Cost-minimization analysis of oral versus intravenous antibiotic treatment for Klebsiella pneumoniae liver abscess.

A cost-minimization analysis was conducted for Klebsiella pneumoniae liver abscess (KLA) patients enrolled in a randomized controlled trial which found oral ciprofloxacin to be non-inferior to intravenous (IV) ceftriaxone in terms of clinical outcomes. Healthcare service utilization and cost data were obtained from medical records and estimated from self-reported patient surveys in a non-inferiority trial of oral ciprofloxacin versus IV ceftriaxone administered to 152 hospitalized adults with KLA in Singapore between November 2013 and October 2017. Total costs were evaluated by category and payer, and compared between oral and IV antibiotic groups over the trial period of 12 weeks. Among the subset of 139 patients for whom cost data were collected, average total cost over 12 weeks was $16,378 (95% CI, $14,620-$18,136) for the oral ciprofloxacin group and $20,569 (95% CI, $18,296-$22,842) for the IV ceftriaxone group, largely driven by lower average outpatient costs, as the average number of outpatient visits was halved for the oral ciprofloxacin group. There were no other statistically significant differences, either in inpatient costs or in other informal healthcare costs. Oral ciprofloxacin is less costly than IV ceftriaxone in the treatment of Klebsiella liver abscess, largely driven by reduced outpatient service costs.Trial registration: ClinicalTrials.gov Identifier NCT01723150 (7/11/2012).

Assessment of corn wet distillers grains fed to crossbred bulls on feeding behavior, rumen morphology, liver abscesses and blood parameters.

Corn ethanol production has been growing in Brazil in the last ten years, generating by-products to feedlot diets. This study evaluates the effects of the inclusion of low-fat corn wet distillers grains (LF-WDG) on feeding behavior, ruminal health, liver abscesses and blood parameters of F1 Angus-Nellore bulls feedlot finished. Our hypothesis is that evaluation of data from feeding behavior, rumen and liver health would help to explain animal performance. In this trail, one-hundred animals were fed for 129 days with diets containing amounts of 0 (control), 15, 30 and 45% of LF-WDG replacing corn grain and soybean meal. Evaluations of fluctuation of dry matter intake (DMI) were carried out. Additionally, feeding behavior data were assessed by monitoring (24-h period) the feeding, rumination, time spent eating (TSE), and time expended on other activities (resting and number of meals per day). Blood variables such as pH, bicarbonate, total CO2 content, and base excess in extracellular fluid (Beecf) were determined. After slaughter, rumen epithelium was classified according to the incidence of lesions (rumenitis) and abnormalities (papillae clumped), and samples were collected for morphology and histology evaluations. Moreover, livers were scored for severity of abscesses as follow: as unabscessed (0), one or two small abscesses (A-), two to four small active abscesses (A) or one or more large, active abscesses (A+). The DMI (kg/day) differed (P = 0.03) among treatments and there is a tendency of 15 and 30 LF-WDG (% DM) had lower %DMI fluctuation compared to 0 or 45%. The TSE increased linearly (P < 0.01) as the amounts of inclusion of LF-WDG increased. Moreover, neutral detergent fiber (NDF) intake, NDF consumption rate and NDF rumination efficiency increased linearly (P < 0.01) in response to LF-WDG feeding. The incidence of rumenitis tended (P = 0.08) to be greater at 45% LF-WDG, while keratin thickness decreased linearly in bulls fed LF-WDG (P < 0.01). The severity of liver abscesses (score A+) increased linearly (P = 0.02). Regarding blood parameters, only Beecf decreased linearly (P < 0.01) in response to LF-WDG feeding. Therefore, the hypothesis of the current study was confirmed. We previous reported that F1 Angus-Nellore bulls fed LF-WDG show greater weight gain (1.94 ± 0.09 kg/day) and final body weight (620 ± 18.8 kg) when compare to control (1.8 ± 0.09 kg/day and 602 ± 18.8 kg, respectively). Here, we conclude that inclusion of 15 to 30% LF-WDG in feedlot diets improved feeding behavior without impairing ruminal health and blood parameters, driving performance and weigh gain of crossbred bulls. However, bulls fed 45% LF-WDG had greater severity of liver abscesses.

An assessment of the effectiveness of virginiamycin on liver abscess incidence and growth performance in feedlot cattle: a comprehensive statistical analysis.

The judicious use of commercial products in livestock operations can be part of a sustainable and environmentally friendly production scenario. This study was designed to gather published data of virginiamycin (VM) used in feedlot conditions of the United States and analyze its effectiveness and optimum dosage in reducing the liver abscess incidence (LAI). The dataset contained 26 studies that evaluated more than 7,156 animals of diverse breeds fed in several regions in the United States under different management. Statistical analyses included contingency tables to assess the nonparametric independence of the LAI, meta regression analysis to remove study effects and to evaluate LAI and animal performance, broken-line analysis to determine thresholds of VM dosage on LAI, and residual-based shading mosaic plots to illustrate the contingency analysis. There were 1,391 of 5,430 animals with LAI scores 1, 2, or 3 (LAI1-3) and 651 of 4,690 animals with LAI A+ (score 3). Our analyses suggested that there was a significant dependency (χ2P-value < 0.001) and significant asymmetry (McNemar's test P-value < 0.001) between LAI and VM treatment for both LAI1-3 and LAI A+. For the LAI1-3 group, only 22.5% of the treated animals had liver abscesses compared with 31.7% of the control animals. The metaregression analysis indicated that LAI1-3 was linearly reduced (P < 0.001) by about 0.42% per mg/kg of DM of VM. The lower 95% confidence interval of the intercept for LAI1-3 and LAI A+ obtained with a generalized nonlinear mixed regression was 18.7 and 20.3 mg/kg of DM, respectively. The broken-line regression analysis identified 2 thresholds for LAI (23.9 and 12.3 mg/kg of DM) at which the reduction in total LAI1-3 and LAI A+, respectively, would decrease faster as VM dosage increases (from 2.14% to 6% and from 1.91% to 4.33% per mg of VM per kg of DM, respectively). Additionally, our analyses indicated that after accounting for the study effects, VM significantly increased ADG at 2.08 g BW/d per mg/kg DM compared with 0.92 g BW/d per mg/kg DM for monensin (P < 0.001), suggesting that VM was about 2.3 times more effective in increasing ADG for the same dosage and feeding period length. All analyses yielded consistent results that led us to conclude that VM is effective in reducing LAI when fed between approximately 12 and 24 mg/kg of DM, and the maximum reduction might occur at approximately 24 mg/kg of DM or higher.

Burden of Liver Abscess and Survival Risk Score in Thailand: A Population-Based Study.

In Thailand, the burden of liver abscess, a life-threatening infectious disease, has not been thoroughly evaluated. We developed a predictive scoring system to estimate survival of patients with liver abscess using information from the 2008-2013 Nationwide Hospital Admission Data to evaluate the burden of liver abscess in Thailand. All patients with primary diagnosis of pyogenic liver abscess (PLA) and amoebic liver abscess (ALA) were included. Epidemiological data, baseline characteristics, hospital course, and survival were analyzed. Overall, 11,296 admissions comprising 8,423 patients from 844 hospitals across Thailand were eligible for analysis. The mean age was 52 ± 17 years and 66.1% of patients were male. ALA was significantly prevalent in southern and western border regions of Thailand, and PLA occurred nationwide. The highest incidence of liver abscess occurred in the rainy season (June-November, P < 0.01). The median length of hospital stay was 8 days (interquartile range = 4-13 days), and mean direct cost of hospitalization was 846 ± 1,574 USD. The overall inhospital mortality rate was 2.8%. Incidence of ALA decreased over the 5-year study period, whereas PLA incidence increased (P < 0.01). Using multivariable Cox regression methods with stepwise variable selection, we developed a final model with five highly significant baseline parameters associated with increased 60-day mortality: older age, PLA, underlying chronic kidney disease, cirrhosis, and human immunodeficiency virus infection. Range of estimated probability of 60-day survival was 95-16% at cumulative risk score 0-13. This simplified score is practical, and may help clinicians prioritize patients requiring more intensive care.

Clinical characteristics and economic consequence of Klebsiella pneumoniae liver abscess in Taiwan.

BACKGROUND: Klebsiella pneumoniae liver abscess (KPLA) has emerged as an endemic disease in Taiwan, and its prevalence has been increasing in east Asian countries in the past three decades. The utilization of healthcare resources associated with KPLA is assumed to be substantial, and may be of future concern. This study investigated the clinical characteristics and economic burden of KPLA in Taiwan in 2011 and 2012. METHODS: Adult patients with KPLA were identified retrospectively in a tertiary medical center in Taiwan from January 2011 to December 2012. The clinical characteristics, total and daily hospitalization expenditure, and the risk factors for the costs of KPLA were analyzed. RESULTS: Among patients with KPLA, the median cost was $5290.80 in US dollars, and the mean cost was $6337.50 ± $4363.40. Length of hospital stay was the only independent risk factor for the high total hospitalization expenditure. The duration of antibiotic use was nearly the same as the length of hospital stay. The prolonged stay in the general ward (≥21 days) also contributed to the high total cost of hospitalization. The independent risk factors for the high average daily cost of hospitalization were a higher Charlson Comorbidity Index and the requirement of intensive care on admission. CONCLUSION: The current study is the first to demonstrate the high economic burden resulting from KPLA in a medical center in Taiwan. Standardizing the treatment protocol for KPLA inpatients and introducing an outpatient parenteral antimicrobial therapy center to reduce the length of stay may reduce costs, whereas development of a vaccine may be necessary to tackle endemic KPLA in the future.

Oral versus intravenous antibiotics for patients with Klebsiella pneumoniae liver abscess: study protocol for a randomized controlled trial.

BACKGROUND: Klebsiella pneumoniae liver abscess is the most common etiology of liver abscess in Singapore and much of Asia, and its incidence is increasing. Current management includes prolonged intravenous antibiotic therapy, but there is limited evidence to guide oral conversion. The implicated K1/K2 capsule strain of Klebsiella pneumoniae is almost universally susceptible to ciprofloxacin, an antibiotic with high oral bioavailability. Our primary aim is to compare the efficacy of early (< one week) step-down to oral antibiotics, to continuing four weeks of intravenous antibiotics, in patients with Klebsiella liver abscess. METHODS/DESIGN: The study is designed as a multi-center randomized open-label active comparator-controlled non-inferiority trial, with a non-inferiority margin of 12%. Eligible participants will be inpatients over the age of 21 with a CT or ultrasound scan suggestive of a liver abscess, and Klebsiella pneumoniae isolated from abscess fluid or blood. Randomization into intervention or active control arms will be performed with a 1:1 allocation ratio. Participants randomized to active control will receive IV ceftriaxone 2 grams daily to complete a total of four weeks of IV antibiotics. Participants randomized to intervention will be immediately converted to oral ciprofloxacin 750 mg twice daily. At Week four, all participants will undergo abdominal imaging and be assessed for clinical response (CRP < 20 mg/l, absence of fever, plus scan showing that the maximal diameter of the abscess has reduced). If criteria are met, antibiotics are stopped; if not, oral antibiotics are continued, with reassessment for clinical response fortnightly. If criteria for clinical response are met by Week 12, the primary endpoint of clinical cure is met. A cost analysis will be performed to assess the cost saving of early conversion to oral antibiotics, and a quality of life analysis will be performed to assess whether treatment with oral antibiotics is less burdensome than prolonged IV antibiotics. DISCUSSION: Our results would help inform local and international practice guidelines regarding the optimal antibiotic management of Klebsiella liver abscess. A finding of non-inferiority may translate to the wider adoption of a more cost-effective strategy that reduces hospital length of stay and improves patient-centered outcomes and satisfaction. TRIAL REGISTRATION: Clinical trials gov NCT01723150.

Assessment of hypermucoviscosity as a virulence factor for experimental Klebsiella pneumoniae infections: comparative virulence analysis with hypermucoviscosity-negative strain.

BACKGROUND: Klebsiella pneumoniae displaying the hypermucoviscosity (HV) phenotype are considered more virulent than HV-negative strains. Nevertheless, the emergence of tissue-abscesses-associated HV-negative isolates motivated us to re-evaluate the role of HV-phenotype. RESULTS: Instead of genetically manipulating the HV-phenotype of K. pneumoniae, we selected two clinically isolated K1 strains, 1112 (HV-positive) and 1084 (HV-negative), to avoid possible interference from defects in the capsule. These well-encapsulated strains with similar genetic backgrounds were used for comparative analysis of bacterial virulence in a pneumoniae or a liver abscess model generated in either naïve or diabetic mice. In the pneumonia model, the HV-positive strain 1112 proliferated to higher loads in the lungs and blood of naïve mice, but was less prone to disseminate into the blood of diabetic mice compared to the HV-negative strain 1084. In the liver abscess model, 1084 was as potent as 1112 in inducing liver abscesses in both the naïve and diabetic mice. The 1084-infected diabetic mice were more inclined to develop bacteremia and had a higher mortality rate than those infected by 1112. A mini-Tn5 mutant of 1112, isolated due to its loss of HV-phenotype, was avirulent to mice. CONCLUSION: These results indicate that the HV-phenotype is required for the virulence of the clinically isolated HV-positive strain 1112. The superior ability of the HV-negative stain 1084 over 1112 to cause bacteremia in diabetic mice suggests that factors other than the HV phenotype were required for the systemic dissemination of K. pneumoniae in an immunocompromised setting.

Transgastric transhepatic endosonography-guided biliary drainage: histological assessment of its sinus tract in an autopsy case.

Endosonography-guided biliary drainage (ESBD) is gaining attention as a promising drainage technique for obstructive jaundice. However, histological changes resulting from ESBD have not been well understood. We had an opportunity to histologically investigate the influence of ESBD, established between the left hepatic duct and the stomach, on the relevant organs in an autopsy case with bile duct cancer extending from the pancreatic head to the hepatic hilum with duodenal invasion. Localized fibrous connective tissues were present around and along the sinus tract, including the connection between the surfaces of the left lobe of the liver and the gastric serosa, without hemorrhage, inflammatory changes, or cancer invasion. The inside of the ESBD stent was slightly stenotic at the intramural portion of the stomach due to proliferation of granulation tissue. No bile stasis or abscess was observed in the left lobe. These results are quite suggestive of the high safety and efficacy of ESBD with adequate performance.

[Accuracy of liver lesion assessment using automated measurement and segmentation software in biphasic multislice CT (MSCT)]. / Einfluss des vaskularisationsgrades auf die automatische segmentierung und messung von lebertumoren nach RECIST in einer biphasischen multi-slice-CT (MSCT).

PURPOSE: To assess the accuracy of liver lesion measurement using automated measurement and segmentation software depending on the vascularization level. MATERIALS AND METHODS: Arterial and portal venous phase multislice CT (MSCT) was performed for 58 patients. 94 liver lesions were evaluated and classified according to vascularity (hypervascular: 13 hepatocellular carcinomas, 20 hemangiomas; hypovascular: 31 metastases, 3 lymphomas, 4 abscesses; liquid: 23 cysts). The RECIST diameter and volume were obtained using automated measurement and segmentation software and compared to corresponding measurements derived visually by two experienced radiologists as a reference standard. Statistical analysis was performed using the Wilcoxon test and concordance correlation coefficients. RESULTS: Automated measurements revealed no significant difference between the arterial and portal venous phase in hypovascular (mean RECIST diameter: 31.4 vs. 30.2 mm; p = 0.65; kappa = 0.875) and liquid lesions (20.4 vs. 20.1 mm; p = 0.1; kappa = 0.996). The RECIST diameter and volume of hypervascular lesions were significantly underestimated in the portal venous phase as compared to the arterial phase (30.3 vs. 26.9 mm, p = 0.007, kappa = 0.834; 10.7 vs. 7.9 ml, p = 0.0045, kappa = 0.752). Automated measurements for hypovascular and liquid lesions in the arterial and portal venous phase were concordant to the reference standard. Hypervascular lesion measurements were in line with the reference standard for the arterial phase (30.3 vs. 32.2 mm, p = 0.66, kappa = 0.754), but revealed a significant difference for the portal venous phase (26.9 vs. 32.1 mm; p = 0.041; kappa = 0.606). CONCLUSION: Automated measurement and segmentation software provides accurate and reliable determination of the RECIST diameter and volume in hypovascular and liquid liver lesions. Hypervascular lesions are prone to be underestimated with regard to size in the portal venous phase and therefore should preferentially be segmented in the arterial phase.

Closed drainage of liver abscesses: the 'UNICAL' drain as an efficient and cost saving device in a tropical setting.

INTRODUCTION: Liver abscesses occur in both the developed and developing countries. Up to the time of this study lever abscesses in our centre were drained with open laparotomy, because of the lack of standard equipment for percutaneous drainage. We present a preliminary report of six cases of liver abscesses drained percutaneously using the 'UNICAL' closed drainage system. METHODOLOGY: Six patients all males aged 23 54 years were treated for liver abscesses using the 'UNICAL' drain (a locally devised active drain system), under ultrasound guidance. Five of the patients had amoebic abscesses, all located in the right hepatic lobe. The sixth patient had multiple pyogenic abscesses involving both hepatic lobes. The six patients had pre and post-drainage antimicrobial therapy for a total of two weeks. RESULTS: One patient, who was a diabetic, had a recollection of pus within a week after the initial drainage. He was redrained with the same device with complete cure. Full blood count and liver function tests showed anaemia (haemoglobin < 10 g/dl), leucocytosis and hyperbilirubinaemia in five patients. CONCLUSION: We conclude that the 'UNICAL' drain is an effective and cheap device for percutaneous drainage of liver abscess under ultrasound guidance in a'resource poor environment'.

Use of second generation contrast-enhanced ultrasound in the assessment of focal liver lesions.

Ultrasound (US) is often the first imaging modality employed in patients with suspected focal liver lesions. The role of US in the characterisation of focal liver lesions has been transformed with the introduction of specific contrast media and the development of specialized imaging techniques. Ultrasound now can fully characterise the enhancement pattern of hepatic lesions, similar to that achieved with contrast enhanced multiphasic computed tomography (CT) and magnetic resonance imaging (MRI). US contrast agents are safe, well-tolerated and have very few contraindications. Furthermore, real-time evaluation of the vascularity of focal liver lesions has become possible with the use of the newer microbubble contrast agents. This article reviews the enhancement pattern of the most frequent liver lesions seen, using the second generation US contrast media. The common pitfalls for each type of lesion are discussed. The recent developments in US contrast media and specific imaging techniques have been a major advance and this technique, in view of the intrinsic advantages of US, will undoubtedly gain popularity in the years to come.

[Percutaneous, laparoscopic and open surgical radiofrequency ablation of malignant liver lesions]. / Interventionelle, laparoskopische und offen operative Radiofrequenztherapie maligner Leberläsionen.

The growing clinical impact of radiofrequency ablation of liver lesions is reflected by a rapidly increasing number of published papers. Experimental work focuses on factors that reduce the variability of the ablation zone. The Pringle-maneuver plays a key role in this question from a surgeon's perspective. Large single center studies and a meta-analysis show a sharp rise in the rate of local recurrences for tumors larger 3 cm. An open surgical approach is significantly correlated to a low local recurrence rate. Bile duct lesions and intrahepatic abscesses are the most frequent complications. Intraductal bile duct cooling can prevent these complications. Three prospective randomized trials support the use of RFA for small hepatocellular carcinoma. The use of RFA in patients with multiple colorectal metastases is supported by single center studies showing a 3 year survival of > 35%. The favourable cost / benefit ratio will make RFA a part of future multimodal cancer therapy concepts.

Assessment of early biliary complications after orthotopic liver transplantation and their relationship to the technique of biliary reconstruction.

INTRODUCTION: Biliary complications are known as the weak point of liver transplantation. Their occurrence can be related to the practice of drainage of the biliary anastomosis, the routine use of which was abandoned in June 2004. The aim of the study was to assess the incidence and type of biliary complications following orthotopic liver transplantation in relation to the technique of biliary anastomosis. MATERIAL AND METHODS: We compared the results of two groups of adult liver transplant recipients: group I, recent 50 transplantations with biliary drainage (25 women: 25 men of age range: 17 to 63 years), and group II, first 50 transplantations without drainage (19 women and 31 men of age range, 20 to 65 years). We examined the problem of biliary complications and their influence on the further management of the patients. In both groups the main indications for transplantation were various types of cirrhosis as well as cholestatic diseases. In the majority of cases (n = 86) an end-to-end common bile duct anastomosis was performed and in 14 cases, hepaticojejunal anastomosis. RESULTS: In group I, biliary complications requiring surgical or endoscopic intervention occurred in 10 (20%) recipients. In one case, biliary complications resulted in the need for retransplantation. In group II, biliary complications occurred in only four (8%) patients, none of which caused organ loss. CONCLUSION: Cessation of biliary anastomosis drainage has reduced the occurrence of early biliary complications following orthotopic liver transplantation.

Patient-physician discordance about benefits and risks in gastroenterology decision-making.

AIMS: To illustrate the characteristics of situations in gastroenterology when patients and physicians harbour different perspectives of medical costs and benefits, and how such different perspectives affect the outcome of medical decision-making. METHODS: Two exemplary scenarios are presented, in which threshold analysis yields different results depending on the varying values assigned to identical medical events. The occurrence of varying values is subsequently phrased in economical terms of varying utility functions that characterize patient vs. physician behaviour. RESULTS: Safety and therapy are the two major preferences that determine patient and physician utility functions. Patients and physicians make medical decisions based on two different utility functions. In comparison with their patients, gastroenterologists are more concerned with safety and inclined to spend more health care resources on safety than therapy because safety and the occurrence of medical complications affect their own professional status. In trying to maximize their own utility, gastroenterologists tend to spend more resources on safety than the patient him/herself might have spent given a free choice of management options. CONCLUSIONS: In instances of potential complications associated with risky medical interventions, patients may receive less medical therapy in exchange for more procedural safety.

Twenty years of percutaneous treatments for cystic echinococcosis: a preliminary assessment of their use and safety.

Image-guided percutaneous treatments for echinococcal cysts were introduced in the mid-eighties. Today they represent a third therapeutic option, after surgery and benzimidazole derivatives. Two types of percutaneous treatments are available, based on the destruction of the germinal layer or the evacuation of the endocyst. To assess the extent of their use and their safety, a Medline search of the literature on this subject was performed. The number of cysts treated, their anatomical sites, the complications and, length of follow-up (when available), were all examined. The results show that percutaneous treatments for cystic echinococcosis are safe and efficacious in selected anatomical sites, provided basic safety issues are correctly addressed. However, before drawing final conclusions, a more detailed analysis of the literature is needed. Percutaneous treatments could be simplified and made more effective if a scolecidal agent could be found that melts the entire endocyst without causing harm to the biliary epithelium.

Sequential intravenous/oral antibiotic vs. continuous intravenous antibiotic in the treatment of pyogenic liver abscess.

AIM: Pyogenic liver abscesses result in substantial morbidity and mortality. Antimicrobial regimens using sequential intravenous/oral therapy may reduce the length of hospital stay. In this retrospective analysis, the efficacy of continuous intravenous antibiotic therapy (group I) vs. sequential intravenous/oral antibiotic therapy (group II) was studied in patients with pyogenic liver abscess. METHODS: One hundred and twelve consecutive patients (55 in group I and 57 in group II) with pyogenic liver abscess were analysed. Clinical response, length of hospital stay and relapse rates were examined. RESULTS: Group II had a significantly shorter duration of intravenous antibiotic treatment (3.2 weeks vs. 5.9 weeks, P < 0.01) and a shorter length of hospital stay (28 days vs. 42 days, P < 0.01) when compared to group I. Oral antibiotics were prescribed for a median duration of 2.9 weeks in group II after discharge. No relapse occurred within 6 weeks after the completion of treatment in both groups. The cost of therapy was significantly lower in group II than in group I by 33%. CONCLUSIONS: A sequential intravenous/oral antibiotic regime is a safe and effective treatment for pyogenic liver abscess. This reduces the cost of therapy and the length of hospital stay.

Sequential use of gadolinium chelate and mangafodipir trisodium for the assessment of focal liver lesions: initial observations.

The purpose of this study was to assess the feasibility of sequential administration of 2 different MR imaging contrast agents using a single visit protocol to image focal liver abnormalities. Twenty-one patients with known or suspected liver lesions were included in the study. All patients received a bolus intravenous injection of gadolinium chelate (Gd) and dynamically enhanced imaging performed. The patients then received an injection of mangafodipir trisodium (Mn) contrast and a second scan performed with an average delay of 62 min after the Gd bolus injection. The images were evaluated to determine the appearance of liver lesions after administration of each contrast agent, and for evidence of prior Gd administration adversely affecting evaluation of images acquired after Mn administration. Focal liver lesions were present in 19 patients, including 8 with liver metastases, 1 with liver lymphoma, 6 with hemangiomas, 3 with focal nodular hyperplasia (FNH), and 1 with hepatic abscess. In 2 other patients no liver lesions were identified in either the post-Gd or post-Gd-post-Mn scans. All malignant lesions identified on the post-Gd scan were also identified on post-Gd-post-Mn scans. Although the potential benefit for increasing detection sensitivity for hepatic metastases was not demonstrated, this is a preliminary series. This study does demonstrate the practicality for use a single visit sequential Gd-Mn protocol described here, with possible application of this technique for further assessment of the utility of combining Gd and Mn for detection of liver metastases.

Liver abscesses in feedlot cattle: a review.

Liver abscesses in slaughtered beef cattle result from aggressive grain-feeding programs. The incidence, averaging from 12 to 32% in most feedlots, is influenced by a number of dietary and management factors. Liver abscesses represent a major economic liability to producers, packers, and ultimately consumers. Besides liver condemnation, economic impacts include reduced feed intake, reduced weight gain, decreased feed efficiency, and decreased carcass yield. Fusobacterium necrophorum, a member of the ruminal anaerobic bacterial flora, is the primary etiologic agent. Actinomyces pyogenes is the second most frequently isolated pathogen. Ruminal lesions resulting from acidosis generally are accepted as the predisposing factors for liver abscesses. F. necrophorum possesses or produces a number of virulence factors that participate in the penetration and colonization of the ruminal epithelium and subsequent entry and establishment of infection in the liver. However, only a few virulence factors have been characterized well. Control of liver abscesses in feedlot cattle generally has depended on the use of antimicrobial compounds. Five antibiotics (i.e., bacitracin methylene disalicylate, chlortetracycline, oxytetracycline, tylosin, and virginiamycin) are approved for prevention of liver abscesses in feedlot cattle. Tylosin is the most effective and the most commonly used feed additive. Tylosin feeding reduces abscess incidence by 40 to 70%. The mode of action of antibiotics in preventing liver abscesses is believed to be via inhibition of ruminal F. necrophorum. Protective immunity against F. necrophorum induced by a variety of antigenic components has ranged from ineffectual to significant protection.