, 2000) Not surprisingly, the genome

, 2000). Not surprisingly, the genome Volasertib chemical structure contained a high number of genes involved in catabolism, transport, efflux, motility, and signal response regulation. In fact, over 8% of genes in the P. aeruginosa (PAO1) genome were thought to be involved in regulation, which well exceeded the percentage observed in any other bacterial genome. It was immediately clear that the key to Pseudomonas’s success

was the plasticity with which it could express its genes, which was afforded by layers of regulatory complexity. Since 2000, the vast majority of the 1000+ Pseudomonas genomes sequenced have been clinical strains of P. aeruginosa. Collectively, we have learned that the major part of the P. aeruginosa genome (about 4000 genes) is conserved in all strains and represents the ‘core genome’. Up to another 20% of genes reside on genomic islands that collectively represent the ‘accessory genome’. It is this accessory genome that imparts P. aeruginosa’s plasticity and includes many of the genes involved in metabolism, virulence, and antibiotic resistance. As approximately 10 000 unique genes have already been identified in the accessory regions of sequenced isolates, it is estimated that the P. aeruginosa pan-genome could approach, or even exceed, 100 000 genes, meaning that the genetic repertoire of this one species

of Pseudomonas would far ABT-737 ic50 exceed that of humans (Tummler et al., 2014). In this thematic issue, Sarah Pohl et al. (Pohl et al., 2014) analyzed the expression of the accessory genome of 150 P. aeruginosa clinical isolates. Despite the 10 000 unique genes that have already been sequenced from the accessory regions of P. aeruginosa clinical isolates, the investigators found that almost all of their 150 isolates possessed genes not present in any previously sequenced. Their findings further demonstrate the exceptionally broad P. aeruginosa gene pool. Considering the vast genomic variation in the genus, it is not surprising that there is still much we do

not understand about the relationship between genetic composition and the behavior of pseudomonads. Many of the contributions in this thematic medroxyprogesterone issue focus on topics in this area. In his MiniReview, Valentin Rybenkov (Rybenkov, 2014) discusses how the replication, organization, and segregation of the P. aeruginosa chromosome add further complexity to the regulation of the transcriptome. The genetic and phenotypic consequences of plasmids on P. aeruginosa, P. putida, and P. stutzeri are investigated in three different reports by Deraspe et al., (2014) Silva-Rocha and de Lorenzo (2014) and Coleman et al., (2014) respectively, while contributions from Song et al. (2014) and González-Valdez et al. (2014) report new findings that influence the regulation of lipopeptide biosynthesis in P. fluorescens and quorum sensing in P. aeruginosa. In all, 12 original reports and MiniReviews are included in this thematic Pseudomonas issue of FEMS Microbiology Letters.

, 2005, 2008; Nguyen et al, 2007) Whereas previous studies have

, 2005, 2008; Nguyen et al., 2007). Whereas previous studies have examined wag31-dependent functions by expressing the gene with an acetamide-inducible promoter (Kang et al., 2008), a tetracycline-inducible promoter (Hamasha et al., 2009), or a heat shock promoter (Kang et al., 2005), this current study is the first

to examine wag31Mtb expression using its native promoter. This promoter appears to be upregulated by the mycobacterial stringent response (Figs 1 and 2). The stringent response is necessary for persistent M. tuberculosis infections GDC0449 in mammalian hosts (Dahl et al., 2003; Klinkenberg et al., 2010). Here, we report that the stringent response is needed for higher expression of wag31, suggesting a potential connection between Wag31 and virulence. Although Wag31 is involved in mycobacterial cell wall synthesis, Wag31 may be playing some alternative roles during the infection process. Cao et al. (2008) recently reported that Wag31Mtb stimulates XCL2 expression in macrophages. XCL2 is a chemokine in macrophages that serves as a chemoattractant for CD8+ and CD4+ T cells. Therefore, wag31Mtb expression may contribute to

the formation of granulomas that are extremely diminished in size Fulvestrant concentration and in numbers in animals infected with M. tuberculosisΔrel strains (Dahl et al., 2003; Klinkenberg et al., 2010). Although traditionally thought to function as a host defense strategy, the role of the granuloma is being re-evaluated as providing a potential benefit to mycobacterial pathogens (Flynn, 2004).

Also, elevated wag31 expression may enhance M. tuberculosis survival in macrophages by enhancing resistance to oxidative stress. Wag31 may do this by stabilizing penicillin-binding protein 3 (PBP3) against cleavage by the M. tuberculosis metalloprotease Rv2869c. This metalloprotease is essential for M. tuberculosis cells Bumetanide to infect mice lungs, and it likely acts to regulate the bacterial lipid and membrane composition necessary for survival in the host (Madinoshima & Glickman, 2005). However, without protection by Wag31 binding, PBP3 is susceptible to deleterious cleavage by Rv2869c, leading to reduced survival of M. tuberculosis within macrophages (Mukherjee et al., 2009). We thank Christine Davitt for assistance with TEM analysis, Gerhard Munske for help with proteomic identification of Wag31, and Mike Konkel for assistance with antibody production. This research was supported by internal funds from the University of Minnesota Duluth. “
“Eradication of Helicobacter pylori with traditional therapy often fails in clinical treatment. As a result, a novel efficacious therapeutic agent is strongly needed. Allitridi, a proprietary garlic derivative, has been successfully used to treat both systemic fungal and bacterial infections in China. Our previous study has shown a dose-dependent inhibitory effect of allitridi on H. pylori growth. However, the antibacterial mode of action of allitridi is still unclear.

In notothenioid fish, gene duplications that enhance gene express

In notothenioid fish, gene duplications that enhance gene expression play an important role in adaptation to the Antarctic environments (Chen et al., 2008). As we found a slightly higher copy number of hiC6 in NJ-7 than UTEX259, it would be interesting to isolate more C. vulgaris

strains with a lower freezing tolerance and determine whether the copy number of hiC6 would decrease to one to about three accordingly. We also wondered whether all copies of hiC6 in the tandem array were identically expressed. Because hiC6 genes have almost identical mRNA sequences, their expression can barely be distinguished by Northern blot hybridization. We employed gene-specific primers to perform RT-PCR detections and, in addition, calculated the relative transcript abundance based on sequences of total hiC6 MK 2206 cDNAs. Our results showed that the tandem-arrayed genes were differentially expressed in both strains. In NJ-7, almost all hiC6 transcripts were expressed from NJ7hiC6-3, -4 and -5, whereas in UTEX259, hiC6 transcripts were essentially expressed from 259hiC6-1, -3 and -4. Therefore, the formation of the tandem array

of hiC6 does not appear to be a simple process of gene duplications but takes place in combination with gene expression divergence. In an Antarctic green alga species, the nitrate reductase showed a lower maximal temperature compared to that of a temperate Acalabrutinib species (di Rigano et al., 2006). This finding suggests that proteins can be evolved to promote the adaptation to Antarctic environments. We wondered whether amino acid substitutions within HIC6 can enhance the freezing tolerance of C. vulgaris. In vitro assays showed that different HIC6 isoforms

provided similar protection of LDH from inactivation by freeze and thaw. Therefore, compared to changes in gene expression level, accumulation of substitutions to enhance the cryoprotective activities of LEA proteins is probably a much slower process for adaptation to the Antarctic environments. In addition to HIC6 and HIC12, we have very recently identified two novel cold-inducible LEA proteins, Ccor1 and Ccor2, in NJ-7 (Liu et al., 2011). Probably, more LEA clonidine proteins remain to be identified. These proteins may exert cumulative effects on the freezing tolerance of Chlorella. Alternatively, they may be involved in protection of enzymes or membranes of different cellular structures and play independent roles in freezing tolerance. For example, HIC6 seemed to be localized to mitochondria in transgenic plants (Honjoh et al., 2001). Further analyses of these LEA proteins and their encoding genes should be very useful for an in-depth understanding of the development of freezing tolerance in the Antarctic Chlorella. This research was supported by the Key Projects KSCX2-YW-G-060 and KSCX2-SW-332 of Knowledge Innovation Program of Chinese Academy of Sciences. “
“A self-subunit swapping chaperone is crucial for cobalt incorporation into nitrile hydratase.

Thus, the study of HPV genotypes coexisting in the anal canal is

Thus, the study of HPV genotypes coexisting in the anal canal is of high relevance in HIV-infected men, in order to establish further preventive protocols in this specific population

at risk. The aim of this work was to assess the prevalence BAY 80-6946 clinical trial of anal condylomata and their association with HPV genotype-specific infection and cytological abnormalities in the anal canal in HIV-infected men (MSM and heterosexuals). A cross-sectional analysis based on the first (baseline) visit of patients in the Can Ruti HIV-positive Men (CARH·MEN) cohort was performed (University Hospital Germans Trias i Pujol, Badalona, Spain). This cohort was a prospective, single-centre of out-patient HIV-positive men who were annually assessed for HPV infection in the anus, penis and mouth. The protocol, amendments and other materials were approved by the hospital’s independent ethics committee. Consecutive patient recruitment among out-patients who attended their clinical routine control was carried out by one Smoothened Agonist staff care provider from 2005 to 2007 and since 2008 has been carried out by two staff care providers. The patients were informed about the study and invited to visit the Clinical Proctology HIV Unit which was created ad hoc (two afternoons per week). If they agreed to participate,

written informed consent was obtained. HIV-positive men ≥ 18 years old, without a history of (or current) anal cancer, were included in the study. The following data were collected: date of birth, date of HIV-positive diagnosis (time of HIV infection in years), baseline CD4 cell count (the closest value obtained during the participants’ usual clinical

follow-up visits in the HIV Unit before the cytological sample collection), CD4 count nadir (the lowest CD4 value for each patient abstracted from medical records), HIV viral load (the closest value obtained before the sample aminophylline collection), highly active antiretroviral therapy (HAART) previous to inclusion (yes/no) and time on HAART, history of sexually transmitted infections (STIs), alcohol and smoking history, sexual behaviour and number of sexual partners. Baseline CD4 count and CD4 count nadir were determined by flow cytometry, and HIV viral load by Nuclisens (detection limit 80 HIV-1 RNA copies/mL; bioMerieux, Inc., Durham, NC). A clinical examination (visual inspection) and a digital rectal examination were performed at the baseline visit of patients in the CARH·MEN cohort. Samples from the anal canal were collected for detection of HPV infection [multiplex polymerase chain reaction (PCR)]. The anal canal sample was also used to carry out the cytology analysis (Pap test). If the anal cytology result showed a pathological finding, the patient was contacted and informed, and a high-resolution anoscopy (with topical application of 2 minutes of duration with 3% acetic acid to the anal canal) was scheduled.

In order to measure the transcript levels of proteins identified

In order to measure the transcript levels of proteins identified in this study, seven genes out of 18 were selected for RT-PCR in the wild-type L. monocytogenes and ΔsigB mutant and the relative mRNA levels were measured. To quantify mRNA levels, the band density of each PCR product was measured after agarose gel electrophoresis. As shown in Fig. 2, the transcript levels are consistent with the proteomic data. Moreover, transcription of the identified genes, including gyrB, lmo1374, ftsA Copanlisib chemical structure and lmo2779, are directly or indirectly under the control of σB. No RT-PCR products were observed in the negative

control (data not shown). Caspase activation The role of the L. monocytogenesσB under stress conditions has been studied intensively, especially under osmotic, cold, acid, high hydrostatic pressure or oxidative stress (Cole et al.,

1990; Sleator et al., 2001; Wemekamp-Kamphuis et al., 2004). Recently, the relationship between alternative sigma factor and antimicrobial resistance has been reported in various bacteria. In B. subtilis, sigma factors σM, σW and σX contribute to resistance to various cell envelope-targeting antibiotics (Mascher et al., 2007). In addition, σB contributes to the upregulation of its own regulon upon exposure to bacitracin or vancomycin (Mascher et al., 2003). In L. monocytogenes, σB is important for growth and survival upon treatment with bacteriocin (lacticin 3147 and nisin) or antibiotics (penicillin G and ampicillin) (Begley et al., 2006). According to a recent report, both σB and σL contribute to tolerance DOCK10 to the antimicrobial peptide SdpC and the bacteriocin nisin in L. monocytogenes (Palmer et al., 2009). Antibiotic-induced cell wall stress is known to induce the expression of many genes. In our two independent proteomic analyses, 18 vancomycin-inducible proteins were identified with minimum twofold upregulation in

the wild-type L. monocytogenes compared with the ΔsigB mutant. Among these proteins, Lmo0539, Lmo0524, Lmo2085, Lmo2114, Pgm, InlD, Lmo1027 and Lmo0079 were already confirmed to be σB-dependent proteins induced under salt or stationary-phase stress (Kazmierczak et al., 2003; Raengpradub et al., 2008; Oliver et al., 2009). Among the three transporter proteins identified under vancomycin stress, Lmo0524 and Lmo1431 were induced only in wild-type L. monocytogenes, whereas Lmo2114 showed a 3.5-fold increase in the wild-type strain (Table 2). Indeed, bacitracin treatment highly stimulated the bceAB gene, which encodes a putative ABC transporter in B.

Therefore, this study was carried out in order to evaluate substa

Therefore, this study was carried out in order to evaluate substance use and sexual risk behaviour in a large German sample of HIV-positive MSM receiving specialized medical treatment. Results will be an empirical basis for the development of prevention strategies working with MSM diagnosed with HIV infection (‘prevention with positives’). Data were collected between January 2009 and February 2010. Participants were recruited in two specialized HIV out-patient clinics at university hospitals

in Germany. The interviewers, the attending physicians or nurses asked CH5424802 chemical structure patients if they wished to participate in a survey on sexual behaviour and substance use. Any interested patient received an information sheet on the study’s aims and content and on privacy. Participants signed an informed consent form; attendance was voluntary and without payment. Only HIV-positive MSM, who had known of their HIV-seropositive status for at least 12 months, were included. Exclusion criteria were insufficient German language ability and/or an acute psychotic disorder. A psychologist and trained medical students conducted the interviews. The ethics committee of the Medical Faculty at the University Duisburg-Essen, Essen, Germany, approved the study. Alcohol and illicit drug use Tanespimycin in vitro were examined using the German version of the semi-standardized interview European Addiction Severity Index

(Europ-ASI) [38]. Questions regarding sexual behaviour were based on the German KABaSTI Study of the Robert Koch Institute [39]. In addition, questions were asked regarding substance use in the immediate context of sexual behaviour: patients were asked buy Metformin whether they themselves or their sexual partners had consumed illicit drugs or alcohol until drunkenness immediately

before or during sexual intercourse in the last 12 months. First, we hypothesized that current substance use is associated with unprotected sexual intercourse. We differentiated between any unprotected sexual intercourse (including oral sex, which is less relevant for HIV transmission) and insertive and receptive anal sex. Secondly, we hypothesized that substance use in the immediate context of sexual activity is associated with unprotected sexual contacts. For the statistical analyses, spss® 17.0 (SPSS, Chicago, IL) was used. For group comparisons, the χ2 test or Fisher’s exact test was applied. If they fulfilled the criteria of normality and homoscedasticity, means were compared using a t-test for independent samples. In cases where these preconditions were not met, the nonparametric Mann–Whitney U-test was applied. In order to allow statements to be made regarding the 12-month prevalence of sexual risk behaviour, the analysis is solely based on those participants who had been sexually active during the 12-month period prior to the interview.

Studies that were identified as potentially relevant were initial

Studies that were identified as potentially relevant were initially screened (1329) after duplicates were removed. A total of 54 articles, abstracts and research papers were selected for full-text assessment from which 22 were included in this review after screening by two reviewers (a research assistant and the lead author PD) (see Figure 1, a flow diagram outlining the steps). The selected articles met at least one of the main criteria for this review by presenting data on barriers or facilitators and attitudes in relation to pharmacy professionals’ participation GDC-0068 in

CPD and/or mapping engagement with and uptake of CPD in pharmacy in GB. In relation to research papers, studies were excluded if the focus was on a different group of health professionals with no orientation towards pharmacy. Papers were excluded find more if the focus

was simply on CE or professionalism per se or if the focus was only on the pharmacy student cohort. Studies were also excluded if the country of focus was outside of GB; i.e. studies conducted in Northern Ireland were excluded. In addition, papers were excluded if the focus was purely on subsets of skills usually associated with CPD, such as reflective learning by itself, or on actual content relating to CPD, for example learning clinical pharmacy. We did not include in the review a study examining feedback on CPD provided by RPSGB because this very specific study did not investigate general attitudes to CPD but was instead a form of ‘satisfaction with feedback study’. We did nonetheless acknowledge the contribution of this study to the field in the discussion section of this paper. We did not include any studies

published or relating to the period before 2000 but viewed them as providing context ahead of the launch of CPD. A grid was created to record the summaries of the articles for further literature synchronisation and later construction of the literature review. This took the form of a data extraction form that enabled inclusion of studies based on eligibility in the first instance and then quality assessment at a later stage (see below). Astemizole This initial tabulation presented information on study characteristics as the year study was conducted; main study design and method of data collection; sector of pharmacy; geographical location of the study; the sample size; and a brief summary of the aims. It was not possible to use the PICOS (participants, interventions, comparisons, outcomes and study design) categorisation[19] because the studies were not necessarily interventional in nature. Instead quality scoring of the articles was attempted in accordance to the recommendations of the Qualitative Assessment Review Instrument (QARI) [20] (suggested by the Cochrane Collaboration).

HIV diagnosis during pregnancy may be a profoundly shocking and l

HIV diagnosis during pregnancy may be a profoundly shocking and life-changing experience for the newly diagnosed HIV-positive woman. There may be a complex mix of emotional, psychosocial, relationship, economic and even legal issues that arise directly out of the HIV diagnosis. The newly diagnosed woman also has

a relatively brief time in which she needs to be able to develop trust in her medical carers and attain sufficient medical knowledge of her situation to be able to make informed decisions that will affect the long-term health of herself, her fetus and her male partner. Prevention of MTCT can only be achieved if the pregnant woman embraces the medical interventions appropriately. To maximize the effectiveness of the interventions for pregnant women in reducing MTCT the psychosocial context of their HIV infection find more must not be overlooked. Clinical experience indicates that the management of issues including dealing with the diagnosis and uncertainty during pregnancy and robust confidentiality processes have an impact on adherence Selleck Alpelisib to ART and acceptance of recommended interventions and all clinicians must be mindful of

this. Studies from around the world have shown significant prevalence of intimate partner violence in pregnancy (14% in the UK to 63% in Zimbabwe), which seems to be greater in women who are HIV positive. NICE antenatal guidelines recommend asking all pregnant women about domestic violence and this would be even more important in women with HIV (especially those with a recent diagnosis or a positive partner) [336–338]. 9.1 Antenatal HIV care should be delivered by a multidisciplinary team (MDT), the precise composition of which will vary. Grading: 1D The minimum team would comprise an HIV specialist, obstetrician, specialist midwife and paediatrician, with the recommendation of peer- and voluntary-sector support. All efforts should be made to involve the woman’s GP and health visitor. It may be necessary to involve some of the following: patient advocates, social workers, legal advocacy, clinical EGFR inhibitor psychologists, psychiatrists, counsellors, health advisors, Citizens Advice Bureau

workers, interpreters, community midwives, clinical nurse specialists and health visitors [339]. In settings with relatively few HIV-positive pregnant women, it is still important to develop robust pathways of care with identified members of an MDT. Regular links, formal or informal, can also be established with a larger unit to provide advice and support as necessary. Good communication is vital in view of the complexity of the issues involved. An early assessment of the social circumstances of a newly diagnosed HIV-positive woman is important. Patients who initially refuse interventions or default from follow-up need to be identified and actively followed-up. Support by trained peer-support workers is a valuable component of the management of HIV-positive pregnant women.

, 2007; Zhou et al, 2009; da Miguel et al, 2010),


, 2007; Zhou et al., 2009; da Miguel et al., 2010),

such methods may provide an inaccurate description of the total microbial structure in that they reveal only dominant populations, which may not necessarily Proteasome inhibitors in cancer therapy play important roles in overall community dynamics. Lacticin 3147 is a potent, two-peptide broad spectrum lantibiotic (class I bacteriocin or antimicrobial peptide) produced by Lactococcus lactis DPC3147 (Fig. 1; Ryan et al., 1996; Martin et al., 2004; Lawton et al., 2007). First isolated from an Irish kefir grain in 1996, it is perhaps one of the most extensively studied bacteriocins and has been shown to inhibit such clinically relevant pathogens as Clostridium difficile, R788 methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci (Rea et al., 2007; Piper et al., 2009). Although the microbial composition of kefir grains has been well documented (Rea et al., 1996; Ninane et al., 2007;

Zhou et al., 2009), to our knowledge, there have been no reports on the characterization of the microbiota of a kefir grain from which bacteriocin-producing strains have been isolated. In recent years, the field of microbial ecology has been revolutionized by the development and application of high-throughput DNA sequencing technologies, such as that facilitated by the 454 GS-FLX platform (Roche Diagnostics Ltd, West Sussex, UK; Keijser et al., 2008; Urich et al., 2008; McLellan et al., 2009), which allows for a more complete view of overall community composition without the bias typically associated with cloning or cultivation. Here, we use high-throughput sequencing of 16S rRNA gene amplicons to characterize the bacterial composition of the original Irish kefir from which L. lactis DPC3147 was initially isolated. The kefir grain starter used in this study was obtained from the Teagasc Food Research Centre (Fig. 1a; Teagasc, Fermoy, Ireland) kefir grain collection. The grain was cultured in sterile 10%

reconstituted skim milk at 21 °C for 24 h. The fermented Urocanase kefir milk was removed and the grain rinsed with sterile water to remove any clotted milk still adhered onto the grain surface. In order to monitor bacterial changes over the course of the kefir fermentation, kefir milk samples were enumerated for lactococci and lactobacilli; populations typically associated with the kefir community. Samples were first homogenized as 10-fold serial dilutions, further 10-fold serial dilutions were prepared and appropriate dilutions were spread plated onto M17 agar supplemented with 0.5% lactose (LM17; Difco Laboratories, Detroit, MI) for lactococci, and Lactobacillus selection agar (LBS; Difco) for lactobacilli populations. LM17 plates were incubated aerobically at 30 °C overnight and LBS plates were incubated anaerobically at 37 °C for 5 days.

1a and d) Therefore, it is possible that the extracellular prote

1a and d). Therefore, it is possible that the extracellular protease is one of major antibiofilm components in the supernatants of P. aeruginosa strains. Although it is known that both endogenous and exogenous proteases dispersed established

biofilms (Boles & Horswill, 2008; Iwase et al., 2010), it remains unclear how the proteases rapidly disperse S. aureus biofilm and what the target of the protease is. Hence, we hypothesized that the presence of protease induced the expression of endogenous protease genes in S. aureus. To investigate this hypothesis, a further protease activity assay and transcriptional assay were performed. When the proteinase K was added in the two S. aureus strains, the S. aureus cells clearly increased the protease activity compared to that

of proteinase K only (Fig. 2b and c). Specifically, the addition of proteinase K (0.01 mg mL−1) Selleck RGFP966 increased the lytic zone more than threefold with both S. aureus ATCC 25923 and S. aureus ATCC 6538. The result indicates that the exogenous protease could induce the expression of protease genes in S. aureus. Additionally, qRT-PCR was performed to study the gene expression of proteases with the supernatant of P. aeruginosa containing the protease activity. The supernatant of P. aeruginosa PAO1 clearly induced the gene expression of five major proteases (aur, clp, scpA, splA, and sspA; Fig. 3a). Particularly, splA was induced 61-fold by the CDK inhibitor Adenylyl cyclase treatment of P. aeruginosa PAO1 supernatant than without treatment. Also, further qRT-PCR showed that the P. aeruginosa PAO1 supernatant induced quorum-sensing agrA, hemolysin hla, and histidine protein kinase saeS, but not icaA (Fig. 3b). This result supports the previous report that protease activity is mediated in the agr quorum-sensing system but in an ica-independent manner (Boles & Horswill, 2008). To identify the main antibiofilm protease in P. aeruginosa, the supernatants of various protease-deficient mutants

of P. aeruginosa were tested for the biofilm reduction in S. aureus. Interestingly, two mutants (lasB and rhlR) showed much lower activity of protease in the milk agar plate (Fig. 2d) and also had much lower antibiofilm activity against S. aureus (Fig. 4), while other eleven protease mutants including lasA mutant showed high protease activity as well as antibiofilm activity. The lasB gene encodes LasB elastase, and the rhlR gene encodes a transcriptional activator protein of the rhl quorum-sensing system that is necessary for the production of LasA protease, LasB protease, Apr alkaline protease, pyocyanin, cyanide, and rhamnolipid (Van Delden & Iglewski, 1998). Because both lasB mutant and rhlR mutant are deficient in the production of LasB elastase, it appears that LasB elastase is one of major antibiofilm protease in the supernatant of P. aeruginosa against S. aureus.