Treatment of pigs with enrofloxacin via different oral dosage forms – environmental contaminations and resistance development of Escherichia coli

BackgroundAntibacterial agents play important roles in the treatment of bacterial infections. However, the development of antimicrobial resistance (AMR) and carry-over of substances into the environment are several problems arising during oral treatment of bacterial infections. We assessed AMR development in commensal Escherichia coli (E. coli) in enrofloxacin treated and untreated animals. In addition, we examined fluoroquinolone in the plasma and urine of treated and untreated animals, and in sedimentation dust and aerosol.MethodsIn each trial, six pigs were treated with enrofloxacin via powder, granulate or pellet forms in two time periods (days 1–5 and 22–26). Four pigs served as untreated controls. The minimum inhibitory concentration (MIC) was determined to evaluate AMR development. Analysis of enro- and ciprofloxacin was performed with high performance liquid chromatography.ResultsNon-wildtype E. coli (MIC > 0.125 µg/mL) was detected in the pellet treated group after the first treatment period, whereas in the other groups, non-wildtype isolates were found after the second treatment period. E. coli with MIC > 4 µg/mL was found in only the pellet trial. Untreated animals showed similar susceptibility shifts several days later. Bioavailability differed among the treatment forms (granulate > pellet > powder). Enro- and ciprofloxacin were detected in aerosols and sedimentation dust (granulate, powder > pellet).ConclusionsThis study indicates that the kind of the oral dosage form of antibiotics affects environmental contamination and AMR development in commensal E. coli in treated and untreated pigs.     

Laparoscopic-assisted cystotomy for urolith removal in geldings

OBJECTIVE: To describe a technique for laparoscopic-assisted removal of cystic calculi in geldings and report outcome. STUDY DESIGN: Clinical report. ANIMALS: Four geldings with cystic calculi. METHODS: Laparoscopic-assisted cystotomy and urolith retrieval was performed in 4 anesthetized geldings positioned in dorsal recumbency. With a laparoscope portal located at the umbilicus, the abdomen was insufflated and then the surgical table was tilted (30 degrees head-down position) before an instrumental portal was created parallel and 2-3 cm medial to the left external inguinal ring. Laparoscopic grasping forceps were inserted to grasp the cranial aspect of the bladder and elevate it to the ventral abdominal wall. With the instrumental portal as mid-point, the parainguinal skin incision was longitudinally extended cranial and caudal (approximately 8-10 cm) to accommodate the size of the urolith. The apex of the bladder was exteriorized and sharply incised, the urolith extracted, and after cystotomy closure, the bladder was repositioned. The mini-laparotomy and trocar incisions were closed in layers. RESULTS: There were no intra- or post-operative complications. All horses had minor incisional swelling for 3-4 days. No signs of abdominal or incisional pain were observed. Hematuria and slight stranguria occurred until the 3rd or 4th day. Surgical time (skin incision to skin closure) was 35-40 minutes. On long-term follow-up (up to 12 months) no recurrence of clinical signs associated with cystic calculi occurred. CONCLUSION: Uroliths (6-8 cm diameter) can be removed by laparoscopic-assisted cystotomy in geldings. CLINICAL RELEVANCE: Laparoscopic-assisted cystotomy combines the advantages of the parainguinal laparocystotomy with laparoscopic technique for removal of cystic calculi while avoiding their disadvantages.     

Association study in naturally infected helminth layers shows evidence for influence of interferon-gamma gene variants on Ascaridia galli worm burden

ABSTRACT: Single nucleotide polymorphisms (SNPs) in the genes for interleukin-4, -13 and interferon-gamma, and 21 additional SNPs which previously had been significantly associated with immune traits in the chicken, were genotyped in white and brown layer hens and analyzed for their association with helminth burden following natural infections. A nucleotide substitution located upstream of the promoter of the interferon-gamma gene was significantly associated with the log transformed number of Ascaridia galli in the brown layer line (genotype CC: 6.4 ± 1.0 worms; genotype CT: 11.7 ± 2.2 worms). Therefore, IFNG seems to be a promising candidate gene for further studies on helminth resistance in the chicken.     

Effects of a deficient magnesium supply during the dry period on bone turnover of dairy cows at parturition.

The bone activity and bone mineral content in rib bones resected from 33 dairy cows between 3 and 8 h after parturition were measured, and the effects upon them of a deficient supply of dietary magnesium (Mg) during the last seven weeks of pregnancy were studied. The cows were fed a diet containing either 0.22% magnesium (low Mg) or 0.82% magnesium (high Mg) in the dry matter (DM), and the potassium content of both rations was increased to approximately 4.1% in the DM to reduce the absorption of magnesium. In the cows fed the low-Mg diet a fall in plasma Mg concentration was observed. In the low-Mg, low-parity cows the plasma Mg concentrations at parturition were higher than in the low-Mg, high-parity cows, i.e. 0.83 mmol/l and 0.54 mmol/l, respectively. After parturition four cows in the low-Mg, high-parity group showed clinical signs of hypocalcaemia but none of the other groups did so. The bone formation in low-parity cows was significantly (P less than 0.05) affected by Mg supply, with higher percentages of both trabecular surface covered by osteoid and osteoid volume in the low-Mg group. In the high-parity cows no significant differences in bone formation were found between the low- and high-Mg groups. An inadequate Mg supply resulted in a significantly (P less than 0.05) higher Ca content in the bone ash of low-parity cows and a significantly (P less than 0.05) higher bone ash percentage in the bone of high-parity cows.     

Effects of an inadequate dietary intake of magnesium on osteogenesis in dairy cows during the dry period

The osteogenic activity in the rib bones of 33 dairy cows (14 of parity 1 or 2, and 19 of parity 3 or more) during their last two months of pregnancy, and the effects upon it of a deficient supply of dietary magnesium, were studied by means of intravenous infusions of the fluorochromes oxytetracycline hydrochloride, calcein and chlortetracycline given nine weeks, five weeks and one week, respectively, before the expected time of parturition. Seven weeks before this date the cows' ration was changed to one containing either 0.22 per cent magnesium (LMg) or 0.82 per cent magnesium (HMg) in the dry matter, and the potassium content of both rations was increased to approximately 4.1 per cent in the dry matter to reduce the absorption of magnesium. Four of the 10 LMg-high parity cows showed signs of periparturient hypocalcaemia. A significant decrease in the number of labelled osteons towards parturition was demonstrated in both the low parity (P less than 0.05) and high parity cows (P less than 0.001). The mean bone apposition rate in high parity cows was significantly lower (P less than 0.001) than in low parity cows. The different levels of magnesium in the diets of the cows had no significant effects on the numbers of osteons which were labelled nine weeks, five weeks or one week before parturition, or on the numbers of osteons which took more than one label or on the bone apposition rate. These results show that in these cows the rate of bone remodelling decreased as parturition approached.     

Indications, surgical technique, and long-term experience with laparoscopic closure of the nephrosplenic space in standing horses

OBJECTIVE: To describe surgical technique and outcome after laparoscopic closure of the nephrosplenic space for treatment of recurrent left dorsal displacement of the left colon (LDDLC) in standing horses. STUDY DESIGN: Retrospective study. ANIMALS: Forty-four horses with LDDLC. METHODS: Laparoscopic portals were located in the left flank region. After administration of etilefrin intravenously to contract the spleen, the dorsal splenic margin was sutured to the nephrosplenic ligament to obliterate the nephrosplenic space. Horses were re-examined (< or = 3 years) for history of recurrence. In addition, medical records of 4,852 horses treated for colic over 16 years were evaluated to establish incidence of LDDLC and recurrence after treatment. RESULTS: Splenic contraction facilitated suture placement and closure of the nephrosplenic space was achieved without complications. LDDLC recurrence did not occur although 5 horses had subsequent episodes of colic; 4 horses had displacement of the ascending colon between the spleen and body wall. Review of medical records revealed an incidence of LDDLC of 6% and recurrence of 21% in a population of horses with signs of colic. CONCLUSION: Laparoscopic closure of the nephrosplenic space, facilitated by etilefrin-induced splenic contraction can be efficiently performed in standing horses. CLINICAL RELEVANCE: Laparoscopic ablation of the nephrosplenic space should be considered in horses that are predisposed to recurrent LDDLC.     

Ecotoxicological characterization of sediment cores from the western Baltic Sea (Mecklenburg Bight) using GC–MS and in vitro biotests

Background, aim, and scope

The Mecklenburg Bight (Western Baltic Sea) near Luebeck, Germany was historically used to dump industrial waste at sea and, thus, sediments in some regions are highly polluted at present. While earlier studies identified hot spots of chemical pollution, little is known about biological activities and impacts on exposed marine organisms. This study aimed to assess the pollution in the Mecklenburg Bight to determine the degree of contamination with sediment-bound polycyclic aromatic hydrocarbons (PAHs) as well as biological activities.

Materials and methods

Sediment cores with a depth of 30 cm were sampled at a dumping site and at a reference site, sliced in distinct layers, freeze-dried, and processed using the accelerated solvent extraction method. Sediment was characterized measuring total organic carbon (TOC) and soot contents. Concentrations of the 16 EPA-PAHs were determined with chemical analysis (gas chromatography–mass spectroscopy) in each sediment slice and referred to the determined TOC content. Further on, in vitro biotests were applied to determine toxic effects of contaminants in the sediment. The acute neutral red retention assay indicated no specific cytotoxic effects. Arylhydrocarbon receptor (AhR)-mediated activities were measured using the mechanism-specific 7-ethoxyresorufin-O-deethylase induction assay. Both biotests were performed with rainbow trout (Oncorhynchus mykiss) liver cells (RTL-W1). Analyzed compound concentrations and biological activities were given in toxicological equivalent concentrations (chem- and bio-TEQs) to determine shares of analyzed EPA-PAHs to the overall activity.

Results

TOC and soot contents indicated a significant alteration through the sediment core at the dumping site. EPA-PAH concentrations were referred to TOC and indicated elevated concentrations at the dumping site. Maximum PAH concentrations (14 to 16 cm depth; 5.44 µg/g TOC) were 300-fold increased at the dumping site, compared to the reference site (4 to 6 cm depth; 0.017 µg/g TOC). Cytotoxicity as determined in the neutral red retention assay was elevated in some layers at the dumping site (maximum in 4 to 6 cm depth; NR₅₀?=?14 mg/ml), but not correlated with TOC or soot contents. Ah receptor agonist activities were clearly elevated in highly PAH-loaded layers at both sites. At the dumping site, maximum activities were determined reflected by a bio-TEQ of 223,000 pg/g (19 to 22 cm), in contrast to a bio-TEQ of 41,000 pg/g (6 to 8 cm) at the reference site. Further on, shares of EPA-PAHs to the overall activity were determined and contributed >40% at the dumping site and between 4% and 17% at the reference site. Chem-TEQs were found to exceed bio-TEQs in a depth of 11 to 22 cm, indicating the presence of Ah receptor antagonistic or inhibitive compounds.

Discussion

Sediments from the dumping site were determined to be highly contaminated and caused toxic effects in depths that are known to be influenced by dumping activities. In contrast, the reference sediment indicated only near to surface layers to be minor contaminated. In comparison with highly polluted sediments from other marine sites, the contamination of the dumping site could be ranked as elevated. Chem-TEQs exceeding bio-TEQs in a depth of 11 to 22 cm seem to be caused by AhR antagonistic compounds in the dumped material. Furthermore, particle-bound PAH concentrations assessed in this study were discussed against freely dissolved concentrations in interstitial water, as determined in a different study with the same sediment core.

Conclusions

Sediments in the inner Mecklenburg Bight could be shown to be highly contaminated, at least with PAHs, causing articulate increased Ah receptor-mediated activities. Marine organisms may be exposed to these contaminants, in particular when inhabiting the sediment.

Recommendations and perspectives

Further research activities should extend the range of chemically analyzed pollutants and applied biotests and endpoints. Monitoring should close the gap between analytical methods in the laboratory and the field to determine possible impacts on organisms at site.     

Left- and right-sided laparoscopic-assisted nephrectomy in standing horses with unilateral renal disease

Objective— To describe a technique for, and outcome after, left‐ or right‐sided laparoscopic‐assisted nephrectomy in standing horses with unilateral renal disease. Study Design— Clinical report. Animals— Horses (n=3) with unilateral renal disease. Methods— Horses were sedated with detomidine (0.01 mg/kg intravenously [IV]) and levomethadone (0.05 mg/kg IV). Paravertebral anesthesia and infiltration‐anesthesia with 2% lidocaine were used to create a surgical field incorporating the 17th intercostal space and paralumbar fossa. Two separate, ipsilateral portals and a mini‐laparotomy were used. The perirenal peritoneum was horizontally incised (10–15 cm) using endoscissors and the incision digitally enlarged for manual dissection of the perirenal fat and kidney mobilization. The renal vessels and ureter were individually dissected, ligated, and transected under laparoscopic observation and the kidney removed. The perirenal and laparotomy peritoneal defects were not closed; and the laparotomy was closed in a multilayered fashion. The transverse abdominal muscle was apposed in a continuous pattern using 1 polyglactin 910, the subcutaneous tissue (simple continuous pattern) and skin (simple interrupted pattern) with 2–0 polyglactin 910. Results— Left (2) and right (1) sided laparoscopic‐assisted nephrectomy (1 nephrolithiasis, 2 hydronephrosis) was performed successfully. Sedation and local anesthesia was adequate for intraoperative immobilization and analgesia. No intraoperative complications occurred. Incisional seroma formation and fever occurred on days 3 and 4 in 1 horse and resolved with medical management. Conclusion— Laparoscopic‐assisted nephrectomy can be used for removal of the left or right kidney in standing horses with unilateral kidney disease. Clinical Relevance— To avoid risks associated with general anesthesia and to reduce surgical trauma, laparoscopic‐assisted nephrectomy can be performed in the standing sedated horse using a 2 portal technique and a mini‐laparotomy.