Biswaroop Chatterjee

Abstract

Context: Alcohol-based hand-rubs (ABHR) are widely used for hand hygiene. The presence of many brands with different formulae and prices complicates product selection. Aim: To demonstrate differences in antibacterial efficacy, if any, among ABHRs available in India. Objectives: 1) Evaluate and compare six common Indian brands of ABHRs, and also the ABHR formulation recommended by the WHO, against 60% iso-propanol. 2) Compare prices of Indian brands Methods and Material: Hands were artificially contaminated with Escherichia coli, ATCC® 25922TM strain. Bacterial load on hands was tested before and after ABHR use to assess efficacy. Testing technique was a modification of the EN 1500 method of the European Committee for Standardization. Statistical analysis used: ANOVA. Results: Three products were as effective as 60% iso-propanol, two were better and one was actually worse. Branded ABHR were five to six times more expensive than 60% isopropanol. Conclusions: Several expensive brands of ABHR were no better than 60% iso-propanol. Additional CHG made no difference to ABHR efficacy. Key Messages: Four of the six Indian ABHR brands tested were no better than 60% iso-propanol, the reference standard handrub of the European Committee for Standardization. CHG did not demonstrate better antibacterial efficacy in the 30 seconds of hand rubbing provided ABHRs were tested with CHG neutralizing products to eliminate the carry-over effect. Keywords: Alcoholbased hand rub (ABHR), Chlorhexidine gluconate, Efficacy, Price India.

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Abstract

Introduction: Despite limitations, the Widal test is widely used in resource-constrained settings because it is fast, inexpensive and user-friendly. Therefore, efforts continue to improve its diagnostic utility. Aims: Using 2-mercaptoethanol (2-ME) to detect the IgM fraction of total agglutinins detected by the Widal test in the serum of febrile patients. Materials and Methods: Single serum specimens were collected from 333 patients presenting to our hospital with fever. One aliquot of serum was tested by standard Widal test; a positive result was defined as simultaneous elevation of ‘O’ and 'H' titres to 1:80 or above. A second aliquot was simultaneously tested by a modified Widal test in which serum was diluted in isotonic saline with added 2-ME (0.12M) instead of in plain isotonic saline. Differences in titre between the two versions of Widal test were noted. A four-fold or greater reduction in titre upon testing with 2-ME, was considered evidence of specific IgM. Results: Standard Widal test was positive in 55 (16.5%) out of 333 patients. A ?4-fold reduction of ‘O’ titre in modified Widal test was found in 38 (69.1%) out of 55 cases, indicating the presence of specific IgM. A similar reduction of 'H' titre was seen in only 6 (11%) out of 55 cases. Conclusion: Simultaneous use of standard Widal test and modified Widal test with 2-ME allows the detection of specific IgM at a low cost. This can increase the diagnostic utility of the Widal test. Keywords: Acute febrile illness, Typhoid fever, Serology, IgM, Laboratory diagnosis.

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