MATERIALS & METHODS: A total of 13,098 Enterobacteriaceae isolates from various clinical samples were sent to our laboratory between January 2011 and December 2012. Of these, 90 demonstrated reduced susceptibility to at least one carbapenem and were included in this study. Only 88 isolates were successfully subcultured on blood agar (BA). Another 2 isolates failed to grow and were excluded. Of the 88, 2 isolates had the same identification number (repetitive isolates); therefore, 1 isolate was excluded from further analyses. Only 87 isolates were subjected to molecular detection of the blaOXA-48 and blaOXA-181 genes by polymerase chain reaction.
RESULTS: Eighty-seven non-repetitive isolates grew following subculture on BA. Of these, 9 (10.34%) were positive for OXA-48 (7 Klebsiella pneumoniae, 2 Escherichia coli). Each isolate originated from different patients. All patients had a history of treatment with at least one cephalosporin and/or carbapenem prior to the isolation of OXA-48 CRE. OXA-181 was detected in one (1.15%) out of the 87 isolates; CONCLUSIONS: The prevalence of OXA-48 and OXA-181 CRE among all Enterobacteriaceae isolates in our institution is 0.069% and 0.008%, respectively. Nevertheless, our findings suggest that OXA-48 and OXA-181 carbapenemases appear to be important and possibly under-recognised causes of carbapenem resistance in Malaysia.
METHODS: This is a retrospective case-control study (ratio 1:1) where a patient with CRE infection or colonisation was matched with a control. The control was an individual who tested negative for CRE but was a close contact of a patient testing positive and was admitted at the same time and place. Univariate and multivariate statistical analyses were done.
RESULTS: The study included 154 patients. The majority of the CRE was Klebsiella species (83%). From univariate analysis, the significant risk factors were having a history of indwelling devices (OR: 2.791; 95% CI: 1.384-5.629), concomitant other MDRO (OR: 2.556; 95% CI: 1.144-5.707) and hospitalisation for more than three weeks (OR: 2.331; 95% CI: 1.163-4.673). Multivariate analysis showed that being unable to ambulate on admission (adjusted OR: 2.345; 95% CI: 1.170-4.699) and antibiotic exposure (adjusted OR: 3.515; 95% CI: 1.377-8.972) were independent predictors. The in-hospital mortality rate of CRE infection was high (64.5%). CRE acquisition resulted in prolonged hospitalisation (median=35 days; P<0.001).
CONCLUSION: CRE infection results in high morbidity and mortality. On top of the common risk factors, patients with mobility restriction, prior antibiotic exposures and hospitalisation for more than three weeks should be prioritised in the screening strategy to control the spread of CRE.