The bacterial species Staphylococcus aureus, including its methicillin-resistant variant (MRSA), finds its primary ecological niche in the human nose, but is also able to colonize the intestines and the perineal region. Intestinal carriage has not been widely investigated despite its potential clinical impact. This review summarizes literature on the topic and sketches the current state of affairs from a microbiological and infectious diseases' perspective. Major findings are that the average reported detection rate of intestinal carriage in healthy individuals and patients is 20% for S. aureus and 9% for MRSA, which is approximately half of that for nasal carriage. Nasal carriage seems to predispose to intestinal carriage, but sole intestinal carriage occurs relatively frequently and is observed in 1 out of 3 intestinal carriers, which provides a rationale to include intestinal screening for surveillance or in outbreak settings. Colonization of the intestinal tract with S. aureus at a young age occurs at a high frequency and may affect the host's immune system. The frequency of intestinal carriage is generally underestimated and may significantly contribute to bacterial dissemination and subsequent risk of infections. Whether intestinal rather than nasal S. aureus carriage is a primary predictor for infections is still ill-defined.

Nucleic Acids Res. 20:3925-3931, 1992). Here we show that rad7 as well as rad7 rad16 double mutants have the same repair phenotype, indicating that the RAD7 and RAD16 gene products might operate in the same nucleotide excision repair subpathway. Dimer removal from the genome overall is essentially incomplete in these mutants, leaving about 20 to 30%Yo of the DNA unrepaired. Repair analysis of the transcribed RPB2 gene shows that the nontranscribed strand is not repaired at all in rad7 and radl6 mutants, whereas the transcribed strand is repaired in these mutants at a fast rate similar to that in RAD' cells. When the results obtained with the RPB2 gene can be generalized, the RAD7 and RAD16 proteins not only are essential for repair of silenced regions but also function in repair of nontranscribed strands of active genes in S. cerevisiae. The phenotype of rad7 and radl16 mutants closely resembles that of human xeroderma pigmentosum complementation group C (XP-C) cells, suggesting that RAD7 and RAD16 in S. cerevisiae function in the same pathway as the XPC gene in human cells. RAD4, which on the basis of sequence homology has been proposed to be the yeast XPC counterpart, seems to be involved in repair of both inactive and active yeast DNA, challenging the hypothesis that RAD4 and XPC are functional homologs.

The nucleotide excision repair (NER) pathway is thought to consist of two subpathways: transcription-coupled repair, limited to the transcribed strand of active genes, and global genome repair for nontranscribed DNA strands. Recently we cloned the RAD26 gene, the Saccharomyces cerevisiae homolog of human CSB/ERCC6, a gene involved in transcription-coupled repair and the disorder Cockayne syndrome. This paper describes the analysis of yeast double mutants selectively affected in each NER subpathway. Although rad26 disruption mutants are defective in transcription-coupled repair, they are not UV sensitive. However, double mutants of RAD26 with the global genome repair determinants RAD7 and RAD16 appeared more UV sensitive than the single rad7 or rad16 mutants but not as sensitive as completely NER-deficient mutants. These findings unmask a role of RAD26 and transcription-coupled repair in UV survival, indicate that transcription-coupled repair and global genome repair are partially overlapping, and provide evidence for a residual NER modality in the double mutants. Analysis of dimer removal from the active RPB2 gene in the rad7/16 rad26 double mutants revealed (i) a contribution of the global genome repair factors Rad7p and Rad16p to repair of the transcribed strand, confirming the partial overlap between both NER subpathways, and (ii) residual repair specifically of the transcribed strand. To investigate the transcription dependence of this repair activity, strand-specific repair of the inducible GAL7 gene was investigated. The template strand of this gene was repaired only under induced conditions, pointing to a role for transcription in the residual repair in the double mutants and suggesting that transcription-coupled repair can to some extent operate independently from Rad26p. Our findings also indicate locus heterogeneity for the dependence of transcription-coupled repair on RAD26.

The gut microbiota of infants is shaped by both the mode of delivery and the type of feeding. The gut of vaginally and cesarean-delivered infants is colonized at different rates and with different bacterial species, leading to differences in the gut microbial composition, which may persist up to 6 months. In a multicenter, randomized, controlled, double-blind trial conducted in South Africa, we tested the effect of a formula supplemented with a prebiotic (a mixture of bovine milk-derived oligosaccharides [BMOS] generated from whey permeate and containing galactooligosaccharides and milk oligosaccharides such as 3′- and 6′-sialyllactose) and the probiotic Bifidobacterium animalis subsp. lactis (B. lactis) strain CNCM I-3446 on the bifidobacteria levels in the gut of infants born vaginally or via cesarean section in early life. Additionally, the safety of the new formulation was evaluated. A total of 430 healthy, full-term infants born to HIV-positive mothers who had elected to feed their child beginning from birth (≤3 days old) exclusively with formula were randomized into this multicenter trial of four parallel groups. A total of 421 infants who had any study formula intake were included in the full analysis set (FAS). The first two groups consisted of cesarean-delivered infants assigned to the Test formula (n = 92) (a starter infant formula [IF] containing BMOS at a total oligosaccharide concentration of 5.8 ± 1.0 g/100 g of powder formula [8 g/L in the reconstituted formula] + B. lactis [1 × 107 colony-forming units {cfu}/g]) or a Control IF (n = 101); the second two groups consisted of vaginally delivered infants randomized to the same Test (n = 115) or Control (n = 113) formulas from the time of enrollment to 6 months. The primary efficacy outcome was fecal bifidobacteria count at 10 days, and the primary safety outcome was daily weight gain (g/d) between 10 days and 4 months. At 10 days, fecal bifidobacteria counts were significantly higher in the Test formula than in the Control formula group among infants with cesarean birth (median [range] log: 9.41 [6.30–10.94] cfu/g versus 6.30 [6.30–10.51] cfu/g; P = 0.002) but not among those with vaginal birth (median [range] log: 10.06 [5.93–10.77] cfu/g versus 9.85 [6.15–10.79] cfu/g; P = 0.126). The lower bound of the two-sided 95% confidence interval of the difference in the mean daily weight gain between the Test and Control formula groups was more than –3 g/d in both the vaginally and cesarean-delivered infants, indicating that growth in the Test formula-fed infants was not inferior to that of Control formula-fed infants. At 10 days and 4 weeks, the fecal pH of infants fed the Test formula was significantly lower than in those fed the Control formula, irrespective of mode of delivery: for vaginal delivery: 4.93 versus 5.59; P < 0.001 (10 days) and 5.01 versus 5.71; P < 0.001 (4 weeks); for cesarean delivery: 5.14 versus 5.65, P = 0.009 (10 days) and 5.06 versus 5.75, P < 0.001 (4 weeks). At 3 months, this acidification effect only persisted among cesarean-born ...

In a pilot study, the feasibility of immune whey protein concentrate (40 %; immune WPC-40) to aid the prevention of relapse of Clostridium difficile diarrhoea was evaluated. Immune WPC-40 was made from milk after immunization of Holstein-Frisian cows with C. difficile-inactivated toxins and killed whole-cell C. difficile. Immune WPC-40 contained a high concentration of specific sIgA antibodies, and was effective in neutralizing the cytotoxic effect of C. difficile toxins in cell assays in vitro. Immune WPC-40 conferred protection from otherwise lethal C. difficile-associated caecitis in hamsters. To obtain preliminary data in humans, 16 patients (10 male; median 57 years) with toxinand culture-confirmed C. difficile diarrhoea were enrolled in an uncontrolled cohort study. Nine had a history of relapsing C. difficile diarrhoea. After completion of standard antibiotic treatment, the patients received immune WPC-40 TID for 2 weeks; it was well tolerated and no treatment-related adverse effects were observed. In all but one case, C. difficile toxins had disappeared from the faeces upon completion of treatment. During a follow-up period of median 333 days (range 35 days to 1 year), none of the patients had suffered another episode of C. difficile diarrhoea. These preliminary data suggest that immune whey protein concentrate-40 may be of help in the prevention of relapse of C. difficile diarrhoea.