Zhang et al. BMC Women's Health (2020) 20:138 https://doi.org/10.1186/s12905-020-00997-5 RESEARCH ARTICLE Open Access Characteristics of aerobic vaginitis among women in Xi’an district: a hospital-based study Taohong Zhang1†, Yan Xue1†, Ting Yue2, Lili Xiong1, Xiaowei Wang1, Weihong Wang1, Ying Liu1 and Ruifang An1* Abstract Background: Aerobic vaginitis (AV) is a reproductive tract infection that affects health of women. The objective of this study was to analyze the characteristics of simple and mixed AV patients in Xi’an district and provide reference data for the clinical treatment of AV. Methods: Patients were recruited from the outpatient Department of Obstetrics and Gynecology in the First Affiliated Hospital of Xi’an Jiaotong University from September 2014 to April 2019 in strict accordance with inclusion and exclusion criteria. The study principally examined the vaginal ecosystem, age distribution, levels of functional enzymes, and changes in pH levels in these women. Differences within groups were analyzed. Results: A total of 284 AV patients were enrolled to investigate the distribution of simple and mixed AV infection. AV infection was found to be mainly simple infection. Simple AV patients were generally aged 50–60 years, while mixed AV patients were mostly aged 30–40 years. In the present study, the density of vaginal bacteria (OR = 13.294, 95% CI = 5.869–30.115, P < 0.01), the type of predominant bacteria (OR = 3.962, 95% CI = 1.785–7.984, P < 0.01) and positive expression of coagulase (OR = 3.789, 95% CI = 1.798–7.984, P < 0.01) were considered risk factors for mixed AV infection. Conclusions: The epidemiology of simple and mixed AV infection were found to be different, with density of vaginal bacteria (I or IV), species that are predominant and levels of coagulase being risk factors for mixed AV infection. Keywords: Aerobic vaginitis, Vaginal flora, Mixed infection Background bacterial vaginitis (BV), cytolytic vaginosis (CV) or aer- Human vaginal flora is a complex and protective envir- obic vaginitis (AV), the clinical symptoms of which, such onment, which enables the maintenance of vaginal pH as abnormal leucorrhea, increased discharge, vulval itch- levels and microbial balance to withstand the invasion of ing, burning pain, and so on, occurring [1, 2]. Women pathogenic fungi and protozoa. However, any imbalance suffering from these conditions can experience preterm in the naturally occurring bacterial flora may result in premature rupture of membranes, preterm labor, amni- infections such as vulvovaginal candidiasis (VVC), otic fluid infection, chorioamnionitis, sexually transmit- ted infections, and cervical intraepithelial neoplasia * Correspondence: [email protected] disease [3–6]. Taohong Zhang and Yan Xue Joint First Author AV was first identified by Donders and co-workers in 1Department of Obstetrics and Gynecology, the First Affiliated Hospital of Xi’an Jiaotong University, No.277, Yanta Western Road, Xi’an 710061, Shaanxi 2002 [7, 8]. In contrast to BV, the prevalence of AV is Province, China 7–12%, less prevalent than BV [4]. AV can cause various Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. 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BMC Women's Health (2020) 20:138 Page 2 of 7 vaginal symptoms, including stinging and dyspareunia, genital malignancy; (2) women without test results for purulent discharge with significant inflammation and enzyme activity or microscopic test of vaginal secretion; epithelial disruption, a thick cottage-cheese-like dis- (3) women who were pregnant, menstruating or lactat- charge associated with vaginal and vulvar pruritus, pain, ing; (4) women who had undergone chemotherapy, burning, erythema, and edema. Secondary infections radiotherapy or hormonotherapy due to a malignancy. may also occur, the outcomes of which can be serious, Before recruitment to the study, informed consent was including miscarriage, chorioamnionitis, premature rup- obtained from each patient. And the study protocol was ture of membranes, preterm delivery, infertility, and pel- approved by the ethics committee of the First Affiliated vic inflammatory disease (PID) [9]. However, the Hospital of Xi’an Jiaotong University. pathogenesis of AV remains unclear although it is under investigation. A preview study indicated that it resulted Sampling and tests from an immunological response with increased inflam- The bladder lithotomy position was used for matory reaction [10]. In addition, the microflora in AV gynecological examination and collection of vaginal dis- comprises commensal aerobic microorganisms of intes- charge from patients who had symptoms such as in- tinal origin, principally Escherichia coli, Staphylococcus creased discharge, vulval itching, burning pain, etc. Two aureus and coagulase-negative Staphylococci [7, 11]. A vaginal smears were obtained from the upper 1/3 of the recent study indicated that being unmarried, use of an lateral vaginal wall for microbiological analysis using intrauterine device, long-term use of antibiotics, and fre- standard microbiological methods, analysis of pH value quent vaginal douching were risk factors for AV [12]. of the vaginal environment, amino acid odor testing, and The principal diagnostic technique for identification of evaluation of enzymes using a diagnostic strip set for AV is currently observation of a wet film of vaginal se- vaginitis (Chaoshi-Bio, Jiangsu, China). cretion under a light microscope, combined with clinical manifestations. However, assessment of a wet film can Diagnostic criteria lead to errors due to the subjective judgment of clini- (1) AV: Common criteria employed for the diagnosis of cians. In addition, results of diagnosis vary across differ- AV in patients is Donders’ score or Tempera evaluation ent hospitals, regions and even countries depending on [13], but they lack standardization or recognized criteria. the levels of knowledge and skills of investigators. There- However, in accordance with the Chinese expert consen- fore, this study aimed to investigate the characteristics of sus on the clinical application of vaginal microecological distribution of AV in patients, the levels of vaginal en- assessment from 2016, AV was assessed and diagnosed zymes and pH values, to explore the use of particular va- using Donders’ score in the present study [14]. Diagnos- ginal enzymes in diagnosis, and provide reference data tic criteria and the corresponding AV scores are dis- for the reliable and objective diagnosis of AV in the played in Table 1. Scores of 0 to 10 were assigned to future. each sample, representing different levels of bacterial flora, epithelial disruption, and inflammation: 0–2 (no Methods AV), 3–4 (mild AV), 5–6 (moderate AV), or 7–10 (se- Subjects vere AV). (2) BV: BV was diagnosed using Nugent scor- A retrospective study was conducted in the Gynecology ing, in accordance with the Chinese expert consensus on Outpatient Clinic of the First Affiliated Hospital of Xi’an the clinical application of vaginal microecological assess- Jiaotong University from September 2014 to April 2019. ment from 2016 [14, 15]. A score of < 4 was normal, 4– Women who had symptoms, such as increased dis- 6 moderate, and > 6 was defined as BV. (3) VVC: VVC charge, itching of the vulva, burning pain, etc, were re- was diagnosed when hyphae or spores were observed in cruited to the study, in strict accordance with the 10% KOH wet microscopy. (4) Trichomonas Vagini- following inclusion and exclusion criteria. Inclusion cri- tis(TV): Active trichomonas observed using light micros- teria: (1) women with a history of sexual activity aged 18 copy. (5) CV: Cibley diagnostic criteria were used [16]. to 50 years old; (2) of Han ethnicity; (3) diagnosis of sim- ple AV infection or AV combined with VVC, BV, TV or Patient data others, according to the diagnostic criteria of vaginal in- After obtaining informed consent from each patient, pa- fections by microscopic examination and functional en- tient data were collected from AV patients, including zyme testing; (4) women not menstruating within the their age, AV infection status, density of vaginal bacteria, previous 3 days, no vaginal irrigation or drug the vagina diversity of vaginal bacteria, bacteria that were predom- within the previous 3 days, and no sexual intercourse for inant, levels of vaginal enzymes liking β-glucuronidase, 3 days prior to examination. Exclusion criteria were: (1) leukocyte esterase, coagulase, and sialidase,