Comparison of epidemiologically linked Campylobacter jejuni isolated from human and poultry sources.

Campylobacter jejuni is responsible for most foodborne bacterial infections worldwide including Australia. The aim of this study was to investigate a combination of typing methods in the characterization of C. jejuni isolated from clinical diarrhoeal samples (n = 20) and chicken meat (n = 26) in order to identify the source of infection and rank isolates based on their relative risk to humans. Sequencing of the flaA short variable region demonstrated that 86% of clinical isolates had genotypes that were also found in chicken meat. A polymerase chain reaction binary typing system identified 27 different codes based on the presence or absence of genes that have been reported to be associated with various aspects of C. jejuni pathogenicity, indicating that not all isolates may be of equal risk to human health. The lipooligosaccharide (LOS) of the C. jejuni isolates was classified into six classes (A, B, C, E, F, H) with 10·4% remaining unclassified. The majority (72·7%) of clinical isolates possessed sialylated LOS classes. Sialylated LOS classes were also detected in chicken isolates (80·7%). Antimicrobial tests indicated a low level of resistance, with no phenotypic resistance found to most antibiotics tested. A combination of typing approaches was useful to assign isolates to a source of infection and assess their risk to humans.

Concentration and prevalence of Escherichia coli O157 and Salmonella serotypes in sheep during slaughter at two Australian abattoirs.

OBJECTIVE: This study aimed to determine the presence and concentration of Escherichia coli O157 and Salmonella spp. on fleece, faeces and carcases of sheep during slaughter. PROCEDURE: Faeces, fleece and pre-chill carcase samples were collected from 164 sheep slaughtered at two Australian abattoirs. The presence of E. coli O157 and Salmonella spp. were determined by use of automated immunomagnetic separation (AIMS) with enumeration by use of the 'most probable number' (MPN) method. RESULTS: Escherichia coli O157 was isolated from 5% of faeces, 3% of fleeces and 0.6% of pre-chill carcases. The mean log(10) count of E. coli O157 positive faecal samples was 2.32 MPN/g, but counts on fleeces and carcases were below the countable limit (-1 log(10) MPN/cm(2) ). Salmonella spp. were isolated from 20% of faeces, 13% of fleeces and 1.3% of pre-chill carcases. The mean log(10) count of Salmonella spp. in faeces was 1.43 MPN/g and on fleece was -0.24 MPN/cm(2) , but counts on carcases were below the countable limit (-1 log(10) MPN/cm(2) ). CONCLUSION: The prevalence and concentration of pathogens were low in the sheep tested in this study, indicating a low risk of human infection from products derived from these animals.

Relative prevalence of Salmonella Sofia on broiler chickens pre- and postprocessing in Australia.

A survey was conducted to determine the relative prevalence of Salmonella serovars on whole chicken carcasses before and after processing in 3 Australian poultry abattoirs. Ninety and 180 whole chicken carcasses were tested for Salmonella serovars before and after processing, respectively. Each carcass was subjected to a buffered peptone water rinse according to Australian Standard methodologies and Salmonella prevalence was determined using Australian Standard methodologies. After isolation, Salmonella isolates were serotyped and results were analyzed to determine the relative percentage of each serovar at both processing points. Salmonella Sofia was shown to significantly increase its relative prevalence (P < or = 0.05) after processing and proved to be the dominant serovar accounting for 45/89 (51%) isolations before processing and 51/69 (74%) isolations after processing. The reasons for the increased relative prevalence of Salmonella Sofia are currently unknown and require further investigation but may involve factors related to prevalence and numbers on chickens and the ability of Salmonella Sofia to respond to environmental stressors and attach to surfaces.

Distribution, prevalence and persistence of Cronobacter (Enterobacter sakazakii) in the nonprocessing and processing environments of five milk powder factories.

AIMS: To characterise the occurrence of Cronobacter in milk powder factories. METHODS AND RESULTS: Cronobacter was isolated from 32% of 298 environmental samples from five factories. More isolations occurred in nonprocessing (49%) than processing areas (29%), although the greatest occurrence was in a single milk powder area during shutdown maintenance (81%) and the lowest after reinstatement of production hygiene practices (6%). Clonal analysis using PFGE placed 129 isolates into 49 groups. Most clones (45) were unique to each factory and seven were isolated in both milk powder and other areas of the same factory including tanker bays, evaporator rooms, an employee's shoes and external roofs. Cronobacter was not isolated from raw milk processing areas. Within powder areas, 17 clones occurred at more than one and up to eight locations and six occurred more than once at the same location. Between four and seven clones were in the powder areas at each factory. The most prevalent and persistent clones were isolated from external roofs above spray driers, in air treatment areas and where high foot traffic occurs. CONCLUSIONS: Cronobacter is dispersed widely at milk powder factories. This study suggests that distribution is assisted by movement of air, milk powder and personnel and that new hygiene strategies will be needed to reduce prevalence. SIGNIFICANCE AND IMPACT OF THE STUDY: Knowledge of occurrence is essential for the development of strategies to control dissemination of Cronobacter within factories and reduce risk of entry into powdered milk products.

Dexamethasone facilitates discharge after outpatient anorectal surgery.

UNLABELLED: Corticosteroids can decrease pain and postoperative nausea and vomiting after ambulatory surgery. Therefore, we designed a study to evaluate if the routine use of dexamethasone would facilitate the early recovery process after anorectal surgery. A secondary aim of the study was to determine if dexamethasone would increase the incidence of postoperative wound complications. Eighty adult outpatients undergoing anorectal surgery with a standardized monitored anesthesia care technique were randomly assigned to receive either dexamethasone 4 mg IV or an equal volume of saline before the start of surgery. All patients were premedicated with midazolam 2 mg IV and received ketorolac 30 mg IV as a preemptive analgesic. A propofol infusion, 50 microg. kg(-1). min(-1) IV, was initiated and subsequently titrated to maintain an observer's assessment of alertness/sedation score of 2 or 3 (with 5 = awake/alert to 1 = asleep). Fentanyl 25 microg IV was administered 3-5 min before infiltrating the surgical field with a 30-mL local anesthetic mixture containing 15 mL of lidocaine 1% and 15 mL of bupivacaine 0.25% (with epinephrine 1:200,000 and sodium bicarbonate 3 mL). All patients were fast-tracked directly from the operating room to the step-down recovery area. Even though the incidences of postoperative pain and postoperative nausea and vomiting were small in both treatment groups, the time to "home readiness" was significantly shorter in the dexamethasone group. Importantly, there was no increase in the incidence of wound infections (8% vs 12%) or hematoma formation (3% vs 5%) in the dexamethasone (versus saline) group. We conclude that the administration of dexamethasone, 4 mg IV, shortened the time to home readiness without increasing the incidence of postoperative wound infections in a high-risk outpatient population undergoing anorectal surgery. IMPLICATIONS: A single dose of dexamethasone (4 mg IV) decreased the time to "home readiness" without increasing the incidence of postoperative wound complications in an outpatient population undergoing anorectal surgery.

Acid resistance of enterohaemorrhagic and generic Escherichia coli associated with foodborne disease and meat.

As part of the Australia New Zealand Food Authorities (ANZFA) food standards code, salami manufacturers are required to demonstrate that their process is capable of achieving a 3-log reduction in Escherichia coli. Non-pathogenic E. coli strains with similar or greater acid resistance to enterohaemorrhagic E. coli (EHEC) are needed if industry is to conduct challenge studies to demonstrate compliance with the standard. In the present study, E. coli isolates from sheep and beef carcasses and meat were shown to have wide-ranging acid resistance in broth when preadapted to growth in acidic conditions. Times required for a 3-log reduction in E. coli ranged from less than I day to more than 28 days. Variable acid resistance was observed in both EHEC strains associated with foodborne outbreaks and generic E. coli strains. Generic E. coli strains with the greatest acid resistance were assessed for pathogenicity markers and their survival in fermented meat compared with EHEC strains. It was demonstrated that generic E. coli strains could be used for challenge studies to determine compliance with or validate performance standards designed for the control of EHEC.

Onset/offset characteristics and intubating conditions of rapacuronium: a comparison with rocuronium.

We compared onset and offset of action and tracheal intubating conditions after rapacuronium and rocuronium in 60 patients in a randomized, assessor-blinded study. Following induction of anaesthesia with propofol 2.5 mg kg-1, either rapacuronium 1.5 mg kg-1 (n = 30) or rocuronium 0.6 mg kg-1 (n = 30) was administered to facilitate tracheal intubation. Anaesthesia was maintained with either a propofol infusion (100 micrograms kg-1 min-1) or sevoflurane (1% end-tidal) with 66% nitrous oxide (N2O), n = 15 in each subgroup. Neuromuscular monitoring was performed using an electromyographic (EMG) device (Datex Relaxograph). The lag times (mean 42 (SD 11) s and 44 (16) s), maximum block (99 (2)% and 98 (3)%) and intubating conditions at 60 s (good-to-excellent in 86% and 84% of patients) were similar for rapacuronium and rocuronium, respectively. The onset time of rapacuronium was shorter than rocuronium (87 (20) vs 141 (65) s, P < 0.001), and the degree of block at 60 s was greater (69 (26) vs 50 (27)%, P < 0.05). Twenty-five per cent recovery was shorter with rapacuronium than rocuronium during propofol (15.0 (3.2) vs 39.1 (14.2) min, P < 0.001) and sevoflurane (15.1 (4.2) vs 47.8 (19.0) min, P < 0.001) anaesthesia. We conclude that rapacuronium 1.5 mg kg-1 had a more rapid onset, similar intubating conditions, and shorter recovery times than rocuronium 0.6 mg kg-1.

Spontaneous recovery profile of rapacuronium during desflurane, sevoflurane, or propofol anesthesia for outpatient laparoscopy.

UNLABELLED: We evaluated the spontaneous recovery characteristics of rapacuronium during desflurane-, sevoflurane-, or propofol-based anesthesia in 51 consenting women undergoing laparoscopic tubal ligation procedures. After the induction of the anesthesia with standardized doses of propofol and fentanyl, 1.5 mg/kg IV rapacuronium was administered to facilitate tracheal intubation. Patients were randomized to receive either 1 minimum alveolar anesthetic concentration of desflurane, 1 minimum alveolar concentration of sevoflurane, or 100 microg. kg(-1). min(-1) propofol infusion in combination with 66% nitrous oxide in oxygen for maintenance of anesthesia. Neuromuscular blockade was monitored at the wrist by using electromyography. The degree of maximum blockade and the times for first twitch recovery (T(1)) to 5%, 25%, 50%, 75%, and 90%, as well as the recovery index, were similar in all three anesthetic groups. However, recovery times for the train-of-four ratio to achieve 0.7 and 0.8 were significantly longer with desflurane (44.4 +/- 18.9 and 53.5 +/- 22.4 min) and sevoflurane (44.8 +/- 15.1 and 53.2 +/- 15.8 min) compared with propofol (31.8 +/- 5.3 and 36.5 +/- 6.5 min). Eight patients (16%) required a maintenance dose of 0.5 mg/kg rapacuronium and reversal of rapacuronium residual block occurred in three (6%) patients. We conclude that spontaneous recovery after an intubating dose of 1.5 mg/kg rapacuronium was significantly prolonged by both desflurane and sevoflurane compared with propofol-based anesthesia. Routine monitoring of neuromuscular activity is recommended even when a single bolus dose of rapacuronium is administered during ambulatory anesthesia. IMPLICATIONS: When administered for laparoscopic surgery, the duration of action of an intubating dose of rapacuronium was prolonged 40%-50% by desflurane and sevoflurane, respectively, (versus propofol). Monitoring recovery of neuromuscular blockade produced by rapacuronium is particularly important when desflurane or sevoflurane is administered to ensure that an adequate recovery (train-of-four > or = 0.8) is achieved by the end of anesthesia.

Fast-tracking after immersion lithotripsy: general anesthesia versus monitored anesthesia care.

UNLABELLED: Both monitored anesthesia care (MAC) and general anesthesia (GA) offer advantages over epidural anesthesia for immersion lithotripsy. We compared propofol-based MAC and desflurane-based GA techniques for outpatient lithotripsy. After receiving midazolam 2 mg IV, 100 subjects were randomly assigned to one of two anesthetic treatment groups. In the MAC group, propofol 50-100 microg. kg(-1). min(-1) IV was titrated to maintain an observer's assessment of alertness/sedation score of 2-3 (5 = awake/alert to 1 = asleep). Remifentanil 0.05 microg.kg(-1). min(-1) IV supplemented with 0.125 microg/kg IV boluses, was administered for pain control. In the GA group, anesthesia was induced with propofol 1.5 mg/kg IV and remifentanil 0.125 microg/kg IV and maintained with desflurane (2%-4% inspired) and nitrous oxide (60%). Tachypnea (respiratory rate >20 breaths/min) was treated with remifentanil 0.125 microg/kg IV boluses. In the GA group, droperidol (0.625 mg IV) was administered as a prophylactic antiemetic. Recovery times and postoperative side effects were assessed up to 24 h after the procedure. Compared with MAC, the use of GA reduced the opioid requirement and decreased movements and episodes of desaturation (<90%) during the procedure. Although the GA group took longer to return to an observer's assessment of alertness/sedation score of 5, discharge times were similar in both groups. We conclude that GA can provide better conditions for outpatient immersion lithotripsy than MAC sedation without delaying discharge. IMPLICATIONS: A desflurane-based general anesthetic technique using the cuffed oropharyngeal airway device was found to be a highly acceptable alternative to propofol-based monitored anesthesia care sedation for outpatient immersion lithotripsy.

Growth of Listeria monocytogenes on vacuum-packed cooked meats: effects of pH, aw, nitrite and ascorbate.

Slices of cooked meats were inoculated with Listeria monocytogenes strain Murray B, vacuum-packed and stored at either 0 or 5 degrees C. Decreases in pH (6.9-5.9) and aw (0.993-0.960; adjusted with sodium chloride) of the cooked meats increased the lag time and reduced the growth rate at 5 degrees C. The type of meat (beef, pork, chicken or turkey) had no effect on the growth of the organism after allowance was made for pH. Sodium tripolyphosphate (0.3%) increased growth by increasing the pH of the cooked meat. Sodium nitrite reduced the growth rate and increased the lag time. Three microM of residual undissociated nitrite doubled the time taken for a 3 log increase in numbers of L. monocytogenes. The effectiveness of nitrite was significantly increased by sodium ascorbate (0.042%). In the absence of nitrite, ascorbate had no detectable effect on growth. The extent of growth at 0 degree C was similarly influenced by the interaction of pH, aw, nitrite and ascorbate, and was considerably less than at 5 degrees C. Quadratic equations were developed to describe some of the combined effects of pH, aw and residual nitrite on lag, growth rate and time for a 3 log increase in numbers of L. monocytogenes.