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Preterm birth is the leading cause of neonatal mortality, and is frequently associated with intra-amniotic infection hypothesized to arise from bacterial ascension across a dysfunctional cervical mucus plug. To study this dysfunction, we assessed the permeability of cervical mucus from non-pregnant ovulating (n = 20) and high- (n = 9) and low-risk (n = 16) pregnant women to probes of varying sizes and surface chemistries. We found that the motion of negatively charged, carboxylated microspheres in mucus from pregnant patients was significantly restricted compared to ovulating patients, but not significantly different between high- and low-risk pregnant women. In contrast, charged peptide probes small enough to avoid steric interactions, but sensitive to the biochemical modifications of mucus components exhibited significantly different transport profiles through mucus from high- and low-risk patients. Thus, although both microstructural rearrangements of the components of mucus as well as biochemical modifications to their adhesiveness may alter the overall permeability of the cervical mucus plug, our findings suggest that the latter mechanism plays a dominant role in the impairment of the function of this barrier during preterm birth. We expect that these probes may be readily adapted to study the mechanisms underlying disease progression on all mucosal epithelia, including those in the mouth, lungs, and gut.

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The objective of these studies was to investigate if porcine postweaning multisystemic wasting syndrome (PMWS) could be induced in healthy pigs following contact with air from pigs with clinical signs of PMWS. The pigs were housed in different units. Either 31 (study I) or 25 (study II) pigs with clinical symptoms of PMWS from a PMWS-affected herd and 25 healthy pigs from a PMWS-free, but PCV2-positive, herd were housed in unit A. Fifty pigs from a PMWS-free herd were housed in unit B, which were connected by pipes to unit A. In unit C, 30 pigs from a PMWS-free herd were housed as controls. In study II, the pigs in units A and B from the PMWS-free herd developed clinical signs of PMWS 2-3 weeks after arrival. PMWS was confirmed at necropsy and the diseased pigs had increased PCV2 load and increased antibody titers against PCV2 in serum that coincided with the development of clinical signs typical of PMWS. Sequence analysis revealed that the PCV2 isolate belonged to genotype 2b. In conclusion, the present study showed that PMWS can be induced in pigs from a PMWS-free herd by airborne contact with pigs from a PMWS-affected herd.

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Post-weaning Multisystemic Wasting Syndrome (PMWS) has been identified in most swine-producing countries worldwide. The disease has resulted in significant health challenges and economic damage to the swine industry. The aim of this study was to determine horizontal transmission of porcine circovirus type 2 (PCV2) and to examine viral dynamics in pigs in a controlled PMWS transmission study. In the study pigs from PMWS-affected herds and non-affected herds were permitted to have close contact (same pen), nose-to-nose contact (to pigs in neighbouring pens) or no physical contact (pen across the aisle and pens in other compartments). By DNA sequence analysis, eight variants of genotype PCV-2b were identified in the research facility. From the spread of these PCV2-variants it was concluded that PCV2 primarily infects through close contact and nose-to-nose contact. PCV2 genome sequences were obtained from selected pigs at arrival to the research facility and again when the same pigs developed PMWS. This analysis showed that pigs from PMWS-affected herds developed PMWS caused by the same variant of PCV2 as they carried when entering the research facility. In contrast, pigs from non-affected herds developed PMWS with PCV2-variants identified in pigs from PMWS-affected herds. This was probably connected to at least 10(3) higher mean serum-titer of PCV2 in pigs from PMWS-affected herds as compared to pigs from non-affected herds at the beginning of the transmission study. The study further showed that pigs able to control the PCV2 infection, as measured by the PCV2-titer in serum, recovered clinically (pigs from PMWS-affected herds) or stayed healthy (pigs from non-affected herds). Like this, pigs with a PCV2 titer below 5x10(8) copies/ml serum during the study period had a chance of recover from the PCV2 infection whereas pigs with PCV2 titers above 5x10(8) copies/ml serum at any time point generally died from PMWS.

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Porcine circovirus type 2 (PCV2) is the primary cause of Postweaning Multisystemic Wasting Syndrome (PMWS) in pigs. PCV2, however, is found in both PMWS-affected herds and non-affected herds. The objective of this study was to clarify if PCV2 genome nucleotide sequences isolated from pigs from PMWS-affected herds and non-affected herds cluster phylogenetically in two separate groups. All isolates (45) belonged to PCV2 group 1 and shared a nucleotide sequence identity of 99.4-100% indicating a very homogeneous PCV2 population in Denmark. Phylogenetic analysis of the PCV2 isolates revealed no distinctive clustering of case- and control-herds suggesting that there is no link between PCV2 sequences and herd disease status. The appearance of only PCV2 group 1 isolates in this study (isolates from 2003/2004) led us to determine if PCV2 nucleotide sequences had changed in Denmark over time. Interestingly, all PCV2 isolates from before the first outbreak of PMWS (2001) belonged either to a new PCV2 group identified for the first time in this study and named group 3 (isolates from 1980, 1987 and 1990) or PCV2 group 2 (isolates from 1993 and 1996). The shift from PCV2 group 2 to 1 was confirmed on a more global scale by placing all full genome PCV2 sequences submitted to GenBank from 1997 to 2006 in either of the groups by phylogenetic analysis. The analysis showed that the shift happened in 2003 or even earlier. This may indicate that PCV2 group 1 is a more adapted form of PCV2 and possibly could be more pathogenic.

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AIMS: To identify the main amino acids involved in the Flo11p-mediated adhesion of Saccharomyces cerevisiae to the polystyrene surface PolySorp. METHODS AND RESULTS: Using a combination of phage display and competitive elution revealed that 12-mer peptides of phages from competitive panning with S. cerevisiae FLO11 wild-type (TBR1) cells had a higher consensus than those from competitive panning with S. cerevisiae flo11Delta mutant (TBR5) cells, suggesting that the wild-type cells interact with the plastic surface in a stronger and more similar way than the mutant cells. Tryptophan and proline were more abundant in the peptides of phages from competitive elution with FLO11 cells than in those from competitive elution with flo11Delta cells. Furthermore, two phages with hydrophobic peptides containing 1 or 2 tryptophan, and 3 or 5 proline, residues inhibited the adhesion of FLO11 cells to PolySorp more than a phage with a hydrophobic peptide containing no tryptophan and only two proline residues. CONCLUSIONS: Our results suggest a key role of tryptophan and proline in the hydrophobic interactions between Flo11p on the S. cerevisiae cell surface and the PolySorp surface. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study may contribute to the development of novel strategies to limit yeast infections in hospitals and other medical environments.

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AIMS: To develop PCR assays able to distinguish between groups within lactococcal 936-species bacteriophages, as defined by their different receptor-binding protein (RBP) genes. METHODS AND RESULTS: DNA sequences of RBP genes from 17 lactococcal bacteriophages of the 936-species were compared, and six phage groups were identified. For each phage group a specific primer pair targeting a variable region of the RBP genes was designed. In nine of 20 whey samples, from dairies with recorded phage problems, between one and six phage groups were identified by conventional PCR. The sensitivity and specificity of the method was improved by magnetic capture hybridization (MCH)-PCR using a capture probe targeting an 80-bp highly conserved region just upstream from the RBP gene in all the investigated phages. The MCH-PCR was performed on 100 microl whey samples and the detection limit of the assay was 10(2)-10(3) PFU ml(-1) as opposed to the detection limit of 10(4) PFU ml(-1) for conventional PCR performed on 1-microl whey samples. CONCLUSIONS: In this study, PCR assays have been developed to detect six different types of RBP genes in lactococcal 936-species bacteriophages. SIGNIFICANCE AND IMPACT OF THE STUDY: The PCR assays have practical applications at cheese plants for detection of 936-species phages with different RBP and thereby potentially with different host ranges. This knowledge will make it possible to improve starter culture rotation systems in the dairy industry.

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