Dung treated by high-temperature composting is an optimal bedding material for suckling calves according to analyses of microbial composition, growth performance, health status, and behavior

Bedding materials are important for suckling buffalo calves. Treated dung has been used as a bedding material for dairy cows but the lack of an appropriate safety assessment limits its application. In this study, we evaluated the feasibility of treated dung (TD) as a bedding material for suckling calves by comparing TD with rice husk (RH) and rice straw (RS) bedding materials. The TD was prepared through high-temperature composting by Bacillus subtilis. Thirty-three newborn suckling buffalo calves (Bubalus bubalis, 40.06 ± 5.79 kg) were randomly divided into 3 bedding material groups (TD, RH, and RS) and bedded with 1 of the 3 bedding materials for 60 d. We compared cost, moisture content, bacterial counts, and microbial composition of the 3 bedding materials, and investigated growth performance, health status, behavior, rumen fermentation, and blood parameters of bedded calves. The results showed that TD contained the fewest gram-negative bacteria and coliforms on d 1 and 30 and the lowest relative abundance of Staphylococcus throughout the experiment. The RH and TD bedding materials had the lowest cost. Calves in the TD and RS groups showed a higher dry matter intake, and final body weight and average daily gain in the TD and RS groups tended to be higher than in the RH group. Calves in the TD and RS groups had a lower disease incidence (diarrhea and fever), fewer antibiotic treatments, and lower fecal score than calves in the RH group. Higher contents of IgG, IgA, and IgM were observed in calves of the TD and RS groups than in calves of the RH group on d 10, indicating higher immune ability in TD and RS groups. Furthermore, TD bedding increased the butyric acid content in the calf's rumen, whereas RS bedding increased the acetate content, which might be attributed to the longer time and higher frequency of eating bedding material in the RS group. Considering all of the above indicators, we concluded that TD is the optimal bedding material for calves based on economics, bacterial count, microbial diversity, growth performance, and health status. Our findings provide a valuable reference for bedding material choice and calf farming.

Effect of capsaicin supplementation on lactational and reproductive performance of Holstein cows during summer

Context Summer ambient temperature and humidity are major factors negatively influencing the physiology and the productive and reproductive efficiency of dairy cows. Various management and breeding approaches may be useful for maintaining productivity in dairy cows during summer to minimise these effects. Aims The experiment was designed to test a natural phytochemical supplementation of capsaicin (CPS), followed by a specific oestrus synchronisation protocol as a means to maintain productivity and reproductive performance of Chinese Holstein cows during summer in Hubei province, China. Methods Lactating Chinese Holstein cows (n = 109) were randomly divided into four groups and supplemented with 0 (control, n = 27), 20 (CPS-20, n = 26), 40 (CPS-40, n = 28) and 60 (CPS-60, n = 28) mg of capsaicin (CPS) per kg of total mixed ration respectively for continuous 30 days initiated on 10 July 2018. Milk production and composition were measured over 45 days from the start of CPS supplementation. After CPS supplementation, all cows were synchronised through a modified Ovsynch oestrus synchronisation protocol, and reproductive variables were recorded. Metabolic parameters were measured on the days before CPS supplementation, artificial insemination (AI) and 50 days post-AI. Key results Highest (P < 0.05) milk production were found in the CPS-40 group, and highest total solids and milk fat in the CPS-20 and CPS-40 groups. Milk urea nitrogen and milk fat were generally increased in CPS supplemented cows compared with the control group. Significant increases (P < 0.05) in oestrus response, ovulatory follicle size, ovulation rate and pregnancy rates were observed in the CPS-40 group compared with other groups. Glucose, lipoprotein esterase and aspartate aminotransferase were increased (P < 0.05) in CPS-40 and CPS-60 supplemented groups at the time of AI and 50 days post-AI. Conclusions CPS supplementation has the capacity to maintain milk yield, milk composition and serum metabolites in Chinese Holstein dairy cows during summer. The synergistic effect of CPS and the modified oestrus synchronisation protocol also improved reproductive variables of the cows. Implications Adoption of CPS as a supplement along with oestrus synchronisation could be a useful and economical strategy for dairy herd keepers to improve herd performance during summer.

Genome-wide association studies to identify quantitative trait loci affecting milk production traits in water buffalo

Water buffalo is the second largest resource of milk supply around the world, and it is well known for its distinctive milk quality in terms of fat, protein, lactose, vitamin, and mineral contents. Understanding the genetic architecture of milk production traits is important for future improvement by the buffalo breeding industry. The advance of genome-wide association studies (GWAS) provides an opportunity to identify potential genetic variants affecting important economical traits. In the present study, GWAS was performed for 489 buffaloes with 1,424 lactation records using the 90K Affymetrix Buffalo SNP Array (Affymetrix/Thermo Fisher Scientific, Santa Clara, CA). Collectively, 4 candidate single nucleotide polymorphisms (SNP) in 2 genomic regions were found to associate with buffalo milk production traits. One region affecting milk fat and protein percentage was located on the equivalent of Bos taurus autosome (BTA)3, spanning 43.3 to 43.8 Mb, which harbored the most likely candidate genes MFSD14A, SLC35A3, and PALMD. The other region on the equivalent of BTA14 at 66.5 to 67.0 Mb contained candidate genes RGS22 and VPS13B and influenced buffalo total milk yield, fat yield, and protein yield. Interestingly, both of the regions were reported to have quantitative trait loci affecting milk performance in dairy cattle. Furthermore, we suggest that buffaloes with the C allele at AX-85148558 and AX-85073877 loci and the G allele at AX-85106096 locus can be selected to improve milk fat yield in this buffalo-breeding program. Meanwhile, the G allele at AX-85063131 locus can be used as the favorable allele for improving milk protein percentage. Genomic prediction showed that the reliability of genomic estimated breeding values (GEBV) of 6 milk production traits ranged from 0.06 to 0.22, and the correlation between estimated breeding values and GEBV ranged from 0.23 to 0.35. These findings provide useful information to understand the genetic basis of buffalo milk properties and may play a role in accelerating buffalo breeding programs using genomic approaches.

Nasal immunization with inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis for improving ovarian responses and fertility in cross-bred buffaloes

This study was conducted to determine the effect of immunization with inhibin DNA vaccine delivered by attenuated Salmonella choleraesuis on ovarian responses and fertility in cross-bred buffaloes. A total of 134 cross-bred buffaloes were divided into four groups: groups T1 (n = 34), T2 (n = 35) and T3 (n = 31) were nasal immunized twice a day with 10 ml of 1 × 10¹⁰  CFU/ml of the C501 (pVAX-asd-IS) vaccine for 5, 3 and 1 day, respectively. Group C (n = 34) was nasal immunized with 10 ml PBS for 5 days. All animals were immunized twice with an interval of 14 days and administered with 200 μg of a GnRH analogue on day 28, 0.5 mg PGF_2α on day 35 and 200 μg of the same GnRH analogue on day 37. TAI was performed at 18 and 24 hr after the second GnRH treatment. Fourteen days after primary immunization, C501 (pVAX-asd-IS) elicited significant immune responses, and anti-inhibin IgG antibody titres in group T1 were significantly higher (p < .01) than groups T3 and C. After the second GnRH treatment, the growth speed of the dominant follicles in group T1 was significantly faster (p < .05) than groups T3 and C. The number and diameter of large follicles (≥10 mm) as well as ovulatory follicles in group T1 were the greatest in all groups, resulting in a greater conception rate in buffaloes with positive anti-inhibin antibodies. These results demonstrate that immunization with the C501 (pVAX-asd-IS) vaccine, coupled with the Ovsynch protocol, could be used as an alternative approach to improve reproductive performance in cross-bred buffaloes.

Methylation analysis of CXCR1 in mammary gland tissue of cows with mastitis induced by Staphylococcus aureus

Mastitis is the most important disease in the global dairy industry, and causes large economic losses. Staphylococcus aureus is one of most common pathogens that cause bovine mastitis. CXCR1 has been implicated as a prospective genetic marker for mastitis resistance in dairy cows; CXCR1 expression significantly increases when cows have mastitis. To investigate the mechanisms involved in its increased expression, bisulfite sequencing polymerase chain reaction (PCR) was used to detect the methylation status of CXCR1 CpG island, and quantitative fluorescence PCR was used to detect CXCR1 expression in bovine mammary tissue induced with S. aureus in three Chinese Holstein cows. No CpG island was found for bovine CXCR1 in the upstream 2-kb region, whereas one CpG island that contained 13 CpG sites was found in exon 1 of CXCR1. All of the CpG sites were under hypermethylation from 90 to 100% in the mammary tissues. When the mammary gland mRNA expression of CXCR1 was 12.10-fold higher in infected cow quarters than in uninfected quarters, the methylation levels of the CpG site at position 519 were significantly lower in the infected quarters than in the uninfected quarters. Pearson correlation analysis showed that the methylation level at position 519 was significantly negatively correlated with the CXCR1 mRNA expression level (P < 0.05). These results indicate that the methylation of the CpG site at position 519 may regulate CXCR1 expression in cows with mastitis induced by S. aureus, but further studies are needed to elucidate the mechanisms involved.

Differential expression of luteinizing hormone receptor, androgen receptor and heat-shock protein 70 in the testis of long-distance transported mice

Spermatogenesis, is a complex process of precisely regulated intracellular events, where it is affected by many factors. Long-distance transport of animals is one of the stressors that may influence spermatogenesis and sperm quality. The present study chose luteinizing hormone receptor (LHR), androgen receptor (AR), and heat-shock protein 70 (HSP70) as our target genes to investigate their mRNA and protein expression in the testes of long-distance transported (about 1000 km) mice. Histological analysis showed that there was a reduction in the thickness of the seminiferous epithelium in the transported mice, and a significant decrease in body weight and sperm count in the epididymis was also observed. mRNA expression was determined by QPCR in the testis of transported and control mice. The levels for AR decreased significantly in transported mice. LHR and HSP70 expression in the testes of the transported mice was slightly higher than that of control mice but did not reach a significant level. A similar tendency of protein expression was also observed by Western blot analysis. The levels of LHR and HSP70 increased slightly after transportation. However, none of the changes were statistically significant compared with the control mice. In conclusion, long-distance transport has an adverse effect on reproductive organs and spermatozoa in adult mice.

Coding for stable transmission of W-band radio-over-fiber system using direct-beating of two independent lasers

We demonstrate experimentally Manchester (MC) coding based W-band (75 - 110 GHz) radio-over-fiber (ROF) system to reduce the low-frequency-components (LFCs) signal distortion generated by two independent low-cost lasers using spectral shaping. Hence, a low-cost and higher performance W-band ROF system is achieved. In this system, direct-beating of two independent low-cost CW lasers without frequency tracking circuit (FTC) is used to generate the millimeter-wave. Approaches, such as delayed self-heterodyne interferometer and heterodyne beating are performed to characterize the optical-beating-interference sub-terahertz signal (OBIS). Furthermore, W-band ROF systems using MC coding and NRZ-OOK are compared and discussed.

FSHR genotype affects estrogen levels but not pregnancy rates in Luxi cattle subjected to embryo transfer

Follicle-stimulating hormone receptor (FSHR), which mediates the functioning of FSH, plays a central role in reproduction. We investigated bovine FSHR gene polymorphisms and analyzed their relationships with pregnancy rates after embryo transfer and with hormone concentrations on the day of embryo transfer. One reported SNP of FSHR, G-278A, located in the 5'-upstream region, was analyzed and three genotypes (GG, GA and AA) were detected in 132 Luxi cattle recipients. Statistical analysis revealed that recipients with the GG genotype had significantly higher estrogen levels on the day of embryo transfer than did GA and AA genotypes. There were no significant differences in pregnancy rates among genotypes, after embryo transfer. We conclude that variation at these loci of the FSHR gene has no significant effect on pregnancy rates in Luxi cattle.

Polymorphism of the inhibin βA gene and its relationship with superovulation traits in Chinese Holstein cows

Inhibin is a major regulator of secretion of follicle-stimulating hormone, which is involved in follicular development and regulation of steroidogenesis in females. The objectives of this study were to detect polymorphisms of the bovine inhibin beta-A subunit (INHβA) gene and to evaluate its associations with superovulatory responses in 171 Chinese Holstein cows treated for superovulation. Polymerase chain reaction-restricted fragment length polymorphism revealed a C>T transition determining the StyI polymorphism at position 7639 in intron I of the bovine INHβA gene, and three genotypes (CC, CT, and TT) were detected. The frequencies of the three genotypes showed a tendency for CT > TT > CC, and this polymorphism was in Hardy-Weinberg equilibrium. Statistical analysis revealed no significant differences of least square means for superovulation traits among the three genotypes (P > 0.05). These results demonstrate, for the first time, that the detected loci of the INHβA gene have no significant effects on superovulation performance in Chinese Holstein cows.

Effects of polymorphisms in the bovine growth differentiation factor 9 gene on sperm quality in Holstein bulls

Members of the transforming growth factor-β (TGFβ) superfamily are critical regulators of germ cell development that act as extracellular ligands of the signal transduction pathways regulating proliferation, differentiation, apoptosis, and other aspects of cell behavior. Growth differentiation factor 9 (GDF9) is a member of the TGFβ superfamily that plays a critical role in ovarian follicular development and ovulation rate in females; however, its role in the testis has not been well elucidated. Therefore, in this study we investigated the effects of GDF9 mutations on the quality of fresh and frozen semen of Holstein bulls. Two reported single nucleotide polymorphisms of GDF9, A485TA and A625C, were analyzed in 129 Holstein bulls. Analysis of variance revealed that the A485T polymorphism had significant effects on the acrosome integrity rate (P < 0.05), whereas the A625T polymorphism was significantly associated with sperm concentration (P < 0.05). In addition, a significant additive effect on sperm concentration was detected for the A485T polymorphism (P < 0.05), whereas the polymorphisms A485TA and A625C had significant dominant effects on acrosome integrity rate and sperm motility in frozen semen, respectively (P < 0.05). This study is the first to show a significant association of GDF9 with sperm quality traits, and the results implied that GDF9 is involved in the initiation or maintenance of spermatogenesis; however, further verification is needed.

Stable and wavelength-tunable silicon-micro-ring-resonator based erbium-doped fiber laser

In this work, we propose and demonstrate a stable and wavelength-tunable erbium-doped fiber (EDF) ring laser. Here, a silicon-on-insulator (SOI)-based silicon-micro-ring-resonator (SMRR) is used as the wavelength selective element inside the fiber ring cavity. A uniform period grating coupler (GC) is used to couple between the SMRR and single mode fiber (SMF) and serves also as a polarization dependent element in the cavity. The output lasing wavelength of the proposed fiber laser can be tuned at a tuning step of 2 nm (defined by the free spectral range (FSR) of the SMRR) in a bandwidth of 35.2 nm (1532.00 to 1567.20 nm), which is defined by the gain of the EDF. The optical-signal-to-noise-ratio (OSNR) of each lasing wavelength is larger than 42.0 dB. In addition, the output stabilities of power and wavelength are also discussed.

Association of multi-pathogenic infections with BAT2, CXCL12, Mx1 and EHMT2 variations in pigs

Porcine reproductive and respiratory syndrome virus (PRRSV), Haemophilus parasuis and Pseudorabies become a widespread problem causing great economic losses associated with reproductive disturbance, respiratory diseases, neonatal mortality, fibrinous polyserositis, meningitis and arthritis in the pig industry. The important candidate genes are assumed to play crucial roles in host defense against the diseases. The aims of this study were to evaluate the variants in HLA-B associated transcript 2 (BAT2), CXCL12, myxovirus resistance protein 1 (Mx1) and EHMT2 genes and their effects on the risk of infection PRRSV and H. parasuis in a case-control (diseased-healthy pigs) population of Duroc × Landrace × LargeWhite. The results showed that the mutations in BAT2, Mx1 and EHMT2 genes were significantly associated with the antibody and the reisk of infection PRRSV and H. parasuis. Those individuals with AA genotype of BAT2 had significantly higher Pseudorabies virus antibody than that with GG and GA (P < 0.05), and the individuals with TT genotype of EHMT2 generated higher Hog Cholera and Pseudorabies virus antibody than that wtih GG and GA (P < 0.01). These results indicated that the polymorphisms in Mx1, BAT2 and EHMT2 genes changed the diseases susceptibility and could be the potential markers assisting the pig breeding selection and disease resistance.

Effects of FUT1 gene mutation on resistance to infectious disease

Alpha-(1,2)-fucosyltransferase (FUT1) gene has been identified as a candidate gene for regulating the expression of Escherichia coli F18 receptor gene (ECF18R) which promotes adherence of Enterotoxigenic (ETEC) and Verotoxigenic (VTEC) Escherichia coli (E. coli) via F18 fimbriae. In order to illustrate the polymorphisms of FUT1 and their effects on resistance to natural infection by Porcine Respiratory and Reproductive Symdrome Virus (PRRSV) and Haemophilus parasuis, the distributions of different genotypes and the relative risks of disease incidence in pigs were investigated. A total of 1,041 pigs representing three European breeds (Duroc, Landrace and LargeWhite), five Chinese local breeds (Wild pig, Small MeiShan, QinPing, JinHua, and JianLi) and three commercial populations (LargeWhite × JianLi, Duroc × Landrace × LargeWhite and Duroc × wild pig) were selected to analyze the genotype of the FUT1 gene by PCR-RFLP. Only the GG genotype associated with susceptibility to ECF18 bacteria was detected in Chinese local pig breeds and a population of LargeWhite × JianLi, while the AA genotype which confers resistance to ECF18 was detected in two European breeds (Duroc and LargeWhite), two populations of Duroc × wild pig and Duroc × Landrace × LargeWhite. Regarding relative risk of incidence, Duroc × Landrace × LargeWhite with genotypes GG or AG showed greater relative risk (OR = 2.040, P = 0.025; OR = 1.750, P = 0.081, respectively) than those with genotype AA during natural infection by both PRRSV and Haemophilus parasuis. It can be concluded that the mutation of FUT1 gene might play a role in pig infection by multi-pathogens, and that AA may be a favourable genotype for increasing the resistance to disease.

Reproductive performance and survival of Chinese Holstein dairy cows in central China

Fertility and longevity, major factors affecting the economic performance of dairy herds, are influenced by management and genetics. This study determined the reproductive performance and survival of Chinese Holstein cows in a large, modern dairy farm in central China using two complementary datasets. In Dataset 1, fertility and culling records were obtained from 1430 cows calving in 2008; in Dataset 2, all calving episodes during 2005 and 2006 were recorded (n = 1540) and the subsequent survival and reasons for death or culling of all female calves born during this period were monitored. In Dataset 1, the mean ages at first breeding and first calving for heifers were 18.7 ± 2.6 and 29.3 ± 3.6 months, respectively. Cows (lactations 1–10) were first inseminated at 110 ± 49 days after calving (mean ± s.d.), conceived at 185 ± 103 days and required 2.3 ± 1.6 services per conception with a first service conception rate of 34%. Reproduction performance was lower in the first lactation, with the best fertility in autumn-calving cows. In Dataset 2, 601 live-born heifers were monitored from birth until first calving. Of these, 521 (87%) were inseminated at least once and 502 (84%) calved once, but only 68% of the starting population calved successfully for a second time. The main reasons for culling in both datasets were poor fertility, disease and lameness. Improved management strategies to avoid calving cows in the spring and so offset the adverse effects of summer heat stress together with increased emphasis on selection for good fertility and conformation traits would increase future profitability.

Genetic diversity analysis of an indigenous Chinese buffalo breed and hybrids based on microsatellite data

Chinese native buffaloes have faced the threat of extinction, along with an increase in crossbreeding with domesticated river buffaloes; consequently, conservation of local buffalo genetic resources has become a priority. A Chinese native breed, Jianghan, is often crossed intentionally and unintentionally with imported breeds from India and Pakistan, Murrah, and Nili-Ravi. A total of 128 buffaloes of the breeds Jianghan, Murrah, and Nili-Ravi and their presumed hybrid offspring were genotyped for 10 microsatellite markers. Heterozygosity and Wright's F-statistics were calculated to determine the genetic variation in those populations. The observed average heterozygosities ranged from 0.836 (Murrah) to 0.986 (Jianghan), higher than the expected heterozygosities and all the inbreeding values within the populations were negative. The genetic distances between the presumed hybrid buffaloes and the two imported river type dairy buffalo breeds (Murrah and Nili-Ravi) were lower than with the native Jianghan, indicating strong contributions of the imported breeds to this presumed hybrid buffalo population. This information will be useful for the development of rational breeding for the dairy buffalo industry and for conservation strategies for the Jianghan buffalo.

Identification of complex vertebral malformation carriers in Holstein cattle in south China

Complex vertebral malformation (CVM) is a recently described monogenic autosomal recessive hereditary defect of Holstein dairy cattle that causes premature birth, aborted fetuses and stillborn calves. Guanine is substituted by thymine (G>T) in the solute carrier family 35 member A3 gene (SLC35A3). A valine is changed to a phenylalanine at position 180 of uridine 5'-diphosphate-N-acetyl-glucosamine transporter protein. CVM is expected to occur in many countries due to the widespread use of sire semen. We developed a created restriction site PCR (CRS-PCR) method to diagnose CVM in dairy cows. This was tested on 217 cows and 125 bulls selected randomly from a Holstein cattle population in south China. Five Holstein cows and five Holstein bulls were identified to be CVM carriers; the percentages of CVM carriers were estimated to be 2.3, 4.0 and 2.9% in the cows, bulls and entire Holstein cattle sample, respectively.

Association analysis between variants in bovine progesterone receptor gene and superovulation traits in Chinese Holstein cows

The objective of this study was to identify a predictor to forecast superovulation response on the basis of associations between superovulation performance and gene polymorphism. The PCR-RFLP method was applied to detect two reported single nucleotide polymorphisms (SNPs) of G59752C and T81637C (rs41614030) located in introns 3 and 4 of the bovine progesterone receptor (PGR) gene in 171 Chinese Holstein cows treated for superovulation and evaluate its associations with superovulation traits. In polymorphic locus 81637, all cows without superovulation response were g.81637TC and g.81637TT genotypes. Association analysis showed that these two SNPs had significant effects on the total number of ova (TNO) (p<0.05), and the T81637C polymorphism was significantly associated with the number of transferable embryos (p<0.05). In addition, significant additive effects (p<0.05) on TNO were detected in the polymorphisms of G59752C and T81637C. These results showed for the first time that the G59752C and T81637C polymorphisms in PGR gene were associated with superovulation traits and indicated that PGR gene can be used as a predictor for superovulation in Chinese Holstein cows.

Polymorphism of the growth hormone gene and its association with growth traits in Boer goat bucks

In the present study, the polymorphism of growth hormone (GH) gene was analyzed as a genetic marker candidate for growth traits in Boer goat bucks. Two single nucleotide polymorphisms (SNPs) - A781G (Ser/Gly35) and A1575G (Leu147), were identified by GH gene sequencing and PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) analysis. AA genotype resulted in a significant decrease in birth chest girth (P=0.03) and weaning weight (P=0.014) comparing to AB genotype, while CC genotype contributed to weaning height (P=0.04) greater than CD genotype. When in combination, AACD genotype was undesired for lower scores in a series of growth traits including body weight, length, height, and chest girth at birth and weaning, as well as the pre-weaning daily gain and body weight at age of 11 months. These results indicate that new molecular markers associated with caprine growth traits can be used in MAS (marker-assisted selection) in Boer goat bucks.

Identification of mutations of zona pellucida glycoprotein (ZP3) and its association with pig reproductive traits

Reproduction is a complex trait, controlled by genetic and environmental factors. Genetic improvement of this trait is important for animal breeders to improve the animal's production efficiency. Apart from genetic factors, animal production can be affected by environmental factors, i.e. the nursing ability of the sow, which is in turn affected directly by effective teat number (teats producing milk normally, TN) and number of piglets born alive (NBA). The objective of this study was to find new mutations, such as single nucleotide polymorphisms (SNPs) from the Zona Pellucida glycoprotein gene (ZP3) using Single Strand Chain Polymorphism (SSCP) and nucleotide sequencing and to investigate association between genetic variations and sow reproductive traits. We identified 13 new SNPs from exon 1, two new SNPs from intron 2, one SNP from intron 6 and a 18 bp (GCACGTGGTCCTCCTGG)-deletion/insertion from intron 2 of the ZP3 gene. Five out of these mutations were selected to genotype in five different breeds (Small Meishan, Qingping, Duroc, Landrace and Large White) and association with reproductive traits in European breeds (Duroc, Landrace and Large White). The sows with genotype AA had more 1.11 piglets NBA than of the sows with genotype AB (p < 0.05) in the 18 bp deletion/insertion of intron 2, while non-significant associations between the other mutations and reproductive traits (NBA and TN) were found.

Antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in Guangzhou, China, 1996-2001

OBJECTIVE

To investigate the in vitro antimicrobial susceptibility and resistant trends of Neisseria gonorrhoeae strains isolated in Guangzhou, from 1996 to 2001.

METHODS

The agar dilution method was used to determine the minimum inhibitory concentrations (MICs) to four antimicrobials, penicillin G, ciprofloxacin, ceftriaxone, and spectinomycin. The resistance of all strains to four antibiotics was interpreted according to criteria used in the project of surveillance of gonococcal antibiotic susceptibility in the WHO Western Pacific Region. Penicillinase producing N gonorrhoeae (PPNG) was analysed by the paper acidometric method.

RESULTS

793 consecutive N gonorrhoeae isolates collected in Guangzhou were studied from 1996 to 2001. A total of 55 strains of PPNG were identified and the prevalence rapidly spread from 2% to 21.8%. Of the four antibiotics examined, ceftriaxone and spectinomycin appeared to be the most effective agents although two spectinomycin resistant strains were isolated in 1996. Their MIC(50), MIC(90), and geometric mean MIC (MICmean) were all between the sensitive ranges of the interpretative criteria and remained stable over the years. However, resistance increased continuously to penicillin G and dramatically to ciprofloxacin. In 1996-2001, MIC(50), MIC(90), and MICmean of penicillin G increased from 1 micro g/ml to 2 micro g/ml, 4 micro g/ml to 32 micro g/ml, and 0.68 micro g/ml to 2.35 micro g/ml, respectively; those of ciprofloxacin steeply increased from 0.12 micro g/ml to 4 micro g/ml, 2 micro g/ml to 32 micro g/ml, and 0.14 micro g/ml to 2.62 micro g/ml in 1996-9, respectively, and then declined slightly in 2000-1. The prevalence of resistant isolates spread from 57.2% to 81.8% for penicillin G and from 17.6% to 72.7% for ciprofloxacin over the 6 years.

CONCLUSION

Resistance to penicillin and ciprofloxacin increased greatly during 1996-2001. Ceftriaxone and spectinomycin should be used as the first line agents in treating gonorrhoea. It is of great importance to continuously survey the susceptibilities of N gonorrhoeae to antibiotics in controlling the spread of gonococcal infections.

[Anatomical study and clinical application of medial femoral condylar bone flap pedicled with the saphenous vessels]

OBJECTIVE

To investigate a new operative method for repairing nonunion and defect of tibia.

METHODS

First, observe the relation between the joint branches of descending genicular artery and the saphenous branch of descending genicular artery in 10 cadevers. Then the medial femoral condylar bone flap pedicled with the saphenous vessels was prepared in 4 cadavers for simulated purpose. Clinically, two patients with tibial nonunion were treated by transplantation of this pedicled bone flap.

RESULTS

In the 4 simulated operations, the ink which was injected into the femoral artery could be released from the joint branches. And in the clinical operation, the area of the pedicled bone flaps were 5.0 cm x 2.0 cm x 1.5 cm and 4.5 cm x 1.5 cm x 1.5 cm respectively. Followed up for 8 to 12 weeks, the fracture unioned well.

CONCLUSION

This operation is simple and reliable, it is characterised by 1. unnecessary to anastomosis the vessels 2. reliable blood supply 3. high quality of bone flap 4. either bone flap or bone-skin flap can be chosen 5. long vessel pedicle.