Jundishapur Journal of Microbiology
Year:2018 | Volume:11 | Issue:4|Papers Count:7

Background: Pseudomonas aeruginosa is a Gram negative ubiquitous opportunistic organism and one of the more problematic drug-resistant pathogens encountered today. Objectives: The aims of the current multicenter research were to assess antibiotic resistance profiles, carbapenemase production, and detection of antibiotic resistance IMP gene as well as virulence factors genes including exoA, algD, lasB, and plcH among the clinical isolates of P. aeruginosa. Methods: A total of 80 nonduplicate isolates of P. aeruginosa were recovered from inpatients. Bacterial identification was done by standard diagnostic tests. Species was confirmed by detection of the exoA gene using the PCR technique. Antimicrobial susceptibility test was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Carbapenemase production among the isolates was determined by the modified Hodge test. Virulence genes were detected by PCR. Results: A total of 42 (52. 5%) isolates recovered from wound specimens. Colistin was the most effective antibiotic against isolates (97. 5% isolates were susceptible) and levofloxacin was the least effective drug (67. 5% isolates were resistant). The most common antibiotic resistance pattern was CIPR-CPMR-GEMR (47 isolates). In total, 47 (58. 75%) isolates were identified as multidrug resistance (MDR), while 30% of isolates were carbapenemase producer (MHT+). Among studied isolates, plcH+ and lasB+ genotypes (100% isolates) were the most common virulence gene patterns. Of 80 P. aeruginosa isolates, 39 (48. 75%) showed algD+, plcH+, lasB+, and IMP+ genotype. The blaIMP resistance gene was detected in all MHT positive and MDR isolates. Conclusions: In our study, theemergence of potentially highly pathogenic and carbapenem-resistant strains in joining with aMDR phenotype is alarming, as a feasible outcome would be a severe clinical result concomitant with critical restrictions in antibiotic therapy.

Background: Toll-like receptors (TLRs), especially TLR2, play an important role in the immune responses of patients with tuberculosis (TB). The prevalence of TB is estimated 38. 15 per 100, 000 population in Golestan Province, Iran, which is higher than the rates reported in other provinces. Objectives: The current study aimed at detecting Arg677Trp and Arg753Gln polymorphisms in TLR2 genes detected in patients with TB in Golestan province. Methods: A total of 130 blood samples were collected from patients with sputum smear-positive TB, and 130 blood samples were collected from healthy individuals. Twopolymorphisms of TLR2 gene, i e, Arg677TrpandArg753Gln, were investigated via polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) and sequencing methods. Results: History of corticosteroid use was more frequently reported in patients, compared to the controls, while the frequency of Bacillus calmette-guerin (BCG) vaccination was more reported in controls. PCR-SSCP analysis of the TLR2 Arg677Trp region showed an almost identical pattern for patients and controls, while 2 SSCP patterns were observed in the amplicon, related to the Arg753Gln polymorphism. DNA sequencing for the Arg677Trp polymorphism showed a duplicated pseudogene, similar to the mutant sequence (C> T), as this polymorphism cannot be considered conclusive. The Arg753Gln polymorphism was not found in the samples, although nucleotide deletion (G) was detected at position 808 among the patients. Conclusions: The Arg753Gln polymorphism was not involved in susceptibility to TB in the current study population. The presence of pseudogenes in some genes such as TLR2 necessitates careful interpretation of such studies.

Background: Anti-infective treatment has become troublesome owing to aggravated resistance to antibacterial agents. Objectives: This study aimed at investigating the distribution characteristics and drug resistance changes of pathogenic bacteria in cerebrospinal fluid (CSF) of patients with intracranial infection receiving neurosurgery, and to provide evidence for rational use of antibacterial agents. Methods: Bacteria were collected from CSF cultures of all patients receiving neurosurgery in the hospital of the current research, from January 2013 to December 2015, and the same types of strains cultured from each case during the same infection were combined. A hospital information system (HIS) was then used to analyze the data of 120 patients, who received neurosurgery from January 2015 to June 2016 and had positive CSF bacterial culture results after surgery, and to treat them by rationally selecting antibacterial agents. Results: A total of 845 pathogenic bacterial strains were isolated from the CSF samples and cultured, of which 629 were Gramnegative bacteria, accounting for 74. 4%. Particularly, Acinetobacter baumannii had severe pan-resistance. There were 216 Grampositive bacteria, which accounted for 25. 6% of all strains, and were mainly methicillin-resistant staphylococci, being basically resistant to penicillins and only susceptible to vancomycin and linezolid. After rational selection of antibacterial agents using HIS, based on the retrospective analysis results, 101 of the 120 patients were cured by vancomycin and linezolid (cure rate: 84. 17%). Conclusions: Since the treatment outcomes after rational selection of antibacterial agents (i. e. vancomycin and linezolid) using HIS were satisfactory, the findings of retrospective analysis are of high clinical value.

Background: Nowadays a number of methods are used for the extraction of genomic DNA from fecal specimens. Identification and selection of an effective DNA extraction method is considered as one of the most important steps in molecular assays of Giardia duodenalis. Objectives: We compared the effects of 3 different DNA extraction techniques in PCR amplification of a specific area of SSU rRNA gene. Methods: A total of 20 fecal samples containing purified cysts were aliquoted in 3 sub-samples. DNA extraction was performed using the Phenol-Chloroform Isoamyl alcohol (PCI), QIAamp DNA stool mini kit, and YTA Stool DNA Isolation mini Kit. The quantity and purity of extracted DNA were compared. The potency of extracted DNA was tested. Results: The results showed that the most concentrated DNA was obtained from phenol/chloroform/Isoamyl alcohol method and the best purity based on comparing the ratio of A260/230 was obtained from QIAampDNAstool mini kit. In this study the diagnostic sensitivity of QIAamp DNA stool mini kit, phenol/chloroform/Isoamyl alcohol, and YTA Stool DNA Isolation mini Kit methods was 60%, 70%, and 60%, respectively. Conclusions: The application of a proper DNA extraction method leads to obtaining reliable and reproducible results in molecular assays and supports treatment and control strategies of G. duodenalis. In this study, PCR amplification targeting a 350-bp fragment of SSUrRNA gene demonstrated phenol/chloroform/Isoamyl alcohol as the most efficient method.

Background: The development of multidrug-resistant Acinetobacter species has created serious problems in nosocomial infections. Understanding the underlying resistance mechanisms and their significance in conferring resistance to different antibiotics is the first step to develop strategies for fighting or reversing the current resistance. Objectives: The aim of this study was to investigate the role of effluxpumpsin decreasing susceptibility to amikacin in Acinetobacter clinical isolates. Methods: Forty-six clinical Acinetobacter isolates were collected from 2 teaching hospitals of Mashhad, Iran. Susceptibility testing was conducted by the disc diffusion method. Amikacinminimuminhibitory concentration (MIC) for resistant Acinetobacter isolates was determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines either with or without the efflux pumps inhibitor, carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Conventional polymerase chain reaction (PCR) was used to analyze the presence of pump genes. Results: Acinetobacter isolates were identified as 2 species; Acinetobacter baumannii and A. lwoffii. Susceptibility testing showed high levels of resistance to amikacin in 27 isolates, including both A. baumannii and A. lwoffii, among which 20 A. baumannii isolates showed a 2-to 524288-fold reduction in amikacin MIC in the presence of CCCP, while no reduction occurred in amikacin MIC in resistant A. lwoffii isolates. The PCR results showed high frequencies of adeB, abeM, and adeI genes in Acinetobacter isolates yet the adeE gene was not found in any of the isolates. Conclusions: The obtained results indicated the importance of effluxpumpsin conferring resistance to amikacin in clinical isolates of A. baumannii, yet not in A. lwoffii.

Background: A newly emerged hypervirulent strain of Klebsiella pneumoniae has caused great concern globally; however, its molecular characteristics have been rarely reported in Iran. Objectives: The goal of this study was to detect the virulence determinants and serotypes of K. pneumoniae and to evaluate the association among selected virulence traits and blaCTX-M-15 gene in southeastern Iran. Methods: One hundred and three non-duplicate K. pneumoniae strains were isolated from clinical samples. The isolates were identified by standard bacteriological tests. Confirmed isolates were examined to detect a selection of virulence genes (wabG, rmpA and iucB) and serotypes (K1, K2, K5 and K20) by PCR. The isolates were studied foe the presence of beta-lactamase (blaCTX-M-15) gene. SPSS software (version 19. 0) was used for data analysis. Results: Among the 103 K. pneumoniae isolates, 61 (59. 2%) isolates were positive for wabG, 4 (3. 9%) for iucB and 3 (2. 9%) for rmpA genes. The presence of K20 in 3. 9% (4/103) of the isolates represented the most prevalent. Only 3 (2. 9%) isolates possessed the K1 serotype, while K2 and K5 serotypes were not detected in any isolate. The blaCTX-M-15 gene was detected in 47 (45. 6%) isolates. blaCTX-M-15-positive isolates showed a higher prevalence of wabG among the studied isolates (P < 0. 05). Conclusions: Our data indicate a correlation between presence of virulence gene and blaCTX-M-15 in K. pneumonia isolates. Further research should be undertaken to unravel aspects of both virulence factors and antibiotic resistance whichmayprobably contribute to managing future spread of infectious diseases.

Background: Acanthamoeba is one of the mostcommonopportunistic free-living amoebae, with ubiquitous presence in various environmental sources. Pathogenic strains of Acanthamoeba are the causative agents of amoebic keratitisandgranulomatous amoebic encephalitis. Objectives: The aim of the present study was to identify Acanthamoeba genotypes in soil, hospital dust, and stagnant water samples from Kashan, Central Iran. Methods: In this cross sectional study, a total of 122 samples from soil (n, 32), hospital dust (n, 40), and stagnant water (n, 50) were collected and examined for the presence of free-living amoebae and Acanthamoeba species. All the samples were cultured onto non-nutrient agar plates for detection of free-living amoebae. Acanthamoeba species was identified by polymerase chain reaction (PCR) assay, using specific primers. A total of 29 Acanthamoeba isolates were sequenced, and different genotypes were detected via sequence analysis. Results: The results showed that 82. 8% (101/122) of samples were positive for free-living amoebae. The PCR assay revealed that 62. 5%, 52. 5%, and 50% of soil, hospital dust, and stagnant water samples were positive for Acanthamoeba species, respectively. Moreover, T4, T5, T2, T7, and T11 genotypes were identified. The most common genotype was T4 (76%), isolated from stagnant water. Conclusions: Acanthamoeba is a prevalent species in the soil, hospital dust, and stagnant water of Kashan. As this protozoon can cause severe infections, health education and improvement of sanitation services are recommended for prevention of infection.