Proteolytic zymograms of Staphylococcus hyicus subsp. hyicus isolated from pigs, chickens and cows

The extracellular proteases of Staphylococcus hyicus subsp. hyicus were assayed by a zymogram showing caseinolysis and gelatinolysis. Four bands were associated with caseinolysis or with gelatinolysis. The patterns shown by strains isolated from pigs, chickens and cows were compared; isolates from pigs differed from those isolated from chickens or cows but strains isolated from diseased and healthy pigs could not be differentiated.     

Bacteriophage typing of Staphylococcus hyicus subsp hyicus isolated from pigs

Four phages were isolated and used for typing Staphylococcus hyicus subsp hyicus isolated from pigs with or without exudative epidermatitis (EE) in Japan. Sixty-four (85.3%) of the 75 isolates examined were typeable at either routine test dilution (RTD) or 100 X RTD. Two or more kinds of phage patterns were present in the isolates from each pig with EE. All isolates from healthy pigs showed a single-phage pattern. Fourteen (32.6%) of 43 isolates and 7 (87.5%) of 8 isolates from pigs with EE in Belgium and Czechoslovakia, respectively, were typeable with the 4 phages. None of 180 isolates of S aureus, 7 (6.4%) of 110 isolates of S intermedius, and 2 (2.3%) of 86 isolates of S epidermidis were typeable.     

Lysogeny and other characteristics of Staphylococcus hyicus isolated from chickens

Lysogeny was readily demonstrated among strains of Staphylococcus hyicus that were isolated from chickens. Susceptibility to phage lysis was affected by prophage immunity, but lipase activity and erythromycin resistance were not affected by the presence of temperate phage. In contrast to previously published results, lipase-negative strains of S. hyicus were relatively common and the use of selective media based on lipase activity would have been unsuitable for detection of the S. hyicus strains examined.     

Plasmids and resistance to antimicrobial agents and heavy metals in Staphylococcus hyicus from pigs and cattle

Staphylococcus hyicus-cultures, isolated from piglets and cattle with skin lesions were investigated for their plasmid content and their resistance to antimicrobial agents and heavy metals. Several plasmids of different sizes could be detected in most of the 32 "porcine" S. hyicus-isolates, whereas none of the 20 "bovine" S. hyicus-cultures possessed any plasmid. The "porcine" S. hyicus-isolates were much more resistant to antimicrobial substances than the "bovine" S. hyicus-cultures. However, the "porcine" and "bovine" S. hyicus-cultures did not differ in their resistance to heavy metals.     

Antibiotic resistance of Escherichia coli strains isolated from chickens with colisepticaemia in Morocco

Sixty-two strains of Escherichia coli were isolated in 58 farms from broiler chickens showing respiratory signs and lesions characteristic of avian colibacillosis. Serological examination of these strains showed that the types 078, 01 and 02 (for the somatic antigen) and K1 (for the capsular antigen) were the most frequently found. Newcastle disease virus was also isolated in two cases. All the strains of E. coli isolated were sensitive to colistin, flumequine and gentamicin. A few strains were resistant to neomycin, nalidixic acid and trimethoprim. The frequency of strains resistant to nitrofurans, sulfonamides, chloramphenicol, spectinomycin and ampicillin was intermediate. Most strains were resistant to tetracycline. Multiple resistance was common.     

Isolation of exfoliative toxin from Staphylococcus hyicus subsp. hyicus and its exfoliative activity in the piglet

Exfoliative toxin was isolated from the sterile cell-free filtrate of 24 h culture of Staphylococcus hyicus subsp. hyicus strain P-1. The partial purification of exfoliative toxin produced by S. hyicus (shET) was performed by precipitation with 50-80% saturated ammonium sulfate, gel filtration on a Sephadex G-75 column and column chromatography on DEAE-cellulose. Partially purified shET (pp-shET) caused exfoliation in piglets at 8 to 12 h after intradermal or subcutaneous injection. However, heat-treated pp-shET did not cause exfoliation in piglets for up to 24 h after injection. On histopathological examination of the skin at 12 h after injection of pp-shET, an intraepidermal cleavage plane was shown between the stratum corneum and stratum granulosum and at the stratum granulosum.     

Zinc-resistance gene czrC identified in methicillin-resistant Staphylococcus hyicus isolated from pigs with exudative epidermitis

Methicillin-resistant Staphylococcus hyicus (MRSH) was investigated for czrC, a gene conferring zinc-resistance. The czrC gene was identified in 50% (14/28) of MRSH isolates, representing 14 pigs with exudative epidermitis from 8 farms. Newly weaned pigs, which are particularly susceptible to exudative epidermitis, are commonly fed high levels of zinc oxide.     

Assay of protein A in Staphylococcus hyicus subsp. hyicus by ELISA and immunoelectron microscopy

The presence and quantity of protein A in Staphylococcus hyicus subsp. hyicus isolates were examined by an enzyme-linked immunosorbent assay (ELISA) and immunoelectron microscopy. Cell-bound protein A was demonstrated in 45 (94%) of 48 isolates from diseased pigs and in 113 (86%) of 132 isolates from healthy pigs by ELISA using peroxidase-conjugated rabbit antibody, but was not found in isolates from chickens and cows. Most of these swine isolates contained about 100 to 300 ng of cell-bound protein A/ml. Extracellular protein A was not detected in any isolates from pigs, chickens or cows. In the immunoelectron microscopy assay, swine isolates were labeled with goat anti-mouse IgG conjugated to colloidal gold particles, but chicken and cow isolates were not labeled.     

Susceptibility of various animals and cultured cells to exfoliative toxin produced by Staphylococcus hyicus subsp. hyicus

In piglets inoculated with partially purified exfoliative toxin (pp-shET) produced by Staphylococcus hyicus subsp. hyicus, exfoliation was observed at 12 h after injection. Chickens inoculated with the same dose of pp-shET also showed exfoliation within 30 min of injection. However, exfoliation was not demonstrated in mouse, rat, guinea pig, hamster, dog or cat inoculated with pp-shET until 24 h after injection. In cultured cell lines, especially L-929 and Hep-2, the rounding effect occurred after incubation with pp-shET for 1 h. The rounding effect was also seen in five other cultured cells (NCTC 2544, HeLa/S3, HmLu-1, CHO and BHK-21) 6-24 h after exposure to pp-shET. These round cells survived for 72 h after inoculation and formed a monolayer 24 h after changeover to a toxin-free medium. The rounding effect was observed in cells after the formation of the monolayer, but not before. It was suggested that the rounding effect was not caused by the increase in cyclic AMP in cells inoculated with pp-shET but by the cleavage of intracellular contacts.     

兔源金黄色葡萄球菌的耐药性及耐药基因分析

为了解四川地区规模化兔场金黄色葡萄球菌(S.aureus)的耐药情况,本研究从四川地区部分规模化兔场共分离鉴定出41株S.aureus,采用纸片扩散法对分离株进行了耐药表型鉴定,同时采用PCR方法对相关耐药基因进行了检测。药敏试验结果显示:分离株对β-内酰胺类、氨基糖苷类、四环素类和大环内脂类药物的耐药率分别为87.80%、97.56%、78.05%和56.10%,对多肽类、喹诺酮类及磺胺类耐药率较低。耐药基因检测结果显示:所有分离株均检测到耐药基因,并且29株分离株具有多重耐药性,其中耐药基因mec A、tet、erm、aac(6')/aph(2')、ant(4',4')及aph(3')-III的检出率分别为75.61%、70.73%、46.34%、92.68%、80.49%及53.66%。结合耐药表型与耐药基因结果分析显示兔源S.aureus的耐药表型与耐药基因检出率基本呈正相关。本研究通过检测41株兔源S.aureus对临床常用抗生素的耐药性及相关耐药基因,初步掌握了四川地区规模化兔场S.aureus的耐药情况,为该地区规模化兔场预防及治疗葡萄球菌病临床合理用药提供了依据。     

泰国进口鳄鱼霍乱弧菌药敏试验

在某鳄鱼养殖场抽检的60份泰国进口鳄鱼肛拭子样品中,有12份检出霍乱弧菌。通过生化试验和血清学分型等鉴定,确认12株霍乱弧菌均为非O₁非O₁₃₉群霍乱弧菌。采用18种抗菌药物进行药敏试验,结果显示所有菌株对大多数抗菌药物高度敏感,对四环素等药物中度敏感,对氨苄青霉素和氧呱嗪青霉素不敏感。     

Incidence of quinolone resistance in strains of Salmonella isolated from poultry, cattle and pigs in Germany between 1998 and 2001

This paper reports the susceptibility to the quinolone nalidixic acid and the fluoroquinolone ciprofloxacin of 14,514 strains of Salmonella isolated in Germany from poultry, cattle and pigs between 1998 and 2001. Quinolone-resistant salmonellae were most frequently isolated from poultry, with a prevalence of 10.2 to 16.8 per cent. Poultry-associated serotypes, such as Salmonella Paratyphi B (d-tartrate positive), Salmonella Hadar and Salmonella Virchow, had the highest prevalence of quinolone resistance, ranging between 35 and 74 per cent. All the nalidixic acid-resistant strains also had a reduced susceptibility to ciprofloxacin, with minimum inhibitory concentrations (MICS) of 0.125 to 2 microg/ml. A comparison of the MICS for ciprofloxacin of the strains of these poultry-associated serotypes and Salmonella Enteritidis phage type 4 isolated in 1998/99 and 2000/01 indicated that there had been a shift towards higher MIC values of up to 2 microg/ml. The quinolone resistance-determining region (QRDR) of the gyrA gene and the homologue region of the parC gene of 31 selected strains were sequenced. Several different amino acid changes were observed in gyrA of the quinolone-resistant isolates at positions 83 and 87, but no substitutions were observed in parC.     

Trends in antimicrobial susceptibility in relation to antimicrobial usage and presence of resistance genes in Staphylococcus hyicus isolated from exudative epidermitis in pigs

From 1996 to 2001 a total of 467 Staphylococcus hyicus isolates from exudative epidermitis (EE) in pigs in Denmark were examined for susceptibility to 13 different antimicrobial agents. The presence of selected genes encoding macrolide (erm(A), erm(B) and erm(C)), penicillin (blaZ), streptogramin (vat, vga, vga(B), vat(B), vat(D) and vat(E)), streptomycin (aadE) and tetracycline resistance (tet(K), tet(L), tet(M) and tet(O)) were determined in selected isolates.The occurrence of erythromycin resistance increased from 33% in 1996 to a maximum of 62% in 1997 and decreased to 26% in 2001. Resistance to sulphametazole increased from 17% in 1996 to 30% in 1998 but has since decreased to 4% in 2001. Resistance to trimethoprim increased to 51% in 1997 and decreased to 21% in 2001. Resistance to tetracycline (21-31%) remained relatively constant during 1996-2000, but increased to 47% in 2001. Resistance to penicillin (54-75%) streptomycin (33-53%) and tetracycline (21-47%) remained relatively constant over the time investigated.All 48 penicillin resistant isolates examined contained the blaZ gene and 40 (85%) of the streptomycin resistant isolates the aadE gene. It was not possible to detect any streptogramin resistance gene in four streptogramin resistant isolates. Of the 55 erythromycin resistant isolates examined, five contained erm(A), 13 erm(B), 35 erm(C) and two both erm(A) and erm(C). The presence of erm(B) was confirmed by hybridization to plasmid profiles in all 13 PCR-positive isolates. Of 52 tetracycline resistant isolates examined, two contained tet(L), 38 tet(K) and 12 both tet(K) and tet(L).