Deadly strain of antibiotic-resistant superbug detected
The strain is a variation of the klebsiella pneumoniae carbapenemase (KPC) outbreak at the Mid-Western Regional Hospital in Limerick in March, which affected nine patients.
The new strain, OXA-48-producing klebsiella pneumoniae, was detected in five in-patients at St Vincent’s University Hospital between March and June this year.
All five were on general surgical wards and all had undergone complex abdominal surgery. Two patients died from complications not related to infection. A third developed a bloodstream infection but was successfully treated. Two more showed no clinical sign of infection.
Dr Deirdre O’Brien, consultant clinical microbiologist at St Vincent’s, said the superbug fell into the category Carbapenem Resistant Enterobacteriaceae (CRE), a group of well-known bacteria, including E coli, that have developed resistance to powerful antibiotics. “It is much the same as regular E coli, but it has enzymes that can break down antibiotics. It can live in the gut without causing any problem but if it gets outside the gut, it can have serious implications.”
Following the detection of the first cases, St Vincent’s took a number of infection control measures including:
* The closure of three surgical wards to patient admissions, discharge or transfer.
* The extension of weekly rectal screening for CRE from patients in intensive care units to all patients on the three affected surgical wards.
* The screening of all patients who had been on any of the affected wards at the same time as the confirmed cases.
* Placing all CRE-colonised patients in single room isolation with contact precautions (long-sleeved gowns and gloves).
In addition, a deep-cleaning programme was implemented including disinfection by vaporised hydrogen peroxide, the gold standard for bio-decontamination.
The outbreak at St Vincent’s, documented in the recent edition of online scientific journal Eurosurveillance, said all cases had been in-patients on one of three adjacent surgical wards between which patients are frequently transferred. No other link between the cases was identified.
St Vincent’s has been carrying out CRE screening of intensive care patients since the end of March and of surgical patients since the end of April.
Dr O’Brien said it would be “premature to say the outbreak was over” but that there had been no new cases in the last four weeks.
No new cases of the outbreak strain that affected patients in Limerick have been detected since March 29.
Separately, the Health Service Executive’s Health Protection Surveillance Centre is carrying out a national pilot study to assess the prevalence of Carbapenem resistant Enterobacteriaceae in critical care units.
CRE became a notifiable disease in March this year and interim recommendations regarding screening were published this month.
