Cervicovaginal aerobic microflora of women with spontaneous abortion or preterm delivery in Araraquara-Brazil

Microbiota aeróbica cérvico-vaginal de mulheres com aborto espontâneo ou prematuridade fetal em Araraquara - Brasil

CERVICOVAGINAL AEROBIC MICROFLORA OF WOMEN WITH SPONTANEOUS ABORTION OR PRETERM DELIVERY IN ARARAQUARA-BRAZIL

Maria Stella G. Raddi^* , Nancy C. Lorencetti

Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista Júlio de Mesquita Filho, UNESP, Araraquara, SP, Brasil

Submitted: June 02, 1997; Returned to authors for corrections: June 02, 1998;

Approved: July 23, 1998

SHORT COMMUNICATION

ABSTRACT

Microbiological routine exams of endocervix and vaginal specimens of 22 women with clinical history of recent spontaneous abortion or premature rupture of membranes were accomplished. Chlamydia trachomatis, Streptococcus pyogenes, Streptococcus agalactiae, Candida sp and Gardnerella vaginalis were recovered from 54.5% (12) of the women. Ureaplasma urealyticum was frequently isolated (45.5%) but 5 out of 22 had U. urealyticum only. Our report stands for the importance of quantitative as well as qualitative investigation on genital microflora in pregnant women, since it is likely to influence on pregnancy outcome.

Key words: abortion, preterm birth, genital microflora

Most abortions occur during the first trimester, which is due to chromosomal abnormalities (7). Corioaminionitis is due the most usual factor for abortion in the second trimester. Causes of prematurity can be found in few cases and the frequency of preterm births has not significantly decreases over the past 30 years, despite the widespread use of potent tocolytic agents. The major causes for such a situation has been connected with lower socioeconomic status, antepartum hemorrhage, and a background of adverse pregnancy outcome (8). In addition different researches have shown that abnormal pregnancy outcomes, i.e., preterm labor (PTL), preterm delivery (PDT), and preterm membrane ruptures, may be related to ascending genital microflora. Specific organisms such as Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Streptococcus agalactiae (group B streptococci), have all been responsible for one or more of such abnormal outcomes of pregnancy (1,5). Mycoplasma hominis and Ureaplasma urealyticum also have been suggested as causing agents for spontaneous abortion (15). The purpose of the present study was to examine the cervicovaginal microflora of women with abnormal pregnancy outcomes.

Laboratory routine of endocervix and vaginal specimens from 22 women with clinical history of recent abnormal pregnancy outcome were carried out. A specimen from the posterior fornix was collected with Ayre’s spattle, direct into saline over a slide, for evaluation of yeast and protozoa. The diagnosis was made by wet-mount microscopy. A specimen of the vaginal mucous was collectted with cotton-tipped swab, rolled over a glass slide and Gram stained, for microscopic observation and evaluation of microorganisms and polymorfonuclear leucoytes (PMN), as described by Evangelista and Beilstein (6). A cotton-tipped swab was used to transfer vaginal fluid into 5% sheep’s blood agar, 5% human’s blood agar and chocolate agar for isolation of aerobic or facultative organisms. Each agar plate was streaked into four zones, and the growth of the different species was semiquantitated, as follows: 1+,£10 colonies in the primary streak area; 2+, > 10 colonies in the primary streak area and > 10 colonies in the secondary streak area; 3+, > 10 colonies in the secondary streak area and < 10 colonies in the tertiary streak area; 4+, > 10 colonies in the tertiary streak area. Aerobic and facultative bacteria were identified by standard methods (8). A sample from endocervix was collected with dacron swab so as to isolate Chlamydia trachomatis onto cycloheximide-treated McCoy cells, and Ureaplasma urealyticum as described by Shepard (14).

Out of 22 patients 12 (54.5%) were found to have one or more organisms with recognized clinical significance, and 4 (33.4%) of these had Ureaplasma urealyticum associated. Lactobacillus sp, Corynebacterium sp, coagulase-negative staphylococci, viridans group streptococci were not tabulated. Among the 10 remaining women without any specific bacterial infection, 5 (50%) had U. urealyticum. The occurrence of the different microorganisms is shown in Table 1. These organisms were consistently present in, at least 3+, but mostly in 4+ quantities, except for U. urealyticum.

Preterm delivery has been associated with maternal genital infections, most commonly with Neisseria gonorrhoeae and group B streptococci (1). Martin et al. (9) were the first to report a relationship between cervical occurence of C. trachomatis and prematurity. The life cicle of C. trachomatis, which has been proved to replicate in human amnion cells, requires cellular death as the organism is released from the infected cell to spread to others. This cythopatic effect produces tissue injury. Symptoms as well as signs of clamydial infection are often either extremely mild or totally absent (4). Recently the presence of bacterial vaginosis in middle or late gestation has been related to PTL, PDT and preterm rupture of membranes (10).

U. urealyticum is an organism prevalent in sexually active women and its role as fetoplacental pathogenic agent is still discussed. We found it present in 40.9% of the women in this research. There is a great amount of literature dealing with compromised pregnancies and such microorganisms, including placental colonization, perinatal morbidity and mortality spontaneous abortion, amnionitis, and chorioamnionitis. All of these contribute significantly to female reprodution failure. M. hominis and U. urealyticum can colonize the endometrium with, or without evidence of inflammation. Both organisms can invade the amniotic sac in the first 16 or 20 weeks of gestation, in the presence of intact fetal membranes and in the absence of others microorganisms. The evidence of inflamatory cells and ureaplasmas in the amniotic fluid over two month period in the absence of other demonstrable microorganisms, provides a convincing argument to prove those organisms’ capacity in actually producing chorioamnionitis by themselves (11). Indirect evidence of association between U. urealyticum setorype 4 and pregnancy loss was described by Quinn et al. (12), who found higher levels of U. urealyticum antibody in women with previous unsuccessful pregnancies compared with those found in normal pregnant women.

The high concentration of potencially pathogenic microorganisms in the vagina and cervix of pregnant woman may increase the possibility of an ascending infection via the cervix, decidua, maternal placenta, and amniotic fluid. Several cervicovaginal microorganisms produce proteases, neuraminidase and mucinase, with may facilitate their passage across the cervical barriers to the lower uterine segment. Collagenases, which may focally contribute to weakness of choroamnion, is also concurrent. One theory whereby microorganisms may initiate preterm labor deals with the ability of some bacteria to produce enough protease so as to weaken the fetal membrane strength and cause rupture. Schwarez et al. (13) demonstrated that lysosomes within fetal membrane cells contain phospholipase A₂ in high concentrations. Phospholipase A₂ releases the arachidonic acid bound to fetal chorioamnion and maternal decidua tissue with the consequent rise in prostaglandin synthesis. That, in turn, stimulates uterine contractions. Benett et al. (3) demonstrated that bacterial products of group B streptococci, Escherichia coli, and Bacteroides fragilis increase the prostagladin synthesis in the membranes. Bejar et al. (2) found a high rate of phospholipase A₂ production by anaerobic streptococci, Fusobacterium sp, Bacteroides sp and Gardnerella vaginalis. It has been reported that pregnant women with vaginal colonization by facultative lactobacilli producing H₂O₂ were less likely to have bacterial vaginosis, symptomatic candidiasis, Mycoplasma hominis, or viridans streptococci.

In conclusion, the importance of investigate, quantitative as well as qualitative, genital microflora in pregnant women is fairly clear, since it appears to influence on preterm delivery or fetal loss.

ACKNOWLEDGMENT

We thank Antonio Fernando Longo Vidal for his expert medical assistance.

RESUMO

Microbiota aeróbica cérvico-vaginal de mulheres com aborto espontâneo ou prematuridade fetal em Araraquara - Brasil

Rotina bacteriológica do conteúdo vaginal e cervical de 22 mulheres com histórico de aborto recente ou ruptura precoce das membranas foi realizada. Chlamydia trachomatis, Streptococcus pyogenes, Streptococcus agalactiae, Candida sp e Gardnerella vaginalis foram isolados em 54,5% (12) das pacientes. Apesar de Ureaplasma urealyticum ter sido frequentemente encontrado (45,5%), somente em 5 das 22 mulheres foi o único microrganismo presente nos materiais analisados. Esses resultados chamam a atenção para a importância de investigação quantitativa bem como qualitativa da microbiota genital em gestantes, tendo em vista ter consequências na gestação.

Palavras-chave: aborto, prematuridade fetal, microbiota vaginal

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*

Corresponding author. Mailing address: Faculdade de Ciências Farmacêuticas, Rodovia Araraquara-Jaú, Km 1, UNESP, Caixa Postal 502, CEP 18801-902, Araraquara, SP, Brazil. Fax: [phone]

Publication Dates

• Publication in this collection
  27 May 1999
• Date of issue
  Oct 1998

History

• Received
  02 June 1997
• Reviewed
  02 June 1998
• Accepted
  23 July 1998