Clinical Features and Prognostic Factors of Anaerobic Infections: A 7-Year Retrospective Study

Abstract

Background/Aims Risk factors for mortality resulting from anaerobic infection are incompletely defined. The clinical significance of a broad range of pathogenic obligate anaerobic organisms was examined, and factors independently associated with mortality were identified in patients with clinically significant anaerobic infections. Methods The medical records of 1,050 patients with anaerobic infections were retrospectively reviewed at Severance Hospital in Seoul, Korea. Results The mean age of the patients was 54.1±16.8 years, and 57.7% were men. Overall, 320 (30.5%) patients with case-defined illness experienced pain at the affected site, and 230 (21.9%) experienced pus flow from lesions. Ten (1.4%) patients presented with shock, and 80.3% of the clinically significant cases were polymicrobial anaerobic infections. The mean number of pathogens, including aerobic and anaerobic bacteria, was 3.7±1.0 (minimum 1, maximum 5), and the number of anaerobic organisms was 1.0±0.3 in each specimen. The major pathogens by rank were the Bacteroides fragilis group, which accounted for 41.8% of anaerobic infections, followed by Clostridium spp. (11.8%), Prevotella spp. (9.4%), and Peptostreptococcus spp. (8.4%). Escherichia coli (17.5%), Staphylococcus aureus (7.5%), and Klebsiella pneumoniae (7.5%) were common concomitant aerobic organisms. The overall crude mortality rate resulting from anaerobic infection was 29.7%. Among the determining factors associated with mortality, liver disease ( p =0.003) and old age ( p =0.005) were significant in multivariate analysis. Conclusions Anaerobic infection is polymicrobial and has a significant role in morbidity and mortality. Underlying liver disease was associated with poor prognosis in anaerobic infection.

Expression of Bacteroides fragilis hemolysins in vivo and role of HlyBA in an intra‐abdominal infection model

“…; Mazuski and Solomkin ; Park et al. ). Despite being only 1% or less of the Bacteroides that colonize the human colon, B. fragilis is by far the most frequent anaerobe isolated from anaerobic infections.…”

“…Following initial bacterial peritoneal contamination, the host defenseslymphatic clearance, phagocytosis, and sequestration by fibrinrapidly clear the bacteria within minutes via lymphatic system and exposed them to systemic defenses (McClean et al 1994;van Till et al 2007;Mazuski and Solomkin 2009). While most of bacteria are cleared by host defenses, Bacteroides fragilis emerges as the most prevalent anaerobic organism in human infections (Finegold and George 1989;McClean et al 1994;Mazuski and Solomkin 2009;Park et al 2009). Despite being only 1% or less of the Bacteroides that colonize the human colon, B. fragilis is by far the most frequent anaerobe isolated from anaerobic infections.…”

“…Despite being only 1% or less of the Bacteroides that colonize the human colon, B. fragilis is by far the most frequent anaerobe isolated from anaerobic infections. It accounts for about 50-70% of all anaerobes isolated from human infections such as intra-abdominal abscesses, peritonitis, infections of the female genital tract, deep wounds, brain abscesses, and bacteremia (Brook 1989;Finegold and George 1989;Brook and Frazier 2000;Mazuski and Solomkin 2009;Park et al 2009). The virulence of B. fragilis is highlighted by its high frequency of recovery from blood cultures compared with other species of the genus.…”

Ferritin-like family proteins in the anaerobe Bacteroides fragilis: when an oxygen storm is coming, take your iron to the shelter

“…While most of the contaminant bacteria will be cleared by the host immune defenses within minutes, B. fragilis , which comprises only 0-5-1 % of the human normal intestinal microflora, emerges as the most frequent anaerobe isolated from intra-abdominal abscesses, peritonitis, infections of the female genital tract, deep wounds, brain abscesses and bacteremia. B. fragilis accounts for about 50–70 % of all anaerobic bacteria isolated from human infections (Brook 1989; Finegold and George 1989; McClean et al 1994; Brook and Frazier 2000; Mazuski and Solomkin 2009; Park et al 2009). The pathogenicity traits of B. fragilis are not completely understood but virulence factors such as capsular polysaccharides, adherence, production of proteases, neuraminidase, iron acquisition and resistance to oxidative stress play an important role (Smith et al 2006; Wexler 2007).…”

Epidemiology and antimicrobial susceptibilities of wound isolates of obligate anaerobes from combat casualties

“…In contrast, patients with isolation of Candida or obligate anaerobic bacteria have no clear injury pattern, exposure, or therapy association, limiting the ability to risk stratify patients for early pathogen directed intervention (Murray et al, 2009a, 2011). Though there is limited data demonstrating that patients with infections due to obligate anaerobes have higher mortality (20–39%), it is unclear if increased mortality is related to the pathogen, severity of injury, or co-infections, which is similar to the findings in combat casualties from whom Candida is isolated (Ani et al, 2015; Blyth et al, 2014; Nguyen et al, 2000; Park et al, 2009; Redondo et al, 1995). …”