Pseudomonas aeruginosa Bloodstream Infections Presenting with Septic Shock in Neutropenic Cancer Patients: Impact of Empirical Antibiotic Therapy

This large, multicenter, retrospective cohort study including onco-hematological neutropenic patients with Pseudomonas aeruginosa bloodstream infection (PABSI) found that among 1213 episodes, 411 (33%) presented with septic shock. The presence of solid tumors (33.3% vs. 20.2%, p < 0.001), a high-risk Multinational Association for Supportive Care in Cancer (MASCC) index score (92.6% vs. 57.4%; p < 0.001), pneumonia (38% vs. 19.2% p < 0.001), and infection due to multidrug-resistant P. aeruginosa (MDRPA) (33.8% vs. 21.1%, p < 0.001) were statistically significantly higher in patients with septic shock compared to those without. Patients with septic shock were more likely to receive inadequate empirical antibiotic therapy (IEAT) (21.7% vs. 16.2%, p = 0.020) and to present poorer outcomes, including a need for ICU admission (74% vs. 10.5%; p < 0.001), mechanical ventilation (49.1% vs. 5.6%; p < 0.001), and higher 7-day and 30-day case fatality rates (58.2% vs. 12%, p < 0.001, and 74% vs. 23.1%, p < 0.001, respectively). Risk factors for 30-day case fatality rate in patients with septic shock were orotracheal intubation, IEAT, infection due to MDRPA, and persistent PABSI. Therapy with granulocyte colony-stimulating factor and BSI from the urinary tract were associated with improved survival. Carbapenems were the most frequent IEAT in patients with septic shock, and the use of empirical combination therapy showed a tendency towards improved survival. Our findings emphasize the need for tailored management strategies in this high-risk population.

Higher rates of cefiderocol resistance among NDM producing Klebsiella bloodstream isolates applying EUCAST over CLSI breakpoints

BACKGROUND

Cefiderocol is generally active against carbapenem-resistant Klebsiella spp. (CRK) with higher MICs against metallo-beta-lactamase producers. There is a variation in cefiderocol interpretive criteria determined by EUCAST and CLSI. Our objective was to test CRK isolates against cefiderocol and compare cefiderocol susceptibilities using EUCAST and CLSI interpretive criteria.

METHODS

A unique collection (n = 254) of mainly OXA-48-like- or NDM-producing CRK bloodstream isolates were tested against cefiderocol with disc diffusion (Mast Diagnostics, UK). Beta-lactam resistance genes and multilocus sequence types were identified using bioinformatics analyses on complete bacterial genomes.

RESULTS

Median cefiderocol inhibition zone diameter was 24 mm (interquartile range [IQR] 24-26 mm) for all isolates and 18 mm (IQR 15-21 mm) for NDM producers. We observed significant variability between cefiderocol susceptibilities using EUCAST and CLSI breakpoints, such that 26% and 2% of all isolates, and 81% and 12% of the NDM producers were resistant to cefiderocol using EUCAST and CLSI interpretive criteria, respectively.

CONCLUSIONS

Cefiderocol resistance rates among NDM producers are high using EUCAST criteria. Breakpoint variability may have significant implications on patient outcomes. Until more clinical outcome data are available, we suggest using EUCAST interpretive criteria for cefiderocol susceptibility testing.

Guidelines for Diagnosis and Management of Infective Endocarditis in Adults: A WikiGuidelines Group Consensus Statement

Importance

Practice guidelines often provide recommendations in which the strength of the recommendation is dissociated from the quality of the evidence.

Objective

To create a clinical guideline for the diagnosis and management of adult bacterial infective endocarditis (IE) that addresses the gap between the evidence and recommendation strength.

Evidence Review

This consensus statement and systematic review applied an approach previously established by the WikiGuidelines Group to construct collaborative clinical guidelines. In April 2022 a call to new and existing members was released electronically (social media and email) for the next WikiGuidelines topic, and subsequently, topics and questions related to the diagnosis and management of adult bacterial IE were crowdsourced and prioritized by vote. For each topic, PubMed literature searches were conducted including all years and languages. Evidence was reported according to the WikiGuidelines charter: clear recommendations were established only when reproducible, prospective, controlled studies provided hypothesis-confirming evidence. In the absence of such data, clinical reviews were crafted discussing the risks and benefits of different approaches.

Findings

A total of 51 members from 10 countries reviewed 587 articles and submitted information relevant to 4 sections: establishing the diagnosis of IE (9 questions); multidisciplinary IE teams (1 question); prophylaxis (2 questions); and treatment (5 questions). Of 17 unique questions, a clear recommendation could only be provided for 1 question: 3 randomized clinical trials have established that oral transitional therapy is at least as effective as intravenous (IV)-only therapy for the treatment of IE. Clinical reviews were generated for the remaining questions.

Conclusions and Relevance

In this consensus statement that applied the WikiGuideline method for clinical guideline development, oral transitional therapy was at least as effective as IV-only therapy for the treatment of IE. Several randomized clinical trials are underway to inform other areas of practice, and further research is needed.

Aspergillus Species Causing Invasive Fungal Disease in Queensland, Australia

BACKGROUND

Aspergillus species are important causes of invasive fungal disease, particularly among those with an impaired immune system. Increasing reports have revealed a rising incidence of antifungal drug resistance among Aspergillus spp., particularly among cryptic species. Understanding local antifungal susceptibility patterns is paramount to delivering optimal clinical care.

METHODS

Aspergillus spp. recovered from clinical specimens between 2000 and 2021 from Pathology Queensland were collected. Aspergillus spp. were identified routinely morphologically, and where there was ambiguity or a lack of sporulation, by sequencing of the internal transcribed spacer (ITS) region. All Aspergillus spp. that underwent antifungal susceptibility testing according to the CLSI M38-A3 method and were recorded and included in the study. Amphotericin B, voriconazole, posaconazole, isavuconazole, micafungin, caspofungin, and anidulafungin were tested. Pathology Queensland services all public healthcare facilities in Queensland, Australia.

RESULTS

236 Aspergillus spp. were identified from clinical specimens during the study period. The most frequent species identified were Aspergillus section Fumigati (n = 119), Aspergillus section Flavi (n = 35), Aspergillus terreus (n = 32) and Aspergillus niger (n = 29). Overall, MIC_50/90 values for voriconazole, posaconazole, itraconazole, and isavuconazole were 0.25/1, 0.25/0.5, 0.25/0.5, and 0.5/2 mg/L respectively. Echinocandins demonstrated low MIC values overall with micafungin and anidulafungin both having an MIC_50/90 of 0.015/0.03 mg/L. A total of 15 cryptic species were identified; high triazole MIC values were observed with a voriconazole MIC_50/90 of 2/8 mg/L. From 2017 to 2021 we observed an increase in incidence of isolates with high voriconazole MIC values. There was no difference in voriconazole MIC values between Aspergillus spp. acquired in North Queensland when compared to Southeast Queensland, Australia.

CONCLUSION

Increasing reports of antifungal resistance among Aspergillus spp. is concerning and warrants further investigation both locally and worldwide. Active surveillance of both the emergence of different Aspergillus spp. and changes in antifungal susceptibility patterns over time is crucial to informing clinicians and treatment guidelines.

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.

High prevalence of ArmA-16S rRNA methyltransferase among aminoglycoside-resistant Klebsiella pneumoniae bloodstream isolates

Introduction. Aminoglycosides are used for the treatment of carbapenemase-producing Klebsiella pneumoniae (CPK) infections. 16S rRNA methyltransferases (RMTs) confer resistance to all aminoglycosides and are often cocarried with NDM.Hypothesis/Gap Statement. There is a dart of studies looking at the aminoglycoside resistance mechanisms for invasive CPK isolates, particularly in OXA-48 endemic settings.Aim. We aimed to determine the prevalence of RMTs and their association with beta lactamases and MLSTs amongst aminoglycoside-resistant CPK bloodstream isolates in an OXA-48 endemic setting.Methodology. CPK isolates (n=181), collected as part of a multicentre cohort study, were tested for amikacin, gentamicin and tobramycin susceptibility using custom-made sensititre plates (GN2XF, Thermo Fisher Scientific). All isolates were previously subjected to whole-genome sequencing. Carbapenemases, RMTs, MLSTs and plasmid incompatibility groups were detected on the assembled genomes.Results. Of the 181 isolates, 109(60 %) were resistant to all three aminoglycosides, and 96 of 109(88 %) aminoglycoside-resistant isolates carried an RMT (85 ArmA, 10 RmtC, 4 RmtF1; three isolates cocarried ArmA and RmtC). Main clonal types associated with ArmA were ST2096 (49/85, 58 %) and ST14 (24/85, 28 %), harbouring mainly OXA-232 and OXA-48 +NDM, respectively. RmtC was cocarried with NDM (5/10) on ST395, and NDM +OXA-48 or NDM +KPC (4/10) on ST14, ST15 and ST16. All RMT producers also carried CTX-M-15, and the majority cocarried SHV-106, TEM-150 and multiple other antibiotic resistance genes. The majority of the isolates harboured a combination of IncFIB, IncH and IncL/M type plasmids. Non-NDM producing isolates remained susceptible to ceftazidime-avibactam.Conclusion. Aminoglycoside resistance amongst CPK bloodstream isolates is extremely common and mainly driven by clonal spread of ArmA carried on ST2096 and ST14, associated with OXA-232 and OXA48 +NDM carriage, respectively.

Treatment strategies for OXA-48-like and NDM producing Klebsiella pneumoniae infections

INTRODUCTION

OXA-48 and NDM are amongst the most prevalent carbapenemase types associated with Klebsiella pneumoniae worldwide, with an increase in their prevalence in recent years. Knowledge on the treatment of carbapenem-resistant Klebsiella pneumoniae (CRKP) comes from KPC-producing CRKP with limited data available for OXA-48-like and NDM producers. Our aim is to review the literature on the treatment of OXA-48-like and NDM-producing CRKP with the goal of providing an update on the available antibiotic treatment strategies, particularly in light of changing carbapenemase epidemiology and increasing antimicrobial resistance.

AREAS COVERED

We reviewed studies looking at the antibiotic treatment and outcome of OXA-48-like and/or NDM-producing CRKP.

EXPERT OPINION

The best available treatment option for OXA-48 producers is ceftazidime-avibactam, where available and when the price permits its use. Colistin remains as the second-line option if in vitro susceptibility is demonstrated with an appropriate method. There is not enough evidence to support the use of meropenem-containing combination therapies for meropenem-resistant OXA-48 producers. Treatment of NDM producers is an unmet need. Ceftazidime-avibactam and aztreonam combination or cefiderocol can be used for NDM producers, where available. Higher cefiderocol MICs against NDM producers is concerning. Aztreonam-avibactam provides hope for the treatment of NDM producers.

Pseudomonas aeruginosa Bloodstream Infections in Patients with Cancer: Differences between Patients with Hematological Malignancies and Solid Tumors

Objectives: To assess the clinical features and outcomes of Pseudomonas aeruginosa bloodstream infection (PA BSI) in neutropenic patients with hematological malignancies (HM) and with solid tumors (ST), and identify the risk factors for 30-day mortality. Methods: We performed a large multicenter, retrospective cohort study including onco-hematological neutropenic patients with PA BSI conducted across 34 centers in 12 countries (January 2006−May 2018). Episodes occurring in hematologic patients were compared to those developing in patients with ST. Risk factors associated with 30-day mortality were investigated in both groups. Results: Of 1217 episodes of PA BSI, 917 occurred in patients with HM and 300 in patients with ST. Hematological patients had more commonly profound neutropenia (0.1 × 109 cells/mm) (67% vs. 44.6%; p < 0.001), and a high risk Multinational Association for Supportive Care in Cancer (MASCC) index score (32.2% vs. 26.7%; p = 0.05). Catheter-infection (10.7% vs. 4.7%; p = 0.001), mucositis (2.4% vs. 0.7%; p = 0.042), and perianal infection (3.6% vs. 0.3%; p = 0.001) predominated as BSI sources in the hematological patients, whereas pneumonia (22.9% vs. 33.7%; p < 0.001) and other abdominal sites (2.8% vs. 6.3%; p = 0.006) were more common in patients with ST. Hematological patients had more frequent BSI due to multidrug-resistant P. aeruginosa (MDRPA) (23.2% vs. 7.7%; p < 0.001), and were more likely to receive inadequate initial antibiotic therapy (IEAT) (20.1% vs. 12%; p < 0.001). Patients with ST presented more frequently with septic shock (45.8% vs. 30%; p < 0.001), and presented worse outcomes, with increased 7-day (38% vs. 24.2%; p < 0.001) and 30-day (49% vs. 37.3%; p < 0.001) case-fatality rates. Risk factors for 30-day mortality in hematologic patients were high risk MASCC index score, IEAT, pneumonia, infection due to MDRPA, and septic shock. Risk factors for 30-day mortality in patients with ST were high risk MASCC index score, IEAT, persistent BSI, and septic shock. Therapy with granulocyte colony-stimulating factor was associated with survival in both groups. Conclusions: The clinical features and outcomes of PA BSI in neutropenic cancer patients showed some differences depending on the underlying malignancy. Considering these differences and the risk factors for mortality may be useful to optimize their therapeutic management. Among the risk factors associated with overall mortality, IEAT and the administration of granulocyte colony-stimulating factor were the only modifiable variables.

Characteristics and outcomes of carbapenemase harbouring carbapenem-resistant Klebsiella spp. bloodstream infections: a multicentre prospective cohort study in an OXA-48 endemic setting

A prospective, multicentre observational cohort study of carbapenem-resistant Klebsiella spp. (CRK) bloodstream infections was conducted in Turkey from June 2018 to June 2019. One hundred eighty-seven patients were recruited. Single OXA-48-like carbapenemases predominated (75%), followed by OXA-48-like/NDM coproducers (16%). OXA-232 constituted 31% of all OXA-48-like carbapenemases and was mainly carried on ST2096. Thirty-day mortality was 44% overall and 51% for ST2096. In the multivariate cox regression analysis, SOFA score and immunosuppression were significant predictors of 30-day mortality and ST2096 had a non-significant effect. All OXA-48-like producers remained susceptible to ceftazidime-avibactam.

Clinical prediction scores and the utility of time to blood culture positivity in stratifying the risk of infective endocarditis in Staphylococcus aureus bacteraemia

Background

Infective endocarditis (IE) complicates up to a quarter of Staphylococcus aureus bacteraemia (SAB) cases. Risk scores predict IE complicating SAB but have undergone limited external validation, especially in community-acquired infections and those who use IV drugs. Addition of the time to positive culture (TTP) may provide incremental risk prognostication.

Objectives

To externally validate risk scores for predicting IE in SAB and assess the incremental value of TTP.

Methods

The modified Duke score was calculated for adults hospitalized with SAB at a major tertiary institution. All patients underwent echocardiography. Sensitivity and specificity of the risk scores for predicting IE were calculated, and the incremental value of TTP was assessed.

Results

One hundred and six cases were analysed and 18 (17%) met definite IE criteria. The optimal TTP to predict IE was 11.5 h (sensitivity 88.9%; specificity 71.6%). The sensitivity of VIRSTA and PREDICT (Predicting risk of endocarditis using a clinical tool) were similar (94.4% for both) and higher than POSITIVE (Prediction Of Staphylococcus aureus Infective endocarditis Time to positivity, IV drug use, Vascular phenomena, pre-Existing heart condition; 77.8%). The receiver-operator characteristic AUCs were VIRSTA 0.83, PREDICT 0.75, POSITIVE 0.89 and TTP 0.85. Adding TTP to VIRSTA (i.e. VIRSTA+) resulted in the highest AUC (0.90), sensitivity (100%) and negative predictive value (100%), albeit with a low specificity (33%).

Conclusions

The VIRSTA and POSITIVE scores were the strongest predictors for IE complicating SAB. The addition of TTP to VIRSTA (VIRSTA+) significantly improved discriminatory value and may be safely used to rationalize echocardiography strategies.

Lower glutamate and GABA levels in auditory cortex of tinnitus patients: a 2D-JPRESS MR spectroscopy study

We performed magnetic resonance spectroscopy (MRS) on healthy individuals with tinnitus and no hearing loss (n = 16) vs. a matched control group (n = 17) to further elucidate the role of excitatory and inhibitory neurotransmitters in tinnitus. Two-dimensional J-resolved spectroscopy (2D-JPRESS) was applied to disentangle Glutamate (Glu) from Glutamine and to estimate GABA levels in two bilateral voxels in the primary auditory cortex. Results indicated a lower Glu concentration (large effect) in right auditory cortex and lower GABA concentration (medium effect) in the left auditory cortex of the tinnitus group. Within the tinnitus group, Glu levels positively correlated with tinnitus loudness measures. While the GABA difference between groups is in line with former findings and theories about a dysfunctional auditory inhibition system in tinnitus, the novel finding of reduced Glu levels came as a surprise and is discussed in the context of a putative framework of inhibitory mechanisms related to Glu throughout the auditory pathway. Longitudinal or interventional studies could shed more light on interactions and causality of Glu and GABA in tinnitus neurochemistry.

An update on cefepime and its future role in combination with novel β-lactamase inhibitors for MDR Enterobacterales and Pseudomonas aeruginosa

Cefepime, a wide-spectrum β-lactam antibiotic, has been in use for the treatment of serious bacterial infections for almost 25 years. Since its clinical development, there has been a dramatic shift in its dosing, with 2 g every 8 hours being preferred for serious infections to optimize pharmacokinetic/pharmacodynamic considerations. The advent of ESBLs has become a threat to its ongoing use, although future coadministration with β-lactamase inhibitors (BLIs) under development is an area of intense study. There are currently four new cefepime/BLI combinations in clinical development. Cefepime/zidebactam is generally active against MBL-producing Enterobacterales and Pseudomonas aeruginosa, in vitro and in animal studies, and cefepime/taniborbactam has activity against KPC and OXA-48 producers. Cefepime/enmetazobactam and cefepime/tazobactam are potential carbapenem-sparing agents with activity against ESBLs. Cefepime/enmetazobactam has completed Phase III and cefepime/taniborbactam is in Phase III clinical studies, where they are being tested against carbapenems or piperacillin/tazobactam for the treatment of complicated urinary tract infections. While these combinations are promising, their role in the treatment of MDR Gram-negative infections can only be determined with further clinical studies.

Completing the Picture-Capturing the Resistome in Antibiotic Clinical Trials

Despite the accepted dogma that antibiotic use is the largest contributor to antimicrobial resistance (AMR) and human microbiome disruption, our knowledge of specific antibiotic-microbiome effects remains basic. Detection of associations between new or old antimicrobials and specific AMR burden is patchy and heterogeneous. Various microbiome analysis tools are available to determine antibiotic effects on microbial communities in vivo. Microbiome analysis of treatment groups in antibiotic clinical trials, powered to measure clinically meaningful endpoints would greatly assist the antibiotic development pipeline and clinician antibiotic decision making.

PRO: Carbapenems should be used for ALL infections caused by ceftriaxone-resistant Enterobacterales

Ceftriaxone resistance in the Enterobacterales is typically the result of production of ESBLs or AmpC β-lactamases. The genes encoding these enzymes are often co-located with other antibiotic resistance genes leading to resistance to aminoglycosides, quinolones and trimethoprim/sulfamethoxazole. Carbapenems are stable to ESBLs and AmpC giving them reliable in vitro activity against producers of these β-lactamases. In contrast, piperacillin/tazobactam and amoxicillin/clavulanate are compromised by co-production of OXA-1, which is not inhibited by tazobactam or clavulanate. These in vitro findings provide an explanation for the MERINO trial outcomes, where 3.7% (7/191) randomized to meropenem died compared with 12.3% (23/187) randomized to piperacillin/tazobactam as definitive treatment of bloodstream infection due to ceftriaxone-resistant organisms. No randomized trials have yet put cefepime and carbapenems head to head, but some observational studies have shown worse outcomes with cefepime. We argue that carbapenems are the antibiotics of choice for ceftriaxone-resistant Enterobacterales.

Achromobacter Infections and Treatment Options

Achromobacter is a genus of nonfermenting Gram-negative bacteria under order Burkholderiales Although primarily isolated from respiratory tract of people with cystic fibrosis, Achromobacter spp. can cause a broad range of infections in hosts with other underlying conditions. Their rare occurrence and ever-changing taxonomy hinder defining their clinical features, risk factors for acquisition and adverse outcomes, and optimal treatment. Achromobacter spp. are intrinsically resistant to several antibiotics (e.g., most cephalosporins, aztreonam, and aminoglycosides), and are increasingly acquiring resistance to carbapenems. Carbapenem resistance is mainly caused by multidrug efflux pumps and metallo-β-lactamases, which are not expected to be overcome by new β-lactamase inhibitors. Among the other new antibiotics, cefiderocol, and eravacycline were used as salvage therapy for a limited number of patients with Achromobacter infections. In this article, we aim to give an overview of the antimicrobial resistance in Achromobacter species, highlighting the possible place of new antibiotics in their treatment.

Limits of the social-benefit motive among high-risk patients: a field experiment on influenza vaccination behaviour

Background

Influenza vaccine uptake remains low worldwide, inflicting substantial costs to public health. Messages promoting social welfare have been shown to increase vaccination intentions, and it has been recommended that health professionals communicate the socially beneficial aspects of vaccination. We provide the first test whether this prosocial vaccination hypothesis applies to actual vaccination behaviour of high-risk patients.

Methods

In a field experiment at a tertiary care public hospital in Istanbul, Turkey, we compare the effects of two motivational messages for promoting vaccination. Using a between-subjects single-blind experimental design patients were randomly assigned to frames emphasizing the vaccine’s benefits to self (n = 125) or social benefits (n = 119). Free influenza vaccination was offered to each patient.

Results

Among 222 patients who were not vaccinated for the season prior to the study (72% medically assessed to be at high risk), 42% in the self-benefit frame chose to receive a vaccination compared with 34% in the social-benefits frame, but the difference was not statistically significant (aOR = 1.63, 95% CI 0.90 to 2.95, p = 0.108). Reasons for vaccination focused primarily on self-benefit (67%) rather than social-benefit (5%). Exploratory analysis showed that the effect of messages depended on patient perception of risk group membership (aOR_High / aOR_Low = 5.59, 95% CI 1.30 to 24.05, p = 0.021). In particular, emphasis on self-benefit was more influential among patients who perceived themselves to be in the risk group (aOR = 6.22, 95% CI 1.69 to 22.88, p = 0.006).

Conclusions

In contrast to the literature observing intentions of low-risk populations, we found no evidence that social-benefit motivates actual vaccination behaviour among a high-risk patient population. Instead, those who self-categorize as being in the high risk group are more motivated by the self-benefit message. Our results suggest that a stratified approach can improve coverage: even if an emphasis on social-benefit could be effective among low-risk groups, an emphasis on self-benefit holds more promise for increasing vaccination in medical organizational settings where high-risk groups are prevalent.

Trial registration

ClinicalTrials.gov NCT04230343 Retrospectively registered on the 13th January 2020.

Impact of antibiotic resistance on outcomes of neutropenic cancer patients with Pseudomonas aeruginosa bacteraemia (IRONIC study): study protocol of a retrospective multicentre international study

INTRODUCTION

Pseudomonas aeruginosa (PA) has historically been one of the major causes of severe sepsis and death among neutropenic cancer patients. There has been a recent increase of multidrug-resistant PA (MDRPA) isolates that may determine a worse prognosis, particularly in immunosuppressed patients. The aim of this study is to establish the impact of antibiotic resistance on the outcome of neutropenic onco-haematological patients with PA bacteraemia, and to identify the risk factors for MDRPA bacteraemia and mortality.

METHODS AND ANALYSIS

This is a retrospective, observational, multicentre, international study. All episodes of PA bacteraemia occurring in neutropenic onco-haematological patients followed up at the participating centres from 1 January 2006 to 31 May 2018 will be retrospectively reviewed. The primary end point will be overall case-fatality rate within 30 days of onset of PA bacteraemia. The secondary end points will be to describe the following: the incidence and risk factors for multidrug-resistant and extremely drug-resistant PA bacteraemia (by comparing the episodes due to susceptible PA with those produced by MDRPA), the efficacy of ceftolozane/tazobactam, the rates of persistent bacteraemia and bacteraemia relapse and the risk factors for very early (48 hours), early (7 days) and overall (30 days) case-fatality rates.

ETHICS AND DISSEMINATION

The Clinical Research Ethics Committee of Bellvitge University Hospital approved the protocol of the study at the primary site. To protect personal privacy, identifying information of each patient in the electronic database will be encrypted. The processing of the patients' personal data collected in the study will comply with the Spanish Data Protection Act of 1998 and with the European Directive on the privacy of data. All data collected, stored and processed will be anonymised. Results will be reported at conferences and in peer-reviewed publications.

Predictors of fatality in influenza A virus subtype infections among inpatients in the 2015-2016 season

BACKGROUND

Infection with the influenza A virus can cause severe disease and mortality. The effect of the different subtypes of influenza on morbidity and mortality is not yet known in Turkey. The aim of this study was to describe the predictors of fatality related to influenza A infection among hospitalized patients in Istanbul during the 2015-2016 influenza season, and to detail the differences between infections caused by H3N2 and H1N1.

METHODS

This was a multicenter study performed by the Istanbul Respiratory Infections Study Group of The Turkish Society of Clinical Microbiology and Infectious Diseases (KLİMİK), among patients hospitalized for influenza in Istanbul during the 2015-2016 influenza season.

RESULTS

A total of 222 patients hospitalized with laboratory-confirmed influenza during the 2015-2016 season were included in the study, of whom 25 (11.2%) died. The fatality rate was significantly higher among patients older than 65 years of age and those with chronic heart and kidney diseases (p<0.001), chronic neurological diseases (p=0.009), and malignancies (p=0.021). Thrombocyte counts were lower in those who died than in those who survived (p<0.004). The median alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, creatinine phosphokinase, and C-reactive protein levels were higher among fatal cases. In the multivariate analysis for the prediction of fatality, being >65years old (odds ratio (OR) 6.9, 95% confidence interval (CI) 2.07-23.08, p=0.002), being infected with influenza A(H3N2) (OR 4.2, 95% CI 1.27-14.38, p=0.019), and a 1-day delay in antiviral use (OR 1.28, 95% CI 1.01-1.63, p=0.036) were found to be associated with an increased likelihood of fatality.

CONCLUSIONS

The case fatality rate of influenza A(H3N2) was significantly higher than that of influenza A(H1N1). Detection of the infection, allowing the opportunity for the early use of antiviral agents, was found to be important for the prevention of fatality. The vaccination should be prioritized for at-risk groups.

New Treatment Options against Carbapenem-Resistant Acinetobacter baumannii Infections

Carbapenem-resistant Acinetobacter baumannii (CRAB) is a perilous nosocomial pathogen causing substantial morbidity and mortality. Current treatment options for CRAB are limited and suffer from pharmacokinetic limitations, such as high toxicity and low plasma levels. As a result, CRAB is declared as the top priority pathogen by the World Health Organization for the investment in new drugs. This urgent need for new therapies, in combination with faster FDA approval process, accelerated new drug development and placed several drug candidates in the pipeline. This article reviews available information about the new drugs and other therapeutic options focusing on agents in clinical or late-stage preclinical studies for the treatment of CRAB, and it evaluates their expected benefits and potential shortcomings.

The outcome of revision hip arthroplasty in patients older than age 80 years: complications and social outcome of different risk groups

Between December 1995 and June 1996, we reviewed 53 consecutive patients who were at least 80 years old and had undergone a revision of a hip prosthesis between June 1988 and June 1995. Three patients (6%) had died after the operation in the hospital. Thirty-five patients were still alive with a mean follow-up of 4.0 years (range, 1.0-7.3 years). At follow-up, 15 patients had died, with a mean survival period of 25 months. Thirteen of the 15 (89%) belonged to American Society of Anesthesiologists' (ASA) group 3. Of 50 patients, 40 (80%) returned to their original social environment. Admission to a home for elderly people or to a nursing home was unrelated to the procedure in 9 of 10 cases. Complications occurred in 27 patients (51%). Major complications occurred only in high-risk patients, classified as ASA 3 according to the physical status classification of the ASA.

Classification of pelvic ring injuries

Advances in the operative stabilization of pelvic ring injuries, particularly by the development of special surgical techniques and implants, call for clear indications. These require the thorough analysis of the injury and its classification. Classification systems facilitate communication and the comparison of treatment concepts and results. Although a number of classification systems have been proposed, none of them has found universal acceptance. The following is a proposal for a comprehensive classification of pelvic ring injuries which, at the same time, accommodates the requirements of the AO/ASIF classification guidelines. The proposal is based primarily on radiographic morphology and secondarily on certain deductions made from it pertaining to the pathomechanics of the injury. To accommodate the extremely wide variety of possibilities, an open system was created by dividing the pelvic ring into anterior and posterior ring segments. Lesions of both segments can be freely combined for the definition of any given pelvic ring injury.

[Follow-up and prognosis of neurologic sequelae of pelvic ring fractures with involvement of the sacrum and/or the iliosacral joint]

The extent of neurological lesions following an injury of the pelvic ring is often not initially recognized, as interest is then focused on the treatment of the pelvic ring fracture. Once the fracture has healed, the patient suffers from the sequelae of the neurological injury. Our series of 323 pelvic ring injuries includes 161 sacral fractures and 12 complete disruptions of the sacroiliac joint. Twenty-three patients sustained an injury of the lumbosacral plexus, and 20 patients were examined retrospectively. The different parts of the lumbosacral plexus showed variable recovery potential. An important or complete recovery was noted in 8 of 9 patients suffering from a motor deficit of the lumbar plexus, the obturator nerve, the superior gluteal nerve or the inferior gluteal nerve. Four out of 8 patients with a motor deficit of the sacral plexus had an important or complete improvement. In contrast to these results was the poor recovery of lesions of the lumbosacral trunk. Eight out of 11 patients showed no or only minor recovery, although the pelvic ring was stabilized by operative means in 9 patients. In 2 patients the lumbosacral trunk was directly decompressed by a dorsal approach. In both cases the recovery was complete. In 6 patients the sphincter function was damaged. Recovery was dependent on the localization of the sacral fracture. If the fracture traversed the sacral canal, no neurological improvement was noted.

[Cervico-acetabular impingement after femoral neck fracture]

Six cases of femoral neck-acetabular impingement following fracture of the femoral neck are reported. To our knowledge, this complication has not previously been described in the literature. A bony prominence at the level of the former fracture site following primary or secondary valgus position of the femoral head showed a conflict with the acetabular rim causing pain and limited motion. In four patients this impingement was posterior, between the femoral neck and the acetabulum in extension with external rotation, and in two patients it was anterior in flexion with internal rotation. A detailed description of the symptoms, diagnostic procedures and treatment options is presented.

[Surgical measures in metastatic lesions of the extremities and pelvic bones]

Two factors--generally increased life expectancy with a higher risk of malignant disease and improved survival rates among cancer patients--have led to a steady increase in the incidence of metastatic bone disease over the past 20 years. There is little controversy about the need for ORIF in the case of pathological fractures, but special techniques are necessary to achieve immediate and lasting stability in the presence of frequently extensive bone destruction. Metastatic bone lesions that involve the risk of fracture should preferably be stabilized prophylactically before further treatment in the form of radiation or chemotherapy. Special techniques of composite osteosyntheses for the long bones and particularly for composite reconstructions of acetabular lesions are listed.

[Classification of pelvic girdle injuries]

Advances in the operative stabilization of pelvic ring injuries, particularly through the development of special surgical techniques and implants, call for clear indications. A prerequisite for these is a comprehensive classification system. Correct placement of any injury within such a system requires a thorough analysis of the injury, and at the same time comparisons of different treatment concepts and their results are facilitated. Although a number of classification systems have been proposed, none of them has found universal acceptance. Our own attempt at completeness has resulted in a new classification, which is based primarily on the X-ray morphology and secondarily on certain deductions made from it pertaining to the pathomechanics of the injury. To accommodate the extremely wide variety of possibilities we created an open system by dividing the pelvic ring into an anterior and a posterior ring segment. Lesions of both segments can be freely combined. As in the ASIF classification of fractures, lesions of the posterior pelvic ring segment are divided into three types, and each of these again into three groups. Lesions of the anterior ring segment are classified in subgroups. The principle of increasing severity represented by morphological complexity, the difficulty of treatment, and the prognosis is strictly adhered to. The proposal is based on the analysis of 283 pelvic ring injuries.

Lumbosacral lesions associated with pelvic ring injuries

In pelvic ring injuries, an anterior lesion is usually combined with a lesion of the posterior ring segment. A fracture of the sacrum is the most common type of posterior lesion. Its severity ranges from a stable minimal compression fracture of the ala of the sacrum to a displaced fracture with complete loss of stability. The fracture line commonly involves the first and second sacral foramina, exiting the bone distally through its free border and proximally just lateral to the articular process of S1. This study shows that in a number of cases the proximal fracture line passes through or medial to the articular process of S1. Consequently, displacement of the involved hemipelvis causes no damage to the lumbosacral junction if the fracture line passes lateral to the articular process of S1. However, any displacement of the mobile hemipelvis must injure the lumbosacral junction with the latter fracture pattern if the fracture line passes through or medial to the articular process of S1. We found an injury of the lumbosacral junction in 6% of all of our pelvic ring injuries and in 38% of those with an unstable vertical sacral fracture. One kind of these lesions, the locked dislocation of the L5/S1 joint, was shown to inhibit reduction of a displaced sacral fracture. Furthermore, these lesions may be responsible for some of the lumbosacral pain frequently persisting after pelvic ring injuries.

Pelvic fractures and traumatic lesions of the posterior urethra

We report on the retrospective analysis of 61 traumatic lesions of the posterior urethra in a fractured pelvis. In collaboration with the orthopedic surgeons, 44 cases could be classified with regard to the nature and mechanism of the pelvic fracture. No direct relationship between the structural integrity of the dorsal ring segment and the urological pathology could be established. However, the mechanism of injury in 35/44 cases with pelvic girdle injuries and urethral pathology appears to be a predominantly lateral compression force. Ten of the 44 patients received a surgical stabilization of the fracture and open splinting of the urethra at the same time. An infection in the area of surgery developed in only one of these patients; however, this cleared up completely under antibiotic therapy and closed suction irrigation. The primarily conservative treatment of urethral lesions (27/61) is compared with primary open splinting or reanastomosis (34/61), which we prefer, with regard to the number of reoperations and late results. The joint conclusion of urologists and orthopedic surgeons concerns a primary simultaneous surgical treatment both of the urethral lesion and the pelvic fracture.

Internal fixation technique in pathological fractures of the extremities

More often than not, the standard methods of internal fixation are insufficient to meet the demands of treatment of pathological fractures. In malignant diseases with improved survival rates, durability of the osteosynthesis is needed. The seemingly convenient prosthetic replacement therefore has to be regarded with caution. Good results without complications cannot be expected unless the fixation of the components is in healthy bone. In the younger patient with a curable disease, late complications have to be considered. We describe methods of internal fixation that satisfy these particular requirements, and pertinent clinical examples elucidate the techniques.

Chiari's osteotomy. A note on technique

Direct joint distraction of the hip facilitates the performance of Chiari's osteotomy on a standard operating table as opposed to the classic procedure on the traction table. Some useful modifications of the original technique include a guide wire to control the direction of the osteotomy, insertion of an additional bone graft to provide better anterior coverage of the head, and internal fixation of the osteotomy.