False-positive immunoassay for Chlamydia in urine.
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Bacteriuria↗
Biomedical subjects
E O Caul
Publications and source records attributed to E O Caul.
An assessment of sputum induction as an aid to diagnosis of respiratory infections in the immunocompromised child.
Sputum induction using nebulised hypertonic saline was performed in two groups of immunocompromised children, one group with symptoms of respiratory infection and one group without. The asymptomatic group were bone marrow transplant (BMT) recipients, all seropositive for cytomegalovirus infection (CMV). Organisms were identified in three of 14 induced sputum specimens obtained from the symptomatic group (CMV N = 1, Haemophilus influenzae N = 2), but in none of 12 specimens from the asymptomatic group. Adverse effects encountered were minor. Four symptomatic patients with negative induced sputum samples underwent bronchoalveolar lavage, and no further organisms were identified. Sputum induction can be a useful adjunct to the diagnosis of respiratory pathogens in this group of patients.
Adolescent↗
The laboratory diagnosis of male Chlamydia trachomatis infections--a time for change?
We carried out a two-phased study comparing the effectiveness of first-catch early morning urine (FCU) samples against urethral swabs for the detection of C. trachomatis in men. Four hundred and seventeen new and re-booked consecutive men, who attended the Department of Genito-Urinary Medicine, Bristol, having held their urine overnight, were recruited. Patients who had received antimicrobial chemotherapy in the preceding 2 months were excluded. Early morning FCU samples were obtained from 208 men followed by urethral swabs for the detection of C. trachomatis (phase I) and this order of collection was reversed for the remaining 209 patients (phase 2). A last-catch urine (LCU) was also obtained from all patients. All urethral and urine samples were examined by an amplified enzyme immunoassay (IDEIA, Dako Diagnostics Ltd). Initially, discordant samples were critically examined by direct immunofluorescence (Syva, 'Microtrak') which was used as the 'gold' standard in this study. We have shown that overall 42 and 4.7% of our symptomatic and asymptomatic male patients respectively were positive for C. trachomatis antigen by IDEIA. Furthermore 86.4 and 91.0% (phases 1 and 2) of the total C. trachomatis positive samples were detected by examination of an FCU sample. In contrast only 66.0 and 65.5% (phases 1 and 2) of the total positives were identified by examination of an urethral swab. These results show that an FCU sample not only has the advantage of being a non-invasive procedure but is also a very sensitive method, compared to swabbing the urethra for the detection of C. trachomatis.(ABSTRACT TRUNCATED AT 250 WORDS)
Antigens, Bacterial↗
The differentiation of Chlamydia species by antigen detection in sputum specimens from patients with community-acquired acute respiratory infections.
An amplified enzyme immunoassay (IDEIA III: Dako Diagnostics Ltd) for detecting genus-specific chlamydia antigen was evaluated prospectively on 286 respiratory specimens from 275 patients presenting with community-acquired pneumonia or persistent chest infection. Nineteen patients had evidence of recent chlamydial infection, having two or more positive sputum or serological markers. Sputa from two other patients were ELISA-positive in the absence of other positive criteria and were regarded as false-positive results. When compared with a direct immunofluorescence test for chlamydial elementary bodies (EBs) using a genus-specific monoclonal antibody, the ELISA gave a positive predictive value of 91% and a negative predictive value of 99%. Non-specific problems with a wide variety of other micro-organisms isolated from the sputa were not encountered. Attempts to differentiate between Chlamydia psittaci, Chlamydia pneumoniae and Chlamydia trachomatis using genus-specific lipopolysaccharide reactive--and species-specific major outer membrane protein--monoclonal antibodies were encouraging and results were substantiated, in most patients, by the species-specific serological assays of the whole-cell-inclusion immunofluorescence or micro-immunofluorescence assays. The study demonstrated that antigen detection techniques offer scope for routine laboratories to diagnose chlamydial respiratory infections rapidly and reliably and may enable differentiation to species level. Although immunofluorescence offers marginally greater sensitivity and specificity when compared with ELISA, the latter is less subjective and less demanding. Sixty-eight per cent of these infections would have remained undiagnosed despite the general availability of ELISA tests.
Adult↗
Pneumonia due to Legionella bozemanii and Chlamydia psittaci/TWAR following renal transplantation.
Chlamydia and Legionella are recognized causes of atypical pneumonia. A case of pneumonia due to Chlamydia psittaci/TWAR and Legionella bozemanii following renal transplantation is described. Legionella bozemanii infection was diagnosed by a rise in antibodies and by isolation of the organism from bronchoscopy specimens. It is unusual to find pneumonia caused concomitantly by two such agents. This case, despite the fatal outcome, emphasises the necessity for a comprehensive approach to the diagnosis of atypical pneumonia, including culture for Legionella, especially in immunocompromised patients.
Female↗
A prolonged outbreak of ornithosis in duck processors.
In 1985 an outbreak of ornithosis affected 13 of 80 (16%) workers in a duck-processing plant. New employees were three times more likely to become cases than established employees. The highest attack rate was in those on the production line. Following the outbreak, an occupational health scheme was set up to monitor the health of new recruits to the company. Serological evidence of recent infection was demonstrated in 18 of 37 (49%) new employees tested in the first 3 months of employment. Five (14%) also had clinical evidence of ornithosis. Veterinary investigation of the ducks demonstrated a high proportion with asymptomatic chlamydial infection. It is suggested that ornithosis may be more common in duck processors than is currently supposed. Strategies to reduce occupational risks are discussed.
Abattoirs↗
The cloning, sequencing and expression of a major antigenic region from the feline calicivirus capsid protein.
RNA purified from the feline calicivirus (FCV) F9 vaccine strain was used to prepare a cDNA library in the expression vector lambda gt11. The library was screened for expression of FCV antigen using a rabbit antiserum prepared against purified FCV. A 330 bp cDNA clone was identified and used as a probe to obtain a larger overlapping clone of 1369 bp. Comparative sequence analysis with the CFI and F4 strains showed that the clones were derived from the 3' open reading frame encoding the capsid protein. The region encoded by the 330 bp clone was shown to be variable in the three strains compared, and therefore the probable location of major antigenic variation. This clone was expressed in a bacterial system and antiserum to the recombinant protein was used in immunoblots to confirm that this clone was derived from the gene encoding the capsid protein. From these immunoblots, several other capsid-related polypeptides were identified. Comparison with immunoblots using post-vaccination cat sera showed the antibody response in the cat was directed mainly against the capsid protein. Antiserum to the recombinant protein was shown to be effective in neutralizing the infectivity of FCV, indicating that at least one major neutralizing epitope had been cloned.
Amino Acid Sequence↗
Primary humoral antibody response to Coxiella burnetii, the causative agent of Q fever.
Of 147 patients with acute Q fever diagnosed during a major outbreak in Birmingham, England, in early summer 1989, 41 provided sets of sera which allowed us to make a detailed analysis of the primary humoral immune response. Antibody titers specific for Coxiella burnetii were measured by the complement fixation test and by an immunoglobulin M (IgM)- and IgG-specific indirect immunofluorescence test. The relative avidity of specific IgGs was determined by the indirect immunofluorescence test with and without treatment of antigen-antibody complexes with 8 M urea. The IgG subclass responses after primary infection and their avidities were also determined for a limited number of paired serum specimens. Specific IgM titers persisted for more than 6 months in the majority of cases and were therefore not a sufficient criterion for the diagnosis of recent infection. However, for serial samples the antibody titer ratios (IgG/IgM) and the ratios (IgG titer with treatment/IgG titer without treatment) that indicated relative avidity changed significantly, depending on the time postinfection. Within the IgG class, the C. burnetii-specific antibody response over time was almost exclusively represented by subclass 1 molecules, which thus showed affinity maturation.
Antibodies, Bacterial↗
Cloning of noncultivatable human rotavirus by single primer amplification.
A novel, sequence-independent strategy has been developed for the amplification of full-length cDNA copies of the genes of double-stranded RNA (dsRNA) viruses. Using human (Bristol) group C rotavirus as an example, a single amino-linked modified oligonucleotide (primer 1) was ligated to either end of each dsRNA genome segment by using T4 RNA ligase. Following reverse transcription, annealing, and repair of cDNA strands, amplification of the viral dsRNA genome was accomplished by polymerase chain reaction using a single complementary oligonucleotide (primer 2). Northern (RNA) hybridization of cDNA to virus dsRNA indicated that it was possible to generate cDNA representing the complete genome from very small clinical samples. This technique was used to determine the complete nucleotide sequence (728 bp) and coding assignment of gene 10, which revealed an open reading frame of 212 amino acids with limited homology to NS26 from human group A rotavirus. In contrast to previous tailing methods, the addition of one defined primer allowed unequivocal identification of terminal nucleotides and should be generally applicable to viruses with segmented dsRNA genomes and especially for analysis of clinical samples, for which very limited quantities of biological material are available.
Amino Acid Sequence↗
Infection with small round structured viruses: England and Wales 1981-1990.
Infection with small round structured viruses (SRSV) usually causes an acute, but short-lived, attack of gastroenteritis in which vomiting is a prominent feature. Most documented outbreaks have occurred in institutional and catering establishments and infected food handlers are often implicated. Reports of SRSV infection have risen substantially during the last decade partly due to an increase in the number of laboratories able to examine samples for this organism. Ascertainment is likely to remain low, however, until a sensitive, simple, reliable and economical method of detection becomes routinely available.
Adolescent↗
Zidovudine after occupational exposure to HIV.
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HIV↗
Influenza vaccination in adults with cystic fibrosis.
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Adult↗
Electron microscopic reporting of gastrointestinal viruses in the United Kingdom, 1985-1987.
We examined some epidemiological features of the viruses associated with gastrointestinal illness, using national data reported by electron microscopists in the United Kingdom. During the 3 years analyzed (1985-1987), a total of 1,993 positive detections of astroviruses, caliciviruses, coronaviruses, and small round structured viruses (SRSVs) were reported. In 1 year of this period, 8,210 rotaviruses were reported. More than 90% of the astroviruses and caliciviruses were detected in children under 5 years of age, while coronaviruses and SRSVs were detected in adults as well as children. Detections of astroviruses increased in the winter and were infrequent during the summer, a seasonal pattern similar to that observed for rotaviruses. There was some variability between reporting regions in rates of detection of fecal viruses. We have attempted to identify the reasons for this. We make suggestions for improving the detection of human fecal viruses, and we recognize the need for continued surveillance of these agents.
Adolescent↗
Human parvovirus B19 specific IgG, IgA, and IgM antibodies and DNA in serum specimens from persons with erythema infectiosum.
To determine the diagnostic use of different markers of acute parvovirus B19 infection, serum specimens obtained from 128 persons with erythema infectiosum were tested for specific immunoglobulin G (IgG), IgA, and IgM antibodies by capture enzyme immunoassay (EIA) using Chinese hamster ovary (CHO) cell-expressed B19 antigen, and tested for circulating B19 DNA by polymerase chain reaction (PCR). A significant rise in specific IgG and IgA antibodies was detected in 87% and 77%, respectively, of persons from whom acute- and convalescent-phase serum specimens were available. Specific IgA antibodies were detected in single serum specimens from 90% of cases and were present in 22 (18%) of 120 persons from a control group without a history of recent exposure to B19. Specific IgM antibodies were detected in 97% of cases and one person (1%) from the control group. B19 DNA was detected in 94% of cases and was absent in 20 persons from the control group positive for both IgG and IgA antibodies. Serum specimens obtained between 4 and 6 months after onset of illness from six additional persons were also tested. All had specific IgG antibodies, four (67%) had IgA, five (83%) had IgM, and none had detectable B19 DNA. Our data indicate that 1) specific IgA antibodies are too persistent to be a useful indicator of recent B19 infection; 2) specific IgM antibodies are the most sensitive indicator of acute B19 infection in immunologically normal persons but can persist up to 6 months; and 3) B19 DNA can often be detected up to 2 months after onset of illness even in immunologically normal hosts and might be a useful adjunct test for diagnosis of acute B19 infection.
Adolescent↗
Molecular cloning, sequence analysis and coding assignment of the major inner capsid protein gene of human group C rotavirus.
The VP6 gene of human group C rotavirus was cloned and sequenced. Hybridization to the human group C and the porcine group C/Cowden dsRNA genomes assigned this coding sequence to segment 5. The complete human VP6 sequence contained an open reading frame of 1185 nucleotides (395 amino acids; deduced Mr 44,669 Da). The protein sequence demonstrated low homology with the group A VP6 sequences (41.7 to 42.7%) and high homology (88.9%) with the porcine group C VP6 sequence. However, the protein sequence alignments revealed a region of 10 amino acids that were significantly different between the human and the porcine group C viruses.
Amino Acid Sequence↗
Detection of group B and C rotaviruses by polymerase chain reaction.
We adapted the polymerase chain reaction (PCR) to detect the noncultivatable group B and C rotaviruses and introduced a simple and convenient technique to purify viral RNA from stool specimens. Double-stranded RNA present in stool extracts was purified by adsorption to hydroxyapatite and was used as the template for reverse transcription and polymerase amplification. Primer pairs specific for group B (gene 8) and group C (gene 6) rotaviruses were selected to amplify group-characteristic sizes of cDNA copies readily identifiable in ethidium bromide-stained agarose gels. These primer pairs were used separately in individual PCR assays or were pooled with a primer pair specific for group A rotavirus (gene 9) in a combined PCR assay for the simultaneous detection of all three rotavirus groups. The method was very sensitive and was used to identify both human and porcine strains of group B and C rotaviruses in stool specimens. A second PCR amplification with internal group-specific primers served to increase further the sensitivity of the test and to confirm the diagnostic results obtained in the first amplification.
Base Sequence↗
Foodborne gastroenteritis due to Norwalk virus in a Winnipeg hotel.
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Feces↗
Group C rotavirus associated with fatal enteritis in a family outbreak.
A family outbreak of gastroenteritis involving three adults and three children is described in which diarrhoea and vomiting were the main clinical features. One infant died in whom no pathogens could be detected in either small or large intestinal postmortem samples. Stool samples from two symptomatic siblings contained rotaviruses as demonstrated by electron microscopy. Both of these faecal samples were negative when assayed in a group A specific rotavirus enzyme-linked immunosorbent assay (ELISA) and subsequent genomic analysis of these rotaviruses was suggestive of group C rotavirus. Serological evidence showed that these atypical rotaviruses were members of serogroup C. Other atypical rotaviruses in faecal samples from sporadic cases in symptomatic children were detected over a similar time period and location. These had electrophoretic RNA profiles similar to those in the family outbreak. Furthermore, seroepidemiological studies detected group C rotavirus antibody in blood donors resident in the location of the family outbreak.
Adult↗