The "Iranian Journal of Microbiology (IJM) "is the offi­cial scientific quarterly publication of the Iranian Society of Microbiology which is published by Tehran University of Medical Sciences.  The areas that are covered by IJM are medical, veterinary, food and water, applied and  environmental microbiology. It ac­cepts Original Papers, Review Articles, Short Communications and Let­ters to the Editor in the fields of Microbiology.

Current Issue

Vol 13 No 2 (2021)
Published: 2021-04-10

Original Article(s)

  • XML | PDF | downloads: 23 | views: 21 | pages: 145-155

    Background and Objectives: In first May 2020, Indonesia has been successfully submitted the first three full-length sequence of SARS-CoV-2 to GISAID database. Until September 10th, 2020, Indonesia had submitted 54 WGS. In this study, we have analyzed and annotated SARS-CoV-2 mutations in spike protein and main proteases.
    Materials and Methods: The Whole Genome Sequence (WGS) of Indonesia were obtained from GISAID data base. The 54 data were taken from March to September 10th, 2020. The sequences corresponded to Spike Protein (SP), 3-chymotrypsin like protease (3CLpro), and papain like protease (PLpro) were selected. The Wuhan genome was used as reference.
    Results: In total WGS from Indonesia, we found 5 major clades, which dominated as G clade, where the mutation of D614G was found. This D614G was identified as much as 59%, which mostly reported in late samples submitted. Beside D614G mutation, we report three unique mutations: A352S, S477I, and Q677H. Besides, some mutations were also detected in two domains that were expected to be conserved region, the main viral proteases: PLpro (P77L and V205I), 3CLpro (M49I and L50F).
    Conclusion: The analysis of SARS-CoV-2 from WGS Indonesia showed a high genetic variation. The diversity in SARS-CoV-2 may epidemiologically enhance virulence and transmission of this virus. The prevalence of D614G over the time in different locations, indicating that changes in this mutation may related to host infection and the viral transmission. However, some mutations that have been reported in this study were not eligible for the most stable conformation.

  • XML | PDF | downloads: 19 | views: 25 | pages: 156-160

    Background and Objectives: Escherichia coli is a Gram-negative organism causing mild to severe infections, with a wide spectrum range of organs involved. The study aimed to describe antibiotics susceptibility of E. coli from clinical specimens from October 11, 2019 to September 11, 2020.
    Materials and Methods: Study was conducted retrospectively in a private microbiology laboratory in Mataram Indonesia. Period of study divided as two groups after WHO declared COVID-19 as pandemic by March 11, 2020; group A including the specimen related to September 2019 to March 11th 2020 and group B including the specimens related to March 11th 2020 to September 2020. All clinical specimens were subjected to identify E. coli isolates and their antibiotics susceptibility using WHO-NET 5.6 version.
    Results: Totally, 148 E. coli isolates were found in group A and 62 isolates in group B. Prevalence of extended-spectrum beta lactamase (ESBL)- producing E. coli in group A was 50% and in group B was 20.9% with significantly difference (p<0.05). There was an increase in susceptibility to 10/16 antibiotics; where 3 antibiotics ofloxacin, aztreonam, and fosfomycin were significant (p<0.05). There was a significant decrease in susceptibility to the antibiotics piperacillin (p=0.012), amoxicillin (p=0.002), cefadroxil (p=0.036) and ampicillin (p=0.036). Type of infections between two groups: musculoskeletal infections, pneumonia, urinary tract infections and sepsis were not significant.
    Conclusion: Reduced number of E. coli isolates between two groups with decrease of ESBL-producing E. coli contribute in dynamics of antibiotics susceptibility. The longer period of analysis is needed to be done, due to the ongoing COVID-19 pandemic.

  • XML | PDF | downloads: 6 | views: 11 | pages: 161-170

    Background and Objectives: Increasing the rate of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has given rise to a major healthcare issue in clinical settings over the past few years. Treatment of these strains is hardly effective since the plasmid encoding ESBL may also carry other resistance genes including aminoglycosides. The current study aimed to evaluate the prevalence of ESBL-producing K. pneumoniae and investigate the coexistence of Cefoxitamase-Munich (blaCTX‑M) with aminoglycoside-modifying enzyme (AME) genes, aac(3)IIa as well as aac(6′)Ib, in CTX-M-producing K. pneumoniae isolated from patients in Bushehr province, Iran.
    Materials and Methods: A total of 212 K. pneumoniae isolates were collected and confirmed using polymerase chain reaction (PCR) of the malate dehydrogenase gene. Isolates were screened for production of ESBL. Phenotypic confirmatory test was performed using combined disk test. The genes encoding CTX-M groups and AME genes, aac(3)IIa and aac(6′)Ib, were investigated by PCR.
    Results: The ESBL phenotype was detected in 56 (26.4%) K. pneumoniae isolates. Moreover, 83.9% of ESBL-producing isolates carried the genes for CTX-M type β-lactamases, which were distributed into the two genetic groups of CTX-M-1 (97.8%)- and CTX-M-2 (2.1%)-related enzymes. Notably, among K. pneumoniae isolates containing the blaCTX-M gene, 68.08% of isolates harbored AME genes. In addition, the coexistence of blaCTX-M with aac(3)-IIa and aac(6’)-Ib was observed in 46.8% of CTX-M-producing K. pneumoniae isolates.
    Conclusion: This study provides evidence of a high prevalence of AME genes in CTX-M- producing K. pneumoniae isolates; therefore, in the initial empirical treatment of infections caused by ESBL-KP in regions with such antibiotic resistance patterns, aminoglycoside combination therapy should be undertaken carefully.

  • XML | PDF | downloads: 11 | views: 13 | pages: 171-177

    Background and Objectives: Surgical site infection (SSI) is a challenge for the surgeon. Incidence of SSI reported in literature varies from 0.5% to 15%. Severity of SSI ranges from superficial skin infection to life-threatening condition like septicaemia. It is responsible for increased morbidity, mortality, and economic burden to the hospital in general, and the patient in particular. The aim of this study was to assess the risk factors, bacteriological profile, length of hospitalization, and cost due to orthopaedic SSI in patients admitted to a tertiary care hospital.
    Materials and Methods: This was a prospective case control study. Cases were diagnosed based on CDC definition of nosocomial SSI. All cases were assessed preoperatively, intraoperatively and postoperatively, according to type of surgery, wound class, duration of operation, antimicrobial prophylaxis, use of drain, preoperative hospital stay, causative micro organism, total hospital stay, re-admission rates and cost incurred. Age, sex and surgical procedure matched controls without SSI, were also assessed. Chi- square test and Fisher's exact test were used for analysis. P= <0.05 was considered significant.
    Results: Out of 1023 patients, 47 cases had SSI, with a rate of 4.6%. Cigarette smoking was a risk factor for SSI (P = 0.0035). The most common etiologic agents were Acinetobacter baumannii and Staphylococcus aureus. Incidence of re- admission among SSI cases was more compared to controls (P= 0.0001). Costs attributable to SSI (Indian Rupees) was Rs 32,542 (17,054 to 87,514) which was significantly more than those without SSI (P= <0.001).
    Conclusion: Despite latest surgical amenities, meticulous sterilization protocols and pre-operative antibiotic prophylaxis, SSI continues to be present in healthcare settings. The increase in duration of hospital stay due to SSI adds to additional burden to an already resource-constrained healthcare system.

  • XML | PDF | downloads: 7 | views: 14 | pages: 178-182

    Background and Objectives: Antimicrobial resistance (AMR) is an increasing threat for efficient treatment of infections. Determining the epidemiology of healthcare-associated infections and causative agents in various hospital wards helps appropriate selection of antimicrobial agents.
    Materials and Methods: This retrospective study was performed by analyzing antibiograms from March 2017 to March 2018 among patients admitted to the different wards of Imam Khomeini Hospital Complex in Tehran, Iran.
    Results: Among 2440 hospital acquired infections, 59.3% were Gram-negative bacilli: E. coli (n = 469, 22.2%), K. pneumoniae (n = 457, 21.7%), Acinetobacter spp. (n = 282, 13.4%), P. aeruginosa (n = 139, 6.6%) and important Gram-positive bacteria were Enterococcus spp. (n = 216, 10.2%), S. aureus (n = 148, 7%), S. epidermidis (n = 118, 5.6). Generally, there was a high antimicrobial resistance in bacterial isolates in this study. Methicillin resistant Staphylococcus aureus (MRSA) was 56.3 % and MRSE 62.9 %. Vancomycin resistant enterococci (VRE) was 60.7%. K. pneumoniae- ESBL was 79.6% and its resistance to carbapenem was 38.4%. E. coli-ESBL was 42% and its resistance to carbapenems was 2.3%. P. aeruginosa resistance to ceftazidime was 74.4%, to fluroquinolones 63.3%, to aminoglycosides 64.8%, to piperacillin tazobactam 47.6% and to carbapenems 62.1%. Acinetobacter baumannii resistance to ceftazidime was 98.7%, to fluroquinolones 97%, to aminoglycosides 95.9%, to ampicillin sulbactam 84%, to carbapenems 96.4% and to colistin 4%.
    Conclusion: The study revealed an alarming rate of resistance to the commonly used antimicrobial agents used in treating HAIs. Also the relationship between AMR and some risk factors and thus taking steps towards controlling them have been shown.

  • XML | PDF | downloads: 9 | views: 22 | pages: 183-189

    Background and Objectives: Group B streptococcus (GBS) can cause severe and invasive infections in pregnant women, infants, and adults. This study aimed to investigate the risk factors of GBS colonization in pregnant women and determine the macrolide resistance and capsular type of isolates.
    Materials and Methods: In a cross-sectional study, a total of 200 pregnant women were screened for GBS colonization by phenotypic methods. Antibiotic susceptibility pattern of colonizing isolates and ermB, ermTR, mefA/E genes were detected. Also, molecular capsular types of isolates were distinguished.
    Results: The overall prevalence of colonization of participates with GBS was 13.5%. Statistical analysis showed that there was no association between risk factors and colonization with GBS. The highest resistance was observed to erythromycin (44.4%) followed by clindamycin (29.6%), penicillin, ampicillin, and ceftriaxone (18.5%), levofloxacin (11.1%), and 29.6% isolates were multidrug-resistant. ermTR and mefA/E genes were detected in 37% and 11.1% isolates; respectively and the ermB gene was not detected. The most common capsular type was type Ib (44.4%) followed by type III (40.7%), type II (11.1), and type Ia (3.7%).
    Conclusion: In the present study, the prevalence of GBS was in the medium range. Resistance to key antibiotic agents was relatively high. Also, capsular serotype Ib was the predominant serotype, which emphasizes the importance of monitoring the molecular typing of the GBS isolates regularly.

  • XML | PDF | downloads: 20 | views: 12 | pages: 190-198

    Background and Objectives: Some Nontuberculous Mycobacteria (NTM) can occasionally infect the human population and cause infections having symptoms similar to tuberculosis (TB). This study tried to provide updated data about the frequency and diversity of NTM species.
    Materials and Methods: Suspicious samples of Mycobacterium tuberculosis (MTB) with both positive results in Ziehl-Neelsen (ZN) staining and Löwenstein-Jensen medium culturing were evaluated during January 2016 and December 2018 in Gorgan, Iran. After determination of MTB isolates by the growth rate, pigmentation status, the niacin test, and the insertion sequence 6110 (IS6110) PCR assay, other unknown isolates (presumably NTM) were detected by the 16S rDNA sequencing method and drawing the phylogenetic tree. Based on the patients’ demographic information, their risk factors were also assessed.
    Results: Among 226 culture-positive samples, obtained from 2994 individuals with suspected symptoms of TB, the analyses found 12 (5.3%) NTM and three Mycobacterium caprae isolates. Mycobacterium simiae (6/12) was the most prevalent NTM species. The average nucleotide similarity value was 98.2% ± 3.7. In comparison to patients with MTB (211 confirmed cases), other mycobacterium infections were more common in patients over 65 years old (Odd ratio (95% convenience interval): 2.96 (0.69 - 12.59), P = 0.14).
    Conclusion: Although the NTM species has a small portion in TB suspected patients, their prevalence has increased, mainly in elderly patients. Moreover, M. simiae was the most prevalent NTM species in our region. Therefore, identification of common species in each region is recommended and clinicians should pay more attention to them in each region.

  • XML | PDF | downloads: 13 | views: 17 | pages: 199-203

    Background and Objectives: Tuberculosis is one of the main reasons for mortality in liver transplant recipients. Since Iran is considered as a tuberculosis-endemic country, the present study aims to evaluate the outcome of latent tuberculosis infection in transplant recipients after liver transplantation.
    Materials and Methods: The present analytical cross-sectional study was performed on transplanted patients in Imam Khomeini Complex Hospital in Tehran Iran from 2006 to 2016. All patients with positive tuberculin skin test were enrolled. Variables including demographic information, therapeutic and outcome data were gathered and analyzed.
    Results: Among 675 transplant recipients, 100 patients had positive tuberculin skin test (14.8%). Sixty seven percent of recipients were men and the mean age was 72.67 ± 1.3 years. All patients' received Isoniazid prophylaxis before transplantation. The mean duration of anti- tuberculosis‎ prophylaxis before and after transplant were 2.7 ± 1.9 and 3.6 ± 5.5 months, respectively. Tuberculosis has not been occurred in none of these patients after a mean follow up time of 45.21 ± 3 months. During the study period, four subjects infected by Mycobacterium tuberculosis, while their skin test was negative before transplant.
    Conclusion: According to our study, tuberculin skin test is a reliable and sensitive test for diagnosis of latent tuberculosis‎ in liver transplant candidates. Isoniazid prophylaxis is well tolerated in patients with end stage liver diseases and liver transplant recipients.

  • XML | PDF | downloads: 11 | views: 13 | pages: 204-211

    Background and Objectives: Staphylococcus aureus is a main human pathogen that causes a variety of chronic to persistent infections. Across the diverse factors of pathogenesis in bacteria, Toxin-Antitoxin (TA) systems can be considered as an antibacterial target due to their involvement in cellular physiology counting stress responses. Here, the expression of TA system genes and ClpP protease was investigated under the thermal and oxidative conditions in S. aureus strains.
    Materials and Methods: The colony-forming unit (CFU) was used to determine the effects of thermal and oxidative stresses on bacterial survival. Moreover, the expressions of TA system genes in S. aureus strains were evaluated 30 min and 1 h after thermal and oxidative stresses, respectively, by quantitative reverse transcriptase real-time PCR (qRT-PCR).
    Results: The cell viability was constant across thermal stress while oxidative stress induction showed a significantly decrease in the growth of Methicillin-Resistant S. aureus (MRSA) strain. Based on the qRT-PCR results, the expression of mazF gene increased under both thermal and oxidative stresses in the MRSA strain.
    Conclusion: A putative TA system (namely immA/irrA) most likely has a role under the stress condition of S. aureus. The MRSA strain responds to stress by shifting the expression level of TA genes that has diverse effects on the survival of the pathogen due to the stress conditions. The TA systems may be introduced as potential targets for antibacterial treatment.

  • XML | PDF | downloads: 20 | views: 21 | pages: 212-224

    Background and Objectives: Bacteriocins are considered alternative non-conventional antimicrobials produced by certain bacteria with activity against closely related species. The present study focuses on screening, characterization, and partial purification of bacteriocins produced by Staphylococcus sp. isolated from different clinical sources such as pus and blood.
    Materials and Methods: A total of 100 Staphylococcus isolates were screened for bacteriocin production using spot on lawn assay and agar diffusion method against five indicator bacteria. Bacteriocins from five selected highly active isolates were subjected to proteinase-K enzyme, different pH, and heating at different temperatures, and investigated the stabilities of their antimicrobials. Two selected isolates, MK65 and MK88, were molecularly identified by 16S rRNA gene sequencing, explored for the presence of 18 bacteriocin genes, and liquid chromatography-high resolution electrospray ionization mass spectrometry (LC-HRESIMS) was used to identify their different metabolites.
    Results: Twenty isolates exhibited inhibitory effect against at least one indicator bacteria. Micrococcus luteus ATCC 4698 showed the highest sensitivity to such bacteriocins. Proteinase K, acidic pH, and heating at 100°C triggered marked activity inhibition. However, amylase enzyme, alkaline pH, and heating at 80°C caused trivial effects. Four out of eighteen bacteriocin genes were detected using PCR. Fermentation, partial purification, and LC-HRESIMS of total protein extracts of two selected isolates, MK65 and MK88, revealed the production of different antimicrobial peptides.
    Conclusion: To the best of our knowledge, this is the first study to report the production of micrococcin and α-circulocin from Staphylococcus aureus MK65 and the production of amonabactin from Staphylococcus epidermidis MK88.

  • XML | PDF | downloads: 8 | views: 25 | pages: 225-234

    Background and Objectives: Multi-drug-resistant Enterobacter aerogenes is associated with various infectious diseases that cannot be easily treated by antibiotics. However, bacteriophages have potential therapeutic applications in the control of multi-drug-resistant bacteria. In this study, we aimed to isolate and characterize of a lytic bacteriophage that can lyse specifically the multi-drug-resistant (MDR) E. aerogenes.
    Materials and Methods: Lytic bacteriophage was isolated from Qaem hospital wastewater and characterized morphologically and genetically. Next-generation sequencing was used to complete genome analysis of the isolated bacteriophage.
    Results: Based on the transmission electron microscopy feature, the isolated bacteriophage (vB-Ea-5) belongs to the family Myoviridae. vB-Ea-5 had a latent period of 25 minutes, a burst size of 13 PFU/ml, and a burst time of 40 min. Genome sequencing revealed that vB-Ea-5 has a 135324 bp genome with 41.41% GC content. The vB-Ea-5 genome codes 212 ORFs 90 of which were categorized into several functional classes such as DNA replication and modification, transcriptional regulation, packaging, structural proteins, and a host lysis protein (Holin). No antibiotic resistance and toxin genes were detected in the genome. SDS-PAGE of vB-Ea-5 proteins exhibited three major and four minor bands with a molecular weight ranging from 18 to 50 kD.
    Conclusion: Our study suggests vB-Ea-5 as a potential candidate for phage therapy against MDR E. aerogenes infections.

  • XML | PDF | downloads: 9 | views: 19 | pages: 235-242

    Background and Objectives: Aspergillus clavatus antimicrobial peptide (AcAMP) is a fungi-derived peptide with a broad spectrum of activity against pathogenic bacteria and fungi. Natural antimicrobial peptides, including AcAMP, have attracted many attentions in the development of new natural antibiotics against pathogenic bacteria, especially multidrug resistant ones.
    Materials and Methods: In the present study, acamp gene was codon-optimized and chemically synthesized in pUC57 cloning vector, subcloned into pET28a (+) expression vector and transferred into competent Escherichia coli BL21 (DE3) cells. The expression of AcAMP was induced by addition of Isopropyl β- d-1-thiogalactopyranoside (IPTG) and the expressed peptide was purified by Ni-NTA. BALB/c mice were immunized with the purified peptide and the ability of the immunized mice sera for the detection of the native AcAMP secreted by A. clavatus IRAN 142C was examined through ELISA and Western blotting techniques.
    Results: Both ELISA and Western blotting demonstrated the ability of the sera of the immunized mice to detect the native AcAMP.
    Conclusion: The results of the present work show that the raised antibody against recombinant AcAMP can be used to detect AcAMP peptide, an issue which paves the way to develop detection kits for the detection of AcAMP-producing organisms, purification of this valuable peptide for further investigations.

  • XML | PDF | downloads: 22 | views: 21 | pages: 243-247

    Background and Objectives: Toxoplasmosis is a life threatening zoonotic infection in immunosuppressive individuals. The risk of transmission of toxoplasmosis through the blood donors isseverely high. Determining the prevalence and seropositivity rates of toxoplasmosis inasymptomatic blood donors is crucial in terms of the risk status of the transmission ofthis infection to the blood recipients.

    Materials and Methods: In this study, the presence and level of the specific Toxoplasma IgG and IgM antibodies in donors&#39; blood is investigated by
    electrochemiluminescence immunoassay (ECLIA). The statistical significance levels between Toxoplasma seropositivity and demographic characteristics of the donors such as age, educational status, raw meat consumption, drinking water supply are examined.

    Results: Toxoplasma IgG seropositivity is found among the 225 (25.6%) of the donors present inthe study group, while IgM seropositivity is detected in 20 donors (2.3%). Both IgG and IgM seropositivities are found in 12 donors (1.4%).

    Conclusion: Our study provides information about Toxoplasma seropositivity based on the samples collected from the donors who were admitted to the blood centre of a university hospital in Ankara, Turkey. This study, demonstrates that Toxoplasma seropositivity is high in the rural areas and the regions where the education level is low.

Short Communication

  • XML | PDF | downloads: 8 | views: 13 | pages: 248-251

    Background and Objectives: Brucellosis is a zoonotic disease that is caused by the Brucella species. This disease is common in Iran and its incidence is increasing .This study measures serum vitamin D levels in patients with brucellosis and healthy people.
    Materials and Methods: This research was conducted as a case-control study at Tohid Hospital, Sanandaj, Iran. The calculated sample size included 90 patients in the case group and 90 patients in the control group. The measurement of vitamin D levels in the case and control groups were performed by ELISA.
    Results: The mean serum vitamin D level was 19.91 ng/ml in the case group and 22.87 ng/ml in the control group. (Serum vitamin D level <10 ng/mL is accepted as deficiency, 10-30 ng/mL as insufficiency, 30-100 ng/mL as sufficiency, and >100 ng/mL as toxicity).
    Conclusion: There was no significant difference between the two groups in terms of vitamin D deficiency (p-value=0.097).

Case Report(s)

  • XML | PDF | downloads: 18 | views: 14 | pages: 252-256

    This study reports a 43 years-old man diagnosed with piriformis pyomyositis. A literature review was conducted by searching MEDLINE via Pubmed for English language case reports, published from 8th December 2019 to 20th January 2020. Patients' symptoms, laboratory tests, imaging, treatment, and other comorbidities were evaluated. Thirty-two cases diagnosed with piriformis pyomyositis, of which 21 patients developed piriformis abscess (including one new patient added by us) of which 52.4% were female, and the mean age was 26.98 ± 17.5. The most common manifestations were fever, lower back pain, and limited ambulation with increased ESR, CRP, or leukocytosis. Staphylococcus aureus was the most prevalent (57.14%) pathogen isolated. The authors suggested gynecologic manipulations, muscle overuse, and other co-infections as probable risk factors. However, we fail to find any association between these factors and abscess formation (p>0.05). Piriformis abscess should be regarded as a probable diagnosis in patients with gluteal pain, fever, and limited ambulation that have raised inflammatory markers or leukocytosis. MRI and CT scans are beneficial in diagnosing pyomyositis in early-stage. Full recovery is expected with timely antibiotic and surgical treatments.

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