Antimicrobial Susceptibility of Invasive and Lower Respiratory Tract Isolates of Streptococcus pneumoniae, 1998 to 2007

Abstract

Previous surveys of antimicrobial resistance inStreptococcus pneumoniaehave found differences depending on source of isolate (eg, higher resistance in lower respiratory tract [LRT] versus invasive isolate) and age (higher resistance in children versus adults). Susceptibility profiles in the Calgary Health Region (approximately 1.25 million population) over a 10-year period were studied. Prospective laboratory-based population surveillance forS pneumoniaedisease has been conducted since 1998. Patient demographics and susceptibility testing were analyzed. In total, 2382 patient isolates were available for analysis from 1998 to 2007. Of these, 1170 isolates were invasive while 496 were LRT. Patient age distribution was: younger than five years, 14%; five to 17 years, 6%; 18 to 64 years, 56%; and 65 years or older, 24%. Mean patient age was 44.8 years and 60.0% were male. The overall incidence of nonsusceptibility was: penicillin, 8.2%; amoxicillin, 0.3%; cefuroxime, 6.2%; ceftriaxone, 1.7%; erythromycin, 8.8%; trimethoprim-sulfamethoxazole (TMP-SMX), 25.6%; clindamycin, 2.3%; and levofloxacin, 0.2%. Overall resistance rates were stable, except for increasing erythromycin resistance from 5.4% (1998) to a high of 14.2% (2004) (P=0.007). Isolates that were nonsusceptible to penicillin or TMP-SMX were more likely to be multidrug resistant (P<0.001) compared with penicillin- or TMP-SMX-susceptible isolates. Compared with invasive isolates, LRT isolates showed more resistance to penicillin, TMP-SMX, cefuroxime and erythromycin, and were more likely to be multidrug resistant. Isolates from children younger than five years of age are more likely to be multidrug resistant and resistant to erythromycin and cefotaxime. Ongoing surveillance ofS pneumoniaeisolates is important because resistance rates vary by source and patient age among health care regions.

<p>Serotypes and Antimicrobial Susceptibility of Nasopharyngeal Isolates of <em>Streptococcus pneumoniae</em> from Children Less Than 5 Years Old in Egypt</p>

“…This is in accordance with a previous report that respiratory tract isolates showed more resistance to penicillin, TMP-SMX, cefuroxime and erythromycin, than invasive isolates, and were more likely to be multidrug resistant. 28 The Canadian Bacterial Surveillance Network also reported higher rates of penicillin NS for non-sterile compared with sterile isolates (16.6% versus 12.4%, P=0.005), with respiratory tract specimens constituting 60% of the non-sterile isolates. 29 Similarly, in Quebec, noninvasive isolates demonstrated higher rates of resistance to macrolides, penicillin and cephalosporins.…”

Prevalence of Ceftriaxon-Sensitive Pneumococci Infection and Use of E- Test for Patients Admitted to Ghaem and Imam Reza Hospitals During a Two-Year Period

“…There are some studies in which the trends of Ceftriaxone susceptibility have been evaluated. In a ten-year study (1998 -2007) con-ducted in Calgary, Canada, 1.7% of 1170 pneumococcal isolates were resistant to Ceftriaxone (22). Despite low level of resistance in previous study, in a retrospective study in a university hospital in Taiwan (2000 -2007), 18.4% of non-meningeal and 34.9% of meningeal isolates (a total number of 3729 isolates) were not susceptible to Ceftriaxone (23).…”

Management of acute otitis media in children six months of age and older

“…While there are less available data regarding the antimicrobial susceptibility of bacteria causing AOM, the penicillin susceptibility rate of S pneumoniae, which causes invasive disease, is >90% in most jurisdictions in Canada. (37)(38)(39) Because S pneumoniae is the predominant pathogen in AOM and because it also covers GAS, empirical amoxicillin remains the drug of first choice. M catarrhalis and some strains of H influenzae are more likely to be amoxicillinresistant (ie, are more likely to produce beta-lactamases) but they are less common pathogens, and AOM caused by either bacteria is more likely to resolve spontaneously.…”