Journal of Medical Bacteriology (JMB), as the official publication of the Iranian Society for Medical Bacteriology, is quarterly published by Tehran University of Medical Sciences (TUMS). This peer-reviewed scientific journal is devoted to publishing high-quality researches and novelties regarding various aspects of human and animal pathogenic bacteria as the main aim of the journal. JMB features reports of original research including Antimicrobial Agents and Chemotherapy, Bacterial Poisoning and Toxins, Epidemiology, laboratory and Diagnostics, Pathogenicity, Vaccines and Virulence, Pathogen-Host Interactions, and Typing and Identification. JMB will also consider Minireviews, Original Articles, Short Communications, Methodology and Protocols, Conference Reports, and Editorials. 

Current Issue

Vol 10 No 3-4 (2021)

Original Articles

  • XML | PDF | downloads: 65 | views: 98 | pages: 1-10
    Background:     Nanoparticles are a new generation of antimicrobials. Zinc oxide nanoparticles have attracted a great deal of interest in their medical applications. The aim of the present study was to investigate the effect of zinc nanoparticles on the expression of mrkA and fimA genes in drug-resistant K. pneumoniae. Methods:     A total of 30 clinical isolates of K. pneumoniae were collected from Sina hospital and all the isolates were identified by biochemical tests. Antimicrobial resistance pattern was determined by disk diffusion method. PCR method was used to investigate the presence of mrkA and fimA genes. Biofilm phenotypic test was performed and after conducting MIC test by micro dilution method, real-time PCR was used to study the effect of zinc oxide nanoparticle on the expression of fimA and mrkA genes. Results:     The highest resistance rate was against cefotaxime and ceftazidime antibiotics (67%). Twenty seven isolates harbored fimA gene while 24 isolates harbored mrkA gene. Five isolates were identified as strong biofilm producers. MIC values for zinc oxide was 2500 µg/ml in all five isolates. Results of real-time PCR showed that the expression levels of mrkA and fimA genes in isolates treated with zinc oxide decreased 8.5 and 9 fold, respectively, compared with the control. Conclusion:     This study suggests that zinc oxide can be a suitable candidate for the inhibition of the two studied virulence genes in K. pneumoniae.
  • XML | PDF | downloads: 46 | views: 86 | pages: 11-18
    Background: Pseudomonas aeruginosa is a leading cause of hospital-acquired infections that causes severe diseases in immuno-compromised individuals. integrons have a major role in multidrug resistanct, diversity, evolution and recombination strains. Various animals may act as the reservoir for bacterial humans pathogens. This study is aimed to evaluate the frequency of class 1, 2 and 3 integrons in P. aeruginosa isolates detected in raw milks.Methods: Identification of isolates were confirmed with morphology, Gram staining and biochemical tests. Drug resistance to various antibiotics was investigated using agar disk diffusion method. After DNA extraction of the isolates, they were subjected to a polymerase chain reaction for detection of class 1, 2 and 3 integrons.Results: In this study, 60 P. aeruginosa isolates were isolated from raw milk samples. The isolates showed resistance to amikacin (100%), ampicillin (100%), gentamicin (86.6%), cefotaxime (10%), ciprofloxacin (6.6%) and ceftazidime (3.3%). PCR analysis revealed the presence of intI-1in 49(81.6%), intI-2 in 9(15%), and intI-3 in 31(51.6%) isolates. Furthermore, class 1 and class 2 integrons were detected in 8(13.3%). In place, class 1 and class 3 integrons were observed in 26(43.3%) and class 2 and class 3 integrons in 6(10%) isolates.Conclusion: Ciprofloxacin and ceftazidime were the most effective antibiotics against P. aeruginosai isolates in this study. The distribution of different classes of integrons in this study was high and it sheds light on the importance of regulations on the antibiotic uses.  
  • XML | PDF | downloads: 30 | views: 51 | pages: 19-27
    Background: Staphylococcus saprophyticus is one of the most common causes of urinary tract infections (UTIs). Antibiotic resistance against imipenem is increasing worldwide. Our study aimed to investigate the effect of imipenem on expression of the S. saprophyticus serine-aspartate repeat protein-encoding genes by isolating multidrug-resistant strains. Methods: In this descriptive study, 500 specimens were randomly collected from clinical specimens. Firstly, isolates were identified using standard tests. Then, s. saprophyticus species harboring sdrC, D and E genes were detected using multiplex PCR. Antibiotic susceptibility testing and MIC values of imipenem performed and target genes expression detected by Real time PCR. Results: Out of 500 samples, 387 Staphylococcus species were isolated, among which 155 strains were S. saprophyticus species. PCR data indicated that 36.77% of S. saprophyticus isolates harbored one of sdr family genes. The MIC and subMIC values obtained for S. saprophyticus species treated with imipenem were 125 μg/ml and 225 µg/ml, respectively. Treatment with imipenem induced significant decrease in the expression of sdrC and sdrD genes as fold changes were -1.241 and -1.322, respectively. There was no statistically significant in sdrE gene expression. Conclusion: The results of our study showed that resistance to imipenem was significantly higher in strains harboring sdrE gene. Also, treatment with imipenem did not cause any significant change in the expression of sdrE gene, which could be a factor in the application of antibiotic resistance by bacteria to this antibiotic. In addition, the present study raises another alarm about the increased risk of antibiotic resistance
  • XML | PDF | downloads: 20 | views: 41 | pages: 28-32
    Background:     Clostridium tetani is the etiologic agent of tetanus which is a hyper acute disease affecting various animal species. Tetanus distributes worldwide However its occurrence highly depends on the vaccination programs and the level of hygiene in a flock. There are a lot of flocks in Iran which have not been received vaccine. The aim of the present study is to illustrate the importance of tetanus as a cause of high mortality in small ruminants. Methods:     In a flock consisting 600 sheep, all the animal’s ears were tagged. A total of 50 animals showed clinical signs of tetanus. The wound exudates were collected from deep parts of the injured ears. The samples were stained by gram staining and were cultured on blood agar media. Then biochemical tests were conducted on the suspected colonies. Results:     The animal’s symptoms included limb stiffness, spasticity, trismus, sternal recumbency, lateral recumbency and opisthotonus were observed. The laboratory results confirmed the presence of Clostridium tetani. Conclusion:     According to the present study, consideration should be given to the tetanus vaccination which is crucial in high susceptible species and flocks managed base on traditional methods. Using ear tags in a clean and hygienic manner and spraying antibiotics on the wounds during the process may also decrease the probability of tetanus.
  • XML | PDF | downloads: 31 | views: 37 | pages: 33-38
    Background:     Coxiella burnetii the causative agent of Q fever and one of the most important abortifacient agents in goats, is a gram negative bacteria. During an outbreak of coxiellosis, the infected animals shed Coxiella burnetii through vaginal discharges, feces, milk and the urine. The present study focused on the presence of Coxiella in the parturition discharges of goats with full-term delivery. Methods:     A total of 25 goats in their first parturition and 25 other goats in their second parturition with no clinical signs of infection caused by Coxiella burnetti, were randomly selected and examined. The vaginal swab samples which had been collected from the animals were extracted and tested by PCR. Results:     In the 25 goats that had parturated for the first time, 19 positive samples were detected (76%). Eighteen samples that had been collected from other goats in their second parturition ,had C.burrenti DNA in their vaginally swabs (72%). The infection rate in goats that had partuated for the first time ,was higher than the goats in their second parturition, had though the difference was not significant. Conclusion:     According to the high prevalence of Coxiella burrentii,the risk of abortion in goats and also as coxiellosis is a zoonotic disease, it is necessary to pay more attention to the bacterium and to conduct appropriate strategies for prevention of disease.
  • XML | PDF | downloads: 10 | views: 25 | pages: 39-50
    Background:       The biometric fingerprinting clocking devices are now commonly being used in Nigeria to record human biodata. This system involves physical contact between the skin and surface of the device, which is likely to be contaminated by microorganisms of multiple users. This study aimed to investigate the role of biometric fingerprinting clocking devices as a potential source for microbial contaminants spreading. Methods:       This study was conducted from February to May 2018 and involved samples collected from the surfaces of the biometric fingerprinting device using sterile swabs. Samples were inoculated on MacConkey, Blood, Nutrient, and Sabouraud dextrose agar media and incubated aerobically at 37oC for 24 hours. Colonies from the agar media were characterized biochemically to identify microbial species and their antibiotic susceptibility test was determined by the Kirby Bauer disc diffusion method. Results:       Totally, 221 samples (92%) containing microbial organisms grew. Bacteria isolated included: Staphylococcus aureus (29.6%), Escherichia coli (19.4%), Bacillus species (17.43%), Klebsiella species (10.2%), Streptococcus species (8.55%), Pseudomonas spp (7.24%), Proteus spp (2%) and Enterococcus spp (0.66%). The majority of the bacteria were resistant to at least two antibiotics used. The fungi isolated were Trichophyton mentagrophytes (25%), Trichophyton rubrum (20%), Epidermophyton species (19%), Mucor species (17%), Aspergillus species (11%), and Microsporum species (5%) to decrease occurrence. Conclusion:       Hand disinfection with a proper cleaning regimen is recommended to reduce contamination on the biometric fingerprinting clocking devices.

Review Articles

  • XML | PDF | downloads: 33 | views: 49 | pages: 51-65
    Background:      Because of the current limitations of therapeutic methods, the worldwide appearance and spreading of carbapenem-resistant (CR)-Klebsiella pneumoniae has made to a key concern in the healthcare system. K. pneumoniae, the most frequent Klebsiella species is the cause of human infections, classified as top three pathogens of global concern which established in 2014 WHO Global Report on Surveillance of Antimicrobial Resistance. Methods:      Embase, PubMed/Medline, Scopus, Google Scholar, Web of Sciences and Iranian databases were searched to retrieve the potentially relevant studies. In this review, we explored the prevalence of K. pneumoniae generating three universal carbapenemases (KPCs, NDMs, and OXA-48-like) by following keywords: "carbapenem resistance" and"blaKPC" and"metallo beta lactamase" and "blaNDM" and "blaOXA" and "Klebsiella pneumoniae" and Iran. Results:      After exploiting predefined inclusion and exclusion criteria, 37 articles were collected that reported prevalence of carbapenem-resistant Klebsiella pneumoniae. At finally, 20 studies reported blaNDM , 17 studies reported blaKPC, 14 studies reported blaOXA-48 and blaVIM as gene cause resistance among Klebsiella pneumoniae strains. The described resistance to carbapenem varied across different studies, ranging from 4.4% to 100%. Conclusion:      Our findings demonstrated that the high prevalence of carbapenem-resistant Klebsiella pneumoniae expresses concern over most Iranian hospitals.
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