scholarly journals Quinolone Susceptibility in Salmonella Isolates Based on Minimum Inhibitory Concentration Determination

2020 ◽  
Vol 12 (04) ◽  
pp. 263-267
Author(s):  
Varsha Gupta ◽  
Kritika Pal ◽  
Alisha Bhagat ◽  
Anku Goel ◽  
Jagdish Chander

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.

2011 ◽  
Vol 66 (7-8) ◽  
pp. 345-352 ◽  
Author(s):  
Rahul V. Patel ◽  
Premlata Kumari ◽  
Kishor H. Chikhalia

A series of 1,3,5-triazine derivatives that contain 4-amino-2-trifl uoromethyl-benzonitrile, 8-hydroxyquinoline, and different piperazines as substituents at the carbon atoms of the triazine ring have been synthesized by a simple and efficient synthetic protocol. The chemical structures of the compounds were elucidated with the aid of IR, 1H NMR and 13C NMR spectroscopy, and elemental analysis. The antimicrobial activity of the compounds was tested against seven bacteria (Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 619, Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 741, Klebsiella pneumoniae MTCC 109, Salmonella typhi MTCC 733, Proteus vulgaris MTCC 1771) and four fungi (Aspergillus niger MTCC 282, Aspergillus fumigatus MTCC 343, Aspergillus clavatus MTCC 1323, Candida albicans MTCC 183). The results indicate that some of the novel s-triazines have noteworthy activity in minimum inhibitory concentration as well as agar diffusion tests.


1988 ◽  
Vol 8 (4) ◽  
pp. 277-279
Author(s):  
Wendy L. Vaudry ◽  
Claudia Gratton ◽  
Kinga Kowalewska ◽  
Wanda M. Wenman

The minimum inhibitory concentration (MIC) of daptomycin was compared with that of four other antimicrobial agents against clinically relevant staphylococci. Sixtyfive isolates were obtained from patients on continuous ambulatory peritoneal dialysis (CAPD) who contracted peritonitis. These isolates comprised 29 S. Sureus strains (all sensitive to oxacillin); 25 S. epidermidis strains (14 sensitive and 9 resistant to oxacillin); and 11 unspeciated coagulase-negative staphylococci (2 sensitive and 11 resistant to oxacillin). All of the oxacillin susceptible strains were inhibited by ≤2 mg/L of the five antibiotics tested. The oxacillin resistant staphylococci were also resistant to cefuroxime and variably resistant to cefamandole, but were uniformly susceptible to both vancomycin and daptomycin. Daptomycin possesses equivalent in vitro activity to vancomycin against strains of S. Sureus and coagulase negative staphylococci associated with CAPD peritonitis. If vancomycin resistance becomes a significant problem in these patients, and daptomycin is shown to be active against vancomycin resistant organisms, then it would have potential usefulness as an alternative to vancomycin in the treatment of peritonitis caused by multiply -resistant staphylococci.


2008 ◽  
Vol 58 (4) ◽  
pp. 937-944 ◽  
Author(s):  
J. H. Cunningham ◽  
C. Cunningham ◽  
B. Van Aken ◽  
L.-S. Lin

Disinfection kinetics has been well established for selected antimicrobial agents on isolated bacterial strains. Due to the difficulties of culturing most bacteria, the majority of these studies have been limited to readily cultivable microorganisms of a single type or family. This study explores the feasibility of using flow cytometry for characterising the disinfection kinetics and minimum inhibitory concentration (MIC) of an Escherichia coli culture and a microbial consortium. The proposed method relies on fluorescent dye molecules to indicate the morphological and physiological status of numerous individual cells. Biocides of varying effectiveness and inactivation mechanisms (chlorine, iodine, and silver) were used to evaluate this novel application. Using pseudo-first-order kinetics, the coefficients of specific lethality of chlorine and iodine on Escherichia coli were 4.71 and 3.78×10−3 L mg−1 min−1 and MIC of silver ion was between 60 and 80 μg L−1. The coefficients of specific lethality of chlorine and iodine on the microbial consortium were 4.96 and 8.89×10−3 L mg−1 min−1 and MIC of silver ion was between 40 and 60 μg L−1. This method can be used to provide a rapid and consistent way of determining disinfection kinetics and MICs for pure and mixed bacterial cultures and can potentially be used to examine water and wastewater disinfection efficiency. However, caution should be used to ensure that the physiological and morphological status characterised by cytodyes is a result of the inactivation mechanisms of the disinfectants evaluated.


Author(s):  
Mohammad Hassan Moshafi ◽  
Ali Peymani ◽  
Alireza Foroumadi ◽  
Mohammad Reza Zabihi ◽  
Farzad Doostishoar

Introduction: Nitrofurans and nitroimidazoles are broad-spectrum antimicrobial agents, which affect the microbial DNA. The aim of the present study was to evaluate the new derivatives of these two groups of antimicrobials against certain Gram-positive and Gram-negative bacterial strains. Materials and Methods: Seven new derivatives of nitrofurans and nitroimidazoles were synthesized, and 6.4 mg of each derivative was dissolved in dimethyl sulfoxide. Then, 8 serial dilutions (0.5, 1, 2, 4, 8, 16, 32, and 64 μg/ml) of each derivative was prepared using Muller-Hinton broth, and the minimum inhibitory concentration for each derivative was measured and compared to ciprofloxacin (standard). Results: All the derivatives had no antibacterial effects against Gram-negative bacteria (minimum inhibitory concentration > 64 μg/ml); only 2-(5-nitro-2-furyl)-5-(n-pentylsulfunyl)-1,3,4-thiadiazole exhibited mild antibacterial effects against Klebsiella pneumonia (minimum inhibitory concentration of 16-32 μg/ml). The antibacterial effects of the derivatives against Gram-positive bacteria also showed variations from complete inhibition of the growth of Staphylococcus epidermidis and Bacillus subtilis (minimum inhibitory concentration < 0.5 μg/ml) by 2-(5-nitro-2-furyl)-5-(n-buthylthio)-1,3,4-thiadiazole to no inhibition of S. epidermidis and streptococcus pyogenes. Conclusion: These compounds have weak antibacterial effects; only two derivatives showed antibacterial effects similar to that of the positive control.


2019 ◽  
Vol 21 (2) ◽  
pp. 80-85
Author(s):  
Farshad Kakian ◽  
Behnam Zamzad ◽  
Abolfazl Gholipour ◽  
Kiarash Zamanzad

Background and aims: Klebsiella is an opportunistic organism that is the cause of severe diseases such as pneumonia, septicemia, and urinary tract infections (UTIs). In addition, high antibiotic resistance has challenged the treatment of this bacterium. However, carbapenem antibiotics are considered as the therapeutic agents for selecting the treatment of penicillin- and cephalosporin-resistant gram-negative bacterial infections. The present study aimed to determine the resistance and minimum inhibitory concentration (MIC) of meropenem and imipenem. Methods: A total of 80 Klebsiella spp isolated from UTIs were collected in various educational wards (i.e., urology, obstetrics, and gynecology, as well as the units of infectious diseases, internal medicine, and intensive care) in different hospitals of Shahrekord. The isolates were then identified by using biochemical tests. Further, disc diffusion method was employed to determine the antibiotic resistance. Furthermore, MIC was estimated by the Epsilon-test strip. Moreover, P=Q=0.50, an error of 0.05, and an accuracy of 0.11 were considered for determining the sample size (n=80). Results: Based on the results of disc diffusion method, 24 strains were resistant to meropenem and imipenem. Additionally, the MIC was 24 (30%) by the E-test. In addition, 24 isolates had a MIC of ≥4 μg/mL for meropenem and imipenem and thus were resistant while 18 isolates were found to have a MIC of 1≤ MIC<4 μg/mL and therefore, were considered semi-sensitive (P<0.001). Conclusion: In general, Klebsiella strains were found to be resistant to meropenem and imipenem. Therefore, rapid and accurate identification of these strains and the selection of appropriate antibiotics can help quickly eradicate the infections caused by these bacteria. Accordingly, a waste of time, the consumption of medication, or even an increased resistance are prevented.


2019 ◽  
Vol 21 (6) ◽  
pp. 280-283
Author(s):  
Farshad Kakian ◽  
Behnam Zamanzad ◽  
Abolfazle Gholipour ◽  
Kiarash Zamanzad

Background and aims: Carbapenems are the final-line treatments for multidrug-resistant, gram-negative infections. The patterns of resistance to carbapenems among hospital bacterial pathogens vary widely across different hospitals in a country. Considering that Escherichia coli is one of the most important causes of nosocomial infections, it is essential to study its drug resistance. Methods: In this descriptive-analytical study, a total of 80 samples of E. coli isolated from inpatients with urinary tract infections (UTIs) were collected in different wards (i.e., women, urology, infectious, and ICU) of Shahrekord hospitals. After the diagnosis and confirmation of bacteria by standard bacteriological methods, their sensitivity to imipenem and meropenem was investigated by the antibiogram (diskdiffusion) method. Then, the minimum inhibitory concentration (MIC) was determined by the E-test strip according to the Clinical and Laboratory Standards Institute (CLSI) standard. Results: In this study, resistance to meropenem and imipenem by antibiogram (disc diffusion) was observed in 21 (25.26%) and 20 (25%) of the isolates, respectively. Twenty isolates had MIC ≥4 μg/mL for meropenem, 13 isolates demonstrated MIC≥4 μg/mL for imipenem, and 14 isolates had 1≤MIC<4 μg/mL and were semi-sensitive. Conclusion: In general, E. coli had significant resistance to carbapenems. Therefore, rapid and accurate identification of these strains can be a major step to the treatment and control of these strains and prevention of the spread of the resistance.


2020 ◽  
Vol 11 (SPL2) ◽  
pp. 85-91
Author(s):  
Bhuvaneshwari G ◽  
Shameembanu A S ◽  
Kalyani Mohanram

This study was conducted with interest in increasing carbapenem resistance in non-fermenters: an important causative agent of nosocomial infection and to standardize the methods for interpretation of their resistance. The aim of this study is to perform disk diffusion testing and minimal inhibitory concentration technique for the identification of carbapenem resistance for imipenem and meropenem. The isolates found resistant to carbapenems were confirmed with the modified Hodge test. The genes responsible for carbapenem resistance were identified by both phenotypic and genotypic methods. Out of 240 non-fermenters isolated 20% showed resistance to carbapenem by disk diffusion. Only 7% showed resistance by the micro broth dilution technique of minimum inhibitory concentration. 3% were panning drug-resistant. Out of 16 carbapenem-resistant isolates, 5 were found to have KPC (Klebsiella pneumonia carbapenem) genes, 9 had MBL (Metallo beta-lactamase) genes and 2 had KPC+MBL genes and none were found to have Amp C and OXA-48 genes phenotypically. Genotypically all the KPC strains had KPC genes and out of 9 MBL strains, 6 had VIM and the remaining 3 strains were negative for both IMP and VIM gene. In conclusion, the interpretation of susceptibility for carbapenems should not be made only with disk diffusion testing. Always check for Minimal inhibitory concentration methods and determination of genes responsible for carbapenem resistance, a double-disc synergy test goes in hand with genotypic detection.


Author(s):  
Saeed Alamian ◽  
Maryam Dadar ◽  
Afshar Etemadi ◽  
Davoud Afshar ◽  
Mohammad Mehdi Alamian

Background and Objectives: Brucellosis is a widespread zoonotic disease with a high prevalence in both animals and hu- mans. The present study was aimed to evaluate the susceptibility of Brucella strains isolated from human clinical specimens against commonly used antimicrobial agents. Materials and Methods: A total of 360 blood specimens were collected during 2016-2018 and subjected to culture and Brucella spp. identification. The classical biotyping for Brucella isolates was performed according to Alton and coworker's guidelines. Antimicrobials susceptibility test carried out using disk diffusion and minimal inhibitory concentration (MIC) methods. Results: In this study, sixty B. melitensis strains were isolated from blood samples (16%) and all them belonged to biovar 1. Majority of the tested antibacterial agents, excepting ampicillin-sulbactam had an effective activity against B. melitensis isolates in E-test (MIC) and disk diffusion method. Moreover, probable resistance to rifampin and ampicillin-sulbactam were observed in 60 (100%), 1 (1.7%), 11 (18.4%) and 2 (3.4%) isolates, respectively. Conclusion: Our data suggest that the efficacy of commonly used antibiotics for brucellosis treatment should be regularly monitored. In conclusion, appropriate precaution should be exercised in the context of antibiotic administration to prevent future antibiotic resistance.


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