To describe the microbiology and outcome of iliopsoas abscess (IPA) in a large case series, we analyzed 124 cases of IPA collected from 1990 through 2004 in 11 hospitals in Spain. Twenty-seven (21.8%) patients had primary and 97 (78.2%) had secondary IPA. The main sources of infection were bone (50.5%), gastrointestinal tract (24.7%), and urinary tract (17.5%). A definitive microbial diagnosis was achieved in 93 (75%) cases. Abscess culture was the most frequent procedure leading to microbial diagnosis, followed by blood cultures. Staphylococcus aureus, Escherichia coli, and Bacteroides species were the most frequent microbial causes: S. aureus was the most common organism in patients with primary abscesses (42.9%) and with abscesses of skeletal origin (35.2%), whereas E. coli was the leading organism in those with abscesses of urinary (61.5%) and gastrointestinal (42.1%) tracts. Mycobacterium tuberculosis was found in 15 patients, 4 of them associated with human immunodeficiency virus (HIV) infection. Twenty (21.5%) cases had polymicrobial infections; these were more common among patients with abscesses of gastrointestinal origin. Information on clinical outcome was available for 120 patients; 19 (15.8%) had a relapse and 6 (5%) died due to complications related to the IPA. Patients who died were older and more likely to have bacteremia and E. coli isolated from cultures. In conclusion, secondary IPA is more prevalent than primary IPA. Among those with secondary IPA, most abscesses are secondary to a skeletal source. A bacterial etiology can be identified in most cases. The overall prognosis of patients with this condition is good.

Goal To analyse the characteristics and mortality-related factors in a series of patients hospitalized for pyogenic liver abscess (PLA). Background Pyogenic liver abscesses are infrequent but potentially life threatening. Factors related to mortality have been less studied. Study The medical records of 84 patients, 56 men and 28 women, mean age of 64.4 years (SD: 14) who were hospitalized between 1992 and 2005 owing to a PLA were reviewed. The past medical history, clinical signs and symptoms, laboratory values, imaging studies, microbiological features, treatment, complications and mortality were recorded. Factors related to complications and mortality were analysed. Results One or more bacteria were isolated in 65 patients (77.4%), being Streptococcus spp. (40.5%), Escherichia coli (27.4%), Klebsiella spp. (14.3%) and anaerobics (17.9%) the most frequent isolates. Complications developed in 60.7% of the cases, the most common one being a right pleural effusion (34.5%). Mortality rate was 19% (95% confidence interval: 10–28%). Mortality was associated with age (P=0.005), a previous history of coronary heart disease (P=0.016), absence of fever (P=0.001), development of sepsis and/or septic shock (P<0.001), raise of bilirubin levels (P=0.004), a biliary (P=0.035), or cryptogenetic origin (P=0.039), infection owing to E. coli (P=0.01) or to Candida (P=0.009) and development of pneumonia (P<0.001). Logistic regression revealed sepsis and/or septic shock as an independent risk factor for mortality. Conclusions Mortality associated with PLA is high. The main risk factor for mortality is the development of sepsis and/or septic shock.