Bacterial and fungal microflora in surgically removed lung cancer samples

<p>Abstract</p> <p>Background</p> <p>Clinical and experimental data suggest an association between the presence of bacterial and/or fungal infection and the development of different types of cancer, independently of chemotherapy-induced leukopenia. This has also been postulated for the development of lung cancer, however the prevalence and the exact species of the bacteria and fungi implicated, have not yet been described.</p> <p>Aim</p> <p>To determine the presence of bacterial and fungal microflora in surgically extracted samples of patients with lung cancer.</p> <p>Materials and methods</p> <p>In this single-center prospective, observational study, tissue samples were surgically extracted from 32 consecutive patients with lung cancer, and reverse-transcription polymerase chain reaction (RT-PCR) was used to identify the presence of bacteria and fungi strains.</p> <p>Results</p> <p>The analysis of the electrophoresis data pointed out diversity between the samples and the strains that were identified. Mycoplasma strains were identified in all samples. Strains that appeared more often were Staphylococcus epidermidis, Streptococcus mitis and Bacillus strains, followed in descending frequency by Chlamydia, Candida, Listeria, and Haemophilus influenza. In individual patients Legionella pneumophila and Candida tropicalis were detected.</p> <p>Conclusions</p> <p>A diversity of pathogens could be identified in surgically extracted tissue samples of patients with lung cancer, with mycoplasma strains being present in all samples. These results point to an etiologic role for chronic infection in lung carcinogenesis. Confirmation of these observations and additional studies are needed to further characterize the etiologic role of inflammation in lung carcinogenesis.</p

Isolation, cultivation and identification of Borrelia burgdorferi genospecies from Ixodes ricinus from the city of Brno, Czech Republic

A total of 305 ticks (21 larvae, 243 nymphs, 19 females and 22 males) were collected by fl agging of vegetation in suburban woods of Pisárky Park (city of Brno) from July to October 2002. The midgut of each tick was dissected out and transferred individually into BSK-H medium. After cultivation, all specimens were examined by dark-fi eld microscopy (DFM) for the presence of borreliae. Out of 305 tick samples, 45 were (14.8%) DFM positive. The following polymerase chain reaction (PCR) then revealed 37 (12.1%) samples positive for the presence of Borrelia burgdorferi sensu lato DNA. All 37 samples were further analysed by restriction fragment length polymorphism (RFLP) method. PCR-RFLP analysis revealed 14 strains of B. afzelii (37.8%), 15 strains of B. garinii (40.5%) and 2 strains of B. burgdorferi sensu stricto (5.4%). Four samples (10.8%) showed a mixed population of these genospecies. Two samples produced atypical RFLP pattern which were detected by sequence analysis as B. valaisiana (5.4%). Isolation attempts resulted in 21 spirochaetal strains (including two stains of B. valaisiana). The results show the diversity of B. burgdorferi s.l. in tick population and refer the risk of infection by pathogenic borreliae in Brno

PCR Diagnosis of Invasive Candidiasis: Systematic Review and Meta-Analysis▿†

Invasive candidiasis (IC) is a significant cause of morbidity and mortality. Diagnosis relies on culture-based methods, which lack sensitivity and delay diagnosis. We conducted a systematic review assessing the diagnostic accuracy of PCR-based methods to detect Candida spp. directly in blood samples. We searched electronic databases for prospective or retrospective cohort and case-control studies. Two reviewers abstracted data independently. Meta-analysis was performed using a hierarchical logistic regression model. Random-effects metaregression was performed to assess the effects of study methods and infection characteristics on sensitivity or specificity values. We included 54 studies with 4,694 patients, 963 of whom had proven/probable or possible IC. Perfect (100%) sensitivity and specificity for PCR in whole-blood samples was observed when patients with cases had candidemia and controls were healthy people. When PCR was performed to evaluate patients with suspected invasive candidiasis, the pooled sensitivity for the diagnosis of candidemia was 0.95 (confidence interval, 0.88 to 0.98) and the pooled specificity was 0.92 (0.88 to 0.95). A specificity of >90% was maintained in several analyses considering different control groups. The use of whole-blood samples, rRNA, or P450 gene targets and a PCR detection limit of ≤10 CFU/ml were associated with improved test performance. PCR positivity rates among patients with proven or probable IC were 85% (78 to 91%), while blood cultures were positive for 38% (29 to 46%). We conclude that direct PCR using blood samples had good sensitivity and specificity for the diagnosis of IC and offers an attractive method for early diagnosis of specific Candida spp. Its effects on clinical outcomes should be investigated