فهرست مطالب

Jundishapur Journal of Microbiology - Volume:15 Issue: 3, Mar 2022
  • Volume:15 Issue: 3, Mar 2022
  • تاریخ انتشار: 1401/03/10
  • تعداد عناوین: 6
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  • Hassan Ghali Abdulhasan Alshami, Maryam Abbasi Shaye, Masoumeh Bahreini, Mohammad Reza Sharifmoghadam* Page 1
    Background

    Carbapenem-resistant Acinetobacter baumannii strains are one of the most severe factors in hospital infection worldwide, in which the beta-lactamase enzyme is one of the main resistance mechanisms.

    Objectives

    This study aimed to evaluate the presence of carbapenem-resistant beta-lactamase genes and determine antibiotic resistance patterns in the clinical isolates of A. baumannii from patients hospitalized in the Shahid Kamyab Hospital, Mashhad, Iran.

    Methods

    Out of 286 collected isolates from patients hospitalized in Shahid Kamyab Hospital (from March 2017 to June 2017), 31 isolates were confirmed to be A. baumannii using biochemical tests. Antibiotic susceptibility testing was conducted using the disc diffusion method according to the CLSI standard protocols. The presence of beta-lactamase genes, namely blaVEB, blaPER, blaAmpC, blaVIM, blaIMP, blaSHV , and blaTEM, was detected using polymerase chain reaction.

    Results

    In this study, 31 isolates were identified as A. baumannii, all of which revealed high resistance to ceftazidime, cefixime, ceftriaxone, meropenem, imipenem, cefotaxime and cephalexin. In this case, the lowest resistance (19.35%) was observed against polymixin B. Moreover, blaAmpC, blaTEM, blaSHV , blaPER, and blaVIM were observed in 93.54% (29), 51.61% (16), 48.38% (15), 41.93% (13), and 77% (24) of the isolates, respectively. However, blaVEB and blaIMP were observed in none of the isolates.

    Conclusions

    The results showed high carbapenem resistance and high frequency of beta-lactamase resistance genes among the clinical isolates of A. baumannii.

    Keywords: Acinetobacter baumannii, Antibiotic Resistance, Carbapenem, Beta-Lactamase
  • Elvis Agbo, Zichen Ye, Zijun Tang, Yangming Chen, Ting Wang, Qiang Fu* Page 2
    Background

    Staphylococcus aureus is one of the most virulent pathogens inducing various diseases in humans and animals. Disturbingly, the degree and rate of drug resistance in this pathogen have sharply increased and have become a global concern.

    Objectives

    This study analyzed the lytic activity and the biological characteristics of a mitomycin C-induced bacteriophage from S. aureus isolated and identified from hospital sewage to explore novel antibacterial therapeutic strategies for the clinical treatment of drug-resistant S. aureus, including urinary tract infections caused by MRSA strains.

    Methods

    The new bacteriophage vB_SauP_P992, which can effectively lyse the MRSA strain, was successfully isolated and purified using the double agar plate method. In this regard, pH sensitivity, one-step growth curve, the optimal multiplicity of infection (MOI), thermo-sensitivity, phage host range, and the effects of organic reagents on phage activity were determined.

    Results

    Electron microscopic results showed that the bacteriophage head was hexagonal with a non-contractile tail and could form a single, neatly-bordered plaque. Moreover, the optimal MOI was 0.1. The one-step growth curve showed a bacteriophage incubation period of about 20 min, a lysis period of 90 min, and a burst size of about 65.8 PFU per infected cell. The bacteriophage vB_SauP_- P992 had acceptable thermal stability, pH stability, and resistance to physical and chemical factors, indicating a bacteriophage with no capsule.

    Conclusions

    With an intense lytic activity and acceptable stability, this novel bacteriophage lays a solid foundation to enrich the bacteriophage library and better prevent and control drug-resistant S. aureus infections.

    Keywords: Staphylococcus aureus, Bacteriophage, Isolation, Biological Characteristics
  • Nahid Hosseinzadeh-sohi, Shahin Najar-Peerayeh, Bita Bakhshi* Page 3
    Background

    Gastrointestinal colonization with resistant pathogens is significant because they could be easily transmitted to other hosts or spread to different microbiota through mobile genetic elements.

    Objectives

    This study assessed the prevalence of fecal carriage of extended-spectrum β-lactamase-producing and carbapenemaseproducing Enterobacteriaceae (ESBL-E and CPE, respectively) among hemodialysis patients and the factors affecting its occurrence in a hospital in Tehran.

    Methods

    From January 2018 to May 2019, 150 hemodialysis patients referred to a hospital in Tehran were sampled in this study. Stool samples of the patients were diluted in saline and cultured on MacConkey agar plates containing cefotaxime, ceftazidime, imipenem, and meropenem discs. The clinical data were analyzed to identify the risk factors using a logistic regression model.

    Results

    The colonization rate of ESBL-E was 48.6%, while only 2% of patients were identified as the carriers of CPE (3 of 150). A higher prevalence rate was obtained for intestinal carriage of ESBL-E among hemodialysis patients aged 18 to 42 years using multivariate analysis. The prevalence rate of multidrug-resistant isolates was 73.8%. The blaCTX-M1 gene was identified as the most prevalent ESBL gene. Among carbapenemase-encoding genes, blaKPC and blaoxa-48 were found in 12 and two isolates, respectively.

    Conclusions

    These results demonstrated a high prevalence rate of ESBLs among hemodialysis patients, although this rate was low for carbapenemases. Therefore, more control measures should be taken in hospitals to prevent the spread of antibiotic resistance genes in healthcare settings.

    Keywords: Antimicrobial Resistance, Carbapenemase-producing Enterobacteriaceae, Enterobacteriaceae, Extended-spectrumβ-lactamase, Hemodialysis Patients
  • Sunarno Sunarno *, Yudi Hartoyo, Novi Amalia, Sundari Nur Sofiah, Aulia Rizki, NellyPuspandariDwi Febriyana, Tati Febrianti, Ratih Dian Saraswati, Fauzul Muna, RisqaNovita, Lisa Andriani Lienggonegoro, Fitrah Ernawati Page 4

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    Background

    Corynebacterium diphtheriae, C. ulcerans, andC. pseudotuberculosis are known as diphtheria-causing bacteria. Although diphtheria therapy is administered based on the clinical manifestations, some cases are mild and atypical. The immediate and accurate identification of diphtheria-causing bacteria is of paramount importance to prevent the spread of the disease and provide case management as early as possible. Unfortunately, conventional methods as the gold standard are time-consuming.

    Objectives

    This study aimed to develop and implement a multiplex real-time PCR with the dtxR and tox genes as the target to identify three species of diphtheria-causing bacteria and screen their toxigenicity quickly and accurately.

    Methods

    The research sample encompassed seven reference strains, one synthetic DNA, 30 archived isolates, and 924 clinical specimens isolated from 311 diphtheria cases and 613 close contacts. The conventional methods as the gold standard and the established PCR assay were used to verify the results of multiplex real-time PCR developed in this study.

    Results

    Themultiplex real-time PCR could identify seven reference strains, one synthetic DNA, and 30 archived isolates as accurately as the conventional methods and the established PCR. Similar to established PCR, the multiplex real-time PCR identified diphtheriacausing bacteria in 120 (38.6%) out of 311 and 12 (2%) out of 613 clinical specimens from diphtheria cases and close contacts, respectively. Meanwhile, the conventional methods identified diphtheria-causing bacteria in 79 (25.4%) out of 311 and three (0.5%) out of 613 clinical specimens.

    Conclusions

    The multiplex real-time PCR developed in this study can be used to identify three species of diphtheria-causing bacteria and screen their toxigenicity quickly and accurately. However, in this study, no diphtheria-causing bacteria other than C. diphtheriae was found in the clinical samples using the PCR or conventional methods. PCR is more sensitive than the conventional methods and can be used as an additional test in diphtheria laboratories.

    Keywords: Diphtheria, Corynebacterium diphtheria, C. ulcerans, C. pseudotuberculosis, Polymerase Chain Reaction
  • Fitriana Fitriana *, Febri Setyo Nugroho, Maria Holly Herawati Page 5
  • Ahmad Hormati, Mohammad Khalifeh Gholi, Alireza Sharifi, Mahdiieh Ghoddoosi, Mehdi Pezeshgi Modarres, Pooya Jafari, Mahdi Zarei, Mojde Bagheri, Mohaddeseh Zojaji* Page 6
    Background

    Helicobacter pylori (H. pylori) is one of the most common human bacterial infections, accounting for the infection of half of the world’s population. The polymerase chain reaction (PCR) has high specificity and sensitivity in diagnosing this bacterial infection.

    Objectives

    The present study aimed to compare the sensitivity and specificity of the fliD gene and the most widely used glmM gene in the PCR technique.

    Methods

    The research population encompassed patients with indications for upper endoscopy. This cross-sectional study compared the sensitivity and specificity of a proposed gene (fliD) with the most widely used glmM gene to detect the H. pylori infection in tissue samples.

    Results

    The participants encompassed ninety-nine participants aged above 18 years. Their median age was 45.92 ± 13.63 years. The most common complaints of the patients were epigastric pain and heartburn. Our described gold standard detected 61.6% and 38.4% as positive and negative, respectively. The sensitivity and specificity were 72.1% and 100.0% for the routine PCR (glmM gene) and 80.3% and 94.7% for the proposed PCR (fliD gene).

    Conclusions

    Different genes have been used to detect H. pylori in PCR. The glmM gene is easily used to diagnose the H. pylori infection; however, according to the present findings, the fliD gene has higher sensitivity than the glmM gene. Accordingly, the former can be used as a screening gene for the H. pylori infection in the PCR technique.

    Keywords: Helicobacter pylori, Polymerase Chain Reaction, fliD, glmM, ureC, Sensitivity, Specificity