Microbiological properties of tinidazole: spectrum, activity and ecological considerations

Effect of adding probiotics to an antibiotic intervention on the human gut microbial diversity and composition: a systematic review

Introduction. Millions of antibiotic prescriptions are written annually in the USA.

Gap Statement. Probiotics reduce antibiotic-induced gastrointestinal side effects; however, the effect of probiotics on preserving gut microbial composition in response to antibiotics is not well understood.

Aim. To evaluate whether the addition of probiotics is capable of reverting the changes in alpha diversity and gut microbial composition commonly observed in adult participants receiving antibiotics.

Methodology. A search was conducted by two researchers following the PRISMA guidelines using PubMed, Science Direct, Cochrane and Embase from January to December 2021 with the following inclusion criteria: (i) randomized clinical trials assessing the effect of antibiotics, probiotics or antibiotics+probiotics; (ii) 16S rRNA; (iii) adult participants; and (iv) in English. Once data was extracted in tables, a third researcher compared, evaluated and merged the collected data. The National Institutes of Health (NIH) rating system was utilized to analyse risk of bias.

Results. A total of 29 articles (n=11 antibiotics, n=11 probiotics and n=7 antibiotics+probiotics) met the inclusion criteria. The lack of standardization of protocols to analyse the gut microbial composition and the wide range of selected antibiotics/probiotics complicated data interpretation; however, despite these discrepancies, probiotic co-administration with antibiotics seemed to prevent some, but not all, of the gut microbial diversity and composition changes induced by antibiotics, including restoration of health-related bacteria such as Faecalibacterium prausnitzii .

Conclusion. Addition of probiotics to antibiotic interventions seems to preserve alpha diversity and ameliorate the changes to gut microbial composition caused by antibiotic interventions.

In Situ Reactivity of Electrochemically Generated Nitro Radical Anion on Tinidazole and Its Monomeric and Dimeric CuII Complexes on Model Biological Targets with Relative Manifestation of Preventing Bacterial Biofilm Formation

Formation of nitro radical anion (-NO₂ ^•-) and other reduction products of 5-nitroimidazoles, although important for antimicrobial activity, makes the drugs neurotoxic. Hence, an appropriate generation and their role in the free radical pathway needs proper realization. This was attempted by studying the action of tinidazole and its Cu^II complexes on model targets (nucleic acid bases and calf thymus DNA). Results obtained were correlated with studies on biological species where prevention of biofilm formation on Staphylococcus aureus and Pseudomonas aeruginosa was followed. Tinidazole and its Cu^II complexes subjected to electrochemical reduction in aqueous solution, under de-aerated conditions, interact with model nucleic acid bases and calf thymus DNA. These model targets were followed to realize what happens when such compounds undergo enzymatic reduction within cells of microorganisms that they eventually kill. Studies reveal that Cu^II complexes were better in modifying nucleic acid bases and calf thymus DNA than tinidazole; damage caused to nucleic acid bases was correlated with that caused to DNA, indicating that compounds affect DNA rich in thymine and adenine. Minimum bactericidal concentrations on sessile S. aureus and P. aeruginosa for the monomeric Cu^II complex were 12.5 and 20.25 μM respectively, while those for the dimeric complex were 40.0 and 45.0 μM, respectively. Biofilm formation by P. aeruginosa and S. aureus and viability count of sessile cells were also determined. Cu^II complexes of tinidazole brought about substantial reduction in carbohydrate and protein content in S. aureus and P. aeruginosa. Downregulation of quorum sensing signaling mechanism viz. reduced production of pyocyanin and elastase during biofilm formation was also detected. Cu^II complexes showed much higher tendency to prevent biofilm formation than tinidazole, almost comparable to amoxicillin, an established drug in this regard.

Comparative In Vitro Resistance of Human Periodontal Bacterial Pathogens to Tinidazole and Four Other Antibiotics

The in vitro resistance of selected red/orange complex periodontal pathogens to tinidazole was compared with four other antibiotics. Subgingival biofilm samples from 88 adults with severe periodontitis were anaerobically incubated on enriched Brucella blood agar with and without supplementation with tinidazole (16 mg/L), metronidazole (16 mg/L), amoxicillin (8 mg/L), doxycycline (4 mg/L), or clindamycin (4 mg/L). Growth of Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Parvimonas micra, Fusobacterium nucleatum, Streptococcus constellatus, or Campylobacter rectus on antibiotic-supplemented plates indicated their in vitro antibiotic resistance. Tinidazole inhibited all test species, except P. intermedia/nigrescens, P. micra, and S. constellatus in 3.8%, 10.2%, and 88.9% of species-positive patients, respectively. Significantly fewer patients yielded tinidazole-resistant test species, and had significantly lower subgingival proportions of tinidazole-resistant organisms, than patients with amoxicillin, doxycycline, or clindamycin-resistant species, but not those with metronidazole-resistant strains. Joint in vitro species resistance to tinidazole and amoxicillin, or metronidazole and amoxicillin, was rare. Tinidazole performed in vitro similar to metronidazole, and markedly better than amoxicillin, doxycycline, or clindamycin, against fresh clinical isolates of red/orange complex periodontal pathogens. As a result of its similar antimicrobial spectrum, and more convenient once-a-day oral dosing, tinidazole should be considered in place of metronidazole for systemic periodontitis drug therapy.

Formulation and evaluation of in situ forming PLA implant containing tinidazole for the treatment of periodontitis

Periodontitis is caused by periodontopathic bacteria and antibacterial agents are placed in a periodontal pocket with the intention of enhancing the local effect. To maximize the therapeutic effects while reducing the adverse effects, tinidazole was delivered by in situ forming system. One approach for reducing burst release rate was to testify in situ forming effect. The effect of 0%-10% (w/w) polyethylene glycol 400 and 3% (w/w) glycerol on the tinidazole release from a poly(DL-lactide) (PLA) injectable implant was evaluated. The results showed that the in vitro initial burst release rate was decreased in the presence of poly(ethyleneglycol) PEG 400 and glycerol. A formulation containing 30% (w/w) PLA (M(w) 7300) dissolved in 62% (w/w) N-methyl-2-pyrrolidone, 5% (w/w) PEG 400, and 3%(w/w) glycerol with 5% (w/w) tinidazole was shown to be optimum. Twelve adult beagle dogs were used in the periodontitis model. The treatment group I, II, and positive control group was administrated with gel containing 5%(w/w) tinidazole, 2.5%(w/w) tinidazole, and periocline, respectively. Dog studies revealed that periocline and the developed formulation could significantly decrease symptoms of periodontitis, and they were better than gel containing 2.5% (w/w) tinidazole. The developed formulation could sustain the release of tinidazole for local delivery over 7 days. These findings suggested that the developed formulation was a viable alternative to conventional drug to cure periodontitis.

In vitro activities of tinidazole and metronidazole against Clostridium difficile, Prevotella bivia and Bacteroides fragilis

Tinidazole, a 5-nitroimidazole similar to metronidazole, was studied against 40 Clostridium difficile, 10 Prevotella bivia and 11 Bacteroides fragilis clinical isolates. The geometric mean MICs of tinidazole and metronidazole were, respectively: C. difficile, 0.31 and 0.28 microg/mL; P. bivia, 2.33 and 1.52 microg/mL; B. fragilis, 0.5 and 0.71 microg/mL.

Increasing risk of relapse after treatment of Clostridium difficile colitis in Quebec, Canada

BACKGROUND

Clinicians who treat patients with Clostridium difficile-associated diarrhea (CDAD) in Quebec, Canada, have noted an apparent increase in the proportion of patients who experience relapse.

METHODS

To determine whether there was an increase in the frequency of treatment failure and of recurrence of CDAD after treatment, we reviewed data on cases that had been diagnosed in a hospital in the province of Quebec during the period 1991-2004. The frequency of recurrences within 60 days after the initial diagnosis was measured using Kaplan-Meier analysis, and Cox regression was used for multivariate analysis.

RESULTS

Among patients who had initially been treated with metronidazole, the proportion whose regimens were switched to vancomycin or for whom vancomycin was added because of a disappointing response did not vary between 1991 and 2002 (66 [9.6%] of 688 patients overall) but more than doubled in 2003-2004 (112 [25.7%] of 435; P < .001). Among 845 patients treated with metronidazole only, the 60-day probability of recurrence increased dramatically in 2003-2004 (47.2%), compared with 1991-2002 (20.8%; P < .001). During 1991-2002, the probabilities of recurrence were 20.0%, 13.8%, and 28.9% among individuals aged 0-17, 18-64, and > or = 65 years, respectively; during 2003-2004, the probabilities were 25.0%, 27.1%, and 58.4%, respectively.

CONCLUSION

In 2003-2004, there was an increase in the proportion of patients with CDAD believed, by their attending physicians, to have experienced metronidazole treatment failure, as well as an increase in the frequency of post-metronidazole therapy recurrences, especially among elderly persons.

Comparative activity of metronidazole and tinidazole against Clostridium difficile and Peptostreptococcus anaerobius

Broth dilution MICs of metronidazole against 38 strains of Clostridium difficile (0.13 microgram/ml) and 11 strains of Peptostreptococcus anaerobius (0.11 microgram/ml) were lower than those of tinidazole (0.16 and 0.17 microgram/ml, respectively). As molar concentrations the nitroimidazoles were equally active. The MICs of the two drugs correlated positively, and the relative activity of tinidazole increased with decreasing susceptibility of both species.

Comparative pharmacokinetics of metronidazole and tinidazole and their tissue penetration

Since metronidazole and tinidazole are used prophylactically against infections after colorectal surgery, their pharmacokinetics and that of hydroxy-metronidazole were compared in 34 such patients. Seventeen patients received a single dose of 1.5 g (50-min infusion) of either agent 1 h before the operation. The concentrations of serum and tissue homogenates (subcutaneous fat, omentum, peritoneum, ileum, appendix, colon) were assayed by high-pressure liquid chromatography. The serum concentrations 1 h after start of infusion were 34.1 +/- 6.7 mg/l of metronidazole, 2.3 +/- 1.2 mg/l of OH-metronidazole, and 35.2 +/- 6.3 mg/l of tinidazole. OH-metronidazole and tinidazole were detectable for 72 h and metronidazole for 48 h. The ranges of serum and tissue concentrations (subcutaneous fat, omentum, peritoneum, ileum, appendix, colon) overlapped (within one single standard deviation). The tissue concentrations were high, particularly in intestinal tissues, except that the levels were low in subcutaneous tissue. The serum half-life of metronidazole was 9.0 +/- 1.6 h, of OH-metronidazole 14.8 +/- 7.4 h, and of tinidazole 16.4 +/- 3.8 h. The terminal-phase distribution volume was 35.8 +/- 10.01 for metronidazole and 40.6 +/- 9.91 for tinidazole, and the total body clearance 2.7 +/- 1.2 l/h and 1.8 +/- 0.5 l/h, respectively. The slower disposition of OH-metronidazole, which inhibits anaerobic bacteria, prolongs the duration of bioactivity in the body after metronidazole to that reached by tinidazole. OH-tinidazole was not detected in patient specimens (assay standards ensured that it could be assayed).(ABSTRACT TRUNCATED AT 250 WORDS)

Single dose tinidazole prophylaxis in hysterectomy

The results of this randomized double blind, placebo controlled trial of a single oral dose of 2 g tinidazole or placebo approximately 12 hours before hysterectomy showed the incidence of infective morbidity in patients who received placebo was 12.2% compared with 1.9% in patients who received tinidazole, (p = 0.045). The mean serum concentration of tinidazole at the time of surgery was 35 mcg/ml, which was well in excess of the minimum concentration required to inhibit all of the 95 anaerobes isolated in this study. Serum tinidazole concentration remained adequately inhibitory for at least 24 hours after surgery. The ability of tinidazole prophylaxis to reduce further our already low rate of febrile morbidity was considered a worthwhile gain. It is now Unit policy to give this agent prophylactically to all patients if the integrity of the vagina is likely to be breached at the time of surgery.

A novel metabolite of tinidazole involving nitro-group migration

After oral doses to dogs of 14C-tinidazole, a 5-nitroimidazolyl antiprotozoal compound, a major and previously unidentified radioactive metabolite was isolated from urine and shown by FAB mass spectrometry and n.m.r. spectroscopy to be ring-hydroxylated. The exact identity of this metabolite was established by X-ray diffraction analysis as ethyl 2-(5-hydroxy-2-methyl-4-nitro-1-imidazolyl)ethyl sulphone. The apparent migration of the nitro group from the 5 position in the parent drug to the 4 position in the metabolite is a novel metabolic route.

Tinidazole--microbiology, pharmacology and efficacy in anaerobic infections

Tinidazole is a 5-nitroimidazole with selective activity against anaerobic bacteria and protozoa. It is bactericidal at low concentrations and its spectrum covers most anaerobic bacteria and some capnophilic microorganisms. Anaerobic bacteria known to be resistant to tinidazole include anaerobic streptococci, actinomyces and propionibacteria. Tinidazole is one of the most active antibacterial agents against Bacteroides fragilis which is one of the most resistant species of anaerobic bacteria. Only a few strains have been reported to be resistant. Tinidazole has been shown to be efficacious in protozoal infections such as trichomonal vaginitis, amoebiasis and giardiasis. Clinical studies have also shown that tinidazole is efficacious in the treatment of anaerobic infections including respiratory tract infections, intra-abdominal sepsis and obstetrical and gynecological infections. Since tinidazole has no activity against aerobic bacteria, it must be combined with other antibacterial agents in the treatment of mixed infections involving aerobic and anaerobic bacteria. Tinidazole has also been used successfully alone or in combination with other antimicrobial agents for prophylaxis in patients undergoing elective colonic and abdominal surgery, emergency appendectomy and gynecological surgery.