Food animals as reservoirs and potential sources of multidrug-resistant diarrheagenic E. coli pathotypes: Focus on intensive pig farming in South Africa

BackgroundDiarrheagenic E. coli (DEC) strains are a major cause of diarrheal diseases in both developed and developing countries. Healthy asymptomatic animals may be reservoirs of zoonotic DEC, which may enter the food chain via the weak points in hygiene practices.AimWe investigated the prevalence of DEC along the pig production continuum from farm-to-fork.MethodsA total of 417 samples were collected from specific points along the pig production system, that is, farm, transport, abattoir and food. E. coli was isolated and enumerated using Colilert. Ten isolates from each Quanti-tray were selected randomly and phenotypically identified using eosin methylene blue agar selective media. Real-time polymerase chain reaction (PCR) was used to confirm the species and to classify them into the various diarrheagenic pathotypes. Antimicrobial susceptibility was determined against a panel of 20 antibiotics using the Kirby-Bauer disk diffusion method and EUCAST guideline.ResultsThe final sample size consisted of 1044 isolates, of which 45.40% (474/1044) were DEC and 73% (762/1044) were multidrug-resistant. Enteroinvasive E. coli (EIEC) was the most predominant DEC at all the sampling sites.ConclusionThe presence of DEC in food animal production environments and food of animal origin could serve as reservoirs for transmitting these bacteria to humans, especially in occupationally exposed workers and via food. Adherence to good hygienic practices along the pig production continuum is essential for mitigating the risk of transmission and infection, and ensuring food safety.     

Endometrial adenocarcinoma in two young queens

Endometrial adenocarcinoma is described in two young intact female Persian cats presented with haemorrhagic vaginal discharge. The discharge had been present for 3 and 15 days in each case, respectively. On the basis of signalment, history, clinical, laboratory and diagnostic imaging findings a tentative diagnosis of pyometra was made in each cat and ovariohysterectomy was subsequently performed. Histological examination revealed endometrial adenocarcinoma in both cats together with ovarian luteal cysts and pyometra in one case. Immunohistochemistry revealed a diffuse and strongly positive reaction for oestrogen receptors in the nuclei of glandular epithelium in well‐differentiated areas of the neoplastic tissue. Poorly differentiated areas of solid growth pattern had weak and focal expression of oestrogen receptors. Furthermore, the neoplastic cells within these areas displayed moderate to strong diffuse nuclear staining with Ki‐67 antibody suggestive of a high proliferative capacity. The owners reported that the cats were clinically healthy 23 and 21 months after the surgery. These cases highlight the importance of histological examination of surgically resected tissue even when clinical signs and laboratory findings suggest pyometra.     

Extrahepatic cholestasis in the dog and the differentiation of extrahepatic and intrahepatic cholestasis

Summary

The clinical and pathological features of extrahepatic cholestasis in 19 dogs are presented. The condition was most often caused by partial or complete occlusion of the choledochal duct due to neoplastic diseases (12 cases), inflammatory processes (3 cases), or eventration and incarceration of the liver (I case). In only three cases was the condition due to intraluminal obstruction of the choledochal duct.

The anamnestic, laboratory and pathological parameters of these 19 dogs were compared with the findings in 21 dogs with intrahepatic cholestasis. Statistical analysis of these parameters indicated that the presence of acholic faeces, the degree of icterus and the level of plasma γGT where the only parameters of value in the clinical differentation of extrahepatic from intrahepatic cholestasis.

Histological examination of liver biopsies is a simple aid to a confident in vivo diagnosis of extrahepatic cholestasis.     

Effect of genotype and level of supplementary concentrate on foraging activity and vegetation cover in an organic free-range pig system

Abstract

The objectives were to investigate the effects of genotype and level of concentrate on foraging activity and vegetation cover in an organic pasture-based system for growing-finishing pigs. A 44% reduction in the allowance of concentrate more than doubled the rooting activity. The effect of feeding strategy on grazing was less pronounced; this behaviour only tended to be more frequent in the pigs fed restrictedly compared to the pigs fed according to recommendations. There were no significant differences in rooting activity between genotypes; however, the ‘traditional’ genotype grazed significantly more than the ‘modern’ genotype. The vegetation cover declined significantly faster in the paddocks with restrictedly fed pigs than in the paddocks with pigs fed according to recommendations. A restriction in the allowance of concentrate is a valuable tool for stimulating rooting behaviour in integrated systems where the pigs’ rooting behaviour is considered a resource in relation to, for example, soil tillage.     

Antimicrobial susceptibility and serotypes of Actinobacillus (Haemophilus) pleuropneumoniae recovered from Missouri swine

The antimicrobial susceptibility of 73 Actinobacillus (Haemophilus) pleuropneumoniae isolates from swine in Missouri was determined with a microdilution minimal inhibitory concentration test system. Serotyping was accomplished by means of co-agglutination. Serotype 1 (39/73) and serotype 5 (30/73) were commonly found, whereas serotype 7 (4/73) was infrequently encountered. Most isolates (MIC90) were found susceptible to ampicillin (amoxicillin), cephalothin, penicillin, erythromycin, gentamicin, and kanamycin. Marked resistance was found with oxytetracycline, tylosin, and sulfadimethoxine. The data indicate that use of ampicillin (amoxicillin) or penicillin may correlate well with the favorable outcome of treatment.     

Early- and traditionally weaned nursery pigs benefit from phase-feeding pharmacological concentrations of zinc oxide: effect on metallothionein and mineral concentrations.

Benefits of feeding pharmacological concentrations of zinc (Zn) provided by Zn oxide (ZnO) to 21-d conventionally weaned pigs in the nursery have been documented; however, several management questions remain. We conducted two experiments to evaluate the effect on growth from feeding 3,000 ppm Zn as ZnO during different weeks of the nursery period. In Exp. 1 (n = 138, 11.5 d of age, 3.8 kg BW) and Exp. 2 (n = 246, 24.5 d of age, 7.2 kg BW), pigs were fed either basal diets containing 100 ppm supplemental Zn (adequate) or the same diet with an additional 3,000 ppm Zn (high) supplied as ZnO. Pigs were fed four or two dietary phases in Exp. 1 and 2, respectively, that changed in dietary ingredients and nutrient content (lysine and crude protein) to meet the changing physiological needs of the pigs for the 28-d nursery period. Dietary Zn treatments were 1) adequate Zn fed wk 1 to 4, 2) high Zn fed wk 1, 3) high Zn fed wk 2, 4) high Zn fed wk 1 and 2, 5) high Zn fed wk 2 and 3, and 6) high Zn fed wk 1 to 4. In Exp. 1 and 2, pigs fed high Zn for wk 1 and 2 or the entire 28-d nursery period had the greatest (P < .05) ADG. During any week, pigs fed high Zn had greater concentrations of hepatic metallothionein and Zn in plasma, liver, and kidney than those pigs fed adequate Zn (P < .05). In summary, both early- and traditionally weaned pigs need to be fed pharmacological concentrations of Zn provided as ZnO for a minimum of 2 wk immediately after weaning to enhance growth.     

A diagnostic dey for identifying organisms recovered from rotten eggs

A collection of 119 cultures of bacteria was assembled from eggs which had rotted on the premises of producers. All but 13 of the isolates were Gram‐negative. These were characterised in detail and the data used (i) to devise a determinative key that permits rot‐producing bacteria to be identified at generic level, and (it) to establish systems whereby identification at species level can be achieved with the minimum of tests. With the use of these schemes the following were recognised: Pseudomonas fluorescens, Pseudomonas maltophilia, Aeromonas liquefaciens, and members of Flavobacterium, Cytophaga, Proteus, Escherichia, Hafnia and Aerobacter. The literature dealing with the microbiology of rotten eggs was reviewed with the object of assessing the incidence of the organisms listed above in rotten eggs of commercial origin.