Doctoral Degrees (Health Systems and Public Health)

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Browsing Doctoral Degrees (Health Systems and Public Health) by Subject "Communicable diseases -- Transmission"

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    Determinants of maternal colonization with multidrug-resistant gram-negative bacteria
    (Stellenbosch : Stellenbosch University, 2020-03) Bulabula, Andre Nyandwe Hamama; Mehtar, Shaheen; Dramowski, Angela; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Global Health. Health Systems and Public Health.
    ENGLISH ABSTRACT : This doctoral research explored the topic of maternal colonization with multidrug-resistant Gram-negative bacilli (MDR-GNB) in Africa, using analytical cross-sectional studies to generate novel data and systematic reviews and meta-analyses to synthesize existing data. Maternal colonization is an established risk factor for neonatal colonization, which is a precursor to neonatal infection (the third leading cause of neonatal deaths in Africa). Understanding the factors contributing to maternal colonization with MDR-GNB in Africa, will inform the development of preventive interventions and ultimately contribute to reduction of neonatal infection burden. Through a systematic review and meta-analysis, we underscored the major knowledge gaps regarding the burden of and risk factors for maternal colonization with MDR-GNB in Africa. The meta-analysis allowed us to provide a first estimate of the prevalence of maternal colonization with extended-spectrum beta-lactamases producing Enterobacteriaceae (ESBL-E) among pregnant and postpartum women in Africa (17%), which was 2 to 3-fold higher than that described from high-income countries. Utilizing an analytical cross-sectional study design, we generated unique data describing the prevalence of maternal colonization with antimicrobial resistance (AMR) genes in a South African cohort of 651 peripartum women. Cefotaxime-M15 (CTX-M15) and New Delhi Metallo-beta-lactamase (NDM) genes were isolated from 12.9% and 2.2% of specimens respectively. Communal taps as the primary water source was the only independent predictor of maternal colonization with CTX-M15. Poverty-related factors (lower educational achievement, low income group and rural residence), and a clinical factor (primiparous status), were independent predictors of maternal colonization with carbapenem-resistant pathogens. Comorbidities like HIV infection and diabetes, or exposures such as recent antibiotic use, did not predict maternal colonization with AMR genes. The knowledge, attitudes and practices regarding antibiotic use during pregnancy were assessed in a cohort of 301 pregnant South African women. Women with higher mean knowledge score (K-score) had lower reported proportions of antibiotic self-medication compared to women with lower mean K-scores. High monthly household income was an independent predictor of self-medication with The relationship between the density of hospital environmental contamination with AMR genes and colonization proportions in 180 hospitalized peripartum women and 92 neonates, was prospectively assessed. The level of hospital environmental contamination with AMR genes was low (5.8%); similarly, the number of colonized patients was small (2.8% of the peripartum women and 9.8% of the neonates), limiting the study’s power to determine a clear link between environmental contamination and patient colonization. Finally, in a second systematic review and meta-analysis, we produced a synthesis of molecular evidence linking MDR-GNB transmission from colonized mothers to their neonates. Although limited by the number and quality of studies, molecular evidence supports an overall 27% transmission proportion for MDR- and/or ESBL Enterobacteriaceae from colonized mothers to their infants, resulting in neonatal colonization. Further high-quality research is needed to determine the risk factors that promote mother-to-infant MDR-GNB transmission and evidence to link maternal MDR-GNB colonization and subsequent neonatal infection. This doctoral thesis has produced new findings on the magnitude of and risk factors for maternal colonization with MDR-GNB in an African context. The novel data will inform the development of interventions to prevent colonization with MDR-GNB in mothers and subsequently reduce neonatal infection.