Urogenital Flora

7 Key excerpts on "Urogenital Flora"

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  eBook - ePub

  The Human Microbiota

  How Microbial Communities Affect Health and Disease

  • David N. Fredricks(Author)
  • 2013(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Lactobacillus species tend to dominate the vaginal bacterial community in women worldwide. Bacterial vaginosis remains a poorly understood condition associated with increased risks to a woman’s health. However, the clinical diagnostics that define this condition are becoming outdated in the molecular era and their limitations increasingly apparent. Here we have described the latest epidemiological and ecological findings regarding the vaginal microbiota firmly in the context of the current gold standard diagnostic for BV, the Nugent score, as this remains the best tool we have for peering across studies and drawing the most generalizable conclusions. However, we also noted the fact that Nugent score can be an imperfect descriptor of what is happening with the microbiota. As sequencing costs continue to drop and methods for comparing and classifying microbial communities are improved and standardized, bacterial metagenomics will undoubtedly yield a variety of risk assessment tools for BV and its sequelae. What we do know today is that many of the bacterial species found in women with BV are novel, and although a number remain uncultivated, studies using molecular detection methods are linking them to troublesome symptoms of odorous vaginal discharge and adverse health outcomes such as preterm birth and HIV shedding. Although many challenging questions remain, particularly with regard to the dynamic fluctuations of the vaginal microbiota, the significance of urogenital microbes in niches other than the vagina, and the mechanisms by which these complex communities interact with the host, progress in these areas may have high payoff. Someday, with the ability to profile human genitourinary microbes and medically manipulate them to prevent disease, help produce a healthy full-term baby, or perhaps even improve a woman’s sex life after menopause, today’s blissful ignorance of the genitourinary microbiota may very well be replaced by informed empowerment.

  References

  1. Aboul Enien WM, El Metwally HA. Association of abnormal vaginal flora with increased cervical tumour necrosis factor—alpha and interferon—gamma levels in idiopathic infertility. Egypt J Immunol 12:53–59 (2005).

  2. Al-Mushrif S, Jones BM. A study of the prevalence of hydrogen peroxide generating Lactobacilli in bacterial vaginosis: The determination of H2O2 concentrations generated, in vitro , by isolated strains and the levels found in vaginal secretions of women with and without infection. J Obstet Gynaecol 18:63–67 (1998).

  3. Alakomi HL, Skytta E, Saarela M, Mattila-Sandholm T, Latva-Kala K, Helander IM. Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane. Appl Environ Microbiol 66:2001–2005 (2000).

  4. Amsel R, Totten PA, Spiegel CA, Chen KC, Eschenbach D, Holmes KK. Nonspecific vaginitis. Diagnostic criteria and microbial and epidemiologic associations. Am J Med 74:14–22 (1983).

  5. Ansbacher R, Boyson WA, Morris JA. Sterility of the uterine cavity. Am J Obstet Gynecol 77:394–396 (1967).

  6. Antonio MA, Hawes SE, Hillier SL. The identification of vaginal Lactobacillus species and the demographic and microbiologic characteristics of women colonized by these species. J Infect Dis 180:1950–1956 (1999).

  7. Antonio MA, Meyn LA, Murray PJ, Busse B, Hillier SL. Vaginal colonization by probiotic Lactobacillus crispatus CTV-05 is decreased by sexual activity and endogenous Lactobacilli. J Infect Dis

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  Human Microbiota and Microbiome, The

  • Julian Marchesi, Julian R Marchesi(Authors)
  • 2014(Publication Date)
  • CAB International

    (Publisher)

  et al ., 2005) have led to renewed interest in the male urogenital tract micro biome and its potential roles.

  3.3.1 The many potential microbiomes of the penis

  Cells on the surface of the penile shaft, foreskin, glans and those lining the urethra are in close proximity to one another, but the microbial communities that they support differ significantly (discussed below). The squamous epithelium of the penile shaft is heavily keratinized and is impermeable to moisture (Anderson et al ., 2011; Pudney and Anderson, 2011). In contrast, cells of the foreskin, at the juncture of the penile shaft and glans (coronal sulcus), and on the surface of the underlying glans and extending through the urethral meatus into the fossa navicularis are more lightly keratinized epithelium with features intermediate between skin and mucosa (Anderson et al ., 2011; Pudney and Anderson, 2011). Male circumcision involves the surgical removal of the foreskin (prepuce), which destroys most of the preputial space, reduces moisture of the coronal sulcus (CS) and glans (O’Farrell et al ., 2006) and promotes keratinization of the glans (de Vincenzi and Mertens, 1994). In contrast, the urethra proper, extending from the proximal end of the fossa navicularis to the prostate gland, is perpetually moist, is covered in columnar epithelial cells and glands that secrete mucins and bacteriocins into the urethral lumen and shares many immunological features with other mucosal surfaces (Anderson et al ., 2011; Pudney and Anderson, 2011). The idea that the penis could support multiple independent microbiomes is also supported by observations that some sexually transmitted pathogens preferentially target distinct regions of the penis. For example, Haemophilus ducreyi , human papilloma viruses, and herpes simplex virus 2 commonly infect the penile epithelium, whereas the intracellular pathogen, Chlamydia trachomatis , strictly targets urethral columnar epithelial cells (Nelson et al

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  Microbiology

  Principles and Explorations

  • Jacquelyn G. Black, Laura J. Black(Authors)
  • 2018(Publication Date)
  • Wiley

    (Publisher)

  Components of the Urogenital System 583 Defense mechanisms in the urogenital system are numerous. Normal microflora compete with opportunists and pathogens for nutrients and space and prevent them from causing disease. Urinary sphincters (muscles that close openings) act as mechanical barriers to microbes and also help prevent the backflow of urine. The flow of urine through the urethra and of mucus through both the urethra and vagina helps wash away microbes. The low pH within both the urethra and, during reproductive years, the vagina prevents invasion by pathogens. Semen contains lysozyme and spermine, which help destroy in- vading pathogens. Despite its defenses, the urogenital tract is poorly protected against sexually transmitted diseases. The or- ganisms that cause gonorrhea, syphilis, and nongonocco- cal urethritis tolerate acidic conditions and successfully compete with natural microflora of the urogenital tract. Normal Microbiota of the Urogenital System In healthy individuals all parts of the urinary tract, ex- cept the portion of the urethra closest to the urethral opening, are sterile. This colonization of the urethral end ensures that even “clean catch” urine specimens will con- tain bacteria flushed out of the urethra during voiding. Escherichia coli and Lactobacillus are the most common organisms, and can reach 100,000 bacteria/ml of urine. However, if urine is collected by direct puncture (supra- pubic) of the bladder with sterile needle and syringe, the urine is typically sterile in a healthy person. Acid pH and high salt and urea concentrations retard the growth of bacteria in urine. However, urine specimens should be delivered to the lab promptly and refrigerat- ed during any delays, as microbes will multiply rapidly in urine left sitting out at room temperature. When this infectious diseases of the urogenital system are sexually transmitted, in- cluding genital herpes, gonorrhea, syphilis, and nongonoccocal urethri- tis.

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  Infectious Diseases of the Dog and Cat

  • Jane E. Sykes, Craig E. Greene(Authors)
  • 2011(Publication Date)
  • Saunders

    (Publisher)

  Chapter 90

  Genitourinary Infections

  Jeanne A. Barsanti

  Bacterial infections of the urogenital system are among the most frequently encountered infections in small animal practice. Urinary tract and genital infections can occur separately or concomitantly. Infections range in severity from asymptomatic to life threatening. Escherichia coli is the most common agent associated with these infections. Infections with other types of organisms, especially fungi, are found but are much rarer than those caused by bacteria.

  Resident Microflora

  The vagina, vestibule, prepuce, and distal urethra have a resident microflora. The oral and anal flora of neonatal puppies correlate with the flora from the milk, vagina, and oral cavity of their dams. The flora of puppies from different dams varies with the dam.273 Bacteria are not normally found in the upper urinary tract, bladder, proximal urethra, or prostate gland.

  23 ,170

  Bacteria are not normally found in the uterus, except during proestrus and estrus.

  71 ,93 ,406

  The clinical importance of the microflora is twofold: first, it must be considered when the results of cultures of urine, semen, and preputial and vulvar discharges are interpreted; second, the normal microflora is thought to be an important factor in host defense against pathogenic organisms. The resident microflora competes with pathogenic bacteria for nutrients and can interfere with adherence of pathogenic bacteria to vaginal epithelial receptors. Lactobacilli isolated from the vagina of dogs showed antimicrobial activity against Proteus mirabilis, Staphylococcus aureus, and Escherichia coli .91

  Dogs

  In clinically healthy male dogs, commensal bacteria cultured from the distal urethra and prepuce include gram-positive and gram-negative organisms (Boxes 90-1 and 90-2 ).22 Mycoplasmas are found in the distal urethra and the prepuce and have also been isolated from the canine prostate. When sampling the prepuce, usually more than one organism is recovered; however, only a single species is obtained in about 20% of preputial and semen samples.48 The prostatic fraction of a cleanly collected ejaculate from healthy, fertile stud dogs is usually sterile (70% of samples).48

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  The Scientific Basis of Urology

  • Anthony R. Mundy, John Fitzpatrick, David E. Neal, Nicholas J. R. George, Anthony R. Mundy, John Fitzpatrick, David E. Neal, Nicholas J. R. George(Authors)
  • 2010(Publication Date)
  • CRC Press

    (Publisher)

  9 Urinary Tract Infection Nicholas J. R. George Department of Urology, Withington Hospital, University Hospitals of South Manchester, Manchester, U.K. INTRODUCTION The infectious process encompasses a highly complex series of events that surround the relationship between the defending host and the offending para-site. Virulence factors available to the microorganism will be combated by a wide range of specific and nonspecific defense mechanisms, and the result of this encounter, ‘‘the microbiological battleground,’’ will determine whether infectious disease is established. Conventionally, accounts of infection of the uri-nary tract concentrate on the response of the urothe-lium to bacterial invasion. However, a continuing and perhaps increasing tendency to open surgery in cer-tain groups of patients determines that a basic under-standing of the broader concepts of the infectious process is likely to be advantageous for the practicing urological surgeon. Therefore, in this account of uri-nary tract infection (UTI), before dealing with specific issues relating to organisms and the urothelium, a general description will be made of the host-parasite relationship as it applies to the urogenital system both in health and disease. Some important fundamental definitions are noted in Table 1. Such general micro-biological points may be considered under the follow-ing headings. 1. Colonizing microorganisms in health 2. General defense mechanisms 3. General modifying factors 4. Properties of commensal organisms Colonizing Microorganisms in Health Table 2 lists common colonizing microorganisms by site in healthy humans. The widespread presence of staphylococci and streptococci on the skin and surrounding the lower genitourinary tract will be appreciated, as will the occurrence of Candida and lactobacilli within vaginal flora. The colon contains enormous numbers of bacteria—up to 10 11 organisms per gram.

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  Microbiology

  • Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Brian M. Forster, Philip Lister(Authors)
  • 2016(Publication Date)
  • Openstax

    (Publisher)

  Chapter 23 Urogenital System Infections Figure 23.1 Many pathogens that cause infections of the urogenital system can be detected in urine samples (left). The top sample in the culture (right) was prepared from the urine of a patient with a urinary tract infection. (credit b: modification of work by Nathan Reading) Chapter Outline 23.1 Anatomy and Normal Microbiota of the Urogenital Tract 23.2 Bacterial Infections of the Urinary System 23.3 Bacterial Infections of the Reproductive System 23.4 Viral Infections of the Reproductive System 23.5 Fungal Infections of the Reproductive System 23.6 Protozoan Infections of the Urogenital System Introduction The urogenital system is a combination of the urinary tract and reproductive system. Because both systems are open to the external environment, they are prone to infections. Some infections are introduced from outside, whereas others result from imbalances in the microbiota of the urogenital tract. Urinary tract infections (UTIs) are one the most common bacterial infections worldwide, affecting over 100 million people each year. During 2007 in the United States, doctor office visits for UTIs exceeded 10 million, and an additional 2–3 million emergency department visits were attributed to UTIs. Sexually transmitted infections (STIs) also primarily affect the urogenital system and are an important cause of patient morbidity. The Centers for Disease Control and Prevention (CDC) estimates that there are approximately 20 million new cases of reportable STIs annually in the United States, half of which occur in people aged 15–24 years old. When STIs spread to the reproductive organs, they can be associated with severe morbidity and loss of fertility. Because males and females have different urogenital anatomy, urogenital infections may affect males and females differently. In this chapter, we will discuss the various microbes that cause urogenital disease and the factors that contribute to their pathogenicity.

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  Visualizing Microbiology

  • Rodney P. Anderson, Linda Young(Authors)
  • 2016(Publication Date)
  • Wiley

    (Publisher)

  Lactobacillus colonization of the vagina effectively eliminates many potential pathogens introduced by sexual contact, some well-adapted microorganisms still flourish, causing infection. Also, the biological defenses of the reproductive system can be disrupted by antibiotic use, which rapidly alters vaginal conditions, allowing the growth of pathogens that are normally suppressed.

  The vertical transmission of infection from mother to child is exclusive to the reproductive system. Some pathogens cross the placenta, initiating infection of the fetus, and vaginal microbes can inoculate the neonate during delivery.

  Normal Microbiota

  The composition of vaginal microbiota (Table 21.1 ) evolves throughout a woman's lifetime and, to a lesser extent, fluctuates with her menstrual cycle to maximize its protective value.

  Location in the urogenital system	Microbial species
  Anterior urethra	Acinetobacter spp., Candida albicans, Corynebacterium spp., Enterobacteriaceae, Streptococcus viridans
  Cervix	Mycoplasma hominis, Streptococcus agalactiae
  External genitalia	Bacteroides spp., Corynebacterium spp., Enterobacteriaceae, Streptococcus viridans
  General distribution	Eikenella corrodens, Streptococcus anginosus
  Perineum	Staphylococcus aureus
  Urethra	Chlamydia spp.
  Vagina	Bifidobacterium spp., Candida albicans, Chlamydia spp., Clostridium spp., Corynebacterium spp., Enterobacteriaceae, Gardnerella vaginalis, Lactobacillus spp., Mobiluncus curtisii, Mobiluncus mulieris, Mycoplasma hominis, Streptococcus agalactiae, Streptococcus viridans

  Normal microbiota of the female reproductive system Table 21.1

  If the levels of Lactobacillus in a healthy vaginal microbial community decline, the corresponding reduction in hydrogen peroxide and acid production triggers an increase in vaginal pH. Under these new conditions, Gardnerella vaginalis and Mobiluncus spp. grow rapidly, upsetting the balance of the vaginal microbial community and leading to

  bacterial vaginosis (BV)

  . Although some women demonstrate no symptoms, most patients experience a thin, gray vaginal discharge with a strong fishy odor, burning during urination, and vaginal itching. BV is easily diagnosed by the presence of

  clue cells

  in a Gram-stained specimen collected by a gynecologist (Figure 21.2a

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