Showing 66 results for Bacteria
Azizollah Ebrahimi , Azimeh Babaaie , Mojtaba Boniadian , Sharareh Lotfalian ,
Volume 13, Issue 3 (5-2019)
Abstract
ABSTRACT
Background and Objectives: Efflux-based systems may play a role in resistance to fluoroquinolones in Gram-negative pathogenic bacteria. Extracts of some medicinal plants contain molecules that can act as efflux pumps inhibitors. In this study, we aimed to evaluate antibacterial activities of ethanolic and chloroform extracts of Cinnamomum zeylanicum and their possible synergistic activity with ciprofloxacin against some Gram-negative pathogenic bacteria. We also analyzed the extracts for presence of efflux pump inhibitors against the examined bacteria.
Methods: Powdered dried leaves and branches of C. zeylanicum were extracted with ethanol (85%) and chloroform by the maceration method. Minimum inhibitory concentrations of the extracts alone or combined with ciprofloxacin and phenylalanine-arginine β-naphthylamide (an efflux pump inhibitor) were determined against Pseudomonas aeruginosa, Acinetobacter bummani, Escherichia coli and Salmonella enteritidis using the double serial microdilution method.
Results: The extracts of C. zeylanicum inhibited the growth of all studied bacteria. Synergistic effects were noted between the extracts and ciprofloxacin against all tested bacteria other than P. aeruginosa. Ciprofloxacin efflux pumps in E. coli, S. enteritiditis and A. baumannii were inhibited by the extracts of C. zeylanicum.
Conclusion: The extracts of C. zeylanicum could be used as ciprofloxacin-potentiating agents against some Gram-negative pathogens.
Keywords: Anti-bacterial agents, Cinnamomum zeylanicum, Bacterial pathogens, Efflux pumps.
Mohsen Mousavi , Behrooz Johari , Jamil Zargan , Ashkan Haji Noor Mohammadi , Hamid Reza Goudarzi , Saeed Dezianian , Hani Keshavarz Alikhani ,
Volume 13, Issue 3 (5-2019)
Abstract
ABSTRACT
Background and Objectives: Nowadays, infections with antibiotic-resistant bacteria are among the most important causes of mortality worldwide. This has attracted the attention of researchers to seek suitable alternatives for antibiotics. The venom of many toxic species such as arthropods has antibacterial properties. In this study, we investigated antibacterial effects of crude venom of Latrodectus dahli on Escherichia coli, Staphylococcus aureus, and Bacillus subtilis.
Methods: Lyophilized crude venom of L. dahli was dissolved in 50 mM Tris-HCl buffer. Protein concentration was determined by the Bradford assay. Then, the bacteria were exposed to different concentrations (31.25-250 ng/mL) of the crude venom. Inhibitory activity of the venom against the bacteria was determined by MTT assay and determining minimum inhibitory concentration (MIC).
Results: Results of the MTT assay showed that the crude venom significantly inhibited the growth of E. coli (31.25 and 62.5 ng/mL), S. aureus (at 250 ng/mL) and B. subtilis (at 125 and 250 ng/mL). In the MIC experiment, the crude venom significantly inhibited the growth of E. coli (at concentrations of 31.25 and 62.5ng/mL), S. aureus (at concentrations of 31.25-250 ng/mL) and B. subtilis (at concentrations of 31.25-250ng/mL).
Conclusion: The crude venom of L. dahli and its components showed relatively strong antibacterial effects.
Keywords: Spider venoms, Black Widow Spider, Antibacterial agent, Drug-resistance.
Najmeh Jomehpour , Kiarash Ghazvini , Mahshid Jomehpour ,
Volume 13, Issue 3 (5-2019)
Abstract
ABSTRACT
Background and Objectives: Medicinal and aromatic plants are sources of natural antimicrobial compounds that could be useful replacements for antibiotics. The aim of this study was to assess antimicrobial activity of Crocus sativus stigma and Cinnamomum cassia extracts against some Gram-positive and Gram-negative bacteria.
Methods: Antimicrobial activity of methanolic and aqueous extracts of the plants was tested against clinical isolates of Klebsiella pneumonia, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Enterococcus using the microdilution method. Minimal inhibitory concentration (MIC) and minimum bactericidal concentration of each extract against the mentioned bacteria were also determined.
Results: The MIC of the methanolic extract of C. cassia was 80 µg/ml against Enterococcus, K. pneumonia and E. coli. The MIC of the methanolic extract of C. sativus was 160 µg/ml against Enterococcus and S. aureus. The minimum bactericidal concentration of the methanolic extracts of C. sativus and C. cassia was 320 µg/ml against K. pneumonia and 160 µg/ml against Enterococcus.
Conclusion: The extracts of C. sativus and C. cassia exhibit promising antibacterial activities against clinical isolates of the tested bacteria. Our results suggest that the extract of these plants can be further exploited as potential antibacterial agents against multi-drug resistant bacteria.
Keywords: Cinnamomum aromaticum, Crocus, Anti-Bacterial Agents.
Mohammad Habibi Juybari , Hamidreza Pordeli , Saeid Mikaeili ,
Volume 13, Issue 3 (5-2019)
Abstract
ABSTRACT
Background and Objectives: Schiff base ligands are prepared via the condensation reaction of 1, 10- dimethyl–phenantroline aldehyde derivative with some nitrogen donor ligands, such as benzene ring that have different functional groups (-OH, -SH, -OCH3,-CH2OH, -Br) in acetonitrile. Recent studies suggest that Schiff bases might have antibacterial activity. Therefore, we aimed to synthesize new Schiff base complexes and evaluate their antibacterial activity against a number of Gram-positive and Gram-negative bacteria.
Methods: Schiff base ligands and their complexes were characterized by mass spectrometry, infrared spectroscopy and nuclear magnetic resonance spectroscopy. The in vitro antibacterial activity of the Schiff base ligands and metal ions against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was evaluated by determining minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the broth dilution method.
Results: All synthesized Schiff bases exhibited favorable antibacterial activity against the tested microorganism, but the antibacterial effect of compounds 3OH and 3SH was more significant than that of other compounds.
Conclusion: Compound 3EOH has favorable antibacterial activity against the tested bacteria.
Keywords: Schiff bases, antibacterial effect, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa.
Farzaneh Mohammadzadeh Rostami, Saman Shalibeik, Morteza Rabi Nezhad Mousavi,
Volume 14, Issue 1 (1-2020)
Abstract
ABSTRACT
Background and objectives: Nosocomial infections caused by antibiotic resistant bacteria is a life threatening health challenge. This study aimed to determine the frequency of antibiotic resistance genes in clinical isolates from hospitals of Zahedan, southeast of Iran.
Methods: Overall, 818 isolates were collected from different hospital wards. The isolates were identified using conventional microbiological and biochemical tests. Antibiotic susceptibility pattern was assessed by agar disc diffusion method and determination of minimum inhibitory concentration of a number of antibiotics. Multiplex PCR was performed using specific primers for the detection of resistance genes.
Results: The most common species were
Staphylococcus aureus (25%),
Klebsiella pneumoniae (22%) and
Pseudomonas aeruginosa (14%). The rate of methicillin resistance among
S. aureus,
S. epidermidis and
S. saprophyticus was 60%, 43% and 24%, respectively. In addition, 28.5% of enterococci isolates were vancomycin resistant. Among gram-negative bacteria, 45% of
A. baumannii and 24% of
P. aeruginosa were identified as ESBL. A high level of resistance to ampicillin (96%), cefotaxime (89%), gentamicin (89%) and sulfamethoxazole-trimethoprime (60%) was observed in
K. pneumoniae.
Conclusion: Our results highlight the urgent need for an eradication program and a surveillance plan for preventing increased emergence of antibiotic resistant bacteria in the study area.
Keywords: Bacterial Infections, Drug resistance, Zahedan.
Maryam Kouhkan, Miri Mahmoody, Jabbar Khalafy, Sima Pourali, Nasser Samadi,
Volume 14, Issue 2 (3-2020)
Abstract
ABSTRACT
Background and objectives: Antimicrobial resistance is a serious threat to global public health. The overuse and misuse of antibiotics are the most important contributing factors to development of antibiotic resistance. Thus, there is an urgent need to identify and discover new compounds against drug-resistant microorganisms. We have previously synthesized new series of 3-substituted 5H-(1,2,4)triazolo(3',4':2,3) (1,3,4)thiadiazino(5,6-b)quinoxaline derivatives (4a-4f). Here, we evaluate the antimicrobial activity of these derivatives against methicillin-resistant
Staphylococcus aureus, S. aureus, Streptococcus pyogenes,
Pseudomonas aeruginosa,
Escherichia coli,
Candida albicans, Candida tropicalis and
Candida krusei.
Methods: The agar well diffusion and agar dilution methods were used for determining inhibition zone diameter and minimum inhibitory concentration during preliminary evaluation of antimicrobial activity.
Results: All synthesized compounds exhibited antibacterial and antifungal activity against the tested microorganisms
.
Conclusion: Our findings indicate the antimicrobial potential of the six novel synthetic triazolo thiadiazin quinoxaline compounds.
Keywords: Antimicrobial,
Anti-bacterial agents,
Antifungal agents, Triazolo, Thiadiazin, Quinoxaline.
Helena Hanif, Ameneh Elikaei, Hossein Vazini, Ali Mohammadi,
Volume 15, Issue 1 (1-2021)
Abstract
Background and objectives: The spread of infectious diseases and malignant diseases has been increasing in the recent years. The use of chemical drugs, in addition to the development of drug resistance, also cause serious side effects. We conducted the present study to examine the antibacterial, antiviral, and anti-cancer effects of E. camaldulensis as a herbal remedy.
Methods: We extracted E. camaldulensis using a hydroalcoholic solution. The antiviral effect of the plant was investigated at the time of the Herpes simplex virus entry and once the virus entered the cell. Moreover, we evaluated MIC and MBC of E. camaldulensis on Klebsiella pneumonia, Staphylococcus aureus, Streptococcus pyrogens, Streptococcus agalactiae, Acinetobacter baumannii, and Corynebacterium glutamicum. For the evaluation of cell cytotoxicity, HFF-2 (NCBI: C163) and A549 )ATCC: CCL81) cell lines were utilized.
Results: The results of the cytotoxicity test indicated that both cell lines were sensitive to the hydroalcoholic extracts of E. camaldulensis. The MIC for A. baumannii, K. pneumonia, and C. glutamicum was 6.25 µg/ml, and the MIC for S. aureus, S. pyogenes, and S. agalactiae was 12.5 µg/ml. MBC was evaluated as 25 µg/ml for S. aureus, S. pyogenes, and S. Agalactiae. It was 12.5 µg/ml for A. baumannii, K. pneumonia, and S. Agalactiae. IC50 value on entering the virus into the cell was 40 µg/ml, and following the absorption of the virus, the IC50 value was 80 µg/ml.
Conclusion: The results of this study demonstrated that E. camaldulensis is of antibacterial, antiviral, and anti-cancer potentials and could be used as a candidate for the preparation of a new drug.
Nakisa Zarrabi Ahrabi, Ali Souldozi, Yasin Sarveahrabi,
Volume 15, Issue 5 (9-2021)
Abstract
Background and objectives: Antibiotic resistance is a major public health challenge. The pervasive antibiotic misuse can lead to increased antibiotic resistance. Thus, there is a need for discovery of new compounds against drug-resistant microorganisms. We synthesized new series of 1, 3, 4-oxadiazole derivatives (4a-4d) and evaluated the antibacterial and antifungal activity of the derivatives against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, Klebsiella pneumoniae, Aspergillus fumigatus and Aspergillus flavus.
Methods: The new derivatives of 1, 3, 4-oxadiazole were synthesized using a single-stage, high-yield method. The structure of the new compounds was confirmed by infrared spectroscopy, carbon-nuclear magnetic resonance and hydrogen- nuclear magnetic resonance. Then, antibacterial and antifungal activities of the prepared derivatives (1 mg/ml) were evaluated by determining minimum inhibitory concentration and minimum bactericidal/fungicidal concentration using the agar well diffusion method.
Results: All synthesized compounds, especially (4d) with methoxyphenyl group, exhibited powerful antibacterial activity against the tested bacteria. However, the compounds had no antifungal effect.
Conclusion: Our findings indicate the antibacterial potential of the novel synthetic 1, 3, 4-oxadiazole compounds.
Behnoush Khasheii, Pezhman Mahmoodi, Abdolmajid Mohammadzadeh,
Volume 15, Issue 5 (9-2021)
Abstract
Increasing antibiotic resistance is a global health problem. In recent years, due to the indiscriminate use of antibacterial compounds, many bacterial pathogens, including staphylococci, members of the
Enterobacteriaceae family including
Klebsiella pneumoniae and bacteria such as
Pseudomonas aeruginosa and
Acinetobacter baumannii have become multi-drug resistant. Consequently, it is important to explore alternative approaches for eliminating resistant strains. Bacteria synthesize low-weight molecules called siderophores to chelate iron from the environment as a vital element for their growth and survival. One way to deal with resistant bacterial strains is to utilize siderophore-mediated iron uptake pathways as entrance routes for drug delivery. Therefore, the production of drugs with Trojan horse strategy in the form of conjugated siderophore-antibiotic complexes has recently received much attention
for dealing with resistant isolates.
In this review, we discuss the efficacy of siderophore-antibiotic conjugates as a Trojan horse strategy for eliminating drug-resistant pathogens.
Zahra Kiani, Pouria Mohammad Parast Tabas, Khashayar Khalilpour, Mahjoube Goldani Moghadam, Majid Zare_bidaki,
Volume 15, Issue 5 (9-2021)
Abstract
Background and objectives: Medicinal plants have long been considered as one of the most important pillars of traditional medicine. Existing challenges in the treatment of diseases, particularly infectious diseases, are major drivers for herbal medicine studies. Tribulus terrestris has been widely used in traditional medicine to treat various diseases. This study aimed to investigate in vitro antibacterial effect of the aqueous extract of T. terrestris on several oral bacteria.
Methods: In this experimental study, after preparing the aqueous extract of T. terrestris, minimum inhibitory and bactericidal concentrations (MIC and MBC) of the extract were determined against standard strains of Streptococcus mutans, Staphylococcus aureus, Klebsiella pneumoniae and Streptococcus pyogenes using the broth microdilution method. The experiments were repeated three times and the results were analyzed with SPSS 22 using the one-way analysis of variance (ANOVA) and LSD statistical tests with the significance level set at 0.05.
Results: The aqueous extract of T. terrestris had the highest inhibitory effect on S. pyogenes and S. mutans, and the difference between the MIC and MBC values was significant (P <0.05). However, no such effect was observed against S. aureus and K. pneumonia at concentrations below 50 mg/ml when compared to ampicillin and chlorhexidine.
Conclusion: The aqueous extract of T. terrestris has significant antibacterial effects against S. pyogenes and S. mutans. Therefore, it can be incorporated into topical formulations such as toothpaste and mouthwash products after further in vivo and toxicity experiments.
Mobina Hosseini, Meysam Hasannejad-Bibalan, Tofigh Yaghoubi, Mohammadreza Mobayen, Parisa Khoshdoz, Sara Khoshdoz, Niloofar Faraji, Hadi Sedigh Ebrahim-Saraie,
Volume 15, Issue 6 (11-2021)
Abstract
Background and objectives: Bacterial contamination of wounds is a serious problem, particularly in burn patients. Gram-positive bacteria are the predominant cause of infection in newly hospitalized burn cases. This study aimed to survey the prevalence and antibiotic resistance pattern of gram-positive bacterial isolates among burn patients in Rasht, North of Iran.
Methods: This cross-sectional study was conducted on burn patients with a positive culture for gram-positive isolates who were hospitalized in the Velayat Burn Center in Rasht, North of Iran, during 2017-2020. The isolates were identified using standard microbiological methods. Moreover, the antibiotic resistance pattern was determined by the disk diffusion method.
Results: During the study period, 671 bacterial cultures were obtained, of which a total of 16 gram-positive isolates were taken from the patients. The frequency of coagulase-negative staphylococci (CoNS), Staphylococcus aureus, and Enterococcus spp. was 68.7%, 18.8%, and 12.5%, respectively. In addition, the highest rate of resistance in CoNS isolates was against trimethoprim/sulfamethoxazole. The highest rate of resistant among S. aureus isolates was recorded against penicillin. Moreover, Enterococcus faecalis isolates showed a high level of resistance to ampicillin, erythromycin, tetracycline, gentamicin, and ciprofloxacin. All isolates were susceptible to teicoplanin. Moreover, the frequency of methicillin-resistant S. aureus isolates was 66.7%.
Conclusion: Given the increasing prevalence of drug-resistant strains, especially in susceptible burn patients, it is imperative to analyze the bacterial etiology of nosocomial infections periodically and epidemiologically.
Fahimeh Firoozeh, Arezoo Firoozeh, Abbas Salmani,
Volume 17, Issue 3 (5-2023)
Abstract
Background and objectives: Nontuberculous mycobacteria (NTM) are isolated from domestic and animal products as well as man-made systems such as medical devices, drinking water systems, water tanks, and shower streams. This study aimed to investigate the prevalence of NTM in clinical samples in Iran during 2000-2022.
Methods: Published studies addressing the prevalence of NTM in clinical samples in Iran were reviewed according to the Preferred Reporting Items for Meta-Analyses and Systematic Reviews protocol. Original articles in Persian and English published between January 2000 and 2022 in databases such as Scopus, PubMed, Web of Science, Google Scholar, and Iranian databases were included. The prevalence of NTM at 95% confidence interval (CI) was calculated by comprehensive meta-analysis.
Results: Overall, 26 studies were included in the review. The combined prevalence of NTM in positive mycobacterial cultures was 4.5% (95% Cl: 3.1-6.5). Mycobacterium simiae [35.8% (95% CI 16.4-44.4)], Mycobacterium intracellulare [19% (95% CI 8.7-28.3)], and Mycobacterium kansasii [13.4% (95% CI 7.3-24.3)] were the most common slowly growing species, while Mycobacterium fortuitum [24.6% (95% CI 12.9-46.7)], Mycobacterium terrae [18.5 % (95% CI 11.5-29.2)], and Mycobacterium gastri [15.9% (95% CI6.0-41.2)] were the most prevalent rapidly growing mycobacteria.
Conclusion: In summary, our findings indicate a relatively high combined prevalence of NTM in clinical samples in Iran. Some of these species such as M. simiae can have clinical and radiologic manifestations similar to those of TB and are resistant to anti-TB drugs. Therefore, standardizing the use of molecular methods for the detection of NTM seems necessary.
Manasa Sireesha Devara, Sriushaswini Bhamidipati, Vijaya Bharathi Dondapati , Narasinga Rao Bandaru,
Volume 17, Issue 6 (11-2023)
Abstract
Background: Medicinal plants have played crucial roles in the traditional health care system since the origin of mankind. Among them, cinnamon is used not only as a spice in food but also as a substance with many health-beneficial effects. The aim of the present study was to identify the antibacterial activity of cinnamon bark extract against bacterial isolates from patient pus samples that might help treat infections.
Methods: The antibacterial potential of cinnamon bark extract in both ethanol and methanol against 6 bacterial isolates obtained from pus samples received in the Microbiology Laboratory was identified by agar well diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) using standard techniques.
Results: By agar well diffusion, the highest inhibitory activity of ethanol and methanol extracts of cinnamon was shown by Staphylococcus aureus, followed by coagulase-negative Staphylococci. The lowest inhibitory effect was shown by Proteus mirabilis. The ethanol extract of cinnamon MIC and MBC ranged from 6.25 mg/mL to 12.5 mg/mL and 12.5 mg/mL to 50 mg/mL. The methanol extract of cinnamon MIC showed a value of 12.5 mg/mL, and the methanol extract of MBC ranged from 12.5 mg/mL to 50 mg/mL against all bacterial isolates of the present study.
Conclusion: Staphylococcus aureus is sensitive to the alcoholic extract of cinnamon bark, but its effect is less than that of the selected antibiotic.
Bhawana Bajare, Akanksha Dhangar, Supriya Tankhiwale, Sunanda Shrikhande,
Volume 18, Issue 2 (3-2024)
Abstract
Background: Pyogenic infection is a significant cause of morbidity. Infection with multidrug-resistant strains poses a major difficulty in the treatment. The study was conducted to know the bacteriological profile of pyogenic infections and their antibiotic susceptibility.
Methods: A cross-sectional study was conducted in a tertiary care hospital from October 2021 to March 2022. Isolates from pus specimens were subjected to an antibiotic sensitivity test using the Kirby-Bauer method as per CLSI 2021.
Results: Out of 752 samples, etiology could be revealed in 510 (68.4%) specimens. Enterobacterales dominated the profile, with K pneumoniae isolated in the maximum number of specimens. Staphylococcus aureus was the culprit in 14% of the cases. Non-fermenters were isolated in 17% of the cases. Methicillin resistance in S aureus was 67%. Gram-positive cocci showed high sensitivity to linezolid. For both Piptaz and carbapenem, Enterobacterales and non-fermenters showed around 50% and 60% susceptibility, respectively.
Conclusion: Continuous surveillance of the aetiologic agents of pyogenic infections and their antibiotic sensitivity pattern needs to be done to design and implement the antibiotic policy for the infection in our set-up.
Zahra Ahmadnia , Samane Rouhi, Hamed Mehdinezhad , Siamak Sabaghi , Alireza Firouzjahi , Mohammad Ranaei , Hossein Ghorbani , Maryam Pourtaghi, Mana Baziboron ,
Volume 18, Issue 4 (7-2024)
Abstract
Pasteurella species are one of the most common pathogenic bacteria in domestic animals, and they are seen more in people with weak immune systems. This research aims to investigate a case of a patient with multiple sclerosis from whose sputum Pasteurella multocida (P. multocida) was isolated. The patient was a 28-year-old man with multiple sclerosis who had persistent coughs due to food being stuck in his throat. The patient was a 28-year-old man with multiple sclerosis who had persistent coughs due to food being stuck in his throat. The primary diagnosis was pneumonia hydropneumothorax and complete collapse of the left lung. The patient's sputum culture after the first visit to the hospital was positive for P. multocida, which was not found in a second culture. In the subsequent cultures of the patient, Acinetobacter, Klebsiella, Pseudomonas aeruginosa (P. aeruginosa), and Citrobacter were found, which had extensive drug resistance to all antibiotics. In the secondary computerized tomography (CT) scan, mild pleural effusion on the left side, pneumothorax, and complete collapse with bronchiectasis was seen. Despite the treatments, the patient finally died of cardiac arrest and bradycardia. Infection with P. multocida was found in a patient with multiple sclerosis. Also, hospital-acquired infections with drug resistance caused by the weakness of the patient's system appeared in the patient who was hospitalized in the intensive care unit (ICU), and finally, the patient died. According to antibiotic patterns, the best antibiotic to which the bacteria is sensitive can be considered the primary treatment to avoid irrational antibiotic prescriptions.
Maryam Rezaeian, Laleh Hoveida,
Volume 19, Issue 1 (1-2025)
Abstract
Background: Infections caused by bacteria transmitted from food, including carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa (P. aeruginosa), and Acinetobacter baumannii (A. baumannii), are spreading, and this has caused concerns in treatment. This study investigated the frequency of carbapenem resistance genes in Enterobacteriaceae, P. aeruginosa, and A. baumannii, isolated from raw chicken meat.
Methods: In this cross-sectional study, 100 samples of raw chicken meat were collected from Isfahan. Bacterial contamination was evaluated and confirmed using biomedical tests. Antibiotic sensitivity tests were performed using disc diffusion for Enterobacteriaceae, P. aeruginosa, and Acinetobacter baumannii isolates. The frequency of carbapenem resistance genes (OXA-181, OXA-48, VIM, NDM, IMP, and KPC) was determined through polymerase chain reaction (PCR) analysis.
Results: Out of 100 samples, 70 were positive for bacterial infection, of which 30 were infected with Escherichia coli (E. coli), 14 samples with Klebsiella pneumoniae (K. pneumoniae), 9 samples with Salmonella typhimurium (S. typhimurium), 11 samples with P. aeruginosa, and 6 samples with A. baumannii. The highest levels of antibiotic resistance were estimated to be tetracycline, cotrimoxazole, gentamicin, trimethoprim, and streptomycin, and the lowest levels were azithromycin and rifampin. Among genes encoding resistance to carbapenem, NDM and OXA-48 genes were the most commonly expressed, with a frequency of 60% and 28.24%, respectively.
Conclusion: This study found significant bacterial contamination, especially for Enterobacteriaceae, with notable antibiotic resistance to tetracycline. Carbapenem resistance genes NDM and OXA-48 were prevalent, indicating the urgency of addressing antibiotic resistance.
Mojtaba Raeisi , Fatemeh Hooshmand , Marziyeh Gheraati, Masood Aman Mohammadi , Negin Mehdinejad ,
Volume 19, Issue 4 (7-2025)
Abstract
Background: Due to the growing problem of antibiotic-resistant bacteria and rising consumer preference for natural food preservatives, there is an increased interest in plant-based antimicrobial agents. While Salix aegyptiaca (S. aegyptiaca), also known as Musk Willow, is a promising source of bioactive compounds, its antibacterial properties have not been extensively studied. Therefore, this research investigates the chemical composition and antibacterial effectiveness of essential oils extracted from the leaves and male inflorescences of S. aegyptiaca against important foodborne pathogens like Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Listeria monocytogenes (L. monocytogenes), and Salmonella enteritidis (S. enteritidis).
Methods: Essential oils were extracted from the leaves and male inflorescences of S. aegyptiaca through hydrodistillation. The chemical composition of these oils was then determined by gas chromatography-mass spectrometry (GC-MS) to identify their bioactive constituents. The antibacterial efficacy of the extracted oils was assessed using several methods, including the determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), as well as diffusion assays (Agar disk and agar well diffusion).
Results: GC-MS analysis revealed that the leaf oil was predominantly composed of 1,4-dimethoxybenzene, citronellol, and eugenol, whereas carvone was the main constituent of the male inflorescence oil. The leaf oil demonstrated superior antimicrobial activity, particularly against S. aureus, for which the MIC was determined to be 1250 µg/mL. Both oils indicated limited efficacy against Gram-negative bacteria. Of the strains tested, S. aureus proved to be the most susceptible, while E. coli exhibited the highest resistance.
Conclusion: The essential oils extracted from S. aegyptiaca, especially from its leaves, have shown significant antibacterial effects against common foodborne pathogens. This suggests they could be used as natural food preservatives, offering a viable alternative to synthetic additives. Additional research is necessary to investigate their use in food products and to establish their toxicological safety.
Naila Begum , Amit Garg , Karvi Agarwal ,
Volume 19, Issue 5 (9-2025)
Abstract
Background: Colistin is regarded as the last resort for managing infections caused by multidrug-resistant (MDR) Gram-negative bacilli (GNB). The World Health Organization (WHO) includes colistin on its list of critically necessary antimicrobials. Minimum inhibitory concentrations (MICs) are used to monitor the development of colistin resistance. This study aimed to assess the performance of the Broth Microdilution Method (BMD) against routine Kirby-Bauer disk diffusion (KBDD) and automated BD Phoenix for the detection of the in vitro activity of colistin against GNB.
Methods: A cross-sectional study was conducted in the Department of Microbiology, LLRM Medical College, Meerut, Uttar Pradesh, from September 2023 to January 2024. The KBDD method, BMD method, and BD Phoenix (Becton Dickinson, USA) automated system were used to detect colistin susceptibility in 320 GNB isolated from various clinical samples. MIC determined by the BMD method was interpreted according to Clinical Laboratory Standards Institute (CLSI) 2023 guidelines.
Results: In our study, 320 isolates of GNB were identified from patients with a mean age of 45.34 years. A total of 320 isolates [145 (45.31%) Escherichia coli, 124 (38.75%) Klebsiella pneumoniae, 32 (10.0%) Pseudomonas aeruginosa, and 19 (5.93%) Acinetobacter baumannii complex] were tested simultaneously with all three methods for colistin susceptibility. The overall resistance to colistin among GNB was found to be 17.18% by the gold standard BMD method, 15.31% by BD Phoenix, and 14.37% by KBDD.
Conclusion: BMD is the most cost-effective, authentic method for routine testing of colistin susceptibility as compared to other methods. The comparative analysis revealed that BMD is superior to other methods in detecting colistin susceptibility, emphasizing its potential role in guiding clinicians in antibiotic therapy decisions.
Shahnaz Halimi , Pegah Shakib , Elham Mehrabnejad , Faranak Rezaei , Somayeh Delfani ,
Volume 19, Issue 6 (11-2025)
Abstract
Background: The widespread increase in the prevalence of antibiotic resistance in bacteria is considered one of the biggest problems in the global health and treatment system today. Therefore, this study was conducted to investigate the prevalence and antibiotic resistance pattern of bacteria isolated from blood cultures at Shahid Rahimi Hospital in Khorramabad in 2018.
Methods: This cross-sectional study investigated blood cultures of patients admitted to Shahid Rahimi Hospital from June to December 2018. The disc diffusion method was used according to CLSI instructions, and the data were analyzed using SPSS software.
Results: Out of a total of 2591 blood culture samples, 247 blood culture samples were positive. The highest frequency was related to the emergency department (62%) and ICU (23%), and the lowest frequency was related to the children's department (2.4%). Among the tested samples, 28% were Gram-negative bacilli and 72% were Gram-positive cocci. The most common Gram-negative and Gram-positive bacteria were Escherichia coli (38%) and Staphylococcus epidermidis (54.2%), respectively. Among Gram-negative bacteria, the highest level of resistance was seen in Acinetobacter baumannii strains, which showed resistance to all antibiotics. Among Gram-positive bacteria, the highest resistance of Streptococcus group D strains to the antibiotic erythromycin (92%) was reported.
Conclusion: The prevalence of antibiotic resistance in common microorganisms isolated from blood cultures in different departments is worrying, and choosing an effective drug to eliminate these bacteria by performing accurate laboratory tests is of particular importance.
Maanasa Bhaskar Manalikandy, Ankita Mohanty , Noyal Maria Joseph , Raja Jaisundar Selvaraj, Sujatha Sistla ,
Volume 19, Issue 6 (11-2025)
Abstract
Background: Mycobacterium abscessus is a rapidly growing non-tuberculous mycobacterium that can cause various infections in humans. The identification of nontuberculous mycobacteria remains a challenge to date due to the availability of limited resources. There have been reports of device-related infections caused by these bacteria. Improper care of cardiac implants can give rise to infections that need to be identified promptly. This report emphasizes the need for early and prompt diagnosis of non-tuberculous mycobacterial infections.
Case Report: Here, we present a case of a 69-year-old man who presented with an atrioventricular block and therefore underwent pacemaker implantation. The implant became infected with Mycobacterium abscessus, which resolved after appropriate treatment and pacemaker removal.
Conclusion: Non-tuberculous mycobacteria must be promptly identified and treated for the appropriate duration to prevent complications associated with them.
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