Roser Pericas

Infection caused by Nocardia farcinica: case report and review.

Abstract Nocardia farcinica is a rare Nocardia species causing localised and disseminated infections. A case of Nocardia farcinica infection is presented, and 52 cases previously reported in the literature are reviewed. The hosts usually had predisposing conditions (85%), and acquired the infection through the respiratory tract or skin; the infection then often spread to the brain, kidney, joints, bones and eyes. Pulmonary or pleural infections (43%), brain abscesses (30%) and wound infections (15%) which failed to respond to conventional antimicrobial therapy were the more frequent forms of infection. Nocardia farcinica was frequently isolated from pus (100% of samples), bronchial secretions (41%) and biopsy specimens (63%), but isolation from blood and urine, as in the case presented here, is rare. Antibiotic therapy was adequate in 61% of the patients in whom it was specified, the agents most frequently given being trimethoprim-sulfamethoxazole (54%), amikacin combined with imipenem (7%) and amoxicillin-clavulanate (7%). The high mortality (31%) can be attributed to the severe underlying diseases present, difficulties encountered in identifying the pathogen, inappropriate therapy and late initiation of therapy. Although an infrequent pathogen, Nocardia farcinica should be kept in mind as a cause of infection especially in immunosuppressed patients with indolent infections not responding to third-generation cephalosporins.

Associations between Fc gamma receptor IIA polymorphisms and the risk and prognosis of meningococcal disease

BACKGROUND In vitro studies have shown that the neutrophil Fc gamma receptor IIA (FcgammaRIIA) polymorphism influences the phagocytic capacity of neutrophils and the removal of encapsulated bacteria from the bloodstream. In particular, the R/R131 allotype is associated with less phagocytic activity. SUBJECTS AND METHODS We performed a case-control study to determine the influence of the FcgammaRIIA polymorphism (R/R131, R/H131, H/H131) on the risk and outcome of meningococcal disease. The polymorphisms were measured in 130 patients with microbiologically proven meningococcal disease diagnosed from 1987 to 1998 (cases) and 260 asymptomatic sex-matched blood donors (controls). Clinical manifestations and complications of meningococcal disease were recorded, and a prognostic score (based on age, hemorrhagic diathesis, neurologic signs, and the absence of preadmission antibiotic) therapy was calculated. RESULTS The distributions of FcgammaRIIA allotypes were similar in cases and controls. However, among patients with meningococcal infection, fulminant meningococcal disease (odds ratio [OR] = 3.9; 95% confidence interval [CI]: 1.0 to 16; P = 0.04) and meningococcemia without meningitis (OR = 3.0; 95% CI: 1.4 to 7.8; P = 0.004) were more common in those with the FcgammaRIIA-R/R131 allotype. Complications were also significantly more frequent in these patients. Of the 42 patients with the R/R131 allotype, 31 (74%) had an adverse prognostic score, compared with 7% (4 of 59) of those with the R/H131 allotype and 3% (1 of 29) of those with the H/H131 allotype (P <0.0001). CONCLUSION The FcgammaRIIA-R/R131 allotype is associated with more severe forms of meningococcal disease.

Effect of discontinuing prophylaxis with norfloxacin in patients with hematologic malignancies and severe neutropenia a matched case-control study of the effect on infectious morbidity

The use of fluorinated quinolones for prophylaxis of infections in neutropenic cancer patients has led to a reduction of infections with gram-negative enteric bacilli, but there is concern about the emergence of antibiotic-resistant enterobacterial infections and a rise of gram-positive bacteremias. Due to these concerns, in mid-1995 the use of prophylactic norfloxacin was discontinued in our unit. In order to evaluate the impact of this measure on the infectious morbidity in our unit, 91 severe neutropenic episodes in 58 patients with hematologic malignancies who did not receive norfloxacin prophylaxis (NO group) were closely matched to 91 episodes in 60 patients who received norfloxacin prophylaxis (NORFLO group). There were no differences in the incidence of febrile neutropenia, fever of unknown origin or bacteremia during the first febrile episode. There was a trend for a higher rate of coagulase-negative staphylococcal bacteremia in the NORFLO group (5 vs. 11 cases in the NO and NORFLO groups, respectively, p = NS). Enterobacterial bloodstream infections were more frequent in the NO group (13 vs. 2 cases, respectively, p = 0.01), especially Escherichia coli (9 vs. 1 case, respectively, p = 0.01). Twelve of 13 enterobacterial isolates in the NO group were sensitive to the fluoroquinolones vs. 0/2 in the NORFLO group (p = 0.07). We conclude that the abrupt discontinuation of norfloxacin prophylaxis in our ward led to a rapid increase in the rate of fluoroquinolone-susceptible enterobacterial infections, with a scarce impact on infectious morbidity. This suggests that the selection of resistant flora in an inpatient ward by prophylactic antimicrobials may be reversible following the discontinuation of the prophylactic agent(s).

Bacterial DNA in the diagnosis of spontaneous bacterial peritonitis.

Aliment Pharmacol Ther 2011; 33: 275–284

Relevance of genetically determined host factors to the prognosis of meningococcal disease

To assess the relevance of genetically determined host factors for the prognosis of meningococcal disease, Fc gamma receptor IIA (FcγRIIA), the tumor necrosis factor alpha (TNF-α) gene promoter region, and plasminogen-activator-inhibitor-1 (PAI-1) gene polymorphisms were studied in 145 patients with meningococcal disease and in 290 healthy controls matched by sex. Distribution of FcγRIIA, TNF-α, and PAI-1 alleles was not significantly different between patients and controls. Patients with the FcγRIIA-R/R 131 allotype scored ≥1 point in the Barcelona prognostic system more frequently than patients with other allotypes (odds ratio, 18.6; 95% confidence interval, 7.1–49.0, P<0.0001), and they had a higher risk of sequelae (odds ratio, 3.5; 95% confidence interval, 1.1–11.7; P=0.03). Fc gamma receptor IIA polymorphism was associated with markers of disease severity, but TNF-α and PAI-1 polymorphisms were not.

Early microbiologic diagnosis of spontaneous bacterial peritonitis with BacT/ALERT

BACKGROUND/AIMS Inoculation of ascitic fluid into conventional blood culture bottles is more sensitive than conventional culture in the diagnosis of spontaneous bacterial peritonitis. BacT/ALERT is an automated colorimetric microbial detection system that has been shown to be faster than conventional blood culture bottles in the diagnosis of bacteremia. The aim of the study was to compare the BacT/ALERT system with the conventional culture and the conventional blood culture bottles method in the diagnosis of spontaneous bacterial peritonitis. METHODS All the ascitic fluid samples from patients with cirrhosis hospitalized in our Department between September 1992 and May 1994 (n=1032) were prospectively evaluated. In all cases, an aliquot of ascitic fluid was sent for Grams stain and conventional culture, and 20 ml were inoculated at the bedside into blood culture bottles: 10 ml into conventional blood culture bottles and 10 ml into BacT/ALERT. RESULTS Thirty ascitic fluid infections (23 spontaneous bacterial peritonitis and 7 neutrocytic ascites) and 20 bacterascites were diagnosed. Conventional culture was positive in 10/30 ascitic fluid infections (33.3%), conventional blood culture bottles in 22/30 (73.3%) (p<0.01 compared to conventional culture) and BacT/ALERT in 20/30 (66.6%) (p<0.05 compared to conventional culture, pNS compared to conventional blood culture bottles). The time elapsed for culture positivity was 43.4+/-34.2 h for conventional blood culture bottles and 13.3+/-9.2 h for BacT/ALERT (p<0.001). Thirteen of the 23 cases of spontaneous bacterial peritonitis (56.5%) were detected within the first 12 h with BacT/ALERT, as compared to only three (13%) with conventional blood culture bottles (p<0.03). CONCLUSION The automated system BacT/ALERT provides an earlier microbiologic diagnosis of spontaneous bacterial peritonitis than conventional blood culture bottles with similar sensitivity.

CLINICAL STUDY: BACTERIAL DNA IN DIAGNOSIS OF SPONTANEOUS BACTERIAL PERITONITIS

Aliment Pharmacol Ther 2011; 33: 275–284

Diagnostic accuracy of a 16S ribosomal DNA gene-based molecular technique (RT-PCR, microarray, and sequencing) for bacterial meningitis, early-onset neonatal sepsis, and spontaneous bacterial peritonitis

The diagnostic accuracy of a 16S ribosomal DNA (rDNA) gene-based molecular technique for bacterial meningitis (BM), early-onset neonatal sepsis (EONS), and spontaneous bacterial peritonitis (SBP) is evaluated. The molecular approach gave better results for BM diagnosis: sensitivity (S) was 90.6% compared to 78.1% for the bacterial culture. Percentages of cases correctly diagnosed (CCD) were 91.7% and 80.6%, respectively. For EONS diagnosis, S was 60.0% for the molecular approach and 70.0% for the bacterial culture; and CCD was 95.2% and 96.4%, respectively. For SPB diagnosis, the molecular approach gave notably poorer results than the bacterial cultures. S and CCD were 48.4% and 56.4% for the molecular approach and 80.6% and 89.1% for bacterial cultures. Nevertheless, bacterial DNA was detected in 53.3% of culture-negative samples. Accuracy of the 16S rDNA PCR approach differs depending on the sample, the microorganisms involved, the expected bacterial load, and the presence of bacterial DNA other than that from the pathogen implied in the infectious disease.

Group A Streptococcal Meningitis in the Antibiotic Era

Abstract A case of group A streptococcal meningitis is reported and the 51 cases reported in the literature since 1966 reviewed. A total of 24 men and 24 women were included in the study; the mean age (±SD) was 20.9±25.5 years. Fifty-eight percent of the patients had comorbid conditions, 80% had a distant focus of infection, and 65.8% had blood cultures positive for group A streptococci. Seventy-five per cent of the patients were treated with penicillin. The overall case-fatality rate was 12% (6 patients). Sequelae were more prevalent among children (44%) than among adults (7.7%) (OR=9.43; 95% CI, 1.02–438.95;P=0.03). Group A streptococcus is a rare cause of pyogenic meningitis, affecting mainly children or adults with co-morbidity. Although the case-fatality rate is relatively low, neurological sequelae are frequent among survivors, especially children.

Bacteremia by Gram-Negative Bacilli in Patients with Hematologic Malignancies

To compare the characteristics of bacteremic infections by different aerobic gram-negative bacilli (GNB) in patients with hematologic malignancies, we studied 54 consecutive monomicrobial bacteremias by Enterobacteriaceae (EB), 15 by Pseudomonas aeruginosa, 43 by other non-glucose-fermenting GNB (NGFGNB) and 11 by other GNB. Patients with EB and P. aeruginosa bacteremia usually developed the infection after intensive chemotherapy for leukemia or during a hematopoietic stem cell transplantation, while most infections in outpatients off therapy were due to NGFGNB. A significant proportion of bacteremias by EB (37%) and P. aeruginosa (40%) were accompanied by severe morbidity (septic shock, pneumonia or deep-seated organ infections) vs. only 7% of other NGFGNB (p < 0.01). Most infections by these latter bacteria were catheter-related bacteremias (80 vs. 2% of EB, p < 0.005), while most EB infections (61%) were uncomplicated bacteremias of unknown source (vs. 14% of other NGFGNB, p < 0.005). Appropriate antibiotics alone cured 98% of EB and 73% of P. aeruginosa bacteremias but only 26% of other NGFGNB (p < 0.005 for both differences), which were cured by catheter removal in 70%, usually after failure of antibiotic treatment. In conclusion, our results suggest that there are significant differences in the patient populations and clinical characteristics of bacteremic infections by the classic GNB (EB and P. aeruginosa) and the new NGFGNB in adults with hematologic malignancies.