Evolution over a 15-year period of clinical characteristics and outcomes of critically ill patients with community-acquired bacteremia

Molecular antimicrobial susceptibility testing in sepsis

Rapidly detecting and identifying pathogens is crucial for appropriate antimicrobial therapy in patients with sepsis. Conventional diagnostic methods have been a great asset to medicine, though they are time consuming and labor intensive. This work will enable healthcare professionals to understand the bacterial community better and enhance their diagnostic capacity by using novel molecular methods that make obtaining quicker, more precise results possible. The authors discuss and critically assess the merits and drawbacks of molecular testing and the added value of these tests, including the shift turnaround time, the implication for clinicians' decisions, gaps in knowledge, future research directions and novel insights or innovations. The field of antimicrobial molecular testing has seen several novel insights and innovations to improve the diagnosis and management of infectious diseases.

Early- and Late-Onset Bloodstream Infections in the Intensive Care Unit: A Retrospective 5-Year Study of Patients at a University Hospital in China

BACKGROUND

Limited data are available regarding the current microbiological characteristics of bloodstream infections (BSIs) in intensive care units (ICUs) in China. This retrospective study aimed to determine the epidemiology of early- and late-onset BSIs in our ICU.

METHODS

We retrospectively collected data about ICU patients with BSI from 2013 to 2017. The patients were divided into the early- and late-onset BSI groups according to if BSI occurred within or beyond 48 hours after ICU admission. Univariate and multivariate logistic regression analyses were used to assess the risk factors for infection with multidrug resistant organisms (MDROs).

RESULTS

Of 5474 ICU admissions, 486 (8.9%) patients with BSIs and with 500 microorganisms were included in this study, 246 (50.6%) of whom had early-onset BSIs. Two hundred and seventy patients were infected with MDROs. The proportion of MDRO infections was significantly higher among patients with late-onset BSIs than among those with early-onset BSIs (57.9% vs. 41.5%, P = .017). The ICU mortality rate was significantly higher in the late-onset BSI group (44.6% vs. 33.8%, P = .014) and early and appropriate antimicrobial treatment significantly improved the survival rate among patients with BSI (P < .001).

CONCLUSIONS

MDROs affected more than half of patients with BSI in the ICU. Early appropriate empirical antimicrobial therapy could improve clinical outcome of patients with BSIs.

Sepsis-A Retrospective Cohort Study of Bloodstream Infections

Bloodstream infections (BSIs) are among the leading causes of morbidity and mortality worldwide, among infectious diseases. Local knowledge of the main bacteria involved in BSIs and their associated antibiotic susceptibility patterns is essential to rationalize the empiric antimicrobial therapy. The aim of this study was to define the incidence of infection and evaluate the antimicrobial resistance profile of the main pathogens involved in BSIs. This study enrolled patients of all ages and both sexes admitted to the University Hospital “San Giovanni di Dio e Ruggi d’Aragona”, Salerno, Italy between January 2015 to December 2019. Bacterial identification and antibiotic susceptibility testing were performed with Vitek 2. A number of 3.949 positive blood cultures were included out of 24,694 total blood cultures from 2015 to 2019. Coagulase-negative staphylococci (CoNS) were identified as the main bacteria that caused BSI (17.4%), followed by Staphylococcus aureus (12.3%), Escherichia coli (10.9%), and Klebsiella pneumoniae (9.4%). Gram-positive bacteria were highly resistant to Penicillin G and Oxacillin, while Gram-negative strains to Ciprofloxacin, Cefotaxime, Ceftazidime, and Amoxicillin-clavulanate. High susceptibility to Vancomycin, Linezolid, and Daptomycin was observed among Gram-positive strains. Fosfomycin showed the best performance to treatment Gram-negative BSIs. Our study found an increase in resistance to the latest generation of antibiotics over the years. This suggests an urgent need to improve antimicrobial management programs to optimize empirical therapy in BSI.

Clinical Performance of the Novel GenMark Dx ePlex Blood Culture ID Gram-Positive Panel

Rapid identification from positive blood cultures is standard of care (SOC) in many clinical microbiology laboratories. The GenMark Dx ePlex Blood Culture Identification Gram-Positive (BCID-GP) Panel is a multiplex nucleic acid amplification assay based on competitive DNA hybridization and electrochemical detection using eSensor technology. This multicenter study compared the investigational-use-only (IUO) BCID-GP Panel to other methods of identification of 20 Gram-positive bacteria, four antimicrobial resistance genes, and both Pan Candida and Pan Gram-Negative targets that are unique to the BCID-GP Panel.

Rapid identification from positive blood cultures is standard of care (SOC) in many clinical microbiology laboratories. The GenMark Dx ePlex Blood Culture Identification Gram-Positive (BCID-GP) Panel is a multiplex nucleic acid amplification assay based on competitive DNA hybridization and electrochemical detection using eSensor technology. This multicenter study compared the investigational-use-only (IUO) BCID-GP Panel to other methods of identification of 20 Gram-positive bacteria, four antimicrobial resistance genes, and both Pan Candida and Pan Gram-Negative targets that are unique to the BCID-GP Panel. Ten microbiology laboratories throughout the United States collected residual, deidentified positive blood culture samples for analysis. Five laboratories tested both clinical and contrived samples with the BCID-GP Panel. Comparator identification methods included each laboratory’s SOC, which included matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and automated identification systems as well as targeted PCR/analytically validated real-time PCR (qPCR) with bidirectional sequencing. A total of 2,342 evaluable samples (1,777 clinical and 565 contrived) were tested with the BCID-GP Panel. The overall sample accuracy for on-panel organisms was 89% before resolution of discordant results. For pathogenic Gram-positive targets (Bacillus cereus group, Enterococcus spp., Enterococcus faecalis, Enterococcus faecium, Staphylococcus spp., Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Listeria spp., Listeria monocytogenes, Streptococcus spp., Streptococcus agalactiae, Streptococcus anginosus group, Streptococcus pneumoniae, and Streptococcus pyogenes), positive percent agreement (PPA) and negative percent agreement (NPA) ranged from 93.1% to 100% and 98.8% to 100%, respectively. For contamination rule-out targets (Bacillus subtilis group, Corynebacterium, Cutibacterium acnes, Lactobacillus, and Micrococcus), PPA and NPA ranged from 84.5% to 100% and 99.9% to 100%, respectively. Positive percent agreement and NPA for the Pan Candida and Pan Gram-Negative targets were 92.4% and 95.7% for the former and 99.9% and 99.6% for the latter. The PPAs for resistance markers were as follows: mecA, 97.2%; mecC, 100%; vanA, 96.8%; and vanB, 100%. Negative percent agreement ranged from 96.6% to 100%. In conclusion, the ePlex BCID-GP Panel compares favorably to SOC and targeted molecular methods for the identification of 20 Gram-positive pathogens and four antimicrobial resistance genes in positive blood culture bottles. This panel detects a broad range of pathogens and mixed infections with yeast and Gram-negative organisms from the same positive blood culture bottle.

Trends in the incidence and mortality of patients with community-acquired septic shock 2003-2016

PURPOSE

To evaluate the incidence and mortality of adult patients with community-acquired septic shock (CASS) and the influence of source control (SC) and other risk factors on the outcome.

MATERIAL AND METHODS

The study included patients with CASS admitted to the ICU at a university hospital (2003-2016). Multivariate analyses were performed to identify risk factors of ICU mortality.

RESULTS

A total of 625 patients were included. The incidence showed an average annual increase of 4.9% and the mortality an average annual decrease of 1.4%. The patients who required SC showed a lower mortality (20.4%) than patients who did not require SC (31.3%) (p = 0.002). However, the evolution in mortality was different: Mortality decreased in patients who did not require SC (from 56.3% to 20%; p = 0.02), but did not differ in those who required SC (from 21.4% to 27.6%; p = 0.43). In the multivariate analysis, severity at admission, age, alcoholism, cirrhosis, ARDS, neutropenia and thrombocytopenia were associated with worse outcome, whereas appropriate antibiotic treatment and adequate SC were independently associated with better survival.

CONCLUSIONS

The incidence of CASS increased and the ICU mortality decreased during the study period. The mortality was mainly due to a decrease in mortality in infections not requiring SC.

Antibiotic therapy in the critically ill - expert opinion of the Intensive Care Medicine Scientific Subcommittee of the European Society of Anaesthesiology

Antimicrobial treatment is the cornerstone of infection treatment, and the selection of appropriate antibiotic treatment for critically ill patients is challenging. Clinicians working with critically ill patients usually feel a greater obligation towards their patient than towards maintenance of the delicate ecological balance of prevalent microbiological threats and their resistance patterns. Although antibiotic overtreatment is a frequent phenomenon, patient outcomes need not be compromised when antibiotic treatment is driven by informed decision-making.At the 2016 Euro Anaesthesia Conference (London, UK), the European Society of Anaesthesia Intensive Care Scientific Subcommittee convened an expert panel on antibiotic therapy. This article summarises the main conclusions of the panel, namely the principles of antibiotic therapy that all physicians working with critically ill patients must know.

To which extent can we decrease antibiotic duration in critically ill patients?

INTRODUCTION

Inadequate empirical antibiotic therapy is associated with higher mortality in critically ill patients with severe infections. Nevertheless, prolonged duration of antibiotic treatment is also potentially harmful. Development of new infections with more resistant pathogens is one of the arguments against the administration of prolonged courses of antibiotics. Areas covered: We aim to describe the optimal duration of antimicrobial therapy in the most common infections affecting critically ill patients. A literature search was performed to identify all clinical trials, observational studies, meta-analysis, and reviews about this topic from PubMed. Expert commentary: Diverse observational studies have reported a poor outcome in critically ill patients without a documented infection who receive prolonged antibiotic therapy. We summarize the available information about the optimal duration of antimicrobial therapy in critically ill patients with severe infections including community-acquired pneumonia, intra-abdominal infections, bacteremia, meningitis and urinary-tract infections as well as the clinical consequences of short antimicrobial courses in certain severe infections. The utility of procalcitonin to reduce the duration of antibiotics is also discussed. Finally, we give clear recommendations about the length of treatment for the most common infections in critically ill patients.

Bacterial etiology of bloodstream infections and antimicrobial resistance in Dhaka, Bangladesh, 2005-2014

Background

Bloodstream infections due to bacterial pathogens are a major cause of morbidity and mortality in Bangladesh and other developing countries. In these countries, most patients are treated empirically based on their clinical symptoms. Therefore, up to date etiological data for major pathogens causing bloodstream infections may play a positive role in better healthcare management. The aim of this study was to identify the bacterial pathogens causing major bloodstream infections in Dhaka, Bangladesh and determine their antibiotic susceptibility pattern.

Methods

From January 2005 to December 2014, a total of 103,679 single bottle blood samples were collected from both hospitalized and domiciliary patients attending Dhaka hospital, icddrb, Bangladesh All the blood samples were processed for culture using a BACT/Alert blood culture machine. Further identification of bacterial pathogens and their antimicrobial susceptibility test were performed using standard microbiological procedures.

Results

Overall, 13.6% of the cultured blood samples were positive and Gram-negative (72.1%) bacteria were predominant throughout the study period. Salmonella Typhi was the most frequently isolated organism (36.9% of samples) in this study and a high percentage of those strains were multidrug-resistant (MDR). However, a decreasing trend in the S. Typhi isolation rate was observed and, noticeably, the percentage of MDR S. Typhi isolated declined sharply over the study period. An overall increase in the presence of Gram-positive bacteria was observed, but most significantly we observed the percentage of MDR Gram-positive bacteria to double over the study period. Overall, Gram positive bacteria were more resistant to most of the commonly used antibiotics than Gram-negative bacteria, but the MDR level was high in both groups.

Conclusions

This study identified the major bacterial pathogens involved with BSI in Dhaka, Bangladesh and also revealed their antibiotic susceptibility patterns. We expect our findings to help healthcare professionals to make informed decisions and provide better care for their patients. Also, we hope this study will assist researchers and policy makers to prioritize their research options to face the future challenges of infectious diseases.

Electronic supplementary material

The online version of this article (doi:10.1186/s13756-016-0162-z) contains supplementary material, which is available to authorized users.

Mortality trends in U.S. adults with septic shock, 2005-2011: a serial cross-sectional analysis of nationally-representative data

Background

We aimed to investigate mortality trends in hospitalized patients with septic shock in the US. To achieve this objective, we tested hypothesis that mortality decreased in patients identified by the code of septic shock while mortality did not change in those with septic shock identified by vasopressor use.

Methods

We conducted a serial cross-sectional analysis using Nationwide Inpatient Sample database from 2005 through 2011. First, we identified all adult patients aged ≥18 years hospitalized for septic shock by the following criteria: 1) primary ICD-9 diagnosis of infection plus procedure code for vasopressor use, 2) primary ICD-9 diagnosis of infection plus septic shock in non-primary field, and 3) primary ICD-9 diagnosis of septic shock. Second, we stratified all identified patients by record of vasopressor use. The outcome of interest was year-to-year changes in the in-hospital all-cause mortality.

Results

From 2005 to 2011, we identified 109,812 weighted hospitalizations with septic shock. Overall, there was a significant downward trend in in-hospital mortality (from 46 % in 2005 to 42 % in 2011; P_trend = 0.003); the adjusted mortality also decreased significantly (OR for comparison of 2005 with 2011, 0.98; 95 % CI, 0.96–1.00; P < 0.001). In stratified analysis, the mortality trend was not significant in the subgroup with vasopressor use (from 42 % in 2005 to 40 % in 2011; P_trend =0.57); similarly, the adjusted mortality did not change significantly (OR, 1.01; 95 % CI, 0.97–1.05; P =0.62). By contrast, there was a downward trend in mortality in the subgroup without vasopressor use (from 47 % in 2005 to 43 % in 2011; P_trend =0.002); likewise, the adjusted mortality decreased significantly (OR, 0.97; 95 % CI, 0.95–0.99; P =0.002)

Conclusions

From 2005 to 2011, we found a modest decrease in in-hospital mortality among patients identified with septic shock. However, in the subgroup with vasopressor use, we found no significant change in mortality. Our data challenge the conventional wisdom that mortality in this population has improved during the last decade.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1620-1) contains supplementary material, which is available to authorized users.

Improvement of antibiotic therapy and ICU survival in severe non-pneumococcal community-acquired pneumonia: a matched case-control study

INTRODUCTION

We aimed to compare intensive care unit mortality due to non-pneumococcal severe community-acquired pneumonia between the periods 2000-2002 and 2008-2014, and the impact of the improvement in antibiotic strategies on outcomes.

METHODS

This was a matched case-control study enrolling 144 patients with non-pneumococcal severe pneumonia: 72 patients from the 2000-2002 database (CAPUCI I group) were paired with 72 from the 2008-2014 period (CAPUCI II group), matched by the following variables: microorganism, shock at admission, invasive mechanical ventilation, immunocompromise, chronic obstructive pulmonary disease, and age over 65 years.

RESULTS

The most frequent microorganism was methicillin-susceptible Staphylococcus aureus (22.1%) followed by Legionella pneumophila and Haemophilus influenzae (each 20.7%); prevalence of shock was 59.7%, while 73.6% of patients needed invasive mechanical ventilation. Intensive care unit mortality was significantly lower in the CAPUCI II group (34.7% versus 16.7%; odds ratio (OR) 0.78, 95% confidence interval (CI) 0.64-0.95; p = 0.02). Appropriate therapy according to microorganism was 91.5% in CAPUCI I and 92.7% in CAPUCI II, while combined therapy and early antibiotic treatment were significantly higher in CAPUCI II (76.4 versus 90.3% and 37.5 versus 63.9%; p < 0.05). In the multivariate analysis, combined antibiotic therapy (OR 0.23, 95% CI 0.07-0.74) and early antibiotic treatment (OR 0.07, 95% CI 0.02-0.22) were independently associated with decreased intensive care unit mortality.

CONCLUSIONS

In non-pneumococcal severe community-acquired pneumonia , early antibiotic administration and use of combined antibiotic therapy were both associated with increased intensive care unit survival during the study period.

Decrease in mortality in severe community-acquired pneumococcal pneumonia: impact of improving antibiotic strategies (2000-2013)

OBJECTIVE

The objective of the present study was to compare antibiotic prescribing practices and survival in the ICU for patients with pneumococcal severe community-acquired pneumonia (SCAP) between 2000 and 2013.

METHODS

This was a matched case-control study of two prospectively recorded cohorts in Europe. Eighty patients from the Community-Acquired Pneumonia en la Unidad de Cuidados Intensivos (CAPUCI) II study (case group) were matched with 80 patients from CAPUCI I (control group) based on the following: shock at admission, need of mechanical ventilation, COPD, immunosuppression, and age.

RESULTS

Demographic data were comparable in the two groups. Combined antibiotic therapy increased from 66.2% to 87.5% (P < .01), and the percentage of patients receiving the first dose of antibiotic within 3 h increased from 27.5% to 70.0% (P < .01). ICU mortality was significantly lower (OR, 0.82; 95% CI, 0.68-0.98) in cases, both in the whole population and in the subgroups of patients with shock (OR, 0.67; 95% CI, 0.50-0.89) or receiving mechanical ventilation (OR, 0.73; 95% CI, 0.55-0.96). In the multivariate analysis, ICU mortality increased in patients requiring mechanical ventilation (OR, 5.23; 95% CI, 1.60-17.17) and decreased in patients receiving early antibiotic treatment (OR, 0.36; 95% CI, 0.15-0.87) and combined therapy (OR, 0.19; 95% CI, 0.07-0.51).

CONCLUSIONS

In pneumococcal SCAP, early antibiotic prescription and use of combination therapy increased. Both were associated with improved survival.

Developments for improved diagnosis of bacterial bloodstream infections

Bloodstream infections (BSIs) are associated with high mortality and increased healthcare costs. Optimal management of BSI depends on several factors including recognition of the disease, laboratory tests and treatment. Rapid and accurate identification of the etiologic agent is crucial to be able to initiate pathogen specific antibiotic therapy and decrease mortality rates. Furthermore, appropriate treatment might slow down the emergence of antibiotic resistant strains. Culture-based methods are still considered to be the "gold standard" for the detection and identification of pathogens causing BSI. Positive blood cultures are used for Gram-staining. Subsequently, positive blood culture material is subcultured on solid media, and (semi-automated) biochemical testing is performed for species identification. Finally, a complete antibiotic susceptibility profile can be provided based on cultured colonies, which allows the start of pathogen-tailored antibiotic therapy. This conventional workflow is extremely time-consuming and can take up to several days. Furthermore, fastidious and slow-growing microorganisms, as well as antibiotic pre-treated samples can lead to false-negative results. The main aim of this review is to present different strategies to improve the conventional laboratory diagnostic steps for BSI. These approaches include protein-based (MALDI-TOF mass spectrometry) and nucleic acid-based (polymerase chain reaction [PCR]) identification from subculture, blood cultures, and whole blood to decrease time to results. Pathogen enrichment and DNA isolation methods, to enable optimal pathogen DNA recovery from whole blood, are described. In addition, the use of biomarkers as patient pre-selection tools for molecular assays are discussed.

Bloodstream infections and sepsis in Greece: over-time change of epidemiology and impact of de-escalation on final outcome

BACKGROUND

Choice of empirically prescribed antimicrobials for sepsis management depends on epidemiological factors. The epidemiology of sepsis in Greece was studied in two large-periods.

METHODS

Sepsis due to bloodstream infections (BSI) from July 2006 until March 2013 was recorded in a multicenter study in 46 departments. Patients were divided into sepsis admitted in the emergencies and hospitalized in the general ward (GW) and sepsis developing after admission in the Intensive Care Unit (ICU). The primary endpoints were the changes of epidemiology and the factors related with BSIs by multidrug-resistant (MDR) pathogens; the secondary endpoint was the impact of de-escalation on antimicrobial therapy.

RESULTS

754 patients were studied; 378 from 2006-2009 and 376 from 2010-2013. Major differences were recorded between periods in the GW. They involved increase of: sepsis severity; the incidence of underlying diseases; the incidence of polymicrobial infections; the emergence of Klebsiella pneumoniae as a pathogen; and mortality. Factors independently related with BSI by MDR pathogens were chronic hemofiltration, intake of antibiotics the last three months and residence into long-term care facilities. De-escalation in BSIs by fully susceptible Gram-negatives did not affect final outcome. Similar epidemiological differences were not found in the ICU; MDR Gram-negatives predominated in both periods.

CONCLUSIONS

The epidemiology of sepsis in Greece differs in the GW and in the ICU. De-escalation in the GW is a safe strategy.

[Severe infections : causes and management of sepsis]

The sepsis syndrome has only recently been defined as a clinical syndrome but despite its unspecific definition it has evolved rapidly into an important concept. Although specific therapeutic interventions targeting the inflammatory pathway have not yet been effective in treating sepsis, a better understanding of mechanisms leading to organ dysfunction has led to better management of patients with sepsis. Clinical signs of systemic inflammatory response syndrome (SIRS) or sepsis are hallmarks for the definition of severe infections. Current guidelines are presented for the management of a number of severe infectious syndromes.

Diabetes mellitus and community-acquired bloodstream infections in the critically ill

INTRODUCTION

Community-acquired bloodstream infections have not been studied related to diabetes mellitus in the critically ill.

HYPOTHESIS

We hypothesized that the diagnosis of diabetes mellitus and poor chronic glycemic control would increase the risk of community-acquired bloodstream infections (CA-BSIs) in the critically ill.

METHODS

We performed an observational cohort study between 1998 and 2007 in 2 teaching hospitals in Boston, Massachusetts. We studied 2551 patients 18 years or older, who received critical care within 48 hours of admission and had blood cultures obtained within 48 hours of admission. The exposure of interest was diabetes mellitus defined by International Classification of Diseases, Ninth Revision, Clinical Modification, code 250.xx in outpatient or inpatient records. The primary end point was CA-BSI (<48 hours of hospital admission). Patients with a single coagulase-negative Staphylococcus positive blood culture were not considered to have bloodstream infection. Associations between diabetes groups and bloodstream infection were estimated by bivariable and multivariable logistic regression models. Subanalyses included evaluation of the association between hemoglobin A1c (HbA1c) and bloodstream infection, diabetes and risk of sepsis, and the proportion of the association between diabetes and CA-BSI that was mediated by acute glycemic control.

RESULTS

Diabetes is a predictor of CA-BSI. After adjustment for age, sex, race, patient type (medical vs surgical), and acute organ failure, the risk of bloodstream infection was significantly higher in patients with diabetes (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.10-1.82; P = .006) relative to patients without diabetes. The adjusted risk of bloodstream infection was increased in patients with HbA1c of 6.5% or higher (OR, 1.31; 95% CI, 1.04-1.65; P = .02) relative to patients with HbA1c less than 6.5%. Furthermore, the adjusted risk of sepsis was significantly higher in patients with diabetes (OR, 1.26; 95% CI, 1.04-1.54; P = .02) relative to patients without diabetes. Maximum glucose did not significantly mediate the relationship between diabetes mellitus diagnosis and CA-BSI.

CONCLUSIONS

A diagnosis of diabetes mellitus and HbA1c of 6.5% or higher is associated with the risk of CA-BSI in the critically ill.

The complex pathogenesis of bacteremia: from antimicrobial clearance mechanisms to the genetic background of the host

Bacteremia develops when bacteria manage to escape the host immune mechanisms or when the otherwise well-orchestrated immune response fails to control bacterial spread due to inherent or acquired immune defects that are associated with susceptibility to infection. The pathogenesis of bacteremia has some characteristic features that are influenced by the genetic signature of the host. In this review, the host defense mechanisms that help prevent bacteremia will be described and the populations who are at risk because of congenital or acquired deficiencies in such mechanisms will be defined. A special mention will be made to novel insights regarding host immune defense against the most commonly isolated organisms from patients with community-acquired bloodstream infections.

[Initial patient assessment of infectious diseases and diagnostic steps with fever]

The initial assessment of patients with infectious diseases is challenging because of the extremely broad differential diagnosis as well as different host pathogen interactions influenced by a different immune status. The formal initial assessment, including the present and past medical history, thorough physical examination, clinical first impressions as well as routine laboratory analyses, is the basis of every preliminary diagnosis. Specific chief complaints have to be recognized in order to narrow down the differential diagnosis. In cases of life-threatening illnesses, such as septicemia, endocarditis, bacterial meningitis and severe pneumonia, the first diagnostic and therapeutic steps should be performed in a rapid sequence: bacterial blood samples, sputum and/or liquor samples are required and the initial antibiotic therapy has to be chosen empirically as the relevant bacterial spectrum related to the suspected illness must be covered. In less urgent cases it is recommended that a multi-step diagnostic approach be carried out which takes the differential diagnosis into account and prioritizes the probabilities. In the latter situation antibiotic treatment should be delayed to diagnose the infection correctly. Importantly, atypical courses must necessitate careful and critical reassessment of the diagnosis.