Jundishapur Journal of Microbiology
Year:2017 | Volume:10 | Issue:12|Papers Count:9

Background: Invasive fungal infections without proper treatment could lead to high mortality rate, especially in immunocompromised patients. Candida species distribution and drug susceptibility patterns vary in different areas. Understanding the etiologic agents and drug susceptibility patterns in each region are required for the best management of patients with Candida infections. Objectives: The aim of this study was to identify Candida species isolated from clinical samples of six university hospitals in Iran and detect their susceptibility patterns to seven antifungal agents. Methods: Clinical samples from patients with fungal infections were cultured on Sabouraud dextrose agar. Isolated yeasts were identified by API 20C AUX kit, according to the manufacturer’ s instructions. Drug susceptibility patterns to amphotericin B, caspofungin, voriconazole, fluconazole, posaconazole, itraconazole and ketoconazole were determined, according to CLSI M27-A3 and S4. Results: In total, 428 species of Candida were isolated from clinical samples (1950 samples). Most isolated species were Candida albicans, followed by C. tropicalis, C. parapsilosis, C. kefyr, C. famata, C. glabrata, C. krusei, C. dubliniensis, C. guilliermondii and C. lusitaniae. Sensitivity rate of C. albicans to amphotericin B, caspofungin, voriconazole, fluconazole, and itraconazole was 96. 6%, 99. 5%, 88. 6%, 90. 6%, and 52% with MIC90 values equal to 0. 25  g/mL, 0. 125  g/mL, 0. 125  g/mL, 2  g/mL, and 1  g/mL, respectively. The MIC 90 values for ketoconazole and posaconazole were 0. 125 g/mL and 0. 064 g/mL, respectively. Different sensitivity to antifungal agents was present in non-albicans Candida species especially in C. krusei, C. glabrata, and C. tropicalis. Conclusions: According to this study, C. albicans is the most prevalent etiologic agent in infected patients and caspofungin is the most effective antifungal agent. Knowledge about etiologic agents and their susceptibility patterns in each region is helpful for successful treatment of the patients.

Background: Toll-like receptors (TLRs) mediate recognition of Helicobacter pylori and initiate the innate immune response to infection. Toll-like receptors polymorphisms are thought to influence susceptibility to H. pylori infection and H. pylori-related diseases. Objectives: To investigate the association of TLR polymorphisms with the susceptibility to H. pylori infection and various types of gastritis in Thai patients. Methods: The single nucleotide polymorphisms (SNPs) TLR1 rs4833095, TLR2 rs3804099 and rs3804100, TLR4 rs10759932 and TLR10 rs10004195 were analysed in 400 gastritis patients by real-time PCR using a TaqMan SNP Genotyping Assay. The association between TLR polymorphisms and the risk of H. pylori infection was investigated in 196 uninfected and 204 H. pylori-infected patients. The associations between TLR genotypes and the risk of gastric pathology changes, including chronic gastritis (N = 312 cases) and precancerous gastric lesions/gastric cancer (GC) (N = 88 cases), were examined. Univariate analysis was used to determine odds ratios (ORs) with confidence intervals (95% CIs). Results: Patients with the CC-or TT homozygous genotype for TLR1 rs4833095 had a significantly increased risk of H. pylori susceptibility (OR = 2. 28, 95% CI = 1. 27-7. 60, P = 0. 02 andOR= 1. 34, 95% CI = 0. 97-1. 86, P = 0. 04, respectively). Patients with the AA homozygous genotype for TLR10 rs10004195 had a significantly increased risk of H. pylori susceptibility (OR = 1. 28, 95% CI = 0. 98-1. 76, P = 0. 01) and exhibited a significantly increased risk of precancerous gastric lesions/GC (OR = 8. 75, 95% CI = 2. 78-14. 24, P < 0. 01). Conclusions: Our findings suggest that the TLR1 rs4833095 and TLR10 rs10004195 polymorphisms are potential genetic risk factors that modify the H. pylori infection susceptibility and influence the clinical manifestation of chronic gastritis, precancerous gastric lesions and GC in Thai patients.

Background: The clinical result severity of Helicobacter pylori infection is determined by a combination of environmental factors, host genetic background, and H. pylori virulence factors. A number of genes containing vacA, iceA, babA2, cagA, cagE, hsp60-70, and hpa have been identified to enhance H. pylori pathogenicity by encoding virulent proteins. The babA and hpa proteins are considered 2 major adhesion molecules, and thus they are key agents in the initial step of H. pylori invasion. Objectives: This study aimed at investigating the existence of babA2 and hpa virulence factors of H. pylori in Iranian patients with gastrointestinal complications. The relationship between these agents and clinical results was also investigated. Methods: A total of 80 positive biopsies out of 156 samples were studied to determine babA2 and hpa gene frequency by PCR. The positive biopsies were collected from patients suffering from gastric cancer (n =18), peptic ulcer (n = 26), and gastritis (n =36). Results: The babA2+ strains were found in 51 (64%) patients and the hpa+ strains in 57 (71%) patients were associated with sex (P = 0. 02). However, the frequency of these factors was not significant between gastric disease groups (P > 0. 05). Conclusions: Our results revealed different frequency of these virulence factors in Iran, which emphasized the effects of geographical influences. Also, it was found that male patients had higher rate of hpa than females, highlighting the gender specific factors.

Background: Most methicillin-resistant Staphylococcus aureus (MRSA) infections occur in health care settings; therefore, it is important to know about antimicrobial susceptibility, and carriage of virulence genes in S. aureus isolates. Objectives: The current study aimed at determining the prevalence of genes coding antimicrobial resistance, toxins, and adhesion factors among various SCCmec types of MRSA isolated from intensive care units (ICUs). Methods: From April 2016 to March 2017, a total of 200 MRSA species were isolated from various clinical samples of patients hospitalized in ICUs. The Kirby-Bauer disk diffusion method was employed to determine resistance pattern. Conventional polymerase chain reaction (PCR) assay was utilized to demonstrate antimicrobial resistance, toxins, and adhesion genes. Different SCCmec types of MRSA strains were determine by the multiplex PCR assay. Results: Antibiotic susceptibility testing revealed that all the isolates were sensitive to linezolid, teicoplanin, and vancomycin. The frequency of high-level mupirocin-resistant MRSA was 5. 5%. The presence of resistance genes ant(4’ )-Ia, aac(6’ )-Ie/aph(2” ), tetM, msrA, ph(3’ )-IIIa, ermA, msrB, ermB, ermC, and mupA were detected 73. 5%, 60. 5%, 57. 5%, 37%, 36. 5%, 34. 5%, 24%, 17%, 15% and 5. 5%, respectively. The most prevalent adhesion genes were clfA (93. 5%) followed by clfB (90%), fnbA (81. 5%), fnbB (77%), can (51%), ebp (46. 5%), and bbp (2. 5%). The frequency of etb, eta, pvl, and tst genes were 4. 5%, 9. 5%, 21. 5%, and 61. 5%, respectively. Inducible macrolide-lincosamidestreptogramin B (inducible MLSB resistance; iMLSB), and constitutive MLSB (cMLSB) phenotypes were observed in 88 (44%) and 26 (13%) isolates. Different SCCmec types comprising type III (56. 5%), type IV (25%), type II (11%) and type I (7. 5%) were identified among the MRSA strains. Conclusions: Results of the current studyshoweda high prevalence of resistance tocommonlyused antibiotics that can be a serious threat to patients hospitalized in ICUs. Also, the current study findings showed that different SCCmec types causing nosocomial infections were associated with specific antimicrobial resistance, adhesion, and toxin gene profiles.

Background: Acinetobacter is an opportunistic bacterial pathogen with intrinsic and acquired resistance to many antibiotics. Objectives: This study aimed to determine the prevalence of extended-spectrum -lactamases (ESBLs) and antibiotic resistance patterns in A. baumannii isolated from clinical samples atImamReza hospital in Kermanshah, Iran, using phenotypic and genotypic methods. Methods: In this descriptive-analytical study, 80 Acinetobacter isolates obtained from clinical samples were confirmed using standard biochemical tests. After antibiotic susceptibility testing using disk diffusion method, the presence of ESBLs was detected using the combined disk test (CDT). The Polymerase chain reaction (PCR) method was employed to identify the frequency of blaTEM, blaCTX-M, and blaSHV genes using their specific primers. Results: Amongthe A. baumannii isolates, 62. 5% showed multidrug resistance (MDR). The highest rate of antibiotic resistance was to ceftriaxone (100%), followed by amikacin (96. 2%), and the lowest was to polymyxin B (13. 8%) and ampicillin/sulbactam (52. 8%). Fortythree (53. 8%) ESBL-producing isolates expressing SHV (n = 18, 41. 9%), TEM (n = 11, 25. 6%), and CTX-M (n = 3, 7%) genes were identified. Conclusions: This study revealed an increased prevalence of ESBL-encoding genes in A. baumannii isolates. The increased frequency of these genes may be due to overuse or inappropriate use of antibiotics in this region. To combat overuse and prevent further development of drug resistance in Kermanshah, Iran, more attention should be paid to prescribing practices for various antibiotics, including cephalosporins.

Background: The Hepatitis E virus (HEV) infection is a serious public health problem, with a mortality rate of approximately 20-25% among pregnant women. DNA vaccination was reported to induce humoral and cellular immune responses in murine models; however, a major problem of the strategy is its limited potency. Methods: In this study, we have investigated whether Beclin1, as an autophagy-inducing based plasmid, can serve as an immunostimulatory agent and promote the HEV specific protective immunity of naked DNA vaccine encoding truncated ORF-2 (HEV239). Plasmids encoding HEV239 with or without Beclin1 were used for the BALB/c mice immunization. Results: The results demonstrated a significant increase microtubule-associated protein light chain-3 II (LC3 II) as a marker of autophagy in the HEK293 cell, which were transfected by pVITRO-Beclin1 plasmid. The immunological effects of adding Beclin1 to HEV239 ORF-2 DNA vaccines were associated with the induction of the antigen-specific lymphocyte proliferation and the Th1-type cytokine (gamma-interferon (IFN-)), while there were no differences in IL-4 levels between the groups. Examination of humoral immune responses in vaccinated mice represented that immunization with pVITRO-HEV239-Beclin1 notably increased serum level of IgG2a and total IgG against HEV in comparison to the HEV239 plasmid alone. Conclusions: The strong Th1 immune response induced by the Beclin1 suggest that induction of autophagy can be an efficient approach to enhance the immunogenicity of DNA vaccine. This promising procedure could be further exploited as a potential therapeutic vaccine candidate in future studies.

Introduction: With the widespread use of cephalosporins, Enterobacter cloacae has become an increasingly important pathogen of nosocomial infections, which causes bacterial infectious diseases involving multiple organ systems. The presence of carbapenemresistant strains has resulted in problems in the current clinical anti-infective treatment. The current study reports on four cases of carbapenem-resistant E. cloacae secretion infection in order to provide suggestions for the detection and treatment of these pathogen infections. Case Presentation: Investigation of 4 cases was conducted at tertiary care hospitals, and baseline data, treatment and outcomes were collected for patients with carbapenem-resistant E. cloacae infection. The strains of burn injury and diabetic foot infection were retrievedfromspecimens by culture-based methods, andantibiotic sensitivity testwasconductedonVitek 2. All strainsshowedminimum inhibitory concentration (MIC) values for ertapenem, imipenem, and meropenem of less than 4  g/mL. The four strains of E. cloacae produced IMP-8 type carbapenemase confirmed by PCR and sequence analysis. After the selection of reasonable antibiotic treatment, the patient‘ s condition had improved and they were discharged from the hospital. Conclusions: Low MIC value makes it difficult to detect IMP-8-harboring strains by traditional susceptibility test; molecular biology techniques may be mandatory for detection of carbapenem resistant isolates. It is very important to treat patients with reasonable antimicrobial based on susceptibility results.

Background: Hepatitis E virus (HEV) is able to induce fulminant hepatitis E infection in immunosuppressed individuals. Previous studies showed that the Baculovirus expression system (BES) could be used for developing hepatitis E virus-like particles (VLPs). Objectives: In the present study, the formation of VLPs of the recombinant proteins of HEV truncated open reading frame 2 (ORF2; 112-607) and Rotavirus non-structural protein 4 (NSP4) (OSU-a) were investigated in BES and Escherichia. coli. Methods: To construct VLPs, the truncated ORF2-NSP4 protein was expressed in BES. The expression of protein was confirmed by western blot. This protein was expressed in E. coli. The truncated ORF2-NSP4 gene was subcloned in pET28a, and then transformed into E. coli DH5 . The confirmed colonies were transformed into E. coli BL21. The solubility of protein were checked by SDS-PAGE and western blot analysis. In the final step, to verify the VLP formation in BES and E. coli, the recombinant proteins were stained with 2% uranyl acetate and checked by transmission electron microscopy (TEM). Results: The 75 KDa truncated ORF2-NSP4 protein was successfully expressed in Sf9 cells, assembled, and formed VLP according to TEM results. In the prokaryotic expression system (E. coli), the ORF2-NSP4 gene was successfully subcloned and expressed in BL21 but VLP was not detected in TEM analysis. Conclusions: The truncated ORF2-NSP4 VLP were efficiently expressed in the SF9 cells, as a potential mucosal vaccine against HEV and Rotavirus. In the prokaryotic expression system (E. coli), the ORF2-NSP4 gene was successfully expressed.

Background: Acinetobacter baumannii has appeared as an important opportunistic pathogen responsible for nosocomial infections. The rising trend of antibiotic resistance amongst A. baumannii isolates has become a global concern. The most prevalent procedure of resistance is beta-lactamase and carbapenemases production with genes on mobile elements. Objectives: The aim of the current research was to assess antibiotic susceptibility schema and the frequency of TEM, PER, and NDM-1 genes among A. baumannii isolates. Methods: One hundred and eighty three specimens from November 2014 to February 2015 were collected from Golestan and Imam Khomeini hospitals in Ahvaz, Iran. Drug susceptibility tests were carried out by Kirby-Bauer method. Extended spectrum-betalactamases (ESBLs) production was determined by the combination disk method and carbapenemases production was determined by the modified hodge test (MHT) according to the CLSI recommendations. TEM, PER, and NDM-1 were detected by PCR. Results: Out of 183 Acinetobacter isolates, 151 (82. 5 %) were identified as A. baumannii by standard chemical tests. The highest resistance was determined to ciprofloxacin (97. 3 %), whereas the higher rate of susceptibility was observed to colistin (98. 7%). 1. 3% of the A. baumannii isolates were positive for ESBL in combined disc test. Production of carbapenemase was detected in 47. 1% of the A. baumannii isolates using MHT. The prevalence of TEM and PER genes was 36. 4 % and 25. 1 %, respectively. NDM-1 genes were not detected. Conclusions: The prevalence of carbapenemase positive A. baumannii isolates in the current study makes a serious concern and highlights the need for infection control through antibiotic management protocols and rapid detection of resistant strains.