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.

Adequacy of empirical antibiotic treatment is an independent risk factor for mortality in patients with E. coli bacteraemia. MDR E. coli bacteraemia had a worse prognosis due, at least in part, to a lower frequency of correct empirical treatment.

Suppurative mediastinitis developed in 34 (0.9%) of 3,645 patients who underwent median sternotomy at the Hospital Marqués de Valdecilla in Santander, Spain, from 1985 through 1991. These cases were analyzed in a case-control study designed to identify risk factors for poststernotomy mediastinitis. The significant risk factors were (1) preoperative factors: heavy cigarette smoking and history of endocarditis; (2) intraoperative factors: emergency surgery, prolonged duration of surgery, prolonged bypass pump time, ventricular failure, and tearing of the aortic or femoral artery; and (3) postoperative factors: reoperation, prolonged mechanical ventilation, prolonged stay in the intensive-care unit, and tracheostomy. All patients had abnormal sternal wounds (i.e., signs of wound infection or serous discharge). Twelve patients were bacteremic. Thirty-eight organisms were recovered from 31 patients with mediastinitis; 23 of the isolates were gram-positive and 15 were gram-negative. The infections were treated with extensive debridement and appropriate antibiotics. Mortality was 35%. Chronic sternal osteomyelitis was documented in two cases.

Background: previous studies have established that bacterial blood concentration is related with clinical outcome. Time to positivity of blood cultures (TTP) has relationship with bacterial blood concentration and could be related with prognosis. As there is scarce information about the usefulness of TTP, we study the relationship of TTP with clinical parameters in patients with Streptococcus pneumoniae bacteremia.

BackgroundThe objective of this study is to analyze the factors that are associated with the adequacy of empirical antibiotic therapy and its impact in mortality in a large cohort of patients with extended-spectrum β-lactamase (ESBL) - producing Escherichia coli and Klebsiella spp. bacteremia.MethodsCases of ESBL producing Enterobacteriaceae (ESBL-E) bacteremia collected from 2003 through 2008 in 19 hospitals in Spain. Statistical analysis was performed using multivariate logistic regression.ResultsWe analyzed 387 cases ESBL-E bloodstream infections. The main sources of bacteremia were urinary tract (55.3%), biliary tract (12.7%), intra-abdominal (8.8%) and unknown origin (9.6%). Among all the 387 episodes, E. coli was isolated from blood cultures in 343 and in 45.71% the ESBL-E was multidrug resistant. Empirical antibiotic treatment was adequate in 48.8% of the cases and the in hospital mortality was 20.9%. In a multivariate analysis adequacy was a risk factor for death [adjusted OR (95% CI): 0.39 (0.31-0.97); P = 0.04], but not in patients without severe sepsis or shock. The class of antibiotic used empirically was not associated with prognosis in adequately treated patients.ConclusionESBL-E bacteremia has a relatively high mortality that is partly related with a low adequacy of empirical antibiotic treatment. In selected subgroups the relevance of the adequacy of empirical therapy is limited.

Of 41 patients with bone-related infections who were treated for > or =10 days with piperacillin-tazobactam, 14 (34%) developed neutropenia. Cumulative doses of piperacillin administered to neutropenic patients were higher than those administered to nonneutropenic ones (330 vs. 237 g; P=.008), and an inverse correlation was detected between the absolute neutrophil count at the end of treatment and the cumulative dose of piperacillin (r=-0.47, P=.002). Moreover, the incidence of piperacillin-tazobactam-induced neutropenia increased with an increase in the cumulative dose of piperacillin: 0% of patients in the first quartile of cumulative piperacillin doses, 33.3% in the second quartile, 40% in the third quartile, and 66.7% in the fourth quartile.

The time from the start of incubation to a positive reading of blood cultures (time-to-positivity; TTP) is related to the concentration of bacteria in blood. Information concerning the correlation of TTP with clinical parameters, and its usefulness as a prognostic factor in patients with Escherichia coli bacteraemia, is limited. To investigate the relationship of TTP to clinical parameters, 459 cases of monomicrobial E. coli bloodstream infections from a single institution between 1997 and 2005 were reviewed. All cases involved patients who were not undergoing antibiotic treatment at the time of blood sampling. The in-hospital mortality rate was 6.3%. Median TTP was significantly shorter for patients who died than for those who survived (9.7 h, inter-quartile range 7.85-11.05 h vs. 11.2 h, inter-quartile range 10.1-11.4 h; p <0.001). Patients with TTP in the lowest quartile were more likely to be female, to have a non-urinary tract or an unknown origin of bacteraemia, to have severe sepsis or shock, and to subsequently die. In a multivariable Cox regression model, the hazard ratio for death from any cause for patients with a short TTP was 3.13 (95% CI 1.28-7.64; p 0.01). TTP in patients with E. coli bacteraemia provides prognostic information beyond that provided by the presence of haematological illness, a Charlson score > or =3, a non-urinary tract origin of bacteraemia, and the presence of severe sepsis or shock.

The aim of this study was to identify the risk factors for bacteremia in patients with limb cellulitis. Using the administrative and microbiology laboratory databases of a community teaching hospital, a review was conducted of all cases of community-acquired limb cellulitis that occurred during the period 1997-2004 and in which blood cultures had been performed. A comparison of demographical, clinical, and analytical data of patients with bacteremia versus patients without bacteremia was performed by univariate and multivariate analyses. Of 2,678 patients with cellulitis who presented to the hospital's emergency department, 308 were diagnosed with limb cellulitis and had blood cultures. Of these, 57 (18.5%) had bacteremia. In 24 of the 57 (42.1%) patients with bacteremia, the microorganism isolated in blood cultures was non-group-A beta-hemolytic Streptococcus, and in another 14 (24.6%), the microorganism identified was a gram-negative bacterium. Staphylococcus aureus was determined as the cause of bacteremia in just 6 (10.5%) patients and group A Streptococcus in 2 (3.5%). By logistic regression analysis, the following factors were associated with bacteremia: absence of previous antibiotic treatment (OR 5.3, 95% CI 1.4-20.3), presence of two or more comorbid factors simultaneously (OR 4.3, 95% CI 1.6-11.7), length of illness<2 days OR 2.44, 95% CI 1.07-5.56), and proximal limb involvement (OR 6, 95% CI 3.03-12.04). Patients with limb cellulitis who exhibit any of these characteristics are at increased risk of bacteremia. In such patients, it is imperative that blood cultures be performed.