RESUMO
In vitro production (IVP) of embryos in cattle can result in large/abnormal offspring syndrome (LOS/AOS) which is characterized by macrosomia. LOS can cause dystocia and lead to the death of dam and calf. Currently, no test exists to identify LOS pregnancies. We hypothesized that fetal ultrasonography and/or maternal blood markers are useful to identify LOS. Bovine fetuses were generated by artificial insemination (control) or IVP. Fetal ultrasonographies were taken on gestation D55 (D55) and fetal collections performed on D56 or D105 (gestation in cattle ≈ D280). IVP fetuses weighing ≥ 97 percentile of the control weight were considered LOS. Ultrasonography results show that the product of six D55 measurements can be used to identify extreme cases of LOS. To determine whether maternal blood can be used to identify LOS, leukocyte mRNA from 23 females was sequenced. Unsupervised hierarchical clustering grouped the transcriptomes of the two females carrying the two largest LOS fetuses. Comparison of the leukocyte transcriptomes of these two females to the transcriptome of all other females identified several misregulated transcripts on gestation D55 and D105 with LOC783838 and PCDH1 being misregulated at both time-points. Together our data suggest that LOS is identifiable during pregnancy in cattle.
Assuntos
Perfilação da Expressão Gênica , Inseminação Artificial , Animais , Bovinos , Feminino , Feto , Inseminação Artificial/veterinária , Gravidez , Ultrassonografia Pré-NatalRESUMO
CASE DESCRIPTION: 4 alpacas and 2 llamas (11 months to 11 years old) from 2 properties were examined for lethargy (6/6), salivation and regurgitation (4/6), and recumbency (3/6). Signs developed approximately 48 to 72 hours after accidental access to black oil sunflower seeds. CLINICAL FINDINGS: 3 alpacas died suddenly prior to treatment and were necropsied. One llama survived, and 1 alpaca and 1 llama died after days of medical treatment. All 3 treated animals had systemic inflammatory signs including tachycardia, fever, and hematologic changes. Biochemical anomalies included azotemia, hyperglycemia, hyponatremia, hypochloremia, and hypoalbuminemia. Necropsy identified numerous sunflower seeds in the gastrointestinal tract of all 5 animals that died, with pulmonary congestion (5/5 animals), mild centrilobular vacuolar hepatic degeneration (4/5), and erosions of the esophagus (3/5) and first (3/5) and third (1/5) compartments of the forestomach. Renal tubular necrosis was found in the 2 animals that died on day 4 of treatment. TREATMENT AND OUTCOME: One llama responded successfully to intensive medical management including supplemented IV fluid therapy, oral and partial parenteral nutrition, and administration of antimicrobials, furosemide, and insulin and was clinically normal with plasma biochemical analysis values within reference range 12 weeks later. Vitamin D, oxalates, heavy metals, and mycotoxins were excluded as the cause of clinical signs on the basis of screening of uneaten seeds and tissue samples and gastric content from the treated llama that died. CLINICAL RELEVANCE: Inadvertent large volume black oil sunflower seed ingestion resulted in a high mortality rate in camelids. A specific toxic principle was not identified. Feeding this product to camelids is not recommended to avoid the risk of accidental overingestion and subsequent disease.
Assuntos
Azotemia , Camelídeos Americanos , Helianthus , Animais , Azotemia/veterinária , Ingestão de AlimentosRESUMO
BACKGROUND: Gallbladder mucocele is a potentially life-threatening extrahepatic biliary disease in dogs. The primary aims of this study were to evaluate the prevalence of cholecystitis in dogs with gross and histopathologically confirmed gallbladder mucocele and to investigate if there is an association between cholecystitis, including its subtypes (eg, acute, acute on chronic, with necrosis, chronic), and survival. Our secondary objective was to evaluate if there is an association between cholecystitis and intraoperative bacteriological culture positivity. KEY FINDINGS: Two hundred nineteen dogs with gallbladder mucocele were included in this multi-institutional retrospective study, of which 63 (28.8%) dogs had histopathological evidence of cholecystitis. The most common forms of cholecystitis were acute on chronic (n = 22/63, 34.9%) and with necrosis (n = 20, 31.7%). Thirty-one (14.1%) dogs had growth of at least 1 bacterial isolate; however, 88.7% had antimicrobials administered within the 48 hours before surgery or intraoperatively. There was not an association between cholecystitis or its subtypes and survival. Furthermore, there was not an association between cholecystitis and intraoperative bacteriological culture positivity. A total of 38 (17.4%) dogs either died or were euthanized during hospitalization. SIGNIFICANCE: Cholecystitis is a common comorbidity in dogs with gallbladder mucocele but was not associated with decreased survival.
Assuntos
Colecistite/veterinária , Doenças do Cão/epidemiologia , Vesícula Biliar/patologia , Mucocele/veterinária , Animais , Arizona/epidemiologia , Colecistite/epidemiologia , Doenças do Cão/diagnóstico por imagem , Doenças do Cão/patologia , Cães , Feminino , Masculino , Mucocele/complicações , Mucocele/diagnóstico por imagem , Prevalência , Registros/veterinária , Estudos Retrospectivos , Ultrassonografia/veterináriaRESUMO
Mycoplasmosis is a well-known cause of morbidity and mortality in small ruminants. Previously recognized outbreaks have involved arthritis, and pneumonia or pleuropneumonia. Modern bacteriology procedures rely less on isolation techniques that require special media for mollicutes given that these species are notoriously difficult to isolate, and rely more on PCR tests. We report an outbreak of arthritis, pleuropneumonia, and mild meningitis affecting dairy goat kids, spanning a period of 3 y, which had unusual epidemiologic characteristics related to husbandry practices. Lesions were characterized by polyarthritis of the appendicular joints, with copious joint fluid and extension of arthritic exudate beyond the joint itself. The cause remained unknown until serendipitous isolation of a mycoplasma on blood agar. Mycoplasmosis was not detected from synovial samples by a general mycoplasma PCR, despite multiple attempts. Isolated colonies were also negative by this general PCR assay. The isolate was identified as Mycoplasma mycoides subspecies capri, using universal 16S primers and amplicon sequencing. Testing of additional isolates from other diseased goats in the herd confirmed that this was the cause of illness. A failure to recognize the distinct nature of organisms of the M. mycoides group of mycoplasmas meant that a PCR test that cannot detect this group of organisms was utilized at first, and the etiology of the illness was overlooked for a period of time. Veterinary pathologists and microbiologists must be aware of the limitations of some PCR assays when confronted with joint disease and pleuropneumonia in small ruminants.
Assuntos
Artrite/veterinária , Surtos de Doenças/veterinária , Doenças das Cabras/epidemiologia , Meningite/veterinária , Mycoplasma mycoides/isolamento & purificação , Pleuropneumonia Contagiosa/epidemiologia , Criação de Animais Domésticos , Animais , Animais Recém-Nascidos , Artrite/diagnóstico , Artrite/epidemiologia , Artrite/microbiologia , Feminino , Doenças das Cabras/diagnóstico , Doenças das Cabras/microbiologia , Cabras , Incidência , Masculino , Meningite/diagnóstico , Meningite/epidemiologia , Meningite/microbiologia , Missouri/epidemiologia , Pleuropneumonia Contagiosa/diagnóstico , Pleuropneumonia Contagiosa/microbiologiaRESUMO
Reported clinical signs of coccidiosis in South American camelids include anorexia of a few days duration, sudden death, and diarrhea. Antemortem diagnosis of clinical coccidiosis is usually based on clinical signs and supported by detection of coccidial oocysts in feces. This report describes 2 atypical cases of coccidiosis in South American camelids that had no coccidial oocysts detected on antemortem fecal flotation, prolonged weight loss, and normal fecal consistency.
Assuntos
Camelídeos Americanos/parasitologia , Coccidiose/veterinária , Animais , Coccidiose/diagnóstico , Coccidiose/patologia , Eimeria/classificação , Eimeria/isolamento & purificação , Feminino , Íleo/parasitologia , Íleo/patologia , Jejuno/parasitologia , Jejuno/patologia , MasculinoRESUMO
An anorectic response occurs following ingestion of imbalanced amino acid (IMB) diets. There are three phases to this response: 1, recognition of the IMB diet; 2, conditioned development of an aversion to the IMB diet; and 3, adaptation. Blockade of peripheral serotonin-3 (5-HT3) receptors or vagotomy attenuates Phase 2 of the anorectic response. We investigated whether sympathetic efferents interact with the ventral gastric branch (VGB), by cutting it (X), or with the 5-HT3 receptor in these responses. First, VGBX and sham-operated (SHAM) groups were injected with vehicle or phenoxybenzamine (alpha-blocker), or nadolol (beta-blocker) before introducing the IMB diet. At 3 h suppression of the IMB diet ingestion was unchanged, showing no sympathetic efferent effect on Phase 1. Intake of the IMB diet increased 12-24 h later only in the SHAM+phenoxybenzamine group, so the VGB was necessary for alpha-blockade to enhance IMB diet intake during Phase 2 or possibly Phase 3. On days 2-5, intakes by the SHAM+phenoxybenzamine, VGBX+phenoxybenzamine and VGBX+nadolol groups were elevated. Therefore, alpha-blockade enhanced adaptation alone, but VGBX was necessary for beta-receptor blockade to augment Phase 3 adaptation. Both sympathetic efferents and the VGB are involved in Phases 2-3. Second, rats received vehicle or nadolol or scopolamine (nonselective muscarinic blocker) or pirenzepine (muscarinic M-1 receptor blocker),w+/-tropisetron (5-HT3 blocker). Pirenzepine attenuated the tropisetron effect between 6-9 h, but then pirenzepine and nadolol enhanced the tropisetron effect between 9-12 h. Scopolamine attenuated the tropisetron effect between 9-12 h. While neither experiment showed effects during the recognition phase, the autonomic and serotonergic systems interact in the learned and adaptive responses to IMB diets.
Assuntos
Aminoácidos/administração & dosagem , Vias Autônomas/efeitos dos fármacos , Proteínas Alimentares/administração & dosagem , Aminoácidos/toxicidade , Animais , Anorexia/induzido quimicamente , Vias Autônomas/fisiologia , Proteínas Alimentares/toxicidade , Vias Eferentes/efeitos dos fármacos , Vias Eferentes/fisiologia , Masculino , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
A 13-yr-old male Alpaca (Lama pacos) presented with multiple ovoid, well-circumscribed, nonulcerated intradermal masses. Individual masses measured 1-4 cm in diameter, and the overlying skin was alopecic. Several of the masses were surgically removed and evaluated microscopically. Histopathologic evaluation demonstrated multiple dermal cysts lined by neoplastic follicular epithelium. The cysts were filled with multiple layers of lamellar keratin and lined by abortive inner and outer root sheaths exhibiting cellular atypia, supporting the diagnosis of trichoepitheliomas. No additional treatment was initiated, and the alpaca continues to do well.
Assuntos
Camelídeos Americanos , Neoplasias Cutâneas/veterinária , Animais , Animais de Zoológico , Masculino , Neoplasias Primárias Múltiplas/patologia , Neoplasias Primárias Múltiplas/cirurgia , Neoplasias Primárias Múltiplas/ultraestrutura , Neoplasias Primárias Múltiplas/veterinária , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/cirurgia , Neoplasias Cutâneas/ultraestrutura , Resultado do TratamentoRESUMO
An 11-year-old Quarterhorse mare developed a paranasal sinus osteoma that extended into the right orbit and led to ipsilateral exophthalmia. Although the tumor was radiographically evident in the paranasal sinuses, ultrasonography was used to demonstrate extension of the tumor into the retrobulbar space, and endoscopy was used to identify its extension into the nasopharynx. Biopsies were obtained using both fine-needle aspiration and paranasal sinus trephination. Despite numerous antemortem diagnostic tests, only postmortem histologic analysis of the mass afforded the diagnosis of osteoma.
Assuntos
Exoftalmia/veterinária , Doenças dos Cavalos/patologia , Osteoma/veterinária , Neoplasias dos Seios Paranasais/veterinária , Complicações Neoplásicas na Gravidez/veterinária , Animais , Biópsia por Agulha Fina/veterinária , Endoscopia/veterinária , Exoftalmia/etiologia , Exoftalmia/patologia , Evolução Fatal , Feminino , Histocitoquímica/veterinária , Cavalos , Osteoma/patologia , Neoplasias dos Seios Paranasais/patologia , Gravidez , Complicações Neoplásicas na Gravidez/patologiaRESUMO
A pilot-scale study investigating the use of low-pressure, high-intensity UV radiation for disinfection of urban wastewater was conducted. The inactivation of coliform bacteria, wastewater-indigenous enteric viruses, seeded poliovirus, and seeded F-specific coliphage was studied. During the course of the pilot study, infectious human adenoviruses were isolated from 15 of 16 large-volume samples of UV-disinfected secondary- and tertiary-treated wastewater. Half of the tertiary-treated, UV-disinfected effluent samples from which the adenoviruses were isolated had total coliform concentrations that complied with California's Water Recycling Criteria. To determine the relative UV resistance of the adenovirus isolates, purified viruses were seeded into tertiary-treated waste-water and exposed to low-pressure, high-intensity, collimated UV radiation. A dose of approximately 170 mW-s/cm2 was required to achieve 99.99% inactivation. These findings suggest that UV doses effective at meeting certain wastewater regulations for total coliform bacteria may not provide suitable inactivation of the UV-resistant human adenoviruses.
Assuntos
Desinfetantes , Águas Residuárias , Adenovírus Humanos , Bactérias , Desinfecção , Humanos , Projetos Piloto , Raios Ultravioleta , Microbiologia da Água , Purificação da ÁguaRESUMO
Microbiological and histological analysis of a sample from a swollen testicle of a 2-year-old Border Collie dog revealed a mixed infection of the fungus Blastomyces dermatitidis and the Gram-negative bacterium Aureimonas altamirensis. When subjected to an automated microbial identification system, the latter isolate was provisionally identified as Psychrobacter phenylpyruvicus, but the organism shared several biochemical features with Brucella canis and exhibited agglutination, albeit weakly, with anti-B. canis antiserum. Unequivocal identification of the organism was only achieved by 16S ribosomal RNA gene sequencing, ultimately establishing the identity as A. altamirensis. Since its first description in 2006, this organism has been isolated infrequently from human clinical samples, but, to the authors' knowledge, has not been reported from a veterinary clinical sample. While of unknown clinical significance with respect to the pathology observed for the polymicrobial infection described herein, it highlights the critical importance to unambiguously identify the microbe for diagnostic, epidemiological, infection control, and public health purposes.
Assuntos
Alphaproteobacteria/isolamento & purificação , Doenças do Cão/diagnóstico , Doenças do Cão/microbiologia , Edema/veterinária , Infecções por Bactérias Gram-Negativas/veterinária , Doenças Testiculares/veterinária , Alphaproteobacteria/genética , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Cães , Edema/diagnóstico , Edema/microbiologia , Infecções por Bactérias Gram-Negativas/diagnóstico , Infecções por Bactérias Gram-Negativas/microbiologia , Masculino , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Análise de Sequência de DNA/veterinária , Doenças Testiculares/diagnóstico , Doenças Testiculares/microbiologia , Resultado do TratamentoRESUMO
CONTEXT: Germline AIP mutations usually cause young-onset acromegaly with low penetrance in a subset of familial isolated pituitary adenoma families. We describe our experience with a large family with R304* AIP mutation and discuss some of the diagnostic dilemmas and management issues. OBJECTIVE: The aim of the study was to identify and screen mutation carriers in the family. PATIENTS: Forty-three family members participated in the study. SETTING: The study was performed in university hospitals. OUTCOME: We conducted genetic and endocrine screening of family members. RESULTS: We identified 18 carriers of the R304* mutation, three family members with an AIP-variant A299V, and two family members who harbored both changes. One of the two index cases presented with gigantism and pituitary apoplexy, the other presented with young-onset acromegaly, and both had surgery and radiotherapy. After genetic and clinical screening of the family, two R304* carriers were diagnosed with acromegaly. They underwent transsphenoidal surgery after a short period of somatostatin analog treatment. One of these two patients is in remission; the other achieved successful pregnancy despite suboptimal control of acromegaly. One of the A299V carrier family members was previously diagnosed with a microprolactinoma; we consider this case to be a phenocopy. Height of the unaffected R304* carrier family members is not different compared to noncarrier relatives. CONCLUSIONS: Families with AIP mutations present particular problems such as the occurrence of large invasive tumors, poor response to medical treatment, difficulties with fertility and management of pregnancy, and the finding of AIP sequence variants of unknown significance. Because disease mostly develops at a younger age and penetrance is low, the timing and duration of the follow-up of carriers without overt disease requires further study. The psychological and financial impact of prolonged clinical screening must be considered. Excellent relationships between the family, endocrinologists, and geneticists are essential, and ideally these families should be managed in centers with specialist expertise.
Assuntos
Testes Genéticos , Adenoma Hipofisário Secretor de Hormônio do Crescimento/genética , Adenoma Hipofisário Secretor de Hormônio do Crescimento/terapia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Códon sem Sentido , Feminino , Mutação em Linhagem Germinativa , Humanos , Masculino , Linhagem , Gravidez , Adulto JovemAssuntos
Doenças do Cão/diagnóstico , Mastócitos , Neoplasias Nasais/veterinária , Neoplasias Faríngeas/veterinária , Animais , Doenças do Cão/patologia , Cães , Epistaxe/complicações , Epistaxe/veterinária , Feminino , Neoplasias Nasais/diagnóstico , Neoplasias Nasais/patologia , Neoplasias Nasais/fisiopatologia , Neoplasias Faríngeas/diagnóstico , Neoplasias Faríngeas/patologia , Neoplasias Faríngeas/fisiopatologiaAssuntos
Doenças do Cão/diagnóstico , Eutanásia Animal , Mieloma Múltiplo/veterinária , Animais , Análise Química do Sangue/veterinária , Diagnóstico Diferencial , Dirofilaria immitis/isolamento & purificação , Dirofilariose/complicações , Dirofilariose/diagnóstico , Dirofilariose/diagnóstico por imagem , Doenças do Cão/diagnóstico por imagem , Cães , Feminino , Coxeadura Animal/diagnóstico , Coxeadura Animal/diagnóstico por imagem , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/diagnóstico por imagem , RadiografiaRESUMO
BACKGROUND: Employer-sponsored health risk assessments (HRA) may include laboratory tests to provide evidence of disease and disease risks for common medical conditions. We evaluated the ability of HRA-laboratory testing to provide new disease-risk information to participants. METHODOLOGY/PRINCIPAL FINDINGS: We performed a cross-sectional analysis of HRA-laboratory results for participating adult employees and their eligible spouses or their domestic partners, focusing on three common health conditions: hyperlipidemia, diabetes mellitus, and chronic kidney disease. HRA with laboratory results of 52,270 first-time participants were analyzed. Nearly all participants had access to health insurance coverage. Twenty-four percent (12,392) self-reported one or more of these medical conditions: 21.1% (11,017) self-identified as having hyperlipidemia, 4.7% (2,479) self-identified as having diabetes, and 0.7% (352) self-identified as having chronic kidney disease. Overall, 36% (nâ=â18,540) of participants had laboratory evidence of at least one medical condition newly identified: 30.7% (16,032) had laboratory evidence of hyperlipidemia identified, 1.9% (984) had laboratory evidence of diabetes identified, and 5.5% (2,866) had laboratory evidence of chronic kidney disease identified. Of all participants with evidence of hyperlipidemia 59% (16,030 of 27,047), were newly identified through the HRA. Among those with evidence of diabetes 28% (984 of 3,463) were newly identified. The highest rate of newly identified disease risk was for chronic kidney disease: 89% (2,866 of 3,218) of participants with evidence of this condition had not self-reported it. Men (39%) were more likely than women (33%) to have at least one newly identified condition (p<0.0001). Among men, lower levels of educational achievement were associated with modestly higher rates of newly identified disease risk (p<0.0001); the association with educational achievement among women was unclear. Even among the youngest age range (20 to 29 year olds), nearly 1 in 4 participants (24%) had a newly identified risk for disease. CONCLUSIONS/SIGNIFICANCE: These results support the important role of employer-sponsored laboratory testing as an integral element of HRA for identifying evidence of previously undiagnosed common medical conditions in individuals of all working age ranges, regardless of educational level and gender.
Assuntos
Programas de Rastreamento/métodos , Saúde Ocupacional/normas , Adulto , Química Clínica/métodos , Estudos Transversais , Diabetes Mellitus/sangue , Diabetes Mellitus/diagnóstico , Feminino , Humanos , Hiperlipidemias/sangue , Hiperlipidemias/diagnóstico , Falência Renal Crônica/sangue , Falência Renal Crônica/diagnóstico , Masculino , Pessoa de Meia-Idade , Prevalência , Risco , Medição de Risco , Estados Unidos , Local de TrabalhoRESUMO
OBJECTIVE: To describe and evaluate a technique for radical resection of the lateral body wall for treatment of fibrosarcoma with reconstruction using polypropylene mesh and a caudal superficial epigastric axial pattern flap in cats. STUDY DESIGN: Prospective, clinical study. ANIMALS OR SAMPLE POPULATION: Six client-owned cats with fibrosarcoma. METHODS: Six cats with histologically confirmed fibrosarcoma of the lateral body wall were staged using radiography and/or computer tomography scanning. Preoperative radiotherapy was used in 3 cats. All cats had the lateral abdominal wall resected and reconstructed with polypropylene mesh. A caudal superficial epigastric flap was mobilized and rotated to close the skin deficit. The animals were evaluated after surgery for wound complications, tumor recurrence, and metastasis. Outcome was assessed by patient examination and client consultation. RESULTS: Minor dehiscence of the skin flaps occurred in 2 cats, and 1 other cat was successfully resuscitated from respiratory and cardiac arrest after surgery. All tissue specimens were tumor-free at the surgical margins. Follow-up times ranged from 12 to 21 months, with a mean time of 17.2 months. None of the cats had evidence of local tumor recurrence or metastasis; outcome was judged good to excellent in all cats. CONCLUSIONS AND CLINICAL RELEVANCE: Radical lateral body-wall resection and reconstruction is an effective technique for achieving local tumor control with acceptable patient morbidity. Further studies are needed to assess whether the technique will result in improved tumor-free intervals and survival times.
Assuntos
Abdome , Doenças do Gato/cirurgia , Fibrossarcoma/veterinária , Neoplasias Musculares/veterinária , Retalhos Cirúrgicos/veterinária , Animais , Gatos , Feminino , Fibrossarcoma/diagnóstico por imagem , Fibrossarcoma/cirurgia , Masculino , Neoplasias Musculares/diagnóstico por imagem , Neoplasias Musculares/cirurgia , Polipropilenos , Estudos Prospectivos , Radiografia , Cirurgia Veterinária/métodos , Suturas , Resultado do Tratamento , CicatrizaçãoRESUMO
Previous studies showed that levels as low as 0.1% sodium ultraphosphate (UP), 0.1% sodium polyphosphate glassy (SPG) and 0.5% tetrasodium pyrophosphate (TSPP) were bactericidal and bacteriolytic to early-exponential phase cells of Staphylococcus aureus ISP40 8325. In the present study, Ca2+ (0.01 M) or Mg2+ (0.01 M) reversed the bacteriolytic effects of UP (0.1%) and SPG (0.1%) to S. aureus . In addition, Ca2+ (0.01 M) or Mg2+ (0.01 M), when added to the culture medium before inoculation, protected cells from growth inhibition by UP and SPG. Moreover, the bactericidal effects of UP or SPG were reversed by Ca2+ or Mg2+ in metal-rescue experiments in which the metals were added to polyphosphate-containing medium after 1 h of incubation. No additive effect existed between Mg2+ and Ca2+. Growth inhibition of TSPP was not reversed by Mg2+ or Ca2+, but it was reversed by Fe3+ when Fe3+ was added to protect cells 1 h before the addition of TSPP. These studies show that the antibacterial effects of phosphates can be altered substantially by the metal-ion content of the environment.
RESUMO
Phosphates have been approved for use in meat products primarily to protect flavor and increase yields. It also is known that phosphates have antimicrobial properties. The objective of this study was to compare the effects of different phosphates in a model system. Minimum inhibitory concentrations (MICs) of selected food-grade phosphates added to early-exponential-phase cells of Staphylococcus aureus ISP40 8325 in a synthetic medium were determined to be 0.1% for sodium ultraphosphate and sodium polyphosphate glassy and 0.5% for sodium acid pyrophosphate, sodium tripolyphosphate and tetrasodium pyrophosphate. Thus, the MIC values for the very long chain-length phosphates were lower than the MIC values for shorter chain-length phosphates. Leakage of intracellular nucleotides was observed both spectrophotometrically (release of A260-absorbing material) and microscopically (appearance of gelatinous cellular aggregates). Treatment of the gelatinous cellular aggregates with DNase, RNase and proteinase indicated that the aggregates contained DNA, RNA and protein, thus indicating cellular lysis in the presence of phosphates.
RESUMO
The results of previous studies indicated that the antibacterial effects of long-chain polyphosphates (sodium polyphosphate glassy [SPG] and sodium ultraphosphate [UP]) to Staphylococcus aureus ISP40 8325 could be attributed to damage to the cell envelope (cell wall or cell membrane). Also, Ca2+ (0.01 M) or Mg2+ (0.01 M) reversed the bactericidal and bacteriolytic effects of polyphosphates in S. aureus . In the present study, 0.4 M sodium chloride (NaCl) protected the cells from leakage caused by SPG and 0.6 M NaCl protected the cells from leakage by UP. Polymyxin, a peptide antibiotic that causes cell membrane damage, induced leakage even in the presence of 0.6 M NaCl. In the presence of 0.4 M NaCl, bacterial leakage was significantly reduced by disodium ethylenediamine tetraacetate (EDTA), a metal chelator that causes cell wall damage. Bacterial leakage by polyphosphates was significantly greater at pH 8 than at pH 6, which suggested that metal-ion chelation was involved in the antibacterial mechanism. A dialysis membrane (MWCO 100) was used to separate free metal and polyphosphate-bound metal. Levels of free Ca2+ and Mg2+ in polyphosphate-treated cells were significantly lower than those of the cells without polyphosphate. This free-metal dialysis study provided Chemical evidence to show that long-chain polyphosphates interacted with S. aureus cell walls by a metal-ion chelation mechanism. In addition, long-chain polyphosphates were shown to bind to the cell wall, chelate metals, and remain bound without releasing metal ions from the cell wall into the suspending medium. A hypothesis is proposed in which the antibacterial mechanism of long-chain polyphosphates is caused by binding of long-chain polyphosphates to the cell wall of early-exponential phase cells of S. aureus ISP40 8325. The polyphosphates chelate structurally essential metals (Ca2+ and Mg2+) of the cell wall, resulting in bactericidal and bacteriolytic effects. The structurally essential metals probably form cross bridges between the teichoic acid chains in the cell walls of gram-positive bacteria.