The 'Oxford Staphylococcus': a note of caution.
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Bacterial Toxins↗
Biomedical subjects
Angela M Kearns
Publications and source records attributed to Angela M Kearns.
Cavitatory lung disease complicating empyema in children.
OBJECTIVE: The incidence of empyema has increased dramatically in children in the UK over the last decade. Streptococcus pneumoniae (S. pneumoniae) serotype 1 is the dominant serotype. We have observed more pneumatocoele and bronchopleural fistulae formation over this time. AIM: Our aim was to determine the number of children who developed cavitatory disease as a complication of empyema at a tertiary referral centre and whether there was any association with S. pneumoniae serotype 1. METHOD: We reviewed 75 cases presenting with empyema or parapneumonic effusion between February 1997 and July 2003. Bacterial culture and pneumococcal antigen detection were supplemented by real-time polymerase chain reaction (PCR) to detect pneumococcal DNA. RESULTS: Cavitatory disease was present in 15 cases. Three children developed bronchopleural fistulae. S. pneumoniae was detected in 13 of 15 cases (4 cases serotype 1, 3 serotype 3, 2 serotype 14, and 2 serotype 9V; serotype assay was not performed in two cases). Staphylococcus aureus (S. aureus) was isolated in one case. No organism was isolated in the final case but an Antistreptolysin-O titre was >800 U/ml on two occasions suggestive of group A streptococcal infection. CONCLUSION: Twenty percentage of cases of empyema in our series were complicated by cavitatory lung disease. It is an important complication of childhood empyema associated classically with S. aureus, but these data suggest that S. pneumoniae now appears to be the main cause. There does not seem to be an association with any particular serotype.
Adolescent↗
A virulence-associated gene microarray: a tool for investigation of the evolution and pathogenic potential of Staphylococcus aureus.
An oligonucleotide probe microarray for investigation of the evolution of epidemic Staphylococcus aureus strains has been constructed. The array comprises 383 probes based on virulence-associated genes present in four key strains. Twelve strains including seven for which the complete chromosomal nucleotide sequence was available were tested on the array. Twenty-six per cent of the probes were able to differentiate between strains to give a minimum of two gene differences between pairs. A gene difference distance tree based on the array data had approximately the same topology as one prepared using concatenated MLST sequences. Differences in the topologies of these trees were found to indicate that large-scale recombination events had occurred during the evolution of the species. One such occurrence appears to have been a key event in the genesis of the EMRSA-15 clone (ST22) that currently represents the most prevalent methicillin-resistant S. aureus (MRSA) in the UK.
Bacterial Proteins↗
Rapid detection and quantification of CMV DNA in urine using LightCycler-based real-time PCR.
A real-time quantitative PCR-hybridisation assay was developed for the detection of human cytomegalovirus DNA in clinical material. The assay is based on a LightCycler (LC) and provides both rapid results (<1 h) and quantification over a broad dynamic range (2 x 10(3)-5 x 10(8) CMV DNA copies/ml). Given that the assay showed a 3-fold increase in sensitivity compared to detection of early antigen fluorescent foci (DEAFF) testing of urine samples, we investigated the practicality of testing surveillance such specimens from immunocompromised patients at risk of CMV disease. Over a 12-month period, CMV DNA was detected in 81 (7%) of 1154 urine samples examined. A total of 28 patients tested positive; urine viral loads were higher in 13 infants being investigated for suspected congenital infection (median 1.6 x 10(5) copies/ml) compared with 15 transplant recipients (median 9 x 10(3) copies/ml). Urine samples could be tested directly without processing such that results were available in <1h. Real-time PCR provided information on the quantification of CMV DNA in urine and proved a reliable method for the surveillance of immunocompromised patients at risk of CMV disease. This approach should facilitate a better understanding of the epidemiology and natural history of CMV disease. Moreover, LC-based quantitative PCR is a potentially valuable tool for the management of CMV disease; assisting with the prompt initiation of treatment and assessing therapeutic response.
Cytomegalovirus↗
Rapid real-time PCR for determination of penicillin susceptibility in pneumococcal meningitis, including culture-negative cases.
A novel real-time PCR-hybridization assay was developed for the rapid (<1 h) detection of penicillin susceptibility in Streptococcus pneumoniae. When applied to 24 pneumococcal DNA-positive cerebrospinal fluid extracts, penicillin-sensitive S. pneumoniae was detected in all instances. Real-time PCR proved more sensitive than culture, microscopy, or antigen detection and provided susceptibility data even in culture-negative cases.
Adolescent↗
Re-emergence of early pandemic Staphylococcus aureus as a community-acquired meticillin-resistant clone.
During the 1950s, the notorious penicillin-resistant clone of Staphylococcus aureus known as phage type 80/81 emerged and caused serious hospital-acquired and community-acquired infections worldwide. This clone was largely eliminated in the 1960s, concurrent with the widespread use of penicillinase-resistant beta lactams. We investigated whether early 80/81 isolates had the genes for Panton-Valentine leucocidin, a toxin associated with virulence in healthy young people. Multilocus sequence analysis suggested that descendants of 80/81 have acquired meticillin resistance, are re-emerging as a community-acquired meticillin-resistant S aureus (MRSA) clone, and represent a sister lineage to pandemic hospital-acquired MRSA.
Australia↗