Prevalence and distribution of plasmid-mediated quinolone resistance genes in clinical isolates of Escherichia coli lacking extended-spectrum beta-lactamases.

OBJECTIVES: The aac(6')-Ib-cr gene has been described in plasmids from CTX-M-15-producing Escherichia coli in the worldwide ST131 lineage, but has not been systematically sought in other quinolone-resistant strains in the UK. A rise in quinolone resistance in bacteraemia isolates in the UK preceded the increased prevalence of CTX-M-producing strains. This study aimed to describe the presence of plasmid-encoded quinolone resistance genes in historical and current strains of E. coli not producing extended-spectrum beta-lactamases (ESBLs). METHODS: Ciprofloxacin-resistant, non-ESBL-producing E. coli isolates included nationally distributed isolates from the BSAC UK bacteraemia surveillance programme between 2001 and 2005, urinary isolates from a regional project in 2000 and local strains in 2006. The aac(6')-Ib-cr gene was detected using PCR followed by restriction fragment length polymorphism analysis. Multiplex PCR was used to detect qnr genes. Isolates with aac(6')-Ib-cr were assessed for aminoglycoside susceptibilities and were serotyped. RESULTS: The prevalence of the aac(6')-Ib-cr gene was 3% and 9% in current local urinary and historic national bacteraemia quinolone-resistant non-ESBL-producing E. coli, respectively. Of 521 regional urinary E. coli isolates from 2000, 14 were norfloxacin-resistant, none of which carried the aac(6')-Ib-cr gene. National positive bacteraemia isolates from 2001/2 were type O102-ST405 and, in 2004/5, types O1-ST645 and O25-ST131. Positive local urinary isolates from 2006 included serotypes O1 and O25. CONCLUSIONS: In the UK, aac(6')-Ib-cr occurs in E. coli in the absence of CTX-M-15, but with a restricted serotype distribution. Its presence in widespread bacteraemia isolates of a single type from 2001 to 2002, prior to the spread of CTX-M-15 in Britain, might suggest a lineage from which plasmid recombination occurred in man or other species.

A radioimmunoassay for hepatitis A antigen and antibody.

The HAVAB radioimmunoassay for the detection of antibody to hepatitis A is assessed. Its modification to detect virus in faecal samples is described and in this it was found to be more sensitive and specific than electron microscopy.

Chronic hepatitis C in long term survivors of haematological malignancy treated in a single centre.

AIMS: To investigate the impact of hepatitis C virus (HCV) infection in long term survivors of haematological malignancy treated before the introduction of blood donor screening in September 1991. METHOD: Patients were tested for evidence of HCV infection by third generation enzyme linked immunosorbent assays, a recombinant immunoblot assay and reverse transcriptase polymerase chain reaction. Serum aspartate aminotransferase activities were measured. The number and type of blood component units received by each patient were recorded. RESULTS: Forty two patients were studied who had received a total of 7143 blood component units. Two patients (4.8%) were found to have HCV infection, both had histological evidence of chronic active hepatitis, and one is now receiving treatment with alpha-interferon. Both of these patients had been missed by the ongoing look-back programme which aims to detect recipients of all known HCV infected blood components. CONCLUSION: Although HCV infection affects a minority of long term survivors of haematological malignancy, infected patients may benefit from alpha-interferon treatment. The screening of all patients treated for haematological malignancy before September 1991 is advocated.

Report of a joint DMRQC/Organon field trial to detect hepatitis A IgM by ELISA.

The results of a field trial of a joint DMRQC/Organon ELISA kit for the detection of hepatitis A IgM antibody are reported. The participating laboratories were asked to use the kit to test a panel of 360 specimens consisting of duplicate coded samples of 180 sera. The panel was also tested by MACRIA in the Virus Reference Laboratory, Colindale. The ELISA was shown to be specific and sensitive giving good discrimination between acute and late convalescent hepatitis A sera. It was proposed that the same cut-off control as is used in the RIA (equivalent to 10 RIA units) should be adopted for the ELISA also.

Small virus particles in faeces of patients with infectious hepatitis (hepatitis A).

Forty-one faecal samples from infectious-hepatitis patients and their contacts were investigated for the presence of hepatitis-A-associated viral particles. Of these, 16 gave a positive result by immune electronmicroscopy or caesium-chloride density-gradient centrifugation. The latter method proved invaluable in detecting small numbers of virus particles. The particles found had buoyant density of 1-34-1-35 and a size range of 21-28 nm. Epidemiological evidence suggested that they might be the causative agent of hepatitis A.

Interferon assay as a viral diagnostic test.

The early production of interferons (IFNs) following viral infection has led to their detection being investigated as a method of diagnosis of such infections. The assay described here for alpha-IFN can be completed in one day and therefore has advantages over previously used bioassays. However, because production of IFN is transient, collection of samples must be soon after the onset of illness. For this reason the assay is more useful in cases where patients are seen early after the onset of symptoms. We have been looking at several such groups; the one reported here is children admitted to a paediatric infectious disease unit. 24/34 sera where a virus was found were positive for IFN and 14/52 where no virus was isolated. Control sera and those from patients with a bacterial infection were negative for IFN. We feel that the test is useful for certain groups of patients and are continuing to assess the assay for inclusion as a routine diagnostic test.

Tropical aspects of viral hepatitis. Hepatitis E.

Hepatitis E (HEV) is a faeco-orally transmitted hepatitis virus. It has many features similar to hepatitis A but some differences, notably the high mortality caused by HEV in pregnant women. A vaccine is being developed but at the moment only a clean water supply will reduce the number of cases in areas where the virus is endemic.

Acute bronchitis in the community: clinical features, infective factors, changes in pulmonary function and bronchial reactivity to histamine.

A descriptive study of acute bronchitis in patients without pre-existing pulmonary disease was undertaken in the community during the winter months of 1986-87. Forty-two episodes were investigated in 40 individuals. The cardinal symptom was the acute onset of cough (100%), usually productive (90%). Wheezing was noted by 62% of patients, but heard on auscultation in only 31%. A potential pathogen was isolated in 29% of cases with a virus (eight cases) being identified more frequently than either Mycoplasma pneumoniae (three cases) or a bacterium (three cases). The acute illness was associated with significant reductions in forced expired volume in 1 second (P less than 0.02) and peak expiratory flow (P less than 0.001) but not forced vital capacity compared to 6 weeks later. Ten of the 27 (37%) patients who had a histamine challenge test performed at 6 weeks had a PD20 of less than 7.8 mumol histamine. Thirty-nine episodes (93%) were treated with antibiotics by the general practitioner, the clinical course being unremarkable apart from one patient who developed a lingular pneumonia despite antibiotic therapy. Further studies are required to assess whether acute bronchitis causes an acute increase in bronchial hyperresponsiveness and whether either antibiotics or inhaled bronchodilators or anti-inflammatory therapy has a useful role in the management of this predominantly viral illness.

Anonymized sero-survey of HIV in a genitourinary medicine clinic population.

An anonymized sero-survey of the prevalence of HIV antibody was performed at an inner city Genitourinary medicine clinic in Birmingham. In 1991 8686 patients undergoing routine serological syphilis tests were anonymously tested for HIV antibodies once during the year. Demographic information was recorded for each sample but they were otherwise unlinked. There were 31 samples which tested positive for anti-HIV 1 from this group compared with 13 diagnosed by concomitant voluntary named testing. Sero-prevalence rates of 0.17% for women and heterosexual men and 4.37% for homosexual/bisexual men were found. No drug users tested positive. The survey provided evidence of occult disease outside the recognized risk behaviour patterns of homosexual men and injecting drug users outside London.

Prevalence of GB virus-C/hepatitis G virus infection in an antenatal population.

It is difficult to explain the high levels of infection seen with GBV-C/HGV if transmission relies on the parenteral route. A group of young women was investigated in order to establish the prevalence of infection in this age group of the general population and perhaps indicate other possible routes of infection, searching for both GBV-C/HGV RNA and HGV E2 antibodies. Evidence of infection was found in 11.8%. This is a higher prevalence than that found in blood donors but lower than in prostitutes. Evidence is accumulating from various groups that sexual/ close contact may result in transmission of this virus.

Hepatitis E infection in the UK.

A modification of a commercial assay for anti-HEV to allow detection of specific IgM has been validated. Its use has shown that acute cases of HEV do occur in the UK. To date these have all been patients returning from highly endemic areas.

Neopterin and beta-2 microglobulin levels in asymptomatic HIV infection: the predictive value of combining markers.

The concentrations of neopterin, beta-2 microglobulin, p24 antigen, anti-p24 antibody, and alpha-interferon were determined in the sera of 25 asymptomatic anti-HIV positive patients (CDC stages II and III) over a 50 month period (38 months retrospectively and 12 months prospectively). Evaluation of the data allowed the derivation of a threshold of abnormality for both neopterin and beta-2 microglobulin. Pre-AIDS (CDC groups IVa, IVc2, IVe) developed in 6 of the 26 patients within 18 months of the first abnormal value of beta-2 microglobulin, and within 12 months of the first abnormal value of neopterin. Combining the abnormal results of neopterin, beta-2 microglobulin, p24 antigen, and alpha-interferon allows prediction of progression to pre-AIDS within 18 months for most asymptomatic patients.

Non-A, non-B hepatitis in patients receiving blood products.

A group of patients all regularly receiving blood products for a congenital bleeding disorder were investigated for evidence of past infection with hepatitis A and B, and compared with a control group. There was a significantly higher percentage of the test group who had markers of infection with these viruses, and 15 patients had symptoms of hepatitis during the study. The greater number of the test group showing evidence of past hepatitis A infection can only really be explained by acquiring antibody from blood products, especially since none of our patients with hepatitis had hepatitis A and there is evidence that this is not an infection associated with blood products. We conclude that the majority of patients in our study showing symptoms of hepatitis had non-A, non-B hepatitis.

Accuracy of plasma HIV RNA quantification: a multicentre study of variability.

Inaccurate quantification of plasma HIV RNA concentration may be detrimental to patient care, yet little is known about how reproducible results are within and between laboratories. Each week between January and April 1998 a different laboratory represented at the Public Health Laboratory Service HIV Diagnosis Forum sent aliquots of the same anti-HIV positive plasma specimen by First Class Mail to the other 12 laboratories and to itself. Aliquots were frozen on receipt and examined in the next assay run. At the end of the 13 week period each laboratory reported their findings and provided further information about the specimen that they had dispatched. The correlation of results between laboratories and between the four different assay kits used was generally satisfactory. HIV RNA concentrations determined by the Roche Monitor and AcuGen kits were higher, and by the Chiron Quantiplex v 2.0 kit lower, than average. The Chiron Quantiplex gave the most reproducible concentrations. Nine 'below detection limit' results occurred, associated with three specimens. One specimen gave a below detection limit result in every one of six laboratories using the Organon Teknika Nuclisens HIV-1 QT kit, and was found to contain viral RNA of HIV-1 clade G. Another below detection limit result was probably due to technical error, and the remaining two to assay insensitivity. The findings suggested that an unsustained change in HIV RNA of

An outbreak of infectious hepatitis investigated using radioimmunoassays for hepatitis A virus antibody.

An outbreak of suspected infectious hepatitis in a primary school was investigated using sensitive diagnostic methods for hepatitis A. A total of 116 sera from children were tested for the presence of both IgM and IgG antibodies to hepatitis A (HAV). The results were compared to those obtained for samples from a control school. IgG antibodies were present in 45% and 10% of the children in the outbreak and control schools respectively.

Hepatitis E virus: the cause of a waterbourne hepatitis outbreak.

Newly developed assays for antibody to hepatitis E virus (HEV) were used to study 114 serum samples collected during an outbreak of enterically transmitted hepatitis that occurred in Kashmir in 1978/9. The sera included samples from patients with viral hepatitis, anicteric hepatitis, contacts of cases, and unaffected persons. A total of 71% of patients with viral hepatitis were found positive for anti-HEV specific IgG, and 75% of these were also positive for IgM. These data confirm the hepatitis E virus as the causative agent in this outbreak.