Antimicrobial Susceptibility Profile of Streptococcus pseudopneumoniae Isolated from Sputum

Abstract

Streptococcus pseudopneumoniae is a recently described member of the Streptococcus mitis/oralis group of viridans streptococci that shares some characteristics with Streptococcus pneumoniae (1). Key characteristics of S. pseudopneumoniae are the absence of pneumococcal capsule, insolubility in bile, resistance or indeterminate susceptibility to optochin when incubated in 5% CO 2 but susceptibility to optochin when incubated in ambient air, and positive reactions in DNA probe hybridization and antigen detection tests (1, 3). The clinical relevance of S. pseudopneumoniae has not yet been established, although it may be associated with chronic obstructive pulmonary disease (3). As yet, the antibiotic susceptibility profile of S. pseudopneumoniae has not been reported in detail. The aim of this study was to determine the antibiotic susceptibility profile of a large number of S. pseudopneumoniae isolates recovered from clinical specimens. Ninety-five isolates of S. pseudopneumoniae collected between 2000 and 2007 were studied. All isolates had been recovered as the predominant organism from good-quality sputum specimens containing Ͼ25 leukocytes and Յ10 squamous epithelial cells per 100ϫ field. The isolates were identified on the basis of phenotypic characteristics as previously described (1, 3). MICs were determined by broth microdilution with the Micro-Scan Micro STREP plus 1 system (Dade Behring, West Sacramento, CA). The MICs of penicillin, ampicillin, ceftriaxone, cefotaxime, cefepime, meropenem, chloramphenicol, clindamycin, erythromycin, azithromycin, tetracycline, vancomycin, gatifloxacin, levofloxacin, and trimethoprim-sulfamethoxazole were determined. Strains for which the MICs were greater than the highest dilution included on the Micro-Scan panel were retested with the Etest (AB Biodisk, Solna, Sweden) to determine the precise MIC. Susceptibility breakpoints were based on CLSI guidelines (2). Strains showing

Clinical and Antimicrobial Susceptibility Data of 140 Streptococcus pseudopneumoniae Isolates in France

“…Among the latter, COPD, which was previously reported as a condition associated with S. pseudopneumoniae isolation, was rarely observed in this study (15 out of the 120 non-CF patients, including 5 patients with bronchitis and 7 with pneumonia) (4,6). We documented high rates of resistance to erythromycin and tetracycline, as previously reported (6,7). Of note, erythromycinresistant S. pseudopneumoniae isolates mainly exhibited an efflux phenotype, contrasting with the MLS resistance phenotype observed in 87.3% of the S. pneumoniae isolated in our institution during the study period.…”

Streptococcus pseudopneumoniae as an emerging pathogen from patients with respiratory diseases

“…A great resistance rate of the studied S. pseudopneumoniae isolates was recorded for cotrimoxazole (75.0%), penicillin (62.5%) and erythromycin (56.2%) which was consistent with previous studies at which the same resistance pattern has been observed among studied isolates (Keith and Murdoch, 2008;Mohammadi and Dhanashree, 2012). Other studies have also documented a high resistance rate among S. pseudopneumoniae isolates to erythromycin (60%) without any recorded resistance to penicillin (Keith et al, 2006) that was in contrast with our finding and may be due to different antibiotic policy in other countries at which penicillin is used within limits.…”

Streptococcus pseudopneumoniae Identification by Pherotype: a Method To Assist Understanding of a Potentially Emerging or Overlooked Pathogen

“…While multilocus sequence analysis can reveal divergence between species by their housekeeping and virulence gene fragments (11,25), these methods are too cumbersome for large-scale and routine clinical diagnosis. Recent accounts of detection of pseudopneumococcus in carriage and symptomatic hosts with antibiotic resistance necessitate its accurate diagnosis as an emerging causative agent of disease (23). A recent report suggested that sequencing recA could differentiate between S. pneumoniae and S. pseudopneumoniae (43), but the study was performed with a smaller number of pseudopneumococcal strains solely from North America.…”

“…Virulence factors that were once thought to be exclusive to the pneumococcus, such as pneumolysin (encoded by ply) and autolysin A (encoded by lytA), have been detected in commensal streptococcal species (18,35,49), compromising their specificity as species identification markers. The pathogenic potential of S. pseudopneumoniae (the pseudopneumococcus) has been demonstrated in a murine model (12) as well as in humans (2,18,23,24,28,40). Rapid, correct identification of this organism in the clinical setting is essential for diagnosis and for understanding its disease potential.…”