Presumed clostridial and aerobic bacterial infections of the cornea in two horses.

Microscopic examination of Gram-stained tissue specimens collected from severe corneal ulcers in 2 horses revealed large gram-positive rods suggestive of Clostridium spp. Clostridium perfringens was isolated from specimens collected from horse 1; anaerobic organisms were not detected in specimens from horse 2. Aerobic bacterial culture revealed Aeromonas hydrophila and Enterobacter cloacae in specimens collected from horses 1 and 2, respectively. An insect exoskeleton was presumed to be the underlying cause of ulceration in horse 1. Cause of ulceration in horse 2 was not determined. Antibiotics used to treat the corneal infections included ticarcillin disodium-clavulanic acid injected one time subconjunctivally and chloramphenicol applied topically at frequent intervals. Horse 2 also received penicillin or trimethoprim-sulfadiazine. Small leukomas were the only lesion remaining between 2 and 7 months after initial evaluation. Chloramphenicol applied topically appears to be an effective treatment against clostridial corneal infections in horses.

Clinical appearances, healing patterns, risk factors, and outcomes of horses with fungal keratitis: 53 cases (1978-1996)

OBJECTIVE: To compare initial clinical appearances, healing mechanisms, risk factors, and outcomes of horses with fungal keratitis. DESIGN: Retrospective analysis. ANIMALS: 52 horses (53 eyes) with fungal keratitis. PROCEDURE: Medical records and clinical photographs of eyes were reviewed. Keratomycoses were categorized on the basis of clinical appearance at initial examination and pattern of healing. RESULTS: Five distinct forms of mycotic keratitis were recognized. Of 53 affected eyes, 34 (64%) retained sight and had varying degrees of corneal scarring after treatment, 6 (11%) had a cosmetic appearance but were blind, and 13 (25%) were enucleated. Bacterial-like ulcers were the most frequent type and the most difficult for predicting outcome. Eyes affected by superficial fungal keratitis were likely to be chronically infected and to require debridement and extended treatment but usually healed with minimal scarring. Keratomycosis with a surrounding furrow resulted in a grave prognosis. Aspergillus organisms were isolated from 9 of 10 such eyes. Cake-frosting material was a positive prognostic sign. Fungal corneal stromal abscesses tended to be caused by yeast. CLINICAL IMPLICATIONS: This information will aid practitioners in recognizing various forms of fungal keratitis and guide them when making therapeutic decisions and prognoses for affected horses.

Evaluation of itraconazole-dimethyl sulfoxide ointment for treatment of keratomycosis in nine horses.

OBJECTIVE: To evaluate the efficacy of itraconazole-dimethyl sulfoxide ointment for treatment of keratomycosis in horses in the northeastern United States. DESIGN: Prospective clinical trial. ANIMALS: 9 horses (10 affected eyes). PROCEDURE: All horses treated for keratomycosis at Cornell University between July 1994 and July 1996 were included in the study. The diagnosis of keratomycosis was confirmed by cytologic examination, and all horses were treated with 0.25 ml of a 1% itraconazole-30% dimethyl sulfoxide petrolatum-based ointment, applied to the affected eye every 4 hours. RESULTS: Topical application of itraconazole-dimethyl sulfoxide ointment (q 4 h) resolved keratomycosis in 8 of 10 eyes; mean duration of treatment was 34.6 days (range, 16 to 53 days). CLINICAL IMPLICATIONS: Results of this study indicate topical administration of itraconazole-dimethyl sulfoxide ointment may provide an additional treatment option for horses with keratomycosis.

Evaluation of a commercial automated system and software for the identification of veterinary bacterial isolates.

A commercial gram-negative bacterial autoidentification plate was originally developed using bacterial isolates of human origin. Three veterinary diagnostic laboratories conducted a 2-phase trial to enhance the database for veterinary use. The first phase consisted of testing the plate with 447 bacterial isolates of veterinary origin and incorporating that data into the existing database. Emphasis was placed on the Actinobacillus, Bordetella, Pasteurella and Enterobacteriaceae groups, since the Pseudomonas taxon was quite complete. The second phase of the trial consisted of evaluating the enhanced database using 270 clinical veterinary isolates normally encountered in veterinary laboratories. For the Actinobacillus, Bordetella, Pasteurella and Enterobacteriaceae groups, 72% of the bacterial isolates were identified correctly to genus and 85% to species after 18 hours incubation. All identifications in phase 1 and phase 2 were confirmed using conventional methods.

Salmonella enteritidis in commercial layer farms in New York state; environmental survey results and significance of available monitoring tests.

Seven hundred fifty-one environmental samples were collected from 76 chicken layer houses in a voluntary Salmonella enteritidis (SE) survey study carried out in New York state between January 15 and April 8, 1991. SE was recovered from both houses on 1 farm. Sampling of manure pits and mice in hen houses was useful for SE screening. Phage types of SE from the environment, birds, and mice were identical. The rapid whole-blood test was unreliable, and culture of cloacal swabs was inadequate for detection of SE carriers. Culture of organs from chickens did not correlate well with results of environmental samples.

Embryonic loss in pony mares induced by intrauterine infusion of Candida parapsilosis.

Pony mares which were detected pregnant by transrectal ultrasonography received a single intrauterine infusion of either sterile saline (control, n = 12 mares) or 10(6)Candida parapsilosis (treated, n = 12 mares) between Days 11 to 14 postovulation. Subsequent embryonic loss was studied by daily ultrasonography of the mare's uterus, by serum progesterone levels, by endometrial swabs for cytologic and microbiologic examination and by endometrial biopsies that were taken after embryonic loss was detected. Significantly fewer (P<0.01) embryonic losses occurred in control than in treated mares (4 12 vs 12 12 ). The mean interval from intrauterine infusion until embryonic loss was 5.8 +/- 2.8 d for control mares (n = 4) and 2.1 +/- 0.2 d for treated mares (n = 12). Prior to embryonic loss, moderate to marked edema of the endometrial folds in 12 of 12 treated mares and free fluid in the uterine lumen of 5 of 12 treated mares were detected by ultrasonography. After embryonic loss, Candida parapsilosis was cultured from the uteri of 8 of 12 treated mares, and E . coli was cultured from the uteri of 2 of 4 control mares. Postloss endometrial smears had cytologic evidence of inflammation in 10 of 12 treated mares and 3 of 4 control mares. Intrauterine inoculation of C. parapsilosis consistently induced embryonic loss and may provide a basis to further study the relationship between endometritis and embryonic loss in mares.

A new antibiotic combination for frozen bovine semen 1. Control of mycoplasmas, ureaplasmas, Campylobacter fetus subsp. venerealis and Haemophilus somnus.

Systematic evaluations of new combinations of antibiotics for the control of bovine mycoplasmas, ureaplasmas, Campylobacter fetus subsp. venerealis and Haemophilus somnus in a bovine frozen semen process were made. These organisms were standardized to 10(5) to 10(6) colony forming unit (CFU) and inoculated into each ml of raw semen. Antibiotics in a final volume of 0.02 ml were added to each ml of the raw semen and were contained at the same concentration in the nonglycerol portion of the extenders (whole milk, 20% egg yolk citrate, 20% egg yolk tris, Plus-X, and 28% egg yolk tris). The combination of gentamicin (500 ug/ml) tylosin (100 ug/ml) and Linco-Spectin (300/600 ug/ml) was more effective for the control of mycoplasmas and ureaplasmas and equally effective for the control of C. fetus subsp. venerealis and Haemophilus somnus than the standard combination of penicillin, dihydrostreptomycin and polymyxin B sulfate.

Malignant edema in horses.

Malignant edema (clostridial myositis) was diagnosed in 9 horses with signs of illness that included fever, depression, painful muscular swellings, and toxemia. The infection followed intramuscular injections in 8 horses and developed in a puncture wound in 1 horse. Treatment consisted of surgical fenestration of the involved muscle, high doses of penicillin, nonsteroidal anti-inflammatory agents and analgesics, and supportive fluid therapy. Five horses recovered and 4 died. Those that died had advanced signs of the disease at admission.

Isolation of Actinobacillus lignieresii from enlarged tongue of a horse.

In the horse described herein, Actinobacillus lignieresii was associated with a syndrome identical to wooden tongue in cattle. It responded rapidly to systemic sodium iodide and antibiotic therapy. The definitive diagnosis was based on cytologic examination and culture. If actinobacillosis is suspected, immediate treatment with sodium iodide should be instituted along with supportive therapy.

Bacteriology of acute pelvic inflammatory disease. Suboptimal survival of Neisseria gonorrhoeae in a nonbuffered transport system.

In our earlier study, Neisseria gonorrhoeae was infrequently isolated while Bacteroides fragilis was totally absent from cul-de-sac aspirates of patients with acute pelvic inflammatory disease (PID). Twenty additional women were studied to further elucidate the bacteriology of this disease. Recovery rate of N. gonorrhoeae from cul-de-sac aspirates collected in selective transport medium (Transgrow) was 25 per cent among patients with gonococcal PID, compared to only 8 per cent when specimens were collected in a nonselective transport system (Anaport). In vitro studies confirmed a detrimental effect of the Anaport for survival of N. gonorrhoeae during transport. This suboptimal survival was primarily related to low pH of the transport system under prereduced conditions, and could be corrected when pH of the transport vial was preadjusted and maintained between 6 and 7. B. fragilis was again absent from the cul-de-sac in all patients, while streptococci, peptococci, and peptostreptococci remained the most predominant isolates. These data may explain the empiric observations that penicillin and tetracycline are effective in most cases of acute PID.

Susceptibility of Campylobacter fetus to twenty-two antimicrobial agents.

In vitro susceptibility of 11 recent clinical isolates of Campylobacter fetus to 22 antimicrobial agents was determined by an agar dilution technique. Unlike most obligate anaerobic gram-negative bacilli, C. fetus isolates tested were relatively resistant to penicillin and cephalosporins, but exquisitely susceptible to tetracyclines and aminoglycosides. All strains were also inhibited at concentrations achievable in serum by clindamycin, chloramphenicol, metronidazole, carbenicillin, ticarcillin, and with rare exceptions, ampicillin. They were variably susceptible to lincomycin and erythromycin and highly resistant to vancomycin.

Rapid screening of Veillonella by ultraviolet fluorescence.

Among 51 strains of anaerobic gram-negative cocci belonging to the family Veillonellaceae, all strains of Veillonella (V. parvula and V. alcalescens) displayed red fluorescence under long-wave (366 nm) ultraviolet light, whereas no Acidaminococcus or Megasphaera demonstrated fluorescence. In contrast to Bacteroides melaninogenicus, growth of Veillonella does not require hemin and menadione, and flourescence is rapidly lost upon exposure to air. The fluorescent component of a strain of V. parvula examined could not be extracted in solution with water, ether, methanol, or chloroform, but was readily extracted with 0.4 N NaOH. Spectrophotofluorometrically, the fluorescence maximum of this extract was 660 nm with an excitation maximum of 300 nm, when measured at pH 7.2 and 25 C. Coupled with the Gram stain, ultraviolet fluorescence may be a useful tool for rapid screening of Veillonella and is particularly helpful for detection and, isolation of this organism from mixed culture.

Susceptibility of anaerobic bacteria to metronidazole: relative resistance of non-spore-forming gram-positive baccilli.

Susceptibility of 358 clinical isolates of obligate anaerobes to metronidazole was determined by an agar-dilution technique. Only 66% of all isolates were inhibited by 6.25 mug/ml, whereas 30% required larger than or equal to 50 mug/ml. Considerable variation in susceptibility was observed among different genera and species of bacteria. Fusobacterium was most senstitive, followed by Clostridium, Bacteroides and Peptococcus, Peptostreptococcus, Veillonella and Acidaminococcus, and non-spore-forming gram-positive bacilli. Bacteroides fragilis was more sensitive than other species of Bacteroides. Similarly, Clostridium perfringens was more susceptible than other species of Clostriduim. While metronidazole appears to be a promising antimicrobial agent for infections caused by Fusobacterium, Clostrididium, and B.fragilis, therapy for infections with other anaerobic bacteria should be guided by in vitro tests of sensitiivity.

Comparative susceptibility of anaerobic bacteria to minocycline, doxycycline, and tetracycline.

The comparative susceptibility of 622 recent clinical isolates of anaerobic bacteria to minocycline, doxycycline, and tetracycline was determined by an agar-dilution technique. In addition to Bacteroides fragilis, a variety of other anaerobic bacteria was resistant to achievable blood concentrations of tetracycline (55% inhibited by 6.25 mug/ml) and doxycycline (58% inhibited by 2.5 mug/ml). In contrast, minocycline was significantly more active (P < 0.05) than both doxycycline and tetracycline, and 70% of strains were inhibited by achievable blood concentrations of this antibiotic (2.5 mug/ml). The enhanced activity of minocycline was particularly striking for Peptococcus asaccharolyticus, P. magnus, P. prevotii, Peptostreptococcus anaerobius, and Bacteroides melaninogenicus. Further evaluation of the clinical efficacy of minocycline against anaerobic infections is indicated.