Follicle Stimulating Hormone (FSH) as a Predictor of Decreased Oocyte Yield in Patients with Normal Anti-Müllerian Hormone (AMH) and Antral Follicle Count (AFC).

Background: The purpose of the current study was to determine the utility of early follicular phase follicle-stimulating hormone (FSH) testing in patients undergoing in vitro fertilization (IVF). Methods: This was a retrospective review of patients from 2012 to 2015 at Mayo Clinic in Rochester, Minnesota, USA. Included subjects had a normal anti-Müllerian hormone (AMH) of 1 to 9 ng/ml and antral follicle count (AFC) of 10 to 29. Patients were stratified by FSH level when associated estradiol was less than 50 ng/ml. In total, 225 patients were categorized into three groups: high FSH (FSH ≥10 IU/L; n= 36), normal FSH (>5 IU/L and <10 IU/L; n=170), and low FSH (FSH ≤5 IU/L; n= 19). ANOVA and multiple logistic regression were used for statistical comparisons and for evaluation of the relationships between variables; significance level was set at <0.05. Results: There were no significant differences in demographics, IVF cycle type, or peak estradiol level between the groups. Patients with a high basal FSH level had a similar clinical pregnancy rate and live birth rate compared to controls and patients with low FSH. High FSH level was associated with decreased follicular development (17 versus 22; p<0.01), oocyte yield (15 versus 18; p=0.02), and embryo yield (8 versus 10; p=0.04) despite higher total doses of gonadotropins. Conclusion: Patients with normal AMH and AFC levels could be further stratified into lower responders and starting doses of medications can be adjusted based on high basal FSH levels. Therefore, it is suggested to counsel patients on pregnancy outcomes which seem to be quite similar regardless of the FSH level.

Host immunity and KLF 11 deficiency together promote fibrosis in a mouse model of endometriosis.

BACKGROUND: Endometriosis is a debilitating disease typically characterized by prolific fibrotic scarring. Earlier we reported downregulation of two transcription factors belonging TGF-ßR signaling pathway Sp/Krüppel-like factor 11 (KLF11) and 10 (KLF10) in human endometriosis lesions. Here we investigated the role of these nuclear factors and immunity in the scaring fibrosis associated with endometriosis. METHODS: We used a well characterized experimental mouse model of endometriosis. WT, KLF10 or KLF11 deficient mice were compared. The lesions were evaluated histologically, fibrosis was quantified with Masons' Trichome staining, immune-infiltrates were quantified by immunohistochemistry, peritoneal adhesions were score, gene expression was evaluated by bulk RNA sequencing. RESULTS: Intense fibrotic reactions and large changes in gene expression were detected in KLF11 deficient implants associated with squamous metaplasia of the ectopic endometrium, as compared to KLF10 deficient or WT implants. Fibrosis was mitigated with pharmacologic agents that blocked histone acetylation or TGF-ßR signaling or with genetic deficiency for SMAD3. The lesions were richly infiltrated with T-cells, regulatory T-cells, and innate immune cells. Fibrosis was exacerbated when implants expressed ectopic genes implicating autoimmunity as a major factor contributing to the scaring fibrosis. CONCLUSIONS: Our findings identify KLF11 and TGF-ßR signaling as cell intrinsic mechanisms and autoimmune responses as cell extrinsic mechanisms of scaring fibrosis in ectopic endometrium lesions. GENERAL SIGNIFICANCE: Immunological factors associated with inflammation and tissue repair drive scaring fibrosis in experimental endometriosis, providing the rationale for immune therapy of endometriosis.

Lavender Aromatherapy to Reduce Anxiety During Intrauterine Insemination: A Randomized Controlled Trial.

BACKGROUND: Infertility is a global public health issue. Therapies such as intrauterine insemination (IUI) are effective but may be associated with considerable anxiety. Preliminary data suggest that decreasing this anxiety might lead to improved outcomes. OBJECTIVE: To determine whether lavender aromatherapy (LA) reduces anxiety during an IUI procedure. METHODS: A randomized controlled trial of women undergoing IUI at a hospital-based fertility clinic. The intervention and comparison were the use of LA vs water. Measurements were the change in anxiety level during an IUI procedure, with secondary assessment of pain scores, patient satisfaction, and pregnancy rates. RESULTS: In total, 67 women were screened, and 62 women randomly assigned to either placebo (n = 31) or LA (n = 31). No differences were observed in baseline demographic characteristics or visual analog scores for anxiety before IUI (mean [95% CI], 33.9 [25.2 to 45.6] mm vs 41.0 [33.0 to 49.0] mm) in the LA and placebo groups. However, a statistically significant change in anxiety was observed after LA inhalation during the procedure (mean [95% CI], -11.2 [-19.1 to -3.2]) compared with placebo (mean [95% CI], 1.3 [-5.6 to 8.2]; P = .02). No significant difference was observed in pain during IUI in the LA group vs placebo group. Patient satisfaction was high, with 93% of respondents in the LA group satisfied with the aromatherapy during their procedure. Additionally, 76% of participants who received placebo reported that they would prefer to use LA during their IUI. No statistically significant difference was detected in pregnancy rates between the 2 groups: 19.4% with LA vs 9.7% with placebo (P = .47). CONCLUSION: LA reduced anxiety and was preferred by women during IUI fertility treatments.

Is there still a role for a cleavage-stage embryo transfer?

OBJECTIVE: To determine whether pregnancy outcomes are poor or futile when an intended day 5 transfer is converted to a cleavage-stage transfer because of poor embryo development or a lower number of embryos. DESIGN: Retrospective cohort study. SETTING: Academic medical center. PATIENTS: Women with a limited number of embryos, defined as ≤6 two pronuclear embryos, after in vitro fertilization. INTERVENTIONS: Patients who had a cleavage-stage transfer were age matched with patients who had a day 5 transfer. MAIN OUTCOME MEASURES: Live birth rate. RESULTS: A total of 146 women were included in the study with 73 women in each group. Cleavage-stage transfer was associated with significantly lower implantation and clinical pregnancy rates compared with those of day 5 transfer. Although the live birth rate of the cleavage-stage transfer group was lower than that of the day 5 transfer group (25% vs. 40%, respectively), the cleavage-stage transfer still resulted in a live birth rate of 25%. A subanalysis comparing women who did and did not achieve live birth after cleavage-stage transfer demonstrated a live birth rate of 27% when at least one grade A embryo was transferred vs. 17% when a lesser quality embryo (grade B or C) was transferred. CONCLUSIONS: As expected, the live birth rate after cleavage-stage transfer was lower than that after day 5 transfer. However, the live birth rate of cleavage-stage transfer still fell into acceptable practice, >5%, for patients who were otherwise at very high risk of having no day 5 embryo transfer. Extended culture may not be necessary for all patients.

MRI impacts endometriosis management in the setting of image-based multidisciplinary conference: a retrospective analysis.

PURPOSE: The aim of the study was to quantify the value of pre-operative magnetic resonance imaging (MRI) in guiding surgical management of women with endometriosis. METHODS: Pre-operative discussion of patient management and review of imaging occurred for 136 patients with endometriosis in an MRI-based multidisciplinary conference co-directed by an abdominal radiologist and gynecologic surgeon. A tri-compartmental report template guided the systematic imaging review. Management changes made as a result of the conference were identified via retrospective chart review and classified as major, directly influencing the surgical procedure or approach, or minor, impacting the patient's medical management, therapies, or diagnostic evaluation. RESULTS: Of the 136 patients discussed in conference, a management change was identified in 18.4% (25 patients). Major changes occurred in 8.1% (11 patients) and minor changes in 13.2% (18 patients). The sum of major and minor management changes exceeded the total, as both major and minor management changes were made for 4 patients. CONCLUSION: Our findings demonstrate the ability of an MRI-based multidisciplinary conference to result in pre-operative management changes in approximately 1 of 5 pre-operatively reviewed women with endometriosis. Importantly, systematic review of the MRI facilitated management changes beyond that of the dictated report alone, which was available to clinicians prior to the conference. The study reflects the value of multidisciplinary interaction, with radiologists serving more directly as clinical consultants to surgical services, and suggests an opportunity to optimize the role of MRI in endometriosis management with standardized reports emphasizing surgically pertinent findings.

Association between kissing and retropositioned ovaries and severity of endometriosis: MR imaging evaluation.

PURPOSE: To retrospectively investigate the relationship between ovarian positioning on pre-operative MR imaging and intra-operative staging of endometriosis. MATERIALS AND METHODS: Sixty-five women with suspected endometriosis who underwent pre-operative MRI and subsequent intra-operative staging of endometriosis formed the study group. A trained senior radiology resident and a board-certified staff radiologist experienced in endometriosis reviewed MR images for ovarian positioning and the presence of an endometrioma. The position of the ovaries was classified as (a) kissing when they were posterior to the uterus and in contact, (b) retropositioned when they were posterior to the uterus but not in contact, or (c) normal. Intra-operative staging of endometriosis (stage 0 to IV) was determined using the revised American Society for Reproductive Medicine classification system (rASRM) by a surgeon with expertise in endometriosis surgery. Correlation between ovarian positioning and endometriosis stage was evaluated with a logistical regression analysis. Sensitivity, specificity, and accuracy were calculated. RESULTS: MR images revealed kissing ovaries in 12 women, retropositioned ovaries in 17 women, and normally positioned ovaries in 36 women. At surgery, endometriosis stages 0, I, II, III, and IV were found in 13, 15, 6, 9, and 22 patients, respectively. The odds of stage IV endometriosis were eight times higher given kissing or retropositioned compared to normal ovaries, regardless of the presence of an endometrioma (p =0.01). Kissing and retropositioned ovaries had an accuracy of 82% for stage IV endometriosis, with 86% sensitivity and 79% specificity. All cases with kissing ovaries had stage III/IV endometriosis. CONCLUSIONS: Kissing and retropositioned ovaries on pre-operative MR images are associated with higher intra-operative rASRM stages of endometriosis.

Clomiphene Stair-Step Protocol for Women With Polycystic Ovary Syndrome.

OBJECTIVE: To compare time to ovulation, ovulation rates, and side effect profile of traditional and the stair-step protocol for ovulation induction using clomiphene citrate in women with polycystic ovary syndrome (PCOS). METHODS: We performed a retrospective study of women seeking care for infertility with a diagnosis of PCOS at a university-based infertility clinic from July 2012 to July 2014. We included patients who were resistant to the initial starting dose of 50 mg clomiphene. The primary outcome was time to ovulation. Secondary outcomes included ovulation rates, clinical pregnancy rates, and mild and moderate-to-severe side effects based on dose. For the traditional protocol, higher doses of clomiphene were used each subsequent month if no ovulation occurred. For the stair-step protocol, higher doses of clomiphene were given 7 days after the last dose if no dominant follicles were seen on ultrasonography. Our study had 80% power to detect a 20% difference in ovulation. RESULTS: One hundred nine patients were included in the analysis with 66 (60.6%) in the traditional and 43 (39.4%) in the stair-step protocol. Age and body mass index were similar between groups. The time to ovulation was decreased in the stair-step protocol group compared with the traditional protocol group (23.1±0.9 days vs 47.5±6.3 days). Ovulation rates were increased in the stair-step group compared with the traditional group at 150 mg (16 [37%] vs 8 [12%], P=.004) and at 200 mg (9 [21%] vs 3 [5%], P=.01). Pregnancy rates were similar between groups once ovulation was achieved (12 [18.1%] vs 7 [16.3%], P=.08). The stair-step protocol had an increased incidence of mild side effects (vasomotor flushes, headaches, gastrointestinal disturbance, mastalgia, changes in mood; 18 [41%] vs 8 [12%]), but there was no difference in the incidence of severe side effects (headaches, visual disturbances). CONCLUSION: For women with PCOS, the stair-step clomiphene protocol is associated with decreased time to ovulation and increased ovulation rates at higher doses when compared with the traditional protocol.

Epigenetic Therapy: Novel Translational Implications for Arrest of Environmental Dioxin-Induced Disease in Females.

Increased toxicant exposure and resultant environmentally induced diseases are a tradeoff of industrial productivity. Dioxin [2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD)], a ubiquitous byproduct, is associated with a spectrum of diseases including endometriosis, a common, chronic disease in women. TCDD activates cytochrome (CYP) p450 metabolic enzymes that alter organ function to cause disease. In contrast, the transcription factor, Krüppel-like factor (KLF) 11, represses these enzymes via epigenetic mechanisms. In this study, we characterized these opposing mechanisms in vitro and in vivo as well as determining potential translational implications of epigenetic inhibitor therapy. KLF11 antagonized TCDD-mediated activation of CYP3A4 gene expression and function in endometrial cells. The repression was pharmacologically replicated by selective use of an epigenetic histone acetyltransferase inhibitor (HATI). We further showed phenotypic relevance of this mechanism using an animal model for endometriosis. Fibrotic extent in TCDD-exposed wild-type animals was similar to that previously observed in Klf11-/- animals. When TCDD-exposed animals were treated with a HATI, Cyp3 messenger RNA levels and protein expression decreased along with disease progression. Fibrotic progression is ubiquitous in environmentally induced chronic, untreatable diseases; this report shows that relentless disease progression can be arrested through targeted epigenetic modulation of protective mechanisms.

Progressive Fibrosis: A Progesterone- and KLF11-Mediated Sexually Dimorphic Female Response.

Progressive scarring is ubiquitous postoperatively and in an array of chronic systemic diseases. Recent studies indicate that such scarring has a high female propensity; females are also almost exclusively affected by endometriosis, a common sex steroid-dependent fibrotic disease. Endometriosis-related fibrosis is regulated epigenetically through transcription factor Krüppel-like factor 11 (KLF11). In response to surgical induction of endometriosis, Klf11-/- female mice develop significant fibrosis in contrast to wild-type mice. We therefore hypothesized that female fibrotic predilection was mediated by differential sex steroid regulation of KLF11/collagen 1a1 signaling and investigated the fibrotic response in wild-type and Klf11-/- male and female animals using a sterile peritonitis model. Fibrosis selectively developed in Klf11-/- females. Fibrosis in these animals was almost completely abrogated by ovariectomy. Ovariectomized animals were selectively supplemented with estradiol, medroxyprogesterone acetate (MPA), or dihydrotestosterone; fibrosis was only observed in mice exposed to MPA. Fibrosis therefore selectively developed in Klf11-/- female mice in response to physiological or pharmacological progesterone. The fibrotic response in these animals was also mitigated in response to antiprogestin therapy. Profibrotic gene expression was activated in a primary human peritoneal cell line in response to KLF11 short hairpin RNA and MPA but not estradiol. KLF11/collagen 1a1 signaling previously shown to be linked to fibrosis was thus selectively dysregulated in MPA-treated cells. Our in vivo and in vitro findings in an animal model and human cells, respectively, suggest that progressive fibrotic scarring is a sexually dimorphic response irrespective of etiology; moreover, it is responsive to novel, individualized therapeutic intervention.

KLF11 is an Epigenetic Mediator of DRD2/Dopaminergic Signaling in Endometriosis.

Endometriosis is a heterogeneous, recalcitrant disease that affects 10% of reproductive-age women. Resistance to conventional therapy critically raises the need for novel treatment options that target specific, dysregulated underlying molecular mechanisms. Dopamine receptor 2 (DRD2) has been shown to be associated with vascularity and fibrosis in endometriosis. Transcription factor KLF11 has been implicated in the pathogenesis of several human endocrine and reproductive tract diseases including endometriosis. KLF11 recruits epigenetic cofactors for regulation of target genes; dysregulation of critical target genes and associated signaling pathways results in diverse disease phenotypes. KLF11 regulates the expression of DRD2 in neurons. We investigated the regulation of DRD2 by KLF11 in the established eutopic and ectopic endometrial cell lines as well as in an animal model of endometriosis. KLF11 binding and activation of the DRD2 promoter was conserved across species. Promoter activation was reflected in correspondingly increased gene expression in an endometrial cell line and in primary endometriotic cells. In vivo, disease relevance was further evaluated in a surgically induced murine endometriotic model using Klf11-/- and wild-type mice. Consistent with loss of Klf11-mediated activation, lesions in Klf11-/- animals were associated with progressive fibrosis and decreased Drd2 expression. KLF11 binds specific epigenetic corepressors to repress several target genes. Activation of DRD2 by KLF11 could not be explained simply by loss of corepressor binding and is thus likely due to selective coactivator recruitment; identification of the precise pathway is the focus of ongoing investigation. Characterization of pharmacologically reversible epigenetic regulatory mechanisms has translational relevance in health and disease.

Daptomycin-oxacillin combinations in treatment of experimental endocarditis caused by daptomycin-nonsusceptible strains of methicillin-resistant Staphylococcus aureus with evolving oxacillin susceptibility (the "seesaw effect").

In vivo development of daptomycin resistance (DAPr) among Staphylococcus aureus strains, especially methicillin-resistant S. aureus (MRSA) strains, in conjunction with clinical treatment failures, has emerged as a major problem. This has raised the question of DAP-based combination regimens to enhance efficacy against such strains. We studied five recent DAP-susceptible (DAPs)/DAPr clinical MRSA strain pairs obtained from patients who failed DAP monotherapy regimens, as well as one DAPs/DAPr MRSA strain pair in which the resistant strain was generated by in vitro passage in DAP. Of note, we identified a DAP-oxacillin (OX) "seesaw" phenomenon in vitro in which development of DAPr was accompanied by a concomitant fall in OX resistance, as demonstrated by 3- to 4-fold decreases in the OX MIC, a susceptibility shift by population analyses, and enhanced early killing by OX in time-kill assays. In addition, the combination of DAP and OX exerted modest improvement in in vitro bactericidal effects. Using an experimental model of infective endocarditis and two DAPs/DAPr strain pairs, we demonstrated that (i) OX monotherapy was ineffective at clearing DAPr strains from any target tissue in this model (heart valve, kidneys, or spleen) and (ii) DAP-OX combination therapy was highly effective in DAPr strain clearances from these organs. The mechanism(s) of the seesaw effect remains to be defined but does not appear to involve excision of the staphylococcal cassette chromosome mec (SCCmec) that carries mecA.

Failures in clinical treatment of Staphylococcus aureus Infection with daptomycin are associated with alterations in surface charge, membrane phospholipid asymmetry, and drug binding.

Increasingly frequent reports have described the in vivo loss of daptomycin susceptibility in association with clinical treatment failures. The mechanism(s) of daptomycin resistance is not well understood. We studied an isogenic set of Staphylococcus aureus isolates from the bloodstream of a daptomycin-treated patient with recalcitrant endocarditis in which serial strains exhibited decreasing susceptibility to daptomycin. Since daptomycin is a membrane-targeting lipopeptide, we compared a number of membrane parameters in the initial blood isolate (parental) with those in subsequent daptomycin-resistant strains obtained during treatment. In comparison to the parental strain, resistant isolates demonstrated (i) enhanced membrane fluidity, (ii) increased translocation of the positively charged phospholipid lysyl-phosphotidylglycerol to the outer membrane leaflet, (iii) increased net positive surface charge (P < 0.05 versus the parental strain), (iv) reduced susceptibility to daptomycin-induced depolarization, permeabilization, and autolysis (P < 0.05 versus the parental strain), (v) significantly lower surface binding of daptomycin (P < 0.05 versus the parental strain), and (vi) increased cross-resistance to the cationic antimicrobial host defense peptides human neutrophil peptide 1 (hNP-1) and thrombin-induced platelet microbicidal protein 1 (tPMP-1). These data link distinct changes in membrane structure and function with in vivo development of daptomycin resistance in S. aureus. Moreover, the cross-resistance to hNP-1 and tPMP-1 may also impact the capacity of these daptomycin-resistant organisms to be cleared from sites of infection, particularly endovascular foci.

In vitro susceptibility of Staphylococcus aureus to thrombin-induced platelet microbicidal protein-1 (tPMP-1) is influenced by cell membrane phospholipid composition and asymmetry.

Thrombin-induced platelet microbicidal proteins (e.g. tPMP-1) are small cationic peptides released from mammalian platelets. As the cytoplasmic membrane (CM) is a primary target of tPMPs, distinct CM characteristics are likely to affect the cells' susceptibility profiles. In Staphylococcus aureus, CM surface charge and hydrophobicity are principally determined by the content and distribution of its three major phospholipid (PL) constituents: negatively charged phosphatidylglycerol (PG) and cardiolipin (CL) and positively charged lysyl-PG (LPG). PL composition profiles, and inner vs outer CM leaflet PL distributions, were compared in an isogenic tPMP-susceptible (tPMP(S)) and -resistant (tPMP(R)) S. aureus strain pair (ISP479C vs ISP479R respectively). All PLs were asymmetrically distributed between the outer and inner CM leaflets in both strains. However, in ISP479R, the outer CM leaflet content of LPG was significantly increased vs ISP479C (27.3+/-11.0 % vs 18.6+/-7.0 % respectively; P=0.05). This observation correlated with reduced binding of the cationic proteins cytochrome c, poly-L-lysine, tPMP-1 and the tPMP-1-mimetic peptide, RP1, to tPMP-1(R) whole cells and to model liposomal CMs with LPG content and distribution similar to that of tPMP-1(R) strains. Collectively, selected CM parameters correlated with reduced staphylocidal capacities of tPMP-1 against certain S. aureus strains, including relative increases in outer CM leaflet positive charge and reduced surface binding of cationic molecules. These findings offer new insights into mechanisms of antimicrobial peptide susceptibility and resistance in S. aureus.

Transposon disruption of the complex I NADH oxidoreductase gene (snoD) in Staphylococcus aureus is associated with reduced susceptibility to the microbicidal activity of thrombin-induced platelet microbicidal protein 1.

The cationic molecule thrombin-induced platelet microbicidal protein 1 (tPMP-1) exerts potent activity against Staphylococcus aureus. We previously reported that a Tn551 S. aureus transposon mutant, ISP479R, and two bacteriophage back-transductants, TxA and TxB, exhibit reduced in vitro susceptibility to tPMP-1 (tPMP-1(r)) compared to the parental strain, ISP479C (V. Dhawan, M. R. Yeaman, A. L. Cheung, E. Kim, P. M. Sullam, and A. S. Bayer, Infect. Immun. 65:3293-3299, 1997). In the current study, the genetic basis for tPMP-1(r) in these mutants was identified. GenBank homology searches using sequence corresponding to chromosomal DNA flanking Tn551 mutant strains showed that the fourth gene in the staphylococcal mnh operon (mnhABCDEFG) was insertionally inactivated. This operon was previously reported to encode a Na(+)/H(+) antiporter involved in pH tolerance and halotolerance. However, the capacity of ISP479R to grow at pH extremes and in high NaCl concentrations (1 to 3 M), coupled with its loss of transmembrane potential (DeltaPsi) during postexponential growth, suggested that the mnh gene products are not functioning as a secondary (i.e., passive) Na(+)/H(+) antiporter. Moreover, we identified protein homologies between mnhD and the nuo genes of Escherichia coli that encode components of a complex I NADH:ubiquinone oxidoreductase. Consistent with these data, exposures of tPMP-1-susceptible (tPMP-1(s)) parental strains (both clinical and laboratory derived) with either CCCP (a proton ionophore which collapses the proton motive force) or pieracidin A (a specific complex I enzyme inhibitor) significantly reduced tPMP-induced killing to levels seen in the tPMP-1(r) mutants. To reflect the energization of the gene products encoded by the mnh operon, we have renamed the locus sno (S. aureus nuo orthologue). These novel findings indicate that disruption of a complex I enzyme locus can confer reduced in vitro susceptibility to tPMP-1 in S. aureus.

Persistent bacteremia due to methicillin-resistant Staphylococcus aureus infection is associated with agr dysfunction and low-level in vitro resistance to thrombin-induced platelet microbicidal protein.

BACKGROUND: The causes of persistent bacteremia (PB) due to methicillin-resistant Staphylococcus aureus (MRSA) are poorly understood. This investigation examined potential associations between PB with key clinical features and several in vitro bacterial genotypic and phenotypic characteristics, in isolates from 1 institution. METHODS: Pulsed-field gel electrophoresis (PFGE) relatedness, thrombin-induced platelet microbicidal protein (tPMP)-susceptibility phenotype, accessory gene regulator (agr) genotype and functionality (via delta-lysin production), and autolysis phenotypes were assessed in MRSA isolates from the bloodstream of 21 prospectively identified patients with PB (blood cultures positive after > or =7 days of therapy) and of 18 patients with resolving bacteremia (RB) (sterile blood cultures within the first 2-4 days of therapy) due to MRSA. RESULTS: The 2 groups had comparable baseline characteristics but differed in their clinical courses (e.g., endocarditis was more frequent in patients with PB than in those with RB [43% vs. 0%, respectively; P=.0016]); isolates from patients with PB exhibited higher rates of (1) survival in vitro after exposure to tPMP (22.4+/-14.8% vs. 11.6+/-6.5%, respectively; P=.005); (2) defective delta-lysin production (71.4% vs. 38.9%, respectively; P=.057); (3) non-agr genotype II profile (100% vs. 77.8%, respectively; P=.037); and (4) overrepresentation of a specific PFGE genotype (85.7% vs. 44.4%, respectively; P=.015). CONCLUSIONS: Isolates from patients with PB differed from those in patients with RB, in several in vitro characteristics. Further studies will be necessary to define how these factors might affect clinical outcome.