DSpace Community: FACULTY OF PHARMACY

MOLECULAR CHARACTERISATION OF METALLO-BETA LACTAMASE AND OTHER RESISTANCE GENES IN PSEUDOMONAS AERUGINOSA FROM SEVEN TERTIARY HOSPITALS IN SOUTHWESTERN NIGERIA

2024-05-15T11:37:46Z

Title: MOLECULAR CHARACTERISATION OF METALLO-BETA LACTAMASE AND OTHER RESISTANCE GENES IN PSEUDOMONAS AERUGINOSA FROM SEVEN TERTIARY HOSPITALS IN SOUTHWESTERN NIGERIA Authors: OLANIRAN, O.B Abstract: The emergence of resistance to carbapenems, a last resort antibiotic, among Pseudomonas aeruginosa is of great health concern. Detailed studies on the molecular basis of carbapenem resistance in clinical P. aeruginosa isolates are scanty in Nigeria. Therefore, this study was aimed at determining the incidence of Metallo-Beta Lactamase (MBL) and other mechanisms mediating carbapenem resistance, and evaluating clonal spread among carbapenem-resistant P. aeruginosa isolates. Four hundred and forty-seven presumptive P. aeruginosa isolates collected from seven tertiary hospitals laboratories in southwestern Nigeria were identified using biochemical tests and amplification of oprI and oprL genes. Antibiogram of the isolates and Minimum Inhibitory Concentrations (MIC) were determined by Kirby-Bauer disk diffusion and broth microdilution, respectively. Phenotypic detection of carbapenemases was carried out using Modified-Hodge and combined disc tests. Carbapenem-resistant P. aeruginosa isolates were screened for class A, B and D carbapenemases, integrons and type III secretion effectors by Polymerase Chain Reaction (PCR) followed by sequencing of amplified carbapenemase genes. Transferability of MBL genes was determined by transformation experiments. Quantitative reverse transcription PCR (RT-qPCR) was used to quantify expression levels of eight efflux pump genes, ampC cephalosporinase and outer membrane porin oprD. The isolates were further genotyped using three PCR-based fingerprinting techniques. Fisher’s exact test was used to determine the association between MBL and integrons at p ≤ 0.05. Four hundred and thirty isolates were identified as P. aeruginosa of which 185(43.0%) were multidrug resistant and 50(11.6%) were extensively drug resistant. All the isolates were resistant to ampicillin, cephalothin and cefuroxime, while sensitivity to polymyxin B was most common (96.3%). The MICs ranged from 0.125 to >64 µg/mL and 0.0625 to >64 µg/mL against imipenem and meropenem, respectively. All the isolates were negative for Modified-Hodge test, while combined disc test revealed the presence of MBL. Two class B carbapenemases were detected in 86.3% of the carbapenem resistant isolates: blaVIM and blaNDM in 35.6% and 38.4% isolates, respectively, co-existing in 12.3% isolates. Fifty-one (57.5%) carbapenem-resistant P. aeruginosa strains carried class 1 integrons while class 1 and 2 integrons were present concomitantly in 12.3%. Type III effector genes, exoY and exoT were found in all isolates, while exoU and exoS were present in 49.3% and 53.4%, respectively. Two isolates possessed both exoU and exoS. Sequence analysis of blaVIM and blaNDM revealed maximum identity with blaVIM-5 and blaNDM-1, respectively. MBL genes were successfully transferred into Escherichia coli DH5α. MexXY-OprM was the most overexpressed pump (5.0 - 996.3 fold increase) occurring in 58.3% of the isolates. The ampC was overexpressed in 27.1% isolates, while oprD porin down-regulation was observed in 77.1% of the isolates. Nine disseminated clones were identified across southwestern states. There was positive association between integrons and MBL (p = 0.0064). There is a high incidence of transmissible metallo-beta lactamase genes in Pseudomonas aeruginosa from tertiary hospitals in southwestern Nigeria with different mechanisms mediating carbapenem resistance. blaVIM-5 and blaNDM-1 were found co-occurring for the first time. There is a need for surveillance of resistance to carbapenems and associated resistance genes. Description: A thesis in the Department of Pharmaceutical Microbiology submitted to the Faculty of Pharmacy in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Of the UNIVERSITY OF IBADAN

PRESCRIBING ERRORS AND INTERVENTION OUTCOMES IN SELECTED TERTIARY HOSPITALS IN NIGERIA

2019-02-07T12:43:19Z

Title: PRESCRIBING ERRORS AND INTERVENTION OUTCOMES IN SELECTED TERTIARY HOSPITALS IN NIGERIA Authors: AJEMIGBITSE, ADETUTU ADEBAMBO Abstract: Prescribing errors, particularly in the medical and paediatric specialties have been reported globally to affect up to 52.0% of hospitalized patients with potential to cause harm. Prescribing errors have however not been adequately investigated in Nigeria. This study was designed to carry out an in-depth evaluation of the nature, severity and causes of prescribing errors in three purposively selected tertiary hospitals in Nigeria with a view to providing pharmacist-led evidence-based recommendations for their prevention. A retrospective review of 8270 out-patient prescriptions and 1200 in-patient records from medical and paediatric units between January and December 2010 in National Hospital, Abuja (NHA) with University of Abuja Teaching Hospital, Gwagwalada (UATH) and University College Hospital, Ibadan (UCH) as controls. Baseline prescribing pattern was measured using the British National Formulary and Nigeria Standard Prescribing Guidelines. Causes of prescribing errors were investigated using a prospective qualitative approach involving semi-structured face-to-face interviews and questionnaires guided by the Reason’s accident causation model. Error rates were studied in the three tertiary hospitals while intervention was carried out at NHA. Interventions involved educational outreaches consisting of structured teaching and training. Data collected compared error rates pre- and post- intervention, to determine impact of the intervention. Data were analysed using descriptive and Chi-square statistics. Prescribing error rates were 24.6 ± 1.4 (UATH), 5.7 ± 1.2 (NHA) and 6.7 ± 2.3 (UCH) for out-patient prescriptions and 28.7 ± 2.3 (UATH), 26.3 ± 2.1 (NHA) and 41.0 ± 3.1 (UCH) for in-patient prescriptions. Non-inclusion of direction of use (38.1%, UATH); missing signature and/or name of prescriber (66.6%, NHA) and omitting end date of therapy (54.4%, UCH) were the commonest errors in out-patient prescriptions. The most common in-patient prescribing error was missing end date of therapy: 71.3% (UATH), 65.9% (NHA) and 86.0% (UCH). The highest proportion of medications was ordered at admission: 57.3% (UATH), 44.3% (NHA) and 44.7% (UCH) while time of discharge was associated with the highest error rates of 37.8% (UATH), 58.6% (NHA) and 80.8% (UCH). Severity of prescribing error rates for in-patients was 4.9% (UATH), 2.8% (NHA) and 1.3% (UCH). Prescriptions involving antimicrobials contained the highest prescribing UNIVERSITY OF IBADAN LIBRARY iii errors 53.8% (UATH), 37.9% (NHA), and 36.3% (UCH). Risk factors identified in error causation included organisational (91.0%), environment (50.0%), individual (45.0%), task (45.0%) and team (36.0%) factors. Absence of self-awareness of errors and organisational factors identified included inadequate training and experience and absence of reference materials. Defences against errors, particularly pharmacists’ involvement, were deficient. There was no change in overall error rates 5.8%, pre- and post- intervention (p = 0.98). However, there were reductions in drug-drug interactions 1.2% to 0.4% (p<0.001), omission of drug route 0.3% to 0.1% (p<0.001) and ambiguous orders 0.2% to 0.0% (p<0.001) at the NHA. Prescribing errors were common in the 3 facilities resulting from writing prescriptions that lacked details and slips in attention. Majority of the errors, though of minor severity, had potential of causing harm. Continuing prescriber education and training will likely result in error reduction. Pharmacists’ involvement in prescribing error prevention should be an on-going process. Key words: Prescribing errors, Reason’s accident causation model, In- and out-patients. Word count: 500 Description: A Thesis in the Department of Clinical Pharmacy and Pharmacy Administration Submitted to the Faculty of Pharmacy in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY of the UNIVERSITY OF IBADAN

Evaluation of freeze-dried pregelatinized Chinese yam (Dioscorea oppositifolia) starch as a polymer in floating gastroretenive metformin microbeads.

2018-10-22T11:43:27Z

Title: Evaluation of freeze-dried pregelatinized Chinese yam (Dioscorea oppositifolia) starch as a polymer in floating gastroretenive metformin microbeads. Authors: Okunlola, A.; Patel, R. P.; Odeku, O. A. Abstract: Pregelatinized Chinese yam (Dioscorea oppositifolia) starch has been evaluated as a polymer for the formulation of floating gastroretentive beads for the controlled delivery of metformin hydrochloride. Floating microbeads were prepared by the ionotropic gelation method using a blend of modified Chinese yam starch and sodium alginate at different ratios. Sodium bicarbonate was added as a gas-generating agent. The floating microbeads were characterized by SEM, DSC, FTIR analyses and the drug entrapment efficiency and floating ability was evaluated. Drug release was investigated using in vitro dissolution test and the results were fitted to various kinetic models to determine the mechanism(s) of release. Spherical, discrete and free flowing microbeads were obtained from the modified starch-alginate blends. Minimum lag time (< 20 s) was observed for the floating microbeads containing starch and buoyancy was maintained for 12 h. The release of MET from the floating microbeads appeared to be controlled by varying the starch to alginate polymer ratio. In general, the formulations followed diffusion and erosion mechanisms of drug release. The results suggest that modified Chinese yam starch-sodium alginate blend can be useful for the formulation of floating gastroretentive system for metformin hydrochloride

Flow, compaction and tabletting properties of co-processed excipients using pregelatinized ofada rice starch and HPMC

2018-10-22T11:13:16Z

Title: Flow, compaction and tabletting properties of co-processed excipients using pregelatinized ofada rice starch and HPMC Authors: Okunlola, A. Abstract: The growing popularity of direct-compression process necessitates an ideal filler–binder that can substitute two or more excipients. Pregelatinization of starches significantly improves swelling and flow properties but produces tablets with low mechanical strength. When used as a binder in many tablet formulations, hydroxyl propyl methyl cellulose (HPMC) imparts mechanical strength but because of its poor flow during high speed tablet manufacturing, granulation of HPMC-based formulations is required prior to compaction. Directly-compressible co-processed excipients were developed utilizing pregelatinized starch of the indigenous Ofada rice starch (Oryza glaberrima Steud Family Poaceae) and HPMC. Co-processed excipients of various combinations of pregelatinized Ofada rice starch and HPMC K15M (15cps) were prepared using a co-fusion method (97.5:2.5; 95:5; 92.5:7.5; 90:10; 85:15; 80:20). The flow and compaction properties of the co-processed excipients, as well as, individual excipients were evaluated using density, Hausner ratio, Carr’s index, angle of repose, angle of internal friction, the Kawakita model, consolidation index and rate. Aceclofenac tablets were formulated using direct compression with starch, HPMC and specific co-processed excipients as filler-binders. Pregelatinization produced starch with larger granules and improved flow characteristics. FTIR spectra of the co-processed excipients confirmed absence of any chemical interaction. The angle of repose, Hausner ratio, Carr’s index, angle of internal friction indicated that flow properties improved with increasing starch content of the co-processed excipients. Kawakita plots, consolidation index and consolidation rate demonstrated cohesiveness while compressibility and rate of packing were enhanced. Aceclofenac tablets containing co-processed excipients exhibited a crushing strength ≥ 66.03 ± 1.58 MNm-2; friability ≤ 1%; disintegration time ≤ 10.75 ±3.10 minutes and dissolution time (t80) ≤ 30.00 ± 3.07 minutes. The co-processed excipients of pregelatinized Ofada rice starch and HPMC could be cheaper alternatives to other synthetic excipients used in direct compression of tablets assuming the starch would meet all compendial specifications.