Implications of new European Union driving regulations on patients with Type 1 diabetes who participated in the Diabetes Control and Complications Trial.

AIMS: Recurrent severe hypoglycaemia in a patient with diabetes is strongly associated with a crash risk while driving. To help ensure road safety, recent changes were made to European Union driving regulations for patients with diabetes. These included the recommendation that more than one episode of severe hypoglycaemia within 12 months would lead to the loss of a driving licence. This study has assessed the impact of this regulation if applied to patients who participated in the Diabetes Control and Complications Trial. METHODS: All patients in the Diabetes Control and Complications Trial were assumed to be drivers. Repeated hypoglycaemic episodes within a year were determined during the mean 6.5 years of the study. RESULTS: Of the 1441 patients in the Diabetes Control and Complications Trial, 439 (30%) had more than one severe hypoglycaemic episode during a 12-month period of their study participation. Amongst the study groups, 312/711 (44%) of intensively treated and 127/730 (17%) of conventionally treated patients would have lost their licence at some point during the trial. The risk of licence loss increased with lower mean HbA1c , longer duration of diabetes and younger age (all P < 0.001). CONCLUSIONS: More than one episode of severe hypoglycaemia within a year was a frequent event in subjects in the Diabetes Control and Complications Trial, especially in intensively treated patients. If applied to current practice, improving road safety through these changes to European Union regulations could have a substantial impact on drivers who have Type 1 diabetes. This emphasizes the need to take into account the potential effects of severe hypoglycaemia in those who rely on a driving licence.

Daptomycin in endocarditis and bacteraemia: a British perspective.

Assessment of the place of daptomycin in the treatment of endocarditis and bacteraemia requires assimilation of data from one open-label randomized comparative clinical trial sized for equivalence, from registry data and from case reports. Selected relevant animal models and in vitro data are also considered in an effort to produce an integrated assessment of the current place of daptomycin in treatment. The evidence for the use of daptomycin is best in Staphylococcus aureus bacteraemia and endocarditis, but also includes some data on infections due to Enterococcus spp., especially if vancomycin-resistant. The emergence of resistance in a minority of patients on current dose regimens may mean that trials have to be repeated with higher doses, or the drug used in a combined therapy where rifampicin may be the best choice. In general, equivalence to comparator antibiotic regimens and a correlation for in vitro and in vivo findings have been demonstrated, but there are important gaps in the clinical data including a comparative equivalence trial in streptococcal and enterococcal endocarditis. Clinical benefit might be anticipated, but has not been proved, over aminoglycoside-containing regimens, and economic assessments are critical in the decision as to when and how daptomycin is deployed.

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.

Imported chicken meat as a potential source of quinolone-resistant Escherichia coli producing extended-spectrum beta-lactamases in the UK.

OBJECTIVES: Escherichia coli producing CTX-M-15 enzyme began to rapidly spread in the UK from around 2003 but other types also occur, notably CTX-M-14. We examined breasts from UK-reared (n = 62) and imported (n = 27) chickens as potential sources of quinolone-resistant E. coli with bla(CTX-M) genes. A further 40 samples for which the country of rearing could not be identified were examined. METHODS: During 2006, 129 fresh and frozen chicken breast fillets were purchased from retail outlets in the West Midlands. These were cultured for E. coli on CLED agar containing 8 mg/L ciprofloxacin and carrying a 10 microg cefpodoxime disc. Resistant isolates were identified and typed by RAPD fingerprinting; bla(CTX-M) was identified by PCR and genotyped by reverse-line hybridization. RESULTS: The country of rearing was identified from the packaging for 89 of 129 purchased samples. Only one of the 62 UK-reared chicken samples carried E. coli producing a CTX-M-1 enzyme, whereas 10 of 27 samples reared overseas had E. coli with CTX-M enzymes. Specifically, 4/10 Brazilian, 3/4 Brazilian/Polish/French, and 2/2 Dutch samples had E. coli with CTX-M-2 enzymes. Six of 40 samples for which the country of rearing was not known had producers of CTX-M enzymes, 5 of them with CTX-M-14. CONCLUSIONS: Quinolone-resistant E. coli with various CTX-M beta-lactamase genes that are common in human infections worldwide were found in imported chicken breasts, indicating a possible source for gut colonization. Samples from Brazil were commonly positive for E. coli with CTX-M-2, the dominant bla(CTX-M) genotype from human infections in South America, which is currently rare in clinical infections in the UK. CTX-M-15, the dominant CTX-M type in human infections in the UK, was not found in chicken isolates, suggesting that the UK-reared chickens are not a reservoir of CTX-M-15.

Control of infections due to extended-spectrum beta-lactamase-producing organisms in hospitals and the community.

Control of infection classically involves hand and healthcare hygiene, reduction of selective and ineffective chemotherapy, reduction of invasive procedures and achlorhydria and adequate staffing, along with appropriate containment and concentration of patients. Investigation and control of any continuing sources of infection in food and water supplies is important also, as is recognition of individuals carrying high-risk strains and species. The onset of infection may be distant from the time of acquisition and may critically affect epidemiological assessment of control points. Carriage may be prolonged, increasing the likelihood of recurrent infection and exacerbating the difficulty of control. Mortality associated with resistance is difficult to assess retrospectively and may not be high, complicating analysis of the success or failure of control measures.

An assessment of the efficacy of antimicrobial prophylaxis in bone marrow autografts.

Fifty-three patients undergoing autologous bone marrow transplantation received antimicrobial prophylaxis with ciprofloxacin with or without erythromycin and low dose intravenous amphotericin B. Eight patients remained afebrile throughout the neutropenic period. All other patients had one or more febrile episodes. The median time to fever after the onset of neutropenia was 7 days. There were no gram-negative organisms isolated from blood cultures during any of these episodes whereas gram-positive organisms were isolated in 28. There was one death in this series associated with sepsis. The use of low-dose prophylactic parenteral amphotericin did not prevent the subsequent successful use of full dose amphotericin for antibiotic-resistant fever. Ciprofloxacin effectively prevents gram-negative sepsis. The addition of erythromycin does little to prevent gram-positive sepsis. The use of regimens with agents with activity against gram-positive organisms is appropriate initial treatment of all febrile neutropenic episodes.

Effect of sample volume on yield of positive blood cultures from adult patients with haematological malignancy.

Six hundred and sixteen blood samples from patients with haematological malignancy were each distributed equally among three identical cells in a Malthus Microbiological Growth Analyser. The mean (SD) volumes inoculated into sets in which one, two, or three of the three bottles were positive were 37.7 (10.1) ml, 37.4 (12.9) ml, and 37.7 (10.5) ml, respectively. Overall, clinically important organisms were isolated from one bottle only with 18 cultures, from two bottles only with 19 cultures, and from all three bottles in a set with 104 cultures. If the yield from a single bottle inoculated with a mean volume of 12.6 ml blood is taken as 100%, the yield from 25.2 ml in two bottles was 110.7% and the yield from 37.7 ml in three bottles was 115.6%. The increased yield from increased volume was considerably lower than that reported from unselected groups of patients, which suggests that the magnitude of bacteriaemia is greater in patients with neutropenia. The isolation of infecting organisms from the blood of patients with neutropenia is, however, particularly important in directing chemotherapy and consequently 45 ml blood samples from these patients continue to be requested.

Haemorrhagic colitis: detection of verotoxin producing Escherichia coli O157 in a clinical microbiology laboratory.

Faeces (n = 1319) were examined over three months for the presence of non-sorbitol fermenting, verotoxin producing Escherichia coli (serotype O157). Seven isolates were found, four from patients with bloodstained diarrhoea and three from patients with no evidence of blood in the faeces. Screening of all faecal samples with specific O157 antiserum for non-sorbitol fermenting organisms and agglutination was an important adjunct to clinical and microscopic findings and helped detect cases of verotoxin producing E coli which might otherwise have been missed.

IgG enzyme linked immunosorbent assay for diagnosis of invasive aspergillosis: retrospective study over 15 years of transplant recipients.

Four commercially available Aspergillus fumigatus antigens were compared in an IgG enzyme linked immunosorbent assay by testing multiple sera from 19 patients who had received renal and hepatic allografts and who had histologically confirmed invasive aspergillosis. Raised antibody levels were found in 16 of the 19 patients. More antibody responses were detected by culture filtrate antigens, but somatic antigens often detected antibodies sooner. When antibodies to Aspergillus antigens were present before transplantation the onset of fatal disseminated infection was earlier. Antibody levels often fell to within the normal range, even in cases of fulminant disseminated infection. Repeated serology was essential for detection of an antibody response.

Automated screening of blood cultures with the Malthus microbiological growth analyser.

A total of 3347 blood cultures from patients in all hospital wards were examined on a Malthus microbiological growth analyser and by a conventional system. There was no significant difference in the total numbers of positive cultures of clinical importance between the two systems (p greater than 0.05). Staphylococcus aureus, however, was isolated more often by the conventional method (p less than 0.05). Failure of the automatic detection routine limited the potential of the Malthus system for earlier detection of positive cultures. Daily visual examination of Malthus curves and subculture of bottles not promptly attached to the apparatus were necessary to avoid missing some positive cultures. False positive rates were 13% for the Malthus system and 2% for the conventional system. The contamination rate was considerably lower in the Malthus system (p less than 0.001). Further development would be necessary for the apparatus to be acceptable for routine screening of blood cultures.

Rectal organ culture as a model for the investigation of bacterial adhesion and invasion.

A system was developed for the in vitro culture of human rectal mucosa. Its viability was proved by histological appearances and by metabolic studies. Biopsy samples were cultured in the presence of appropriate bacteria isolated from the faeces of patients with ulcerative colitis or with dysenteric illnesses. Attempts to show adhesion of bacteria to the mucosa or invasion of the cultured tissue failed. Problems with the use of this model are discussed.

Automated detection of micro-organisms in blood cultures by means of the Malthus Microbiological Growth Analyser.

A prototype Malthus Microbiological Growth Analyser was compared with conventional methods for examining blood cultures in a trial of 651 cultures mostly from patients with haematological malignancy or undergoing haemodialysis or renal transplantation. Of 100 significantly positive cultures, organisms from 82 grew in the conventional aerobic (+ CO2) bottle, 78 in the conventional anaerobic bottle and 71 in the Malthus bottle. The differences were not statistically significant (p greater than 0.05). The Malthus system detected 83.6% of significantly positive cultures earlier than the comparable conventional bottles while 7.3% positive cultures were detected earlier by the conventional system. When use of the Malthus system was restricted to the hours of 09.00 to 17.30 daily 27.3% positive cultures were detected earlier by the Malthus system and 16.4% were detected earlier by the conventional system. One of the organisms which grew in the Malthus bottle, a contaminating Staphylococcus epidermidis, was not detected by the Malthus system. Instability of electrodes resulted in 26.9% false positive cultures with the prototype Malthus system. Contamination rates in both the Malthus and conventional anaerobic bottles were lower than in the aerobic bottles.

Neutropenic enterocolitis due to Clostridium septicum infection.

Three cases of neutropenic enterocolitis are described. This unusual condition occurs almost exclusively in neutropenic patients and has a fulminating course which is almost invariably fatal without surgical intervention. The lesion is centered on the caecum and hitherto its pathogenesis has been unclear, partly because most studies have been performed on material obtained at necropsy. In these three patients, all of whom were treated surgically, Clostridium septicum was identified by specific immunofluorescence in the bowel wall of the resected specimens. Two patients also had C septicum septicaemia. Various forms of mucosal damage can be identified which predispose towards invasion of the bowel wall by this organism. These cases provide further confirmation of a primary role for C septicum in the pathogenesis of neutropenic enterocolitis.

Clostridium difficile in haematological malignancy.

Twenty patients with haematological malignancies who developed Clostridium difficile bowel infection or colonisation are described. All isolates of C difficile were toxigenic in vitro and faecal cytotoxin (toxin B) was detected in 20/26 episodes. Ten of 20 episodes with detectable faecal cytotoxin were associated with typical antibiotic associated diarrhoea. In the other 10 episodes (nine patients), there was a severe unusual illness which was associated with detection of C difficile. The unusual features of the illness were pronounced jaundice (total bilirubin greater than or equal to 44 mumol/l), abdominal pain and distension, and initial constipation followed either by diarrhoea or by large bowel stasis. Four of these patients died within seven days. Bacteraemia was often a presenting feature in neutropenic patients subsequently shown to have C difficile. This was not the case in non-neutropenic patients. Bacteraemia was commonly polymicrobial and in two cases C difficile was isolated from blood culture. The clinical implications of recognition of this atypical C difficile associated syndrome are discussed.

Neutropenic enterocolitis associated with Clostridium tertium.

A 15 year old boy being treated for relapsed acute lymphoblastic leukaemia developed severe diarrhoea and abdominal pain which worsened despite empirical antibiotic treatment. A right hemicolectomy was performed. The caecum and ascending colon showed changes typical of neutropenic enterocolitis. Clostridium tertium was isolated from faeces, blood cultures, and from the resected gut wall, with no evidence of other organisms capable of causing such a condition. As far as is known, this is the first reported case in which neutropenic enterocolitis has been associated with well documented C tertium infection, an organism previously described as a cause of bacteraemia in neutropenic patients.

Development of an internal quality assessment scheme in a clinical bacteriology laboratory.

AIM: To develop an internal quality assessment (IQA) scheme in a clinical bacteriology laboratory. METHODS: Over 24 months, 1230 diagnostic specimens, representing 0.42% of laboratory workload, were anonymised and resubmitted for analysis. Six hundred and twenty one (48.7%) of these gave positive culture results; 44 fecal and upper respiratory specimens were "spiked" (artificially inoculated) to increase the proportion of positive samples. RESULTS: Discrepancies between IQA and clinical sample results occurred in 188 cases (14.8%): 76.6% of these were in culture results, 13.3% in microscopy performance, and 10.1% in clerical recording. The culture discrepancy rate for each positive sample was lowest for wound (17.5%) and urine (18.1%) specimens, and highest for faeces (34.9%) and upper respiratory (37.7%) samples. Discrepancies in several areas responded to staff training and improvement in technical methods. CONCLUSIONS: An IQA programme of this type assesses the reproducibility of tests within a diagnostic laboratory when analysing common specimen types and organisms. It permits blind assessment of many areas of diagnostic work that are not readily amenable to other quality assurance methods, and it raises the awareness of all staff to the importance of quality in every aspect of specimen and data processing.

An evaluation of the performance of XLD, DCA, MLCB, and ABC agars as direct plating media for the isolation of Salmonella enterica from faeces.

AIMS: To compare the performance of four media, singly and in combination, as direct plating media for the isolation of Salmonella enterica from human faeces. METHODS: Two thousand four hundred and nine routine, faecal samples received by four laboratories were inoculated on to xylose lysine desoxycholate (XLD), desoxycholate citrate (DCA), mannitol lysine crystal violet brilliant green (MLCB), and alpha-beta chromogenic (ABC) agars using standardised protocols, reagents, and data collection. Isolates of presumptive salmonellae were identified using standard laboratory techniques and the results were analysed statistically. RESULTS: Direct plating recovered 46 of the 60 possible isolates of Salmonella spp recovered via enrichment broth. No isolates were recovered from direct plating that were not recovered via selenite enrichment. MLCB gave the highest isolation rate individually (84.8%) and amounts of competing flora (CF) did not affect the recognition of colonies. ABC proved highly specific, but insensitive, and isolation rates were adversely affected by any amount of CF. Isolation rates from XLD and DCA were only affected when the CF load was heavy. DCA was least specific, with only 9.01% of picks positive and greatest number of confirmatory tests. XLD and MLCB, in combination, gave the highest isolation rate. CONCLUSIONS: Where the earlier results of direct plating may be advantageous, XLD and MLCB provide the optimal combination. For non-typhi salmonellae, MLCB is the best, single direct plating medium. For routine diagnostic work, XLD is most effective.

A comparison of the performance of commercially available chromogenic agars for the isolation and presumptive identification of organisms from urine.

AIMS: To compare four media-UTI medium, BBL CHROMagar, CPS ID2, and Harlequin CLED-using a collection of fully characterised organisms and subsequent "field trial". METHODS: Seven hundred and eighty seven fully characterised isolates (730 Gram negative bacteria, 47 Gram positive bacteria, and 10 yeasts) were used to test for accuracy of organism identification. To assess isolation rates and ability to detect mixed cultures, 1435 urine samples were cultured in the three best performing chromogenic media (UTI medium, BBL CHROMagar, and CPS ID2) and CLED. RESULTS: The chromogenic agars differed in their accuracy of identification, with BBL CHROMagar performing best and Harlequin CLED performing least well. Similarly, BBL CHROMagar achieved a higher overall isolation rate than UTI medium and CPS ID2. When mixed growth was defined as greater than two organism types, BBL CHROMagar detected more mixed cultures than did UTI medium and CPS ID2, although the differences were not significant. When mixed growth was defined as greater than one organism type the increased number of mixed growths detected by BBL CHROMagar became significant, largely because of differences in enterococcal isolation rates. CONCLUSION: The use of BBL CHROMagar, UTI medium, or CPS ID2 chromogenic agar as a replacement for CLED agar would improve the detection rate of contaminated urine samples. Enhanced identification helps to distinguish different species, facilitating the monitoring of bacterial resistance in support of the national antibiotic strategy. BBL CHROMagar gave the highest overall organism recovery rates, greatest ability to detect mixed cultures, and the most accurate identification of organisms.

A comparison of the performance of cystine lactose electrolyte deficient (CLED) agar with Oxoid chromogenic urinary tract infection (CUTI) medium for the isolation and presumptive identification of organisms from urine.

AIMS: As part of the UK antimicrobial resistance strategy and action plan, the Public Health Laboratory Service (PHLS) is required to collect antibiotic susceptibility data so that resistance trends and patterns can be monitored. Most laboratories report urine Gram negative isolates, as "coliforms" according to morphological appearance, but without an acceptable identification system the antimicrobial surveillance data will be meaningless. Commercially available identification systems tend to be expensive and time consuming. Chromogenic agars, which claim to improve the detection of mixed cultures and identification of organisms from urine, have now become available and may provide a cost effective alternative. The primary aim of this study was to compare the performance of cystine lactose electrolyte deficient (CLED) agar with a chromogenic agar (Oxoid urinary tract infection medium; CUTI) in terms of isolation rates and ability to detect mixed cultures. Secondary aims were to evaluate the correlation of "presumptive" identification of isolates from chromogenic media with that of two commercial identification systems and to appraise the sensitivity of the semiquantitative loop and filter paper strip culture techniques. METHOD: One thousand, four hundred and sixty six urine samples were examined in four laboratories using the semiquantitative culture methods of 1 microl loop and filter paper strip. The degree of accuracy of organism identification was measured by comparing the presumptive identification using colony colour supplemented with simple bench tests, with identification obtained from two more complex commercial systems. RESULTS: There was no significant difference between the performance of the loop and filter paper strip methods on the CLED agar, but the CUTI agar performed significantly better than the CLED agar for the detection of significant isolates and mixed cultures. This difference was greater using the loop method. Identification of the organisms using the commercial systems gave > 99% agreement and was therefore considered suitable as a standard against which to compare the presumptive CUTI identification. Using the manufacturer's colony colour criteria in combination with a bench indole test, the CUTI medium was 99% specific for Escherichia coli, although this was reduced to 97% if the indole test was omitted. Citrobacter spp were the most commonly misidentified organisms, giving false presumptive identification as E coli. By testing oxidase activity to differentiate Pseudomonas spp and the absence of indole production to support the identification of Proteus mirabilis, the CUTI medium provided a suitable identification for 86.8% of Gram negative isolates. The remaining 13.2% would require further identification. CONCLUSION: CUTI medium improves the detection of mixed cultures, thereby improving the reliability of reporting of significant isolates when compared with CLED agar. When supplemented with simple bench tests it provides an identification system capable of speciating 86.8% of Gram negative isolates and providing a valuable cost effective mechanism for antimicrobial resistance surveillance.