Reevaluations of disk diffusion susceptibility testing interpretive criteria for lomefloxacin and norfloxacin using fluoroquinolone-resistant isolates.

The current National Committee for Clinical Laboratory Standards interpretive criteria for disk diffusion susceptibility testing of lomefloxacin and norfloxacin were reevaluated using a test panel of 298 bacteria (200 with ciprofloxacin minimum inhibitory concentrations (MICs) at > or = 4 micrograms/ml). MICs were correlated with the diameter of zones of inhibition by regression statistics and error-rate bounding methods. Modifications of the interpretive criteria for lomefloxacin disk susceptibility testing are proposed as follows: susceptible at > or = 20 mm and resistant at < or = 16 mm, a 2-mm decrease of existing break-point zones.

Multiplex PCR for identifying mycobacterial isolates.

Aims: To develop a multiplex polymerase chain reaction (PCR) method to facilitate identification of mycobacterial isolates.

Methods: Type strains of 14 species of mycobacteria and 56 clinical isolates were lysed by boiling in TE Triton. The lysate (5 microliters) was used directly in a PCR reaction incorporating three pairs of PCR primers expected to amplify fragments from the genome of (a) all mycobacteria, (b) Mycobacterium tuberculosis complex only and (c) M avium only.

Evaluation of a PCR based method for identification of mycobacterial isolates.

In recent years an increasing number of mycobacterial species have been described as causing disease in humans. Identification of isolates to the species level is essential for evaluation of the significance of an isolate. Conventional methods for identification based on selective inhibitors of growth and biochemical reactions are slow.

Cross-resistance analysis for DU-6859a, a new fluoroquinolone, compared to six structurally similar compounds (ciprofloxacin, clinafloxacin, fleroxacin, levofloxacin, ofloxacin, and sparfloxacin).

Emerging resistance to the current fluoroquinolones has encouraged synthesis of new compounds in this class. We have evaluated the activity of DU-6859a, a novel halogenated quinolone, against a panel of 300 bacteria, relative to the activity of ciprofloxacin, clinafloxacin, fleroxacin, levofloxacin, ofloxacin, and sparfloxacin. DU-6859a was the most active of the fluoroquinolones studied and retains potentially useful activity against 80% of isolates resistant (minimum inhibitory concentration, > or = 4 micrograms/ml) to ciprofloxacin.

Susceptibility to levofloxacin predicted from in vitro susceptibility testing results obtained with ciprofloxacin and with ofloxacin.

A test battery of bacterial strains with a high incidence of resistance to fluoroquinolones was studied to determine the extent to which susceptibility to levofloxacin could be predicted from susceptibility tests performed with ciprofloxacin or ofloxacin as reagents. Isolates susceptible or intermediately susceptible to ofloxacin (MICs < or = 4 micrograms/ml) may be regarded as susceptible to levofloxacin, with the exception of Enterococcus faecium. Ciprofloxacin-susceptible isolates (MICs < or = 1 micrograms/ml) were also completely susceptible to levofloxacin.

The ribosomal intergenic spacer region: a target for the PCR based diagnosis of tuberculosis.

Setting: DNA Diagnostics, The National Diagnostics Centre and University College Hospital, Galway, Republic of Ireland.

Objective: To investigate the possibility of developing a DNA probe to distinguish the members of the Mycobacterium tuberculosis complex and develop an assay for the detection of M. tuberculosis in sputum.

PCR based fingerprinting of Enterobacter cloacae.

An outbreak of lower respiratory tract infection with Enterobacter cloacae occurred in an intensive care unit in a university teaching hospital. Random amplification of polymorphic DNA (RAPD) was used to assist in the investigation of the outbreak. The technique was readily applied to this organism and permitted differentiation between strains which had identical biochemical profiles and antibiograms.

A comparison of antimicrobial sensitivities of urinary pathogens for the years 1980 and 1990.

Urinary tract infection is a major cause of morbidity in both the hospital and community which often requires empirical therapy. We have retrospectively studied laboratory diagnosed urinary tract infections for the years 1980 and 1990 to document the common pathogens and antimicrobial susceptibility patterns. In 1990 a significantly lower proportion of specimens yielded Proteus sp.

Use of polymerase chain reaction for early identification of Mycobacterium tuberculosis in positive cultures.

Aims: To develop a readily applicable polymerase chain reaction (PCR) based technique which would permit the identification of Mycobacterium tuberculosis complex isolates from Bactec phials at an earlier stage than currently available methods.

Methods: Mycobacterial cells cultured in Bactec 12B medium were harvested by centrifugation. The cells were lysed by heating in distilled water.

Tuberculosis in the west of Ireland 1986-1990.

A review of mycobacteria isolated from clinical samples from the Western Health Board Area (WHBA) for the years 1986 to 1990 was performed to establish the pattern of mycobacterial infection. The incidence of microbiologically proven cases of tuberculosis (13.3/100,000) and of sputum smear positive cases (6.

The microbial flora of in-use blood pressure cuffs.

The capacity of blood pressure cuffs to act as vehicles of hospital infection has been recognised. We describe the microbial flora of in-use DINAMAP blood pressure cuffs used in the operating theatres and one recovery room in a teaching hospital. Our results show significant microbial contamination of in-use blood pressure cuffs.

Intrapericardial bleomycin for the management of cardiac tamponade secondary to malignant pericardial effusion.

A patient with malignant pericardial effusion with cardiac tamponade was treated by the instillation of intrapericardial bleomycin. The tumour deposits elsewhere in the body continued to progress and eventually killed the patient, but drainage and one dose of intrapericardial bleomycin prevented further episodes of pericardial effusion.

Ulcerative enteritis--atypical features.

A 40 year old man with two month history of vomiting and weight loss, was found to have multiple strictures in his small bowel. Investigations outruled known causes of small bowel ulceration, and the flat bowel mucosa did not respond to a gluten free diet. Treatment with steroids conferred a temporary benefit, however, small bowel ulceration persisted.