Increased incidence of Campylobacter jejuni-associated Guillain-Barré syndromes in the Greater Paris area.

The role of Campylobacter jejuni as the triggering agent of Guillain-Barré syndrome (GBS) has not been reassessed since the end of the 1990s in France. We report that the number of C. jejuni-related GBS cases increased continuously between 1996 and 2007 in the Paris region (mean annual increment: 7%, P = 0·007).

Diversity, community composition, and dynamics of nonpigmented and late-pigmenting rapidly growing mycobacteria in an urban tap water production and distribution system.

Nonpigmented and late-pigmenting rapidly growing mycobacteria (RGM) have been reported to commonly colonize water production and distribution systems. However, there is little information about the nature and distribution of RGM species within the different parts of such complex networks or about their clustering into specific RGM species communities. We conducted a large-scale survey between 2007 and 2009 in the Parisian urban tap water production and distribution system. We analyzed 1,418 water samples from 36 sites, covering all production units, water storage tanks, and distribution units; RGM isolates were identified by using rpoB gene sequencing. We detected 18 RGM species and putative new species, with most isolates being Mycobacterium chelonae and Mycobacterium llatzerense. Using hierarchical clustering and principal-component analysis, we found that RGM were organized into various communities correlating with water origin (groundwater or surface water) and location within the distribution network. Water treatment plants were more specifically associated with species of the Mycobacterium septicum group. On average, M. chelonae dominated network sites fed by surface water, and M. llatzerense dominated those fed by groundwater. Overall, the M. chelonae prevalence index increased along the distribution network and was associated with a correlative decrease in the prevalence index of M. llatzerense, suggesting competitive or niche exclusion between these two dominant species. Our data describe the great diversity and complexity of RGM species living in the interconnected environments that constitute the water production and distribution system of a large city and highlight the prevalence index of the potentially pathogenic species M. chelonae in the distribution network.

Specific real-time PCR for simultaneous detection and identification of Legionella pneumophila serogroup 1 in water and clinical samples.

Legionella pneumophila, a bacterium that replicates within aquatic amoebae and persists in the environment as a free-living microbe, is the causative agent of Legionnaires' disease. Among the many Legionella species described, L. pneumophila is associated with 90% of human disease, and within the 15 serogroups (Sg), L. pneumophila Sg1 causes more than 84% of Legionnaires' disease worldwide. Thus, rapid and specific identification of L. pneumophila Sg1 is of the utmost importance for evaluation of the contamination of collective water systems and the risk posed. Previously we had shown that about 20 kb of the 33-kb locus carrying the genes coding for the proteins involved in lipopolysaccharide biosynthesis (LPS gene cluster) by L. pneumophila was highly specific for Sg1 strains and that three genes (lpp0831, wzm, and wzt) may serve as genetic markers. Here we report the sequencing and comparative analyses of this specific region of the LPS gene cluster in L. pneumophila Sg6, -10, -12, -13, and -14. Indeed, the wzm and wzt genes were present only in the Sg1 LPS gene cluster, which showed a very specific gene content with respect to the other five serogroups investigated. Based on this observation, we designed primers and developed a classical and a real-time PCR method for the detection and simultaneous identification of L. pneumophila Sg1 in clinical and environmental isolates. Evaluation of the selected primers with 454 Legionella and 38 non-Legionella strains demonstrated 100% specificity. Sensitivity, specificity, and predictive values were further evaluated with 209 DNA extracts from water samples of hospital water supply systems and with 96 respiratory specimens. The results showed that the newly developed quantitative Sg1-specific PCR method is a highly specific and efficient tool for the surveillance and rapid detection of high-risk L. pneumophila Sg1 in water and clinical samples.

The inlAB locus mediates the entry of Listeria monocytogenes into hepatocytes in vivo.

The intracellular parasite Listeria monocytogenes is able to induce its internalization by cultured mammalian cells that are not normally phagocytic. This process requires the expression of the chromosomal locus inlAB. We studied the virulence of an inlAB mutant and of its parent in murine listeriosis. Irrespective of the route of inoculation, the inlAB mutant was severely attenuated for growth in the liver. The livers of mice inoculated with the inlAB mutant displayed much smaller infectious foci than the parent as early as 24 h after infection. Electron microscopy showed that these foci consisted of a few inflammatory cells, with few bacteria; bacteria were rarely found within hepatocytes. In contrast, foci in livers of mice inoculated with the parent consisted of islets of heavily infected hepatocytes that were infiltrated by numerous neutrophils; bacteria seemed intact within hepatocytes and damaged within neutrophils. A direct role of inlAB for the entry of L. monocytogenes into hepatocytes was confirmed in a cell infection system using the murine embryonic hepatocyte cell line TIB73. The inlAB mutant was approximately 20-fold less invasive in trans. The "invasion locus" inlAB contributes to protect L. monocytogenes from the host's innate defense mechanisms by promoting its entry into hepatocytes.

Inhibitory effect of αS1- and αS2-casein hydrolysates on angiotensin I-converting enzyme in human endothelial cells in vitro, rat aortic tissue ex vivo, and renovascular hypertensive rats in vivo.

A great number of milk-derived peptides have been shown to exhibit angiotensin converting enzyme (ACE) inhibitory properties and thus potential utility in the regulation of blood pressure. The present work aimed to investigate the effects of 2 milk trypsin hydrolysates from alpha(S1)- and alpha(S2)-casein (CH1 and CH2, respectively) on ACE activity evaluated in human umbilical vein endothelial cells (HUVEC) in vitro, rat aortic tissues ex vivo, and renovascular hypertensive rat in vivo. Incubation of HUVEC and rat aortic tissues with CH1 or CH2 induced a concentration-dependent inhibition of hydrolysis of the ACE substrate hippuryl-histidyl-leucine (HHL), the hydrolysates being much less potent than perindopril (an ACE inhibitor). However, in contrast to perindopril, CH1 and CH2 failed to modify angiotensin I-induced aortic ring vasoconstriction. The HPLC profiles of rat plasma after intragastric administration were variable among individuals but none of the observed peaks corresponded to peptides comprising CH1 or CH2 or to fragments of these peptides. During 4 wk of cardiovascular monitoring, in hydrolysate-fed renovascular hypertensive rats, systolic blood pressure weakly decreased compared with the control group. However, the CH1-fed hypertensive rats exhibited a decrease of heart rate during the nocturnal period of activity. To conclude, our results show that CH1 and CH2 inhibited ACE activity in HUVEC and rat aortic tissue but failed to antagonize the aortic-constricting effects of the natural agonist angiotensin I. Moreover, we demonstrated that CH1, to a greater extent than CH2, can slightly affect cardiovascular parameters although the ingested bioactive peptides could not be detected in the blood.

Case series of carbapenemase-producing Enterobacteriaceae osteomyelitis: Feel it in your bones.

OBJECTIVES: Limited data have been reported regarding osteomyelitis due to carbapenemase-producing Enterobacteriaceae (CPE), including co-infections with extended-spectrum ß-lactamase (ESBL)-producing micro-organisms. METHODS: We conducted a retrospective study in a reference centre for bone and joint infections from 2011 to 2019 among patients infected with CPE. RESULTS: Nine patients (mean age 46.8 ± 16.6 years), including three with infected implants, were identified. Infections were mostly polymicrobial (n = 8/9), including Staphylococcus aureus (n = 6/9). CPE were mainly OXA-48-type, associated with ESBL-producing Enterobacteriaceae (n = 8/9), of which 5/9 isolates were Klebsiella pneumoniae. Control of the infection was achieved in seven cases. CONCLUSIONS: CPE osteomyelitides are essentially polymicrobial and fluoroquinolone-resistant infections, highlighting the need for efficient surgery with implant removal.

Partial atlE sequencing of Staphylococcus epidermidis strains from prosthetic joint infections.

Partial atlE sequencing (atlE nucleotides 2782 to 3114 [atlE(2782-3114)]) was performed in 41 Staphylococcus epidermidis isolates from prosthetic joint infections (PJIs) and 44 isolates from skin as controls. The atlE(2782-3114) allele 1 (type strain sequence) was significantly more frequent in PJI strains (38/41 versus 29/44 in controls; P = 0.0023). Most PJI strains were positive for mecA, icaA/icaD, and IS256, and most belonged to the sequence type 27 subgroup, suggesting the involvement of few related clones.

Equine alpha S1-casein: characterization of alternative splicing isoforms and determination of phosphorylation levels.

alpha(S1)-Casein was isolated from Haflinger mare's milk by hydrophobic interaction chromatography and displayed great micro-heterogeneity by 2-dimensional electrophoresis, probably because of a variable degree of phosphorylation and alternative splicing events. The aim of the present work was to investigate the complexity of the mare's alpha(S1)-casein. The different isoforms present in milk were submitted to a double treatment of dephosphorylation, first by using alkaline phosphatase and then acid phosphatase to achieve complete dephosphorylation. The apoforms were then analyzed by electrospray ionization mass spectrometry. The results revealed the existence of a full-length protein and 7 variants resulting from posttranscriptional modifications; that is, exon skipping involving exon 7, exon 14, or both and use of a cryptic splice site encoding a glutamine residue. The determination of the different phosphorylation degrees of the native isoforms of alpha(S1)-casein was finally achieved by electrospray ionization mass spectrometry analysis after fractionation of the isoforms by ion-exchange chromatography. Thus, 36 different variants of equine alpha(S1)-casein were identified with several phosphate groups ranging from 2 to 6 or 8 depending on whether exon 7 was skipped.

Two-dimensional cartography of equine beta-casein variants achieved by isolation of phosphorylation isoforms and control of the deamidation phenomenon.

Because of variable degrees of phosphorylation, alternative splicing, and probable instability resulting from nonenzymatic deamidation, equine beta-casein presents a complex pattern by 2-dimensional electrophoresis that needs clarification. beta-Casein prepared from Haflinger mare's milk by hydrophobic interaction chromatography was fractionated by ion-exchange chromatography according to the degree of phosphorylation. Isoforms were identified by mass spectrometry; they corresponded to the full-length protein having 3 to 7 phosphate groups and to the splicing variant involving exon 5 and containing 4 to 7 phosphate groups. Investigations of nonenzymatic deamidation showed that beta-casein did not deamidate spontaneously in stored milk and during the different steps of chromatography, but deamidation could occur when 2-dimensional electrophoresis was performed, increasing the beta-casein pattern complexity. This phenomenon was strongly minimized when the first dimension step was carried out at 10 degrees C instead of at room temperature. Finally, spot attribution on 2-dimensional pattern of beta-casein was achieved by mixing each phosphorylation isoform in its native state with the whole beta-casein fraction.

Urinary tract infections in patients with neurogenic bladder.

Urinary tract infections (UTIs) in patients with neurogenic bladder are a major public health issue due to their high incidence and major consequences. Despite their frequency and potential severity, their physiopathology and management are poorly known. We provide a narrative literature review on the epidemiology, physiopathology, diagnostic criteria, microbiology, antimicrobial management, and prevention. UTIs among patients with neurogenic bladder are associated with high morbidity and healthcare utilization. Risk factors for UTI among this population are: indwelling catheter, urinary stasis, high bladder pressure, and bladder stones. Their diagnosis is a major challenge as clinical signs are often non-specific and rare. A urinary sample should be analyzed in appropriate conditions before any antibiotic prescription. According to most guidelines, a bacterial threshold≥103CFU/ml associated with symptoms is acceptable to define UTI in patients with neurogenic bladder. The management of acute symptomatic UTI is not evidence-based. A management with a single agent and a short antibiotic treatment of 10 days or less seems effective. Antibiotic selection should be based on the patient's resistance patterns. Asymptomatic bacteriuria should not be treated to avoid the emergence of bacterial resistance. Regarding preventive measures, use of clean intermittent catheterization, intravesical botulinum toxin injection, and prevention using antibiotic cycling are effective. Bacterial interference is promising but randomized controlled trials are needed. Large ongoing cohorts and randomized controlled trials should soon provide more evidence-based data.

[Clinical presentation and performance of urine dipstick for diagnosis of urinary infection in geriatric population]. / Présentation clinique et performance de la bandelette urinaire pour le diagnostic d'infection urinaire en population gériatrique.

BACKGROUND: Urinary tract infections (UTI) are the second cause of community-acquired bacterial infections in the elderly. Distinguishing symptomatic UTI from asymptomatic bacteriuria is problematic, as older adults are less likely to present with localized urinary symptoms. We evaluated characteristics of patients presenting UTI among elderly with sepsis. Moreover, we aimed to evaluate the sensibility and specificity of urine dipstick tests in the diagnosis of UTI in geriatric population. PATIENTS AND METHOD: We led a prospective, monocentric, observational study between April 2017 and January 2018. We included patients hospitalized in geriatric wards, who were prescribed urine culture for UTI symptoms or/and infection without primary sites for which a urine culture was prescribed. Dipstick urinalyses were performed for all patients. Clinical and biological characteristics of all patients were compared according to the final diagnosis of UTI. Moreover, results of dipstick tests were evaluated for the diagnosis of UTI in this population. RESULTS: Among 165 patients, 67 (40.6 %) had a UTI and 98 (59.4 %) had another diagnosis. These two groups were comparable for age and daily-living activities. In the UTI group, the proportion of women was higher than in the other group (P<0.05), and mean MMSE score was lower (P<0.05). Positive urine dipstick test for leukocytes and/or nitrites had high sensitivity (92 %), but low specificity (50 %). Negative predictive value of this test was high (91 %). CONCLUSION: For suspicion of UTI among elderly, few criteria are specific. Negative dipstick tests can suggest an absence of UTI due to its high negative predictive value.

Partial interferon-gamma receptor 1 deficiency in a child with tuberculoid bacillus Calmette-Guérin infection and a sibling with clinical tuberculosis.

Complete interferon-gamma receptor 1 (IFNgammaR1) deficiency has been identified previously as a cause of fatal bacillus Calmette-Guérin (BCG) infection with lepromatoid granulomas, and of disseminated nontuberculous mycobacterial (NTM) infection in children who had not been inoculated with BCG. We report here a kindred with partial IFNgammaR1 deficiency: one child afflicted by disseminated BCG infection with tuberculoid granulomas, and a sibling, who had not been inoculated previously with BCG, with clinical tuberculosis. Both responded to antimicrobials and are currently well without prophylactic therapy. Impaired response to IFN-gamma was documented in B cells by signal transducer and activator of transcription 1 nuclear translocation, in fibroblasts by cell surface HLA class II induction, and in monocytes by cell surface CD64 induction and TNF-alpha secretion. Whereas cells from healthy children responded to even low IFN-gamma concentrations (10 IU/ml), and cells from a child with complete IFNgammaR1 deficiency did not respond to even high IFN-gamma concentrations (10,000 IU/ml), cells from the two siblings did not respond to low or intermediate concentrations, yet responded to high IFN-gamma concentrations. A homozygous missense IFNgR1 mutation was identified, and its pathogenic role was ascertained by molecular complementation. Thus, whereas complete IFNgammaR1 deficiency in previously identified kindreds caused fatal lepromatoid BCG infection and disseminated NTM infection, partial IFNgammaR1 deficiency in this kindred caused curable tuberculoid BCG infection and clinical tuberculosis.

Control of an ACC-1-producing Klebsiella pneumoniae outbreak in a physical medicine and rehabilitation unit.

This article describes an outbreak of ACC-1-producing Klebsiella pneumoniae involving 40 patients. These were mainly men under 40 years old with a spinal cord injury, in a physical medicine and rehabilitation unit. The main risk factors were prolonged hospital stay, multiple-bed rooms, tracheostomy care and assisted defaecation. The outbreak was only controlled after the introduction of rigorous patient placement (i.e. single rooms or cohorting in the same room), while allowing the patients to have free access to the various technical services (e.g. physiotherapy and occupational therapy) and living spaces necessary for re-education.

[Campylobacter jejuni and cytomegalovirus (CMV) infections in patients with the Guillain-Barre syndrome]. / Infections à Campylobacter jejuni et à cytomégalovirus (CMV) associées au syndrome de Guillain-Barré (SGB).

Guillain-Barre syndrome (GBS) is a rare disease triggered by postinfectious mechanisms. The disease concerns all ages, and is widely distributed around the world. The principal risks are respiratory failure, especially during the initial phase of the disease, and persisting deficit at long term. Among the infectious known agents, Campylobacter jejuni and CMV represent more than 40% of GBS causes. The clinical presentation, and the long-term prognosis of GBS related to these two etiologies are different. The physiopathological mechanisms of the nervous attack are probably also different. There is no proof, at this time, that anti-infectious treatment can improve the prognosis. The treatment is based on the early use of immunomodulatory treatments like intravenous immunoglobulins or plasma exchanges.

Vaccine strategies against bacterial pathogens in cystic fibrosis patients.

A large number of cystic fibrosis pathogens such as bacteria of the Burkholderia cepacia complex, Pseudomonas aeruginosa, or Mycobacterium abscessus are associated with complex therapeutic problems due to their inherent resistance to antibiotics. No vaccine is currently available against those pathogens. Vaccines are therefore crucial to combat these multidrug-resistant bacteria in specific clinical situations including cystic fibrosis. Various strategies may be considered to develop these vaccines. Similar virulence factors are expressed during the infection with various pathogens; they could thus be used as antigen to assess cross-protection. Many clinical trials are currently being conducted to try and develop a prophylactic treatment for patients presenting with cystic fibrosis.

Evaluating antibiotic therapies prescribed to adult patients in the emergency department.

OBJECTIVES: The proper use of antibiotics is a public health priority to preserve their effectiveness. Little data is available on outpatient antibiotic prescriptions, especially in the emergency department. We aimed to assess the quality of outpatient antibiotic prescriptions in our hospital. PATIENTS AND METHODS: Retrospective monocentric study of antibiotic prescriptions written to adult patients managed at the emergency department without hospitalization (November 15th, 2012-November 15th, 2013). Prescriptions were evaluated by an infectious disease specialist and an emergency physician on the basis of local recommendations compiled from national and international guidelines. RESULTS: A total of 760 prescriptions were reviewed. The most frequent indications were urinary tract infections (n=263; 34.6%), cutaneous infections (n=198; 26.05%), respiratory tract infections (n=101; 13.28%), and ENT infections (n=62; 8.15%). The most frequently prescribed antibiotics were fluoroquinolones (n=314; 40.83%) and amoxicillin-clavulanic acid (n=245; 31.85%). Overall, 455 prescriptions (59.86%) did not comply with guidelines. The main reasons for inadequacy were the absence of an indication for antibiotic therapy (n=197; 40.7%), an inadequate spectrum of activity, i.e. too broad, (n=95; 19.62%), and excessive treatment duration (n=87; 17.97%). Rates of inadequate prescriptions were 82.26% for ENT infections, 71.2% for cutaneous infections, 46.53% for respiratory tract infections, and 38.4% for urinary tract infections. CONCLUSION: Antibiotic prescriptions written to outpatients in the emergency department are often inadequate. Enhancing prescribers' training and handing out guidelines is therefore necessary. The quality of these prescriptions should then be re-assessed.

Specific inhibition of phosphatidate cytidylyltransferase from Bacillus subtilis membranes by cytidine monophosphate.

In Bacillus subtilis, the phosphatidate cytidylyltransferase was localized exclusively in the membrane fraction prepared by sucrose density gradient fractionation. A single enzyme could synthesize the two liponucleotides: CDPdiacylglycerol and dCDPdiacylglycerol. Kinetic experiments and isotopic exchange reactions suggested a ping-pong mechanism. Among the nucleosides monophosphate, CMP specifically reduced the synthesis of both liponucleotides. This inhibition was non-competitive and might be involved in regulation of phospholipid synthesis.

Evidence for membrane affinity of the C-terminal domain of bovine milk PP3 component.

Component PP3 is a phosphoglycoprotein isolated from bovine milk with unknown biological function, which displays in its C-terminal region a basic amphipathic alpha-helix, a feature often involved in membrane association. According to that, the behaviour of PP3 and of a synthetic peptide from the C-terminal domain (residues 113-135) was investigated in lipid environment. Conductance measurements indicated that the peptide was able to associate and form channels in planar lipid bilayers composed of neutral or charged phospholipids. Electrostatic interactions seemed to promote voltage-dependent channel formation but this was not absolutely required since the pore-forming ability of the 113-135 C-terminal peptide was also detected with the zwitterionic lipid bilayer. Additionally, a spectroscopic study using circular dichroism argues that the peptide adopts an alpha-helical conformation in interaction with neutral or charged micelles. Thus, the conducting aggregates in bilayers might be composed of a bundle of peptides in helical conformation. Besides, similar conductance measurements performed with the whole PP3 protein did not induce any channel fluctuations. However, with the latter, an early breakdown of the bilayers occurred, a finding that can be tentatively explained by a massive incorporation of PP3. In the light of the present results, it could be inferred that PP3 membrane attachment may be achieved by oligomerization of the C-terminal amphipathic helical region.

[Nontuberculous mycobacteria in cystic fibrosis]. / Mycobactéries atypiques et mucoviscidose.

Patients with cystic fibrosis are particularly at risk of infection with non-tuberculous mycobacteria (NTM). Prevalence of these infections increases with age to around 15 %. The main species involved are M. abscessus and M. avium, the latter not found in children under 15. Diagnosis relies on clinical, radiological and above all bacteriological criteria defined by the ATS. Identification of the causal species of NTM is essential and requires genetic techniques, some of which are currently evaluated. Treatment depends on the mycobacterial species. For M. avium, combined therapy with rifampicin, clarithromycin and ethambutol must be extended 12 months after negativation. M. abscessus infection is particularly resistant to therapy. Usual treatment is a one month course of intravenous imipenem or cefoxitin plus amikacin followed by oral clarithromycin plus ethambutol for at least 12 months after negativation. In case of local lesions, surgery is an option.