Update on Vaginal Infections
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PROGRESOS DE Obstetricia y Revista Oficial de la Sociedad Española Ginecología de Ginecología y Obstetricia Revista Oficial de la Sociedad Española de Ginecología y Obstetricia Prog Obstet Ginecol 2019;62(1):72-78 Revisión de Conjunto Update on vaginal infections: Aerobic vaginitis and other vaginal abnormalities Actualización en infecciones vaginales: vaginitis aeróbica y otras alteraciones vaginales Gloria Martín Saco, Juan M. García-Lechuz Moya Servicio de Microbiología. HGU Miguel Servet. Zaragoza Abstract It is estimated that abnormal vaginal discharge cannot be attributed to a clear infectious etiology in 15% to 50% of cases. Some women develop chronic vulvovaginal problems that are difficult to diagnose and treat, even by specialists. These disorders (aerobic vaginitis, desquamative inflammatory vaginitis, atrophic vaginitis, and cytolytic vaginosis) pose real challenges for clinical diagnosis and treatment. Researchers have established Key words: a diagnostic score based on phase-contrast microscopy. We review reported evidence on these entities and Vaginitis. present our diagnostic experience based on the correlation with Gram stain. We recommend treatment with Aerobic vaginitis. an antibiotic that has a very low minimum inhibitory concentration against lactobacilli and is effective against Parabasal cells. enterobacteria and Gram-positive cocci, which are responsible for these entities (aerobic vaginitis and desqua- Diagnosis. mative inflammatory vaginitis). Resumen Se estima que entre el 15 y el 50% de las mujeres que tienen trastornos del flujo vaginal, éstos no pueden atri- buirse a una etiología infecciosa clara. Algunas de ellas desarrollarán problemas vulvovaginales crónicos difíciles de diagnosticar y tratar, incluso por especialistas. Son trastornos que plantean desafíos reales en el diagnóstico Palabras clave: clínico y en su tratamiento como la vaginitis aeróbica, la vaginitis inflamatoria descamativa, la vaginitis atrófica y la vaginitis citolítica. Para diagnosticarlos, algunos investigadores han establecido una puntuación basada en la Vaginitis. Vaginitis aeróbica. observación microscópica mediante contraste de fases. En este artículo, se revisa la evidencia publicada sobre Microbiota estas entidades y presentamos nuestra experiencia en la correlación diagnóstica con la tinción de Gram. Se vaginal. Células recomienda el tratamiento con un antibiótico con una concentración mínima inhibitoria muy baja contra los lac- parabasales. tobacilos y eficaz contra las enterobacterias y los cocos grampositivos, responsables de estas entidades (vaginitis Diagnóstico. aeróbica y vaginitis inflamatoria descamativa). Correspondencia: Recibido: 04/03/2018 Gloria Martín Saco Aceptado: 18/09/2018 Servicio de Microbiología HGU Miguel Servet Martín Saco G, García-Lechuz Moya JM. Update on vaginal infections: Aerobic vaginitis Paseo Isabel la Católica, 1-3 and other vaginal abnormalities. Prog Obstet Ginecol 2019;62(1):72-78. DOI: 10.20960/j. 50009 Zaragoza pog.00172 e-mail: [email protected] UPDATE ON VAGINAL INFECTIONS: AEROBIC VAGINITIS AND OTHER VAGINAL ABNORMALITIES 73 INTRODUCTION frequently colonize the vagina in most cases are Lacto- bacillus iners (34%), Lactobacillus crispatus (27%), Lac- Vaginitis is the term used to define disorders of the tobacillus gasseri (6%), Lactobacillus jensenii (5%), and vagina caused by infection, inflammation, or changes in a mixed group including Gardnerella vaginalis (27%) (3). normal vaginal flora. Lactobacilli act by protecting the vagina from coloniza- Vaginal problems are one of the main reasons women tion by pathogens in 3 ways (Fig. 1): seek medical attention. It is estimated that no clear infec- 1. By inhibiting the growth of other pathogens via tious etiology can be assigned in 15% to 50% of women competition for the substrate. Lactobacilli do this by (1). Some women develop chronic vulvovaginal disorders producing hydrogen peroxide and organic acids and that are difficult to diagnose and treat, even for specia- metabolizing glycogen, which depends on the pro- lists (2). Therefore, based on the well-known and complex duction of estrogens and accumulates in the squa- vaginal ecosystem, we aim to provide a review of less well- mous epithelium and in lactic acid, thus leading to a known vaginal disorders that go beyond microbiological vaginal pH of ≤4.5. concepts and generate real challenges in clinical diagnosis 2. By inhibiting the adhesion of other microorganisms and treatment. These disorders include aerobic vaginitis, through adhesion to epithelial cells and the muco- desquamative inflammatory vaginitis, atrophic vaginitis, sa to produce surfactants and binding to vaginal and cytolytic vaginitis. fibronectin. 3. Blocking the spread of other pathogens by binding to them (coaggregation). Vaginal ecosystem However, the absence of lactobacilli does not inevita- bly mean that the patient will develop a disease, since The "healthy" vaginal ecosystem, in which Lactobaci- other bacteria also produce lactic acid and help maintain llus is the predominant microorganism, plays a key role a healthy medium in the vagina (4). Not all strains of Lac- in the determination and prevention of various genital tobacillus species express these properties with the same infections (including sexually transmitted infections intensity, and there are considerable differences between [STIs]) and urinary infections. The species that most species, and even between strains of the same species. Figure 1: a) Coaggregation; b) Production of biosurfactants; c) Production of bacteriocins and hydrogen peroxide; d) Regulation of toxin production; e) Competition for nutrients and surface receptors; f) Production of antimicrobial peptides (eg, defensins, lactoferrin, lysozyme, and alkaline phosphata- ses); g) On covering the surface of connections between cells, the lactobacilli prevent the penetration of other microorganisms. Adapted from Reference 5, Reid et al. Nature Rev Micro 2011. [Prog Obstet Ginecol 2019;62(1):72-78] 74 G. Martín Saco et al. The intensity of these properties has led some strains to teria (Lactobacillus species) and, in contrast, facilitate be used as probiotics (5). the presence of others (eg, enterobacteria, Staphylococ- Lactobacilli live together with several species of cus species, anaerobes). Hormonal changes in the pre- microorganism in the vagina. Most are anaerobic (aerobic menarche are sometimes sudden and facilitate massive microorganisms are more common, in a proportion of 10 colonization byLactobacillus species. This usually leads to to 1) (6). These microorganisms make up the microbiota considerable desquamation of cells, which is often asso- of the healthy vagina: ciated with abundant secretions, leading the patient to – Facultative anaerobes and aerobes: Gram-positive visit her doctor. Infections byCandida species are common bacilli (Lactobacillus species, 45%-88% of women; during this period. These represent the abovementioned Corynebacterium species, 14%-72%; Gardnerella changes (estrogens facilitate the expression of Candida vaginalis, 2%-58%); Gram-positive cocci Staphylo( - virulence factors) and the establishment of the microbiota coccus epidermidis, 34%-92%; Staphylococcus aureus, in adult women. During reproductive age, depending on 1%-32%; Group B Streptococcus 6%-22%; Entero- sexual activity and the regularity of the menstrual cycle, coccus species 32%-36%; nonhemolytic streptococ- the microbiota is made up mainly of lactobacilli and other ci, 14%-33%; α-hemolytic streptococci, 17%-36%); bacteria whose metabolic products enable pH to remain Gram-negative bacilli (Escherichia coli 20%-28%, below 4.5. and other Enterobacteriaceae in lower proportions); During the puerperium, in contrast with pregnancy, mollicutes (Mycoplasma hominis, 0%-22% and Urea- the vaginal microbiota undergoes dramatic changes, plasma urealyticum, 0%-58%). favoring the development of certain bacteria (anaero- – Anaerobes: Gram-positive bacilli Lactobacillus( spe- bes and enterobacteria) to the detriment of species of cies, 10%-43%, Eubacterium species, 0%-7%, Bifido- lactobacilli. This is why this period is usually crucial for bacterium species, 8-10%, Propionibacterium species triggering and progress of an infection of the upper geni- 2%-5%, Clostridium 4%-17%); Gram-positive cocci tal tract. In postmenopausal women, the microbiota is (Peptococcus and Peptostreptococcus); Gram-negati- very variable owing to the reduction in hormone (estro- ve cocci and bacilli (Prevotella bivia, Porphyromonas gens) and common anatomical structural changes (eg, asaccharolytica, fragilis group Bacteroides, and Fuso- prolapse, episiotomy scars). In elderly women, epithelial bacterium species). atrophy leads to recurrences and reinfections that gene- – Yeasts 15%-30%. rally involve low-virulence endogenous microorganisms The vaginal microbiota is not a static population but a (Table I and Figure 2). dynamic one, where types and levels of microbial popu- Furthermore, normal vaginal discharge is characterized lations fluctuate continuously within a changing environ- by vaginal wall transudate and cervical mucus that is clear, ment. The changes are produced by endogenous factors whitish, viscous, odorless, homogeneous and has a ph of (age, menstrual cycle, and pregnancy) and by exogenous < 4.5. It is also characterized by the presence of polymor- factors (sexual relations, antibiotics, tampons, contracep- phonuclear leukocytes (< 10 per field of x400 noncluste- tives, and vaginal hygiene habits) (7).