Browsing by Author "Kumudunie, W.G.M."

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Comparison of four low-cost carbapenemase detection tests and a proposal of an algorithm for early detection of carbapenemase-producing Enterobacteriaceae in resource-limited settings
(Public Library of Science, 2021) Kumudunie, W.G.M.; Wijesooriya, L.I.; Wijayasinghe, Y.S.
ABSTRACT: Rapidly progressing antibiotic resistance is a great challenge in therapy. In particular, the infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are exceedingly difficult to treat. Carbapenemase production is the predominant mechanism of resistance in CRE. Early and accurate identification of carbapenemase-producing carbapenem-resistant Enterobacteriaceae (CP-CRE) is extremely important for the treatment and prevention of such infections. In the present study, four phenotypic carbapenemase detection tests were compared and an algorithm was developed for rapid and cost-effective identification of CP-CRE. A total of 117 Enterobacteriaceae (54 CP-CRE, 3 non-CP-CRE, and 60 non-CRE) isolates were tested for carbapenemase production using modified Hodge test (MHT), modified carbapenem inactivation method (mCIM), Carba NP test (CNPt), and CNPt-direct test. The overall sensitivity/specificity values were 90.7%/92.1% for MHT, 100%/100% for mCIM, 75.9%/100% for CNPt, and 83.3%/100% for CNPt-direct. OXA-48-like enzymes were detected with 93.2% sensitivity by MHT and >77.3% sensitivity by two Carba NP tests. MHT could only detect half of the NDM carbapenemase producers. CNPt-direct exhibited enhanced sensitivity compared to CNPt (100% vs 25%) for detection of NDM producers. Considering these findings we propose CNPt-direct as the first test followed by mCIM for rapid detection of CP-CRE. With this algorithm >80% of the CP-CRE could be detected within 24 hours from the time the sample is received and 100% CP-CRE could be detected in day two. In conclusion, mCIM was the most sensitive assay for the identification of CP-CRE. CNPt-direct performed better than CNPt. An algorithm consisting CNPt-direct and mCIM allows rapid and reliable detection of carbapenemase production in resource-limited settings.
Comparison of Three Carbapenemase Producing Enterobacteria (CPE) Detection Methods
(19th Conference on Postgraduate Research, International Postgraduate Research Conference 2018, Faculty of Graduate Studies,University of Kelaniya, Sri Lanka, 2018) Kumudunie, W.G.M.; Wijayasinghe, Y.S.; Wijesooriya, W.R.P.L.I.; Sunil-Chandra, N.P.; Namalie, K.D.
Introduction: The emergence of carbapenem resistant enterobacteria (CRE) is a critical and growing health threat, causing a failure of almost all the available antibiotics and limiting the effective therapeutic options. CRE has been reported all over the world including Sri Lanka. The carbapenem resistance in enterobacteria is mainly occurred due to the production of carbapenemases, the carbapenem inactivating enzymes. Therefore, accurate and timely detection of CPE is an important aspect to streamline the empiric antibiotic therapy. In this study, three CPE detection methods namely, Carba NP-rapid biochemical test, modified carbapenem inhibition method (MCIM) and modified Hodge test (MHT) were compared for the detection of CPE. Carba NP test is a rapid biochemical test that requires 2 hours or less. However, both MCIM and MHT require incubation of 18 – 24 hours. Objective: To compare theCarba NP-rapid biochemical test with the MCIM and MHT for the detection of CPE. Methodology: Fifty-eight clinically significant CRE isolates were recovered from clinical specimens from patients attended to North Colombo Teaching Hospital (NCTH)during December 2017 – February 2018. Antibiotic sensitivity testing for the screening of CRE was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Enterobacteria, resistant to at least one carbapenem antibiotic were considered as CRE. Carba NP test, MCIM and MHT were carried out for CRE isolates according to the CLSI guidelines. Statistical analysis was done using R programming language (level of significance P<0.05). Results: Of 58 CRE, 94.82% (55/58) were confirmed as CPE via both MCIM and MHT while 77.58% (45/58) were revealed as CPE by Carba NP test. There was a significant reduction of CPE detection by Carba NP method compared to MCIM and MHT(P=0.007). Conclusion: Of the three CPE detection methods, sensitivity was higher in MCIM and MHT compared to Carba NP – rapid biochemical test. Acknowledgement: Financial assistance by National Research Council, Sri Lanka (NRC 17-055) is acknowledged.
Epidemiology of multidrug-resistant Enterobacteriaceae in Sri Lanka: First evidence of bla KPC harboring Klebsiella pneumoniae.
(Elsevier., 2020) Kumudunie, W.G.M.; Wijesooriya, L.I.; Namalie, K.D.; Sunil-Chandra, N.P.; Wijayasinghe, Y.S.
BACKGROUND: Extended-spectrum β-lactamase producing Enterobacteriaceae (ESBL-PE) and carbapenem-resistant Enterobacteriaceae (CRE) are disseminated worldwide posing a serious public health concern. Although, the presence of ESBL-PE and CRE in Sri Lanka has been reported, the prevalence is unknown. This study aimed to provide up-to-date epidemiological data on multidrug-resistant Enterobacteriaceae and to characterize the molecular determinants of carbapenemase-producing Enterobacteriaceae (CPE) in Sri Lanka.METHODS: A prospective cross-sectional study was conducted at a tertiary care hospital in Sri Lanka between December 2017 and February 2018. ESBL-PE and CRE were identified by disc diffusion method. Carbapenemase production was determined by carbapenem inactivation method and the presence of selected carbapenemase genes were detected by PCR. RESULTS: Five hundred and ninety-three Enterobacteriaceae were isolated from variety of clinical samples. Overall prevalence of ESBL-PE and CRE were 26.0% (n = 154) and 9.6% (n = 57), respectively. The highest rate of ESBL-PE (30.8%) was found in urine samples, while the highest occurrence of CRE (20.8%) was seen in respiratory specimens. The most common CRE species identified was K. pneumoniae (n = 46, 80.7%), followed by C. freundii (n = 4, 7.0%), E. coli (n = 3, 5.3%), P. rettgeri (n = 2, 3.5%), E. cloacae (n = 1, 1.7%), and K. aerogenes (n = 1, 1.7%). Carbapenemase production was observed in 54 (94.7%) of CRE isolates. Fifty eight carbapenemase encoding genes were identified in 54 CPE. The most prevalent carbapenemase gene was blaOXA-48-like (n = 48, 88.9%), followed by blaNDM (n = 8, 14.8%), and blaKPC (n = 2, 3.7%). CONCLUSIONS: This study reports an alarming rate of CRE and the emergence of blaKPC harboring K. pneumoniae in Sri Lanka. The need for preventive measures is highlighted to limit the spread of these difficult-to-treat bacteria in the country. KEYWORDS: Carbapenem resistance; Carbapenemase; ESBL; Enterobacteriaceae; KPC; Sri Lanka.
Molecular characterization of carbapenemase producing enterobacteria (CPE) isolated from a tertiary care teaching hospital in Sri Lanka and validation of a rapid CPE detection protocol
(University of Kelaniya, Sri Lanka, 2021) Kumudunie, W.G.M.
INTRODUCTION: The emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE) is in dramatic increase, resulting in failure of almost all the available antibiotics and hence limit the effective therapeutic options. Therefore, accurate and timely detection of carbapenemase-producing enterobacteria (CPE) is essential to streamline the optimum antibiotic therapy. This study was carried out to determine the current status of CRE in Sri Lanka and to evaluate the performances of CPE detection methods. METHODOLOGY: A cross-sectional study was conducted at Colombo North Teaching Hospital during 2017-2018. Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) and CRE were identified by the disc diffusion method. CRE isolates were identified up to species level using a rapid identification kit. Four CPE detection methods, namely Carba NP test (CNPt), CNPt-direct, modified carbapenem inhibition method (mCIM), and modified hodge test (MHT) were evaluated. The genetic background of CPE was determined by PCR. RESULTS: The estimated overall prevalence of ESBL-PE and CRE were found to be 26.0% and 9.6%, respectively. The highest prevalence of ESBL-PE and CRE were found amongst uropathogenic (30.8%) and respiratory infections producing (20.8%) Enterobacteriaceae, respectively. K. pneumoniae (80.7%), E.coli (5.3%), C.freundii (7.0%), P. rettgeri (3.5%), E. cloacae (1.7%), and E. aerogenes (1.7%) were identified in CRE cohort. OfCRE, 94.7% were found to be CPE. The carbapenemase encoding genes detected were of blaKPc, blCINDM. and blaoXA-48-Iike and, blaoXA-48-Iike (88.9%) was the most prevalent. The overall sensitivity and specificity of CPE detection tests were as; MHT-90.7%, 92.1%, mCIM- 100%, 100%, CNPt-75.9%, I 00%, and CNPt-direct-83.3%, 100%, respectively. Only amikacin showed reasonable sensitivity (>50%) for CRE among the routine antibiotic panel whereas a higher level of susceptibility was noted for fosfomycin (92.9%), ceftazidime-avibactam (85.9%), and colistin (92.9%). CONCLUSION: K pneumoniae was the most prevalent CRE species. Carbapenemases production was the major resistance mechanism in CRE and b/aoXA-48-like was the most prevalent gene type. The first occurrence of blaKPc was recognized in Sri Lanka. MCIM and MHT had higher sensitivity compared to both CNP tests for the detection of CPE. However, when a prompt decision is needed, CNP tests can be a viable option since their results can be obtained within two hours.