Inexpensive 4-hour micro-agar dilution susceptibility determination method.

Using a micro-agar dilution (MAD) method in which microscope slides are covered with a thin film of agar, and MICs are read microscopically after a 4-h incubation, 18 antibiotics were tested against 29 to 32 microorganisms each. Identical MICs were obtained for microscopic MAD MICs performed in duplicate in 87.1% of the antibiotic-microorganism combinations, and 97.

Demonstration of circulating pneumococcal immunoglobulin G immune complexes in patients with community-acquired pneumonia by means of an enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay was developed for quantitation of circulating immune complexes (CICs) containing specific antipneumococcal immunoglobulin G (IgG). These CICs were detected in 17 (85%) of 20 patients with bacteremic pneumococcal pneumonia, 4 (36.4%) of 11 patients with probable pneumococcal pneumonia, 3 (16.

Antigen detection in oropharyngeal secretions for rapid diagnosis of pneumococcal pneumonia.

To determine the value of detection of antigen in the oropharynx in the diagnosis of pneumococcal pneumonia, oropharyngeal secretions were cultured for the presence of Streptococcus pneumoniae and tested for the presence of pneumococcal antigen. Sputum (if available) collected on the same day was also investigated for the presence of antigen. Detection of pneumococcal antigen was found to be directly related to the severity of pneumococcal carriership or infection (p < 0.

Rapid detection of pneumococcal antigen in pleural fluid of patients with community acquired pneumonia.

Background: Detection of pneumococcal antigen may help to increase the rate of diagnosis of pneumococcal pneumonia. This study was designed to determine the value of rapid detection of pneumococcal antigen in pleural fluid from patients with community acquired pneumonia.

Methods: Thoracentesis was performed in patients suspected of having empyema and in patients with pneumonia of unknown aetiology.

The role of antigen detection in pneumococcal carriers: a comparison between cultures and capsular antigen detection in upper respiratory tract secretions.

During the winter season upper respiratory tract secretions from 166 patients with stable chronic obstructive pulmonary disease (COPD) or asthma were simultaneously cultured for Streptococcus pneumoniae and tested for pneumococcal capsular antigen. Latex agglutination was employed to investigate the effect of pneumococcal carriership on pneumococcal capsular antigen detection in upper respiratory tract secretions. All specimens originating from the oropharynx, nasopharynx and saliva were both cultured and investigated in parallel for the presence of antigen.

Detection of pneumococcal capsular antigen in the presence of penicillin in vitro.

Eight strains of Streptococcus pneumoniae were tested in vitro for their ability to produce capsular antigen in the presence of penicillin. It was found that, provided 10(6) to 10(7) pneumococci/ml were present, capsular antigen could be detected during the 72 h in which the experiment was conducted, irrespective of whether penicillin was added at 0 h or 8 h, and even when no viable pneumococci remained. When fewer pneumococci were present, capsular antigen could not be detected at any time in the presence of penicillin.

Pneumococcal antigen persistence in sputum from patients with community-acquired pneumonia.

The purpose of this study was to establish the diagnostic value of pneumococcal capsular antigen by comparing this with the results of Gram stain and culture in representative and nonrepresentative sputa during follow-up in patients with community-acquired pneumonia. Antigen was detected by a latex particle agglutination test. At the time of hospital admission, antigen was detected in 17 representative sputum specimens from 30 patients with pneumococcal pneumonia, which was comparable to the results of Gram stain and culture.

Minimum number of pneumococci required for capsular antigen to be detectable by latex agglutination.

Forty-eight strains of Streptococcus pneumoniae were tested in vitro to determine the minimum number required for pneumococcal capsular antigen to be detectable by latex agglutination. It was found that 10(6) to 10(7) microorganisms per ml were needed and that antigen remained detectable even when viable pneumococci could no longer be demonstrated.

Pneumococcal capsular antigen detection and pneumococcal serology in patients with community acquired pneumonia.

Background: Methods to determine the microbial cause of community acquired pneumonia include detection of pneumococcal antigen and measurement of pneumococcal capsular antibody response. Their usefulness compared with conventional microbiological techniques was investigated in patients with pneumonia, some of whom had been treated with antibiotics.

Methods: Pneumococcal capsular antigen was detected by latex agglutination in sputum and the results compared prospectively with results of conventional microbiological techniques in 90 patients with community acquired pneumonia.

Effect of washing sputum on detection of pneumococcal capsular antigen.

The effect of washing of sputum on detection of pneumococcal capsular antigen was investigated. A total of 357 sputa from 104 patients was tested. Antigen could be detected in 164 (46%) of the sputa in both the washed and unwashed portions, and could not be detected in either portion in a further 180 (50%) sputa.

Importance of minimizing carry-over effect at subculture in the detection of penicillin-tolerant viridans group streptococci.

Penicillin susceptibility determinations made for 14 strains of Streptococcus mitior by two different broth dilution tests revealed small numbers of tolerant strains regardless of the volumes (0.01 and 0.1 ml) of subcultured broth.

Incidence of postextraction bacteremia under penicillin cover in children with cardiac disease.

To assess the efficacy of penicillin prophylaxis as recommended by the American Heart Association to prevent the onset of bacterial endocarditis, the incidence of postextraction bacteremia was determined in 82 children with cardiac disease who were receiving prophylactic penicillin. Aerobic and anaerobic blood cultures were taken five minutes after dental extraction, as was a blood sample to assay the serum penicillin concentration. The incidence of postextraction bacteremia was 21%.

Penicillin prophylaxis in children with cardiac disease: postextraction bacteremia and penicillin-resistant strains of viridans streptococci.

The incidence of postextraction bacteremia in 82 children with dental foci and cardiac disease given parenteral penicillin prophylaxis was assessed 5 min after extraction. Penicillin concentrations were determined in blood samples obtained at the same time. Before extraction, cultures were taken from the gingival sulcus.

Penicillin tolerance in nutritionally variant streptococci.

Eleven strains of nutritionally variant streptococci were tested for their susceptibility to penicillin by a broth dilution method. All minimal inhibitory concentrations were low. It was found that plates containing only vitamin B6 (pyridoxal HCl) and cysteine did not reveal true minimal bactericidal concentrations.

Screening for penicillin tolerance in viridans streptococci by a simple disk method.

A disk method was developed for demonstrating penicillin tolerance in viridans streptococci. This was achieved by the substitution of the penicillin disk used for susceptibility testing by a disk containing penicillinase. After reincubation, penicillin-tolerant strains exhibited new growth in the area adjacent to this disk, providing a rapid screening test.