Efficiency of ciprofloxacin for bacterial control, post-thaw quality, and in vivo fertility of buffalo spermatozoa

Antibiogram of Microorganisms Isolated from Fresh and Frozen Semen of Crossbred Frieswal Bulls

BACKGROUND: The bacterial contaminants in the semen are a major concern for most of the semen production laboratories because they adversely affect the semen quality. During sperm cryopreservation, the inclusion of antimicrobials in extenders may help to minimize bacterial growth. However, due to bacterial resistance to commonly used antimicrobials, they cannot fully assure microbiological safety to the frozen semen. OBJECTIVE: To estimate the microbial load and antibiogram of microorganisms isolated from the fresh and frozen bull semen. MATERIALS AND METHODS: The bacterial load was estimated in fresh and frozen semen samples of crossbred Frieswal bulls by the pour plate method. Microorganisms were identified as Gram positive and Gram negative by Gram staining. The representative bacterial colonies were streaked onto different specific media which were further confirmed by biochemical tests. Bacterial isolates were subjected to in vitro antibiotic sensitivity test. RESULTS: The average microbial load of fresh and frozen semen samples was found to be 8397.4±524.31 cfu/mL and 680.87±105.41cfu/mL, respectively. Microorganisms belonging to Staphylococcus aureus, Staphylococcus epidermidis, Proteus, Klebsiella, Bacillus cereus, Bacillus subtilis, Actinomyces, E. coli, Rhodococcus, Neisseria and Micrococcus were identified in the semen samples. The antibiotic sensitivity testing of the bacterial isolates revealed that benzyl penicillin was found to be the least effective against the isolated organisms while gentamicin and spectinomycin were found to be most effective among the antibiotics used. Lincomycin, tylosin and streptomycin showed moderate efficacy against the bacterial isolates. CONCLUSION: Gentamicin, tylosin, lincomycin, and spectinomycin (GTLS) antibiotic combination is more effective against bacterial isolates and may be added to semen extender to better control bacterial load and semen quality. .

A systems toxicology approach to explore toxicological mechanisms of fluoroquinolones-induced testis injury

The widespread use of fluoroquinolones (FQs) causes a serious risk to the environment and human health. Here, we evaluated the potential effect to induce testis damage by gatifloxacin (GAT) intragastrically treatment in mice (25, 50, and 100 mg/kg body weight per day for 7 days). We observed testicular weight, serum testosterone, antioxidant enzyme activity, and mRNA levels and pathways. Testicular histopathology indicated that GAT administration induced a dose-dependent spermatogenesis abnormality. At 50 mg/kg, GAT altered gene expression but did not change the weight and the levels of testosterone and antioxidant enzymes. These findings indicate that mRNA levels are more sensitive than weight and testosterone for detecting GAT testicular toxicity. We also found that GAT induced testicular damage by regulating the candidate genes associated with spermatogenesis, germ cell movement, testicular fibrosis, and reproductive axis development. This study enhances our perception of the mechanism of FQs-induced testicular toxicity and environmental effects. However, the molecular mechanism needs to be further researched.

A systematic review and meta-analysis of spermatozoa cryopreservation, in vitro and in vivo fertility practices in water buffalo

We explored different aspects of buffalo spermatozoa during cryopreservation. The meta-data comprised of 285 studies, published from January 2008 to March 2020. A free web tool CADIMA as well as PRISMA 2009 Flow Diagram were used for carrying out this study. The inter-reviewer agreement among studies allocated was satisfactory for criteria A (selection bias), B (performance bias), C (detection bias) and D (attrition bias), respectively. India led the percent (%) research ladder with 34.4, followed by Pakistan (29.5), Egypt (12.3), Iran (7.7), Italy (5.6), Indonesia (3.2), China (2.1), Brazil (1.4), Thailand (1.1), Philippines and Bulgaria (0.7 each), Saudi Arabia, Turkey, Vietnam, and USA (0.4 each). Among four categories of studies, Group-1 evaluated only supplements/additives/media in the freezing semen extender (n = 191/285; 67.02%); Group-2 conducted in vivo fertilization (n = 62/285; 21.75%) and Group-3 conducted in vitro fertilization/ cleavage rate/penetration rate/ blastocyst yields (n = 28/285; 9.82%) with their specific cryodiluents/media, respectively. Group-4 conducted different experimental supplements/additives/media and carried out both in vitro and in vivo fertilization simultaneously (n = 4/285; 1.40%). Conventional spermatozoa cryopreservation was reported by 51.9% studies followed by programmable fast freezing by 20.7% studies. A few leading extender types included BioXcell (3.9%); Soyamilk-skim (3.5%); and Andromed (2.1%). The study also describes French straws for semen filling, cooling temperatures, extension time, equilibration time, cryopreservation stages, thawing temperatures, seasons, thawing time, and stains used during semen evaluation assays. The study concludes that the research on spermatozoa cryopreservation of buffalo is largely conducted at quality level and a need of applying these findings for evaluation of fertility potential (in vivo and in vitro) is indispensable for effective genetic improvement.

Current and alternative trends in antibacterial agents used in mammalian semen technology

The use of antibacterial substances as additives in extenders for ensuring the sanitary quality of the semen employed in reproductive biotechniques and preserving it from bacterial deterioration has been reported since the mid-twentieth century. However, the deleterious effects of these drugs on the sperm quality as well as their effectiveness in controlling bacterial growth in the preserved semen have been questioned. The aim of this review was to report the antimicrobials primarily used in the extenders added to the semen of mammals, and to present alternatives to their use. Among the various mammalian species, there is a large variation regarding the antimicrobial types added to semen extenders as cephalosporins (ceftiofur, cefdinir, eg) and quinolones (ofloxacin, ciprofloxacin), alone or in combination with large action spectra substances as penicillin-streptomycin and gentamicin-tylosin-lincomycin-spectinomycin. To combat problems related to bacterial resistance to these drugs, the emergence of alternatives is increasingly evident. Among these alternatives, use of physical methods as centrifugation and filtration, as well as the use of antimicrobial peptides and other substances from different origins have been highlighted for presenting antimicrobial potential.

Bacteriospermia and Sperm Quality of Cryopreserved Bull Semen Used in Artificial Insemination of Cows in South Wollo Zone, Ethiopia

The objectives of this trial were to estimate prevalence of bacteriospermia, to determine the bacterial load, and to isolate the types of bacteria as well as to assess the association between bacterial load and sperm quality traits in cryopreserved bull semen in field conditions in the South Wollo Zone. A total of 309 cryopreserved straws of semen from the Holstein Friesian (HF)-cross bull (n = 180 straws) and pure Jersey bull (n = 129 straws) were investigated. Bacteriological assessments of the presence of aerobic bacteria, estimation of bacterial count and bacterial isolation, as well as semen quality were performed. Aerobic bacterial contamination was prevalent in 38.8% of the semen straws. No significant difference in the prevalence of bacteriospermia was observed among bulls although the HF-cross bull had a higher prevalence (40.0%). But, significant difference in prevalence of bacteriospermia was found among semen ejaculates of the same bull. The risk of bacteriospermia in the HF-cross bull was higher (Odds ratio = 1.86, 95% CI = 0.168–20.26) compared to Jersey although not significant. Overall average bacterial load of 50.38 ± 16.29 colony-forming units (CFU)/ml (from nil to 1318.20 CFU/ml) was found. No significant difference in bacterial count among bulls and their ejaculates was observed. Moreover, correlation analysis revealed that the proportions of motility, live, and normal morphology were negatively influenced by an increase in the bacterial contamination of semen. In this study, three isolates of coagualse-negative Staphylococcus species and one isolate of Corynebacterium species were found. Average percentages of sperm motility (48.35 ± 1.23), live (66.08 ± 1.0), and normal morphology (80.62 ± 1.24) were observed. It was concluded that cryopreservation does not guarantee the quality of semen from bacterial contamination. Hence, meticulous care should be adopted to prevent contamination of semen by bacteria during collection, transportation, processing, and storage times.

Antibiotic resistance in microorganisms isolated in a bull semen stud

Many microorganisms from various sources may be present in ejaculates of bulls. This study identified and isolated bacteria from bull sperm samples in a commercial stud and evaluated their resistance to antibiotics. The number of colony-forming units was determined in semen samples collected at distinct steps during freezing and thawing. The minimum inhibitory concentration and the minimum bactericidal concentration were determined for four antibiotics commonly used in commercial studs. A total of 135 microorganisms from 25 genera were isolated. After a sensitivity test, all evaluated microorganisms (n = 55) were resistant to penicillin and most of them were resistant to tylosin and lincomycin (n = 54). Resistance to all tested antibiotics was observed in 22% of all isolates, whereas only 3.9% of the isolates were inhibited by the tested antibiotics at the concentrations recommended by the international legislation. As the isolated microorganisms presented high resistance to frequently used antibiotics, sensitivity tests should be periodically conducted in commercial bull semen studs to prevent the use of contaminated semen in artificial insemination.

Effect of ciprofloxacin on biological nitrogen and phosphorus removal from wastewater

In this work, both short-term and long-term experiments were therefore conducted to assess the effects of ciprofloxacin (0.2 and 2mg·L^-1) on wastewater nutrient removal. The results showed that both levels of ciprofloxacin had no acute and chronic adverse effects on the surface integrity and viability of activated sludge. Short-term exposure to all the ciprofloxacin levels induced negligible influences on wastewater nutrient removal. However, the prolonged exposure to ciprofloxacin decreased total phosphorus and nitrogen removal efficiencies from 96.8, 95.8% (control) to 91.7, 84.9% (0.2mg·L^-1) and 90.5%, 80.2% (2mg·L^-1), respectively. The mechanism study showed that ciprofloxacin exposure suppressed denitrification and phosphorus uptake processes. It was also found that ciprofloxacin affected the transformations of intracellular polyhydroxyalkanoates and glycogen in the oxic and anoxic stages. Moreover the activities of nitrite reductase and polyphosphate kinase were inhibited by the presence of ciprofloxacin. Further analysis with high-throughput sequencing revealed that compared with the control, the abundances of polyphosphate accumulating organisms, glycogen accumulating organisms and denitrifying bacteria in ciprofloxacin exposure reactors reduced, which were consistent with the decreased nutrient removal performance measured in these reactors.

Efficiency of antifreeze glycoproteins for cryopreservation of Nili-Ravi (Bubalus bubalis) buffalo bull sperm

Experiments were conducted to evaluate the effect of Antarctic fish antifreeze glycoproteins, (AFGP) size 1-5 (34-10.5 kDa) and 7-8 (3.2 and 2.4 kDa) in extender on buffalo bull sperm at cooling (4 °C) and at post thawing. Semen was collected from three Nili-Ravi buffalo bulls with artificial vagina for 3 weeks. Qualifying ejaculates from each buffalo bull were diluted (at 37 °C having 50×10(6) sperm/mL) in tris-citric acid extender containing AFGP at 0 (control), 0.1, 1 and 10 μg/mL. An aliquot of diluted semen was evaluated for sperm progressive motility and plasma membrane integrity, while the remaining fraction was cooled to 4 °C in 2 h. Further, an aliquot of cooled semen was evaluated for the previously described variables and the remaining fraction was cryopreserved (-196 °C). After 24 h of storage, straws were thawed at 37 °C for 30 s to assess post-thaw sperm quality. Inclusion of AFGP in the extender did not affect (P>0.05) sperm progressive motility and plasma membrane integrity of buffalo bull sperm at cooling stage (4 °C). However, at post thawing, improvement (P<0.05) in sperm progressive motility and plasma membrane integrity was recorded in extender containing AFGP 1-5 and AFGP 7-8 at 1 μg/mL compared to the control. Percentage of live sperm with an intact acrosome remained similar (P>0.05) in extenders containing different amounts of AFGP and control. In conclusion, supplementation of 1 μg/ml of AFGP in extender improved the motility and plasma membrane integrity of Nili-Ravi buffalo sperm after thawing.

The effects of antibiotic additions to extenders on fresh and frozen-thawed bull semen

Reproduction in dairy cows is based around the use of cryopreserved semen. Antibiotics are utilized to control bacterial contamination and growth in cryopreserved bull semen. The antibiotic resistance of some bacteria required the evaluation of new antibiotic combinations with a high level of antibacterial effectiveness and a negligible effect on spermatozoa. In this research, we studied the effect of the fluorinate carboxyquinolone ofloxacin and the combination of ceftiofur/tylosin on bull spermatozoa and in-field bacterial growth. In Experiment 1, the toxicity of different levels of ofloxacin and ceftiofur/tylosin was tested by the incubation of bull spermatozoa and the evaluation of sperm kinetic parameters, membranes and acrosome integrity after dilution, and at 60 and 120 min after incubation. The data reported in this study reveals that both antibiotic combinations, at all concentrations, seem to have a negligible effect on spermatozoa with respect to all of the parameters examined (p>0.05). Furthermore, progressive motility was significantly higher for sperm diluted with both antibiotic combinations compared with samples without antibiotics (p<0.01). In Experiment 2, the ability of ofloxacin or ceftiofur/tylosin to control bacterial growth during bovine semen cryopreservation was compared with the combination of gentamicin/tylosin/spectinomycin/lincomycin. A significant reduction in progressive motility was found in cooled semen with respect to all of the antibiotic treatments (p<0.05). However, the membrane integrity was found to significantly rise in frozen samples with, compared to samples without, antibiotics (p<0.05). In a bull, gentamicin, tylosin, spectinomycin, and lincomycin failed to control bacterial growth in the cryopreserved sample, while no such growth was found in samples extended with ceftiofur/tylosin or ofloxacin. In conclusion, both ceftiofur/tylosin and ofloxacin can be safely added to bull seminal extenders, and both can protect insemination doses from bacteria that are resistant to other antibiotic combinations.