Carol Devamani describes her study of bacterial recontamination after handwashing with soap. The findings from her research project - conducted as part of her studies at the London School of Hygiene and Tropical Medicine - show that rural India is a highly contaminated environment.

1. Carol Devamani

2. Overview
 Introduction
 Palamaner, Andhra Pradesh, India
 Aims
 Faecal Indicator Bacteria
 Methodology
 Results
 Strengths & Weaknesses
 Plates
 Conclusion

5. Introduction
 Aims
 Primary: Recontamination levels – HWWS
 Secondary: risk factors
 Faecal Indicator Bacteria
 Escherichia coli
 Enterococcus :
 Sherman’s Criteria

6. Methodology
 CPS Agar
 Urine samples
 Sampling Technique
 Direct Finger Impression
 Main study : 14 mothers/caregivers
 Sub-study:
 cross sectional survey
 122 participants

7. • Main study

8. Methodology
 Photo Archiving :
 random number for each plate
 Photo after 24-hour incubation
 Reading by one person of:
 Number of contaminated fingers
 Overall colony count
 Microbiological Testing of Colonies : CMC, Vellore
 Data Analysis

9. RESULTS

11. Distribution of the number of fingers contaminated
Enterococcus E. coli
5.5 3.6

12. Log Colony Count
Enterococcus
20
25
20
15
2.3
15
Percent
Percent
10
10
5
5
0
0
0 100 200 300 -2 0 2 4 6
entcocolony entcol2
E.coli
60
20
15
40
Percent
Percent
10
1.6
20
5
0
0
0 50 100 150 200 250 0 2 4 6 8
ecolicolony ecolicol2

13. Recontamination - Enterococcus
FINGER COUNT
6.6
LOG COLONY COUNT
2.9

14. Recontamination: E.coli
FINGER COUNT
3.5
LOG COLONY COUNT
1.7

15. Comparison between the handwashing and control arms at each
time point (t-test)

17. Sub-study : Enterococcus
Effect of type of person and type of activity on number of fingers
contaminated and log colony count of Enterococcus
No. of fingers contaminated Log Colony Count
N
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 12 2.47 0.014 1.31 0.008
preparation
Soil contact 24 0.81 0.286 0.16 0.559
Contact with
Agricultural 6 0.14 0.912 0.58 0.332
products/crops
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

18. Sub-study: E.coli
Effect of type of person and type of activity on number of fingers
contaminated and log colony count of Escherichia coli
No. of fingers contaminated Log Colony Count
N
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 6 2.49 0.083 2.15 0.006
products/crops
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

20. Strengths & Weaknesses
Strengths Weaknesses
 Simplicity of Method  Small Sample Size
 No further testing  Difficulty identifying
 Only need Incubator  Reading by Single person
 No additional personnel

21. Colourful India all in one Plate!

22. Identification: Enterococcus

23. Identification: E. coli

24. Baseline

25. 0 hours ( post- HWWS)

26. 0.5 hrs

27. 1 hour

28. 1.5 hours

29. Conclusion
 Recontamination rate very quick
 Within half an hour
 Not useful for evaluating handwashing campaigns
 But indicates environmental exposure?
 Routes of Transmission
 Sub-study:
 Enterococcus: Food Preparation, Child rearing
 E.coli: Food preparation, Contact with animals, agricultural
produce/crops
 Further Research

30. Acknowledgements
 Wolf Peter Schmidt – LSHTM
 Val Curtis and Adam Biran – LSHTM
 Bob Aunger – LSHTM
 Divya Rajaraman, Kiruba Sankar, John Kenneth
St. John’s Research Institute)
 Mary Matthews – Christian Medical College, Vellore

31. Thank you