Biomedical subjects

G Dettori

Publications and source records attributed to G Dettori.

At least 19 recordsLinked to original sources

PubMed2006

Comparative evaluation of molecular assays for the identification of intestinal spirochaetes from diseased pigs.

Rapid identification of porcine Brachyspira species is required in order to differentiate pathogenic from non-pathogenic species. The aim of our study was to compare a recently described genetic method based on polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP), nox RFLP-PCR assay, and three species-specific PCRs described previously in the literature with a 16S rRNA gene RFLP-PCR discriminatory reference assay (16S RFLP-PCR) for the identification of Brachyspira spp. of swine origin. In this study, 20 porcine spirochaetal strains were identified and compared to 33 reference strains by 16S RFLP-PCR and nox RFLP-PCR and three species-specific PCRs. RFLP-PCR methods showed concordant results for 47 strains and discordances for 6 strains (2 differently identified and 4 not revealed by nox RFLP-PCR). In our hands species-specific PCRs showed concordant results with 16S and nox RFLP-PCR for 43 strains and discordances for 10 strains (2 differently identified and 8 not amplified). The same results observed testing the 20 field-isolated spirochaetes were obtained for the corresponding porcine faecal samples. The detection limit was 10(2) -10(3) cells/g of faeces for 16S rRNA gene PCR and 10(4) cells/g of faeces for nox PCR. In our experience nox RFLP-PCR appeared successful for the speciation of B. hyodysenteriae reserving 16S RFLP-PCR for all other pathogenic and non-pathogenic Brachyspira species. Among the species-specific PCR assays tested only that for B. pilosicoli was useful in our hands.

Animals↗

PubMed2004

Rapid isolation of Brachyspira hyodysenteriae and Brachyspira pilosicoli from pigs.

The aim of this study was to compare and evaluate the time required to isolate Brachyspira hyodysenteriae and Brachyspira pilosicoli from porcine faeces. This was done using previously described selective media (spectinomycin) S400, (colistin, vancomycin and spectinomycin) CVS and (spectinomycin, vancomycin, colistin, spiramycin and rifampin with swine faecal extract) BJ, compared with the method based on blood agar modified medium, with spectinomycin and rifampin (BAM-SR), including a pre-treatment step. Fourteen spirochaetal strains were obtained in pure cultures after 5 days (48 h in BAM-SR primary plate and three passages every 24 h in brain heart infusion (BHI) without antibiotics) pre-treating simulated samples in brain heart infusion broth with spectinomycin (400 microg/ml) and rifampin (15 microg/ml), before streaking on the selective BAM-SR medium. Spirochaetes from samples in S400, CVS and BJ, with and without pre-treatment, were obtained in pure cultures only after repeatedly transferring on plates of the same selective medium requiring 15-18 days according to the strain. BAM-SR used after the pre-treatment step showed a detection limit ranging from 3.5 x 10(2) to 6.7 x 10(7) cells/g faeces and was the only method able to support the growth of spirochaetes after 48 h.

Animals↗

PubMed2004

The mesenteric and antimesenteric location of colorectal cancer: the relationship with lymph nodes.

AIM: Purpose of the study was to evaluate if the circumferential location of colorectal cancer may be identified as a possible prognostic factor. The hypothesis is that tumours located on the antimesenteric (AM) side could have a better prognosis than tumours located on the mesenteric (M) side. METHODS: All patients undergoing curative resection for colorectal cancer were enrolled in the study. The specimens were sent to the pathologist to define the exact location of the tumour, the histological type, grading, T, N status as well as lymphatic, vascular and neural invasion, peritumoural lymphoid reaction, desmoplasia and microsatellite instability. Statistical analyses were performed using the test for proportions (with continuity correction), the Pearson Chi-square test and generalised linear models; p<0.05 were considered statistically significant. RESULTS: From August 2000 to August 2002, 255 patients were enrolled in the study. There was a significantly higher incidence of tumours located on the M (101) compared with the AM (37) site (p<0.0001). M located tumours were associated with higher numbers of metastatic lymph nodes (N1 and N2; p-value=0.014), whereas AM tumours were associated with involved lymph nodes in only 5/37 (13.5%) of tumours. There was no statistically significant relation between AM versus M location and T status: the Pearson Chi-Square test showed that the lymph node involvement and the location (M versus AM) are not statistically independent variables (p-value=0.014). CONCLUSIONS: Our preliminary results show that when M or AM tumour identification is possible, tumour location can be regarded as a prognostic factor. Further longer studies on recurrence rate and survival are required to validate these findings and the clinical usefulness of this putative prognostic factor.

Adult↗

PubMed2004

Development of a real-time PCR assay for detection of Plasmodium falciparum, Plasmodium vivax, and Plasmodium ovale for routine clinical diagnosis.

A TaqMan-based real-time PCR qualitative assay for the detection of three species of malaria parasites-Plasmodium falciparum, P. ovale, and P. vivax-was devised and evaluated using 122 whole-blood samples from patients who had traveled to areas where malaria is endemic and who presented with malaria-like symptoms and fever. The assay was compared to conventional microscopy and to an established nested-PCR assay. The specificity of the new assay was confirmed by sequencing the PCR products from all the positive samples and by the lack of cross-reactivity with Toxoplasma gondii and Leishmania infantum DNA. Real-time PCR assay showed a detection limit (analytical sensitivity) of 0.7, 4, and 1.5 parasites/ micro l for P. falciparum, P. vivax, and P. ovale, respectively. Real-time PCR, like nested PCR, brought to light errors in the species identification by microscopic examination and revealed the presence of mixed infections (P. falciparum plus P. ovale). Real-time PCR can yield results within 2 h, does not require post-PCR processing, reduces sample handling, and minimizes the risks of contamination. The assay can therefore be easily implemented in routine diagnostic malaria tests. Future studies are warranted to investigate the clinical value of this technique.

Animals↗

PubMed2004

Evaluation of a new plate hybridization assay for the laboratory diagnosis of imported malaria in Italy.

A new molecular diagnostic method "Malaria-IBRIDOGEN" (Amplimedical S.p.A.--Bioline Division, Turin, Italy) based on a plate-hybridization assay for the simultaneous detection and identification of human malaria parasites was evaluated in this study. A target DNA sequence of the plasmodial 18S ribosomal RNA gene was amplified by polymerase chain reaction (PCR) and hybridized in microtiter wells with five biotinylated probes each specific for Plasmodium falciparum, P. vivax, P. malariae, P. ovale and the beta-globine human gene, respectively. Compared to the nested-PCR actually used in our laboratory for the molecular diagnosis of malaria, "Malaria-IBRIDOGEN" revealed an overall sensitivity of 100% (51/51) for the four human Plasmodium species testing 100 whole blood samples from people with malaria-like symptoms and fever. Specificity was 92% (45/49) considering four discordant samples as "false positive" by "Malaria-IBRIDOGEN". The assay showed a threshold of parasite density (detection limit) of 0.07 P. falciparum parasites/microliter, 0.15-1.5 P. vivax parasites/microliter, 0.3 P. malariae parasites/microliter and 0.4 P. ovale parasites/microliter of whole blood, respectively. This assay could be successfully applied to the laboratory diagnosis of malaria as a useful aid to microscopy.

Animals↗

PubMed2003

Human cytomegalovirus proteins PP65 and IEP72 are targeted to distinct compartments in nuclei and nuclear matrices of infected human embryo fibroblasts.

The cellular distribution of the human cytomegalovirus (HCMV)-specific UL83 phosphoprotein (pp65) and UL123 immediate-early protein (IEp72) in lytically infected human embryo fibroblasts was studied by means of indirect immunofluorescence and confocal microscopy. Both proteins were found to have a nuclear localization, but they were concentrated in different compartments within the nuclei. The pp65 was located predominantly in the nucleoli; this was already evident with the parental viral protein, which was targeted to the above nuclear compartment very soon after infection. The nucleolar localization of pp65 was also observed at later stages of the HCMV infectious cycle. After chromatin extraction (in the so-called in situ nuclear matrices), a significant portion of the pp65 remained associated with nucleoli within the first hour after infection, then gradually redistributed in a perinucleolar area, as well as throughout the nucleus, with a granular pattern. A quite different distribution was observed for IEp72 at very early stages after infection of human embryo fibroblasts with HCMV; indeed, this viral protein was found in bright foci, clearly observable in both non-extracted nuclei and in nuclear matrices. At later stages of infection, IEp72 became almost homogeneously distributed within the whole nucleus, while the foci increased in size and were more evenly spread; in several infected cells some of them lay within nucleoli. This peculiar nuclear distribution of IEp72 was preserved in nuclear matrices as well. The entire set of data is discussed in terms of the necessity of integration for HCMV-specific products into the pre-existing nuclear architecture, with the possibility of subsequent adaptation of nuclear compartments to fit the needs of the HCMV replicative cycle.

Cell Fractionation↗

PubMed2003

Identification of Plasmodium falciparum, P. vivax, P. ovale and P. malariae and detection of mixed infection in patients with imported malaria in Italy.

The species-specific nested-PCR previously described by Snounou and others for detecting the four parasite species that cause human malaria is evaluated in the current study testing 230 blood samples. The results are compared with those obtained by microscopy and, for 101 samples out of 230, with those previously obtained by a genus-specific PCR based method (pg-PCR) followed by species-specific Southern-blot hybridization. All blood specimens were obtained from patients (127 foreigners and 103 Italians) with a suspect clinical diagnosis of imported malaria in Italy: 76 were positive by microscopy and 83 were positive by nested-PCR. The last method also revealed 10 double infections (8 foreigners and 2 Italians) which were not identified by microscopy or by pg-PCR with species-specific Southern-blot hybridization. Fifty-four out of 83 positive samples tested by nested-PCR were submitted to genomic sequence analysis, which confirmed the presence of DNA region portion encoding the 18S rRNA corresponding to the Plasmodium species identified by nested-PCR. These results demonstrate that the nested-PCR assay surpasses microscopy and pg-PCR with species-specific Southern-blot hybridization, both in sensitivity and in diagnostic accuracy. Moreover, it is quicker because it requires no further blotting or hybridization of PCR amplification products. This method also offers a clear advantage in the detection of mixed infections, which is important not only for successful medical treatment but also for the study of malaria epidemiology. Finally, our study also highlights the value of genomic sequence analysis for validating PCR results.

Animals↗

PubMed2003

Evaluation of susceptibility of Mycobacterium bovis to antituberculous drugs by radiometric BACTEC 460TB system.

Susceptibility of Mycobacterium bovis strains to antituberculous drugs (isoniazid and rifampin) was detected by radiometric BACTEC 460TB system. M.bovis strains were isolated from tissue samples showing tuberculous lesions collected at an abbattoir from cattle belonging to 47 tuberculosis outbreaks occurring in Northern Italy in 1995-1999. Forty-six out of 61 strains (75.4%) resulted susceptible to both isoniazid and rifampin. Thirteen strains (21.3%) were resistant to isoniazid only. No strains showed resistance to rifampin only. Two strains (3.3%) resulted resistant to both drugs, showing antituberculous multidrug-resistance. Given the compulsory eradication program of bovine tuberculosis by elimination of infected animals and the ban on antituberculous drug treatments in animals, detection of resistant M. bovis strains appears of great interest.

Animals↗

PubMed2003

The role of (99m)Tc-tetrofosmin pinhole-SPECT in breast cancer non palpable axillary lymph node metastases detection.

AIM: We evaluated the usefulness of (99m)Tc-tetrofosmin axillary pinhole (P)-SPECT in breast cancer (BC) non palpable axillary lymph node metastasis detection compared with conventional planar and SPECT scintimammography. METHODS: We studied prospectively 188 consecutive patients with suspected primary BC, negative at axillary clinical examination. Ten minutes after 740 MBq (99m)Tc-tetrofosmin injection, planar and SPECT scintimammography were acquired, followed by axillary P-SPECT imaging. RESULTS: At histology, 12 patients had benign mammary lesions and 176 had BC. Axillary lymph node dissection (ALND) was performed in all BC patients, bilaterally in 3 cases: 74/179 axillae had metastases. P-SPECT showed a significantly higher overall sensitivity than SPECT and planar (93.2% vs 85.1% and 36.5%, respectively; p<0.05 and p<0.0005, respectively) and was false negative in 5 patients with 1 metastatic node each, micrometastatic in 4/5 cases; SPECT and planar were also false negative in these 5 cases and in 6 and in 42 further cases, respectively. P-SPECT added important prognostic information by distinguishing single from multiple and pound 3 from >3 nodes; only P-SPECT defined the exact number of nodes in 15/25 patients with 2-4 nodes. P-SPECT showed the highest accuracy and NPV: 92.7% and 95%, respectively (SPECT 90.5% and 90%, respectively; planar 73.2% and 68.9%, respectively). CONCLUSION: (99m)Tc-tetrofosmin axillary P-SPECT appears highly accurate in BC non palpable axillary lymph node metastasis detection and significantly more sensitive than both planar and SPECT, its few false negative results predominantly concerning micrometastases; moreover, only P-SPECT gave additional important prognostic information. Given its very high NPV, P-SPECT could also be used to better select patients who might avoid ALND.

Adult↗

PubMed2002

Percutaneous vacuum-assisted core breast biopsy with upright stereotactic equipment. Indications, limitations and results.

PURPOSE: To assess the usefulness of stereotactic vacuum-assisted core breast biopsy (VCBB) performed using a stereotactic add-on device and film-screen technology with the patient in an upright seated position. MATERIAL AND METHODS: We reviewed a series of 129 women with non-palpable mammographic abnormalities who required stereotactic VCBB from December 1999 to November 2000. Twenty-seven (20.9%) cases were excluded due to difficulties in keeping the correct position during the procedure, while the other 102 (79.1%) underwent successful VCBB. Patients with lesions consisting of either atypical ductal hyperplasia or lobular carcinoma in situ were considered for excisional biopsy. Patients with either ductal carcinoma in situ or infiltrating breast cancer were referred for definitive surgery. The results of stereotactic VCBB were correlated to the subsequent surgical histology. RESULTS: Stereotactic VCBB was interrupted because of bleeding in 1 case and vasovagal reaction in 5 cases. Two haematomas occurred after the procedure. Overall underestimation rate was 10.5%. No new lesions were discovered after a mean follow-up of 18.7 months. CONCLUSION: Stereotactic VCBB performed using a standard add-on device with the patient in an upright seated position and analog technology is feasible in about 80% of cases, has a low complication rate, is not significantly time-consuming, and can offer the same accuracy as dedicated prone equipment.

Biopsy, Needle↗

PubMed2002

Brachyspira (Serpulina) pilosicoli of human origin interfere with the growth of Clostridium perfringens alpha-toxin producer.

Brachyspira (Serpulina) pilosicoli of human origin interfere with the growth of Clostridium perfringens alpha-toxin producer reducing the clostridial growth area and colonies number when bacteria were cultivated together in sheep blood agar plates. The growth inhibition of C. perfringens was only observed when B. (S.) pilosicoli grew 72-96 hours sooner than C. perfringens and after the inoculum of this latter the plates were anaerobically incubated for additional 48 hours. The phenomenon was observed at concentrations of B. (S.) pilosicoli ranging from 10(7) to 10(4) CFU/ml and at concentrations of C. perfringens ranging from 10(7) to 10(1) CFU/ml when the bacteria were 0-10 mm away from each other. When B. (S.) pilosicoli and C. perfringens were inoculated at the same time and when B. (S.) pilosicoli grew 24-48 hours sooner than C. perfringens, the clostridial growth inhibition was not appreciated and only a cooperative haemolysis was observed between the bacteria.

Antibiosis↗

PubMed2002

Brachyspira (Serpulina) pilosicoli of human origin interfere with the haemolytic activity and the growth of Staphylococcus aureus beta-toxin producer.

Brachyspira (Serpulina) pilosicoli related to intestinal spirochaetosis were found to interfere in vitro with the haemolytic activity and the growth of Staphylococcus aureus beta-toxin producer. This interference was clearly appreciated because a reduction of the zone of the staphylococcal beta-toxin activity, the reduction and/or absence of cooperative haemolysis between bacteria, and the growth reduction of S. aureus were observed when B. (S.) pilosicoli were grown 72-96 hours sooner than S. aureus and after the inoculum of the latter the plates were anaerobically incubated for additional 48-72 hours. The phenomenon was more clearly observed when B. (S.) pilosicoli had a concentration of 8x10(6)-8x10(7) CFU/ml and S. aureus at a concentration ranging from 10(7) to 10(1) CFU/ml was inoculated at a distance from the streaks of B. (S.) pilosicoli ranging from 0-10 mm. When B. (S.) pilosicoli and S. aureus were inoculated at the same time and when B. (S.) pilosicoli grew 24-48 hours sooner than S. aureus only a cooperative haemolysis was observed.

Antibiosis↗

PubMed2001

(99)mTc-tetrofosmin SPET in the detection of both primary breast cancer and axillary lymph node metastasis.

The aim of this study was to evaluate the usefulness of (99m)Tc-tetrofosmin single-photon emission tomography (SPET) in the detection of both primary breast cancer and axillary lymph node metastasis. We studied 192 consecutive patients in whom primary breast cancer was suspected on the basis of mammography and/or physical examination. After intravenous injection of 740 MBq (99m)Tc-tetrofosmin, both planar and SPET scintimammography was performed in all patients using a rectangular dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators. In 175 patients with breast cancer at histology, the per-lesion overall sensitivity of SPET and planar imaging for the detection of breast cancer was 95.8% and 75.9% (P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 96.5% and 79.5% in palpable (P<0.0005) and 90% and 45% in non-palpable lesions (P<0.01). With regard to lesion size, the sensitivity of SPET and planar imaging was, respectively, 90.5% and 45.2% in lesions < or =10 mm ( P<0.0005), 95.3% and 81.4% in lesions of 11-20 mm (P<0.005), 100% and 84.6% in lesions of 21-30 mm (P<0.05) and 100% and 95.8% in lesions >30 mm (P>0.05). In the remaining 17 patients with benign mammary lesions at histology, per-lesion overall specificity of SPET and planar imaging was 76.2% and 85.7% (P>0.05), respectively. Neither SPET nor planar imaging showed false-positive results in non-palpable lesions or in those < or =10 mm. In 173 breast cancer patients submitted to axillary lymph node dissection (ALND), per-axilla overall sensitivity of SPET and planar imaging in the detection of axillary lymph node metastasis was 93% and 52.3% ( P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 100% and 82.6% in palpable nodes (P>0.05), 90.5% and 41.3% in non-palpable nodes (P<0.0005), 92.8% and 35.7% in the presence of < or =3 nodes ( P<0.0005) and 93.2% and 68.2% in the presence of >3 nodes (P<0.005). The specificity of SPET and planar imaging was 91% and 100% (P<0.05), respectively. (99m)Tc-tetrofosmin SPET appears to be a reliable method for the detection of both primary BC and axillary lymph node metastasis, and its diagnostic accuracy exceeds that of (99m)Tc-tetrofosmin planar scintimammography. The use of SPET is particularly important in the identification of small non-palpable primary carcinomas and metastatic axillae with < or =3 non-palpable lymph nodes. More extensive use of SPET appears warranted in the management of breast cancer patients.

Axilla↗

PubMed2001

A novel method for isolation of Brachyspira (Serpulina) hyodysenteriae from pigs with swine dysentery in Italy.

Brachyspira (Serpulina) hyodysenteriae was isolated from 10 of 11 pigs with clinically suspected swine dysentery in six herds in northern Italy. All strains were successfully isolated in the selective blood agar modified medium with spectinomycin and rifampin (BAM-SR) currently used in our laboratory to isolate B. (S.) pilosicoli of human origin, after pre-treatment of intestinal material with spectinomycin and rifampin in foetal calf serum. Isolates had phenotypic characteristics typical of B. (S.) hyodysenteriae.

Animals↗

PubMed2001

Genomic instability in chronic viral hepatitis and hepatocellular carcinoma.

Chronic hepatitis may progress to cirrhosis and hepatocellular carcinoma (HCC). Progressive accumulation of mutations and genomic instability in chronic viral hepatitis might flag an increased risk of HCC development. Genomic instability at dinucleotide microsatellite loci in chromosomes 2, 13, and 17 and at 2 mononucleotide repeat loci was examined in liver tissues from 41 patients, including 30 without HCC (18 patients with chronic hepatitis and 12 with cirrhosis) and 11 with HCC. Genomic instability was detected in 51% of the 41 cases. Allelic imbalance at informative dinucleotide loci occurred in 37% of the cases. In 14 cases (34%), allelic imbalance was detected in chronic hepatitis or cirrhosis without HCC. Allelic imbalance at the chromosome 13 locus was detected in 50% of the cases of chronic hepatitis C. Allelic imbalance at the TP53 chromosome locus and/or at the chromosome 13 locus was significantly more frequent than alterations at the chromosome 2 locus (P =.026). Low-level microsatellite instability was found in 20% of all cases examined and high-level microsatellite instability in 3 patients (7.5%), including 2 cases of chronic hepatitis and 1 case of cirrhosis. Our results show that allelic imbalance occurs frequently in hepatitis-related HCC as well as in chronic hepatitis in patients without HCC. Allelic imbalance at the D13S170 chromosome 13 locus (13q31.2) occurs frequently in chronic hepatitis, suggesting that genomic alterations affecting the long arm of chromosome 13 might be used to monitor the natural progression of chronic hepatitis-associated liver carcinogenesis.

Adult↗

PubMed2001

99mTc-Tetrofosmin pinhole-SPECT (P-SPECT) and radioguided sentinel node (SN) biopsy and in breast cancer axillary lymph node staging.

We compared 99mTc-Tetrofosmin P-SPECT with radioguided SN biopsy in 101 T1/T2 BC pts to predict axillary lymph node status. The day before surgery all pts underwent lymphoscintigraphy (LS) to mark the SN, following subdermal injection of 99mTc-colloidal sulphur surrounding the breast lesion. LS was combined with pre and intraoperative gamma probe. Previously, all pts had also undergone P-SPECT. ALND was performed in all cases. The SN(s) was detected in 97/101 cases (96%) by LS and gamma probe; in the 4 missed cases P-SPECT predicted lymph node status. In the 97 comparable cases, radioguided SN biopsy showed a slightly higher accuracy than P-SPECT (94.8% vs 93.8%), but a higher false-negative rate (14.3% vs 8.6%); P-SPECT had a higher NPV (95.2% vs 92.5%). The two procedures when combined achieved 100% accuracy. Radioguided SN biopsy alone had 100% accuracy only in pts with BC < 15 mm. P-SPECT had 3 false negative cases, 2 of which were micrometastatic SNs, and 3 false positives. P-SPECT identified 81.2% of cases with a single node, determined the exact number of nodes in 82.6% of cases with 1 to 3 node and correctly classified 93.7% of pts as having < or = 3 or > 3 metastatic nodes. Radioguided SN biopsy seems indicated in selected, early stage, small BC pts, while P-SPECT shows a high sensitivity independent of primary tumor size, giving additional important preoperative prognostic information. The two procedures combined provided a better axillary lymph node status prediction in T1/T2 carcinomas, and could thus improve ALND pt selection.

Adult↗

PubMed2001

Usefulness of genus-specific PCR and Southern blot species-specific hybridization for the detection of imported malaria cases in Italy.

A PCR method involving a genus-specific oligonucleotides set and Southern blot hybridization with four species-specific probes to P. falciparum, P. vivax, P. malariae and P. ovale was evaluated for the detection of malaria parasites in blood samples from 101 patients with clinically suspect malaria infection imported to Italy. Plasmodium falciparum was the main species detected. As determined by microscopy, 53 (52.4%) patients had malaria and of these: 40 (75.5%) were infected with P. falciparum; 7 (13.2%) with P. vivax; 1 (1.9%) with P. ovale; 3 (5.7%) with P. malariae; 1 (1.9%) with P. vivax or P. ovale; and 1 (1.9%) with P. falciparum or P. vivax. Ninety-seven out 101 blood samples were submitted to ParaSight-F test which showed a sensitivity of 94.73%, and a specificity of 93.22%, as compared to microscopy. The PCR assay using the genus-specific oligonucleotide primer set (pg-PCR) was able to detect 53 (52.4%) infections and showed a sensitivity of 100% and a specificity of 100%, when compared to microscopy. The parasite species were identified by Southern blot hybridization using species-specific probes and 40 (75.5%) samples were P. falciparum positive, 5 (9.4%) P. vivax positive, 4 (7.5%) P. ovale positive, and 2 (3.8%) P. malariae positive. When the Southern blot results were compared to those of blood-film diagnosis, we observed some disagreement. In particular, compared to Southern blot, microscopy underestimated P. ovale infection; blood film analysis recognised only 1 P. ovale sample, whereas Southern blot recognised 4 P. ovale positive samples (by microscopy, 2 of these were detected as P. vivax, 1 as P. ovale or P. vivax, and the other as P. falciparum or P. vivax). Southern blot hybridization was unable to identify one P. falciparum and one P. vivax positive case detected by microscopy. We also plan to use a reference nested-PCR assay to clarify the disagreement observed between microscopy and Southern blot hybridization.

Animals↗

PubMed2001

Weakly beta-haemolytic human intestinal spirochaetes antagonize the haemolytic activity of Clostridium perfringens alpha-toxin producer.

The production of haemolytic antagonism between weakly beta-haemolytic human intestinal spirochaetes (wbetaHIS) related to human intestinal spirochaetosis and Clostridium perfringens alpha-toxin producer was investigated. A reduction of the clostridial haemolytic activity and a distortion of the haemolytic halo of clostridial alpha-toxin surrounded by a small zone of poorly cooperative haemolysis was clearly observed on the level of the spirochaetal growth area when 40 out of 41 wbetaHIS were cultivated in sheep blood agar plates together with Clostridium perfringens alpha-toxin producer. This phenomenon of haemolytic antagonism was observed only when wbetaHIS grew 72-96 hours sooner than C. perfringens and after the inoculum of the latter at a distance of 0 to 10 mm from wbetaHIS the plates were anaerobically incubated for an additional 48 hours and the bacteria were used at concentrations ranging from 10(7) to 10(4) CFU/ml. These results were also observed between C. perfringens and weakly beta-haemolytic intestinal spirochaetes related to animal intestinal spirochaetosis including avian strains and Brachyspira (Serpulina) pilosicoli of porcine origin.

Animals↗