Disk Diffusion Method
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2022 ◽  
Vol 8 ◽  
Shuzhen Xiao ◽  
Chenyue Tang ◽  
Qian Zeng ◽  
Yilun Xue ◽  
Qing Chen ◽  

Background: Bloodstream infections are recognized as important nosocomial infections. Escherichia coli (E. coli) is the most prevalent Gram-negative bacillary pathogen causing bloodstream infections (BSIs). This retrospective study investigated drug susceptibility and molecular epidemiology of E. coli isolated from patients with BSI in Shanghai, China.Methods: We collected E. coli isolated from the blood cultures of patients with BSI between January 2016 and December 2019. We randomly selected 20 strains each year to investigate antimicrobial resistance, resistance genes, and molecular epidemiological characteristics. Antimicrobial susceptibility testing was performed by the disk diffusion method. PCR was performed to detect extended-spectrum β-lactamases (ESBLs), carbapenemase genes, and housekeeping genes, and phyloviz was applied to analyze multilocus sequence typing (MLST).Results: Penicillins, first- and second-generation cephalosporins and fluoroquinolones have high resistance rates (>60%). Among the 80 randomly selected strains, 47 (58.8%) produced ESBLs, and one produced carbapenemase. Sequencing of resistance genes identified blaCTX−M−14 (34%, 16/47), blaCTX−M−15 (23.4%, 11/47) and blaCTX−M−27 (14.8%, 7/47) as the most prevalent genotypes of ESBLs. ST131 (14/80) was the most prevalent sequence type (ST), followed by ST1193 (10/80), ST648 (7/80).Conclusions: Our findings suggest that amikacin, carbapenems, and piperacillin-tazobactam have relatively low resistance rates and may be the preferred antibiotic regimens for empiric therapy. ST131 and blaCTX−M−14 are still the main prevalent in Shanghai with a rapid increase in the occurrence of ST1193 is rapidly increasing and more diverse blaCTX genes.

2022 ◽  
Vol 21 (1) ◽  
pp. 84-89
Fitri A Nurani ◽  
Nadia RS Rejeki ◽  
Tanti Setyoputri ◽  
Putri K Wardani ◽  
Fatkhan B Ridwan ◽  

Introduction: Corn silk or known as herb name stigma maydis is an important medicinal botanical in many traditional medicines worldwide, including jamu, an Indonesia traditional medicine. The exploration of corn silk to treat acne vulgaris is still lacking, therefore the current research was conducted to analyze the activity of ethanolic extract from corn silk (EECS) against 3 acne-related bacteria, Propionibacterium acnes, Staphylococcus epidermidis and Staphylococcus aureus. Materials and Methods: The antibacterial activity of EECS at concentration range of 10 to 100% v/v was evaluated using the disk diffusion method. As comparation, distilled water was used as a solvent control, while 1% clindamycin was used as a positive control. Results: Shinoda’s test showed that flavonoid was detected in the EECS. The higher concentration of EECS exhibited higher diameter of inhibition zone indicating higher antibacterial activity on P. acnes, while the antibacterial activity of S. epidermidis was not increased at similar concentrations of EECS. The antibacterial activity of EECS against S. aureus decreased at the higher EECS concentration (>70%). Conclusion: Taken together, EECS is a potential as a bioactive source to inhibit the growth of acne-related bacteria P. acne, S. epidermidis and S. aureus. Further investigation is needed to explore the corn silk or stigma maydis as a medicinal botanical in jamu targeted to treat acne vulgaris. Bangladesh Journal of Medical Science Vol. 21(1) 2022 Page : 84-89

2021 ◽  
Vol 7 (3) ◽  
pp. 227-233
Dwi Lestari ◽  
Desy Fitriani ◽  
Serli Anngraeni

Kasturi mango (Mangifera casturi Kosterm.) is a typical mango of South Kalimantan. Kasturi mango leaves are reported to have antioxidant activity and are potential for treating various diseases, including diseases related to antibacterial. This study examines the antibacterial activity of ethyl acetate fraction and the n-hexane fraction of mango musk leaves on bacteria that cause acne. Experimental research started with plant determination, making extracts and fractions, phytochemical screening, and antibacterial testing against Staphylococcus aureus and Propionibacterium acnes using the disk diffusion method. The study results found that the ethyl acetate and n-hexane fractions had weak antibacterial activity against S. aureus and P. acnes bacteria, which cause acne

2021 ◽  
Vol 26 (6) ◽  
pp. 3090-3094

Objective: the isolation and phenotypically identification of a Gallibacterium anatis biovar haemolytica strain from a hen with hemorrhagic ooforitis; the antimicrobial susceptibility testing of this isolate. Methods and results: a strain of G. anatis biovar haemolytica, was isolated and phenotypic identified by morphological, cultural and biochemical characters examination, with API 20 E, API 20 NE, API STAPH, API ZYM tests and ABIS online software. The antimicrobial susceptibility of the isolate was performed using the standard disk diffusion method. Conclusions: a strain of G. anatis biovar haemolytica was isolated and phenotypically identified from a hen. From our knowledge, this is the first reporting in Romania of isolation and identification of G. anatis biovar haemolytica. The Gah IDSA 161 strain could be phenotypic identified only by ABIS on line software, Pasteurellaceae Database version, unifying the results of four API kits and other biochemical tests. The isolate showed a multi-drug resistant profile to tetracyclines (tetracycline, oxitetracycline, doxicyclin), floroquinolones (enrofloxacin, ciprofloxacin), ampicillin, trimethoprim, nalidixic acid, clindamycin, and it was susceptible to sulfonamide, sulfomethoxazole/trimethoprim, gentamicin, cephalothin, streptomycin, amoxicilin/clavulanic acid.

2021 ◽  
Vol 9 (1) ◽  
pp. 12
Walid Oueslati ◽  
Mohamed Ridha Rjeibi ◽  
Hayet Benyedem ◽  
Aymen Mamlouk ◽  
Fatma Souissi ◽  

This study was conducted in northeastern Tunisia to estimate both the prevalence and the risk factors of Salmonella in broiler flocks as well as to characterize the isolated multidrug-resistant (MDR) Salmonella strains. In the present study, a total number of 124 farms were sampled; Salmonella isolates were identified by the alternative technique VIDAS Easy Salmonella. The susceptibility of Salmonella isolates was assessed against 21 antimicrobials using the disk diffusion method on Mueller–Hinton agar using antimicrobial discs. Some antimicrobial resistance genes were identified using PCR. The prevalence rate of Salmonella infection, in the sampled farms, was estimated at 19.9% (64/322). Moreover, a total number of 13 different serotypes were identified. High rate of resistance was identified against nalidixic acid (82.85%), amoxicillin (81.25%), streptomycin (75%), and ciprofloxacin (75%). Alarming level of resistance to ertapenem (12.5%) was noticed. A total of 87.5% (56/64) of isolated strains were recognized as MDR. Three MDR strains were extended-spectrum β-lactamases (ESBL)-producers and three MDR strains were cephalosporinase-producers. The blaCTX-M gene was amplified in all the three ESBL strains. The qnrB gene was not amplified in fluoroquinolones-resistant strains. The tetA and tetB genes were amplified in 5% (2/40) and 2.5% (1/40) of tetracycline-resistant strains, respectively. The dfrA1 gene was amplified in five of the 20 trimethoprim-resistant strains. The mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5 genes were not amplified in any of the phenotypically colistin-resistant strains. In terms of integrase genes int1 and int2, only gene class 2 was amplified in 11% (7/64) of analyzed strains. Risk factors, such as the poor level of cleaning and disinfection, the lack of antimicrobial treatment at the start of the breeding, and a crawl space duration lower than 15 days, were associated with high Salmonella infection in birds. These data should be considered when preparing salmonellosis control programs in Tunisian broiler flocks.

2021 ◽  
pp. 3216-3223
Thuan K. Nguyen ◽  
Lam T. Nguyen ◽  
Trang T. H. Chau ◽  
Tam T. Nguyen ◽  
Bich N. Tran ◽  

Background and Aim: Salmonella is one of the leading causes of zoonotic and foodborne infectious outbreaks in humans and poultry and its associated environment is a potential reservoir of Salmonella. In recent years, the antibiotic resistance of bacteria, including Salmonella, has been increasing. This study aimed to investigate the prevalence and antibiotic resistance of Salmonella isolated from poultry, its environment, and the pest animals found at poultry farms and households of the Mekong Delta, Vietnam. Materials and Methods: A total of 3,055 samples were collected from the broiler farms and households of the Mekong Delta from 2017 to 2020. Salmonella was isolated using conventional methods (culturing on selective agar – BPLS and biochemical test) and the isolates were examined for antibiotic resistance against 14 antibiotics using the disk diffusion method. Results: Salmonella was isolated from 181 samples (5.92%), which included chicken feces (7.67%), pest animals (5.98%), and environmental samples (4.33%). The environmental samples comprised bedding (5.88%), feed (5.48%), and drinking water (0.70%). The prevalence of Salmonella was the highest in rats (15.63%) and geckos (12.25%) followed by ants (2.83%) and cockroaches (2.44%); however, Salmonella was not isolated from any fly species. Most of the isolates exhibited resistance to 1-9 antibiotics. The isolates were relatively resistant to chloramphenicol (62.98%), tetracycline (55.80%), ampicillin (54.14%), and sulfamethoxazole/trimethoprim (53.04%). Sixty-two multiple resistance patterns were found in the isolates, with ampicillin-cefuroxime-chloramphenicol-tetracycline- sulfamethoxazole/trimethoprim being the most frequent (7.18%). Conclusion: The chickens, husbandry environment, and pest animals at poultry farms and households were found to be important Salmonella sources in the Mekong Delta. Salmonella isolates from these sources also exhibited a wide-ranging resistance to antibiotics as well as several resistance patterns. Hence, biosecurity should be addressed in poultry farms and households to prevent cross-contamination and reduce the spread of Salmonella infections.

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Omid Zarei ◽  
Leili Shokoohizadeh ◽  
Hadi Hossainpour ◽  
Mohammad Yousef Alikhani

Background. Shiga toxin-producing Escherichia coli (STEC) is known as a crucial zoonotic food-borne pathogen. A total of 257 raw chicken meat samples were collected from different markets in Hamadan, west of Iran, from January 2016 to May 2017. Materials and Methods. The samples were cultured in selective and differential culture media, and the virulence genes of E. coli isolates were analyzed by PCR assay. The antibiotic resistance patterns of E. coli isolates were determined by the disk diffusion method. The genetic relatedness of the E. coli O157 isolates was analyzed by ERIC-PCR. Results. In total, 93 (36% ± 3.12) of the isolates were identified as E. coli in this study. Based on serological and microbiological tests, 36 (38.7% ± 9.9), 7 (7.5% ± 5.35), and 12 (12.9% ± 6.81) of the E. coli isolates were characterized as STEC, enteropathogenic E. coli (EPEC), and attaching and effacing E. coli (AEEC) strains, respectively. A high level of resistance to nalidixic acid (91.4% ± 5.7), tetracycline (89.2% ± 6.31), ampicillin (82.8% ± 7.67), and trimotoprime-sulfametoxazole (71% ± 9.22) was detected among the E. coli isolates. The analysis of the ERIC-PCR results showed five different ERIC types among the E. coli O157 isolates. Conclusions. Based on our findings, control and check-up of poultry meats should be considered as a crucial issue for public health.

Biomimetics ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 4
Simin Sharifi ◽  
Asma Zaheri Khosroshahi ◽  
Solmaz Maleki Dizaj ◽  
Yashar Rezaei

In this study, we prepared and evaluated hydroxyapatite–gelatin/curcumin nanofibrous composites and determined their antimicrobial effects against Escherichia coli, Staphylococcus aureus, and Streptococcus mutans. Hydroxyapatite–gelatin/curcumin nanofibrous composites were prepared by the electrospinning method. The prepared nanocomposites were then subjected to physicochemical studies by the light scattering method for their particle size, Fourier transmission infrared spectroscopy (FTIR) to identify their functional groups, X-ray diffraction (XRD) to study their crystallinity, and scanning electron microscopy (SEM) to study their morphology. For the microbial evaluation of nanocomposites, the disk diffusion method was used against Streptococcus mutans, Staphylococcus aureus, and Escherichia coli. The results showed that the nanofibers were uniform in shape without any bead (structural defects). The release pattern of curcumin from the nanocomposite was a two-stage release, 60% of which was released in the first two days and the rest being slowly released until the 14th day. The results of the microbial evaluations showed that the nanocomposites had significant antimicrobial effects against all bacteria (p = 0.0086). It seems that these nanocomposites can be used in dental tissue engineering or as other dental materials. Also, according to the appropriate microbial results, these plant antimicrobials can be used instead of chemical antimicrobials, or along with them, to reduce bacterial resistance.

2021 ◽  
Vol 5 (4) ◽  
pp. 375-380
Ayu Nala El Muna Haerussana ◽  
Wulan Putri Dwiastuti ◽  
Cindi Arwan Sukowati

Indonesia has a high diversity of potential medicinal plants, which are the second-largest number of indigenous medicinal plants in the world. Syzygium polyanthum, known as Indonesian Bay Leaf or Salam, easily found, widely used in Indonesia as a spice in cooking and traditional medicine. Salam contains secondary metabolites such as flavonoids, alkaloids, tannins, essential oils, sesquiterpenes, triterpenes, phenols, steroids, and saponins. Staphylococcus aureus and Staphylococcus epidermidis are the main bacteria that cause commensal infection and the most common nosocomial infections. This study aims to know the antibacterial activity of the Salam ethanolic extract against Staphylococcus aureusand Staphylococcus epidermidis bacteria. Salam leaves were extracted by 70% ethanol in the maceration method. Antibacterial activity was conducted by the disk diffusion method. The extract exhibits moderate activity (10.51±0.3 mm) at 75% of concentration and low activity (3.69±0.4 mm) at 100% of concentration against Staphylococcus aureus and Staphylococcus epidermidis respectively. The test showed that salam leaves extract had antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis.

Nova ◽  
2021 ◽  
Vol 19 (37) ◽  
pp. 121-134
Lidia Po Catalao Dionisio ◽  
Alejandro Manuel Labella ◽  
María Palma ◽  
Juan José Borrego

Aim. In vitro antimicrobial activities of seven wines (5 reds and 2 whites) from the Douro region (Iberian Peninsule) against eleven clinical strains of Helicobacter pylori were evaluated. Methods. The disk diffusion method, using Columbia Agar supplemented with horse blood (CAB), were used to determine the antimicrobial properties of some wine components against H. pylori strains. Potential interactions of antioxidants contained in the wines and two antimicrobials (amoxicillin and metronidazole) were studied by the disk diffusion method. Results. All the tested strains showed growth in CAB supplemented with 9% of the tested wines but none of them grew in media supplemented with 45% and 67.5% of wine. Similarly, all the tested strains grew in media with the concentration of proanthocyanidins present in the different types of the studied wines. The Minimal Inhibitory Concentration (MIC) values of the wine antioxidant components tested (benzoic acid, catechin, quercetin, and resveratrol) indicate that resveratrol was the most powerful inhibitory substance against H. pylori. An effect of potentiation between amoxicillin and metronidazole and the antioxidants tested was also established. The interaction of amoxicillin and resveratrol or metronidazole and catechin increased the antimicrobial activity against H. pylori. Conclusions. The results obtained suggested a potential role of resveratrol as a chemopreventive agent for H. pylori infection.

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