Acinetobacter Outbreaks: Experience from a Neurosurgery Critical Care Unit Jumoke Sule Consultant Microbiologist 19 May 2010
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, 1999 40% 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%)
UK Epidemiology Late 2003 end 2005 1600 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)
Addenbrooke s Hospital, Cambridge
Outbreak of MDR Acinetobacter baumannii OXA-23 clone 1 at Addenbrooke s Hospital Enoch et al, 2008 November 05-May 06 19 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
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
NCCU Outbreak Black bed indicates bed space at detection Grey Bed indicates bed space of index case Black lines indicate physical barriers
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 36-159) Terminal and steam clean of bed spaces Patient and environmental screening including extract vents Monthly cleaning of extract vents (Days 107-159)
Palabiyikoglu et al, JHI;2006
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)
Challenges to control Lapses in infection control precautions Acinetobacter and new MRSA cases on NCCU No. of cases 8 7 6 5 4 3 2 1 0 Nov-05 Dec-05 Jan-06 Feb-06 Mar-06 Month Acinetobacter MRSA
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
A. baumanii OXA-23 Clone 1 Colistin Aminoglycosides
New outbreak of Oxa-23 MDR A. baumannii in March 2008 Nine cases between March and August 2008 17 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
Cleaning of NCCU ventilation system
OXA-23 clone 1 outbreaks 2008 2005/6
Summer 2009 cluster of susceptible Acinetobacter spp Acinetobacter spp. from NCCU Patients in 2009 9 8 7 No. of Patients 6 5 4 3 2 1 0 1st 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%
Seasonal variation of Acinetobacter infections McDonald et al, 1999 Acinetobacter spp. from NCCU Patients in 2009 9 8 7 No. of Patients 6 5 4 3 2 NCCU 1st Patient Isolate 1 0 January February March April May June July August September October November December
Other Acinetobacter spp sent for typing in autumn 2009/ winter 2010 Isolate Date of isolation Identification PFGE
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
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
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