Bacterial recontamination of hands following handwashing and associated risk factors in rural Andhra Pradesh, India Carol Devamani
Nov 21, 2014
Bacterial recontamination of hands following handwashing and associated risk
factors in rural Andhra Pradesh, India
Carol Devamani
OverviewIntroduction
Palamaner, Andhra Pradesh, IndiaAimsFaecal Indicator Bacteria
MethodologyResultsStrengths & WeaknessesPlates Conclusion
IntroductionAims
Primary: Recontamination levels – HWWSSecondary: risk factors
Faecal Indicator BacteriaEscherichia coliEnterococcus :
Sherman’s Criteria
MethodologyCPS Agar
Urine samplesSampling Technique
Direct Finger ImpressionMain study : 14 mothers/caregiversSub-study:
cross sectional survey 122 participants
• Main study
MethodologyPhoto Archiving :
random number for each platePhoto after 24-hour incubationReading by one person of:
Number of contaminated fingers Overall colony count
Microbiological Testing of Colonies : CMC, Vellore
Data Analysis
RESULTS
Main Study
Distribution of the number of fingers contaminatedEnterococcus E. coli
5.5 3.6
05
1015
2025
Per
cent
0 100 200 300entcocolony
05
1015
20P
erce
nt
-2 0 2 4 6entcol2
020
40
60
Perc
ent
0 50 100 150 200 250ecolicolony
05
1015
20P
erce
nt
0 2 4 6 8ecolicol2
Log Colony CountEnterococcus
E.coli
2.3
1.6
Recontamination - EnterococcusFINGER COUNT
LOG COLONY COUNT
6.6
2.9
Recontamination: E.coliFINGER COUNT
LOG COLONY COUNT
3.5
1.7
Comparison between the handwashing and control arms at each time point (t-test)
Sub - Study
Effect of type of person and type of activity on number of fingers contaminated and log colony count of Enterococcus
Sub-study : Enterococcus
N
No. of fingers contaminated Log Colony Count
Difference* P value* Difference* P value*
Person
Male (reference) 23 - - - -
Female 65 1.64 0.011 0.69 0.013
Grandmother 34 0.47 0.512 0.42 0.175
Activity
None (reference) 19 - - - -
Child rearing 37 2.31
0.002 0.69 0.026
Food
preparation
12 2.47 0.014 1.31 0.008
Soil contact 24 0.81 0.286 0.16 0.559
Contact with
Agricultural
products/crops
6
0.14
0.912
0.58
0.332
Animal contact 10 1.37 0.228 0.46 0.362
Other 23 0.39 0.662 0.18 0.647
*univariate linear regression analysis
Sub-study: E.coliEffect of type of person and type of activity on number of
fingers contaminated and log colony count of Escherichia coli
N No. of fingers contaminated Log Colony Count
Difference* P value* Difference* P value*
Person
Male (reference) 23 - - - -
Female 65 0.29 0.623 0.24 0.467
Grandmother 34 0.95 0.148 0.48 0.188
Activity
None (reference) 19 - - - -
Child rearing 37 -0.14 0.834 0.27 0.464
Food preparation 12 1.41 0.163 1.23 0.031
Soil contact 24 0.87 0.269 0.45 0.181
Contact with Agricultural products/crops
6
2.49
0.083
2.15
0.006
Animal contact 10 1.66 0.105 1.15 0.016
Other 23 -0.54 0.505 -0.003 0.995
*univariate linear regression analysis
Strengths & WeaknessesStrengths WeaknessesSimplicity of Method
No further testing Only need IncubatorNo additional personnel
Small Sample SizeDifficulty identifyingReading by Single
person
Colourful India all in one Plate!
Identification: Enterococcus
Identification: E. coli
Baseline
0 hours ( post- HWWS)
0.5 hrs
1 hour
1.5 hours
ConclusionRecontamination rate very quick
Within half an hourNot useful for evaluating handwashing
campaignsBut indicates environmental exposure?
Routes of TransmissionSub-study:
Enterococcus: Food Preparation, Child rearing E.coli: Food preparation, Contact with animals,
agricultural produce/crops
Further Research
AcknowledgementsWolf Peter Schmidt – LSHTMVal Curtis and Adam Biran – LSHTMBob Aunger – LSHTMDivya Rajaraman, Kiruba Sankar, John
Kenneth St. John’s Research Institute)Mary Matthews – Christian Medical College,
Vellore
Thank you