Anaerobic Infections Research Articles

Evaluation of metronidazole oral monotherapy in anaerobic oral infections.

To evaluate the indications and dosing regimens for oral metronidazole monotherapy (OMM) for the management of oral anaerobic infections (OAIs) other than periodontitis. The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in literature of PubMed/Medline, Scopus, and Cochrane databases. Data were retrieved from reports published in English in the period January 1, 1980 - August 30, 2023. Joanna Briggs Institute Critical Appraisal Tools were used to assess study risk of bias. A total of 228 articles were retrieved from the databases of which 16 met the inclusion criteria necessary for achieving the aims of the study. OAIs in which OMM was used or recommended included pericoronitis; necrotizing ulcerative gingivitis/periodontitis/stomatitis, osteomyelitis, acute periapical infection, and cellulitis. OMM was prescribed in dosages ranging from 200 to 500 mg t.i.d. for periods ranging from 2 to 7 days. Osteomyelitis of the jaw was the only infection for which the dosage regimen of metronidazole was not clearly described. Evidence from the databases searched support the view that OMM has clinical efficacy in the treatment of specific OAIs namely pericoronitis and necrotizing oral infections in immune-competent and immune-compromised patients. The evidence does not support the use of OMM in "deep tissue" infections such as osteomyelitis, and odontogenic infections such as acute apical infection and cellulitis. Clinical trials are warranted to determine the efficacy of OMM in comparison with other antibiotic regimens.

Academician Vladimir Vasilievich Kovanov (1909–1994) (on the 115th anniversary of his birth)

A prominent Soviet surgeon, a well-known specialist in the field of topographic anatomy, operative and military surgery, a talented scientist and teacher, academician (1963) and vice-president (1966) of the USSR Academy of Medical Sciences, honored scientist of the RSFSR (1965), laureate of the USSR State Prize, Rector of the 1st MMI named after I. M. Sechenov (1956–1966), Professor Vladimir Vasilievich Kovanov was born on March 13 (February 28, old style) 1909 in St. Petersburg into a working-class family. In 1931, V. V. Kovanov graduated from the 1st Moscow Medical Institute and continued his postgraduate studies at the Department of Pathological Anatomy under the guidance of Professor A. I. Abrikosova. For medical reasons, he changed his specialization and moved to the Department of Surgery, headed by Academician N. N. Burdenko. During the Great Patriotic War, he worked as a surgeon in a triage hospital in Yaroslavl, in an evacuation hospital in Kazan, then served as the head of the surgical department of the field mobile hospital of the 5th shock army, the chief surgeon of the 44th army and the chief surgeon of the 28th army, in whose ranks he reached to Berlin with the rank of lieutenant colonel in the medical service.In 1946, V. V. Kovanov defended his doctoral dissertation and in 1947, took the position of head of the department of operative surgery and topographic anatomy of the 1st Moscow Medical Institute named after I. M. Sechenov (1947–1988), from 1956 to 1966, was the rector of this institute, since 1988 – consulting professor. Vladimir Vasilievich was the author and co-author of more than 130 scientific works, including 7 monographs and manuals. His main works were devoted to the treatment of chest wounds, anaerobic infection, traumatic shock, the organization of surgical work in the military area, the anatomy of fascia and cellular spaces, surgery of the heart and blood vessels, organ and tissue transplantation.V. Kovanov was awarded two Orders of Lenin, the Order of the Red Star, the Order of the Red Banner, two Orders of the Patriotic War of the 1st degree, two Orders of the Patriotic War of the 2nd degree, the Order of the October Revolution, the Order of the Red Banner of Labor, six medals, and many badges of honor. Academician of the USSR Academy of Medical Sciences V. V. Kovanov died on February 22, 1994 in Moscow and was buried at the Troekurovskoye cemetery.

Bioequivalence Analysis of Clindamycin Hydrochloride Capsules in Healthy Chinese Subjects Under Fasted and Fed Conditions.

Clindamycin is a lincosamide antibiotic for the treatment of staphylococcal, streptococcal, and anaerobic bacterial infections. We conducted a single-center, single-dose, 2-preparation, 2-period, 2-sequence, randomized, open-label, 2×2 crossover study to evaluate the pharmacokinetics (PKs) and safety of the test and reference clindamycin hydrochloride capsules in healthy Chinese subjects under both fasted and fed conditions. Forty-eight subjects were enrolled in the study totally, with 24 subjects in each group. All subjects were asked to take a test or reference preparation, under either fasted or fed condition, and their blood samples were collected and assayed by a validated high-performance liquid chromatography-tandem mass spectrometry method. PK parameters including maximum plasma concentration, area under the plasma concentration-time curve from time 0 to the last concentration, and area under the plasma concentration-time curve from time 0 to infinity were estimated with noncompartmental model and analyzed. Results showed that the PK profiles of the 2 preparations were consistent and met the bioequivalence criteria. Food was identified as a factor that had an impact on clindamycin absorption. The safety of clindamycin hydrochloride capsules was satisfactory. This study proved that the 2 clindamycin hydrochloride capsules were bioequivalent in healthy Chinese subjects under both fasted and fed conditions.

Current issues of using metronidazole in clinical practice. Effects and directions of clinical application

Metronidazole is an important drug in clinical and outpatient practice due to its broad antibacterial and antiprotozoal properties. Metronidazole is effective against anaerobic bacteria and some protozoa such as Trichomonas vaginalis and Giardia lamblia. This makes it indispensable in the treatment of infections of various etiologies. The review article contains current information about the clinical pharmacology of metronidazole and its place in the pharmacotherapy of infectious diseases. General and specific issues of the use of metronidazole in the practice of GPs, surgeons, obstetrician-gynecologists, and other specialists are considered. Information is provided on the possibilities and indications for the use of metronidazole in the eradication of Helicobacter pylori, in radiation therapy for cancer patients, dermatovenereology, dentistry, treatment of protozoal infections, as well as in alcoholism. Metronidazole is often used in combination with other antibiotics to enhance the antimicrobial effect, especially in cases of mixed infections or when it is necessary to cover a wider range of pathogens. In surgical practice, metronidazole is used to prevent infectious complications after operations on the abdominal and pelvic organs, where the risk of anaerobic infection is high. In an environment of increasing antibiotic resistance, metronidazole remains an effective treatment against many anaerobic pathogens, highlighting its place in modern practice.

Utilization of MALDI-TOF MS in the etiological diagnosis of deep-seated anaerobic bacterial infections

PurposeDeep-seated abscesses can be caused by a wide array of bacteria in various anatomical sites, the precise identification of which is crucial for implementing organism-specific treatments which can reduce morbidity and mortality. MALDI-TOF MS is a powerful proteomic method for the swift and accurate identification of anaerobic organisms. The aim of this study was to investigate deep-seated infections by MALDI-TOF MS (in comparison to VITEK®2 ANC ID card and phenotypic biochemical tests) and to determine the susceptibility pattern of identified microorganisms. Materials and methodsA total of 104 samples from patients suspected of deep-seated infections were aseptically collected and subjected to microscopy, aerobic/anaerobic cultures and subsequent identification via MALDI-TOF MS followed by antimicrobial susceptibility testing. Anaerobic bacteria were also identified using the VITEK-2 system and phenotypic biochemical tests. ResultsOut of the 104 samples tested, 41.3 % (43/104) showed positive results, predominantly in pus specimens (88 %). Mixed infections were found in 21 % of the positive cases. Of the 52 organisms identified from positive specimens, 19.2 % (10/52) were obligate anaerobes, with Bacteroides fragilis group being the most prevalent, followed by both Clostridium perfringens and Clostridium sporogenes respectively. Escherichia coli was observed to be the most common facultative anaerobic isolate. All obligate anaerobes were successfully identified to the species level via MALDI-TOF MS. In contrast, the VITEK®2 ANC ID card identified only 40 % (4/10) anaerobic bacteria to the species level. All obligate anaerobic organisms showed 100 % susceptibility to metronidazole, vancomycin and ertapenem. 25 % of the Bacteroides spp. and 50 % of Clostridium perfringens isolates were found to be resistant to clindamycin. ConclusionMALDI-TOF MS proves as a beneficial diagnostic tool for bacterial identification, eliminating the labour-intensive and time consuming conventional microbiological methods. Its accuracy of bacterial detection further helps in combating antibiotic resistance and improving patient outcomes in deep-seated infections.

An Eleven-Year Retrospective Survey of Anaerobic Bloodstream Infection in Adults in a General Hospital.

During conditions accompanied by the disruption of normal mucosal barriers, anaerobic bacteria, which a part of normal human mucosal microflora, may cause various infections. In this study, clinical features of anaerobic bloodstream infections (BSI) in a general hospital in China were investigated. Patients with anaerobic BSI were retrospectively enrolled between 2012 and 2022. Demographic data, clinical manifestations, antibiotic treatments, and disease outcomes were analyzed. In total, 391 anaerobic bacterial strains were isolated from 381 patients aged older than 11 years of age. Given that medical records of 47 patients were missing, 334 patients were included in the clinical investigation. Patients with anaerobic BSI included in the study were predominantly older than 50 years of age. Intra-abdominal infections were the most common source of anaerobic BSI (59%), followed by those of the female genital tract (10.2%) and lower respiratory tract (7.2%). Among the isolates, Bacteroides and Clostridium spp. were the most frequently isolated anaerobes. Most of the patients received antibiotic therapy. The crude mortality was 4.5%. The detection rate of anaerobic BSI in Ningxia, China, remained relatively stable from 2012 to 2022. These results provide a reference for the diagnosis and empirical treatment of anaerobic BSI in this region of China. Continuous mul-ticenter studies should be conducted to monitor the incidence of anaerobic BSI and drug resistance of anaerobic isolates to improve the treatment outcomes of patients.

Diagnostic Challenges and Management of Non-Odontogenic Toothache: A Case of Unilateral Pansinusitis Mimicking Dental Pain

This case report details the diagnostic challenge and subsequent management of a 38-year-old male patient who presented with severe, sharp, and non-localized pain in the right maxillary distal area. Initial¬ly unresponsive to non-steroidal anti-inflammatory drugs and antibiotics, the patient’s symptoms deviat¬ed from typical odontogenic pain characteristics. Comprehensive dental examinations revealed minimal pathologies, challenging initial assumptions of dental-origin pain. Advanced diagnostic imaging, including Orthopantomography and Cone Beam Computed Tomography (CBCT), was pivotal in identifying unilat¬eral pansinusitis, with notable obstruction in the maxillary, ethmoid, and frontal sinuses. Further microbi¬ological analysis confirmed a Staphylococcus aureus and anaerobic infection, refocusing the diagnosis to a non-odontogenic source. The patient underwent a targeted 14-day complex antibiotic regimen, supple¬mented with local treatments including Nasonex nasal spray and saline nasal irrigations. This integrative approach resulted in marked symptom improvement and was instrumental in the patient’s recovery. This case highlights the critical need for thorough evaluation in distinguishing between odontogenic and non-od¬ontogenic sources of orofacial pain, ensuring accurate diagnosis and effective treatment.

Clinical signs and post-mortem lesions caused by clostridial enterotoxemia in rabbits

Enterotoxemia, accompanied by diarrhea and bloating, is still a matter of pressing concern to the rabbit farming. Clostridia bacteria are often isolated from the internal organs of rabbits that have died of an anaerobic infection. Clostridial infection, manifested in various forms, is a major problem for veterinarians. The following drivers contribute to the emergence of the infectious disease: malnutrition (insufficient fiber intake); non-compliance with hygiene requirements for animal handling; unsustainable use of antibacterial drugs; gastrointestinal congestion. All these drivers can disrupt healthy caecum microflora due to changes in the gastrointestinal environment. Low-fiber diets result in slow cecum motility, thus, delaying transit of the intestinal contents and eventually changing the microflora. Use of antibiotics together with stress make Clostridia accumulate in the gastrointestinal tract, at the same time, reducing the number of microorganisms of other groups. The first signs of toxicoinfection are observed when rabbit kits are weaned from does. Clinical manifestation begins with bloating, weakness, inappetence, which ultimately lead to death. Observations have shown that the risk group includes rabbit kits weaned from the 35–77-day old does. Mortality was less reported in breeding stock and among replacement young animals. Autopsy revealed signs of enterotoxemia: serous-catarrhal gastritis, serous-hemorrhagic lymphonodulitis, degenerated kidneys, liver and heart muscle; passive congestion of lungs and pulmonary edema. Microbiological diagnosis revealed Clostridium histolyticum and Clostridium perfringens species known for their pronounced toxigenic profile, most often bacteria were found in the stomach, intestines and heart.

Third Kuwaiti Multicenter Survey of Antibiotic Susceptibility of Anaerobic Bacteria: A Comparative Analysis of 20-Year Data.

Objective: This study aimed to evaluate antibiotic susceptibility and antimicrobial resistance trends among clinically significant anaerobes in Kuwait hospitals from 2013 to 2022, comparing these findings with data from 2002 to 2012. Methods: The study prospectively collected 2,317 anaerobic isolates from various body sites across four Kuwaiti hospitals between January 2013 and December 2022. The minimum inhibitory concentrations for 11 antianaerobic antibiotics were determined using E-test methodology. The study analyzed trends and resistance rates across two periods: 2013-2017 and 2018-2022, using statistical analysis for resistance comparison. Results: Of the 2,317 isolates, most were from wounds (42.2%), fluids (28.0%), and tissues (20.5%). Bacteroides fragilis was the most common pathogen (34.0%), followed by Prevotella bivia (13.4%). Over 90% of isolates were susceptible to imipenem, meropenem, tigecycline, and metronidazole, whereas lower susceptibility was observed for penicillin, amoxicillin-clavulanic acid, and clindamycin. Notable differences in resistance profiles since 2002 were observed, especially in amoxicillin-clavulanic acid, piperacillin, piperacillin-tazobactam, and clindamycin. Conclusion: Owing to detected resistance to all antibiotics, susceptibility testing for anaerobic isolates is recommended in severe infections to ensure effective antimicrobial therapy. Continuous surveillance is crucial for developing antibiotic policies to manage invasive anaerobic infections.

A clinical case of treatment for anaerobic infection in a patient with mine blast trauma in the intensive care unit

A clinical case of treatment for anaerobic infection in a patient with mine blast trauma in the intensive care unit

The emergence of metronidazole-resistant Prevotella bivia harboring nimK gene in Japan.

Metronidazole (MTZ) is an important antimicrobial agent in anaerobic infections and is widely used in clinical settings. The rate of MTZ resistance in anaerobic bacteria has been increasing in recent years, and the nim gene (nitro-imidazole reductase) is one of the resistance mechanisms. Prevotella bivia is found in humans in the urinary tract and vagina and is known to cause infections in some cases. One of the nim genes, nimK, has recently been discovered in this species of bacteria, but there are no reports of antimicrobial resistance (AMR)-related regions in its whole genome level. In this study, we analyzed the AMR region of nimK-positive P. bivia derived from clinical specimens based on comparisons with other anaerobic genomes. P. bivia was found to be engaged in horizontal gene transfer with other anaerobic bacteria, and the future spread of the nimK gene is a concern.

Dual roles of photosynthetic hydrogel with sustained oxygen generation in promoting cell survival and eradicating anaerobic infection

Tissue engineering offers a promising alternative for oral and maxillofacial tissue defect rehabilitation; however, cells within a sizeable engineered tissue construct after transplantation inevitably face prolonged and severe hypoxic conditions, which may compromise the survivability of the transplanted cells and arouse the concern of anaerobic infection. Microalgae, which can convert carbon dioxide and water into oxygen and glucose through photosynthesis, have been studied as a source of oxygen supply for several biomedical applications, but their promise in orofacial tissue regeneration remains unexplored. Here, we demonstrated that through photosynthetic oxygenation, Chlamydomonas reinhardtii (C. reinhardtii) supported dental pulp stem cell (DPSC) energy production and survival under hypoxia. We developed a multifunctional photosynthetic hydrogel by embedding DPSCs and C. reinhardtii encapsulated alginate microspheres (CAMs) within gelatin methacryloyl hydrogel (GelMA) (CAMs@GelMA). This CAMs@GelMA hydrogel can generate a sustainable and sufficient oxygen supply, reverse intracellular hypoxic status, and enhance the metabolic activity and viability of DPSCs. Furthermore, the CAMs@GelMA hydrogel exhibited selective antibacterial activity against oral anaerobes and remarkable antibiofilm effects on multispecies biofilms by disrupting the hypoxic microenvironment and increasing reactive oxygen species generation. Our work presents an innovative photosynthetic strategy for oral tissue engineering and opens new avenues for addressing other hypoxia-related challenges.

Metabolic changes associated with polysaccharide utilization reduce susceptibility to some β-lactams in Bacteroides thetaiotaomicron.

Antibiotic therapy alters bacterial abundance and metabolism in the gut microbiome, leading to dysbiosis and opportunistic infections. Bacteroides thetaiotaomicron (Bth) is both a commensal in the gut and an opportunistic pathogen in other body sites. Past work has shown that Bth responds to β-lactam treatment differently depending on the metabolic environment both in vitro and in vivo. Studies of other bacteria show that an increase in respiratory metabolism independent of growth rate promotes susceptibility to bactericidal antibiotics. We propose that Bth enters a protected state linked to an increase in polysaccharide utilization and a decrease in the use of simple sugars. Here, we apply antibiotic susceptibility testing, transcriptomic analysis, and genetic manipulation to characterize this polysaccharide-mediated tolerance (PM tolerance) phenotype. We found that a variety of mono- and disaccharides increased the susceptibility of Bth to several different β-lactams compared to polysaccharides. Transcriptomics indicated a metabolic shift from reductive to oxidative branches of the tricarboxylic acid cycle on polysaccharides. Accordingly, supplementation with intermediates of central carbon metabolism had varying effects on PM tolerance. Transcriptional analysis also showed a decrease in the expression of the electron transport chain (ETC) protein NQR and an increase in the ETC protein NUO, when given fiber versus glucose. Deletion of NQR increased Bth susceptibility while deletion of NUO and a third ETC protein NDH2 had no effect. This work confirms that carbon source utilization modulates antibiotic susceptibility in Bth and that anaerobic respiratory metabolism and the ETC play an essential role.IMPORTANCEAntibiotics are indispensable medications that revolutionized modern medicine. However, their effectiveness is challenged by a large array of resistance and tolerance mechanisms. Treatment with antibiotics also disrupts the gut microbiome which can adversely affect health. Bacteroides are prevalent in the gut microbiome and yet are frequently involved in anaerobic infections. Thus, understanding how antibiotics affect these bacteria is necessary to implement proper treatment. Recent work has investigated the role of metabolism in antibiotic susceptibility in distantly related bacteria such as Escherichia coli. Using antibiotic susceptibility testing, transcriptomics, and genetic manipulation, we demonstrate that polysaccharides reduce β-lactam susceptibility when compared to monosaccharides. This finding underscores the profound impact of metabolic adaptation on the therapeutic efficacy of antibiotics. In the long term, this work indicates that modulation of metabolism could make Bacteroides more susceptible during infections or protect them in the context of the microbiome.

Infections caused by Slackia exigua: A single-center experience and literature review.

Slackia exigua, originally classified as Eubacterium exiguum, is a Gram-positive, asaccharolytic, rod-shaped anaerobic bacterium. The virulence factors of S. exigua have not been accurately identified. The objective of the study is to evaluate the pathogenic potential of S. exigua by presenting the cases of infections diagnosed at our hospital laboratory. Additionally, we reviewed the literature to summarize the experience with S. exigua infections to clarify, in the light of current knowledge, the clinical picture, diagnostic, and therapeutic issues related to this anaerobic bacterium. We reported eleven severe human infections caused by S. exigua. All patients required hospitalization. Nine of the cases involved chronic infections in the stomatognathic system, in two patients, skin infections were diagnosed. As it is known, S. exigua is a component of the human microbiota; however, it can cause opportunistic infections, particularly in the case of translocation outside its natural habitat. A critical literature analysis revealed that S. exigua can be responsible for bacteremia, meningitis, tissue necrosis, periprosthetic joint infection, and osteomyelitis. Several studies have been published regarding the determination of drug susceptibility of S. exigua. The isolated strains were susceptible to most antibiotics used for the treatment of anaerobic infections. The interpretation of antimicrobial susceptibility testing for some slow-growing in vitro, infrequently causing infections anaerobic bacteria, such as S. exigua, is based on The European Committee on Antimicrobial Susceptibility Testing (EUCAST) additional guidance taking into account the determination of drug susceptibility for groups of microorganisms for which cut-off values have not been developed.

Chloramphenicol alleviates 5-fluorouracil-induced cellular senescence through activation of autophagy.

5-Fluorouracil (5-FU) is a first-line treatment for colorectal cancer, but side effects such as severe diarrhea are common in clinical use and have been linked to its induction of normal cell senescence. Chloramphenicol (CAP) is an antibiotic commonly used to treat typhoid or anaerobic infections, but its senescence-related aspects have not been thoroughly investigated. Here, we used 5-FU to induce senescence in human umbilical vein endothelial cells (HUVECs) and investigated the relationship between CAP and cellular senescence at the cellular level. In a model of cellular senescence induced by 5-FU treatment, we discovered that CAP treatment reversed the rise in the percentage of senescence-associated galactosidase (SA-β-gal)-positive cells and decreased the expression of senescence-associated proteins (p16), senescence-associated genes (p21), and senescence-associated secretory phenotypes (SASPs: IL-6, TNF-α). In addition, CAP subsequently restored the autophagic process inhibited by 5-FU and upregulated the levels of autophagy-related proteins. Mechanistically, we found that CAP restored autophagic flux by inhibiting the mTOR pathway, which in turn alleviated FU-induced cellular senescence. Our findings suggest that CAP may help prevent cellular senescence and restore autophagy, opening up new possibilities and approaches for the clinical management of colorectal cancer.

A nano-oxygen generator for enhanced light-controlled elimination of anaerobic bacteria in periodontal infections

Using nanomaterials with photodynamic therapy (PDT) to combat bacterial infections including periodontal infections has attracted the attention of researchers because of their high efficiency, simplicity and low susceptibility to drug resistance. However, the therapeutic effectiveness is threatened by the endogenous accumulation of hydrogen peroxide and insufficient amounts of the substrate oxygen. Here, we report a microporous Zr porphyrin carboxylate metal-organic framework (MOF) PCN-222 doped with platinum nanozymes, Pt@PCN-222, to reshape the microenvironment that is not conducive to the recovery of infected tissue and further promote recovery after periodontal tissue infection. This MOFdoped with platinum nanozymes can remove excessive endogenous hydrogen peroxide and produce dissolved oxygen simultaneously. This framework can effectively alleviate anaerobic bacterial infection in periodontal tissue, including efficiently killing the bacteria and reducing the level of inflammation in tissue. This work provides a new strategy to solve the long-term clinical challenge of anaerobic bacterial infections in periodontal tissue and proposes an innovative approach to improve treatment.

Infekcje wywołane przez Slackia exigua. Przegląd literatury i obserwacje własne

Slackia exigua, originally classified as Eubacterium exiguum, is a Gram-positive, asaccharolytic, rod-shaped anaerobic bacterium. The virulence factors of S. exigua have not been accurately identified. The objective of the study is to evaluate the pathogenic potential of S. exigua by presenting the cases of infections diagnosed at our hospital laboratory. Additionally, we reviewed the literature to summarize the experience with S. exigua infections to clarify, in the light of current knowledge, the clinical picture, diagnostic, and therapeutic issues related to this anaerobic bacterium. We reported eleven severe human infections caused by S. exigua. All patients required hospitalization. Nine of the cases involved chronic infections in the stomatognathic system, in two patients, skin infections were diagnosed. As it is known, S. exigua is a component of the human microbiota; however, it can cause opportunistic infections, particularly in the case of translocation outside its natural habitat. A critical literature analysis revealed that S. exigua can be responsible for bacteremia, meningitis, tissue necrosis, periprosthetic joint infection, and osteomyelitis. Several studies have been published regarding the determination of drug susceptibility of S. exigua. The isolated strains were susceptible to most antibiotics used for the treatment of anaerobic infections. The interpretation of antimicrobial susceptibility testing for some slow-growing in vitro, infrequently causing infections anaerobic bacteria, such as S. exigua, is based on The European Committee on Antimicrobial Susceptibility Testing (EUCAST) additional guidance taking into account the determination of drug susceptibility for groups of microorganisms for which cut-off values have not been developed.

Metronidazole-induced neurotoxicity: Possible central serotonergic and noradrenergic system involvement

Background: Metronidazole is a synthetic 5-nitroimidazole antibiotic. It remains a first-line therapy for anaerobic, parasitic, and bacterial infections in human and veterinary medicine. However, Metronidazole-induced neurotoxicity is a rising challenge. The mechanism of neurotoxicity induction is still unknown. Objective: To investigate a possible interference of metronidazole with central monoaminergic mechanisms using the Forced Swim Test. Methods: sixty adult rats were divided into 10 groups (n=10 for metronidazole and saline, n=5 for other groups). Group 1 = 5 ml/kg normal saline; Group 2 = 50 mg/kg metronidazole; group 3= 15 mg/kg imipramine; Group 4 =15 mg/kg imipramine + 50 mg/kg metronidazole. Group 5 = 5 mg/kg fluoxetine; Group 6 received 5 mg/kg fluoxetine + 50 mg/kg metronidazole; Group 7 = labetalol 10 mg/kg; Groups 8, 9 and 10 received labetalol 10 mg/kg + 50 mg/kg metronidazole, PCPA (p-chlorophenylalanine) 100 mg/kg and PCPA 100 mg/kg + 50 mg/kg metronidazole daily X 28 days. On day 28, FST was done 1h after the respective treatments. On day 29, blood samples were collected under halothane anesthesia for hematological assessment. Results: Immobility time increased (P<0.01) in the groups treated with metronidazole, labetalol, PCPA, labetalol + metronidazole, and PCPA+ metronidazole. Swimming was reduced by metronidazole, PCPA, metronidazole + PCPA and metronidazole + labetalol. Metronidazole + labetalol reduced climbing. These effects were not reduced by co-treatment with imipramine or fluoxetine. White blood cell count increased (p<0.01) in all treatment groups. Lymphocyte percent increased in the metronidazole-treated groups. Conclusion: Interference with postsynaptic central monoaminergic neurotransmission and immunomodulation may contribute to metronidazole-induced neurotoxicity.

Metronidazole may display anti-inflammatory features in periodontitis treatment: A scoping review.

Metronidazole (MTZ) is an antimicrobial agent used to treat anaerobic infections. It has been hypothesized that MTZ may also have anti-inflammatory properties, but the evidence is limited and has not been previously reviewed. Thus, this scoping review aimed to answer the following question: "What is the evidence supporting anti-inflammatory properties of metronidazole that are not mediated by its antimicrobial effects?" A scoping review was conducted according to the PRISMA-ScR statement. Five databases were searched up to January 2023 for studies evaluating the anti-inflammatory properties of MTZ used as monotherapy for treating infectious and inflammatory diseases. A total of 719 records were identified, and 27 studies (21 in vivo and 6 in vitro) were included. The studies reported experimental evidence of MTZ anti-inflammatory effects on (1) innate immunity (barrier permeability, leukocyte adhesion, immune cell populations), (2) acquired immunity (lymphocyte proliferation, T-cell function, cytokine profile), and (3) wound healing/resolution of inflammation. Taken together, this scoping review supported a potential anti-inflammatory effect of MTZ in periodontitis treatment. We recommend that future clinical studies should be conducted to evaluate specific MTZ anti-inflammatory pathways in the treatment of periodontitis.

<i>Parvimonas micra</i>-Induced Paraspinal Abscess and Pyogenic Spondylitis Following Dental Extraction: A Case Report with a Brief Literature Review

The increasing prevalence of pyogenic spondylitis in older adults is primarily driven by Staphylococcus aureus. Cases caused by anaerobic bacteria are rare. This report focuses on a 71-year-old man diagnosed with spondylitis due to an anaerobic bacterial infection. The causative pathogen—Parvimonas micra—is typically found in the oral cavity. Interestingly, the patient had undergone a tooth extraction before the diagnosis. He was successfully treated with antibiotics; therefore, surgery was not necessary. This case is notable for the uncommon infective organism and, along with a concise literature review, this report provides valuable insights for the medical community.