Metronidazole resistance in Prevotella spp. and description of a new nim gene in Prevotella baroniae.

Nonduplicate clinical isolates of Prevotella spp. recovered from patients hospitalized between 2003 and 2006 in two French tertiary-care teaching hospitals were investigated for their susceptibility to metronidazole and the presence of nim genes. Of the 188 strains tested, 3 isolates displayed reduced susceptibility to metronidazole after 48 h of incubation, while 27 additional isolates exhibited heterogeneous resistance after prolonged incubation; all 30 of the isolates were nim negative. Among the remaining 158 isolates, 7 nim-positive isolates were detected. All of these strains were identified as Prevotella baroniae by 16S rRNA gene sequence analysis and contained a new nim gene, named nimI, as determined by DNA sequence analysis. Chromosomal localization of this single-copy gene was demonstrated in all clinical isolates as well as in type strain P. baroniae DSM 16972 by using Southern hybridization. No known associated insertion sequence elements were detected upstream of the nimI gene in any of the nim-positive strains by PCR mapping. After prolonged exposure to metronidazole, stable resistant subpopulations could be selected in nimI-positive Prevotella isolates (n = 6) as well as in nim-negative Prevotella isolates (n = 6), irrespective of their initial susceptibility to this antibiotic. This study is the first description of a new nitroimidazole resistance gene in P. baroniae which seems to be silent and which might be intrinsic in this species. Moreover, our findings highlight the fact that high-level resistance to metronidazole may be easily induced in both nim-positive and nim-negative Prevotella sp. strains.

Effectiveness of antibacterial prophylaxis in children with acute leukemia: A report from a single institution over a 20-year period.

BACKGROUND: Infection is the major cause of treatment-related mortality in childhood acute leukemia, mainly due to bacterial translocation across the intestinal mucosa. Only a few studies have reported the impact of different antibacterial prophylaxis treatments on digestive tract flora and infection-related mortality. PROCEDURES: We performed a retrospective analysis of two different digestive tract decontamination modalities (selective or total digestive decontamination) in a large single-center series of 323 children during the induction treatment of acute leukemia between January 1995 and December 2014. We examined the impact of antibiotic prophylaxis and food regimen (sterile or selected) on the digestive tract flora during the period of antibacterial prophylaxis, on the frequency of bacteremia, and on antibiotic sensitivity. RESULTS: Only one Gram-negative (Klebsiella pneumonia) translocation occurred in the SDD group. No infection-related death occurred. Extended-spectrum beta-lactamase (ESBL) bacteria were observed in seven of 170 (4%) patients in the SDD group. The faecal-flora total suppression and faecal-flora Gram-negative bacilli suppression was 67 and 77%, respectively, in the TDD group with sterile food, 0 and 58%, respectively, in the SDD group with sterile food, and 6 and 63%, respectively, in the SDD group with selective food. CONCLUSIONS: This study gives a rationale not to use antibacterial prophylaxis systematically in children who receive induction treatment for acute leukemia; additionally, antibiotics should only be used in case of stool contamination by highly pathogenic bacteria with a high potential of translocation.

Antimicrobial susceptibilities of Pasteurella strains isolated from humans.

The in vitro susceptibilities of 192 consecutive clinical strains of Pasteurella spp. isolated between 1996 and 2003 from soft tissue pus (n = 146), respiratory tract specimens (n = 38) and blood (n = 8) were studied by an agar dilution method. All isolates were susceptible to minocycline, cefotaxime, ofloxacin, ciprofloxacin and levofloxacin. Most strains were susceptible to moxifloxacin, amoxicillin, azithromycin and clarithromycin, whereas lower susceptibility rates to telithromycin (89.4%) were observed among respiratory tract isolates.

Gastric diffusion of antibiotics used against Helicobacter pylori.

Only a few pharmacological studies have been carried out on men and guinea pigs to determine the gastric diffusion of antibiotics, which are active against Helicobacter pylori. The results of these studies have been analysed in considering the physicochemical nature, the mode of administration, the way of gastric diffusion (topic and/or systemic) and the pharmacological interactions. The correlation of these pharmacokinetic results with those obtained in clinical trials is difficult because of the heterogeneity of the pharmacological and pharmacodynamic data. The absence of a convenient and suitable animal or in vitro study model renders further standardized pharmacokinetic studies in infected man and at steady state necessary.

Survey of anaerobic susceptibility patterns: a French multicentre study.

In 1996, the in vitro antibiotic susceptibility of 463 anaerobes was measured in five hospitals using the reference agar dilution method. None of the 209 B. fragilis group strains showed resistance to imipenem or ticarcillin-clavulanic acid. High resistance rates (29%) were observed for cefotetan and clindamycin. beta-Lactamase production was detected respectively in 64% of the Prevotella and 7% of the Fusobacterium strains. Because the same standardized methods were used for many years, the authors were able to evaluate the evolution of antibiotic resistance. Clindamycin resistance had increased within the B. fragilis group (from 14% in 1992 to 29% in 1996) and also among strains of clostridia (32%), P. acnes (18%) and Peptostreptococcus (28%). In the B. fragilis group multidrug resistance was unlikely to occur.

Is amoxicillin-cotrimoxazole the most appropriate antibiotic regimen for listeria meningoencephalitis? Review of 22 cases and the literature.

From June 1983 to January 1994, 22 adult patients with severe Listeria monocytogenes meningoencephalitis were observed in our Intensive Care Unit. Listeria monocytogenes was obtained in culture in cerebrospinal fluid or blood for every patient. Seven patients were treated with the combination ampicillin-aminoglycoside (group A) and 15 patients with the combination ampicillin (or amoxicillin)-cotrimoxazole (group A + C). Risk factors and gravity scores were similar in both groups. Failure of the 'gold standard' regimen (group A) was significantly higher (57%) compared to group A + C (6.7%) (P < 0.05). Mortality related to L. monocytogenes was 23.5% in group A compared to 6.7% in group A + C. Morbidity was reduced in group A + C (13.3%) compared to group A (60%) (P = 0.15). This unique study seems to demonstrate that amoxicillin-cotrimoxazole should be the most appropriate therapeutic regimen for Listeria meningoencephalitis.

Anti-Helicobacter pylori activity of Aristolochia paucinervis Pomel extracts.

The anti-Helicobacter pylori effect of the extracts and the fractions obtained from Aristolochia paucinervis rhizome and leaves were studied against a reference strain of H. pylori by using the agar dilution method. Only the methanol extracts and the hexane fractions of either the rhizome or the leaves exhibited an inhibitory activity at a concentration of < or =128 microg/ml. The leaf hexane fraction APLH demonstrated a higher inhibitory activity (MIC: 4 microg/ml) than the rhizome hexane fraction APRH (MIC: 16 microg/ml), the leaf methanol extract APLM (MIC: 32 microg/ml) and the rhizome methanol extract APRM (MIC: 128 microg/ml). This inhibitory activity was confirmed for the active extracts and fractions against clinical isolates of H. pylori (n = 20) for which MIC50) and MIC90 were determined.

Antibacterial activity of Aristolochia paucinervis Pomel.

Several fractions of the methanolic extract of the rhizome or the leaves of Aristolochia paucinervis Pomel were screened for antibacterial activity using the agar dilution method against fourteen reference bacterial strains. Only three fractions (defatted chloroformic rhizome fraction: APRC, rhizome ethyl acetate fraction: APRE and leaf chloroform fraction: APLC) showed an activity against at least one of the microorganisms tested. The minimum inhibitory concentration (MIC) determination showed that APRC was the most active against Clostridium perfringens, Clostridium difficile, Enterococcus faecalis, Micrococcus luteus and Bacillus subtilis. The high bacteriostatic activity of APRC was confirmed by its MIC determination against clinical strains of C. perfringens (n = 32), C. difficile (n = 31), and E. faecalis (n = 22). Results of this study suggest the potential interest of this highly active fraction and support the use of A. paucinervis Pomel in Moroccan traditional medicine to treat skin and soft-tissue infections, especially gas gangrene and intestinal diseases.

Bactericidal properties of the chloroform fraction from rhizomes of Aristolochia paucinervis Pomel.

The deffated chloroform fraction (APRC) obtained from the rhizomes of Aristolochia paucinervis Pomel (Aristolochiaceae) has a high bacteriostatic activity against bacterial strains like Clostridium perfringens ATCC 13124 and Enterococcus faecalis ATCC 29212. Here, we report the bactericidal activity of APRC against both strains which was evaluated by using time-to kill assays. The results showed that APRC produced an intense time-dependent bactericidal effect against C. perfringens, achieving over a 24 h-period a 5log10-unit decrease in CFU/ml at a concentration > or =1.25 x MIC. In contrast, when tested against E. faecalis, APRC exhibited a concentration-dependent killing activity at concentrations of 1.25 x MIC and 2.5 x MIC, yielding to a decrease of 1.5 and 2.5log10-unit in CFU/ml at 4 h, respectively. However, substantial regrowth of E. faecalis occurred within 24 h. Ultrastructural alterations were observed for both exposed microorganisms by scanning and transmission electron microscopy.

[Comparative study of four commercialized serologic methods for the diagnosis of gastric Helicobacter pylori infection]. / Etude comparative de quatre méthodes sérologiques commercialisées pour le diagnostic de l'infection gastrique à Helicobacter pylori.

OBJECTIVE: Four commercially available enzyme-linked immunosorbent assays (ELISA) were evaluated for serological diagnosis of Helicobacter pylori (H. pylori) infection in 79 untreated patients. METHODS: Infection has been diagnosed in 40 patients, in whom culture and/or urease test and histopathology from antral biopsies, were positive for H. pylori. RESULTS: Sensitivity (Se) and specificity (Sp) of these tests, calculated with indeterminate serological results (9 patients) classified as positive (ind +) or negative (ind -), were not statistically different: GAP-test (Bio-Rad), Se = 95% (ind +), 90% (ind -), Sp = 84.6% (ind +), 89.7% (ind -); Pylori-Stat (Biowhittaker), Se = 97.5% (ind + or -), Sp = 71.8% (ind +), 71.9% (ind -); Premier H. pylori (Biomedical Diagnostics), Se = 92.5% (ind +), 90% (ind -), Sp = 84.6% (ind +), 81.2% (ind -); Cobas-Core (Roche), Se = 92.5% (ind + or -), Sp = 76.9% (ind +), 79.5% (ind -). There was a strong correlation between mucosal inflammation and H. pylori status. Discrepancies between infectious status and at least one serology result were observed in 16 patients (11 H. pylori negative and 5 H. pylori positive patients). CONCLUSION: These 4 tests are of equivalent diagnostic value. Thus, the selection of one of them should take into account cost and practicability.

[Molecular typing by pulsed field gel electrophoresis of Enterobacter cloacae strains isolated from osteoarticular infections at the Nancy University Hospital 1990-1994]. / Typage moléculaire par électrophorèse en champ pulsé des souches d'Enterobacter cloacae isolées d'infections ostéo-articulaires au CHU de Nancy de 1990 à 1994.

Enterobacteriaceae represent more than 11% of bacteria involved in osteoarticular infections in adult and, among them, Enterobacter cloacae is found in 12% of the cases. The increased evolution of the antibiotic resistance rate of this species is worrying. However, all isolates responsible for this type of infection at the University Hospital of Nancy from 1990 to 1994 (24 strains isolated from 22 patients presented an identical antibiotype with especially a natural resistance phenotype to beta-lactam antibiotics except one cephalosporinase-over-producing strain. The DNA of these strains was studied by pulse-field gel electrophoresis after digestion by the restriction enzyme XbuI. The great genomic diversity obtained showed that the stability of the antibiotic susceptibility during the period studied was not due to the existence of unique clone but to that of multiple clones. The analysis of the restriction profiles has permitted to achieve a better differenciation of the strains than biotyping and antibiotyping, which confirms the high discrimination power of this genotypic method.

[The treatment of Helicobacter pylori infection]. / Le traitement de l'infection par Helicobacter pylori.

H. pylori causes inflammatory lesions of the stomach and duodenum. At the present time eradication is essentially recommended in case of gastric or duodenal ulcer. The choice of the appropriate drug depends on the characteristics of the H. pylori infection, the localization deep in the gastric mucosa, the physico-chemical properties of the gastric medium, especially the acidity which deactivates antibiotics, slow bacterial growth and the germ's sensitivity to antibiotics. Anti-infectious treatment is now based on a three-drug regimen combining an antisecretory drug (proton pump inhibitor or H2 receptor antagonist) and two antibiotics: clarithromycin associated with amoxicillin or an imidazol derivative (metronidazol or tinidazol) or tetracycline. Two antibiotics (clarithromycin, amoxicillin) as well as three anti-secretory agents (lansoprazole, omeprazole, ranitidine) have been authorized in France for three-drug regimens of 1 or 2 weeks leading to approximately 90% eradication. Special attention should be placed on the risk of resistance to antibiotics (macrolids and imidazol derivatives) and patient compliance required for successful eradication of H. pylori. Other therapeutic schemes are under assessment and a vaccine is being prepared. Eradication of H. pylori has totally changed the treatment of gastric and duodenal ulcers, eliminating the need for long-term treatment and avoiding complications.

How to improve the collection and analysis of hospital antibiotic consumption: preliminary results of the ConsoRes software experimental implementation.

OBJECTIVE: The online software ConsoRes is used to collect and analyze data on antibiotic consumption and evolution of bacterial resistance in healthcare institutions in every hospital ward (HW). We report the first results of ConsoRes implementation in the northeast hospitals of France. METHODOLOGY: ConsoRes was implemented in January 2011, in nine volunteer hospitals after performing an onsite assessment. Five of these hospitals were already monitoring antibiotic consumption with a network such as Raisin ATB or Antibiolor, providing feedback on the various evaluation tools. RESULTS: The ConsoRes data collection import function meets expectations of pharmacists, bacteriologists, or clinicians since it is user friendly, prevents redundant data input, and allows data transfer to the national databases. Importing the hospital organizational structure prevents mistakes on consumption allocation, which was noted in the previous databases, and makes comparison and benchmark analysis reliable. ConsoRes also provides a rapid consumption data feedback to all registered users within the hospital, whether in charge of a ward (clinician) or having a transversal function (pharmacist, bacteriologist). The availability of an automatic standard report or of an online customized report is another major feature of ConsoRes. CONCLUSION: Besides providing surveillance, the concomitant analysis of local antibiotic consumption and bacterial resistance should have an educational impact by allowing each user to implement actions within the framework of antibiotic stewardship.

Desulfovibrio spp. survive within KB cells and modulate inflammatory responses.

Desulfovibrio are sulfate-reducing anaerobic gram-negative rods that have been proposed as potential periodontopathogens. We investigated the capacity of Desulfovibrio to invade epithelial cells and induce cytokine secretion from these cells. Desulfovibrio strains were co-cultured with KB cells and counts of intracellular bacteria evaluated up to 3 days after infection. Desulfovibrio desulfuricans and Desulfovibrio fairfieldensis were able to survive within epithelial cells. Intracytoplasmic location of both bacterial species was confirmed by confocal laser scanning microscopy and transmission electron microscopy. Invasion was sensitive to nocodazole, an inhibitor of microtubule polymerization, but not to cytochalasin D, a microfilament inhibitor, suggesting that microtubule rearrangements were involved in the internalization of Desulfovibrio strains by KB cells. Infection by Desulfovibrio resulted in increased production of IL-6 and IL-8 by KB cells. The ability of D. desulfuricans and D. fairfieldensis to survive within oral epithelial cells and to modulate the epithelial immune response may contribute to the initiation and progression of periodontal diseases.

[Glycopeptide-resistant Enterococcus outbreak in an ICU with simultaneous circulation of two different clones]. / Epidémie en réanimation médicochirurgicale d'Enterococcus faecium résistants aux glycopeptides (ERG) avec cocirculation de deux clones différents.

AIM OF THE STUDY: To describe specific difficulties to control a glycopeptide-resistant Enterococcus (GRE) outbreak occurring in an intensive care unit (ICU) during a regional epidemy. PATIENTS AND METHODS: Following identification of a GRE clinical isolate in ICU, systematic screening was performed on admission and then weekly, by anal swabs. GRE carriers were isolated according to two processes: first (week [W] 2-W8), cohorting of carriers in a dedicated sector of the ICU, with dedicated HCW; this required closing four of the 16 ICU beds. Second (W8-W29), a specific unit was created outside the ICU. VanA-genotypes and pulsed-field gel electrophoresis (PFGE) profiles were analyzed. RESULTS: During the first outbreak period (102 rectal swabs), two patients were found colonized at admission: the index case transferred from Nancy hospital, carrier of the Nancy epidemy PFGE profile strain, and one patient from the haemodialysis unit, carrier of a GRE strain presenting a different PFGE profile called the Thionville strain. Seven patients were newly identified as GRE colonized (2 by the Nancy strain and 5 by the Thionville strain). Defective running of the ICU was noted. During the second period (442 samples), six ICU patients were found colonized, including four at admission. No other case was identified in 16 weeks. Outbreak extension to other hospital units was checked at W19. The Thionville strain was not found in other regional hospitals. CONCLUSION: ICUs concentrate GRE colonization risk. This study demonstrates interest of PFGE. These low virulence bacteria have few direct pathological consequences, but they cause organizational problems in ICUs.

Prevotella nanceiensis sp. nov., isolated from human clinical samples.

Three strains of anaerobic, non-pigmented, Gram-negative bacilli isolated from various human clinical samples were characterized in terms of phenotypic and genotypic tests, including sequence analysis of 16S rRNA and rpoB genes. The strains were most closely related to the type strains of Prevotella marshii and Prevotella shahii on the basis of both 16S rRNA (89.8 and 89.0 % identity, respectively) and rpoB gene sequences (83.1 and 82.8 % identity, respectively). Phylogenetic analysis showed that the isolates constituted a robust homogeneous group distinct from known species in the genus Prevotella. The rrn skeleton (as determined by PFGE) and the DNA G+C content, determined to be 39.4 mol% for strain LBN 293(T), distinguished the novel isolates from the type strains of P. marshii and P. shahii. The three strains were saccharolytic and produced acetic, lactic and succinic acids as major metabolic end products. Polyphasic investigations supported the proposal of a novel species, Prevotella nanceiensis sp. nov., with LBN 293(T) (=AIP 261.03(T) =CIP 108993(T) =CCUG 54409(T)) as the type strain.

Respiratory infections associated with nontuberculous mycobacteria in non-HIV patients.

The incidence of nontuberculous mycobacteria (NTM) pulmonary diseases in HIV-negative patients was studied prospectively from January 1, 2001 to December 31, 2003 by 32 sentinel sites distributed throughout France. In total, 262 patients who yielded NTM isolates from respiratory clinical specimens, met the bacteriological, radiological and clinical criteria established by the American Thoracic Society for NTM respiratory disease. Among the 262 NTM isolates, 234 were slow-growing mycobacteria (125 Mycobacterium avium-intracellulare complex (MAC), 66 M. xenopi, 34 M. kansasii) and 28 were rapidly growing mycobacteria (25 M. abscessus complex). In the Paris area, M. xenopi was the most frequently isolated species, followed by MAC. Most patients (>50%), except those with M. kansasii, had underlying predisposing factors such as pre-existing pulmonary disease or immune deficiency. Asthenia, weight loss, chronic cough and dyspnoea were the most common clinical symptoms. The classical radiological appearance of NTM infections was indistinguishable from that observed in patients with pulmonary tuberculosis. In summary, the incidence of nontuberculous mycobacteria pulmonary infections in HIV-negative patients was estimated at 0.74, 0.73 and 0.72 cases per 100,000 inhabitants in 2001, 2002 and 2003, respectively.