Methicillin-resistant Staphylococcus aureus, Western Australia.

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a notable cause of hospital-acquired infections. A statewide screening and control policy was implemented in Western Australia (WA) after an outbreak of epidemic MRSA in a Perth hospital in 1982. We report on statutory notifications from 1998 to 2002 and review the 20-year period from 1983 to 2002. The rate of reporting of community-associated Western Australia MRSA (WAMRSA) escalated from 1998 to 2002 but may have peaked in 2001. Several outbreaks were halted, but they resulted in an increase in reports as a result of screening. A notable increase in ciprofloxacin resistance during the study period was observed as a result of more United Kingdom epidemic MRSA (EMRSA) -15 and -16. WA has seen a persistently low incidence of multidrug-resistant MRSA because of the screening and decolonization program. Non-multidrug-resistant, community-associated WAMRSA strains have not established in WA hospitals.

Management and outcomes of postoperative endophthalmitis since the endophthalmitis vitrectomy study: the Endophthalmitis Population Study of Western Australia (EPSWA)'s fifth report.

PURPOSE: To examine if changes in the diagnosis and management of postoperative endophthalmitis have occurred since 1995, and to identify factors that might predict final visual outcome. DESIGN: Retrospective, population-based, noncomparative, consecutive case series. PARTICIPANTS: Patients with clinically diagnosed endophthalmitis after cataract surgery and lens-related surgery in Western Australia from 1980 to 2000. METHODS: Endophthalmitis cases were identified using record linkage and cross-referencing with the surgical logbooks of vitreoretinal surgeons before validation by medical record review. MAIN OUTCOME MEASURES: Microbiological data (microorganisms isolated and antibiotic susceptibilities), diagnostic interventions, surgical procedures, therapeutic interventions, and visual acuity (VA). RESULTS: During the 21-year period, 213 episodes of endophthalmitis occurred after cataract surgery. Since 1995, both anterior chamber sampling and vitreous sampling have increased significantly. The overall use of vitrectomy has also increased, but we did not observe a difference according to presenting VA. Intravitreal antibiotic use increased significantly, whereas the use of both subconjunctival and IV antibiotics decreased. In one third of patients, the VA at least 6 months after admission for endophthalmitis was worse than 6/18. This was associated with treatment that did not include the use of oral antibiotics (odds ratio [OR], 3.86; 95% confidence interval [CI], 1.21-12.39; P = 0.02), growth from intraocular samples of organisms other than coagulase-negative staphylococci (OR, 9.84; 95% CI, 2.84-34.09; P<0.001), and a discharge VA worse than 6/18 (OR, 6.10; 95% CI, 1.63-22.89; P = 0.01). CONCLUSIONS: Although we observed noticeable changes in the diagnosis and management of endophthalmitis since 1995, visual outcomes have not improved and remain poor. Our finding that treatment with oral antibiotics may be associated with a better visual outcome warrants further investigation.

Eradication of a large outbreak of a single strain of vanB vancomycin-resistant Enterococcus faecium at a major Australian teaching hospital.

OBJECTIVE: To demonstrate that nosocomial transmission of vancomycin-resistant enterococci (VRE) can be terminated and endemicity prevented despite widespread dissemination of an epidemic strain in a large tertiary-care referral hospital. INTERVENTIONS: Two months after the index case was detected in the intensive care unit, 68 patients became either infected or colonized with an epidemic strain of vanB vancomycin-resistant Enterococcus faecium despite standard infection control procedures. The following additional interventions were then introduced to control the outbreak: (1) formation of a VRE executive group; (2) rapid laboratory identification (30 to 48 hours) using culture and polymerase chain reaction detection of vanA and vanB resistance genes; (3) mass screening of all hospitalized patients with isolation of carriers and cohorting of contacts; (4) environmental screening and increased cleaning; (5) electronic flagging of medical records of contacts; and (6) antibiotic restrictions (third-generation cephalosporins and vancomycin). RESULTS: A total of 19,658 patient and 24,396 environmental swabs were processed between July and December 2001. One hundred sixty-nine patients in 23 wards were colonized with a single strain of vanB vancomycin-resistant E. faecium. Introducing additional control measures rapidly brought the outbreak under control. Hospital-wide screening found 39 previously unidentified colonized patients, with only 7 more nonsegregated patients being detected in the next 2 months. The outbreak was terminated within 3 months at a cost of dollar 2.7 million (Australian dollars). CONCLUSION: Despite widespread dissemination of VRE in a large acute care facility, eradication was achievable by a well-resourced, coordinated, multifaceted approach and was in accordance with good clinical governance.

Antimicrobial resistance in Staphylococcus aureus in Australian teaching hospitals, 1989-1999.

An annual survey of antimicrobial resistance in clinical isolates of Staphylococcus aureus was conducted in 21 Australian teaching hospital microbiology laboratories in eight major cities from 1989 to 1999. A total of 19,000 isolates were tested for susceptibility to 18 antimicrobials, with 3795 being methicillin-resistant (MRSA). Resistance to ciprofloxacin in MRSA increased from 4.9% to 75.9%. The proportion of MRSA resistant to erythromycin decreased significantly (99.0%-88.9%), as did that to trimethoprim (98.4%-82.4%) and to tetracycline (96.5%-80.1%). The proportion of MRSA isolated increased in Sydney, Melbourne, Canberra, Adelaide, Perth, and Darwin, but not in Brisbane. The proportion in Hobart peaked in 1994. MRSA in Perth were predominantly non-multiresistant (nmMRSA) throughout the survey (i.e., resistant to less than three of eight indicator antibiotics) due mainly to local strains that originated in the community. The proportion of nmMRSA increased to modest levels in the other cities. In eastern cities, this was due to the appearance of strains closely related to nmMRSA seen in other countries of the southwestern Pacific.

Screening and electronic labelling of ward contacts of vancomycin-resistant Enterococcus faecium vanB carriers during a single-strain hospital outbreak and after discharge from hospital.

A large single-strain outbreak of vancomycin-resistant Enterococcus faecium (VREF) vanB occurred in Royal Perth Hospital from July to December 2001. When a VREF-carrying patient was discovered on a ward, all patients on the ward were screened with rectal swabs. A total of 172 patients were colonised, four with infections, but no deaths were attributable to VREF. The number of rectal swabs required to detect each carrier was recorded. On average four rectal swabs, each collected on separate days, were needed to detect more than 90 per cent of the 172 VREF carriers who were epidemiologically linked to the Royal Perth Hospital outbreak. An electronic alert system (Micro-Alert) was used to identify ward contacts of VREF carriers and enabled those who had not been screened before discharge to be followed-up and screened. Ninety-six contacts were actively followed-up in October 2001 and 32 (33.3%) were found to be VREF carriers. From 28 September 2001 to 30 April 2002, a total of 1,977 ward contacts were screened after discharge from hospital and 54 (2.73%) were found to be carrying VREF. We conclude that during single-strain outbreaks of vancomycin-resistant enterococci in hospitals, patient contacts need to be screened on more than three occasions in order to detect most of the carriers and control the outbreak. Secondly, electronic labelling and active follow-up of ward contacts of VREF carriers resulted in a significant number of carriers being detected who otherwise posed a risk of initiating further outbreaks in hospitals if they were readmitted.

A review of the Royal Perth Hospital Bali experience: an infection control perspective.

Thirty five patients were transferred to Royal Perth Hospital (RPH) after the Bali bombings. The patients had severe burn injuries and were considered to be at high-risk of both the carriage and acquisition of multi-resistant organisms (MROs). Whilst seeking to protect the Bali patients with a comprehensive infection control response, we also sought to protect other high-risk patients from nosocomial acquisition of MROs. MROs were detected from 25 (82%) of the 29 Bali patients admitted to RPH. Bali patients were colonised, or infected, with one or more of the following MROs: multi-resistant Acinetobacter baumannii (MRAB) (19 patients), extended-spectrum ß-lactamase (ESBL) producing Gram-negative bacteria (15 patients), vancomycin-resistant enterococci (VRE) (nine patients), multi-resistant Pseudomonas aeruginosa (MRPA) (six patients), multi-resistant Chryseobacterium sp. (four patients), and methicillin-resistant Staphylococcus aureus (MRSA) (three patients). Five Bali patients developed a total of eight bacteraemic episodes, with MRPA sepsis contributing to death in two patients. Since the Bali bombings horizontal transmission of Bali MROs has occurred in 41 non-Bali patients in RPH. MRPA has had the greatest clinical impact. Eight non-Bali patients developed a total of 11 bacteraemic episodes, with MRPA sepsis contributing to death in four patients. However, apart from MRPA, we have now controlled transmission of the other MROs in RPH. The emergency response to the Bali disaster required strong leadership, good communication and multi-disciplinary teamwork. The infection control strategy contributed to good outcomes for most Bali bombing patients. However, many patients within the Bali cohort were heavily colonised with MROs, and some developed invasive infection. Subsequent nosocomial transmission of these MROs to non-Bali patients has been a legacy of the Bali tragedy.

Dissemination of new methicillin-resistant Staphylococcus aureus clones in the community.

Multiple methicillin-resistant Staphylococcus aureus (MRSA) clones carrying type IV staphylococcal cassette chromosome mec were identified in the community-acquired MRSA strains of both the United States and Australia. They multiplied much faster than health-care-associated MRSA and were resistant to fewer non-beta-lactam antibiotics. They seem to have been derived from more diverse S. aureus populations than health-care-associated MRSA strains.

Proteome analysis of highly immunoreactive proteins of Helicobacter pylori.

BACKGROUND: Identification of the immunoreactive proteins of Helicobacter pylori is important for the development of both diagnostic tests and vaccines relating to the organism. Our aim was to determine whether there are significant differences between human IgG and IgA reactivities to individual H. pylori proteins, and whether patterns of immunoreactivity are sustained across different strains of H. pylori. METHOD: The total complement of protein from seven strains of H. pylori was resolved by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Proteins were transferred electrophoretically onto polyvinylene difluoride (PVDF) membranes, which were probed with sera pooled either from H. pylori-infected patients, or noninfected (control) patients. Highly immunoreactive proteins were detected using chromogenic enzyme-antibody conjugates recognising either serum IgG or IgA. These proteins were then characterised by tryptic peptide-mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). RESULTS: Highly immunoreactive proteins were detected which were common to all seven strains, and recognised by both immunoglobulin subclasses. The proteins appear to be localised in five groups. Protein analysis established that these groups encompass multiple isoforms of chaperonin HspB (two subgroups); urease beta-subunit UreB; elongation factor EF-Tu; and flagellin FlaA. The pattern of highly immunoreactive proteins was strongly conserved across the seven strains. CONCLUSION: These results suggest that within a tightly defined region on the H. pylori proteome map there are five groups of proteins that are highly reactive to both IgG and IgA. Our analysis suggests it is unlikely that the highly immunoreactive clusters harbour any significant proteins other than isoforms of HspB, UreB, EF-Tu and FlaA, and that, with the partial exception of FlaA, these clusters are strongly conserved across all seven strains.