Effector Memory-Expressing CD45RA (TEMRA) CD8+ T Cells from Kidney Transplant Recipients Exhibit Enhanced Purinergic P2X4 Receptor-Dependent Proinflammatory and Migratory Responses

BACKGROUND

The mechanisms regulating CD8+ T cell migration to nonlymphoid tissue during inflammation have not been fully elucidated, and the migratory properties of effector memory CD8+ T cells that re-express CD45RA (TEMRA CD8+ T cells) remain unclear, despite their roles in autoimmune diseases and allotransplant rejection.

METHODS

We used single-cell proteomic profiling and functional testing of CD8+ T cell subsets to characterize their effector functions and migratory properties in healthy volunteers and kidney transplant recipients with stable or humoral rejection.

RESULTS

We showed that humoral rejection of a kidney allograft is associated with an accumulation of cytolytic TEMRA CD8+ T cells in blood and kidney graft biopsies. TEMRA CD8+ T cells from kidney transplant recipients exhibited enhanced migratory properties compared with effector memory (EM) CD8+ T cells, with enhanced adhesion to activated endothelium and transmigration in response to the chemokine CXCL12. CXCL12 directly triggers a purinergic P2×4 receptor-dependent proinflammatory response of TEMRA CD8+ T cells from transplant recipients. The stimulation with IL-15 promotes the CXCL12-induced migration of TEMRA and EM CD8+ T cells and promotes the generation of functional PSGL1, which interacts with the cell adhesion molecule P-selectin and adhesion of these cells to activated endothelium. Although disruption of the interaction between functional PSGL1 and P-selectin prevents the adhesion and transmigration of both TEMRA and EM CD8+ T cells, targeting VLA-4 or LFA-1 (integrins involved in T cell migration) specifically inhibited the migration of TEMRA CD8+ T cells from kidney transplant recipients.

CONCLUSIONS

Our findings highlight the active role of TEMRA CD8+ T cells in humoral transplant rejection and suggest that kidney transplant recipients may benefit from therapeutics targeting these cells.

Widespread implementation of EUCAST breakpoints for antibacterial susceptibility testing in Europe

The European Committee on Antimicrobial Susceptibility Testing (EUCAST) was established to harmonise clinical antimicrobial breakpoints and to define breakpoints for new agents in Europe. Data from the European Antimicrobial Resistance Surveillance Network (EARS-Net) external quality assessment (EQA) exercises from 2009 to 2012, from the United Kingdom External Quality Assessment Scheme (UK NEQAS) from November 2009 to March 2013 and data collected by EUCAST through a questionnaire in the first quarter of 2013 were analysed to investigate implementation of EUCAST guidelines in Europe. A rapid change to use of EUCAST breakpoints was observed over time. Figures for implementation of EUCAST breakpoints at the end of the studied period were 61.2% from EARS-Net data and 73.2% from UK NEQAS data. Responses to the EUCAST questionnaire indicated that EUCAST breakpoints were used by?over?50% of laboratories in 18 countries, by 10 to 50% of laboratories in eight countries and by?less than?10% in seven countries. The EUCAST disk diffusion method was used by more than 50% of laboratories in 12 countries, by 10 to 50% of laboratories in ten countries and by?less than?10% in eleven countries. EUCAST guidelines implementation is essential to ensure consistent clinical reporting of antimicrobial susceptibility results and antimicrobial resistance surveillance.

In VitroEvaluation of Faropenem Activity Against Anaerobic Bacteria

Faropenem, a new oral penem with broad spectrum activity, could be used as empirical treatment in infections due to unidentified anaerobes, but only a few investigations have been carried out on these bacteria. The aim of this study was to compare faropenem in vitro activity with that of positive antimicrobial controls (metronidazole, imipenem, meropenem, amoxicillin, amoxicillin-clavulanic acid, ticarcillin-clavulanic acid, cefotetan, cefoxitin and clindamycin) against 462 anaerobic bacterial strains. The reference agar dilution method was used according to the NCCLS standard. Faropenem demonstrated high antimicrobial activity, similar to that of both imipenem and meropenem (faropenem Minimal Inhibitory Concentrations 50% and 90% were 0.12 and 1 mg/L for all Gram-negative anaerobes, 0.25 and 1 mg/L for all Gram-positive anaerobes). Only 5 strains of the Bacteroides fragilis group (1.1% of all anaerobes) were resistant to faropenem, which compared favorably with that of other reference antianaerobic drugs. The results obtained confirm those previously reported.

MALDI-TOF MS Andromas strategy for the routine identification of bacteria, mycobacteria, yeasts, Aspergillus spp. and positive blood cultures

All organisms usually isolated in our laboratory are now routinely identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) using the Andromas software. The aim of this study was to describe the use of this strategy in a routine clinical microbiology laboratory. The microorganisms identified included bacteria, mycobacteria, yeasts and Aspergillus spp. isolated on solid media or extracted directly from blood cultures. MALDI-TOF MS was performed on 2665 bacteria isolated on solid media, corresponding to all bacteria isolated during this period except Escherichia coli grown on chromogenic media. All acquisitions were performed without extraction. After a single acquisition, 93.1% of bacteria grown on solid media were correctly identified. When the first acquisition was not contributory, a second acquisition was performed either the same day or the next day. After two acquisitions, the rate of bacteria identified increased to 99.2%. The failures reported on 21 strains were due to an unknown profile attributed to new species (9) or an insufficient quality of the spectrum (12). MALDI-TOF MS has been applied to 162 positive blood cultures. The identification rate was 91.4%. All mycobacteria isolated during this period (22) were correctly identified by MALDI-TOF MS without any extraction. For 96.3% and 92.2% of yeasts and Aspergillus spp., respectively, the identification was obtained with a single acquisition. After a second acquisition, the overall identification rate was 98.8% for yeasts (160/162) and 98.4% (63/64) for Aspergillus spp. In conclusion, the MALDI-TOF MS strategy used in this work allows a rapid and efficient identification of all microorganisms isolated routinely.

[Activity of doripenem against anaerobic bacteria]

AIMS OF THE STUDY

This study examines the activity of doripenem, a new carbapenem compound compared with amoxicillin-clavulanic acid, piperacillin+tazobactam, imipenem, clindamycin and metronidazole against 316 anaerobes.

METHODS

Inoculum preparation and agar dilution method were performed according to the CLSI method for anaerobes (M11A7).

RESULTS

At a concentration of 4μg/ml doripenem and imipenem (IMP) inhibited 122 (96 %) and 126 (99 %) strains of the Bacteroides fragilis group, respectively. In contrast, doripenem appeared more potent than IMP against Gram-positive anaerobes inhibiting at the same concentration of 4μg/ml 145/145 strains (100 %) versus 115/145 for IMP (79.3 %). Against 316 anaerobic strains, the carbapenem doripenem had an MIC(50) of 0.25μg/ml and an MIC(90) of 2μg/ml. Results were similar to those for imipenem (MIC(50) of 0.125μg/ml and MIC(90) of 4μg/ml). If we consider the resistant breakpoints of the two carbapenems as defined by EUCAST, the resistance rate for doripenem (MIC>4μg/ml) 1.6 % is similar to that of imipenem (MIC>8μg/ml) 1.3 %.

CONCLUSION

Thus independently of the PK/PD parameters the two carbapenems demonstrated very close activity; doripenem was more potent on Gram-positive anaerobes and slightly less potent against Gram-negative anaerobes mainly the B. fragilis group. Further clinical studies are needed to assess its usefulness in patients.

Anaerobic bacteria and antibiotics: What kind of unexpected resistance could I find in my laboratory tomorrow?

The purpose of this article is to set out some important considerations on the main emerging antibiotic resistance patterns among anaerobic bacteria. The first point concerns the Bacteroides fragilis group and its resistance to the combination of β-lactam+β-lactamase inhibitor. When there is overproduction of cephalosporinase, it results in increased resistance to the β-lactams while maintaining susceptibility to β-lactams/β-lactamase inhibitor combinations. However, if another resistance mechanism is added, such as a loss of porin, resistances to β-lactam+β-lactamase inhibitor combinations may occur. The second point is resistance to metronidazole occurring due to nim genes. PCR detection of nim genes alone is not sufficient for predicting resistance to metronidazole; actual MIC determinations are required. Therefore, it can be assumed that other resistance mechanisms can also be involved. Although metronidazole resistance remains rare for the B. fragilis group, it has nevertheless been detected worldwide and also been observed spreading to other species. In some cases where there is only a decreased susceptibility, clinical failures may occur. The last point concerns resistance of Clostridium species to glycopeptides and lipopeptides. Low levels of resistance have been detected with these antibiotics. Van genes have been detected not only in clostridia but also in other species. In conclusion, antibiotic resistance involves different mechanisms and affects many anaerobic species and is spreading worldwide. This demonstrates the need to continue with antibiotic resistance testing and surveys in anaerobic bacteria.

In vitro activity of secnidazole against Atopobium vaginae, an anaerobic pathogen involved in bacterial vaginosis

Bacterial vaginosis is a polymicrobial syndrome. The most important marker for bacterial vaginosis is the presence of Gardnerella vaginalis and Atopobium vaginae. In this study, the in vitro susceptibilities to metronidazole and secnidazole of 16 strains of A. vaginae were tested with the agar dilution method. We observed an MIC range for metronidazole of 4-64 mg/L (MIC(50), 8 mg/L; MIC(90), 32 mg/L) and an MIC range for secnidazole of 4-128 mg/L (MIC(50), 16 mg/L; MIC(90), 64 mg/L). According to these findings, we can conclude that the activity of secnidazole is similar to that of metronidazole.

[Pneumonia in a traveller coming back from Asia]

A case of Salmonella paratyphi A infection was diagnosed late in a patient treated for febrile pneumonia after his returning from India. This case was remarkable in two aspects: first, it illustrated the reemergence of S.paratyphi A infections in people having traveled to India, with increasing fluoroquinolone resistance, and second the difficulty of diagnosing this disease, since the patient was initially treated for pneumonia and flu-like syndrome. Salmonella typhi or paratyphi infections should be evoked in case of persistent fever in patients having traveled to endemic areas, even if digestive signs are absent. Furthermore, choosing an empiric antibiotic treatment with fluoroquinolones could lead to treatment failure if the patient traveled in a country where fluoroquinolone resistance is high, as in Asia and especially in India.

[Evaluation of the in vitro activity of two betalactams on the oxidative metabolism of polymorphonuclear neutrophils]

STUDY AIMS

The aim was to evaluate the in vitro effects of amoxicillin and its combination with clavulanic acid, two beta-lactams intravenously injected, on the oxidative metabolism of polymorphonuclear neutrophils. These cells play the major role in the "respiratory burst" as they produce superoxide anion to kill the infectious agent. An activation of this process by the injected antibiotics could enhance the bactericidal action or explain some of adverse effects.

MATERIALS AND METHODS

Two models were used to estimate the O(2)(-) amounts produced in the presence of the antimicrobial agents. In the cellular model, O(2)(-) was generated by neutrophils artificially stimulated or not (separated by a gradient centrifugation through Histopaque 1077). In the acellular model, O(2)(-) was produced by the xanthine-xanthine oxidase system. O(2)(-) was measured by spectrophotometry using the ferricytochrome C reduction.

RESULTS

The O(2)(-) production by polymorphonuclear neutrophils was increased when both antibiotics were added to the reaction mixture. A significant activation of the cell oxidative metabolism was observed with amoxicillin using various stimulating agents, that was higher without stimulation and lower when amoxicillin and clavulanic acid were associated.

CONCLUSION

Amoxicillin could either activate polymorphonuclear neutrophils NADPH-oxidase or cause its activation by a membrane effect, or interfere with the zymosan activation way. It could then be supposed that this antimicrobial agent intensified the bactericidal effects.

Antibiotic resistance among anaerobic Gram-negative bacilli: lessons from a French multicentric survey

Temporal changes of antibiotic susceptibilities among anaerobes in France are followed in our laboratory since 1992. For Bacteroides strains, resistance increased from 1992 to 1998 for amoxicillin-clavulanic acid, cefotetan and clindamycin. The present study evaluates the situation in 2000 for 434 Gram-negative anaerobic clinical isolates (obtained from 9 large university hospitals) by testing amoxicillin and ticarcillin alone or combined with clavulanic acid, cefoxitin, cefotetan, imipenem, clindamycin and metronidazole (using the NCCLS-approved method for MIC determination. The main genera tested included Bacteroides (359 strains of the fragilis group), Prevotella (40 strains), Fusobacterium (23 strains) and miscellaneous species (8 strains). Resistance rates within the B. fragilis group were: amoxicillin-clavulanic acid 5.6%, ticarcillin 33%, ticarcillin-clavulanic acid 2%, cefoxitin 13%, cefotetan 44%, clindamycin 33%, imipenem 1% and metronidazole <1%, respectively. Only one strain of B. fragilis was resistant to metronidazole (MIC=64 mg/L); due to the presence of the nimA gene on the chromosome. Resistance to imipenem or metronidazole was only found among the B. fragilis species. These two former drugs excepted, B. fragilis was less resistant to antibiotics than the other species. beta-lactamase production was detected for 357/359 strains of the fragilis group, 26/40 stains of Prevotella and 3/23 strains of Fusobacterium. Dynamic changes of antibacterial resistance are occurring within the B. fragilis group: decreased resistance to amoxicillin-clavulanic acid, ticarcillin-clavulanic acid, imipenem while resistance for cefoxitin, cefotetan, clindamycin continues to increase. Regular antibiotic surveys are needed as a source of information to guide the empirical therapy of anaerobic infections.

In vitro activity against anaerobes of retapamulin, a new topical antibiotic for treatment of skin infections

OBJECTIVES

Retapamulin is the first agent of the pleuromutilin class formulated as a topical antibacterial for treating skin infections. The aim of this study was to determine the antimicrobial activity of retapamulin by determining the minimal inhibitory concentration (MIC) values of this new drug and comparators against a wide range of anaerobic bacteria of human origin.

METHODS

The in vitro activity of retapamulin and six comparators (amoxicillin, amoxicillin/clavulanic acid, ceftriaxone, imipenem, clindamycin and metronidazole) was evaluated against 232 anaerobic clinical isolates. MICs were determined by the CLSI reference agar dilution method (M11-A6).

RESULTS

Ceftriaxone, clindamycin and amoxicillin/clavulanic acid resistance rates were 54%, 42% and 9.6%, respectively, within the Bacteroides fragilis group. Despite high resistance rates to various antibiotics, retapamulin inhibited 37/52 (71%) strains of the B. fragilis group and 85/87 (98%) of the other Gram-negative bacilli at a concentration of 2 mg/L or less. All the investigated strains of Clostridium perfringens were inhibited by 1 mg/L retapamulin. Three strains of C. difficile and one strain of C. clostridioforme demonstrated decreased susceptibility to retapamulin. Based on inhibitory concentrations, retapamulin was more active than clindamycin, metronidazole and ceftriaxone against Propionibacterium acnes and anaerobic Gram-positive cocci, as all isolates were inhibited by <or=2 mg/L.

CONCLUSIONS

At <or=2 mg/L, retapamulin inhibited 90% of all 232 anaerobes tested, whereas overall resistance rates for the comparators were as follows: co-amoxiclav, 2%; metronidazole, 12%; clindamycin, 15% and ceftriaxone, 20%. The broad anaerobic spectrum demonstrated by retapamulin in vitro is attractive. Pending further clinical investigation, retapamulin may offer an alternative treatment for anaerobic skin infections in this era of increasing resistance.

Evaluation of the in vitro activity of ertapenem and nine other comparator agents against 337 anaerobic bacteria

Ertapenem activity in vitro was compared with that of nine reference antibiotics against 337 anaerobes by determining minimal inhibition concentrations (MICs). Amongst 246 Gram-negative anaerobes, 4, 8, 3, 4, 7, 2 and 52 strains showed resistance to ertapenem, amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoxitin, imipenem and clindamycin, respectively, and all strains were inhibited by metronidazole. Ertapenem MIC(50) values were 0.5, 0.25, 0.06 and <or=0.03mg/L for the Bacteroides fragilis group, Prevotella spp., fusobacteria and Gram-positive cocci, respectively. Overall resistance rates were 2.1%, 51.3%, 2.4%, 1.2%, 1.5%, 7.1%, 0.6%, 22% and 1.5% for ertapenem, amoxicillin, amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoxitin, imipenem, clindamycin and metronidazole, respectively. Ertapenem showed a broad spectrum and good activity against anaerobes.

[Community-acquired acute maxillary sinusitis or rhinosinusitis in adults in France: current management]

Sinus infections, often viral, are a common reason for physician visits. The multiplicity of clinical presentations makes its diagnosis difficult. The problem is to recognize bacterial infection without additional testing, except in cases of treatment failures, complications or relapse. Patients with signs suggestive of rhinosinusitis fall into one of four basic clinical situations: common colds, 'doubtful' rhinosinusitis, apparent acute maxillary bacterial rhinosinusitis, and complications. Anterior rhinoscopy may help confirm diagnosis. Current bacterial epidemiology is based on the results of clinical studies, microbial ecology, and samples taken in cases of treatment failure. The two bacteria isolated most frequently are Streptococcus pneumoniae and Haemophilus influenzae, both of which pose resistance problems. Moraxella catarrhalis, Streptococcus pyogenes and Staphylococcus aureus are isolated less often. The dominant issue in management of acute rhinosinusitis is whether to use antibiotic or symptomatic treatment. For viral infections, antibiotic therapy is useless and highly inadvisable. For 'doubtful' infections, symptomatic treatment is likely to lead to recovery. The use of non-recommended antibiotics also increases the risk of selection of resistant bacteria. When bacterial rhinosinusitis is strongly suspected, recourse to antibiotic treatment is recommended in view of the benefits in this situation (AFSSAPS 2005). This treatment is probabilistic, should be decided at the end of the consultation, and follows the AFSSAPS guidelines.

Hospital-Acquired Pneumonia in Critically Ill Patients: Factors Associated with Episodes Due to Imipenem-Resistant Organisms

BACKGROUND

Inadequate initial antimicrobial therapy represents one of the factors associated with mortality of patients suffering from hospital-acquired pneumonia. According to its wide antimicrobial spectrum, imipenem belongs to the usual antibiotics proposed by current guidelines for such a therapy. However, major changes in the antibiotic susceptibility patterns of bacteria in the intensive care unit (ICU) have occurred. Our goal was to determine the incidence of hospital-acquired pneumonia (HAP) due to imipenem-resistant organism(s) in our ICU and to identify factors associated with such a resistance.

PATIENTS AND METHODS

From January 1994 to December 2001, all consecutive patients admitted to our ICU for HAP or exhibiting HAP during their ICU stay were included in an observational cohort. Patients with a bacteriologically documented HAP were studied. For each causative pathogen, imipenem susceptibility was routinely determined. Patients with an HAP episode due to at least one imipenem-resistant causative organism were compared with patients who developed HAP in which all incriminated pathogens were imipenem susceptible.

RESULTS

235 patients were included in our observational cohort. Among them, 168 had an HAP episode with a bacteriologically proven infection. In 42 patients (25%), at least one causative organism was resistant to imipenem. The 44 imipenem-resistant organisms were Staphylococcus aureus (n = 15), Pseudomonas aeruginosa (n = 14), Stenotrophomonas maltophilia (n = 13), and Acinetobacter baumannii (n = 2). Multivariate analysis identified four significant independent factors associated with resistance of causative organism(s) to imipenem: prior use of a fluoroquinolone (AOR = 3.9; 95% CI: 1.8 to 8.8; p < 0.0001), prior use of an aminoglycoside (AOR = 2.6; CI: 1.2 to 5.9; p = 0.02), use of invasive blood pressure monitoring (AOR = 2.7; CI: 1.0 to 7.0; p = 0.04) and bilateral chest X-ray involvement (AOR = 2.6; CI: 1.1 to 5.8; p = 0.02).

CONCLUSION

Factors associated with potential inadequacy of imipenem used as the single antibiotic for initial empiric treatment for HAP were identified. When they are present, imipenem should be either combined with antibiotics such as vancomycin and ciprofloxacin or replaced with another broad-spectrum antimicrobial regimen.

A Bacteroides thetaiotamicron porin that could take part in resistance to beta-lactams

The aim of this study was to investigate porin absence or deficiency in two Bacteroides thetaiotaomicron strains resistant to amoxicillin combined with clavulanic acid. Their outer membrane protein (OMP) extracts and those of two susceptible strains were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and compared to detect differences between the strains. A protein band of interest at around 70 kDa electro-eluted for each strain, was tested in a liposome swelling assay. A decrease in initial absorbency was noted for the two susceptible strains but not for the two resistant strains. The liposome swelling of the two susceptible strains was directly visualized by photon microscopy and then photographed. This suggested a B. thetaiotaomicron porin of around 70 kDa could take part in resistance to beta-lactams.

In vitro activities of a new des-fluoro(6) quinolone, garenoxacin, against clinical anaerobic bacteria

The antimicrobial activities of garenoxacin and eight other antibiotics against 641 anaerobic isolates were evaluated with the NCCLS agar dilution method. Overall, the MICs of garenoxacin for 50 and 90% of the strains tested (in micrograms per milliliter) were as follows: Bacteroides fragilis group, 0.5 and 2; Prevotella spp., 0.25 and 2; Fusobacterium spp., 0.25 and 0.5; Porphyromonas spp., 0.125 and 0.25; Bilophila wadsworthia, 0.5 and 1; Veillonella spp., 0.25 and 0.5; Clostridium spp., 0.25 and 1; Clostridium difficile, 2 and >64; Bifidobacterium spp., 1 and 2; Eggerthella lenta, 0.25 and 1; Propionibacterium spp., 0.5 and 0.5; gram-positive cocci, 0.125 and 0.25.

In vitro activity of gatifloxacin, a new fluoroquinolone, against 204 anaerobes compared to seven other compounds

The activity of gatifloxacin, a new fluoroquinolone derivative, was compared with the activities of ciprofloxacin, levofloxacin, amoxicillin, amoxicillin-clavulanate, imipenem, clindamycin and metronidazole against 204 anaerobes isolated from clinical specimens, by MIC determination, using the reference agar dilution method. When determining the overall activity against anaerobes, the MIC50/90 (mg/L) values were amoxicillin 16/>64, amoxicillin-clavulanate 0.125/1, imipenem 0.25/0.5, clindamycin 0.5/>256, metronidazole 1/8, ciprofloxacin 2/32, levofloxacin 1/8 and gatifloxacin 0.5/4. The broad in vitro spectrum of gatifloxacin is promising for the treatment of mixed anaerobic infections, especially those of the respiratory tract, ear, sinus, skin and soft tissues, and bite wounds. These data suggest that gatifloxacin may have a clinical role in the treatment of infections in which anaerobic pathogens are involved.

Beta-lactamase production in Prevotella and in vitro susceptibilities to selected beta-lactam antibiotics [corrected]

This study looked for beta-lactamase production in 100 Prevotella isolates. MICs were determined for amoxycillin, ticarcillin, amoxycillin+clavulanate, cephalothin, cefuroxime, cefixime, cefpodoxime and cefotaxime using the reference agar dilution method (standard M11 A4, NCCLS). Beta-lactamase activity was detected in 58 of the 100 isolates, 24 of 46 black-pigmented Provotella and 34 of 54 non-pigmented Prevotella. All beta-lactamase-negative strains were susceptible to all beta-lactam antibiotics with the exception of cefuroxime and cefixime. Overall, resistance rates of Prevotella strains were lower for ticarcillin (8%) and celefotaxime (12%) than for the other cephalosporins. All Prevotella isolates were susceptible to amoxycillin and were all inhibited by 2 mg/l or less amoxycillin [corrected].

[Are the principles of treatment of chronic osteitis applicable to the diabetic foot?]

OBJECTIVE

The interest of the management of bone infections in the diabetic foot, inspired by the recommendations for the treatment of chronic osteitis, was assessed in this study.

METHODS

Twenty bone infections in 17 diabetic patients with moderate to mild infections of the feet were confirmed by the results of X-ray and/or scintigraphic studies and bone surgery biopsy cultures revealing one or more bacteria sensitive to standard osteitis treatment (rifampicine + fluoroquinolone). The patients had received this treatment per os for a median duration of 6 months (3 to 10 months). Clinical follow-up was carried out during a consultation at 1, 3 and 6 months during treatment and then by telephone every six months after the end of treatment. Clinical success was defined as the disappearance of any local sign of infection and by the absence of relapse during the post-treatment follow-up period. The evolution of the bone infection was also assessed by the results of a control conducted 3 to 6 months after initiation of the antibiotic treatment.

RESULTS

At the end of the treatment, all signs of infection had disappeared in 15/17 patients (88.2%) and no relapse had occurred in 14 (82.3%) patients at the end of a median post-treatment period of 22 months (12 to 41 months). Resection of necrotic bone was performed at the same time as the bone biopsy in 2 patients. The median duration of hospitalisation was of 14 days (3 to 53 days). During the study, a multi-resistant germ was isolated in 4 patients (1 Pseudomonas aeruginosa, 3 Staphylococcus aureus). During the post-treatment follow-up, 3 patients dies from causes unrelated to the infection treated. No serious adverse event was reported during the study.

DISCUSSION

The results of this pilot study support the rationale of applying the treatment regimens of chronic osteitis to diabetic lesions of the feet, but are only applicable to comparable patients presenting with non-severe lesions of the feet. Moreover, the use of antibiotics with potent selection of resistance such as rifampicine and fluoroquinolone, requires that bone biopsies be taken, which is not easy in all the diabetic foot care centres. We are presently conducting a study to identify the sub-populations of diabetic patients who could benefit from such treatment.

Rifampicin-ofloxacin oral regimen for the treatment of mild to moderate diabetic foot osteomyelitis

Seventeen diabetic patients with moderate to mild foot lesions associated with 20 osteomyelitic bones diagnosed by both bone scan and bone biopsy received rifampicin plus ofloxacin for a median duration of 6 months. Cure was defined as disappearance of all signs and symptoms of infection at the end of the treatment and absence of relapse during follow up. At the end of the treatment period, cure was achieved in 15 patients (88.2%) and was maintained in 13 patients (76.5%) at the end of an average post-treatment follow-up of 22 months. No serious drug-related adverse events were recorded.

[Availability of antiretroviral agents in the city: a 1-year assessment in the Lille metropolitan area]

OBJECTIVES

Dispensing antiretroviral drugs in private pharmacies has been allowed in France since October 1997. One year after this measure was implemented, we conducted a survey of patients and pharmacists in the Lille metropolitan area to assess its impact.

METHOD

Structured interviews with a representative sample of private pharmacists and HIV infected patients in the Lille metropolitan area were carried out.

RESULTS

100 pharmacists were interviewed. Most worked in urban areas and their main clientele were from the neighbourhood. Most felt that HIV infection was a common disease and were interested in dispensing antiretroviral drugs as a public health service despite the marginal income from these sales. Two-thirds had received training on HIV infection and most knew the importance of adhering to the treatment. However, the number of antiretroviral drugs and the classes of these drugs that were available were not well known. Among the 97 patients followed by the Service of Infectious Diseases of the Tourcoing Hospital, 22% received their medications from the local private pharmacy, 62% got them from the hospital pharmacy and 16% got them from both places. However, 39% received at least one drug that was only available from the hospital pharmacy. The patients going to private pharmacies described an improved quality of life and mostly chose their regular pharmacist to get their medications. Most preferred to get their medications openly, as opposed to secretly. Many patients going to the hospital pharmacy made their choice based on better confidentiality. Private pharmacists also expressed the fear of lack of confidentiality. Private pharmacies were seen as friendlier with quicker service, but slightly less competent than the hospital pharmacy. Finally, the topic of adhering to this form of HIV treatment is rarely discussed in private pharmacies.

CONCLUSIONS

Both the patients and private pharmacists appreciate the fact that these drugs can be dispensed in private pharmacies, but the impact of this measure is limited by the number of drugs that are only available at the hospital pharmacy. Private pharmacists do not often discuss the importance of adhering to the therapy and progress is needed in this area.

Search for enterotoxin gene in Bacteroides fragilis strains isolated from clinical specimens in Poland, Great Britain, The Netherlands and France

BACKGROUND

Bacteroides fragilis is a member of normal human flora and well known pathogenic agent. This bacterium produces many virulence factors. In 1984 new virulence factor--enterotoxin was described. The aim of the study was to search for enterotoxin gene in B. fragilis strains isolated from clinical specimens.

MATERIAL AND METHODS

Strains isolated in Poland, Great Britain, France and the Netherlands were cultured on BBE medium. For DNA isolation Genomic DNA PREP PLUS isolation kit manufactured by A&A Biotechnology (Poland) was used. In order to detect enterotoxin (fragilysin) gene, polymerase chain reaction (PCR) was applied utilizing the following primers: 404 (GAG CGG AAG ACG GTG TAT GTG ATT TGT) and 407 (TGC TCA GCG CCC AGT ATA TGA CCT AGT). DNA obtained from bacterial cells was amplified in thermocycler Techne. The amplification products were detected by the electrophoresis in 1% agarose gel.

RESULTS

Among 65 investigated B. fragilis strains, the enterotoxin gene was detected in DNA isolated from 12 strains.

CONCLUSION

The enterotoxin producing B. fragilis strains were detected among strains isolated from different clinical specimens in Poland, Great Britain, the Netherlands and France.

[Beta-lactamase production in Prevotella and in vitro sensitivity to beta-lactamines]

FREQUENCY OF BETA-LACTAMASE ACTIVITY: Prevotella spp. are anaerobic pathogenic bacteria. Among 100 strains isolated, beta-lactamase producing strains accounted for 58%. Fifty-two percent of the strains were pigmented and 63% were non pigmented. ACTIVITY AGAINST BETA-LACTAMASE PRODUCERS: In general, all the antibiotics exhibited higher activity against non producers than against beta-lactamase producers. Minimum inhibitory concentrations for amoxicillin/davulanic acid was lower or equal to 2 mg/l for all strains isolated.

Roles of gyrA mutations in resistance of clinical isolates and in vitro mutants of Bacteroides fragilis to the new fluoroquinolone trovafloxacin

We determined whether gyrA mutations were present in fluoroquinolone-resistant laboratory mutants derived from the Bacteroides fragilis reference strain ATCC 25285 and in clinical isolates of B. fragilis. The two first-step mutants selected on ciprofloxacin (CIP) were devoid of gyrA mutations, whereas two of the three CIP-selected second-step mutants studied presented the same gyrA mutation leading to a Ser82Phe change. Unusual GyrA alterations, Asp81Asn or Ala118Val, were detected in two of the three first-step mutants selected on trovafloxacin (TRO), Mt3 and Mt1, respectively. The Ala118Val change had no effect on the susceptibility of Mt1 to CIP. No second-step mutant could be obtained with TRO as a selector. For the 12 clinical isolates studied, a Ser82Phe change in GyrA was found only in the 3 strains which showed the highest levels of TRO resistance (MIC, 4 microgram/ml). Thus, the resistance phenotypes and genotypes observed in fluoroquinolone-resistant clinical isolates of B. fragilis were similar to those found in CIP-selected laboratory mutants, whereas peculiar mutational events could be selected in vitro with TRO.

Isolation and antibacterial activity of phenylpropanoid derivatives from Ballota nigra

In addition to the previously isolated phenylpropanoid glycosides verbascoside 1, forsythoside B 2, arenarioside 3 and ballotetroside 4, another four compounds were isolated from generative aerial parts of Ballota nigra: three phenylpropanoid glycosides, alyssonoside 5, lavandulifolioside 6 and angoroside A 7 and a non-glycosidic derivative (+)-(E)-caffeoyl-L-malic acid 8. The antibacterial activity of the five major compounds (1-4 and 8) was tested against gram-positive and gram-negative bacteria. Three of them (1-3) exhibited a moderate antimicrobial activity against Proteus mirabilis and Staphylococcus aureus including one methicillin-resistant strain.

Susceptibility testing of anaerobic bacteria: evaluation of the redesigned (Version 96) bioMérieux ATB ANA device

We compared the susceptibility results for 200 clinical anaerobes with nine antibiotics obtained by using a new ATB ANA (bioMérieux) device against those obtained by the National Committee for Clinical Laboratory Standards (NCCLS) standard agar dilution method. For better evaluation of the device, we added some resistant Bacteroides fragilis group strains from our own collection: 3, 6, and 12 strains that were resistant to imipenem, ticarcillin plus clavulanic acid, and co-amoxiclav, respectively, and 2 other strains with decreased susceptibility to metronidazole. For some strains that did not grow on ATB S medium, tests were performed by using West-Wilkins medium supplemented with 1.5% agar. The new ATB ANA device made clinical categorization of the investigated strains possible, according to French (Committee of the Antibiogram of the French Society of Microbiology) or U.S. (NCCLS) breakpoints, with the following respective results: category agreement, 94.3 and 94.9%; minor errors, 4.8 and 3.8%; major errors, 0.4 and 0.8%; and very major errors 4.6 and 4.2%. The ATB ANA device was able to detect low-level metronidazole-resistant B. fragilis strains according to the French breakpoints but not the NCCLS ones. For B. fragilis and beta-lactamase-positive Prevotella strains, the clustering effect of amoxicillin MICs around the French breakpoints led to more frequent minor errors. ATB ANA is a very convenient method to determine the antibiotic susceptibilities of anaerobes. Results obtained by ATB ANA correlated well with those obtained by the reference method.