Health Care Associated Infections (HCAIs) are a concern especially in regards to antibiotic resistance and effective treatments. Staphylococcus aureus is often the main focus for eradication and prevention procedures, however, other bacterial species are also problematic. These include Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus epidermidis amongst others. Chronic infections caused by these bacteria are often biofilm related, and include dental caries, otitis media, osteomyelitis, burns & chronic wounds, and device related & prosthetic joint infections. Prosthetic joints and indwelling devices, such as catheters, are a prime environment on which biofilms can develop. This thesis aims to look at biofilms, investigating how they are established, the development of resistance against individual antibiotics and the antibiotic concentrations required to reduce biofilm load. A novel biofilm system – the alginate bead method will be used for these experiments, The alginate bead method was developed by a previous student in the Gallagher Laboratory, due to a need to have a reliable, robust and inexpensive technique to examine formation of biofilms and antibiotic resistance. There are devices and assays available, such as the Calgary Biofilm Device, which are extensively used for these purposes. However, the cost is prohibitive. This thesis found that the development of biofilms occurs much earlier than expected, with stable, fixed formation after just four hours of growth. Depending upon the antibiotic, resistance can develop within the first two hours of growth and thereafter steadily increases. By 24 hours the biofilms are fully resistant to all the tested antibiotics. In mixed species biofilms, the two species act synergistically protecting each other against the antibiotics, resulting in a much higher antibiotic concentration required. Common antibiotics used to treat staphylococcal infections are often combined to enhance their destructive effect and prevent the development of resistance. The effects of these antibiotics, when combined was explored. Biofilm resistance against gentamicin, one of the most common antibiotics used to treat staphylococcal infections develops quickly. However, when combined with other antibiotics gentamicin resistance is delayed. As antibiotic concentrations have to be extremely high in order to have any effect on established biofilms, alternative methods need to be investigated. Any alternative approaches would be employed in conjunction with conventional therapies preventing stable biofilm formation and disrupting established biofilms. Such methods may include sugar metabolites, enzymatic disruption, D-amino acids and activation of the quorum sensing system. The main conclusion which can be taken from this work are that firstly the alginate bead method of a viable, suitable alternative to the Calgary Biofilm Device and supports biofilm formation and testing. Secondly that biofilms form and are resistant to antibiotics much earlier than expected, and extreme concentrations of antibiotics are required to have an effect. Thus the inclusion of alternative methods which disrupt biofilms would be beneficial to clinical practice. However, the alternative methods investigated within this thesis (D-amino acids and sugar metabolites) failed to show any inhibition of biofilms. There are other possible choices which would need to be investigated.

Background: The use of antimicrobials has been presented as a significant risk factor for Clostridium difficile infection (CDI). Nevertheless, it remains unclear which antimicrobials are more likely to be associated with CDI. It is mandatory for acute trusts to report the numbers of diagnosed CDI cases to the Health Protection Agency (HPA). There is no national system to collect and analyse antimicrobial usage data from the trusts. The company IMS collects antimicrobial usage data from the trusts for creating marketing research statistics. Therefore, it was hypothesised that data collected from the HPA and from IMS could be used to undertake an ecological study about the association between CDI cases and antimicrobial use in English trusts. Methods: A trust-level Antimicrobial Usage Database provided by IMS and a database, including the numbers of CDI cases for patients aged 65 years old and above, provided by the HPA, were utilised in this work. These referred to 26 out of the 29 NW SHA trusts (that managed 64 hospitals) for the quarters between 2005 and 2008 inclusive. A sample of antimicrobial usage data collected directly from trusts was used to investigate potential limitations in using the Antimicrobial Usage Database for the purpose of this work. Multilevel models were used to study antimicrobial usage and the number of CDI cases over time. These models were also used to investigate the association between the CDI cases and antimicrobial usage in the trusts. The trends of trust antimicrobial usage over time were compared with DH recommendations for the prevention of CDI through antimicrobial prescribing published in 1994, 2005 and 2008. Results: Discrepancies between the antimicrobial usage recorded in the IMS database and in a sample of antimicrobial usage data collected from trusts were found for 31 out of 155 antimicrobial usage records; only 1 of these referred to an antimicrobial with high usage. Eight out of the 23 antimicrobial groups and 10 out of 63 antimicrobials were presented as having high usage. The antimicrobial usage over time increased significantly for 7 antimicrobial groups, decreased significantly for 2 groups and remained constant for 54 groups. The number of CDI cases reported for patients aged 65 years old and above decreased significantly over the time. Trust antimicrobial usage over time changed in the opposite direction compared to the DH recommendations published in 1994, 2004 and 2008, respectively, for 2 out of 11, 3 out of 12 and 3 out of 14 antimicrobial groups/antimicrobials. The increased usage of 5 antimicrobial groups was significantly associated with an increase in the number of CDI cases and an increased usage of 4 antimicrobial groups was significantly associated with a decreased number of CDI cases. Within the antimicrobial groups that were significantly associated with an increased number of CDI cases, the usage of 8 individual antimicrobials was significantly associated with the CDI cases. Discussion/Conclusion: Collecting antimicrobial usage over time for large groups of trusts is very time consuming and requires extensive data manipulation. The similarity of the results of this study with those of previously published studies suggest that HPA and IMS data may be used to investigate the association between CDI cases and antimicrobial usage in English trusts.

Thesis(M. Med. (Public Health Medicine)) -- University of Limpopo, 2019 / Background: Health care workers (HCWs) hands are the most common vehicle for the transmission of health care associated infections (HCAIs) between patients and the health care environment. Hand hygiene is regarded as the most important, simplest, and least expensive means of reducing the burden of HCAIs. However, hand hygiene compliance remains low among HCWs. Aim: To assess the level of knowledge, attitude and self-reported practices (KAP) of HCWs on hand hygiene and associated factors. Method: A quantitative, descriptive study using a pre-tested self-administered questionnaire was conducted among HCWs of Pietersburg Hospital. Data collection was carried out between January and February 2018. KAP scores were summarised into means, standard deviations and percentages. Chi-square and Fisher’s exact tests were used to determine association between KAP scores and selected independent variables (gender, age, profession, experience, discipline and training). Results: There were 324 respondents, mostly females (74.3%), <40 years (70.6%) and predominantly nurses (52.4%). Majority had moderate knowledge (79.3%), positive attitude (88.8%) and good practices (87.9%). Respondents had knowledge gaps on HCAIs, WHO “Five (5) moments for hand hygiene” and alcohol based hand rub. Association was found between respondent’s KAP scores and age (p<0.05). Nursing profession was associated with good practices (p=0.000). Knowledge and attitude were associated with years of clinical experience (p<0.05). Positive attitude (p=0.019) and good practices (p=0.000) were associated with training in the last 3 years. No significant relationship was found between KAP and undergraduate training. Conclusion: Most respondents had moderate knowledge, positive attitude and good practices. Respondent’s variety in KAP scores and associated factors indicate that a multimodal, multifaceted improvement approach should be undertaken to address KAP gaps.