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Peter Collignon

Publications and source records attributed to Peter Collignon.

15 recordsLinked to original sources

Human health hazard from antimicrobial-resistant enterococci in animals and food.

The use of antimicrobial agents in the modern farm industry has created a reservoir of resistant bacteria in food animals. Foods of animal origin are often contaminated with enterococci that are likely to contribute resistance genes, virulence factors, or other properties to enterococci IN humans. The potential hazard to human health from antimicrobial-resistant enterococci in animals is questioned by some scientists because of evidence of host specificity of enterococci. Similarly, the occurrences of specific nosocomial clones of enterococci in hospitals have lead to the misconception that antimicrobial-resistant animal enterococci should be disregarded as a human health hazard. On the basis of review of the literature, we find that neither the results provided by molecular typing that classify enterococci as host-specific organisms nor the occurrence of specific nosocomial clones of enterococci provide reasons to change the current view that antimicrobial-resistant enterococci from animals pose a threat to human health. On the contrary, antimicrobial resistance genes appear to spread freely between enterococci from different reservoirs, irrespective of their apparent host association.

Adaptation, Physiological↗

Methicillin-resistant Staphylococcus aureus in the Australian community: an evolving epidemic.

OBJECTIVE: To describe antimicrobial resistance and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolated in community settings in Australia. DESIGN AND SETTING: Survey of S. aureus isolates collected prospectively Australia-wide between July 2004 and February 2005; results were compared with those of similar surveys conducted in 2000 and 2002. MAIN OUTCOME MEASURES: Up to 100 consecutive, unique clinical isolates of S. aureus from outpatient settings were collected at each of 22 teaching hospital and five private laboratories from cities in all Australian states and territories. They were characterised by antimicrobial susceptibilities (by agar dilution methods), coagulase gene typing, pulsed-field gel electrophoresis, multilocus sequence typing, SCCmec typing and polymerase chain reaction tests for Panton-Valentine leukocidin (PVL) gene. RESULTS: 2652 S. aureus isolates were collected, of which 395 (14.9%) were MRSA. The number of community-associated MRSA (CA-MRSA) isolates rose from 4.7% (118/2498) of S. aureus isolates in 2000 to 7.3% (194/2652) in 2004 (P = 0.001). Of the three major CA-MRSA strains, WA-1 constituted 45/257 (18%) of MRSA in 2000 and 64/395 (16%) in 2004 (P = 0.89), while the Queensland (QLD) strain increased from 13/257 (5%) to 58/395 (15%) (P = 0.0004), and the south-west Pacific (SWP) strain decreased from 33/257 (13%) to 26/395 (7%) (P = 0.01). PVL genes were detected in 90/195 (46%) of CA-MRSA strains, including 5/64 (8%) of WA-1, 56/58 (97%) of QLD, and 25/26 (96%) of SWP strains. Among health care-associated MRSA strains, all AUS-2 and AUS-3 isolates were multidrug-resistant, and UK EMRSA-15 isolates were resistant to ciprofloxacin and erythromycin (50%) or to ciprofloxacin alone (44%). Almost all (98%) of CA-MRSA strains were non-multiresistant. CONCLUSIONS: Community-onset MRSA continues to spread throughout Australia. The hypervirulence determinant PVL is often found in two of the most common CA-MRSA strains. The rapid changes in prevalence emphasise the importance of ongoing surveillance.

Australia↗

The routine use of antibiotics to promote animal growth does little to benefit protein undernutrition in the developing world.

Some persons argue that the routine addition of antibiotics to animal feed will help alleviate protein undernutrition in developing countries by increasing meat production. In contrast, we estimate that, if all routine antibiotic use in animal feed were ceased, there would be negligible effects in these countries. Poultry and pork production are unlikely to decrease by more than 2%. Average daily protein supply would decrease by no more than 0.1 g per person (or 0.2% of total protein intake). Eliminating the routine use of in-feed antibiotics will improve human and animal health, by reducing the development and spread of antibiotic-resistant bacteria.

Agriculture↗

Cefoxitin resistance as a surrogate marker for the detection of methicillin-resistant Staphylococcus aureus.

OBJECTIVES: To evaluate the usefulness of cefoxitin when used as a surrogate marker for the detection of methicillin resistance. PATIENTS AND METHODS: Eight hundred and seventy-one strains of Staphylococcus aureus, collected from eight tertiary referral centres serving diverse socio-economic populations, were included in the study using NCCLS disc diffusion and the agar dilution methods. RESULTS: Using cefoxitin and NCCLS criteria for disc diffusion, the sensitivity and specificity for recognizing methicillin resistance were both 100%. Similar results were obtained when the strains were tested by the agar dilution method. The cefoxitin MICs for methicillin-susceptible strains were < or = 4 mg/L. CONCLUSIONS: Testing with cefoxitin as a surrogate marker for the detection of methicillin resistance was very accurate with both disc diffusion and agar dilution methods. Such testing clearly distinguished methicillin-resistant strains of S. aureus from methicillin-susceptible strains.

Biomarkers↗

Staphylococcus aureus bacteremia, Australia.

Staphylococcus aureus bacteremia (SAB) is common and increasing worldwide. A retrospective review was undertaken to quantify the number of cases, their place of acquisition, and the proportions caused by methicillin-resistant S. aureus (MRSA) in 17 hospitals in Australia. Of 3,192 episodes, 1,571 (49%) were community onset. MRSA caused 40% of hospital-onset episodes and 12% of community-onset episodes. The median rate of SAB was 1.48/1,000 admissions (range 0.61-3.24; median rate for hospital-onset SAB was 0.7/1,000 and for community onset 0.8/1,000 admissions). Using these rates, we estimate that approximately 6,900 episodes of SAB occur annually in Australia (35/100,000 population). SAB is common, and a substantial proportion of cases may be preventable. The epidemiology is evolving, with >10% of community-onset SAB now caused by MRSA. This is an emerging infectious disease concern and is likely to impact on empiric antimicrobial drug prescribing in suspected cases of SAB.

Anti-Bacterial Agents↗

Laboratory surveillance of invasive pneumococcal disease in Australia, 2003 predicting the future impact of the universal childhood conjugate vaccine program.

A comprehensive invasive pneumococcal disease (IPD) laboratory surveillance program was carried out in Australia in 2003. This program provided data on the prevalence of pneumococcal serotypes and antimicrobial resistance. There were 1,995 isolates tested with 34 per cent (683) from children aged less than five years and 27 per cent (535) from the elderly aged more than 65 years. One thousand eight hundred and sixty were isolates from blood, 79 from CSF and 56 from other sterile sites. In young children, 84 per cent of isolates were a serotype and 92 per cent a serogroup in the 7-valent pneumococcal conjugate vaccine (7vPCV). Of penicillin resistant isolates in children less than five years of age 85 per cent and 98 per cent were a serotype and serogroup in the 7vPCV respectively. When the universal 7vPCV vaccine program in young children is introduced in 2005, a proportion of cases of IPD should also be prevented in young adults (estimated reduction of 54 cases annually) and elderly Australians (an estimated reduction of 110 cases annually) as a result of improved herd immunity. Pneumococcal serotypes with higher rates of penicillin resistance (19F, 14 and 6B) were more prevalent in the elderly than in young children. In contrast, erythromycin resistance was more common in children less than five years of age (24%) compared to the elderly (15%). The predominant serotype with erythromycin resistance in Australia was serotype 14 and thus there is likely to be a major reduction in erythromycin resistance as a result of 7vPCV vaccination. Continued surveillance of pneumococcal serotype distribution and antibiotic susceptibility will be essential in order to identify serotype replacement by non-vaccine serotypes and to monitor the overall impact of current and future vaccine programs on invasive pneumococcal disease in Australia, not only in young children but also in other age groups.

Age Distribution↗

Fluoroquinolone resistance in Campylobacter absent from isolates, Australia.

Fluoroquinolone resistance was detected in 12 of 370 Australian human Campylobacter isolates; 10 of these were travel-associated, and for 2 isolates travel status was unknown. No resistance was found in isolates known to be locally acquired. In Australia, fluoroquinolones have not been licensed for use in food production animals, a policy that may have relevance for countries with fluoroquinolone-resistant Campylobacter.

Australia↗