Health literacy and diabetic retinopathy

Health literacy (HL) is defined as a cognitive and social skill that determines the motivation and ability of individuals to understand and use information to promote and maintain proper health. Inadequate HL has been associated with worse outcomes in diabetes control, poor self-care, and higher hospitalization rates for some chronic diseases. We hypothesized that HL influences the prevalence of diabetic retinopathy (DR) among individuals with type 2 diabetes mellitus (T2DM) and that inadequate glycemic control would mediate this association. This was a cross-sectional study carried out with 288 participants of the "Brazilian Diabetes Study" cohort. Inclusion criteria were people diagnosed with T2DM aged between 40 and 70 years and ability to read and write. In the adequate HL group, DR was found in 16.5% of participants and in the inadequate HL group, it was found in 32.8% (P=0.0081). Individuals with inadequate HL had a higher risk of having DR, and this association was still statistically significant after adjusting for HbA1c, low-density lipoprotein cholesterol, systolic blood pressure, and diastolic blood pressure. In conclusion, HL is related to DR without the mediation of classical clinical variables.

Staphylococcus aureus meningitis in adults: A comparative cohort study of infections caused by meticillin-resistant and meticillin-susceptible strains

BACKGROUND

Staphylococcus aureus meningitis is an uncommon nosocomial infection usually associated with neurosurgical procedures, but spontaneous infections may occasionally appear.

AIMS

To compare the features of meningitis caused by meticillin-resistant (MRSA) and meticillin-susceptible (MSSA) S. aureus and examine the prognostic factors for mortality, including MRSA infection and combined antimicrobial therapy.

METHODS

Retrospective cohort study of 350 adults with S. aureus meningitis admitted to 11 hospitals in Spain (1981-2015). Logistic regression and propensity score matching were used to analyse prognostic factors.

RESULTS

There were 118 patients (34%) with MRSA and 232 (66%) with MSSA. Postoperative infection (91% vs 73%) and nosocomial acquisition (93% vs 74%) were significantly more frequent in MRSA than in MSSA meningitis (P < 0.001). Combined therapy was given to 118 (34%) patients. Overall 30-day mortality rate was 23%. On multivariate analysis, mortality was associated with severe sepsis or shock (odds ratio (OR) 9.9, 95% confidence interval (CI) 4.5-22.0, P < 0.001), spontaneous meningitis (OR 4.2, 95% CI 1.9-9.1, P < 0.001), McCabe-Jackson score rapidly or ultimately fatal (OR 2.8, 95% CI 1.4-5.4, P = 0.002), MRSA infection (OR 2.6, 95% CI 1.3-5.3, P = 0.006), and coma (OR 2.6, 95% CI 1.1-6.1, P < 0.029). In postoperative cases, mortality was related to retention of cerebrospinal devices (OR 7.9, 95% CI 3.1-20.3, P < 0.001).

CONCLUSIONS

Clinical and epidemiological differences between MRSA and MSSA meningitis may be explained by the different pathogenesis of postoperative and spontaneous infection. In addition to the severity of meningitis and underlying diseases, MRSA infection was associated with increased mortality. Combined antimicrobial therapy was not associated with increased survival.

Impact of Staphylococcus aureus phenotype and genotype on the clinical characteristics and outcome of infective endocarditis. A multicentre, longitudinal, prospective, observational study

OBJECTIVE

We aimed to evaluate the impact of Staphylococcus aureus phenotype (vancomycin MIC) and genotype (agr group, clonal complex CC) on the prognosis and clinical characteristics of infective endocarditis (IE).

METHODS

We performed a multicentre, longitudinal, prospective, observational study (June 2013 to March 2016) in 15 Spanish hospitals. Two hundred and thirteen consecutive adults (≥18 years) with a definite diagnosis of S. aureus IE were included. Primary outcome was death during hospital stay. Main secondary end points were persistent bacteraemia, sepsis/septic shock, peripheral embolism and osteoarticular involvement.

RESULTS

Overall in-hospital mortality was 37% (n = 72). Independent risk factors for death were age-adjusted Charlson co-morbidity index (OR 1.20; 95% CI 1.08-1.34), congestive heart failure (OR 3.60; 95% CI 1.72-7.50), symptomatic central nervous system complication (OR 3.17; 95% CI 1.41-7.11) and severe sepsis/septic shock (OR 4.41; 95% CI 2.18-8.96). In the subgroup of methicillin-susceptible S. aureus IE (n = 173), independent risk factors for death were the age-adjusted Charlson co-morbidity index (OR 1.17; 95% CI 1.03-1.31), congestive heart failure (OR 3.39; 95% CI 1.51-7.64), new conduction abnormality (OR 4.42; 95% CI 1.27-15.34), severe sepsis/septic shock (OR 5.76; 95% CI 2.57-12.89) and agr group III (OR 0.27; 0.10-0.75). Vancomycin MIC ≥1.5 mg/L was not independently associated with death during hospital nor was it related to secondary end points. No other genotype variables were independently associated with in-hospital death.

CONCLUSIONS

This is the first prospective study to assess the impact of S. aureus phenotype and genotype. Phenotype and genotype provided no additional predictive value beyond conventional clinical characteristics. No evidence was found to justify therapeutic decisions based on vancomycin MIC for either methicillin-resistant or methicillin-susceptible S. aureus.

Pathogen-related factors affecting outcome of catheter-related bacteremia due to methicillin-susceptible Staphylococcus aureus in a Spanish multicenter study

Even with appropriate clinical management, complicated methicillin-susceptible Staphylococcus aureus (MSSA) catheter-related bacteremia (CRB) is frequent. We investigated the influence of molecular characteristics of MSSA strains on the risk of complicated bacteremia (CB) in MSSA-CRB. A multicenter prospective study was conducted in Spain between 2011 and 2014 on MSSA-CRB. Optimized protocol-guided clinical management was required. CB included endocarditis, septic thrombophlebitis, persistent bacteremia and/or end-organ hematogenous spread. Molecular typing, agr functionality and DNA microarray analysis of virulence factors were performed in all MSSA isolates. Out of 83 MSSA-CRB episodes included, 26 (31.3%) developed CB. MSSA isolates belonged to 16 clonal complexes (CCs), with CC30 (32.5%), CC5 (15.7%) and CC45 (13.3) being the most common. Comparison between MSSA isolates in episodes with or without CB revealed no differences regarding agr type and functionality. However, our results showed that CC15 and the presence of genes like cna, chp and cap8 were associated with the development of CB. The multivariate analysis highlighted that the presence of cna (Hazard ratio 2.9; 95% CI 1.14-7.6) was associated with the development of CB. Our results suggest that particular CCs and specific genes may influence the outcome of MSSA-CRB.

Significance of the isolation of Staphylococcus aureus from a central venous catheter tip in the absence of concomitant bacteremia: a clinical approach

The optimal approach following the isolation of Staphylococcus aureus from an intravascular catheter tip in the absence of concomitant bacteremia remains unclear. We aimed to determine the rate of delayed complications in these patients. We performed a retrospective observational study (during the period 2002-2012) including patients with a catheter tip culture yielding S. aureus. Patients were followed up for ≥6 months. The primary endpoint was the occurrence of delayed staphylococcal complications (either bacteremia and/or metastatic distant infections). A total of 113 patients were included (75 % male, median age 61 years): 46 and 67 with negative and positive blood cultures, respectively. We found a lower rate of delayed staphylococcal complications in cases with no bacteremia within 48 h since catheter removal than in cases of confirmed S. aureus catheter-related bacteremia (0.0 % vs. 25.4 %; p-value < 0.001). In the group without bacteremia, there was a subgroup of 15 patients (32.6 %) who did not receive antimicrobial treatment. Again, delayed complications occurred less commonly in this subgroup of patients without bacteremia (0.0 % vs. 25.4 %; p-value = 0.033). In contrast to patients with S. aureus catheter-related bacteremia, no delayed infectious complications were observed in patients with an isolated catheter tip culture yielding S. aureus and negative blood cultures within 48 h of catheter removal. Futures studies are needed to assess if the therapeutic approach could be different for this group of patients.

Factors associated with severity in invasive community-acquired Staphylococcus aureus infections in children: a prospective European multicentre study

Staphylococcus aureus is the main pathogen responsible for bone and joint infections worldwide and is also capable of causing pneumonia and other invasive severe diseases. Panton-Valentine leukocidin (PVL) and methicillin-resistant S. aureus (MRSA) have been studied as factors related with severity in these infections. The aims of this study were to describe invasive community-acquired S. aureus (CA-SA) infections and to analyse factors related to severity of disease. Paediatric patients (aged 0-16 years) who had a CA-SA invasive infection were prospectively recruited from 13 centres in 7 European countries. Demographic, clinical and microbiological data were collected. Severe infection was defined as invasive infection leading to death or admission to intensive care due to haemodynamic instability or respiratory failure. A total of 152 children (88 boys) were included. The median age was 7.2 years (interquartile range, 1.3-11.9). Twenty-six (17%) of the 152 patients had a severe infection, including 3 deaths (2%). Prevalence of PVL-positive CA-SA infections was 18.6%, and 7.8% of the isolates were MRSA. The multivariate analysis identified pneumonia (adjusted odds ratio (aOR) 13.39 (95% confidence interval (CI) 4.11-43.56); p 0.008), leukopenia at admission (<3000/mm(3)) (aOR 18.3 (95% CI 1.3-259.9); p 0.03) and PVL-positive infections (aOR 4.69 (95% CI 1.39-15.81); p 0.01) as the only factors independently associated with severe outcome. There were no differences in MRSA prevalence between severe and nonsevere cases (aOR 4.30 (95% CI 0.68- 28.95); p 0.13). Our results show that in European children, PVL is associated with more severe infections, regardless of methicillin resistance.

Preterm infant gut colonization in the neonatal ICU and complete restoration 2 years later

Preterm infants in a neonatal intensive care unit (NICU) are exposed to multidrug-resistant bacteria previously adapted to the hospital environment. The aim of the present study was to characterize the bacterial antibiotic-resistant high-risk lineages colonizing preterm infants during their NICU stay and their persistence in faeces after 2 years. A total of 26 preterm neonates were recruited between October 2009 and June 2010 and provided 144 faecal samples. Milk samples (86 mother's milk, 35 human donor milk and 15 formula milk) were collected at the same time as faecal samples. An additional faecal sample was recovered in 16 infants at the age of 2 years. Samples were plated onto different selective media, and one colony per morphology was selected. Isolates were identified by 16S rDNA nucleotide sequence and MALDI-TOF. Antibiotic susceptibility (agar dilution), genetic diversity (RAPD, PFGE and MLST) and virulence factors (only in enterococcal and staphylococcal isolates) were determined by PCR. A high proportion of antibiotic-resistant high-risk clones was detected in both faecal and milk samples during the NICU admittance. Almost all infants were colonized by Enterococcus faecalis ST64 and Enterococcus faecium ST18 clones, while a wider genetic diversity was observed for the Gram-negative isolates. Multidrug-resistant high-risk clones were not recovered from the faecal samples of the 2-year-olds. In conclusion, the gut of preterm infants admitted to the NICU might be initially colonized by antibiotic-resistant and virulent high-risk lineages, which are later replaced by antibiotic-susceptible community ones.

Electronic situation report in a nuclear power plant

During the last years the introduction of an electronic situation report system in nuclear power plants has been intensively discussed in the working group emergency staff coordinators of the VGB (‘Verband der Großkraftwerksbetreiber’). In parallel, many federal state authorities as well as the German Ministry of the Environment already successfully started to operate such a system. Based on a solution developed for the ministry for environment Baden-Württemberg, the specific requirements are adapted and extended for the operation in a nuclear power plant. The most important features are easy handling, open interfaces to the systems of the authorities, and flexibility for functional extensions. The advantages recognized after the first test stages led the nuclear power plants Biblis and Neckarwestheim to the decision to introduce such a system at the plant site. First progress and experience gained are reported from the perspective of the crisis management group of the power plant.

Determination and evaluation of the radiological situation using mobile measurements during the ground phase

The nuclear reactor remote monitoring system of the state of Baden-Württemberg (Kernreaktor-Fernüberwachung Baden-Württemberg – KFÜ BW) is implemented according to the recently renewed “recommendations for remote monitoring of nuclear power plants”. In Baden-Württemberg, the application area of the system covers both, the surveillance of internal procedures on one hand, and the handling of incidents or accidents on the other. The following paper shows the role of the KFÜ regarding the determination and evaluation of the radiological situation in the range of off-site emergency response. Progress is reported on the measurement conception and the technical possibilities for the investigation of the radiological situation after the end of the deposition of radio nuclides (ground phase).

Differential findings regarding molecular epidemiology of tuberculosis between two consecutive periods in the context of steady increase of immigration

The demographic characteristics of the population of Madrid, with a steady increase in immigrants, from 4.7% in 1998 to 17.4% in 2007, provide an opportunity to study in depth the transmission of TB. Our aim was to compare two 3-year longitudinal molecular studies of TB to define transmission patterns and predictors of clustering. Two prospective population-based molecular and epidemiological studies (2002-2004 and 2005-2007) of TB patients were conducted in nine urban districts in Madrid using the same methodology. During the period 2002-2007, 2248 cases of TB were reported, and the incidence decreased from 23.5 per 100,000 in 2002 to 20.8 in 2007 (p <0.001). A total of 1269 isolates were molecularly characterized and included in the study. The comparison between the two periods showed that the percentage of foreign-born patients among TB cases increased from 36.2% to 45.7% (p <0.001). Furthermore, the percentage of clustered cases decreased (36.6% vs. 30.6%; p 0.028), and this decline was associated with a decrease of clustered cases among men and people under 35 years. We also observed a decrease in cases belonging to clusters containing ≥ 6 people (14.2% vs. 8.2%; p <0.001), and in cases belonging to mixed clusters containing Spanish-born and foreign-born patients (18.5% vs. 11.1%, p <0.001). Our molecular epidemiology study provides clues to interpret the decrease in the incidence of TB in a context of steady increase of immigration. In our region, the decrease in the incidence of TB can be explained predominantly as a result of a decline in recent transmission.

Panton-Valentine leukocidin-positive Staphylococcus aureus skin and soft tissue infections among children in an emergency department in Madrid, Spain

Fifty-three children who attended the emergency department with community-associated (CA) Staphylococcus aureus skin and soft tissue infections (SSTIs) were enrolled in the study. Seven cases of infection (13.2%) were due to methicillin-resistant S. aureus (MRSA). Twelve of 46 available isolates (26.1%) were Panton-Valentine leukocidin (PVL)-positive. PVL-positive S. aureus SSTIs were more frequently associated with abscesses and cellulitis (75% vs. 38%, p 0.028), and more commonly required incision and drainage (75% vs. 21%, p 0.001). Most PVL-positive CA-MRSA isolates belonged to a single multilocus sequence type (ST8). In contrast, PVL-positive methicillin-susceptible S. aureus isolates belonged to four different sequence types (ST8, ST30, ST80, ST120).

Transmission permeability of tuberculosis involving immigrants, revealed by a multicentre analysis of clusters

In recent years, the number of cases of tuberculosis (TB) among immigrants in Spain has increased markedly, and led to this analysis of the recent transmission patterns of TB in the immigrant population in Madrid. The countries from which the highest number of immigrant cases have been reported were Ecuador (21%), Romania (16%), Morocco (12%), Peru (11%) and Bolivia (9%). Fifty-one per cent of the cases were from South America. In a multicentre study (2004-2006), IS6110 restriction fragment length polymorphism and spoligotyping were used to genotype the Mycobacterium tuberculosis isolates from 632 immigrant cases from 47 countries. A total of 183 cases (29%) were grouped into 59 clusters, which are markers of potential transmission events. Most of the clusters (81%) included patients living in different healthcare districts, and 54% of the clusters were multinational. When a sample of 478 autochthonous cases was included, 53% of the clusters involving immigrants also included autochthonous cases. This study revealed marked transmission permeability among nationalities and between the immigrant and the autochthonous populations.

Molecular, epidemiological and infectivity characterisation of a Mycobacterium tuberculosis strain prevalent in Madrid

The most prevalent strain of Mycobacterium tuberculosis in Madrid, Spain (strain 5) was recovered from 45 cases between 1997 and 2004 and showed a highly homogeneous genetic composition. This strain was not exclusive to Spain, and its spoligotyping signature (ST20) was found in entries from different countries in the SITVIT1 database. Patients infected with strain 5 were more frequently positive for human immunodeficiency virus and autochthonous, and had been in prison more frequently, but strain 5 did not show increased infectivity in an in-vitro model of infection.

Role of nitric oxide in the local and systemic pathophysiological effects induced by Bothrops asper snake venom in mice

OBJECTIVE

To assess the role of nitric oxide in the most relevant local and systemic manifestations in mice injected with the venom of the snake Bothrops asper. Mice were pretreated with nitric oxide synthase inhibitors, and the modifications of the pathological effects induced by the venom were tested.

RESULTS

Inhibition of NO synthesis did not affect acute local myonecrosis and hemorrhage in muscle tissue upon intramuscular injection of venom. Local footpad edema was reduced in mice pretreated with the NO synthase inhibitor L-NAME, and a reduction in the extent of inflammatory infiltrate in muscle tissue was observed after envenomation in mice pretreated with L-NAME and aminoguanidine. The most pronounced effect of NOS inhibition by L-NAME was an increment in the lethal activity of the venom, when injected by the intraperitoneal route.

CONCLUSION

Nitric oxide does not seem to play a significant role in the local acute pathological alterations (hemorrhage and myonecrosis) induced by B. asper venom in mice, although it contributes to edema and inflammatory infiltrate. Nitric oxide exerts a protective role in the systemic pathophysiological manifestations leading to lethality.

Tuberculosis trends in Madrid, 1994-2003: impact of immigration and HIV infection

SETTING

Tuberculosis (TB) cases reported from nine districts of Madrid, where the percentage of immigrant population varied from 1.9% in 1996 to 12.2% in 2003.

OBJECTIVE

To describe the trends in TB incidence from 1994 to 2003.

DESIGN

Observational study.

RESULTS

Between 1994-1995 and 2002-2003, the TB rate decreased from 48.5 (95% CI 45.8-51.1) to 23.3 per 100000 population (95% CI 21.5-25.1) (P < 0.001). The percentage of TB cases co-infected with HIV decreased from 55.9% in 1994 to 14.3% in 2003 (P < 0.001), whereas TB cases in foreigners increased from 2.6% in 1994 to 33.7% in 2003 (P < 0.001).

CONCLUSION

Although the TB rates showed a marked decrease in the study period, the increasing impact of immigration contributed to slowing down the trend.

Accuracy of blood culture for early diagnosis of mediastinitis in febrile patients after cardiac surgery

Postsurgical mediastinitis (PSM) remains a major cause of morbidity and mortality in patients undergoing cardiac surgery procedures. Although prompt diagnosis is crucial in these patients, neither clinical data nor imaging techniques have shown enough sensitivity or specificity for early diagnosis of PSM. The aim of the present study was to assess the validity of blood cultures as a diagnostic test for the early detection of PSM in patients who become febrile after cardiac surgery procedures. During a 4-year period (1999-2002), patients who developed fever (>37.8 degrees C) in the first 60 days after a cardiac surgery procedure were evaluated. Blood cultures were drawn from these patients. PSM was defined as deep infection involving retrosternal tissue and/or the sternal bone directly observed by the surgeon and confirmed microbiologically. Three criteria for positivity of blood cultures were applied: bacteremia, staphylococcal bacteremia, or Staphylococcus aureus bacteremia. For purposes of the analysis, a positive blood culture in patients with PSM was considered a true-positive test and a negative blood culture a false-negative test. Otherwise, in febrile patients without PSM in the postsurgery period, a positive blood culture was considered a false-positive test and a negative blood culture a true-negative test. Blood cultures were drawn from 266 febrile patients in the postsurgery period. PSM occurred in 38 patients (26 cases due to S. aureus, 8 to Staphylococcus epidermidis, 3 to gram-negative enteric bacteria, and one to Pseudomonas aeruginosa). Within the 60-day postsurgical period, blood culture as a diagnostic test was most accurate in patients with S. aureus bacteremia, providing 68% sensitivity, 98% specificity, a positive predictive value of 87%, and a negative predictive value of 95%. If the analysis was limited to the period during which patients are at maximum risk for PSM (day 7-20), the values in patients with S. aureus bacteremia were as follows: 73% sensitivity, 98% specificity, 90% positive predictive value, and 93% negative predictive value. Blood culture is an accurate test for the early diagnosis of PSM in febrile patients after cardiac surgery, particularly in institutions where S. aureus is prevalent in this context. A negative blood culture practically excludes PSM and, during the period of maximum risk for PSM, the presence of S. aureus bacteremia should compel early surgical management.

Recent transmission of tuberculosis in Madrid: application of capture–recapture analysis to conventional and molecular epidemiology

BACKGROUND

Population-based studies using a combination of molecular techniques and conventional epidemiological methods have been used to study the dynamics of tuberculosis (TB) transmission but the relative utility of each technique has not yet been established.

METHODS

A prospective population-based molecular and epidemiological study of patients diagnosed with TB was conducted in three urban districts of Madrid (Spain) during 1997-1999. Analysis was performed using the capture-recapture method including covariates in which conventional epidemiological data and the information on clustered cases obtained by DNA fingerprinting were regarded as independent and complementary procedures.

RESULTS

The estimate obtained by molecular analysis alone, that 31.6% of TB cases were due to recent transmission, was revised to 44.8% (95% CI: 31.4-58.2) using the capture-recapture method. The estimated completeness of the combined databases for identification of recent transmission was 59.2%. Underestimation of the true prevalence of recent transmission was higher with conventional epidemiology than molecular analysis, particularly for patients <35 years old and those with a history of imprisonment.

CONCLUSIONS

In this study, use of the capture-recapture technique allowed us to combine epidemiological information obtained by conventional and molecular methods to quantify the number of cases of recently transmitted TB in the community and identify specific populations at high risk of disease. This information is clearly important because such groups are a prime target for improved TB control measures. In the long term, this combination of techniques may contribute significantly to control the spread of TB.

Neutrophils do not contribute to local tissue damage, but play a key role in skeletal muscle regeneration, in mice injected withBothrops aspersnake venom

Local tissue damage induced by crotaline snake venoms includes edema, myonecrosis, hemorrhage, and an inflammatory response associated with a prominent cellular infiltrate. The role of neutrophils in the local tissue damage induced by Bothrops asper snake venom and by myotoxin I, a phospholipase A2 isolated from this venom, was investigated. Male Swiss mice were pretreated with either an antimouse granulocyte rat monoclonal immunoglobulin G (IgG) antibody or with isotype-matched control antibody. No significant differences in these local effects were observed between mice pretreated with antigranulocyte antibodies and those receiving control IgG. Moreover, myotoxicity induced by B. asper myotoxin I was similar in neutrophil-depleted and control mice. The role of neutrophils in the process of skeletal muscle regeneration was also assessed. Muscle regeneration was assessed by quantifying the muscle levels of creatine kinase and by morphometric histological analysis of the area comprised by regenerating cells in damaged regions of skeletal muscle. Mice depleted of neutrophils and then injected with B. asper venom showed a more deficient regenerative response than mice pretreated with control IgG. Moreover, a drastic difference in the regenerative response was observed in mice injected with myotoxin I, because animals pretreated with control IgG showed a successful regeneration, whereas those depleted of neutrophils had abundant areas of necrotic tissue that had not been removed 7 days after injection, associated with reduced contents of creatine kinase. It is concluded that (1) neutrophils do not play a significant role in the acute local pathological alterations induced by the venom of B. asper, and (2) neutrophils play a prominent role in the process of skeletal muscle regeneration after injection of B. asper venom and myotoxin I, probably related to the phagocytosis of necrotic material and the recruitment of other inflammatory cells, two events directly associated with a successful muscle regenerative response.

Double dimer peptide constructs are immunogenic and protective against Plasmodium falciparum in the experimental Aotus monkey model

Multiple antigen peptide constructs (MAPs) have been used to obtain defined multimeric peptide molecules useful in the development of possible synthetic malaria vaccines. In this context, a method was developed, named double dimer constructs (DDCs), involving the direct synthesis of a dimeric peptide with a C-terminal cysteine. A tetrameric molecule was then obtained by oxidation of sulfhydryl groups. Dimer synthesis was optimized using a Fmoc/tBu strategy, dimers were purified by HPLC, oxidized with DMSO and characterized by HPLC and MALDI-TOF-MS. The tetramers or DDCs obtained by this method were used as immunogens in the search for a possible malaria vaccine. It was found that they were immunogenic in the experimental Aotus monkey model, and were able to induce protective immunity when challenged experimentally with a highly infective Plasmodium falciparum malaria strain.

Synthesis, isolation and characterization of Plasmodium falciparum antigenic tetrabranched peptide dendrimers obtained by thiazolidine linkages

Different chemical alternatives were evaluated for obtaining immunogenic polypeptidic macromolecules which could then be used as vaccines. These were based on the ligation reaction between an unprotected immunogenic peptide and an unprotected multifunctional core peptide; polyantigens, designated dendrimers because their form resembles that of dendritic cells, were thus obtained. The antigen-core ligation alternatives, studied by indirect synthesis, were the formation of oxime, hydrazone and thiazolidine linkages, making use of the reaction between a weak base (acting as nucleophile) and an alkyl aldehyde. The other alternative was the formation of a thioether linkage between a sulfydryl and an alkyl halide. Finally, a multiple antigen peptide (MAP) was synthesized by direct synthesis. All reactions were monitored by SEC-HPLC and SDS-PAGE. Dendrimer molecular mass obtained was confirmed by MS MALDI-TOF. Dendrimer purification was first carried out by concentrating crude reaction products with CP-5000 centricons and (using SEC-HPLC) pure tetramers were then obtained. A 20-residue 9376 immunogenic sequence, from Plasmodium falciparum apical merozoite antigen protein (AMA-1), was used to study the best alternative for chemical ligation. It was observed that thiazolidine formation proceeded with greater yield and in less time than the others. A tetramer has been simultaneously synthesized via thiazolidine with the SPf-66 antimalarial vaccine 45-residue monomer, proving the technique's versatility. The 9376 peptide disulfide bound polymer and SPf-66 (as well as their tetrameric thiazolidine dendrimers) were inoculated in rabbits to evaluate their antibody response. It was observed that titers for tetrameric thiazolidine dendrimers were not just greater but were also sustained over time. Western blot for pre-immune and immune sera showed that dendrimer sera recognized specific Plasmodium falciparum proteins as well as disulfide-bound polymers.

The influence of HIV infection and imprisonment on dissemination of Mycobacterium tuberculosis in a large Spanish city

SETTING

Culture-positive cases of tuberculosis (TB) from the urban population of southern Madrid and from all the prisons located throughout the city.

OBJECTIVE

To determine the frequency with which common strains of Mycobacterium tuberculosis cause disease among patients from both the urban and prison populations of a large Spanish city.

DESIGN

Restriction fragment length polymorphism analysis was performed on culture-positive cases of TB identified between 1 January 1997 and 31 December 1998. Risk factors that might be associated with the dissemination of common strains of TB among the two populations were also investigated.

RESULTS

Two hundred and twenty-one cases of culture-positive TB were identified, 99 (47.8%) of which were grouped in 23 clusters. Eleven were general clusters that spanned the prison and urban populations involved 69 patients (31.2%). Univariate analysis of risk factors showed that age <35 years, human immunodeficiency virus (HIV) infection, intravenous drug use and current or previous imprisonment were all associated at a statistically significant level with inclusion in general clusters. The final logistic regression model showed an interaction between HIV infection and incarceration.

CONCLUSIONS

Dissemination of common strains of M. tuberculosis between prison inmates and the urban population of Madrid is significant, and involves subjects with a history of imprisonment and HIV infection.

Mutations in the rpoB gene of rifampin-resistant Mycobacterium tuberculosis isolates in Spain and their rapid detection by PCR-enzyme-linked immunosorbent assay

Genetic alterations in the rpoB gene were characterized in 50 rifampin-resistant (Rif(r)) clinical isolates of Mycobacterium tuberculosis complex from Spain. A rapid PCR-enzyme-linked immunosorbent assay (ELISA) technique for the identification of rpoB mutations was evaluated with isolates of the M. tuberculosis complex and clinical specimens from tuberculosis patients that were positive for acid-fast bacilli (AFB). Sequence analysis demonstrated 11 different rpoB mutations among the Rif(r) isolates in the study. The most frequent mutations were those associated with codon 531 (24 of 50; 48%) and codon 526 (11 of 50; 22%). Although the PCR-ELISA does not permit characterization of the specific Rif(r) allele within each strain, 10 of the 11 Rif(r) genotypes were correctly identified by this method. We used the PCR-ELISA to predict the rifampin susceptibility of M. tuberculosis complex organisms from 30 AFB-positive sputum specimens. For 28 samples, of which 9 contained Rif(r) organisms and 19 contained susceptible strains, results were concordant with those based on culture-based drug susceptibility testing and sequencing. Results from the remaining two samples could not be interpreted because of low bacillary load (microscopy score of 1+ for 1 to 9 microorganisms/100 fields). Our results suggest that the PCR-ELISA is an easy technique to implement and could be used as a rapid procedure for detecting rifampin resistance to complement conventional culture-based methods.

Inhibition of local hemorrhage and dermonecrosis induced by Bothrops asper snake venom: effectiveness of early in situ administration of the peptidomimetic metalloproteinase inhibitor batimastat and the chelating agent CaNa2EDTA

The effectiveness of the chelating agent CaNa2EDTA and the peptidomimetic matrix metalloproteinase inhibitor batimastat (BB-94) to inhibit local tissue damage induced by Bothrops asper snake venom was studied in mice. Both compounds totally inhibited proteolytic, hemorrhagic, and dermonecrotic effects, and partially reduced edema-forming activity, when incubated with venom prior to injection. Much lower concentrations of batimastat than of CaNa2EDTA were required to inhibit these effects. In addition, batimastat, but not CaNa2EDTA, partially reduced myotoxic activity of the venom. When the inhibitors were administered at various time intervals after envenomation at the same site of venom injection, both compounds were effective in neutralizing local hemorrhage and dermonecrosis if administered rapidly after venom. Inhibition was not as effective as the time lapse between venom and inhibitor injections increased. Owing to the relevance of metalloproteinases in the pathogenesis of local tissue damage induced by B. asper and other pit viper venoms, it is suggested that administration of peptidomimetic metalloproteinase inhibitors or CaNa2EDTA at the site of venom injection may represent a useful alternative to complement antivenoms in the neutralization of venom-induced local tissue damage.

rpoB mutations as an epidemiologic marker in rifampin-resistant Mycobacterium tuberculosis

SETTING

Cases of rifampin-resistant Mycobacterium tuberculosis from the prison population in Madrid and from the general population in Spain.

OBJECTIVE

To identify the rpoB mutations associated with resistance to rifampin and to investigate rpoB genotyping as an epidemiological marker in rifampin-resistant M. tuberculosis.

DESIGN

Twenty-nine rifampin-resistant clinical isolates of M. tuberculosis, 15 obtained from the prison population in Madrid and 14 from the general population in Spain, were characterized by sequence analysis of the 81-bp core region of the rpoB gene and IS6110 DNA fingerprinting.

RESULTS

All the isolates had mutations in rpoB, with those in codon 531 accounting for 41% of the total. Twenty-three (79%) isolates were highly resistant to rifampin (minimum inhibitory concentration > or = 64 mg/L). Nineteen different IS6110 fingerprints were observed: one was shared by seven isolates, one by three, two by two, and 15 were unique. Two IS6110 clusters could be divided into subclusters on the basis of rpoB analysis. Epidemiologic links were identified among patients whose isolates had identical IS6110 patterns and rpoB genotypes, but not between those with identical IS6110 patterns and different rpoB genotypes.

CONCLUSION

Characterization of rpoB mutations can provide information about susceptibility to rifampin and be a useful epidemiological tool for discrimination of rifampin-resistant strains of M. tuberculosis with identical IS6110 fingerprints.

Evidence of exogenous reinfection and mixed infection with more than one strain of Mycobacterium tuberculosis among Spanish HIV-infected inmates

BACKGROUND

As prisons have a high prevalence of tuberculosis and HIV infection, we studied the possibility of multiple tuberculosis infections in a selected population of HIV-infected inmates.

METHODS

Two groups of patients with special characteristics were selected from 226 HIV-infected inmates diagnosed with tuberculosis in the prisons of Madrid (Spain) between 1993 and 1994. The first group contained nine patients who remained culture positive 4 months after the initiation of therapy and the second group contained 28 patients with Mycobacterium tuberculosis isolated from different anatomical sites. DNA typing with IS6110 was performed on all isolates from these patients. In some patients a secondary DNA typing with the plasmid pTBN12 was performed.

RESULTS

Two patients from group A had a second M. tuberculosis strain obtained 4 and 18 months after the initial isolate, with different IS6110 and pTBN12 patterns. In one patient the second strain was multidrug resistant and in the other patient both strains had the same drug-susceptible pattern. The clinical and microbiologic evidence in both patients was consistent with the presence of active tuberculosis caused by a new strain of M. tuberculosis. In group B, the isolates from 27 patients shared similar fingerprint pattern; however, in one patient isolates from sputum and urine showed different IS6110 and pTBN12 patterns, although both strains showed the same drug-susceptible phenotype.

CONCLUSION

This study provides evidence that HIV-infected inmates living under conditions of high environmental infectivity can be infected with two different strains of M. tuberculosis. This finding has implications for the tuberculosis-control programs in prison.

Pharmacological modulation of edema induced by Lys-49 and Asp-49 myotoxic phospholipases A2 isolated from the venom of the snake Bothrops asper (terciopelo)

The pharmacological modulation of edema-forming activity of Bothrops asper myotoxins II and III, Lys-49 and Asp-49 phospholipases A2, respectively, was studied plethysmographically in the mouse foot pad model. Myotoxin III had phospholipase A2 activity, whereas myotoxin II was devoid of enzymatic activity when tested on egg yolk phosphatidylcholine. Both toxins induced a dose-dependent edema of rapid onset. Chemical modification of myotoxin III with p-bromophenacyl bromide abrogated enzymatic activity and significantly reduced edemat-forming activity, although a residual effect remained. Pre-treatment of animals with diphenhydramine, dexamethasone, indomethacin and prazosin significantly reduced the effect of both myotoxins. It is concluded that (a) these myotoxins are important edema-forming components of B. asper venom, (b) enzymatic activity is not a strict requirement to exert this effect, although in the case of myotoxin III it contributes to its development, and (c) several inflammatory mediators participate in mouse foot pad edema induced by these myotoxins.

Neutralization of local tissue damage induced by Bothrops asper (terciopelo) snake venom

Local tissue damage represents a serious consequence of Bothrops asper envenomations. It encompasses a complex series of alterations, including myonecrosis, dermonecrosis, hemorrhage and edema. Due to its rapid development it is difficult to neutralize by antivenoms, especially if there is a delay in serotherapy. Experimental studies with this venom and the polyvalent (Crotalinae) antivenom produced in Costa Rica indicate that antivenom is effective in neutralizing these toxic activities when incubated with the venom prior to injection. However, if venom and antivenom are injected independently in mice, neutralization of these effects is only partial. Moreover, neutralization is not complete even if homologous or heterologous antibodies are present in the circulation before venom is injected. Despite differences in their pharmacokinetic profiles, equine whole IgG and F(ab')2 antivenoms show similar efficacy in the neutralization of edema, hemorrhage and myonecrosis induced by B. asper venom, suggesting that the use of antivenoms made of antibody fragments may not improve neutralization of these effects. This is due, at least in part, to the fact that microvessel disruption by venom components favors a similar antibody concentration in the affected tissues. Recent advances in the development of neutralizing substances of rapid diffusion, that could be injected locally in the field, may contribute to the neutralization of metalloproteinases and phospholipases A2. In addition, the rapid administration of antivenoms with high antibody titers against locally-acting toxins is very important in the treatment of these effects.

Diversity of DNA fingerprints of Mycobacterium tuberculosis isolates in the United States

To investigate the diversity of IS6110 fingerprints of Mycobacterium tuberculosis isolates in the United States and to determine if matching IS6110 fingerprints represent recent interstate tuberculosis transmission, we performed restriction fragment length polymorphism analysis of M. tuberculosis isolates from 1,326 patients in three geographically separated states. Seven hundred ninety-five different IS6110 fingerprint patterns were generated, and pattern diversity was similar in each state. Ninety-six percent of the fingerprint patterns were observed in only one state, demonstrating that most IS6110 fingerprint patterns are confined to a single geographic location. Of the IS6110 fingerprint patterns that were shared by isolates from more than one state, most isolates with 1 to 5 IS6110 copies were separable by pTBN12 fingerprinting whereas those with > 15 copies were not. One high-copy-number M. tuberculosis strain had identical IS6110 and pTBN12 fingerprints and included 57 isolates from three states. Epidemiological data demonstrated significant recent transmission of tuberculosis within each city but not among the states. This suggests that identical fingerprints of isolates from geographically separate locations most likely reflect interstate tuberculosis transmission in the past, with subsequent intrastate spread of disease. Further evaluation of M. tuberculosis strains that cause outbreaks in different geographic locations will provide insight into the epidemiological and bacteriological factors that facilitate the spread of tuberculosis.

Inhibition by CaNa2EDTA of local tissue damage induced by Bothrops asper (terciopelo) venom: application in horse immunization for antivenom production

The ability of the chelating agent CaNa2EDTA to inhibit local tissue damage induced by Bothrops asper venom was studied in mice and in horses used for polyvalent (Crotalinae) antivenom production. CaNa2EDTA was devoid of toxicity when injected i.m. or s.c. inducing only a mild edema. Preincubation of B. asper venom with CaNa2EDTA inhibited hemorrhagic and dermonecrotic activities, but did not reduce edema-forming and myotoxic effects. A group of horses initially immunized with native venoms developed less severe local tissue reactions when injected with booster doses of venom and CaNa2EDTA than when receiving booster injections of venom alone, although they showed a similar antivenom response. Moreover, antivenoms produced from plasmas of horses that received booster injections of either venom alone or venom plus CaNa2EDTA had similar neutralizing activity against lethal, hemorrhagic and coagulant effects induced by B. asper venom. The similar antibody response was corroborated by Western blotting using crude venom and by an ELISA that estimates anti-myotoxin titer. It is concluded that the chelating agent CaNa2EDTA reduces the extent of local tissue damage induced by B. asper venom, without affecting the immune response of horses against pharmacologically-relevant venom components.

Clinical significance of splenic tuberculosis in patients infected with human immunodeficiency virus

To assess the clinical significance of splenic tuberculosis in patients infected with human immunodeficiency virus (HIV) type 1, we compared 20 patients who had splenic tuberculosis with 20 randomly selected, HIV-infected patients with culture-proven tuberculosis for whom splenic involvement had been ruled out by ultrasonography. All of the patients were male prison inmates and intravenous drug users. Statistically significant differences (P < .05) were detected between patients with splenic involvement (median CD4+ cell count, 54/mm3) and those without splenic involvement (median CD4+ cell count, 92/mm3). No specific symptoms suggesting splenic involvement were detected in the patients with splenic tuberculosis. All patients received antituberculous drugs, and none of these patients required splenectomy. The median survival was similar in both groups. Splenic tuberculosis occurs in more-severely immunocompromised HIV-infected patients, the prognosis is generally good, the clinical response to therapy is usually favorable, and splenectomy is rarely necessary.