正常菌群对人体健康影响的研究进展

正常菌群(Nomal flora)是指在正常人体皮肤、黏膜以及人体与外界相通的各种腔道(如口腔、鼻咽腔、肠道和泌尿生殖道)等部位寄居，对人体无害的微生物丛，包括细菌、真菌、螺旋体、支原体等。正常菌群与人的健康和疾病间存在有密切的关系，它们发挥着很多重要功能，例如刺激人体免疫系统，协助机体的消化、吸收等功能。随着微生态学的发展和微生态制剂的研制，人们日益重视对正常菌群的研究。     

Response of soil bacterial community to repeated applications of carbendazim

The effect of repeated carbendazim applications on functional diversity of culturable microorganisms and bacterial community composition was studied under field conditions. The functional diversity of soil culturable microbial community (Shannon index, H') reduced significantly (P<0.05) after the first introduction of carbendazim at levels of 0.94, 1.88 and 4.70 kg active ingredient (a.i.)ha(-1) and then recovered to that in the control with subsequent applications. An evident (P<0.01) difference in the bacterial community composition was observed after the second carbendazim application by Temperature Gradient Gel Electrophoresis (TGGE) analysis of 16S rRNA genes amplified from treated and control soils, which remained after the third and fourth treatments. Our results indicated that repeated carbendazim applications have a transient harmful effect on functional diversity of soil culturable microbial community and result in an alteration in bacterial community composition largely due to one species within the γ-proteobacterium.     

The effect of antibiotic prophylaxis and topical antiseptics on the bacterial flora of the skin after cardiac surgery

A controlled trial of antibiotic prophylaxis in cardiac surgery compared a two-dose regimen of teicoplanin with a longer conventional course of flucloxacillin and tobramycin. In 12 patients the susceptibility of the bacterial skin flora of four different sites to each of the three antibiotics was determined and the results are reported here. Less than 1% of the Gram-positive colonies showed reduced sensitivity to teicoplanin (MIC greater than or equal to 4 mg l-1). Before operation, 99% inhibition of Gram-positive growth was achieved at 26 (54%) of 48 sites by 1 mg l-1 of flucloxacillin and 13 (27%) sites by 2 mg l-1 tobramycin. By the 7th day after operation there was a significant reduction in the number of sites showing similar sensitivity to flucloxacillin [16 (33%) sites, P less than 0.05]. The use of teicoplanin was not associated with the emergence of Gram-negative skin flora but tobramycin promoted acquisition of aminoglycoside-resistant strains.     

The development of bacterial flora of premature neonates

The sequential acquisition of bacterial flora by premature neonates was studied during a 10 month period. Mean gestational age of the babies was 29.01 weeks and the mean birth weight was 1.728 kg. Escherichia coli and group B streptococci (GBS) colonized the umbilicus of 7 and 6 babies respectively, out of 23 studied, on the first day of life. E. coli and staphylococci were the predominant flora on the 6th day and they colonized 12 and 13 respectively. The oral flora was predominantly Gram-positive cocci, mainly Streptococcus salivarius which was isolated from 17 out of 22 babies on the 6th day, viridans streptococci were isolated from 14 babies, Staphylococcus albus from 16 babies and group D streptococci from 11 babies. Candida spp. also colonized the oral cavities of 17 out of 22 babies on the 6th day. At the end of the first week of life, the faecal flora was predominantly anaerobic represented by Bifidobacterium spp., Bacteroides spp. and Clostridium spp. The commonest facultative faecal flora were E. coli, which was isolated from all the babies, and Strept. faecalis isolated from 20 babies. Early gut colonization by GBS, Bacteroides spp. and Clostridium spp. was noticed in more babies delivered vaginally than by caesarean section where colonization by these bacteria was relatively delayed. The use of prophylactic penicillin plus gentamicin in the special neonatal unit probably prevented systemic spread of any of the potential opportunistic pathogens during the study.     

口腔颌面部牙源性感染的菌群分布与疗效分析

目的 对口腔颌面部牙源性感染(OIOFR)的细菌进行检测分析,探讨中西医结合疗法对OIOFR的治疗效果.方法 治疗前采用需氧和厌氧培养方法分离培养183份感染标本的细菌,随机表法将口腔颌面外科收治的183例OIOFR患者分为中药治疗组、西药治疗组、中西医结合治疗组;经过3d治疗,比较3组疗效.结果 183例OIOFR患者细菌检出489株,其中厌氧菌283株占57.9％,需氧和兼性厌氧菌206株占42.1％;检出优势细菌依次为口腔链球菌群、产黑色素厌氧菌、消化链球菌和普氏菌,分别占27.6％、13.7％、10.8％、10.65％,其次是表型葡萄球菌、CO2噬纤维素菌、放线菌属、梭杆菌属、嗜血菌属、优杆菌属及奈瑟球菌属,分别占6.7％、6.3％、6.3％、6.1％、5.0、3.9％及1.8％;中药治疗组、西药治疗组、中西医结合组痊愈率分别为39.3％、57.4％和78.7％,3组疗效差异有统计学意义(P＜0.05).结论 中西医结合治疗OIOFR,标本兼治、疗程短、治疗成本低、治愈率高.     

The development of bacterial flora of premature neonates.

The sequential acquisition of bacterial flora by premature neonates was studied during a 10 month period. Mean gestational age of the babies was 29.01 weeks and the mean birth weight was 1.728 kg. Escherichia coli and group B streptococci (GBS) colonized the umbilicus of 7 and 6 babies respectively, out of 23 studied, on the first day of life. E. coli and staphylococci were the predominant flora on the 6th day and they colonized 12 and 13 respectively. The oral flora was predominantly Gram-positive cocci, mainly Streptococcus salivarius which was isolated from 17 out of 22 babies on the 6th day, viridans streptococci were isolated from 14 babies, Staphylococcus albus from 16 babies and group D streptococci from 11 babies. Candida spp. also colonized the oral cavities of 17 out of 22 babies on the 6th day. At the end of the first week of life, the faecal flora was predominantly anaerobic represented by Bifidobacterium spp., Bacteroides spp. and Clostridium spp. The commonest facultative faecal flora were E. coli, which was isolated from all the babies, and Strept. faecalis isolated from 20 babies. Early gut colonization by GBS, Bacteroides spp. and Clostridium spp. was noticed in more babies delivered vaginally than by caesarean section where colonization by these bacteria was relatively delayed. The use of prophylactic penicillin plus gentamicin in the special neonatal unit probably prevented systemic spread of any of the potential opportunistic pathogens during the study.     

The bacterial flora of neonates with congenital abnormalities of the gastro-intestinal tract

The development of the bacterial flora of neonates with congenital abnormalities of the gastro-intestinal tract was studied in 31 infants during the first 10 days of life. Specimens were collected from the umbilicus, mouth and gastro-intestinal tract on the pre-operative day, at operation and on post-operative days 1, 2, 3, 5, 7 and 10. Bacteria were isolated semi-quantitatively on a variety of plain and selective media and identified by conventional methods.     

The effect of noise on sleep--changes in hypnograms of subjects exposed to repeated truck-passing sound]

The effect of traffic noise on sleep was evaluated in an experimental room using repeated recorded truck-passing sounds. The peak sound level was 55, 60 or 65 dB (A) with frequencies of three times per hour. The background noise of the exposure night was Leq 42 dB (A) and that of the control night was Leq 35 dB (A). The subjects were five students 23 to 24 years old. The sleep stage of each epoch with a 20-second duration was judged visually based on the criteria of Rechtschaffen & Kales and the data of the second night of noise-exposure and the control night were used. The sleep parameters used were total sleep time (TST), each sleep stage, % of sleep stage against TST, sleep efficiencies, sleep latency, REM latency, REM cycle, REM duration, waking from sleep, number of stage shifts, and subjective sleep judged by the OSA sleep inventory. A paired t test was used for the statistical analysis. TST, REM stage in minutes, and % of REM stage against TST of the exposure night were significantly decreased compared with those of the control night. Other objective and subjective parameters showed no changes during noise exposure. Dividing the all-night into halves, the amount and % of each sleep stage were compared between the exposure and control night. There was no change of sleep stage in the former half, but the % and amount of REM sleep in the latter half were significantly decreased as a result of the noise exposure. The decreases of REM sleep and % REM against TST, especially in the latter half of all-night sleep, were caused by the intermittent truck-passing sounds 20 to 30 times per night.