Development of an experimental model for liver abscess induction in Holstein steers using an acidotic diet challenge and bacterial inoculation.

Holstein steers (n = 40; initial BW = 84.9 ±â€…7.1 kg) were used to study the genesis of liver abscesses (LA) using an acidotic diet challenge with or without intraruminal bacterial inoculation. Steers were housed in individual pens inside a barn and randomly assigned to one of three treatments: (1) low-starch control diet comprised primarily of dry-rolled corn and wet corn gluten feed (CON); (2) high-starch acidotic diet with steam-flaked corn (AD); or (3) acidotic diet plus intraruminal inoculation with Fusobacterium necrophorum subsp. necrophorum (9.8 × 108 colony forming units [CFU]/mL), Trueperella pyogenes (3.91 × 109 CFU/mL), and Salmonella enterica serovar Lubbock (3.07 × 108 CFU/mL), previously isolated from LA (ADB). Steers in AD and ADB were fed the acidotic diet for 3 d followed by 2 d of the CON diet, and this cycle was repeated four times. On day 23, ADB steers were intraruminally inoculated with the bacteria. At necropsy, gross pathology of livers, lungs, rumens, and colons was noted. Continuous data were analyzed via mixed models as repeated measures over time with individual steer as the experimental unit. Mixed models were also used to determine the difference in prevalence of necropsy scores among treatments. Ruminal pH decreased in AD and ADB steers during each acidotic diet cycle (P ≤ 0.05). LA prevalence was 42.9% (6 of 14) in ADB vs. 0% in AD or CON treatments (P < 0.01). Ruminal damage was 51.1% greater in ADB than in AD (P ≤ 0.04). Culture of LA determined that 100% of the abscesses contained F. necrophorum subsp. necrophorum, 0% contained T. pyogenes, 50% contained Salmonella, and 50% contained a combination of F. necrophorum subsp. necrophorum and Salmonella. The F. necrophorum subsp. necrophorum was clonally identical to the strain used for the bacterial inoculation based on phylogenetic analysis of the whole genome. This experimental model successfully induced rumenitis and LA in Holstein steers and confirms the central dogma of LA pathogenesis that acidosis and rumenitis lead to the entry of F. necrophorum into the liver to cause abscesses. Our findings suggest that an acidotic diet, in conjunction with intraruminal bacterial inoculation, is a viable model to induce LA. Further research is needed to determine the repeatability of this model, and a major application of the model will be in evaluations of novel interventions to prevent LA.

Liver abscesses (LA) in feedlots are costly to the beef industry. At harvest, LA cause an increase in liver condemnations, carcass trimming, and a decrease in quality grade. The objective of this research was to develop an experimental LA model in Holstein steers using an acidotic diet with and without intraruminal inoculation of bacteria involved in LA formation. These data suggest acidotic diet challenges in conjunction with bacterial inoculation were able to induce LA in Holstein steers. The acidotic diet alone caused reduced rumen content pH and caused rumen wall inflammation and damage, observed at harvest. Nonetheless, the addition of bacteria had a compounding effect on rumen damage. Both bacteria inoculated were isolated from 57% of LA suggesting they may work in synergy to form LA.

Short communication: evaluation of an endotoxin challenge and intraruminal bacterial inoculation model to induce liver abscesses in Holstein steers.

Holstein steers (n = 40; initial body weight [BW] = 96.0 ± 10.5 kg) were individually housed in a climate-controlled barn to evaluate potential models for the genesis of liver abscesses (LA). In this 2 × 2 factorial, steers were balanced by BW and randomly assigned to one of two treatments: 1) intravenous saline injection followed by intraruminal bacterial inoculation with Fusobacterium necrophorum subsp. necrophorum (1 × 109 colony forming unit [CFU]/mL) and Salmonella enterica serovar Lubbock (1 × 106 CFU/mL; CON; n = 20 steers); or 2) intravenous injection with 0.25 µg/kg BW of lipopolysaccharide (LPS; Escherichia coli O111:B4) followed by intraruminal bacterial inoculation of F. necrophorum subsp. necrophorum (1 × 109 CFU/mL) and S. enterica serovar Lubbock (1 × 106 CFU/mL; LBI; n = 20 steers) and 1 of 2 harvest dates (3 or 10 d post LPS infusion). Body weights were recorded on days -4, -1, 3, and 10, and blood was collected for hematology on days -4, 3, and 10, relative to LPS infusion on day 0. Intraruminal bacterial inoculation occurred on day 1. Steers from each treatment group were harvested at two different time points on day 3 or 10 to perform gross pathological examination of the lung, rumen, liver, LA (if present), and colon. Feed disappearance was less for LBI than CON (P < 0.01); however, BW did not differ (P = 0.33) between treatments. Neither treatment nor time differed for hematology (P ≥ 0.13), and no gross pathological differences were noted in the lung, liver, LA, or colon (P ≥ 0.25). A treatment × harvest date interaction was noted for ruminal pathology in which LBI had an increased percentage of abnormal rumen scores on day 3 (P < 0.01). These results suggest that an LPS challenge in combination with intraruminal bacterial inoculation of pathogens commonly isolated from LA was not sufficient to induce LA in steers within 3 or 10 d (P = 0.95) when compared to CON. Further evaluation is needed to produce a viable model to investigate the genesis and prevention of LA in cattle.

Liver abscesses in feedlot cattle can cause a decrease in feed intake, average daily gain, feed efficiency, and hot carcass weight. At harvest, liver abscesses result in liver condemnations, carcass trimming, and a potential decrease in quality grade, with an estimated economic cost to packers of $41.6 million annually. Our objective was to evaluate an intravenous endotoxin challenge followed by intraruminal inoculation of bacteria commonly isolated from liver abscesses over a 10-d period as a potential model to understand the genesis and etiology of liver abscesses in cattle and evaluate possible preventative interventions. Results suggest that an endotoxin challenge in combination with intraruminal bacterial inoculation is not a viable model to induce liver abscesses in steers, and bacterial inoculation alone was insufficient to induce liver abscesses. The length of time necessary to induce liver abscesses is also unknown. Based on our results, more research is needed to develop a noninvasive model to induce liver abscesses in cattle.

Non-Antimicrobial Methods to Control Liver Abscesses.

Beef feedlots have few non-microbial approaches available to decrease the incidence of liver abscesses. Decreasing the degree of grain processing might be useful, but methods that decrease dietary starch (eg, feeding digestible fiber sources such as distillers grains) have limited effects. Managing feed intake to decrease daily variation has little effect on abscesses, as do feed additives such as essential oils and tannins. Live yeast and yeast fermentation products provide some benefits, but further research is needed. Lack of reproducible in vitro and in vivo models for rapid screening of potential non-antimicrobial methods has limited progress.

Investigation of tylosin in feed of feedlot cattle and effects on liver abscess prevalence, and fecal and soil microbiomes and resistomes1.

Liver abscesses in feedlot cattle are detrimental to animal performance and economic return. Tylosin, a macrolide antibiotic, is used to reduce prevalence of liver abscesses, though there is variable efficacy among different groups of cattle. There is an increased importance in better understanding the etiology and pathogenesis of this condition because of growing concern over antibiotic resistance and increased scrutiny regarding use of antibiotics in food animal production. The objective of this study was to compare the microbiomes and antimicrobial resistance genes (resistomes) of feces of feedlot cattle administered or not administered tylosin and in their pen soil in 3 geographical regions with differing liver abscess prevalences. Cattle (total of 2,256) from 3 geographical regions were selected for inclusion based on dietary supplementation with tylosin (yes/no). Feces and pen soil samples were collected before harvest, and liver abscesses were identified at harvest. Shotgun and 16S rRNA amplicon sequencing were used to evaluate the soil and feces. Microbiome and resistome composition of feces (as compared by UniFrac distances and Euclidian distances, respectively) did not differ (P > 0.05) among tylosin or no tylosin-administered cattle. However, feedlot location was associated with differences (P ≤ 0.05) of resistomes and microbiomes. Using LASSO, a statistical model identified both fecal and soil microbial communities as predictive of liver abscess prevalence in pens. This model explained 75% of the variation in liver abscess prevalence, though a larger sample size would be needed to increase robustness of the model. These data suggest that tylosin exposure does not have a large impact on cattle resistomes or microbiomes, but instead, location of cattle production may be a stronger driver of both the resistome and microbiome composition of feces.

Evaluation of active dried yeast in the diets of feedlot steers. II. Effects on rumen pH and liver health of feedlot steers1.

The objective of this trial was to determine the benefits of supplementing active dried yeast (ADY; 3 × 1010 CFU/d of Saccharomyces cerevisiae) in diets of growing and finishing steers on ruminal pH and liver health, and evaluate the relationship of these variables with performance traits. Growing beef steers (n = 120) were blocked by weight (i.e., heavy and light) and allocated to 1 of 4 pens in an automated feed intake monitoring system. Steers were fed either control (CON; no ADY) or ADY supplemented in 4 sequential diets: grower diet from days 0 to 70, 2 step up diets (STEP1 and STEP2) for 7 d each, and finishing diet from days 85 to 164. Indwelling rumen boli were administered to monitor rumen pH during days 56 to 106 during the dietary transition. An exchange of pen assignment, within block, occurred on day 70 resulting in 4 final treatment (TRT) assignments: steers fed CON before and after the exchange (CC; n = 30), steers fed CON before and ADY after the exchange (CY; n = 30), steers fed ADY before and CON after the exchange (YC; n = 30), and steers fed ADY (YY; n = 30). Ruminal parameters were analyzed as a randomized complete block design with repeated measures of day, diet and TRT as fixed effects, and block as random effects, using 2 approaches: preliminary analysis of the means or drift analysis (DA; units change from basal values over time). Ruminal pH duration (DUR) below 6.0 (P = 0.05) and 5.8 (P = 0.05) was greater for CY steers than CC steers. Acidosis bout prevalence (pH < 5.6 for 180 consecutive minutes; P < 0.01) and bout DUR (P = 0.05) were greater for CY than other TRT groups. The DA indicated that the ruminal pH variables range, variance, and amplitude of steers in the YC group drifted further from basal pH values than CY and YY steers during the dietary transition (P ≤ 0.02), indicating that removing ADY during the dietary transition was not favorable, but including ADY may reduce ruminal fluctuation. Steers with fewer days experiencing bouts (DEB) had numerically greater ADG (P = 0.11) and tended to have greater G:F (P = 0.06). Liver abscess severity negatively affected ADG (P = 0.04). However, liver abscess severity was not affected by DEB (P = 0.90). There is evidence to suggest that the addition of the specific ADY strain in the diets of beef cattle during the dietary transition may aid in ruminal stabilization, but our study did not find evidence that acidosis bouts were related to abscess prevalence or severity.

Effect of alpha-tocopherol acetate and ascorbic acid on performance, carcass traits, and incidence and severity of liver abscesses in feedlot cattle.

Liver abscesses (LA) in cattle negatively affect feedlot performance by decreasing ADG, feed intake, and G:F ratio. Abscessed livers are condemned and abdominal adhesions associated with LA can result in extensive carcass trimming during harvest, further compounding adverse economic impact. Given regulatory changes pertaining to the use of in-feed antibiotics in cattle production, there is growing interest in alternatives to antibiotics for LA control. The objective of this study was to evaluate the use of antioxidants, crystalline ascorbate (AOX), and alpha-tocopherol acetate, for mitigation of LA in feedlot cattle. Yearling crossbred heifers (n = 392; initial BW 481 ± 9.4 kg) were blocked by previous treatment and allocated randomly to 24 dirt-surfaced feedlot pens (10 m × 35 m) with 14 heifers/pen. Heifers were weighed, implanted with Component TE-200 implants, and placed into feeding pens. Finishing diets consisted of 60% steam-flaked corn, 30% wet corn gluten feed, 8% alfalfa, and 2% supplement (DM basis) that provided 300 mg/d monensin, and either 200 IU/d alpha-tocopherol acetate (CTL) or 2,000 IU/d alpha-tocopherol acetate plus 500 mg/d crystalline AOX. Heifers were fed once daily ad libitum for 94 d, then weighed and transported 450 km to a commercial abattoir for harvest. Hot carcass weight and incidence/severity of LA were determined the day of harvest, and carcass traits were evaluated following 36 h of refrigeration. Compared to CTL, feeding AOX tended to decrease DMI (10.66 vs. 10.31 kg/d; P = 0.08) and improve G:F (0.1204 vs. 0.1254; P = 0.12), but did not impact ADG, incidence of LA (25.6 vs. 23.5% for CTL and AOX, respectively), HCW (828.4 vs. 830.5 kg for CTL and AOX, respectively), or other carcass traits (P > 0.20). In conclusion, feeding antioxidants are not a viable alternative to decrease incidence of LA in finishing cattle.

Effects of intermittent feeding of tylosin phosphate during the finishing period on feedlot performance, carcass characteristics, antimicrobial resistance, and incidence and severity of liver abscesses in steers.

Liver abscesses (LA) are a source of economic loss for feedlot cattle feedlots, and the 2017 veterinary feed directive has restricted further use of tylosin phosphate to prevention and control of LA. Our objective was to evaluate effects of intermittent tylosin phosphate feeding on incidence and severity of LA in feedlot cattle and presence of total antimicrobial-resistant Enterococcus spp. Steers (n = 312, 411.4 ± 6.71 kg) were blocked by initial BW and randomly assigned to a treatment group. Treatments included a negative control group (no tylosin phosphate throughout the finishing period), a positive control group (tylosin phosphate fed continuously throughout the finishing period), and a group that received tylosin phosphate off-label by feeding the drug on a repeated intermittent basis (1 wk on, 2 wk off). Steers were housed in 24 soil-surfaced pens with 13 steers per pen. Body weights of cattle were obtained every 28 d and at the end of 119 d the steers were weighed and harvested at a commercial abattoir. Fecal samples were collected on days 0, 21, and 118 to characterize antimicrobial-resistant Enterococcus spp. Total LA percentage was greater (P = 0.012) for the no tylosin phosphate treatment compared with the other treatments, but did not differ between the continuous tylosin phosphate treatment and the intermittently fed tylosin phosphate treatment (P = 0.716). No difference was observed among treatments for ADG (P = 0.21), DMI (P = 0.28), or G:F (P = 0.75). Marbling score was lower (P = 0.022) for tylosin phosphate treatment when compared with both intermittent treatment and continuous tylosin phosphate treatment. Enterococcus spp. bacterial counts did not differ by treatment group over time (P > 0.05); however, there was a strong period effect for macrolide resistance among all groups (P < 0.01), suggesting an important environmental component as cattle were first placed in pens and then progressed through the feeding period. We conclude that feeding tylosin phosphate intermittently during the finishing phase decreases the total percentage of LA and maintains feedlot performance and carcass characteristics to the same extent as feeding tylosin phosphate throughout the finishing phase; furthermore, we hypothesize that enteric antimicrobial resistance is a result of longer term antibiotic usage in a particular environment rather than a direct short-term result of the treatment during any given feeding period.

Rapid Communication: 16S ribosomal ribonucleic acid characterization of liver abscesses in feedlot cattle from three states in the United States.

Liver abscesses are a major economic burden to beef producers. Although a few causative organisms have been cultured from purulent material, the full polymicrobial diversity of liver abscesses has not been reported. The objective of this study was to characterize purulent material collected from liver abscess in beef cattle produced in different production systems in 3 cattle producing states in the United States using 16S rRNA gene sequencing. Differences between purulent material microbial communities among geographic region of feeding and application of a common antimicrobial were also investigated. Cattle included in the study were fed in California (dairy type) and Colorado and Texas (both beef type). Liver abscesses from a cross section of feedlots, geographic areas, and tylosin phosphate-administered groups were collected at harvest; DNA from 34 liver abscess samples was extracted; and the V4 region of the 16S rRNA gene was amplified and sequenced. Sequences were classified into 5 phyla, 13 classes, and 17 orders in the domain Bacteria. The phyla identified included Bacteroidetes (35.2% of reads), Proteobacteria (28.6%), Fusobacteria (18.2%), Firmicutes (12.4%), and Actinobacteria (5.5%). Sequences matching the genera and , which have previously been identified as causative agents in liver abscesses, were both present in the abscess bacterial communities at a relative abundance of 15.1 and 3.2%, respectively, of the overall relative abundance. Furthermore, 3 of the most common phyla were Gram-negative bacteria. An analysis-of-similarities test was conducted on Euclidean distances to assess differences between cattle treated and not treated with tylosin as well as to assess differences between geographic regions. Geographical region and treatment with tylosin did affect the microbiome ( = 0.002 and = 0.026 respectively); however, a more robust sample scheme is needed to explore these differences. To our knowledge, this is the first publication describing the complex community of liver purulent material using next generation sequencing in cattle. These data provide a framework for research on a more targeted approach to liver abscess prevention and treatment.

Evaluation of infectious complications following percutaneous liver ablation in patients with bilioenteric anastomoses.

PURPOSE: Prior bilioenteric anastomosis (BEA) has been associated with elevated risk of abscess formation after thermal ablation of hepatic tumors. We assessed the incidence of hepatic abscess after thermal ablation in a BEA cohort treated with extended antibiotic regimens following ablation. MATERIALS AND METHODS: Retrospective review was performed to identify patients with BEA who underwent percutaneous hepatic thermal ablation between January 1, 2003-September 1, 2016. Fifteen patients with BEA underwent 18 percutaneous thermal ablation procedures. Patient and procedural characteristics were reviewed, as well as the antibiotic regiment utilized post ablation. Complications were characterized via standardized nomenclature [Common Terminology for Clinically Adverse Events (CTCAE) v4.03]. RESULTS: Fifteen patients with BEA underwent treatment of 49 liver lesions during 18 ablation sessions. Mean follow-up in these patients was 39 months (range 3-138 months). Two patients (11%) developed hepatic abscesses, both of which occurred within 45 days of the ablation procedure while the patients were still on extended prophylactic antibiotic therapy. No additional CTCAE clinically significant complications were observed. CONCLUSION: Thermal ablation of hepatic tumors can be accomplished safely in patients with BEA. Long-term post-procedural antibiotics may mitigate the risk of hepatic abscess formation. Due to the high number of patients who are deemed surgically unresectable, patients with BEA may have limited alternate treatment modalities and percutaneous hepatic thermal ablative treatments warrant consideration.

Liver abscesses in cattle: A review of incidence in Holsteins and of bacteriology and vaccine approaches to control in feedlot cattle.

Liver abscesses are the primary liver abnormality of feedlot cattle at slaughter. The incidence of liver abscesses is highly variable, but generally ranges from 10% to 20%. The incidence of total and the proportion of severely abscessed livers (A+) are greater in Holsteins fed for beef production and culled dairy cows than in beef breeds. The reason for the greater incidence of liver abscesses in Holstein steers is not known, but one of the reasons is likely because of increased days on feed. The high prevalence in cull cows is likely because no specific intervention, such as use of tylosin in the feed, is approved for use in dairy cows. Liver abscesses are generally a sequela to ruminal acidosis and rumenitis in cattle fed diets high in readily-fermentable carbohydrates and low in roughages; thus, the term "acidosis-rumenitis-liver abscess complex." Liver abscesses are almost always polymicrobial infections with Gram negative anaerobes constituting the predominant flora. Almost all studies have concluded that , a ruminal bacterium, is the primary causative agent and (formerly ) is the secondary pathogen. A limited number of studies have been done on the bacterial flora of liver abscesses of culled dairy cows and Holstein feedlot steers. A recent study has reported on isolation of from liver abscesses of Holstein cattle. The control of liver abscesses in feedlot cattle has depended on the use of antibiotics, particularly tylosin, in the feed combined with sound nutritional management to minimize occurrence of acidosis and subsequent rumenitis. Although there is no evidence of resistance development in , the future of tylosin use as a feed additive in feedlot cattle is uncertain. Regardless, beginning January 2017, the use of tylosin in feedlot cattle for the prevention of liver abscesses will be under veterinary oversight. Although tylosin is widely used in the feedlot industry, there is considerable interest in evaluating antibiotic alternatives, such as essential oils and vaccines, to control liver abscesses. Because liver abscess is a bacterial infection and the pathogenicity and virulence factors of have been studied widely, there have been considerable interest and efforts to develop an efficacious vaccine. The 2 antigens that have been targeted for vaccine production are leukotoxin and outer membrane proteins of .

Meta-analysis of the effects of laidlomycin propionate, fed alone or in combination with chlortetracycline, compared with monensin sodium, fed alone or in combination with tylosin, on growth performance, health, and carcass outcomes in finishing steers in North America.

The objective of this research was to use data from multiple studies to comprehensively quantify the effects of feeding 1) laidlomycin propionate (LP), alone and/or in combination with chlortetracycline, compared with 2) monensin sodium (MS), alone and/or in combination with tylosin, at commercially approved dosages, on ADG, DMI, feed efficiency (FE), mortality, and carcass characteristics (HCW and liver abscesses). A secondary objective was to explore potential sources of heterogeneity among the comparative effectiveness studies. A systematic review of peer-reviewed literature and industry reports was used to identify studies that included direct comparisons of these treatments in finishing steers in North America. Random-effects meta-analysis models of performance, carcass, and health-related outcomes were fitted with extracted data, consisting of a total of 17 data sets comprising a total of 135 pens and 13,603 steers. Results showed that pens of steers fed LP had increased ADG (live and carcass adjusted), DMI, and HCW compared with those fed monensin ( < 0.05). However, liver abscesses were more common in LP-fed cattle than in MS-fed cattle ( < 0.05), presumably because of differences in the concurrently fed antimicrobials. No significant effects ( > 0.05) were identified for FE or for health-related outcomes (overall and cause-specific mortality). There was a substantial amount of heterogeneity in outcomes among studies, and when pen size and type of production setting were included in mixed-effects meta-regression models, they accounted for only a small proportion of the between-study heterogeneity found in the meta-analysis models. Therefore, caution should be exercised when interpreting summary estimates in the presence of substantial heterogeneity. However, these results provide comprehensive information on the comparative effects of different ionophores across multiple studies and multiple years, states, and production settings. These unique results can enable quantitative and informed decisions by potential end users of these feed additives that are widely used in the U.S. beef industry for reducing the costs of beef production through enhanced cattle performance.

Use of Prophylactic Antibiotics to Prevent Abscess Formation Following Hepatic Ablation in Patients with Prior Enterobiliary Manipulation.

INTRODUCTION: Prior enterobiliary manipulation confers a high risk for liver abscess formation after hepatic ablation. We aimed to determine if prophylactic antibiotics could prevent post-ablation abscess in patients with a history of hepaticojejunostomy. MATERIALS AND METHODS: This single-institution retrospective study identified 262 patients who underwent 307 percutaneous liver ablation sessions between January 2010 and August 2014. Twelve (4.6 %) patients with prior hepaticojejunostomy were included in this analysis. Ten (83> %) had received an aggressive prophylactic antibiotic regimen consisting of levofloxacin, metronidazole, neomycin, and erythromycin base. Two (16.6 %) had received other antibiotic regimens. Clinical, laboratory, and imaging findings were used to identify abscess formation and antibiotic-related side effects. RESULTS: Twelve ablation sessions were performed during the period studied. During a mean follow-up period of 440 days (range, 77-1784 days), post-ablation abscesses had developed in 2 (16.6 %) patients, who both received the alternative antibiotic regimens. None of the 10 patients who received the aggressive prophylactic antibiotic regimen developed liver abscess. One of the 10 patients who received the aggressive prophylactic antibiotic regimen developed grade 2 antibiotic-related diarrhea and arthralgia. CONCLUSION: An aggressive regimen of prophylactic antibiotics may be effective in preventing liver abscess formation after liver ablation in patients with prior hepaticojejunostomy.

Abscesos hepáticos / Hepatic abscesses

No disponible

Prolonged antibiotic prophylaxis in patients with bilioenteric anastomosis undergoing percutaneous radiofrequency ablation.

PURPOSE: To reduce risk of development of a hepatic abscess in patients with preexisting bilioenteric anastomosis (BEA) undergoing radiofrequency (RF) ablation of hepatic tumors by use of prolonged antibiotic prophylaxis over at least 10 days. MATERIALS AND METHODS: Between April 2003 and June 2011, 184 patients underwent 206 percutaneous RF ablation procedures for hepatic malignancies. Eight patients presented with BEA and were treated in 10 sessions at 14 tumor locations. These 8 patients were male and ranged in age from 55-73 years. Median follow-up was 34 months. Antibiotic prophylaxis was given before the intervention (n = 9, piperacillin/tazobactam; n = 1, ciprofloxacin). Oral antibiotic prophylaxis after the intervention was continued with ciprofloxacin for at least 10 days. In four cases, prophylaxis after the intervention was extended with additional antibiotics. RESULTS: A liver abscess occurred 22 days after 1 of 10 RF ablation sessions in patients with preexisting BEA. The patient who developed an abscess presented with a large hepatocellular carcinoma (59 mm × 54 mm) and underwent transarterial chemoembolization 8 days before RF ablation. No hepatic abscess occurred after 196 RF ablation sessions in 176 patients without BEA. CONCLUSIONS: Preexisting BEA is a risk factor for formation of hepatic abscesses after RF ablation. An antibiotic prophylaxis regimen before the intervention and for a prolonged period after the intervention that covers anaerobic bacteria for at least 10 days is presented. Combined therapy of transarterial chemoembolization and RF ablation increases the risk for complications in patients with known BEA.

Moxifloxacin prophylaxis for chemoembolization or embolization in patients with previous biliary interventions: a pilot study.

OBJECTIVE: Abscess formation is a common serious adverse event after intraarterial therapy for hepatic malignancy in patients with colonized bile ducts. The combination of antibiotic prophylaxis and bowel preparation has been used to prevent hepatic abscess. We describe our outcomes with moxifloxacin prophylaxis alone without bowel preparation. CONCLUSION: Ten patients underwent 25 procedures and were followed for a median of 250 days. No abscesses developed. Our results suggest moxifloxacin alone may suffice for prophylaxis.

Cytotoxic effect of amide derivatives of trifluoromethionine against the enteric protozoan parasite Entamoeba histolytica.

Amoebiasis, caused by infection with the enteric protist Entamoeba histolytica, is one of the major parasitic diseases. Although metronidazole and its derivatives are currently employed in therapy, the paucity of effective drugs and potential clinical resistance necessitate the development of a novel drug. Trifluoromethionine (TFM) is a promising lead compound for antiamoebic drugs. To potentiate the antiamoebic effect of TFM, we synthesised various amide derivatives of TFM and evaluated their cytotoxicity. The amide derivatives of TFM were observed to have a superior cytotoxic effect compared with TFM and metronidazole against E. histolytica in vitro. Although TFM showed cytotoxicity following degradation by methionine gamma-lyase, the derivatives were degraded by the enzyme less efficiently compared with TFM. We further demonstrated that a representative derivative was hydrolysed by the amoebic cell lysate to first yield TFM, followed by degradation similar to TFM. Hydrolysis was partially inhibited by protease inhibitors. A single subcutaneous or oral administration of TFM and its amide derivatives also effectively prevented the formation of amoebic liver abscess in a rodent model. These data demonstrate the improved effectiveness of TFM derivatives against E. histolytica infection and elucidate the mechanisms underlining the mode of action of these compounds.

Effect of essential oils, tylosin, and monensin on finishing steer performance, carcass characteristics, liver abscesses, ruminal fermentation, and digestibility.

A feedlot (Exp. 1) experiment was conducted to evaluate the effects of an essential oil mixture (EOM), experimental essential oil mixture (EXP), tylosin, and monensin (MON) on performance, carcass characteristics, and liver abscesses. A metabolism experiment (Exp. 2) was conducted to evaluate the effects of EOM, EXP, and MON on ruminal fermentation and digestibility in finishing steers. In Exp. 1, 468 yearling steers (398 +/- 34 kg initial BW) were used in 50 pens (10 pens/treatment) and received their respective dietary treatments for 115 d. Five dietary treatments were compared in Exp. 1: 1) control, no additives (CON); 2) EOM, 1.0 g/steer daily; 3) EXP, 1.0 g/steer daily; 4) EOM, 1.0 g/steer daily plus tylosin, 90 mg/steer daily (EOM+T); and 5) monensin, 300 mg/steer daily plus tylosin, 90 mg/steer daily (MON+T). Compared with CON, steers fed MON+T had decreased DMI (P < 0.01), and steers fed EOM+T and MON+T had improved G:F (P 0.58). There was a trend (P = 0.09) for a treatment effect on 12th-rib fat thickness, which resulted in a significant increase in calculated yield grade for the EOM+T treatment. No other carcass characteristics were affected by treatment (P >/= 0.10). Prevalence of total liver abscesses was reduced for steers fed tylosin compared with no tylosin (P < 0.05). In Exp. 2, 8 ruminally fistulated steers (399 +/- 49 kg initial BW) were assigned randomly to 1 of 4 treatments in a replicated 4 x 4 Latin square designed experiment. Treatments were 1) CON, 2) EOM, 3) EXP, and 4) MON with feeding rates similar to Exp. 1. There were no differences in DMI, OM intake, and apparent total tract DM or OM digestibilities among treatments (P > 0.30). Feed intake patterns were similar among feed additive treatments (P > 0.13). Total VFA (P = 0.10) and acetate (P = 0.06) concentrations tended to be affected by treatment with EOM numerically greater than CON. Average ruminal pH ranged from 5.59 to 5.72 and did not differ among treatments. Addition of a EOM or monensin to a diet containing tylosin improves G:F, but little difference was observed in metabolism or digestibility.

Empiric antibiotics for transarterial embolization in hepatocellular carcinoma: indicated?

BACKGROUND: Transarterial embolization (TAE) remains a common treatment option in unresectable patients with hepatocellular cancer (HCC); however there are no standard protocols for post procedure care in these patients who often have extensive disease, marginal liver function, and multiple comorbidities. The aim of this study was to examine antibiotics use in HCC undergoing TAE. METHODS: A prospective review of our center's 1109 hepato-pancreatico-biliary patients, from 1/99 to 7/07, was performed to identify all HCC patients. RESULTS: Two hundred one patients with HCC, of whom 59 (29.4%) underwent bland, TAE, or Yttrium-90 therapy. All embolizations were performed by experienced interventional radiologists and were admitted to the surgical oncology service for post-procedure care. There were 46 men and 13 women, with a median age of 61 y. The mean MELD score was 10.9 (8.5-17) with 25 of 59 having <25% liver involvement. The lesion size ranged from 2 to 12 cm with a mean of 4.88 cm; 24 patients (41%) received a single pre-procedural dose of an antibiotic, 7 (12%) a dose of an antibiotic pre- and post-procedurally, and 28 (47%) did not receive any form of antibiotic. The mean length of stay was 1 (0-5) d depending on adjuvant procedures performed during the same hospital admission. No immediate or long term infectious complications were noted, including liver abscess, cholangitis, pneumonia, or sepsis with a median follow up of 28 mo. CONCLUSION: The current practice of pre- or post-procedure antibiotics is variable and no evidence can support giving or not giving antibiotics for hepatic arterial therapy. The uses are not indicated as prophylaxis against hepatic infectious complications in patients undergoing transarterial embolization for the treatment of hepatocellular cancer.

Characterization of Entamoeba histolytica intermediate subunit lectin-specific human monoclonal antibodies generated in transgenic mice expressing human immunoglobulin loci.

Four fully human monoclonal antibodies (MAbs) to Entamoeba histolytica intermediate subunit lectin (Igl) were prepared in XenoMouse mice, which are transgenic mice expressing human immunoglobulin loci. Examination of the reactivities of these MAbs to recombinant Igl1 and Igl2 of E. histolytica showed that XEhI-20 {immunoglobulin G2(kappa) [IgG2(kappa)]} and XEhI-28 [IgG2(kappa)] were specific to Igl1, XEhI-B5 [IgG2(kappa)] was specific to Igl2, and XEhI-H2 [IgM(kappa)] was reactive with both Igls. Gene analyses revealed that the V(H) and V(L) germ lines were VH3-48 and L2 for XEhI-20, VH3-21 and L2 for XEhI-28, VH3-33 and B3 for XEhI-B5, and VH4-4 and A19 for XEhI-H2, respectively. Flow cytometry analyses showed that the epitopes recognized by all of these MAbs were located on the surfaces of living trophozoites. Confocal microscopy demonstrated that most Igl1 and Igl2 proteins were colocalized on the surface and in the cytoplasm, but different localization patterns in intracellular vacuoles were also present. The preincubation of trophozoites with XEhI-20, XEhI-B5, and XEhI-H2 caused significant inhibition of the adherence of trophozoites to Chinese hamster ovary cells, whereas preincubation with XEhI-28 did not do so. XEhI-20, XEhI-B5, and XEhI-H2 were injected intraperitoneally into hamsters 24 h prior to intrahepatic challenge with E. histolytica trophozoites. One week later, the mean abscess size in groups injected with one of the three MAbs was significantly smaller than that in controls injected with polyclonal IgG or IgM isolated from healthy humans. These results demonstrate that human MAbs to Igls may be applicable for immunoprophylaxis of amebiasis.

Effects of dietary sunflower seeds and tylosin phosphate on production variables, carcass characteristics, fatty acid composition, and liver abscess incidence in crossbred steers.

A 2 x 2 factorial experiment with 48 crossbred steers (with Hereford, Angus, and Charolais genetics, and an initial BW of 373 +/- 8.4 kg) was conducted to evaluate the effects of dietary sunflower seeds (SS) and tylosin phosphate (TP) on production factors, carcass characteristics, liver abscess incidence, and fatty acid composition of the muscle (pars costalis diaphragmatis; PCD) and subcutaneous fat. Individually penned steers were fed either a control diet of 84.5% rolled barley, 14% barley silage, and 1.5% mineral and vitamin mix on a DM basis, or an SS diet, in which SS replaced 15% of the diet. Half the animals fed each diet received TP at 11 mg/kg of DM as a top dressing. Interactions were significant for all production factors. A reduction (P = 0.008) in DMI was observed from 10.1 +/- 0.4 kg/d, in steers fed the control diet, to 8.9 +/- 0.3 and 8.6 +/- 0.3 kg/d, in steers fed the SS and SS + TP diets, respectively. Greater (P = 0.014) ADG was observed for steers fed the control diet than for those fed the SS or SS + TP diet (1.4 vs. 1.1 and 1.2, SE = 0.1 kg/d, respectively); however, G:F ratios were greater (P = 0.011) in steers fed the control diets than in those fed the SS diets. Steers fed the control and SS diets had the heaviest and lightest HCW (347 +/- 6.9 vs. 325 +/- 8.4 kg; P = 0.025), respectively. Lean meat yield (%) of steers fed SS was greater (P = 0.117) than in steers fed the control diets, whereas total lean yield [(HCW x lean meat yield)/100] was similar (P = 0.755). Provision of the SS or SS + TP diet eliminated (P = 0.08 for interaction) liver abscesses compared with the 36 and 9% incidence in steers fed the control or control + TP diet, respectively. Fatty acid weight percentages (wt%) followed similar patterns in PCD and subcutaneous fat. Feeding the SS diets led to greater (P = 0.001) wt% of 18:0 and 18:2n-6, but reduced the wt% of 16:0, 9-cis (c)-18:1, and 18:3n-3 in PCD compared with that in steers fed the control diets, but the wt% of 9c,11-trans (t), and 10t,12c CLA were increased (P = 0.001) by 36 and 400% in PCD. Dietary SS increased (P < 0.001) the wt% of trans-18:1 isomers. The 10t-18:1 and 11t-18:1 isomers were the greatest, but dietary TP elevated (P = 0.004) only 10t-18:1, and total trans-18:1 (excluding 11t-18:1) was 0.47 +/- 0.06 g/100 g of PCD. Dietary SS for finishing steers reduced the incidence of liver abscesses without affecting total lean yield of the carcass, with modest increases in trans fatty acids and in potentially beneficial fatty acids (11t-18:1 and CLA).