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Showing 66 results for Bacteria
Isolation of Pasteurella multocida and pan-drug-resistant bacteria causing nosocomial infection in a patient with multiple sclerosis: A Case Report and Literature Review
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.
 

Prevalence of carbapenem resistance genes in Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii from meat samples
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.
 

Comparative analysis of antibacterial activity and chemical composition of essential oils from Salix aegyptiaca male inflorescences and leaves
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.
 

Antimicrobial susceptibility testing of colistin: Evaluation of standard broth microdilution method for gram-negative bacilli
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.


Investigation of the frequency and antimicrobial susceptibility patterns of bacteria isolated from blood cultures in Khorramabad in 2018
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.
 

Pacemaker pocket infection due to Mycobacterium abscessus subspecies abscessus: A Case Report and Literature Review
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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