| Backgroud & aims Non-lactation breast is usually in airtight state, and have little contact with the external environment. Together with the immune defense mechanism of the breast itself, pathogenic micro-organisms rarely invade into the breast. However, reports of non-lactation mastitis can be often seen. Is these inflammatory diseases endogenous-infection of breast or exogenous infection? How is the microbial status in human lactation system? What is the role of bacteria in the process of chronic mammary inflammatory disease? There is no clear answer so far.Normal human flora is the assemblage of microorganisms that reside on the surface and deep in the skin, in mucous membranes and in the natural cavity in the body. They include Bacteria, Fungi, Spirochetes, Mycoplasma, etc. Usually, they do no harm to the human body. The types and quantities of normal flora are variety. There is a close relationship between normal flora and human health and disease. Currently, the normal flora in human digestive tract, respiratory tract, the birth canal and other cavity have been largely reported, while the existence of breast intraductal normal flora is poorly studied. The study is designed to indentify the normal flora in human breast ductal system, aiming to provide some information of ecology of human lactation system and provide new ideas for the develop and prevention of mammary inflammatory disease.MethodsWe select 130 female outpatients between August 2010 and December 2010. Their age ranged from 21 to 71 years (average age: 41years). All cases underwent bilateral breast duct endoscopy, a total of 260 breasts. 100 cases lived in rural area and the other 160 lived in city. 50 cases didn,t have given any breast-feeding and the other 210 had given once or more already (including being breast-feeding). 28 cases were in lactation, and the other 232 were in non-lactation. All cases were confirmed by physical examination, B-ultrasound and breast duct endoscopy to have no obvious breast lesions. The three groups were classified according to physical examination, B-ultrasound and breast duct endoscopy. The 69 cases were asymptomatic and all the exams were normal(7 cases didn,t given any breast-feeding); the 107 were duct ectasia(12 cases didn,t given any breast-feeding); the 84 cases were galactostasis (28 at lactating period(postnatal 3 days~2 months), 56 at non-lactating period).Exclusion criteria:Acute mastitis or had signs of systemic infection; used antibiotics within 1 month; used hormones for 1 month or more recently; diabetic or any other wasting disease; bloody nipple discharge; galactorrhea; with breast tumor; menstruating.Sampling: Thoroughly washed the nipple, sterilized twice of the skin of the nipple and areola area and around it. Sterilized the nipple and areola area again after draped. After expanding the duct, filled the duct with small amount of 0.9% Natrii Chloride. Gently pressed the breast, and collected the ductal lavage with 5ml syringe through epidural catheter. Then immediately inoculated the specimens in aerobic,anaerobic and fungal media. Positive ones were identified further and colony forming units (CFUs) were counted.Judgement of bacteria contamination: It should be considered contaminated by bacteria when processing specimens if a large number of bacteria were seen to growth in non-inoculated area.Results1. 31 specimens of the 260 (11.92%) were contaminated by bacteria. Bacteria growth was observed in 62.45% of the remain 229 breasts cultured. The isolation frequency of bacteria from the galactostasis group(68.57%)had a greater percentage than the normal group(50.84% P<0.05);the isolation frequency of bacteria from the duct ectasia group(65.00%)and the normal group had no statistical difference (P>0.05).2. The top three overall detection rate of bacteria is Coagulase-negative staphylococci(28.82%), Staphylococcus aureus(20.52%), Bacillus(4.37%). There were 6 kinds of same bacteria in the normal group, the duct ectasia group and the galactostasis group, they were Coagulase-negative staphylococci, Staphylococcus aureus, group A Streptococcus pyogenes, Bacillus, Propionibacterium acnes, Peptococcus. Staphylococcus aureus and Corynebcterium in the galactostasis group had a significantly higher detection rate than the normal group(P<0.05), the detection rate of each bacteria in duct ectasia group had no significant difference compared with the normal group(P>0.05).3. 20 species of bacteria were detected from the 229 breasts, which included 7 species of aerobe, 8 species of anaerobe, 4 species of facultative anaerobe and 1 specie of fungus. There were 10, 15 and 14 bacteria identified from the normal group, the duct ectasia group and the galactostasis group, respectively. The number of indentified bacteria per person from the normal group and the duct ectasia group ranged from 0 to 3, mostly 1, there was no significant difference between the two groups on the types of bacteria(P>0.05). The bacteria from galactostasis group was mainly symbiotic, and it ranged from 0 to 3, mostly 2, and there was significant difference between the galactostasis group and the normal group on the types of bacteria(P<0.05).4. The quantitation of ductal bacteria: The quantitation of ductal bacteria from the normal group ranged from 10~110CFU/ml (average 60.67 CFU/ml), the duct ectasia group ranged from 20~180CFU/ml (average 70.00 CFU/ml), the galactostasis group ranged from 20~220CFU/ml(average 80.00 CFU/ml), The quantitation of ductal bacteria from the galactostasis group had a greater percentage than the normal group(P<0.05). but the duct ectasia group and the normal group had no statistical difference(P>0.05).5. The detection rate of bacteria on different sides of breast had no significant difference(P>0.05); those who had lactation had a higher detection rate of bacteria than those didn,t; those who had short-term weaning had a lower detection rate of bacteria than those haven weaned a long time, and the rural had a higher detection rate than the city (p<0.05).Conclusions1. The interior of human breast duct was a non-sterile environment, which can have a variety of bacterial growth. The more frequent bacteria were Coagulase-negative staphylococci, Staphylococcus aureus and Peptococcus, and the former two were the main. The quantitation of ductal bacteria ranged from 10~1~10~3CFU/ml.2. Most of the breast ducts grew one bacteria, but several bacteria can coexist. Sometimes it was a mixture growth of aerobic,anaerobic bacteria and facultative anaerobes.3. Though there was a higher detection rate and quantitation of bacteria in mammary ductal ectasia group than the normal group, there were not significant statistical difference between the ductal ectasia group and the normal group in the type and quantitation of ductal bacteria, so we can say it is non-infectious inflammatory disease.4. the type and quantitation of ductal bacteria in the galactostasis group was varies and high, particularly, Staphylococcus aureus and Corynebacterium. Therefore, measures of intervention, such as lavage the duct to these patients could reduce the opportunities of bacterial invasion, and reduce the incidence of mastitis. |
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