Experiences of intimate partner violence (IPV) among females with same-sex partners in South Africa: what is the role of age-disparity?

BACKGROUND: South African women have been exposed to epidemic proportions of intimate partner violence (IPV) amongst heterosexual relationships but not much is known about same-sex partnerships. Sexual minorities are excluded from research but are subject to intimate partner violence as much as heteronormative persons. The purpose of this study is to determine the association between age-disparity and IPV outcomes among females with same-sex partners in South Africa. METHODS: A cross-sectional study of the nationally representative South African National HIV Prevalence, Incidence, Behaviour and Communication Survey (SABSSM 2017) is used. A weighted sample of 63,567 female respondents identified as having a same-sex partner are analysed. IPV is measured as ever been physically and/ or sexually abused. Any experience of IPV is included in the dependent variable of this study. Descriptive and inferential statistics are used to estimate the relationship between demographic, socioeconomic, age-disparity and IPV. RESULTS: Almost 16% of females in same-sex relationships experienced IPV and about 22% from younger partners. In female same-sex partnerships, partner age-disparity (OR: 1.30, CI: 1.18 - 1.51), type of place of residence (OR: 2.27, CI: 1.79 - 3.79), highest level of education (OR: 1.07, CI: 0.97 - 1.17), marital status (OR: 1.60, CI: 1.37 - 1.88), and race (OR: 1.47, CI: 1.41 - 1.54) are associated with an increased likelihood of violence. CONCLUSION: IPV programs that are specifically targeted for non-heteronormative orientations are needed. These programs should promote health equity and safety for non-confirmative sexual identities in the country.

Perpetuation of household food insecurity during COVID-19 in South Africa.

BACKGROUND: Perpetual food insecurity has long-term health and development effects on populations. The global pandemic created sub-populations that were newly food insecure, but there exists sub-populations were food insecure, and COVID-19 held that situation. This study seeks to identify the demographic and socioeconomic characteristics of the perpetually food insecure in South Africa in order to obtain specific evidence of populations to be prioritised in the post-pandemic era. METHODS: Secondary data from the South African National Income Dynamics CRAM Survey for rounds (Waves) 1 and 5 are analysed. The study population are those respondents who reported a household member not having enough food to eat in the early stages of the pandemic (1st round) and remained without sufficient food a year later (5th round). The study controls for the demographic and socioeconomic characteristics of the population but also changes to employment status, social grant access and willingness to be vaccinated. Descriptive and analytical statistical tests are used. RESULTS: A total of 26.15% of respondents were food insecure at the start of the pandemic. Of these, 41.09% remained food insecure a year later. The drivers of perpetual food insecurity during the pandemic include unemployment (OR = 2.09; CI 1.335293-3.265678), still being unemployed (OR = 1.86; CI 1.308032-2.636252), seven or more (≥ 7) household members (OR = 1.24; CI 1.1611329-1.610126), those with only a primary education (OR = 1.11; CI 1.5051066-2.434695), participants between the ages of 45 and 64 years old (ORs = 1.03 and 1.20; CIs 1.0171956-1.0171956 and 1.1733304-2.144875, respectively) and women (OR = 1.09; CI 1.0745444-1.406035). CONCLUSIONS: South Africa needs to address socioeconomic challenges and inequalities to assist the perpetually food insecure and to ensure that, should there be a pandemic resurgence, or a new pandemic, individuals and households in the country are in a better financial situation and appropriately supported to avoid food insecurity at all costs.

School attendance among refugee children with disabilities residing in South Africa: A cross-sectional, descriptive study.

Refugee children with disabilities are entitled to an education under South African law. These children face the challenges of living in a different country and having to manage their disabilities. However, without providing a quality education to refugee children with disabilities, they face lifelong challenges including poverty and exploitation. This nationally representative cross-sectional study, examines the prevalence of school attendance of refugee children with disabilities in South Africa. Using the Community Survey of 2016, 5,205 refugee children with disabilities are identified and studied. Descriptive statistics are used and results show that less than 5% of refugee children with disabilities are in school. Further there are differences across province of residence, sex and other sociodemographic characteristics. This study is a starting point for more quantitative analysis and further qualitative analysis on the barriers to education for refugee children with disabilities in the country.

"Did You Wash Your Hands?" The Socioeconomic Inequalities Preventing Youth From Adopting Protective Behaviors During COVID-19 in South Africa.

Background. Behavior change has been a critical factor in slowing the spread of COVID-19. In South Africa where infection rates are high, research is needed on the protective behaviors adopted by youth who have low infection rates but are carriers of the virus. Aims. The purpose of this study is to (1) identify the protective behaviors young people adopted during the pandemic and (2) to estimate the probability of positive behavior change by demographic and socioeconomic characteristics. Methods. The study uses data from the South African National Income Dynamics-Coronavirus Rapid Mobile Survey 2020. The sample includes 985 (n) youth aged 15-24 years. The outcome of interest is behavior change due to the Coronavirus. Cross-tabulations and an adjusted binary logistic regression model showing odds ratios, are fit to the data. Results. Not all youth adopted protective behaviors. The most prevalent behaviors adopted include washing hands (67.75%) and staying at home (54.02%). Youth in households with six or more members are more likely to change their behaviors (ORs = 1.67 and 1.64, both p-values < .05). However, youth who do not have access to water to wash hands (OR = 0.71), reside in households with food insecurity (OR = 0.94), and those living in nonformal housing (OR = 0.69) are less likely to adopt behavior change. Conclusion. Due to the socioeconomic inequalities associated with behavior change, there is need for more tailored approaches to address youth living in impoverished households in the country.

Socio-ecological determinants of under-five mortality in Nigeria: exploring the roles of neighbourhood poverty and use of solid cooking fuel.

Globally, despite the decline in under-five mortality rate from 213 per 1000 live births in 1990 to 132 per 1000 live births in 2018, the pace of decline has been slow, and this can be attributed to poor progress in child survival interventions, including those aimed at reducing children's exposure to household pollution. This study examined the influence of neighbourhood poverty and the use of solid cooking fuels on under-five mortality in Nigeria. Data for the study comprised a weighted sample of 124,442 birth histories of childbearing women who reported using cooking fuels in the kitchens located within their house drawn from the 2018 Nigeria Demographic and Health Survey. Descriptive and analytical analyses were carried out, including frequency tables, Pearson's chi-squared test and multivariate analysis using a Cox proportional regression model. The results showed that the risk of under-five mortality was significantly associated with mothers residing in areas of high neighbourhood poverty (HR: 1.44, CI: 1.34-1.54) and the use of solid cooking fuels within the house (HR: 2.26, CI: 2.06-2.49). Government and non-governmental organizations in Nigeria should initiate strategic support and campaigns aimed at empowering and enlightening mothers on the need to reduce their use of solid cooking fuels within the house to reduce harmful emissions and their child health consequences.

The impact of maternal health insurance coverage and adequate healthcare services utilisation on the risk of under-five mortality in Nigeria: a cross-sectional study.

BACKGROUND: Despite the progress in reducing under-five mortality (U-5 M) in recent years, these deaths remain considerably high in Nigeria. This could be attributed to poor health policies including inequality of health insurance coverage and access to adequate healthcare services utilisations which has remained inimical to achieving sustainable development goals (SDGs). Therefore, this study examined the impact of maternal health insurance coverage and adequate healthcare services utilisation on the risk of U-5 M in Nigeria. METHODS: The data for the study were derived from the 2018 Nigeria Demographic and Health Survey and comprised a weighted sample of 127,545 birth histories of childbearing women. Descriptive and analytical analyses were carried out, including frequency tables and multivariate using Cox proportional regression. The results were presented as hazard ratios (HR) with 95% confidence intervals (CIs). Data were analyzed using Stata software version 15.1. RESULTS: The results showed that 14.3% of the sampled birth histories of the childbearing women were children who died before age 5. The results further showed that 97.7% of the children were of mothers who have health insurance and over one-half (56.5%) were children whose mothers had adequate healthcare services utilisation. The risk of under-five death was significantly lower among the children of mothers who were covered by health insurance (HR: 0.66, CI: 0.42-1.02) and those whose mothers utilised adequate healthcare services (HR: 0.78, CI: 0.68-0.90). A similar result was observed among children whose mothers reported that distance to the health facility was not a problem (HR: 0.81, CI: 0.72-0.86). Some mothers' characteristics including educational attainment, wealth quintile and region of residence significantly influenced the risk of U-5 M. CONCLUSIONS: The study established that maternal health insurance coverage and adequate healthcare services utilisation were found to be protective factors against the risk of U-5 M. Also, the revealed low health insurance coverage of mothers calls for more pragmatic policy and intervention programmes through health insurance to achieve SDGs targets of ending preventable deaths of children under 5 years of age and ensuring quality, as well as universal access to maternal and child healthcare services.

The prevalence and socio-demographic correlates of hypertension among women (15-49 years) in Lesotho: a descriptive analysis.

BACKGROUND: Hypertensive disorders are among the leading conditions for severe maternal morbidity across all regions and have a major impact on health care costs. This study aimed to identify the prevalence and its associated socio-demographic correlates of hypertension among women of the reproductive ages in Lesotho. METHODS: The study used the Lesotho Demographic and Health Survey (2014 LDHS) data set. A total of 3353 women of childbearing age (15-49 years) whose blood pressure was measured were used for analysis. The blood pressure readings were categorized according to the JNC7 cut-offs. The dependent variable of this study is hypertension. Both bivariate and binary logistic regressions were performed to determine socio-demographic correlates of hypertension. RESULTS: Results from this study revealed that one out of every five respondents of the study had hypertension compared to 23% who were in the prehypertension stage. The situation adds to the overall future risk of hypertension. About 30% percent who were at the hypertension stage were either living with a partner or widowed. The odds of being hypertensive were significantly 9.78 times higher among women aged 45-49 years [CI: 6.38-15.00]. Other factors associated with hypertension among women of the reproductive ages were "living with a partner" [OR 3.55:95% CI: 1.76-7.16], widowed [OR 2.61:95% CI: 1.89-3.60], and residing in the Maseru district [OR 2.12: 95% CI: 1.49-3.03]. CONCLUSION: Chances of being diagnosed with high blood pressure increased with an increase with the age of the respondents. Age was found to be the most definite positive significant socio-demographic correlate of hypertension among women in Lesotho. To control hypertension, primary prevention strategies should target the identified high-risk -older age groups, the ever-married as well as prehypertensive women.

Women's attitudes towards negotiating safe sexual practices in Nigeria: Do family structure and decision-making autonomy play a role?

BACKGROUND: The risk of contracting sexually transmitted infections (STIs), including human immunodeficiency virus (HIV) is related to women's sexual attitudes, beliefs, and power dynamics within marriages in developing countries. Despite the interventions towards improving women's sexual health and well-being, women are disproportionately affected by the risk of STIs transmission compared with their male counterparts in most sub-Saharan African countries including Nigeria. This study examined the roles of family structure and decision-making autonomy on women's attitudes towards negotiating safe sexual practices in Nigeria. METHODS: The study involved analyses of data from a nationally representative and weighted sample size of 28,219 ever-married/cohabiting women aged 15-49 years from the 2018 Nigeria Demographic and Health Survey. Descriptive and statistical analyses were carried out, including frequency tables, Pearson's chi-square test, and multivariable binary logistic regression model. RESULTS: The overall prevalence of having positive attitudes towards negotiating safe sexual practices were 76.7% and 69.6% for a wife justified in asking the husband to use a condom if he has an STI and refusing to have sex with the husband if he had sex with other women, respectively. The results further showed that polygamous unions negatively influenced urban and rural women's attitudes towards negotiating safe sexual practices, but women's decision-making autonomy on how to spend their earnings was found to be a protective factor for having positive attitudes towards negotiating safe sexual practices with partners. Surprisingly, there were significant variations in attitudes towards negotiating safe sexual practices among urban and rural women who enjoyed decision-making autonomy on their healthcare (aOR 1.70; CI 1.32-2.18 and aOR 0.52; CI 0.44-0.62, respectively). Plausibly, such women might have constrained them to compromise their sexual relationships for fear of being neglected by partners. CONCLUSION: The outcomes of this study have some policy implications for both maternal and child health. There is the need to intensify programmes aimed at improving women's sexual health and rights towards achieving sustainable development goals of preventing deaths of newborns, ending STIs and creating gender in Nigeria.

Time to hypertension development among people living with HIV in South Africa: A longitudinal analysis of the National Income Dynamics Survey (NIDS).

INTRODUCTION: There is an increased risk of hypertension among people living with HIV (PLWH). Older age has been associated with a higher risk of chronic conditions. In this study, we assess the time taken before adults living with HIV develop hypertension and explore the factors associated with hypertension diagnosis among PLWH. METHODS: Retrospective analysis on (n = 95 701) HIV positive adults from the longitudinal survey data from the National Income Dynamics Survey (NIDS) in South Africa was performed. The adults (18-75 years) were followed in order to determine the age of hypertension risk. Kaplan Meier survival estimates were used to show time to diagnosis. Multivariate cox regression model was used to determine the factors associated with hypertension diagnosis. RESULTS: 10.5% had HIV and hypertension at the start of the NID survey (wave 1:2008). Of the remaining (n = 85 569), over 75% aged 30-46 were at risk of developing hypertension. Thereafter the risk of hypertension comorbidity begins to decrease after the age of 45. In other words, the risk of hypertension began to reduce once the adults living with HIV turned 45 years old. There was no significant association between the development of hypertension comorbidity and the other demographic, socio-economic and health characteristics assessed. CONCLUSION: Young adults living with HIV are also at risk of hypertension. HIV infected persons need to routinely screen for chronic diseases and started on treatment timeously.

The comorbidity of HIV, hypertension and diabetes: a qualitative study exploring the challenges faced by healthcare providers and patients in selected urban and rural health facilities where the ICDM model is implemented in South Africa.

BACKGROUND: PLWH are living longer as a result of advancement and adherence to antiretroviral therapy. As the life expectancy of PLWH increases, they are at increased risk of hypertension and diabetes. HIV chronic co-morbidities pose a serious public health concern as they are linked to increased use and need of health services, decreased overall quality of life and increased mortality. While research shows that integrated care approaches applied within primary care settings can significantly reduce hospital admissions and mortality levels among patients with comorbidities, the primary care system in South Africa continues to be challenged with issues about the delivery of quality care. METHODS: This study applied a phenomenological qualitative research design. IDIs were conducted with 24 HCPs and adults living with the comorbidity of HIV and either hypertension or diabetes across two provinces in South Africa. The objective of the research was to understand the challenges faced by HCPs and patients in health facilities where the ICDM model is implemented. The health facilities were purposively sampled. However, the HCPs were recruited through snowballing and the patients through reviewing the facilities' clinic records for participants who met the study criteria. All participants provided informed consent. The data was collected between March and May 2020. The findings were analysed inductively using thematic content analysis. RESULTS: The challenges experienced included lack of staff capacity, unclear guidelines on the delivery of integrated care for patients with HIV chronic comorbidities, pill burden, non-disclosure, financial burden, poor knowledge of treatments, relocation of patients and access to treatment. Lack of support and integrated chronic programmes including minimal information regarding the management of HIV chronic comorbidities were other concerns. CONCLUSION: The outcomes of the ICDM model need to be strengthened and scaled up to meet the unique health needs and challenges of people living with HIV and other chronic conditions. Strengthening these outcomes includes providing capacity building and training on the delivery of chronic care treatment under the ICDM model, assisted self-management to improve patient responsibility of chronic disease management and strengthening activities for comorbidity health promotion.

The prevalence and contextual correlates of non-communicable diseases among inter-provincial migrants and non-migrants in South Africa.

BACKGROUND: The socioeconomic conditions of different environments manifest in varying experiences of illnesses. Even as migrants do transit across these different environments for various reasons, including settlement, they are bound to have peculiar experiences of diseases, which could be traced to lifestyle, gender, adaptation, and reactions to specific social, economic, psychological and climatic conditions. Paying attention to such unique scenarios, our study examines the prevalence and contextual correlates of non-communicable diseases among inter-provincial migrants and non-migrants in South Africa. METHODS: Data was from the National Income Dynamics Study (NIDS), waves 5 of 2017, which comprised of 28,055 respondents aged 15-64 years made up of 22,849 inter-provincial non-migrants and 5206 inter-provincial migrants. A composite dependent/outcome variable of non-communicable diseases (NCDs) was generated for the study and data analysis involved descriptive statistics, chi Square analysis and multilevel logistic regression analysis. RESULTS: More migrants (19.81%) than non-migrants (16.69%) reported prevalence of NCDs. With the exception of household size for migrants and smoking for non-migrants, the prevalence of NCDs showed significant differences in all the community, behavioral, and individual variables. The factors in the full model, which significantly increased odds of NCDs among the migrants and the non-migrants, were older populations, the non-Blacks, and those with higher education levels. On the one hand, being married, having a household with 4-6 persons, and being residents of urban areas significantly increased odds of NCDs among the migrant population. While on the other, living in coastal provinces, being a female, and belonging to the category of those who earn more than 10,000 Rands were significantly associated with increased odds of NCDs among the non-migrants. CONCLUSIONS: These findings, therefore, among other things underscore the need for increased education and awareness campaigns, especially among the older populations on the preventive and mitigative strategies for NCDs. In addition, changes in lifestyles with regard to smoking and physical exercises should be more emphasized in specific contextual situations for the migrant and non-migrant populations, as highlighted by the results of this study.

Healthcare beliefs and practices of kin caregivers in South Africa: implications for child survival.

BACKGROUND: Appropriate health-seeking practices may have a positive influence on child survival, particularly when practiced by kin caregivers of children who are below the age of 5 years. While literature has shown that children who are raised in kinship care often present with poor health outcomes and often have unmet healthcare needs, the health-seeking behaviours and practices of the children's kin caregivers that ultimately influence these health outcomes remain largely unknown. In this paper, we explored the healthcare beliefs and practices of kin caregivers in South Africa on child survival. METHODS: Overall, 12 structured interviews were conducted with all the participants. Six [6] interviews were conducted in the Eastern Cape province and 6 were conducted in the KwaZulu-Natal province. The sample of participants was obtained by seeking permission from the child welfare authorities in the KwaZulu-Natal and Eastern Cape Department of Social Development (DSD) to assist in identifying a sample of the kin-caregivers who have provided primary care to children below the age of 5. The structured interviews were transcribed and analysed using thematic content analysis. After thematic content analysis was carried out, transcripts were given case numbers and then imported into NViVo version 11 for analysis and interpretation of the findings. RESULTS: The healthcare seeking behaviours and poor use of healthcare services of the caregivers were largely influenced by their notions and perceptions of health and illness. The notions and perceptions that the caregivers hold about the health statuses of the children placed under their care and illness were found to be largely culturally determined and largely influenced by preconceptions and certain healthcare beliefs. Increased reliance on traditional herbs, Notion of witchcraft and Faith healing emerged as key factors that influence health-seeking practices and beliefs of kin caregivers, thus influencing under-five mortality. CONCLUSION: Kin caregivers should be equipped with the necessary guidance, resources and training that facilitate the successful fulfilment of the caregiving role, given the number of unmet needs and challenges that they face. This will in turn translate into positive child health outcomes.

Exposure to Intimate Partner Violence and Hypertension Outcomes among Young Women in South Africa.

Hypertension and intimate partner violence is affecting longevity and quality of life among women worldwide. In this study, intimate partner violence is identified as a risk factor for hypertension outcomes among young women in South Africa. Using a nationally representative sample of 216 (N) young women (15-34 years old) from the South African Demographic and Health Survey, this study uses cross-tabulations and logistic regression methods to identify the odds of hypertension outcomes. Results show that between 20 and 41% of 15-34-year-old women have hypertension. Further, 68% of women with hypertension experienced physical intimate partner violence. Finally, the odds of hypertension are increased if young women experience physical (OR: 4.07; CI: 1.04726-15.82438) or sexual (OR: 2.56; CI: 1.18198-5.55834) intimate partner violence. Efforts to reduce hypertension outcomes in the country should include intimate partner violence awareness and assistance.

The relationship between women's experience of intimate partner violence and other socio-demographic factors, and under-5 children's health in South Africa.

Women in South Africa experience high levels of Intimate Partner Violence (IPV). There are numerous health consequences experienced by victims. However, children of IPV victims often experience negative emotional and developmental outcomes as well. In South Africa, infant and child health outcomes are not optimal and IPV is high, and thus there is a need to determine whether a relationship between them exists. This study used the 2016 South African Demographic and Health Survey. Mothers aged 15 to 49 and who were included in the Domestic Violence module formed the study population. Frequency tables and graphs were done, and unadjusted and adjusted logistic regressions were performed with each of the three reported child health outcomes (birth weight, duration of breastfeeding and diarrhoea incidence), IPV and other socio-demographic factors. Thirteen percent of women have experienced IPV. Five percent of their children were low birth weight, 10% had experienced diarrhoea; but 87% had been breastfed for 6+ months. Mothers in the rich wealth category were 37% more likely to have a child born at low birth weight but those aged 20 to 39 had around a 60% less likelihood of breastfeeding for 6+ months than 15 to 19-year olds. Women who had experienced IPV had around 77% higher odds of having a child experience diarrhoea in the last 2 weeks. Wealthier mothers often have unhealthier lifestyle practices and behaviours, due to more disposable income which could account for lower birth weight children. Mothers in tertiary education and starting their professional careers are normally around 20 to 39 years and should be provided supportive structures to be allowed to breastfeed their children. The long-term emotional and developmental consequences to children of IPV victims are known, but we now know that there are also very immediate consequences to the health of these children as well.

Mucins trigger dispersal of Pseudomonas aeruginosa biofilms.

Mucus is a biological gel that lines all wet epithelia in the body, including the mouth, lungs, and digestive tract, and has evolved to protect the body from pathogenic infection. However, microbial pathogenesis is often studied in mucus-free environments that lack the geometric constraints and microbial interactions in physiological three-dimensional mucus gels. We developed fluid-flow and static test systems based on purified mucin polymers, the major gel-forming constituents of the mucus barrier, to understand how the mucus barrier influences bacterial virulence, particularly the integrity of Pseudomonas aeruginosa biofilms, which can become resistant to immune clearance and antimicrobial agents. We found that mucins separate the cells in P. aeruginosa biofilms and disperse them into suspension. Other viscous polymer solutions did not match the biofilm disruption caused by mucins, suggesting that mucin-specific properties mediate the phenomenon. Cellular dispersion depended on functional flagella, indicating a role for swimming motility. Taken together, our observations support a model in which host mucins are key players in the regulation of microbial virulence. These mucins should be considered in studies of mucosal pathogenesis and during the development of novel strategies to treat biofilms.

Swimming bacteria promote dispersal of non-motile staphylococcal species.

Swimming motility is considered a beneficial trait among bacterial species as it enables movement across fluid environments and augments invasion of tissues within the host. However, non-swimming bacteria also flourish in fluid habitats, but how they effectively spread and colonize distant ecological niches remains unclear. We show that non-motile staphylococci can gain motility by hitchhiking on swimming bacteria, leading to extended and directed motion with increased velocity. This phoretic interaction was observed between Staphylococcus aureus and Pseudomonas aeruginosa, Staphylococcus epidermidis and P. aeruginosa, as well as S. aureus and Escherichia coli, suggesting hitchhiking as a general translocation mechanism for non-motile staphylococcal species. By leveraging the motility of swimming bacteria, it was observed that staphylococci can colonize new niches that are less available in the absence of swimming carriers. This work highlights the importance of considering interactions between species within polymicrobial communities, in which bacteria can utilize each other as resources.

Material properties of biofilms-a review of methods for understanding permeability and mechanics.

Microorganisms can form biofilms, which are multicellular communities surrounded by a hydrated extracellular matrix of polymers. Central properties of the biofilm are governed by this extracellular matrix, which provides mechanical stability to the 3D biofilm structure, regulates the ability of the biofilm to adhere to surfaces, and determines the ability of the biofilm to adsorb gases, solutes, and foreign cells. Despite their critical relevance for understanding and eliminating of biofilms, the materials properties of the extracellular matrix are understudied. Here, we offer the reader a guide to current technologies that can be utilized to specifically assess the permeability and mechanical properties of the biofilm matrix and its interacting components. In particular, we highlight technological advances in instrumentation and interactions between multiple disciplines that have broadened the spectrum of methods available to conduct these studies. We review pioneering work that furthers our understanding of the material properties of biofilms.

Single particle tracking reveals spatial and dynamic organization of the E. coli biofilm matrix.

Biofilms are communities of surface-adherent bacteria surrounded by secreted polymers known as the extracellular polymeric substance (EPS). Biofilms are harmful in many industries, and thus it is of great interest to understand their mechanical properties and structure to determine ways to destabilize them. By performing single particle tracking with beads of varying surface functionalization it was found that charge interactions play a key role in mediating mobility within biofilms. With a combination of single particle tracking and microrheological concepts, it was found that Escherichia coli biofilms display height dependent charge density that evolves over time. Statistical analyses of bead trajectories and confocal microscopy showed inter-connecting micron scale channels that penetrate throughout the biofilm, which may be important for nutrient transfer through the system. This methodology provides significant insight into a particular biofilm system and can be applied to many others to provide comparisons of biofilm structure. The elucidation of structure provides evidence for the permeability of biofilms to microscale objects, and the ability of a biofilm to mature and change properties over time.

Minimal Bactericidal Concentration for Biofilms (MBC-B).

A biofilm is a multicellular consortium of surface associated microbes surrounded by a hydrated, extracellular polymer matrix. The biofilm matrix plays a critical role in preventing desiccation, acquiring nutrients, and provides community protection from environmental assaults. Importantly, biofilms are significantly more resistant to antimicrobials relative to their free-swimming counterparts. The level of antimicrobial tolerance is influenced by a number of factors, including genetic/adaptive resistance mechanisms, stage of biofilm development, and pharmacokinetics of the antibiotic. Here, we describe an in vitro microtiter-based assay to quantify the minimal bactericidal concentration for biofilms (MBC-B) for short exposure times (2 h). This exposure period is significantly shorter than standard over-night and 24-hour treatments described in traditional protocols. This assay was developed to approximate the time an antibiotic is available during a one-time treatment before it is metabolized, sequestered by host proteins, or digested.

Microfluidic-based Time-kill Kinetic Assay.

In many environments, bacteria favor a sessile, surface-attached community lifestyle. These communities, termed biofilms, are ubiquitous among many species of bacteria. In some cases, biofilms form under flow conditions. Flow chambers, and in particular microfluidic channels, can be used to observe biofilm development and physiological effects while varying nutrient conditions, flow velocities, or introducing antimicrobials to the biofilm in real time. Here, we describe a microfluidic-based kill-kinetics assay for the observation of antimicrobial effects on biofilms under flowing conditions.