Dominik Franciszek Dluski

The upper respiratory tract, including the nasopharynx, is inhabited by many microbial species. Still, the nasopharyngeal microbiota (or microbiome) of pregnant women is not well understood and may be influenced by a number of factors, including place of residence. Many changes occur during pregnancy, and their association with the respiratory microbiota is important for the health of the mother and for the developing fetus. The aim of this study was to compare the colonisation of the nasopharyngeal cavity by culturable aerobic bacteria in the microbiota of women with a physiological pregnancy course according to rural or urban place of residence. Nasopharyngeal swabs were collected from 37 pregnant women (17 from rural and 20 from urban areas) to detect the colonisation of aerobically growing culturable bacteria. Isolates were identified using microbiological culture methods and the MALDI-TOF MS technique. Bacteria were colonisers of the nasopharynx cavity in all cases tested. Accordingly, 97.3% (36/37) of the pregnant women were colonised by Gram-positive bacteria, mainly coagulase-negative (CoNS) and -positive (CoPS) Staphylococcus spp. and Corynebacterium spp. in both the rural and urban groups. Gram-negative Klebsiella variicola , Proteus mirabilis and Pseudomonas congelans colonised only 17.6% (3/17) of rural women and Stenotrophomonas maltophilia only 5.0% (1/20) of the urban women. To summarise, all pregnant women were colonised with bacteria in the nasopharyngeal cavity. The majority from both rural and urban residences were colonised with Gram-positive bacteria only. Gram-negative bacteria were isolated mainly from samples in the rural group.

The aim of the study was to compare the prevalence of the nasopharyngeal carriage of culturable microorganisms in the microbiota of asymptomatic women with a physiological pregnancy (PW) and nonpregnant women (NPW). Nasopharyngeal swabs were collected from 53 PW and 30 NPW to detect bacterial and fungal colonization. Isolates were identified using the culture method and the MALDI-TOF MS technique. The nasopharyngeal microbiota (NPM) partially differed between PW and NPW. These differences in the frequency of nasopharyngeal colonization between the PW and NPW groups were not statistically significant (p > 0.05); all cases were colonized by bacteria and only two cases in the PW group were colonized by yeasts, namely, Rhodotorula spp. High levels of staphylococcal colonization, including predominantly coagulase-negative staphylococci and S. aureus in the nasopharyngeal sample, were present in both groups. The reduced number of Gram-negative rods colonized in the cases studied was seen in samples from the NPW group, particularly with Enterobacterales, and anaerobic Cutibacterium spp. were isolated only in the PW group (p < 0.05). Moreover, a higher carriage rate of Enterobacter aerogenes colonization was statistically significant (p < 0.05) and correlated with the NPW group. Pregnancy may disturb the composition of the NPM represented by commensals and opportunistic bacteria and promote yeast colonization as compared to nonpregnant women.