The role of micro-organisms (Staphylococcus aureus and Candida albicans) in the pathogenesis of breast pain and infection in lactating women: study protocol

Lisa H Amir 2 Meabh Cullinane 2 Suzanne M Garland 0 1 6 Sepehr N Tabrizi 0 1 6 Susan M Donath 5 6 Catherine M Bennett 4 Amanda R Cooklin 3 Jane RW Fisher 7 8 Matthew S Payne 1 2 0 University of Melbourne Department of Obstetrics and Gynaecology, The Royal Women's Hospital , Parkville, VIC 3052 , Australia 1 Women's Centre for Infectious Diseases, Bio 21 Institute , Parkville, VIC 3052 , Australia 2 Mother & Child Health Research, La Trobe University , Melbourne, VIC 3000 , Australia 3 Parenting Research Centre , East Melbourne, VIC 3002 , Australia 4 Deakin Population Health, Deakin University , Burwood, VIC 3125 , Australia 5 University of Melbourne Department of Paediatrics, The Royal Children's Hospital , Parkville, VIC 3052 , Australia 6 Murdoch Childrens Research Institute, The Royal Children's Hospital , Parkville, VIC 3052 , Australia 7 Centre for Women's Health, Gender and Society, University of Melbourne , Carlton, VIC 3053 , Australia 8 Jean Hailes Research Unit, Monash University , Clayton, VIC 3168 , Australia - The role of micro-organisms (Staphylococcus aureus and Candida albicans) in the pathogenesis of breast pain and infection in lactating women: study protocol Amir et al. Open Access The role of micro-organisms (Staphylococcus aureus and Candida albicans) in the pathogenesis of breast pain and infection in lactating women: study protocol Background: The CASTLE (Candida and Staphylococcus Transmission: Longitudinal Evaluation) study will investigate the micro-organisms involved in the development of mastitis and breast thrush among breastfeeding women. To date, the organism(s) associated with the development of breast thrush have not been identified. The CASTLE study will also investigate the impact of physical health problems and breastfeeding problems on maternal psychological health in the early postpartum period. Methods/Design: The CASTLE study is a longitudinal descriptive study designed to investigate the role of Staphylococcus spp (species) and Candida spp in breast pain and infection among lactating women, and to describe the transmission dynamics of S. aureus and Candida spp between mother and infant. The relationship between breastfeeding and postpartum health problems as well as maternal psychological well-being is also being investigated. A prospective cohort of four hundred nulliparous women who are at least thirty six weeks gestation pregnant are being recruited from two hospitals in Melbourne, Australia (November 2009 to June 2011). At recruitment, nasal, nipple (both breasts) and vaginal swabs are taken and participants complete a questionnaire asking about previous known staphylococcal and candidal infections. Following the birth, participants are followed-up six times: in hospital and then at home weekly until four weeks postpartum. Participants complete a questionnaire at each time points to collect information about breastfeeding problems and postpartum health problems. Nasal and nipple swabs and breast milk samples are collected from the mother. Oral and nasal swabs are collected from the baby. A telephone interview is conducted at eight weeks postpartum to collect information about postpartum health problems and breastfeeding problems, such as mastitis and nipple and breast pain. Discussion: This study is the first longitudinal study of the role of both staphylococcal and candidal colonisation in breast infections and will help to resolve the current controversy about which is the primary organism in the condition known as breast thrush. This study will also document transmission dynamics of S. aureus and Candida spp between mother and infant. In addition, CASTLE will investigate the impact of common maternal physical health symptoms and the effect of breastfeeding problems on maternal psychological well-being. Background The World Health Organization and Australian authorities recommend that babies are exclusively breastfed for the first six months of life [1,2]. During this time, and especially in the early weeks, breastfeeding women can experience a range of breastfeeding problems, in particular breast and nipple pain, or breast infections such as mastitis or breast thrush. Mastitis is an acute, debilitating infection that occurs in 15 to 20% of Australian breastfeeding women who experience a red, painful breast with fever [3,4]. Seventy five percent of mastitis episodes occur in the first seven weeks following birth [4]. It is a painful, distressing condition which may require hospitalisation or lead to development of a breast abscess [5]. Traditionally, S. aureus has been considered the most common aetiological agent of mastitis and is commonly isolated in infective mastitis and from breast abscesses [6]. However, recent studies have suggested that other micro-organisms such as coagulase negative staphylococci (CNS) may also play an important role in infectious mastitis [7,8]. CNS such as Staphylococcus epidermidis are normal inhabitants of the skin in healthy hosts and are considered commensal bacterial skin flora. The suggestion that CNS such as S. epidermidis may be involved in infective mastitis highlights that, although S. aureus is certainly one cause of mastitis, commensal skin flora which have previously been thought of as nonpathogenic, may also be responsible for this illness in a proportion of breastfeeding women [7]. Breastfeeding women may also experience burning nipple/breast pain known as breast thrush (not associated with breast redness or fever) which occurs in about 10% of breastfeeding women [9,10]. While the aetiology of mastitis has been investigated, the organism (s) associated with the development of breast thrush have not been identified. Some researchers and clinicians believe that the underlying pathogenesis in lactating women with burning nipple and breast pain is infection with C. albicans [10-12]. However, it has proved difficult to identify this organism from breast milk [13], and others attribute the pain to infection with S. aureus and treat women with long-term antistaphylococcal antibiotics [14]. Another possibility is that this syndrome could be caused by multiple organisms. Co-infection with S. aureus and C. albicans or other Candida spp in the lactating nipple and breast may be leading to inflammation and pain. These organisms co-exist in infectious conditions in other moist parts of the body, such as angular cheilitis (in the corners of the mouth) [15,16] and paronychia (infection around the finger nail) [17]. This is currently a hotly debated issue and the pathogenesis of breast thrush is unclear [18,19]. In addition to breast symptoms and infection, maternal physical symptoms in the postpartum period are common. The Victorian Survey of Recent Mothers, a state-wide postal survey of a representative cohort of 1336 women, found that at six months postpartum, 94% of the sample reported one or more health problems [20]. The most common health problems reported were fatigue (69%) (...truncated)