PCR diagnostic system in the treatment of prosthetic joint infections

In our prospective study, we examined whether a multiplex PCR diagnostic method is suitable for the primary detection of pathogens. We also examined the possibility and sensitivity of detecting genes responsible for biofilm production and methicillin resistance. From 2007 to 2009, 94 patients were included in the study. A UNB (universal detection of 16S ribosomal bacterial DNA) and UNF (universal detection of pathogenic fungi) were used in the primary detection. A multiplex assay for biofilm production, methicillin resistance allowed us to distinguish between Gram positivity and negativity and to detect Staphylococci. From all the samples, the culture was positive in 53.2 % of cases, and by using the UNB method, we detected bacteria in 79.8 % of cases-the UNF detection of fungi was positive in 10.6 % of cases. In 75 % of positive findings, we detected a Gram-negative bacterium in 65.3 % of cases. In 47.2 % of Staphylococci detected, the ability to produce biofilm was confirmed. 61.1 % of the Staphylococci exhibited a methicillin resistance. Our multiplex scheme cannot yet fully replace microbial cultivation but can be a rational guide when choosing an appropriate antibiotic therapy in cases where the microbial culture is negative.

A combined AFLP-multiplex PCR assay for molecular typing of Escherichia coli strains using variable bacterial interspersed mosaic elements

The original method for molecular typing of E. coli strains was developed using the polymorphism in chromosomal sequences of bacterial interspersed mosaic elements (BIMEs) detected by multiplex PCR and analysed by AFLP assay. The applicability of the method in the epidemiology of E. coli was tested on a group of 524 strains of human and veterinary origin. In the studied group 18 different genotypes were detected. Significant differences were found in the frequencies of the genotypes among various groups of strains, suggesting the method could be a promising tool in the epidemiology of E. coli.

PCR-RFLP detection and species identification of fungal pathogens in patients with febrile neutropenia

OBJECTIVE

To assess the usefulness of polymerase chain reaction (PCR) assays in the diagnosis of fungal infections in immunocompromised patients.

METHODS

A rapid and sensitive PCR-based assay for the detection and identification of fungal pathogens was designed and applicability of this method was investigated in a group of children with cancer and febrile neutropenia (FN).

RESULTS

The ITS2 sequences and adjacent regions of 40 fungal pathogens were analyzed and primers for detection of all analyzed fungal species were designed. Amplification product length polymorphism (APLP) and restriction fragment length polymorphism (RFLP) generated genus- or species-specific patterns. The sensitivity of the method was approximately three cells of Candida albicans per 1 mL of blood. The results were available within 8 h after sample collection. The method was tested on 53 blood samples and one lung biopsy sample from 24 children with cancer and febrile neutropenia (FN). The PCR assay detected fungal DNA in 25 clinical samples from ten patients. Blood cultures were positive in only five samples, while another two blood-culture negative patients had positive cultures from throat swabs. The remaining 14 patients were both culture- and PCR-negative. Culture-isolated strains matched completely those obtained by PCR-APLP-RFLP identification. The identity of fungal species was confirmed by direct sequencing of amplified products.

CONCLUSION

Our results suggest that PCR-APLP-RFLP assays can be useful in the diagnosis of fungal infections in immunocompromised patients.

[Emergency surgical myocardial revascularization by means of a temporary arterial angioplasty]

The authors describe the case of a patient who was admitted for four-hour lasting acute myocardial infarction of the anterior wall with elevations of ST segments on ECG. The finding obtained in selective coronarography revealed an unsuitable condition for coronary intervention (a narrow stenosis of the stem, RIA occlusion, further two narrow stenoses in the coronary vascular bed). Since an operation room was not available at the moment the patient was indicated for palliative PTCA RIA (prevention of necrosis evolution) and subsequent urgent complete surgical revascularization of myocardium. The uncomplicated post-operation course and returned function of the affected myocardium indicates that the intervention may be considered as a suitable alternative for the treatment of acute myocardial infarction.

Staphylococcus aureus isolates from dairy cows and humans on a farm differ in coagulase genotype

Staphylococcus aureus is a frequent cause of animal and human infections. The aim of the present study was to test diversity of the populations of S. aureus colonising cattle and humans sharing an infected environment. Eighty-six S. aureus isolates obtained from dairy cows, from people coming into contact with dairy cows on the farm and the other farm personnel were characterized by restriction fragment length polymorphism of the coagulase gene. Molecular analyses identified ten polymorphism types with prevalent presentation of type II in isolates from cow's milk and type IV in isolates from people coming into contact with dairy cows on the farm (the cattlemen) and the other farm personnel. Seven further genotypes were identified among the isolates from the cattlemen. The results indicate that the strains dominating in human population did not equate to the causative agents of bovine mastitis.

Molecular diagnosis of culture negative infective endocarditis: clinical validation in a group of surgically treated patients

OBJECTIVE

To assess the clinical validity of polymerase chain reaction (PCR) based molecular methods in the microbiological diagnosis of culture negative infective endocarditis in a group of surgically treated patients.

DESIGN

Retrospective case-control study.

SETTING

Reference cardiovascular surgical centre. PATIENTS AND SAMPLES: 15 culture negative patients with infective endocarditis classified according to Duke criteria, with 17 heart valve samples; 13 age and sex matched control patients without infective endocarditis, with 13 valve samples.

INTERVENTIONS

Medical records were reviewed and clinical, demographic, and microbiological data collected, including results of molecular detection of bacteria and fungi from valve samples. The clinical validity of molecular diagnosis was assessed, along with the sensitivity and speed of the systems.

RESULTS

In the study group, 14 patients were PCR positive (93%). Organisms detected were streptococci (3), staphylococci (2), enterobacter (1), Tropheryma whippelii (1), Borrelia burgdorferi (1), Candida albicans (1), and Aspergillus species (2). Three cases were positive on universal bacterial detection but the pathogen could not be identified because of contaminating background. One case was negative. All but two positive cases showed clinical correlations. These two cases had no symptoms of infective endocarditis but there was agreement with the surgical findings. All control cases were PCR negative. Results were available within eight hours, and if sequencing was necessary, within 48 hours.

CONCLUSIONS

PCR based molecular detection of pathogens in valve samples from surgically treated culture negative infective endocarditis patients is fast, sensitive, and reliable. The technology, combined with thorough validation and clinical interpretation, may be a promising tool for routine testing of infective endocarditis.

[Molecular diagnosis of infections]

Molecular diagnostics (detection of nucleic acids by molecular genetics techniques) become more valuable in clinical diagnosis of disease. Apart from the already long-time used genetic techniques for detection of congenital anomalies, current use of molecular techniques includes detection of microbial pathogens. The character of these techniques increases the possibility of achieving diagnosis in cases where classical cultivation is not possible, is not reliable or is not fast enough. As with every new approach, molecular diagnostics have faced encountered reactions from the scientific community. Some scientists tend to overestimate the value of molecular diagnostic techniques, while sceptics, sometimes influenced by a biased or incomplete knowledge of the technology, think it is of little value. In this work, on the basis of literature and our own data from more than 5 years of experience with these methods, we have assessed the pros and cons of the use of molecular diagnostics of infectious diseases in the light of their potential use in clinical practice.

[TT virus infection in liver transplant recipients with cryptogennic cirrhosis]

The possible causative role of novel TT virus in liver diseases has been intensively studied in regarding its hepatotrophy, ability to cause persistent infection and worldwide prevalence. The aim of this study was to estimate the prevalence as well as the clinical importance of TTV in a normal healthy population group in the Czech Republic and in a group of liver transplant recipients diagnosed with cryptogenic cirrhosis. Polymerase chain reaction (PCR) detected the DNA of TT virus in 68% (13/19) of samples isolated from peripheral blood leukocytes and in 21% (4/19) of plasma samples in the liver transplant group. The viral DNA was detected only in 11.8% (4/34) of leukocytes and in no plasma sample from the healthy population control group. All patients included in this study had good liver function and had no complications during the postoperative period. The prevalence of TTV DNA detection in healthy control group in Czech republic is similar to the rates reported in European and North American countries. Significant difference was proved between the prevalences of TTV in the groups of healthy controls and liver transplant recipients with cryptogenic cirrhosis. However, no association of TTV infection with possible postoperative complications could be found.

Pneumopericardial tamponade after coronary artery bypass operation

A case of relatively uncommon post-operative cardiac tamponade caused by air is described.

Pericardial constriction caused by Candida albicans

An uncommon occurrence of constrictive pericarditis caused by Candida albicans and its treatment by successful pericardectomy and epicardectomy are described. For pathogen detection, both cultivation and molecular diagnostics were used. The speed and reliability of molecular diagnostics using polymerase chain reaction make this method a powerful tool for pathogen detection in any clinical specimen.

The relationship among apolipoprotein(a) polymorphisms, the low-density lipoprotein receptor-related protein, and the very low density lipoprotein receptor genes, and plasma lipoprotein(A) concentration in the Czech population

Increased plasma concentration of lipoprotein(a) [Lp(a)] is an established independent risk factor for coronary artery disease (CAD), which is strongly genetically determined. This study was designed to investigate the relationship between the K-IV and (TTTTA)n apolipoprotein(a) [apo(a), protein; APOA, gene] polymorphisms, as well as the C766T low-density lipoprotein receptor-related protein (LRP) and the (CGG)n very low density lipoprotein receptor (VLDLR) polymorphisms on the one hand, and plasma Lp(a) levels in Czech subjects who underwent coronary angiography on the other hand. The lengths of the alleles of the APOA K-IV and (TTTTA)n polymorphisms were strongly inversely correlated with plasma Lp(a) levels in univariate analysis (r = -0.41, p < 10(-4) and r = -0.20, p < 0.01, respectively). Multivariate analysis revealed significant associations between the APOA polymorphisms studied and plasma Lp(a) levels in subjects expressing only one APOA K-IV allele (p < 10(-6) for K-IV and p < 0.001 for TTTTA). In subjects expressing both APOA K-IV alleles, the multivariate analysis revealed that only the APOA K-IV alleles were inversely correlated with plasma Lp(a) levels (p < 0.001). Associations between both the LRP and VLDLR gene polymorphisms and plasma Lp(a) levels were only of borderline significance (p < 0.06 and p < 0.07, respectively) and were not confirmed in multivariate analysis. In conclusion, both APOA length polymorphisms significantly influenced plasma Lp(a) concentration in the Czech population studied, and this circumstance could explain the association in this population observed earlier between APOA (TTTTA)n polymorphism and CAD (Benes et al. 2000). Only a minor role in the regulation of plasma Lp(a) levels is suggested for the C766T LRP and the (CGG)n VLDLR polymorphisms.

The C766T low-density lipoprotein receptor related protein polymorphism and coronary artery disease, plasma lipoproteins, and longevity in the Czech population

Low-density lipoprotein receptor related protein (LRP) is a multifunctional endocytic receptor involved in various biological processes including the regulation of the coagulation-fibrinolysis balance, the lipoprotein metabolism, and cellular migration, all of which relate to the development of atherosclerosis. Polymorphisms affecting the function or expression of LRP may thus influence the individual risk of atherosclerosis development. This study investigated the association between the C766T LRP polymorphism, coronary artery disease (CAD), and plasma lipoprotein levels in a large sample of Caucasian subjects of Czech nationality. In addition, the 4G/5G promoter polymorphism of the gene coding for plasminogen activator inhibitor 1 (PAI-1), the known ligand of LRP with strong antifibrinolytic potential, was ascertained to investigate its possible association with CAD. Both polymorphisms were studied using polymerase chain reaction analysis in 654 patients with angiographically confirmed CAD and in 525 controls. No statistically significant differences in allele frequencies of the polymorphisms studied were detected between patients and controls, even when men, women, hypertonic, and type II diabetic subjects were compared separately. However, the frequency of the T allele of the LRP polymorphism was significantly higher in patients than controls when only subjects with the 5G/5G PAI-1 genotype were analyzed. In addition, the T LRP allele frequency was significantly lower in subjects aged 60 years or over than in those who were younger in both groups. No significant association was observed between the LRP or PAI-1 polymorphisms and plasma lipoprotein levels in the CAD patients. Our results demonstrate that the T allele of the C766T LRP polymorphism is negatively related to longevity, and that it increases the risk of CAD development in subjects with the 5G/5G PAI-1 genotype.

Determination of esmolol in serum by capillary zone electrophoresis and its monitoring in course of heart surgery

A new Capillary Zone Electrophoresis (CZE) procedure for determination of esmolol, an ultra-short-acting beta-blocker, in serum was developed. Dichloromethane was applied as a deproteination agent and it was used also for the inactivation of erythrocytal esterase and in the same time for the extraction of esmolol from blood. The re-extraction of esmolol from organic phase to water phase was performed by 0.01 M HCl. An aliquot of 200 ml of acid aqueous phase was used for the injection and analysis. CZE determination was done in 50 mM phosphate buffer (pH=8.0) with detection at 222 nm. The concentration detection limit of esmolol in serum was 0.051 microg/ml. This method was applied in an extensive heart surgery experiment on pigs (Sus scrofa).

Methylenetetrahydrofolate reductase polymorphism, type II diabetes mellitus, coronary artery disease, and essential hypertension in the Czech population

Increased plasma concentrations of homocysteine have been found in patients with coronary artery disease (CAD) and essential hypertension (EH) and in patients with diabetic complications. The 677C/T methylenetetrahydrofolate reductase (MTHFR) gene polymorphism is related to the MTHFR enzyme activity and to the plasma homocysteine concentration. This study was designed to investigate an association of this polymorphism with CAD, EH, and type II diabetes mellitus in the Czech population. The MTHFR genotypes were assessed by the polymerase chain reaction-based methodology in a sample of 1199 unrelated Caucasian subjects with CAD, EH, type II diabetes, or a combination of these diseases, and in healthy subjects. Allele frequencies of the MTHFR polymorphism differed considerably between women with and without type II diabetes mellitus (P = 0.00069), with a higher frequency of the C allele in the diabetic women. In addition, the MTHFR T allele frequency was significantly higher in normotensive subjects with CAD compared with normotensive subjects without this disease (P = 0.020). Both associations were confirmed by multiple logistic regressions. In conclusion, while the C allele of the 677C/T MTHFR polymorphism is associated with type II diabetes mellitus in women, the T allele is associated with CAD only in normotensive subjects of Czech origin.

The possible role of human cytomegalovirus (HCMV) in the origin of atherosclerosis

BACKGROUND

The biological properties of some herpesviruses such as the ability of latent persistency in the host cells and the presence of viral DNA in atherosclerotic lesions, suggest the possible role of herpesviruses in the development of atherosclerosis. Although many authors proved the presence of viral DNA in arterial wall tissue, the role of herpesviruses in the origin and progress of atherogenesis still remains unclear.

OBJECTIVES

The aim of this study was to confirm the presence of viral DNA in arterial wall and to associate the presence of these viruses with the development of atherosclerosis in patients with ischemic heart disease (IHD).

STUDY DESIGN

A possible role of HCMV, EBV and HHV6 in the development of atherosclerosis was tested in 244 IHD patients and 87 coronarographically negative controls. The presence of viral DNA in aortic and venous walls, as well as in a peripheral blood samples was tested by the use of polymerase chain reaction (PCR) accompanied by, immunological tests for anti-virus antibodies IgM and IgG types for all experimental groups.

RESULTS

The genomic DNA of HCMV was found in 76 and 59%, DNA of EBV in 59 and 50%, and DNA of HHV6 in 0.08 and 0.0%, of arterial walls of IHD patients and non-ischemic control group, respectively. No viral DNA was found in venous samples. Significant association (P < 0.01) has been proved between CMV infection and IHD.

CONCLUSIONS

Our results suggest that HCMV and EBV can be found in the arterial wall, so that the arterial wall could be a potential site of persistency of those viruses. We also proved a significant association between the presence of HCMV DNA in aortic walls and atherosclerosis. Despite of the high genetic and biological similarity between CMV and HHV6 no substantial role of HHV6 in atherosclerosis has been proved.

Single effects of apolipoprotein B, (a), and E polymorphisms and interaction between plasminogen activator inhibitor-1 and apolipoprotein(a) genotypes and the risk of coronary artery disease in Czech male caucasians

To evaluate whether polymorphisms in genes whose products are involved in lipid metabolism and fibrinolysis alter the risk of coronary artery disease (CAD), allele frequencies of four genetic polymorphisms were ascertained by PCR-based methods in 175 Czech male patients with coronary artery disease and in 222 Czech men with no symptoms of CAD. The following polymorphisms were studied: apolipoprotein B (apo B) signal peptide insertion/deletion polymorphism, 5' apolipoprotein(a) [apo(a)] TTTTA repeat polymorphism, apolipoprotein E (apo E) varepsilon2, varepsilon3, varepsilon4 polymorphism, and plasminogen activator inhibitor-1 (PAI-1) 4G/5G promoter polymorphism. Apo B and apo(a) allele frequencies differed significantly between the CAD and the control groups (P<0.01 each), with higher frequencies of apo B deletion and apo(a) shorter repeat alleles in the CAD group. We did not observe any differences in allele frequencies of either PAI-1 or apo E polymorphisms but the genotype frequencies of apo E were slightly different between the two groups (P<0.05). In addition, we observed a gene-gene interaction between the PAI-1 and apo(a) polymorphisms with respect to the risk of CAD. None of the polymorphisms studied were associated with the severity of CAD or a history of myocardial infarction. Our findings support the idea that several polymorphisms in apolipoprotein genes may by themselves and/or in interaction with other polymorphisms contribute to risk factors for CAD in men.

Human herpesvirus-6 infection in children with cancer

Pediatric cancer patients treated with multimodal therapy are at a great risk of opportunistic infections or reactivation of latent infections. Human herpesvirus-6 (HHV-6) can serve as an example of such infection, with high seroprevalence in population. In 66 children with cancer and in 45 healthy controls, age matched, the presence of DNA HHV-6 was examined in peripheral blood by the polymerase chain reaction method. HHV-6 serology was also performed. No difference has been found between patients at the time of cancer diagnosis and the group of healthy children in the presence of DNA HHV-6 in blood, 17.4 and 15.6%, respectively. During cytotoxic chemotherapy the presence of HHV-6 in peripheral blood raised to 37.1% in patients with fever. Other parameters and symptoms such as febrile neutropenia, lymphopenia, exanthem, hepatopathy, lymphadenopathy, enteritis, bone marrow aplasia, pneumonitis, and encephalitis were examined in both the HHV-6 positive and HHV-6 negative groups of pediatric cancer patients. Statistically significant differences (p < .05) were found in case of lymphopenia, exanthem, and hepatopathy. In 4 out of 66 patients (6.1%) severe HHV-6 infection has been found: in 3 patients during cytotoxic chemotherapy and in 1 at the time of cancer diagnosis. Reactivation of HHV-6 infection in pediatric cancer patients under treatment with cytotoxic chemotherapy is frequent and can lead to severe complications as described in patients after bone marrow or organ transplantation.

[Polymerase chain reaction in diagnosis of infection of total knee replacement.]

Polymerase chain reaction allows a direct detection of DNA of bacterial pathogens in synovial fluid. With the help of artificially synthetized nucleotides, the so called primers, and in the presence of DNA polymerase enzyme it is possible to produce a great number of copies of the DNA being investigated and subsequently detect them. Authors used this method in 32 symptomatic knees after TKR (P.F.C. cemented type - Johnson and Johnson). Group I (pyogenic infection) comprised 14 patients. Their clinical condition required operation - extraction of TKR, debridement, spacer, lavage. All of them were PCR positive. Only 6 patients had a positive bacteriological cultivation, 8 of them were bacteriologically negative. Group II (synovialitis) included 18 patients. All of them had a negative bacteriological cultivation. Group II.a showed a slightly positive PCR reaction (mitigated infection, detection of DNA microbes incapable of reproduction). After the treatment by antibiotics the patients were without complaints. Group IIb included patients who were all PCR negative. Their case was non-bacterial irritation of synovial membrane. They had a good response to non-steroid antiflogistics. The sensitivity of PCR method is 100%, it can detect also microbes in patients treated by antibiotics. PCR method is fast providing results within 24 hours. It reliably detects the presence of bacteria in the punctate, it specifies diagnosis and contributes to the distinguishing between pyogenic infection from non-bacterial synovialitis. Key words: total knee replacement, infection.

[Use of genetic methods in the detection of pathogens in complications of extensive surgical procedures]

The method of the polymerase chain reaction (PCR) is used in the detection of septic conditions and monitoring of infectious agents in asymptomatic patients after organ transplantations and extensive cardiosurgical operations. The method allows semiquantitative and quantitative detection of bacteria, micromycetes and viruses and from the systematic quantitative follow-up of pathogen levels it is possible to draw conclusions on the prognosis of the patients condition or the success of the therapeutic procedure. The author demonstrates on practical examples of examined patients the possibilities of the method as compared with hitherto used ones. As examples two patients are quoted after surgery of a valve on account of bacterial endocarditis and three patients after transplantation of life important organs where the presence if cytomegalovirus was detected.

Drosophila melanogaster, Vicia faba and Arabidopsis thaliana short-term bioassays in genotoxicity evaluation of air and soil samples from sites surrounding two industrial factories in the Czech Republic

The Somatic Mutation and Recombination Test (SMART) in wing cells of Drosophila melanogaster, the Vicia faba cytogenetic tests-Sister Chromatid Exchange (SCE) and Micronucleus Test (MN), and the Müller test for gametic mutations in Arabidopsis thaliana were used for genotoxicity testing of environmental samples of pollutants from the surroundings of LACHEMA chemical factory (Brno, Czech Republic) and DEZA factory in Valasské Mezirící (Moravia, Czech Republic). Tested soil and air samples were taken from the near vicinity of both factories. The surroundings of both sites are heavy loaded by exhalation of chemicals from the factories. Chemical analyses of the 16 Polycyclic Aromatic Hydrocarbons (PAHs) according to the United States Environmental Protection Agency (US EPA) list of priority pollutants and heavy metals were performed in both soil and air samples. The Drosophila wing spot test was positive in 70.6% of the tested samples, the Vicia sister chromatid exchange test in 62.5%, and the Arabidopsis Müller test in 58.9%. The micronucleus Vicia faba test was quite insensitive in tested environmental samples. The concordance between SMART and SCE was 62.5%, between SMART and Müller test 76.5%, and between Müller test and SCE 100%. Total concordance of these three tests was 79.7%. Müller test for gametic mutation in Arabidopsis thaliana and cytogenetic SCE test in Vicia faba seem to be quite sensitive and convenient plant bioassays for assessing the mutagenic potential of environmental agents, when compared to the SMART test in Drosophila melanogaster.

Genotoxicity of N-nitroso-N-methylurea and acetone oxime in the transgenic Drosophila carrying the human gene encoding a subunit of glutathione S-transferase

The genotoxic effects of N-nitroso-N-methylurea (MNU) and acetone oxime (ACOX) were tested in the Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster. We have performed the same assay on transgenic flies expressing the human gene encoding a glutathione S-transferase alpha subunit (HGST). The SMART assay is used here to demonstrate genotoxicity and to determine the effect of human glutathione S-transferase on the genotoxic response. Three types of Drosophila strains were used: non-transgenic strains first described by Szabad (1986), transgenic strains derived from the Szabad strains but expressing the bacterial lacZ gene, and similarly derived transgenic strains expressing the HGST gene. MNU was highly genotoxic in both transgenic and non-transgenic flies. The non-transgenic lies were significantly more sensitive to the genotoxic effects of MNU compared to both types of transgenic flies. There were statistically significant differences between the transgenic HGST crosses and transgenic lacZ and non-transgenic control crosses but there was no significant difference between the genotoxic response to MNU in flies from the transgenic cross with lacZ and from the cross carrying three copies of HGST. ACOX also proved to be genotoxic to both non-transgenic and transgenic flies. However, flies carrying three copies of the gene were significantly more resistant to the genotoxic effect of ACOX than those transgenic flies with two or no copies of the human gene.