A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, South Africa in partial fulfilment of the requirements for the Masters in Medicine in the branch of Public Health Medicine
Johannesburg, 6 November 2014 / Objective: New Delhi metallo-β-lactamase (NDM)-producing Gram-negative bacteria have spread globally and pose a significant public health threat. There is a need to better define risk factors and outcomes of NDM-1 clinical infection. We assessed risk factors for nosocomial infection with NDM-1-producers and associated in-hospital mortality.
Methods: A matched case-control study was conducted during a nosocomial outbreak of NDM-1-producers in South Africa. All patients from whom NDM-1-producers were identified were considered (n=105). Cases included patients admitted during the study period in whom NDM-1 producing Gram-negative bacteria were isolated from clinical specimens collected ≥48 hours after admission, and where surveillance definitions for healthcare-associated infections were met. Controls were matched for age, sex, date of hospital admission and intensive-care admission. Conditional logistic regression was used to identify risk factors for NDM-1 clinical infection and associated in-hospital mortality.
Findings: 38 cases and 68 controls were included. Klebsiella pneumoniae was the most common NDM-1-producer (28/38, 74%). Cases had longer mean hospital stays (44.0 vs 13.3 days; P < 0.001) and ICU stays (32.5 vs 8.3 days; P < 0.001). Adjusting for co-morbid disease, the in-hospital mortality of cases was significantly higher than controls (55.3% vs 14.7%; AOR, 11.29; P < 0.001). Higher Charlson co-morbidity index score (5.2 vs 4.1; AOR, 1·59; CI 95 % 1.15 – 2.18), more mechanical ventilation days (7.47 vs 0.94 days; AOR, 1.32; CI 95 % 1.10 – 1.59) and piperacillin/tazobactam exposure (11.03 vs 1.05 doses; AOR, 1.08; CI 95 % 1.02 – 1.15) were associated with NDM-1 infection on multivariate analysis. Cases had a significantly higher likelihood of in-hospital mortality when the NDM-1-producer was Klebsiella pneumoniae (AOR, 16.57; CI 95 % 2.12 – 129.6), or when they had a bloodstream infection (AOR, 8.84; CI 95 % 1.09 – 71.55).
Conclusion: NDM-1 infection is associated with significant in-hospital mortality. Risk factors for hospital-associated infection include the presence of co-morbid disease, mechanical ventilation and piperacillin/tazobactam exposure. Rational use of intensive care, medical devises and antibiotics are essential in reducing the transmission and emergence of NDM-1 and other drug resistance Gram-negative bacteria.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/17376 |
| Date | January 2014 |
| Creators | De Jager, Pieter |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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