John Magee

An investigation of a nosocomial outbreak of Clostridium difficile by pyrolysis mass spectrometry

Isolates from a presumptive nosocomial outbreak of Clostridium difficile infection at a large teaching hospital were typed by pyrolysis mass spectrometry (PMS) and antibiograms. One isolate, from the putative index case, was dissimilar from the outbreak strain, but 24 isolates from 16 patients were indistinguishable by both methods. The outbreak centred on two wards for the acute care of the elderly, with a few cases elsewhere. Transfer of patients appeared to be the route of transmission between wards. There was a significant fall in the incidence of cases following intervention by the Infection Control Unit. This included ward inspection, advice on antibiotic usage and advice on prevention of faecal-oral transfer, particularly by proper handwashing. Subsequent monitoring of C. difficile infection showed a background of sporadic, dissimilar isolates with occasional apparent cross-infection incidents limited to a few patients. In suspected outbreaks, patterns of antibiotic susceptibility may be useful in initial screening, before referral for more sophisticated typing. There was excellent correlation between PMS results, antibiograms and epidemiological information.

PCR-ribotyping and pyrolysis mass spectrometry fingerprinting of environmental and hospital isolates of Clostridium difficile

The relationships between environmental isolates of Clostridium difficile were examined by two typing methods, PCR ribotyping and pyrolysis mass spectrometry (PyMS). The 184 isolates were divided into 23 different PCR ribotypes, 13 of which were producers of toxins A and B; the remaining 10 types did not produce either toxin A or B. PyMS analysis resolved 31 groups with 60 (32.5%) isolates in one group (group 9). In both methods most of the isolates showed similar clustering. PCR ribotypes of the environmental isolates were compared with those of clinical isolates that had been typed previously. Seventeen PCR types (13 toxigenic PCR types and four non-toxigenic types) were found in both sets of isolates.

The 1995 list : Proposed new bacterial taxa and proposed changes of bacterial names published during 1995 and considered to be of interest to medical or veterinary bacteriology (an informational note)

A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.

Proposed new bacterial taxa and proposed changes of bacterial names published during 1997 and considered to be of interest to medical or veterinary bacteriology

A list of names of bacteria published or validated in 1997 is presented. Comments are made of the tendency to base names of new taxa on a single bacterial strain and the consequences for reliable descriptions that this tendency implies.

Epidemiological typing of Klebsiella pneumoniae by pyrolysis mass spectrometry

Thirteen isolates of ceftazidime-resistant Klebsiella pneumoniae from a suspected cross-infection outbreak involving patients on an intensive care unit and a haematology ward were examined in pyrolysis-mass spectrometry (Py-MS), along with eight concurrent non-outbreak-associated clinical isolates of klebsiellae as controls. Py-MS showed tight clustering of the suspected outbreak isolates, suggesting cross-infection with a single strain. Non-outbreak isolates were clearly distinct from one another and from the outbreak strain. The results confirm that Py-MS is a powerful tool for rapid strain comparison in investigations of cross-infection incidents.

The 1997 list: proposed new bacterial taxa and proposed changes of bacterial names published during 1997 and considered to be of interest to medical or veterinary bacteriology

Abbreviations used: IJSB = International Journal of Systematic Bacteriology; LAM= Letters of Applied Microbiology; JCM = Journal of Clinical Microbiology; MML= Medical Microbiology Letters; ; FEMS ML=FEMS Microbiology Letters; JAB = Journal of Applied Bacteriology; ATCC=American Type Culture Collection; DSM=Deutsche Sammlung von Mikroorganismen; NCTC=National Collection of Type Cultures; LMG=Laboratorium Microbiologie Gent Culture Collection; NCIB =National Collection of Industrial Bacteria; CCUG= Culture Collection University Goteborg; CIP=Collection Institut Pasteur; PCM=Polish Collection of Microorganisms.

Proposed New Bacterial Taxa and Proposed Changes of Bacterial Names Published During 1998 and Considered to be of Interest to Medical or Veterinary Bacteriology: An informational note

Summary A list of names published or validated in 1998 is presented. In continuation of our previous efforts (Frederiksen et al.1998/1999), we present a 1998 list of new names considered to be of interest to medical and veterinary bacteriology. The following 45 bacterial names were published in 1998 in articles in the International Journal of Systematic Bacteriology (IJSB) (i. e. validly published) or published elsewhere and included in 1998 on the validation lists of IJSB (i. e. validated).

The 1998 list

A list of names published or validated in 1998 is presented.

The 1995 list. Proposed new bacterial taxa and proposed changes of bacterial names published during 1995 and considered to be of interest to medical or veterinary bacteriology. An informational note.

A list of names published or validated in 1997 is presented. We also comment on the tendency to base names of new taxa on a single bacterial strain, and the consequences for reliable descriptions that this tendency implies.

Pyrolysis Mass Spectrometry: A Predictor of Clinical Response to Treatment in Pulmonary Opportunist Mycobacterial Infection: Preliminary Work with M. malmoense

Pyrolysis mass spectrometry (Py-MS) yields data reflecting overall cell composition. The changes in composition induced by treatment with rifampicin and ethambutol, alone and in combination, were investigated for a collection of seven strains of Mycobacterium malmoense from pulmonary infections. Two strains, both from patients that had responded to therapy with this combination, showed large changes in composition from control, untreated cultures. The difference was particularly marked for the ethambutol treated cultures. Four strains, all from patients who had failed to respond to therapy with this combination, showed minimal changes in composition for all treatments. The remaining strain also showed minimal treatment-induced change, but, for this patient, therapy with the combination had proved successful. Minimum inhibitory concentrations (MICs) were determined radiometrically. All strains showed MICs < 0.5 microgram/mL for rifampicin (sensitive) and of 8 micrograms/mL for ethambutol (resistant). MIC results did not correlate with clinical response, whereas the Py-MS results correlated with clinical response for six of the seven isolates. Py-MS may have a role in predicting effective therapy for this problem group.