Background:Intravenous immunoglobulins (IVIGs) have been suggested as an adjunctive treatment in streptococcal toxic shock syndrome (STSS), but there are no conclusive trials. In southern Sweden, IVIG is routinely used in certain hospitals but not others. We hypothesized that this would resemble a natural experiment, and we aimed to evaluate the effect of IVIG in patients with STSS. Method:We conducted a population-based retrospective cohort study on STSS cases in southern Sweden from 2017 to 2024. The main exposure was any IVIG treatment, and the primary outcome was 30-day mortality. Cox regression was used, adjusted for lactate, Sequential Organ Failure Assessment score, Charlson Comorbidity Index, and concurrent clindamycin treatment. We modeled IVIG as a time-dependent variable to address immortal time bias. Results:In total, 106 patients fulfilled STSS criteria, of which 56 (53%) were treated with IVIG. Despite geographic differences, the IVIG group was younger and had fewer comorbidities but higher disease severity at baseline. Crude analysis suggested lower mortality in the IVIG group (hazard ratio, 0.69; 95% CI, .34-1.41). However, after adjusting for covariates and accounting for immortal time bias, the hazard ratio was estimated at 1.69 (95% CI, .66-4.30). Conclusions:Although our study included a large population of patients with STSS, our results were inconclusive regarding the effect of IVIG on 30-day mortality. This study highlights the risk of bias in observational studies in rare conditions. Prospective interventional studies are needed to determine the efficacy of IVIG in patients with STSS.

Early administration of beta-lactam antibiotics is a crucial part in the treatment of sepsis and septic shock. Beta-lactams demonstrate time-dependent killing and therefore it is important to optimize the time above the minimal inhibitory concentration (MIC). An extra dose is recommended in threatening/suspected/confirmed septic shock. This study aimed to examine whether patients with suspected sepsis achieved adequate concentrations after the initial dose. A prospective observational study was conducted in patients with suspected sepsis at the emergency department, started on cefotaxime, piperacillin-tazobactam or meropenem. The primary endpoint was defined as trough serum concentration above EUCAST clinical breakpoints for Enterobacterales spp., during the whole dosing interval, 100

PURPOSE:Despite advances in medical care, bacterial meningitis still poses a considerable health issue from a global perspective. An ageing population and increasing development and use of vaccines are likely to affect the incidence and aetiology. The aim of this study was to describe the incidence and aetiology of community-acquired bacterial meningitis (CABM) in our setting, as well as the serotypes of Streptococcus pneumoniae and Neisseria meningitidis causing CABM, in relation to available vaccines. METHOD:Patients of all ages with CABM in southern Sweden 2013-2023 were included. Patients were identified through records of cerebrospinal fluid tests from the Department of Clinical Microbiology, and through International Classification of Diseases 10 codes for bacterial meningitis. Age-standardised incidence rates were calculated based on the European Standard Population 2013. RESULTS:During the study period, 244 episodes of CABM in 238 individuals were identified. Definitive aetiology could be established in 93% of episodes. Mean incidence rate was 1.63 per 100,000 person-years, with a trend of declining incidence during the study period. Streptococcus pneumoniae was the most common pathogen, accounting for 46.7% of episodes. 63.6% of the episodes of pneumococcal meningitis were caused by serotypes included in current vaccines. CONCLUSION:Pneumococcal meningitis is the primary driver of incidence and trends of all-cause community-acquired bacterial meningitis in southern Sweden. Further studies are warranted to investigate how vaccination could influence both disease incidence and shifts in serotype distribution, while also identifying optimal patient populations for targeted interventions.

OBJECTIVES:Short time to positivity (TTP) has been proposed as a prognostic indicator in bloodstream infection (BSI) but results have been conflicting. The aim of this study was to explore the association between TTP and disease severity, using non-linear models. METHODS:This population-based retrospective study included all blood cultures in southern Sweden from 2021 to 2023. Using healthcare databases, BSI episodes were linked to information regarding prespecified disease severity markers at the time of culture (laboratory values and vital signs) as well as patient outcomes (intensive care admission and all-cause mortality at 30 days). The associations between TTP vs. disease severity were explored using non-linear regression models. RESULTS:The study included 12 585 unique BSI episodes, with a median (interquartile range) TTP of 12.1 (9.7-17.7) hours, and an overall 30-day mortality rate of 14.4%. Non-linear regression models indicated a higher mortality rate with shorter TTP, with a mortality rate of 20% at a TTP of 6 hours, and 30% at a TTP of 3 hours. In Enterobacterales, beta-haemolytic streptococci, Streptococcus pneumoniae, Staphylococcus aureus, as well as in polymicrobial findings, regression models indicated that shorter TTP was associated with a risk of >30% of intensive care admission or mortality, as compared with an overall rate of 18.2%. Shorter TTP was also associated with laboratory values and vital signs. For lactate, with an overall median value of 1.9 mmol/L, the model indicated a value of 3 mmol/L at a TTP of 8 hours, and at 4 mmol/L at a TTP of 4 hours. All associations with disease severity markers and outcomes were non-linear. DISCUSSION:TTP is an indicator of disease severity and prognosis in BSIs. The exponential association provides a biologically plausible explanation for previously conflicting results. Future studies should focus on determining the clinical utility of TTP.

Abstract Background Community-acquired pneumonia (CAP) was one of the most common causes of death in the European Union in 2017. Severity and mortality of CAP increase with age and an aging European population will require increased planning for prevention, control, and management of CAP. The purpose of this study was to provide an updated population-based estimate of the incidence of CAP requiring hospitalization in Northern Europe. Method We conducted a retrospective cohort study estimating the population-based incidence of CAP requiring hospitalization. Adults residing in Southern Sweden admitted between September 2016 and September 2018 with radiographically confirmed CAP and a primary discharge diagnosis consistent with pneumonia were identified by retrospective medical chart review. Incidence rates were stratified by age and sex. Results We identified 1,575 episodes of CAP in 1,471 unique individuals, accounting for 45% of the total eligible patient population. The crude incidence rate of CAP requiring hospitalization was 259 (95% CI: 246–272) and age-standardized rate was 294 (95% CI: 280–309) per 100,000 person-years. Among those aged 80 years and older, hospitalization rate was 17 times higher vs those aged 18–64 years, yielding an IRR 17.4 (95% CI: 15.4–19.7). Males aged ≥ 80 years had a 57% increased risk of CAP requiring hospitalization compared to women ≥ 80 years, resulting in an IRR of 1.57 (95% CI: 1.33–1.85). The lowest in-hospital case-fatality risk was among the 18–64 years group 3.4% (n = 16), and highest among those ≥ 80 years 8.1% (n = 46). Conclusion We found that the incidence and mortality of CAP requiring hospitalization in adults are considerable. Preventive measures are needed that target older adults and those at increased risk of CAP.

BackgroundThe risk of infection-related death is high in patients undergoing dialysis. This study aimed to identify the modifiable risk factors for PD-related infections in patients undergoing peritoneal dialysis.MethodsThis was a population-based retrospective cohort study conducted in Skåne, South Sweden, which included all patients receiving peritoneal dialysis (PD) between 2011 and 2020. The primary outcome was PD-related peritonitis, and the secondary outcome was a composite of PD-related infections, that is, peritonitis, exit site, or tunnel infections. Time-to-event frailty models, unadjusted and adjusted for age at PD start, sex and Charleson comorbidity index, were used to investigate potentially modifiable risk factors for PD-related infections. Cox regression models were subsequently used to analyze the relationship between PD-related infection episodes and all-cause mortality during the study period.ResultsIn total, 545 patients were included in the study, of whom 212 (39%) patients had at least one episode of peritonitis during a median follow-up time of 1.6 years. We found that BMI ≥ 30 may be associated with a clinically relevant increased risk for PD-related infection (aHR 1.45, 95% CI 1.08-1.93, p-value 0.012, nevents = 486), but not for peritonitis alone (adjusted Hazard Ratio, aHR, 1.34, 95% CI 0.95- 1.91; p = 0.099; nevents = 365). Patients with >3 peritonitis episodes had an almost three-fold increased risk of all-cause mortality (aHR, 2.66; 95% CI 1.56-4.52, p < 0.001).ConclusionWe found that a BMI ≥ 30 may be a modifiable risk factor for peritoneal dialysis-related infections and that multiple episodes of infectious complications of peritoneal dialysis are associated with increased all-cause mortality.

Beta-lactam antibiotics are essential in the treatment of Gram-negative bloodstream infections. The effect of beta-lactam antibiotics depends on the time of unbound antibiotic concentration above the minimal inhibitory concentration (MIC). An antibiotic concentration above MIC during the whole dosing interval (100

Empiric combination antibiotic therapy (ECAT) is commonly used to treat healthcare-associated bloodstream infections (HA-BSIs) and sepsis. However, the level of supporting evidence is low and clinical practice varies significantly. We conducted a post hoc analysis using the EUROBACT-2 international cohort study database, which contained data on 2406 adult patients from 328 intensive care units (ICUs) across 52 countries, collected between June 2019 and January 2021. The main outcome was the proportion of patients receiving ECAT for HA-BSIs. Patient and institutional factors influencing the use of ECAT were examined using Markov-Chain Monte Carlo estimation. Three quarters of patients (75.2%; n = 1810) received empiric antibiotic therapy, with ECAT used in approximately half of cases (52.5%; n = 950). Most patients receiving ECAT (70.4%; n = 669) were treated with two antibiotics, beta-lactams plus glycopeptides being the most common combination (40.2%; n = 382). The odds of ECAT were increased by immune deficiency (OR 1.35 [95% CrI 1.03–1.75]), SOFA scores > 11 (OR 1.77 [95% CrI 1.28–2.46]), uncommon sources of infection (OR 1.63 [95% CrI 1.02–2.59]), and admission to ICUs where > 25% of Enterobacteriaceae isolates produce carbapenemases (OR 2.46 [95% CrI 1.37–4.41). The intra-class correlation coefficients at the ICU and country levels were 23.2% and 4.4%, respectively. In conclusion, factors at the individual, institutional, and national levels may affect the use of ECAT to treat HA-BSIs. Given the impact of institutional variables on the use of ECAT and the inconclusive evidence regarding its potential risks, it is of great importance that treatment is tailored based on local antibiotic stewardship programs and the needs of the individual patient.

INTRODUCTION:Antibiotic concentration target attainment is known to be poor in critically ill patients. Dose adjustment is recommended in patients with altered clearance, obesity and those with bacterial species with intermediate susceptibility. The aim of this study was to investigate the variation of antibiotic concentration in critically ill patients with standard or adjusted dosing regimens. METHODS:The concentration of three beta-lactam antibiotics used in the intensive care unit (ICU) setting, cefotaxime, piperacillin/tazobactam, and meropenem, was measured in patients with confirmed or suspected infection. Mid-dose and trough values were collected during a single dosing interval. The pharmacokinetic endpoints were a free antibiotic concentration that, during the whole dosing interval, was above MIC (100% ƒT > MIC, primary endpoint) or above four times MIC (100% ƒT > 4MIC, secondary endpoint). Non-species related MIC breakpoints were used (1 mg/L for cefotaxime, 8 mg/L for piperacillin/tazobactam, and 2 mg/L for meropenem). RESULTS:We included 102 patients (38 cefotaxime, 30 piperacillin/tazobactam, and 34 meropenem) at a single ICU, with a median age of 66 years. In total, 73% were males, 40% were obese (BMI ≥30) and the median SAPS 3 score was 63 points. Of all patients, 78 patients (76%) reached the primary endpoint (100%ƒT > MIC), with 74% for cefotaxime, 67% for piperacillin/tazobactam and 88% for meropenem. Target attainment for 100% ƒT > 4MIC was achieved in 40 (39%) patients, overall, with 34% for cefotaxime, 30% for piperacillin/tazobactam and 53% for meropenem. In patients with standard dose 71% attained 100%ƒT > MIC and 37% for 100%ƒT > 4MIC. All patients with reduced dose attained 100%ƒT > MIC and 27% attained 100% ƒT > 4MIC. In patients with increased dose 79% attained 100%ƒT > MIC and 48% 100%ƒT > 4MIC respectively. CONCLUSIONS:Beta-lactam antibiotics concentration vary widely in critically ill patients. The current standard dosing regimens employed during the study were not sufficient to reach 100% ƒT > MIC in approximately a quarter of the patients. In patients where dose adjustment was performed, the group with increased dose also had low target attainment, as opposed to patients with dose reduction, who all reached target. This suggests the need for further individualization of dosing where therapeutic drug monitoring can be an alternative to further increase target attainment.

PURPOSE:In a retrospective cohort study of intensive care unit (ICU) admitted adult patients with suspected or confirmed infection, associations between combination versus mono empirical antibiotic therapy and clinical cure at day 7 as well as mortality at day 7 and 28, were investigated. MATERIALS AND METHODS:Patients from the DIANA study were grouped and analysed by combination versus mono antibiotic therapy. Clinical cure was defined as survival and resolution of all signs and symptoms related to the infection. Odds ratios (ORs) were calculated by logistic regression analyses. RESULTS:Of the 1398 included patients, 568 patients (41%) received combination therapy. In total, 641(46%) patients achieved clinical cure and 135 (10%) patients had died as of day 7. There were no significant associations between combination and mono therapy relating to clinical cure and mortality. CONCLUSIONS:This study found no differences in clinical cure and mortality between empirical combination versus mono therapy in a large cohort of ICU patients with a suspected infection.

Tonsillar Fusobacterium necrophorum PCR Ct-values were higher in participants with asymptomatic tonsillar carriage than patients with pharyngeal infections. However, Ct-values were not associated with severity of disease or predictive of development of complications and hence lacked clinical usefulness. The reporting of F. necrophorum Ct-values in clinical samples is not recommended.

Fusobacterium necrophorum is a common cause of pharyngotonsillitis. However, no guidelines exist on when to diagnose or treat it. We aimed to investigate associations between clinical criteria and F. necrophorum-positivity in pharyngotonsillitis and assess the predictive potential of a simple scoring system. Pharyngotonsillitis patients who were tested for F. necrophorum (PCR) and presented to hospitals in the Skåne Region, Sweden, between 2013–2020 were eligible. Data were retrieved from electronic chart reviews and registries. By logistic regression we investigated associations between F. necrophorum-positivity and pre-specified criteria: age 13–30 years, symptom duration ≤ 3 days, absence of viral symptoms (e.g. cough, coryza), fever, tonsillar swelling/exudate, lymphadenopathy and CRP ≥ 50 mg/L. In secondary analyses, associated variables were weighted by strength of association into a score and its predictive accuracy of F. necrophorum was assessed. Among 561 cases included, 184 (33

Objectives A rising incidence of septic shock as well as recommendations for early vasopressor initiation has increased the number of patients eligible for norepinephrine (NE). Traditionally, NE has been administered through central lines, in intensive care units, due to the risk of extravasation in peripheral lines. The aim of the current study is to determine the rate of complications and patient outcomes when NE is administered through midline catheters (MCs) in intermediary care units (IMCUs).Design Retrospective cohort study.Setting Three IMCUs in southern SwedenParticipants Patients with septic shock who received NE through a MC from September 2020 through March 2023.Primary and secondary outcome measures The primary outcome was a major complication to treatment, defined as extravasation of NE, catheter-associated venous thromboembolism and catheter-associated bloodstream infection (BSI). Secondary outcomes included patient outcomes after intermediary care (either deceased, discharged to regular ward care or intensive care) and the need for additional central lines.Results Of 474 eligible patients, 472 were included, with a median (IQR) age of 73.5 (65–80) years, with 281 (60%) men. The median (IQR) duration of NE infusion was 21 (9–38) hours, with a median (IQR) dosage of 0.12 (0.08–0.20) µg/kg/min. Major complications occurred in 12 cases (2.5%), with one suspected extravasation, seven thromboembolic events and four catheter-related BSIs. After intermediary care, 334 patients (71%) were discharged to regular ward care, 66 patients (14%) were escalated to intensive care and 72 (15%) died in intermediary care, of whom 69 had a documented ceiling of care decision. 100 patients (21%) received a central line.Conclusion NE administration in MCs was associated with a low rate of short-term complications and could decrease the need for central lines. MCs can enable the initial management of circulatory failure outside intensive care, but more studies are needed to determine the long-term value of IMCUs.Trial registration number NCT06121115.

Objective To validate Vergouwe's prediction model using the Swedish and Norwegian Testicular Cancer Group (SWENOTECA) RETROP database and to define its clinical utility. Materials and methods Vergouwe's prediction model for benign histopathology in post‐chemotherapy retroperitoneal lymph node dissection (PC‐RPLND) uses the following variables: presence of teratoma in orchiectomy specimen; pre‐chemotherapy level of alpha‐fetoprotein; β‐Human chorionic gonadotropin and lactate dehydrogenase; and lymph node size pre‐ and post‐chemotherapy. Our validation cohort consisted of patients included in RETROP, a prospective population‐based database of patients in Sweden and Norway with metastatic nonseminoma, who underwent PC‐RPLND in the period 2007–2014. Discrimination and calibration analyses were used to validate Vergouwe's prediction model results. Calibration plots were created and a Hosmer–Lemeshow test was calculated. Clinical utility, expressed as opt‐out net benefit (NB opt‐out ), was analysed using decision curve analysis. Results Overall, 284 patients were included in the analysis, of whom 130 (46%) had benign histology after PC‐RPLND. Discrimination analysis showed good reproducibility, with an area under the receiver‐operating characteristic curve (AUC) of 0.82 (95% confidence interval 0.77–0.87) compared to Vergouwe's prediction model (AUC between 0.77 and 0.84). Calibration was acceptable with no recalibration. Using a prediction threshold of 70% for benign histopathology, NB opt‐out was 0.098. Using the model and this threshold, 61 patients would have been spared surgery. However, only 51 of 61 were correctly classified as benign. Conclusions The model was externally validated with good reproducibility. In a clinical setting, the model may identify patients with a high chance of benign histopathology, thereby sparing patients of surgery. However, meticulous follow‐up is required.

Background and AimsTransient elastography (TE) has largely replaced liver biopsy to evaluate fibrosis stage and cirrhosis in chronic hepatitis C. Previous studies have reported excellent reliability of TE but agreement metrics have not been reported. This study aimed to assess interrater agreement and reliability of repeated TE measurements. MethodsTwo operators performed TE independently, directly after each other. The primary outcome was disagreement, defined as a difference in TE results between operators of >= 33%, as well as the smallest detectable change, SDC95 (i.e., the difference between measurements needed to state with 95% certainty that there is a difference in underlying stiffness). Secondary outcomes included reliability, measured as intraclass correlation (ICC), and patient and examination characteristics associated with the agreement. ResultsIn total, 65 patients were included, with a mean liver stiffness of 9.7 kPa. Of these, 21 (32%) had a disagreement in TE results of >= 33% between the two operators. The SDC95 on the log scale was 1.97, indicating that an almost twofold increase or decrease in liver stiffness would be required to confidently represent a change in the underlying fibrosis. Reliability, estimated using the ICC, was acceptable at 0.86. In a post hoc analysis, fasting less than 5 h before TE was associated with a higher degree of disagreement (48% vs. 19%, p = 0.03). ConclusionsIn our clinical setting, interrater agreement in directly repeated TE measurements was surprisingly low. It is essential to further investigate the reliability and agreement of TE to determine its validity and usefulness.

BackgroundBloodstream infections (BSI) are a public health concern, and infections caused by resistant bacteria further increase the overall BSI burden on healthcare.AimTo provide a population-based estimate of BSI incidence and relate this to the forthcoming demographic ageing western population change.MethodsWe retrieved positive blood cultures taken from patients in the Skåne region, southern Sweden, 2006-2019 from the Clinical Microbiology Department database and estimated incidence rates (IR), stratified by age (0-49, 50-64, 65-79, ≥ 80 years), sex, year, and species and described antimicrobial susceptibility for Enterobacterales.ResultsWe identified 944,375 blood culture sets, and 129,274 (13.7%) were positive. After deduplication and removal of contaminants, 54,498 separate BSI episodes remained. In total, 30,003 BSI episodes (55%) occurred in men. The overall IR of BSI was 307/100,000 person-years, with an average annual increase of 3.0%. Persons ≥ 80 years had the highest IR, 1781/100,000 person-years, as well as the largest increase. Escherichia coli (27%) and Staphylococcus aureus (13%) were the most frequent findings. The proportion of Enterobacterales isolates resistant to fluoroquinolones and third generation cephalosporins increased from 8.4% to 13.6%, and 4.9% to 7.3%, (p for trend < 0.001), with the largest increase in the oldest age group.ConclusionWe report among the highest BSI IRs to date worldwide, with a higher proportion among elderly persons and males, including resistant isolates. Given expected demographic changes, these results indicate a possible substantial future BSI burden, for which preventive measures are needed.

ObjectivesIn Sweden, pneumococcal serotype distribution in adults with community-acquired pneumonia (CAP) and potential coverage of currently licensed pneumococcal conjugate vaccines (PCVs) is unknown.MethodsDuring 2016–2018, patients aged ≥18 years hospitalized with radiologically confirmed (RAD+) CAP were enrolled at Skåne University Hospital in a study on the etiology of CAP in Sweden (ECAPS). Urine samples and blood cultures were collected per-protocol. Streptococcus pneumoniae (Spn) culture isolates were serotyped and urine samples tested for the pan-pneumococcal urinary antigen (PUAT) and multiplex urine antigen detection (UAD) assay, detecting 24 serotypes.ResultsAnalyses included 518 participants with RAD+CAP; 67.4% were ≥65 years of age, 73.4% were either immunocompromised or had an underlying chronic medical condition. The proportion of CAP due to Spn identified by any method was 24.3% of which 9.3% was detected by UAD alone. The most frequently identified serotypes were 3 (26 cases, 5.0% of all CAP), and 8, 11A and 19A (10 cases each, 1.9%). In individuals aged 18–64 and ≥65 years, respectively, PCV20 serotypes contributed to 35 of 169 (20.7%) and 53 of 349 cases of all CAP (15.2%), and PCV13 serotypes caused 21 of 169 (12.4%) and 35 of 349 (10.0%) cases. PCV15 coverage was 23 of 169 (13.6%) and 42 of 349 (12.0%) in individuals aged 18–64 and ≥65 years, respectively. Overall, PCV20 increases the coverage of all CAP from 10.8% (PCV13) to 17.0%.ConclusionCompared to earlier pneumococcal vaccines, PCV20 expands the coverage of all-cause CAP. Routine diagnostic tests underestimate the proportion of CAP caused by Spn.

Background The underlying mechanisms of thrombosis in Lemierre's syndrome and other septic thrombophlebitis are incompletely understood. Therefore, in this case control study we aimed to generate hypotheses on its pathogenesis by studying the plasma proteome in patients with these conditions. Methods All patients with Lemierre's syndrome in the Skåne Region, Sweden, were enrolled prospectively during 2017 to 2021 as cases. Age-matched patients with other severe infections were enrolled as controls. Patient plasma samples were analyzed using label-free data-independent acquisition liquid chromatography tandem mass spectrometry. Differentially expressed proteins in Lemierre's syndrome versus other severe infections were highlighted. Functions of differentially expressed proteins were defined based on a literature search focused on previous associations with thrombosis. Results Eight patients with Lemierre's syndrome and 15 with other severe infections were compared. Here, 20/449 identified proteins were differentially expressed between the groups. Of these, 14/20 had functions previously associated with thrombosis. Twelve of 14 had a suggested prothrombotic effect in Lemierre's syndrome, whereas 2/14 had a suggested antithrombotic effect. Conclusion Proteins involved in several thrombogenic pathways were differentially expressed in Lemierre's syndrome compared to other severe infections. Among identified proteins, several were associated with endothelial damage, platelet activation, and degranulation, and warrant further targeted studies.

Abstract Background Most pharyngotonsillitis guidelines focus on the identification of group A streptococci (GAS), guided by clinical scores determining whom to test with a rapid antigen detection test. Nevertheless, many patients testing negative with this test are evaluated for group C/G streptococci (GCS/GGS) and Fusobacterium necrophorum, yet their importance remains debated. Our primary aim was to evaluate associations between complications and findings of F. necrophorum, GAS, or GCS/GGS in pharyngotonsillitis. Methods This was a retrospective, registry-based study of pharyngotonsillitis cases tested for F. necrophorum (polymerase chain reaction) and β-hemolytic streptococci (culture) in the Skåne Region, Sweden, in 2013–2020. Patients with prior complications or antibiotics (within 30 days) were excluded. Data were retrieved from registries and electronic charts. Logistic regression analyses were performed with a dichotomous composite outcome of complications as primary outcome, based on International Classification of Diseases, Tenth Revision, codes. Cases with negative results (polymerase chain reaction and culture) were set as reference category. Complications within 30 days were defined as peritonsillar or pharyngeal abscess, otitis, sinusitis, sepsis or septic complications, recurrence of pharyngotonsillitis (after 15–30 days) or hospitalization. Results Of 3700 registered cases, 28% had F. necrophorum, 13% had GCS/GGS, 10% had GAS, and 54% had negative results. The 30-day complication rates were high (20%). F. necrophorum (odds ratio, 1.8; 95% confidence interval, 1.5–2.1) and GAS (1.9; 1.5–2.5) were positively associated with complications, whereas GCS/GGS were negatively associated (0.7; 0.4–0.98). Conclusions Our results indicate that F. necrophorum is a relevant pathogen in pharyngotonsillitis, whereas the relevance of testing for GCS/GGS is questioned. However, which patient to test and treat for F. necrophorum remains to be defined.