Identification of pathogenic staphylococci isolated from animals and foods derived from animals

Prevalence and Characterization of Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus on Public Recreational Beaches in Northeast Ohio

Staphylococcus aureus can cause severe life-threatening illnesses such as sepsis and endocarditis. Although S. aureus has been isolated from marine water and intertidal beach sand, only a few studies have been conducted to assess prevalence of S. aureus at freshwater recreational beaches. As such, we aimed to determine prevalence and molecular characteristics of S. aureus in water and sand at 10 freshwater recreational beaches in Northeast Ohio, USA. Samples were analyzed using standard microbiology methods, and resulting isolates were typed by spa typing and multilocus sequence typing. The overall prevalence of S. aureus in sand and water samples was 22.8% (64/280). The prevalence of methicillin-resistant S. aureus (MRSA) was 8.2% (23/280). The highest prevalence was observed in summer (45.8%; 55/120) compared to fall (4.2%; 5/120) and spring (10.0%; 4/40). The overall prevalence of Panton-Valentine leukocidin genes among S. aureus isolates was 21.4% (15/70), and 27 different spa types were identified. The results of this study indicate that beach sand and freshwater of Northeast Ohio were contaminated with S. aureus, including MRSA. The high prevalence of S. aureus in summer months and presence of human-associated strains may indicate the possibility of role of human activity in S. aureus contamination of beach water and sand. While there are several possible routes for S. aureus contamination, S. aureus prevalence was higher in sites with wastewater treatment plants proximal to the beaches.

Inhibition of methicillin-resistant Staphylococcus aureus (MRSA) by antimicrobial peptides (AMPs) and plant essential oils

CONTEXT

Drug-resistant bacterial infections cause considerable patient mortality and morbidity. The annual frequency of deaths from methicillin-resistant Staphylococcus aureus (MRSA) has surpassed those caused by human immunodeficiency virus/acquired immune deficiency syndrome. The antimicrobial peptides (AMPs), plant essential oils (EOs) and their combinations have proven to be quite effective in killing a wide selection of bacterial pathogens including MRSA.

OBJECTIVES

This review summarizes the studies in the use of AMPs, plant EOs and their combinations for coping with MRSA bacteria, and to formulate new prospects for future studies on this topic.

METHODS

The sources of scientific literature such as PubMed, library search, Google Scholar, Science Direct and electronic databases such as 'The Antimicrobial Peptide Database', 'Collection of Anti-Microbial Peptides' and 'YADAMP'. Physicochemical data of anti-MRSA peptides were determined by Scientific DataBase Maker software.

RESULTS

Of the 118 peptides, 88 exhibited an activity against MRSA with the highest activity of minimum inhibitory concentration values. Various plant EOs have been effective against MRSA. Remarkably, lemongrass EOs completely inhibited all MRSA growth on the plate. Lemon myrtle, Mountain savory, Cinnamon bark and Melissa EOs showed a significant inhibition.

CONCLUSION

Several of these AMPs, EOs and their combinations were effective against MRSA. Their activities have implications for the development of new drugs for medical use.

Comparison of a chlorhexidine and a benzoyl peroxide shampoo as sole treatment in canine superficial pyoderma

The clinical and antibacterial efficacy of two shampoos used as a sole antibacterial treatment in dogs with superficial pyoderma were investigated and compared. In a randomised, partially blinded study, a 3 per cent chlorhexidine gluconate shampoo (Chlorhex 3; Leo Animal Health) was compared against a 2.5 per cent benzoyl peroxide shampoo (Paxcutol; Virbac) in 22 dogs with superficial pyoderma. Dogs were washed two to three times weekly with a 10-minute contact time over 21 days. Clinical scores and bacterial counts were assessed on days 1, 8 and 22 and compared within and between treatment groups; overall response was assessed at the end of the study. Twenty dogs completed the study; 15 (68.2 per cent) showed an overall clinical improvement and the clinical signs resolved in three chlorhexidine-treated dogs. In the chlorhexidine-treated group, scores for papules/pustules (P<0.001), investigator-assessed pruritus (P=0.003), total bacterial counts (P=0.003) and counts for coagulase-positive staphylococci (P=0.003) were reduced after three weeks. Scores and bacterial counts did not vary significantly in the benzoyl peroxide-treated group.

Emergence of methicillin-resistant Staphylococcus aureus (MRSA) in different animal species

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) in animals such as horses, pet animals and productive livestock has raised questions of a probable human origin and in more general of host specificity of S. aureus. Particular clonal lineages are obviously specific for humans (e.g. ST15, ST25, ST45) and other for ruminants (e.g. ST151). MRSA associated with veterinary nosocomial infections (e.g. ST8 and ST254 in horses, ST22 in small animals) very likely have their origin in health care facilities. MRSA ST398 which became first known from widespread colonization in industrially raised pigs seems to have a limited host specificity and is able to colonize and to cause infections in various hosts. Mechanisms of host adaptation and their genomic background are poorly understood so far.

Species identification of staphylococci and micrococci isolated from ewes' milk cheeses

Forty-five strains of staphylococci and 6 strains of micrococci isolated from pasteurized ewes' milk cheeses (Manchego and Burgos varieties) were identified to species level. Three strains of staphylococci were identified asStaphylococcus aureus. Amongst the 42 coagulase-negative staphylococci, 8 were novobiocin-sensitive and 34 novobiocin-resistant. The novobiocin-sensitive species found wereStaph. auricularis(5 strains),Staph. caseolyticus(2 strains) andStaph. epidermidis(1 strain). Novobiocin-resistant strains were identified asStaph. gallinarum(5 strains),Staph. xylosus(4),Staph. saprophyticus(9),Staph. cohnii(6),Staph. sciuri(1) andStaph. lentus(3). The other 6 isolates could not be identified. Only 3 strains of micrococci were identified (Micrococcus kristinae, M. variansandM. sedentarius). The possible origin of the isolates is discussed.

First report of multiresistant, mecA-positive Staphylococcus intermedius in Europe: 12 cases from a veterinary dermatology referral clinic in Germany

Resistance to cephalosporins and/or fluoroquinolones by Staphylococcus intermedius has remained low in Europe, with effective drugs generally available for systemic therapy in pets. However, multiresistant, mecA-positive S. intermedius isolated from dogs and cats is now emerging in Europe. Twelve S. intermedius isolates, highly resistant to at least five antimicrobial classes, were isolated from skin and ear infections in 11 dogs and a cat. The 12 isolates represented 23% of all S. intermedius submissions from one veterinary dermatology referral clinic in northern Germany to veterinary diagnostic laboratories during an 18-month period and resistance included cefalexin, methicillin and enrofloxacin. The animals had been referred to the clinic with recurrent superficial pyoderma, deep pyoderma, pododermatitis or chronic otitis, all unresponsive to systemic beta-lactam-antibiotics or fluoroquinolones. Infection resolved in 10 dogs and the cat on a combination of antimicrobial treatment and correction of underlying causes. Four dogs and a cat required systemic and topical therapy; in six dogs topical antimicrobial therapy alone was successful. Phenotypic and genotypic characteristics of the S. intermedius isolates were determined; species identification was confirmed by polymerase chain detection of thermonuclease genes (nuc) and the presence and expression of the gene conferring resistance to all beta-lactam antibiotics (mecA) were demonstrated in all; based on pulsed-field gel electrophoresis, six were indistinguishable, the others closely or possibly related. The emergence of multiresistant, mecA-positive S. intermedius in Europe is alarming. Zoonotic implications, awareness among veterinary laboratories and strategies for the use of antimicrobials in small animal practice need to be considered.

Staphylococcus pseudintermedius sp. nov., a coagulase-positive species from animals

Four staphylococcal isolates from clinical and necropsy specimens from a cat, a dog, a horse and a parrot (Psittacus erithacus timneh) were found to constitute a distinct taxon. 16S rRNA gene sequence analysis revealed that its closest phylogenetic relatives are Staphylococcus intermedius and Staphylococcus delphini. Growth characteristics, biochemical features and DNA-DNA hybridizations demonstrated that the strains differ from these and other known species and that they represent a single, novel Staphylococcus species for which the name Staphylococcus pseudintermedius sp. nov. is proposed. The novel species is commonly confused with S. intermedius in routine diagnostic veterinary bacteriology. Although the strains described were isolated from lesions and show several characteristics typical of pathogenic staphylococci, such as coagulase, DNase and beta-haemolysin production, the pathogenic significance of the novel species remains unclear. The type strain, LMG 22219(T) (=ON 86(T)=CCUG 49543(T)), was isolated from lung tissue of a cat.

Prevalence of methicillin-resistant Staphylococcus aureus among staff and pets in a small animal referral hospital in the UK

OBJECTIVES

The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and the possible relatedness between human and animal isolates were investigated among veterinary staff and hospitalized animals in a referral small animal hospital in the UK.

METHODS

A total of 300 swab samples were taken from nasal and oral mucosae of 78 veterinary staff, 45 dogs, 12 cats and from 30 environmental surfaces. Staphylococci were isolated by selective enrichment and characterized by biochemical tests and antimicrobial disc susceptibility testing. MRSA isolates were genotypically confirmed by PCR and typed by PFGE.

RESULTS

MRSA was isolated from 14 staff (17.9%), four dogs (9%), and three environmental sites (10%) yielding a total of 28 MRSA isolates. PFGE analysis revealed that most MRSA isolates were indistinguishable (56%) or closely related (26%) to EMRSA-15, one of the two epidemic MRSA strains dominant in UK hospitals. Like EMRSA-15, the predominant strain isolated from staff, dogs and environmental sites was resistant to fluoroquinolones in addition to all beta-lactams.

CONCLUSIONS

The study provides evidence of EMRSA-15 mucosal carriage in veterinary staff and hospitalized dogs, with the risk of MRSA carriage in veterinary staff being significantly higher than reported for the UK healthy community. EMRSA-15 was predominant in the hospital environment, including humans, dogs, and inanimate objects, but the mode by which the strain was introduced and spread remains uncertain.

Prevalence and Characterization of Staphylococcus aureus and Enterotoxigenic Staphylococcus aureus in Retail Raw Chicken Meat Throughout Japan

A total of 444 samples of raw chicken meat (thighs, breasts, wings, livers, gizzards, hearts and ovaries) that retailed at 145 different supermarkets in 47 prefectures in Japan were examined for contamination with Staphylococcus aureus in association with its enterotoxigenicity. S. aureus was isolated from 292 (65.8%) of the samples, and from 131 of the 145 supermarkets. There was no significant difference in the detection rate of S. aureus according to the type of meat examined. About 80% of 714 isolates belonged to the poultry (57.1%) and human biotypes (22.1%). Seventy-eight (21.7%) of 360 isolates were enterotoxigenic and isolated from 78 samples in 53 supermarkets in 31 prefectures. Staphylococcal enterotoxins (SEs) produced were SEB (50 isolates), SEA (14), SEC (8), SED (2), SEA+SEB (2), and SEA+SEC (2). Most of the enterotoxigenic isolates belonged to the human and poultry biotypes, coagulase type VII, VIII or IV, and were lysed by phages of group III. Identical SE types, biotypes, coagulase types and pulsed-field gel electrophoresis (PFGE) patterns were shown in isolates from different types of meat at the same supermarket and from samples taken from different supermarkets in the same prefectures or in isolates from samples obtained from several different prefectures. Among the 50 SEB-producing isolates, 27 yielded three similar PFGE patterns that differed by only a few fragments, suggesting that they were closely related genetically. The three patterns were found in isolates of samples that retailed at 17 supermarkets in 11 prefectures, indicating that they may be disseminated among raw chicken meat in Japan.

Rabbit staphylococcosis: difficult solutions for serious problems

Staphylococcus aureus infections are a major problem in rabbitries. The main manifestations are subcutaneous abscesses, mastitis, pododermatitis and septicaemia. Two patterns of infection can be distinguished. In the first type, clinical signs remain limited to a small number of rabbits in a flock. This type has little economic importance and is caused by low-virulence S. aureus strains. In the second type, the disease shows an epidemic spread. Consequences are poor production results, infertility and death. This leads to chronic problems and a subsequent decline in production. The latter type is caused by high-virulence strains. Biotyping, phage typing and RAPD typing contribute to the characterisation of high-virulence S. aureus strains. Administration of antibiotics, disinfection of the environment and vaccination are not able to solve the problems. Therefore, the only effective measure is to cull the entire flock and to restart with a new rabbit population after thorough disinfection. Limiting the introduction of new rabbits in existing rabbitries and reducing contacts between rabbitries to an absolute minimum are currently the only way to face this most difficult problem.

Identification and antimicrobial susceptibility of coagulase positive staphylococci isolated from healthy dogs and dogs suffering from otitis externa

A total of 67 strains of coagulase positive staphylococci isolated from healthy dogs and dogs suffering from otitis externa were studied. Twenty-two isolates were from healthy dogs (five from hound dogs and 17 from companion dogs) and 45 from dogs suffering otitis externa (14 from hound dogs and 31 from companion dogs). Presumptive identification was attempted using the following tests: production of acetoin, anaerobic utilization of mannitol, acid production from mannitol, presence of beta-galactosidase, and growth on P agar supplemented with different concentrations of acriflavine. Susceptibility of staphylococci to 16 antibiotics was determined. Most effective antibiotics were imipenem, amoxycillin/clavulanic acid, ciprofloxacin, tobramycin, gentamicin and marbofloxacin. Penicillin, ampicillin and polymyxin B showed the lowest activity. There were no significant differences in antimicrobial susceptibility among isolates from healthy dogs and dogs suffering from otitis externa.

Development of a PCR test for the identification of Staphylococcus intermedius based on the 16S rDNA sequence

The development of a PCR assay based on the 16S ribosomal RNA gene (rDNA) sequence was carried out for the identification of Staphylococcus intermedius. Sixty-six strains of S. intermedius, 70 of Staphylococcus aureus and 2 of Staphylococcus hyicus were examined for the assay. The 16S rDNA, of which the PCR target fragment makes up 901 bp corresponding to the sequence data of the gene, was detected in all strains of S. intermedius, but it was not detected in any strains of either S. aureus or S. hyicus. These results suggest that the PCR allows a simple and precise identification of S. intermedius.

Colonization of neonatal puppies by Staphylococcus intermedius

Cutaneous and mucosal carriage of Staphylococcus intermedius was determined in five Cavalier King Charles spaniel bitches, living in normal domestic environment, and their 18 puppies during the immediate prepartum period and after whelping, over a total of 8 weeks, using quantitative swab techniques. Within 8 h of birth S. intermedius was isolated from each puppy. The nose and mouth were the most frequently colonized mucosal sites (83 and 78%, respectively). At that time S. intermedius was isolated from the abdominal skin in 78% of the puppies. One day postpartum the mucosal populations increased significantly (P < 0.001) but fell 6 (P < 0.01) and 20 (P < 0.001) days later. Populations from abdominal skin reduced during the first and fourth weeks postpartum (P < 0.05 for both). This study indicates that in the domestic environment S. intermedius establishes itself soon after birth. The level of colonization by S. intermedius in the bitches seems to influence the colonization by pathogenic staphylococci in puppies.

Characterization of Staphylococcus intermedius from pigeons, dogs, foxes, mink, and horses by pulsed-field gel electrophoresis

Staphylococcus intermedius from pigeons, dogs, foxes, mink, and horses, was characterized by pulsed-field gel electrophoresis (PFGE) to evaluate the use of this typing method for discriminating among strains. SmaI cut the chromosomal DNA into 7-13 fragments ranging from approximately 48 kb to 655 kb, with most of the detectable fragments being smaller than 172 kb. S. intermedius from various animals had a high degree of restriction fragment length polymorphism. Pigeon strains have a similar genotype, despite the difference in their isolation area. Phage typing indicated that the dog, fox, and mink strains belong to the canine I or canine II type. The PFGE method further differentiated the mink strains from the dog and fox strains with regard to three fragments between 256 kb and 570 kb. As such, genomic DNA fingerprinting by PFGE appears to be an effective technique for discriminating S. intermedius strains from various animals. A combination of PFGE typing and phage typing would provide more detailed information than the single method for ecological investigations of S. intermedius.

Antimicrobial susceptibility of Staphylococcus intermedius isolated from healthy and diseased dogs

A total of 90 strains of Staphylococcus intermedius isolated from dogs were examined for antimicrobial susceptibility. There were no significant differences in the distribution patterns of MICs between strains from 1982 to 1985 and those from 1999, and between strains from healthy dogs and those from diseased dogs. All of the strains were susceptible to ABPC, DMPPC, CEX, TDM, ERFX, BFLX, and FF at concentrations of 0.05 to 6.25 microg/ml. The MICs of OTC, KM, EM, AIV-TS, and LCM were distributed in a broad range of 0.1 to >100 microg/ml, indicating the existence of resistant as well as susceptible populations of S. intermedius. Thirty-three strains (36.7%) were resistant to one or more anitmicrobial agents such as OTC (n=32), KM (n=9), EM (n=7), AIV-TS (n=7), and LCM (n=7).

Elimination of Staphylococcus intermedius in healthy dogs by topical treatment with fusidic acid

Cutaneous and mucosal carriage of Staphylococcus intermedius was investigated in six healthy beagles before and after application of fusidic acid to mucosal surfaces as 1 per cent viscous eye drops twice daily for seven days. Bacterial populations were determined repeatedly over four weeks using quantitative techniques. The overall cutaneous populations of S intermedius reduced significantly (P < 0.001) two days after treatment but returned to pretreatment levels after a further week. The mucosal frequency of S intermedius reduced significantly (P < 0.01) two days after treatment and remained reduced (P < 0.01) at the end of the study. The mucosal populations were also reduced (P < 0.01) two days after treatment and remained lower (P < 0.05) after a further week. No such changes occurred in the control group of six beagles. The study indicates the importance of mucosae as carriage sites for S intermedius in dogs. This form of therapy may be useful as an additional tool against canine recurrent pyoderma.

Antibiotic resistance genes in coagulase-negative staphylococci isolated from food

Coagulase-negative staphylococci were isolated from different raw milk cheeses and raw meat products and screened for their antibiotic resistances. They were identified as Staphylococcus xylosus, S. lentus, S. caprae, S. epidemidis and S. haemolyticus. The most frequent resistances found were those to chloramphenicol, tetracycline, erythromycin and lincomycin. They have been characterized on the molecular level. The chloramphenicol resistance genes were localized in several S. xylosus and S. caprae on plasmids with sizes ranging from 3.8-kb to 4.3-kb and were identified as chloramphenicol acetyltransferase (cat). All the tetracycline resistant strains were identified as S. xylosus and harboured a 4.4-kb plasmid carrying the tetracycline efflux resistance gene (tetK). The two erythromycin/lincomycin resistant S. caprae and S. epidermidis strains did not hybridize with the MLSB resistance genes ermAM, ermA, ermB and ermC. Three erythromycin resistant Staphylococcus sp. strains harboured an erythromycin efflux resistance gene (msr) localized twice on a 18-kb plasmid and once on the chromosome. A S. haemolyticus strain showing resistance to both lincomycin and clindamycin harboured a linA gene-carrying 2.2-kb plasmid. Further resistances to gentamicin, penicillin and kanamycin were less frequently observed and yet not characterized on a molecular level.

Importance of Staphylococcus hyicus ssp hyicus as a cause of arthritis in pigs up to 12 weeks of age

Lame pigs, up to 12 weeks of age, were necropsied to establish a diagnosis. Of 175 pigs examined, 165 were confirmed to have arthritis by histopathological examination of joint tissues. Lesions were most common in the elbow and tarsal joints and least common in the joints of the feet. Typically, there was severe fibrinopurulent inflammation of synovial membranes regardless of the bacteria isolated. A bacterial aetiology was found in 114 (69%) of the 165 pigs. In arthritic pigs in which an aetiology was established the causative agents were Staphylococcus hyicus ssp hyicus (24.6%), Streptococcus equisimilis (26.3%), Actinomyces pyogenes (13.2%), Staphylococcus aureus (7.9%) and Haemophilus parasuis (7.9%). While gender did not affect the prevalence of arthritis, there was an age influence, most of the pigs culled for arthritis being under 6 weeks of age.

In vitro activity of fifteen antimicrobial agents against methicillin-resistant and methicillin-susceptible Staphylococcus intermedius

In this study the susceptibility of 91 methicillin-resistant and -susceptible Staphylococcus intermedius strains (MRSI and MSSI, respectively) against 15 antimicrobial agents was determined. The activity of the antimicrobial agents was studied at pH 7.2 and pH 8.5. Methicillin was more active at pH 7.2 (28 strains methicillin-resistant) than at pH 8.5 (55 strains methicillin-resistant). Gentamicin showed excellent activity, with only 3 strains resistant at pH 8.5. However, gentamicin would have to be administered parenterally. Oxytetracycline cannot be recommended for treatment of canine staphylococcal dermatitis, due to the high percentage (over 25%) of strains that were found to be resistant. Clindamycin showed little activity in inhibiting growth of the strains studied, the percent resistance at pH 7.2 was 93.4%. Rifampin behaved differently at the two pH values. However, a close relationship was noted between methicillin-resistant and rifampin-resistant strains, particularly at the lower pH. Of the fluoroquinolones, ciprofloxacin or enrofloxacin would be a good useful alternative for the treatment of methicillin-resistant strains of S. intermedius. Lastly, very high resistance to sulphamethoxypyridazine was found, as was the case with trimethoprim and a combination of trimethoprim/sulphamethoxypyridazine, against not only MRSI but also MSSI strains.

Factors associated with elevated cutaneous Malassezia pachydermatis populations in dogs with pruritic skin disease

The prevalences of breeds and concurrent diseases in a group of 40 dogs with pruritic skin disease associated with elevated cutaneous Malassezia pachydermatis populations were compared with samples of a dermatological hospital population. The ages and genders of the affected dogs were comparable to those of the dermatology population. Basset hounds, cocker spaniels and West Highland white terriers were significantly overrepresented. Concurrent diseases were diagnosed in 27 dogs, of which 15 were atopic. However, the prevalences of atopic disease, primary keratinisation defects and endocrinopathies in dogs with elevated cutaneous M pachydermatis populations were comparable to those in the dermatology population as a whole. These results indicate that certain breeds are predisposed to the development of elevated cutaneous M pachydermatis populations and that concurrent skin diseases can frequently be identified in affected dogs. However, the relationship between these concurrent diseases and abnormal M pachydermatis populations remains unclear.

Clinical and microbiological observations of early polytetrafluoroethylene membrane exposure in guided bone regeneration. Case reports in primates

Premature membrane exposure at one week is described in 3 Macaca mulatta monkeys as part of a sequence of experiments on guided bone regeneration. Clinical sequelae include redness, edema, and tissue slough. Bacteroides fragilis, Streptococcus pneumoniae, Prevotella intermedia, and Staphylococcus intermedius were detected at all prematurely exposed sites. Pseudomonas maltophilia, Strept, pneumoniae, and P. intermedia were the predominant organisms detected and consisted of more than 10% of the total anaerobic count.

Comparative in vitro activity of 11 beta-lactam antibiotics against 91 Staphylococcus intermedius strains isolated from staphylococcal dermatitis in dogs

A study was made of the susceptibility of 91 strains of Staphylococcus intermedius, isolated from staphylococcal dermatitis of dogs, to 11 beta-lactam antimicrobial agents. The activity of these antimicrobial agents against all strains was tested at pH 7.2 and 8.5. Finally, a comparative study was made of the susceptibility of these micro-organisms, dividing them into six groups: beta-lactamase positive and negative, methicillin resistant and susceptible and oxacillin resistant and susceptible. Only three of the 11 antimicrobial agents studied exhibited satisfactory behaviour at the two pH levels studied: mezlocillin, cefazolin and cefalotine. There was a good correlation at pH 8.5 between methicillin-resistant strains and those resistant to penicillin G, ampicillin, amoxycillin, cefamandole and cefuroxime. This correlation was not observed, however, between oxacillin-resistant strains and strains resistant to the other antimicrobial agents studied.

Comparison of two shampoos for treatment of Malassezia pachydermatis-associated seborrhoeic dermatitis in basset hounds

A randomised-double-blind parallel study compared the clinical and antimicrobial efficacies of a miconazole-chlorhexidine shampoo with a selenium sulphide shampoo for the treatment of seborrhoeic dermatitis associated with Malassezia pachydermatis in 33 basset hounds. All 16 miconazole-chlorhexidine treated hounds and 11 of 17 selenium sulphide treated hounds improved when shampooed at three-day intervals for three weeks. The miconazole-chlorhexidine treated hounds showed significantly greater reductions in pruritus (P < 0.01), erythema (P < 0.001), exudation (P < 0.01) and overall severity (P < 0.001), and in counts of M pachydermatis (P < 0.001), total bacteria (P < 0.001) and coagulase-positive staphylococci (P < 0.001), when compared to the selenium sulphide treated group. Improvements in scaling and coat condition did not vary significantly between the two groups. These results indicate that seborrhoeic dermatitis in basset hounds is often associated with elevated cutaneous populations of M pachydermatis and bacteria, and that the miconazole-chlorhexidine shampoo is more effective than the selenium sulphide product for the treatment for this disease.

Numerical taxonomy of an 'atypical' population of gram-positive cocci isolated from freshly dressed lamb carcasses

One hundred Gram-positive, catalase-positive strains were isolated from freshly dressed lamb carcasses. They were randomly selected from a non-selective medium and tested for 75 characters. Only nine cultures could be identified by conventional methods. A numerical taxonomic study was conducted on the whole population and 25 reference strains. At the 80% similarity level (Ssm), ten clusters were formed. Five of them were entirely composed of reference strains. Phena V and VIII contained seven isolates and two reference strains of Micrococcus. Phena VI (six unidentified isolates), VII (nine staphylococci) and IX (69 unidentified isolates) were more related to M. kristinae than to the remaining reference strains. Properties with possible implications in meat spoilage were: strong lipolytic activity (76%), anaerobic growth (85%), tolerance to 15% (w/v) NaCl (95%) and ability to grow at 15 degrees C (95%) and 4 degrees C (26%).

Characterization of Staphylococcus spp. and Micrococcus spp. isolated from Iberian ham throughout the ripening process

The Iberian dry cured ham is an uncooked meat product highly appreciated because of its characteristic flavour. This product is obtained from highly marbled Iberian pig hindlegs after 18-24 months of maturation under natural environmental conditions. The role of Micrococcaceae in the development of the aroma characteristics of this products remains unclear. Identification of Gram-positive, catalase-positive cocci isolated from Mannitol Salt Agar plates showed that Staphylococcus xylosus followed by Staphylococcus equorum are the predominant organisms, even after 16 months of maturing. A remarkable variety of types of both staphylococci and micrococci are detected at any sampling time. The metabolic activities of these organisms could contribute to the characteristics of the final product.

Some factors inhibiting amplification of the Staphylococcus aureus enterotoxin C1 gene (sec+) by PCR

PCR amplification of the sec+ gene for staphylococcal enterotoxin C1 (SEC1) can be achieved from as little as 10 fg total genomic DNA (equivalent to less than 10 cells) using two nested primer pairs. The presence of bacterial cells, particularly thermonuclease-producing staphylococci, and the thermonuclease enzyme (TNase) itself, were found to be factors which individually and together reduced the sensitivity of PCR amplification.

Pathogenic staphylococci and staphylococcal infections in canaries

Staphylococcus aureus was isolated from six cases of bacterial infection in canaries, Staphylococcus hyicus from three and Staphylococcus intermedius from one case. Staphylococcus aureus was most often involved in outbreaks of septicaemia, with or without 'Megabacterium' proventriculitis. The other coccal species were mainly complicating disease caused by Atoxoplasma (Lankesterella), Chlamydia psittaci and canary pox.

Development of a phage typing system for Staphylococcus hyicus

Bacteriophages were released by 98% of 100 Staphylococcus hyicus strains studied after treatment with mitomycin C. Twenty-three phages with different lytic spectra were included in a phage typing system and used for typing S. hyicus. On a test-set of 100 epidemiologically unrelated S. hyicus strains isolated from Danish pig herds, the phages were able to type 92% of the strains, producing 16 different phage types. Reproducibility of the phage typing system after subculture of the strains and using fresh phage stock was 96%. Typability ranged from 52 to 80% when typing porcine strains originating from other countries. Although phages were isolated from porcine skin strains exclusively, the system produced phage types in S. hyicus strains of bovine origin. Ten strains of S. aureus and S. chromogens were not typable by these phages. Strains belonging to one phage type (A/B/C/W) were isolated significantly more often from piglets with exudative epidermidis than from healthy piglets. The phage typing system described appears to be a valuable tool in diagnosis of exudative epidermidis in pigs, and furthermore, might be of value in epidemiological studies of S. hyicus.

Diagnostic value of phage typing, antibiogram typing, and plasmid profiling of Staphylococcus hyicus from piglets with exudative epidermitis

A total of 989 isolates of S. hyicus were recovered from the skin of 103 piglets (9.6 isolates per piglet) with exudative epidermitis (EE), and phage typed. Phage patterns of 806 typable isolates (81%) could be divided into 44 distinct phage types. From 1 to 6 different phage types were found on individual piglets, with an average of 1.9 phage type per piglet. Antibiogram patterns of 384 isolates from 40 randomly selected piglets with EE showed a mean of 2.3 different antibiograms per investigated piglet, ranging from 1 to 6 antibiograms per piglet. Plasmid profiles of 248 S. hyicus isolates from 25 randomly selected piglets showed an average of 2.8 different plasmid profiles per piglet. Seven EE outbreaks in pig herds vaccinated with autogenous vaccine were investigated. In all these herds, strains recovered from the present outbreak differed by two or more type markers to the strains from the previous outbreak used for production of the autogenous vaccine. This finding suggest, that lack of protection might be due to the presence of other virulent types in the investigated herd than those used for production of autogenous vaccine.

A longitudinal study of Staphylococcus hyicus colonization of vagina of gilts and transmission to piglets

High Staphylococcus hyicus colonization rates were found in vaginal samples of healthy breeding sows and in skin samples of their offspring. Twenty-two different phage types were identified among the 720 isolates of S. hyicus examined. Two to 13 different phage types were isolated per herd. Phage typing, as well as characterization of about 10% of the isolates by plasmid profiles and antibiogram patterns, showed that, several different clones of S. hyicus could be present simultaneously in vagina of gilts and also on skin of piglets. Generally isolates from the vagina of one animal were identical as regards to phage types, plasmid profiles, and antibiogram patterns during the entire investigation period. Isolates from the skin of piglets were of the same type as their mothers, indicating that vertical transmission had taken place. S. hyicus strains isolated from the skin of piglets within 24 h after birth were identical to strains isolated 3 weeks after birth from the same litter, indicating that the vaginal strains became part of a stable skin flora.

A study of phenotypic variation of Staphylococcus epidermidis using Congo red agar

This study examines a series of phenotypic variants of Staphylococcus epidermidis that were generated from a pair of parent variants, isolated from valvular tissue of a patient with prosthetic valve endocarditis. The variants were initially classified by examining their colonial morphology on Congo red agar. In addition to differences in Congo red binding and colonial morphology, they differed in the expression of several surface components and enzymes. Despite these phenotypic differences, all variants had the same restriction endonuclease profile of plasmid DNA. Examination of a collection of clinical isolates demonstrated that phenotypic variation is a common property of S. epidermidis. The ability to express different combinations of surface components and enzymes could contribute to the virulence of S. epidermidis strains by enabling these organisms to colonize a range of diverse environments.

Colonization of neonatal puppies by staphylococci

The composition of the normal staphylococcal flora of bitches and their litters held in a breeding unit was studied. The animals were sampled at a number of sites using moistened swabs. Six bitches were sampled daily, for 10 days, before whelping and then, together with four puppies per litter, at whelping (day 11) and at 1 and 7 days thereafter. Staphylococcus intermedius formed the predominant staphylococcal isolate. S. intermedius counts at the oral and nasal sites on the bitches did not change markedly before whelping and remained low (< 6 cfu/swab). Significant rises in the oral counts on both the bitches (P < 0.05) and puppies (P < 0.001) were then observed after whelping (days 11-18). Abdominal counts on both the bitches and puppies also rose (P < 0.001) after whelping. S. intermedius counts at the vaginal vestibulum of the pregnant bitches were found to be higher than at any other site sampled and did not alter markedly until whelping when a decrease (P = 0.05; days 10-12) was observed. S. intermedius was not found at the anal site in any of the six bitches and only transiently colonized five of the puppies.

Detection of enterotoxins and TSST-1 secreted by Staphylococcus aureus isolated from ruminant mastitis. Comparison of ELISA and immunoblot

The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin-1 (TSST-1) was studied in 81 strains of Staphylococcus aureus isolated from cases of mastitis in cattle, goats and sheep. SE and TSST-1 were detected by two techniques: ELISA double antibody sandwich, and an immunoblot technique combined with a semiautomated electrophoresis system. More Staph. aureus strains isolated from sheep produced enterotoxins than those from goats and cattle. SEC was the predominant type in all isolates from these animal species. The highest proportion of strains producing TSST-1 were obtained from sheep, twice as many as those from goats or cows. The two techniques gave similar results, as all the strains positive by immunoblot were also positive by ELISA, and only three were positive by ELISA but negative by immunoblot.

Enterotoxigenicity of Staphylococcus strains isolated from Spanish dry-cured hams

The ability of 135 Staphylococcus strains isolated from Spanish dry-cured hams to produce enterotoxins in culture was investigated by the reversed passive latex agglutination method. A high percentage of enterotoxigenic Staphylococcus aureus strains (85.9%) was recorded, and 54.3% of these produced enterotoxin A. One of the two Staphylococcus epidermidis strains produced enterotoxin C. The reversed passive latex agglutination method yielded satisfactory results.

Occurrence of Staphylococcus intermedius on the hair and skin of normal dogs

Aerobic bacterial populations were studied on the distal hair coat and at the skin surface of the shoulder, rump and abdomen of 10 healthy dogs. Coagulase negative staphylococci (CNS) were more frequently isolated from the hair than the skin at the shoulder and rump. There was no difference in the isolation rate of coagulase positive staphylococci (CPS) (Staphylococcus intermedius) between the hair and skin. Total skin counts were greatest on the abdomen whereas CNS counts from the hair were least at this site. There were no differences between CPS counts at the three sites on either hair or skin. The populations on the relatively unfavourable microenvironment of the distal hair may represent contamination rather than colonisation. The low populations of CPS at the skin surface also indicate contamination or transient colonisation rather than true resident status.

Production of staphylococcal enterotoxins and TSST-1 by coagulase negative staphylococci isolated from ruminant mastitis

The production of staphylococcal enterotoxins (SE) and toxic shock syndrome toxin-1 by 40 coagulase negative staphylococci isolated from sheep, goat and cow mastitis was studied. Both ELISA double sandwich and Western blot were used to detect the production of these toxins. Only two strains of S. xylosus were enterotoxigenic, producing SEC. TSST-1 was seen to be produced by 5 strains of S. xylosus, 1 S. sciuri and 2 S. epidermidis. Results obtained by ELISA and by Western blot agreed in all cases except in one strain of S. epidermidis which was only positive using ELISA.

Enterotoxin and toxic shock syndrome toxin-one production by staphylococci isolated from mastitis in sheep

From 160 staphylococci isolated from ovine mastitis, 125 were identified as coagulase-positive staphylococci (CPS) and 35 as coagulase-negative staphylococci (CNS). Of these, 108 (87.8%) S. aureus produced at least one of the staphylococcal enterotoxins (SE) described. However, no CNS was found to be enterotoxigenic. Enterotoxin C (SEC) was the type most frequently produced. TSST-1 was shown to be produced by 91 (74.0%) of S. aureus, almost invariably in combination with SEC. Three CNS strains were also found to produce TSST-1 (two strains of S. xylosus and one strain of S. epidermidis).

Toxic shock syndrome toxin 1 (TSST-1) production by staphylococci isolated from goats and presence of specific antibodies to TSST-1 in serum and milk

The ability of staphylococcal strains isolated from different anatomical sites in 133 healthy goats to produce toxic shock syndrome toxin 1 (TSST-1) and the presence of antibodies to this toxin in serum and milk were studied. The enzyme-linked immunosorbent assay method was used to detect both the toxin and the presence of antibodies. Of a total of 342 staphylococcal strains studied, 86 (25.2%) were found to produce TSST-1. Specific antibodies to TSST-1 were found in the serum of 57 (42.9%) of the animals studied and the milk of 63 (47.4%) of the animals. These results suggest that goats are frequently in contact with staphylococci that produce TSST-1, a toxin usually associated with Staphylococcus aureus strains isolated from cases of toxic shock syndrome in humans.

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.

Detection of antibodies to staphylococcal enterotoxins in the serum and milk of healthy goats

A study was made of the presence of antibodies (Ab) to staphylococcal enterotoxins A to E (SEA-SEE) in the serum and milk of 133 healthy goats, using a competitive ELISA method. Antibodies to some enterotoxins were detected in 83 sera (62.4%) and in 41 (30.8%) milk samples. In serum, antibodies to all SE types were detected, the most frequent being antibodies to SEA (24.8%). Milk contained antibodies to SEA, SEB and SEC, the latter being the most frequent (24.8%). A statistical study was performed to correlate the number of animals harbouring antibodies to a given enterotoxin with the presence in these animals of staphylococci producing that enterotoxin.