Commercial bacterial and fungal broad-range PCR (Micro-Dx™) used on culture-negative specimens from normally sterile sites: diagnostic value and implications for antimicrobial treatment

The aim of this study was to evaluate the clinical value of partial 16S/18S rRNA gene sequencing with the commercial kit Micro-Dx™ used with the SelectNA™plus instrument on culture-negative samples. A retrospective study of microbiological and clinical data from a 2.5-year period was performed. Assessment of the clinical relevance of the 16S/18S rRNA gene sequencing results was based on evaluation of the results in the clinical context and changes in antimicrobial therapy. Included were 529 samples from 223 patients, representing 251 episodes. In 191 samples (36.1%), bacterial/fungal DNA was detected. Positive results were judged clinically relevant in 79 (31.5%) episodes. Antimicrobial treatment was adjusted according to the 16S/18S rRNA gene sequence analysis result in 42 (16.7%) episodes. The results from 16S/18S rRNA gene sequence analysis were highly clinically relevant. These findings support the use of this analysis in a routine setting.

Associations between blood cultures after surgery for colorectal cancer and long-term oncological outcomes

BACKGROUND

Systemic inflammation following curative surgery for colorectal cancer may be associated with increased risk of recurrence. [Correction added on 29 November 2019, after first online publication: text amended for accuracy.] This study investigated whether a clinically suspected infection, for which blood cultures were sent within 30 days after surgery for colorectal cancer, was associated with long-term oncological outcomes.

METHODS

This register-based national cohort study included all Danish residents undergoing surgery with curative intent for colorectal cancer between January 2003 and December 2013. Patients who developed recurrence or died within 180 days after surgery were not included. Associations between blood cultures taken within 30 days after primary surgery and overall survival, disease-free survival and recurrence-free survival were analysed using Cox regression models adjusted for relevant clinical confounders, including demographic data, cancer stage, co-morbidity, blood transfusion, postoperative complications and adjuvant chemotherapy.

RESULTS

The study included 21 349 patients, of whom 3390 (15·9 per cent) had blood cultures taken within 30 days after surgery. Median follow-up was 5·6 years. Patients who had blood cultures taken had an increased risk of all-cause mortality (hazard ratio (HR) 1·27, 95 per cent c.i. 1·20 to 1·35; P < 0·001), poorer disease-free survival (HR 1·22, 1·16 to 1·29; P < 0·001) and higher risk of recurrence (HR 1·15, 1·07 to 1·23; P < 0·001) than patients who did not have blood cultures taken.

CONCLUSION

A clinically suspected infection requiring blood cultures within 30 days of surgery for colorectal cancer was associated with poorer oncological outcomes.

Pseudomonas aeruginosa and risk of death and exacerbations in patients with chronic obstructive pulmonary disease: an observational cohort study of 22 053 patients

OBJECTIVES

The role of Pseudomonas aeruginosa in the long-term prognosis of chronic obstructive pulmonary disease (COPD) is unknown. The purpose of this study was to determine whether P. aeruginosa is associated with increased risk of exacerbations or death in patients with COPD.

METHODS

This is a multiregional epidemiological study based on complete data on COPD outpatients between 1 January 2010 and 31 October 2017 and corresponding microbiology and national register data. Time-dependent Cox proportional hazards models and propensity matching was used to estimate hospitalization-demanding exacerbations and death after 2 years, separately and in combination.

RESULTS

A total of 22 053 COPD outpatients were followed for a median of 1082 days (interquartile-range: 427-1862). P. aeruginosa was present in 905 (4.1%) patients. During 730 days of follow-up, P. aeruginosa strongly and independently predicted an increased risk of hospitalization for exacerbation or all-cause death (HR 2.8, 95%CI 2.2-3.6; p <0.0001) and all-cause death (HR 2.7, 95%CI 2.3-3.4; p <0.0001) in analyses adjusted for known and suspected confounders. The signal remained unchanged in unadjusted analyses as well as propensity-matched subgroup analyses. Among patients 'ever colonized' with P. aeruginosa, the incidence of hospital-demanding exacerbations doubled after the time of the first colonization.

CONCLUSIONS

COPD patients in whom P. aeruginosa can be cultured from the airways had a markedly increased risk of exacerbations and death. It is still not clear whether this risk can be reduced by offering patients targeted antipseudomonal antibiotics. A randomized trial is currently recruiting patients to clarify this (ClinicalTrials.gov: NCT03262142).

To test or not to test? Laboratory support for the diagnosis of Lyme borreliosis: a position paper of ESGBOR, the ESCMID study group for Lyme borreliosis

BACKGROUND

Lyme borreliosis (LB) is a tick-borne infection caused by Borrelia burgdorferi sensu lato. The most frequent clinical manifestations are erythema migrans and Lyme neuroborreliosis. Currently, a large volume of diagnostic testing for LB is reported, whereas the incidence of clinically relevant disease manifestations is low. This indicates overuse of diagnostic testing for LB with implications for patient care and cost-effective health management.

AIM

The recommendations provided in this review are intended to support both the clinical diagnosis and initiatives for a more rational use of laboratory testing in patients with clinically suspected LB.

SOURCES

This is a narrative review combining various aspects of the clinical and laboratory diagnosis with an educational purpose. The literature search was based on existing systematic reviews, national and international guidelines and supplemented with specific citations.

IMPLICATIONS

The main recommendations according to current European case definitions for LB are as follows. Typical erythema migrans should be diagnosed clinically and does not require laboratory testing. The diagnosis of Lyme neuroborreliosis requires laboratory investigation of the spinal fluid including intrathecal antibody production, and the remaining disease manifestations require testing for serum antibodies to B. burgdorferi. Testing individuals with non-specific subjective symptoms is not recommended, because of a low positive predictive value.

The diagnostic accuracy of serological tests for Lyme borreliosis in Europe: a systematic review and meta-analysis

Background

Interpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe.

Methods

We searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy.

Results

Seventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50 % (95 % CI 40 % to 61 %); neuroborreliosis 77 % (95 % CI 67 % to 85 %); acrodermatitis chronica atrophicans 97 % (95 % CI 94 % to 99 %); unspecified Lyme borreliosis 73 % (95 % CI 53 % to 87 %). Specificity was around 95 % in studies with healthy controls, but around 80 % in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches.

Conclusions

The observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

Improving national surveillance of Lyme neuroborreliosis in Denmark through electronic reporting of specific antibody index testing from 2010 to 2012

Our aim was to evaluate the results of automated surveillance of Lyme neuroborreliosis (LNB) in Denmark using the national microbiology database (MiBa), and to describe the epidemiology of laboratory-confirmed LNB at a national level. MiBa-based surveillance includes electronic transfer of laboratory results, in contrast to the statutory surveillance based on manually processed notifications. Antibody index (AI) testing is the recommend laboratory test to support the diagnosis of LNB in Denmark. In the period from 2010 to 2012, 217 clinical cases of LNB were notified to the statutory surveillance system, while 533 cases were reported AI positive by the MiBa system. Thirty-five unconfirmed cases (29 AI-negative and 6 not tested) were notified, but not captured by MiBa. Using MiBa, the number of reported cases was increased almost 2.5 times. Furthermore, the reporting was timelier (median lag time: 6 vs 58 days). Average annual incidence of AI-confirmed LNB in Denmark was 3.2/100,000 population and incidences stratified by municipality ranged from none to above 10/100,000. This is the first study reporting nationwide incidence of LNB using objective laboratory criteria. Laboratory-based surveillance with electronic data-transfer was more accurate, complete and timely compared to the surveillance based on manually processed notifications. We propose using AI test results for LNB surveillance instead of clinical reporting.

Does Alzheimer's disease with early onset progress faster than with late onset? A case-control study of clinical progression and cerebrospinal fluid biomarkers

BACKGROUND

Early-onset Alzheimer's disease (EOAD) is generally thought to have a more rapid course compared to late-onset Alzheimer's disease (LOAD). The faster progression of EOAD observed in some studies has also been thought to correlate with cerebrospinal fluid (CSF) biomarkers. Our clinical experience has not been suggestive of any difference in disease progression; therefore, we decided to investigate whether differences in clinical progression and CSF biomarkers between EOAD and LOAD could be demonstrated.

METHODS

Case-control study with 42 patients, 21 EOAD and 21 matched LOAD patients. Rates of progression were calculated and these, as well as CSF biomarker levels, were statistically compared.

RESULTS

There were no statistically significant differences in clinical progression between the EOAD group and the LOAD group. There was no significant difference in the absolute values of CSF biomarkers, but a tendency towards lower levels of β-amyloid in patients with EOAD was observed.

CONCLUSIONS

Our findings did not converge with results from the majority of previous studies, which have been suggestive of a faster clinical progression in EOAD. Possibly, the very strict algorithm by which our patients were matched explains our findings. However, the findings should be repeated in a larger study population.

Coronaviruses in brain tissue from patients with multiple sclerosis

Brain tissue from 25 patients with clinically definite multiple sclerosis (MS) and as controls brain tissue from 36 patients without neurological disease was tested for the presence of human coronaviral RNA. Four PCR assays with primers specific for N-protein of human coronavirus strain 229E and three PCR assays with primers specific for the nucleocapsid protein of human coronavirus strain OC43 were performed. Sporadic positive PCR assays were observed in both patients and controls in some of the PCR assays. However, these results were not reproducible and there was no difference in the proportion of positive signals from the MS patients compared to controls. Evidence for a chronic infection with the human coronaviruses strain 229E or OC43 in brain tissue from patients with MS or controls has not been found in this study.

Antagonism between penicillin and erythromycin against Streptococcus pneumoniae in vitro and in vivo

The combination of beta-lactam antibiotics and macrolides is often recommended for the initial empirical treatment of acute pneumonia in order to obtain activity against the most important pathogens. Theoretically, this combination may be inexpedient, as the bacteriostatic agent may antagonize the effect of the bactericidal agent. In this study, the possible interaction between penicillin and erythromycin was investigated in vitro and in vivo against four clinical isolates of Streptococcus pneumoniae with MICs of penicillin ranging from 0.016 to 0.5 mg/L and of erythromycin from 0. 25 to >128 mg/L. In vitro time-kill curves were generated with clinically relevant concentrations of penicillin (10 mg/L) and erythromycin (1 mg/L), either individually or in combination. Antagonism between penicillin and erythromycin was observed for the four isolates. In vivo interaction was investigated in the mouse peritonitis model. After intraperitoneal inoculation, penicillin and erythromycin were given either individually or in combination. For two of the four isolates, mortality was significantly higher in the groups treated with the combination of penicillin and erythromycin than in the groups treated with penicillin alone [32/36 (86%) vs. 3/12 (25%), P<0.05; and 24/36 (67%) vs. 3/12 (25%), P<0.05, respectively]. Using the mouse peritonitis model, in vivo time-kill curves showed that there was antagonism between erythromycin and penicillin for the examined isolate. The antagonism demonstrated in vitro and in vivo between penicillin and erythromycin suggests that ss-lactam antibiotics and macrolides should not be administered together unless pneumococcal infection is ruled out.

Coronaviruses in spinal fluid of patients with acute monosymptomatic optic neuritis

Acute monosymptomatic optic neuritis (AMON) may be an initial symptom of multiple sclerosis (MS). Coronaviruses have been implicated in the etiology of MS. The objective of the present study was to look for coronaviral RNA in AMON, which could be present in the initial stages of the development of MS.

MATERIAL AND METHODS

Spinal fluids from 37 patients with AMON and 15 surgical control patients with protrusion of the intervertebral disk were assayed with a nested multiplex polymerase chain reaction with primers specific for human coronaviruses strain (HCV) 229E and OC43.

RESULTS

Four patients and 1 control were positive for HCV-229E. No evidence of HCV-OC43 was found. The frequency of positive samples was low and there was no statistical difference between AMON and controls.

CONCLUSION

This study does not provide evidence for an etiological role of human coronaviruses in acute monosymptomatic optic neuritis.

Absence of entero- and cardioviral RNA in multiple sclerosis brain tissue

OBJECTIVES

Epidemiological evidence suggests that an infectious agent may be involved in the pathogenesis of multiple sclerosis (MS). Picornaviruses are possible candidates for an etiological agent, because of their neurotropic properties and ability to cause chronic infections.

MATERIALS AND METHODS

Autopsy brain tissue from 25 patients with clinically definite MS and 33 control patients without inflammatory neurological disease was tested with reverse transcription PCR specific for enteroviruses and cardioviruses.

RESULTS

All specimens were found negative.

CONCLUSION

These results do not support the theory of a persisting entero- or cardioviral infection as the cause of Ms as we found no evidence of the presence of entero- or cardioviral genomes in the brains from MS patients.

Pulmonary nodules due to Corynebacterium ulcerans

A 53 year old male with symptoms of coughing for 6 months presented with bilateral multiple pulmonary nodules suggestive of metastatic disease. By surgical resection 4 out of 6 nodules were removed. Histopathological examination showed granulomatous necrotizing inflammation with growth of Corynebacterium ulcerans, which did not produce diphtheria toxin. The patient was treated with penicillin for 1 week. Follow-up for 2 yrs showed no sign of recurrence.

Pulmonary nodules due to Corynebacterium ulcerans

A 53 year old male with symptoms of coughing for 6 months presented with bilateral multiple pulmonary nodules suggestive of metastatic disease. By surgical resection 4 out of 6 nodules were removed. Histopathological examination showed granulomatous necrotizing inflammation with growth of Corynebacterium ulcerans, which did not produce diphtheria toxin. The patient was treated with penicillin for 1 week. Follow-up for 2 yrs showed no sign of recurrence.

Polymerase chain reaction as a rapid diagnostic assay for cytomegalovirus infection in renal transplant patients

The aim of this study was to apply a polymerase chain reaction for diagnosis of CMV infection and determine its clinical value in renal transplant recipients. We have applied the PCR to urine and blood specimens collected from 27 renal transplant recipients as well as blood from 49 normal blood donors. Ten of twenty-seven patients, compared to 3 of 49 normal blood donors, had CMV-DNA present in one or more samples. Six of the ten CMV-DNA-positive patients had positive CMV serology, and 3 of the 10 had severe clinical symptoms of active CMV infection. In four additional patients with positive CMV serology - but without clinical signs of active CMV infection - no CMV-DNA could be detected by the PCR. In the three patients with severe symptoms, PCR could detect CMV-DNA before serology became positive, and in one of these three patients, serology remained negative despite the patient's death from clinically obvious CMV pneumonia. PCR thus appears capable of detecting active CMV infection at a time when CMV serology is inconclusive, but cannot substitute for serology as the only routine analysis since a transient viraemia might be missed. However, in immunosuppressed patients with severe CMV infection, PCR could provide an early diagnosis, enabling the clinician to implement early specific treatment.

[Ampicillin-resistant Haemophilus influenzae. Prevalence in isolates from Danish children]

The prevalence of ampicillin-resistance was assessed among a total of 2766 strains of H. influenzae isolated from lower respiratory tract secretions, middle ear secretions, spinal fluid specimens, and blood cultures from children 0-15 years of age tested in two separate counties in Denmark during the period from 1986 to May, 1993. All strains were tested for susceptibility to ampicillin with disc or tablet diffusion technique and strains were examined for beta-lactamase production with a chromogenic cephalosporinase test. In the county of Northern Jutland the rate of beta-lactamase production in non-encapsulated H. influenzae was 2.5% in 1986 rising to 9.3% in 1993. The rate of beta-lactamase production in H. influenzae type b was 4.1% without any rise. In the county of Copenhagen the rate of beta-lactamase production in non-encapsulated H. influenzae rose from 6.3% in 1986 to 10.6% in 1992. In 1993 a further increase to 20.7% was noticed. This year the number of specimens sent to the laboratory and the number of H. influenzae isolated were lower compared to previous years. Thus a different selection of patients may explain the increase in the rate of beta-lactamase production in 1993. The rate of beta-lactamase production in H. influenzae type b was 8.5%. No strains were resistant to ampicillin in diffusion test other than the beta-lactamase producers.

[Respiratory syncytial virus infection. A frequent child disease in Denmark with annual outbreaks]

Infection with respiratory syncytial virus (RSV) is an important cause of illness in infants often leading to hospital admission during the winter months. Diagnosis of RSV by direct detection of virus antigen has been implemented in a number of departments of clinical microbiology, and on this background a descriptive study of the seasonal incidence, sex and age distribution of RSV in two Danish counties was undertaken. A total of 5533 clinical episodes of respiratory infection were registered from October 1988 to September 1992 in the two counties and 1421 (26%) were positive for RSV. The incidence of hospital admission for RSV infection was 14 per 1000 below three years of age in Copenhagen County in the winter season 1991-1992. The seasonal peak of RSV infection was postponed about one month in Northern Jutland as compared to the capital area. Only 10 episodes (three positive) were from primary care, the remainder from hospitals and other institutions. RSV-testing was rarely requested in general practice. The study confirmed the importance of RSV infection in young children admitted with lower respiratory tract infection. We recommend the establishment of a surveillance system incorporating the local departments of clinical microbiology for warning of the yearly epidemics during which RSV infections may also be a risk outside the paediatric age span.

Computerized surveillance in clinical microbiology with time series analysis

An automatic surveillance system to detect changes in the incidences of microorganisms diagnosed in the department of clinical microbiology has been developed. The program is incorporated into the laboratory computer system and gives a weekly list of microorganisms whose isolation rates compared with those of a previous period exceed a chosen limit. The system uses time series analysis with moving weighted averages, and the detection limit is based on the distribution of the residuals. Output from the system included information about potential outbreaks of gastroenteritis, nosocomial infection with Corynebacterium jeikeium, and a seasonal epidemic of respiratory syncytial virus. The system also listed organisms not commonly isolated in the laboratory and detected incorrect reports. We conclude that continuous surveillance of laboratory data with time series analysis is a valuable tool for epidemiologic surveillance and quality control. Large quantities of data may be screened.

[Reproducibility of a rapid test for HIV antibody]

This study evaluated three rapid test kits for HIV antibody detection. Thirty consecutive blood specimens from the infectious diseases outpatient clinic were examined by three house officers who tested each specimen twice in a blind and randomized experiment. HIV-Chek (Du Pont) and HIV-1/HIV-2 TestPack (Abbott) were easy to handle and gave good intra- and interobserver agreement and good agreement with routine ELISA. Recombigen (BioScience) was difficult to interpret and gave poorer intra- and inter-observer variation. We suggest that HIV-Chek and TestPack can be used for assessment of patients' HIV antibody status in emergency circumstances with only minimal instruction of the staff.

[Psychogenic polydipsia: pronounced cerebral edema after exaggerated consumption of boiled water]

A case of psychogenic polydipsia is presented. A 40 year old female was brought to the emergency room after a sudden seizure at home. The patient had spontaneous eye opening, was making incomprehensible sounds and had abnormal and agitated flexion of the limbs. Severe cerebral edema was seen on the computed tomogram. The patient was found to have hypotonic polyuria and hyponatremia. Two months previously, the patient had stopped taking bromazepam (a benzodiazepine) and on the advice of a neighbour had taken plenty of water to avoid withdrawal symptoms. The diagnosis and therapy are discussed.