Two weeks of postsurgical therapy may be enough for high-risk cases of endocarditis caused by Streptococcus viridans or Streptococcus bovis

The duration of antimicrobial therapy after surgery for infective endocarditis (IE) is controversial. A short course of postsurgical therapy is currently accepted only for patients with negative valve culture. We performed a retrospective (1994–2008) analysis of patients who underwent surgery for IE in our hospital and had a high risk of complications (one of more of the following: <2 weeks of antibiotic treatment before surgery; embolism; perivalvular extension; and positive valve culture) to compare outcomes of patients who received short-course antimicrobial therapy (SAT) (median 15 days) or long-course antimicrobial therapy (LAT) (median 32 days), irrespective of the results of valve culture. Our endpoints included length of hospital stay, renal and hepatic failure, relapse, re-infection, and mortality rates 1 year after surgery. During the study period, 140 patients underwent surgery for IE (valve replacement, 87.9%). Of these, 133 fulfilled the high-risk group criteria and 92 completed the antimicrobial schedule. Comparison of patients receiving SAT (37) and LAT (55) showed that the SAT group had a shorter length of hospital stay (29 vs. 40 days, p 0.01), and a trend towards lower frequency of renal failure (5.4% vs. 18.2%, p 0.11) and hepatic failure (5.4% vs. 9.1%, p 0.69), whereas mortality (5.4% vs. 3.6%, p 1), relapse (0% vs. 1.8%, p 1) and re-infection (5.4% vs. 3.6%, p 1) rates were similar between both groups. Multivariate analysis showed that IE caused by Streptococcus viridans or Streptococcus bovis was independently associated with SAT. Postsurgical SAT is safe, especially when IE is caused by Streptococcus viridans or Streptococcus bovis, even in patients at high risk of complications.     

A state of the art review on optimal practices to prevent,recognize, and manage complications associated with intravascular devices in the critically ill

Intravascular catheters are inserted into almost all critically ill patients. This review provides up-to-date insight into available knowledge on epidemiology and diagnosis of complications of central vein and arterial catheters in ICU. It discusses the optimal therapy of catheter-related infections and thrombosis. Prevention of complications is a multidisciplinary task that combines both improvement of the process of care and introduction of new technologies. We emphasize the main component of the prevention strategies that should be used in critical care and propose areas of future investigation in this field.     

In Silico identification of M. TB proteins with diagnostic potential

The development of a new tuberculosis (TB) vaccine has become one of the main objectives of the scientific community. Protein antigens have been widely explored as subunit TB vaccines, however lipid antigens could be equally important to be used or included in such a vaccine. The aim of this study was to demonstrate the potential of a liposome formulation composed of an extract of lipids from Mycobacterium smegmatis (Ms) as a TB vaccine candidate. We evaluated the immunogenicity of this formulation as well as the cross reactive response against antigens from Mycobacterium tuberculosis (MTb) in BALB/c mice. We determined the anti-liposome IgG response in sera from TB patients and from healthy subjects who displayed a positive (PPD+) or negative (PPD-) tuberculin skin test. A significant increase in anti-liposome IgG (p<0.05) was detected in animals immunized with Bacille Calmette-Guérin (BCG) compared with all groups, and in the group immunized with liposomes from Ms (LMs) compared to animals immunized with either LMs adjuvanted with aluminium (LMs-A) or the negative control group (phosphate buffered saline, PBS) respectively. With respect to the cross reactive response against a cocktail of cell wall antigens (CWA) from MTb, significantly higher IgG levels were observed in animals immunized with BCG and LMs compared to negative controls and either, aluminium-adjuvanted liposomes (LMs-A) or montanide (LMs-M) (p<0.05). Furthermore, the anti-liposome IgG response was significantly superior in sera from pulmonary TB patients compared to PPD+ and PPD- healthy subjects (p<0.001) suggesting the expression of these antigens in vivo during active MTb infection. The results obtained provide some evidence for the potential use of liposomes containing total lipid extracts of Ms as a TB vaccine candidate.

     

Extra-abdominal infections due to Gemella species.

OBJECTIVES: To understand the role of Gemella species as a pathogen causing extra-abdominal infections in the Hospital General Universitario Gregorio Mara?ón. MATERIALS AND METHODS: Between 1994 and 1998, one or more isolates of Gemella sp. were found in 128 patients. The 113 patients with isolates from nonsignificant specimens or representing intra-abdominal infections were excluded. The clinical records of the remaining 15 patients were reviewed as well as the more recent literature. RESULTS: Mean age of patients was 41 years. The underlying conditions most frequently noted were intravenous drug users (n=6; 3 positive for human immunodeficiency virus), alcoholism (n=2), cardiovascular disease (n=2), chronic lung disease (n=2), diabetes (n=1), kidney transplant (n=1). The extra-abdominal infections were skin and soft tissue abscess (n=5), empyema (n=4), brain abscess (n=2), primary bacteremia (n=1), lung abscess (n=1), septic thrombophlebitis (n=1), complicated urinary tract infection (n=1). The infection was monomicrobial in six and polymicrobial in nine cases. Surgical drainage and betalactam antibiotics were used. The outcome was favorable in almost all cases. CONCLUSIONS: Gemella sp. should be included as a cause of localized soft-tissue abscesses, empyema, and bloodstream infection. No case of infective endocarditis was found. Although it is susceptible to several antibiotics, Gemella sp. requires a careful microbiologic diagnosis and a subtle clinical interpretation.     

Tuberculosis recurrences: reinfection plays a role in a population whose clinical/epidemiological characteristics do not favor reinfection

BACKGROUND: Tuberculosis (TB) recurrences can be due to either reactivation by the same strain (standard assumption) or reinfection by a new strain. Reinfection has mainly been studied in selected populations with a high risk of reexposure to TB. Our aim was to analyze the role of reinfection in TB recurrences in unselected populations, without the clinical/epidemiological circumstances that favor the involvement of a new different strain of Mycobacterium tuberculosis in the recurrence. METHODS: A molecular typing analysis was performed with 92 sequential isolates of M tuberculosis from 43 patients with recurrent TB, during a 12-year period. The subjects were both positive and negative for the human immunodeficiency virus, most did not adhere to anti-TB therapy, and they lived in an area with a moderate incidence of TB. Recurrence was considered as being caused by reinfection when the molecular fingerprints for the strains involved in the sequential episodes of TB were different. RESULTS: In 14 (33%) of the 43 patients, different M tuberculosis strains were involved in the first and in subsequent episodes of TB. Reinfection was found for patients who were both positive and negative for the human immunodeficiency virus, and most patients did not adhere to anti-TB therapy. Differences between the reinfection and reactivation groups were not significant (P =.77) according to the time interval between episodes. CONCLUSIONS: Reinfection plays an important role in recurrent TB in a population without the clinical/epidemiological circumstances that are usually assumed to favor it. Reinfection should, thus, be considered as a cause of TB recurrences in a wider context than before.     

Klebsiella bacteremia: an analysis of 100 episodes

During a five-year period, 204 patients had klebsiella bacteremia at this institution; these cases constituted 6.6% of the total episodes of bacteremia. The incidence was 2.3 cases per 1,000 admitted patients. A random group of 100 cases was chosen for analysis in the present study. The disease was community acquired in 23%, nosocomially acquired in 77%, unimicrobial in 88%, or part of a polymicrobial bacteremia in 12% of episodes. Three-quarters of the episodes were caused by Klebsiella pneumoniae and the remaining one-quarter, by Klebsiella oxytoca. Portals of entry, in decreasing order of frequency, were urinary, respiratory, and biliary tracts. Twenty-four percent of the Klebsiella isolates were resistant to gentamicin. The most frequent clinical finding (in 96% of the cases) was fever. Shock occurred in 22% and pyogenic metastatic foci, in 5% of the patients. None of the patients had evidence of disseminated intravascular coagulation. Overall mortality was 25%, and factors associated with poor prognosis were inadequacy of antimicrobial chemotherapy, septic shock, type of underlying disease, and clinical condition of the patients.