A French regional epidemiological investigation on antibiotic resistance of S. pneumoniae in 1999 (Rhône-Alpes)

Abstract Objective – The authors wanted to determine the state of pneumococcus resistance in the Rhone-Alpes region, in 1999. Patients and method – One thousand eight hundred and thirteen strains of S. pneumoniae (Sp) (64.5% adults, 35.5% children) were collected by 31 clinical microbiological laboratories. Susceptibility to oxacillin of the strains (isolated in pathogenic conditions) was measured according to CA-SFM standards. The MICs of penicillin (P), amoxicillin (AMX), and cefotaxime (CTX) were determined (E-test or ATB-Pneumo gallery) for all strains resistant to penicillin G (PRP). The regional coordinating center checked the MIC and serotype of each PRP strain. Results – The prevalence of PRP (MIC > 0.06 mg/L) was 40.5%. Resistance (I + R) to ERY, TET, SXT, and C was respectively 42%, 27.4%, 37.9%, and 19.2%. Among the 9.4% of strains resistant to P (MIC > 1 mg/L), 63.3% were intermediate to AMX (0.5   2 mg/L). The multiresistance was frequent in PRP: 70.7% to ERY, 72% to TET, 45% to SXT, 32.8% to C, and only 0.4% to RIF. PRP of serotype 14 (23.8%) were the most frequent, followed by serotypes 6 (16%), 23 (15.7%), 9 (12%), 19 (11%), and 15 (2.8%). Discussion – PRP have been increasing since 1997 (29.5% vs. 40.5%), AMX-R strains are still infrequent (2%), and CTX-R strains even though rare (0.3%) are now isolated.