Age-stratified burden of pneumococcal community acquired pneumonia in hospitalised Canadian adults from 2010 to 2015

BACKGROUND

In Canada, 13-valent pneumococcal conjugate vaccine (PCV13) is recommended in childhood, in individuals at high risk of invasive pneumococcal disease (IPD) and in healthy adults aged ≥65 years for protection against vaccine-type IPD and pneumococcal community-acquired pneumonia (pCAP). Since vaccine recommendations in Canada include both age-based and risk-based guidance, this study aimed to describe the burden of vaccine-preventable pCAP in hospitalised adults by age.

METHODS

Surveillance for community-acquired pneumonia (CAP) in hospitalised adults was performed prospectively from 2010 to 2015. CAP was radiologically confirmed, and pCAP was identified using blood and sputum culture and urine antigen testing. Patient demographics and outcomes were stratified by age (16-49, 50-64, ≥65 and ≥50 years).

RESULTS

Of 6666/8802 CAP cases tested, 830 (12.5%) had pCAP, and 418 (6.3%) were attributed to a PCV13 serotype. Of PCV13 pCAP, 41% and 74% were in adults aged ≥65 and ≥50 years, respectively. Compared with non-pCAP controls, pCAP cases aged ≥50 years were more likely to be admitted to intensive care units (ICUs) and to require mechanical ventilation. Older adults with pCAP were less likely to be admitted to ICU or required mechanical ventilation, given their higher mortality and goals of care. Of pCAP deaths, 67% and 90% were in the ≥65 and ≥50 age cohorts, respectively.

CONCLUSIONS

Adults hospitalised with pCAP in the age cohort of 50-64 years contribute significantly to the burden of illness, suggesting that an age-based recommendation for adults aged ≥50 years should be considered in order to optimise the impact of pneumococcal vaccination programmes in Canada.

Epidemiologic typing of Salmonella enterica serotype enteritidis in a Canada-wide outbreak of gastroenteritis due to contaminated cheese

A major Canada-wide outbreak of gastroenteritis due to Salmonella enterica serotype Enteritidis phage type (PT) 8 occurred in 1998, and this was traced to contaminated cheese in a commercial lunch pack product. Phage typing and pulsed-field gel electrophoresis linked the clinical and cheese isolates of serotype Enteritidis but failed to differentiate outbreak from nonoutbreak PT 8 strains. Further differentiation was made by biotyping based on melibiose fermentation.

Drug resistance, plasmids, biotypes and susceptibility to bacteriophages of Salmonella isolated from poultry in Canada

Salmonella isolates from 295 layer and 294 broiler flocks in Canada were examined to determine resistance to antimicrobial agents, plasmid profiles, biochemical properties, and susceptibility to polyvalent bacteriophages. Except for the high number of strains resistant to spectinomycin (97.8%), the frequency of drug resistance of Salmonella isolates from layer flocks was low. None of 457 isolates from layer flocks was resistant to amikacin or ciprofloxacin, and less than 2% of the strains were resistant to cephalothin, chloramphenicol, cotrimoxazole, gentamicin, kanamycin, neomycin, nitrofurantoin, and/or polymyxin B. About 3% of the strains were resistant to ampicillin, carbenicillin and/or tetracycline, whereas 8% of the strains were resistant to sulfisoxazole. Salmonella anatum var. O15+ and S. typhimurium var. copenhagen strains were resistant to multiple antimicrobial agents. None of 1159 Salmonella strains from broiler flocks was resistant to amikacin, cephalothin, ciprofloxacin or polymyxin B, less than 1% of the strains were resistant to chloramphenicol, 2% were resistant to ampicillin, carbenicillin and/or chloramphenicol; 5-7% were resistant to the aminoglycosides gentamicin, kanamycin and/or neomycin; 6% were resistant to nitrofurantoin; 10% to tetracycline; 14% to sulfisoxazole; and 99% to spectinomycin. A high percentage of S. binza, S. anatum var. O15+, S. schwarzengrund and S. heidelberg strains were resistant to antimicrobial agents. Some of the single or multiple resistances were encoded by conjugative plasmids or by plasmids that were thermosensitive for transfer. Eight percent of S. heidelberg strains did not produce hydrogen sulfide. Ninety-seven percent of the Salmonella strains were susceptible to the lytic effect of polyvalent bacteriophages.

Drug resistance and biochemical characteristics of Salmonella from turkeys

A study was conducted to determine the antibiotic resistance and biochemical characteristics of 2690 Salmonella strains belonging to 52 serovars and isolated from environmental and feed samples from 270 turkey flocks in Canada. Resistance of the Salmonella strains to the aminoglycoside antibiotics varied widely; none of the strains were resistant to amikacin, 14.2% were resistant to neomycin, 25.8% were resistant to gentamicin, and 27.7% of the strains were resistant to kanamycin. Most strains (97.6%) were resistant to the aminocyclitol, spectinomycin. Regarding resistance to the beta-lactam antibiotics, 14.3% and 14.4% of the strains were resistant to ampicillin and carbenicillin, respectively, whereas only 5 (0.2%) of the strains were resistant to cephalothin. None of the strains were resistant to the fluoroquinolone ciprofloxacin or to polymyxin B. Resistance to chloramphenicol and nitrofurantoin was found in 2.4% and 7% of the strains, respectively. Only 1.7% of the strains were resistant to the trimethoprimsulfamethoxazole combination, whereas 58.1% were resistant to sulfisoxazole. Thirty-eight percent of the strains were resistant to tetracycline. Salmonella serovars differed markedly in their drug resistance profiles. Biochemical characterization of the Salmonella showed that the S. anatum, S. saintpaul and S. reading serovars could be divided into distinct biotypes.