Feasibility and outcomes of transjugular intrahepatic portosystemic shunts in infants

BACKGROUND

Experience with transjugular intrahepatic portosystemic shunts (TIPS) in the pediatric population, especially in infants, is limited.

OBJECTIVE

To evaluate the feasibility, efficacy and safety of TIPS placement in infants.

MATERIALS AND METHODS

This retrospective non-comparative observational cohort study analyzed all pediatric patients  < 12 months of age treated with TIPS while waiting for liver transplant between October 2018 and April 2021. The sample consisted of 10 infants with chronic liver disease. All had refractory ascites and decreased portal vein size. Their mean age ± standard deviation was 5 ± 1 months and their mean weight was 5.4 ± 1.0 kg. We calculated the pediatric end-stage liver disease score and portosystemic gradients before and after TIPS placement. We used ultrasound to check for complications and to assess the presence of ascites. We used paired-sample t-test for the mean comparison of paired variables.

RESULTS

Ten TIPS procedures were performed that were technically and hemodynamically successful except for one, in which an extrahepatic portal puncture required surgical repair. Ascites resolved in three infants and was reduced in six. The portal vein size remained stable after TIPS placement. Four infants had early stent thrombosis and two had late stent thrombosis treated with angioplasty or covered stents.

CONCLUSION

TIPS placement in infants is a feasible, safe and effective procedure.

PI3K, p38 and JAK/STAT signalling in bronchial tissue from patients with asthma following allergen challenge

Background

Inhaled allergen challenges are often used to evaluate novel asthma treatments in early phase clinical trials. Current novel therapeutic targets in asthma include phosphoinositide 3-kinases (PI3K) delta and gamma, p38 mitogen-activated protein kinase (p38) and Janus kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signalling pathways. The activation of these pathways following allergen exposure in atopic asthma patients it is not known.

Methods

We collected bronchial biopsies from 11 atopic asthma patients at baseline and after allergen challenge to investigate biomarkers of PI3K, p38 MAPK and JAK/STAT activation by immunohistochemistry. Cell counts and levels of eosinophil cationic protein and interleukin-5 were also assessed in sputum and bronchoalvelar lavage.

Results

Biopsies collected post-allergen had an increased percentage of epithelial cells expressing phospho-p38 (17.5 vs 25.6%, p = 0.04), and increased numbers of sub-epithelial cells expressing phospho-STAT5 (122.2 vs 540.6 cells/mm², p = 0.01) and the PI3K marker phospho-ribosomal protein S6 (180.7 vs 777.3 cells/mm^2,p = 0.005). Type 2 inflammation was increased in the airways post allergen, with elevated levels of eosinophils, interleukin-5 and eosinophil cationic protein.

Conclusions

Future clinical trials of novel kinase inhibitors could use the allergen challenge model in proof of concept studies, while employing these biomarkers to investigate pharmacological inhibition in the lungs.

Influence of antrum size on gastric emptying and weight-loss outcomes after laparoscopic sleeve gastrectomy (preliminary analysis of a randomized trial)

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) has increased in popularity in recent years as a definitive bariatric procedure. Despite its growing popularity worldwide, the surgical technique is not well standardized. There is a lack of evidence on the matter of the antrum size and its relation to gastric emptying and weight-loss outcomes. The aim of the study is to evaluate the influence of antrum size over gastric emptying and weight-loss outcomes.

METHODS

Twenty-five patients were prospectively randomized according to the distance between the first firing and the pylorus: AR group (antrum resection-2 cm from the pylorus) and AP group (antrum preservation-5 cm from the pylorus). Gastric emptying (%GE) was evaluated by a gastric emptying scintigraphy before surgery, 2 months and 1 year after LSG. Antrum volume was measured using a MultiSlice CT Scan performed 2 months and 1 year after surgery. The percent of excess weight loss (%EWL) was calculated after 1 year follow-up.

RESULTS

At 2 months after LSG the mean %GE was 69.7 ± 18 in the AR group and 72.8 ± 20 in the AP group (p = 0.69). At 1 year it was 66.5 ± 21 and 74.2 ± 16 in the AR and AP groups, respectively (p = 0.30). A significant accelerated gastric emptying was observed at 2 months (p = 0.025) and at 1 year (p = 0.013) in the AP group. Meanwhile in the AR group this increase was not significant (p = 0.12 at 2 months and p = 0.21 at 1 year). Differences regarding the %EWL between groups were no statistically significant (p = 0.74).

CONCLUSIONS

After LSG there is a global tendency to an accelerated gastric emptying, although only significant in the antrum preservation group; however, no differences were observed regarding the %EWL between groups after 1 year follow-up.

Computing quantitative indicators of structural renal damage in pediatric DMSA scans

OBJECTIVES

The proposal and implementation of a computational framework for the quantification of structural renal damage from ^99mTc-dimercaptosuccinic acid (DMSA) scans. The aim of this work is to propose, implement, and validate a computational framework for the quantification of structural renal damage from DMSA scans and in an observer-independent manner.

MATERIALS AND METHODS

From a set of 16 pediatric DMSA-positive scans and 16 matched controls and using both expert-guided and automatic approaches, a set of image-derived quantitative indicators was computed based on the relative size, intensity and histogram distribution of the lesion. A correlation analysis was conducted in order to investigate the association of these indicators with other clinical data of interest in this scenario, including C-reactive protein (CRP), white cell count, vesicoureteral reflux, fever, relative perfusion, and the presence of renal sequelae in a 6-month follow-up DMSA scan.

RESULTS

A fully automatic lesion detection and segmentation system was able to successfully classify DMSA-positive from negative scans (AUC=0.92, sensitivity=81% and specificity=94%). The image-computed relative size of the lesion correlated with the presence of fever and CRP levels (p<0.05), and a measurement derived from the distribution histogram of the lesion obtained significant performance results in the detection of permanent renal damage (AUC=0.86, sensitivity=100% and specificity=75%).

CONCLUSIONS

The proposal and implementation of a computational framework for the quantification of structural renal damage from DMSA scans showed a promising potential to complement visual diagnosis and non-imaging indicators.

A computational framework for cancer response assessment based on oncological PET-CT scans

In this work we present a comprehensive computational framework to help in the clinical assessment of cancer response from a pair of time consecutive oncological PET-CT scans. In this scenario, the design and implementation of a supervised machine learning system to predict and quantify cancer progression or response conditions by introducing a novel feature set that models the underlying clinical context is described. Performance results in 100 clinical cases (corresponding to 200 whole body PET-CT scans) in comparing expert-based visual analysis and classifier decision making show up to 70% accuracy within a completely automatic pipeline and 90% accuracy when providing the system with expert-guided PET tumor segmentation masks.

Tubeless percutaneous nephrolithotomy without losing the possibility of second-look nephroscopy: The perfect combination

OBJECTIVES

To evaluate an alternative approach to tubeless surgery that allows a second percutaneous procedure using the same nephrostomy tract.

METHODS

Twenty patients underwent percutaneous nephrolithotomy from September 2012 to May 2013 at our institution. Inclusion criteria were: absence of urinary infection, single puncture and operative time less than 2 h. Following the procedure the initially placed ureteral catheter was exteriorized through the working sheath by tying a non-absorbable suture to its end. On postoperative day 1 all patients were studied with non-enhanced CT or X-ray film. If the patient was rendered stone free, the stent was removed along with the urethro-vesical catheter. If a residual stone was present, we recovered the ureteral catheter and used the same nephrostomy tract for a second endoscopic procedure. Patients were assessed for pain, postoperative complications, length of stay, stone free rate, hematocrit and creatinine variations.

RESULTS

Thirteen patients met the inclusion criteria. No major complications related to the stent placement and its exteriorization were seen. Two patients required a second percutaneous procedure successfully achieved recovering the ureteral catheter through the nephrostomy tract.

CONCLUSION

We present a safe and simple modification of tubeless percutaneous nephrolithotomy, with its well-known clinical benefits but maintaining a safe path for an eventual second look procedure if necessary.

Evolution and genetic diversity of the Spain23F-ST81 clone causing adult invasive pneumococcal disease in Barcelona (1990-2012)

Objectives

We aimed to analyse the clinical epidemiology and genetic diversity of invasive pneumococcal disease (IPD) episodes attributed to the Spain^23F-ST81 (PMEN1) clone.

Methods

Fifty-eight (2.7%) of 2117 invasive pneumococci isolated from adult patients during the 1990–2012 period shared a PFGE pattern related to the PMEN1 clone. The genotype was confirmed by multilocus sequence typing. The pbp2x, pbp1a, pbp2b and pspA genes were PCR-amplified and sequenced. Polymorphisms in the pspC gene were identified by PCR restriction fragment length polymorphism. The presence of transposons with erythromycin and tetracycline resistance determinants was detected by PCR.

Results

The prevalence of the PMEN1 clone increased from 0.8% in 1991 to 6.2% in 2001, and decreased to 0% in 2010–12, concomitant with the introduction of the seven-valent pneumococcal conjugate vaccine for children. A total of 93.1% of patients had pneumonia, meningitis or peritonitis; 87.9% of patients had associated underlying diseases, mainly cancer, chronic obstructive pulmonary disease and diabetes. Two closely related sequence types (STs) (ST81, n = 52; ST85, n = 6) were detected, with different serotypes: 23F (n = 42), 19A (n = 9) and 19F (n = 6). All the isolates were resistant to penicillin, co-trimoxazole and chloramphenicol. All the isolates also shared the same pbp1a allele, whereas multiple alleles of pbp2b, pbp2x, pspA and pspC were detected. Of the isolates, 89.7% were tetracycline resistant and 60.3% (n = 35) were macrolide resistant, and resistance was associated with different Tn916-like transposons.

Conclusions

Adult IPD caused by this clone was mainly detected in patients with underlying conditions, and genetic variability was observed among PMEN1 isolates collected in our area over the past 20 years.

Comparison of two PCR and one ELISA techniques for the detection of small ruminant lentiviruses (SRLVs) in milk of sheep and goats

The aim of the present study was to compare the efficiency of two PCR techniques for the diagnosis of small ruminant lentiviruses (SRLVs). Detection of the proviral genome by PCR, though sensitive, is difficult due to the heterogeneity of the SRLV genomes. One of the PCR techniques amplifies a fragment in the pol gene (pol-PCR) and the other PCR targets the LTR region of the proviral genome (LTR-PCR). Milk from 194 sheep and 163 goats from farms in the Central Spain was analyzed by both techniques and compared to results obtained by ELISA. When compared to the serologic assay, the agreement of both PCR techniques was very low (0.024 and 0.020 in sheep, and 0.124 and 0.114 in goats). In view of these results, it may be concluded that the efficacy of PCR for the diagnosis of SRLVs is low and a combination of PCR and ELISA should be used for diagnosis.

[Benefits of epidural analgesia in major neonatal surgery]

The aim of this paper is to describe and evaluate the benefits of epidural anesthesia in major surgery neonatal. We have performed a matched case-control (2:1) study of patients undergoing neonatal major surgery (NMSs) who received intra-and postoperative epidural anesthesia (EA) and controls with conventional general anesthesia. The matching criteria were age, weight and baseline pathology. EA was administered by caudal puncture and epidural catheter placed with ultrasound support. Levobupivacaine was selected as anesthetic drug. The time to extubation, intestinal transit time, type of analgesia and complications were studied. This study is based on 11 cases (2 esophageal atresia, 2 diaphragmatic hernias, 1 necrotizing enterocolitis, 3 intestinal atresia, 2 anorectal malformation and 1 bladder exstrophy) and 22 controls. We observed statistically significant differences in time to extubation (95% CI OR 12 1.99 to 72.35; Chi2 p = 0.004, Mann U Whytney p = 0.013) and intestinal transit time (Mann Whitney U p < 0.001, 100 Or, 95% CI 8.06-1 239; Chi2 p < 0.0001). There were no complications from epidural analgesia. Therefore we believe that the intra-and postoperative EA helps improve postoperative management in neonates and should be preferred in centers where this technique is available.

[Single-session extracorporeal shock wave lithotripsy for urinary calculi: factors predicting success after three weeks of follow-up]

INTRODUCTION

The aim of this study was to identify predictive factors of success following a single-session of shock wave lithotripsy (SWL) at 3 weeks of follow-up in our center.

MATERIAL AND METHODS

The medical records of 116 patients with solitary urinary calculi who underwent single-session SWL in our department between October 2007 and August 2009 were reviewed. All preoperative unenhanced computed axial tomographies were reviewed by two radiologists blinded to clinical outcome. Success was defined as complete clearance or the persistence of fragments ≤ 2 mm on a plain film at 3 weeks of follow-up. The impact of clinical and radiological factors on success was assessed by univariate and multivariate analyses.

RESULTS

The single-session SWL success rate at 3 weeks was 49.1%. Stone size <8 mm, stone area < 30 mm(2), stone location (mid- and distal ureter), stone density <1000 HU and intraoperative fragmentation showed a significant association with SWL success in the univariate analysis (p<0.05). Stone area (OR 2.9), ureteral stone location (OR 3.4) and intraoperative fragmentation (OR 4.2) were the only predictors of success in the multivariate analysis.

CONCLUSIONS

Stone area and ureteral stone location provide important information when deciding about the indication of a SWL in a patient with stone disease. However, successful resolution of only half of the cases after a single session at 3 weeks in our series undermines the relevance of informing patients about the potential need for additional treatment.

Utilidad pronóstica de la gammagrafía con leucocitos marcados 99mTc-HMPAO en la enfermedad inflamatoria intestinal

OBJECTIVE

The inflammatory bowel disease (EII) has a chronic evolution with a frequent relapses. There is no specific diagnosis method to detect the patients with a high risk to relapse. The aim of the work was to analyse the prognostic value of 99mTc-HMPAO leukocyte scintigraphy (LS) performed during an acute attack of EII.

MATERIAL AND METHODS

18 patients (mean age 32 +/- 10 years) admitted for an acute attack of EII has been prospectively studied (5 ulcerative colitis [UC] and 13 Cronh's disease [CD]), excluding patient with prior steroids or immunosuppressive therapy during the last year. LS were obtained in basal conditions and following 3 weeks of steroid treatment and the scintigraphic activity index (SAI) has been calculated. Colonoscopy has been done in all patients, and CDAI in CD and Truelove index in UC have been calculated. Patients were followed up for 1 year. In the evolution the therapy requirements as well as the good response to initial treatment have been evaluated.

RESULTS

All patients with UC and 4 patients with CD showed a SAI decrease > 50 % and all had a good clinical evolution. Only 2 out of the 9 patients with CD showing a IAG decrease < 50 % and had a good clinical evolution, the 7 remaining required additional medical treatment (immunosuppressors or surgery).

CONCLUSION

LS may be of prognostic value in the management of EII. A SAI decrease > 50 % at 3 weeks of steroid treatment indicates a good clinical evolution.

Experimental Study of Clinafloxacin Alone and in Combination in the Treatment of Ciprofloxacin-Susceptible and -Resistant Pneumococcal Meningitis

The increasing incidence of ciprofloxacin resistance in Streptococcus pneumoniae may limit the efficacy of the new quinolones in difficult-to-treat infections such as meningitis. The aim of the present study was to determine the efficacy of clinafloxacin alone and in combination with teicoplanin and rifampin in the therapy of ciprofloxacin-susceptible and ciprofloxacin-resistant pneumococcal meningitis in rabbits. When used against a penicillin-resistant ciprofloxacin-susceptible strain (Clinafloxacin MIC 0.12 microg/ml), clinafloxacin at a dose of 20 mg/kg per day b.i.d. decreased bacterial concentration by -5.10 log cfu/ml at 24 hr. Combinations did not improve activity. The same clinafloxacin schedule against a penicillin- and ciprofloxacin-resistant strain (Clinafloxacin MIC 0.5 microg/ml) was totally ineffective. Our data suggest that a moderate decrease in quinolone susceptibility, as indicated by the detection of any degree of ciprofloxacin resistance, may render these antibiotics unsuitable for the management of pneumococcal meningitis.

Cellular distribution of bovine leukemia virus proteins gp51SU, Pr72(env), and Pr66(gag-pro) in persistently infected cells

Monoclonal antibodies (mAbs) against bovine leukemia virus (BLV) mature proteins and precursors were used to map the localization of these proteins in persistently infected non-lymphocytic cell lines using immunofluorescence assay (IFA) and immuno-electron microscopy. IFA staining was observed in the basolateral surface of live FLK-BLV cells. When using a mAb against Pr66(gag-pro), mottled pinpoint fluorescence was seen in the cell surface of polarized cells, but no reaction was observed in cells undergoing mitosis. However, a mAb against Pr72(env) stained only mitotic cells and cellular fragments. Additionally, in these dividing cells, this envelope (Env) precursor polyprotein was not evenly distributed but concentrated predominantly in only one daughter cell. To the best of our knowledge, this observation has not been reported previously, either for BLV or for other retroviruses. The results of immunogold electron microscopy confirmed the specificity of the mAbs in the intracellular level. In infected cells, Pr72(env) and gp51SU were seen in proximity at the plasma membrane in incipient budding sites. Additionally, the mAb against Pr72(env) also reacted with Env precursor polyproteins in the mitochondria of BLV-bat(2) ultrathin sections. These mAbs may be used as a tool for mapping virus excretion sites in the cell surface of naturally or in vitro infected cells in the different stages of the cell cycle.

Evaluation of virus excretion by cells persistently infected with the bovine leukaemia virus (BLV) using monoclonal antibodies

BACKGROUND

bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukaemia. Studies in vitro usually require the use of infected cell lines, mostly to produce antigen. Two of the most widely used cell lines are FLK-BLV and BLV-bat2.

OBJECTIVE

the dynamics of the excretion of BLV proteins and whole virus by the persistently BLV-infected cell lines mentioned above was studied using an indirect ELISA in combination with eight monoclonal antibodies (mAbs) and cow and rabbit serum.

STUDY DESIGN

tissue culture flasks were seeded with different concentrations of cells (13000-67000 cells per cm2, corresponding to 1-5 million cells per 75 cm2 flask) and were studied for 20 days. Samples (1.5 ml) were removed every 24 h and the presence of BLV proteins was determined using an indirect ELISA assay in which the antigen reaction with the monoclonal antibodies was evidenced by peroxidase labeled anti-mouse immunoglobulins.

RESULTS

cell line FLK-BLV produced a complete monolayer as early as 4 days after passage, 3 days earlier than BLV-bat2. Using mAbs, the amount of viral proteins in the supernatant showed a cyclic pattern, with two evident peaks at days ca. 8 and 16. These peaks occurred even in the absence of passage or medium change, which causes depletion of essential nutrients and acidity. In comparison to polyclonal serum, mAbs gave more clear and defined values and are useful for determining the dynamics of viral production.

CONCLUSION

when aiming for high viral yield, BLV should be harvested between days 6 and 8 after passage, when viral shedding is at its maximum. These results are very useful for preparing antigen for monoclonal antibody production, or for techniques such as ELISA or Western blot.

[Kidney and pancreas transplantation: initial experience at a single transplant center in Argentina]

After more than 10,000 cases reported all over the world until 1998, simultaneous kidney and pancreas transplantation has become a safe clinical practice, and it may probably represent the best treatment available for diabetic patients in end-stage renal disease. Here we present our results after 12 cadaveric pancreas transplants (8 whole organ, and 4 islet transplants), performed on insulin-dependent diabetic patients. Eleven of these patients received a kidney simultaneously, and one of them required a kidney retransplantation. All vascularised pancreatic grafts were positioned intraperitoneally, anastomosed to the iliac vessels, and bladder drained. One year patient, whole pancreas, and kidney survival rates were 86%, 86% and 71%, respectively. All of these patients remain insulin and dialysis-free, the longest for 37 months. Islets for transplantation were obtained from single cadaveric donors. Fresh, unpurified cells were transplanted intraperitoneally by laparoscopy (equivalent islet yields: 3 x 10(5), 4 x 10(5), 1 x 10(6) and 5 x 10(5)). None of the islet recipients resulted insulin-independent but they all reduced daily requirements in about 40%, with better metabolic control (mean HbA1c pretransplant 9.4 +/- 1.8, vs 7.9 +/- 1.6 posttransplant). One kidney graft was lost due to venous thrombosis. Simultaneous kidney and pancreas transplantation offers the diabetic patient in end-stage renal disease a chance of independence both from dialysis and exogenous insulin. Whole pancreas transplantation has better functional outcome than islet transplantation. Nevertheless, for those diabetic patients who do not meet the criteria to receive a vascularised graft, pancreatic cells may still improve carbohydrate metabolism with minor surgical risk.

Production and characterization of monoclonal antibodies against bovine leukaemia virus using various crude antigen preparations: a comparative study

A total of 59 monoclonal antibodies (mAbs) specific against the bovine leukaemia virus (BLV) using different antigen preparations was produced. The five antigen preparations for immunizing BALB/c mice were: live cells (CEL), sonicated and ultracentrifuged cells (SOC), cell lysates (LYS), semi-purified BLV (PV), and formalin-treated cells (FOR) from two cell lines permanently infected with BLV (FLK-BLV and BLV-bat2). These viral component presentations were selected to obtain mAbs against specific BLV proteins: located on the cell surface (FOR and CEL), in free virus particles (PV) and intracellular viral proteins (SOC and LYS). Two antigen preparations (SOC and LYS) were lethal to the mice following the intravenous and intrasplenic routes. Six fusions were performed in this study that rendered specific antibodies against BLV. The highest number of hybridomas was produced with SOC; however, the majority of the hybridomas produced (> 90%) were against cellular proteins. Even though immunization with PV gave the lowest number of hybridomas, the majority of them were specific against BLV. Based on the reactivity of the mAbs in Western blot (WB), we classified the mAbs into five groups, namely anti-gp51SU (39 mAbs), anti-gp30TM (six mAbs), anti-Pr72env (nine mAbs), anti-Pr66gag-pro (one mAb) and anti-Prgag (four mAbs). A very high percentage of the mAbs produced (48 of 59) reacted with gp51SU, suggesting that this is the most immunogenic and accessible BLV protein presented in the different antigen preparations. The majority of our mAbs recognized more than one band in WB, suggesting that, aside from reacting with mature proteins, the mAbs also recognized viral precursors.

Rapid detection of specific polyclonal and monoclonal antibodies against bovine leukemia virus

ELISA and Western blot have been used for detecting specific antibodies or antigens for routine diagnostic laboratory tests and experimental protocols, as well as for screening hybridomas secreting antibodies. Although these techniques are sensitive, some slow growing hybridomas are identified as positive only when they are grown slowly long time. We standardized the dot-ELISA, a more sensitive technique, for the detection of antibodies against BLV. The main advantages of the dot-ELISA described in this study are (a) its sensitivity, detecting hybridomas which would otherwise be considered negative and discarded from the results of indirect ELISA and/or Western blot; and (b) the possibility of economizing reagents using as little as 1 microl of the antigen and 0.5 microl of antibody and conjugate. Different BLV-antigen preparations were bound to nitrocellulose membranes (NC), including cells lysed chemically (LYS) or by sonication (SOC), semi-purified virus (PV), and supernatant from infected cultures, either without treatment (SUP) or sonicated (SOS). The antigen preparations most adequate for detecting monoclonal antibodies against BLV and polyclonal antibodies in cattle sera were undiluted cell lysates (LYS) and semi-purified BLV (PV). When testing bovine sera, the supernatant (SUP) and sonicated supernatant (SOS) antigens gave a high background due to the presence of FCS which reacted with the anti-bovine labeled antibodies. In this study, 59 BLV specific antibody secreting hybridomas were identified using the dot-ELISA, compared to only 20 detected using iELISA, and doubtful reactions due to nonspecific binding to fetal calf serum (FCS) and cellular components were measured. The results of the improved dot-ELISA described may be stored at room temperature for future reference. Results were consistently reproducible in coated nitrocellulose membranes kept at different storage temperatures (-20 degrees C, 4 degrees C, and 25-30 degrees C) 48 h, 1 week and 5 months.

Development of a PCR assay for detection of Yersinia ruckeri in tissues of inoculated and naturally infected trout

A PCR-based method was developed for the specific detection of Yersinia ruckeri in tissues of inoculated trout and naturally infected trout. No amplification products were obtained with other yersiniae, bacterial fish pathogens, or phylogenetically related bacteria (n = 34). The sensitivity of PCR detection was 60 to 65 bacterial cells per PCR tube, which was decreased to 10 to 20 cells by hybridization with a nonradioactive probe. The PCR assay proved to be as reliable as and faster than the conventional culture method for the detection of Y. ruckeri in infected trout tissues.

[Seroprevalence of Legionella pneumophila infection in healthy, adults from Santiago, Chile]

In order to investigate the L pneumophila seroprevalence in healthy adult population of Santiago, Chile, a serologic survey of antibodies to serogroups 1 through G was performed. Sera of 100 blood donors were studied with the indirect fluorescent antibody method. Positive results (> or = 1.64) were obtained in five samples. Titres > or = 1:128 were not observed. We conclude that the seroprevalence of L pneumophila in Santiago is 5% and that a single titre > or = 1:256 suggests the diagnosis of legionellosis. The low seroprevalence in Santiago is in agreement with the few cases of legionellosis reported.

Determination of the reactivities and cross-reactivities of monoclonal antibodies against staphylococcal enterotoxin A by indirect ELISA and immunoblot including a semiautomated electrophoresis system

Eight murine monoclonal antibodies (Mabs) to staphylococcal enterotoxin A (SEA) were produced using standard hybridoma techniques. We studied reactivities and cross-reactivities by indirect ELISA and immunoblotting. Two of these Mabs (A5 and A7) reacted with five serovars (A-E) of SE in both systems. Only Mab A1 reacted specifically with the homologous toxin, while four Mabs reacted with SEA and SEE. Mabs A5 and A7 could be used to detect all five serovars of SEs in a single assay.

Production of staphylococcal enterotoxins and TSST-1 by coagulase negative staphylococci isolated from ruminant mastitis

The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin-1 by 40 coagulase negative staphylococci isolated from sheep, goat and cow mastitis was studied. Both ELISA double sandwich and Western blot were used to detect the production of these toxins. Only two strains of S. xylosus were enterotoxigenic, producing SEC. TSST-1 was seen to be produced by 5 strains of S. xylosus, 1 S. sciuri and 2 S. epidermidis. Results obtained by ELISA and by Western blot agreed in all cases except in one strain of S. epidermidis which was only positive using ELISA.

Effect of six organic acids on staphylococcal growth and enterotoxin production

Four Staphylococcus aureus strains were incubated at 37 degrees C for 24 h in broth progressively acidified with lactic, citric, ascorbic, acetic, pyruvic and propionic acids, and their survival rate and enterotoxin producing ability was studied. Acids were chosen based on their frequent use by the food industry. Periodically, samples were withdrawn to determine counts, pH and the presence of enterotoxins A, B, C, and D. For a given acid, the effect on growth and enterotoxin synthesis was different. The most inhibitory acid for the growth of strains FRI-100 and FRI-472 was pyruvic acid, for strain FRI-137 was lactic acid, all six acids were equally effective on strain S6. Lactic acid was very inhibitory to enterotoxin synthesis, but the effect on this parameter of acetic and citric acids was almost nil. Enterotoxins were seen to be inactivated at acid pH values; enterotoxin B was the most resistant to inactivation.

Growth of Staphylococcus aureus and synthesis of enterotoxin during ripening of experimental Manchego-type cheese

To study the possible presence of staphylococcal enterotoxins in Manchego-type cheese, milk was inoculated with the enterotoxigenic Staphylococcus aureus collection strains FRI-100, S6, FRI-137, and FRI-472 to a final concentration of 10,000 to 25,000 cfu/ml. Cheese was prepared following the industrial specifications and ripened for 60 d. Batches were prepared with 1 and .1% lactic acid culture and labeled with the abbreviated name of the strain and the concentration of lactic acid culture. Mean staphylococcal counts in .1% lactic bacteria cheeses were usually more than 1 log higher than the corresponding 1% ones. Staphylococcal counts declined markedly after d 35 to 42, and, by the end of ripening, they had disappeared from some cheeses. Enterotoxins were present in five of the cheeses, three prepared with .1% and two with 1% lactic bacteria. Enterotoxins detected were A and D, the enterotoxins most commonly associated with human intoxication. The maximum level of enterotoxin A detected in cheese with strain FRI-100 and with the .1% culture was 222 ng/100 g of cheese; in cheese FRI-100 with 1%, 111 ng/100 g; in cheese S6 with .1%, 769 ng/100 g; and in cheese S6 with 1%, 33 ng/100 g. Maximum level of enterotoxin D detected in cheese FRI-472 with .1% was 38 ng/100 g.