Antibiotic susceptibility of bacteria isolated from cats with ulcerative keratitis in Taiwan

Objectives: To assess the antibiotic susceptibility of bacteria isolated from corneal ulcers in cats. Methods: A total of 92 cats with infected corneal ulcers were swabbed for bacterial culture and the antibiotic sensitivity of the isolates analysed. Results: Bacteria were isolated from 54 of 92 infected eyes with corneal ulcers and purulent discharge. A total of 59 bacterial isolates were obtained from the 54 ulcers. The ratio of Gram-positive to Gram-negative isolates was approximately 3:1. The most commonly isolated Gram-positive bacteria were Staphylococcus species (51 per cent of all isolates), while Pseudomonas aeruginosa (13.5 per cent of all isolates) was the most common Gram-negative bacteria isolated. The Gram-negative isolates demonstrated a greater incidence of antibiotic resistance than the Gram-positive ones. The most effective antibiotics against the isolates were ciprofloxacin, tobramycin and gentamicin, with erythromycin and lincomycin showing the greatest number of resistant isolates. Clinical Significance: Staphylococcus and Pseudomonas species were the most common Gram-positive and Gram-negative bacteria, respectively, isolated from feline eyes with ulcerative keratitis. The second-generation fluoroquinolone, ciprofloxacin and the aminoglycoside gentamicin were found to be highly effective against the majority of isolates.     

A retrospective study of the clinical presentation of 140 dogs and 39 cats with bacteraemia

OBJECTIVES: To evaluate retrospective data from 140 dogs and 39 cats with positive blood cultures that were presented to the Clinic for Small Animal Medicine in Munich from 1995 to 2004. METHODS: The identity of bacteria isolated from blood cultures of dogs and cats with bacteraemia was determined, and clinical and laboratory findings and outcome of animals with Gram-negative versus Gram-positive bacteraemia were compared. RESULTS: Sepsis was diagnosed in 81.7 per cent of dogs and 59.5 per cent of cats with bacteraemia. Escherichia coli was isolated in one third of the animals. Dogs with bacteraemia more often showed monocytosis and increased alkaline phosphatase activity, while in cats, hyperglycaemia was found more commonly. Dogs with Gram-negative bacteraemia had hypoalbuminaemia significantly more often than dogs with Gram-positive bacteraemia, while among the remaining parameters, there were no statistically significant differences. CLINICAL SIGNIFICANCE: Not all dogs and cats with a positive blood culture met the criteria for sepsis. Bacteraemia caused by Gram-positive versus Gram-negative bacteria cannot be distinguished based on clinical or laboratory parameters, and bacterial culture and susceptibility testing have to be performed for the right choice of antibiotic treatment.     

Bacterial culture of blood from critically ill dogs and cats: 100 cases (1985-1987)

Of 100 critically ill dogs and cats, 49 (39 dogs, 10 cats) had bacteremia. Gram-negative bacilli were the most common isolates from the bloodstream of dogs with bacteremia (46%), and gram-positive cocci and anaerobic bacteria were isolated from 36% and 31% of positive cultures, respectively; 15% of positive cultures were polymicrobial. In cats, gram-negative bacilli (especially Salmonella enteritidis) and anaerobic bacteria were the most common isolates, and 30% of positive cultures were polymicrobial. Gram-positive cocci were not isolated from the blood-stream of cats. Odds ratios, adjusted for the combined effects of disease status (severe vs nonsevere), results of bacterial culture of blood result (positive vs negative), and species (dog vs cat) were calculated for mortality in animals in the study. In animals with bacteremia, severe disease increased the risk of death 11.6-fold, compared with the risk in animals with nonsevere disease. Bacteremia increased mortality 10-fold in animals with severe disease, compared with mortality in animals with severe disease without bacteremia. Animals with severe disease and bacteremia were 15.6 times more likely to die than were those with nonsevere disease and negative culture results. In animals with nonsevere disease, culture results (positive vs negative) were not related significantly to mortality. Disease status (severe vs nonsevere) in animals without bacteremia also was not significantly related to mortality. There was no significant difference in overall mortality in dogs, compared with that in cats.(ABSTRACT TRUNCATED AT 250 WORDS)     

The obligate and facultatively anaerobic bacterial flora of the normal feline gingival margin

Samples from the gingival margins of 14 cats considered normal on clinical examination were cultured for facultative and obligate anaerobic bacteria. All mouths were free from any gingival marginal inflammation and tartar build-up; all cats were between 6 and 12 months of age. A mixed growth was obtained from all samples. The mean number of bacterial species per sample was 10.7 with a range of 7-16 isolates. Of the 150 isolates processed, 109 (72.66%) were obligate anaerobes. Of the facultatively anaerobic species, Actinomyces (including A. viscosus, A. hordeovulneris and A. denticolens) comprised 12%, Pasteurella multocida 9.33% of isolates and Propionibacterium species 6% of all isolates. Gram-negative bacilli belonging to the genera Bacteroides and Fusobacterium were isolated from 12 of the 14 samples, and comprised 77% of the obligate anaerobes isolated. Clostridium villosum comprised 10.1% of obligately anaerobic isolates, Wolinella species made up 6.42%, while 4.58% were Peptostreptococcus anaerobius. The most commonly isolated obligately anaerobic species was C. villosum and the most commonly isolated facultatively anaerobic species was P. multocida. These findings show a bacterial flora of the normal feline mouth which is very similar in composition to that of cat fight abscesses and feline pyothorax.     

Oral associated bacterial infection in horses: studies on the normal anaerobic flora from the pharyngeal tonsillar surface and its association with lower respiratory tract and paraoral infections

Two hundred and seventy bacterial isolates were obtained from the pharyngeal tonsillar surface of 12 normal horses and 98 obligatory anaerobic bacteria were characterised. Of these, 57 isolates belonging to 7 genera (Peptostreptococcus (1); Eubacterium (9); Clostridium (6); Veillonella (6); Megasphera (1); Bacteroides (28); Fusobacterium (6)) were identified, and 16 of these were identified to species level (P. anaerobius (1); E. fossor (9); C. villosum (1); B. fragilis (1); B. tectum (2); B. heparinolyticus (2)). Three hundred and twenty isolates were obtained from 23 samples from horses with lower respiratory tract (LRT) or paraoral (PO) bacterial infections. Of the 143 bacteria selected for detailed characterisation, obligate anaerobes accounted for 100 isolates, facultative anaerobes for 42 isolates and obligate aerobes for one isolate. Phenotypic characterisation separated 99 of the isolates into 14 genera. Among the obligately anaerobic species, Gram-positive cocci including P. anaerobius comprised 25% of isolates, E. fossor 11% and other Gram-positive rods (excluding Clostridium sp.) 18% of isolates. The Gram-negative rods comprised B. fragilis 5%, B. heparinolyticus 5%, asaccharolytic pigmented Bacteroides 3% and other Bacteroides 13%, while a so-far unnamed species of Fusobacterium (7%), and Gram-negative corroding rods (3%) were isolated. Among the facultatively anaerobic isolates, S. equi subsp. zooepidemicus accounted for 31% of isolates, followed by Pasteurella spp. 19%, Escherichia coli 17%, Actinomyces spp. 9%, Streptococcus spp. 9%. Incidental facultative isolates were Enterococcus spp. 2%, Enterobacter cloaceae 2%, Actinobacillus spp. 2% and Gram-negative corroding rods 5%. On the basis of the similarities (as determined by DNA hybridization data and/or phenotypic characteristics) of some of the bacterial species (e.g. E. fossor and B. heparinolyticus) isolated from both the normal pharyngeal tonsillar surfaces and LRT and PO diseases of horses, it is considered that the most likely source of bacteria involved in these disease processes is flora from the oral cavity.     

Pharmacodynamics of ibafloxacin in micro-organisms isolated from cats

The pharmacodynamic properties of ibafloxacin were investigated in micro-organisms isolated from cats. Minimal inhibitory concentrations (MIC) of ibafloxacin (racemate, R- and S-enantiomers) and its metabolites (7-hydroxy- and 8-hydroxy-ibafloxacin) and time-kill kinetics were determined against Gram-negative and Gram-positive bacteria isolated from dermal and respiratory and urinary tract infections in cats. Racemic ibafloxacin has a broad spectrum of bactericidal activity against Gram-negative and some Gram-positive bacteria. Escherichia coli and Pasteurella, Klebsiella and Staphylococcus spp. are commonly isolated from feline infections and all are susceptible to ibafloxacin (MIC90 < or = 0.5 microg/mL), whereas Pseudomonas aeruginosa, Proteus mirabilis and Streptococcus spp. are considered intrinsic resistant. Microbiological activity resides primarily in the S-enantiomer of ibafloxacin whereas the R-enantiomer is less active. Killing curves using concentrations of racemic ibafloxacin and 8-hydroxy-ibafloxacin, which are representative of the in vivo situation observed in cats, showed at least 99.9% reduction in viable bacterial isolates from feline clinical samples over 24 h. Bacterial eradication was achieved in cats with Cmax/MIC and AUC/MIC values much lower than the target values previously established in man and laboratory animals. Additional studies in dogs and cats are necessary to define more clearly the surrogate markers of antibacterial activity (i.e. Cmax/MIC, AUC/MIC ratios), which are associated with a good clinical response.     

Antibiotic susceptibility of bacterial isolates from corneal ulcers of dogs in Taiwan

OBJECTIVES: To analyse antibiotic susceptibility of bacteria associated with ulcerative keratitis in dogs. METHODS: Bacteria isolated from 190 eyes with ulcerative keratitis were identified, and the antibiotic susceptibility of isolates was studied. RESULTS: In total, 258 species of bacteria were isolated from the 190 eyes. Of the isolates, 78 per cent were Gram-positive and 28 per cent were Gram-negative bacteria. The most commonly isolated Gram-positive bacteria in dogs were Staphylococcus spp (49 per cent), Streptococcus spp (7 per cent) and Corynebacterium spp (7 per cent); while Pseudomonas aeruginosa (7.6 per cent) and Escherichia coli (5.8 per cent) were the commonest Gram-negative pathogens. Resistance to commonly used ophthalmic antibiotics was seen in Staphylococcus, Streptococcus, Corynebacterium, Pseudomonas and Escherichia species isolates. CLINICAL SIGNIFICANCE: Isolates from dogs with corneal ulcers in Taiwan may be resistant to several commonly used ophthalmic preparations. Ciprofloxacin showed good action against most isolates, with the notable exception of Streptococcus species. Chloramphenicol or cephalothin had the best in vitro action against the Streptococcus species isolates.     

Isolation of obligate anaerobic bacteria from ulcerative keratitis in domestic animals

Objective To determine the frequency of obligate anaerobic bacterial isolation from corneal samples of domestic animals with ulcerative keratitis and to characterize the historical, clinical, cytological, and microbiological features of culture‐positive cases. Animals studied Three hundred and thirty domestic animals with ulcerative keratitis. Procedures Anaerobic bacteriologic culture and Gram stain were performed on corneal samples from consecutive animals examined with suspect septic ulcerative keratitis. Additional corneal diagnostics included: aerobic bacteriologic culture for all species; fungal culture for ungulates; Mycoplasma culture and virus isolation or feline herpesvirus‐1 (FHV‐1) polymerase chain reaction (PCR) for cats. Historical, clinical, and cytological findings were correlated with microbiologic data. Results Anaerobic bacteria were isolated from 13.0% of corneal samples (dogs: 14.0%; horses: 12.9%; cats: 7.9%; alpacas: 18.8%). The most frequent isolates were Clostridium, Peptostreptococcus, Actinomyces, Fusobacterium, and Bacteroides species. The majority of these infections were mixed anaerobic and aerobic bacteria, unless antimicrobial therapy had been administered prior to presentation. The clinical appearance of anaerobic bacterial culture‐positive cases was highly variable. Ocular trauma, pre‐existing corneal disease, previous corneal surgery, and chronic dermatological disease were significantly (P ≤ 0.05) correlated with positive anaerobic cultures in one or more species. Conclusions The results of the present study demonstrate that obligate anaerobic bacteria are present within the intralesional flora of ulcerative keratitis in domestic animals. In most species evaluated, these bacteria were identified infrequently. Anaerobic bacterial infection of the cornea most frequently occurs in association with other ocular pathogens and previous corneal abnormalities.     

In vitro antimicrobial activity of marbofloxacin and enrofloxacin against bacterial strains isolated from companion animals

Fluoroquinolones were originally developed for the Gram-negative aerobic spectrum, but the newer generation agents are also highly effective against some Gram-positive pathogens and cause few adverse effects. Owing to these characteristics, fluoroquinolones are often used in first line therapy in small animal practice. However, their widespread use has raised concern over emerging bacterial resistance. In this study we evaluated the in vitro efficacy of two fluoroquinolones, marbofloxacin and enrofloxacin, on field strains isolated from clinical infections between 2002 and 2005. Our data show that most of the isolates are still sensitive to both antimicrobials and marbofloxacin was more effective than enrofloxacin, especially against P. aeruginosa and beta-Streptococci (P < 0.01). beta-Streptococci demonstrated the greatest resistance to the two study drugs.     

Comparison of bacteriologic culture of blood and necropsy specimens for determining the cause of foal septicemia: 47 cases (1978-1987)

Diagnosis of bacterial septicemia was confirmed by results of bacteriologic culture of antemortem blood samples and/or necropsy specimens obtained from 47 foals up to 8 days old. Gram-negative bacteria were isolated from all 47 foals, and mixed infections with more than one organism were involved in 26 (55%). Escherichia coli, Actinobacillus spp, and Klebsiella pneumoniae were the most frequent isolates, infecting 55, 34, and 23% of foals, respectively. Gram-positive bacteria and anaerobic bacteria were isolated only from foals with mixed infections with gram-negative organisms. Clostridium perfringens was the only anaerobe isolated. In 38 (81%) of 47 foals with confirmed septicemia, blood samples were culture-positive. Thirty-two septicemic foals subsequently died, allowing a comparison to be made between the species of bacteria isolated by culture of blood with those recovered by culture of internal organs at necropsy. Blood failed to yield any gram-negative organisms in 12 (37.5%) of 32 foals from which a gram-negative pathogen was isolated at necropsy. Forty-three percent of the gram-negative bacteria, including 59% of the E coli, and 10% of the gram-positive bacteria found in septicemic foals at necropsy were not detected earlier by results of bacteriologic culture of blood.     

Survey of bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Fortaleza, Ceará, Brazil

OBJECTIVE: The ocular microflora in dogs has not been established in north-east Brazil. Thus, the main aim of this research was to determine the bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Fortaleza, Ceará, Brazil. ANIMALS STUDIED: This study included 60 healthy dogs, 15 dogs with unilateral corneal ulcer, and three dogs with bilateral corneal ulcers. Procedure Samples were taken by a calibrated platinum loop (1 microL) placed directly onto the conjunctival sac and on sterile blood agar. The clinical specimens were incubated at 37 degrees C in an atmosphere of 5% CO2 for 48 h. RESULTS: Of the 120 samples from healthy dogs, only 47 (39%) had positive culture for bacteria, while all of the specimens from eyes with corneal ulcer were positive for bacterial growth. The group of dogs with corneal ulcer had a higher (P < 0.05) number of colony-forming units (CFU) per plate than the group of healthy animals. Of the 59 isolates from healthy eyes, only nine (15.3%) had more than 50 CFU per plate, while in the group of dogs with corneal ulcer, 23 (62.2%) of the 37 isolates presented more than 50 CFU per plate. In both groups Gram-positive bacteria (86.5%) predominated over Gram-negative (13.5%). Staphylococcus spp. was the most frequently isolated genus and S. intermedius predominated in both groups. CONCLUSION: The results of our study are directly applicable to initiate rational, preventive and therapeutic measures with greater accuracy in dogs with corneal ulcer.     

Comparison of pharmacodynamic and pharmacokinetic indices of efficacy for 5 fluoroquinolones toward pathogens of dogs and cats

BACKGROUND: Fluoroquinolones are often used interchangeably in dogs and cats. HYPOTHESIS: Predicted therapeutic efficacy differs among fluoroquinolones. ANIMALS: Bacterial pathogens isolated from dogs and cats. METHODS: Using microtube-dilution procedures, percent resistance and 2 pharmacodynamic/pharmacokinetic indices (maximum concentration/minimum inhibitory concentration [Cmax/MIC] [target 0.10] and area under curve/minimum inhibitory concentration [AUC/MIC] [target 0.125]) were compared prospectively at low and high doses (mg/kg) for ciprofloxacin (5 and 20), difloxacin (5 and 10), enrofloxacin (including enrofloxacin+ciprofloxacin) (5 and 20), marbofloxacin (2.5 and 5), and orbifloxacin (2.5 and 7.5). Indices were calculated for organisms represented by < or = 15 isolates. RESULTS: Percent resistance for all Gram-negative (n = 180; 20+/-3%; 39+/-5% for Escherichia coli) and Gram-positive isolates (n = 66; 18+/-3%) did not differ among drugs or organisms. The pattern of Cmax/MIC was generally enrofloxacin+ciprofloxacin > or = enrofloxacin or ciprofloxacin > or = marbofloxacin > or = orbifloxacin > or = difloxacin; and for AUIC/ MIC, enrofloxacin+ciprofloxacin > or = marbofloxacin > or = ciprofloxacin > or = enrofloxacin > difloxacin > orbifloxacin. Among susceptible Gram-negative isolates studied (n = 117), targeted Cmax/MIC or AUC/MIC were achieved in 88% of E. coli, 53% of Proteus mirabilis, and 35% of Pseudomonas aeruginosa; and for susceptible Gram-positive isolates studied (n = 49), 53% of Streptotoccus spp. and Staphylococcus intermedius and 27% of Staphylococcus spp. At the high dose, the proportion of isolates for which a target was reached was: ciprofloxacin, enrofloxacin+ciprofloaxin, and marbofloxacin (77%), enrofloxacin (73%), orbifloxacin (51%), and difloxacin (40%); and at the low dose, enrofloxacin+ciprofloxacin and enrofloxacin (43%), ciprofloxacin (40%), marbofloxacin (39%), orbifloxacin (29%), and difloxacin (28%). CONCLUSIONS: E. coli resistance to fluoroquinolones approximated 40%. For susceptible isolates, enrofloxacin, marbofloxacin, and ciprofloxacin more consistently reached indices associated with predicted efficacy, but only at the high dose.     

Trends in fluoroquinolone resistance of bacteria isolated from canine urinary tracts.

Fluoroquinolone (FQ) antimicrobial agents are used extensively in human and veterinary medicine. Widespread use of any antimicrobial agent can apply selective pressure on populations of bacteria, which may result in an increase in the prevalence of antimicrobial-resistant isolates. Antimicrobial-susceptibility data on bacteria isolated from the canine urinary tract by the University of Missouri-Columbia Veterinary Medical Diagnostic Laboratory, Columbia, MO, were used to determine whether there has been an increase in the prevalence of FQ-resistant bacteria over time. Between January 1992 and December 2001, minimum inhibitory concentrations of either ciprofloxacin (1992-1998) or enrofloxacin (1998-2001) were determined for 1,478 bacterial isolates from the canine urinary tract. The predominant bacterial species isolated were Escherichia coli (547 isolates), Proteus mirabilis (156), and Staphylococcus intermedius (147). In all, there were 13 bacterial species with more than 25 isolates each. A significant increase in the overall proportion of resistant bacterial isolates was documented from 1992 to 2001 (Cochran-Armitage test for trend, P < 0.0001). The same increase in resistant isolates was documented when either ciprofloxacin or enrofloxacin was analyzed separately (P < 0.0001 and P < 0.0002, respectively). No difference was detected in rates of bacterial FQ resistance with regard to the sex of the dog from which the bacteria were isolated. The frequency with which some bacterial species were isolated differed with the sex of the infected dog. Proteus mirabilis was found more often in females (P < 0.0001), whereas beta hemolytic Streptococcus spp., were found more often in males (P = 0.0003). Although the overall efficacy of FQ antimicrobials remained high with greater than 80% of isolates being susceptible, the data demonstrated an increase in the proportion of resistant bacteria isolated from the urinary tract of the dog.     

Antimicrobial resistance of feline staphylococci in south-eastern England

Staphylococcus aureus is reported as the predominant feline staphylococcal pathogen. There is concern that cats may transfer resistant staphylococci to humans. In this study, staphylococci were obtained from skin and mucosae of 20 domestic cats, 9 with lesions, and 10 healthy feral cats. Species were identified by DNase and API ID32 Staph tests. Of 187 isolates, 21.4% were coagulase-positive and predominately from lesional cats; 90% of these were Staphylococcus intermedius . Coagulase-negative species were isolated equally in all three groups. All isolates were susceptible to coamoxiclav, cephalexin and bacitracin. Twenty-two, including 18 coagulase-negative isolates, showed some resistance to cotrimoxazole, lincomycin, enrofloxacin or oxytetracycline. Two isolates were resistant to more than one antibiotic. More resistant isolates were obtained from feral cats ( P < 0.01). The results suggest that S. intermedius is the principal coagulase-positive species. Antibiotic resistance is generally low amongst feline staphylococci. Higher resistance amongst feral cats suggests exposure to environmental antibiotics.     

Antimicrobial susceptibility of bacteria isolated from neonatal foal samples submitted to a New Zealand veterinary pathology laboratory (2004 to 2013)

AIMS: To describe antimicrobial susceptibility, and identify antimicrobial resistance (AMR), in bacteria isolated from New Zealand foals.

METHODS: A database search was performed of submissions to a veterinary pathology laboratory between April 2004 and December 2013 for bacterial culture of samples from foals <3 weeks of age. Culture and susceptibility results were compiled with demographic information. Susceptibility results were as defined for the Kirby-Bauer disk diffusion susceptibility test based on Clinical Laboratory Standards Institute guidelines. Multi-drug resistance (MDR) was defined as non-susceptibility to ≥3 of a panel of antimicrobials (ceftiofur, enrofloxaxin, gentamicin, penicillin, tetracycline, trimethoprim-sulfonamide); penicillin susceptibility was not included for Gram-negative isolates.

RESULTS: Submissions from 102 foals were examined, and 127 bacterial isolates were cultured from 64 (63%) foals. Of the 127 isolates, 32 (25%) were Streptococcus spp., 30 (24%) were Staphylococcus spp., 12 (10%) were Enterococcus spp. and 26 (21%) were Escherichia coli. Of 83 Gram-positive isolates, 57 (69%) were susceptible to penicillin. Over all isolates, 92/126 (73%) were susceptible to gentamicin and 117/126 (93%) to enrofloxacin; 62/82 (76%) of Gram-positive, and 22/42 (52%) of Gram-negative bacteria were susceptible to ceftiofur; 53/81 (65%) of Gram-positive, and 23/44 (52%) of Gram-negative bacteria were susceptible to tetracycline; 59/82 (72%) of Gram-positive, and 23/44 (43%) of Gram-negative bacteria were susceptible to trimethoprim-sulfonamide. Of 126 isolates, 33 (26%) had MDR; >1 isolate with MDR was cultured from 24/64 (38%) foals, and ≥2 isolates with MDR were recovered from 8/64 (13%) foals.

CONCLUSIONS: Multi-drug resistance, including resistance to commonly used antimicrobials, was found in bacterial isolates from foals in New Zealand.

CLINICAL RELEVANCE: The results of this study are of concern from a treatment perspective as they indicate a potential for antimicrobial treatment failure. For future surveillance of AMR and the creation of national guidelines, it is important to record more data on samples submitted for bacterial culture.     

Blood culture isolates and antimicrobial sensitivities from 427 critically ill neonatal foals

OBJECTIVE: To assist correct decision-making about antimicrobial treatment of equine neonates with septicaemia. DESIGN: Retrospective study of microbial blood culture results obtained from foals less than 7 days of age. METHODS: Microbial blood culture results from foals less than 7 days of age admitted to an intensive care unit between July 1999 and December 2004 were reviewed. Antimicrobial sensitivity was assessed by the Kirby Bauer disc diffusion method. Antimicrobials were defined as an effective first-line choice antimicrobial if greater than 70% of isolates were susceptible. Multiple drug resistance (MDR) was defined as resistance to at least three antimicrobials in different chemical classes or with different mechanisms of resistance. RESULTS: Of the 427 Thoroughbred foals included in the study, a positive blood culture was obtained in 110 foals and 124 microorganisms were isolated. Gram-positive isolates, predominantly Streptococcus/Enterococcus spp, were obtained in 41% of foals. Gram-negative isolates were predominantly of the Enterobacteriaceae family, in particular Escherichia coli. The overall antimicrobial sensitivity of the isolates was low. The Gram-positive organisms had unpredictable sensitivity patterns. MDR was recorded in 32% of isolates. In total, 81% of foals were discharged from hospital and 74.5% of foals with a positive blood culture were discharged. CONCLUSION: With the increasing prevalence of Gram-positive microorganisms and their unpredictable sensitivity patterns, blood cultures remain important in the diagnosis and treatment of equine neonatal septicaemia.     

Antimicrobial susceptibility of bacterial isolates from 233 horses with musculoskeletal infection during 1979-1989.

Bacterial culture and susceptibility results were analysed from 233 horses with septic arthritis/tenosynovitis or osteomyelitis that developed after fracture repair. Antibiotics were deemed highly effective, effective or ineffective if > or = 85%, 70-84.9% or < 70% of the isolates were susceptible respectively. In total, 424 bacterial types were isolated; 386 were aerobic or facultative and 38 were anaerobic. Enterobacteriaceae (28.8%) were the most common bacterial group isolated, followed by non-beta-haemolytic streptococci (13.0%), coagulase-positive staphylococci (11.8%), beta-haemolytic streptococci (9.4%), and coagulase-negative staphylococci (7.3%). The remainder of the organisms were other Gram-negative (15.8%), other Gram-positive (2.3%) and miscellaneous (2.6%) bacteria. Penicillin and ampicillin were highly effective against beta-haemolytic streptococci, but were ineffective against other bacteria. Ampicillin was no more effective than penicillin against most bacteria. Amikacin was the most effective antibiotic against the wide range of bacteria isolated in this study. Amikacin was highly effective against coagulase-positive staphylococci, Enterobacteriaceae and Pseudomonas and was effective against coagulase-negative staphylococci and Actinobacillus. Gentamycin was not highly effective against any bacterial group; but was effective against coagulase-positive and negative staphylococci, Pseudomonas, Salmonella and Actinobacillus. Kanamycin was ineffective against all bacteria with the exception of Actinobacillus. Cephalothin was highly effective against beta-haemolytic streptococci, coagulase-positive staphylococci and Actinobacillus and was effective against coagulase-negative staphylococci.(ABSTRACT TRUNCATED AT 250 WORDS)     

西宁地区犬呼吸道菌群分析及药敏试验

犬类呼吸道疾病是宠物犬常见病,严重者导致犬只死亡。但是,目前在临床上该病用药缺乏科学指导。本实验采集了西宁地区5家宠物医院共63例健康犬及92例呼吸道患病犬的标本,进行呼吸道多菌群的分离培养、染色镜检和全自动微生物分析仪鉴定,并对检出菌进行了Kirby-Bauer纸片扩散法药敏试验。结果发现,犬呼吸道正常菌群有缓慢葡萄球菌、放射根瘤菌、少动鞘氨醇单胞菌等;主要致病菌有金黄色葡萄球菌、肺炎克雷伯菌臭鼻亚种。通过对所有样品的菌株分离发现犬上呼吸道是以革兰阳性菌偏多,阳性菌株分离率(65.9%),阴性菌株分离率(34.1%)。药敏试验结果显示,革兰阳性细菌敏感的药物为头孢噻肟、头孢曲松,敏感率>50%。革兰阴性细菌敏感的药物为恩诺沙星、丁胺卡那,敏感率>70%。同时,两类菌群对阿莫西林、林可霉素都有明显的耐药性(耐药率>70%)。     

Aerobic bacterial flora of nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica.

Bacteriological examination of 70 nesting green turtles (Chelonia mydas) from Tortuguero National Park, Costa Rica was performed to investigate nasal and cloacal aerobic bacteria. A total of 325 bacterial isolates were obtained, including 10 Gram-negative and three Gram-positive genera. Two hundred thirty-nine were Gram-negative and 86 were Gram-positive isolates. Klebsiella pneumoniae was the most common microbe identified in turtle samples: 27/70 (38.5%) in cloacal, and 33/70 (47.1%) in nasal samples. The Enterobacteriaceae family, including Enterobacter agglomerans, E. cloacae, Escherichia coli, Klebsiella oxytoca, K. pneumoniae, and Serratia marcescens, was the largest Gram-negative group of bacteria recovered and comprised 127 of 239 (53.1%) of the Gram-negative isolates. Staphylococcus species was the largest Gram-positive bacteria group, including S. aureus, S. cromogenes, S. epidermis, and S. intermedius, and made up 63 of 86 (73.2%) of the Gram-positive isolates recovered. The results of this study demonstrate that the aerobic bacterial flora of nesting green turtles at Tortuguero National Park is composed of a very wide spectrum of bacteria, including several potential pathogens.     

Bacteremia in equine neonatal diarrhea: a retrospective study (1990-2007)

Background: Bacteremia in sick foals is associated with survival, but the association of bacteremia and diarrhea is not reported.
Hypothesis: Neonatal foals with diarrhea will commonly be bacteremic.
Animals: One hundred and thirty-three neonatal foals.
Methods: Records of all foals <30 days of age presenting with diarrhea between January 1990 and September 2007 were reviewed.
Results: Sixty-six of 133 foals (50%) were bacteremic at admission, with 75 isolates from the 66 samples. The blood culture from a further 18 foals (13.5%) grew coryneform bacteria. Nine foals (6.8%) had 2 or more organisms grown on blood culture. One foal had 5 different organisms, interpreted as contamination. Forty-eight foals (36%) had no growth on admission blood cultures. No cultures isolated fungal organisms. Excluding coryneform bacteria, 43 isolates (57%) were Gram-negative organisms and 32 isolates (43%) were Gram-positive organisms. The most common isolate was Enterococcus spp. (22 isolates, 29%), followed by Pantoea agglomerans (13 isolates, 17%). IgG concentration at admission was not associated with blood culture status. Blood culture status was not associated with survival to hospital discharge.
Conclusions and Clinical Importance: Bacteremia is common in neonatal foals with diarrhea. Decisions regarding antimicrobial selection should be made with these differences in mind.