Evolution of fluoroquinolone-resistant Escherichia coli in the gut after ciprofloxacin treatment.

BACKGROUND: Three healthy volunteers carried similar quinolone-resistant E. coli (QREC) (pulsed field gel electrophoresis profiles) in their gut before and after 14 days ciprofloxacin treatment. Given the intensity of the selective pressure and the mutagenic properties of quinolones, we determined whether these strains had evolved at the phenotypic and/or genomic levels. MATERIAL AND METHODS: Commensal QREC from before day-0 (D0), and a month after 14 days of ciprofloxacin (D42) were compared in 3 volunteers. Growth experiments were performed; acetate levels, mutation frequencies, quinolone MICs and antibiotic tolerance were measured at D0 and D42. Genomes were sequenced and single nucleotide polymorphisms (SNPs) between D0 and D42 were analyzed using DiscoSNP and breseq methods. Cytoplasmic proteins were extracted, HPLC performed and proteins identified using X!tandem software; abundances were measured by mass spectrometry using the Spectral Counting (SC) and eXtraction Ion Chromatograms (XIC) integration methods. RESULTS: No difference was found in MICs, growth characteristics, acetate concentrations, mutation frequencies, tolerance profiles, phylogroups, O-and H-types, fimH alleles and sequence types between D0 and D42. No SNP variation was evidenced between D0 and D42 isolates for 2/3 subjects; 2 SNP variations were evidenced in one. At the protein level, very few significant protein abundance differences were identified between D0 and D42. CONCLUSION: No fitness, tolerance, metabolic or genomic evolution of commensal QREC was observed overtime, despite massive exposure to ciprofloxacin in the gut. The three strains behaved as if they had been unaffected by ciprofloxacin, suggesting that gut may act as a sanctuary where bacteria would be protected from the effect of antibiotics and survive without any detrimental effect of stress.

Dimercaptosuccinic acid in combination with carbapenems against isogenic strains of Escherichia coli producing or not producing a metallo-ß-lactamase in vitro and in murine peritonitis.

BACKGROUND: Carbapenemase-producing Enterobacterales represent a major therapeutic challenge. MBLs, requiring zinc at their catalytic site, could be inhibited by meso-dimercaptosuccinic acid (DMSA), a heavy metal chelator already widely used for treating lead intoxication. OBJECTIVES: To evaluate the activity of carbapenems alone or combined with DMSA against MBL-producing Escherichia coli in a severe murine peritonitis model. METHODS: Isogenic strains of wild-type E. coli CFT073 producing the MBLs NDM-1, VIM-2 and IMP-1, and the control serine carbapenemases OXA-48 and KPC-3 were constructed. MIC determinations and time-kill assays were performed for imipenem, meropenem and ertapenem alone or in combination with DMSA. Infected mice were treated intraperitoneally for 24 h with imipenem, DMSA or their combination. Bacterial counts in peritoneal fluid and spleen were assessed at 24 h. RESULTS: DMSA in combination with each carbapenem caused a significant decrease in the MICs for all MBL-producing strains, in a concentration-dependent manner, but did not provide benefit against non-MBL strains. In mice infected with the NDM-1-producing strain, the combination of imipenem and DMSA significantly reduced bacterial counts in peritoneal fluid (P = 0.0006) and spleen (P < 0.0001), as compared with imipenem alone, with no benefit against the KPC-3-producing and CFT073 strains. DMSA concentrations in plasma of mice were comparable to those obtained in humans with a standard oral dose. CONCLUSIONS: DMSA restores the activity of carbapenems against MBL-producing strains, and its combination with carbapenems appears to be a promising strategy for the treatment of NDM-producing E. coli infections.

Mortality in Escherichia coli bloodstream infections: antibiotic resistance still does not make it.

BACKGROUND: Escherichia coli bloodstream infections (BSIs) account for high mortality rates (5%-30%). Determinants of death are unclear, especially since the emergence of ESBL producers. OBJECTIVES: To determine the relative weight of host characteristics, bacterial virulence and antibiotic resistance in the outcome of patients suffering from E. coli BSI. METHODS: All consecutive patients suffering from E. coli BSI in seven teaching hospitals around Paris were prospectively included for 10 months. E. coli isolates were sequenced using Illumina NextSeq technology to determine the phylogroup, ST/ST complex (STc), virulence and antimicrobial resistance gene content. Risk factors associated with death at discharge or Day 28 were determined. RESULTS: Overall, 545 patients (mean ± SD age 68.5 ±âŸ16.5 years; 52.5% male) were included. Mean Charlson comorbidity index (CCI) was 5.6 (± 3.1); 19.6% and 12.8% presented with sepsis and septic shock, respectively. Portals of entry were mainly urinary (51.9%), digestive (41.9%) and pulmonary (3.5%); 98/545 isolates (18%) were third-generation cephalosporin resistant (3GC-R), including 86 ESBL producers. In-hospital death (or at Day 28) was 52/545 (9.5%). Factors independently associated with death were a pulmonary portal of entry [adjusted OR (aOR) 6.54, 95% CI 2.23-19.2, P = 0.0006], the iha_17 virulence gene (aOR 4.41, 95% CI 1.23-15.74, P = 0.022), the STc88 (aOR 3.62, 95% CI 1.30-10.09, P = 0.014), healthcare-associated infections (aOR 1.98, 95% CI 1.04-3.76, P = 0.036) and high CCI (aOR 1.14, 95% CI 1.04-1.26, P = 0.006), but not ESBL/3GC-R. CONCLUSIONS: Host factors, portal of entry and bacterial characteristics remain major determinants associated with mortality in E. coli BSIs. Despite a high prevalence of ESBL producers, antibiotic resistance did not impact mortality. (ClinicalTrials.gov identifier: NCT02890901.).

Activity of fosfomycin alone or combined with temocillin in vitro and in a murine model of peritonitis due to KPC-3- or OXA-48-producing Escherichia coli.

Background: Alternative therapeutic regimens are urgently needed against carbapenemase-producing Enterobacteriaceae. Fosfomycin often remains active against KPC and OXA-48 producers, but emergence of resistance is a major limitation. Our aim was to determine whether the association of temocillin with fosfomycin might be useful to treat KPC- or OXA-48-producing Escherichia coli infections. Methods: Isogenic derivatives of E. coli CFT073 with blaKPC-3- or blaOXA-48-harbouring plasmids (named CFT073-KPC-3 and CFT073-OXA-48, respectively) were used. The addition of temocillin to fosfomycin was tested using the chequerboard method and time-kill curves as well as in a fatal peritonitis murine model. Mice were treated for 24 h with fosfomycin alone or in combination with temocillin. Bacterial loads, before and after treatment, were determined in the peritoneal fluid and fosfomycin-resistant mutants were detected. Results: Temocillin MICs were 8, 32 and 256 mg/L for CFT073 (WT), CFT073-KPC-3 and CFT073-OXA-48, respectively. Fosfomycin MIC was 0.5 mg/L for all strains. The chequerboard experiments demonstrated synergy for all three strains. In time-kill curves, combining temocillin with fosfomycin was synergistic, bactericidal and prevented emergence of resistance for CFT073-pTOPO and CFT073-KPC-3, but not CFT073-OXA-48. In vivo, for the three strains, bacterial counts were lower in peritoneal fluid with the combination compared with fosfomycin alone (P < 0.001) and inhibited growth of resistant mutants in all cases. Conclusions: The combination of fosfomycin and temocillin demonstrated a benefit in vitro and in vivo against E. coli strains producing KPC-3 or OXA-48-type carbapenemases. This combination prevented the emergence of fosfomycin resistance and proved to be more bactericidal than fosfomycin alone.

Biological cost of fosfomycin resistance in Escherichia coli in a murine model of urinary tract infection.

Prevalence of fosfomycin resistance in E. coli clinical isolates from UTIs remains very low. Our hypothesis was that fosfomycin resistance may be associated with a biological cost. Three groups of strains of E. coli belonging to the B2 phylogenetic group were used: clinical wild-type (WT) isolates, clinical multidrug-resistant isolates and in vitro fosfomycin-resistant derivatives from the uropathogen clinical strain E. coli CFT073. In each group fosfomycin-susceptible and -resistant isolates were compared. In vitro, we found a significantly decreased growth rate for fosfomycin-resistant strains as compared with susceptible strains in the WT group. In a murine model of ascending UTI, there was a significant reduction in infection rates with fosfomycin-resistant isolates as compared with susceptible ones, in all 3 study groups, ranging from 28 to 39% (P<0.03). All fosfomycin-susceptible clinical strains were virulent in vivo (13/13), while fosfomycin-resistant clinical strains were either virulent (2/7) or non-virulent (5/7) (P<0.002). This difference was not explained by the number of virulence factors or pathogenicity-associated islands. In conclusion, fosfomycin resistance appears to carry some biological cost in E. coli, which may explain in part the apparent paradox of the low prevalence of fosfomycin resistance despite a high rate of spontaneous mutants.

Cefotaxime and Amoxicillin-Clavulanate Synergism against Extended-Spectrum-ß-Lactamase-Producing Escherichia coli in a Murine Model of Urinary Tract Infection.

We investigated the efficacies of cefotaxime (CTX) and amoxicillin (AMX)-clavulanate (CLA) (AMC) against extended-spectrum-ß-lactamase (ESBL)-producing Escherichia coli in vitro and in a murine model of urinary tract infection (UTI). MICs, the checkerboard dilution method, and time-kill curves were used to explore the in vitro synergism between cefotaxime and amoxicillin-clavulanate against two isogenic E. coli strains-CFT073-RR and its transconjugant, CFT073-RR Tc bla(CTX-M-15)-harboring a bla(CTX-M-15) plasmid and a bla(OXA-1) plasmid. For in vivo experiments, mice were separately infected with each strain and treated with cefotaxime, amoxicillin, and clavulanate, alone or in combination, or imipenem, using therapeutic regimens reproducing time of free-drug concentrations above the MIC (fT≥MIC) values close to that obtained in humans. MICs of amoxicillin, cefotaxime, and imipenem were 4/>1,024, 0.125/1,024, and 0.5/0.5 mg/liter, for CFT073-RR and CFT073-RR Tc bla(CTX-M-15), respectively. The addition of 2 mg/liter of clavulanate (CLA) restored the susceptibility of CFT073-RR Tc bla(CTX-M-15) to CTX (MICs of the CTX-CLA combination, 0.125 mg/liter). The checkerboard dilution method and time-kill curves confirmed an in vitro synergy between amoxicillin-clavulanate and cefotaxime against CFT073-RR Tc bla(CTX-M-15). In vivo, this antibiotic combination was similarly active against both strains and as effective as imipenem. In conclusion, the cefotaxime and amoxicillin-clavulanate combination appear to be an effective, easy, and already available alternative to carbapenems for the treatment of UTI due to CTX-M-producing E. coli strains.

Activity of temocillin in a lethal murine model of infection of intra-abdominal origin due to KPC-producing Escherichia coli.

OBJECTIVES: Temocillin is a 6-α-methoxy derivative of ticarcillin that shows in vitro activity against Enterobacteriaceae producing Klebsiella pneumoniae carbapenemase (KPC). Our objective was to assess in vivo temocillin activity against KPC-producing Escherichia coli. METHODS: Isogenic derivatives of the WT E. coli CFT073 producing KPC-2, KPC-3 or OXA-48 were constructed. An experimental murine model of intra-abdominal infection with sepsis was used. Mice were treated subcutaneously with temocillin 200 mg/kg every 2 h for 24 h, reproducing the duration of time that the free serum concentration of temocillin exceeded the MIC in humans with a regimen of 2 g every 12 h or 2 g every 8 h. Blood, peritoneal fluid (PF) and spleen were collected; 24 h survival and sterility rates were assessed. RESULTS: Temocillin MICs were 8, 16, 32, and 256 mg/L for the susceptible strain and KPC-2-, KPC-3-, and OXA-48-producing strains, respectively. In mice treated with temocillin, significant bacterial reduction was obtained in PF, blood, and spleen for the susceptible strain and KPC-2- and KPC-3-producing strains (P < 0.001) but not for the OXA-48-producing strain. Sterility rates in PF were 53%, 10%, 0% and 0% (P < 0.001) and sterility rates in blood were 77%, 40%, 3% and 0% (P < 0.001), while survival rates were 97%, 97%, 57%, 0% (P < 0.001) for mice infected with the susceptible strain and KPC-2-, KPC-3- and OXA-48-producing strains, respectively. CONCLUSIONS: In a lethal-infection model with bacteraemia from intra-abdominal origin, temocillin retained significant activity in PF, blood and spleen and prevented death in mice by effectively working against KPC-producing E. coli with temocillin MICs ≤16 mg/L.

Activity of temocillin in a murine model of urinary tract infection due to Escherichia coli producing or not producing the ESBL CTX-M-15.

OBJECTIVES: Temocillin is a 6α-methoxy derivative of ticarcillin that is resilient to ESBLs. Prospective data about its in vivo activity remain scarce. Our aims were: (i) to evaluate the activity of temocillin in a urinary tract infection (UTI) model due to ESBL-producing Escherichia coli and compare it with that of imipenem; and (ii) to define in vivo susceptibility breakpoints. METHODS: Mice were infected with a susceptible E. coli CFT073-RR or its transconjugant (CFT073-RR Tc) harbouring a blaCTX-M-15-carrying plasmid, using an ascending UTI model. Therapeutic regimens were chosen in order to reproduce percentage of time of free drug concentrations above MIC (fT>MIC) obtained in humans with standard regimens of temocillin (200 mg/kg every 2 h for 2 g every 12 h) or imipenem (100 mg/kg every 2 h for 1 g every 8 h). Additional regimens of temocillin (200 mg/kg every 4 and 6 h) with reduced fT>MIC were studied. RESULTS: MICs of temocillin and imipenem were 4/8 and 0.5/0.5 mg/L, for CFT073-RR and CFT073-RR Tc, respectively. In vivo, when given every 2 h (fT>MIC = 82% and 70%), temocillin was bactericidal and as effective as imipenem in kidneys against both strains without selecting resistant mutants. Temocillin remained active even when given every 4 h, generating an fT>MIC of 41% and 35%, which corresponded to a breakpoint of 16 mg/L in humans with the standard regimen. CONCLUSIONS: Our observations support the consideration of a standard regimen of temocillin as an alternative to carbapenems for the treatment of UTI due to CTX-M-producing E. coli strains with an MIC of 16 mg/L or less.

Quinolone-resistant Escherichia coli from the faecal microbiota of healthy volunteers after ciprofloxacin exposure are highly adapted to a commensal lifestyle.

OBJECTIVES: Quinolone-resistant Escherichia coli (QREC) primarily emerge in commensal bacteria under selective pressure. The aim of this work was to investigate the characteristics of QREC from the faecal microbiota after quinolone exposure, as they remain largely unknown. METHODS: Forty-eight healthy volunteers received ciprofloxacin from day 1 to day 14. QREC were detected in stools from 14 subjects at day 42. QREC were compared in terms of genetic background, metabolic properties, stress resistance and intestinal colonization abilities with quinolone-susceptible E. coli (QSEC) from the same 14 individuals and from 29 volunteers who remained QREC-free. RESULTS: QREC always belonged to a single clone for a given volunteer and to restricted phylogenetic groups. QREC carried significantly more iron capture systems than QSEC. Maximum growth rates in minimal medium with gluconate, general stress regulator RpoS activity assessed by iodine staining and resistance to oxidative and acid stresses were significantly higher for QREC than for QSEC. In a mouse colonization model, QREC efficiently colonized the intestine microbiota despite the presence of QSEC competitors. At day 42, QREC and QSEC faecal counts from the 14 volunteers were comparable except in three subjects where only QREC could be detected. CONCLUSIONS: These results suggest that QREC do not have a fitness cost, probably as a result of genetic co-selection, but are highly adapted to a commensal lifestyle. They may not be eliminated easily from the faecal microbiota from healthy subjects once selected.

Escherichia coli bacteraemia in adults: age-related differences in clinical and bacteriological characteristics, and outcome.

To explore the specificities of Escherichia coli bacteraemia in the elderly, the demographic, clinical and bacteriological characteristics and in-hospital mortality rate of 'young' (18-64 years, n = 395), 'old' (65-79 years, n = 372) and 'very old' (⩾80 years, n = 284) adult patients of the multicentre COLIBAFI cohort study were compared. Clinical and bacteriological risk factors for death were jointly identified by logistic regression and multivariate analysis within each group. 'Young' and 'old' patients had more comorbidities than 'very old' patients (comorbidity score: 1·5 ± 1·3 and 1·6 ± 1·2 vs. 1·2 ± 1·2, respectively; P < 0·001), and were more frequently nosocomially infected (22·3% and 23·8% vs. 8·8%, respectively; P < 0·001). 'Old' patients had the poorest prognosis (death rate: 16·4% vs.10·4% for 'young' and 12·0% for 'very old' patients, respectively; P = 0·039). Risk factors for death were age group-specific, suggesting a host-pathogen relationship evolving with age.

Ciprofloxacin treatment failure in a murine model of pyelonephritis due to an AAC(6')-Ib-cr-producing Escherichia coli strain susceptible to ciprofloxacin in vitro.

AAC(6')-Ib-cr is a plasmid-mediated quinolone resistance mechanism described worldwide for Escherichia coli. Since it confers in vitro only a low level of resistance to ciprofloxacin, we evaluated its impact on the in vivo activity of ciprofloxacin. Isogenic strains were obtained by transferring plasmid p449, harboring aac(6')-Ib-cr, into the quinolone-susceptible strain E. coli CFT073-RR and its D87G gyrA mutant. MICs were 0.015, 0.06, 0.25, and 0.5 µg/ml against E. coli strains CFT073-RR, CFT073-RR/p449, CFT073-RR GyrA(r), and CFT073-RR GyrA(r)/p449, respectively. Bactericidal activity was reduced at 1× the MIC for the three resistant derivatives, while at a fixed concentration of 0.5 µg/ml, 99.9% killing was observed for all strains except E. coli CFT073-RR GyrA(r)/p449. In the murine model of pyelonephritis, an optimal regimen of ciprofloxacin (10 mg/kg of body weight twice a day [b.i.d.]) significantly decreased the bacterial count in the kidneys of mice infected with E. coli CFT073 (1.6 versus 4.3 log10 CFU/g of kidney compared to untreated controls; P = 0.0001), while no significant decrease was observed for E. coli CFT073-RR/p449 (2.7 versus 3.1 log10 CFU/g; P = 0.84), E. coli CFT073-RR GyrA(r) (4.2 versus 4.1 log10 CFU/g; P = 0.35), or E. coli CFT073-RR GyrA(r)/p449 (2.9 versus 3.6 log10 CFU/g; P = 0.47). While pharmacokinetic and pharmacodynamic (PK/PD) parameters accounted for ciprofloxacin failure against gyrA-containing mutants, this was not the case for the aac(6')-Ib-cr-containing strains, suggesting an in situ hydrolysis of ciprofloxacin in the latter case.

Pharmacokinetic interaction between rifampicin and clindamycin in staphylococcal osteoarticular infections.

OBJECTIVES: Oral combination of clindamycin and rifampicin is relevant for the treatment of staphylococcal osteoarticular infection (SOAIs). However, rifampicin induces CYP3A4, suggesting a pharmacokinetic interaction with clindamycin with unknown pharmacokinetic/pharmacodynamic (PK/PD) consequences. This study aimed to quantify clindamycin PK/PD markers before and during rifampicin co-administration in SOAI. METHODS: Patients with SOAI were included. After initial intravenous antistaphylococcal treatment, oral therapy was started with clindamycin (600 or 750 mg t.i.d.), followed by addition of rifampicin 36 h later. Population PK analysis was performed using the SAEM algorithm. PK/PD markers were compared with and without rifampicin co-administration, each patient being his own control. RESULTS: In 19 patients, clindamycin median (range) trough concentrations were 2.7 (0.3-8.9) mg/L and <0.05 (<0.05-0.3) mg/L before and during rifampicin administration, respectively. Rifampicin co-administration increased clindamycin clearance by a factor 16 and reduced the AUC0-8h/MIC by a factor 15 (P < 0.005). Clindamycin plasma concentrations were simulated for 1000 individuals, without and with rifampicin. Against a susceptible Staphylococcus aureus strain (clindamycin MIC 0.0625 mg/L), >80% of individuals would reach all proposed PK/PD targets without co-administration of rifampicin, even with low clindamycin dose. For the same strain, when rifampicin was co-administered, the probability to reach clindamycin PK/PD targets dropped to 1% for %fT>MIC = 100% and to 6% for AUC0-24h/MIC > 60, even with high clindamycin dose. CONCLUSION: Rifampicin co-administration with clindamycin has a high impact on clindamycin exposure and PK/PD targets in SOAI, which could result in clinical failure even for fully susceptible strains.

Clinical predictive values of extended-spectrum beta-lactamase carriage in patients admitted to medical wards.

We aimed to reassess, through clinical items, populations at risk for extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) carriage at admission to hospital and to assess the risk of further positive clinical culture of ESBL-E among carriers. We performed a 5-month cohort study in a medicine ward of a 500-bed university teaching hospital in the Parisian area of France. All admitted patients were prospectively enrolled for rectal swabbing and clinical data collection, including bacterial infection at admission and during stay. Variables associated with ESBL-E carriage were identified by univariate and multivariate analysis. Five hundred patients were included. The prevalence of ESBL-E was 6.6% (33/500) upon admission. Only previous carriage of multidrug-resistant bacteria (MDRB) was associated with carriage (odds ratio [OR]: 17.7, 95% confidence interval (CI) 5.8-54.2, p < 0.001), yet, the positive predictive value (PPV) was not higher than 50%. When prior MDRB carriage was not considered in the multivariate analysis, only prior antibiotic consumption was found to be associated with carriage at admission (OR: 2.2 [1.1-4.5], p = 0.02). Two patients had ESBL-E infection at admission, yet, no patient became infected with ESBL-E during their stay. The clinical prediction of ESBL carriage at admission in our wards was found to be poorly efficient for assessing the at-risk population.

[Characteristics of patients admitted from emergency units in 18 internal medicine departments and organisation of these departments: A cross sectional study from SNFMI (SiFMI study group) in 2015]. / Caractéristiques des patients admis en médecine interne dans 18 hôpitaux français en aval des urgences et organisation de ces services : enquête transversale de la SNFMI (groupe d'étude SiFMI) en 2015.

INTRODUCTION: Patients admitted from emergency units represent a large portion of the population in internal medicine departments. The aim of this study is to identify characteristics of patients and organization of these departments. METHODS: Between June 29th and July 26th 2015, voluntary internal medicine departments from the SiFMI group prospectively filled anonymized internet forms to collect data of each patients admitted in their ward from emergency units, during seven consecutive days. RESULTS: Three hundred and sixty-five patients from emergency departments were admitted in 18 internal medicine inpatients departments, totalling 1100 beds and 33,530 annual stays, 56% of them for emergency units inpatients. Mean age was 68 years, 54% were women, mean Charlson score was 2.6 and 44% of the patients took at least three drugs. Main causes of hospitalization were infectious (29%) and neurological (17%) diseases. Mean length of stay was 9.2 days. The medical team was composed by a median value of 4,5 [2,75-6,25] senior full-time equivalents, 86% were internists. Each department except one received residents, two third of them were from general medicine. CONCLUSION: This study highlights a high organizational variability among internal medicine departments and patients, and sets internal medicine as a specialty with a great capacity to achieve an integrative/comprehensive management of patients and to offer a comprehensive basis for physicians in training.

Expression of CTX-M-15 limits the efficacy of ceftolozane/tazobactam against Escherichia coli in a high-inoculum murine peritonitis model.

OBJECTIVES: Among carbapenem-sparing therapies, ceftolozane/tazobactam has been proposed for the treatment of infections due to CTX-M-15-producing Escherichia coli. However, few data exist on its in vivo activity in infections associated with a high bacterial inoculum. METHODS: We analysed ceftolozane/tazobactam activity against susceptible E. coli CFT073-RR and its CTX-M-15-producing transconjugant E. coli CFT073-RR Tc blaCTX-M-15, in vitro at low and high inocula, and in a high-inoculum murine model of peritonitis. RESULTS: Against E. coli CFT073-RR Tc blaCTX-M-15, ceftolozane/tazobactam bactericidal effect was impaired in vitro with only a minor inoculum effect; this translated into reduced activity compared with imipenem in the mouse peritonitis model. CONCLUSIONS: Combination of extended spectrum ß-lactamase expression and high inoculum size may be a clinical situation at risk of reduced bactericidal activity of ceftolozane/tazobactam.

[Association between psychiatric comorbidities and hospital length of stay in post-emergency internal medicine patients]. / Association des comorbidités psychiatriques avec la durée de séjour des patients en médecine interne d'aval des urgences.

INTRODUCTION: Patients with psychiatric disorders suffer from a higher rate of somatic disorders than those without psychiatric disorder, often inappropriately managed. Our study aimed to describe patients with psychiatric comorbidity in post-emergency internal medicine units and to compare their length of hospital stay to patients without psychiatric disease. METHODS: This French cross sectional study used the data warehouse of the greater Paris hospitals. It included, all patients hospitalized through the emergency department in 9 internal medicine departments during the year 2017. Psychiatric disorders and the burden of somatic disorders (Charlson score) were determined through diagnostic coding. Charlson score and hospital length of stay were compared between patients with and without psychiatric comorbidity. RESULTS: In total, 8981 hospital stays (8001 patients) were included, 1867 (21%) with psychiatric comorbidity. After adjusting for age, gender, hospital and main diagnosis, the Charlson score was on average 0.68 higher in the psychiatric comorbidity group (P<0.001) and the length of hospital stay was 30% higher after further adjustment on the Charlson score (P<0.001). These differences were consistent for each main diagnosis. CONCLUSION: Patients with psychiatric comorbidity are frequent in post-emergency internal medicine wards. They experience longer hospital stays, only partly related with a higher burden of somatic disorders. Special attention should be paid to this vulnerable population.

[Insights on the management of Lyme disease]. / Actualités sur la prise en charge de la maladie de Lyme.

Lyme disease is currently a hot topic in France due to a high incidence in some areas. Its clinical polymorphism can lead to misdiagnosis on one hand and to unjustified treatment on the other hand. Clinical symptoms vary considerably according to involved organs (skin, central and/or peripheral nervous system, joints, heart, eyes) and may be limited to or associated with general non-specific signs. Biological exams must be guided by clinical symptoms to help diagnosis and treatment decision according to clinical history, presentation, time of onset and duration of symptoms. However, to date, no serologic test can discriminate between past and active disease. The role of the internist is two-fold: make a diagnosis when faced with general or focal symptoms and avoid inappropriate attribution to Lyme disease of symptoms related to alternate diagnoses.

Acute cholangitis: Diagnosis and management.

Acute cholangitis is an infection of the bile and biliary tract which in most cases is the consequence of biliary tract obstruction. The two main causes are choledocholithiasis and neoplasia. Clinical diagnosis relies on Charcot's triad (pain, fever, jaundice) but the insufficient sensitivity of the latter led to the introduction in 2007 of a new score validated by the Tokyo Guidelines, which includes biological and radiological data. In case of clinical suspicion, abdominal ultrasound quickly explores the biliary tract, but its diagnostic capacities are poor, especially in case of non-gallstone obstruction, as opposed to magnetic resonance cholangiopancreatography and endoscopic ultrasound, of which the diagnostic capacities are excellent. CT scan is more widely available, with intermediate diagnostic capacities. Bacteriological sampling through blood cultures (positive in 40% of cases) and bile cultures is essential. A wide variety of bacteria are involved, but the main pathogens having been found are Escherichia coli and Klebsiella spp., justifying first-line antimicrobial therapy by a third-generation cephalosporin. Systematic coverage of Enterococcus spp. and anaerobic infections remains debated, and is usually recommended, in case of severity criteria for Enterococcus severity levels, or anaerobic bilio-digestive anastomosis for anaerobes. Presence of a biliary stent is the only identified risk-factor associated with infections by multidrug-resistant pathogens. Along with antimicrobial therapy, endoscopic or radiological biliary drainage is a crucial management component. Despite improved management, mortality in cases of acute cholangitis remains approximately 5%.

The inoculum effect of Escherichia coli expressing mcr-1 or not on colistin activity in a murine model of peritonitis.

OBJECTIVES: Colistin often remains the last resort antibiotic active against carbapenemase-producing Enterobacteriaceae. However, while in vitro inoculum effect has been reported, therapeutic relevance of this phenomenon remains questioned. METHODS: Ten E. coli strains were used that included the wild-type CFT073 and its transconjugant CFT073-MCR-1 and eight susceptible clinical isolates. Mice with peritonitis were treated for 24 h with colistin sulfate. Bacterial loads were determined in peritoneal fluid (PF) and spleen and colistin-resistant mutants were detected. RESULTS: MICs of colistin against the eight susceptible clinical strains and CFT073 ranged from 0.125 to 0.5 mg/L with an inoculum of 105 CFU/mL and from 2 to 4 mg/L with a 107 CFU/mL inoculum; 5/9 strains with an MIC of 4 mg/L were considered resistant according to EUCAST breakpoint (resistance, > 2 mg/L). When the bacterial load of wild-type CFT073 inoculated in mice increased from 107 to 108 CFU: i) mean log10 CFU reduction generated by colistin in PF and spleen decreased from 5.8/mL and 3.1/g, respectively, (p < 0.01) to 0.9/mL and 0.8/g, respectively (NS); ii) mice survival rate decreased from 15/15 (100%) to 6/15 (40%) (p = 0.017); and iii) proportion of mice with selection of colistin-resistant mutants increased from 4/15 to 15/15 (p < 0.01). These results were comparable to those obtained when peritonitis was produced with a 107 CFU bacterial load of E. coli CFT073 expressing mcr-1, for which the mean log10 CFU reductions were 3.5/mL and 0.6/g in PF and spleen, respectively (NS), and survival rate was 8/15 (53%) (p < 0.01 versus survival of mice infected with wild-type CFT073). CONCLUSIONS: Phenotypic colistin resistance in wild-type E. coli due to an increase in inoculum size had a therapeutic impact in mice with peritonitis that was comparable to that observed when the mcr-1 gene was expressed.