Anaerobic Infections Research Articles

Roving methyltransferases generate a mosaic epigenetic landscape and influence evolution in Bacteroides fragilis group

Three types of DNA methyl modifications have been detected in bacterial genomes, and mechanistic studies have demonstrated roles for DNA methylation in physiological functions ranging from phage defense to transcriptional control of virulence and host-pathogen interactions. Despite the ubiquity of methyltransferases and the immense variety of possible methylation patterns, epigenomic diversity remains unexplored for most bacterial species. Members of the Bacteroides fragilis group (BFG) reside in the human gastrointestinal tract as key players in symbiotic communities but also can establish anaerobic infections that are increasingly multi-drug resistant. In this work, we utilize long-read sequencing technologies to perform pangenomic (n = 383) and panepigenomic (n = 268) analysis of clinical BFG isolates cultured from infections seen at the NIH Clinical Center over four decades. Our analysis reveals that single BFG species harbor hundreds of DNA methylation motifs, with most individual motif combinations occurring uniquely in single isolates, implying immense unsampled methylation diversity within BFG epigenomes. Mining of BFG genomes identified more than 6000 methyltransferase genes, approximately 1000 of which were associated with intact prophages. Network analysis revealed substantial gene flow among disparate phage genomes, implying a role for genetic exchange between BFG phages as one of the ultimate sources driving BFG epigenome diversity.

Recent Trends in Antimicrobial Resistance among Anaerobic Clinical Isolates.

Anaerobic bacteria are normal inhabitants of the human commensal microbiota and play an important role in various human infections. Tedious and time-consuming, antibiotic susceptibility testing is not routinely performed in all clinical microbiology laboratories, despite the increase in antibiotic resistance among clinically relevant anaerobes since the 1990s. β-lactam and metronidazole are the key molecules in the management of anaerobic infections, to the detriment of clindamycin. β-lactam resistance is usually mediated by the production of β-lactamases. Metronidazole resistance remains uncommon, complex, and not fully elucidated, while metronidazole inactivation appears to be a key mechanism. The use of clindamycin, a broad-spectrum anti-anaerobic agent, is becoming problematic due to the increase in resistance rate in all anaerobic bacteria, mainly mediated by Erm-type rRNA methylases. Second-line anti-anaerobes are fluoroquinolones, tetracyclines, chloramphenicol, and linezolid. This review aims to describe the up-to-date evolution of antibiotic resistance, give an overview, and understand the main mechanisms of resistance in a wide range of anaerobes.

Review on Chloramphenicol Antibiotic

The Chloramphenicol is d-threo-2,2-dichloro-N-[β-hydroxy-α-(hydroxymethyl)]-n-nitropheny-lacetamide, a bacterioststic and highly effective antibacterial against $ (+) and gr (-) ocular pathogenic bacteria causing conjunctivitis or corneal ulcers. Chloramphenicol is used in the treatment of bacterial infections. It is used to treat certain types of serious infections caused by bacteria when other antibiotics cannot be used Chloramphenicol is used to treat serious infections in different parts of the body. It is sometimes given with other antibiotics. However, chloramphenicol should not be used for colds, flu, other virus infections, sore throats or other minor infections, or to prevent infections. Chloramphenicol widely used in Chloramphenicol is a medication used in the management and treatment of superficial eye infections such as bacterial conjunctivitis, and otitis externa. It has also been used for the treatment of typhoid and cholera. Chloramphenicol is an antibiotic and is in the class of antimicrobials that inhibits protein synthesis. Chloramphenicol is evaluated for Haemophilus influenzae infections, anaerobic infections, salmonellosis, Rocky Mountain spotted fever, and eye infections.

Fluorescence and photothermal dual-readout phthalocyanine-fluorescein conjugate for detection and photothermal sterilization of anaerobic bacteria

Anaerobic bacterial infection is a common but serious side-effect of dental implant, therefore, the development of new type of antimicrobials that can be applied in situ surgery area to avoid post-operation infection is highly desired. Herein, photothermal agent of silicon phthalocyanine-fluorescein conjugate, SiPc-FITC, is constructed via covalent bond. Comparing with the great majority of organic photothermal agents that based on H-aggregation induced nanocomposites requiring time-consuming uptake by bacteria as well as blue-shifted absorption and fluorescence quenching, SiPc-FITC demonstrates remarkable photothermal conversion efficiency in monomeric state (η = 29.0%) in aqueous solution along with favorable fluorescence emission, which not only significantly accelerate uptake rate of SiPc-FITC but also simplify clinic formulation process. Antibacterial experiments showed that both Gram-positive and Gram-negative anaerobic bacteria were completely eliminated within a few minutes when SiPc-FITC was mixed with bacteria and immediately irradiated with an 808 nm laser. As the results, SiPc-FITC is a multifunctional photothermal bactericide that can be used for fluorescence and photothermal dual readout in situ NIR photothermal sterilization to prevent post-operative infection for dental implant.

Anemia in patients with necrotizing soft tissue infections, pathogenetic and prognostic value

BACKGROUND: Necrotizing soft tissue infection is one of the most severe life-threatening surgical infections with a very high mortality rate. A characteristic feature of necrotizing soft tissue infection is the rapid development of anemia, the causes and prognostic value of which are not well understood.
 AIM: The purpose of this study was to investigate the timing, development, and dynamics of anemia in generalized forms of necrotizing infection to identify clinical and bacteriological factors associated with its development.
 MATERIALS AND METHODS: 129 patients with necrotizing soft tissue infection who were treated from 09.2015 to 12.2019 in the department of purulent-septic surgery at Hospital of the Holy Great Martyr George were examined. All patients received surgical treatment, laboratory hematological, biochemical examination, bacteriological examination of blood, and wound discharge. Overall, 22 patients suffered from systemic inflammatory response syndrome, 63 patients with sepsis, and 41 patients with septic shock.
 RESULTS: The Counts of hemoglobin and red blood cells in necrotizing soft tissue infection patients with sepsis revealed the anemia already during the first day and then from the 15th day of the disease, the red blood cell values began to rise in the patients who survived. However, continued to decrease in the deceased patients. In the group of deceased sepsis patients from day 3 of hospitalization, correlations between red blood cells count and potassium ion concentration (r = 0.318; p 0.01), and red blood cells count and total plasma protein (r = 0.30; p 0.01) became significant. Among patients with hemoglobin 110 g/L on the day of hospitalization, 36 of 67 (53.7%) patients died, and among those with hemoglobin levels 110 g/L, 20 of 62 (32.2%) patients died (p = 0.004). The highest lethality was registered patients who suffered from wound discharge Klebsiella pneumoniae (12 of 18, 66.7%) or anaerobic infection, but marked anemia was noted only in patients with anaerobic infection (Proteus spp., Clostridium spp., Bacteroide spp.) (8 out of 12, 66.7%).
 CONCLUSIONS: We attribute the development of anemia in sepsis patients to the destruction of red blood cells. The type of infectious agent influences both the mortality rate and the degree of anemia, which is probably related to the ability of bacteria to destroy red blood cells.

Anaerobic Profile of Intra-abdominal Infections – A 23-Year Retrospective Study

Obligate anaerobes, which are part of normal intestinal flora are now gaining pathogenic potential by becoming more virulent and causing moderate to severe abdominal infections. Moreover, there is delay in initiation of appropriate antimicrobial therapy. The study aimed to describe and analyse 23 years data on anaerobic intra – abdominal infections in regards to the distribution and antimicrobial susceptibility patterns of the obligate anaerobes which were isolated from various intra – abdominal infections. The demographic and microbiological data was retrieved from the microbiology departmental registers. Total number of cases/specimen were 1124. Bacteroides fragilis group (238) (56%) and Peptostreptococcus sp (109) (25%) amounted to the majority of the isolates. Rare anaerobes like Clostridium sporogenes, Propionibacterium sp, Clostridium bifermentans and Fusobacterium varium were also isolated. Majority of mixed anaerobic infections were contributed by Bacteroides fragilis group and Peptostreptococcus sp (99) out of 102 mixed anaerobic infections). Chronic alcoholism was the most common predisposing condition (p value <0.05). Among the antimicrobials which were used by the clinicians for treating the infection, only Metronidazole was tested for its susceptibility pattern. One isolate was resistant to metronidazole (Diameter of inhibition zone was 6 mm). As they are fastidious they usually go unnoticed. Hence, this descriptive study intends to bring light on the large number of various obligate anaerobes and the potential diseases that they can cause and also the need for their antibiotic susceptibility testing to look for antimicrobial resistance among the isolates.

Microbiology and Antibiotic Resistance Profiles of Orbital Subperiosteal Abscesses: A Comparison of Pediatric, Adolescent, and Adult Populations.

The purpose of this study was to compare the microbiology and antibiotic resistance profiles of orbital subperiosteal abscesses (SPA) among 3 age cohorts. A retrospective study was conducted at a tertiary care center through a medical record search to identify patients with orbital cellulitis and SPA on imaging from January 1, 2000 to September 10, 2022. Patients were categorized into pediatric (<9 years old), adolescent (9-18 years old), and adult (>18 years old) cohorts. Primary outcomes included culture and antibiotic susceptibility results. Secondary outcomes included antibiotic therapy and surgical intervention. Of the 153 SPA patients included, 62 (40.5%) were in the pediatric cohort (4 months-8 years, mean 5.0 ± 2.7), 51 (33.3%) were adolescent (9-18 years, 12.7 ± 2.8), and 40 (26.1%) were adult (19-95, 51.8 ± 19.3). Viridians group Streptococci were the most frequent organisms isolated across groups. The anaerobic infection rate was higher in the adult compared to the pediatric group (23.0% vs, 4.0%, p = 0.017), while that of the adolescent did not differ significantly from either. Pediatric patients carried a lower rate of clindamycin resistance than adolescent and adult cohorts, who shared similar rates (0 vs. 27.0% and 28.0%, respectively; p = 0.016). There were progressive increases in duration of intravenous antibiotic therapy ( p < 0.195) and rate of surgical intervention ( p < 0.001) going from younger to older cohorts. Organisms isolated from orbital SPA from the past 2 decades demonstrate a predominance of Streptococcal species. Older age may be associated with anaerobic infection, clindamycin resistance, and more aggressive management. Adolescent infections are more similar to adult rather than pediatric counterparts but may require less aggressive management than the former.

Outcomes of surgical treatment with patterns of bacterial culture and antimicrobial susceptibility testing in cases of cervical abscessation in dogs: 82 cases (2018–2021)

Objective: The objective of this study was to summarize the presentation, diagnosis, and outcome for dogs surgically treated for chronic cervical abscessation following suspected or reported cervical or oropharyngeal trauma, as well as to report on culture results and antimicrobial susceptibility patterns.Results: Eighty-two dogs were identified by retrospective review. Successful surgical outcome was achieved in 92.7% of dogs. Abscess recurrence was confirmed or suspected in 6/82 (7.3%) cases, and surgical intervention for abscess recurrence was performed in 4/82 (4.9%) cases. Foreign material was identified at surgery in 5/82 (6%) cases. Incisional healing complications were noted in 9/82 (10.9%) cases and required additional surgery in 5/82 (6%) cases. Twenty-three (28%) dogs had negative culture results. The results of antimicrobial sensitivity testing led to a change in antimicrobial treatment in only 9% of cases.Surgically treated cervical abscessation carries a good prognosis with a low incidence of recurrence in this cohort (in contrast to previous reports), despite low frequency of foreign body removal or identification of the underlying cause of the abscess. Excision of chronic inflammatory tissue may not be necessary for a successful outcome, contrary to previous recommendations. Multi-pathogen infections and anaerobic infections are commonly encountered.

Ruthenium(II) Polypyridyl Complexes and Metronidazole Derivatives: A Powerful Combination in the Design of Photoresponsive Antibacterial Agents Effective under Hypoxic Conditions

Ruthenium(II) polypyridyl complexes (RPCs) are gaining momentum in photoactivated chemotherapy (PACT), thanks to the possibility of overcoming the classical reliance on molecular oxygen of photodynamic therapy while preserving the selective drug activation by using light. However, notwithstanding the intriguing perspectives, the translation of such an approach in the development of new antimicrobials has been only barely considered. Herein, MTZH-1 and MTZH-2, two novel analogues of metronidazole (MTZ), a mainstay drug in the treatment of anaerobic bacterial infections, were designed and inserted in the strained ruthenium complexes [Ru(tpy)(dmp)(MTZ-1)]PF6 (Ru2) and [Ru(tpy)(dmp)(MTZ-2)]PF6 (Ru3) (tpy = terpyridine, dmp = 2,9-dimethyl-1,10-phenanthroline) (Chart 1). Analogously to the parental compound [Ru(tpy)(dmp)(5NIM)]PF6 (Ru1) (5-nitroimidazolate), the Ru(II)-imidazolate coordination of MTZ derivatives resulted in promising Ru(II) photocages, capable to easily unleash the bioactive ligands upon light irradiation and increase the antibacterial activity against Bacillus subtilis, which was chosen as a model of Gram-positive bacteria. The photoreleased 5-nitroimidazole-based ligands led to remarkable phototoxicities under hypoxic conditions (<1% O2), with the lead compound Ru3 that exhibited the highest potency across the series, being comparable to the one of the clinical drug MTZ. Besides, the chemical architectures of MTZ derivatives made their interaction with NimAunfavorable, being NimA a model of reductases responsible for bacterial resistance against 5-nitroimidazole-based antibiotics, thus hinting at their possible use to combat antimicrobial resistance. This work may therefore provide fundamental knowledge in the design of novel photoresponsive tools to be used in the fight against infectious diseases. For the first time, the effectiveness of the "photorelease antimicrobial therapy" under therapeutically relevant hypoxic conditions was demonstrated.

Geographic patterns of antimicrobial susceptibilities for Bacteroides spp. worldwide: Results from the Antimicrobial Testing Leadership and Surveillance (ATLAS) programme, 2007–2020

Antimicrobial susceptibilities of 4,973 Bacteroides species isolates recovered from various sources of patients from 12 countries (99.6% from European countries) in the Antimicrobial Testing Leadership and Surveillance (ATLAS) program, 2007-2020, were investigated. The minimum inhibitory concentrations (MICs) of the isolates with six commonly used agents were determined using the agar dilution method. Among the isolates, ten Bacteroides species were included: B. fragilis (n = 3,180, 64.0%) was most frequently encountered, followed by B. thetaiotaomicron (n = 675) and B. ovatus (n = 409). During the 14 years, the proportion of B. fragilis declined, but the proportion of non-fragilis Bacteroides species increased. More than 90% of the isolates tested were susceptible to piperacillin-tazobactam, meropenem, and tigecycline. Significantly lower susceptibility rates to cefoxitin (p<0.001), clindamycin (p<0.001), piperacillin/tazobactam (p<0.001), and tigecycline (p = 0.006) were observed among non-fragilis Bacteroides species isolates than among B. fragilis isolates. Moreover, the susceptibility rates to clindamycin (p = 0.003) and tigecycline (p = 0.044) decreased significantly among non-fragilis Bacteroides species over time. Clindamycin susceptibility rates higher than 80% were found in Greece (100%), Sweden (86.3%), and the United Kingdom (80.7%), and the lowest susceptibility rates were found in the United States (42.9%) and Japan (53.9%). In conclusion, the susceptibility of Bacteroides species to commonly used antibiotics varied geographically. Empirical antibiotic therapy for suspected anaerobic infections with clindamycin and cefoxitin should be avoided due to high resistance rates. Piperacillin-tazobactam, meropenem, metronidazole, and tigecycline could be considered favourable options for the treatment of infections caused by Bacteroides species.

Differences between bloodstream infections involving Gram-positive and Gram-negative anaerobes

BackgroundThe objectives of this study were to describe differences between bloodstream infections involving Gram-positive (GP) and Gram-negative (GN) anaerobic bacteria. MethodsPatients with clinically significant anaerobic bacteremia detected between October 2016 and July 2022 in a tertiary hospital in Granada (Spain) were retrospectively included. Species identification was performed by MALDI-TOF MS and/or molecular methods. The association between variables was analyzed using contingency tables, applying the chi-square test when expected frequencies were adequate and the Fisher exact test when not. Variables were gathered at the time of the first positive blood culture. ResultsOut of 237 cases of anaerobic bloodstream infections detected, 127 (53.6%) were GN. Crude mortality was 20.3%, corresponding to 48 patients who died of causes directly attributable to bacteremia. The presence of malignant disease (p = 0.011), abdominal and/or pelvic surgery (p = 0.001), and transplantation (p = 0.008) were significantly associated with bacteremia due to GN bacteria, while the presence of diabetes mellitus was significantly associated with bacteremia due to GP bacteria (p = 0.022). The presence of both septic shock and mortality was more frequently associated with bacteremia due to GN versus GP bacteria. ConclusionsThe association of certain variables with the presence of bloodstream infections due to GP or GN anaerobic bacteria may assist in selecting the optimal empirical therapeutic approach and improving the outcome of patients with these types of infection.

Community-onset anaerobic bloodstream infection, predisposing factors, and impact on survival: A prospective cohort study

BackgroundFew studies have examined the outcomes and predisposing risk factors for anaerobic bloodstream infections (BSIs). ObjectiveTo determine the survival impact of aerobic versus anaerobic BSI, a prospective cohort study was conducted. MethodsWe prospectively enrolled emergency department patients at a tertiary medical center with BSIs determined by laboratory testing between 2015 and 2016. Anaerobic and aerobic BSIs were compared for demographics, comorbidities, and sources of infection. Several independent risk factors were identified in a multivariable logistic regression model. Using propensity score (PS) matched data, an analysis of survival effects associated with anaerobic BSI has been conducted. ResultsOver a 2-year period, there were 1,166 episodes of BSI, of which 61 (5.2%) occurred as anaerobic episodes. Anaerobic BSIs were strongly associated with intra-abdominal infection (odds ratio [OR] 6.03, 95%CI 2.78–13.09), liver abscess (OR 3.92, 95%CI 1.47–10.45), skin and soft-tissue infection (OR 2.65, 95%CI 1.26–5.62), and metastatic cancer (OR 2.40, 95%CI 1.13–5.08) as the main positive predictors. Negative predictors included diabetes mellitus (OR 0.38, 95%CI 0.18–0.78), thrombocytopenia (OR 0.33, 95%CI 0.18–0.60), and urinary tract infection (OR 0.15, 95%CI 0.04–0.62). Anaerobic BSIs were not associated with worse prognosis after PS-matched analysis (hazard ratio [HR] 1.40, 95%CI 0.44–4.41) in our cohort. ConclusionsA significant percentage of community-onset BSI was due to anaerobic BSI. Anaerobic BSI can have a detrimental outcome if there are underlying comorbidities, high-risk infection sites, and inappropriate antibiotic choices. The findings of our study may contribute to the prescription of empiric anti-anaerobe antibiotics.

Population pharmacokinetics of levornidazole in healthy subjects and patients and sequential dosing regimen proposal using pharmacokinetic/pharmacodynamic analysis.

Although levornidazole sequential treatment has been used for anaerobic infection in clinical practice, there is no evidence-based dosing regimen. This study aimed to evaluate the pharmacokinetics (PK) of levornidazole in healthy subjects and patients and to propose an evidence-based sequential dosing regimen by pharmacokinetic/pharmacodynamic (PK/PD) analysis. Population PK model was built using the data of 116 Chinese subjects, including 88 healthy young subjects, 12 healthy elderly subjects, and 16 patients with intra-abdominal anaerobic infection. PK/PD analysis was performed combining the minimuminhibitoryconcentrations (MICs) of levornidazole against 375 anaerobic strains. Four sequential dosing regimens (500 mg q12h, 1000 mg loading dose followed by 500 mg q12h, 750 mg q24h, and 1000 mg q24h) were evaluated in terms of cumulative fraction of response (CFR) and probability of target attainment (PTA) by Monte Carlo simulation. The concentration data of levornidazole and its active metabolites were adequately described by two- and one-compartment model, respectively. Body weight was identified as a significant covariate of levornidazole clearance. Simulations showed that satisfactory PTA (> 90%) was achieved for the four dosing regimens when MIC ≤ 1 mg/L. Considering simulation results, patients' safety and compliance, levornidazole 750 mg IV infusion q24h for 2 days followed by oral dose of 750 mg q24h for 5 days was optimal for Bacteroides spp. with an identified MIC ≤ 1 mg/L.

Proteomic analysis of metronidazole resistance in the human facultative pathogen Bacteroides fragilis.

The anaerobic gut bacteria and opportunistic pathogen Bacteroides fragilis can cause life-threatening infections when leaving its niche and reaching body sites outside of the gut. The antimicrobial metronidazole is a mainstay in the treatment of anaerobic infections and also highly effective against Bacteroides spp. Although resistance rates have remained low in general, metronidazole resistance does occur in B. fragilis and can favor fatal disease outcomes. Most metronidazole-resistant Bacteroides isolates harbor nim genes, commonly believed to encode for nitroreductases which deactivate metronidazole. Recent research, however, suggests that the mode of resistance mediated by Nim proteins might be more complex than anticipated because they affect the cellular metabolism, e.g., by increasing the activity of pyruvate:ferredoxin oxidoreductase (PFOR). Moreover, although nim genes confer only low-level metronidazole resistance to Bacteroides, high-level resistance can be much easier induced in the laboratory in the presence of a nim gene than without. Due to these observations, we hypothesized that nim genes might induce changes in the B. fragilis proteome and performed comparative mass-spectrometric analyses with B. fragilis 638R, either with or without the nimA gene. Further, we compared protein expression profiles in both strains after induction of high-level metronidazole resistance. Interestingly, only few proteins were repeatedly found to be differentially expressed in strain 638R with the nimA gene, one of them being the flavodiiron protein FprA, an enzyme involved in oxygen scavenging. After induction of metronidazole resistance, a far higher number of proteins were found to be differentially expressed in 638R without nimA than in 638R with nimA. In the former, factors for the import of hemin were strongly downregulated, indicating impaired iron import, whereas in the latter, the observed changes were not only less numerous but also less specific. Both resistant strains, however, displayed a reduced capability of scavenging oxygen. Susceptibility to metronidazole could be widely restored in resistant 638R without nimA by supplementing growth media with ferrous iron sulfate, but not so in resistant 638R with the nimA gene. Finally, based on the results of this study, we present a novel hypothetic model of metronidazole resistance and NimA function.

Phenotyping empyema by pleural fluid culture results and macroscopic appearance: an 8-year retrospective study.

The clinical impact of phenotyping empyema is poorly described. This study was designed to evaluate clinical characteristics and outcomes based on the two readily available parameters, pleural fluid culture status and macroscopic fluid appearance. A retrospective study was conducted on patients with empyema hospitalised between 2013 and 2020. Empyema was classified into culture-positive empyema (CPE) or culture-negative empyema (CNE) and pus-appearing empyema (PAE) or non-pus-appearing empyema (non-PAE) based on the pleural fluid culture status and macroscopic fluid appearance, respectively. Altogether, 212 patients had confirmed empyema (CPE: n=188, CNE: n=24; PAE: n=118, non-PAE: n=94). The cohort was predominantly male (n=163, 76.9%) with a mean age of 65.0±13.6 years. Most patients (n=180, 84.9%) had at least one comorbidity. Patients with CPE had higher rates of in-hospital mortality (19.1% versus 0.0%, p=0.017) and 90-day mortality (18.6% versus 0.0%, p=0.017) and more extrapulmonary sources of infection (29.8% versus 8.3%, p=0.026) when compared with patients with CNE. No significant difference in mortality rate was found between PAE and non-PAE during the in-hospital stay and at 30 days and 90 days. Patients with PAE had less extrapulmonary sources of infection (20.3% versus 36.2%, p=0.010) and more anaerobic infection (40.9% versus 24.5%, p=0.017) than those with non-PAE. The median RAPID (renal, age, purulence, infection source, and dietary factors) scores were higher in the CPE and non-PAE groups. After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis. Empyema is a heterogeneous disease with different clinical characteristics. Phenotyping empyema into different subclasses based on pleural fluid microbiological results and macroscopic fluid appearance provides insight into the underlying bacteriology, source of infection and subsequent clinical outcomes.

Case series of Anaerococcus prevotii infection in road traffic accidents in New Delhi, India

ABSTRACT Anaerobic bacteria are part of the normal human skin flora. However, anaerobic infections could have different clinical courses with outcomes ranging from local abscesses to life-threatening conditions. Any long-term wound infection or a wound discharging pus with a foul smell is an indication of anaerobic infections. We present here a series of three cases of infection in patients injured in road traffic accidents (RTA) in which Anaerococcus prevotii was identified as the pathogen. Samples isolated from tissues of patients from three different RTAs were received in anaerobic conditions in Robertson Cooked Meat medium (RCM) within 2-4 h of collection. RCM was incubated for 24 h and then inoculated on three blood agars (BA) plates cultured anaerobically in a Gas Pack Jar, in a CO2 incubator, or aerobically. No growth was noted on the aerobically incubated plate. After 48 h, anaerobic plates were examined for growth and a Gram stain was performed. The identity of isolated colonies was confirmed by VITEK-2, and sensitivity testing was done by the pour plate method using Epsilon meter strips. All three tissue samples isolated from (1) the right leg, (2) the right inguinal region, and (3) the left thigh of patients revealed Anaerococcus prevotii, and two isolates showed resistance to the antibiotic metronidazole. Any injury with long-term infection, especially in patients suffered from RTAs, needs to be scrutinized for anaerobic infections since they are common in RTA related injuries. No random medication should be administered without prior culture sensitivity testing, because it might contribute to metronidazole or other antibiotics resistance.

Composting: A biosecurity measure to maximize the benefit of broilers̕ litter.

This study was conducted to evaluate the effect of composting on the count of Salmonella spp., Clostridium perfringens, and New Castle virus (NDV) isolated from broilers' litter. Moreover, to verify the impact of compost thermal stress on the expression of thermal genes harbored in the isolated bacteria. The prevalence of enteric aerobic and anaerobic infections by Salmonella spp., C. perfringens, and viral infections by NDV were investigated in litter samples collected from 100 broiler flocks by conventional methods and polymerase chain reaction. The samples were positive for Salmonella spp., C. perfringens, and NDV, with prevalence rates of 60%, 55%, and 30%, respectively. An experiment to study the effect of compost on the microbiological quality of litter was applied using five compost heaps with an initial average count of Salmonella typhimurium (3.2 × 105CFU CFU/gm), C. perfringens (6.4 × 105 CFU/gm), and an average titer NDV (105.5 embryo infectious dose50/gm). The microbiological count of heaps after 15 days of composting revealed a reduction in the count of S. typhimurium and C. perfringens by 4 log10 CFU/gm and 3 log10 CFU/gm, respectively. Moreover, the hemagglutinating test revealed no detection of NDV after 15 days of composting. A high degree of downregulation of expression of the thermal genes, dnaK in S. typhimurium isolates and cpe gene in C. perfringens isolates, was detected by quantitative reverse transcription PCR. The reduction of pathogen counts, the simplicity, and the low cost associated with composting for only 15 days advocate the recommendation for raising awareness of composting as a routine biosecurity measure to prevent the spreading of infection and promote its safe use in agribusiness.

A case report of metronidazole-induced encephalopathy in a bowel obstruction patient with MRI findings

Metronidazole is a widely used antimicrobial agent in the treatment of anaerobic and protozoal infections. However, excessive and prolonged use of metronidazole can lead to encephalopathy. We present a case of a 69-year-old male with bowel obstruction who was treated with metronidazole for approximately 26 days and subsequently developed neurological signs and symptoms. The magnetic resonance imaging findings were consistent with the suspected diagnosis of metronidazole-induced encephalopathy. This case highlights the necessity for careful monitoring of patients receiving metronidazole to detect central nervous system toxicity, and emphasizes the role of magnetic resonance imaging in confirming the diagnosis.

Use of Magnetic Nanoparticles to Isolate Anaerobic Bacteria

Objective: Anaerobic bacteria, which make up an important part of normal body flora, may lead to serious life-threatening infections. Since isolation and identification of anaerobic bacteria require time-consuming, sensitive, and difficult methods, they can only be performed in certain clinical laboratories. For this reason, diagnosis and treatment of anaerobic infections are delayed and drug resistance is observed due to empirical treatment. New methods that will enable the early identification of these bacteria will help reduce the duration of treatment and mortality rates due to anaerobic infections. Method: In this study, it is aimed to design magnetic nanoparticles attached to N-methyl-D-glucamine (Mag-NMDG) to catch anaerobic bacteria for rapid identification. Mag-NMDG nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), and vibrating sample magnetometer (VSM). Results: Mag-NMDG nanoparticles were applied to gram positive and gram negative anaerobic bacteria such as Actinomyces odontolyticus, Prevotella buccae, Veillonella parvula, Bifidobacterium dentium and Bacteroides fragilis isolated from culture media. The binding of bacteria to Mag-NMDG was determined by microscope images, McFarland values, and MALDI-TOF MS identification scores. Conclusion: As a result of this study, it was concluded that the Mag-NMDG nanoparticles could be used to isolate anaerobic bacteria directly from samples. Thus, it is foreseen that many time-consuming and troublesome steps in the isolation and identification stages can be eliminated.

Synthesis and Atimicrobial Evaluation of Deuterated Analogues of Metronidazole

The discovery of novel therapeutic molecules is always difficult, and there are a variety of methodologies that use the most diverse and innovative medicinal chemistry approaches. One such approach is the deuteration technique: Deuteration is the process of substituting deuterium for hydrogen in a molecule. When compared to the drug molecule, its deuterated analogues may retain the features of the original molecule and, in some cases, improve its pharmacological activity, with fewer side effects and lower toxicity. Metronidazole is a commonly used antibiotic to treat anaerobic bacterial infections, protozoal and microaerophilic bacterial infections. Metronidazole has a half-life of 6.5 ± 2.9 hours. A number of studies have recently been conducted on the selective substitution of hydrogen with deuterium. which increases the bond strength, increasing the biological half-life and, consequently, the drug's metabolic stability also increases. In an attempt to address metronidazole's drawbacks and clinical resistance, deuterated metronidazole was synthesised, characterised, and tested for antibacterial, antifungal, and anti-tubercular activities. The metronidazole and its deuterated compound showed equipotent antifungal activity and aerobic antibacterial activity. Also, when compared with the non-deuterated compound, deuterated metronidazole exhibited better anaerobic antibacterial and anti-tubercular activity.