Implications for Resistance Management

One of the most commonly used resistance management strategies involves rotating or mixing products from different classes based on modes of action and, where there are multiple applications per year, alternate products of different classes. This assumes a reduction in the frequency of the resistant genotype 

It is important that the pest or vector populations are monitored for resistance and the effectiveness of the control pesticide is monitored. In the event of a control failure that can be linked with resistance, it is important that the pest is not re-sprayed with an insecticide from the same class. Our data suggest a difference in the development rate of the susceptible and resistant strains at higher temperatures. This difference may be exploited in an attempt to control and prevent the spread of resistance in the population. 

There are few examples of thorough studies looking at the fitness costs associated with insecticide resistance. Modeling predicts resistance to be costly but makes assumptions which, in the case of DDT-R in Drosophila, are not accurate. Resistance genes are assumed not to approach fixation in natural populations and the observed frequency is assumed to be the net result of the selective advantage in the presence of selection and its cost in the absence of selection. DDT-R in Drosophila, however, is a single mutation which has spread globally and is now foimd to be fixed in populations outside of East Africa. 

1 WHO (2005). Frequently asked questions on DDT use for disease vector control, WHO/HTM/RBM/2004.54. 

2 UNEP (2001). Stockholm Convention on Persistent Organic Pollutants (POPs), UNEP/Chemicals/2001/3.50. 

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Sablon E, Shapiro F, Zoulim F. Early detection of hepatitis B dmg resistance implications for patient management. Expert Rev Mol Diagn 2003 3 535-547. 

Anonymous (1996) Drug resistance in cytomegalovirus current knowledge and implications for patient management.. /. Acquir. Immune Defic. Syndr. Hum. Retrovir. 12, S1-SS22. 

Eckardt KU. Anaenua of critical illness— implications for understanding and treating rHuEPO resistance. Nephrol Dial Transplant 2002 17 48-55. Rudis M, Jacobi J, Hassan E, Dasta J. Managing anemia in the critically ill patient. Pharmacotherapy 2004 24 229-247. 

Some limitations and problems of MIC testing are academic in nature, whereas others may have important implications for the clinician s everyday management of patients with serious infections. For example, because the MIC only represents the concentration of antimicrobial that is needed to inhibit visual growth of the most resistant cells within the tested bacterial population, there actually may be small numbers... 

Practical implications of a full elucidation of biochemical bases of insect resistance in plants are tremendous. Identification of the chemicals that confer resistance or susceptibility, and study of their inheritance in crop plants, would greatly improve breeding for resistant varieties. If resistance involves more than one defense chemical, it may be possible to develop a relatively stable type of resistance since pests are not likely to overcome sensitivity to several substances simultaneously. It would also open new avenues for manipulation of insect behavior for use in pest management programs. 

M. E. Mulligan, H. C. Standiford and C. A. Kauffman, Methicillin-resistant Staphylococcus aureus a consensus review of the microbiology, pathogenesis, and epidemiology with implications for prevention and management. Am. J. Med., 1993, 94, 313-328. 

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