scholarly journals In Vitro comparison in the antimicrobial effect between Ciprofloxacin and Neem leaf extract (Azadirachta indica) on Escherichia coli Growth

2016 ◽  
Vol 15 (2) ◽  
pp. 172-177
Author(s):  
Quazi Rubyath Banna ◽  
Badar Uddin Umar ◽  
S M Niazur Rahman ◽  
Tanbira Alam ◽  
Kazi Selim Anwar ◽  
...  

Objective: Medicinal plants remain in vogue to treat some diseases in lower socio-economic communities, despite the availability of antimicrobials, often. Majority of rural Bangladeshi and tribal people being grossly illiterate and ignorant, use various herbs to treat a wide range of diseases. Of several medicinal-plants, neem is reported to have enormous impact in treating inflammation and infections. We, therefore, compared the antimicrobial effect of ethanolic neem leave extract (ENLE) on Escherichia coli (E. coli), with that of Ciprofloxacin. Materials & Methods: This experimental study compared the in vitro antimicrobial activity between ENLE and Ciprofloxacin on E. coli carried out in Department of Pharmacology and Therapeutics of SS-Medical College, Dhaka, Bangladesh. Antimicrobial efficacy of ENLE and ciprofloxacin (5µg; Oxoid, UK) was determined against E. coli following minimum inhibitory concentration. By filtration and evaporation of Neem leaves ENLE was prepared. Antibiotic Sensitivity Test was performed on Muller-Hinton agar using a twofold serial dilution. Results: ENLE showed an inhibitory effect on the growth of E. coli at the concentration of 3.125 mg/ml. Antibacterial susceptibility of E. coli was performed on MHA and diameters of zone of inhibition by both ENLE and Ciprofloxacin were measured after overnight aerobic incubation at 37°C. Diameter of zone of inhibition against E. coli was 28 ± 0.16 mm with ENLE, 36 ± 0.07 mm with Ciprofloxacin (5µg/disk) (p<0.000). Conclusion: Findings of this preliminary in-vitro experiment though suggests that, ENLE against E. coli showed limited efficacy, better efficacy of Ciprofloxacin cannot be ruled out unless further in depth studies elucidates stronger evidences to support it.Bangladesh Journal of Medical Science Vol.15(2) 2016 p.172-177

2019 ◽  
Vol 24 ◽  
pp. 2515690X1988627 ◽  
Author(s):  
Mekonnen Sisay ◽  
Negussie Bussa ◽  
Tigist Gashaw ◽  
Getnet Mengistu

Medicinal plants are targeted in the search for new antimicrobial agents. Nowadays, there is an alarmingly increasing antimicrobial resistance to available agents with a very slow development of new antimicrobials. It is, therefore, necessary to extensively search for new agents based on the traditional use of herbal medicines as potential source. The antibacterial activity of 80% methanol extracts of the leaves of Verbena officinalis (Vo-80ME), Myrtus communis (Mc-80ME), and Melilotus elegans (Me-80ME) was tested against 6 bacterial isolates using agar well diffusion technique. In each extract, 3 concentrations of 10, 20, and 40 mg/well were tested for each bacterium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Vo-80ME and Mc-80ME exhibited promising antibacterial activity against Staphylococcus aureus with the highest zone of inhibition being 18.67 and 26.16 mm, respectively at concentration of 40 mg/well. Regarding gram-negative bacteria, Vo-80ME exhibited an appreciable activity against Escherichia coli and Salmonella typhi. Mc-80ME displayed remarkable activity against all isolates including Pseudomonas aeruginosa with the maximum zone of inhibition being 22.83 mm. Me-80ME exhibited better antibacterial activity against E coli, but its secondary metabolites had little or no activity against other gram-negative isolates. The MIC values of Vo-80ME ranged from 0.16 to 4.00 mg/mL. The lowest MIC was observed in Mc-80ME, with the value being 0.032 mg/mL. Mc-80ME had bactericidal activity against all tested bacterial isolates. Mc-80ME showed remarkable zone of inhibitions in all tested bacterial isolates. Besides, Vo-80ME showed good antibacterial activity against S aureus, E coli, and S typhi. Conversely, Me-80ME has shown good activity against E coli only. Generally, M communis L and V officinalis have good MIC and MBC results.


2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Erin M. Nawrocki ◽  
Hillary M. Mosso ◽  
Edward G. Dudley

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) strains, including E. coli O157:H7, cause severe illness in humans due to the production of Shiga toxin (Stx) and other virulence factors. Because Stx is coregulated with lambdoid prophage induction, its expression is especially susceptible to environmental cues. Infections with Stx-producing E. coli can be difficult to model due to the wide range of disease outcomes: some infections are relatively mild, while others have serious complications. Probiotic organisms, members of the gut microbiome, and organic acids can depress Stx production, in many cases by inhibiting the growth of EHEC strains. On the other hand, the factors currently known to amplify Stx act via their effect on the stx-converting phage. Here, we characterize two interactive mechanisms that increase Stx production by O157:H7 strains: first, direct interactions with phage-susceptible E. coli, and second, indirect amplification by secreted factors. Infection of susceptible strains by the stx-converting phage can expand the Stx-producing population in a human or animal host, and phage infection has been shown to modulate virulence in vitro and in vivo. Acellular factors, particularly colicins and microcins, can kill O157:H7 cells but may also trigger Stx expression in the process. Colicins, microcins, and other bacteriocins have diverse cellular targets, and many such molecules remain uncharacterized. The identification of additional Stx-amplifying microbial interactions will improve our understanding of E. coli O157:H7 infections and help elucidate the intricate regulation of pathogenicity in EHEC strains.


2020 ◽  
Vol 14 (3) ◽  
pp. 1855-1861
Author(s):  
Isra Tayseer ◽  
Hanan Azzam ◽  
Nehaya Al-Karablieh ◽  
Amal Mayyas ◽  
Talal Aburjai

The present study was conducted to assess the in vitro activities of folk medicinal plants in combination with levofloxacin against TG1 and mutant KAM3-1(∆acrB-∆tolC) Escherichia coli strains. Plants were chosen based on their traditional use in combination with antibiotics among laymen. Standard protocols were followed to examine the antimicrobial activity of plant extracts and levofloxacin against E. coli in term of their minimum inhibitory concentrations (MICs) and to evaluate the plant extracts-levofloxacin interaction using checkerboard method. Among the twelve plants investigated, Thymus vulgaris, Zingiber officinale, Teucrium polium, Matricaria chamomilla and Curcuma longa had the best antimicrobial activities against E. coli strains with MIC values at 250 μg/ml. It is noteworthy to mention that other folk plants extracts reveled no effects against E coli strains. Furthermore, additive interactions were observed between levofloxacin and T. polium or T. vulgaris against E. coli wild-type TG1 strain. There was no antagonism being observed in this study. The detection of additive interaction between the extracts and levofloxacin demonstrates the prospective of these folk medicinal plants as a source of compounds to modulate antibiotic resistance.


1999 ◽  
Vol 43 (3) ◽  
pp. 498-502 ◽  
Author(s):  
Alexander A. Firsov ◽  
Sergey N. Vostrov ◽  
Olga V. Kononenko ◽  
Stephen H. Zinner ◽  
Yury A. Portnoy

ABSTRACT The effect of inoculum size (N 0) on antimicrobial action has not been extensively studied in in vitro dynamic models. To investigate this effect and its predictability, killing and regrowth kinetics of Staphylococcus aureus andEscherichia coli exposed to monoexponentially decreasing concentrations of trovafloxacin (as a single dose) and ciprofloxacin (two doses at a 12-h interval) were compared atN 0 = 106 and 109 CFU/ml (S. aureus) and at N 0 = 106, 107, and 109 CFU/ml (E. coli). A series of pharmacokinetic profiles of trovafloxacin and ciprofloxacin with respective half-lives of 9.2 and 4 h were simulated at different ratios of area under the concentration-time curve (AUC) to MIC (in [micrograms × hours/milliliter]/[micrograms/milliliter]): 58 to 466 with trovafloxacin and 116 to 932 with ciprofloxacin for S. aureus and 58 to 233 and 116 to 466 for E. coli, respectively. Although the effect of N 0 was more pronounced for E. coli than for S. aureus, only a minor increase in minimum numbers of surviving bacteria and an almost negligible delay in their regrowth were associated with an increase of the N 0 for both organisms. TheN 0-induced reductions of the intensity of the antimicrobial effect (IE , area between control growth and the killing-regrowth curves) were also relatively small. However, the N 0 effect could not be eliminated either by simple shifting of the time-kill curves obtained at higherN 0s by the difference between the higher and lowest N 0 or by operating withIE s determined within theN 0-adopted upper limits of bacterial numbers (IE ′s). By using multivariate correlation and regression analyses, linear relationships betweenIE and log AUC/MIC and logN 0 related to the respective mean values [(log AUC/MIC)average and (logN 0)average] were established for both trovafloxacin and ciprofloxacin against each of the strains (r 2 = 0.97 to 0.99). The antimicrobial effect may be accurately predicted at a given AUC/MIC of trovafloxacin or ciprofloxacin and at a given N 0 based on the relationship IE = a + b [(log AUC/MIC)/(log AUC/MIC)average] − c [(logN 0)/(logN 0)average]. Moreover, the relative impacts of AUC/MIC and N 0 onIE may be evaluated. Since the c/bratios for trovafloxacin and ciprofloxacin against E. coliwere much lower (0.3 to 0.4) than that for ampicillin-sulbactam as examined previously (1.9), the inoculum effect with the quinolones may be much less pronounced than with the β-lactams. The described approach to the analysis of the inoculum effect in in vitro dynamic models might be useful in studies with other antibiotic classes.


2019 ◽  
Vol 50 (3) ◽  
pp. 433-442
Author(s):  
Kamilla Soares Silva ◽  
Letícia Fleury Viana ◽  
Bruna Ariel Dias Guariglia ◽  
João Paulo Soares ◽  
Lismaíra Gonçalves Caixeta Garcia ◽  
...  

Purpose The growing consumer demand for microbiologically safe and quality products with sensory properties similar to those of natural products has spurred the search for natural flavourings with an antimicrobial effect on foods. The purpose of the present study is to evaluate the in vitro antimicrobial activity of “malagueta” chili pepper and “dedo de moça” hot pepper on Minas Frescal cheese supplemented with Escherichia coli strains. Design/methodology/approach Each cheese contained 0, 10, 15 and 20 per cent concentrations of “malagueta” chilli pepper and “dedo de moça” hot pepper supplemented with 200 µL of E. coli/kg cheese. The cheeses were stored under refrigeration at 7 °C for 28 days. The E. coli, pH and titratable acidity were analysed for this cheese. Findings “Dedo de moça” hot pepper showed a bacteriostatic effect on E. coli strains being more efficient on day 1. However, the “malagueta” hot pepper showed bactericidal effect and was efficient during the 28 days of storage. The pH showed a gradual decrease (p = 0.000) throughout the storage period; therefore, the acidity was increased even when the CFU/g count remained constant. The peppers had an antimicrobial effect on E. coli strains, and thus might be an alternative to extend the shelf life of Minas frescal cheese. Originality/value The study of natural condiments as an antimicrobial alternative is important because they prevent infections and food infections, increase shelf life and make it possible to offer differentiated products in the market.


2021 ◽  
Vol 39 (1) ◽  
pp. 20
Author(s):  
Maria Fatima Palupi ◽  
Eli Nugraha ◽  
Meutia Hayati ◽  
Neneng Atikah

Mutant prevention concentration (MPC) is an in vitro test used to determine the lowest drug concentration needed to inhibit the growth of a single-step-mutant bacterial subpopulation. The purpose of this study was to determine the MPC value of ciprofloxacin against pathogenic Escherichia coli to obtained the range of mutant selection windows (MSW) of ciprofloxacin. Ciprofloxacin is a quinolone group that is included in the Highest Priority Critically Important Antimicrobials for Human Medicine but is also used for the treatment of bacterial infections in production animals. Twenty-four of pathogenic E. coli isolates sensitive to ciprofloxacin were tested to obtain MPC values and minimum inhibitory concentration (MIC) values. Test the MPC and MIC values to get the MSW range is done by the method of agar dilution. Mueller-Hinton agar containing standard ciprofloxacin was inoculated with 1010 cfu E. coli for the MPC test and 104 for the MIC test. Based on the MPC test results, the MPC value of ciprofloxacin was 4-64 μg / mL (22.96 ± 19.07 μg / mL) and there was one isolate which had an MPC> 256 μg / mL. These results give a wide range of MSW with a lower limit of the MIC value of 0.25 - 2 µg / mL (0.55 ± 0.37 µg / mL) to the upper limit of the MPC value of 4-64 µg / mL (22.96 ± 19.07 μg / mL). Based on the results of this MPC assessment it can be concluded that the dose of ciprofloxacin in production animals has a wide range of MSW that is allow for single-step mutants.


Antibiotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 74 ◽  
Author(s):  
Yen-Te Liao ◽  
Alexandra Salvador ◽  
Leslie A. Harden ◽  
Fang Liu ◽  
Valerie M. Lavenburg ◽  
...  

Shiga toxin-producing Escherichia coli (STEC) O145 is one of the most prevalent non-O157 serogroups associated with foodborne outbreaks. Lytic phages are a potential alternative to antibiotics in combatting bacterial pathogens. In this study, we characterized a Siphoviridae phage lytic against STEC O145 strains as a novel antimicrobial agent. Escherichia phage vB_EcoS-Ro145clw (Ro145clw) was isolated and purified prior to physiological and genomic characterization. Then, in vitro antimicrobial activity against an outbreak strain, E. coli O145:H28, was evaluated. Ro145clw is a double-stranded DNA phage with a genome 42,031 bp in length. Of the 67 genes identified in the genome, 21 were annotated with functional proteins, none of which were stx genes. Ro145clw had a latent period of 21 min and a burst size of 192 phages per infected cell. The phage could sustain a wide range of pH (pH 3 to pH 10) and temperatures (−80 °C to −73 °C). Ro145clw was able to reduce E. coli O145:H28 in lysogeny broth by approximately 5 log at 37 °C in four hours. These findings indicate that the Ro145clw phage is a promising antimicrobial agent that can be used to control E. coli O145 in adverse pH and temperature conditions.


2000 ◽  
Vol 63 (5) ◽  
pp. 601-607 ◽  
Author(s):  
CATHERINE N. CUTTER

The effects of plant extracts against pathogenic bacteria in vitro are well known, yet few studies have addressed the effects of these compounds against pathogens associated with muscle foods. A series of experiments was conducted to determine the effectiveness of a commercially available, generally recognized as safe, herb extract dispersed in sodium citrate (Protecta One) or sodium chloride (Protecta Two) against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes associated with beef. In the first experiment, E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes inoculated onto beef and subjected to surface spray treatments with 2.5% solutions of Protecta One or Protecta Two were not affected by immediate application (day 0) of the herbal extracts. However, after 7 days of storage at 4°C, E. coli O157:H7 was reduced by &gt;1.3 log10 CFU/cm2 by Protecta Two; L. monocytogenes was reduced by 1.8 and 1.9 log10 CFU/cm2 by Protecta One and Protecta Two, respectively; Salmonella Typhimurium was not reduced &gt;0.3 log10 CFU/cm2 by either extract by day 7. In the second experiment, 2.5% Protecta Two (wt/vol or wt/wt) added to inoculated lean and adipose beef trim, processed, and packaged as ground beef chubs (80% lean, 20% adipose), did not reduce pathogen populations &gt;0.5 log10 CFU/g up to 14 days at 4°C. In the third experiment, surface spray treatments of beef with 2.5% lactic acid or 2.5% solutions of Protecta One or Protecta Two, vacuum packaged, and stored up to 35 days at 4°C did reduce E. coli O157:H7, L. monocytogenes, and Salmonella Typhimurium slightly. These studies suggest that the use of herb extracts may afford some reductions of pathogens on beef surfaces; however, the antimicrobial activity may be diminished in ground beef by adipose components.


2018 ◽  
Vol 55 (4) ◽  
pp. 390-396 ◽  
Author(s):  
Roger Lafontaine Mesquita TABORDA ◽  
Luiz Antônio da SILVA ◽  
Patricia Puccinelli ORLANDI ◽  
Flávia Serrano BATISTA ◽  
Renata Santos RODRIGUES ◽  
...  

ABSTRACT BACKGROUND: Enteroaggregative Escherichia coli (EAEC) is one of the main acute and chronic diarrhea causes both in children and adults, mainly in developing countries. OBJECTIVE: The aim of the present study is to characterize EAEC strains isolated from faecal samples and to identify genes potentially contributing to virulence, biofilm production and antimicrobial resistance in children admitted to a pediatric hospital in Porto Velho, Rondônia State. METHODS: The total of 1,625 E. coli specimens were isolated from 591 children in the age group 6 years or younger who were hospitalized in Cosme and Damião Children Hospital in Porto Velho, between February 2010 and February 2012, with acute gastroenteritis. Colonies suggestive of E. coli were subjected to polymerase chain reaction testing in order to identify the virulence factors. The in vitro adhesion assays using HEp-2 adherence were tests. Biofilm detection through spectrophotometry and antimicrobial susceptibility tests were conducted in the disk diffusion method. RESULTS: The mentioned study examined 591 stool samples from children with diarrhea. Diarrheogenic E. coli was found in 27.4% (162/591) of the children. EAEC was the diarreagenic E. coli most frequently associated with diarrhea 52.4% (85/162), which was followed by enteropathogenic E. coli 43.8% (71/162), enterotoxigenic E. coli 2.4% (4/162), and enterohemorrhagic E. coli 1.2% (2/162). The aggR gene was detected in 63.5% (54/85) of EAEC isolates; moreover, statistically significant correlation was observed among typical EAEC (aggR) and aatA (P<0.0001), irp2 (P=0.0357) and shf (P=0.0328). It was recorded that 69% (59/85) of the 85 analyzed EAEC strains were biofilm producers; 73% (43/59) of the biofilm producers carried the aggR gene versus 42.3% (11/26) of non-producers (P=0.0135). In addition, there was association between the aatA gene and biofilm production; 61% (36/59) of the samples presented producer strains, versus 19.2% (5/26) of non-producers (P<0.0004). Antibiotic sensitivity test evidenced that most EAEC were ampicillin 70.6% (60/85), sulfamethoxazole 60% (51/85), tetracycline 44.7% (38/85) and cefotaxime 22.4% (19/85) resistant. CONCLUSION: As far as it is known, the present study is pioneer in Northern Brazil to investigate EAEC virulence factors and to show the antimicrobial susceptibility of EAEC strains isolated from children with diarrhea.


1970 ◽  
Vol 1 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Tanvir Bashar ◽  
Mostafizur Rahman ◽  
Fazle Alam Rabbi ◽  
Rashed Noor ◽  
M Majibur Rahman

Bacterial diseases remain a threat to the poultry industry and countermeasures to prevent and control them are needed to prevent production losses. With the continued threat of exotic and emerging diseases and the problem of the use of antibiotics in animal production, there is a serious and urgent need to find safe and practical alternatives to prevent or control pathogens. That,s why, our research has addressed in different poultry farms for detection of toxigenic Escherichia coli from poultry chicken feces adjacent to the Dhaka city, during the period of January 2009 to June 2009 and characterize their ability to produce enterotoxin and also examined the antibiogram of the isolates. A total of 60 fecal samples were collected and E. coli were isolated and identified by conventional cultural, biochemical and motility test.The heatstable toxins were determined by Suckling Mice Assay (SMA). The overall prevalence of E. coli was 100%. Among the isolates of E. coli, only 45% and 14% isolates showed β hemolysis and α hemolysis, respectively. Congo red binding has been used as a potential virulence marker and 69 % E. coli isolates in the present study showed congo red binder, among which, 59% isolates were hemolytic. A total of 20% and 5% isolates showed the presence of LT and ST enterotoxin in their guts by Suckling Mice assay, respectively. The antibiotic sensitivity pattern shown that the isolates were highly sensitive (100%) to imipenem, pipercillin, neomycin and ceftrixone. Results from this study revealed the high prevalence rate of E. coli isolates with variable resistance against a wide range of antimicrobial drug. It may suggest that the high resistance of E. coli to antibiotics as well as their toxigenic nature constitutes a threat not only to poultry industry of Bangladesh but also possesses a serious threat to public and animal health. DOI: http://dx.doi.org/10.3329/sjm.v1i1.9134   Stamford Journal of Microbiology, Vol.1(1), July 2011, p.51-57


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