Rapid Bacterial Diagnostics and Their Effect on Patient Treatment and Outcome

The aim of this thesis is to validate new rapid diagnostic tests and to investigate if improving microbiological diagnostics influences patient outcome and management. Therefore a short introduction in the underlying clinical syndrome is warranted. Sepsis is a major complication of infection with a high morbidity and mortality. Table 1 shows the diagnostic criteria of sepsis and severe sepsis (20). In their review Angus and Wax (3) cited several studies that reported mortality rates varying from 20 to 52%. From a point prevalence survey of Van Gestel et al. (66) it was calculated that the annual number of admissions for severe sepsis in Dutch ICUs was 8643 ± 929 cases/year, which represents 0.054% of the Dutch population, 0.61% of hospital admissions and 11% of ICU admissions. In 2008 Surviving Sepsis Campaign published international guidelines for management of severe sepsis and septic shock (20). They used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system for assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. Their key recommendations, relevant for microbiologists and clinicians alike were among others: obtain blood cultures before starting antibiotic therapy (1C); administer broad-spectrum antibiotic therapy within 1 h of diagnosis of severe sepsis with or without septic shock (1B,1D) ; reassess antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C)

Does electronic clinical microbiology results reporting influence medical decision making: a pre- and post-interview study of medical specialists

Background: Clinicians view the accuracy of test results and the turnaround time as the two most important service aspects of the clinical microbiology laboratory. Because of the time needed for the culturing of infectious agents, final hardcopy culture results will often be available too late to have a significant impact on early antimicrobial therapy decisions, vital in infectious disease management. The clinical microbiologist therefore reports to the clinician clinically relevant preliminary results at any moment during the diagnostic process, mostly by telephone. Telephone reporting is error prone, however. Electronic reporting of culture results instead of reporting on paper may shorten the turnaround time and may ensure correct communication of results. The purpose of this study was to assess the impact of the implementation of electronic reporting of final microbiology results on medical decision making. Methods. In a pre- and post-interview study using a semi-structured design we asked medical specialists in our hospital about their use and appreciation of clinical microbiology results reporting before and after the implementation of an electronic reporting system. Results: Electronic reporting was highly appreciated by all interviewed clinicians. Major advantages were reduction of hardcopy handling and the possibility to review results in relation to other patient data. Use and meaning of microbiology reports differ significantly between medical specialties. Most clinicians need preliminary results for therapy decisions quickly. Therefore, after the implementation of electronic reporting, telephone consultation between clinician and microbiologist remained the key means of communication. Conclusions: Overall, electronic reporting increased the workflow efficiency of the medical specialists, but did not have an impact on their decision-making

Livestock-associated methicillin-resistant Staphylococcus aureus epidemiology, genetic diversity, and clinical characteristics in an urban region

ObjectivesWhile Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA), defined as CC398, is a well-known pathogen among those working with livestock, there are indications that LA-MRSA prevalence among the general population is increasing. However, the clinical impact in urban areas remains unknown. The aim of this study was to assess the genetic epidemiology and clinical characteristics of LA-MRSA in an urban area with a limited livestock population.MethodsIn this retrospective study, we evaluated LA-MRSA strains that were collected between 2014 and 2018 from patients who received clinical care in a single urban area in Netherlands. Patient files were assessed for livestock exposure data, clinical findings, and contact tracing information. Next-generation sequencing (NGS) analysis in combination with wgMLST was conducted to assess genetic diversity and relatedness and to detect virulence and resistance genes.ResultsLA-MRSA strains were cultured from 81 patients, comprising 12% of all the MRSA strains found in seven study laboratories between 2014 and 2018. No livestock link was found in 76% of patients (n = 61), and 28% of patients (n = 23) had an infection, mostly of the skin or soft tissue. Contact tracing had been initiated in 14 cases, leading to the identification of two hospital transmissions: a cluster of 9 cases and one of 2 cases. NGS data were available for 91% (n = 75) of the patients. wgMLST confirmed the clusters detected via contact tracing (n = 2) and identified 5 additional clusters without a known epidemiological link. Relevant resistance and virulence findings included the PVL virulence gene (3 isolates) and tetracycline resistance (79 isolates).ConclusionLA-MRSA may cause a relevant burden of disease in urban areas. Surprisingly, most infections in the present study occurred in the absence of a livestock link, suggesting inter-human transmission. These findings and the presence of PVL and other immune evasive complex virulence genes warrant future surveillance and preventative measures

Frequency of Microbiologically Correct Antibiotic Therapy Increased by Infectious Disease Consultations and Microbiological Results

In a prospective observational study of bacteremic patients we ascertained the influence of different parts of culture results on the correctness of empirical antibiotic therapy. Ninety-three bacteremic patients requiring antibiotic treatment were included. Patients who had consultations with an infectious disease consultation service before they became bacteremic received microbiologically correct empirical antibiotic therapy more often than those who did not have such consultations (75% versus 53%; P = 0.03). As a direct result of Gram staining, 92% of all patients received microbiologically correct antibiotic therapy

Frequency of microbiologically correct antibiotic therapy increased by infectious disease consultations and microbiological results

In a prospective observational study of bacteremic patients we ascertained the influence of different parts of culture results on the correctness of empirical antibiotic therapy. Ninety-three bacteremic patients requiring antibiotic treatment were included. Patients who had consultations with an infectious disease consultation service before they became bacteremic received microbiologically correct empirical antibiotic therapy more often than those who did not have such consultati

Immediate Incubation of Blood Cultures Outside Routine Laboratory Hours of Operation Accelerates Antibiotic Switching

The aim of this prospective randomized controlled clinical trial was to assess the impact of immediate incubation of blood cultures delivered to the laboratory outside its hours of operation on turnaround times, antibiotic prescription practices, and patient outcomes. A continuously monitoring blood culture incubator was placed outside the laboratory, which was switched on (intervention arm) and off (control arm) in a randomized manner. Included were new bacteremia episodes of patients older than 18 years. During the 30-week study period, the first positive blood culture specimen of an episode had to be brought to the laboratory outside its hours of operation. The median time from specimen collection until growth detection was reduced by 10.1 h in the intervention arm (P < 0.001). For 46 of 66 (70%) episodes in the intervention arm and for 51 of 85 (60%) episodes in the control arm, the antibiotic regimen was changed (not significant). The median time until the first change in the antibiotic regimen was 42.8 h in the intervention arm and 64.0 h in the control arm (P, 0.024). There was no difference in length of stay or hospital mortality. Immediate incubation of blood cultures outside laboratory hours reduces turnaround times and accelerates antibiotic switching

Needle-to-Incubator Transport Time: Logistic Factors Influencing Transport Time for Blood Culture Specimens

The maximum recommended transport time for blood cultures is 4 h [L. S. Garcia (ed.), 2007 Update: Clinical Microbiology Procedures Handbook, 2nd ed., 2007]. In a previous study, we found that the average transport time was 10 h. In this cohort study, we measured transport times for blood cultures in a larger sample and identified predictors for transport times. A total of 4,322 blood cultures from 1,313 patients were included. The median transport time was 3.5 h, with 47% of cultures exceeding the recommended 4 h. Off-site location and type of clinical specialty were the most important predictors of long transport times. Cultures collected during weekend days or on wards at the largest distances from the laboratory were also associated with long transport times