Prospective national survey of viridans streptococcal bacteraemia risk factors, antibacterial susceptibility and outcome of 120 episodes

Abstract

The aim of this study was to prospectively investigate 120 cases of viridans streptococcal bacteraemia (VSB) in 117 patients in major university hospitals in Slovakia in 2000–2002 (3 y) for antibacterial susceptibility, risk factors and outcome. From 127 episodes, 16 (13%) of VSB were caused by PEN-R strains and 13 (10%) by ERY-R strains. 32 cases had cancer as underlying disease (20 haematological), 41 had endocarditis and 35 were elderly (>65 y of age) patients. Concerning mortality, 29 of 127 patients died (24%). There were several risk factors associated with mortality. Solid tumour as underlying disease (p<0.02), stroke (p<0.002), concomitant lung infection (p<0.01), endoscopic procedure (p<0.036), intubation (p<0.0008), ventilatory support (p<0.002), and coma (p<0.009) were associated with more deaths. A comparison of 115 bacteraemias to 13 bacteraemias caused by erythromycin-resistant strains of Streptococcus viridans was performed. There were no significant differences in underlying disease, risk factors and mortality. Erythromycin resistance in bacteraemias caused by S. viridans did not have significant impact on outcome of the patients, nor did it show specific relation to analysed risk factors in our study. 14.5% of VSB were cause by PEN-resistant viridans streptococci. Risk factors for penicillin resistance were ventilatory support (p<0.01), intubation (p<0.001) and resistance to other antibiotics: 8 of 16 (50%) of PEN-R VSB were resistant also to erythromycin or cotrimoxazole or tetracycline compared with 9% of PEN-R VSB (p<0.005). Endoscopic procedures in the upper respiratory system were at risk for development of PEN-R VSB. There was also difference in outcome; 71% vs 22.5% (p<0.0002) of cases infected with PEN-R VSB died compared to PEN-S VSB. PEN-R is therefore clinically significant in VSB.