Analysis of 15 cases from a monocentric cohort of 307 liver abscesses.

BACKGROUND: Out of the context of haematological patients, Candida sp. is rarely retrieved from pyogenic liver abscesses (PLA). OBJECTIVES: Our objective was to assess the risk factors for occurrence, and clinical, microbiological characteristics, management and outcome of Candida pyogenic liver abscesses (C-PLA). PATIENTS/METHODS: We retrospectively analysed C-PLA cases and compared them to pyogenic liver abscesses exclusively due to bacteria (B-PLA) included in our monocentric database on liver abscesses. Unfavourable course was defined as the occurrence of a primary treatment failure (PTF), recurrence after an initial cure, or death within 3 months after diagnosis. RESULTS: Between 2010 and 2018, 15 C-PLA and 292 B-PLA were included. All C-PLA had a biliary origin and were polymicrobial. All patients with C-PLA had at least one comorbidity at risk for Candida infection and 7 (53.3%) presented with sepsis requiring an admission in intensive care unit. Median duration of antifungal treatment was 42 days [24-55]. In multivariate analysis, compared with B-PLA, a medical history of malignancy (OR 4.16; 95%CI 1.15-18.72) or liver abscess (OR 7.39; 95%CI 2.10-26.62), and sepsis with severity criteria (OR 3.52; 95%CI 1.07-11.90) were independently associated with the occurrence of C-PLA. In multivariate analysis, C-PLA was associated with a higher risk of recurrence (HR 3.08; 95%CI 1.38-11.22). CONCLUSION: Candida liver abscesses in non-neutropenic is a rare and severe disease. The high rate of recurrence should lead to discuss a more intensive treatment.

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.

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.

The ST131 Escherichia coli H22 subclone from human intestinal microbiota: Comparison of genomic and phenotypic traits with those of the globally successful H30 subclone.

BACKGROUND: In 2006, we found healthy subjects carrying ST131 Escherichia coli in their intestinal microbiota consisting of two populations: a subdominant population of fluoroquinolone-resistant E. coli belonging to subclone H30 (H30-R or subclade C1), the current worldwide dominant ST131 subclone, and a dominant E. coli population composed of antibiotic-susceptible E. coli belonging to subclone H22 (clade B), the precursor of subclone H30. We sequenced the whole genome of fecal H22 strain S250, compared it to the genomes of ExPEC ST131 H30-Rx strain JJ1886 and commensal ST131 H41 strain SE15, sought the H22-H30 genomic differences in our fecal strains and assessed their phenotypic consequences. RESULTS: We detected 173 genes found in the Virulence Factor Database, of which 148 were shared by the three ST131 genomes, whereas some were genome-specific, notably those allowing determination of virotype (D for S250 and C for JJ1886). We found three sequences of the FimH site involved in adhesion: two in S250 and SE15 close and identical, respectively, to that previously reported to confer strong intestinal adhesion, and one in JJ1886, corresponding to that commonly present in uropathogenic E. coli. Among the genes involved in sugar metabolism, one encoding a gluconate kinase lacked in S250 and JJ1886. Although this gene was also absent in both our fecal H22 and H30-R strains, H22 strains showed a higher capacity to grow in minimal medium with gluconate. Among the genes involved in gluconate metabolism, only the ghrB gene differed between S250/H22 and JJ1886/H30-R strains, resulting in different gluconate reductases. Of the genes involved in biofilm formation, two were absent in the three genomes and one, fimB, in the JJ1886 genome. Our fecal H30-R strains lacking intact fimB displayed delayed biofilm formation relative to our fecal H22 strains. The H22 strains differed by subclade B type and plasmid content, whereas the H30-R strains were identical. CONCLUSIONS: Phenotypic analysis of our fecal strains based on observed genomic differences between S250 and JJ1886 strains suggests the presence of traits related to bacterial commensalism in our H22 strains and traits commonly found in uropathogenic E. coli in our H30-R strains.

In vitro activity of gentamicin, vancomycin or amikacin combined with EDTA or l-arginine as lock therapy against a wide spectrum of biofilm-forming clinical strains isolated from catheter-related infections.

OBJECTIVES: Treatment of catheter-related bloodstream infections (CRBSI) is hampered by the characteristic tolerance of bacterial biofilms towards antibiotics. Our objective was to study the effect of the combination of antibiotics and the alkaline amino acid l-arginine or the cation chelator EDTA on the bacterial killing of in vitro biofilms formed by an array of clinical strains responsible for CRBSI and representative of epidemiologically relevant bacterial species. METHODS: Among 32 strains described in a previous clinical study, we focused on the most antibiotic-tolerant strains including CoNS (n = 4), Staphylococcus aureus (n = 4), Enterococcus faecalis (n = 2), Pseudomonas aeruginosa (n = 4) and Enterobacteriaceae (n = 4). We used an in vitro biofilm model (96-well plate assay) to study biofilm tolerance and tested various combinations of antibiotics and non-antibiotic adjuvants. Gentamicin, amikacin or vancomycin was combined with disodium EDTA or l-arginine for 24 h to reproduce the antibiotic lock therapy (ALT) approach. Killing of biofilm bacteria was measured by cfu quantification after a vigorous step of pipetting up and down in order to detach all biofilm bacteria from the surface of the wells. RESULTS: Both of our adjuvant strategies significantly increased the effect of antibiotics against biofilms formed by Gram-positive and Gram-negative bacterial pathogens. The combination of gentamicin + EDTA was active against all tested strains apart from one P. aeruginosa. The combination of gentamicin + l-arginine was active against most of the tested strains with the notable exception of CoNS for which no potentiation was observed. We also demonstrated that amikacin + EDTA was active against Gram-negative bacteria and that vancomycin + EDTA was active against Gram-positive bacteria. CONCLUSIONS: The addition of EDTA enhanced the activity of gentamicin, amikacin and vancomycin against biofilms formed by a wide spectrum of bacterial strains responsible for CRBSI.

Differential contribution of AcrAB and OqxAB efflux pumps to multidrug resistance and virulence in Klebsiella pneumoniae.

OBJECTIVES: In Klebsiella pneumoniae, overexpression of the AcrAB efflux pump and the more recently described OqxAB efflux pump has been linked to an antibiotic cross-resistance phenotype, but the mechanisms of regulation are largely unknown. Moreover, while AcrAB has been shown to participate in K. pneumoniae virulence, the contribution of OqxAB has not yet been assessed. METHODS: In the present study we investigated a K. pneumoniae clinical isolate (KPBj1 E+), displaying cross-resistance to quinolones, chloramphenicol and cefoxitin, and its phenotypic revertant (KPBj1 Rev, susceptible to antibiotics) by using whole-genome sequencing, RT-PCR, complementation and a Caenorhabditis elegans virulence model. RESULTS: We detected a point mutation in the oqxR repressor gene of KPBj1 E+, which overexpressed genes rarA, encoding a transcriptional regulator, and oqxB, but not acrB. Complementation with wild-type oqxR restored antibiotic susceptibility and normalized rarA and oqxB expression levels. Whole-genome sequencing showed that KPBj1 Rev had lost the entire rarA-oqxABR locus, situated close to an integration hot spot of phage P4. This large deletion seemed responsible for the significantly lower virulence potential of strain KPBj1 Rev compared with KPBj1 E+. Moreover, we found that KPBj1 E+ ΔacrB was significantly less virulent than its parental strain. CONCLUSIONS: This work demonstrates the role of the overexpression of efflux pump OqxAB, due to a mutation in gene oqxR, in the antibiotic resistance phenotype of a clinical isolate, and suggests that the presence of AcrAB, associated with overexpression of OqxAB, is required for high virulence potential.

Prevalence of day-care centre children (France) with faecal CTX-M-producing Escherichia coli comprising O25b:H4 and O16:H5 ST131 strains.

OBJECTIVES: Determining the prevalence of children in day-care centres (DCCs) carrying faecal extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae and molecularly characterizing those belonging to the Escherichia coli species. METHODS: Stools were collected from children's diapers (January-April 2012) in randomly chosen DCCs and plated onto ChromID ESBL. Colonies growing on this medium were identified by the Vitek 2 system and tested for antibiotic susceptibility and for ESBL production by the double-disc synergy test. ESBL genotypes were determined as well as phylogenetic groups, ERIC-2 (enterobacterial repetitive intergenic consensus) PCR profiles and sequence types (STs) for the E. coli isolates. Serotypes, virotypes, fimH alleles, ESBL-carrying plasmids and PFGE patterns were determined for the ST131 E. coli isolates. RESULTS: Among 419 children from 25 participating DCCs, 1 was colonized by CTX-M-15-producing Klebsiella pneumoniae and 27 (6.4%) by E. coli, which all produced CTX-M enzymes [CTX-M-15 (37%), CTX-M-1 (26%), CTX-M-14 (22%), CTX-M-27 (11%) and CTX-M-22 (4%)]. The 27 E. coli isolates, 55.5% belonging to group B2, displayed 20 ERIC-2 PCR profiles and 16 STs. The ST131 E. coli isolates were dominant (44%), displayed serotypes O25b:H4 and O16:H5, fimH alleles 30 and 41 and virotypes A and C. According to the PFGE patterns, one strain of E. coli ST131 producing a CTX-M-15 enzyme carried by an IncF F2:A1:B- plasmid had spread within one DCC. CONCLUSIONS: This study shows a notable prevalence (6.4%) of DCC children with faecal CTX-M-producing E. coli isolates comprising a high proportion of E. coli ST131 isolates, suggesting that these children might be a reservoir of this clone.

Community-acquired Klebsiella pneumoniae pneumonia in ICU: a multicenter retrospective study.

BACKGROUND: Alongside the recent worldwide expansion of hypervirulent Klebsiella pneumoniae (KP) infections, the available literature regarding cases of community acquired pneumonias (KP-CAP) remains scarce but reports a strikingly high and early mortality. We performed a retrospective multicenter study (7 ICU in France) between 2015 and 2019, comparing prognosis and severity of KP-CAP versus Streptococcus pneumoniae - CAP (SP-CAP). METHODS: For each KP-CAP, three SP-CAP admitted in ICUs within the same center and within the same 6-month window were selected. When available, KP strains were studied, and bacterial virulence was genetically assessed for virulence factors. The primary outcome was in-hospital mortality. Associations between clinical outcomes and type of infection were tested using univariate and multivariate logistic regressions, adjusted for pairing variables. RESULTS: Twenty-seven KP-CAP and 81 SP-CAP were included. Respective in-hospital mortality rates were 59% (n = 16) and 17% (n = 14, p < 0.001), despite adequate antibiotic therapy. KP-CAP median time from admission to death was 26.9 h [IQR 5.75-44 h] and were significantly associated with higher rates of multiple organ failures (93% vs. 42%, p < 0.001), disseminated intravascular coagulation (12% vs. 1.3%, p = 0.046), septic shock (median lactate on ICU admission 4.60 vs. 2.90 mmol/L, p = 0.030) and kidney failure (KDIGO-3: 87% vs. 44%, p < 0.001). Interestingly, alcoholism was the only identified predisposing factor of KP-CAP. Severity on ICU admission (2-fold higher for KP-CAP) was the only factor associated with mortality in a multivariate analysis. CONCLUSION: We described a strong association between KP-CAP infection and higher and earlier mortality when compared to SP-CAP. Moreover, alcoholism was the sole predisposing factor associated with KP-CAP infection. These findings should raise awareness of clinicians involved in the management of severe CAP about this microbiological etiology. Future prospective studies are needed to confirm these results and to design strategies to improve the prognosis of such infections.

10-Fold increase (2006-11) in the rate of healthy subjects with extended-spectrum ß-lactamase-producing Escherichia coli faecal carriage in a Parisian check-up centre.

OBJECTIVES: In 2006, 0.6% of healthy subjects living in the Paris area had extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli in their gut. To assess the evolution of this rate, a study identical to that of 2006 was conducted in 2011. PARTICIPANTS AND METHODS: Healthy adults who visited the IPC check-up centre in February-March 2011 and agreed to participate, provided stools and answered a questionnaire on the visit day. Stools were analysed to detect ESBL producers and to isolate the dominant E. coli population. ESBLs were molecularly characterized. For the subjects harbouring ESBL-producing E. coli, the phylogenetic group and sequence type (ST) were determined for both ESBL-producing and dominant E. coli isolates. PFGE profiles were also determined when two types of isolates had the same ST. RESULTS: Among the 345 subjects included, 21 (6%) had ESBL-producing E. coli faecal carriage. None of the previously published risk factors was identified. CTX-M accounted for 86% and SHV-12 for 14%. Dominant and ESBL-producing E. coli were similarly distributed into phylogenetic groups (A, 52%-48%; B1, 5%; B2, 24%-14%; and D, 19%-33%). Dominant and ESBL-producing E. coli displayed a polyclonal structure (18 STs each). However, ST10 and ST131 were identified in dominant and ESBL-producing E. coli isolates from different subjects. Most (20/21) ESBL producers were subdominant and belonged (16/21) to STs different from that of the corresponding dominant E. coli. CONCLUSIONS: The 10-fold increase in the rate of healthy subjects with ESBL-producing E. coli faecal carriage over a 5 year period suggests wide dissemination of these isolates in the Parisian community.

[Clinical and radiological differences between amoebic and pyogenic liver abscess: A case-control study]. / Analyse des différences cliniques et radiologiques entre abcès hépatiques amibiens et à pyogènes à partir d'une étude cas-témoin.

INTRODUCTION: Amoebic liver abscess (ALA) is the fourth cause of mortality by parasitic infection. This study aimed to assess clinical, radiological and therapeutic characteristics of patients admitted for amoebic liver abscess compared to pyogenic abscess in a French digestive tertiary care-centre. MATERIAL AND METHOD: The charts of patients hospitalized for a liver abscess between 2010 and 2020 were retrospectively assessed then separated in two groups: amoebic liver abscess and pyogenic liver abscess from portal underlying cause. Clinical and radiological data were collected for univariate comparison. RESULTS: Twenty-one patients were hospitalized during the time of the study for ALA, and 21 patients for pyogenic liver abscess with a portal mechanism. All patients hospitalized for ALA lived in and/or had travelled recently in an endemic area. In comparison with patients hospitalized for pyogenic abscess, patients admitted for ALA were younger (44years old vs. 63years old, P<0.001), had less comorbidities (5% vs. 43% of patients with at least one comorbidity, P<0.01), a longer median duration of symptoms (10days vs. 3days, P=0.015), abdominal pain (86% vs. 52%, P=0.019), and a slighter leucocytosis (9600G/L vs. 15,500G/L, P=0.041) were more frequent. On the abdominal tomodensitometry, density of ALA was higher (34 vs. 25 UH, P<0.01), associated with a focal intra-hepatic biliary dilatation and less often multiloculated. CONCLUSION: While rare in western countries, amoebic liver abscess care should not be underestimated. The presence of a solitary liver abscess of intermediate density on computed tomography, occurring on a patient returning from an endemic zone should lead the physician to a possible diagnosis of ALA.

Three-month antibiotic therapy for early-onset postoperative spinal implant infections.

BACKGROUND: Optimal duration and modalities of antibiotic therapy for early-onset spinal implant infection (EOSII) remain controversial. METHODS: Between November 2004 and November 2007, we conducted a prospective, monocentric study to assess the efficacy of a 3-month course of antibiotics for patients diagnosed with EOSII, as defined by a proven deep infection of the surgical site occurring within 30 days after spinal instrumented surgery. All patients with EOSII underwent surgical debridement with implant retention. Combination antibiotic therapy was administered intravenously for 2 weeks. Treatment was switched orally for the following 10 weeks. RESULTS: 50 patients matched the inclusion criteria and were included in this study. The median age was 68 (interquartile range [IQR]: 51-75) years; the median ASA score was 2 (IQR: 2-2). Emergency spinal surgery had been performed in 18 patients. Staphylococcus aureus was the most frequently isolated pathogen (n=27), followed by Enterobacteriaceae (n=22) and coagulase-negative staphylococci (n=6). Seventeen patients had polymicrobial infections, and 13 patients (26%) had bacteremia. The median time from the first symptoms of infection to debridement surgery was 3 days (IQR: 2-5 days). Three patients underwent 2 debridement surgeries. The median follow-up was 43 (IQR: 34-54) months. The 2-year survival rate for those who did not experience treatment failure was 88% (95% confidence interval [CI]: 75.7%-95.5%). Three patients experienced treatment failure (6%, 95% CI: 1.3%-16.5%), including 1 relapse due to methicillin-susceptible S. aureus and 2 reinfections with another pathogen. CONCLUSIONS: In this homogenous cohort of 50 patients with EOSII, treatment consisting of debridement surgery with implant retention followed by combination antibiotic therapy for 3 months appeared safe and effective.

Phylogenetic distribution of CTX-M- and non-extended-spectrum-ß-lactamase-producing Escherichia coli isolates: group B2 isolates, except clone ST131, rarely produce CTX-M enzymes.

Escherichia coli is the species most frequently associated with clinical infections by extended-spectrum-ß-lactamase (ESBL)-producing isolates, with the CTX-M ESBL enzymes being predominant and found in genetically diverse E. coli isolates. The main objective of this study was to compare, on the basis of a case-control design, the phylogenetic diversity of 152 CTX-M-producing and 152 non-ESBL-producing clinical E. coli isolates. Multilocus sequence typing revealed that even though CTX-M enzymes were largely disseminated across the diversity of E. coli isolates, phylogenetic group B2 showed a particularly heterogeneous situation. First, clone ST131 of group B2 was strongly associated with CTX-M production (55 [79%] of 70 isolates), with CTX-M-15 being predominant. Second, the remaining members of group B2 were significantly less frequently associated with CTX-M production (9 [12%] of 75) than E. coli phylogenetic groups A, B1, and D (88 [55%] of 159). CTX-M-producing ST131 E. coli isolates were significantly more frequent in patients hospitalized in geriatric wards or long-term care facilities. Besides, the non-ESBL ST131 isolates significantly more frequently showed resistance to penicillins than the non-ESBL, non-ST131 isolates did. In conclusion, the present study emphasizes the particular antimicrobial resistance and epidemiologic characteristics of clone ST131 within group B2, which could result from the higher antibiotic exposure of this clone, as it is the predominant clone of group B2 carried in the human gut.

Spontaneous and postsurgical/traumatic Klebsiella pneumoniae meningitis: two distinct clinico-microbiological entities.

OBJECTIVES: To analyze and compare the characteristics and outcomes of spontaneous meningitis (SM) versus postsurgical/traumatic meningitis (PSTM) due to Klebsiella pneumoniae. METHODS: A retrospective multicentric cohort study of all K. pneumoniae meningitis cases managed between January 2007 and May 2018 was carried out in seven university hospitals in the Paris area. The microbiological characteristics of 16 available K. pneumoniae isolates were further analyzed, and the genomes of seven of those isolated from SM were sequenced. RESULTS: Among 35 cases, 10 were SM and 25 were PSTM. SM cases more severe than PSTM cases, with higher septic shock (p = 0.004) and in-hospital mortality rates (p = 0.004). In contrast, relapse occurred in five patients from the PSTM group versus no patients from the SM group. All K. pneumoniae strains recovered from SM but none of those recovered from PSTM displayed hypervirulent phenotypic (positive string test) and genotypic (genes corresponding to capsular serotypes K1 or K2; virulence genes rmpA and iutA) characteristics (p < 0.0001). PSTM tended to be more frequently polymicrobial (p = 0.08) and caused by an extended-spectrum ß-lactamase producing strain (p = 0.08) than SM. CONCLUSIONS: SM and PSTM are two entities differing both from a clinical and a microbiological standpoint. SM appears to be a more serious infection, induced by hypervirulent K. pneumoniae strains.

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.

In vitro selection of ramR and soxR mutants overexpressing efflux systems by fluoroquinolones as well as cefoxitin in Klebsiella pneumoniae.

The relationship between efflux system overexpression and cross-resistance to cefoxitin, quinolones, and chloramphenicol has recently been reported in Klebsiella pneumoniae. In 3 previously published clinical isolates and 17 in vitro mutants selected with cefoxitin or fluoroquinolones, mutations in the potential regulator genes of the AcrAB efflux pump (acrR, ramR, ramA, marR, marA, soxR, soxS, and rob) were searched, and their impacts on efflux-related antibiotic cross-resistance were assessed. All mutants but 1, and 2 clinical isolates, overexpressed acrB. No mutation was detected in the regulator genes studied among the clinical isolates and 8 of the mutants. For the 9 remaining mutants, a mutation was found in the ramR gene in 8 of them and in the soxR gene in the last one, resulting in overexpression of ramA and soxS, respectively. Transformation of the ramR mutants and the soxR mutant with the wild-type ramR and soxR genes, respectively, abolished overexpression of acrB and ramA in the ramR mutants and of soxS in the soxR mutant, as well as antibiotic cross-resistance. Resistance due to efflux system overexpression was demonstrated for 4 new antibiotics: cefuroxime, cefotaxime, ceftazidime, and ertapenem. This study shows that the ramR and soxR genes control the expression of efflux systems in K. pneumoniae and suggests the existence of efflux pumps other than AcrAB and of other loci involved in the regulation of AcrAB expression.

Detection of bacterial DNA in serum and ascitic fluid of asymptomatic outpatients with cirrhosis and non-neutrocytic ascites.

BACKGROUND AND AIMS: Bacterial DNA (bactDNA) has been found in serum and ascitic fluid (AF) of 30-40% of hospitalized patients with cirrhosis and non-neutrocytic ascites, but its prevalence in outpatients is unknown. The aim of this prospective study was to investigate the presence of bactDNA in AF and serum among cirrhotic outpatients with non-neutrocytic ascites. METHODS: Thirty-one consecutive patients with cirrhosis and non-neutrocytic ascites, who underwent therapeutic paracentesis in our outpatient clinic, were enrolled over a 13-week period. Of these patients, 13 had a single paracentesis and 18 patients had several consecutive paracenteses (2-10) over the study period. Overall, 98 serum and non-neutrocytic AF specimens were obtained and tested for the presence of bactDNA by polymerase chain reaction amplification of the 16S ribosomal RNA gene. RESULTS: The main causes of cirrhosis were alcohol (53.5%) and hepatitis C (30%). The median MELD score was 16 and there were 54.8% Child-Pugh C patients. BactDNA was negative in all samples from 28 of the 31 patients, including 15 patients with several paracentesis. One patient had a single AF sample culture positive and bactDNA positive for Streptococcus mitis, whereas the simultaneous blood sample was negative. For each of the last two patients, DNA from Lactococcus lactis was detected in a single blood sample but not in the simultaneous AF sample. CONCLUSIONS: In contrast to that reported previously in hospitalized patients, bactDNA is rarely detected in serum and AF of outpatients with cirrhosis and non-neutrocytic ascites.

Endocarditis caused by Thalassospira sp.

We report a case of an infective endocarditis caused by a Thalassospira sp. in a 53-year-old man with pre-existing valvular lesions and living in French Polynesia as a fisherman. The strain was identified with DNA-sequecing methods while it was not by mass spectrometry.

A prospective, observational study of fidaxomicin use for Clostridioides difficile infection in France.

OBJECTIVE: To describe the characteristics, management and outcomes of hospitalised patients with Clostridioides difficile infection (CDI) treated with and without fidaxomicin. METHODS: This prospective, multicentre, observational study (DAFNE) enrolled hospitalised patients with CDI, including 294 patients treated with fidaxomicin (outcomes recorded over a 3-month period) and 150 patients treated with other CDI therapies during three 1-month periods. The primary endpoint was baseline and CDI characteristics of fidaxomicin-treated patients. RESULTS: At baseline, the fidaxomicin-treated population included immunocompromised patients (39.1%) and patients with severe (59.2%) and recurrent (36.4%) CDI. Fidaxomicin was associated with a high rate of clinical cure (92.2%) and low CDI recurrence (16.3% within 3 months). Clinical cure rates were ≥90% in patients aged ≥65 years, those receiving concomitant antibiotics and those with prior or severe CDI. There were 121/296 (40.9%) patients with adverse events (AEs), 5.4% with fidaxomicin-related AEs and 1.0% with serious fidaxomicin-related AEs. No fidaxomicin-related deaths were reported. CONCLUSIONS: Fidaxomicin is an effective and well-tolerated CDI treatment in a real-world setting in France, which included patients at high risk of adverse outcomes.Trial registration: Description of the use of fidaxomicin in hospitalised patients with documented Clostridium difficile infection and the management of these patients (DAFNE), NCT02214771, www.ClinicalTrials.gov.

Membrane efflux and influx modulate both multidrug resistance and virulence of Klebsiella pneumoniae in a Caenorhabditis elegans model.

Cross-resistance to cefoxitin (FOX), chloramphenicol (CMP), and quinolones (nalidixic acid [NAL]) related to a putative efflux system overexpression has recently been reported for Klebsiella pneumoniae. The potential impact of this multidrug resistance (MDR) on the virulence of K. pneumoniae was evaluated in the Caenorhabditis elegans model. For 2 of the 3 MDR clinical isolates studied, a significant increase in acrB transcription was found in comparison with their antibiotic-susceptible revertants. ATCC 138821 and MDR, revertant, and derivative strains with altered porin expression were studied. Strains proved or suspected to overexpress an efflux system were significantly more virulent than the ATCC and revertant strains (time to kill 50% of nematodes [LT(50)] in days: 3.4 to 3.8 ± 0.2 versus 4.1 to 4.4 ± 0.3, P < 0.001). Inversely, strains with altered porin expression were significantly less virulent, independently of the expression level of efflux system (LT(50) = 5.4 to 5.6 ± 0.2, P < 0.001). Altered porin expression did not change MICs of CMP and NAL but did those of FOX (4 to 16× MIC) and ertapenem (16 to 64× MIC). The strains with a normally or an overexpressed efflux system that received the ß-lactamase CTX-M-15 became more widely resistant without modification of their virulence potential, suggesting that balance between resistance and virulence is dependent on the type of resistance mechanisms. In conclusion, this study shows that the expression of both efflux systems and porins is a key factor not only for antibiotic resistance but also virulence potential in K. pneumoniae.

Broad-range 16S rRNA PCR with cerebrospinal fluid may be unreliable for management of postoperative aseptic meningitis.

We previously demonstrated that discontinuing presumptive antibiotic treatment in cases of negative conventional cultures is safe and effective for patients with postoperative aseptic meningitis (PAM). Here, we prospectively investigated 32 patients with postoperative meningitis. All 26 patients with PAM diagnosed on the basis of conventional cultures demonstrated negative 16S rRNA PCR results. Our results suggest that the PCR technique does not change PAM management.