SCC <Emphasis Type="Italic">mec</Emphasis> typing and antimicrobial resistance of methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> (MRSA) from pigs of Northeast India

Staphylococcus aureus is one of the most important pathogens of both humans and animal. Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that causes serious infections both in hospitals and communities due to its multidrug resistance tendency. This study was undertaken to characterize the MRSA isolates from pigs and to determine the antimicrobial resistance of these isolates. Forty nine MRSA strains (one strain per positive pig) isolated from pigs of Northeast India were characterized by SCCmec typing and antimicrobial resistance. The overall prevalence of MRSA was 7.02 % with the highest prevalence recorded in pigs aged 1–3 months (P = 0.001) and in nasal samples (P = 0.005). Two SCC mec types (type III and V) were found in Indian pigs with predominance of type V. All isolates were resistant to penicillin. Seventeen resistance groups were observed where 87.75 % isolates showed multidrug resistance (showed resistance to three or more classes of antimicrobials). The most predominant resistance pattern observed was Oxytetracycline + Penicillin + Sulfadiazine + Tetracycline accounting 12.24 % of the isolates. The present study contributes to the understanding of characteristics and antimicrobial resistance of porcine MRSA isolates which in turn will help in devising strategy for the control of this pathogen. Findings of the study also throw light on multidrug resistance MRSA and emphasize the need for judicious use of antimicrobials in animal practice.     

The analysis of <Emphasis Type="Italic">groEL</Emphasis> gene in <Emphasis Type="Italic">Salmonella enterica</Emphasis> subspecies <Emphasis Type="Italic">enterica</Emphasis> serovar Typhimurium isolated from avians by PCR-Restriction Fragment Length Polymorphism method

Salmonella enterica subspecies enterica serovar Typhimurium causes food-borne outbreaks and systemic diseases in humans and animals. groEL gene (also known as mopA gene in S. Typhimurium), possessing conserved sequence, plays an important role in invasion of bacteria. The purpose of present study was to identify the polymorphism of groEL gene among different avians in different regions by PCR-RFLP method. Fifty two S. Typhimurium isolates (Broiler (n = 13), Layer (n = 12), Duck (n = 5), Goose (n = 5), Sparrow (n = 8), Canary (n = 3), Pigeon (n = 5) and Casco parrot (n = 1). were identified using serotyping as well as multiplex-PCR. Then, amplification of groEL gene performed and amplified products subjected to restriction digestion with BsuRI enzyme. Three RFLP profiles, A, B and C, generated DNA fragments between approximately 100–1,000 bp in size, were observed. The RFLP profile A was observed in 35 (67.3%), profile B in 14 (26.9%) and profile C in 3 (5.77%) of isolates. S. Typhimurium isolates recovered from 13 broilers (two of which profile A, 9 profile B and 2 profile C) and from 8 sparrows (two of which profile A, 5 profile B and 1 profile C) showed all three profiles, but 12 layers and other avians (including Canary (n = 3), Goose (n = 5), Duck (n = 5), Pigeon (n = 5) and Casco parrot (n = 1)) showed profile A. None of these profiles was allotted for a special region. The result of present study showed that S. Typhimurium undergoes genetic mutations in groEL gene under unpleasant milieu in different regions and in different avians. Thus, genetic diversity, despite conserved nature of groEL gene in S. Typhimurium, may exist but it depends on the condition where bacteria have settled. To our knowledge, three RFLP profiles of groEL gene generated by BsuRI restriction enzyme were not reported previously.     

Characteristics and virulence genes of <Emphasis Type="Italic">Escherichia coli</Emphasis> isolated from septicemic calves in southeast of Iran

Virulence factors are associated with the capacity of E. coli strains to cause intestinal and extraintestinal infections. Thirty one E. coli isolates were obtained from heart blood or internal organs of septicemic calves. The O serogroups of isolates were determined. PCR assays were performed to determine the phylogenetic groups and presence of specific virulence genes. Fourteen (45.16%) isolates belonged to seven O serogroups (O8, O15, O20, O45, O78, O101 and O103) and 17 (54.83%) isolates were O-nontypeable. E. coli isolates fall into three phylogenetic groups included 15 isolates belonged to B1, 9 to A and 7 to D phylogenetic groups. Nineteen (61.29%) isolates exhibited at least one of the virulence genes. F17 family (5 isolates f17b, 3 isolates f17c, 1 isolate f17a) genes and aerobactin encoding gene of iucD (5 isolates) were the two most prevalent virulence genes. Three isolates were positive for cnf2 and cdtIII genes in combination and they were O-nontypeable. AfaE-VIII, CS31A gene (clpG) and hemolysin encoding gene (hly) were detected in 3, 4 and 3 isolates respectively. None of the isolates contained the ipaH sequences and the genes encoding fimbria (F5, F41, S, P), AfaI adesin, toxins (LT-I, ST-I, SLT-I, SLT-II, CNF1 and CDT-IV) and intimin.     

Ovicidal activity of seven <Emphasis Type="Italic">Pochonia chlamydosporia</Emphasis> fungal isolates on <Emphasis Type="Italic">Ascaris suum</Emphasis> eggs

The ovicidal effect of the nematophagous fungus Pochonia chlamydosporia on eggs of Ascaris suum was tested under laboratory conditions. A. suum eggs were plated on 2% water–agar with seven fungal isolates (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) and control without fungus. After 5, 7, 10, 14, 15 and 21 days of incubation, approximately 100 eggs were removed from the plates and classified according to the following parameters: type 1, biochemical and physiological effect without morphological damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect with morphological alteration of eggshell and embryo showing hyphal penetration and internal egg colonization. The isolates effectively destroyed A. suum eggs and all types of effects were observed during the experiment. There was no variation in ovicidal capacity (type 3 effect) among the isolates (p > 0.05) throughout the experiment. After 21 days, isolate 5 showed the highest percentages of type 3 effect (58.33%). The results indicated that P. chlamydosporia (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) can destroy A. suum eggs and is, therefore, a potential biological control agent of nematodes.     

Alterations in coagulation parameters in dairy cows affected with acute mastitis caused by <Emphasis Type="Italic">E. coli</Emphasis> and <Emphasis Type="Italic">S. aureus</Emphasis> pathogens

This study was conducted to evaluate alterations in coagulation parameters in dairy cows affected with acute Escherichia coli (E. coli) mastitis and to compare those values to cows affected with Staphylococcus aureus (S. aureus ) mastitis. Twenty-four, adult Holstein-Friesian dairy cows affected with acute E. coli mastitis and 17 cows affected with S. aureus mastitis were studied. Cows affected with E. coli mastitis had significantly prolonged activated partial thromboplastin time (APTT) (P < 0.01), prothrombin time (PT) (P < 0.05) and decreased (P < 0.05) platelets numbers. Cows with S. aureus mastitis had only significantly prolonged APTT (P < 0.05) and decreased (P < 0.05) platelet counts. In the hematology evaluation, cows affected with E. coli and those affected with S. aureus mastitis had elevated hematocrit values but only significantly (P < 0.05) so in mastitic cows caused by E. coli. Both groups of mastitic cows had significantly (P < 0.05) lower leukocyte counts. Only cows with E. coli mastitis had significantly (P < 0.05) lower neutrophil count. In the plasma biochemical evaluation, creatinine concentrations were significantly (P < 0.05) elevated in both groups of cows. Blood urea nitrogen (BUN) concentration was only significantly elevated in cows affected with E. coli mastitis. Results of this study indicated that dairy cows affected with acute E. coli mastitis are more likely to develop clinical manifestations of disseminated intravascular coagulation than cows affected with S. aureus mastitis.     

Prevalence,species distribution and antimicrobial resistance patterns of methicillin-resistant staphylococci in Lithuanian pet animals

Background

The bacterial genus Staphylococcus consists of many species that causes infections in pet animals. Antimicrobial resistant staphylococci cause infections that are difficult to treat and they are important from the point of one health perspective. The aim of this study was to determine the prevalence of methicillin-resistant Staphylococcus (MRS) species, including methicillin-resistant S. aureus (MRSA) in diseased pet animals (Group A) and kennel dogs (Group B) in Lithuania and to characterize the isolates according to their antimicrobial resistance.

Results

Twenty-one MRS isolates were obtained from 395 clinical samples (5.3 %; CI 95 % 3.5-8.0) of Group A animals. Sixteen, four and one isolates were from dogs, cats and a pet rabbit, respectively. The mecA gene was present in 20 isolates, whereas one isolate was positive for the mecC gene. Twenty-one MRS isolates (20.0 %; CI 95 % 13.5-28.6) were obtained from the vagina of female dogs (n = 105) (Group B). All isolates carried the mecA gene. Twelve MRS species were isolated of which S. pseudintermedius was the most common (18/42) followed by S. haemolyticus (8/42) and S. lentus (4/42). MRSA was not found. All MRS strains were susceptible to vancomycin, linezolid, daptomycin and quinupristin/dalfopristin. Resistance to tetracycline (16/21), clindamycin (15/21) and erythromycin (14/21) was the most common types of resistance in Group A animals. Three isolates also demonstrated resistance to rifampin. Resistance toward gentamicin (16/21), ciprofloxacin (15/21), macrolides (15/21) and tetracycline (12/21) was the most common in kennel dogs (Group B). The most common genes encoding resistance to antimicrobials (excluding beta-lactams) in isolates from Group A pets were tetK (21/42), aph(3′)-IIIa (11/42) and aac(6'')-Ie-aph(2'''')-Ia (9/42).

Conclusions

A wide range of MRS species were found in pet animals in Lithuania. MRSA was not found.     

Antibiotic resistance and molecular characteristics of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> isolated from backyard-raised pigs and pig workers

Staphylococcus aureus is a commensal and pathogenic bacterium with impact on public health and livestock industry. The study investigated nasal carriage, antibiotic resistance, and molecular characterization of S. aureus in pigs and pig workers. Nasal swabs from 300 backyard-raised pigs and 101 pig workers were used for the study. Resulting isolates were confirmed using MALDI-TOF MS, tested for antibiotic resistance, and three different multiplex PCRs were used to detect enterotoxin, mecA, spaA, scn, and pvl genes. spa typing was used to annotate the isolates into MLST clonal complexes (CC). Structured questionnaire was used to access possible risk factors for S. aureus carriage. The prevalence of S. aureus in pigs and pig workers were 5.3 and 12.9%, respectively. The isolates were resistant to beta-lactams (97%), tetracycline (62%), sulfonamide (52%), aminoglycoside (20.6%), fluoroquinolone (24%), and mupirocin (3.4%). Twenty seven (93%) of the isolates carried scn, 7(24%) pvl, and 12 (41%) enterotoxin genes, respectively. Questionnaire survey showed medical-related occupation of household members was associated (p?<?0.5) with S. aureus carriage. This study suggests the presence of human multidrug resistant strains of S. aureus, high carriage of pvl, and enterotoxin genes, and CC5, CC15, and CC152 were the CC-groups shared among pigs and pig workers.     

Detection of intercellular adhesion genes and biofilm production in <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> isolated from bovine subclinical mastitis

Biofilm production by Staphylococcus aureus, an important virulence factor was investigated employing phenotypic and genotypic methods. A total of 102 S. aureus isolates from bovine subclinical mastitis cases were included in the study. Maximum number of biofilm producing strains were detected by Congo red agar (CRA) method (48.03%) followed by tube method (36.27%). Tissue culture plate method (TCP) without and with destaining identified 19.60 and 29.41% of S. aureus as biofilm producers, respectively. A polymerase chain reaction for detection of intercellular adhesion genes, icaA and icaD, responsible for biofilm formation was standardized. Of the 102 S. aureus isolates investigated, 36 (35.29%) strains revealed presence of both the genes. Considering polymerase chain reaction as a standard test, CRA and TCP without destaining were the most sensitive and specific, respectively. PCR technique standardized for detection of the icaA and icaD genes is reliable for identifying biofilm producing potential of S. aureus which may help in rapid detection of biofilm-producer Staphylococci. This would allow the early application of control measures.     

Re-emergence of multi-drug resistant <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Stanley from cattle

During 2009, Salmonella enterica subspecies enterica serovar Stanley isolates were recovered from cattle diagnostic specimens in southern Japan, and the isolates were examined to characterize the genetic determinants involved in this new pathogenicity that associated with mortality in cattle. All the isolates were multi-drug resistance exhibited resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, oxytetracycline, and kanamycin (ACSSuT-Km) encoded by bla _TEM, catA, aadA1, sul1, tet(A), and aphA1 genes, respectively. Class 1 integrons of 1.5-kb size were detected in all MDR isolates. The isolates harboured easily transferable plasmids of ca. 210-kb with the potential of transmitting resistance phenotype and genotype detected in the donor isolates. XbaI-digested PFGE patterns generated two related clusters implicated in the dissemination of multi-drug resistance amongst Salmonella Stanley isolates. An emergence of multi-drug resistant Salmonella Stanley amongst food-producing animals, including cattle is a threat to human health, as resistant isolates may be transmitted to humans through the food chain.     

In vitro predatory activity of nematophagous fungi <Emphasis Type="Italic">Duddingtonia flagrans</Emphasis> on infective larvae of <Emphasis Type="Italic">Oesophagostomum</Emphasis> spp. after passing through gastrointestinal tract of pigs

One isolate of predator fungi Duddingtonia flagrans (AC001) was assessed in vitro regarding the capacity of supporting the passage through pigs' gastrointestinal tract without loss of the ability of preying infective larvae Oesophagostomum spp. Fungal isolates survived the passage and were efficient in preying L₃ since the first 8 h of collection (p < 0.01) in relation to the control group (without fungus). Compared with control, there was a significant decrease (p < 0.01) of 59.6% (8 h), 71.7% (12 h), 76.8% (24 h), 81.0% (36 h), 78.0% (48 h), 76.1% (72 h), and 82.7% (96 h) in means of infective larvae Oesophagostomum spp. recovered from treatments with isolate AC001. Linear regression coefficients of L₃ of recovered Oesophagostomum spp. regarding the collections due to time were −0.621 for control, −1.40 for AC001, and −2.64 for NF34. Fungi D. flagrans (AC001) had demonstrated to be promising for use in the biological control of pig parasite Oesophagostomum spp.     

Antimicrobial resistance in Gram-positive bacteria from Timorese River Buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) skin microbiota

The Timorese River Buffalo (Bubalus bubalis) plays a major role in the East Timor economy, as it is an important source of animal protein in human nutrition. They are widely spread throughout the country and are in direct contact with the populations. In spite of this proximity, information on their microbiota is scarce. This work aimed at characterizing the skin microbiota of the East Timorese River Buffalo and its antimicrobial resistance profile. Skin swab samples were taken from 46 animals in surveys conducted in three farms located in “Suco de Nairete”, Lospalos district, during July and August 2006. Bacteria were isolated and identified according to conventional microbiological procedures. A total of 456 isolates were obtained, including Gram-positive (n = 243) and Gram-negative (n = 213) bacteria. Due to their importance as potential pathogens and as vehicles for antimicrobial resistance transmission, Gram-positive cocci (n = 27) and bacilli (n = 77) isolates were further characterized, and their antimicrobial resistance profile determined by the disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. This study shows the high bacterial diversity of B. bubalis skin microbiota, representing an important first step towards understanding its importance and epidemiologic role in animal health. It also points out the potential role of these animals as vectors of antimicrobial resistant bacteria dissemination and the importance of antimicrobial resistance monitoring in developing countries.     

Biological control of <Emphasis Type="Italic">Ascaris suum</Emphasis> eggs by <Emphasis Type="Italic">Pochonia chlamydosporia</Emphasis> fungus

Ascaris suum is a gastrointestinal nematode parasite of swines. The aim of this study was to observe Pochonia chlamydosporia fungus on biological control of A. suum eggs after fungus passage through swines gastrointestinal tract. Eighteen pigs, previously dewormed, were randomly divided into three groups: group 1, treated with the fungus isolate VC4; group 2, treated with the fungus isolate VC1 and group 3 did not receive fungus (control). In the treated groups, each animal received a 9 g single dose of mycelium mass containing P. chlamydosporia (VC1 or VC4). Thereafter, animal fecal samples were collected at the following intervals: 8, 12, 24, 36, 48, 72 and 96 h after treatment beginning and these were poured in Petri dishes containing 2% water-agar culture medium. Then, 1,000 A. suum eggs were poured into each dish and kept in an incubator at 26°C and in the dark for 30 days. After this period, approximately 100 eggs were removed from each Petri dish and morphologically analyzed under light microscopy following the ovicidal activity parameters. The higher percentage observed for isolated VC4 eggs destruction was 57.5% (36 h) after fungus administration and for isolate VC1 this percentage was 45.8% (24 h and 72 h) (p > 0.01). P. chlamydosporia remained viable after passing through the gastrointestinal tract of swines, maintaining its ability of destroying A. suum eggs.     

<Emphasis Type="Italic">Theileria</Emphasis> (<Emphasis Type="Italic">Babesia</Emphasis>) <Emphasis Type="Italic">equi</Emphasis> and <Emphasis Type="Italic">Babesia caballi</Emphasis> Infections in Horses in Galicia,Spain

The control of equine piroplasmosis is becoming increasingly important to maintain the international market open to the horse industry. The purpose of this study was to demonstrate the occurrence of equine piroplasmosis (Theileria equi and Babesia caballi) in Galicia, north-west Spain, and to compare haematological and serum biochemistry parameters between non-parasitaemic horses and horses parasitaemic with T. equi and B. caballi. Sixty serum samples (control group) were taken from healthy horses pastured on two farms, and examined for evidence of equine T. equi and B. caballi infection by indirect fluorescent antibody test (IFAT). Of the 60 samples, 24 (40%) and 17 (28.3%) samples were positive for T. equi and B. caballi, respectively. Twelve (20%) samples were positive for both parasites. Haematology and serum biochemistry were compared between controls and a series of 36 horses clinically affected by T. equi (25) or B. caballi (11). Compared with the healthy group, there was a 43% and 37% decrease in the haematocrit for T. equi and B. caballi infection, respectively. Parasitaemic horses presented an intense anaemia and serum biochemistry signs of liver damage. The anaemia was more severe in T. equi-infected than in B. caballi-infected horses. Our results suggest that equine piroplasmosis is widespread in the region and is a cause for concern.     

Methicillin‐Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types

The aim of this study was to investigate the phenotypic and genotypic diversity and anti‐microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north‐eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti‐microbial susceptibility by Kirby–Bauer disc diffusion method. Confirmation of methicillin‐resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP‐2a latex agglutination. Clonal relatedness of isolates was determined by pulsed‐field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase‐negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622‐ST1625). The findings show that MRSA is prevalent in milk from semi‐extensive dairy cows in north‐eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm‐to‐table continuum is warranted.     

Investigation of seroprevalence of <Emphasis Type="Italic">Theileria equi</Emphasis> and <Emphasis Type="Italic">Babesia caballi</Emphasis> in horses in Nigde province,Turkey

The prevalence of equine piroplasmosis caused by Theileria equi and Babesia caballi in Nigde, in central Anatolia, Turkey has remained unknown. Serum samples were obtained from a total of 125 horses and were tested for antibodies to T. equi and B. caballi using the Indirect Fluorescence Antibody Test (IFAT). Twenty-three (18.4%) horses were seropositive for equine piroplasmosis. Anti-T. equi was observed in 16 horses (12.8%) while anti-B. caballi was detected in 12 horses (9.6%). In addition, 5 serum samples were positive for both parasites. The prevalence rates of antibodies to T. equi and B. caballi for female and male horses were statistically indifferent (p = 0.19 and 0.90). The difference between the seropositivity rates to T. equi among age groups was statistically insignificant (p = 0.44) while the difference to B. caballi among age groups is statistically significant (p = 0.01). Seropositivity rates ranged from 2.9% to 25.7% for T. equi and 2.9% to 14.3% for B. caballi from the selected districts in Nigde. A statistically significant difference on seropositivity rates for the study sites was observed for only T.equi (p = 0.03). This study indicates that T. equi is higher than B. caballi in Nigde. This study was supported by the Scientific Research Projects Unit of Nigde University (FEB 2007/08).     

<Emphasis Type="Italic">Mycobacterium bovis</Emphasis>, but also <Emphasis Type="Italic">M. africanum</Emphasis> present in raw milk of pastoral cattle in north-central Nigeria

Using deletion typing technique, five mycobacteria isolated from unpasteurised milk samples from cows in north-central Nigeria were characterized as Mycobacterium bovis (n = 4) and M. africanum (n = 1). This report emphasizes that transmission between the animal and human reservoir is a serious threat in Nigeria.     

Serological and molecular detection of <Emphasis Type="Italic">Mycobacterium avium</Emphasis> subsp. <Emphasis Type="Italic">paratuberculosis</Emphasis> in cattle of dairy herds in Colombia

The objective of this study is the detection of Mycobacterium avium subsp. paratuberculosis (MAP) by serum enzyme-linked immunosorbent assay (ELISA), fecal polymerase chain reaction (PCR), and fecal culture in Colombian dairy herds. Serum and fecal samples from asymptomatic cows (n = 307) of 14 dairy herds were tested for MAP by an unabsorbed ELISA test (ELISA-A). Serum and fecal samples from positive ELISA-A animals (n = 31) were further tested by an absorbed ELISA test (ELISA-B) and PCR. Fecal samples from animals of herds positive by ELISA-A and PCR (n = 105) were inoculated onto three different culture media. ELISA-A produced positive results in 10% of the serum samples and 71% of the herds. ELISA-B and PCR results were positive in two and six serum and fecal samples from positive ELISA-A animals, respectively. Fecal samples were negative for MAP on all culture media. The results of this study confirmed the presence of MAP in local dairy herds and the difficulties of MAP detection in asymptomatic animals by ELISA, PCR, and fecal culture.     

Prevalence,molecular fingerprinting and drug resistance profile of enterovirulent <Emphasis Type="Italic">Escherichia coli</Emphasis> isolates from free-ranging yaks of Tawang district,Arunachal Pradesh,India

Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid, nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant for repeated occurrence of diarrhea in yaks.     

Polymorphism of <Emphasis Type="Italic">GDF</Emphasis>9 gene and its association with litter size in goats

Growth differentiation factor 9 (GDF9) was studied as a candidate gene for high prolificacy in goats. The polymorphism of exon 1 and flanking of GDF9 gene was detected by PCR-SSCP in five goat breeds with different prolificacy. Three genotypes (AA, AB and BB) were detected in goat breeds joined and two silent mutations (c.183A>C and c.336C>T) were identified in comparison genotype AA with genotype BB. Heterozygous genotype AB and wild type BB were detected in all five goat breeds and homozygous genotype AA was only detected in Jining Grey goats. The frequencies of genotypes AA, AB and BB were 0.18, 0.42 and 0.40 in Jining Grey goats, respectively. The genotype distribution was different (P < 0.01) between high prolificacy breed (Jining Grey goat) and low prolificacy breeds (Boer, Wendeng Dairy, Liaoning Cashmere and Beijing native goats). The Jining Grey goat does with genotype AA and AB had 0.72 (P < 0.01) and 0.56 (P < 0.01) kids more than those with genotype BB, respectively. The does with genotype AA had 0.16 (P > 0.05) kids more than those with genotype AB. These indicated that the allele A may have certain correlation with prolificacy in Jining Grey goats.