Community-Based Surveillance of Antimicrobial Use and ...

5. Brits, South Africamost prevalent mechanism of resistance. Only 2% were non‐susceptible to fluoroquinolonesand 4.5% to ceftriaxone. Of the six ceftriaxone‐resistant isolates tested for extended‐spectrumβ‐lactamase (ESBL) production, one was positive.Table 5.1: Antimicrobial resistance among E. coliNo. tested No. resistant % resistantAmpicillin 212 139 65.6AmoxClav 211 35 16.6Cefuroxime 211 126 59.7 (includes 45.9% intermediate)Ceftriaxone 202 9 4.5Cotrimoxazole 210 109 51.9Gentamicin 212 13 6.1Fluoroquinolones 211 4 1.9Chloramphenicol 48 5 10.4Nitrofurantoin 209 12 5.7A large number of isolates tested intermediate for cefuroxime, as is depicted in Figure 5.1. Apossible reason for this is that the interpretive break‐points were close to the zone diametersof wild type E. coli in the area.Fig. 5.1: Annual percentage AMR rates among E. coli (April 2004 to March 2005)100% resistance806040IntermediateResistant200Ampi AmCl Cefur Ceftx Cotrim Genta Flquin Chloro Nitfur5.3.1.1 Trends in AMR over timeGiven the small number of isolates obtained, analysis of monthly trends could only beattempted in relation to susceptibility to ampicillin and cotrimoxazole, as shown in Figure5.2. On a quarterly basis, variability in susceptibility to these two ABMs was not seen overthe duration of the pilot study (Figure 5.3).59