Antimycoplasmal Activity Research Articles

Rapid Screening of Polyol Polyketides from Marine Dinoflagellates.

Dinoflagellate-derived polyketides are typically large molecules (>1000 Da) with complex structures, potent bioactivities, and high toxicities. Their discovery suffers three major bottlenecks: insufficient bioavailability, low-yield cultivation of producer organisms, and production of multiple highly related analogues by a single strain. Consequently, the biotechnological production of therapeutics or toxicological standards of dinoflagellate-derived polyketides is also hampered. Strategies based on sensitive and selective techniques for chemical prospection of dinoflagellate extracts could aid in overcoming these limitations, as it allows selecting the most interesting candidates for discovery and exploitation programs according to the biosynthetic potential. In this work, we assess the combination of data-dependent liquid chromatography coupled with high-resolution tandem mass spectrometry (LC–HRMS2) and molecular networking to screen polyol polyketides. To demonstrate the power of this approach, we selected dinoflagellate Amphidinium carterae since it is commonly used as a biotechnological model and produces amphidinols, a family of polyol-polyene compounds with antifungal and antimycoplasmal activity. First, we screened families of compounds with multiple hydroxyl groups by examining MS2 profiles that contain sequential neutral losses of water. Then, we clustered MS2 spectra by molecular networking to facilitate the dereplication and discovery of amphidinols. Finally, we used the MS2 fragmentation behavior of well-characterized luteophanol D as a model to propose a structural hypothesis of nine novel amphidinols. We envision that this strategy is a valuable approach to rapidly monitoring toxin production of known and unknown polyol polyketides in dinoflagellates, even in small culture volumes, and distinguishing strains according to their toxin profiles.

Pharmacokinetic and Pharmacodynamic integration of tilmicosin against Mycoplasma gallisepticum in the target infection site in chickens.

Mycoplasma gallisepticum (M. gallisepticum) is a primary respiratory pathogen of poultry and causes significant economic losses to the poultry industry. There were no reported articles concerning the Pharmacokinetics/Pharmacodynamics (PK/PD) interactions of tilmicosin against M. gallisepticum in vivo. In the current study, we established an in vivo M. gallisepticum infection model and tilmicosin was administered orally to the M. gallisepticum-infected chickens by different dosage regimens. The concentration of tilmicosin in lung tissue was determined by high-pressure liquid chromatography/tandem mass spectrometry (HPLC–MS/MS), besides the counting of the viable colony of M. gallisepticum in lung tissue was also monitored dynamically to appraise the PK/PD interactions of tilmicosin against M. gallisepticum. We found that anti-mycoplasmal activity was concentration-dependent and mycoplasmacidal activity was observed at tilmicosin dosage >7.5 mg/kg. The PK/PD parameter of AUC/MIC (The area under the concentration–time curve divided by the minimal inhibitory concentration) correlated well with anti-mycoplasmal efficacy (R2 = 0.92). The ratios of AUC/MIC for 1 log10 and 3 log10 colony-forming units [CFU]/lung reductions were 300.02 and 6,950.15 h, respectively. These findings indicated that tilmicosin may be therapeutically effective in chickens to treat M. gallisepticum lung infections if administered at a dose of 9.12 mg/kg.

Natural Polyether Ionophores and Their Pharmacological Profile.

This review is devoted to the study of the biological activity of polyether ionophores produced by bacteria, unicellular marine algae, red seaweeds, marine sponges, and coelenterates. Biological activities have been studied experimentally in various laboratories, as well as data obtained using QSAR (Quantitative Structure–Activity Relationships) algorithms. According to the data obtained, it was shown that polyether toxins exhibit strong antibacterial, antimicrobial, antifungal, antitumor, and other activities. Along with this, it was found that natural polyether ionophores exhibit such properties as antiparasitic, antiprotozoal, cytostatic, anti-mycoplasmal, and antieczema activities. In addition, polyethers have been found to be potential regulators of lipid metabolism or inhibitors of DNA synthesis. Further study of the mechanisms of action and the search for new polyether ionophores and their derivatives may provide more effective therapeutic natural polyether ionophores for the treatment of cancer and other diseases. For some polyether ionophores, 3D graphs are presented, which demonstrate the predicted and calculated activities. The data presented in this review will be of interest to pharmacologists, chemists, practical medicine, and the pharmaceutical industry.

Rapid Confirmatory Method for the Determination of Danofloxacin and N-Desmethyl Danofloxacin in European Seabass by UPLC-PDA

Background: Danofloxacin is a synthetic antibacterial agent with broad spectrum antibacterial and antimycoplasmal activity which is widely used in aquaculture. Methods: A UPLC (Ultra Performance Liquid Chromatography) method was developed and validated for the determination of danofloxacin (Dano) and its major metabolite N-desmethyl danofloxacin (Ndesmethyl Dano) in muscle plus skin tissue of European seabass (Dicentrarchus labrax) for the first time. For the separation an analytical column UPLC BEH C18 2.1 × 5 mm (1.7 µm) was used with an isocratic mobile phase consisting of MeOH-water acidified with formic acid (0.01%) (18:82; v/v) and flow rate of 0.3 mL/min within 5.5 min. The detection was performed at 275 nm using a photodiode array detector for both compounds. Examined fluoroquinolones were isolated from seabass muscle and skin tissue by extraction with acidic ACN and further purification with the QuEChERS methodology. Results: Recovery rates from muscle and skin tissue ranged between 90.2 and 101.2% for both compounds. The detection limit of the method was estimated at 13.73 µg/kg for Dano, 18.32 µg/kg for Ndesmethyl Dano, while the limits of quantification were 41.62 and 55.52 µg/kg, respectively. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity according to the European Union Decision 2002/657/EC. Conclusion: The new developed and validated method can be readily applied to aqua cultured fish after dietary administration of danofloxacin. Keywords: Danofloxacin, metabolite, fish, seabass, residue analysis, QuEChERS, UPLC-PDA.

Antimycoplasmal Activities of Compounds from Solanum aculeastrum and Piliostigma thonningii against Strains from the Mycoplasma mycoides Cluster.

Infections caused by Mycoplasma species belonging to the ‘mycoides cluster’ negatively affect the agricultural sector through losses in livestock productivity. These Mycoplasma strains are resistant to many conventional antibiotics due to the total lack of cell wall. Therefore, there is an urgent need to develop new antimicrobial agents from alternative sources such as medicinal plants to curb the resistance threat. Recent studies on extracts from Solanum aculeastrum and Piliostigma thonningii revealed interesting antimycoplasmal activities hence the motivation to investigate the antimycoplasmal activities of constituent compounds. The CH2Cl2/MeOH extracts from the berries of S. aculeastrum yielded a new β-sitosterol derivative (1) along with six known ones including; lupeol (2), two long-chain fatty alcohols namely undecyl alcohol (3) and lauryl alcohol (4); two long-chain fatty acids namely; myristic acid (5) and nervonic acid (6) as well as a glycosidic steroidal alkaloid; (25R)-3β-O-α-L-rhamnopyranosyl-(1→2)-O-[α-L-rhamnopyranosyl-(1→4)]-β-D-glucopyranosyloxy-22α-N-spirosol-5-ene (7) from the MeOH extracts. A new furan diglycoside, (2,5-D-diglucopyranosyloxy-furan) (8) was also characterized from the CH2Cl2/MeOH extract of stem bark of P. thonningii. The structures of the compounds were determined on the basis of spectroscopic evidence and comparison with literature data. Compounds 1, 3, 4, 7, and 8 isolated in sufficient yields were tested against the growth of two Mycoplasma mycoides subsp. mycoides (Mmm), two M. mycoides. capri (Mmc), and one M. capricolum capricolum (Mcc) using broth dilution methods, while the minimum inhibitory concentration (MIC) was determined by serial dilution. The inhibition of Mycoplasma in vitro growth was determined by the use of both flow cytometry (FCM) and color change units (CCU) methods. Compounds 4 and 7 showed moderate activity against the growth of Mmm and Mmc but were inactive against the growth of Mcc. The lowest MIC value was 50 μg/ml for compound 7 against Mmm. The rest of the compounds showed minimal or no activity against the strains of Mycoplasma mycoides tested. This is the first report on the use of combined FCM and CCU to determine inhibition of in vitro growth of Mycoplasma mycoides. The activity of these compounds against other bacterial strains should be tested and their safety profiles determined.

Selected ethno-medicinal plants from Kenya with in vitro activity against major African livestock pathogens belonging to the “Mycoplasma mycoides cluster”

Ethnopharmocological relevanceMembers of ‘Mycoplasma mycoides cluster’ are important ruminant pathogens in Africa. Diseases caused by these Mycoplasma negatively affect the agricultural sector especially in developing countries through losses in livestock productivity, mortality and international trade restrictions. There is therefore urgent need to develop antimicrobials from alternative sources such as medicinal plants to curb these diseases. In Kenya, smallholder farmers belonging to the Maasai, Kuria and Luo rely on traditional Kenyan herbals to treat respiratory symptoms in ruminants. In the current study extracts from some of these plants were tested against the growth of members of Mycoplasma mycoides cluster. AimThis study aimed at identifying plants that exhibit antimycoplasmal activities using an ethnobotanical approach. Materials and methodsKenyan farmers of Maasai, Luo and Kuria ethnic groups were interviewed for plant remedies given to livestock with respiratory syndromes. The plant materials were thereafter collected and crude extracts prepared using a mixture of 50% of methanol (MeOH) in dichloromethane (CH2Cl2), neat methanol (MeOH), ethanol (EtOH) and water to yield four crude extracts per plant part. The extracts were tested in vitro against five strains of Mycoplasma mycoides subsp. capri, five strains of Mycoplasma mycoides subsp. mycoides and one strain of Mycoplasma capricolum subsp capricolum using broth micro-dilution assays with an initial concentration of 1mg/ml. Minimum inhibitory concentration (MIC) of the most active extracts were determined by serial dilution. ResultsExtracts from five plants namely: Solanum aculeastrum, Albizia coriaria, Ekebergia capensis, Piliostigma thonningii and Euclea divinorum exhibited the highest activities against the Mycoplasma strains tested. Mycoplasma mycoides subsp. mycoides were more susceptible to these extracts than Mycoplasma mycoides subsp. capri and Mycoplasma capricolum susp. capricolum. The activities of the crude extracts varied with the solvent used for extraction. The MICs mean values of the active extracts varied from 0.02 to 0.6mg/ml. ConclusionsThe results suggested that these plants could potentially contain antimicrobial compounds that might be useful for the treatment of respiratory diseases in ruminants. Future work should focus on the isolation and identification of the active compounds from the plant extracts that showed interesting activities and evaluation of their antimicrobial and cytotoxic potential.

Effects of Traditional Chinese Medicine Qinbai Qingfei Concentrated Pellet on Cellular Infectivity of Mycoplasma pneumoniae

Aim. To study the effect and mechanism of traditional Chinese medicine Qinbai Qingfei concentrated pellet (QQCP) against Mycoplasma pneumoniae (MP). Methods. Rat airway smooth muscle (ASM) cells were used to examine the antimycoplasmal activity of QQCP via four drug-adding modes: pre- and postadding drugs, simultaneous-adding after drug and MP mixed, and simultaneous-adding drug and MP; taking roxithromycin dispersive tablets (RDT) as positive control, the cellular A 570 values were determined by MTT method. Results. All of A 570 values in QQCP group were significantly higher than those of the corresponding MP control group (P < 0.01) in four drug-adding modes; there was no significant difference in A 570 values between the QQCP group and that of the positive control group (P > 0.05), confirming that QQCP could significantly inhibit the infectivity of MP to ASM cells. Conclusion. QQCP had significant activity in preventing and treating MP infection, killing MP, and antiabsorption.

Clinical features, risk factors and treatment of fulminant Mycoplasma pneumoniae pneumonia: A review of the Japanese literature

Mycoplasma pneumoniae (MP) is one of the most common causes of community-acquired pneumonia in children and young adults. Although MP sometimes causes self-limiting pneumonia, severe and fulminant cases with hypoxia occur, but their clinical features have rarely been reported. This study aimed to reveal the clinical manifestations, risk factors, and treatment of fulminant MP pneumonia (MPP). Using PubMed and abstracts from the proceedings of several domestic Japanese academic societies, we reviewed the Japanese and English literature for cases of fulminant or severe MPP reported in Japan. All clinical information such as sex, age, underlying diseases, clinical symptoms, clinical course, laboratory and radiological findings, and treatment was collected and analyzed. In total, 52 fulminant MPP cases were reported between September, 1979 and February, 2010. The dominant population of fulminant MPP was young adults without severe underlying diseases. Cough (97.3%), fever (100.0%), and dyspnea (83.3%) with diffuse abnormal findings in radiological examinations were noted. Antibiotics without anti-mycoplasmal activity were used in 32 cases (61.5%) as initial treatment prior to the onset of hypoxia. Anti-mycoplasmal drugs were appropriately used in 41 cases (78.8%) after onset of respiratory failure with steroids (23 cases, 45.1%) and effective. The majority of patients improved within 3-5 days after steroid administration. There were only 2 fatal cases. Although this small retrospective study did not reveal the apparent risk factors of fulminant MPP, initial inappropriate use of antibiotics may be a risk factor, and early administration of appropriate anti-mycoplasmal drugs with steroids as a cellular immune suppressor is required.

In vitro antimicrobial activities of cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene against Mycoplasma hominis clinical isolates

The aim of this study was to evaluate the antimicrobial effects of five natural substances against 50 clinical isolates of Mycoplasma hominis. The in vitro activity of selected natural compounds, cinnamon bark oil, anethole, carvacrol, eugenol and guaiazulene, was investigated against 50 M. hominis isolates cultivated from cervical swabs by the broth dilution method. All showed valuable antimicrobial activity against the tested isolates. Oil from the bark of Cinnamomum zeylanicum (MBC90 = 500 µg/mL) however was found to be the most effective. Carvacrol (MBC90 = 600 µg/mL) and eugenol (MBC90 = 1000 µg/mL) also possessed strong antimycoplasmal activity. The results indicate that cinnamon bark oil, carvacrol and eugenol have strong antimycoplasmal activity and the potential for use as antimicrobial agents in the treatment of mycoplasmal infections.

Inhibitory activity of garenoxacin against DNA gyrase of Mycoplasma pneumoniae

Garenoxacin, a des-fluoro(6)-quinolone, exhibits potent activity against Mycoplasma pneumoniae, including macrolide-resistant strains. There has been no report on the inhibitory activity of garenoxacin against the target enzyme of M. pneumoniae. Subunits of DNA gyrase (GyrA and GyrB) proteins of M. pneumoniae FH were separately expressed as His-tagged proteins in Escherichia coli Chaperone Competent Cell BL21 by IPTG induction of plasmids containing the respective gyrA and gyrB genes. The inhibitory activities of garenoxacin, moxifloxacin, gatifloxacin and levofloxacin against DNA gyrase were evaluated by the inhibition of supercoiling activity (n = 3). Against M. pneumoniae FH, garenoxacin showed 2- to 16-fold more potent activity than the other quinolones. The mean IC(50) of garenoxacin for DNA gyrase of M. pneumoniae was 2.5 mg/L. Garenoxacin showed the most potent inhibitory activity against M. pneumoniae DNA gyrase among the quinolones tested. The IC(50) values of the quinolones for DNA gyrase roughly correlated with each MIC value. The antimycoplasmal activity of the quinolones was almost certainly due to inhibition of the supercoiling activity of DNA gyrase. Garenoxacin was considered a valuable quinolone in the treatment of infectious diseases caused by M. pneumoniae.

In vitro antimycoplasmal activity of citrus bergamia essential oil and its major components

Forty-two strains of Mycoplasma hominis (including PG21), 2 strain of Mycoplasma fermentans (Pg18 and K7), 1 strain of Mycoplasma pneumoniae (strain m129) were investigated for their susceptibilities to Citrus bergamia essential oil and to its major components (limonene, linalyl acetate and linalool). C. bergamia essential oil inhibited mycoplasmas at concentrations from 0.5 to 1% (MIC value as % v/v). M. hominis showed MIC50 values of 0.5% and MIC90 values of 1%; M. pneumoniae showed a MIC value of 0.5% while M. fermentans strains were inhibited by MIC values of 1%. M. pneumoniae and M. hominis shared the same susceptibility to linalyl acetate, with MIC values of 0.015% (corresponding to MIC50 and MIC90 for M. hominis); M. fermentans strains were less susceptible with MIC values of 0.12%. Among the major components tested, linalool showed higher activity against M. pneumoniae and M. fermentans (MIC values of 0.015 and 0.06%, respectively) but was less active against M. hominis (MIC50 and MIC90 values of both 1%); limonene was active against M. pneumoniae (MIC value of 0.03%) but was less active against M. fermentans (MIC values of 1%) and M. hominis (both MIC50 and MIC90 values of ≥4%). The results indicated that C. bergamia essential oil and its major components had shown an interesting in vitro antimycoplasmal activity.

In-vitro Antimycoplasmal Activity of Triclosan in Combination with Fluoroquinolones against Five mycoplasma Species.

Mycoplasmosis caused by mycoplasma has immensely reduced the performance of commercial animal husbandry, along with prevalence and increase of drug resistance in mycoplasma, thus new agents and therapies are urgently needed. Triclosan is a broad spectrum antimicrobial agent with a favorable safety profile. In the present study, we tested the antimycoplasmal activity of triclosan alone, as well as the in-vitro interaction of triclosan and the fluoroquinolones, gatifloxacin (GAT), moxifloxacin (MXF), levofloxacin (LVX), sparfloxacin (SPX), ciprofloxacin (CIP), enrofloxacin (EFX), and norfloxacin (NOR), against five mycoplasma species. This study demonstrated that triclosan had antimycoplasmal activity against both fluoroquinolones-sensitive species and a fluoroquinolones-resistant species isolated from clinic, with minimum inhibitory concentrations (MICs) of 16.0-64.0 μg/mL and 64.0 μg/ mL, respectively. A synergistic antimycoplasmal effect between triclosan and GAT, MFX or EFX against the five mycoplasma species was observed, with modulation factors (MFs) of 4-8, 4-16, 8-32, respectively, and fractional inhibitory concentration indexes (FICIs) of 0.375- 0.500, 0.350-0.500, 0.281-0.375, respectively. The combination of triclosan with LVX, SPX, CIP or NOR displayed either synergistic activity or indifference against the same mycoplasma species with MFs of 2-64, 4-16, 2-16, 2-64, respectively, while FICI values range from 0.516- 0.750, 0.500-0.625, 0.306-0.750, and 0.615-0.750, respectively. No antagonism was observed for any drug combination against any of the species tested. To the best of our knowledge, this is the first report that triclosan has synergistic activity with fluoroquinolones against mycoplasma species.

In Vitro Activities of 11 Antimicrobial Agents against Macrolide-Resistant Mycoplasma pneumoniae Isolates from Pediatric Patients: Results from a Multicenter Surveillance Study

Macrolide-resistant Mycoplasma pneumoniae is emerging in several countries, and it is mainly observed in children. To our knowledge, we conducted the first multicenter prospective epidemiological study of macrolide-resistant M. pneumoniae in order to investigate regional differences in the susceptibility of macrolide-resistant M. pneumoniae to antibacterial agents. The in vitro activities of 11 antimicrobial agents against macrolide-resistant M. pneumoniae isolates from 5 different areas of Japan were investigated. Among 190 M. pneumoniae isolates from pediatric patients, 124 (65.2%) isolates showed macrolide resistance and possessed an A2063G transition in domain V of the 23S rRNA. These isolates showed high resistance to erythromycin, clarithromycin, and azithromycin with minimum inhibitory concentrations (MICs) ≥ 16 μg/ml. Conversely, quinolones such as garenoxacin, moxifloxacin, tosufloxacin, and levofloxacin exhibited potent antimycoplasmal activity. No regional differences were observed with respect to the MICs among the 5 areas in Japan.

Antimycoplasmal activity of some plant species from northern Nigeria compared to the currently used therapeutic agent

Context: Mycoplasma spp. are obligate parasites of humans and animals. But due to the special requirements needed to culture Mycoplasma in the laboratory, little or no research has been done to evaluate the efficacy of medicinal plants on the organism.Objective: To screen medicinal plants traditionally used to treat infections for possible antimycoplasmal and cytotoxic activities.Materials and methods: Acetone extracts of 21 Nigerian medicinal plants were analyzed for antimycoplasmal and cytotoxicity activities using the metabolic inhibition and colorimetric methods, respectively. The extract with the best antimycoplasmal activities was also analyzed for its phytochemical constituents using the desktop method.Results: Calotropis procera (Aiton) R.Br (Asclepiadaceae) extract had the best antimycoplasmal effect with a minimum inhibitory concentration (MIC) of 80 µg/mL and minimum mycoplasmacidal concentration (MMC) of 160 µg/mL. This extract contained saponins, tannins, cardiac glycosides, alkaloids, and flavonoids. The extract of Vernonia amygdalina Delile (Compositae) was the most cytotoxic with median lethal concentration (LC50) of approximately 17 µg/mL, and that of Anacardium occidentale L. (Anacardiaceae) was the least cytotoxic with an LC50 of approximately 1919 µg/mL.Discussion: Calotropis procera is a promising plant for an alternative antimycoplasmal agent because the crude acetone extract had a higher mycoplasmacidal activity than the conventional drug tylosin, which is currently used in treatment of the disease in Nigeria.Conclusion: The crude extract of Calotropis procera is worth investigating for the development of a potent agent against cattle Mycoplasma, which has long defied solution by conventional chemotherapy.

Effects of geographical location on the yield and bioactivity of &lt;i&gt;Anoigeissus leiocarpus&lt;/i&gt;

Acetone extracts of the leaves of Anoigeissus leiocarpus collected from two different geographical locations from Nigeria were analysed for their phytochemicals, antioxidants, antibacterial, antimycoplasmal and cytotoxic activities. It was shown that plant from the colder region has higher yield and better activities than that from warmer region; having bacterial minimum inhibitory concentration (MIC) value of 0.08 mg/ml and mycoplasmal MIC value of 0.16mg/ml. The result showed that there were variations between the two plant extracts in their activities such as antimicrobial, phytochemicals, antioxidants and cytotoxicity.Keywords: Anoigeissus leiocarpus; Antioxidant; Antibacterial; Antimycoplasmal; Cytotoxic

Development of a reproducible method to determine minimum inhibitory concentration (MIC) of plant extract against a slow-growing mycoplasmas organism

Mycoplasma species are fastidious bacteria that require a specialized medium for their growth, isolation and identification. There are no standardized tests to evaluate the in vitro susceptibility of mycoplasmas to medicinal plant extracts. A widely used in-broth, microtitre plate, minimum inhibitory concentration (MIC) assay was adapted and evaluated using acetone extracts of Anoigeissus leiocarpus on the isolates of Mycoplasma mycoides subsp. mycoides small colony variants (MmmSC). Several problems were encountered including the contamination of the medium by Bacillus species found in plants and the fact that the slow-growing mycoplasmas proved to be poor reducers of the indicator tetrazolium salt or resorcinol. We then examined a pH indicator-dependant technique to detect the acid production caused by the growth of the organism after glucose utilization from the broth medium. The method gives a clear cut-off point that was easy to read and interpret and was also reproducible. The MIC value for acetone extract of A. leiocarpus was 0.16 mg/ml. The development of this method now makes it possible to evaluate extracts of several plant species for antimycoplasmal activity.

In vitro antimycoplasmal activity of six Jordanian medicinal plants against three Mycoplasma species

The in vitro effect of six Jordanian traditional medicine plant methanolic extracts were tested against 32 isolates of Mycoplasma species; Mycoplasma mycoides subsp. mycoides LC (6), Mycoplasma capricolum subsp. capricolum (8) and M. putrefaciens (18), all isolated from either nasal swabs or milk, from sheep and goats in different regions in Jordan. All Mycoplasma species showed susceptibility to Artemisia herba-alba and Artemisia arborescens with MIC ranges from 3.125-12.5 mg/ml. Allium sativum and Punica grantum showed limited activity against some Mycoplasma isolates. Olea europea and Citrullus colocynthis showed no in vitro activity against any of the Mycoplasma species tested. Artemisia herba-alba and Artemisia arborescens may therefore be useful for the treatment of mycoplasma infections.

Antimycoplasmal activity of hydroxytyrosol.

The aim of this study was to investigate the in vitro antimycoplasmal activity of hydroxytyrosol. Twenty strains of Mycoplasma hominis, three strains of Mycoplasma fermentans, and one strain of Mycoplasma pneumoniae were used. For M. pneumoniae, M. hominis, and M. fermentans, the MICs were 0.5, 0.03 (for 90% of the strains tested), and 0.25 microg/ml, respectively.

Effectiveness of two fluoroquinolones for the treatment of chronic respiratory disease outbreak in broilers

1. Chronic respiratory disease (CRD) caused by Mycoplasma synoviae in association with Escherichia coli is the disease most frequently encountered in poultry in Mexico. 2. Differences of antimycoplasmal activity, pharmacokinetics and cost among fluoroquinolones were the impetus for this clinical evaluation of efficacy of enrofloxacin and norfloxacin-nicotinate in broilers with CRD. 3. A total of 99,600 broilers, naturally infected with M. synoviae and E. coli , were treated with enrofloxacin (10 mg/kg/d for 3 d) (n = 49,800) or norfloxacin-nicotinate (20 mg/kg/d for 3 d) (n = 49,800). 4. Based on survivor analysis, there were no significant differences of efficacy of the 2 drugs. Survivor probabilities were above 0.99. 5. These results indicate that enrofloxacin and norfloxacin-nicotinate are efficacious for treatment of CRD. Questions remaining to be answered by other studies include: public health concern about the use of fluoroquinolones for the treatment of CRD; clinical superiority of one of these drugs on the basis of an attribute other than antimicrobial activity, such as cost:benefit ratio or ability to prevent bacterial resistance. 6. Clinical efficacy is not a relevant variable in assessing whether norfloxacin-nicotinate or enrofloxacin should be used for the treatment of CRD associated with E. coli in broilers.

In vitro antimycoplasmal activities of rufloxacin and its metabolite MF 922.

The in vitro activities of rufloxacin and its metabolite, MF 922, were compared with those of ofloxacin, ciprofloxacin, erythromycin, and minocycline against Mycoplasma pneumoniae, Mycoplasma hominis, Mycoplasma fermentans, and Ureaplasma urealyticum. Rufloxacin, MF 922, and ciprofloxacin shared similar activities against all mycoplasmas tested. (MICs for 90% of isolates tested [MIC90s], 0.5 to 4 micrograms/ml. Ofloxacin had the lowest MIC90s for U. urealyticum, M. fermentans, and M. hominis (MIC90s, 0.25 to 1 micrograms/ml) and erythromycin had the lowest MIC90 for M. pneumoniae (MIC90, 0.004 micrograms/ml).