1. Microbiology and Infection prevention and control
Effective management of Carbapenem-resistant Acinetobacter Baumanii (CRAB) outbreak (OXA 23/51) in a teaching hospital
Lee Reed, Deborah Gnanarajah, Justine Haliwell, Rebecca Turner, Milind Khare
Introduction
Acinetobacter is a Gram negative organism that is ubiquitous in the environment and is naturally resistant to many antibiotics.  It can survive desiccation so it is ideally suited to survive in the environment. Carbapenem-resistant Acinetobacter Baumanii (CRAB) presents a serious therapeutic and infection, prevention and control challenge.
Background
In Royal Derby Hospital, 12 patients have been identified since November 2016; with cases (predominantly) in specialities Diabetes, Renal and Vascular. Splint workshop has also been identified as an area where these patients will have been seen. All patients have the same antibiotic resistant patterns and all are carbapenamase producer(CPE) oxa 23/51. VNTR testing has identified 6 patients as linked; and 12 patients had identical phage type deri50ac-1(see Table 1). A further 3 patient VNTR results are pending. 3 patients have a unique phage type and are not linked to this cluster.
Method and Results
CHROMID™ CARBA SMART chromogenic agar (figure 1) was used as screening method.
Environmental swabbing
Environmental swabbing has been undertaken from various locations on the diabetic foot clinic, renal dialysis unit, endocrinology and renal ward. Vascular ward environment swabbing was not done.
25 environmental swabs were taken on renal dialysis unit – all negative for Acinetobacter baumanii.
21 environmental swabs were taken on Renal ward – all negative for Acinetobacter baumanii.
20 environmental swabs were taken on the diabetic foot clinic – 1 swab identified CRAB (underside of a patient couch). This positive environmental swab has the same antibiotic resistance pattern; oxa 23/51 and VNTR testing has identified it as phage type deri50ac-1 and is linked to the same cluster.
19 environmental swabs were taken on endocrinology ward – 1 swab identified Acinetobacter baumanii (over bed light). This sample has been sent to the reference laboratory for VNTR testing to determine if this environmental sample is also linked
Environmental decontamination
Cleaning standards in diabetic foot clinic and renal dialysis have historically not always been to the required standards, but focus within these areas has resulted in an improvement. Both areas have undergone hydrogen peroxide decontamination. Equipment cleaning between patients in the diabetic foot clinic is a challenge due to the number of patients seen in the clinic. Disinfectant wipes and a cleaning regime has been introduced. A full deep clean and hydrogen peroxide of endocrinology ward and Renal ward is being arranged. Temporary closure of beds may be required to facilitate this.
Discussion
It was identified that diabetic patients requiring angiogram / angioplasty require transfer to
vascular surgical ward as part of the radiology protocol. This leads to potential contamination of multiple environments and has increased length of stay whilst waiting for beds to be available. It was agreed to scrap this protocol
It was agreed that contact tracing and patient screening would not be carried out at present, however the situation will be closely monitored and this will be considered if cases continue to be identified.
11 out of the 16 patients in the cluster have died, but cause of death did not have CRAB in any part of the death certificates. Most were colonisations in patients with multiple co-morbidities.
PHE receive notifications for CPE and carbapenamase producing pseudomonas, but not for Acinetobacter. This has been flagged to the national team.
Terminal cleans in diabetic foot clinic to be prioritised through the switch board helpdesk to prevent delays.
Utilising diabetic foot MDT and board rounds to deliver key messages. The outbreak control group is continuing surveillance and monitoring. The outbreak and control measures have been presented at Grand round as this has been particularly useful in raising awareness.
Fig 1. CHROMID™ CARBA SMART agar
Collection Date
Test National Code
PFGE
VNTR
22/08/2018
LEG SWAB
OXA 23 / 51
deri50ac-1
03/07/2018
SPUTUM
PENDING
08/05/2018
7, 18, 12, 10
30/04/2018
Nephrostomy urine
7, 18, 13, 10
06/04/2018
Aspirate L foot
16/03/2018
14/03/2018
R foot fluid
25/01/2018
24/01/2018
02/10/2017 W
15, 18, 12, 10
30/09/2017 BC
19/09/2017
11/09/2017
CP Screen
Unique
12, 16, 20, 7
25/05/2017
05/04/2017
09/11/2016
19, 18, 14, 8
21/03/2018
Environmental swab
17/04/2018
Table 1
Conclusion
So far we have managed to control spread of this infection with multi-resistant acinetobacter and we had no new case isolated after 22nd August 2018.