Acinetobacter Outbreaks: Experience from a Neurosurgery Critical Care Unit. Jumoke Sule Consultant Microbiologist 19 May 2010

Transcription

1 Acinetobacter Outbreaks: Experience from a Neurosurgery Critical Care Unit Jumoke Sule Consultant Microbiologist 19 May 2010

2 Epidemiology of Acinetobacter spp At least 32 different species Recovered from soil, water, food, sewage, animals, humans A. baumannii is a hospital adapted strain Berlau et al, % of 192 healthy volunteers with Acinetobacter spp on skin Only one volunteer colonised with A. baumannii complex Most were A. lwoffii (61%), Acinetobacter genospecies 15BJ (12.5%), A. radioresistens (8%)

3 UK Epidemiology Late 2003 end referrals of Acinetobacter sp to HPA 419 referrals of carbapenem-resistant A. baumannii from 40 hospitals OXA-23 clone 1 Multi-drug resistant- susceptible only to colistin and tigecycline Two other epidemic clones in circulation (SE, OXA-23 clone 2)

4 Addenbrooke s Hospital, Cambridge

5 Outbreak of MDR Acinetobacter baumannii OXA-23 clone 1 at Addenbrooke s Hospital Enoch et al, 2008 November 05-May patients 16 on Neurosurgery critical care unit (NCCU) 3 on Intensive care unit Mean age 52y (18-82y) Six female (31.6%) 10 (53%)infected patients 5 respiratory infections 4 bacteraemias 1 ventriculitis 8 (42%) patients died Environmental contamination Sonosite machine Procedure s trolley Blood gas room Drug cupboard Two computer keyboards Air extract vent

6 NCCU -Time line Acinetobacter patients by date of 1st isolate Ward closed 2 Closed Opened 1 no. of cases 0 13/11/05 27/11/05 11/12/05 25/12/05 08/01/06 22/01/06 05/02/06 19/02/06 05/03/06 19/03/06 02/04/06

7 NCCU Outbreak Black bed indicates bed space at detection Grey Bed indicates bed space of index case Black lines indicate physical barriers

8 Infection control precautions Phase 1 (6 NCCU patients; Days 1-20): Routine infection control measures Isolation of affected patients Phase 2 (0 NCCU patients / 2 ICU patients; Days 20-36): Partial ward closure Physical barrier to separate new from contact patients Dedicated nursing and medical staff for each side Enhanced infection control precautions Full barrier precautions (gowns) Thorough environmental cleaning with hypochlorite Designation of cleaning responsibilities Education, training, management protocols No transfers between critical care units Patient and environmental screening Phase 3 (10 NCCU patients / 1 ICU patient; Days ) Terminal and steam clean of bed spaces Patient and environmental screening including extract vents Monthly cleaning of extract vents (Days )

9 Palabiyikoglu et al, JHI;2006

10 Role of environmental cleaning in Denton et al, 2004 outbreak control 19 patients with Acinetobacter (Neuro ICU) 7 cases first month 12 further cases in 13mths 53% of environmental samples positive Environmental cleaning with hypochlorite Significant correlation between number of environmental swabs and number of positive patients in the same month (P=0.004)

11 Challenges to control Lapses in infection control precautions Acinetobacter and new MRSA cases on NCCU No. of cases Nov-05 Dec-05 Jan-06 Feb-06 Mar-06 Month Acinetobacter MRSA

12 Challenges to control Costs Laboratory workload, overtime payments over Xmas bank holiday Enhanced cleaning, deep cleans and PPE Staffing issues Lack of clear designation of cleaning responsibilities between medical, nursing and domestic staff Increased staff absences and use of bank nursing staff & low morale due to staff fear Patient issues Long stay Acinetobacter-positive patients Delayed discharges due to lack of ward side rooms Delayed rehabilitation System/Admin Working at about 98% bed occupancy Some level 3 beds closed Cancellation of some elective procedures

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14 A. baumanii OXA-23 Clone 1 Colistin Aminoglycosides

15 New outbreak of Oxa-23 MDR A. baumannii in March 2008 Nine cases between March and August th March 2 nd April Cluster of 5 cases 2 nd -9 th June HDU windowsill and extract grill swabs positive 7 th July 4 th August Extensive environmental cleaning on NCCU Cleaning of extract air ductal system

16 Cleaning of NCCU ventilation system

17 OXA-23 clone 1 outbreaks /6

18 Summer 2009 cluster of susceptible Acinetobacter spp Acinetobacter spp. from NCCU Patients in No. of Patients st Patient Isolate All isolates were susceptible to co-amoxiclav, ciprofloxacin, gentamicin, amikacin, meropenem and colistin Susceptibility to ampicillin, cefotaxime, ceftazidime, aztreonam and septrin was 13%, 6%, 6%, 6%, 94%

19 Seasonal variation of Acinetobacter infections McDonald et al, 1999 Acinetobacter spp. from NCCU Patients in No. of Patients NCCU 1st Patient Isolate 1 0 January February March April May June July August September October November December

20 Other Acinetobacter spp sent for typing in autumn 2009/ winter 2010 Isolate Date of isolation Identification PFGE

21 Identification of Acinetobacter spp Phenotypic methods are problematic DNA-DNA hybridisation is the gold standard Bouvet and Grimont, 1986 Amplified Restriction Length Polymorphysism (AFLP) Amplified ribosomal DNA restriction analysis (ARDRA) Vaneechoutte et al, 1995 Recently described methods rpob sequence analysis La Scola et al, 2006 Multilocus PCR and electrospray ionisation mass spectrometry (PCR/ESI-MS) Ecker et al, 2006 A. baumannii detection by PCR of DNA encoding bla OXA-51-like genes Turton et al, 2006

22 Acinetobacter genomic specie 3 Falls within A. calcoaceticus-a. baumannii complex Cannot be distinguished from A. baumannii complex by routine phenotypic tests Isolated from water, soil, vegetables and human skin Increasingly reported as a cause of nosocomial infection in recent literature van den Broek et al,2006 Boo et al, 2009 Turton et al, 2010 Phylogenetic relationship of Acinetobacter spp from analysis of conserved positions in the efp housekeeping gene by PCR-MS Ecker et al, 2006

23 Take Home Messages Patient isolation and enhanced environmental cleaning play an important part in the control of Acinetobacter outbreaks Molecular identification of Acinetobacter spp is important to increase our understanding of the epidemiology and infection control Acinetobacter spp other than A. baumannii will become increasingly important in the etiology of nosocomial infections