zithromax and Actinomycetales-Infections

Pneumonia caused by Rhodococcus equi remains an important cause of disease and death in foals. The combination of a macrolide (erythromycin, azithromycin, or clarithromycin) with rifampin remains the recommended therapy for foals with clinical signs of infection caused by R equi. Most foals with small, subclinical ultrasonographic pulmonary lesions associated with R equi recover without therapy, and administration of antimicrobial agents to these subclinically affected foals does not hasten lesion resolution relative to administration of a placebo. Resistance to macrolides and rifampin in isolates of R equi is increasing.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Clarithromycin; Drug Resistance, Multiple, Bacterial; Erythromycin; Horse Diseases; Horses; Pneumonia, Bacterial; Rhodococcus equi; Rifampin

To describe a case of severe sepsis, cavitary pneumonia, and pyomyositis caused by Arcanobacterium haemolyticum.. An 18-year-old male with a medical history significant for mild asthma presented to the emergency department complaining of a 7-day history of fever, diffuse myalgias, nausea, vomiting, diarrhea, and pain in his right upper quadrant, right shoulder, and left thigh. Cultures of blood, bronchoalveolar fluid, and surface and surgical swabs from the patient's left lower extremity grew A. haemolyticum. The patient was successfully treated with intravenous penicillin G 4 million units every 4 hours and azithromycin 500 mg once daily for 14 days. Within 36 hours after initiation of focused therapy, he became afebrile, pain decreased, and pulmonary symptoms abated. Oral azithromycin 500 mg/day for an additional 3 weeks was prescribed on discharge, and the patient showed no relapse at 2-month follow-up.. A. haemolyticum is a weakly acid-fast, branching gram-positive bacillus most commonly implicated in pharyngitis in healthy adolescents and skin and soft-tissue infections in older, immunocompromised patients. Systemic infections are rarely reported in the literature. This organism remains susceptible to most classes of antimicrobials, including penicillins, cephalosporins, carbapenems, macrolides, tetracyclines, clindamycin, and vancomycin. Routine resistance has been reported only with trimethoprim/sulfamethoxazole.. To our knowledge, there are no published case reports of severe sepsis caused by A. haemolyticum. While treatment options are numerous, we recommend the use of intravenous penicillin or a cephalosporin as first-line pharmacologic management of deep-seated infections caused by this rare organism.

Topics: Actinomycetales Infections; Adolescent; Anti-Bacterial Agents; Arcanobacterium; Azithromycin; Humans; Male; Penicillins; Pneumonia, Bacterial; Pyomyositis; Sepsis

Before highly active antiretroviral therapy (HAART) has become available, antibiotic treatment was usually unable to eradicate Rhodococcus (R.) equi infection in HIV-infected patients, although some clinical improvement could be observed in most cases. There are limited data on the outcome of treatment of R. equi pneumonia in the HAART era. We report on a 52-year-old HIV-infected man who presented in poor general condition with an extensive lung cavitation lesion caused by R. equi. The patient recalled exposure to horses on several occasions. R. equi was cultured from the sputum and the isolate was sensitive to imipenem vancomycin, co-trimoxazole, erythromycin, azithromycin, ciprofloxacin and rifampicin. The CD4+ lymphocyte count was 5 cells/mm3 (0.9%) and his plasma HIV-1 RNA viral load was 101000 copies/mL. The patient was successfully treated with a combination of antibiotics that included azithromycin both as part of an initial and suppressive regimen together with antiretroviral treatment. Surgery was not needed and the patient had no relapse for more than five years after the diagnosis and for more than 3 years of suppressive therapy discontinuation. Our literature search revealed 27 patients treated for R. equi infection in the HAART era. However, details on antimicrobial treatment were given in only 3 cases. The optimal drug regimen and duration of treatment for R. equi pneumonia have not yet been established. Because drug resistance may occur during single agent therapy, it has been suggested that at least two antibiotics to which R. equi is susceptible be given. The recommended choices usually include imipenem, antipseudomonal aminoglycosides, erythromycin or azithromycin, vancomycin, rifampin, and levofloxacin. To our knowledge this is the first documented case of long term remission of R. equi pneumonia in an HIV-infected man treated with azithromycin as part of his antibiotic regimen and HAART.

Topics: Actinomycetales Infections; AIDS-Related Opportunistic Infections; Antiretroviral Therapy, Highly Active; Azithromycin; HIV Infections; HIV-1; Humans; Male; Middle Aged; Pneumonia, Bacterial; Rhodococcus equi

Infection with Rhodococcus equi is an important cause of pneumonia in foals, but other organ systems may also be affected. The intracellular presence of R. equi and the formation of granulomatous and suppurative inflammatory tissue mean that prolonged treatment is needed. The pharmacological properties of the combination of erythromycin and rifampicin have improved the survival of foals infected with R. equi; however, erythromycin can cause adverse reactions in foals and mares, which has prompted the search for alternative therapies. The combination of azithromycin or clarithromycin with rifampicin seems to be a promising alternative. However these combinations are expensive and adverse effects remain to be determined, especially in the dams of treated foals. Thus correct diagnosis and appropriate use of drugs are essential for the treatment of R. equi infection in foals.

Topics: Actinomycetales Infections; Animals; Animals, Newborn; Anti-Bacterial Agents; Azithromycin; Clarithromycin; Drug Therapy, Combination; Erythromycin; Horse Diseases; Horses; Pneumonia, Bacterial; Rhodococcus equi; Rifampin; Treatment Outcome

Given the importance of rifampin in treatment protocols for tuberculosis in people, its use in veterinary medicine is under increasing scrutiny in some countries and alternatives might be needed in the near future.. This study was set up to evaluate whether azithromycin combined with doxycycline is effective for the treatment of bronchopneumonia in foals and noninferior to the combination of azithromycin and rifampin.. This is a controlled, randomised and double-blinded clinical trial. Two hundred and forty foals on a farm endemic for infections caused by Rhodococcus equi were involved.. Foals with ultrasonographic pulmonary lesions (lesion score 10-15 cm) were allocated to 3 groups: azithromycin-doxycycline orally (n = 81); azithromycin-rifampin orally (n = 81); or untreated controls (n = 78). Physical examination and thoracic ultrasonography were performed by individuals unaware of treatment group assignment. Foals that worsened were considered treatment failures and removed from the study.. The proportion of foals that recovered was significantly higher for foals treated with azithromycin-doxycycline (80 of 81) or azithromycin-rifampin (81 of 81) compared with that of control foals (57 of 78). The difference in the percentage of efficacy of azithromycin-rifampin vs azithromycin-doxycycline was 1.2% (90% CI = -0.78% to 3.5%) which did not cross the predetermined noninferiority limit of 10%. Therefore, azithromycin-doxycycline was noninferior to azithromycin-rifampin within the predetermined noninferiority limit.. The study was performed on a single farm, and recovery rates may differ in other locations.. Azithromycin-doxycycline was noninferior to azithromycin-rifampin for the treatment of bronchopneumonia in this farm.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Bronchopneumonia; Doxycycline; Horse Diseases; Horses; Rhodococcus equi

There is conflicting data regarding the efficacy of tulathromycin for the treatment of foals with bronchopneumonia.. Tulathromycin is effective for the treatment of bronchopneumonia in foals and noninferior to the combination of azithromycin and rifampin.. A total of 240 foals on a farm endemic for infections caused by Rhodococcus equi.. In a controlled, randomized, and double-blinded clinical trial, foals with ultrasonographic pulmonary lesions (abscess score 10-15 cm) were allocated to 3 groups: 1-tulathromycin IM q 7 days (n = 80); 2-azithromycin-rifampin, orally q24h (n = 80); or 3-untreated controls (n = 80). Physical examination and thoracic ultrasonography were performed by individuals unaware of treatment group assignment. Foals that worsened were considered treatment failures and removed from the study.. The proportion of foals that recovered was significantly higher for foals treated with tulathromycin (70 of 79) or azithromycin-rifampin (76 of 80) compared to that of control foals (22 of 80). The difference in the percentage of efficacy of azithromycin-rifampin versus tulathromycin was 6.4% (90% CI = -0.72-13.5%). Given that the confidence interval crossed the predetermined noninferiority limit of 10%, the null hypothesis that the response rate in the azithromycin-rifampin group is superior to that of the tulathromycin group could not be rejected. Resolution of ultrasonographic lesions occurred faster in foals treated with azithromycin-rifampin than in foals treated with tulathromycin.. Tulathromycin was effective for the treatment of bronchopneumonia in foals at this farm but not as effective as the combination of azithromycin-rifampin.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Bronchopneumonia; Disaccharides; Double-Blind Method; Drug Therapy, Combination; Female; Heterocyclic Compounds; Horse Diseases; Horses; Male; Rhodococcus equi; Rifampin; Treatment Outcome

Gamithromycin is active in vitro against the bacterial agents most commonly associated with bronchopneumonia in older foals. However, the clinical efficacy and safety of this drug have not been investigated.. Gamithromycin is effective for the treatment of bronchopneumonia in foals.. One hundred and twenty-one foals on a farm endemic for infections caused by Rhodococcus equi.. In a controlled, randomized, and double blinded clinical trial, foals with ultrasonographic evidence of pulmonary abscesses (abscess score 8.0-20 cm) were randomly allocated in 3 treatment groups: (1) gamithromycin IM q7 days (n = 40); (2) azithromycin with rifampin, PO q24h (n = 40); or (3) no antimicrobial treatment (controls; n = 41). Physical examination and thoracic ultrasonography were performed by individuals unaware of treatment group assignment. Foals that worsened were removed from the study.. The proportion of foals that recovered without the need to be removed from the study was significantly higher for foals treated with gamithromycin (38 of 40) or azithromycin with rifampin (39 of 40) than for controls (32 of 41). Treatment with gamithromycin or with azithromycin-rifampin resulted in a significantly faster decrease in the clinical score and abscess score compared to the controls. Adverse reactions characterized by colic (n = 18) and hind limb lameness (n = 14) were observed only in foals treated with gamithromycin.. Gamithromycin was noninferior to azithromycin with rifampin for the treatment of bronchopneumonia in the study population but had a higher frequency of adverse reactions.

Topics: Abscess; Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Bronchopneumonia; Double-Blind Method; Drug Therapy, Combination; Female; Horse Diseases; Horses; Macrolides; Male; Rhodococcus equi; Rifampin

The objectives of the present study were to determine the relative efficacy of tulathromycin, azithromycin, or azithromycin with rifampin for the treatment of pulmonary abscesses on a farm with endemic infections caused by Rhodococcus equi. Foals with ultrasonographic evidence of pulmonary abscesses (abscess score 8.0-15 cm; n=120) were randomly allocated in four equal treatment groups: (1) tulathromycin intramuscularly; (2) azithromycin monotherapy, orally; (3) azithromycin with rifampin, orally; (4) saline intramuscularly as a placebo. Physical examination and thoracic ultrasonography were performed by individuals unaware of treatment group assignment. Foals that worsened were removed from the study. The proportion of foals that recovered without the need for a change in therapy was significantly higher for foals treated with azithromycin (29 of 30) or azithromycin with rifampin (28 of 30) than for foals treated with a placebo (20 of 30). Additionally, azithromycin or azithromycin with rifampin resulted in a significantly faster decrease in the number of abscesses and abscess score compared with a placebo. The proportion of foals treated with tulathromycin that recovered (27 of 30) was not significantly different from that of foals treated with a placebo. Azithromycin alone or in combination with rifampin was beneficial in the study population.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Disaccharides; Double-Blind Method; Drug Therapy, Combination; Endemic Diseases; Germany; Heterocyclic Compounds; Horse Diseases; Horses; Lung Abscess; Pneumonia, Bacterial; Rhodococcus equi; Rifampin; Severity of Illness Index; Treatment Outcome

Mass antimicrobial treatment of foals with small ultrasonographic pulmonary lesions is common on farms with endemic disease caused by Rhodococcus equi. The objectives of this study were to compare the relative efficacy of three antimicrobial protocols for the treatment of pulmonary abscesses on a farm with endemic infections caused by R. equi and to determine the frequency of spontaneous resolution of subclinical pulmonary lesions. Foals with ultrasonographic evidence of pulmonary abscesses ≥ 1.0 cm in diameter (n=128) were randomly allocated to one of four equal treatment groups. Animals with respiratory distress or severe pulmonary lesions were excluded from the study. Treatment groups consisted of: (1) tulathromycin intramuscularly; (2) azithromycin monotherapy orally; (3) azithromycin in combination with rifampin orally; and (4) glucose orally as a placebo. Physical examination, thoracic ultrasonography and white blood cell (WBC) counts were performed weekly by individuals unaware of treatment group assignment. Foals that worsened were removed from the study and treated with azithromycin and rifampin. Overall, 14/32 (43.8%) foals in the placebo group recovered without the need for therapy. The proportion of foals that responded to the initial therapy, the duration of therapy, the kinetics of ultrasonographic lesion resolution, the proportion of foals that had to be removed from the study and the number of days to removal from the study did not differ significantly between treatment groups. The study showed that many foals with pulmonary abscesses recover without antimicrobial therapy. Moreover, treatment of sub-clinically affected foals with antimicrobial agents did not significantly hasten recovery.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Disaccharides; Double-Blind Method; Drug Therapy, Combination; Endemic Diseases; Female; Heterocyclic Compounds; Horse Diseases; Horses; Lung Abscess; Male; Rhodococcus equi; Rifampin; Time Factors; Treatment Failure

To determine the effect of azithromycin chemoprophylaxis on the cumulative incidence of pneumonia caused by Rhodococcus equi, age at onset of pneumonia, and minimum inhibitory concentration (MIC) of azithromycin for R equi isolates cultured from fecal and clinical samples.. Controlled, randomized clinical trial.. 338 foals born and raised at 10 equine breeding farms; each farm had a history of endemic R equi infections.. Group 1 foals were control foals, and group 2 foals were treated with azithromycin (10 mg/kg [4.5 mg/lb], PO, q 48 h) during the first 2 weeks after birth. Foals were monitored for development of pneumonia attributable to R equi infection and for adverse effects of azithromycin. Isolates of R equi were tested for susceptibility to azithromycin.. The proportion of R equi-affected foals was significantly higher for control foals (20.8%) than for azithromycin-treated foals (5.3%). Adverse effects of azithromycin treatment were not detected, and there were no significant differences between groups for the MICs of azithromycin for R equi isolates cultured from fecal or clinical samples.. Azithromycin chemoprophylaxis effectively reduced the cumulative incidence of pneumonia attributable to R equi among foals at breeding farms with endemic R equi infections. There was no evidence of resistance to azithromycin. Nonetheless, caution must be used because it is possible that resistance could develop with widespread use of azithromycin as a preventative treatment. Further investigation is needed before azithromycin chemoprophylaxis can be recommended for control of R equi infections.

Topics: Actinomycetales Infections; Animals; Animals, Newborn; Anti-Bacterial Agents; Antibiotic Prophylaxis; Azithromycin; Dose-Response Relationship, Drug; Drug Resistance, Bacterial; Female; Horse Diseases; Horses; Male; Microbial Sensitivity Tests; Pneumonia, Bacterial; Rhodococcus equi; Treatment Outcome

Mainstay therapy for rhodococcosis in foals is the combination of rifampicin and a macrolide. While emergence of resistance to rifampicin and macrolides has been reported, studies demonstrating the development of resistance to such drugs is limited in necropsied foals with rhodococcosis. In this study, the foal necropsy records between 01/01/2011 and 08/30/2019 were reviewed for culture-positive R. equi with MICs and, whether or not the affected foals received any mainstay dual therapy before their deaths. Resistance to antimicrobials in the R. equi isolates from necropsied foals were then compared between treated foals with dual therapy and untreated foals to determine the association between the administration of antimicrobials and development of the drug resistance. In a total of 256 R. equi isolates from each of the 256 necropsied foals with rhodococcosis, rifampicin, azithromycin, clarithromycin and erythromycin showed high rates of resistance, 22.65 %, 16.01 %, 14.84 % and 15.23 %, respectively. The most active antimicrobials exhibiting MIC

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Clarithromycin; Drug Resistance, Multiple, Bacterial; Erythromycin; Horse Diseases; Horses; Microbial Sensitivity Tests; Rhodococcus equi

The objective of this study was to determine the prevalence of

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Clarithromycin; Drug Resistance, Multiple, Bacterial; Equidae; Erythromycin; Feces; Horses; Kentucky; Microbial Sensitivity Tests; Musculoskeletal Diseases; Prevalence; Respiratory System; Rhodococcus equi; Rifampin; Soft Tissue Infections

Trueperella pyogenes is one of the most important microorganisms causing metritis in post-partum cattle. Co-infection with other bacterial species such as Escherichia coli or Fusobacterium necrofurom increases the severity of the disease and the persistence of bacteria in utero. The aim of this study was to investigate the frequency of T. pyogenes strains, and their virulence and antimicrobial resistant profiles in metritis cases. The study was carried out on 200 samples obtained from metritis discharges of postpartum cattle on 18 farms around Tehran, Iran. Sixty-five T. pyogenes isolates (32.5%) were identified, of which 16 isolates were detected as pure cultures and the other 49 isolates from cultures most commonly mixed with E. coli or F. necrofurom. In terms of diversity in biochemical characteristic of T. pyogenes strains, 8 different biotypes were identified among the isolates. Single or multi antimicrobial resistance was observed in 48 isolates (73.9%), which was mostly against trimethoprim sulfamethoxazole, azithromycin, erythromycin and streptomycin. The tetracycline resistance gene tetW and macrolide resistance genes ermB and ermX were detected in 30, 18 and 25 isolates, respectively. In the screening of genes encoding virulence factors, fimA and plo genes were identified in all tested isolates. Genes encoding nanP, nanH, fimC, fimG, fimE and cbpA were detected in 50, 54, 45, 40, 50 and 37 of isolates, respectively. Thirteen different genotypes were observed in these T. pyogenes isolates. A significant association between clonal types and virulence factor genes, biochemical profile, CAMP test result, severity of the disease and sampling time was detected.

Topics: Actinomycetaceae; Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Bacterial Typing Techniques; Cattle; Clone Cells; Drug Resistance, Multiple, Bacterial; Erythromycin; Escherichia coli; Escherichia coli Infections; Female; Fusobacterium; Fusobacterium Infections; Genes, Bacterial; Iran; Parturition; Puerperal Infection; Streptomycin; Trimethoprim, Sulfamethoxazole Drug Combination; Uterus; Virulence Factors

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Drug Combinations; Drug Compounding; Drug Synergism; Humans; Microbial Sensitivity Tests; Powders; Rhodococcus equi; Rifampin; THP-1 Cells; Toxicity Tests; Zoonoses

A 33-year-old Caucasian man with end-stage renal disease secondary to biopsy-proven IgA nephropathy, managed with continuous ambulatory peritoneal dialysis (PD), presented with PD-related peritonitis, the causal organism being a non-branching Gram-positive bacillus, Rhodococcus equi. Initial empirical Gram positive and negative coverage with cefazolin and ceftazidime was unsuccessful, but following isolation of the organism, and conversion to intraperitoneal vancomycin and oral ciprofloxacin, the peritonitis episode resolved. At day 10, vancomycin was switched to azithromycin for a total of 6 weeks of antimicrobial therapy. The PD catheter was preserved, and the patient remained peritonitis-free at 6 months of follow-up.

Topics: Actinomycetales Infections; Adult; Anti-Infective Agents; Australia; Azithromycin; Ciprofloxacin; Drug Therapy, Combination; Follow-Up Studies; Humans; Kidney Failure, Chronic; Male; Peritoneal Dialysis, Continuous Ambulatory; Peritonitis; Rhodococcus equi; Treatment Outcome; Vancomycin

A 37-year-old immunocompetent woman was evaluated for progressive swelling of her left breast. Magnetic resonance imaging (MRI) showed multiple hypo-intense solid lesions and could not exclude breast cancer. Tissue biopsy was suggestive of granulomatous mastitis without any evidence of malignancy. Culture of the specimen in brain heart infusion broth grew Rhodococcus equi. The patient responded well to combination therapy with ciprofloxacin and azithromycin, and the lesions regressed in follow-up MRI. To the best of our knowledge, this is the first report of R. equi granulomatous mastitis. Accurate identification of this rare pathogen is necessary to provide appropriate treatment in granulomatous mastitis.

Topics: Actinomycetales Infections; Adult; Anti-Bacterial Agents; Azithromycin; Biopsy, Fine-Needle; Ciprofloxacin; Drug Therapy, Combination; Female; Granulomatous Mastitis; Humans; Immunocompetence; Magnetic Resonance Imaging; Radiography; Rhodococcus equi; Treatment Outcome

The objectives of this study were to determine the mutant prevention concentration (MPC), time above the MPC and mutant selection window for 10 antimicrobial agents against Rhodococcus equi and to determine if the combination of a macrolide with rifampin would decrease emergence of resistant mutants. Antimicrobial agents investigated (erythromycin, clarithromycin, azithromycin, rifampin, amikacin, gentamicin, enrofloxacin, vancomycin, imipenem, and doxycycline) were selected based on in vitro activity and frequency of use in foals or people infected with R. equi. Each antimicrobial agent or combination of agents was evaluated against four virulent strains of R. equi. MPC were determined using an agar plate assay. Pharmacodynamic parameters were calculated using published plasma and pulmonary pharmacokinetic variables. There was a significant (P<0.001) effect of the type of antimicrobial agent on the MPC. The MPC of clarithromycin (1.0 μg/ml) was significantly lower and the MPC of rifampin and amikacin (512 and 384 μg/ml, respectively) were significantly higher than that of all other antimicrobial agents tested. Combining erythromycin, clarithromycin, or azithromycin with rifampin resulted in a significant (P≤0.005) decrease in MPC and MPC/MIC ratio. When MIC and MPC were combined with pharmacokinetic variables, only gentamicin and vancomycin were predicted to achieve plasma concentrations above the MPC for any given periods of time. Only clarithromycin and the combination clarithromycin-rifampin were predicted to achieve concentrations in bronchoalveolar cells and pulmonary epithelial lining fluid above the MPC for the entire dosing interval. In conclusion, the combination of a macrolide with rifampin considerably decreases the emergence of resistant mutants of R. equi.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Clarithromycin; Erythromycin; Gentamicins; Horse Diseases; Horses; Macrolides; Microbial Sensitivity Tests; Mutation; Rhodococcus equi; Rifampin; Vancomycin

Three cohorts of juvenile and subadult Chinook salmon Oncorhynchus tshawytscha received multiple treatments with macrolide antibiotics for bacterial kidney disease (BKD) during rearing in a captive broodstock program. A total of 77 mortalities among the cohorts were screened for Renibacterium salmoninarum, the etiologic agent of BKD, by agar culture from kidney, and isolates from 7 fish were suitable for growth testing in the presence of macrolide antibiotics. The minimum inhibitory concentration (MIC) of erythromycin and azithromycin was determined by a modification of the standardized broth assay using defined medium. The American Type Culture Collection (ATCC) type strain 33209 exhibited a MIC of 0.008 microg m(-1) to either erythromycin or azithromycin. Isolates from 3 fish displayed MICs identical to the MICs for the ATCC type strain 33209. In contrast, isolates from 4 fish exhibited higher MICs, ranging between 0.125 and 0.250 microg ml(-1) for erythromycin and between 0.016 and 0.031 microg ml(-1) for azithromycin. Sequence analysis of the mutational hotspots for macrolide resistance in the 23S rDNA gene and the open reading frames of ribosomal proteins L4 and L22 found identical sequences among all isolates, indicating that the phenotype was not due to mutations associated with the drug-binding site of 23S rRNA. These results are the first report of R. salmoninarum with reduced susceptibility to macrolide antibiotics isolated from fish receiving multiple antibiotic treatments.

Topics: Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Colony Count, Microbial; DNA, Bacterial; DNA, Ribosomal; Dose-Response Relationship, Drug; Erythromycin; Fish Diseases; Kidney; Kidney Diseases; Macrolides; Microbial Sensitivity Tests; Micrococcaceae; Mutation; Open Reading Frames; RNA, Ribosomal, 23S; Salmon

Topics: Actinomycetales Infections; Anti-Bacterial Agents; Azithromycin; Drug Therapy, Combination; Female; Humans; Metronidazole; Mobiluncus; Polymerase Chain Reaction; Secondary Prevention; Vagina; Vaginosis, Bacterial

Topics: Abscess; Actinomycetales Infections; Animals; Anti-Bacterial Agents; Azithromycin; Diagnosis, Differential; Horse Diseases; Horses; Lung; Male; Pneumonia, Bacterial; Radiography, Thoracic; Rhodococcus equi; Rifampin; Ultrasonography

A 3-month-old female Arabian horse was evaluated because of fever, respiratory distress, lethargy, and decreased appetite of 5 days' duration. Pleural effusion was diagnosed on the basis of ultrasonographic and radiographic examinations. Cytologic examination of pleural fluid collected via thoracocentesis revealed septic inflammation; bacteriologic culture of a sample of that fluid yielded Rhodococcus equi. A large intra-abdominal mass adjacent to the body wall was identified ultrasonographically. A specimen of the mass was collected via aspiration; the specimen was identified cytologically as purulent exudate that contained large numbers of rod-shaped bacteria, which confirmed abdominal abscess formation. Bacteriologic culture of a sample of the exudate also yielded R. equi. The foal was treated with azithromycin (10 mg/kg [4.5 mg/lb], PO, q 24 h for 5 days then q 48 h) and rifampin (5 mg/kg [2.3 mg/lb], PO, q 12 h) for 8 weeks and metronidazole (15 mg/kg [6.8 mg/lb], PO, q 8 h) for 3 weeks. Clinically, the foal responded to antimicrobial treatment within 2 weeks. At 8 weeks after the initial evaluation, ultrasonographic examination of the foal revealed resolution of the pleural effusion and abdominal abscess. In foals, R. equi infection typically results in pyogranulomatous pneumonia, and pleural effusion is an uncommon clinical sign. The combination of azithromycin and rifampin appears to be an effective treatment for R. equi infection in foals.

Topics: Abdominal Abscess; Actinomycetales Infections; Animals; Animals, Newborn; Anti-Bacterial Agents; Azithromycin; Drug Resistance, Bacterial; Female; Horse Diseases; Horses; Pneumonia, Bacterial; Rhodococcus equi; Rifampin; Treatment Outcome; Ultrasonography

Topics: Actinomycetaceae; Actinomycetales Infections; Adult; Anti-Bacterial Agents; Azithromycin; Exanthema; Female; Humans; Pharyngitis

The properties of azithromycin suggest that it may be an alternative to erythromycin for treatment of Rhodococcus equi pneumonia in foals. To investigate this possibility, the disposition of azithromycin in plasma, polymorphonuclear leukocytes (PMN), and alveolar cells was examined after a single administration in foals. Azithromycin suspension was administered orally (p.o.) at a dose of 10 mg/kg to five healthy 2-3-month-old foals. Two weeks later, azithromycin for injection was administered by intravenous (i.v.) infusion at a dose of 5 mg/kg to the same foals. Plasma samples were collected after p.o. and i.v. administration. Peripheral blood PMN and bronchoalveolar lavage fluid and alveolar cells were collected after p.o. administration. Azithromycin concentrations were determined by reverse-phase high-performance liquid chromatography (HPLC) with coulometric electrochemical detection. Azithromycin p.o. absorption was variable with a mean systemic availability of 39% (+/-20%). The plasma half-life was 16 and 18.3 h after i.v. and p.o. administration, respectively. Azithromycin had a very large volume of distribution (V(d)) of 11.6 L/kg [V(d(ss))] and 12.4 L/kg [V(d(area))]. The large V(d) can be attributed to high tissue and intracellular concentrations, exhibited by the high concentration of azithromycin in PMN and alveolar cells. The PMN half-life was 49.2 h. Dosage of 10 mg/kg of azithromycin p.o. once daily for foals with R. equi pneumonia is recommended for further study.

Topics: Actinomycetales Infections; Administration, Oral; Animals; Animals, Newborn; Anti-Bacterial Agents; Area Under Curve; Azithromycin; Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Female; Horse Diseases; Horses; Infusions, Intravenous; Macrophages, Alveolar; Male; Phagocytes; Rhodococcus equi

Rhodococcus equi is a common cause of pneumonia in animals. Human infection is rare. Increasing number of cases are being reported in immunosuppressed individuals mostly associated with HIV infection, but also in solid organ transplant recipients and leukemia/lymphoma patients. We report on an adult male who developed pneumonia and gastroenteritis 4 mo after receiving a renal transplant. CT scan of the lungs showed a dominant 2.5-cm upper lobe lung mass and smaller bilateral nodules. He underwent a diagnostic bronchoscopy with fine-needle aspiration biopsy of the largest lung nodule. Smears showed histiocytic granulomatous inflammation, foamy macrophages, and acute inflammatory exudate. Scattered foamy macrophages displayed intracellular coccobacilli identifiable on Diff-Quik stain. A few cells with changes suggestive of viral inclusions were identified. Cytomegalovirus (CMV) immunostain was positive in the cell block sections. Lung cultures grew R. equi. To the best of our knowledge, this is the first report of coinfection with R. equi and CMV.

Topics: Actinomycetales Infections; Adult; Anti-Bacterial Agents; Anti-Infective Agents; Antigens, Viral; Antiviral Agents; Azithromycin; Biopsy, Needle; Cytomegalovirus; Cytomegalovirus Infections; Ganciclovir; Humans; Immunocompromised Host; Kidney Transplantation; Male; Ofloxacin; Pneumonia, Bacterial; Pneumonia, Viral; Postoperative Complications; Rhodococcus; Tomography, X-Ray Computed; Vancomycin

Topics: Actinomycetales Infections; Aged; Anti-Bacterial Agents; Azithromycin; Humans; Male; Peritoneal Dialysis, Continuous Ambulatory; Peritonitis; Rhodococcus equi

Infections of Rhodococcus equi, a well-known pathogen in animals which causes cavitated pneumonia similar to that caused by mycobacteria, were studied in three HIV-infected patients. This microorganism was isolated in the bronchoalveolar washings of two patients and in the sputum of the third. In two patients, Rh. equi represented the first clinical opportunistic manifestation of HIV disease. One patient died of concomitant Pneumocystis infection. The eradication of the microorganism occurred in two out of three patients. It was found that no isolates were resistant to erythromycin, claritromycin, rifampin, vancomycin, teicoplanin, imipenem, gentamycin or azithromycin (MIC values < or = 0.1 microgram/ml). Moreover, the quinolones (ciprofloxacin and ofloxacin) were found to be less effective, whereas neither the beta-lactam antibiotics nor chloramphenicol were effective therapy for this microrganism. At least two antimicrobial agents should be given contemporaneously to treat these infections for a period of up to several months. Our results suggest that the combinations erythromycin + rifampin or imipenem + teicoplanin are the most effective treatments in Rh. equi infections.

Topics: Actinomycetales Infections; Adult; AIDS-Related Opportunistic Infections; Anti-Bacterial Agents; Azithromycin; Bacteremia; Bronchoalveolar Lavage Fluid; Clarithromycin; Drug Resistance, Microbial; Drug Synergism; Drug Therapy, Combination; Erythromycin; Female; Gentamicins; HIV Infections; Humans; Imipenem; Male; Pleurisy; Pneumonia, Bacterial; Rhodococcus equi; Rifampin; Sputum; Teicoplanin; Vancomycin