The occurrence and significance of plasma coagulase negative staphylococci from the genital tract of horses

Classification based on biochemical characteristics of 389 strains of plasma-coagulase-negative (plc-) staphylococci isolated from the genital tract of mares and stallions resulted in the following distribution of species: St. sciuri 130 (33.4%), St. equorum 42 (10.8%), St. xylosus 16 (4.1%), St. epidermidis 35 (9.0%), St. simulans 24 (6.2%), St. haemolyticus 33 (8.5%), St. warneri 18 (4.6%), St. lentus 12 (3.1%), St. hyicus 11 (2.8%). Strains of St. cohnii, St. capitis, St. gallinarum, St. saprophyticus and St. hominis have only been found sporadically (a. 1%). 48 (12.3%) strains could not be classified. With regard to species distribution of isolates from stallions and mares. 63.7% of the isolates from stallions belonged to St. sciuri and 9.3% to St. lentus, whereas in isolates of mares these species numbered only 24.9% and 0.4%, respectively. On the other hand the species St. equorum (14.9% vs. 6.8%), St. epidermidis (14.5% vs. 1.7%), St. haemolyticus (14.0% vs. 1.7%), St. warneri (7.7% vs. 0.8%) and St. xylosus (5.9% vs. 2.5%) predominated in mares. St. simulans was found occurring equally in mares and stallions (7.7% vs. 5.9%). Comparing the staphylococcal species of healthy mares and of mares which have not become pregnant after copulation no indication was found for a significant role of certain plc- staphylococci in infertility. All of the 389 isolates were tested for production of protein A, i.e. Fc-fragment binding receptors, using a microenzyme-assay with peroxidase-labelled rabbit immunoglobulin G. With this method cell-bound or extracellular Fc-receptors could not be detected in anyone of the plc- staphylococcal strains.(ABSTRACT TRUNCATED AT 250 WORDS)     

Identification of clumping-factor-negative staphylococci isolated from cows' udders

Identification to species level was attempted on a collection of 954 cultures of catalase-positive, clumping-factor- and beta-haemolysin-negative Gram-positive cocci isolated from teats and milk of cows. Eighty-seven per cent of the strains were identified as Staphylococcus xylosus, S epidermidis, S sciuri, S haemolyticus, S hyicus subsp hyicus and chromogenes, S simulans and S cohnii. Nine per cent of the collection belonged to another group which could not be identified with any of the known Staphylococcus species. Many of the strains of this group and also part of the S epidermidis and S hyicus subsp chromogenes strains examined showed various degrees of growth enhancement on certain media when fatty substances were added. Only nine strains were classified as Micrococcus. A scheme for the identification of coagulase-negative staphylococci from cows' milk is proposed.     

Staphylococci isolated from healthy goats.

A study was made of the staphylococcal population on the skin and on the nasal mucosa and in the milk of 133 healthy goats. Of a total of 346 strains isolated and characterised as belonging to the genus Staphylococcus, 74 (21.4%) were coagulase-positive (68 S. aureus and 6 S. hyicus), and 272 (78.6%) coagulase-negative. The novobiocin-sensitive species S. haemolyticus (23.5%), S. warneri (16.5%), S. epidermidis (11.8%), S. chromogenes (8.5%), S. caprae (6.6%) and S. hyicus (2.6%), and the novobiocin-resistant species S. xylosus (8.5%), S. sciuri (7.4%), S. saprophyticus (4.8%), S. cohnii (2.2%), S. lentus (1.1%), S. equorum (1.1%) and S. kloosii (1.1%) were identified. Twelve (4.4%) of coagulase-negative strains remained unidentified. Strains isolated in the skin of the udder and teats of the 133 goats were mainly novobiocin-sensitive coagulase-negative staphylococci, the most prevalent species being S. haemolyticus, S. warneri and S. epidermidis. Staphylococci indicative of subclinical infection were determined in the milk of 47 (35.3%) of the 133 goats sampled.     

Coagulase negative staphylococci isolated from cow milk

The species composition was determined in the set of 52 randomly selected strains of coagulase-negative staphylococci, which were isolated from the milk of dairy cows in 1989. Of this set of strains, the following species were identified: Staphylococcus hyicus subsp. chromogenes (26.9% strains of the set), S. hyicus subsp. hyicus (10.3%), S. xylosus (19.3%), S. saprophyticus (11.5%), S. warneri (9.6%), S. haemolyticus (9.6%), S. hominis (3.8%). Attention is drawn to the increasing occurrence and significance of coagulase-negative staphylococci from the point of view of mastitis in dairy cows.     

A bacteriologic study of scabby-hip lesions from broiler chickens in Texas

Broilers from commercial flocks experiencing a 10-60% incidence of scabby-hip lesions at processing were examined, and selected skin lesions were cultured. Over 70% of the lesions were associated with traumatic excoriations, particularly on the caudal dorsal convexity of the birds. Most lesions were observed on birds that were 5 weeks of age or older. From the 27 specimens cultured, Clostridium perfringens was isolated in pure culture from 4 lesions and Staphylococcus species from 10 lesions. Pure cultures of staphylococci were recovered from 4 lesions, and 2-5 different staphylococci were isolated from 6 lesions. Eight staphylococci were identified as S. sciuri, 8 as S. simulans, 2 as S. epidermidis, 2 as S. lentus, 2 as S. warneri, 1 as S. cohnii, and 1 as S. intermedius. Fifty cutaneous specimens from 10 5-week-old normal broilers were cultured. A total of 197 isolates were identified including 65 S. sciuri, 52 S. lentus, 24 S. simulans, 12 S. hyicus, 11 S. warneri, 9 S. cohnii, 9 S. gallinarium, 8 S. xylosus, and 7 S. epidermidis.     

Prevalence and persistence of coagulase-negative Staphylococcus species in three dairy research herds

Coagulase-negative Staphylococcus species (CNS) were isolated from 11.3% (1407 of 12,412) of mammary quarter milk samples obtained from cows in three dairy research herds in 2005. Approximately 27% (383/1407) of CNS was identified to the species level. The species distribution among those CNS identified from all herds was Staphylococcus chromogenes (48%), Staphylococcus hyicus (26%), Staphylococcus epidermidis (10%), Staphylococcus simulans (7%), Staphylococcus warneri (2%), Staphylococcus hominis (2%), Staphylococcus saprophyticus (1%), Staphylococcus xylosus (1%), Staphylococcus haemolyticus (<1%), Staphylococcus sciuri (<1%), and Staphylococcus intermedius (<1%). Staphylococcuschromogenes was the predominant CNS isolated from all three herds; however, differences were seen in the prevalence of other CNS species. A total of 158 CNS (S. chromogenesn=66, S. hyicusn=38, S. epidermidisn=37, S. simulans n=10, and S. warneri n=7) were analyzed by pulsed-field gel electrophoresis (PFGE). The majority (33/41) of CNS isolated from the same mammary quarter on more than one occasion had the same PFGE pattern indicating persistence of the same infection over time. When all PFGE patterns for each CNS were analyzed, no common pulsotype was seen among the three herds indicating that CNS are quite diverse. Composite milk somatic cell count (SCC) data were obtained +/-14d of when CNS were isolated. Average milk SCC (5.32 log(10)/ml) for cows in which CNS was the only bacteria isolated was significantly higher than the average milk SCC (4.90 log(10)/ml) from cows with quarter milk samples that were bacteriologically negative.     

Haemolytic and proteolytic activity of coagulase-negative staphylococci isolated from mastitis cows

The aim of the present study was to assess the haemolytic and proteolytic activity of coagulase-negative staphylococci (CNS) isolated from cows with mastitis. The study was conducted on 100 CNS strains: S. xylosus (n=28), S. chromogenes (n=26), S. haemolyticus (n=25), S. sciuri (n=14), S. warneri (n=4), S. hominis (n=2), S. saprophyticus (n=1); 22 CNS were isolated from cows with clinical mastitis and 78 from those with subclinical mastitis. The CNS studied showed the ability to produce only alpha-haemolysin and belonged to one strain - S. haemolyticus (21.0% of isolated CNS strains). Haemolysin-positive CNS were responsible for both clinical and subclinical mastitis (22.7% and 20.5%, respectively). The ability to produce protease was found in 31.0% of CNS belonging to two strains: S. chromogenes and S. sciuri. Protease-positive CNS were the etiological factor of both clinical and subclinical mastitis (31.8% and 30.8%, respectively). All S. xylosus, S. warneri, S. hominis, and S. saprophyticus strains were found protease-negative and haemolysin-negative, irrespective of whether they caused clinical or subclinical mastitis in cows.     

Bacterial flora of the conjunctiva and nasal cavity in normal and diseased captive bustards.

A survey was carried out to describe the normal aerobic bacterial flora of the conjunctiva and nasal cavity of captive houbara bustards (Chlamydotis undulata), kori bustards (Ardeotis kori), and white-bellied bustards (Eupodotis senegalensis) maintained at the National Avian Research Center, Abu Dhabi, United Arab Emirates. A total of 58 samples were examined from the nasal cavity and 55 samples from the conjunctiva of healthy bustards. There was no bacterial growth in 45% of conjunctival samples. Bacteria isolated from the conjunctiva of healthy birds included Micrococcus spp., Staphylococcus auricularis, Staphylococcus xylosus, Staphylococcus capitis, Staphylococcus warneri, Bacillus spp., and Enterobacter amigenus. Bacteria isolated from the nasal cavity of healthy birds included Bacillus spp., Micrococcus spp., S. auricularis, S. xylosus, Staphylococcus simulans, Staphylococcus saprophyticus, Staphylococcus hyicus, Staphylococcus cohnii, Staphylococcus sciuri, Aerococcus spp., and Providencia rettgeri. These findings were compared with bacterial isolates from bustards with clinical signs of ocular or upper respiratory tract diseases. Mycoplasma spp., Pseudomonas aeruginosa, Pseudomonas stutzeri, Proteus mirabilis, Escherichia coli, Klebsiella spp., Aeromonas hydrophila, and Staphylococcus aureus were the pathogenic bacteria isolated from the conjunctiva of 34.3% bustards with ocular discharges. Mycoplasma spp., P. aeruginosa, Pseudomonas spp., P. mirabilis, E. coli, Klebsiella pneumoniae, and S. aureus were the pathogenic bacteria isolated from the nasal cavity of 74% bustards with upper respiratory tract diseases.     

Resistance patterns of ovine mastitis pathogens]

For control of the udder health status of milk sheep the minimal inhibitory concentration of mastitis causing pathogens to 12 different chemotherapeutics was determined by means of Sensititre microplate method. 73 staphylococci- and 8 streptococci-strains was examined. Following staphylococci-strains were found: S. aureus (11), S. epidermidis (34), S. chromogenes and S. xylosus (6 each), S. hyicus and S. warneri (each 5) as well as S. sciuri and S. simulans (3 each). MIC-values to penicillin, amoxycillin and ampicillin of 2 penicillinase-positive S. aureus-strains were more than 4.0 micrograms/ml. The remaining isolates and the major part of coagulase-negative staphylococci displayed MIC-values up to 1.0 microgram/ml to beta-lactamantibiotics except cloxacillin. Against cephalosporines, cephalexin excluded, and aminoglycosides very low MIC-values concerning staphylococci were observed. In case of spiramycin MIC-levels more or less than 8.0 micrograms/ml were determined. Streptococci exhibited MIC-values in the range of 0.06 to 0.5 microgram/ml against beta-lactamantibiotics with exclusion of cloxacillin, cefoperazone and cefquinome and spiramycin as well.     

Genotypic versus phenotypic identification of staphylococcal species of canine origin with special reference to Staphylococcus schleiferi subsp. coagulans

A comparative study was performed to examine the respective accuracy of 16S rDNA sequencing and of the commercial biochemical assay ID32 STAPH (bioMérieux, Marcy l'Etoile, France) in the identification of 232 staphylococcal samples representing 20 species and subspecies isolated from 367 dogs. Notable differences in species distribution were observed by comparing genotypic and phenotypic data. Partial sequencing of 16S rDNA resulted in an unambiguous identification of 226 (97.4%) of the isolates, whereas the phenotypic approach resulted in a correct diagnosis of 162 (69.8%) of the isolates. Statistical agreement between genotypic and phenotypic identification of staphylococci was substantial (Kappa coefficient of 0.6-0.8) for Staphylococcus aureus, S. hominis, S. warneri, S. cohnii subsp. urealyticus, and S. simulans, and "almost perfect" (Kappa coefficient of 0.8-1) for S. intermedius, S. epidermidis, S. equorum, S. haemolyticus, S. sciuri, and S. kloosi. No agreement above that expected by chance (Kappa coefficient=0) was observed for S. schleiferi subsp. coagulans, which was either confounded with S. intermedius and S. capitis, or categorized as unacceptable by the biochemical assay. Given the growing importance of this pathogen in veterinary medicine and its frequent misidentification with related staphylococci, a PCR-RFLP approach producing a S. schleiferi-specific restriction profile was developed. This fast and reliable assay represents a valuable tool in assisting in the monitoring of this pathogen.     

Identification of staphylococci from bovine mastitis and an examination of their susceptibility to antibiotics and beta-lactamase production

Strains of Staphylococcus species isolated from bovine mastitic milk at 66 dairy farms in Japan during the period from November 1988 to May 1989 were identified, and examined for their drug susceptibility and beta-lactamase production in order to clarify an epidemiological aspect of bovine mastitis caused by staphylococci. The results of bacteriological identification showed that the most predominant species was S. xylosus. Other major species isolated were S. aureus, S. sciuri and S. hyicus. Thirty-eight (71.7%) isolates of S. xylosus, 21 (45.7%) of S. aureus and 5 (71.4%) of S. epidermidis were positive for beta-lactamase production. Most of the beta-lactamase-producers of S. aureus were classified as high producers, although all of the beta-lactamase-positive S. xylosus isolates remained to be low producers. All isolates of S. aureus were sensitive to methicillin and cloxacillin at 6.25 micrograms/ml and 1.56 micrograms/ml, respectively, and none of methicillin-resistant S. aureus were detected. Isolates of other species were considered to be susceptible to 6 beta-lactams, in contrast to human isolates, but antibacterial activities of penicillin G and ampicillin were affected more strongly by beta-lactamase than those of methicillin, cloxacillin, cefazolin and cefoperazone.     

Methicillin-resistant coagulase-negative staphylococci isolated from healthy horses in Japan

OBJECTIVE: To determine patterns of methicillin-resistant staphylococci isolated from apparently healthy horses. SAMPLE POPULATION: 44 horses from 8 riding clubs in Japan. PROCEDURE: Methicill in-resistant staphylococci were isolated from the skin or nares, using a selective medium containing a beta-(symboric) lactam antibiotic, ceftizoxime. Clonality of isolates was determined by use of pulsed-field gel electrophoresis. Detection of mecA, mecl, and mecR1 genes was accomplished by use of polymerase chain reactions. RESULT: Of the 44 horses, 13 (29.5%) yielded 15 isolates of methicillin-resistant staphylococci. The 15 isolates were identified as 6 species (Staphylococcus epidermidis, S lentus, S saprophyticus, S xylosus, S sciuri, and S haemolyticus). However, methicillin-resistant S aureus was seldom isolated. Each isolate contained the mecA gene and had a high resistance to beta-lactam antibiotics. Some isolates also were resistant to other antibiotics such as erythromycin and kanamycin. CONCLUSIONS AND CLINICAL RELEVANCE: Methicillin-resistant coagulase-negative staphylococci that were highly resistant to various antibiotics were isolated from apparently healthy horses in Japan. These organisms must be considered a potential threat to horses and veterinarians who care for them.     

Frequency and antimicrobial susceptibility of Staphylococcus spp isolated from feline skin lesions

Swab specimens obtained from skin lesions of 45 cats were cultured bacteriologically for staphylococci. Thirty-two staphylococcal isolates were recovered from 30 cats and were biotyped, using biochemical tests contained in a staphylococcal identification system. Of 23 isolates considered coagulase-positive, 16 were identified as Staphylococcus aureus, 5 as S intermedius, and 2 as S hyicus. Of 9 isolates considered coagulase-negative, 6 were identified as S simulans, 2 as S epidermidis, and 1 as S xylosus. Antimicrobial susceptibility tests were done on all staphylococcal isolates, using a disk-diffusion method. Staphylococcal isolates were susceptible to clavulanic acid-amoxicillin, cloxacillin, cephalothin, chloramphenicol, gentamicin, erythromycin, and trimethoprim-sulfamethoxazole. Resistance to penicillin G, ampicillin, and tetracycline was frequent.     

Isolation and species distribution of staphylococci from animal and human skin

From April 1999 to December 2000, a survey was made on the distribution of Staphylococcus species on the skin of 7 kinds of animals and humans. Staphylococci were isolated from 12 (100%) of 12 pigs, 17 (89.5%) of 19 horses, 30 (100%) of 30 cows, 73 (90.1%) of 81 chickens, 10 (40%) of 25 dogs, 23 (76.7%) of 30 laboratory mice, 20 (52.6%) of 38 pigeons, and 80 (88.9%) of 90 human beings. The predominant staphylococci isolated from a variety of animal species were novobiocin-resistant species, S. xylosus and S. sciuri regardless of the animal host species. The novobiocin-resistant species including S. xylosus and S. sciuri were only occasionally isolated from human skin. The predominant staphylococci found on human skin were novobiocin-sensitive species, S. epidermidis (63.8%), followed by S. warneri (28.8%) and S. hominis (13.8%). The results suggest that the staphylococcal flora inhabiting animal skin are different from those of human skin in regard to the predominant species isolated. In this study, we used pulsed-field gel electrophoresis to examine the chromosomal polymorphisms of S. epidermidis isolated most frequently from human skin. Strains of S. epidermidis showed the greatest genomic diversity in their fragment patterns.     

Species identification and some characteristics of coagulase-negative staphylococci isolated from bovine udders.

The species of 203 strains of coagulase-negative staphylococci (CNS), isolated from bovine udder quarters was determined; all were tested for hydrophobicity and encapsulation, attributes that may relate to virulence. Twelve species were identified, of which Staphylococcus simulans, (34.5%), S. chromogenes (16.7%), S. epidermidis (13.8%) and S. xylosus (8.9%) were the most frequent. The majority of strains possessed a hydrophilic cell surface. However, strains from two species (S. chromogenes and S. epidermidis) were more hydrophobic than the others. Only five strains were encapsulated (S. xylosus, 3; S. saprophyticus, 1; and S. sciuri, 1). Judging from the low frequencies of hydrophobic and encapsulated strains, and comparing with strains isolated from clinical cases, it is suggested that these properties are not major virulence determinants of CNS.     

Characterization of staphylococci associated with clinical and subclinical bovine mastitis

Attempts were made to identify 900 species of staphylococci or micrococci recovered from samples of bovine milk examined for mastitis pathogens. The presence and identity of haemolysins was recorded together with results of disc diffusion antibiotic sensitivity tests. The occurrence of clinical mastitis was also noted and somatic cell counts (SCC) were performed on milk samples which were normal in appearance. Eight hundred and thirty-one coagulase positive staphylococci were obtained, of which 810 were S. aureus and 21 were S. intermedius. Of 65 coagulase negative staphylococci the species of 19 could not be determined by the identification systems used. The remainder were identified as S. hyicus sub sp. hyicus (1), S. hyicus sub sp. chromogenes (19), S. haemolyticus (17), S. hominis (3), S. epidermidis (4), S. capitis (1) and either S. hominis or S. warneri (1). Four other isolates could not clearly be assigned to the genus Staphylococcus or Micrococcus and were designated irregular strains. No micrococci were identified. The presence of alpha, beta, or delta haemolysins occurring singly or in various combinations was identified in 98.3% of coagulase positive staphylococci and in 60% of coagulase negative staphylococci. Epsilon haemolysin was detected in 47.6% of the coagulase negative staphylococci and in 9.5% of S. intermedius. All staphylococci were sensitive to tetracycline (30 microg), novobiocin (1.6 microg), nafcillin (30 microg), methicillin (10 microg) and cephalothin (30 microg) and variable numbers of each species were sensitive to penicillin (2 iu) and streptomycin (10 microg). One non-identified species of coagulase negative staphylococcus was sensitive to erythromycin (0.4 microg) the remaining staphylococci were resistant. Each of the four irregular strains was sensitive to erythromycin and novobiocin. Clinical mastitis was associated with 30.6% of coagulase positive staphylococci, 15.3% of coagulase negative staphylococci, and two of the four irregular strains (50%). Subclinical mastitis as determined by SCC of 500 x 10(3) or greater was associated with 92.7% of coagulase positive and 37.5% of coagulase negative staphylococci.     

Species of Staphylococcus isolated from animal infections

One hundred randomly selected clinical strains of staphylococci were identified by species using a commercial micromethod system. Eight species of staphylococci were identified. Staphylococcus intermedius was the most frequent (n = 74) species identified and accounted for 70/74 (94.6%) of the coagulase-positive strains and 70/79 (88.6%) of the total isolates from dogs. Other species identified, in order of their frequency, included S. epidermidis (8), S. aureus (7), S. simulans (4), S. sciuri (2), S. xylosus (2), S. hyicus (2) and S. saprophyticus (1). These results show that at least 8 different species of staphylococci can be recovered from animal infections and that coagulase-positive species such as S. intermedius may be more common than S. aureus. The relative significance of these other species in animal infections needs to be assessed.     

A comparison of the STAPH-Ident and STAPH-Trac systems to conventional methods in the identification of staphylococci isolated from bovine udders

The STAPH-Ident and STAPH-Trac systems (Analytab Products, Plainview, N.Y.) were compared to conventional methods for identification of staphylococci isolated from bovine udders. The STAPH-Ident system identified 80.5% of isolates correctly. An additional 7.6% of Staphylococcus hyicus strains were delineated from S. epidermidis by characterizing acetoin and pigment production. Final accuracy of the STAPH-Ident system was 88.1%. The STAPH-Trac system identified 66.1% of isolates. Negative phosphatase tests for 42.3% of S. hyicus strains resulted in misidentification as S. simulans. Consequently, only 45.5% of S. hyicus isolates were identified correctly by the STAPH-Trac system. Minor modification of each system would permit accurate, rapid identification of staphylococci isolated from bovine udders.     

CNS species and antimicrobial resistance in clinical and subclinical bovine mastitis

Coagulase-negative staphylococci (CNS) are often associated with bovine mastitis. Knowledge about the relative importance of specific CNS species in different types of mastitis, and differences in antimicrobial resistance among CNS species is, however, scarce. Therefore, the aims of this study were to compare prevalence and antimicrobial susceptibility of CNS species in clinical and subclinical mastitis using material from two national surveys. Overall, Staphylococcus chromogenes and Staphylococcus epidermidis were the most common CNS species found followed by Staphylococcus simulans and Staphylococcus haemolyticus. S. epidermidis was significantly more prevalent in subclinical than in clinical mastitis, and a similar trend was observed for Staphylococcus saprophyticus, while Staphylococcus hyicus was significantly more common in clinical mastitis. The prevalence of β-lactamase producing isolates varied markedly between CNS species, and was significantly higher in S. epidermidis and S. haemolyticus (～ 40%), than in S. simulans and S. chromogenes where none or a few of the isolates produced β-lactamase. Resistance to more than one antimicrobial substance occurred in 9% and 7% of the clinical and subclinical isolates, respectively. In conclusion, the distribution of CNS species differed between clinical and subclinical mastitis indicating inter-species variation of pathogenicity and epidemiology. Overall, the prevalence of antimicrobial resistance was low, but some variation between CNS species was observed.     

Frequency and antimicrobial susceptibility of Staphylococcus species isolated from canine pyodermas

Specimens obtained from pyogenic skin lesions of 210 dogs were culturally examined for staphylococci. A total of 215 isolates of staphylococci were biotyped, using the biochemical tests contained in a commercial staphylococcal identification system. Of 201 coagulase-positive isolates, 197 were identified as Staphylococcus intermedius, 3 as S aureus, and 1 as S hyicus. Of 14 coagulase-negative isolates, 5 were identified as S epidermidis, 5 as S xylosus, 3 as S simulans, and 1 as S hominis. Antimicrobial susceptibility tests were done on all staphylococcal isolates, using the standard disk-diffusion method. Staphylococcus intermedius isolates were susceptible to cephalothin, methicillin, and gentamicin. Resistance to ampicillin, penicillin G, and tetracycline was frequent. Antibiotic resistance was not associated with the depth of skin infection. Resistance to ampicillin, penicillin, tetracycline, and trimethoprim-sulfamethoxazole was not associated with previous antibiotic use. Increased resistance to chloramphenicol, clindamycin, and erythromycin was associated with previous antibiotic therapy. Antimicrobial susceptibilities of the other Staphylococcus species isolated are reported, but the small numbers of these species precluded making meaningful comparison with S intermedius.