Time to positivity of Klebsiella pneumoniae in blood cultures as prognostic marker in patients with intra-abdominal infection: A retrospective study

Klebsiella pneumoniae is a common causative pathogen of intra-abdominal infection with concomitant bacteraemia, leading to a significant mortality risk. The time to positivity (TTP) of blood culture is postulated to be a prognostic factor in bacteraemia caused by other species. Therefore, this study aimed to investigate the prognostic value of TTP in these patients. The single-centred, retrospective, observational cohort study was conducted between 1 July 2016 and 30 June 2021. All adult emergency department patients with diagnosis of intra-abdominal infection and underwent blood culture collection which yield K. pneumoniae during this period were enrolled. A total of 196 patients were included in the study. The overall 30-day mortality rate was 12.2% (24/196), and the median TTP of the studied cohort was 12.3 h (10.5-15.8 h). TTP revealed a moderate 30-day mortality discriminative ability (area under the curve 0.73, p < 0.001). Compared with the late TTP group (>12 h, N = 109), patients in the early TTP (≤12 h, N = 87) group had a significantly higher risk of 30-day morality (21.8% vs. 4.6%, p < 0.01) and other adverse outcomes. Furthermore, TTP (odds ratio [OR] = 0.79, p = 0.02), Pitt bacteraemia score (OR = 1.30, p = 0.03), and implementation of source control (OR = 0.06, p < 0.01) were identified as independent factors related to 30-day mortality risk in patients with intra-abdominal infection and K. pneumoniae bacteraemia. Therefore, physicians can use TTP for prognosis stratification in these patients.

Benchmarking blood culture quality in the emergency department: Contamination, single sets and positivity

OBJECTIVE

To benchmark blood culture (BC) quality in an Australian ED, explore groups at risk of suboptimal BC collection, and identify potential areas for improvement.

METHODS

This retrospective observational study was undertaken to benchmark quality of BCs in a tertiary adult ED in terms of number of BC sets per patient and proportion of patients with false positive (contaminated) BC results.

RESULTS

A single BC set was taken for 55% of patients, with lower acuity patients being more likely to have a single BC set taken. BC false positives occurred in 3.4% of presentations, with higher frequency in some critically unwell patient groups. The true positive BC rate was 10.9%, with pathogens most frequently isolated in older patients, those with a haematological condition or genitourinary source, and those admitted to inpatient wards. Hospital length of stay did not differ between patients with negative and patients with false positive BCs.

CONCLUSIONS

BC quality standards in the ED such as false positive rate <3% and single culture rate <20% are required to facilitate benchmarking and prospective quality improvement. The sensitivity and specificity of this common and critical test can be improved. Patient subgroups associated with poor-quality BC collection can be identified and should be a focus of future work.

Staphylococcus aureus bacteraemia, cardiac implantable electronic device, extraction, and the risk of recurrent infection; a retrospective population-based cohort study

BACKGROUND

Patients with cardiac implantable electronic device (CIED) and Staphylococcus aureus bacteraemia (SAB) are at risk of having CIED infection, pocket infection or endocarditis. To avoid treatment failures, guidelines recommend that the CIED should be extracted in all cases of SAB butrecent studies indicate low extraction rates and low risk of relapse. The aim of the study was to describe a Swedish population-based cohort of patients with CIED and SAB, the rate of extraction, and treatment failure measured as recurrent SAB.

METHODS

Patients identified to have SAB in the Karolinska Laboratory database, serving a population of 1.9 million, from January 2015 through December 2019 were matched to the Swedish ICD and Pacemaker Registry. Patients with CIED and SAB were included. Clinical data were collected from medical records.

RESULTS

A cohort of 274 patients was identified and 38 patients (14%)had the CIED extracted. Factors associated with extraction were lower age, lower Charlson comorbidity index, shorter time since CIED implantation, and non-nosocomial acquisition, but not mortality. No patient was put on lifelong antibiotic treatment. Sixteen patients (6%) had a recurrent SAB within one year, two in patients subjected to extraction (5%) and 14 in patients not subjected to CIED-extraction (6%). Three of the 14 patients were found to have definite endocarditis during the recurrent episode.

CONCLUSIONS

Despite a low extraction rate, there were few recurrences. We suggest that extraction of the CIED might be omitted if pocket infection, changes on the CIED, or definite endocarditis are not detected.

Clinical and microbiological profile of Viridans group streptococcal bacteraemia; experience from South India

Background

Viridans Group Streptococci (VGS) are a group of distinct species that can cause bacteraemia and other invasive infections. They are also among the common organisms causing infective endocarditis. Data on the epidemiology and clinical profile of VGS is limited, especially from India.

Methods

We conducted an electronic medical record-based retrospective analysis of patients with VGS bacteraemia admitted to our hospital between January 2012 to December 2021. Blood cultures were incubated by BacT/ALERT system and bacterial identification and susceptibility testing were done by using the VITEK 2 microbial identification system. Susceptibility test reporting was as per Clinical and Laboratory Standards Institute (CLSI) guidelines. The incidence, clinical profile, source of bacteraemia, co-morbidities and antimicrobial resistance among VGS bacteraemia were analyzed.

Results

VGS were isolated in 219 patients, accounting for 3.2% of positive blood cultures during the period studied. The median age of the patients was 58 years and 69% were males. Diabetes mellitus was the most common co-morbidity (55%) followed by chronic kidney disease and chronic liver disease. Patients with haematological malignancy and neutropenia were few. Intra-abdominal infections were the most common source of infection and was noted in 26%. Infective endocarditis was diagnosed in only 10% of the cases. Streptococcus mitis was the most common species isolated followed by S. gallolyticus and S. sanguinis. 9.58% of the isolates could not be identified up to the species level. Overall penicillin susceptibility was 71% and ceftriaxone susceptibility was 92%, with individual species variation. In-hospital mortality was 19%.

Conclusions

VGS are an important cause of bacteraemia and was associated with 19% mortality in our study. High rates of penicillin and ceftriaxone resistance are a reason of concern. Molecular diagnostics like matrix assisted laser desorption ionization-time of flight (MALDI-TOF) identification must be increasingly applied for species identification considering that a substantial number of isolates were not identified to species level.

Retrospective cohort study comparing two versus three blood culture sets in people who inject drugs

BACKGROUND

The current standard of drawing two vs three blood culture sets lacks adequate guidance. Because people who inject drugs are at higher risk for bacteraemia and life-threatening infection, consideration of a third blood culture becomes more important.

AIM

To investigate the risks and benefits of obtaining two versus three blood culture sets.

METHODS

Retrospective cohort study of adults who inject drugs at a multicentre catch-net hospital system from 2017-2022.

FINDINGS

998 people who inject drugs and 2278 blood culture sets were analysed. There were 1618 episodes with two blood culture sets and 660 episodes with three. A potential benefit of adding a third blood culture was seen in 30 (4.5%) episodes. However, only 13 (2.0%) episodes showed pathogen-identifying benefit, as 17 (2.6%) involved known inadequately treated infections or the same pathogen in another culture. The number of blood culture sets needed to achieve diagnostic benefit was 51. There were more contaminants for three blood culture sets (65, 9.8%) than for two (114, 7.0%) (p < 0.00001). By adding a third blood culture, the risk of a contaminant increased by 39.7%; the number of blood culture sets needed to find a contaminant was 36. Of 122 episodes with only contaminants and available for analysis, 111 (91.0%) experienced at least one complication. 33 (27.0%) patients experienced either prolonged admission, readmission, or unnecessary antibiotic administration.

CONCLUSIONS

The benefits of possibly isolating a pathogen from a third blood culture set do not universally outweigh the risks for contaminant growth for people who inject drugs. A third blood culture should be considered in specific clinical scenarios (i.e. inadequately treated endocarditis and osteomyelitis).

Gingival Necrosis Related to Sepsis-Induced Agranulocytosis Due to Pseudomonas aeruginosa Bacteraemia: A Case Report

Background: There have been no reports of sepsis-induced agranulocytosis causing gingival necrosis in otherwise medically healthy patients to the authors' best knowledge. Even though there are several case reports of gingival necrosis secondary to medication-induced agranulocytosis, they have not systematically described the natural progression of agranulocytosis-related gingival necrosis. Methods: This paper presents a case report of a 29-year-old female Indian patient with generalised gingival necrosis and constitutive signs of intermittent fever, nausea, and vomiting. She also complained of abdominal pains. Blood counts showed agranulocytosis, and the patient was admitted for a workup of the underlying cause. Parenteral broad-spectrum antibiotics were administered, which brought about clinical resolution. Results: Her gingival necrosis was attributed to sepsis-induced agranulocytosis triggered by Pseudomonas aeruginosa bacteraemia, and upon clinical recovery, spontaneous exfoliation left behind exposed bone. Secondary healing over the exposed alveolar bone was noted after a year-long follow-up, albeit with some residual gingival recession. Conclusions: Oral manifestations of gingival necrosis, when present with concomitant constitutive symptoms, could indicate a serious underlying systemic condition that could be potentially life-threatening if left untreated. Dentists should be cognizant of this possibility so that timely intervention is not delayed.

Cephalotin Versus Dicloxacillin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteraemia: A Retrospective Cohort Study

BACKGROUND

First-line treatments for methicillin-susceptible S. aureus (MSSA) bacteraemia are nafcillin, oxacillin, or cefazolin. Regional shortages of these antibiotics force clinicians to use other options like dicloxacillin and cephalotin. This study aims to describe and compare the safety and efficacy of cephalotin and dicloxacillin for the treatment of MSSA bacteraemia.

METHODS

This retrospective study was conducted in a referral centre in Mexico City. We identified MSSA isolates in blood cultures from 1 January 2012 to 31 December 2022. Patients ≥ 18 years of age, with a first episode of MSSA bacteraemia, who received cephalotin or dicloxacillin as the definitive antibiotic treatment, were included. The primary outcome was in-hospital all-cause mortality.

RESULTS

We included 202 patients, of which 48% (97/202) received cephalotin as the definitive therapy and 52% (105/202) received dicloxacillin. In-hospital all-cause mortality was 20.7% (42/202). There were no differences in all-cause in-hospital mortality between patients receiving cephalotin or dicloxacillin (20% vs. 21%, p = 0.43), nor in 30-day all-cause mortality (14% vs. 18%, p = 0.57) or 90-day all-cause mortality (24% vs. 22%, p = 0.82). No severe adverse reactions were associated with either antibiotic.

CONCLUSIONS

Cephalotin and dicloxacillin were equally effective for treating MSSA bacteraemia, and both showed an adequate safety profile.

Community-acquired Staphylococcus aureus bacteraemia among people who inject drugs: a national cohort study in England, 2017-2020

BACKGROUND

People who inject drugs (PWID) are at increased risk of community-acquired Staphylococcus aureus bacteraemia (CA-SAB), but little is known about clinical outcomes of CA-SAB in PWID compared with the wider population of patients with CA-SAB.

METHODS

Three national datasets were linked to provide clinical and mortality data on patients hospitalised with CA-SAB in England between 1 January 2017 and 31 December 2020. PWID were identified using the ICD-10 code for "mental health and behavioural disorder due to opioid use" (F11). Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) for associations of PWID with 30-day all-cause mortality and 90-day hospital readmission.

RESULTS

In 10,045 cases of CA-SAB, 1,612 (16.0%) were PWID. Overall, 796 (7.9%) patients died within 30 days of CA-SAB admission and 1,189 (11.8%) patients were readmitted to hospital within 90 days of CA-SAB. In those without infective endocarditis there was strong evidence of lower odds of mortality among PWID compared with non-PWID (aOR: 0.47, 95% confidence interval, CI: 0.33-0.68, p < 0.001) whereas there was no association in CA-SAB case fatality with endocarditis (aOR 1.40, CI 0.87-2.25, p = 0.163). PWID were less likely to be re-admitted within 90 days of CA-SAB (aOR 0.79, CI 0.65-0.95, p = 0.011).

CONCLUSIONS

In this large cohort study of patients with CA-SAB in England, PWID had lower odds of death in the absence of endocarditis and lower odds of re-admission within 90 days compared to non-PWID patients. This study highlights the over-representation of PWID among patients with CA-SAB nationally.

Short communication: first case of bacteraemia caused by Dielma fastidiosa in a patient hospitalized with diverticulitis

Dielma fastidiosa is a gram-negative, anaerobic rod belonging to the family Erysipelotrichaceae. D. fastidiosa has previously been isolated in human stool samples as part of the commensal flora; however, prior to this case, it has never been identified as a human pathogen. We present the first case of bacteraemia with D. fastidiosa. Bacterial growth in the blood culture bottle was detected by the automated blood culture system BacT/ALERT 3D. Culturing was performed, and bacterial colonies were identified as D. fastidiosa using MALDI-TOF MS. A subsequent whole-genome sequencing using Illumina NovaSeq was performed, and a phylogenetic tree depicting all available sequences of D. fastidiosa was generated. The reference MALDI-TOF spectrum and species identification was compared with the previously published spectrum. Whole-genome sequencing confirmed the tentative MALDI-TOF species identification. Notably, the maximum-likelihood-based phylogenetic analysis placed the D. fastidiosa isolate from this clinical case within the known variation of the eight publicly available sequences of this species. We identified D. fastidiosa by whole-genome sequencing followed by maximum-likelihood analysis as a possible pathogen in this case of bacteraemia in a patient hospitalized with diverticulitis.

Staphylococcus hemolyticus: The Most Common and Resistant Coagulase-Negative Staphylococcus Species Causing Bacteremia in North India

INTRODUCTION

Coagulase-negative Staphylococcus (CoNS) species are normal skin commensals but may also cause bacteremia. Therefore, isolating a CoNS species on blood culture often leads to a diagnostic dilemma about whether to consider the isolate as a true pathogen or not. This study was done to understand the distribution of various CoNS species in bloodstream infections, determine their antibiotic resistance patterns, and identify possible risk factors and patient outcomes in hospital settings.

MATERIALS AND METHODS

Inpatients with confirmed bacteremia defined as isolation of the same CoNS species with similar antibiograms from paired blood culture bottles, which were obtained from patients with at least clinical evidence of infection, were included. The isolates obtained were studied for CoNS species distribution and antibiotic resistance patterns, and the corresponding patients were assessed for possible risk factors and outcomes.

RESULTS

A total of 170 CoNS isolates obtained from 85 patients were analyzed. Staphylococcus haemolyticus (S. haemolyticus)(90, 52.9%) was the most common species isolated, and it was also the most resistant of all, followed by S. hominis (50, 29.4%), S. epidermidis (26, 15.3%), S. lentus (2,1.2%), and S. succinus (2,1.2%). S. haemolyticus and S. hominis were significantly more isolated from patients aged 18-60 years and >60 years, respectively. Methicillin-resistant (MR)-CoNS (68.8%) were significantly more resistant than methicillin-sensitive (MS)-CoNS (31.2%) to certain antibiotics, and none were resistant to vancomycin, linezolid, or teicoplanin. Mortality occurred in 17.6% of patients, which was most commonly associated with S. haemolyticus infection.

CONCLUSION

Age-specific predisposition of CoNS species, high rates of methicillin resistance, and mortality in CoNS bacteremia are highlights of this study. To our knowledge, we are the first to study the age-related association of CoNS species.

Recurrent cholangitis and bacteraemia due to Edwardsiella tarda: a case report

Edwardsiella tarda is typically isolated from aquatic environments. It rarely causes infections in humans. Edwardsiella tarda infections in humans result from the consumption of infected or contaminated food. Here, we present a case of recurrent cholangitis and bacteraemia associated with E. tarda. An 82-year-old man with no history of seafood inoculation was admitted to our hospital because of difficulty in moving his body. The patient was diagnosed with cholangitis, and the blood culture revealed the presence of E. tarda. The patient underwent bile duct stenting and received antibiotic therapy for 14 days. Forty-four days after discharge, cholangitis recurred, and blood culture again showed the presence of E. tarda. The patient underwent bile duct stenting and antibiotic therapy for 11 days. No cholangitis or bacteraemia associated with E. tarda was observed in the following 3 years. Our case strongly suggests that colonization with E. tarda results in recurrent cholangitis and bacteraemia.

Vibrio species bloodstream infections in Queensland, Australia

BACKGROUND

Vibrio species bloodstream infections have been associated with significant mortality and morbidity. Limited information is available regarding the epidemiology of bloodstream infections because of Vibrio species in the Australian context.

AIMS

The objective of this study was to define the incidence and risk factors for developing Vibrio species bloodstream infections and compare differences between different species.

METHODS

All patients with Vibrio spp. isolated from positive blood cultures between 1 January 2000 and 31 December 2019 were identified by the state-wide Pathology Queensland laboratory. Demographics, clinical foci of infections and comorbid conditions were collected in addition to antimicrobial susceptibility results.

RESULTS

About 100 cases were identified between 2000 and 2019 with an incidence of 1.2 cases/1 million person-years. Seasonal and geographical variation occurred with the highest incidence in the summer months and in the tropical north. Increasing age, male sex and multiple comorbidities were identified as risk factors. Vibrio vulnificus was isolated most frequently and associated with the most severe disease. Overall case fatality was 19%.

CONCLUSIONS

There is potential for increasing cases of Vibrio species infections globally with ageing populations and climate change. Ongoing clinical awareness is required to ensure optimal patient outcomes.

Williamsia muralis bacteraemia in a patient with Fanconi anaemia after haematopoietic cell transplantation

Introduction

Williamsia muralis is an environmental bacterium first detected in 1999. Infections with W. muralis isolated have been reported in two elderly patients, and were associated with the surgical intervention of artificial objects. We present a case of bacteraemia caused by W. muralis following haematopoietic cell transplantation (HCT).

Case presentation

A 10-year-old Japanese boy presented with fever and the swelling of the left cheek 8 days after HCT for the treatment of Fanconi anaemia. Gram-positive, rod-shaped bacteria were isolated from the blood cultures after 5 days incubation. 16S rRNA sequencing, but not mass spectrometry, identified a strain of W. muralis (1 414 bp, %ID 100 %). The phlegmon did not respond to antimicrobial therapy, but remitted with defervescence after a successful engraftment with teicoplanin and meropenem therapy on day 16 after HCT. The patient experienced recurrence of the bacteraemia, leading to central venous catheter (CVC) line removal. The same strain of W. muralis was isolated from the cultured tip of the CVC. To our knowledge, this is the first reported case of W. muralis bacteraemia and was complicated by CVC infection after HCT.

Conclusion

W. muralis bacteraemia developed in an immunocompromised child. Introduction of artificial objects into the body raises a risk of rare infection with slowly growing environmental bacteria.

Australian Group on Antimicrobial Resistance (AGAR) Australian Staphylococcus aureus Surveillance Outcome Program (ASSOP) Bloodstream Infection Annual Report 2022

From 1 January to 31 December 2022, fifty-five institutions across Australia participated in the Australian Staphylococcus aureus Surveillance Outcome Program (ASSOP). The aim of ASSOP 2022 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that were antimicrobial resistant, with particular emphasis on susceptibility to methicillin and on characterisation of the molecular epidemiology of the methicillin-resistant isolates. A total of 3,214 SAB episodes were reported, of which 77.5% were community-onset. Overall, 15.0% of S. aureus were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 21.4%, which was significantly different to the 16.8% all-cause mortality associated with methicillin-susceptible SAB (p = 0.02). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However, in addition to the β-lactams, approximately 31% of methicillin-resistant S. aureus (MRSA) were resistant to ciprofloxacin; 30% to erythromycin; 13% to tetracycline; 11% to gentamicin; and 2% to co-trimoxazole. One MRSA isolate, with a daptomycin MIC of 1.5 mg/L, harboured the A302V mprF and A23V cls2 mutations. When applying the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, teicoplanin resistance was detected in one MRSA isolate. Resistance to vancomycin or linezolid was not detected. Resistance to non-β-lactam antimicrobials was largely attributable to the healthcare-associated MRSA (HA-MRSA) clone ST22-IV [2B] (EMRSA-15), and to the community-associated MRSA (CA-MRSA) clone ST45-V [5C2&5] which has acquired resistance to multiple antimicrobials including ciprofloxacin, clindamycin, erythromycin, gentamicin, and tetracycline. The ST22-IV [2B] (EMRSA-15) clone is the predominant HA-MRSA clone in Australia. Nonetheless, 86% of methicillin-resistant SAB episodes were due to CA-MRSA clones. Although polyclonal, approximately 72% of CA-MRSA clones were characterised as ST93-IV [2B] (Queensland clone); ST5-IV [2B]; ST45-V [5C2&5]; ST1-IV [2B]; ST30-IV [2B]; ST97-IV [2B]; ST953-IV [2B]; and ST8-IV [2B]. As CA-MRSA is well established in the Australian community, it is important to monitor antimicrobial resistance patterns in community- and healthcare-associated SAB as this information will guide therapeutic practices in treating S. aureus bacteraemia.

Australian Group on Antimicrobial Resistance (AGAR) Australian Gram-negative Surveillance Outcome Program (GnSOP) Bloodstream Infection Annual Report 2022

The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2022 survey was the tenth year to focus on blood stream infections caused by Enterobacterales, and the eighth year where Pseudomonas aeruginosa and Acinetobacter species were included. Fifty-five hospitals Australia-wide participated in 2022. The 2022 survey tested 9,739 isolates, comprising Enterobacterales (8,773; 90.1%), P. aeruginosa (840; 8.6%) and Acinetobacter species (126; 1.3%), using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2023). Key resistances included resistance to the third-generation cephalosporin ceftriaxone in 12.7%/12.7% (CLSI/EUCAST criteria) of Escherichia coli and in 6.6%/6.6% of Klebsiella pneumoniae complex. Resistance rates to ciprofloxacin were 13.7%/13.7% for E. coli; 7.8%/7.8% for K. pneumoniae complex; 5.3%/5.3% for Enterobacter cloacae complex; and 4.3%/10.0% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 2.8%/5.9%; 2.9%/8.7%; 18.3%/27.2%; and 6.1%/14.7% for the same four species, respectively. Twenty-nine Enterobacterales isolates from 28 patients were shown to harbour a carbapenemase gene: 18 blaIMP-4; four blaNDM-5; three blaNDM-1; one blaOXA-181; one blaOXA-244; one blaNDM-1 + blaOXA-181; and one blaNDM-5 + blaOXA-181. Transmissible carbapenemase genes were also detected among two Acinetobacter baumannii complex isolates (blaOXA-23) and one P. aeruginosa (blaNDM-1) in the 2022 survey.

Australian Group on Antimicrobial Resistance (AGAR) Australian Enterococcal Surveillance Outcome Program (AESOP) Bloodstream Infection Annual Report 2022

From 1 January to 31 December 2022, fifty-five institutions across Australia participated in the Australian Enterococcal Surveillance Outcome Program (AESOP). The aim of AESOP 2022 was to determine the proportion of enterococcal bacteraemia isolates in Australia that were antimicrobial resistant, and to characterise the molecular epidemiology of the Enterococcus faecium isolates. Of the 1,535 unique episodes of enterococcal bacteraemia investigated, 92.8% were caused by either E. faecalis (52.9%) or E. faecium (39.9%). Ampicillin and vancomycin resistance were not detected in E. faecalis but were detected in 95.4% and 46.9% of E. faecium respectively. One E. faecalis isolate, with a daptomycin minimum inhibitory concentration (MIC) of 8.0 mg/L, harboured the F478L GdpD mutation. One E. faecium with a daptomycin MIC of 24.0 mg/L harboured the A20D Cls mutation; both mutations are known to be associated with daptomycin resistance. Two E. faecium isolates, one with a linezolid MIC ≥ 256 mg/L and the other with a linezolid MIC of 16 mg/L, harboured the 23S rRNA G2576T mutation, a mutation associated with linezolid resistance in enterococci. Overall, 48.8% of E. faecium harboured either the vanA or the vanB gene, of which 28.0% harboured vanA and 72.0% harboured vanB. The percentage of vancomycin-resistant E. faecium bacteraemia isolates in Australia remains substantially higher than that recorded in most European countries. The E. faecium isolates consisted of 62 multi-locus sequence types (STs); 85.5% of isolates were classified into eight major STs each containing ten or more isolates. All major STs belonged to clonal complex (CC) 17, a major hospital-adapted polyclonal E. faecium cluster. The major STs (ST17, ST78, ST80, ST117, ST555, ST796, ST1421, and ST1424) were each found across most regions of Australia. The predominant ST was ST17, which was identified in all regions. Overall, 53.7% of isolates belonging to the eight major STs harboured the vanA or vanB gene. AESOP 2022 has shown that enterococcal bacteraemia episodes in Australia are frequently caused by polyclonal ampicillin-resistant high-level gentamicin resistant vanA- or vanB-positive E. faecium which have limited treatment options.

Genome Characterisation of Invasive Haemophilus influenzae in Pregnancy: The Noticeable Placental Tissue Tropism Is Distributed across the Species Rather Than Linked with Capsulation or Particular Clones

Pregnancy is associated with a 5-26 times increased risk of invasive Haemophilus influenzae infection and subsequent adverse pregnancy outcomes. Incidence rate and outcome are published in some regions, but the characterisation of bacterial isolates is limited. We performed comparative genomic analyses of isolates from 12 pregnancy-associated cases, cultured from maternal bacteraemia in pregnancy (nine), postpartum bacteraemia (one), neonatal bacteraemia (one), and placental tissue (one). In two bacteraemia cases, identical isolates were also cultured from cervical swabs. Eight cases occurred early in pregnancy (gestational week 7-26), and seven of them resulted in miscarriage or neonatal death. All bacterial genomes were devoid of capsule loci, and they were evenly distributed in the major phylogenetic group I of the species. The conspicuous tropism of H. influenzae for pregnancy and placental tissue is associated with the species rather than specific clonal subtypes.

C-reactive protein and the neutrophil-to-lymphocyte ratio on admission predicting bacteraemia with COVID-19

BACKGROUND

Bacteraemia can co-occur with COVID-19. The present study aimed to determine the cut-off value for C-reactive protein (CRP) and the neutrophil-to-lymphocyte ratio (NLR) for predicting bacteraemia in patients with COVID-19.

METHODS

Patients admitted to Tokyo Metropolitan Tama Medical Centre for COVID-19 treatment between 1 April 2020 and 30 October 2022 were included. Patients transferred from other hospitals and those whose CRP and/or neutrophil count was not measured at admission were excluded. Community-acquired bacteraemia was diagnosed if true bacteraemia was diagnosed in patients via a blood culture performed within 72 h of admission. The cut-off value for CRP and the NLR for community-acquired bacteraemia were determined using receiver operating characteristic analysis.

RESULTS

Among 2989 patients hospitalized for COVID-19 treatment, 19 received the diagnosis of community-acquired bacteraemia, for which CRP ≥ 6.3 was determined to be the cut-off value. The sensitivity and specificity of the cut-off was 89.5% and 73.3%, respectively. The NLR cut-off value was ≥ 7.7, which had a sensitivity and specificity of 84.2% and 84.0%, respectively.

CONCLUSIONS

Considering the possibility of the co-occurrence of bacteraemia with COVID-19, a blood culture should be performed when CRP is ≥ 6.3 or the NLR is ≥ 7.7.

Case Report: A case of disseminated cutaneous listeriosis following appendicitis from Lao PDR

Background

Listeria monocytogenes is a food-borne pathogen that is a rare cause of bacteraemia and meningitis in immunosuppressed patients, and carries a high mortality rate. Cutaneous manifestations of listeriosis are rare, and are usually associated with direct inoculation of the skin.

Case

A 41-year-old woman who initially presented to a hospital in Laos with appendicitis was diagnosed with disseminated cutaneous listeriosis without recognised risk factors. Intra-abdominal pathology probably contributed to bacterial bloodstream invasion. Initial treatment with meropenem was switched to ampicillin based on best practice, however our patient died 5 days after diagnosis.

Conclusions

This case highlights listeriosis as an important cause of mortality in low- and middle-income countries, exacerbated by poor availability of laboratory diagnostics and ineffective empiric antibiotic regimens. Improvements in food hygiene, surveillance, and increased laboratory capacity are important strategies to reduce rates of infection and clinical outcomes.

Identifying barriers and facilitators to seeking care for symptoms of bacterial sepsis: A qualitative study

AIM

Research suggests that early access to quality care is essential to improving bacteraemia outcomes and reducing the risk of developing sepsis because it allows for early intervention. Currently, there are limited data regarding the facilitators and barriers that alter the trajectory of arrival at the hospital when patients in the United States experience symptoms of bacteraemia and sepsis. This study sought to explore and describe the facilitators and barriers to seeking care for suspected bacteraemia and sepsis symptoms.

DESIGN

A qualitative descriptive study.

METHODS

Ten men and women were recruited using convenience sampling. The study used audio-recorded semi-structured interviews and the collection of socio-demographic data as the data collection techniques. Thematic analysis was used, including inductive and deductive approaches, to analyse the data.

RESULTS

During data analysis, the codes related to barriers and facilitators were collapsed into three themes-symptom recognition, psychosocial support and healthcare planning and coordination.

PATIENT CONTRIBUTION

The patients' participation in the study has contributed to our understanding of patients' perspectives and experiences in the pre-hospital phase and provides important insights into what barriers and facilitators are encountered. Study findings highlight the need to develop interventions to improve patient decision time, patient-provider interactions and knowledge of bacteraemia and sepsis through patient and provider education.

Early oral antibiotic switch in Staphylococcus aureus bacteraemia: The Staphylococcus aureus Network Adaptive Platform (SNAP) Trial Early Oral Switch Protocol

BACKGROUND

Staphylococcus aureus bloodstream infection (bacteraemia) is traditionally treated with at least two weeks of IV antibiotics in adults, 3-7 days in children, and often longer for those with complicated disease. The current practice of treating S. aureus bacteraemia (SAB) with prolonged IV antibiotics (rather than oral antibiotics) is based on historical observational research and expert opinion. Prolonged IV antibiotic therapy has significant disadvantages for patients and healthcare systems, and there is growing interest in whether a switch to oral antibiotics following an initial period of IV therapy is a safe alternative for clinically stable patients.

PROTOCOL

The early oral switch (EOS) domain of the S. aureus Network Adaptive Platform (SNAP) trial will assess early switch to oral antibiotics compared with continued IV treatment in clinically stable patients with SAB. The primary endpoint is 90-day all-cause mortality. Hospitalised SAB patients are assessed at platform day 7 +/- 2 (uncomplicated SAB) and day 14 +/-2 (complicated SAB) to determine their eligibility for randomisation to EOS (intervention) or continued IV treatment (current standard of care).

DISCUSSION

Recruitment is occurring to the EOS domain of the SNAP trial. As of August 2023, 21% of all SNAP participants had been randomised to the EOS domain, a total of 264 participants across 77 centres, with an aim to recruit at least 1000 participants. We describe challenges and facilitators to enrolment in this domain to aid those planning similar trials.

Speaking of sepsis: semantics, syntax, and slang

Medical language is in a constant state of evolution. Its grammar and vocabulary are not fixed by rigid rules. The interdisciplinary field of sepsis has become a meeting point for new insights arising from advances in systems biology, epidemiology, mechanistic understandings of disease process and antimicrobial interventions. This convergence has gained from our recent experience of SARS-CoV-2 infection and COVID-19 and possibilities inferred from emerging information technology. Biomedical descriptors have diverged along disciplinary lines creating an unfortunate disconnect between clinical and laboratory-based terminology. The resulting confusion between clinically determined sepsis and laboratory verified bloodstream infection raises practical questions that affect daily operational processes in the ward, clinic and laboratory. There is an urgent need to understand how the clinical sepsis pathway and corresponding clinical laboratory workflow can be better aligned as a single coherent entity. There is also an implicit need to understand how this process should produce actionable information in a timely and orderly manner, and identify residual obselete terminology that has crept into common usage. A widely accepted sepsis epistemology, ontology and heuristic will help us improve our clinical management of sepsis.

The Epidemiological, Clinical, and Microbiological Features of Patients with Burkholderia pseudomallei Bacteraemia-Implications for Clinical Management

Patients with melioidosis are commonly bacteraemic. However, the epidemiological characteristics, the microbiological findings, and the clinical associations of Burkholderia pseudomallei bacteraemia are incompletely defined. All cases of culture-confirmed melioidosis at Cairns Hospital in tropical Australia between January 1998 and June 2023 were reviewed. The presence of bacteraemia was determined and correlated with patient characteristics and outcomes; 332/477 (70%) individuals in the cohort were bacteraemic. In multivariable analysis, immunosuppression (odds ratio (OR) (95% confidence interval (CI)): (2.76 (1.21-6.27), p = 0.02), a wet season presentation (2.27 (1.44-3.59), p < 0.0001) and male sex (1.69 (1.08-2.63), p = 0.02), increased the likelihood of bacteraemia. Patients with a skin or soft tissue infection (0.32 (0.19-0.57), p < 0.0001) or without predisposing factors for melioidosis (0.53 (0.30-0.93), p = 0.03) were less likely to be bacteraemic. Bacteraemia was associated with intensive care unit admission (OR (95%CI): 4.27 (2.35-7.76), p < 0.0001), and death (2.12 (1.04-4.33), p = 0.04). The median (interquartile range) time to blood culture positivity was 31 (26-39) hours. Patients with positive blood cultures within 24 h were more likely to die than patients whose blood culture flagged positive after this time (OR (95%CI): 11.05 (3.96-30.83), p < 0.0001). Bacteraemia portends a worse outcome in patients with melioidosis. Its presence or absence might be used to help predict outcomes in cases of melioidosis and to inform optimal clinical management.

A very rare case of bacteraemia in a 4-year-old girl with osteopetrosis with probable Leuconostoc lactis infection

Leuconostoc lactis (LLac) is a Gram-positive coccus of the family Leuconostocaceae . It can be found in a variety of vegetables and dairy products. LLac is an opportunistic pathogen with intrinsic resistance to vancomycin and teicoplanin. In this case report, we discuss a rare case of LLac-associated bacteraemia in a patient with osteopetrosis. A 4-year-old girl was admitted to the paediatric emergency department with acute fever without other signs. Blood culture revealed an infection with LLac. Using the streptococcus antibiogram, the isolate was resistant to vancomycin, teicoplanin, rifampicin and sulfamethoxazole-trimethoprim but sensitive to β-lactams, gentamicin, streptomycin, azithromycin, clarithromycin, lincomycin, clindamycin and erythromycin. The patient was treated with intravenous ceftriaxone and gentamicin, and subsequently with oral amoxicillin. After a favourable course, she was discharged from the hospital on the 10th day. The modes of transmission and physiopathology of LLac remain unknown. Factors associated with this infection include compromised immunity, previous antibiotic therapy especially with vancomycin, and application of a central venous catheter. In our patient, the risk factors for infection were pancytopenia and multiple transfusions used to treat bone marrow failure. The source of the bacteraemia could have been the cutaneous route, but it could also have been digestive due to the reservoir of the bacteria. LLac is known as an opportunistic bacterium. Further studies on its pathogenesis and other risk factors are needed to understand the true prevalence of this potentially fatal bacterium in compromised individuals, such as the case of our patient.

Disseminated Nocardia farcinica infection associated with bacteraemia and osteomyelitis pubis in an elderly patient

OBJECTIVE

We describe a rare case of a disseminated Nocardia farcinica infection associated with hip osteomyelitis.

METHODS

A 91-year-old female patient was admitted with oedema of her right leg, fever of 38 °C and data consistent with ruptured Baker's cyst. A disseminated Nocardia farcinica infection including bloodstream infection, pneumonia and multiple abscesses along both lower limbs was observed.

RESULTS

After a four-week course of 320 mg/1600 mg/12 h of intravenous trimethoprim/sulfamethoxazole and multiple chirurgic drainages the patient was discharged with oral trimethoprim/sulfamethoxazole. Nevertheless, the patient expired done month after being discharged from the hospital.

CONCLUSIONS

The implementation of a combination of intravenous antibiotics and drainages resulted in an initial improvement in the patient's condition. However, despite these interventions, the patient ultimately passed away probably due to natural causes.

A statistical genomics framework to trace bacterial genomic predictors of clinical outcomes in Staphylococcus aureus bacteremia

Outcomes of severe bacterial infections are determined by the interplay between host, pathogen, and treatments. While human genomics has provided insights into host factors impacting Staphylococcus aureus infections, comparatively little is known about S. aureus genotypes and disease severity. Building on the hypothesis that bacterial pathoadaptation is a key outcome driver, we developed a genome-wide association study (GWAS) framework to identify adaptive mutations associated with treatment failure and mortality in S. aureus bacteremia (1,358 episodes). Our research highlights the potential of vancomycin-selected mutations and vancomycin minimum inhibitory concentration (MIC) as key explanatory variables to predict infection severity. The contribution of bacterial variation was much lower for clinical outcomes (heritability <5%); however, GWASs allowed us to identify additional, MIC-independent candidate pathogenesis loci. Using supervised machine learning, we were able to quantify the predictive potential of these adaptive signatures. Our statistical genomics framework provides a powerful means to capture adaptive mutations impacting severe bacterial infections.

Yersinia pseudotuberculosis bacteraemia with splenic abscesses: a case report

Introduction

Yersinia pseudotuberculosis has been known to cause a variety of clinical manifestations ranging from mild enteric illness to bacteraemia with septic shock and extraintestinal abscesses. Patients with liver disease and iron overload are at risk of more severe disease manifestations.

Case Report

A middle-aged male with chronic alcohol use disorder presented with confusion and jaundice, with ascites and asterixis noted on examination. His blood work was remarkable for neutrophilic leukocytosis, elevated liver enzymes and lactate. An abdominal computed tomography scan revealed splenic microabscesses and a cirrhotic liver. Yersinia pseudotuberculosis was recovered from his blood cultures and he was treated with ceftriaxone following susceptibility results.

Conclusion

Y. pseudotuberculosis should be considered in the differential diagnosis of splenic or other extraintestinal microabscesses particularly in patients with chronic liver disease.

A 24-year longitudinal study of Klebsiella pneumoniae isolated from patients with bacteraemia and urinary tract infections reveals the association between capsular serotypes, antibiotic resistance, and virulence gene distribution

Longitudinal studies on the variations of phenotypic and genotypic characteristics of K. pneumoniae across two decades are rare. We aimed to determine the antimicrobial susceptibility and virulence factors for K. pneumoniae isolated from patients with bacteraemia or urinary tract infection (UTI) from 1999 to 2022. A total of 699 and 1,267 K. pneumoniae isolates were isolated from bacteraemia and UTI patients, respectively, and their susceptibility to twenty antibiotics was determined; PCR was used to identify capsular serotypes and virulence-associated genes. K64 and K1 serotypes were most frequently observed in UTI and bacteraemia, respectively, with an increasing frequency of K20, K47, and K64 observed in recent years. entB and wabG predominated across all isolates and serotypes; the least frequent virulence gene was htrA. Most isolates were susceptible to carbapenems, amikacin, tigecycline, and colistin, with the exception of K20, K47, and K64 where resistance was widespread. The highest average number of virulence genes was observed in K1, followed by K2, K20, and K5 isolates, which suggest their contribution to the high virulence of K1. In conclusion, we found that the distribution of antimicrobial susceptibility, virulence gene profiles, and capsular types of K. pneumoniae over two decades were associated with their clinical source.

A Rare Bacteremia in a Burn Patient: A Case Report of Achromobacter Xylosoxidans and Denitrificans

Achromobacter is a rare bacteria that causes bacteremia in immune-compromised patients. In this case, a 26-year-old male patient with major burns with a positive blood culture for Achromobacter is presented. A rare bacterium, Achromobacter xylosoxidans, and denitrificans, was detected in the blood culture of a patient who was hospitalized due to major burn trauma and had delayed wound healing and had no graft take. After treatment with culture-specific antibiotics, the patients' acute phase reactants decreased, and he was discharged with 100% graft-take. Sepsis is the most common cause of death in major burns. Endogenous and exogenous bacteria cause sepsis. Bacteremia and sepsis are the most important factors affecting wound healing in burn patients. This case shows that rare opportunistic bacteria such as Achromobacter spp. should be considered in major burn patients with delayed wound healing and recurrent graft lysis.

Epidemiology of Group A Streptococcal bacteraemia in Hunter New England Local Health District, 2008 to 2019

Invasive Group A Streptococcal infection (iGAS) is an uncommon but serious infection with Streptococcus pyogenes in a normally sterile body site. Manifestations include bacteraemia, necrotising fasciitis and toxic shock syndrome with attendant serious morbidity and mortality. An increasing incidence of iGAS has been observed in some regions of Australia. iGAS became a nationally notifiable condition from 1 July 2021. To determine if regional incidence has increased, and to identify priority populations, we undertook a retrospective data analysis of Group A Streptococcal (GAS) bacteraemia cases in Hunter New England Local Health District (HNELHD), New South Wales, Australia, from 1 January 2008 to 31 December 2019, as identified by NSW Health Pathology, John Hunter Hospital. A total of 486 cases were identified (age-standardised rate: 4.05 cases per 100,000 population per year). Incidence in HNELHD gradually increased over the study period (adjusted incidence rate ratio: 1.04; 95% confidence interval: 1.01-1.07) and was significantly higher in children under 5 years of age; in adults over 70 years of age; in males; and in First Nations peoples. A significant peak occurred in 2017 (9.00 cases per 100,000 population), the cause of which remains unclear. GAS bacteraemia is uncommon but severe, and incidence in HNELHD has slowly increased. Public health and clinical guidelines must address the needs of priority populations, which include young children, older adults and First Nations peoples. Routine surveillance and genomic analysis will help improve our understanding of iGAS and inform best public health management.

Community-Acquired, Bacteraemic Acinetobacter Baumannii Pneumonia: A Retrospective Review of Cases in Tropical Queensland, Australia

BACKGROUND

Community-acquired Acinetobacter pneumonia (CAAP) typically presents with rapid progression to fulminant disease and is complicated by high mortality. Australian epidemiological studies are few.

METHODS

We conducted a retrospective study on bacteraemic cases of CAAP over twenty years (2000-2019) in North Queensland. Cases were selected on microbiologic, clinical, and radiographic parameters. Data on patient demographics were obtained, along with microbial, antibiotic, mortality and climatic data.

RESULTS

28 cases of CAAP were included. Nineteen (67.9%) were male, twenty-three (82.1%) were Indigenous Australians, and the mean age was 45.9 years. Most presentations were of moderate to severe pneumonia (25/28 (89.3%)). Furthermore, 90% of cases had two or more risk factors. The strongest risk factors for CAAP were alcohol excess and tobacco use. No statistically significant difference in presenting severity, ICU admission or mortality was seen between dry- and wet-season disease. Dry-season disease accounted for 35.7% of cases. Overall mortality was 28.6%. Early use of meropenem or gentamicin reduced mortality irrespective of presenting severity (mortality 17.6%) Non-targeted antibiotic therapy was associated with a non-significant difference in mortality of 44.4%.

CONCLUSIONS

Early administration of targeted antibiotics can mitigate a high mortality rate. The choice of antibiotic therapy for community-acquired pneumonia should be based on severity, risk factors and clinical suspicion of CAAP rather than seasonality.

Antimicrobial resistance and clonality of Staphylococcus aureus causing bacteraemia in children admitted to the Manhiça District Hospital, Mozambique, over two decades

BACKGROUND

Staphylococcus aureus is one of the main causes of bacteraemia, associated with high mortality, mainly due to the occurrence of multidrug resistant (MDR) strains. Data on antibiotic susceptibility and genetic lineages of bacteraemic S. aureus are still scarce in Mozambique. The study aims to describe the antibiotic susceptibility and clonality of S. aureus isolated from blood cultures of children admitted to the Manhiça District Hospital over two decades (2001-2019).

METHODS

A total of 336 S. aureus isolates detected in blood cultures of children aged <5 years were analyzed for antibiotic susceptibility by disk diffusion or minimal inhibitory concentration, and for the presence of resistance determinants by PCR. The clonality was evaluated by SmaI-PFGE, spa typing, and MLST. The SCCmec element was characterized by SCCmec typing.

RESULTS

Most S. aureus (94%, 317/336) were resistant to at least one class of antibiotics, and one quarter (25%) showed a MDR phenotype. High rates of resistance were detected to penicillin (90%) and tetracycline (48%); followed by erythromycin/clindamycin (25%/23%), and co-trimoxazole (11%), while resistance to methicillin (MRSA strains) or gentamicin was less frequent (≤5%). The phenotypic resistance to distinct antibiotics correlated well with the corresponding resistance determinants (Cohen's κ test: 0.7-1.0). Molecular typing revealed highly diverse clones with predominance of CC5 (17%, 58/336) and CC8 (16%), followed by CC15 (11%) and CC1 (11%). The CC152, initially detected in 2001, re-emerged in 2010 and became predominant throughout the remaining surveillance period, while other CCs (CC1, CC5, CC8, CC15, CC25, CC80, and CC88) decreased over time. The 16 MRSA strains detected belonged to clones t064-ST612/CC8-SCCmecIVd (69%, 11/16), t008-ST8/CC8-SCCmecNT (25%, 4/16) and t5351-ST88/CC88-SCCmecIVa (6%, 1/16). Specific clonal lineages were associated with extended length of stay and high in-hospital mortality.

CONCLUSION

We document the circulation of diverse MDR S. aureus causing paediatric bacteraemia in Manhiça district, Mozambique, requiring a prompt recognition of S. aureus bacteraemia by drug resistant clones to allow more targeted clinical management of patients.

A case report of disseminated Streptococcus pneumoniae infection complicated by infective endocarditis, septic arthritis and epidural abscess in an immunocompetent patient

Streptococcus pneumoniae is a highly virulent, vaccine-preventable pathogen which can cause disease on a spectrum from benign to fatal. Apart from pneumonia, it commonly causes septicaemia and meningitis. This case report describes an unusual range of complications in a 53-year-old Caucasian female presenting to a regional hospital, without any risk known factors for severe disease (such as extremes of age, immunodeficiency or co-morbidities). Progressing from an episode of otitis media, her condition rapidly progressed to mastoid sinusitis, septic arthritis, infective endocarditis, epidural abscesses and multiple subcutaneous abscesses. Following quick identification of S. pneumoniae from a positive blood culture, the patient was treated with high-dose benzylpenicillin and ceftriaxone and aggressive source control by surgery, enabling a good clinical recovery.

Bordetella trematum bacteraemia secondary to an empyema in an immunocompromised host: A case report and review of the literature

Introduction

Bordetella trematum infection remains uncommon. More cases of bacteraemia are reported in recent years with the primary infection largely originating from skin and soft tissue sites. Yet, our understanding of its virulence, antibiotic susceptibility profile and treatment is still limited.

Case presentation

Case presentation. We report the first case of B. trematum bacteraemia from a left-sided empyema. An 87-year-old female patient with a past medical history of ischaemic heart disease, diabetes mellitus complicated by nephropathy and locally advanced left breast adenocarcinoma presented with fever, productive cough and shortness of breath. The B. trematum isolates from blood and pleural fluid were identified by MALDI-TOF and 16S rRNA sequencing. Ceftriaxone and azithromycin commenced empirically on admission were switched to piperacillin-tazobactam after 2 days due to lack of clinical improvement. Despite a pleurocentesis and 1 week of piperacillin-tazobactam with microbiological clearance in blood, the patient continued to deteriorate. Decision to withdraw treatment was made in view of the patient's prognosis, and the patient succumbed on the fourteenth day of admission. The isolate was susceptible to piperacillin-tazobactam, imipenem and meropenem but had reduced susceptibility or was non-susceptible to cefuroxime, cefotaxime, ceftazidime, cefepime, the aminoglycosides and fluoroquinolones.

Conclusion

Invasive B. trematum infection is associated with significant mortality. Consensus for antibiotic treatment remains unclear, with limited susceptibility data to support specific antibiotic use. We expect more clinical cases will surface with improved microbial identification systems, as well as enhanced clinical awareness. Standardized and more robust susceptibility work are needed to provide clear recommendations and establish consensus in treating invasive infections.

Extensive remodelling of the cell wall during the development of Staphylococcus aureus bacteraemia

The bloodstream represents a hostile environment that bacteria must overcome to cause bacteraemia. To understand how the major human pathogen Staphylococcus aureus manages this we have utilised a functional genomics approach to identify a number of new loci that affect the ability of the bacteria to survive exposure to serum, the critical first step in the development of bacteraemia. The expression of one of these genes, tcaA, was found to be induced upon exposure to serum, and we show that it is involved in the elaboration of a critical virulence factor, the wall teichoic acids (WTA), within the cell envelope. The activity of the TcaA protein alters the sensitivity of the bacteria to cell wall attacking agents, including antimicrobial peptides, human defence fatty acids, and several antibiotics. This protein also affects the autolytic activity and lysostaphin sensitivity of the bacteria, suggesting that in addition to changing WTA abundance in the cell envelope, it also plays a role in peptidoglycan crosslinking. With TcaA rendering the bacteria more susceptible to serum killing, while simultaneously increasing the abundance of WTA in the cell envelope, it was unclear what effect this protein may have during infection. To explore this, we examined human data and performed murine experimental infections. Collectively, our data suggests that whilst mutations in tcaA are selected for during bacteraemia, this protein positively contributes to the virulence of S. aureus through its involvement in altering the cell wall architecture of the bacteria, a process that appears to play a key role in the development of bacteraemia.

An investigation of household dogs as the source in a case of human bacteraemia caused by Staphylococcus pseudintermedius

Staphylococcus pseudintermedius is a commensal and an opportunistic pathogen in dogs, and is also an opportunistic pathogen in humans. Here we report about a case of bacteraemia with a fatal outcome in a 77-year-old co-morbid male likely caused by a S. pseudintermedius and the investigation into the possible transmission from the two dogs in the patient's household. The two dogs carried the same S. pseudintermedius strain, but this dog strain was unrelated to the strain from the patient. In contrast to the patient strain, the dog strain showed reduced susceptibility to several antibiotics and both dogs had received antibiotic treatment prior to sampling. So, it is conceivable that these treatments can have eliminated the patient's strain between the transmission event and the dog sampling. It is also worth noting that the patient strain was positive for the expA gene, which encodes an exfoliative toxin closely related to the S. aureus exfoliative toxin B. This toxin has been linked to canine pyoderma, but its effect on humans remains unknown. Transmission of S. pseudintermedius was confirmed in the household between the dogs. However, we could not verify that the dogs were the source for the S. pseudintermedius in the patient.

Vancomycin-sensitive Enterococcus faecium bacteraemia - hospital transmission and mortality in a Danish University Hospital

Introduction. The emergence of vancomycin-resistant Enterococcus faecium (VREfm) has left the vancomycin-sensitive E. faecium (VSEfm) strains almost unnoticed.Hypothesis. Molecular characteristics, hospital transmission patterns and clinical impact of VSEfm have changed, and VSEfm is a predictor of VREfm introduction.Aim. We wanted to do a molecular characterization of VSEfm to identify hospital transmissions and links between VSEfm and VREfm, and to investigate the demographics, treatment and impact on mortality of VSEfm bacteraemia.Methodology. VSEfm and VREfm blood culture isolates from Odense University Hospital, Denmark, from 2015 to 2019 were characterized using whole-genome sequencing and core-genome multilocus sequence typing (cgMLST). Clonal shifts and diversity of the VREfm isolates were compared to the VSEfm isolates. Hospital records were used for clinical data and transmission investigation of VSEfm cases.Results. Six-hundred and thirty VSEfm isolates from 599 patients belonged to 42 sequence types (STs) and 131 complex types (CTs) in several clusters. Multiple types were involved in putative transmission, occurring over the entire period. Twenty-seven VREfm bacteraemia cases were included. No correlation between the VSEfm and VREfm clones was identified. The 30 day mortality was 40 %, but only in 6.3 % of the cases, VSEfm bacteraemia was the likely cause of death.Conclusion. The molecular types of VSEfm bacteraemia isolates are changing and diverse. No direct correlation between VSEfm and the introduction of VREfm was found, but widespread hospital transmission indicates a presence of risk factors that could facilitate transmission of other micro-organisms as well. VSEfm bacteraemia is rarely the cause of death, indicating that 30 day mortality does not reflect the cause of death.

A urokinase-associated outbreak of Ralstonia mannitolilytica bloodstream infections in haemodialysis patients in north-eastern Italy, January to April 2023

An outbreak of Ralstonia mannitolilytica bloodstream infections occurred in four hospitals in north-eastern Italy, involving 20 haemodialysis patients with tunnelled central vascular catheter access. We identified as the outbreak source a batch of urokinase vials imported from India contaminated with R. mannitolilytica. Whole genome sequences of the clinical and urokinase strains were highly related, and only urokinase-treated patients were reported with R. mannitolilytica infections (attack rate = 34%; 95% confidence interval: 22.1-47.4). Discontinuation of the contaminated urokinase terminated the outbreak.

Concurrent Staphylococcus aureus bacteraemia in Plasmodium vivax malaria Infection: A report of two cases from western India

Malaria and concurrent bacteraemia cases have been reported globally, mostly in association with Plasmodium falciparum malaria. In comparison, concurrent bacteraemia with Plasmodium vivax infected patients is reported rarely. However, considering unavailability of blood culture testing and widespread community and empirical antibiotic usage in low- and middle-income countries (LMICs), the frequency of bacteraemia and P. vivax co-infection may be much higher. We reported two cases of Staphylococcus aureus bacteraemia with P. vivax malaria infection. Both patients presented with high grade fever and chills with unremarkable systemic examination. Liver enzymes were raised along with inflammatory markers. Simultaneous diagnosis of methicillin sensitive S. aureus bacteraemia was done using automated blood culture, automated identification and sensitivity testing system. P. vivax malaria was confirmed with microscopy, antigen detection test and molecular test. Patients recovered uneventfully with antimalarial drugs and antibiotics.

Ruminococcus gnavus bacteraemia showing morphological diversity on Gram staining: a case report and literature review

Ruminococcus gnavus , a Gram-positive anaerobic coccus, is a common constituent of the human gut microbiota but rarely causes any disease in humans. Herein, we report a case of R. gnavus bacteraemia in an immunocompromised 73-year-old man with sigmoid colon perforation. R. gnavus is usually reported as Gram-positive diplococci or short chains on Gram staining; however, in our patient, a blood isolate showed Gram-positive cocci in long chains, and organisms from an anaerobic subculture showed morphological diversity. This case provides insight into the morphological diversity of R. gnavus , which might help with the recognition of these bacteria in the preliminary identification stage on Gram staining.

Blood cultures with one venipuncture instead of two: a prospective clinical comparative single-center study including patients in the ICU, haematology, and infectious diseases departments

OBJECTIVES

Blood culture is a key method for diagnosing bloodstream infections. In this prospective study, we aimed to investigate whether blood cultures collected with the one-puncture method results in fewer contaminants, i.e. microorganisms from the skin or the environment, and the same detection of relevant pathogens compared to the two-puncture method. Further, we aimed to investigate if the time to blood culture positivity could be useful in evaluating contaminants.

METHODS

Patients planned for blood cultures were asked to participate in the study. From each recruited patient, six blood culture bottles were drawn, bottles 1-4 from the first venipuncture and bottles 5-6 from the second venipuncture. Within each patient, bottles 1-4 were compared to bottles 1, 2, 5, and 6 for contaminants and relevant pathogens. A sub-analysis was conducted on patients admitted to the ICU and those in the haematology department. We also assessed time-to-positivity for coagulase-negative staphylococci.

RESULTS

In the final analysis, 337 episodes from 312 patients were included. Relevant pathogens were identified in 62/337 (18.4%) episodes in both methods. Contaminants were detected in 12 (3.6%) and 19 episodes (5.6%) using the one-puncture and two-puncture method (p = .039), respectively. Corresponding results were observed in the sub-analysis. Notably, relevant coagulase-negative staphylococci demonstrated a shorter time-to-positivity compared to contaminant coagulase-negative staphylococci.

CONCLUSION

Blood cultures obtained using the one-puncture method resulted in significantly fewer contaminants and detected relevant pathogens equally to the two-puncture method. Time-to-positivity may be a useful additive indicator for predicting coagulase-negative staphylococci contamination in blood cultures.

Fosfomycin for Non-Urinary Tract Infections: a systematic review

Introduction

Although fosfomycin is currently approved for treating urinary tract infections, it is increasingly being used as salvage therapy for various infectious syndromes outside the urinary tract. This systematic review evaluates clinical and microbiological cure rates in patients with bacterial infections not restricted to the urinary tract where fosfomycin was used off-label.

Materials and Methods

Articles from two databases (Pubmed and Scopus) were reviewed. The dosage, route, and duration of fosfomycin therapy along with the details of adjunctive antimicrobial agents were noted. The final outcomes captured were clinical or microbiological cures.

Results

A total of 649 articles, not including duplicates, were selected for the title and abstract screening. After title and abstract screening, 102 articles were kept for full-text screening. Of the 102 articles, 23 studies (n=1227 patients) were kept in the final analysis. Of the 1227 patients, 301 (25%) received fosfomycin as monotherapy, and the remaining 926 75%) received fosfomycin in combination with at least one other antimicrobial agent. Most of the patients received intravenous fosfomycin (n=1046, 85%). Staphylococcus spp and Enterobacteriaceae were the most common organisms. The pooled clinical and microbiological cure rates were 75% and 84%, respectively.

Conclusion

Fosfomycin has moderate clinical success in patients with non-urinary tract infections, especially when used with other antimicrobials. Due to the paucity of randomized controlled trials, fosfomycin's use should be limited to situations where no alternatives are supported by better clinical evidence.

Epidemiology and urological pathogenic potential of Aerococcus species in greater Glasgow and Clyde (Descriptive study of Aerococcus urinae in blood culture and urinary samples: clinical importance and potential marker of urinary tract pathology)

Introduction. Aerococcus species in particular A. urinae are increasingly reported as causative agents of bacteraemia, urinary tract infection, sepsis, and endocarditis. We sought to establish the epidemiology of A. urinae in Glasgow hospitals and whether the presence of the organism in clinical isolates could be an indicator of undiagnosed urinary tract pathology.Hypothesis/Gap statement. The knowledge gap among clinical staffs on Aerococcus species as emerging pathogens can be filled by understanding its epidemiology and clinical importance.Aim. Describe the epidemiology and clinical importance of Aerococcus urinae.Methodology. We reviewed positive blood cultures with Aerococcus species (2017-2021) and urinary isolates (2021) in Glasgow hospitals. Data were collected from clinical and laboratory database systems.Results. All 22 positive blood cultures were A. urinae and sensitive to amoxicillin, vancomycin, and ciprofloxacin. The median age was 80.5; the majority was male (18). In total, 15/22 (68 %) were diagnosed with urinary tract infection. Thirteen were treated with amoxicillin. No cases of infective endocarditis were noted. One patient was subsequently diagnosed with bladder carcinoma. All 83 positive urinary isolates in 72 patients were A. urinae. One was resistant to amoxicillin; two to ciprofloxacin; all sensitive to nitrofurantoin and vancomycin. The majority was female (43/83), the median age was 80. The commonest risk factors were underlying malignancy including bladder cancer (5/18), chronic kidney disease (17) and diabetes (16). Clinical data was unavailable in 24 episodes. Of these, 41/59 (69.5 %) were diagnosed with urinary tract infection. One patient was subsequently diagnosed with metastatic renal cancer while bladder wall lesions were identified in three patients, two of whom were waiting for an urology review at the time of study. Thirteen patients (18 %) had 1 year recurrent bacteriuria and three were not treated on initial episode.Conclusion. A. urinae are emerging pathogens and are likely to become more common due to advances in laboratory technologies and an ageing population. Clinical teams should be aware of their urological pathogenic potential and not dismiss them as contaminants. Whether Aerococcus infection is a potential indicator for undiagnosed urinary tract malignancy warrants further studies.

Using an Antibiogram Profile to Improve Infection Control and Rational Antimicrobial Therapy in an Urban Hospital in The Gambia, Strategies and Lessons for Low- and Middle-Income Countries

Antimicrobial resistance is a global health threat and efforts to mitigate it is warranted, thus the need for local antibiograms to improve stewardship. This study highlights the process that was used to develop an antibiogram to monitor resistance at a secondary-level health facility to aid empirical clinical decision making in a sub-Saharan African county. This retrospective cross-sectional descriptive study used 3 years of cumulative data from January 2016 to December 2018. Phenotypic data was manually imputed into WHONET and the cumulative antibiogram constructed using standardized methodologies according to CLSI M39-A4 guidelines. Pathogens were identified by standard manual microbiological methods and antimicrobial susceptibility testing was performed using Kirby-Bauer disc diffusion method according to CLSI M100 guidelines. A total of 14,776 non-duplicate samples were processed of which 1163 (7.9%) were positive for clinically significant pathogens. Among the 1163 pathogens, E. coli (n = 315) S. aureus (n = 232), and K. pneumoniae (n = 96) were the leading cause of disease. Overall, the susceptibility for E. coli and K. pneumoniae from all samples were: trimethoprim-sulfamethoxazole (17% and 28%), tetracycline (26% and 33%), gentamicin (72% and 46%), chloramphenicol (76 and 60%), and ciprofloxacin (69% and 59%), and amoxicillin/clavulanic (77% and 54%) respectively. Extended spectrum beta-lactamase (ESBL) resistance was present in 23% (71/315) vs. 35% (34/96) respectively. S. aureus susceptibility for methicillin was 99%. This antibiogram has shown that improvement in combination therapy is warranted in The Gambia.

Duration of antibiotic treatment and timing of oral switch for bloodstream infections: a survey on the practices of infectious diseases and intensive care physicians

AIM

This study was designed to understand current practice in duration of antibiotic treatment and timing of intravenous (iv) to oral switch for common bacteraemic conditions amongst infectious diseases (ID) and intensive care unit (ICU) physicians.

METHODS

An online survey consisting of 18 questions comprising five common clinical bacteremia scenarios (adapted from the original survey designed by University of Toronto (Toronto, Ontario, Canada)) was conducted amongst Turkish ID and ICU physicians between November 2020 and November 2021.

RESULTS

A total of 236 physicians (76.5 % ID and 17.5 % ICU) responded. The most commonly recommended duration for bacteremia was 14 days (42%), followed by 10 (27%) and 7 (18%) days. The median (IQR) recommended durations were 10 (10-14) days for central venous catheter associated bloodstream infection, 10 (7-14) days for bacteraemic pneumonia, 14 (10-14) days for bacteraemic urinary tract and intraabdominal infections, and 14 days (7-14) for bacteraemic skin and soft tissue infection. Carbapenem resistance but not pathogen type influenced the recommendations. There was not a significant difference in responses for most scenarios between ID and ICU physicians. A switch to oral antibiotics after a median duration of 7 (IQR 5-7) days of iv treatment was considered by 80% of respondents.

CONCLUSION

Prolonged treatment was recommended for most clinical scenarios. Extended iv durations were recommended before oral switch. A presumption that resistant bacterial infections require longer therapy may be responsible for prolonged treatment durations.

Haemodialysis vascular catheter-related blood stream infection: Organism types and clinical outcomes

Catheter-related bloodstream infection (CRBI) is an important complication of catheter use for haemodialysis, but it remains unclear whether clinical outcomes following CRBI are influenced by organism type. This study aims to compare clinical outcomes following CRBI from Gram-positive and non-Gram-positive organisms. This was a retrospective cohort study of patients with kidney failure receiving haemodialysis (HD) via vascular catheters who had a documented episode of CRBI in Western Australia between 2005 and 2018. The associations between organism type, likelihood of hospitalization, catheter removal and death from CRBI were examined using adjusted logistic regression models. There were 111 episodes of CRBI in 99 patients (6.1 episodes per 1000-catheter-days at risk). Of the study cohort, 53 (48%) were male and 38 (34%) identified as Aboriginal or Torres Strait Islander. Gram-positive organisms were identified in 73 (66%) CRBI episodes, most commonly Staphylococcus aureus. Of those with non-Gram-positive CRBI, 9 (24%) were attributed to Pseudomonas aeruginosa. One-hundred and two (92%) episodes of CRBI required hospitalization and 15 (13%) patients died from CRBI. Compared with non-Gram-positive CRBI, Gram-positive CRBI was associated with an increased risk of hospitalization and catheter removal, with adjusted odds ratio of 9.34 (95% CI 1.28-68.03) and 3.47 (95% CI 1.25-9.67), respectively. There was no association between organism type and death from CRBI. Staphylococcus aureus remains the most common organism causing CRBI in HD patients. CRBI is associated with substantial morbidity, particularly CRBI attributed to Gram-positive organisms.

Clinical and Microbiological Features of Fulminant Haemolysis Caused by Clostridium perfringens Bacteraemia: Unknown Pathogenesis

Bacteraemia brought on by Clostridium perfringens has a very low incidence but is severe and fatal in fifty per cent of cases. C. perfringens is a commensal anaerobic bacterium found in the environment and in the intestinal tracts of animals; it is known to produce six major toxins: α-toxin, β-toxin, ε-toxin, and others. C. perfringens is classified into seven types, A, B, C, D, E, F and G, according to its ability to produce α-toxin, enterotoxin, and necrotising enterotoxin. The bacterial isolates from humans include types A and F, which cause gas gangrene, hepatobiliary infection, and sepsis; massive intravascular haemolysis (MIH) occurs in 7-15% of C. perfringens bacteraemia cases, resulting in a rapid progression to death. We treated six patients with MIH at a single centre in Japan; however, unfortunately, they all passed away. From a clinical perspective, MIH patients tended to be younger and were more frequently male; however, there was no difference in the toxin type or genes of the bacterial isolates. In MIH cases, the level of θ-toxin in the culture supernatant of clinical isolates was proportional to the production of inflammatory cytokines in the peripheral blood, suggesting the occurrence of an intense cytokine storm. Severe and systemic haemolysis is considered an evolutionary maladaptation as it leads to the host's death before the bacterium obtains the benefit of iron utilisation from erythrocytes. The disease's extraordinarily quick progression and dismal prognosis necessitate a straightforward and expedient diagnosis and treatment. However, a reliable standard of diagnosis and treatment has yet to be put forward due to the lack of sufficient case analysis.

Differences in the distribution of pathogens and antimicrobial resistance in bloodstream infections in migrants compared with non-migrants in Denmark

BACKGROUND

We wish to study disparities in bloodstream infections in migrants and non-migrants by comparing the distribution of pathogens and their resistance patterns in long-term migrants with that in non-migrants in Denmark.

METHODS

The study is based on a cohort of migrants, who received residency in Denmark between 1993 and 2015 and a control group of non-migrants. The cohort was linked to a database of bloodstream infections from 2000 to 2015 covering two regions in Denmark. First-time bloodstream infections in individuals ≥18 years of age at the time of sampling were included. We calculated odds ratios adjusted for age, sex, year of sampling, comorbidity, and place of acquisition (hospital- or community-acquired).

RESULTS

We identified 4,703 bloodstream infection cases. Family-reunified migrants and refugees had higher odds of Escherichia coli than non-migrants (OR 1.89 95%CI: 1.46-2.44 and OR 1.55 95%CI: 1.25-1.92) and lower odds of Streptococcus pneumoniae (OR 0.38 95%CI: 0.21-0.67 and OR 0.52 95%CI: 0.34-0.81). Differences in pathogen distribution were only prevalent in community-acquired bloodstream infections. Refugees had higher odds of Escherichia coli resistant to piperacillin-tazobactam, ciprofloxacin, and gentamicin compared with non-migrants. Family-reunified migrants had higher odds of Escherichia coli and other Enterobacterales resistant to ciprofloxacin.

CONCLUSIONS

Migrants had a higher proportion of community-acquired bloodstream infections with Escherichia coli as well as higher odds of bloodstream infections with resistant Escherichia coli compared with non-migrants. These novel results are relevant for improving migrant health by focussing on preventing and treating infections especially with Escherichia coli such as urinary tract and abdominal infections.

Bacteremia following different oral procedures: systematic review and meta-analysis

OBJECTIVES

To evaluate the timing, duration and incidence of bacteremia following invasive dental procedures (IDPs) or activities of daily living (ADL).

METHODS

Eight databases were searched for randomized (RCTs) and non-randomized controlled trials (nRCTs) evaluating bacteremia before and after IDPs or ADL in healthy individuals. The risk of bias was assessed by RoB 2.0 and ROBINS-I. For the meta-analysis, the primary outcomes were the timing and duration of bacteremia. The secondary outcome was the incidence of bacteremia, measuring the proportion of patients with bacteremia within 5 minutes after the end of the procedure compared to baseline.

RESULTS

We included 64 nRCTs and 25 RCTs. Peak bacteremia occurred within 5 minutes after the procedure and then decreased over time. Dental extractions showed the highest incidence of bacteremia (62%-66%), followed by scaling and root planing(SRP) (44%-36%) and oral health procedures (OHP) (e.g., dental prophylaxis and dental probing without SRP) (27%-28%). Other ADL (flossing and chewing) (16%) and toothbrushing (8%-26%) resulted in bacteremia as well. The majority of studies had some concerns (RCTs) or moderate risk of bias (nRCTs).

CONCLUSION

Dental extractions, SRP and OHP, are associated with the highest frequency of bacteremia. Toothbrushing, flossing and chewing also caused bacteremia in lower frequency.