The second European collaborative study on the frequency of antimicrobial resistance inHaemophilus influenzae

Abstract

In the second European survey of the prevalence of antimicrobial resistance in Haemophilus influenzae, 2529 clinical isolates collected in 1988/89 from 78 laboratories in nine countries (Austria, Belgium, Federal Republic of Germany, France, Italy, The Netherlands, Spain, Switzerland, United Kingdom) were examined. Of these, 23.8% were type b strains. The overall rate of beta-lactamase production was 9.1%, being slightly higher in type b isolates (10.5%) compared to non-type b isolates (8.6%). The MICs of six antimicrobials (ampicillin, cefaclor, chloramphenicol, erythromycin, tetracycline, and cotrimoxazole) were determined by an agar dilution procedure at a single central laboratory. The proportion of isolates resistant to the antimicrobials varied considerably amongst the individual countries. The highest incidence of resistance to all six drugs was observed in strains collected in Spain, whereas resistance was rarely encountered among strains isolated in Austria and the FRG. Resistance to ampicillin (MIC greater than or equal to 4 mg/l) among strains that lacked beta-lactamase activity was uncommon (0.3%). Based on the NCCLS Haemophilus influenzae breakpoints, the rates of susceptibility and resistance to cefaclor, chloramphenicol, tetracycline, and cotrimoxazole were 96.4/1.5, 96.2/2.8, 92.4/4.7, and 87.9/7.3%, respectively. The rate of susceptibility and resistance to erythromycin was 2.3/19.9. Multiple resistance to ampicillin, chloramphenicol, tetracycline, and cotrimoxazole was observed in 15 isolates (0.6%), and resistance to three drugs simultaneously in 72 (1.5%). The incidence of beta-lactamase producing strains was similar to that seen in the first European study performed in 1986 (9.1% vs. 10.9%), and was half that observed in US isolates collected in 1986.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial susceptibility of Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae isolates causing meningitis in The Netherlands, 1993-1994

“…A significantly higher prevalence of ampicillin resistance was found among our type b as compared with non-type b strains. This was also seen in the USA, but not in previous studies from Europe and South Africa (Doern et al, 1988;Kayser et al, 1990;Hussey et al, 1994). One study mentioned highest rates of ampicillin resistance among children aged less than 5 years, comparable to our findings (Doern et al, 1988).…”

“…Resistance to chloramphenicol was associated with resistance to ampicillin in 0.9% of strains. These findings are similar to prevalences among isolates from different types of specimen in nine European countries and South Africa (1991-92) (Kayser, Morenzoni & Santanam, 1990;Hussey et al, 1994). In the USA ampicillin resistance in H. influenzae occurred twice as often, yet chloramphenicol resistance was rare (Doern et al, 1988).…”

“…One study mentioned a 7% prevalence of discrepancy between MIC results and the nitrocephin assay among resistant strains (Kayser et al, 1990). A discrepancy is often explained by the fact that /Mactamase producing strains yield inhibition ellipses which may be difficult to interpret (Jorgensen et al, 1991).…”

Susceptibility of Haemophilus Influenzae to Selected Antimicrobial Agents

“…Multiple resistance to three drugs was found in 4% (6/150) of our isolates. This is in accord with a recent European study, 6 where resistance to three or more drugs was observed in 3.4% of isolates. Chloramphenicol resistance in our series was linked to that of ampicillin and tetracycline in four of our isolates.…”

“…However, surveys of antimicrobial susceptibility of this organism indicate that geographical variations are common in both developed [2][3][4][5][6] and developing countries. [7][8][9] It is therefore essential to recognize the incidence of antimicrobial resistance of this organism in a particular geographical area.…”