Irish-1 and Irish-2: UK epidemic meticillin-resistant Staphylococcus aureus strains associated with Northern Ireland.

Since 1998, an increasing number of meticillin-resistant Staphylococcus aureus (MRSA) isolates with one of two characteristic phage patterns have been referred to the authors' laboratory from Northern Ireland. These strains were designated 'Irish-1' and 'Irish-2'. Analysis of 956 submitted isolates classified as Irish-1 or Irish-2 showed that 97% of the former and 95% of the latter were from Northern Ireland.

Emergence, spread, and characterization of phage variants of epidemic methicillin-resistant Staphylococcus aureus 16 in England and Wales.

Epidemic methicillin-resistant Staphylococcus aureus 16 (EMRSA-16) and EMRSA-15 are the two most important and prevalent EMRSA strains found in the United Kingdom and have also been found in a number of European countries and the United States. We describe for the first time the spread of an EMRSA strain (EMRSA-16) from its point of origin in one hospital to the surrounding hospitals and regions over the following 2 years. In the first 18 months after its original appearance, 136 hospitals referred EMRSA-16 isolates for typing, and interhospital and intraregional spread were reported: it was more prevalent in males between 60 and 80 years old and was isolated from sputum and throat more often than EMRSA-15.

Increased serum resistance in Klebsiella pneumoniae strains producing extended-spectrum beta-lactamases.

The aim of this study was to determine whether there is an association between serum resistance, O serotypes, and the production of extended-spectrum beta-lactamases (ESBLs) in Klebsiella pneumoniae. Ninety ESBL-producing and 178 non-ESBL-producing K. pneumoniae isolates gathered in five European countries were O serotyped and tested for sensitivity to the serum's bactericidal effect.

Recommended test panel for differentiation of Klebsiella species on the basis of a trilateral interlaboratory evaluation of 18 biochemical tests.

Klebsiella pneumoniae and Klebsiella oxytoca are the two most frequently encountered Klebsiella species giving rise to infections in humans, but other Klebsiella species can also be found in clinical specimens: Klebsiella ozaenae, Klebsiella rhinoscleromatis, Klebsiella terrigena, Klebsiella planticola, Klebsiella ornithinolytica, and Enterobacter aerogenes (Klebsiella mobilis). However, many of these species are indistinguishable by the conventional methods employed routinely in the clinical microbiological laboratory. Several investigators have suggested various additional tests, but as yet there is no standardized test panel for identifying all Klebsiella species and subspecies.

Impairment of respiratory burst in polymorphonuclear leukocytes by extended-spectrum beta-lactamase-producing strains of Klebsiella pneumoniae.

The ability of extended-spectrum beta-lactamase (ESBL)-producing and non-ESBL-producing Klebsiella pneumoniae strains to induce a respiratory burst in polymorphonuclear leukocytes (PMNLs) was investigated. Ninety ESBL-producing and 178 non-ESBL-producing Klebsiella pneumoniae isolates were serotyped and their ability to induce a respiratory burst in PMNLs tested by monitoring the cells' chemiluminescence (CL) response. The percentage of isolates inducing high levels of CL response (CL>75%) was significantly higher among non-ESBL producers (52%) than among ESBL producers (32.

A new UK strain of epidemic methicillin-resistant Staphylococcus aureus (EMRSA-17) resistant to multiple antibiotics.

An extensive outbreak in a hospital on the south coast of England in 2000, involving a multi-resistant strain of methicillin-resistant Staphylococcus aureus (MRSA) phenotypically similar to a strain periodically seen in several hospitals in that region since 1996, prompted a study to characterize the strain and determine the extent of its spread. Sixty-nine isolates with related phage patterns obtained between 1997 and 2000 from 19 hospitals were selected for study. Of these, 55 isolates had an identical PFGE profile (designated F1), and eight shared five other PFGE profiles (designated F2-F6), which differed from that of F1 by no more than three bands and were considered related.

Reaction difference rule for phage typing of Staphylococcus aureus at 100 times the routine test dilution.

Duplicate phage typing tests of 150 isolates of methicillin-sensitive and -resistant Staphylococcus aureus at 100 times the routine test dilution showed that the existing reaction difference rule remains satisfactory when isolates are tested on the same day; i.e., two or more reactions must differ before isolates should be considered distinct.

Rate of carriage of Serratia marcescens in patients with and without evidence of infection.

The epidemiology of Serratia marcescens is poorly understood. We designed a study to investigate carriage sites of the organism, and possible modes of transmission of infection. Using Sorbitol-MacConkey agar with colistin 200 IU/ml and MacConkey agar with a 10 microg colistin disc we performed cultures from various sites in patients already infected with S.

Identification and characterization of phage variants of a strain of epidemic methicillin-resistant Staphylococcus aureus (EMRSA-15).

EMRSA-15 is one of the most important strains of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) found in the United Kingdom. It was originally characterized by weak lysis with phage 75 and production of enterotoxin C but not urease. Two variant strains of EMRSA-15 which show a broader phage pattern than the progenitor strain have emerged.

Interpretation of band differences to distinguish strains of Serratia marcescens by pulsed-field gel electrophoresis of XbaI DNA digests.

The number of band differences in DNA macrorestriction profiles required to distinguish unrelated strains from an index strain varies in an outbreak with the species and restriction enzyme used. In order to define this difference for epidemiological studies of Serratia marcescens, we produced DNA fingerprints from 57 isolates of the organism using the restriction enzyme XbaI and pulsed-field gel electrophoresis (PFGE). The isolates were selected on the basis of their epidemiology, serotype and phage-typing patterns to include 28 unrelated strains and 29 representatives from 2 distinct outbreaks.

Epidemiology and susceptibility of serratia marcescens in a large general hospital over an 8-year period.

Over the 8 year period 1988-1995, 1367 isolates of Serratia marcescens were isolated from 582 patients on 12 different wards of a large Dublin hospital and were particularly associated with the surgical intensive care unit. The annual incidence was over 200 isolates from 1990 to 1992 but fell to below 100 following the opening in April 1992 of a replacement surgical hospital incorporating a new intensive care unit on the same site. The most common source of S.

Isolation of Acinetobacter spp. including A. baumannii from vegetables: implications for hospital-acquired infections.

A. baumannii is rarely recovered from the skin of patients or healthy European subjects as other genospecies predominate, but it isa significant nosocomial pathogen. The natural reservoir of this organism is therefore uncertain.

Distribution of Acinetobacter species on skin of healthy humans.

The distribution of the 19 currently known genospecies of Acinetobacter on human skin, i.e. forehead, forearm and toe webs, was determined.

Antibiotic resistance and putative virulence factors of Serratia marcescens with respect to O and K serotypes.

Serratia marcescens serotypes O6:K14, O8:K14 and O28:K28 are common in the natural environment, but rare in hospitals. Serotypes O14:K14 and O27:K14 predominate among clinical strains, but not in the environment, suggesting that the latter serotypes may be more suited for survival in the clinical setting. Consequently, 469 epidemiologically distinct strains of S.

Different O and K serotype distributions among clinical and environmental strains of Serratia marcescens.

Recent revision of the O serotyping scheme for Serratia marcescens has allowed the definitive serological identification of a collection of 511 epidemiologically distinct strains in terms of both lipopolysaccharide (O) antigens and capsular (K) antigens. High levels of typability were achieved, 88% and 91% respectively, with only 2% failing to type with either method. In most cases, non-typability was due to a lack of antigen, i.

Persistence of Pseudomonas aeruginosa strains in respiratory infection in AIDS patients.

Objectives: To establish the clinical pattern of Pseudomonas aeruginosa respiratory infections in HIV-seropositive patients and to determine whether repeated isolation of the organism represents reinfection or recurrence and to assess whether common source, nosocomial infection occurred.

Design And Methods: Evaluation of the clinical pattern of P. aeruginosa respiratory infections by case note review and epidemiological characterization of P.

Epidemiological typing of klebsiellae with extended-spectrum beta-lactamases from European intensive care units.

Extended-spectrum beta-lactamases (ESBLs) are an increasing cause of resistance to oxyimino-aminothiazolyl cephalosporins, especially in klebsiellae. In a recent survey we detected ESBLs in 220 (23%) of 966 consecutive klebsiellae from 35 intensive care units (ICUs) in southern and western Europe. The present study examined the extent to which this distribution reflected epidemic strain spread, as against the distribution of ESBL genes into unrelated strains.

Re-evaluation of the serotypes of Serratia marcescens and separation into two schemes based on lipopolysaccharide (O) and capsular polysaccharide (K) antigens.

Chemical and serological analysis has revealed that many of the 29 O serotype reference strains of Serratia marcescens contain both neutral and acidic polysaccharides which correspond to LPS O antigens and capsular K antigens, respectively. New O and K antigen typing schemes have therefore been devised, based on the known chemical structures of the surface polysaccharides of the organism. These schemes were designed to allow the specific detection of these antigens on unknown strains using ELISAs.