Exclusive Oral Antibiotic Treatment for Hospitalized Community-Acquired Pneumonia: A Post-Hoc Analysis of a Randomized Clinical Trial

OBJECTIVES

In this study, we aimed to assess the efficacy of different ways of administration and types of beta-lactams for hospitalized community-acquired pneumonia (CAP).

METHODS

In this post-hoc analysis of a RCT on patients hospitalized for CAP (PTC trial) comparing 3-day versus 8-day durations of beta-lactams, which concluded to non-inferiority, we included patients who received either amoxicillin-clavulanate (AMC) or third-generation cephalosporin (3GC) regimens, and exclusively either intravenous or oral treatment for the first 3 days (followed by either 5 days of oral placebo or AMC according to randomization). Choice of route and molecule was left to the physician in charge. The main outcome was failure at 15 days after first antibiotic intake, defined as temperature>37.9°C, and/or absence of resolution/improvement of respiratory symptoms, and/or additional antibiotic treatment for any cause. The primary outcome according to route of administration was evaluated through logistic regression. Inverse probability treatment weighting (IPTW) with a propensity score model was used to adjust for non-randomization of treatment route and potential confounders. The difference in failure rates was also evaluated among several sub-populations (AMC versus 3GC treatments, or intravenous versus oral AMC, patients with multi-lobar infection, patients aged ≥ 65 years old, and patients with CURB65 scores of 3-4).

RESULTS

We included 200 patients from the original trial, with 93/200 (46.5%) patients only treated with intravenous treatment and 107/200 (53.5%) patients only treated with oral therapy. Failure rate at Day 15 was not significantly different among patients treated with initial intravenous versus oral treatment (25/93 (26.9%) versus 28/107 (26.2%), aOR 0.973 (95%CI 0.519-1.823), p=0.932). Failure rates at Day 15 were not significantly different among the subgroup populations.

CONCLUSIONS

Among hospitalized patients with CAP, there was no significant difference in efficacy between initial intravenous and exclusive oral treatment.

TRIAL REGISTRATION

This trial is registered with ClinicalTrials.gov, NCT01963442.

Impact of the phenotypic expression of temocillin resistance in Escherichia coli on temocillin efficacy in a murine peritonitis model

BACKGROUND

Temocillin is a narrow spectrum β-lactam active against MDR Enterobacterales. Mechanisms of acquired resistance to temocillin are poorly understood. We analysed resistance mechanisms in clinical isolates of Escherichia coli and evaluated their impact on temocillin efficacy in vitro and in a murine peritonitis model.

METHODS

Two sets of isogenic clinical E. coli strains were studied: a susceptible isolate (MLTEM16S) and its resistant derivative, MLTEM16R (mutation in nmpC porin gene); and temocillin-resistant derivatives of E. coli CFT073: CFT-ΔnmpC (nmpC deletion), CFTbaeS-TP and CFTbaeS-AP (two different mutations in the baeS efflux-pump gene).Fitness cost, time-kill curves and phenotypic expression of resistance were determined. Temocillin efficacy was assessed in a murine peritonitis model.

RESULTS

MICs of temocillin were 16 and 64 mg/L for MLTEM16S and MLTEM16R, respectively, and 8, 128, 256 and 256 mg/L for E. coli-CFT073, CFT-ΔnmpC, CFTbaeS-TP and CFTbaeS-AP, respectively. No fitness cost of resistance was evidenced. All resistant strains showed heteroresistant profiles, except for CFTbaeS-AP, which displayed a homogeneous pattern. In vitro, temocillin was bactericidal against MLTEM16R, CFT-ΔnmpC, CFTbaeS-TP and CFTbaeS-AP at 128, 256, 512 and 512 mg/L, respectively. In vivo, temocillin was as effective as cefotaxime against MLTEM16R, CFT-ΔnmpC and CFTbaeS-TP, but inefficient against CFTbaeS-AP (100% mortality).

CONCLUSIONS

Heteroresistant NmpC porin alteration and active efflux modification do not influence temocillin efficacy despite high MIC values, unfavourable pharmacokinetic/pharmacodynamic conditions and the absence of fitness cost, whereas homogeneously expressed BaeS efflux pump alteration yielding similar MICs leads to temocillin inefficacy. MIC as sole predictor of temocillin efficacy should be used with caution.

Clinical and bacteriological specificities of Escherichia coli bloodstream infections from biliary portal of entries

BACKGROUND

Escherichia coli is frequently responsible for bloodstream infections (BSI). Among digestive BSI, biliary infections appear to be less severe. Respective roles of host factors, bacterial determinants (phylogroups, virulence and antibiotic resistance) and portal of entry on outcome are unknown.

METHODS

Clinical characteristics and prognosis of 770 episodes of E. coli BSI were analyzed and isolates sequenced (Illumina technology) comparing phylogroups, MLST, virulence and resistance gene content. BSI isolates were compared with 362 commensal E. coli from healthy subjects.

RESULTS

Among 770 episodes, 135 were biliary, 156 non-biliary digestive and 479 urinary. Compared to urinary, BSI of digestive origin occurred significantly more in men, comorbid and immunocompromised patients. Digestive portal of entry was significantly associated with septic shock and death. Among digestive infections, patients with biliary infections were dies less (P=0.032), despite comparable initial severity. Biliary E. coli resembled commensals (phylogroup distribution, ST group and few virulence-associated genes) whereas non-biliary digestive and urinary strains carried many virulence-associated genes.

CONCLUSIONS

E. coli strains responsible for biliary infections exhibit commensal characteristics and are associatedd with lower mortality rates, despite similar initial severity than other digestive BSI. Biliary drainage in addition to antibiotics in the management of biliary infections may explain improved outcome.

Prior participation as a standardized patient improves OSCE scores of third-year medical students: A pilot comparative study at Université Paris Cité Medical School

OBJECTIVE

Objective structured clinical examinations (OSCE) are one of the main modalities of skills' assessment of medical students. We aimed to evaluate the educational value of the participation of third-year medical students in OSCE as standardized patients.

METHODS

We conducted a pilot OSCE session where third-year students participated in sixth-year students' OSCE as standardized patients (cases). Their scores in their own subsequent OSCE exams were compared with third-year students who had not participated (controls). Students' perceptions (stress, preparedness, ease) regarding their OSCE were compared with self-administered questionnaires.

RESULTS

A total of 42 students were included (9 cases and 33 controls). Median [IQR] overall score (out of 20 points) obtained by the cases was 17 [16.3-18] versus 14.5 [12.7-16.3] for controls (p < 0.001). Students' perception of their evaluation (difficulty, stress, communication) was not significantly different between cases and controls. Most cases agreed that their participation was beneficial in reducing their stress (67%), increasing their preparedness (78%) and improving their communication skills (100%). All cases agreed that this participation should be offered more widely.

CONCLUSION

Students' participation in OSCE as standardized patients led to better performance on their own OSCE and were considered beneficial. This approach could be more broadly generalized to improve student performance.

Faecal carriage of extended-spectrum β-lactamase-producing Escherichia coli in a remote region of Niger

OBJECTIVE

Whole genome sequencing (WGS) of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-E. coli) in developing countries is lacking. Here we describe the population structure and molecular characteristics of ESBL-E. coli faecal isolates in rural Southern Niger.

METHODS

Stools of 383 healthy participants were collected among which 92.4% were ESBL-Enterobacterales carriers. A subset of 90 ESBL-E. coli containing stools (109 ESBL-E. coli isolates) were further analysed by WGS, using short- and long-reads.

RESULTS

Most isolates belonged to the commensalism-adapted phylogroup A (83.5%), with high clonal diversity. The blaCTX-M-15 gene was the major ESBL determinant (98.1%), chromosome-integrated in approximately 50% of cases, in multiple integration sites. When plasmid-borne, blaCTX-M-15 was found in IncF (57.4%) and IncY plasmids (26.2%). Closely related plasmids were found in different genetic backgrounds. Genomic environment analysis of blaCTX-M-15 in closely related strains argued for mobilisation between plasmids or from plasmid to chromosome.

CONCLUSIONS

Massive prevalence of community faecal carriage of CTX-M-15-producing E. coli was observed in a rural region of Niger due to the spread of highly diverse A phylogroup commensalism-adapted clones, with frequent chromosomal integration of blaCTX-M-15. Plasmid spread was also observed. These data suggest a risk of sustainable implementation of ESBL in community faecal carriage.

The bacterial genetic determinants of Escherichia coli capacity to cause bloodstream infections in humans

Escherichia coli is both a highly prevalent commensal and a major opportunistic pathogen causing bloodstream infections (BSI). A systematic analysis characterizing the genomic determinants of extra-intestinal pathogenic vs. commensal isolates in human populations, which could inform mechanisms of pathogenesis, diagnostic, prevention and treatment is still lacking. We used a collection of 912 BSI and 370 commensal E. coli isolates collected in France over a 17-year period (2000-2017). We compared their pangenomes, genetic backgrounds (phylogroups, STs, O groups), presence of virulence-associated genes (VAGs) and antimicrobial resistance genes, finding significant differences in all comparisons between commensal and BSI isolates. A machine learning linear model trained on all the genetic variants derived from the pangenome and controlling for population structure reveals similar differences in VAGs, discovers new variants associated with pathogenicity (capacity to cause BSI), and accurately classifies BSI vs. commensal strains. Pathogenicity is a highly heritable trait, with up to 69% of the variance explained by bacterial genetic variants. Lastly, complementing our commensal collection with an older collection from 1980, we predict that pathogenicity continuously increased through 1980, 2000, to 2010. Together our findings imply that E. coli exhibit substantial genetic variation contributing to the transition between commensalism and pathogenicity and that this species evolved towards higher pathogenicity.

Antimicrobial for 7 or 14 Days for Febrile Urinary Tract Infection in Men: A Multicenter Noninferiority Double-Blind, Placebo-Controlled, Randomized Clinical Trial

BACKGROUND

The optimal duration of antimicrobial therapy for urinary tract infections (UTIs) in men remains controversial.

METHODS

To compare 7 days to 14 days of total antibiotic treatment for febrile UTIs in men, this multicenter randomized, double-blind. placebo-controlled noninferiority trial enrolled 282 men from 27 centers in France. Men were eligible if they had a febrile UTI and urine culture showing a single uropathogen. Participants were treated with ofloxacin or a third-generation cephalosporin at day 1, then randomized at day 3-4 to either continue ofloxacin for 14 days total treatment, or for 7 days followed by placebo until day 14. The primary endpoint was treatment success, defined as a negative urine culture and the absence of fever and of subsequent antibiotic treatment between the end of treatment and 6 weeks after day 1. Secondary endpoints included recurrent UTI within weeks 6 and 12 after day 1, rectal carriage of antimicrobial-resistant Enterobacterales, and drug-related events.

RESULTS

Two hundred forty participants were randomly assigned to receive antibiotic therapy for 7 days (115 participants) or 14 days (125 participants). In the intention-to-treat analysis, treatment success occurred in 64 participants (55.7%) in the 7-day group and in 97 participants (77.6%) in the 14-day group (risk difference, -21.9 [95% confidence interval, -33.3 to -10.1]), demonstrating inferiority. Adverse events during antibiotic therapy were reported in 4 participants in the 7-day arm and 7 in the 14-day arm. Rectal carriage of resistant Enterobacterales did not differ between both groups.

CONCLUSIONS

A treatment with ofloxacin for 7 days was inferior to 14 days for febrile UTI in men and should therefore not be recommended.

CLINICAL TRIALS REGISTRATION

NCT02424461; Eudra-CT: 2013-001647-32.

Efficacy of vancomycin lock therapy for totally implantable venous access port-related infection due to coagulase-negative staphylococci in 100 patients with cancer

OBJECTIVES

Data on the efficacy of vancomycin catheter lock therapy (VLT) for conservative treatment of totally implantable venous access port-related infections (TIVAP-RI) due to CoNS are scarce. The aim of this study was to evaluate the effectiveness of VLT in the treatment of TIVAP-RI due to CoNS in cancer patients.

METHODS

This prospective, observational, multicentre study included adults with cancer treated with VLT for a TIVAP-RI due to CoNS. The primary endpoint was the success of VLT, defined as no TIVAP removal nor TIVAP-RI recurrence within 3 months after initiation of VLT. The secondary endpoint was 3 month mortality. Risk factors for VLT failure were also analysed.

RESULTS

One hundred patients were included [men 53%, median age 63 years (IQR 53-72)]. Median duration of VLT was 12 days (IQR 9-14). Systemic antibiotic therapy was administered in 87 patients. VLT was successful in 44 patients. TIVAP could be reused after VLT in 51 patients. Recurrence of infection after completion of VLT occurred in 33 patients, among which TIVAP was removed in 27. Intermittent VLT (antibiotic solution left in place in the TIVAP lumen part of the time) was identified as a risk factor for TIVAP-RI recurrence. At 3 months, 26 deaths were reported; 1 (4%) was related to TIVAP-RI.

CONCLUSIONS

At 3 months, success of VLT for TIVAP-RI due to CoNS was low. However, removing TIVAP was avoided in nearly half the patients. Continuous locks should be preferred to intermittent locks. Identifying factors of success is essential to select patients who may benefit from VLT.

Synergistic Activity of Pep16, a Promising New Antibacterial Pseudopeptide against Multidrug-Resistant Organisms, in Combination with Colistin against Multidrug-Resistant Escherichia coli, In Vitro and in a Murine Peritonitis Model

Colistin is a drug of last resort to treat extreme drug-resistant Enterobacterales, but is limited by dose-dependent toxicity and the emergence of resistance. A recently developed antimicrobial pseudopeptide, Pep16, which acts on the cell membrane, may be synergistic with colistin and limit the emergence of resistance. We investigated Pep16 activity against Escherichia coli with varying susceptibility to colistin, in vitro and in a murine peritonitis model. Two isogenic derivatives of E. coli CFT073 (susceptible and resistant to colistin) and 2 clinical isolates (susceptible (B119) and resistant to colistin (Af31)) were used. Pep16 activity, alone and in combination with colistin, was determined in vitro (checkerboard experiments, time-kill curves, and flow cytometry to investigate membrane permeability). Toxicity and pharmacokinetic analyses of subcutaneous Pep16 were performed in mice, followed by the investigation of 10 mg/kg Pep16 + 10 mg/kg colistin (mimicking human concentrations) in a murine peritonitis model. Pep16 alone was inactive (MICs = 32-64 mg/L; no bactericidal effect). A concentration-dependent bactericidal synergy of Pep16 with colistin was evidenced on all strains, confirmed by flow cytometry. In vivo, Pep16 alone was ineffective. When Pep16 and colistin were combined, a significant decrease in bacterial counts in the spleen was evidenced, and the combination prevented the emergence of colistin-resistant mutants, compared to colistin alone. Pep16 synergizes with colistin in vitro, and the combination is more effective than colistin alone in a murine peritonitis by reducing bacterial counts and the emergence of resistance. Pep16 may optimize colistin use, by decreasing the doses needed, while limiting the emergence of colistin-resistant mutants.

A recurrent pleuropneumonia revealing Erdheim-Chester Disease

Erdheim-Chester disease (ECD) is a rare form of L group histiocytosis, accounting for up to 1500 cases to date worldwide, which mainly affects men between their 5th and 7th decade of life. The most frequent manifestations are bone involvement, perirenal infiltration with an evocating appearance of "hairy kidneys", and a "coated aorta" aspect. Lung involvement in ECD is less common and includes pleural infiltration and interstitial lung disease. Herein, we report the case of a 76-year-old woman with recurrent pleuropneumonia revealing ECD.

Real-life temocillin use in Greater Paris area, effectiveness and risk factors for failure in infections caused by ESBL-producing Enterobacterales: a multicentre retrospective study

Background

Temocillin is a β-lactam that is not hydrolysed by ESBLs.

Objectives

To describe the real-life use of temocillin, to assess its effectiveness in infections caused by ESBL-producing Enterobacterales, and to identify risk factors for treatment failure.

Methods

Retrospective multicentric study in eight tertiary care hospitals in the Greater Paris area, including patients who received at least one dose of temocillin for ESBL infections from 1 January to 31 December 2018. Failure was a composite criterion defined within 28 day follow-up by persistence or reappearance of signs of infection, and/or switch to suppressive antibiotic treatment and/or death from infection. A logistic regression with univariable and multivariable analysis was performed to identify risks associated with failure.

Results

Data on 130 infection episodes were collected; 113 were due to ESBL-producing Enterobacterales. Mean age was 65.2 ± 15.7 years and 68.1% patients were male. Indications were mostly urinary tract infections (UTIs) (85.8%), bloodstream infections (11.5%), respiratory tract infections (RTIs) (3.5%) and intra-abdominal infections (3.5%). Bacteria involved were Escherichia coli (49.6%), Klebsiella pneumoniae (44.2%) and Enterobacter cloacae (8.8%). Polymicrobial infections occurred in 23.0% of cases. Temocillin was mostly used in monotherapy (102/113, 90.3%). Failure was found in 13.3% of cases. Risk factors for failure in multivariable analysis were: RTI (aOR 23.3, 95% CI 1.5-358.2) and neurological disease (aOR 5.3, 95% CI 1.5-18.6).

Conclusions

The main use of temocillin was UTI due to ESBL-producing E. coli and K. pneumoniae, with a favourable clinical outcome. The main risk factor for failure was neurological disease.

Contribution of Clinical Metagenomics to the Diagnosis of Bone and Joint Infections

Bone and joint infections (BJIs) are complex infections that require precise microbiological documentation to optimize antibiotic therapy. Currently, diagnosis is based on microbiological culture, sometimes complemented by amplification and sequencing of the 16S rDNA gene. Clinical metagenomics (CMg), that is, the sequencing of the entire nucleic acids in a sample, was previously shown to identify bacteria not detected by conventional methods, but its actual contribution to the diagnosis remains to be assessed, especially with regard to 16S rDNA sequencing. In the present study, we tested the performance of CMg in 34 patients (94 samples) with suspected BJIs, as compared to culture and 16S rDNA sequencing. A total of 94 samples from 34 patients with suspicion of BJIs, recruited from two sites, were analyzed by (i) conventional culture, (ii) 16S rDNA sequencing (Sanger method), and (iii) CMg (Illumina Technology). Two negative controls were also sequenced by CMg for contamination assessment. Based on the sequencing results of negative controls, 414 out of 539 (76.7%) bacterial species detected by CMg were considered as contaminants and 125 (23.2%) as truly present. For monomicrobial infections (13 patients), the sensitivity of CMg was 83.3% as compared to culture, and 100% as compared to 16S rDNA. For polymicrobial infections (13 patients), the sensitivity of CMg was 50% compared to culture, and 100% compared to 16S rDNA. For samples negative in culture (8 patients, 21 samples), CMg detected 11 bacteria in 10 samples from 5 different patients. In 5/34 patients, CMg brought a microbiological diagnosis where conventional methods failed, and in 16/34 patients, CMg provided additional information. Finally, 99 antibiotic resistance genes were detected in 24 patients (56 samples). Provided sufficient genome coverage (87.5%), a correct inference of antibiotic susceptibility was achieved in 8/8 bacteria (100%). In conclusion, our study demonstrated that the CMg provides complementary and potentially valuable data to conventional methods of BJIs diagnosis.

Genome wide association study of Escherichia coli bloodstream infection isolates identifies genetic determinants for the portal of entry but not fatal outcome

Escherichia coli is an important cause of bloodstream infections (BSI), which is of concern given its high mortality and increasing worldwide prevalence. Finding bacterial genetic variants that might contribute to patient death is of interest to better understand infection progression and implement diagnostic methods that specifically look for those factors. E. coli samples isolated from patients with BSI are an ideal dataset to systematically search for those variants, as long as the influence of host factors such as comorbidities are taken into account. Here we performed a genome-wide association study (GWAS) using data from 912 patients with E. coli BSI from hospitals in Paris, France. We looked for associations between bacterial genetic variants and three patient outcomes (death at 28 days, septic shock and admission to intensive care unit), as well as two portals of entry (urinary and digestive tract), using various clinical variables from each patient to account for host factors. We did not find any association between genetic variants and patient outcomes, potentially confirming the strong influence of host factors in influencing the course of BSI; we however found a strong association between the papGII operon and entrance of E. coli through the urinary tract, which demonstrates the power of bacterial GWAS when applied to actual clinical data. Despite the lack of associations between E. coli genetic variants and patient outcomes, we estimate that increasing the sample size by one order of magnitude could lead to the discovery of some putative causal variants. Given the wide adoption of bacterial genome sequencing of clinical isolates, such sample sizes may be soon available.

Activity of the combination of colistin and fosfomycin against NDM-1-producing Escherichia coli with variable levels of susceptibility to colistin and fosfomycin in a murine model of peritonitis

BACKGROUND

Alternative treatments are needed against NDM-1-producing Escherichia coli. Colistin (COL) and fosfomycin (FOS) often remain active in vitro but selection of resistant mutants is frequent if used separately. We determined whether the combination of colistin and fosfomycin may be useful to treat infections with NDM-1-producing E. coli with varying levels of resistance.

METHODS

Isogenic derivatives of E. coli CFT073 with blaNDM-1 and variable levels of resistance to colistin and fosfomycin (CFT073-NDM1, CFT073-NDM1-COL and CFT073-NDM1-FOS, respectively) were used. The combination (colistin + fosfomycin) was tested in vitro and in a fatal peritonitis murine model. Mortality and bacterial loads were determined and resistant mutants detected.

RESULTS

Colistin MICs were 0.5, 16 and 0.5 mg/L and fosfomycin MICs were 1, 1 and 32 mg/L against CFT073-NDM1, CFT073-NDM1-COL and CFT073-NDM1-FOS, respectively. In time-kill curves, combining colistin with fosfomycin was synergistic and bactericidal against CFT073-NDM1 and CFT073-NDM1-FOS, with concentrations of 4× MIC (for both drugs), but not against CFT073-NDM1-COL (concentrations of colistin = 0.5× MIC), due to regrowth with fosfomycin-resistant mutants. Mice died less and bacterial counts were lower in spleen with the combination compared with monotherapy against all strains; the combination prevented selection of resistant mutants except for CFT073-NDM1-COL where fosfomycin-resistant mutants were found in all mice.

CONCLUSIONS

Combining colistin and fosfomycin was beneficial in vitro and in vivo against NDM-1-producing E. coli, even with strains less susceptible to colistin and fosfomycin. However, the combination failed to prevent the emergence of fosfomycin-resistant mutants against colistin-resistant strains. Combining colistin and fosfomycin constitutes an alternative for treatment of NDM-1 E. coli, except against colistin-resistant strains.

Factors Associated With Treatment Failure in Moderately Severe Community-Acquired Pneumonia: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Failure of treatment is the most serious complication in community-acquired pneumonia (CAP).

OBJECTIVE

To assess the potential risk factors for treatment failure in clinically stable patients with CAP.

DESIGN, SETTING, AND PARTICIPANTS

This secondary analysis assesses data from a randomized clinical trial on CAP (Pneumonia Short Treatment [PTC] trial) conducted from December 19, 2013, to February 1, 2018. Data analysis was performed from July 18, 2019, to February 15, 2020. Patients hospitalized at 1 of 16 centers in France for moderately severe CAP who were clinically stable at day 3 of antibiotic treatment were included in the PTC trial and analyzed in the per-protocol trial population.

INTERVENTIONS

Patients were randomly assigned (1:1) on day 3 of antibiotic treatment to receive β-lactam (amoxicillin-clavulanate [1 g/125 mg] 3 times daily) or placebo for 5 extra days.

MAIN OUTCOMES AND MEASURES

The main outcome was failure at 15 days after first antibiotic intake, defined as a temperature greater than 37.9 °C and/or absence of resolution or improvement of respiratory symptoms and/or additional antibiotic treatment for any cause. The association among demographic characteristics, baseline clinical and biological variables available (ie, at the first day of β-lactam treatment), and treatment failure at day 15 among the per-protocol trial population was assessed by univariate and multivariable logistic regressions.

RESULTS

Overall, 310 patients were included in the study; this secondary analysis comprised 291 patients (174 [59.8%] male; mean [SD] age, 69.6 [18.5] years). The failure rate was 26.8%. Male sex (odds ratio [OR], 1.74; 95% CI, 1.01-3.07), age per year (OR, 1.03; 95% CI, 1.01-1.05), Pneumonia Severe Index score (OR, 1.01; 95% CI, 1.00-1.02), the presence of chronic lung disease (OR, 1.85; 95% CI, 1.03-3.30), and creatinine clearance (OR, 0.99; 95% CI, 0.98-1.00) were significantly associated with failure in the univariate analysis. When the Pneumonia Severe Index score was excluded to avoid collinearity with age and sex in the regression model, only male sex (OR, 1.92; 95% CI, 1.08-3.49) and age (OR, 1.02; 95% CI, 1.00-1.05) were associated with failure in the multivariable analysis.

CONCLUSIONS AND RELEVANCE

In this secondary analysis of a randomized clinical trial, among patients with CAP who reached clinical stability after 3 days of antibiotic treatment, only male sex and age were associated with higher risk of failure, independent of antibiotic treatment duration and biomarker levels. Another randomized clinical trial is needed to evaluate the impact of treatment duration in populations at higher risk for treatment failure.

Specificities of acute cholangitis in patients with cancer: a retrospective comparative study of 130 episodes

Pancreatic and biliary duct cancers are increasing causes of acute cholangitis (AC). We retrospectively characterize 81 cancer-associated cholangitis (CAC) compared to 49 non-cancer-associated cholangitis (NCAC). Clinical and biological presentations were similar. However, in CAC, antibiotic resistance and inadequate empirical antibiotic therapy were more frequent; more patients required ≥ 2 biliary drainages; and mortality at day 28 was higher than in NCAC. Death was associated with initial severity and CAC in a multivariate analysis. Cholangitis associated with pancreatic or biliary duct cancers requires specific empirical antimicrobial therapy; early use of biliary drainage may improve outcomes.

Phylogroup stability contrasts with high within sequence type complex dynamics of Escherichia coli bloodstream infection isolates over a 12-year period

Background

Escherichia coli is the leading cause of bloodstream infections, associated with a significant mortality. Recent genomic analyses revealed that few clonal lineages are involved in bloodstream infections and captured the emergence of some of them. However, data on within sequence type (ST) population genetic structure evolution are rare.

Methods

We compared whole genome sequences of 912 E. coli isolates responsible for bloodstream infections from two multicenter clinical trials that were conducted in the Paris area, France, 12 years apart, in teaching hospitals belonging to the same institution (“Assistance Publique-Hôpitaux de Paris”). We analyzed the strains at different levels of granularity, i.e., the phylogroup, the ST complex (STc), and the within STc clone taking into consideration the evolutionary history, the resistance, and virulence gene content as well as the antigenic diversity of the strains.

Results

We found a mix of stability and changes overtime, depending on the level of comparison. Overall, we observed an increase in antibiotic resistance associated to a restricted number of genetic determinants and in strain plasmidic content, whereas phylogroup distribution and virulence gene content remained constant. Focusing on STcs highlighted the pauci-clonality of the populations, with only 11 STcs responsible for more than 73% of the cases, dominated by five STcs (STc73, STc131, STc95, STc69, STc10). However, some STcs underwent dramatic variations, such as the global pandemic STc131, which replaced the previously predominant STc95. Moreover, within STc131, 95 and 69 genomic diversity analysis revealed a highly dynamic pattern, with reshuffling of the population linked to clonal replacement sometimes coupled with independent acquisitions of virulence factors such as the pap gene cluster bearing a papGII allele located on various pathogenicity islands. Additionally, STc10 exhibited huge antigenic diversity evidenced by numerous O:H serotype/fimH allele combinations, whichever the year of isolation.

Conclusions

Altogether, these data suggest that the bloodstream niche is occupied by a wide but specific phylogenetic diversity and that highly specialized extra-intestinal clones undergo frequent turnover at the within ST level. Additional worldwide epidemiological studies overtime are needed in different geographical and ecological contexts to assess how generalizable these data are.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-021-00892-0.

Discontinuing β-lactam treatment after 3 days for patients with community-acquired pneumonia in non-critical care wards (PTC): a double-blind, randomised, placebo-controlled, non-inferiority trial

BACKGROUND

Shortening the duration of antibiotic therapy for patients admitted to hospital with community-acquired pneumonia should help reduce antibiotic consumption and thus bacterial resistance, adverse events, and related costs. We aimed to assess the need for an additional 5-day course of β-lactam therapy among patients with community-acquired pneumonia who were stable after 3 days of treatment.

METHODS

We did this double-blind, randomised, placebo-controlled, non-inferiority trial (the Pneumonia Short Treatment [PTC]) in 16 centres in France. Adult patients (aged ≥18 years) admitted to hospital with moderately severe community-acquired pneumonia (defined as patients admitted to a non-critical care unit) and who met prespecified clinical stability criteria after 3 days of treatment with β-lactam therapy were randomly assigned (1:1) to receive β-lactam therapy (oral amoxicillin 1 g plus clavulanate 125 mg three times a day) or matched placebo for 5 extra days. Randomisation was done using a web-based system with permuted blocks with random sizes and stratified by randomisation site and Pneumonia Severity Index score. Participants, clinicians, and study staff were masked to treatment allocation. The primary outcome was cure 15 days after first antibiotic intake, defined by apyrexia (temperature ≤37·8°C), resolution or improvement of respiratory symptoms, and no additional antibiotic treatment for any cause. A non-inferiority margin of 10 percentage points was chosen. The primary outcome was assessed in all patients who were randomly assigned and received any treatment (intention-to-treat [ITT] population) and in all patients who received their assigned treatment (per-protocol population). Safety was assessed in the ITT population. This study is registered with ClinicalTrials.gov, NCT01963442, and is now complete.

FINDINGS

Between Dec 19, 2013, and Feb 1, 2018, 706 patients were assessed for eligibility, and after 3 days of β-lactam treatment, 310 eligible patients were randomly assigned to receive either placebo (n=157) or β-lactam treatment (n=153). Seven patients withdrew consent before taking any study drug, five in the placebo group and two in the β-lactam group. In the ITT population, median age was 73·0 years (IQR 57·0-84·0) and 123 (41%) of 303 participants were female. In the ITT analysis, cure at day 15 occurred in 117 (77%) of 152 participants in the placebo group and 102 (68%) of 151 participants in the β-lactam group (between-group difference of 9·42%, 95% CI -0·38 to 20·04), indicating non-inferiority. In the per-protocol analysis, 113 (78%) of 145 participants in the placebo treatment group and 100 (68%) of 146 participants in the β-lactam treatment group were cured at day 15 (difference of 9·44% [95% CI -0·15 to 20·34]), indicating non-inferiority. Incidence of adverse events was similar between the treatment groups (22 [14%] of 152 in the placebo group and 29 [19%] of 151 in the β-lactam group). The most common adverse events were digestive disorders, reported in 17 (11%) of 152 patients in the placebo group and 28 (19%) of 151 patients in the β-lactam group. By day 30, three (2%) patients had died in the placebo group (one due to bacteraemia due to Staphylococcus aureus, one due to cardiogenic shock after acute pulmonary oedema, and one due to heart failure associated with acute renal failure) and two (1%) in the β-lactam group (due to pneumonia recurrence and possible acute pulmonary oedema).

INTERPRETATION

Among patients admitted to hospital with community-acquired pneumonia who met clinical stability criteria, discontinuing β-lactam treatment after 3 days was non-inferior to 8 days of treatment. These findings could allow substantial reduction of antibiotic consumption.

FUNDING

French Ministry of Health.

Temocillin as an alternative treatment for acute bacterial cholangitis: a retrospective microbiology susceptibility-based study of 140 episodes

With rising antibiotic resistance, alternatives to carbapenems are needed for acute cholangitis (AC). Temocillin reaches high biliary concentrations with limited impact on microbiota. We retrospectively included 140 AC episodes and assessed the efficacy of temocillin using microbiology susceptibility testing from blood cultures. Considering all bacteria collected by episode, resistance to temocillin, PIP/TAZ and 3GC occurred in 27/140 (26%), 32 (22.8%) and 31 (22%) episodes, respectively (p = 0.7). After documentation, temocillin could have spared PIP/TAZ or carbapenems in 14/26 and 4/11 episodes. Temocillin may constitute an alternative treatment after microbiological documentation by sparing carbapenems and/or PIP/TAZ, but not as an empirical therapeutic option.

Novel Chromosomal Mutations Responsible for Fosfomycin Resistance in Escherichia coli

Fosfomycin resistance in Escherichia coli results from chromosomal mutations or acquisition of plasmid-mediated genes. Because these mechanisms may be absent in some resistant isolates, we aimed at decipher the genetic basis of fosfomycin resistance in E. coli. Different groups of isolates were studied: fosfomycin-resistant mutants selected in vitro from E. coli CFT073 (MIC = 1 mg/L) and two groups (wildtype and non-wildtype) of E. coli clinical isolates. Single-nucleotide allelic replacement was performed to confirm the implication of novel mutations into resistance. Induction of uhpT expression by glucose-6-phosphate (G6P) was assessed by RT-qPCR. The genome of all clinical isolates was sequenced by MiSeq (Illumina). Two first-step mutants were obtained in vitro from CFT073 (MICs, 128 mg/L) with single mutations: G469R in uhpB (M3); F384L in uhpC (M4). Second-step mutants (MICs, 256 mg/L) presented additional mutations: R282V in galU (M7 from M3); Q558^∗ in lon (M8 from M4). Introduction of uhpB or uhpC mutations by site-directed mutagenesis conferred a 128-fold increase in fosfomycin MICs, whereas single mutations in galU or lon were only responsible for a 2-fold increase. Also, these mutations abolished the induction of uhpT expression by G6P. All 14 fosfomycin-susceptible clinical isolates (MICs, 0.5-8 mg/L) were devoid of any mutation. At least one genetic change was detected in all but one fosfomycin-resistant clinical isolates (MICs, 32 - >256 mg/L) including 8, 17, 18, 5, and 8 in uhpA, uhpB, uhpC, uhpT, and glpT genes, respectively. In conclusion, novel mutations in uhpB and uhpC are associated with fosfomycin resistance in E. coli clinical isolates.

Improved clinical communication OSCE scores after simulation-based training: Results of a comparative study

OBJECTIVES

Simulation-based training (SBT) is increasingly used to teach clinical patient-doctor communication skills (CS) to medical students. However, the long-lasting impact of this training has been poorly studied.

METHODS

In this observational study we included all fourth-year undergraduate medical students from a French medical school who undertook a CS objective structured clinical examination (OSCE) and who answered a post-examination survey. OSCE scores and students' feedback were compared by whether students had received a specific CS-SBT or not 12 months prior to the OSCE.

RESULTS

A total of 173 students were included in the study. Of them, 97 (56%) had followed the CS-SBT before the OSCE. Students who had undergone CS-SBT had significantly higher CS-OSCE scores in the multivariate analysis compared to untrained students (mean score 7.5/10 ±1.1 vs. 7.0/10 ±1.6, respectively, Cohen's d = 0.4, p<0.01). They also tended to experience less nervousness during the OSCE (p = 0.09) and increased motivation to further train in "real-life" internships (p = 0.08). However, they overall expressed a general lack of CS in therapeutic patient education, delivering bad news, and disclosing medical errors.

CONCLUSIONS

Fourth-year medical students who benefited from a CS-SBT 12 months before examination displayed higher CS-OSCE scores than their counterparts.

PRACTICE IMPLICATIONS

These results support the early introduction of practical training to improve communication skills in undergraduate medical curricula. Studies are required to assess the sustainability of this improvement over time and its effect on further real doctor-patient communication.

Metagenomic Characterization of Gut Microbiota of Carriers of Extended-Spectrum Beta-Lactamase or Carbapenemase-Producing Enterobacteriaceae Following Treatment with Oral Antibiotics and Fecal Microbiota Transplantation: Results from a Multicenter Randomized Trial

Background: The R-GNOSIS (Resistance in Gram-Negative Organisms: Studying Intervention Strategies) WP3 study was the first multicenter randomized clinical trial systematically investigating fecal microbiota transplantation (FMT) for intestinal decolonization of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE). Here, we characterized the temporal dynamics of fecal microbiota changes in a sub-cohort of the R-GNOSIS WP3 participants before and after antibiotics/FMT using whole metagenome shotgun sequencing. Methods: We sequenced fecal DNA obtained from 16 ESBL-E/CPE carriers having received oral colistin/neomycin followed by FMT and their corresponding seven donors. Ten treatment-naïve controls from the same trial were included. Fecal samples were collected at baseline (V0), after antibiotics but before FMT (V2) and three times after FMT (V3, V4 and V5). Results: Antibiotic treatment transiently decreased species richness and diversity and increased the abundance of antibiotic resistance determinants (ARDs). Bifidobacterium species, together with butyrate- and propionate-producing species from Lachnospiraceae and Ruminococcaceae families were significantly enriched in post-FMT microbiota of treated carriers. After FMT, the proportion of Enterobacteriaceae was lower compared to baseline but without statistical significance. Conclusions: Combined antibiotic and FMT treatment resulted in enrichment of species that are likely to limit the gut colonization by ESBL-E/CPE.

Pyogenic liver abscess in liver transplant recipient: A warning signal for the risk of recurrence and retransplantation

BACKGROUND

Pyogenic liver abscesses in liver transplant recipients (PLA-LTR) are a rare disease whose specificities compared with PLA in non-transplanted patients (PLA-C) are unknown.

METHODS

A retrospective case-control study was conducted in a French academic hospital from January 1, 2010, to December 31, 2014.

RESULTS

Among 176 patients diagnosed with PLA, 14 were LTR; each case was matched with 3 PLA-C controls by date of PLA diagnosis and pathophysiological mechanism of PLA. Median time from liver transplantation to PLA diagnosis was 34.5 months. Among 14 PLA-LTR, 8/14 (57.1%) had bacteremia and 10/14 (71.4%) had positive PLA cultures. Most commonly isolated bacteria were Enterobacteriaceae (9/14; 64.3%), Enterococcus spp. (4/14; 28.6%), and anaerobic bacteria (3/14; 21.4%). Clinical, radiological, and microbiological characteristics did not significantly differ between PLA-LTR and PLA-C but there was a tendency toward more diabetic patients and a less acute presentation. All but one PLA-LTR were associated with ischemic cholangitis, whereas this was a rare cause among PLA-C (13/14 vs 3/42, respectively, P < .001) among patients with PLA-LTR. In contrast, hepatobiliary neoplasia was rare in PLA-LTR but frequent in PLA-C (1/14 vs 24/42, P = .001). No significant difference was found between PLA-LTR and PLA-C in terms of duration of antibiotic therapy (6.5 and 6 weeks, respectively), PLA drainage rates (10/14 and 26/42, respectively), or mortality at 12 months after PLA diagnosis (2/14 and 5/42, respectively). Recurrence rates within the first year were observed in 6/14 patients (42.9%), and retransplantation was needed in 5/14 (35.7%).

CONCLUSIONS

Occurrence of PLA in LTR is a severe event leading to high risk of recurrence and retransplantation.

Clinical efficacy of hydroxychloroquine in patients with covid-19 pneumonia who require oxygen: observational comparative study using routine care data

OBJECTIVE

To assess the effectiveness of hydroxychloroquine in patients admitted to hospital with coronavirus disease 2019 (covid-19) pneumonia who require oxygen.

DESIGN

Comparative observational study using data collected from routine care.

SETTING

Four French tertiary care centres providing care to patients with covid-19 pneumonia between 12 March and 31 March 2020.

PARTICIPANTS

181 patients aged 18-80 years with documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia who required oxygen but not intensive care.

INTERVENTIONS

Hydroxychloroquine at a dose of 600 mg/day within 48 hours of admission to hospital (treatment group) versus standard care without hydroxychloroquine (control group).

MAIN OUTCOME MEASURES

The primary outcome was survival without transfer to the intensive care unit at day 21. Secondary outcomes were overall survival, survival without acute respiratory distress syndrome, weaning from oxygen, and discharge from hospital to home or rehabilitation (all at day 21). Analyses were adjusted for confounding factors by inverse probability of treatment weighting.

RESULTS

In the main analysis, 84 patients who received hydroxychloroquine within 48 hours of admission to hospital (treatment group) were compared with 89 patients who did not receive hydroxychloroquine (control group). Eight additional patients received hydroxychloroquine more than 48 hours after admission. In the weighted analyses, the survival rate without transfer to the intensive care unit at day 21 was 76% in the treatment group and 75% in the control group (weighted hazard ratio 0.9, 95% confidence interval 0.4 to 2.1). Overall survival at day 21 was 89% in the treatment group and 91% in the control group (1.2, 0.4 to 3.3). Survival without acute respiratory distress syndrome at day 21 was 69% in the treatment group compared with 74% in the control group (1.3, 0.7 to 2.6). At day 21, 82% of patients in the treatment group had been weaned from oxygen compared with 76% in the control group (weighted risk ratio 1.1, 95% confidence interval 0.9 to 1.3). Eight patients in the treatment group (10%) experienced electrocardiographic modifications that required discontinuation of treatment.

CONCLUSIONS

Hydroxychloroquine has received worldwide attention as a potential treatment for covid-19 because of positive results from small studies. However, the results of this study do not support its use in patients admitted to hospital with covid-19 who require oxygen.

1492. Comparison of Acute Cholangitis in Patients With or Without Cancer

Background

Cancer-associated acute cholangitis (CAAC) are becoming more frequent and their characteristics may be changing with the evolution of cancer management. Our aim was to compare clinical, microbiological and outcome characteristics of CAAC to those of cancer-free acute cholangitis (CFAC).

Methods

All consecutive cases of acute cholangitis (AC) from November 2015 to March 2017 were collected retrospectively in a single tertiary care hospital in Clichy, France, specialized in gastroenterology. Hospital stays referred as AC by coding were screened. Patients fulfilling the 2018 Tokyo Guidelines diagnostic criteria for definite AC were included. Data were collected using a standardized form. CAAC were defined as AC that occurred in patients who had active cancer or history of cancer in the five previous years. CFAC were defined as AC in patient who no history of cancer, or in remission for more than 5 years. Comparison was made using Fisher or Student’s t-test. P < 0.05 was considered as significant.

Results

156 episodes of AC in 130 patients were analyzed. 101 had CAAC and 55 had CFAC. Age and sex did not differ (table 1), but CAAC had a higher Charlson’s comorbidity index (4.4 vs. 1.7, P < 0.0001). Despite similar clinical presentation, CAAC had more pronounced cholestasis (Gamma GT 659 vs. 391UI/L; Alkaline phosphatases 526 vs. 309 UI/L; P < 0.0001 for both) and C-reactive protein level (133 vs. 97mg/L, P = 0.008, Table 2). E. coli was more common in CFAC (72.4% vs. 54% of positive blood cultures, P = 0.004). In bile cultures, Enterococci and multi-drug-resistant Gram negatives tended to be more frequent in CAAC than in CFAC (63 vs. 17%, P = 0.07 and 9.1% vs. 4.1%, P = 0.33, Table 2), respectively. CAAC more frequently required drainage (86.1% of cases vs. 43.6% in CFAC (P < 0.0001), including radiological drainage (42.5% vs. 12.5%; P = 0.008) and with multiple sessions (28.7% vs. 8.3%, P < 0.0001, Table 3). Antibiotherapy duration did not differ between the two groups. Despite similar initial severity, only 51.5% of patients with CAAC were alive, without febrile recurrence or other biliary drainage at day 28, vs. 85.5% of patients with CFAC (P < 0.0001, Table 3).

Conclusion

Despite comparable initial clinical presentation, management is more complex and outcome less favorable in CAAC vs. CFAC.

Disclosures

All authors: No reported disclosures.

617. Efficacy of Dimercaptosuccinic Acid (DMSA), a Zinc Chelator, in Combination with Imipenem Against Metallo-β-Lactamase Producing Escherichia coli in a Murine Peritonitis Model

Background

A strategy used by bacterial strains to resist β-lactam antibiotics is the expression of metallo-β-lactamases (MBL) requiring zinc for activity. The use of a zinc chelator may restore carbapenem activity against MBL-producing Enterobacteriaceae. DMSA is a heavy metal chelator approved in humans with a satisfactory safety record. Our objective was to evaluate the activity of DMSA in combination with carbapenems, in vitro and in a fatal murine peritonitis model, against MBL-producing Escherichia coli.

Methods

Isogenic derivatives of wild-type E. coli CFT073 producing the MBL NDM-1, VIM-2, IMP-1, and the serine carbapenemases OXA-48 and KPC-3 were constructed. Minimum inhibitory concentrations (MICs) of imipenem, meropenem, and ertapenem were determined against each strain alone or in combination with DMSA. Mice were infected with E. coli CFT073 or NDM-1 and treated intraperitoneally for 24 hours with imipenem 100 mg/kg every 4 hours, DMSA 200 mg/kg every 4 hours, or both. Mice survival rates and bacterial counts in peritoneal fluid (PF) and spleen were assessed at 24 hours.

Results

In vitro, DMSA in combination with each carbapenem permitted a significant decrease of the MICs against all MBL-producing strains, in a concentration-dependent manner. The maximum effect was found for the NDM-1 strain with a 6- to 8-fold MIC reduction, depending on the carbapenem used. NDM-1 strain became susceptible to carbapenems with concentrations of DMSA ≥6 mM. Increasing zinc concentrations above 1 mg/L (average human plasma concentration) did not alter this effect. No benefit of DMSA was observed against non-MBL strains. In vivo, when used alone, the DMSA regimen was not toxic in uninfected mice and ineffective against NDM-1-infected mice (100% mortality). Combination of imipenem and DMSA significantly reduced bacterial counts in PF and spleen as compared with imipenem alone (P < 0.001), and reduced mortality, although not significantly (11% vs. 37%, respectively, P = 0.12). No benefit of the combination was observed against CFT073.

Conclusion

DMSA is highly effective in vitro in reducing carbapenems MICs against MBL-producing E. coli and appears as a promising strategy in combination with carbapenems for the treatment of NDM-1-related infections.

Disclosures

All authors: No reported disclosures.

Hypervirulent Klebsiella pneumoniae in Cryptogenic Liver Abscesses, Paris, France

Liver abscesses containing hypervirulent Klebsiella pneumoniae have emerged during the past 2 decades, originally in Southeast Asia and then worldwide. We hypothesized that hypervirulent K. pneumoniae might also be emerging in France. In a retrospective, monocentric, cohort study, we analyzed characteristics and outcomes for 199 consecutive patients in Paris, France, with liver abscesses during 2010-2015. We focused on 31 patients with abscesses containing K. pneumoniae. This bacterium was present in most (14/27, 52%) cryptogenic liver abscesses. Cryptogenic K. pneumoniae abscesses were more frequently community-acquired (p<0.00001) and monomicrobial (p = 0.008), less likely to involve cancer patients (p<0.01), and relapsed less often (p<0.01) than did noncryptogenic K. pneumoniae liver abscesses. K. pneumoniae isolates from cryptogenic abscesses belonged to either the K1 or K2 serotypes and had more virulence factors than noncryptogenic K. pneumoniae isolates. Hypervirulent K. pneumoniae are emerging as the main pathogen isolated from cryptogenic liver abscesses in the study area.

Prediction of the intestinal resistome by a three-dimensional structure-based method

The intestinal microbiota is considered to be a major reservoir of antibiotic resistance determinants (ARDs) that could potentially be transferred to bacterial pathogens via mobile genetic elements. Yet, this assumption is poorly supported by empirical evidence due to the distant homologies between known ARDs (mostly from culturable bacteria) and ARDs from the intestinal microbiota. Consequently, an accurate census of intestinal ARDs (that is, the intestinal resistome) has not yet been fully determined. For this purpose, we developed and validated an annotation method (called pairwise comparative modelling) on the basis of a three-dimensional structure (homology comparative modelling), leading to the prediction of 6,095 ARDs in a catalogue of 3.9 million proteins from the human intestinal microbiota. We found that the majority of predicted ARDs (pdARDs) were distantly related to known ARDs (mean amino acid identity 29.8%) and found little evidence supporting their transfer between species. According to the composition of their resistome, we were able to cluster subjects from the MetaHIT cohort (n = 663) into six resistotypes that were connected to the previously described enterotypes. Finally, we found that the relative abundance of pdARDs was positively associated with gene richness, but not when subjects were exposed to antibiotics. Altogether, our results indicate that the majority of intestinal microbiota ARDs can be considered intrinsic to the dominant commensal microbiota and that these genes are rarely shared with bacterial pathogens.

Severe, non specific symptoms in non-typhoidal Salmonella infections in adult patients with sickle cell disease: a retrospective multicentre study

BACKGROUND

Non-typhoidal salmonellosis (NTS) often occurs in children with sickle-cell disease (SCD) and remains a significant cause of mortality in developing countries. However, there is lack of reports on the clinical presentation, outcome and complications of NTS in adults with SCD.

METHODS

We performed a chart review between 2006 and 2016 of adults SCD diagnosed with NTS in 3 referral centers monitoring approximately 3500 SCD adults.

RESULTS

Twenty-three episodes of NTS were diagnosed among 22 SCD adults. Diagnosis was challenging: 65% (n = 15/23) of patients presented with vaso-occlusive crisis (VOC) and 30% had no fever. Isolated serotypes were: ser. Enteritidis (n = 8), ser. Typhimurium (n = 6), others (n = 3). We identified two patterns of infections: (1) bacteremic NTS (n = 15) with (n = 9) or without secondary foci of infections (n = 6); (2) non-bacteremic NTS with extra-intestinal foci of infection (n = 8), including primary bones/joints infections (n = 5). Half of patients with osteo-articular localization (n = 6/13) had a previous history of osteonecrosis (n = 2) or osteomyelitis (n = 4) at the same site. Morbidity was high, 6 patients (26%) were admitted to the intensive care unit, 14 patients (61%) required RBC transfusion for VOC. Half of the episodes (n = 12) required surgery (n = 10) or interventional radiology (n = 2) to control the infection. One patient presented a relapse of NTS bacteraemia one year after the first episode.

CONCLUSIONS

Besides bloodstream infections, clinical presentation of NTS in adults with SCD is non-specific at admission. A triad including bacteraemia, secondary focis of infection and bone localizations was observed in 30% of cases.

Ceftriaxone promotes the emergence of AmpC-overproducing Enterobacteriaceae in gut microbiota from hospitalized patients

Epidemiological data suggest that ceftriaxone may promote the emergence of commensal AmpC-overproducing Enterobacteriaceae because of a high biliary excretion. We tested this hypothesis in hospitalized patients either treated by ceftriaxone alone or receiving no antibiotics. Hospitalized patients with no previous antibiotics or hospitalization in the last 3 months, treated only with ceftriaxone, were prospectively included. For each ceftriaxone-treated patient, a control patient receiving no antibiotics was included. Clinical data and stools were collected at T0 (before antibiotics) and T1 (at the end of ceftriaxone treatment or at discharge) and T2 (3-6 months after T1) for the ceftriaxone-treated patients and at T0 and T1 for control patients. Third-generation cephalosporin-resistant Enterobacteriaceae were detected, identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), and characterized genetically. Clonal relatedness was evaluated by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Fifteen ceftriaxone and 22 control patients were included. Patients' characteristics did not differ. At T0, 2/15 ceftriaxone-treated versus 1/22 control patients carried third-generation cephalosporin-resistant Enterobacteriaceae (p = 0.6). At T1, 4/15 (27%) ceftriaxone-treated patients carried AmpC producers versus 0/22 control patients (p = 0.02). Additionally, two and three subjects carried extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in the ceftriaxone and control groups, respectively (p = 1). At T2, three ceftriaxone-treated patients still carried AmpC-producing Enterobacteriaceae with the same RAPD profile as at T1. In hospitalized subjects with no other selective pressure, treatment by ceftriaxone alone promotes the gut colonization by AmpC-overproducing Enterobacteriaceae in over a quarter of patients, with a persistent carriage after the end of antibiotic exposure. The ecological impact of ceftriaxone should not be underestimated.

Ecological impact of ciprofloxacin on commensal enterococci in healthy volunteers

Background

The ecological impact of ciprofloxacin on commensal enterococci is unknown.

Methods

Forty-eight healthy volunteers received ciprofloxacin from day (D) 0 to D14; stools were collected on D7, D14 and D42. Fluoroquinolone-susceptible and -resistant enterococci (FQ-SE and FQ-RE) were detected and quantified by culture, and identified by MALDI-TOF MS. The relative abundance of FQ-RE over FQ-SE was determined. The genetic basis of fluoroquinolone resistance was deciphered by partial sequencing of gyrA and parC genes. Clonal relatedness was determined by random amplification of polymorphic DNA PCR. Clinical trial no.: NCT00190151.

Results

Enterococci were carried by 47/48 (98%) subjects. Total counts were reduced during ciprofloxacin therapy (4.0 and 3.9 log cfu/g on D7 and D14 versus 5.9 log cfu/g before and 6.9 log cfu/g after treatment; P  < 0.05). Twenty-one out of 48 (44%) carried FQ-RE; among them, 21/21 carried Enterococcus faecium , 19 carried Enterococcus faecalis and 11 carried other species. Five out of 48 (10%) harboured FQ-RE (ciprofloxacin MIC >4 mg/L) before treatment (all E. faecium ), 6 on D7 (3 E. faecium and 3 E. faecalis ), 8 on D14 (4 E. faecium and 4 E. faecalis ) and 10 (21%) on D42 (9 E. faecium and 1 E. faecalis ). The relative abundance of FQ-RE increased from 44% on D0 to 73% and 75% on D7 and D14, respectively. No acquisition of fluoroquinolone resistance among endogenous D0 strains was evidenced. All (14/14) distinct Fluoroquinolone-resistant E. faecalis clones were gyrA / parC double mutants with high-level resistance (ciprofloxacin MIC >64 mg/L). In contrast, 34/35 E. faecium exhibited low-level resistance (ciprofloxacin MIC 4-32 mg/L) with no gyrA / parC mutation, but overexpressed the chromosomal Efm qnr gene. As compared with Fluoroquinolone-susceptible strains, Fluoroquinolone-resistant E. faecium were more frequently ampicillin resistant and Fluoroquinolone-resistant E. faecalis were more highly resistant to gentamicin.

Conclusions

Although intrinsically poorly susceptible to fluoroquinolones, gut populations of enterococci are highly impacted both quantitatively and qualitatively by ciprofloxacin.

Presentation and impact of catheter-associated thrombosis in patients with infected long-term central venous catheters: a prospective bicentric observational study

BACKGROUND

Catheter-associated thrombosis (CAT) in patients with infected long-term central venous catheter (LTCVC) has been poorly studied.

METHODS

We prospectively included patients with infected LTCVC and collected clinical data. Doppler ultrasound was systematically performed to screen for CAT. Outcome (death or infection relapse) was evaluated 12 weeks after infection diagnosis.

RESULTS

90 patients were included and CAT was diagnosed in 27 (30%). Local signs suggesting infection were more frequent in patients with CAT than without (11/27 versus 8/63, p = 0.03). Outcome was similar in patients with and without CAT. However, median duration of antimicrobials was longer (18 versus 14 days, p = 0.02), catheter removal tended to be more frequent (24/27 versus 46/63, p = 0.08), and anticoagulant therapy more often prescribed (17/27 versus 6/63, p < 0.01) in patients with CAT than without. Patients with occlusive thrombosis were more likely to have Staphylococcus aureus infections (4/7 versus 1/17, p = 0.02) and prolonged positivity of blood-cultures (3/7 versus 1/15, p = 0.02), than patients with non-occlusive thrombosis.

CONCLUSION

CAT is associated with local signs suggesting infection. A more aggressive treatment in CAT cases allowed a similar outcome at 12 weeks between patients with and without CAT. Occlusive thrombosis represented a subgroup of patients at risk of delayed clearance of bacteremia.

Comparative dynamics of the emergence of fluoroquinolone resistance in staphylococci from the nasal microbiota of patients treated with fluoroquinolones according to their environment

Fluoroquinolone-resistant staphylococci (FQRS) are primarily selected in the nasal microbiota during fluoroquinolone (FQ) treatment. To gain insight into the dynamics of the emergence of FQRS, 49 hospitalised patients (HPs) and 62 community patients (CPs) treated with FQs were studied. Nasal swabs were collected before (T0), at the end of (T1) and 1 month after (T2) FQ treatment. FQRS were identified by mass spectrometry. Antibiotic resistance was determined. Pre- and post-exposure staphylococci populations were compared phenotypically and by MLST to determine the origin of FQRS. At T0, 33/49 HPs (67%) and 24/62 CPs (39%) carried FQRS (OR=3.3, 95% CI: 1.4-7.9; P<0.001). Among patients with no FQRS at T0, 15/16 HPs (94%) and 16/38 CPs (42%) had FQRS detected at T1 and/or T2 (OR=19.6, 95% CI: 2.5-902; P<0.001). Among FQRS having emerged, co-resistance to meticillin was detected in 87% and 82% of HPs and CPs, respectively. No selection of resistance emerging from the initial microbiota was evidenced. FQRS showed decreased species diversity in favour of Staphylococcus haemolyticus and Staphylococcus epidermidis. As a consequence of FQ treatment, acquisition of FQRS in the nasal microbiota is frequent in the community and almost inevitable in hospitals. Acquisition from extranasal sites prevails. A restriction in species diversity in favour of more pathogenic and resistant species occurs. This highlights the major impact of FQ treatment on nasal microbiota, the role of the ecological environment in the emergence of FQRS, and the high-risk of dissemination of resistant staphylococci.

Impact of fluoroquinolones on human microbiota. Focus on the emergence of antibiotic resistance

The aggregate of microorganisms residing on the surface of the skin, in the oropharynx and in the GI tract, known as the human microbiota, play a major role as natural reservoirs for bacterial resistance to antibiotics. Fluoroquinolones (FQ) are among the most prescribed antibiotics and a major increase in FQ resistance is occurring worldwide. High concentrations of FQ are found in microbial ecosystems explaining their profound effect on the clinically relevant bacteria that compose them. Yet, because of different local pharmacokinetics, distinct selective pressures occur in the different microbiota. Here we review the qualitative and quantitative impact of FQ on the three main human microbiota and their consequences, particularly in terms of emergence of antibiotic resistance. Finally, we review potential actions that could decrease the impact of FQs on microbiota.

Emergence of quinolone resistance in the microbiota of hospitalized patients treated or not with a fluoroquinolone

BACKGROUND

Quinolone resistance is a major global clinical problem. It primarily emerges in microbiota under selective pressure. Studies evaluating the incidence and risk factors for carrying quinolone-resistant bacteria in hospitalized patients treated with fluoroquinolones (FQs) are lacking.

METHODS

We prospectively included hospitalized patients treated with FQs. Nasal, throat and rectal swabs were performed before FQ treatment, at the end of FQ treatment and 30 days later. A 'reference group' of patients not receiving FQs was also included to determine the rates of quinolone resistance acquisition not linked to FQ treatment. Prevalence and incidence of quinolone-resistant strains of nasal coagulase-negative staphylococci (CoNS) and Staphylococcus aureus, pharyngeal α-haemolytic streptococci and faecal Escherichia coli, and risk factors for emergence of quinolone resistance in FQ-treated patients were assessed.

RESULTS

Four-hundred and fifty-one FQ-treated patients were included, as well as 119 subjects in the 'reference group'. Emergence of quinolone resistance occurred in 110/213 (51.6%), 50/336 (14.9%), 53/290 (18.3%) and 46/336 (13.7%) of FQ-treated patients for CoNS, S. aureus, α-haemolytic streptococci and E. coli, respectively, significantly more than for reference patients for CoNS (23/65; P < 0.05), S. aureus (5/91; P < 0.02) and E. coli (4/84; P < 0.05), but not for α-haemolytic streptococci (15/70; P = 0.55). Emergence of resistance was not associated with the type of FQ received, the duration of therapy or the duration of hospital stay, but was associated with host factors such as immunosuppression and altered performance status.

CONCLUSIONS

FQs received during hospitalization account for high rates of emergence of resistance to FQs in clinically relevant bacteria from human microbiota, reflecting the important ecological impact of FQs. Host factors outweighed treatment or hospitalization characteristics as risk factors for carrying quinolone-resistant strains.

Risk factors for invasive pneumococcal disease in HIV-infected adults in France in the highly active antiretroviral therapy era

Invasive pneumococcal diseases remain frequent and severe in HIV-infected subjects. To identify opportunities for prevention, we assessed risk factors of invasive pneumococcal diseases (IPD) in HIV-infected patients over a 10-year period in France. We performed a retrospective case-control study in a reference centre of HIV management in Paris. All HIV-infected patients having suffered from IPD between 2000 and 2011 were included. Control subjects were HIV-infected with no history of IPD or pneumonia, matched by date of diagnosis of HIV with controls. Two controls were randomly selected for each subject. In all, 42 HIV-infected patients presented 44 IPD episodes during the study period and were compared to 84 controls. In the multivariate analysis, patients with IPD were more likely than controls to have a Charlson Comorbidity Index ≥2 (adjusted OR = 7.07, 95% CI 1.99–25.1, p = 0.003), CD4-cell count <200/cells/µL (aOR = 6.93, 95% CI 1.80–26.7, p = 0.005), HIV-RNA viral load >400 copies/mL (aOR = 5.56, 95% CI 1.58–19.5, p = 0.007) and a non-European origin (aOR = 4.26, 95% CI 1.02–17.9, p = 0.047). HIV-infected patients with a higher burden of comorbidities, uncontrolled HIV replication, low CD4-cell counts and/or of non-European origin are at higher risk of developing IPD. Better screening for and management of HIV infection is necessary to reduce the risk of IPD.

Urinary tract infection in diabetes: epidemiologic considerations

The epidemiology of urnary tract infections (UTIs) among men and women with diabetes is similar to the epidemiology of those without: Women have greater risk than men, and frequency of sexual activity is a risk factor. The bacteriology and antibiotic susceptibility patterns also do not, in general, differ from those without diabetes. Although persons with diabetes are more likely to have asymptomatic bacteriuria, asymptomatic bacteriuria does not lead to increased risk of symptomatic infection, except during pregnancy or prior to genital-urinary or gastrointestinal surgery, and should not be treated otherwise. However, diabetes doubles the risk of UTI. The source of this increase is not well understood, although bladder dysfunction, which increases with duration of diabetes, and glycosuria are hypothesized mechanisms. As treatment using sodium glucose cotransporter 2 inhibitors-which lead to glycosuria-increases, there is a potential for the frequency of UTI to increase among those with diabetes.

High levels of atazanavir and darunavir in urine and crystalluria in asymptomatic patients

OBJECTIVES

Atazanavir has been associated with kidney stones and renal failure. We measured urine and plasma concentrations of recent protease inhibitors (PIs) and searched for PI crystals in the urine of asymptomatic patients.

METHODS

A cross-sectional analysis of HIV-infected patients taking ritonavir-boosted atazanavir 300 mg/day (ATV300/r), unboosted atazanavir 400 mg/day (ATV400), ritonavir-boosted darunavir at either 800 mg/day (DRV800/r) or 1200 mg/day (DRV1200/r) or ritonavir-boosted lopinavir 800 mg/day was performed. Plasma and urine were collected and PI levels measured using HPLC. Crystals were detected and identified in urine using polarized microscopy.

RESULTS

PI levels were measured in 266 patients, 142 of whom were assessed for urinary crystals. Their mean age was 46 years. The mean duration of HIV infection was 10.5 years and the mean duration of the current PI-containing regimen was 22.5 months. The mean CD4 cell count was 494 cells/mm(3); 74% showed controlled HIV replication. Median urinary PI levels were 22.3, 14.3, 26.9 and 29.7 mg/L for ATV300/r, ATV400, DRV800/r and DRV1200/r, respectively, significantly higher than plasma levels, which were all <5 mg/L (P < 0.001). In contrast, median urinary lopinavir concentrrations did not significantly differ from plasma concentrations (4.2 and 6.4 mg/L, respectively; P = 0.7) and were significantly lower than those of other PIs (P < 0.001). Atazanavir crystals were found in 7/78 patients receiving ATV300/r (8.9%; 95% CI = 2.6%-15.2%) and darunavir crystals were found in 4/51 patients receiving darunavir (7.8%; 95% CI = 0.4%-15.2%). Longer exposure to atazanavir was the only risk factor associated with the presence of atazanavir crystalluria (P = 0.04).

CONCLUSIONS

Unlike lopinavir, atazanavir and darunavir reached high concentrations in urine. Urinary crystals were found in a few patients receiving ritonavir-boosted atazanavir or darunavir and may favour nephrolithiasis.

Diversity of individual dynamic patterns of emergence of resistance to quinolones in Escherichia coli from the fecal flora of healthy volunteers exposed to ciprofloxacin

BACKGROUND

Emergence of quinolone-resistant Escherichia coli (QREC) is an increasing clinical challenge mostly originating in fecal microbiota. The dynamics of the emergence of QREC in feces from individuals exposed to ciprofloxacin is unknown.

METHODS

A total of 48 healthy volunteers received oral ciprofloxacin for 14 days. Fecal specimens were collected on days 0, 8, 14, and 42. Subpopulations of QREC were detected on selective agar, genetically characterized, and compared with quinolone-susceptible E. coli (QSEC) strains collected on different days.

RESULTS

On day 42, 34 subjects carried QSEC, and 14 carried QREC. Of the 14 who carried QREC, 9 carried quinolone-susceptible E. coli on day 0, 1 carried E. coli with a lower level of quinolone resistance on day 0, and 4 carried E. coli with similar levels of resistance and RAPD-genotypes on days 0 and 42. No plasmid acquisition and no selection of resistant mutants from the initial microbiota was evidenced in any case.

CONCLUSIONS

In QREC emerging under ciprofloxacin pressure in the fecal microbiota, no proof of selection of quinolone-resistant mutants from the initial microbiota was evidenced, suggesting that QREC strains on day 42 were either present at undetectable levels in the initial microbiota or that exogenous acquisition of QREC strains occurred. Clinical Trials Registration. NCT00190151.

AIDS-related Kaposi's sarcoma can occur during peginterferon-α and ribavirin therapy for chronic hepatitis C infection

INTRODUCTION

Before the arrival of highly active antiretroviral therapy (HAART), interferon α has been used successfully to treat AIDS-related Kaposi's sarcoma (KS). Peginterferon-α (pegIFN-α) may still be used successfully in refractory KS.

CASE

Peginterferon-α and ribavirin (RBV) were initiated to treat hepatitis C virus (HCV) infection in an HIV-infected patient with high CD4 counts having discontinued antiretroviral therapy (ART). He developed disseminated KS 6 months after HCV treatment began. Beginning of ART, discontinuation of pegIFN/RBV, and 2 cycles of doxorubicine were necessary to treat KS.

DISCUSSION

Despite its activity on KS, thanks to its antiviral and antiangiogenic properties, PegIFN was unable to prevent the occurrence of severe KS. The absence of ART, despite high CD4 counts, and interferon-induced lymphopenia probably triggered the occurrence of KS in this patient.

Optimization of bacterial diagnosis yield after needle aspiration in immunocompetent adults with brain abscesses

OBJECTIVE

Brain abscesses (BA) are life threatening, even in immunocompetent patients, in part because microbiological diagnosis is often lacking and management is empirical. Recent epidemiological changes make it all the more important to have a precise microbiological diagnosis. Our purpose was to evaluate the efficacy of a strategy aimed at obtaining a microbiological diagnosis in immunocompetent patients presenting with suspected BAs.

METHODS

We conducted a cohort study including all consecutive patients suspected of having BAs according to clinical, biological, and radiological findings. Severely immunocompromised patients were excluded. Aspiration was performed free-hand in patients with superficial abscesses (<1 cm depth from the cortical surface) and under stereotactic guidance in patients with deep-seated abscesses. Microbiological diagnosis was optimized, using the best aerobic and anaerobic growth conditions, blood culture bottles inoculated in the operating room, and molecular biology techniques if necessary. Antibiotic treatment was adapted according to the findings.

RESULTS

Twenty-six patients were suspected of having BAs during the study period. Twenty-four patients benefited from aspiration (stereotactic puncture in 3 cases), which was safe, confirmed the diagnosis of BAs, and yielded microbiological diagnosis in all cases, even in those patients who had previously received antibiotics (n = 8; 33%). In 10 patients (42%), microbiological results led to a different choice in antibiotic therapy than the recommended empirical regimen.

CONCLUSION

Microbiological diagnosis can be obtained in all cases of BA. This is achieved by the conjunction of rapid needle aspiration and the optimization of microbiological diagnosis resulting from fast management of the surgical specimen, good anaerobic culture conditions, and the use of blood culture bottles and molecular biology techniques when appropriate. Moreover, it is of clinical and therapeutic interest when BAs are suspected in immunocompetent patients.

Bone involvement in generalized crystal-storing histiocytosis

The abnormal secretion of monoclonal immunoglobulins observed with monoclonal gammopathies and other clonal B cell dyscrasias can be responsible for a spectrum of deposition disorders. Crystal-storing histiocytosis (CSH) is a rare disease affecting patients with B cell dyscrasias and monoclonal gammopathies, characterized by the accumulation of histiocytes that have phagocytosed an abnormal crystalline immunoglobulin. We describe 2 cases of this rare disorder with multiorgan involvement and prominent bone involvement. Magnetic resonance imaging showed bone marrow infiltration and images of avascular necrosis. Bone specimen analysis gave histological proof of diffuse bone infiltration by the abnormal histiocytes. Bone involvement, which appears to be a specific feature of CSH, links this entity to other storage disorders, such as Gaucher disease. Because the accumulation of abnormal immunoglobulin-loaded histiocytes is clearly pivotal, CSH should be considered not only as an immunoglobulin deposition disease but also as a storage histiocytic disorder.