The majority of dermal wounds are colonized with aerobic and anaerobic microorganisms that originate predominantly from mucosal surfaces such as those of the oral cavity and gut. The role and significance of microorganisms in wound healing has been debated for many years. While some experts consider the microbial density to be critical in predicting wound healing and infection, others consider the types of microorganisms to be of greater importance. However, these and other factors such as microbial synergy, the host immune response, and the quality of tissue must be considered collectively in assessing the probability of infection. Debate also exists regarding the value of wound sampling, the types of wounds that should be sampled, and the sampling technique required to generate the most meaningful data. In the laboratory, consideration must be given to the relevance of culturing polymicrobial specimens, the value in identifying one or more microorganisms, and the microorganisms that should be assayed for antibiotic susceptibility. Although appropriate systemic antibiotics are essential for the treatment of deteriorating, clinically infected wounds, debate exists regarding the relevance and use of antibiotics (systemic or topical) and antiseptics (topical) in the treatment of nonhealing wounds that have no clinical signs of infection. In providing a detailed analysis of wound microbiology, together with current opinion and controversies regarding wound assessment and treatment, this review has attempted to capture and address microbiological aspects that are critical to the successful management of microorganisms in wounds

The obligately anaerobic bacterium Bacteroides fragilis, an opportunistic pathogen and inhabitant of the normal human colonic microbiota, exhibits considerable within-strain phase and antigenic variation of surface components. The complete genome sequence has revealed an unusual breadth (in number and in effect) of DNA inversion events that potentially control expression of many different components, including surface and secreted components, regulatory molecules, and restriction-modification proteins. Invertible promoters of two different types (12 group 1 and 11 group 2) were identified. One group has inversion crossover (fix) sites similar to the hix sites of Salmonella typhimurium. There are also four independent intergenic shufflons that potentially alter the expression and function of varied genes. The composition of the 10 different polysaccharide biosynthesis gene clusters identified (7 with associated invertible promoters) suggests a mechanism of synthesis similar to the O-antigen capsules of Escherichia coli.

Clostridium difficile-associated diarrhoea (CDAD) presents mainly as a nosocomial infection, usually after antimicrobial therapy. Many outbreaks have been attributed to C. difficile, some due to a new hyper-virulent strain that may cause more severe disease and a worse patient outcome. As a result of CDAD, large numbers of C. difficile spores may be excreted by affected patients. Spores then survive for months in the environment; they cannot be destroyed by standard alcohol-based hand disinfection, and persist despite usual environmental cleaning agents. All these factors increase the risk of C. difficile transmission. Once CDAD is diagnosed in a patient, immediate implementation of appropriate infection control measures is mandatory in order to prevent further spread within the hospital. The quality and quantity of antibiotic prescribing should be reviewed to minimise the selective pressure for CDAD. This article provides a review of the literature that can be used for evidence-based guidelines to limit the spread of C. difficile. These include early diagnosis of CDAD, surveillance of CDAD cases, education of staff, appropriate use of isolation precautions, hand hygiene, protective clothing, environmental cleaning and cleaning of medical equipment, good antibiotic stewardship, and specific measures during outbreaks. Existing local protocols and practices for the control of C. difficile should be carefully reviewed and modified if necessary.

SUMMARY.The development of the bacterial flora of neonates during the first week of life was studied in 23 babies. Specimens of meconium or faeces were collected and swabs taken from the umbilicus and mouth on days 1, 2, 3 and 6. The bacteria present were isolated on a variety of plain and selective media. The predominant faecal organisms by the end of the first week were anaerobes. Bifidobacteria were isolated from all the neonates and bacteroides and clostridia were isolated from 78.3%. Bifidobacteria and bacteroides were present in large numbers; other species were isolated in smaller numbers. Enterococci were isolated from all neonates, enterobacteria from 82.6%, anaerobic cocci from 52.2%, and streptococci and staphylococci from 34.8% each.Staphylococcus aureus was the predominant species isolated from the umbilicus; it was isolated from 21.7% of neonates on the first day rising to 87.0% by the sixth day and represented 49% of isolates from this site. S. albus, streptococci, enterococci and Escherichia coli were each isolated from a few neonates.Viridans streptococci (3 1 -4% of isolates) and Streptococcus salivarius (251%) were the commonest species recovered from the mouth. They were present from 8 h after birth; S. albus and Neisseria spp. were isolated later on the first day, and anaerobic species of Veillonella and Bijidobacterium appeared on the second day. INTRODUCTIONThe normal fetus is sterile until shortly before birth, as long as the amniotic membrane remains intact. After birth, the neonate rapidly acquires commensal bacteria that colonise the skin and mucous membranes. The host defence mechanisms are not well developed at this stage and some commensals may become opportunist pathogens, particularly in compromised neonates who must remain in hospital for the treatment of congenital abnormalities.The gastrointestinal 'tract is colonised soon after birth, mainly by facultative bacteria. Mata, Mejicanos and Jimenez (1 972), Bullen, Tearle and Willis (1 976) and Long and Swenson (1977) have shown that anaerobes colonise the neonatal gastrointestinal tract during the first week of life and are greater in number and variety than aerobes or facultative species. Subsequently, only ~ ~~

A reference library of types of Clostridium difficilehas been constructed by PCR ribotyping isolates (n = 2,030) from environmental (n = 89), hospital (n = 1,386), community practitioner (n = 395), veterinary (n = 27), and reference (n = 133) sources. The library consists of 116 distinct types identified on the basis of differences in profiles generated with PCR primers designed to amplify the 16S-23S rRNA gene intergenic spacer region. Isolates from 55% of infections in hospitals in the United Kingdom belonged to one ribotype (type 1), but this type was responsible for only 7.5% of community infections.