves do Nascimento ◽

Alessandra Carla Guimarães Sobrinho ◽

Cintya De Oliveira Souza ◽

Jesus Nazareno Silva de Souza ◽

Consuelo Lúcia Sousa

Keyword(s):

Antimicrobial Activity ◽

Phenolic Compounds ◽

Minimum Inhibitory Concentration ◽

Gallic Acid ◽

Inhibitory Concentration ◽

Disk Diffusion ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Inga Edulis ◽

Byrsonima Crassifolia

The aim of this work was to determine the compounds with antimicrobial capacity from crude extracts and leaf fractions of Byrsonima crassifolia and Inga edulis. A solid-liquid extraction was performed using three solvent systems (acetate, methanol and methanol: water). The extracts and fractions were submitted to antimicrobial susceptibility tests for Gram-negative and Gram-positive bacteria by disk diffusion and Minimum Inhibitory Concentration (MIC) methods. A solid phase extraction (SPE) was performed to identify phenolic compounds for pre-concentration and pre-purification of the extracts and fractions that presented antimicrobial potential. The methanolic fraction was able to extract the highest total phenolic content and also presented the largest halos in the disk diffusion test. The minimum inhibitory concentration ranged from 125 to 500 μg/ml mL-1 and from 12.5 to 200 μg/ml mL-1 for Gram-negative and Gram-positive bacteria, respectively. After SPE, the crude extracts and fractions showed inhibition halos against all themicroorganisms tested at a lower concentration when compared to the standardized antibiotics. Gallic acid, ferric acid, myricetin and quercetin showed antimicrobial activity when tested alone. Gallic acid, catechin, epicatechin, ferrulic acid, quercetin, and other 4 major compounds were identified and quantified for Byrsonima crassifolia and 3 compounds for Inga edulis. Keywords: Vegetable Matrices. Antibiotics. Bioactive Compounds. Liquid Chromatography. Resumo O objetivo do presente estudo foi determinar compostos com capacidade antimicrobiana de extratos brutos e frações de folhas de Byrsonima crassifolia e de Inga edulis. Foi realizado uma extração sólido-líquido utilizando três sistemas de solventes (acetato, metanol e metanol:água). Os extratos e frações foram submetidos aos testes de suscetibilidade antimicrobiana para bactérias Gram-negativas e Gram-positivas através dos métodos de disco-difusão e Concentração Inibitória Mínima-CIM. Para identificação dos compostos fenólicos foi realizada Extração em Fase Sólida (SPE), para pré- concentração e pré-purificação dos extratos e frações que apresentaram potencial antimicrobiano. A fração metanólica conseguiu extrair maior conteúdo de fenólicos totais, e apresentou os maiores halos no teste de disco-difusão. A concentração inibitória mínima variou de 125 a 500 µgES mL-1 e de 12,5 a 200 µgES mL-1 para bactérias Gram-negativas e Gram-positivas, respectivamente. Após SPE, os extratos brutos e frações apresentaram halos de inibição frente a todos os micro-organismos testados em uma concentração menor que a dos antibióticos padronizados. O ácido gálico, ácido ferrúlico, miricetina e quercetina apresentaram atividade antimicrobiana quando testados isoladamente. Foram identificados e quantificados nos extratos brutos e frações ácido gálico, catequina, epicatequina, ácido ferrúlico, quercetina, além de outros 4 compostos majoritários para Byrsonima crassifolia e 3 compostos para Inga edulis. Palavras-chave: Matrizes Vegetais. Antibióticos. Compostos Bioativos. Cromatografia Líquida.

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β-Lactam Activity against Penicillin-Resistant Streptococcus pneumoniae Strains Exhibiting Higher Amoxicillin versus Penicillin Minimum Inhibitory Concentration Values: An in vitro Pharmacodynamic Simulation

Chemotherapy ◽

10.1159/000118659 ◽

2008 ◽

Vol 54 (2) ◽

pp. 84-90 ◽

Cited By ~ 3

Author(s):

D. Sevillano ◽

L. Aguilar ◽

L. Alou ◽

M.J. Giménez ◽

N. González ◽

...

Keyword(s):

Streptococcus Pneumoniae ◽

Minimum Inhibitory Concentration ◽

Inhibitory Concentration ◽

Beta Lactam

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Renaissance of Conventional First-Line Antibiotics inSalmonella entericaClinical Isolates: Assessment of MICs for Therapeutic Antimicrobials in Enteric Fever Cases from Nepal

BioMed Research International ◽

10.1155/2017/2868143 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 2

Author(s):

Puspa Raj Khanal ◽

Deepa Satyal ◽

Anjeela Bhetwal ◽

Anjila Maharjan ◽

Shreena Shakya ◽

...

Keyword(s):

Minimum Inhibitory Concentration ◽

Antimicrobial Susceptibility ◽

Salmonella Enterica ◽

Enteric Fever ◽

Susceptibility Testing ◽

Inhibitory Concentration ◽

Antimicrobial Susceptibility Testing ◽

Clinical Isolates ◽

Disk Diffusion ◽

Blood Samples

Enteric fever caused bySalmonella entericais a life-threatening systemic illness of gastrointestinal tract especially in tropical countries. Antimicrobial therapy is generally indicated but resistance towards commonly used antibiotics has limited their therapeutic usefulness. Therefore, we aimed to determine the antimicrobial susceptibility pattern by minimum inhibitory concentration method of common therapeutic regimens againstSalmonella entericafrom enteric fever clinical cases.Salmonella entericaclinical isolates recovered from the patients with suspected enteric fever whose blood samples were submitted to microbiology laboratory of Manmohan Memorial Community Hospital, Kathmandu, from March 2016 to August 2016, were studied. These isolates were subjected to antimicrobial susceptibility testing against common therapeutic antimicrobials by Kirby-Bauer disk diffusion method. The minimum inhibitory concentration of ciprofloxacin, azithromycin, chloramphenicol, and cefixime was determined by Agar dilution method based on the latest CLSI protocol. A total of 88 isolates ofSalmonella entericawere recovered from blood samples of enteric fever cases. Out of them, 74 (84.09%) wereSalmonellaTyphi and 14 (15.91%) wereSalmonellaParatyphi A. On Kirby-Bauer disk diffusion antimicrobial susceptibility testing, entire isolates were susceptible to cotrimoxazole, cefixime, ceftriaxone, azithromycin, and chloramphenicol. Sixty-four (72.7%)Salmonella entericaisolates were nalidixic acid resistant and nonsusceptible to ciprofloxacin and levofloxacin. On MIC determination, fourSalmonellaisolates were ciprofloxacin resistant with MIC 1 µg/ml and two isolates were ciprofloxacin intermediate with MIC 0.5 µg/ml. The MIC range of azithromycin was from 0.125 µg/ml to 2.0 µg/ml, whereas that for chloramphenicol was 2.0 µg/ml–8.0 µg/ml and for cefixime was 0.0075–0.5 µg/ml, respectively. Despite global surge of antimicrobial resistance amongSalmonella entericaclinical isolates, the level of drug resistance in our study was not so high. However, higher level of NARST strains limits therapeutic use of fluoroquinolones and necessitates the routine monitoring of such resistance determinants in order to effectively and rationally manage enteric fever cases.

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