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A S Rossney

Publications and source records attributed to A S Rossney.

11 recordsLinked to original sources
PubMed2006

Epidemiological typing of MRSA isolates from blood cultures taken in Irish hospitals participating in the European Antimicrobial Resistance Surveillance System (1999-2003).

Between 1999 and 2003, meticillin-resistant Staphylococcus aureus (MRSA) isolates recovered from blood cultures in Irish hospitals that participate in the European Antimicrobial Resistance Surveillance System were investigated by epidemiological typing using antibiogram-resistogram (AR) typing, biotyping, and DNA macrorestriction digestion using SmaI followed by pulsed-field gel electrophoresis (PFGE). PFGE patterns were assigned five-digit pulsed-field type (PFT) numbers, and PFTs of apparently related patterns were abbreviated to two-digit PFT groups (PFGs). AR and PFGE typing results were combined to produce AR-PFG types. Representative isolates of each AR-PFG type recovered in 2002 were typed by multilocus sequence typing and staphylococcal cassette chromosome (SCC) mec analysis. Isolates from 1999 and 2000 were also typed by phage typing. The extent to which epidemiological types of MRSA from blood cultures could be extrapolated to the total MRSA population was investigated by comparing results obtained with isolates from the total MRSA population versus those obtained with blood cultures during three study periods. Over the 5 years from 1999 to 2003, 1,580 blood culture isolates from 1,495 patients were analysed. Typeability and discriminatory indices were as follows: AR typing, 1 and 0.97; phage typing, 0.29 and 0.89; PFGE, 0.99 and 0.95; AR-PFG typing, 1 and 0.95. The most frequently occurring AR-PFG types were 06-01, 07-02, 13-00, and 14-00 and were exhibited by 57, 7, 14, and 12% of isolates, respectively. During the study period, the distribution of AR-PFG type changed markedly, with the prevalence of one type (AR-PFG 06-01) increasing by 880%, from 22% (39/181) in 1999 to 80% (343/430) in 2003. Investigation of whether epidemiological types among blood culture isolates of MRSA were representative of the total MRSA population showed that there was no significant difference in most instances. MLST and SCCmec typing showed that AR-PFG types 06-01, 07-02, 13-00, and 14-00 were ST22-MRSA-IV, ST36-MRSA-II, ST8-MRSA-IID, and ST8-MRSA-IIE, respectively.

Animals↗
PubMed2005

Methicillin-resistant Staphylococcus aureus (MRSA) isolated from animals and veterinary personnel in Ireland.

Reports of methicillin-resistant Staphylococcus aureus (MRSA) in animals have become more frequent in recent years. This paper documents the recovery of MRSA from animals with respiratory, urinary tract or wound infection and from animals subjected to surgical procedures following treatment in one veterinary hospital and 16 private veterinary clinics in different geographical locations throughout Ireland. MRSA was recovered from 25 animals comprising 14 dogs, eight horses, one cat, one rabbit and a seal, and also from 10 attendant veterinary personnel. Clinical susceptibility testing suggested that the 35 isolates fell into two different groups. One group of isolates (Group 1) was resistant to one or more of the following classes of antimicrobials: macrolides, lincosamines, tetracyclines and/or fluoroquinolones. The second group (Group 2) was resistant to macrolides, aminoglycosides, tetracyclines and trimethoprim/sulphamethoxazole and variably resistant to fluoroquinolones, lincosamines and rifampicin. One isolate in Group 2 was susceptible to trimethoprim. Epidemiological typing by antibiogram-resistogram (AR) typing, biotyping and by chromosomal DNA restriction fragment length polymorphism analysis using SmaI digestion followed by pulsed field gel electrophoresis (PFGE), confirmed these two major clusters. PFGE analysis showed that most isolates from non-equine animals were indistinguishable from each other and from the isolates from personnel caring for these animals. MRSA was isolated from eight horses which attended six different veterinary practices before referral to an equine veterinary hospital. Isolates from the eight horses and from their attendant personnel had PFGE patterns that were indistinguishable and were unlike the patterns obtained from the other isolates. Comparison of PFGE patterns of isolates from veterinary sources with patterns from MRSA recovered in human hospitals showed that the most frequently occurring pattern of MRSA from non-equine animals was indistinguishable from the predominant pattern obtained from the most prevalent MRSA strain in the human population in Ireland. However, the patterns of the isolates from horses were unlike any patterns previously reported in Irish studies of human isolates. This study shows that transmission of two strains of MRSA is occurring in veterinary practices in Ireland and that one strain may have arisen from human hospitals. The source of the second strain remains to be determined.

Animal Technicians↗
PubMed2002

Strain variation in the MRSA population over a 10-year period in one Dublin hospital.

Between 1989 and 1998, the number of patients carrying methicillin-resistant Staphylococcus aureus in one Dublin hospital increased fourfold, and the antibiogram-resistogram (AR) type distribution changed. In 1989, the predominant AR types were AR01 and AR02; in 1993, AR14 predominated; and in 1994, AR14 and AR13 were predominant. By 1998, the prevalence of AR13 and AR14 had declined and AR06 and AR07 were observed more frequently. In 1989, 65% of isolates were nontypeable using the International Basic Set of Typing Phages. This percentage increased to 78% in 1998. Total cellular DNA macrorestriction analysis reflected the changing AR type distribution. No vancomycin-intermediate isolates were recovered, but possible heteroresistance was observed in 2.7% of isolates. High-level mupirocin resistance occurred in 4% of isolates, and 32% exhibited low-level resistance.

Bacteriophage Typing↗
PubMed1997

Incidence and detection of multi-drug-resistant enterococci in Dublin hospitals.

In February 1994, an outbreak of vancomycin-resistant Enterococcus faecium (VREM) occurred in the oncology unit of a Dublin hospital. Between February and July 1994, VREM was isolated from 18 patients, one staff member and 14 environmental sites within the unit. The isolates also had high-level aminoglycoside and penicillin resistance. Three pulsed-field gel electrophoresis (PFGE) types were identified, two of them from multiple patients and environmental sites. Plasmid typing allowed subdivision of PFGE types. A retrospective study of enterococci isolated from blood cultures between January 1991 and January 1994 showed that, before the outbreak, fewer than 2% of isolates were vancomycin-resistant but that the incidence of high-level gentamicin resistance had increased from 17% to 60% and ampicillin resistance from 22% to 51%. Among clinically significant non-blood-culture enterococci isolated between September and December 1993, fewer than 1% were vancomycin-resistant, 13% were ampicillin-resistant and 44% highly gentamicin-resistant. None produced beta-lactamase. High-content gentamicin disks (120 micrograms) and low-content vancomycin disks (5 micrograms) allowed simple, reliable detection of resistant enterococci. MICs of vancomycin and teicoplanin determined by agar dilution and E-test agreed well, but values tended to be slightly lower by E-test.

Ampicillin Resistance↗
PubMed1994

Staphylococcus aureus phage typing, antimicrobial susceptibility patterns and patient data correlated using a personal computer: advantages for monitoring the epidemiology of MRSA.

Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA) is an important nosocomial pathogen. A problem encountered in the control of staphylococcal nosocomial infection is the difficulty correlating data available from antimicrobial susceptibility patterns (usually available locally) with phage typing patterns which are generally determined in a reference laboratory. Data problems are exaggerated because many patients have numerous samples taken over long periods of time. This paper describes the use of a database, 'DataEase', on a personal computer to correlate available data with patient demographics and to present the resulting information in whatever format is required. The information might be presented as the phage pattern of each isolate from patients in a particular unit per month or as a combination of the phage types and antimicrobial susceptibility patterns of isolates from a particular unit. The system can be used to generate a list of all isolates for phage typing in a format that allows the phage typing pattern to be recorded directly onto the list worksheet. In addition to providing clinically relevant reports, the system simplifies the collation of epidemiological information, data from which showed that since 1987 the incidence of MRSA has been rising in the group of hospitals served by this laboratory; MRSA of phage type 83A became a problem during 1990 and 1991; the incidence of gentamicin-sensitive phage type non-typable MRSA increased fourfold between 1988 and 1991; and the incidence of gentamicin-resistant MRSA rose sharply in 1992.

Bacteriophage Typing↗
PubMed1994

Antibiogram-resistogram typing scheme for methicillin-resistant Staphylococcus aureus.

An antibiogram-resistogram (AR) typing scheme that can simply and rapidly differentiate methicillin-resistant Staphylococcus aureus (MRSA) isolates has been devised. Susceptibility to antibiotics and chemicals was determined by disk diffusion testing. Three disk diffusion methods and three control S. aureus strains were evaluated. A modified Stokes' technique in which S. aureus ATCC 25923 replaced S. aureus NCTC 6571 as the control organism was chosen. Susceptibility patterns against 18 antibiotics and four chemicals were used to determine AR types. AR subtypes were determined with reference to knowledge of the local MRSA population so that plasmid loss would not result in misclassification. AR typing was compared with phage typing and plasmid profiling and found to be more discriminatory than either of these typing methods. Representative isolates of the most frequently occurring AR patterns were further characterised by investigating enterotoxin production, MICs of gentamicin and amikacin, and restriction endonuclease analysis of plasma DNA, to determine whether apparently different strains could have the same AR pattern and to devise confirmatory tests for any such similar patterns. One pattern was shared by two strains but isolates could be differentiated by susceptibility to minocycline. This typing scheme can be used in the diagnostic laboratory and results may be obtained within 24 h.

Anti-Bacterial Agents↗
PubMed1994

Evaluation of an antibiogram-resistogram typing scheme for methicillin-resistant Staphylococcus aureus.

Between Dec. 1992 and Aug. 1993, the MRSA population in the Federated Dublin Voluntary Hospitals and St James's Hospital group was studied with an antibiogram-resistogram (AR) typing scheme in which AR patterns were determined by testing susceptibility to 22 antibiotics and chemicals by a modified Stokes' disk diffusion technique. The typing scheme divided this MRSA population into 31 AR types but 90% of isolates belonged to seven types. Isolates belonging to the most frequently occurring types (AR types 13 and 14) differed only in their reaction to lincomycin (or clindamycin) and could not be distinguished by phage typing, plasmid profiling or restriction endonuclease analysis. The AR typing scheme showed that the incidence of different AR types varied in different hospitals and changed during the study period. This typing method differentiated a strain of MRSA responsible for a nosocomial outbreak in an intensive care unit from other MRSA isolated in the unit, and has distinguished imported strains from local ones. In one hospital, AR typing showed that, although a major outbreak occurred with one AR type, there was also a series of smaller outbreaks with other AR types. The technique can be performed in the diagnostic laboratory and results were available within 24 h.

Anti-Bacterial Agents↗
PubMed1990

Coagulase testing compared with commercial kits for routinely identifying Staphylococcus aureus.

Five commercial Staphylococcus aureus identification kits--Staphaurex (Wellcome), Staphylase (Oxoid), Staphyslide (bioMèrieux), Biostaph (Medlabs) and Bacto Latex (Difco)--were evaluated for the routine identification of S aureus from primary plates in the routine microbiology laboratory. Comparison was made with two methods of tube coagulase testing and five slide methods for detecting clumping factor (slide coagulase testing). Performances were assessed for two groups of organisms, staphylococcal species alone and a combined staphylococcal and non-staphylococcal species group. The effects of growth on selective media and storage of isolates at room temperature and 4 degrees C were investigated. Selective media cannot be recommended, nor can storage of isolates before testing. Ranked according to efficiency value with the combined staphylococcal and non-staphylococcal species group, the kits and coagulase methods performed as follows (the figures in parentheses are the efficiency values for the staphylococcal group alone): tube coagulase reference method 100% (100%), tube coagulase SJH method 99% (99%), Staphaurex 94% (97%), Staphylase 93% (96%), slide coagulase method No 4 93% (94%), slide coagulase method No 5 93% (93%), Bacto Latex 92% (95%), Staphyslide 92% (95%), and Biostaph 87% (91%). It is concluded that a commercial S aureus identification kit should not replace tube coagulase testing for the routine identification of the organism from primary plates and that, even the kits with the best performances, have little advantage over a good slide coagulase test method.

Bacteriological Techniques↗