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Volume 67 (2018): Issue 4 (December 2018)

Volume 67 (2018): Issue 3 (September 2018)

Volume 67 (2018): Issue 2 (June 2018)

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Volume 66 (2017): Issue 4 (December 2017)

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Journal Details
Format
Journal
eISSN
2544-4646
First Published
04 Mar 1952
Publication timeframe
4 times per year
Languages
English

Search

Volume 67 (2018): Issue 4 (December 2018)

Journal Details
Format
Journal
eISSN
2544-4646
First Published
04 Mar 1952
Publication timeframe
4 times per year
Languages
English

Search

15 Articles

original-paper

Open Access

Emergence of High-level Gentamicin Resistance among Enterococci Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Published Online: 10 Dec 2018
Page range: 401 - 406

Abstract

Abstract

Enterococcus faecalis and Enterococcus faecium are among the main agents associated with nosocomial infections with high mortality in immunocompromised patients. Antibiotic resistance, especially against gentamicin and vancomycin among Enterococci, is a risk factor that could increase the morbidity and mortality rate. 179 Enterococci isolates from burn patients were included in this study. Antibiotic susceptibility testing was done using the disk diffusion test and minimum inhibitory concentration (MIC) was evaluated by agar microdilution. Vancomycin and gentamicin resistance associated genes including vanA, vanB, vanC, aac (6’)-Ie aph(2’’), aph(3’)-IIIa and ant(4’)-Ia were detected by PCR and their statistical relation with antibiotic resistance was evaluated. E. faecalis was the more prevalent strain among our local isolates and showed a higher antibiotic resistance in comparison to E. faecium. Vancomycin had a good antibacterial effect on the Enterococcus spp. isolates; however, resistance to this antibiotic and a high-level gentamicin resistance (HLGR) phenotype were observed. Among van operon genes, vanA was the most prevalent gene and among the gentamicin resistance genes, aph (3’)-IIIa was more frequent. The HLGR Enterococci are a real challenge in nosocomial infections. Vancomycin is a key antibiotic to treat such infections but emergence of VRE in our region could be a real concern and, therefore, phenotypic and molecular surveillance must be considered.

Keywords

  • gentamicin
  • burn
  • vancomycin
  • drug resistance
Open Access

Aspergillus penicillioides Speg. Implicated in Keratomycosis

Published Online: 10 Dec 2018
Page range: 407 - 416

Abstract

Abstract

The aim of the study was mycological examination of ulcerated corneal tissues from an ophthalmic patient. Tissue fragments were analyzed on potato-glucose agar (PDA) and maltose (MA) (Difco) media using standard laboratory techniques. Cultures were identified using classical and molecular methods. Macro- and microscopic colony morphology was characteristic of fungi from the genus Aspergillus (restricted growth series), most probably Aspergillus penicillioides Speg. Molecular analysis of the following rDNA regions: ITS1, ITS2, 5.8S, 28S rDNA, LSU and β-tubulin were carried out for the isolates studied. A high level of similarity was found between sequences from certain rDNA regions, i.e. ITS1-5.8S-ITS2 and LSU, what confirmed the classification of the isolates to the species A. penicillioides. The classification of our isolates to A. penicillioides species was confirmed also by the phylogenetic analysis.

Keywords

  • morphology
  • genetic characteristic
  • cornea
Open Access

Functional and Transcriptomic Characterization of a Dye-decolorizing Fungus from Taxus Rhizosphere

Published Online: 10 Dec 2018
Page range: 417 - 430

Abstract

Abstract

We isolated three laccase-producing fungus strains from Taxus rhizosphere. Myrotheium verrucaria strain DJTU-sh7 had the highest laccase activity of 216.2 U/ml, which was increased to above 300 U/ml after optimization. DJTU-sh7 had the best decolorizing effect for three classes of reactive dyes. The DJTU-sh7-containing fungal consortium displayed the robust decolorizing ability. Both color removal efficiency and chemical oxygen demand were increased in the consortium mediated biotransformation. Transcriptome changes of M. verrucaria elicited by azo dye and phenolic were quantified by the high throughput transcriptome sequencing, and the activities of the selected oxidases and reductases were determined. The possible involvement of oxidases and reductases, especially laccase, aryl alcohol oxidase, and ferric reductase in the biotransformation of dye and phenolic compounds was revealed at both transcriptomic and phenotypic levels. Revealing the transcriptomic mechanisms of fungi in dealing with organic pollutants facilitates the fine-tuned manipulation of strains in developing novel bioremediation and biodegradation strategies.

Keywords

  • reactive dye decolorization
  • laccase
  • transcriptome sequencing
  • degradation mechanism
Open Access

A Novel Approach to Study the Effect of Ciprofloxacin on Biofilms of Corynebacterium spp. Using Confocal Laser Scanning Microscopy

Published Online: 10 Dec 2018
Page range: 431 - 440

Abstract

Abstract

Non-diphtherial corynebacteria are Gram-positive rods that cause opportunistic infections, what is supported by their ability to produce biofilm on artificial surfaces. In this study, the characteristic of the biofilm produced on vascular and urological catheters was determined using a confocal microscopy for the most frequently involved in infections diphtheroid species. They were represented by the reference strains of Corynebacterium striatum ATCC 6940 and C. amycolatum ATCC 700207. The effect of ciprofloxacin on the biofilm produced by the antibiotic-susceptible C. striatum strain was evaluated using three concentrations of the antimicrobial agent (2 ×, 4 ×, and 6 × the MIC – the Minimum Inhibitory Concentration). The basis for the interpretation of results was the statistical analysis of maximum points readings from the surface comprising a total of 245 areas of the biofilm image under the confocal microscope. It was observed that ciprofloxacin at a concentration equal to 4 × MIC paradoxically caused an enlargement of areas with live bacteria within the biofilm. Biofilm destruction required the application of ciprofloxacin at a concentration higher than 6 × MIC. This suggests that the use of relatively low doses of antimicrobial agents may increase the number of live bacteria within the biofilm, and further facilitate their detachment from the biofilm’s structure thus leading to the spread of bacteria into the bloodstream or to the neighboring tissues. The method of biofilm analysis presented here provides the original and novel approach to the investigation of the diphtheroid biofilms and their interaction with antimicrobial agents.

Keywords

  • biofilm
  • ciprofloxacin
  • confocal microscopy
Open Access

Culturable Endophytes Diversity Isolated from Paeonia ostii and the Genetic Basis for Their Bioactivity

Published Online: 10 Dec 2018
Page range: 441 - 454

Abstract

Abstract

Paeonia ostii is known for its excellent medicinal values as Chinese traditional plant. To date, the diversity of culturable endophytes associated with P. ostii is in its initial phase of exploration. In this study, 56 endophytic bacteria and 51 endophytic fungi were isolated from P. ostii roots in China. Subsequent characterization of 56 bacterial strains by 16S rDNA gene sequence analysis revealed that nine families and 13 different genera were represented. All the fungal strains were classed into six families and 12 genera based on ITS gene sequence. The biosynthetic potential of all the endophytes was further investigated by the detection of putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes. The PCR screens were successful in targeting thirteen bacterial PKS, five bacterial NRPS, ten fungal PKS and nine fungal NRPS gene fragments. Bioinformatic analysis of these detected endophyte gene fragments facilitated inference of the potential bioactivity of endophyte bioactive products, suggesting that the isolated endophytes are capable of producing a plethora of secondary metabolites. These results suggest that endophytes isolated from P. ostii had abundant population diversity and biosynthetic potential, which further proved that endophytes are valuable reservoirs of novel bioactive compounds.

Keywords

  • endophytes
  • diversity
  • polyketide synthase
  • nonribosomal peptide synthetase
Open Access

Comparison of the Photosensitivity of Biofilms of Different Genera of Cariogenic Bacteria in Tooth Slices

Published Online: 10 Dec 2018
Page range: 455 - 462

Abstract

Abstract

This study compared the outcome of photosensitization on the viability of four different cariogens in planktonic form as well as biofilms in human dentine. Photodynamic therapy was carried out with a gallium aluminium arsenide laser (670 nm wavelength) using Toluidine blue O (TBO) as the photosensitizer. Cariogenic bacteria (Streptococcus mutans, Lactobacillus casei, Streptococcus salivarius and Actinomyces viscosus) were exposed to TBO and then to the laser for 1 minute in planktonic suspension. Then, tooth slices previously incubated for 24 hours with broth cultures of broth culture of the four cariogenic organisms were exposed to antimicrobial photosensitization. The control samples consisted of planktonic and sessile cells that were exposed to TBO alone, laser alone and the bacterial cells that were not treated with TBO or laser. The results showed significant reductions in the viability of S. mutans, L. casei and A. viscosus in both planktonic form (to 13%, 30%, and 55%, respectively) and sessile form hosted in dentinal tubules (to 19%, 13% and 52%, respectively), relative to the controls. S. salivarius was the least affected in planktonic (94% viability) and sessile form (86% viability). In conclusion, sensitivity to photosensitization is species-dependent and sessile biofilm cells are affected to the same extent as their planktonic counterparts.

Keywords

  • cariogenic bacteria
  • planktonic
  • sessile cells
  • tooth slice
  • photodynamic therapy
Open Access

Emodin Reduces the Activity of (1,3)-β-D-glucan Synthase from Candida albicans and Does Not Interact with Caspofungin

Published Online: 10 Dec 2018
Page range: 463 - 470

Abstract

Abstract

Candidiasis is the most common opportunistic yeast infection, with Candida albicans as a paramount causative species. (1,3)-β-D-glucan is one of the three main targets of clinically available antifungal agents used to treat Candida infections. It is one of the most abundant fungal cell wall components. Echinocandins represent the newest class of antifungals affecting cell wall biosynthesis through non-competitive inhibition of (1,3)-β-D-glucan synthase. Therefore, treatment with echinocandins causes defects in fungal cell integrity. In the present study, similar activity of emodin (6-methyl-1,3,8-trihydroxyanthraquinone) has been revealed. Many reports have already shown the antifungal potential of this pleiotropic molecule, including its activity against C. albicans. The aim of this report was to evaluate the activity of emodin towards a new molecular target, i.e. (1,3)-β-D-glucan synthase isolated from Candida cells. Moreover, given the identical mechanism of the activity of both molecules, interaction of emodin with caspofungin was determined. The study revealed that emodin reduced (1,3)-β-D-glucan synthase activity and increased cell wall damage, which was evidenced by both a sorbitol protection assay and an aniline blue staining assay. Furthermore, the synergy testing method showed mainly independence of the action of both tested antifungal agents, i.e. emodin and caspofungin used in combination.

Keywords

  • caspofungin
  • echinocandins
  • emodin
  • (1,3)--D-glucan synthase
Open Access

Primary and Secondary Bacteremia Caused by Proteus spp.: Epidemiology, Strains Susceptibility and Biofilm Formation

Published Online: 10 Dec 2018
Page range: 471 - 478

Abstract

Abstract

Proteus spp. is an etiological factor of urinary tract and bloodstream infections. The aim of this study was the retrospective analysis of susceptibility of Proteus spp. strains isolated from bloodstream infections (BSIs) as well as similarity evaluation of the strains isolated from different clinical samples. Proteus spp. strains were isolated in 2009–2017 from hospital patients. Identification was based on the colony’s morphology and biochemical or MALDI-TOF MS analyzes. The antibiotic susceptibility test was done using the diffusion method. Biofilm formation was evaluated with microplate method using TTC. Bacteremia caused by Proteus spp. was found in 97 patients, mainly secondary to urinary tract infection. Most of the strains were susceptible to piperacillin with tazobactam (95.9%) and amikacin (86.7%). Elderly patients have a higher risk of mortality after BSIs caused by Proteus spp. A detailed analysis was made for randomly chosen 26 strains isolated from 11 patients with Proteus mirabilis bacteremia. Using PFGE, we found that 10 (90.9%) isolates, collected from different clinical specimens of the same patient, were genetically identical.

Keywords

  • antimicrobial susceptibility
  • bacteremia
  • biofilm, spp.
Open Access

Comparison of PCR, Fluorescent in Situ Hybridization and Blood Cultures for Detection of Bacteremia in Children and Adolescents During Antibiotic Therapy

Published Online: 10 Dec 2018
Page range: 479 - 486

Abstract

Abstract

The gold standard in microbiological diagnostics of bacteremia is a blood culture in automated systems. This method may take several days and has low sensitivity. New screening methods that could quickly reveal the presence of bacteria would be extremely useful. The objective of this study was to estimate the effectiveness of these methods with respect to blood cultures in the context of antibiotic therapy. Blood samples from 92 children with sepsis were analyzed. Blood cultures were carried out in standard automated systems. Subsequently, FISH (Fluorescent In-Situ Hybridization) and nested multiplex-real-time-PCR (PCR) were performed. Blood cultures, FISH and PCR yielded positive results in 18%, 39.1%, and 71.7% of samples, respectively. Significant differences were found between the results obtained through culture before and after induction of antibiotherapy: 25.5% vs. 9.7%. There was no significant difference in FISH and PCR results in relation to antibiotics. The three methods employed demonstrated significant differences in detecting bacteria effectively. Time to obtain test results for FISH and PCR averaged 4–5 hours. FISH and PCR allow to detect bacteria in blood without prior culture. These methods had high sensitivity for the detection of bacteremia regardless of antibiotherapy. They provide more timely results as compared to automated blood culture, and may be useful as rapid screening tests in sepsis.

Keywords

  • antibiotic therapy
  • FISH
  • PCR
  • sepsis
Open Access

Drug Susceptibility of Non-tuberculous Strains of Mycobacterium Isolated from Birds from Poland

Published Online: 10 Dec 2018
Page range: 487 - 492

Abstract

Abstract

Mycobacterioses are a constant problem in backyard poultry, as well as pet birds. To date, no evidence of direct transmission of atypical bacilli between humans has been demonstrated, but it cannot be ruled out that sick animals can be a source of infection for people in their environment. The aim of the study was to identify mycobacteria isolated from birds with diagnosed mycobacteriosis and to determine the susceptibility of mycobacterial isolates from these animals to antituberculous drugs most commonly used in the treatment of mycobacterial infections in humans. For drug susceptibility tests, drugs such as isoniazid, rifampicin, streptomycin, ethambutol, ofloxacin, capreomycin, cycloserine and ethionamide were used. A high degree of drug resistance was demonstrated, particularly in Mycobacterium avium. Isolates of Mycobacterium xenopi showed a relatively good susceptibility to the drugs tested. The drug resistance of Mycobacterium genavense has not been determined, but this mycobacterium was identified in ten cases, which is the second most frequent occurrence in the cases studied.

Keywords

  • avian mycobacteriosis
  • mycobacteriosis
  • drug susceptibility tests
Open Access

Evaluation of Neisseria meningitidis Carriage with the Analysis of Serogroups, Genogroups and Clonal Complexes among Polish Soldiers

Published Online: 10 Dec 2018
Page range: 493 - 500

Abstract

Abstract

Neisseria meningitidis is an etiological factor of invasive meningococcal disease (IMD). This Gram-negative diplococcus is transmitted from person to person via droplets or through a direct physical contact with secretions of infected patients or asymptomatic carriers. The latter account for 5–10% of the general population. The aim of the study was to estimate the actual N. meningitidis carriage rate in the military environment with identification of serogroups, genogroups, sequence types and clonal complexes of the isolates detected among Polish soldiers. The study was conducted during winter seasons of 2015 and 2016 and involved 883 professional soldiers from the Armoured Brigade in Świętoszów, Poland. The material for testing were nasopharyngeal swabs obtained from study participants. The samples were tested using standard microbiological methods (culture, incubation, microscopy, biochemical and automated identification). N. meningitidis isolates were subjected to slide agglutination test (identification of serogroups), the bacterial DNA was extracted and allowed to determine genogroups, clonal complexes and sequence types. 76 soldiers were found to be carriers of N. meningitidis, they accounted for 8.6% of the study group. The meningococcal isolates mostly belonged to serogroup B. Sequence types ST-11439, ST-136, ST-1136 and the clonal complex 41/44CC were found to be predominant. Clonal complexes responsible for IMD were detected in 15.8% of carriers and 1.4% of the whole study participants. Carriage rates of N. meningitidis among Polish soldiers were found to be similar to those reported in the general population.

Keywords

  • serogroups
  • genogroups
  • clonal complexes
  • soldiers
Open Access

Epilithic Biofilms in Lake Baikal: Screening and Diversity of PKS and NRPS Genes in the Genomes of Heterotrophic Bacteria

Published Online: 10 Dec 2018
Page range: 501 - 516

Abstract

Abstract

A collection of heterotrophic bacteria consisting of 167 strains was obtained from microbial communities of biofilms formed on solid substrates in the littoral zone of Lake Baikal. Based on the analysis of 16S rRNA gene fragments, the isolates were classified to four phyla: Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. To assess their biotechnological potential, bacteria were screened for the presence of PKS (polyketide synthase) and NRPS (non-ribosomal peptide synthetases) genes. PKS genes were detected in 41 strains (25%) and NRPS genes in 73 (43%) strains by PCR analysis. The occurrence of PKS genes in members of the phylum Firmicutes (the genera Bacillus and Paenibacillus) was 34% and NRPS genes were found in 78%. In Proteobacteria, PKS and NRPS genes were found in 20% and 32%, and in 22% and 22% of Actinobacteria, respectively. For further analysis of PKS and NRPS genes, six Bacillus and Paenibacillus strains with antagonistic activity were selected and underwent phylogenetic analysis of 16S rRNA genes. The identification of PKS and NRPS genes in the strains investigated was demonstrated among the homologues the genes involved in the biosynthesis of antibiotics (bacillaene, difficidine, erythromycin, bacitracin, tridecaptin, and fusaricidin), biosurfactants (iturin, bacillomycin, plipastatin, fengycin, and surfactin) and antitumor agents (epothilone, calyculin, and briostatin). Bacillus spp. 9A and 2A strains showed the highest diversity of PKS and NRPS genes. Bacillus and Paenibacillus strains isolated from epilithic biofilms in Lake Baikal are potential producers of antimicrobial compounds and may be of practical interest for biotechnological purposes.

Keywords

  • polyketide synthase genes
  • non-ribosomal peptide synthetases
  • epilithic biofilms
  • Lake Baikal
  • secondary metabolites
Open Access

Microbiology and Drug Resistance of Pathogens in Patients Hospitalized at the Nephrology Department in the South of Poland

Published Online: 10 Dec 2018
Page range: 517 - 524

Abstract

Abstract

A retrospective study was conducted among 498 patients with urinary tract infections (UTI) referred to our department from January 2013 to December 2015. This study was performed to evaluate the etiology of UTI and the antibiotic susceptibility profile of Escherichia coli (E. coli) as the main etiological factor in different age groups. Urine samples were examined using standard microbiological methods. Three hundred sixty-three samples (72.9%) were identified as E. coli, of which 29 (8.0%) can produce extended-spectrum β-lactamases (ESBL). E. coli was highly sensitive to imipenem (100.0%), gentamicin (91.0%), nitrofurantoin (89.4%), amikacin (88.2%), piperacillin/ tazobactam (87.0%) and cephalosporins (79.7–89.5%). Low sensitivity was found in relation to fluoroquinolones (60.3–70.4%). E. coli was least sensitive to ampicillin (30.2%) and amoxicillin/clavulanic acid (49.9%). We observed a significant fall in susceptibility level to piperacillin/tazobactam (68.4% vs. 88.8%; p = 0.017), amikacin (61.1% vs. 90.7%; p = 0.001), gentamicin (70.0% vs. 93.2%; p = 0.002), cefalexin (41.2% vs. 83.3%; p < 0.001), cefotaxime (63.6% vs. 89.4%; p = 0.002), ceftazidime (61.9% vs. 85.6%; p = 0.008), cefepime (73.7% vs. 91.1%; p = 0.025), ciprofloxacin (54.1% vs. 72.2%; p = 0.024) and norfloxacin (40.5% vs. 62.5%; p = 0.011) among patients with catheter-associated UTI (CAUTI) compared to those with non-CAUTI. A similar susceptibility profile was observed between different age groups. In the longevity, E. coli showed a higher sensitivity to cephalosporins than in the young-old group. E. coli susceptibility to fluoroquinolones was low, which excludes them as a first-line drug in our department. Nitrofurantoin may be used as an alternative drug to carbapenems. Monitoring of susceptibility pattern is of great importance.

Keywords

  • urinary tract infection (UTI)
  • antimicrobial susceptibility testing (AST)
Open Access

A Special Risk Group for Hepatitis E Infection: The First Record of North Cyprus

Published Online: 10 Dec 2018
Page range: 525 - 528

Abstract

Abstract

Hepatitis E virus (HEV) is transmitted by a fecal oral route from animals to humans following exposure to the body fluids of infected animals. We investigated the seroprevalence of anti-hepatitis E (anti-HEV) antibodies by monitoring IgG and IgM virus antibodies amongst employees in the animal industry in North Cyprus through a cross-sectional study. Samples were taken from individuals without occupational exposure to animals and from those who worked with animals (doing animal husbandry, veterinary work or butchery). Enzyme-linked immunoassays were used to detect anti-HEV IgG and IgM in the blood samples. The prevalence of anti-HEV IgG antibodies was 3.0% (12/400), while the prevalence of anti-HEV IgM antibodies was 0.25% (1/400). The prevalence of anti-HEV IgG amongst the samples received from females was approximately 2.5-fold higher than samples received from males (2.4%). Anti-HEV IgG was detected amongst 7% of animal husbandry workers and amongst 2% of veterinarians and butchers. The current findings represent the first records of HEV surveillance in Cyprus. We investigated the seroprevalence of anti-HEV by monitoring IgG and IgM virus antibodies amongst employees.

Keywords

  • Cyprus
  • hepatitis E
  • seroprevalence
  • zoonoses
  • animals
  • epidemiology

short-communication

Open Access

Detection of Coxiella burnetii and Francisella tularensis in Tissues of Wild-living Animals and in Ticks of North-west Poland

Published Online: 10 Dec 2018
Page range: 529 - 534

Abstract

Abstract

This work presents results of the research on the occurrence of Coxiella burnetii and Francisella tularensis in the tissues of wild-living animals and ticks collected from Drawsko County, West Pomeranian Voivodeship. The real-time PCR testing for the pathogens comprised 928 samples of animal internal organs and 1551 ticks. The presence of C. burnetii was detected in 3% of wild-living animals and in 0.45–3.45% (dependent on collection areas) of ticks. The genetic sequences of F. tularensis were present in 0.49 % of ticks (only in one location – Drawa) and were not detected in animal tissues. The results indicate respectively low proportion of animals and ticks infected with C. burnetii and F. tularensis.

Keywords

  • reservoirs
  • real-time PCR
15 Articles

original-paper

Open Access

Emergence of High-level Gentamicin Resistance among Enterococci Clinical Isolates from Burn Patients in South-west of Iran: Vancomycin Still Working

Published Online: 10 Dec 2018
Page range: 401 - 406

Abstract

Abstract

Enterococcus faecalis and Enterococcus faecium are among the main agents associated with nosocomial infections with high mortality in immunocompromised patients. Antibiotic resistance, especially against gentamicin and vancomycin among Enterococci, is a risk factor that could increase the morbidity and mortality rate. 179 Enterococci isolates from burn patients were included in this study. Antibiotic susceptibility testing was done using the disk diffusion test and minimum inhibitory concentration (MIC) was evaluated by agar microdilution. Vancomycin and gentamicin resistance associated genes including vanA, vanB, vanC, aac (6’)-Ie aph(2’’), aph(3’)-IIIa and ant(4’)-Ia were detected by PCR and their statistical relation with antibiotic resistance was evaluated. E. faecalis was the more prevalent strain among our local isolates and showed a higher antibiotic resistance in comparison to E. faecium. Vancomycin had a good antibacterial effect on the Enterococcus spp. isolates; however, resistance to this antibiotic and a high-level gentamicin resistance (HLGR) phenotype were observed. Among van operon genes, vanA was the most prevalent gene and among the gentamicin resistance genes, aph (3’)-IIIa was more frequent. The HLGR Enterococci are a real challenge in nosocomial infections. Vancomycin is a key antibiotic to treat such infections but emergence of VRE in our region could be a real concern and, therefore, phenotypic and molecular surveillance must be considered.

Keywords

  • gentamicin
  • burn
  • vancomycin
  • drug resistance
Open Access

Aspergillus penicillioides Speg. Implicated in Keratomycosis

Published Online: 10 Dec 2018
Page range: 407 - 416

Abstract

Abstract

The aim of the study was mycological examination of ulcerated corneal tissues from an ophthalmic patient. Tissue fragments were analyzed on potato-glucose agar (PDA) and maltose (MA) (Difco) media using standard laboratory techniques. Cultures were identified using classical and molecular methods. Macro- and microscopic colony morphology was characteristic of fungi from the genus Aspergillus (restricted growth series), most probably Aspergillus penicillioides Speg. Molecular analysis of the following rDNA regions: ITS1, ITS2, 5.8S, 28S rDNA, LSU and β-tubulin were carried out for the isolates studied. A high level of similarity was found between sequences from certain rDNA regions, i.e. ITS1-5.8S-ITS2 and LSU, what confirmed the classification of the isolates to the species A. penicillioides. The classification of our isolates to A. penicillioides species was confirmed also by the phylogenetic analysis.

Keywords

  • morphology
  • genetic characteristic
  • cornea
Open Access

Functional and Transcriptomic Characterization of a Dye-decolorizing Fungus from Taxus Rhizosphere

Published Online: 10 Dec 2018
Page range: 417 - 430

Abstract

Abstract

We isolated three laccase-producing fungus strains from Taxus rhizosphere. Myrotheium verrucaria strain DJTU-sh7 had the highest laccase activity of 216.2 U/ml, which was increased to above 300 U/ml after optimization. DJTU-sh7 had the best decolorizing effect for three classes of reactive dyes. The DJTU-sh7-containing fungal consortium displayed the robust decolorizing ability. Both color removal efficiency and chemical oxygen demand were increased in the consortium mediated biotransformation. Transcriptome changes of M. verrucaria elicited by azo dye and phenolic were quantified by the high throughput transcriptome sequencing, and the activities of the selected oxidases and reductases were determined. The possible involvement of oxidases and reductases, especially laccase, aryl alcohol oxidase, and ferric reductase in the biotransformation of dye and phenolic compounds was revealed at both transcriptomic and phenotypic levels. Revealing the transcriptomic mechanisms of fungi in dealing with organic pollutants facilitates the fine-tuned manipulation of strains in developing novel bioremediation and biodegradation strategies.

Keywords

  • reactive dye decolorization
  • laccase
  • transcriptome sequencing
  • degradation mechanism
Open Access

A Novel Approach to Study the Effect of Ciprofloxacin on Biofilms of Corynebacterium spp. Using Confocal Laser Scanning Microscopy

Published Online: 10 Dec 2018
Page range: 431 - 440

Abstract

Abstract

Non-diphtherial corynebacteria are Gram-positive rods that cause opportunistic infections, what is supported by their ability to produce biofilm on artificial surfaces. In this study, the characteristic of the biofilm produced on vascular and urological catheters was determined using a confocal microscopy for the most frequently involved in infections diphtheroid species. They were represented by the reference strains of Corynebacterium striatum ATCC 6940 and C. amycolatum ATCC 700207. The effect of ciprofloxacin on the biofilm produced by the antibiotic-susceptible C. striatum strain was evaluated using three concentrations of the antimicrobial agent (2 ×, 4 ×, and 6 × the MIC – the Minimum Inhibitory Concentration). The basis for the interpretation of results was the statistical analysis of maximum points readings from the surface comprising a total of 245 areas of the biofilm image under the confocal microscope. It was observed that ciprofloxacin at a concentration equal to 4 × MIC paradoxically caused an enlargement of areas with live bacteria within the biofilm. Biofilm destruction required the application of ciprofloxacin at a concentration higher than 6 × MIC. This suggests that the use of relatively low doses of antimicrobial agents may increase the number of live bacteria within the biofilm, and further facilitate their detachment from the biofilm’s structure thus leading to the spread of bacteria into the bloodstream or to the neighboring tissues. The method of biofilm analysis presented here provides the original and novel approach to the investigation of the diphtheroid biofilms and their interaction with antimicrobial agents.

Keywords

  • biofilm
  • ciprofloxacin
  • confocal microscopy
Open Access

Culturable Endophytes Diversity Isolated from Paeonia ostii and the Genetic Basis for Their Bioactivity

Published Online: 10 Dec 2018
Page range: 441 - 454

Abstract

Abstract

Paeonia ostii is known for its excellent medicinal values as Chinese traditional plant. To date, the diversity of culturable endophytes associated with P. ostii is in its initial phase of exploration. In this study, 56 endophytic bacteria and 51 endophytic fungi were isolated from P. ostii roots in China. Subsequent characterization of 56 bacterial strains by 16S rDNA gene sequence analysis revealed that nine families and 13 different genera were represented. All the fungal strains were classed into six families and 12 genera based on ITS gene sequence. The biosynthetic potential of all the endophytes was further investigated by the detection of putative polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) genes. The PCR screens were successful in targeting thirteen bacterial PKS, five bacterial NRPS, ten fungal PKS and nine fungal NRPS gene fragments. Bioinformatic analysis of these detected endophyte gene fragments facilitated inference of the potential bioactivity of endophyte bioactive products, suggesting that the isolated endophytes are capable of producing a plethora of secondary metabolites. These results suggest that endophytes isolated from P. ostii had abundant population diversity and biosynthetic potential, which further proved that endophytes are valuable reservoirs of novel bioactive compounds.

Keywords

  • endophytes
  • diversity
  • polyketide synthase
  • nonribosomal peptide synthetase
Open Access

Comparison of the Photosensitivity of Biofilms of Different Genera of Cariogenic Bacteria in Tooth Slices

Published Online: 10 Dec 2018
Page range: 455 - 462

Abstract

Abstract

This study compared the outcome of photosensitization on the viability of four different cariogens in planktonic form as well as biofilms in human dentine. Photodynamic therapy was carried out with a gallium aluminium arsenide laser (670 nm wavelength) using Toluidine blue O (TBO) as the photosensitizer. Cariogenic bacteria (Streptococcus mutans, Lactobacillus casei, Streptococcus salivarius and Actinomyces viscosus) were exposed to TBO and then to the laser for 1 minute in planktonic suspension. Then, tooth slices previously incubated for 24 hours with broth cultures of broth culture of the four cariogenic organisms were exposed to antimicrobial photosensitization. The control samples consisted of planktonic and sessile cells that were exposed to TBO alone, laser alone and the bacterial cells that were not treated with TBO or laser. The results showed significant reductions in the viability of S. mutans, L. casei and A. viscosus in both planktonic form (to 13%, 30%, and 55%, respectively) and sessile form hosted in dentinal tubules (to 19%, 13% and 52%, respectively), relative to the controls. S. salivarius was the least affected in planktonic (94% viability) and sessile form (86% viability). In conclusion, sensitivity to photosensitization is species-dependent and sessile biofilm cells are affected to the same extent as their planktonic counterparts.

Keywords

  • cariogenic bacteria
  • planktonic
  • sessile cells
  • tooth slice
  • photodynamic therapy
Open Access

Emodin Reduces the Activity of (1,3)-β-D-glucan Synthase from Candida albicans and Does Not Interact with Caspofungin

Published Online: 10 Dec 2018
Page range: 463 - 470

Abstract

Abstract

Candidiasis is the most common opportunistic yeast infection, with Candida albicans as a paramount causative species. (1,3)-β-D-glucan is one of the three main targets of clinically available antifungal agents used to treat Candida infections. It is one of the most abundant fungal cell wall components. Echinocandins represent the newest class of antifungals affecting cell wall biosynthesis through non-competitive inhibition of (1,3)-β-D-glucan synthase. Therefore, treatment with echinocandins causes defects in fungal cell integrity. In the present study, similar activity of emodin (6-methyl-1,3,8-trihydroxyanthraquinone) has been revealed. Many reports have already shown the antifungal potential of this pleiotropic molecule, including its activity against C. albicans. The aim of this report was to evaluate the activity of emodin towards a new molecular target, i.e. (1,3)-β-D-glucan synthase isolated from Candida cells. Moreover, given the identical mechanism of the activity of both molecules, interaction of emodin with caspofungin was determined. The study revealed that emodin reduced (1,3)-β-D-glucan synthase activity and increased cell wall damage, which was evidenced by both a sorbitol protection assay and an aniline blue staining assay. Furthermore, the synergy testing method showed mainly independence of the action of both tested antifungal agents, i.e. emodin and caspofungin used in combination.

Keywords

  • caspofungin
  • echinocandins
  • emodin
  • (1,3)--D-glucan synthase
Open Access

Primary and Secondary Bacteremia Caused by Proteus spp.: Epidemiology, Strains Susceptibility and Biofilm Formation

Published Online: 10 Dec 2018
Page range: 471 - 478

Abstract

Abstract

Proteus spp. is an etiological factor of urinary tract and bloodstream infections. The aim of this study was the retrospective analysis of susceptibility of Proteus spp. strains isolated from bloodstream infections (BSIs) as well as similarity evaluation of the strains isolated from different clinical samples. Proteus spp. strains were isolated in 2009–2017 from hospital patients. Identification was based on the colony’s morphology and biochemical or MALDI-TOF MS analyzes. The antibiotic susceptibility test was done using the diffusion method. Biofilm formation was evaluated with microplate method using TTC. Bacteremia caused by Proteus spp. was found in 97 patients, mainly secondary to urinary tract infection. Most of the strains were susceptible to piperacillin with tazobactam (95.9%) and amikacin (86.7%). Elderly patients have a higher risk of mortality after BSIs caused by Proteus spp. A detailed analysis was made for randomly chosen 26 strains isolated from 11 patients with Proteus mirabilis bacteremia. Using PFGE, we found that 10 (90.9%) isolates, collected from different clinical specimens of the same patient, were genetically identical.

Keywords

  • antimicrobial susceptibility
  • bacteremia
  • biofilm, spp.
Open Access

Comparison of PCR, Fluorescent in Situ Hybridization and Blood Cultures for Detection of Bacteremia in Children and Adolescents During Antibiotic Therapy

Published Online: 10 Dec 2018
Page range: 479 - 486

Abstract

Abstract

The gold standard in microbiological diagnostics of bacteremia is a blood culture in automated systems. This method may take several days and has low sensitivity. New screening methods that could quickly reveal the presence of bacteria would be extremely useful. The objective of this study was to estimate the effectiveness of these methods with respect to blood cultures in the context of antibiotic therapy. Blood samples from 92 children with sepsis were analyzed. Blood cultures were carried out in standard automated systems. Subsequently, FISH (Fluorescent In-Situ Hybridization) and nested multiplex-real-time-PCR (PCR) were performed. Blood cultures, FISH and PCR yielded positive results in 18%, 39.1%, and 71.7% of samples, respectively. Significant differences were found between the results obtained through culture before and after induction of antibiotherapy: 25.5% vs. 9.7%. There was no significant difference in FISH and PCR results in relation to antibiotics. The three methods employed demonstrated significant differences in detecting bacteria effectively. Time to obtain test results for FISH and PCR averaged 4–5 hours. FISH and PCR allow to detect bacteria in blood without prior culture. These methods had high sensitivity for the detection of bacteremia regardless of antibiotherapy. They provide more timely results as compared to automated blood culture, and may be useful as rapid screening tests in sepsis.

Keywords

  • antibiotic therapy
  • FISH
  • PCR
  • sepsis
Open Access

Drug Susceptibility of Non-tuberculous Strains of Mycobacterium Isolated from Birds from Poland

Published Online: 10 Dec 2018
Page range: 487 - 492

Abstract

Abstract

Mycobacterioses are a constant problem in backyard poultry, as well as pet birds. To date, no evidence of direct transmission of atypical bacilli between humans has been demonstrated, but it cannot be ruled out that sick animals can be a source of infection for people in their environment. The aim of the study was to identify mycobacteria isolated from birds with diagnosed mycobacteriosis and to determine the susceptibility of mycobacterial isolates from these animals to antituberculous drugs most commonly used in the treatment of mycobacterial infections in humans. For drug susceptibility tests, drugs such as isoniazid, rifampicin, streptomycin, ethambutol, ofloxacin, capreomycin, cycloserine and ethionamide were used. A high degree of drug resistance was demonstrated, particularly in Mycobacterium avium. Isolates of Mycobacterium xenopi showed a relatively good susceptibility to the drugs tested. The drug resistance of Mycobacterium genavense has not been determined, but this mycobacterium was identified in ten cases, which is the second most frequent occurrence in the cases studied.

Keywords

  • avian mycobacteriosis
  • mycobacteriosis
  • drug susceptibility tests
Open Access

Evaluation of Neisseria meningitidis Carriage with the Analysis of Serogroups, Genogroups and Clonal Complexes among Polish Soldiers

Published Online: 10 Dec 2018
Page range: 493 - 500

Abstract

Abstract

Neisseria meningitidis is an etiological factor of invasive meningococcal disease (IMD). This Gram-negative diplococcus is transmitted from person to person via droplets or through a direct physical contact with secretions of infected patients or asymptomatic carriers. The latter account for 5–10% of the general population. The aim of the study was to estimate the actual N. meningitidis carriage rate in the military environment with identification of serogroups, genogroups, sequence types and clonal complexes of the isolates detected among Polish soldiers. The study was conducted during winter seasons of 2015 and 2016 and involved 883 professional soldiers from the Armoured Brigade in Świętoszów, Poland. The material for testing were nasopharyngeal swabs obtained from study participants. The samples were tested using standard microbiological methods (culture, incubation, microscopy, biochemical and automated identification). N. meningitidis isolates were subjected to slide agglutination test (identification of serogroups), the bacterial DNA was extracted and allowed to determine genogroups, clonal complexes and sequence types. 76 soldiers were found to be carriers of N. meningitidis, they accounted for 8.6% of the study group. The meningococcal isolates mostly belonged to serogroup B. Sequence types ST-11439, ST-136, ST-1136 and the clonal complex 41/44CC were found to be predominant. Clonal complexes responsible for IMD were detected in 15.8% of carriers and 1.4% of the whole study participants. Carriage rates of N. meningitidis among Polish soldiers were found to be similar to those reported in the general population.

Keywords

  • serogroups
  • genogroups
  • clonal complexes
  • soldiers
Open Access

Epilithic Biofilms in Lake Baikal: Screening and Diversity of PKS and NRPS Genes in the Genomes of Heterotrophic Bacteria

Published Online: 10 Dec 2018
Page range: 501 - 516

Abstract

Abstract

A collection of heterotrophic bacteria consisting of 167 strains was obtained from microbial communities of biofilms formed on solid substrates in the littoral zone of Lake Baikal. Based on the analysis of 16S rRNA gene fragments, the isolates were classified to four phyla: Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. To assess their biotechnological potential, bacteria were screened for the presence of PKS (polyketide synthase) and NRPS (non-ribosomal peptide synthetases) genes. PKS genes were detected in 41 strains (25%) and NRPS genes in 73 (43%) strains by PCR analysis. The occurrence of PKS genes in members of the phylum Firmicutes (the genera Bacillus and Paenibacillus) was 34% and NRPS genes were found in 78%. In Proteobacteria, PKS and NRPS genes were found in 20% and 32%, and in 22% and 22% of Actinobacteria, respectively. For further analysis of PKS and NRPS genes, six Bacillus and Paenibacillus strains with antagonistic activity were selected and underwent phylogenetic analysis of 16S rRNA genes. The identification of PKS and NRPS genes in the strains investigated was demonstrated among the homologues the genes involved in the biosynthesis of antibiotics (bacillaene, difficidine, erythromycin, bacitracin, tridecaptin, and fusaricidin), biosurfactants (iturin, bacillomycin, plipastatin, fengycin, and surfactin) and antitumor agents (epothilone, calyculin, and briostatin). Bacillus spp. 9A and 2A strains showed the highest diversity of PKS and NRPS genes. Bacillus and Paenibacillus strains isolated from epilithic biofilms in Lake Baikal are potential producers of antimicrobial compounds and may be of practical interest for biotechnological purposes.

Keywords

  • polyketide synthase genes
  • non-ribosomal peptide synthetases
  • epilithic biofilms
  • Lake Baikal
  • secondary metabolites
Open Access

Microbiology and Drug Resistance of Pathogens in Patients Hospitalized at the Nephrology Department in the South of Poland

Published Online: 10 Dec 2018
Page range: 517 - 524

Abstract

Abstract

A retrospective study was conducted among 498 patients with urinary tract infections (UTI) referred to our department from January 2013 to December 2015. This study was performed to evaluate the etiology of UTI and the antibiotic susceptibility profile of Escherichia coli (E. coli) as the main etiological factor in different age groups. Urine samples were examined using standard microbiological methods. Three hundred sixty-three samples (72.9%) were identified as E. coli, of which 29 (8.0%) can produce extended-spectrum β-lactamases (ESBL). E. coli was highly sensitive to imipenem (100.0%), gentamicin (91.0%), nitrofurantoin (89.4%), amikacin (88.2%), piperacillin/ tazobactam (87.0%) and cephalosporins (79.7–89.5%). Low sensitivity was found in relation to fluoroquinolones (60.3–70.4%). E. coli was least sensitive to ampicillin (30.2%) and amoxicillin/clavulanic acid (49.9%). We observed a significant fall in susceptibility level to piperacillin/tazobactam (68.4% vs. 88.8%; p = 0.017), amikacin (61.1% vs. 90.7%; p = 0.001), gentamicin (70.0% vs. 93.2%; p = 0.002), cefalexin (41.2% vs. 83.3%; p < 0.001), cefotaxime (63.6% vs. 89.4%; p = 0.002), ceftazidime (61.9% vs. 85.6%; p = 0.008), cefepime (73.7% vs. 91.1%; p = 0.025), ciprofloxacin (54.1% vs. 72.2%; p = 0.024) and norfloxacin (40.5% vs. 62.5%; p = 0.011) among patients with catheter-associated UTI (CAUTI) compared to those with non-CAUTI. A similar susceptibility profile was observed between different age groups. In the longevity, E. coli showed a higher sensitivity to cephalosporins than in the young-old group. E. coli susceptibility to fluoroquinolones was low, which excludes them as a first-line drug in our department. Nitrofurantoin may be used as an alternative drug to carbapenems. Monitoring of susceptibility pattern is of great importance.

Keywords

  • urinary tract infection (UTI)
  • antimicrobial susceptibility testing (AST)
Open Access

A Special Risk Group for Hepatitis E Infection: The First Record of North Cyprus

Published Online: 10 Dec 2018
Page range: 525 - 528

Abstract

Abstract

Hepatitis E virus (HEV) is transmitted by a fecal oral route from animals to humans following exposure to the body fluids of infected animals. We investigated the seroprevalence of anti-hepatitis E (anti-HEV) antibodies by monitoring IgG and IgM virus antibodies amongst employees in the animal industry in North Cyprus through a cross-sectional study. Samples were taken from individuals without occupational exposure to animals and from those who worked with animals (doing animal husbandry, veterinary work or butchery). Enzyme-linked immunoassays were used to detect anti-HEV IgG and IgM in the blood samples. The prevalence of anti-HEV IgG antibodies was 3.0% (12/400), while the prevalence of anti-HEV IgM antibodies was 0.25% (1/400). The prevalence of anti-HEV IgG amongst the samples received from females was approximately 2.5-fold higher than samples received from males (2.4%). Anti-HEV IgG was detected amongst 7% of animal husbandry workers and amongst 2% of veterinarians and butchers. The current findings represent the first records of HEV surveillance in Cyprus. We investigated the seroprevalence of anti-HEV by monitoring IgG and IgM virus antibodies amongst employees.

Keywords

  • Cyprus
  • hepatitis E
  • seroprevalence
  • zoonoses
  • animals
  • epidemiology

short-communication

Open Access

Detection of Coxiella burnetii and Francisella tularensis in Tissues of Wild-living Animals and in Ticks of North-west Poland

Published Online: 10 Dec 2018
Page range: 529 - 534

Abstract

Abstract

This work presents results of the research on the occurrence of Coxiella burnetii and Francisella tularensis in the tissues of wild-living animals and ticks collected from Drawsko County, West Pomeranian Voivodeship. The real-time PCR testing for the pathogens comprised 928 samples of animal internal organs and 1551 ticks. The presence of C. burnetii was detected in 3% of wild-living animals and in 0.45–3.45% (dependent on collection areas) of ticks. The genetic sequences of F. tularensis were present in 0.49 % of ticks (only in one location – Drawa) and were not detected in animal tissues. The results indicate respectively low proportion of animals and ticks infected with C. burnetii and F. tularensis.

Keywords

  • reservoirs
  • real-time PCR

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