D J Taylor

Trends of antimicrobial resistance in bacterial isolates from a small animal referral hospital

A longitudinal, retrospective investigation was made of antimicrobial resistance in bacterial isolates obtained from clinical cases in a small animal hospital between 1989 and 1997. Isolates of Escherichia coli and Staphylococcus species were used as Gram-negative and Gram-positive indicator organisms, respectively, and the annual prevalence of antimicrobial resistance was calculated for each organism to each of nine (for E coli) and 11 (for Staphylococcus species) appropriate antimicrobials, including enrofloxacin. Using a chi-square test for trend, statistically significant, rising trends were identified in the resistance of E coli to amoxycillin (P=0.04), clavulanate-amoxycillin (P<0.01) and streptomycin (P<0.01), and in the resistance of Staphylococcus species to erythromycin (P<0.01). There was an equivocal, rising trend for the resistance of Staphylococcus species to cephalexin. No significant trends were apparent for any of the other 15 organism/drug interactions. The annual prevalence of multiple drug resistance was calculated for E coli, Proteus species, Pseudomonas species, staphylococci and streptococci, but no statistically significant trends were identified.

Factors Associated with Cross-Contamination of Hides of Scottish Cattle by Escherichia coli O157

ABSTRACT The putative source of hide contamination for 236 cattle in Scotland followed from the farm through to slaughter was determined using phage and verocytotoxin type data. The majority of cattle (84%) were found to have subtypes of Escherichia coli O157 on their hide that had not been found previously in any animal from the farm of origin, strongly suggesting that contamination occurred once animals had left the farm of origin. Using logistic regression analysis, several variables and factors were found to be strongly associated (P < 0.01) with cross-contamination of cattle hides at the univariate level; commercial transport to slaughter, transport with other animals, use of a crush, line automation, and increasing slaughterhouse throughput were all risk factors, while feeding hay in lairage, processing an animal earlier in a slaughter cohort, and cleaning the landing area poststunning were protective. In the multivariable model, with the slaughterhouse and the farm group included as random effects, factors associated with the cross-contamination of cattle hides were identified. Transport to the slaughterhouse by a commercial hauler had a borderline-significant association with increased odds of an animal having a cross-contaminated hide (odds ratio [OR] [95% confidence interval {CI}] = 5.7 [0.99, 33.0]; P = 0.05). At the slaughterhouse, providing hay to cattle waiting in lairage (OR [95% CI] = 0.04 [<0.01, 1.04]; P = 0.05) and cleaning the landing area (OR [95% CI] = 0.03 [<0.01, 1.15,]; P = 0.06) also had a borderline-significant association with decreased odds of an animal having a cross-contaminated hide. Although the prevalence of carcass contamination remains very low, targeted intervention at the preslaughter stage may have the potential to reduce further the risk to public health.

Frozen Storage of Escherichia coli O157 in Buffered Peptone Water and Its Detection on Bovine Carcasses

The adaptation of a standard Escherichia coli O157 isolation method involving immunomagnetic separation and a period of frozen storage was investigated. A series of experiments was designed to test the recovery of a bovine strain of E. coli O157 from buffered peptone water after a period of frozen storage at -80 degrees C. The effects of the addition of glycerol at 5 and 10%, freezing time, the number of freeze-thaw cycles, the method of freezing and the method of thawing, the inclusion of a resuscitation-and-incubation step, and the sensitivity of the isolation method were investigated. The most effective method of storing frozen samples for 6 months and recovering strains of E. coli O157 after storage was found to involve 6 h of incubation of sample material in buffered peptone water at 37 degrees C before frozen storage at -80 degrees C with 10% glycerol, a rapid thaw after frozen storage, and resuscitation at 27 degrees C for 1 h and incubation at 37 degrees C for 1 h to allow freeze-injured and stressed bacteria to recover with a period of growth prior to immunomagnetic separation isolation. There was no significant decrease in log counts of a bovine strain E. coli O157 over 6 months of frozen storage in buffered peptone water with 10% glycerol. With this method, it was possible to isolate E. coli O157 from naturally infected bovine carcasses after a period of frozen storage.

Assessing techniques for disinfecting sites for inserting intravenous catheters into the jugular veins of horses

The sites of insertion of catheters into the jugular veins of six horses were investigated to determine common isolates and to assess the effectiveness of two disinfection protocols with the hair coat left long, clipped or shaved. Skin commensals (Staphylococcus, Streptococcus and Micrococcus species) and environmental contaminants (Bacillus, Enterobacteriaceae, Aspergillus and Mucor species) were the microorganisms most frequently isolated. Chlorhexidine gluconate and povidone-iodine-based skin disinfection protocols resulted in significant reductions in the number of bacterial isolates from clipped sites. With chlorhexidine, there were no significant differences between the reductions observed at sites with the hair coat left long, clipped or shaved.

Isolation of avian strains of Salmonella enterica serovar Typhimurium from cats with enteric disease in the United Kingdom

AVIAN-ADAPTED strains of Salmonella enterica serovar Typhimurium have been detected in wild birds, particularly finches (family Fringillidae), in Europe, Scandinavia and North America ([Daoust and others 2000][1], [Tauni and Osterlund 2000][2], [Pennycott and others 2006][3]). In the uk, these

Salmonella infections in garden birds and cats in a domestic environment.

Wild bird strains of Salmonella enterica serovar Typhimurium, including phage types (definitive types) DT40 and DT56v, have been associated with disease in finches (Family Fringillidae), cats and human beings in the UK and Sweden (Tauni and Osterlund 2000, Pennycott and others 2006, Hughes and others 2008, Philbey and others 2008, 2009). Salmonellosis in wild finches in the UK is related to congregation of birds around feeding tables in gardens in the cooler months of the year (Pennycott and others 2006). Cats are thought to become infected with wild bird strains of S Typhimurium by catching small birds at these feeding stations (Philbey and others 2008), but a direct link between salmonellosis in birds and cats has not been demonstrated. This short communication describes a study to investigate the occurrence of Salmonella species in wild birds, cats and the environment in a domestic setting. The study site comprised a household and two adjoining village gardens in Lennoxtown, near Glasgow, with three human occupants and two male neutered domestic shorthair cats (cat 1: five years old; cat 2: 10 years old). Feeders containing mixed seed, niger seed, peanuts or fat were provided at two feeding sites in each of the gardens. Sick birds were observed in both gardens over an eight-week-period from late December 2008 to early February 2009 (Fig 1a). During this period, …

Serovars, bacteriophage types and antimicrobial sensitivities associated with salmonellosis in dogs in the UK (1954-2012).

Serovars and bacteriophage (phage) types were determined for 442 isolates of Salmonella enterica from dogs in the UK submitted to the Scottish Salmonella Reference Laboratory from 1954 to 2012. The most frequent serovars were Salmonella Typhimurium (196 isolates; 44.3 per cent), Dublin (40 isolates; 9.0 per cent), Enteritidis (28 isolates; 6.3 per cent), Montevideo (19 isolates; 4.3 per cent), Virchow (10 isolates; 2.3 per cent), Heidelberg (8 isolates; 1.8 per cent) and Derby (8 isolates; 1.8 per cent), along with 55 other recognised serovars among 127 other isolates, and six incompletely classified isolates. Serovars were frequently represented by strains commonly associated with poultry, cattle or pigs and their products. Among 196 Salmonella Typhimurium isolates from dogs, the most frequent phage types (definitive types) were the multiple antimicrobial-resistant strains DT104 (62 isolates), DT204c (18 isolates) and DT193 (8 isolates), along with antimicrobial sensitive wild finch strains DT40 (13 isolates) and DT56 variant (8 isolates). Eleven of 28 isolates of Salmonella Enteritidis were phage type 4. S enterica was frequently recovered from faecal or intestinal samples of dogs with diarrhoea, although many dogs had concurrent infection with other enteric pathogens. Salmonella Dublin was recovered from the brain and/or cerebrospinal fluid of two dogs with meningoencephalitis. Salmonella Kedougou was isolated from the joint fluid of a dog with septic arthritis. Salmonella Typhimurium and Salmonella Dublin were each recovered from the vaginas of bitches that had aborted. Isolates of Salmonella Enteritidis phage types 1, 4 and 8, Salmonella Typhimurium DT104, Salmonella Dublin and Salmonella Indiana were isolated from clinically healthy dogs in households where the same strains were recovered from human beings with diarrhoea. The pattern ampicillin-chloramphenicol-spectinomycin-streptomycin-sulfamethoxazole-tetracycline (ACSpSSuT) was the most frequent resistance phenotype and was observed in 44 (13.3 per cent) of 330 isolates. Dogs in the UK are exposed to a wide variety of serovars of S enterica, sometimes associated with clinical disease, and represent a zoonotic risk.

Regional control of sheep scab in UK flocks

BEFORE the deregulation of sheep scab control measures (Sheep Scab [National Dip] Order 1990) in July 1992, the combination of summer and autumn plunge dipping of all sheep for one minute in propetamphos, diazinon or flumethrin solutions, the licensing of markets, and the statutory restriction of movement of sheep out of infected areas maintained the annual incidence of sheep scab in the UK at less than 100 outbreaks per year. Plunge dipping may involve considerable animal handling and can prove expensive; it also raises concerns about operator safety and environmental contamination. Many shepherds and farmers, therefore, no longer annually plunge dip their sheep. Some rely on systemic endectocides for sheep scab control, but nowadays many do not actively prevent the disease in their flocks. The result is that, in areas with dense sheep populations, large numbers of animals are at risk of potentially severe disease. This article argues that the way forward for controlling sheep scab is to adopt a collaborative approach, rather than rely on the efforts of individual farms, which are all too often unsuccessful.

Laryngeal abscessation due to Mannheimia haemolytica in an alpaca (Vicugna pacos) cria

ALPACAS ( Vicugna pacos ) are domesticated members of the New World South American camelid family farmed for their fleece and kept as domestic pets in the uk. Relatively little is known about respiratory disease in alpacas, although they are susceptible to several bacterial, fungal and viral

Fatal mesenteric lymphadenitis in cattle caused by Listeria monocytogenes.

IN ADULT cattle, infection with Listeria monocytogenes is well recognised as a cause of encephalitis and also abortion in the last third of pregnancy ([Ladds and others 1974][1], [Low and Donachie 1997][2]). The organism is widespread in the environment and the risk of listeriosis is increased by