The Antibacterial Activity of Tramadol Against Bacteria Associated with Infectious Complications After Local or Regional Anesthesia

BACKGROUND

Tramadol is a synthetic analog of codeine with opioid and local anesthetic properties. It is used as a central-acting analgesic, and recently, in subcutaneous or intradermal injections, as a local anesthetic. We investigated in vitro the antibacterial activity of tramadol in the absence of any local anesthetics against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa pathogens that can cause infectious complications after local or regional anesthesia.

METHODS

Bacterial cultures were grown for 18 h, diluted in sterile physiological saline, and incubated for 6 or 24 h at 37 degrees C with 6.25, 12.5, or 25 mg/mL tramadol. The mixtures were then plated onto blood agar and colony counts were recorded after 24 h incubation at 37 degrees C.

RESULTS

Tramadol had bactericidal activity against E. coli and S. epidermidis compared with controls: at 25 mg/mL for 6 h or at 12.5 mg/mL for 24 h, tramadol decreased by approximately 7 log(10) (P < 0.001) the colony counts of E. coli (100% kill). Similar results were obtained with S. epidermidis, with approximately 6 log(10) reduction (100% kill) when tramadol was used at 25 mg/mL for 24 h (P < 0.001). The antibacterial effect of 25 mg/mL tramadol was lower against S. aureus and P. aeruginosa, reducing the growth of these strains by approximately 3log(10) after 24 h (P < 0.001).

CONCLUSIONS

Tramadol has dose- and time-dependent bactericidal activity against E. coli and S. epidermidis, as well as antibacterial activity against S. aureus and P. aeruginosa. The antibacterial properties of tramadol may be useful for reducing the risk of bacterial infection after local or regional anesthesia.

Antimicrobial treatment of Capnocytophaga infections

Capnocytophaga spp. are normal inhabitants of the oropharyngeal flora. They are also involved in periodontal diseases or animal bites, complicated by septicaemia with dissemination to a great variety of sites, both in immunocompetent and immunocompromised hosts. This review will focus on their pathogenesis, spectrum of clinical infections and susceptibility to disinfectants and antibiotics. The spread of beta-lactamase-producing strains limits the use of beta-lactams as first-line treatments, underlying the necessity to test the in vitro susceptibility of clinical strains. Many antimicrobial treatments have been used, despite an absence of randomised studies and guidelines regarding the duration of treatment according to infected sites. Imipenem/cilastatin, clindamycin or beta-lactamase inhibitor combinations are always effective and their use can be recommended in all infections.

Virulence of viable but nonculturable S. Typhimurium LT2 after peracetic acid treatment

S. Typhimurium LT2 cells suspended in sterilized sewage effluent water (SEW) and in distilled water microcosms were exposed to 0, 7, 15 and 20 mg/l peracetic acid, and tested for viability and virulence. After treatment for one hour, colony forming units decreased by at least 5 log units at peracetic acid concentration of 7 mg/l. In SEW, at peracetic acid concentration of 15 mg/l, the cells were nonculturable (VNC), but retained virulence as demonstrated by invasion assays of HeLa cells. Higher concentrations (greater than or equal to 20 mg/l) resulted in bacterial death, i.e. substrate non-responsive cells. Despite morphological alterations of the bacteria after peracetic acid treatment, visualized by transmission electronic microscopy, conservation of both adhesive and invasive capacities was confirmed by scanning electron microscopy after exposure to 0-15 mg/l peracetic acid. Public health professionals need to recognize that peracetic acid-treated Salmonella is capable of modifying its physiological characteristics, including entering and recovering from the viable but nonculturable state, and may remain virulent after a stay in SEW followed by peracetic acid treatment.

Capnocytophaga in the dental plaque of immunocompromised children with cancer

OBJECTIVES

(i) To compare the prevalence and levels of Capnocytophaga, a known systemic pathogen in immunocompromised patients, in the dental plaque of healthy children and children with cancer, and (ii) to determine the susceptibility of strains isolated from cancer patients to a range of antibiotics.

PATIENTS AND METHODS

Thirty-one children with cancer undergoing a first course of immunosuppressive chemotherapy and 30 healthy control children were included in the study. Samples were collected on days 0, 7, 14, and 21 of the cure (and equivalent dates in controls). Susceptibility to antibiotics was tested using an agar dilution method and galleries with predefined concentrations of selected antibiotics.

RESULTS

There was a significant drop in the total anaerobic cultivable flora on day 14 and in the prevalence of Capnocytophaga on days 14 and 21 in the children with cancer. The proportion of Capnocytophaga in the anaerobic flora, however, was high in certain cancer patients. Beta-lactam/beta-lactamase inhibitor combinations, imipenem, clindamycin, and tetracycline were the most effective against Capnocytophaga.

CONCLUSION

This study showed that Capnocytophaga decreased in prevalence and proportion in the dental plaque of cancer patients during chemotherapy but became predominant in some cases. It is recommended that imipenem or beta-lactam/beta-lactamase inhibitor combinations be used to treat Capnocytophaga bacteraemia.

Peracetic acid stress-induced genetic rearrangements in Escherichia coli H10407 detected by RAPD and RFLP analyses

The discriminatory powers of random amplified polymorphic DNA (RAPD) analysis and restriction fragment length polymorphism (RFLP) were assessed for the detection and comparison of DNA modifications caused by an oxidative stress. DNA extracted from peracetic acid (PAA)-treated Escherichia coli H10407 was randomly amplified with the 10-mer primer OPZ14, which generated one stress-induced fragment. RFLP and RAPD profiles were hybridized by Southern blotting with the digoxigenin-labelled RAPD product. Untreated and PAA-treated cells had difference band profiles. The results indicate that RAPD analysis could be used as a discriminatory tool for investigating genetic rearrangements in E. coli caused by oxidative stress and that RFLP analysis could be used to confirm the rearrangements.

Tenosynovitis of the wrist due to resistant Mycobacterium tuberculosis in a heart transplant patient

Tubercular tenosynovitis is now rare, which can delay diagnosis of this disease. We report a case of tenosynovitis of the wrist in a heart transplant patient caused by an isoniazid- and streptomycin-resistant Mycobacterium tuberculosis strain. Despite immunosuppression therapy, which can lead to a smoldering evolution, molecular biology analysis of biopsies allowed a rapid diagnosis.

Prevalence of oropharyngeal beta-lactamase-producing Capnocytophaga spp. in pediatric oncology patients over a ten-year period

Background

The aim of this study was to evaluate the prevalence of beta-lactamase-producing Capnocytophaga isolates in young children hospitalized in the Pediatric Oncology Department of Hôpital Sud (Rennes, France) over a ten-year period (1993–2002).

Methods

In neutropenic children, a periodic survey of the oral cavity allows a predictive evaluation of the risk of systemic infections by Capnocytophaga spp. In 449 children with cancer, 3,053 samples were collected by oral swabbing and plated on TBBP agar. The susceptibility of Capnocytophaga isolates to five beta-lactams was determined.

Results

A total of 440 strains of Capnocytophaga spp. were isolated, 309 (70%) of which were beta-lactamase producers. The beta-lactamase-producing strains were all resistant to cefazolin, 86% to amoxicillin, and 63% to ceftazidime. The proportion of strains resistant to third-generation cephalosporins remained high throughout the ten-year study, while susceptibility to imipenem and amoxicillin combined with clavulanic acid was always conserved.

Conclusion

These results highlight the risk of antibiotic failure in Capnocytophaga infections and the importance of monitoring immunosuppressed patients and testing for antibiotic susceptibility and beta-lactamase production.

Evaluation of the mandibular third molar pericoronitis flora and its susceptibility to different antibiotics prescribed in france

This work assessed the polymicrobial flora of mandibular third molar pericoronitis. Obligate anaerobes were found in almost all cases (32 of 35). Amoxicillin and pristinamycin were the most effective against the flora, particularly aerobic organisms. Metronidazole alone or combined with spiramycin was the most effective drug against obligate anaerobes.

Genetic analysis of an ambler class A extended-spectrum beta-lactamase from Capnocytophaga ochracea

A beta-lactamase gene (cfxA3, 966 bp) was isolated from a beta-lactam-resistant Capnocytophaga ochracea clinical isolate and amplified using primers from the cfxA gene of Bacteroides vulgatus. The MICs of third-generation cephalosporins were much higher than those of the transconjugant Escherichia coli strain. The deduced protein sequence, by comparison with CfxA2 of Prevotella intermedia, had a Y239D substitution and possessed the characteristics of a class A, group 2e beta-lactamase.

Microbiology of mandibular third molar pericoronitis: incidence of beta-lactamase-producing bacteria

OBJECTIVES

The purpose of this study was to evaluate the predominant flora associated with pericoronitis in third molars and to investigate the presence of beta-lactamase-producing strains.

STUDY DESIGN

The third molars in 26 adults were evaluated by cultures with nonselective media and with selective media containing amoxicillin, pristinamycin, spiramycin, metronidazole, and spiramycin plus metronidazole.

RESULTS

In the majority of cases (19/26), the flora found in an anaerobic atmosphere predominated. Obligate anaerobes were present in 21 of the 26 samples. The bacteria most commonly detected were alpha-hemolytic streptococci (26/26) and the genera Prevotella (15/26), Veillonella (15/26), Bacteroides (9/26), and Capnocytophaga (9/26). Amoxicillin and pristinamycin were the most active in reducing the anaerobic cultivable counts. beta-Lactamase-producing strains were detected in 9 samples and were mostly bacteria of the genera Prevotella, Staphylococcus, and Bacteroides.

CONCLUSIONS

These results highlight (1) the diversity of the microflora associated with pericoronitis and the importance of the anaerobic flora and (2) the existence of selection pressure related to the use of beta-lactams that may culminate in failure of prescribed penicillins.

Influence of peracetic acid on adhesion/invasion of Salmonella enterica serotype typhimurium LT2

The influence of peracetic acid (PAA) disinfectant on Salmonella enterica serotype Typhimurium LT2 in sewage effluent was examined by studying its ability to adhere to and invade HeLa cells in vitro. Although the disinfectant produced a decrease of about 5 log units, the bacteria kept their adhesive and invasive abilities. Scanning microscopic observations of the PAA-treated bacteria revealed that PAA caused a loss of external microfilaments and an alteration of membrane structure. Nevertheless, electron-microscopic observations showed that PAA-treated bacteria were still able to adhere to and invade HeLa cells despite the fact that the bacteria seemed to have undergone some structural modifications. With confocal microscopy, the use of anti-actin antibody showed that the contact between the bacteria (with or without PAA treatment) and the HeLa cells activated actinopolymerization of the HeLa cell cytoskeleton.

[Clostridium difficile infection in a Department of Internal Medicine. A consecutive series of 45 patients]

OBJECTIVES AND METHODS

A retrospective study of 45 patients with Clostridium difficile infection over a 4-year period in a department of Internal Medicine.

RESULTS

Mean age was 79 years; sex-ratio (F/M)=1.5; 38% of the patients had neurological or severe psychiatric disorders; 20% had a neoplastic disease. Ninety-three percent of cases had received one or more antibiotics before onset of diarrhea, prescribed mainly for a pulmonary infection. Amoxicillin clavulanic acid and cephalosporins were the most frequently used treatments, respectively in 48% and 40% of cases. For 25 patients (56%) Clostridium difficile-associated diarrhea was considered as a nosocomial infection, and as community-acquired diarrhea in 20 cases (44%). Treatment included isolation of the patient as soon as bacteriological diagnosis was known and specific therapy was instituted by metronidazole or vancomycin for a mean of 18 days. The addition of Saccharomyces boulardii was used in of cases. The clinical course was rapidly favorable for 80% of patients. Five patients died with complications of severe colitis in 2 cases. Mean hospital stay was 49 days (annual mean of the department=10 days).

CONCLUSION

Clostridium difficile diarrhea concerns above all elderly patients with one or more underlying pathologies. Amoxicillin clavulanic acid and third-generation cephalosporins are the most frequently prescribed antibiotics in these cases and have the highest correlation with this infectious complication. This medical problem requires greater knowledge as it causes significant morbidity and increases the risk of prolonged hospital stays.

Osmotic stress-induced genetic rearrangements in Escherichia coli H10407 detected by randomly amplified polymorphic DNA analysis

Randomly amplified polymorphic DNA (RAPD) analysis is a DNA polymorphism assay commonly used for fingerprinting genomes. After optimizing the reaction conditions, samples of Escherichia coli H10407 DNA were assayed to determine the influence of osmotic and/or oligotrophic stress on variations in RAPD banding patterns. Genetic rearrangements or DNA topology variations could be detected as changes in agarose gel electrophoresis banding profiles. A new amplicon generated using DNA extracted from bacteria prestarved by an osmotic stress and resuscitated in rich medium was observed. Enrichment improved recovery of mutator cells and allowed them to be detected in samples, suggesting that DNA modifications, such as stress-induced alterations and supercoiling phenomena, should be taken into consideration before beginning RAPD analyses.

In vitro susceptibilities of Capnocytophaga isolates to beta-lactam antibiotics and beta-lactamase inhibitors

The susceptibilities of 43 pharyngeal isolates of Capnocytophaga to beta-lactam antibiotics, alone or in combination with beta-lactamase inhibitors, were tested by an agar dilution method. The 34 beta-lactamase-positive strains were highly resistant to beta-lactams, but the intrinsic activities of clavulanate, tazobactam, and sulbactam against Capnocytophaga, even beta-lactamase producers, indicates that these beta-lactamase inhibitors could be used for empirical treatment of neutropenic patients with oral sources of infection.

Production of Escherichia coli group I-like heat-labile enterotoxin by Enterobacteriaceae isolated from environmental water

Strains of Klebsiella oxytoca (2), Citrobacter freundii (2), Enterobacter cloacae (1) and Escherichia coli (1) isolated from environmental water were identified as heat-labile enterotoxin (LT) producing strains by immunological methods and polymerase chain amplification. A 322 bp amplified fragment was obtained with specific primers LTR and LTL, and hybridized to a digoxigenin-labelled LTB probe only under low stringency conditions, and not with a cholera toxin probe. These results suggest that Enterobacteriaceae may produce a LT-like toxin antigenically and genetically related to the LT enterotoxin of E. coli.

Influence of peracetic acid on Escherichia coli H10407 strain in laboratory microcosms

The bactericidal properties of peracetic acid (PAA) were tested using Escherichia coli H10407, in sterilized artificial seawater, sewage effluent water, and distilled water microcosms. No LT enterotoxin synthesis was detected by GM1 enzyme-linked immunosorbent assay of the water supernatants, but a specific fragment of the eltB gene was always amplified by polymerase chain reaction for 21 days after PAA treatment. The resuscitation capacity of starved cells was assayed in rich medium and their inability to overcome the effects of PAA stress was observed, despite the emergence of viable but nonculturable cells in microcosms 24 or 48 h after treatment. Moreover, no obvious differences in response were obtained, concerning enterotoxigenesis, between bacteria subjected to osmotic and (or) nutrient starvation-induced stress with or without PAA treatment.

Detection of enterotoxigenic Escherichia coli in water by polymerase chain reaction amplification and hybridization

Enterotoxigenic Escherichia coli was studied in waste water, river water, and seawater from six locations along the west coast of Normandy by using the polymerase chain reaction (PCR) to amplify the heat labile (LT) gene. Cellular DNA was extracted from centrifugation pellets and amplified using PCR. The PCR products were detected by gel electrophoresis and confirmed by hybridization assay, using an 850 base pair HindIII DNA fragment probe from pEWD299 conjugated to digoxigenin and specific for the LT gene. Results of the PCR amplification were compared with those of GM1 enzyme-linked immunosorbent assay, latex agglutination, and colony hybridization. The PCR method was found to be more precise and less time consuming, especially when compared with methods requiring culture of isolates for enumeration of enterotoxigenic E. coli in water.