Browsing by Author "Bamford, Colleen"

Now showing 1 - 8 of 8
  • Thumbnail Image
    Item
    Open Access
    Antibiotic stewardship ward rounds and a dedicated prescription chart reduce antibiotic consumption and pharmacy costs without affecting inpatient mortality or re-admission rates
    (Public Library of Science, 2013) Boyles, Tom H; Whitelaw, Andrew; Bamford, Colleen; Moodley, Mischka; Bonorchis, Kim; Morris, Vida; Rawoot, Naazneen; Naicker, Vanishree; Lusakiewicz, Irena; Black, John
    BACKGROUND: Antibiotic consumption is a major driver of bacterial resistance. To address the increasing burden of multi-drug resistant bacterial infections, antibiotic stewardship programmes are promoted worldwide to rationalize antibiotic prescribing and conserve remaining antibiotics. Few studies have been reported from developing countries and none from Africa that report on an intervention based approach with outcomes that include morbidity and mortality. METHODS: An antibiotic prescription chart and weekly antibiotic stewardship ward round was introduced into two medical wards of an academic teaching hospital in South Africa between January-December 2012. Electronic pharmacy records were used to collect the volume and cost of antibiotics used, the patient database was analysed to determine inpatient mortality and 30-day re-admission rates, and laboratory records to determine use of infection-related tests. Outcomes were compared to a control period, January-December 2011. RESULTS: During the intervention period, 475.8 defined daily doses were prescribed per 1000 inpatient days compared to 592.0 defined daily doses/1000 inpatient days during the control period. This represents a 19.6% decrease in volume with a cost reduction of 35% of the pharmacy's antibiotic budget. There was a concomitant increase in laboratory tests driven by requests for procalcitonin. There was no difference in inpatient mortality or 30-day readmission rate during the control and intervention periods. CONCLUSIONS: Introduction of antibiotic stewardship ward rounds and a dedicated prescription chart in a developing country setting can achieve reduction in antibiotic consumption without harm to patients. Increased laboratory costs should be anticipated when introducing an antibiotic stewardship program.
  • Thumbnail Image
    Item
    Open Access
    Bloodstream infections at a tertiary level paediatric hospital in South Africa
    (BioMed Central, 2017-12-06) Lochan, Harsha; Pillay, Vashini; Bamford, Colleen; Nuttall, James; Eley, Brian
    Background: Bloodstream infection (BSI) in children causes significant morbidity and mortality. There are few studies describing the epidemiology of BSI in South African children. Methods: A retrospective descriptive cohort study was conducted at a paediatric referral hospital in Cape Town, South Africa. The National Health Laboratory Service (NHLS) microbiology database was accessed to identify positive blood culture specimens during the period 2011–2012. Demographic and clinical details, antimicrobial management and patient outcome information were extracted from medical and laboratory records. Antibiotic susceptibility results of identified organisms were obtained from the NHLS database. Results: Of the 693 unique bacterial and fungal BSI episodes identified during the study period, 248 (35.8%) were community-acquired (CA), 371 (53.5%) hospital-acquired (HA) and 74 (10.7%) healthcare-associated (HCA). The overall risk was 6.7 BSI episodes per 1000 admissions. Escherichia coli, Staphylococcus aureus and Streptococcus pneumoniae were the most frequent causes of CA-BSI and Klebsiella pneumoniae, Acinetobacter baumanii and S. aureus were most commonly isolated in HA-BSI. On multivariable analysis, severe underweight, severe anaemia at the time of BSI, admission in the ICU at the time of BSI, and requiring ICU admission after BSI was diagnosed were significantly associated with 14-day mortality. Conclusion: This study adds to the limited literature describing BSI in children in Africa. Further studies are required to understand the impact that BSI has on the paediatric population in sub-Saharan Africa.
  • Thumbnail Image
    Item
    Open Access
    Klebsiella pneumoniae bloodstream infections at a South African children’s hospital 2006–2011, a cross-sectional study
    (BioMed Central, 2016-10-17) Buys, Heloise; Muloiwa, Rudzani; Bamford, Colleen; Eley, Brian
    Background: Klebsiella pneumoniae (KP) is a significant paediatric bloodstream pathogen in children. There is little data from Africa. In this study we describe the epidemiology of multi-drug resistant Klebsiella pneumoniae bloodstream infection (KPBSI) at Red Cross War Memorial Children’s Hospital, Cape Town, South Africa. Methods: We conducted a retrospective cross-sectional study of KPBSI from 1 January 2006 to 31 December 2011 using conventional descriptive and inferential statistical methods. Results: Of 410 hospitalised children with laboratory confirmed KPBSI, 339 (83 %) were caused by extendedspectrum β-lactamase (ESBL) producing isolates. The median age (IQR) was 5.0 (2–16) months, 212 (51.7 %) were male, 82 (20 %) were HIV-infected, and 241 (58.8 %) were moderately or severely underweight. The infection was hospital-acquired or healthcare-associated in 389 (95 %) children and community-acquired in 21 (5 %) children. Significant risk factors for ESBL-KPBSI included cephalosporin exposure in the 12 months prior to the KPBSI, adjusted risk ratio (aRR) 1.18 (95 % CI: 1.06–1.31); HIV infection, aRR 1.14 (1.04–1.25), and intravenous infusions for more than 3 days before the KPBSI, aRR 1.15 (95 % CI: 1.04–1.28). A total of 109 (26.6 %) children died within 30 days of the KPBSI, their median age was four (IQR 1–11) months. The median (IQR) time between KPBSI and death was three (1–9) days. HIV-infection, aRR 2.44(95 % CI: 1.59–3.74); skin erosions at the time of KPBSI, aRR 2.15 (95 % CI: 1.54–3.00); being in PICU at the time of the KPBSI, aRR 1.64 (95 % CI: 1.03–2.61) or needing PICU admission after developing KPBSI, aRR 1.72 (95 % CI: 1.10–2.70) were significant risk factors for death. Conclusion: ESBL-producing KP is an important cause of laboratory confirmed bloodstream infection in hospitalised children and is associated with high mortality.
  • Thumbnail Image
    Item
    Open Access
    Outbreak of multi-drug resistant Pseudomonas aeruginosa bloodstream infection in the haematology unit of a South African academic hospital
    (Public Library of Science, 2013) Mudau, Maanda; Jacobson, Rachael; Minenza, Nadia; Kuonza, Lazarus; Morris, Vida; Engelbrecht, Heather; Nicol, Mark P; Bamford, Colleen
    Objective: To describe an outbreak of multi-resistant Pseudomonas aeruginosa bloodstream infections (MRPA-BSI) that occurred in the haematology ward of a tertiary academic hospital in Cape Town, South Africa, and determine risk factors for acquisition of MRPA-BSI. METHODS: The outbreak investigation included a search for additional cases, review of patient records, environmental and staff screening, molecular typing using pulsed-field gel electrophoresis (PFGE) and Multi-locus sequencing (MLST) and a retrospective case-control study. RESULTS: Ten MRPA-BSI cases occurred in the haematology ward between January 2010 and January 2011. The case fatality rate was 80%. Staff screening specimens were negative for MRPA and an environmental source was not identified. PFGE showed that 9/10 isolates were related. MLST showed that 3 of these 9 isolates belonged to Sequence type (ST) 233 while the unrelated isolate belonged to ST260. CONCLUSION: We have described an outbreak of MRPA-BSI occurring over an extended period of time among neutropenic haematology patients. Molecular typing confirms that the outbreak was predominantly due to a single strain. The source of the outbreak was not identified, but the outbreak appears to have been controlled following intensive infection control measures.
  • Thumbnail Image
    Item
    Open Access
    Prevalence and trends of Staphylococcus aureus Bacteraemia in hospitalized patients in South Africa, 2010 to 2012: laboratory-based surveillance mapping of antimicrobial resistance and molecular epidemiology
    (Public Library of Science, 2015) Perovic, Olga; Iyaloo, Samantha; Kularatne, Ranmini; Lowman, Warren; Bosman, Noma; Wadula, Jeannette; Seetharam, Sharona; Duse, Adriano; Mbelle, Nontombi; Bamford, Colleen; Dawood, Halima; Mahabeer, Yesholata; Bhola, Prathna; Abrahams, Shareef; Singh-Moodley, Ashika
    Introduction We aimed to obtain an in-depth understanding on recent antimicrobial resistance trends and molecular epidemiology trends of S . aureus bacteraemia (SAB). METHODS: Thirteen academic centres in South Africa were included from June 2010 until July 2012. S . aureus susceptibility testing was performed on the MicroScan Walkaway. Real-time PCR using the LightCycler 480 II was done for mec A and nuc . SCC mec and spa -typing were finalized with conventional PCR. We selected one isolate per common spa type per province for multilocus sequence typing (MLST). RESULTS: S . aureus from 2709 patients were included, and 1231 (46%) were resistant to methicillin, with a significant decline over the three-year period (p-value = 0.003). Geographical distribution of MRSA was significantly higher in Gauteng compared to the other provinces (P<0.001). Children <5 years were significantly associated with MRSA with higher rates compared to all other age groups (P = 0.01). The most prevalent SCC mec type was SCC mec type III (531 [41%]) followed by type IV (402 [31%]). Spa -typing discovered 47 different spa -types. The five (87%) most common spa- types were t037, t1257, t045, t064 and t012. Based on MLST, the commonest was ST612 clonal complex (CC8) (n = 7) followed by ST5 (CC5) (n = 4), ST36 (CC30) (n = 4) and ST239 (CC8) (n = 3). CONCLUSIONS: MRSA rate is high in South Africa. Majority of the isolates were classified as SCC mec type III (41%) and type IV (31%), which are typically associated with hospital and community- acquired infections, respectively. Overall, this study reveals the presence of a variety of hospital-acquired MRSA clones in South Africa dominance of few clones, spa 037 and 1257. Monitoring trends in resistance and molecular typing is recommended to detect changing epidemiological trends in AMR patterns of SAB.
  • Thumbnail Image
    Item
    Open Access
    The Pneumococcus Urinary Antigen Test Kit: Use in the laboratory for the presumptive diagnosis of pneumococcal bacteraemia
    (2020) Tootla, Hafsah Deepa; Bamford, Colleen; Moodley, Clinton
    Introduction: Culture remains the ‘gold standard' for diagnosis of Streptococcus pneumoniae bacteraemia. Time to definitive identification using culture is 24–48 hours, and prior antibiotic therapy, the ability of S. pneumoniae to self-autolyse and its fastidious nature can yield no growth on culture. Novel detection methods for invasive pneumococcal disease include PCR and antigen tests. We evaluated using a urine antigen test directly on selected blood cultures with appropriate Gram stain results, immediately after signalling positive for the rapid identification of S. pneumoniae bacteraemia. Method: We collected 212 blood cultures that had signalled positive with an automated blood culture system, and then yielded gram-positive cocci in pairs/chains or cocci with uncertain morphological arrangement. The BinaxNOW Streptococcus pneumoniae urinary antigen test, routine culture with optochin and real time lytA PCR was performed on all samples. Diagnostic accuracy analysis (sensitivity and specificity) of the antigen test and Gram stain with gram-positive cocci in pairs was each compared to culture positivity for S. pneumoniae, PCR positivity and the composite of culture or PCR positivity for S. pneumoniae as the reference standards. Results: S. pneumoniae (Spn) was cultured in 55 samples, gram-positive organisms other than S. pneumoniae (NSpn) in 140 samples and 17 samples had no growth (NG). Grampositive cocci in pairs was predominant on Gram stain in the Spn/NG groups whilst the minority in the NSpn group. In the Spn group, all except 1 sample which was antigen positive but PCR negative, were antigen and PCR positive. In the NSpn group, antigen and PCR was negative in 123 samples, antigen and PCR positive in 1 sample and antigen positive but PCR negative in the remaining 16 samples. In the NG group, antigen and PCR were positive in 16 samples and antigen positive but PCR negative in 1 sample. Sensitivity of the antigen test compared to culture, PCR or the composite of culture or PCR was 100%. Specificity was 87-88% but increased to 93-96% when used in subsets with gram-positive cocci in pairs or clinical history compatible with respiratory illness or meningitis. Sensitivity and specificity of the antigen test when compared to Gram stain using gram-positive cocci in pairs (69%-75% and 81% respectively) were both higher. Discussion and Conclusion: Accurate and rapid diagnosis of S. pneumoniae bacteraemia is challenging with current diagnostic tools. Specificity of the antigen test is mostly limited by crossreactivity with viridans streptococci, coagulase negative staphylococci and enterococcus species, but this can be overcome if Gram stain morphology and clinical history is available. Sensitivity and specificity of Gram stain alone in predicting S. pneumoniae bacteraemia is poor and is increased with use of the antigen test. The antigen test is a useful adjunctive tool improving diagnosis and turnaround time of S. pneumoniae bacteraemia. In settings like ours, where high-level resistance, defined as minimum inhibitory concentration ≥2μg/mL to penicillin is still relatively low (~7%), rapid de-escalation to penicillin in the appropriate clinical setting would be possible with the introduction of such test and could also potentially be a suitable alternative to molecular testing for S. pneumoniae identification in samples with no growth on culture.
  • Thumbnail Image
    Item
    Open Access
    The use of molecular diagnostic methods to improve the detection of the common bacterial and viral causes of community acquired meningitis in children in South Africa
    (2015) Khumalo, Jermaine; Bamford, Colleen; Du Toit, Elloise
    With conventional methods of diagnosis, substantial overlaps are common due to an absence of the expected CSF findings clearly aligning to bacterial or viral infection. Reduced sensitivity is commonly observed chiefly due to empiric antibiotic treatment leading to bacterial culture negative results. This leads to costly hospital admissions and unnecessarily prolonged treatment for the unexplained aetiology, further compounded by routine viral diagnostics not being commonly implemented for meningitis diagnosis. We developed and validated in-house quantitative real-time (qPCR) multiplex assays to test for bacterial causes namely: Neisseria meningitidis (ctrA gene), Haemophilus influenzae (hpd gene) and Streptococcus pneumoniae (lytA gene) and viral causes namely: enterovirus (5' UTR), herpes simplex (UL30 gene) and mumps virus (Fusion protein gene). The qPCR assays were carried out on the Biorad CFX 96 real-time instrument. These validated assays were used to screen a cohort of suspected meningitis cases. The retrospective study included 300 paediatric patients aged from 60 days-12 years, over a 1-year period (November1, 2012 to November 30, 2013) with suspected meningitis presented to the outpatient departments of the Red Cross War Memorial Children‟s Hospital (RCCH) in Cape Town. Cerebrospinal fluid with abnormal chemistry and cell counts was selected and total nucleic acid was extracted with the QIAsymphony virus/bacterial DSP kit (QIAGEN, Valencia, CA). The median age of children was 19 months (IQR: 6-65 months). Among the screened 291 CSF samples, 7 (2.4%) cases Gram stain results were obtained along with relatively few cases with positive bacterial culture growth 4/291 (1.4%). Based on bacterial qPCR results, 8 (2.7%), 3 (1%) and 1 (0.3%) were positive for S. pneumoniae, N. meningitidis and H. influenzae respectively. A majority of cases were viral positives with enteroviruses being the dominant at 91/291 (31.3%) and mumps virus 3/291 (1%). No herpes simplex DNA was detected. The bacterial qPCR showed a sensitivity and specificity of 85.7% and 97.7% respectively when compared against a composite reference standard (CRS). We report an improvement with additional detected causes of bacterial meningitis and highlight the burden of the common viral causes. However, a large proportion of cases (63.6 %) have aetiology still unknown. PCR shows valuable in concluding viral aetiology in routine diagnosis.
  • Thumbnail Image
    Item
    Open Access
    Validation of a Pan-fungal polymerase chain reaction (PCR) assay for the detection and identification of medically important fungi in a diagnostic laboratory
    (2018) Ntuli, Sindile Venessa; Moodley, Clinton; Bamford, Colleen
    The laboratory diagnosis of fungal infection is complicated, based on the microscopic detection, culture isolation, and detection of serological response. In recent years, there has been an increase in the utilization of molecular diagnostic techniques for the detection and accurate identification of fungal pathogens. This was a laboratory accuracy study evaluating the performance of a selected pan-fungal PCR using 70 previously identified reference fungal isolates. The DNA yield and purity of three different DNA extraction methods was assessed, using 6 representative fungal isolates. The ZR Fungal/Bacterial DNA MicroPrep™ produced a median concentration of 17.28 ng/μl,which was significantly higher (p value = 0.0079) than the MagNA pure LC DNA Isolation Kit III and QIAamp DNA Mini Kit, which produced median yields of 11.08ng/μl and 3.54 ng/μl, respectively. The selected pan-fungal PCR was optimized PCR and successfully performed on 62 of the 70 reference isolates. A selection of 56 amplicons were submitted for DNA sequence determination. Of all the sequences queried on the NCBI and Ribosomal Development Project (RDP) databases, 95/111(86%) were concordant with the results obtained from the reference laboratory. Study findings have shown that the selected pan-fungal PCR, coupled with DNA sequence analysis is an excellent diagnostic tool for the identification of medically relevant fungi. This assay, in combination with conventional culture, is useful for the rapid and accurate identification of fungal isolates. Future work will involve evaluating the utility of this assay for the detection and identification of medically relevant fungi in deep tissue biopsies.