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In a prospective study, Craig Cohen and colleagues investigate the association between bacterial vaginosis and the risk of female-to-male HIV-1 transmission.

The most common form of oral candidiasis, denture-associated stomatitis, involves biofilm growth on an oral prosthetic surface. Cells in this unique environment are equipped to withstand host defenses and survive antifungal therapy. Studies of the biofilm process on dentures have primarily been limited to in vitro models. We developed a rodent acrylic denture model and characterized the Candida albicans and mixed oral bacterial flora biofilm formation, architecture, and drug resistance in vivo, using time course quantitative culture experiments, confocal microscopy, scanning electron microscopy, and antifungal susceptibility assays. We also examined the utility of the model for measurement of C. albicans gene expression and tested the impact of a specific gene product (Bcr1p) on biofilm formation. Finally, we assessed the mucosal host response to the denture biofilm and found the mucosal histopathology to be consistent with that of acute human denture stomatitis, demonstrating fungal invasion and neutrophil infiltration. This current oral denture model mimics human denture stomatitis and should be useful for testing the impact of gene disruption on biofilm formation, studying the impact of anti-infectives, examining the biology of mixed Candida-oral bacterial flora biofilm infections, and characterizing the host immunologic response to this disease process.

To study the cause of nonspecific vaginitis, we analyzed vaginal fluid from normal women and from 53 women with nonspecific vaginitis, using quantitative anaerobic cultures and gas-liquid chromatography for short-chained organic-acid metabolites of the microbial flora. In normal vaginal fluid, lactate was the predominant acid, and the predominant organisms were lactobacillus and streptococcus species (lactate producers). In nonspecific vaginitis, lactate was decreased, whereas succinate, acetate, butyrate, and propionate were increased, the predominant flora included Gardnerella (Haemophilus) vaginalis (acetate producer), and anaerobes, which included bacteroides species (succinate producers) and peptococcus species (butyrate and acetate producers). After metronidazole therapy, symptoms and signs of nonspecific vaginitis cleared, butyrate and propionate disappeared, and lactate and lactate-producing organisms became predominant. We conclude that certain anaerobes act with G. vaginalis as causes of nonspecific vaginitis, and that a high ratio of succinate to lactate in vaginal fluid is a useful indicator in the diagnosis of this condition.

enterococcal blood isolates at the University of Wisconsin Hospital and Clinics were analyzed for high-level aminoglycoside resistance (hereafter high-level aminoglycoside resistance is simply referred to as "resistance") and hemolysin production. Of 190 Enterococcusfaecalis isolates, 68 (35.8%) were resistant to gentamicin. Of these 68 strains, 67 (98.5%) contained a gene coding for the bifunctional oglycoside-mofying 6'-aminoglycoside acetltransferase-2-m glycoside phosphotransferase [AAC(6')-APH(2")J enzyme. Of 190 isolates, 85 (44.7%) were hemolytic and contained a gene coding for component A of the enterococcal hemolysin. Sixty-two of 68 (91.2%) gentam resistant isolates but only 23 of 122 (18.8%) gentamicin-susceptible isolates were hemolytic (P < 0.001). Twelve of the hemolytic, gentamicin-resistant E. faecalis blood isolates, but only 2 of 9 nonhemolytic or gentamicinsusceptible isolates, had identical chromosomal DNA restriction endonuclease digestion patterns, suggesting a common derivation for these strains. A historical cohort study from 1 Enterococci are the third leading cause of nosocomial infection and the sixth leading cause of hospital-acquired bacteremia in the United States (9). Numerous studies report 30 to 68% case/fatality ratios for patients with enterococcal bacteremia (3, 7, 13, 16, 21, 32, 35-37, 40, 50, 54, 66). Although preexisting debilitating conditions and concomitant infections contributed to high overall mortality rates in these studies, death was attributed directly to enterococcal sepsis in 7 to 50% of fatal cases (7,35,37,50,54,64). Similarly, an analysis of 500 bloodstream infections at the University of Colorado Hospital identified enterococci as the only gram-positive organism independently associated with a high risk of death (63). Yet, despite the poor prognosis associated with nosocomial enterococcal bacteremia, little is known of microbial determinants that contribute to adverse outcomes.Antibiotic resistance (22,45) or hemolysin production (27) by enterococci might interfere with adequate treatment of deep-seated enterococcal infections. Enterococcal infection caused by strains with high-level resistance to gentamicin (MIC > 2 mg/ml) (hereafter high-level aminoglycoside resistance is simply referred to as "resistance") has been reported (2,22,48,60,68,69). Factors predisposing patients to the acquisition of resistant enterococci include hospitalization longer than 2 weeks (2), receipt of multiple antibiotics (2) including cephalosporins or aminoglycosides (68), and

Bacterial vaginosis (BV) is the most common of the vaginitides affecting women of reproductive age. It appears to be due to an alteration in the vaginal ecology by which Lactobacillus spp., the predominant organisms in the healthy vagina, are replaced by a mixed flora including Prevotella bivia, Prevotella disiens, Porphyromonas spp., Mobiluncus spp., and Peptostreptococcus spp. All of these organisms except Mobiluncus spp. are also members of the endogenous vaginal flora. While evidence from treatment trials does not support the notion that BV is sexually transmitted, recent studies have shown an increased risk associated with multiple sexual partners. It has also been suggested that the pathogenesis of BV may be similar to that of urinary tract infections, with the rectum serving as a reservoir for some BV-associated flora. The organisms associated with BV have also been recognized as agents of female upper genital tract infection, including pelvic inflammatory disease, and the syndrome BV has been associated with adverse outcome of pregnancy, including premature rupture of membranes, chorioamnionitis, and fetal loss; postpartum endometritis; cuff cellulitis; and urinary tract infections. The mechanisms by which the BV-associated flora causes the signs of BV are not well understood, but a role for H2O2-producing Lactobacillus spp. in protecting against colonization by catalase-negative anaerobic bacteria has been recognized. These and other aspects of BV are reviewed.

To determine whether bacterial vaginosis (BV), also known as nonspecific vaginitis, could be diagnosed by evaluating a Gram stain of vaginal fluid, we examined samples from 60 women of whom 25 had clinical evidence of BV and 35 had candidal vaginitis or normal examinations. An inverse relationship between the quantity of the Lactobacillus morphotype (large gram-positive rods) and of the Gardnerella morphotype (small gram-variable rods) was noted on Gram stain (P < 0.001). When Gram stain showed a predominance (3 to 4+) of the Lactobacillus morphotype with or without the Gardnerella morphotype, it was interpreted as normal. When Gram stain showed mixed flora consisting of gram-positive, gramnegative, or gram-variable bacteria and the Lactobacillus morphotype was decreased or absent (0 to 2+), the Gram stain was interpreted as consistent with BV. Gram stain was consistent with BV in 25 of 25 women given a clinical diagnosis of BV and in none of 35 women with candidal vaginitis or normal examinations. Duplicate slides prepared from 20 additional specimens of vaginal fluid were stained by two methods and examined by three evaluators. Interevaluator interpretations and intraevaluator interpretations of duplicate slides were in agreement with one another and with the clinical diagnosis .90% of the time. We concluded that a microscopically detectable change in vaginal microflora from the Lactobacillus morphotype, with or without the Gardnerella morphotype (normal), to a mixed flora with few or no Lactobacillus morphotypes (BV) can be used in the diagnosis of BV.

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