Pattern of maternal vaginal flora in labor and its effect on the newborn

Background: Neonatal sepsis is the most important cause of morbidity and mortality in developing countries. Early onset sepsis is attributed to abnormal bacterial colonization of the maternal urogenital tract which leads to either an ascending but silent amniotic fluid infection or symptomatic chorioamnionitis. Aims & Objectives: 1. To study the pattern of maternal vaginal flora in labor. 2. To study the outcome in the neonate. Methods: This study was conducted on 250 mothers in labor & their babies followed up till discharge in the departments of OBG & neonatology in a tertiary care medical college hospital, Deliveries by caesarean section were excluded. Results: Out of 250 mothers 130 (52%) of them showed colonization. Out of the 130 babies born to colonised mothers, 50 (38.46%) showed features of sepsis, while only 10 (8.34%) born to non-colonised mothers had features of sepsis. This study showed a statistically significant association between features of sepsis in babies and maternal vaginal colonization. Of the 60 babies with suspected sepsis, 40 had positive blood culture which is the gold standard investigation for sepsis. All of these culture positive babies i.e all 40(100%) had maternal colonization with a statistically significant association. Conclusion: This study shows that maternal vaginal colonisation has significant association with neonatal sepsis. Hence, finding the organism in the maternal vaginal flora and treating it as per sensitivity might result less cases of neonatal sepsis.


Introduction
The new-born period is one of the phases of increased vulnerability to infections and this threat begins right from the intrauterine period and passage through the maternal birth canal.
Neonatal sepsis is the single most important cause of neonatal morbidity and mortality in the community, accounting for around 30-50%. As many as 2% of fetuses are infected in utero, and up to 10% of infants have infections in the 1 st month of life [1].
The incidence of sepsis in developing countries is higher (1.8-18/1000) than the incidence in developed countries (1-5/1000 year and 98% of mortality are from developing countries. Neonatal deaths in developing countries were caused by infections (42%), asphyxia and birth trauma (29%), preterm babies and low birth weight (10%), congenital abnormalities (14%) and other causes (4%). Although the infection can be caused by viruses, fungi, and parasites, bacterial infection is the leading cause in neonatal sepsis [2].
The exposure that occurs during pregnancy or during childbirth is classified into early onset sepsis (early onset) and the exposure that occurs after birth is classified into slow-onset sepsis (late onset) [3].
Early onset sepsis is attributed to abnormal bacterial colonization of the maternal urogenital tract which leads to either an ascending but silent amniotic fluid infection or symptomatic chorioamnionitis [4].
Pediatric Review: International Journal of Pediatric Research Aailable online at: www.pediatricreview.in 741|P a g e Abnormal bacterial colonization of the rectum and anus during pregnancy may create an abnormal vaginal and cervical microbial environment. Studies in the West have revealed Group B Streptococcus (GBS) causing infection among 1-2/1000 live births with mortality rates up to 20% in affected neonates due to preterm labour, sepsis, respiratory distress and meningitis or sometimes benign asymptomatic colonization [5].
In developing countries where the incidence of neonatal sepsis is high and is the leading cause of mortality in the new-born, the role of GBS is not conclusively proved and many other organisms have been suspected to be instrumental [6].
Identification of the abnormal colonization of the genital tract by a culture based approach has been recommended by the CDC 2000. This will definitely aid in the early recognition of mothers who need to be effectively treated which in turn will prevent newborn infections.
Furthermore, a baseline knowledge of empirical antibiotic therapy in clinically suspected sepsis of early onset can be standardised and established in our situation. In the long run reduction in neonatal mortality and morbidity can be achieved [7].

Aims & Objectives
1. To study the pattern of maternal vaginal flora in labor.

Methods
Place of study: This study was conducted on all mothers in labor and their newborns followed up till discharge in the departments of OBG and Neonatology in a tertiary care medical college hospital in Tiruvalla Kerala.

Type of study:
The study was a cross sectional study conducted between September 2007 to August 2008.

Inclusion criteria
1. 250 mothers in labor& their newborn were included in the study. 2. Only mothers who underwent normal delivery were included 3. The aims and objectives of the study were explained to the mothers and the study was conducted after obtaining their consent.
Exclusion criteria-Deliveries by caesarean section were excluded. All mothers in labor were interviewed and detailed history taken regarding age, parity, socioeconomic status, antenatal problems. High vaginal swab was taken without local cleaning using Gusco's speculum from the posterior fornix as per CDC recommendations. The swab was then immediately transported to the microbiology lab and swabs were cultured using standard culture methods.The swabs were inoculated onto Blood agar, Chocolateagar, McConkey's agar and Thioglycolate medium and incubated and results evaluated at the end of 48-72 hours with the help of a qualified microbiologist. Group B Streptococcus was looked for by watching for lysis on blood agar.
The babies of these mothers were evaluated twice daily with regard to temperature, skin color, feeding, activity and those babies with suspected sepsis were identified. These babies were then subjected to Blood culture which is the gold standard for neonatal sepsis and other tests as the need demanded. These babies were given an empirical treatment with I.V antibiotics Ampicillin and Amikacin, the duration of which was determined by the culture reports. All the babies completed treatment successfully and were discharged in a healthy condition. The effect of various maternal parameters on vaginal colonization and the effect of maternal colonization on various neonatal parameters were studied.   Table 2 shows the effect of age on vaginal colonization. Of the 250 mothers 10 were below 20 years and all of them (100%) were found to have vaginal colonization with a statistically significant (p<0.05) decrease in colonization with increasing age. Non-primi 20 (25%) 60 (75%) 80 Table 3 shows the relation between parity and vaginal colonization. Out of the 250 mothers in labor, 170 were primigravida with 110 (64.7%) of them having vaginal colonization, where as among the non-primi mothers 25% showed colonization. This study showed a statistically significant (p<0.05) association between primi mothers and vaginal colonization   Table 5 shows the relation between blood culture positivity and maternal vaginal colonization. Of the 60 babies with suspected sepsis, 40 had positive blood culture which is the gold standard investigation for sepsis. All of these culture positive babies i.e. all 40(100%) had maternal colonization with a statistically significant association In this study 40 babies had blood culture positive sepsis. All of them had colonized mothers. The predominant organism grown in the blood culture was Coagulase negative Staphylococcus (CoNS) (75%) in 30 babies with 10 of their mothers having CoNS as the vaginal flora as well, with a blood culture and vaginal colonization showing a correlation in 33.33% of cases.

Discussion
The present study conducted in 250 pregnant women and their newborns conforms to previous studies in some aspects and points to some interesting observations contrary to previous studies in others.
Neonatal sepsis causes about 718.000 deaths each year or about 23.4% of the 3.1 million deaths in 2010 [8]. Neonates are particularly vulnerable to infection in the first week of life. There are 42% of deaths in the first week of life caused by infection [9]. EONS (early onset neonatal sepsis) is generally caused by microorganisms that obtained from the mother before or during the birth process. Maternal genital tract organisms have an important role in EONS incidence [10]. Rectovaginal colonization of pregnant women was suspected to be a risk factor for neonatal sepsis within the first seven days of life [11].
The present study yielded Coagulase Negative Staphylococcus (CoNS) in 20% of the cases, followed by Escherichia Coli, Klebsiella, and Candida spp. In 13.3% of the cases. Hall etal also observed Coagulase Negative Staphylococcus (CoNS) as the most common organism in their study [12]. This is comparable to other Indian studies by Vidya Ayengar et al, Ahmedabad [13], Stoll Barbara et al [14] & Habeebullah et al [15]which also did not yield GBS as the incidence of GBS colonization in India is quite low(19% ).
In a study from Delhi the most common organism isolated from maternal genital tract was Esch. coli followed by Staphylococcus aureus and Klebsiella-Spp [16].  [17] which names maternal age of <20 years as one of the predisposing factors for vaginal colonization. The possible explanations could be either decreased local resistance due to thin vaginal epithelium or a relatively higher pH; predisposing to colonization. From Table 3, vaginal colonization seems to be more in primipara (64.7%) which conforms to the study by Meharban Singh et al [17] where in primipara are said to be at an increased risk of colonization. Table 4 showed that 60 of the babies had suspected sepsis and 50 (38.46%) of these were born to colonized mothers, while only 8.34% of them were born to non-colonized mothers. This conforms to the study by Vikas Gautam et al [18].
The present study showed that 50 of the 60 babies with suspected sepsis were born to colonized mothers and 40 (80%) of these had confirmed sepsis i.e. blood culture positivity. It was found that of the 40 babies with blood culture positivity, all were born to mothers with vaginal colonization; and not a single one was born to non-colonized mothers. This was considered as a significant observation, given the 82% sensitivity and 96% specificity of blood culture in the detection of neonatal sepsis in accordance with the Edward Squire et al study [4].
In the present study, Co NS was grown in blood culture in 75% of cases, followed by Enterococcus in 10% of the cases, which was similar to E.S Shinewell et al [19]. Other similar studies have shown different  [20] and Klebsiella, E. coli, Acinetobacter [21].
Rectovaginal bacterial colonization of pregnant women and chorioamnionitis has a positive correlation with the incidence of early-onset neonatal sepsis. Babies who born from mothers with chorioamnionitis lead to bacterial colonization and sepsis faster [22].
There are a number of parallels between maternal genital colonization with group B streptococcus and with E. coli. Both bacteria probably colonize the vagina from a rectal source and do not usually cause an infection of the vaginal epithelium. These two bacteria are of interest and concern because of their vertical transmission to the neonate and their role in neonatal sepsis, meningitis, and death [23].

Summary
 38% of babies born to colonized mothers had suspected sepsis, compared to 8% in those born to non-colonised mothers.
 Blood culture positivity was found only in those babies born to colonized mothers.
 CoNS was the predominant pathogen in 75% of cases, followed by Enterococcus in 10%.
 10 mothers of babies with CoNS had the same organism as their colonizer, with 33% correlation in the pathogen

Conclusion
52% of mothers in labor had vaginal colonization, predominantly CoNS.80% of babies of these mothers had culture proven sepsis. The same organism was obtained in both mother and baby with sepsis in 33%.
Contrary to the western studies and our popular belief, Group B Streptococcus was not a significant issue in proven neonatal sepsis in the present study.