99 Increased expression of microRNAs in sperm of Nelore Bulls with high invitro fertility

The spermatozoon is no longer known only as a cell that delivers the male genetic material to the oocyte, because it also provides molecules such as microRNAs (miRNAs) that play a significant role in fertilization and embryonic development. MiRNAs are small noncoding RNAs capable of modulating mRNA translation, thus affecting important biological processes. Sperm miRNAs may influence embryo development and therefore, might be related to invitro production of embryos (IVP), considering that individual bulls have different fertility rates when used for IVF. The aim of this work was to identify miRNAs expressed in semen of bulls with high and low IVP rates. The composition of groups was based on a retrospective database from a reproductive biotechnology company between the years of 2016 and 2018, generating around 7000 IVP manipulations of 430 Nelore bulls. We only considered IVP manipulations that used a minimum of 30 oocytes and conventional semen selection by Percoll gradient. A total of 87 Nelore bulls fit these criteria. We then ranked bulls based on cleavage rate (number of cleaved structures/number of oocytes), blastocyst rate (number of blastocysts/number of oocytes) and embryo development rate (number of blastocysts/number of cleaved structures). Considering these three rates, we allocated bulls to two groups. The top eight were considered to have high IVP fertility (HF) and the bottom eight were grouped together as low IVP fertility (LF). We performed the T TEST procedure (SAS 9.3 software; SAS Institute Inc.) to compare the groups for cleavage (P<0.0001), blastocyst (P=0.0006), and embryo development (P=0.0001) rates. For miRNA analysis, sperm were separated using Percoll gradient and subjected to RNA extraction and cDNA synthesis. First, quantitative real-time PCR was used to evaluate the abundance of 380 bovine-specific miRNAs in a pool of samples for each group, using QuantStudio 6Flex. Then, 48 miRNAs presenting at least a 3-fold change of normalized cycle threshold values between groups were selected: 23 highly detected in HF, 1 highly detected in LF, 18 exclusively detected in HF, and 2 exclusively detected in LF. Last, we evaluated the abundance of these selected miRNAs in each experimental unit. We identified four miRNAs highly abundant in sperm from HF bulls, bta-miR-10a, bta-miR-383, bta-miR-93, and bta-miR-449b. Our results suggest that these miRNAs could play important roles in bovine embryo development. This work was supported by FAPESP (grant# 2018/03871-6).

Detection of protamine 2 in bovine spermatozoa and testicles

BACKGROUND

Sperm DNA integrity is crucial for transmission of genetic information to future generations and DNA damage can occur during chromatin packaging. Chromatin packaging involves the replacement of somatic nucleosomal histones by nuclear proteins called protamines. Protamine 1 (PRM1) is transcribed and translated in spermatids of all mammals; however, protamine 2 (PRM2) is transcribed in low levels in spermatids and it is not yet described in bull mature spermatozoa.

OBJECTIVES

The aim of this study was to assess gene and protein expression of PRM2 and corroborate gene and protein expression of PRM1 in bull spermatozoa and testis.

MATERIALS AND METHODS

For this purpose, absolute q-RT-PCR was performed to calculate the number of copies of PRM1 and PRM2 mRNAs in bovine epididymal spermatozoa and testicular tissue. Western blot and mass spectrometry were performed to identify PRM1 and PRM2 in samples of bovine epididymal spermatozoa. Samples of bovine testicular tissue were collected to identify PRM1 and PRM2 by immunohistochemistry.

RESULTS

We evaluated that the number of PRM1 mRNA copies was about hundred times higher than PRM2 mRNA copies in sperm and testicular samples (p < 0.0001). In addition, we estimated the PRM1: PRM2 ratio based on mRNA number of copies. In spermatozoa, the ratio was 1: 0.014, and in testicle, the ratio was 1: 0.009. We also evaluated the immunolocalization for PRM1 and PRM2 in bovine testis, and both proteins were detected in spermatids. Western blot and mass spectrometry in bovine epididymal spermatozoa confirmed these results.

CONCLUSION

Our work identifies, for the first time, PRM2 in bovine epididymal spermatozoa and in testis. Further studies are still needed to understand the role of PRM2 on the chromatin of the spermatozoa and to verify how possible changes in PRM2 levels may influence the bull fertility.

Effect of mitochondrial uncoupling and glycolysis inhibition on ram sperm functionality

Studies have demonstrated the importance of mitochondria to sperm functionality, as the main source of ATP for cellular homoeostasis and motility. However, the role of mitochondria on sperm metabolism is still controversial. Studies indicate that, for some species, glycolysis may be the main mechanism for sperm energy production. For ram sperm, such pathway is not clear. Thus, we evaluated ram sperm in response to mitochondrial uncoupling and glycolysis inhibition aiming to assess the importance of each pathway for sperm functionality. Statistical analysis was performed by the SAS System for Windows, using the General Linear Model Procedure. Data were tested for residue normality and variance homogeneity. A p < .05 was considered significant. Groups treated with the mitochondrial uncoupler Carbonyl cyanide 3 chlorophenylhydrazone (CCCP) showed a decrease in the percentage of cells with low mitochondrial activity and high mitochondrial membrane potential. We also observed that the highest CCCP concentration promotes a decrease in sperm susceptibility to lipid peroxidation. Regardless the lack of effect of CCCP on total motility, this substance induced significant alterations on sperm kinetics. Besides the interference of CCCP on spermatic movement patterns, it was also possible to observe such an effect in samples treated with the inhibitor of glycolysis (2-deoxy-d-glucose, DOG). Furthermore, treatment with DOG also led to a dose-dependent increase in sperm susceptibility to lipid peroxidation. Based on our results, we suggest that the glycolysis appears to be as important as oxidative phosphorylation for ovine sperm kinetics as this mechanism is capable of maintaining full motility when most of the cells have a low mitochondrial membrane potential. Furthermore, we found that changes in the glycolytic pathway trough glycolysis inhibition are likely involved in mitochondrial dysfunction and sperm oxidative unbalance.

Sperm cryodamage occurs after rapid freezing phase: flow cytometry approach and antioxidant enzymes activity at different stages of cryopreservation

Background

In order to improve the efficiency of bovine sperm cryopreservation process, it is important to understand how spermatozoa respond to differences in temperature as well as the ability to recover its own metabolism. The combination between flow cytometry approach and antioxidant enzymes activity allows a more sensible evaluation of sperm cell during cryopreservation. The aim of this study was to evaluate sperm attributes and antioxidant enzymes activity during different stages of cryopreservation process. Semen samples from Holstein bulls (n = 4) were separated in 3 treatments: fresh (37 °C); cooled (5 °C); and thawed. Evaluation occurred at 0 h and 2 h after incubation. Membrane integrity, mitochondrial membrane potential (MMP) and DNA damages were evaluated by flow cytometry; activities of antioxidant enzymes such as catalase, superoxide dismutase and gluthatione peroxidase were measured by spectrofotometry.

Results

There was an increase in the percentage of sperm with DNA damage in the thawed group, compared to fresh and cooled, and for 2 hs of incubation when compared to 0 h. Considering MMP, there was an increase in the percentage of cells with medium potential in thawed group when compared to fresh and cooled groups. Opposingly, a decrease was observed in the thawed group considering high mitochondrial potential. Also in the thawed group, there was an increase on cells with damaged acrosome and membrane when compared to fresh and cooled groups. Significant correlations were found between antioxidant enzymes activity and membrane or mitochondrial parameters.

Conclusion

Based on our results, we conclude that cryopreservation affects cellular and DNA integrity and that the critical moment is when sperm cells are exposed to freezing temperature. Also, our study indicates that intracellular antioxidant machinery (SOD and GPX enzymes) is not enough to control cryodamage.

Corrigendum to: 198 AGE EFFECT ON RELATIVE GENE EXPRESSION OF BOVINE SPERMATOGONIA

Spermatogonial stem cells (SSCs) have important applications in treatments for infertility and animal transgenesis. However, the isolation of bovine SSCs is less efficient than for other species and it is lower for adult bulls. The goal of this study was to verify whether the relative gene expression of spermatogonia is affected by age after the laminin differential plating. Ten grams of parenchyma of testicles from pre-pubertal animals (5 months of age, n = 5) and bulls (3–4 years of age, n = 5) were minced and digested: colagenase (1 mg mL–1) for 30 min at 37°C and trypsin (2.5 mg mL–1) for 5 min at 37°C. Cells were plated (3 × 106 viable cells) in 60-mm culture dish covered with laminin (20 ng mL–1) and they were cultured for 15 min in high-humidity atmosphere with 5% of CO2 at 37°C. The adherent cells were recovered by enzymatic digestion with 0.1% trypsin for 1 min at 37°C. Viable cells were selected by the Trypan exclusion method, RNA was extracted from ~200.000 viable cells (Ilustra RNAspin Mini RNA, GE Healthcare, Waukesha, WI, USA) and cDNA synthesis was performed (SuperScript® VILO™, Invitrogen, Carlsbad, CA, USA). ITGA6 (integrin, α 6), SELP (Selectin P) and ICAM (Intercellular Adhesion Molecule 1) relative gene expression were determined by real-time RT-PCR (Mastercycler ep Realplex, Eppendorf International, Hamburg, Germany); GAPDH (Glyceraldehyde 3-phosphate dehydrogenase) and ACTB (actin β) were used as housekeeping genes. The statistical analysis was performed by QPCR_MIXED (SAS®, SAS Institute Inc., Cary, NC, USA). An α level at 0.05 was always adopted. ITGA6 and ICAM1 relative expression weren't effected by age; respectively, P = 0.2367 and P = 0.3583. However, SELP was highly expressed in adult bulls (P = 0.0022). Previously, ICAM1 and SELP have also been shown to mark aging haematopoietic stem cells and were more highly expressed in spermatogonia from adult mice than younger. However, SELP is expressed in more differentiated spermatogenic cells such as human sperm. The expression levels of ITGA6 did not seem to be significantly altered by age, indicating that age affects only certain SSC properties. Financial support was provided by FAPESP (CEUA/FMVZ/USP 2509/2011).

Corrigendum to: 198 AGE EFFECT ON RELATIVE GENE EXPRESSION OF BOVINE SPERMATOGONIA

Spermatogonial stem cells (SSCs) have important applications in treatments for infertility and animal transgenesis. However, the isolation of bovine SSCs is less efficient than for other species and it is lower for adult bulls. The goal of this study was to verify whether the relative gene expression of spermatogonia is affected by age after the laminin differential plating. Ten grams of parenchyma of testicles from pre-pubertal animals (5 months of age, n = 5) and bulls (3–4 years of age, n = 5) were minced and digested: colagenase (1 mg mL–1) for 30 min at 37°C and trypsin (2.5 mg mL–1) for 5 min at 37°C. Cells were plated (3 × 106 viable cells) in 60-mm culture dish covered with laminin (20 ng mL–1) and they were cultured for 15 min in high-humidity atmosphere with 5% of CO2 at 37°C. The adherent cells were recovered by enzymatic digestion with 0.1% trypsin for 1 min at 37°C. Viable cells were selected by the Trypan exclusion method, RNA was extracted from ~200.000 viable cells (Ilustra RNAspin Mini RNA, GE Healthcare, Waukesha, WI, USA) and cDNA synthesis was performed (SuperScript® VILO™, Invitrogen, Carlsbad, CA, USA). ITGA6 (integrin, α 6), SELP (Selectin P) and ICAM (Intercellular Adhesion Molecule 1) relative gene expression were determined by real-time RT-PCR (Mastercycler ep Realplex, Eppendorf International, Hamburg, Germany); GAPDH (Glyceraldehyde 3-phosphate dehydrogenase) and ACTB (actin β) were used as housekeeping genes. The statistical analysis was performed by QPCR_MIXED (SAS®, SAS Institute Inc., Cary, NC, USA). An α level at 0.05 was always adopted. ITGA6 and ICAM1 relative expression weren't effected by age; respectively, P = 0.2367 and P = 0.3583. However, SELP was highly expressed in adult bulls (P = 0.0022). Previously, ICAM1 and SELP have also been shown to mark aging haematopoietic stem cells and were more highly expressed in spermatogonia from adult mice than younger. However, SELP is expressed in more differentiated spermatogenic cells such as human sperm. The expression levels of ITGA6 did not seem to be significantly altered by age, indicating that age affects only certain SSC properties. Financial support was provided by FAPESP (CEUA/FMVZ/USP 2509/2011).

319 VALIDATION OF THE CARBOXYFLUORESCEIN DIACETATE ASSOCIATED WITH PROPIDIUM IODIDE FOR MURINE SPERM ACROSOME AND PLASMA MEMBRANE INTEGRITY

The spermatozoa is an ideal vehicle for genetic modification, production of transgenic animals, as well as a biotechnological tool for sperm-mediated gene transfer. However, in order to achieve successful sperm fertilization and exogenous DNA integration, it is necessary for viable cells to remain intact, allowing the sperm to penetrate the oocyte. Fluorescent probes allow evaluation of morphological and functional characteristics of cells, which can be evaluated separately or simultaneously. Therefore, the aim of this study was to validate the simultaneous evaluation of the integrity of plasma and acrosomal membranes of murine sperm using the probes carboxyfluorescein diacetate (CF) and propidium iodide (PI). In order to validate, a standard curve was performed. Sperm were obtained from epididymis and vas deferens from CD-1 mice (8 to 16 weeks of age). Recovered samples were diluted in PBS and then divided into 2 aliquots: one prepared with fresh semen (FS) and the other submitted to Percoll gradient (45%/90%) followed by flash-freezing in liquid nitrogen and thawing (FTP) to induce acrosome damage. Samples were prepared with the following average of FS:FTP: 100:0 (T100), 50 : 50 (T50), and 0 : 100 (T0). Samples were stained using 2 μL Hoescht 33342 (40 μLmL-1 in Dulbecco’s phosphate buffered saline), 3 μL of PI (0.5 mg mL-1 in PBS), 3 μL of CF (0.46 mg mL-1 in DMSO), and were incubated for 8 min at room temperature. After staining, the samples were placed on a slide, coverslipped, and evaluated immediately by epifluorescent microscopy. The Hoescht, PI, and CF fluorescence was detected using a filter with excitation at 352, 538, and 495 nm and emission at 455, 617, and 517 nm, respectively. Approximately 200 sperm cells per slide were examined and classified based on the fluorescence emitted from each probe. Spermatozoa CF+/IP- were considered as intact membranes, CF+/PI+ as acrosome membrane intact and plasma damaged, CF-/PI+ as damaged membranes, and CF-/PI- as acrosome membrane damaged and plasma intact. Hoeschst was used as positive dye. This experiment was replicated 6 times per group, and for statistical analyses, the data of plasma and acrosomal membrane integrity (dependent variables) in the treatments T0, T50, and T100 (independent variables) were submitted to simple linear regression analysis by STATVIEW software (SAS Institute Inc., Cary, NC, USA). The CFDA/PI probes were suitable for the analysis of acrosomal and membrane status of murine sperm and showed a high determination coefficient to plasma membrane integrity (R2 = 0.81; Y = 0.5412x + 6.375) and acrosome integrity (R2 = 0.85; Y = 0.5653x + 11.653). The described protocol was efficient for the simultaneous evaluation of plasma and acrosomal membrane integrity of murine spermatozoa, proving that CFDA can be employed to access acrosomal integrity as an alternative to FITC-PSA. Financial support: FAPESP.

353 CUMULUS CELLS RESPONSE TO HEAT SHOCK AND INSULIN-LIKE GROWTH FACTOR-I

Heat-stress induced maternal hyperthermia has been shown to compromise the series of events associated with oocyte growth and maturation reducing oocyte competence. Such events are regulated by a variety of growth factors and dynamic communication between the oocyte and its surrounding cumulus cells. The objective of the current study was to evaluate the modulatory effects of COCs quality and IGF-I on mitochondrial membrane potential (MMP) and apoptosis in cumulus cells induced by heat shock. In this study high (≥3 layers of compact cumulus cells and homogeneous cytoplasm) and low-grade COCs (<3 layers of less compact cumulus cells and irregular cytoplasm) derived from slaughterhouse ovaries were exposed to control (CTR: 39°C) or heat shock (HS: 41°C) treatments in the presence of 0 or 100 ng mL-1 IGF-I during the first 12 h of in vitro maturation (12 h-IVM). Immediately after 12 h-IVM COCs were denuded by repeated pipetting and cumulus cells evaluated for MMP (MitoProbe JC-1 assay kit. JC-1 is a cationic dye that exhibits potential-depend accumulation in the mitochondria) and apoptosis (Annexin V-FITC and propidium iodide) by flow cytometry (Guava EasyCyte Mini Flow Cytometry System, Millipore, Billerica, MA, USA). This factorial experiment was replicated 4 times using 75-100 COCs per treatment. Data were subjected to three-way analysis of variance using the General Linear Models procedure of SAS. Results are shown in Table 1. Exposure of high and low-grade COCs to HS reduced (P < 0.01) the percentage of cumulus cells carrying high MMP regardless of IGF-I. Even though HS caused cumulus cells mitochondrial membrane depolarization there was neither temperature nor COCs quality effect on cumulus cells apoptosis as indicated by the lack of phosphatidylserine (PS) translocation from the inner to the outer leaflet of the plasma membrane. On the other hand, addition of IGF-I to maturation medium reduced (P < 0.05) the percentage of cumulus cells labeled with Annexin V + PI regardless of COCs quality or temperature. There was no statistical interaction between COCs quality × IGF-I × temperature. In conclusion, exposure of COCs to HS during 12 h-IVM caused cumulus cells mitochondrial depolarization without inducing apoptosis. It is possible that a period longer than 12 h is required for most PS translocation to occur in cumulus cells. Moreover, IGF-I exerted protective effect reducing cumulus cells late apoptosis/necrosis events. Table 1.Effect of heat-shock and IGF-I on cumulus cells mitochondrial membrane potential and apoptosis. Results are least-squares means ± SEM.

230 COMPARISON OF SEMEN SAMPLES FROM NORMAL AND MUSCULAR DYSTROPHY AFFECTED ANIMAL MODELS BY THIOBARBITURIC ACID REACTIVE SUBSTANCES TEST AND FLUORESCENCE-ACTIVATED CELL SORTING ANALYSIS

Duchenne’s muscular dystrophy (DMD) is the most common human muscular affliction with high frequency in male individuals. The condition is characterized by progressive muscle degeneration, weakness, and loss of motion capacity. These individuals exhibit longer lifespans resulting from improvements in technical patient care and now raise new questions ranging from ethical to physiological issues never observed before, such as the possibility of reproduction. Thus, this study used Golden Retriever muscular dystrophy (GRMD)-affected dogs, a natural experimental model of DMD, to evaluate semen quality and oxidative stress by thiobarbituric acid reactive substances (TBARS) test. Thirty-seven ejaculates from 4 non-affected Golden Retriever and 5 GRMD-affected dogs (from 1.5 to 4.5 years old) were collected monthly and evaluated as 5 different replicates. Semen samples were processed, and initial analysis comprised of sperm concentration, percent of straightforward motility and morphology. Samples were then diluted to a final concentration of 106 spermatozoa mL–1 of prior incubation with each fluorescent probe. Acrosome integrity assessment was conducted with PSAFITC (100 g mL–1), and mitochondrial activity was assessed by JC1 (50 g mL–1). Fluorescence-activated cell sorting was performed in 103 spermatozoa, from a pre-selected gate that contained only these cells. Seminal plasma was submitted to TBARS quantification by spectrophotometer under normal and oxidative conditions (stress). Parametric data were compared by Student’s t-test. There were no significant differences in ejaculate volume, sperm concentration, acrosomal integrity, mithocondrial activity, and ejaculate TBARS tests between GRMD and normal dogs. Data are summarized in the table. GRMD does not affect the production and quality of semen of dogs. This animal model suggests that ejaculates from DMD men can be obtained by the proper stimulation and that conventional in vitro fertilization techniques combined with preimplantation genetic diagnosis for single gene disorders may be able to satisfy the desire of paternity of DMD patients with the birth of non-affected children. Table 1.Sperm analysis and TBARS tests of ejaculates from GRMD and normal dogs FAPESP for the financial support (06/50272-3); Surgery Department and Reproduction Department of FMVZ-USP; Canil GRMD Brazil.

276 EXPRESSION OF CD9 AND ALPHA6-INTEGRIN IN PORCINE BLASTOCYSTS

Establishment of embryonic stem cell (ESC) culture in pigs has not been achieved. Verification of pluripotency markers is necessary for validation of a pluripotent cell line. Not all markers observed in ESC from other species are characterized in swine embryos. The objective of this study was to characterize CD9 and α6-integrin expression in porcine blastocysts and to derive porcine ESC using Matrigel. In vitro or in vivo porcine blastocysts were submitted to total RNA extraction for RT-PCR, fixation for immunocytochemistry or immunosurgery for culture of inner cell mass. Expression of Oct-4, CD9, and α6-integrin was detected by PCR. CD9 and α6-integrin PCR products had their nucleotide sequence assessed and compared with public nucleotide database. CD9 product was identical to CD9 porcine sequences and α6-integrin product was similar to human and equine α6-integrin. Immunocytochemistry revealed Oct-4 expression in cytoplasm of the inner cell mass (ICM) and trophoblast cells. CD9 and α6-integrin were observed preferentially on trophoblast cells. No ESC colonies were obtained using co-culture on mouse embryonic fibroblasts (MEF) or on Matrigel. This study describes for the first time expression of CD9 and α6-integrin in porcine blastocysts. Financial support: Fapesp 05/57314-0.

Morphological changes in mouse embryos cryopreserved by different techniques

Cryopreservation of mammalian embryos is an important tool for the application of reproductive biotechnologies. Subjective evaluation to determine embryo viability is often used. The determination of the best cryopreservation protocol depends on morphological and molecular analysis of cellular injuries. The main objective of this study was to compare two methods of cryopreservation by assessing morphological alterations of frozen embryos using light, fluorescence, and transmission electron microscope. Fresh (control), slow frozen, and vitrified mouse embryos were composed. To evaluate the viability of the embryos, the cell membrane integrity was assessed using Hoechst33342 and propidium iodide (H/PI) staining. Morphological analyses using hematoxylin and eosin (HE) staining were performed to test different techniques (in situ, paraffin, and historesin) by both light and fluorescence microscopy. Transmission electron microscope was used to detect ultrastructural alterations in Spurr- and Araldite-embedded samples. H/PI staining detected more membrane permeability in the vitrification (69.8%) than in the slow freezing (48.4%) or control (13.8%) groups (P < 0.001). Historesin-embedded samples showed to be more suitable for morphological analyses because cellular structures were better identified. Nuclear evaluation in historesin sections showed the induction of pycnosis in slow freezing and vitrification groups. Cytoplasm evaluation revealed a condensation and an increase in eosinophilic intensity (indicating apoptosis) in the slow freezing group, and weakly eosinophilic structures and degenerated cells (indicating oncosis) in the vitrification group (P < 0.05). Ultrastructural analyses confirmed HE morphological findings. It was concluded that both cryopreservation techniques resulted in oncosis and apoptosis injuries. However, vitrification caused more severe cellular alterations and reduced embryonic viability compared to slow freezing.

4 MYOSTATIN GENE KNOCKDOWN THROUGH LENTIVIRAL VECTOR-MEDIATED DELIVERY OF shRNA FOR IN VITRO PRODUCTION OF TRANSGENIC BOVINE EMBRYOS

The main goal of husbandry and beef cattle production is to enhance performance rates, for example, weight gain. Myostatin is referred to as a negative regulator of skeletal muscle growth. Genetic engineering of this character in order to produce double muscling animals that can transmit to future progeny will enhance its usefulness. The present research aimed to analyze myostatin inhibition through lentiviral-mediated delivery of shRNA in mouse myoblast culture and the feasibility of the lentiviral-mediated delivery of shRNA into in vitro-produced transgenic bovine embryos. In order to achieve knockdown of myostatin in cell and embryo culture, a lentiviral vector was constructed with ubiquitin C promoter-driven GFP gene (green fluorescent protein) and shRNA to suppress myostatin gene expression driven by the U6 promoter. Vector efficiency was verified through in vitro murine myoblast (C2C12) cell morphology after inductive differentiation and by means of real-time PCR of myostatin and GAPDH genes. Later, bovine oocytes were in vitro-matured and the lentiviral vector was microinjected into the oocyte perivitelline space (2.5 � 106 IU mL-1) after mechanical and chemical cumulus cell removal. Non-microinjected mature oocytes were considered as control. After microinjection, oocytes were fertilized and cultured in vitro. After 4 and 9 days of culture, embryos were evaluated by epifluorescence microscopy. The GFP-positive embryos were green under fluorescence. Cell morphology and embryo development rate data were analyzed by Minitab Release 14 Statistical Software (Minitab, Inc., State College, PA, USA), submitted to ANOVA, and compared by Tukey test (P d 0.05). Real-time PCR data were analyzed by Pair-Wise Fixed Reallocation Randomization Test using REST2005 software. Cell morphology results demonstrated that the vector was able to inhibit myostatin mRNA in C2C12 cells as the transducted group progressed less to myotubes than in the control group. A lower amount of myostatin mRNA after 72 h of differentiation indicated an inhibition tendency by real-time PCR. In relation to the transgenic embryo production, 96.9 � 0.34% (62.65) developed to cleavage, 80.24 � 4.38% (51/65) were GFP-positive, and 50.95 � 3.37% (26/65) achieved blastocyst stage. After hatching, 3.07% (2/65) of GFP-positive embryos maintained fluorescence. In relation to the control group, the cleavage rate was 93.81 � 0.68% (61/65); the blastocyst rate 38.34 � 2.36% (25/65), and none were fluorescent. In conclusion, myostatin gene knockdown was effectively performed by lentiviral vector-mediated delivery of shRNA. Thus, novel studies about the efficiency of this vector on transgenic embryo production can be performed. This work was supported financially by FAPESP 03/0156-9.

270 APOPTOSIS AND ONCOSIS ASSESSMENT IN CRYOPRESERVED MOUSE EMBRYOS

Cryopreservation of mammalian embryos is an important tool for the application of reproductive biotechnology. Recent evidence indicates that apoptosis of cryopreserved embryos may be a negative factor for their viability. The aim of this study was to detect apoptosis and to characterize and quantify the embryonic cell death caused by cryopreservation. Mouse morulae were separated to be subjected to two cryopreservation protocols (slow freezing and vitrification) and a control group (fresh). In the slow-freezing procedure, embryos were exposed to 10% ethylene glycol (EG) for 10 min. Straws were placed in a methanol bath at -7�C until it reached -31�C and then plunged and stored in liquid nitrogen. The embryos were thawed in air for 10 s and in a 25�C water bath for 20 s. In the vitrification method, embryos were exposed to 10% and 20% EG for 5 min, followed by 40% EG + 18% Ficoll + 10% sucrose (EFS) for 30 s and then plunged and stored in liquid nitrogen. These embryos were thawed in a 25�C water bath for 20 s. For the cell death evaluation, cell membrane integrity from the fresh and cryopreserved embryos was assessed by Hoechst and propidium iodide (H/PI staining). Morphology and apoptosis were assessed by means of the haematoxylin-eosin staining (HE) and by electron microscopy (MET). To confirm apoptosis, 64 cryopreserved mouse morulae (34 submitted to slow freezing and 30 to vitrification) were used to evaluate Caspase-3 activity. The cryopreserved embryos were divided into experimental and control groups and incubated with Caspase-3 and buffer solution, respectively. Afterward, the embryos were incubated with rhodamine and the Caspase activity was determined under a fluorescence microscope. H/PI staining detected more membrane permeability in the vitrification (69.7%) than in the slow-freezing (48.4%) or fresh (13.8%) groups (P < 0.05; Wilcoxon's test). Nuclear evaluation by HE revealed that vitrification and slow freezing induced pyknosis and chromatin condensation. HE staining revealed weakly staining cytoplasm and degenerated cells in the vitrification group (indicating oncosis), whereas in the slow-freezing the presence of cytoplasmic condensation and eosinophilic structures indicating apoptosis were observed. MET examination of the ultrastructure confirmed the HE results. The Caspase-3 activity showed a fluorescence increase in both experimental groups compared with the control group. In conclusion, staining with HE allows detection of oncosis and apoptosis in cryopreserved embryos. Regarding the cryopreservation techniques, both slow freezing and vitrification showed oncosis and apoptosis injuries. However, in this experiment vitrification caused more cellular injuries, with less embryo viability, than slow freezing. This work was supported by FAPESP 04/01252-4 and CAPES.

315 EFFICIENCY OF CHEMICAL OR ELECTRICAL ACTIVATION OF BOVINE OOCYTES

Activation of in vitro matured oocytes is essential for the success of nuclear transfer embryo production. Oocyte activation is promoted by the release of intracellular calcium and influx of extracellular ions, and can be chemically induced by calcium ionophores such as A23187 (CA) or ionomycin (IO). Electrical stimulation (EL) is an essential stage in nuclear transfer protocols for the fusion of enucleated oocytes with the donor's cell nucleus. Moreover, EL can be used as an alternative method to induce calcium influx through the formation of pores in the plasma membrane. This work aimed to evaluate the effect of electrical pulse vs the use of different calcium ionophores (A23187 or ionomycin) as primary agents of bovine oocyte activation, with or without the addition of BSA, on the rate of blastocyst formation and blastocyst quality. BSA was used to quench the activation process after a 5-min exposure to CA or IO. Cumulus-oocyte complexes were matured in TCM-199 medium with FCS and hormones for 18 h at 38.5�C and 5% CO2 in air. After removal of cumulus cells, oocytes presenting the first polar body were selected and maintained in SOFaa medium to complete 24 h of maturation. They were then divided into five treatments groups 1-CA (CA 5 mM, 5 min); 2-CAB (CA 5 mM, 5 min; BSA, 5 min); 3-IO (IO 5 mM, 5 min); 4-IOB (IO 5 mM, 5 min; BSA, 5 min); and 5-EL (EL 1.5 kV/cm, 20 �s, 2 pulses). After treatments, oocytes were kept in 6-dimethylaminopurine for 3 h and cultured in SOFaa medium for 7 days at 38.5�C and 5% CO2 in air. Rates of cleavage and blastocyst were evaluated respectively on Days 2 and 7 of culture. To evaluate embryo quality, Hoechst 33342/propidium iodide staining was used. Data were evaluated by ANOVA and submitted to LSD test for embryo rates and t-test for embryo quality. Four replicates were carried out with a total of 89 oocytes per treatment. There was a difference (P < 0.05) in rate of development to blastocyst between treatments 1-CA (54.4%a), 3-IO (51.4%a), and 5-EL (54.5%a) compared with 4-IOB (18.3%b). Treatment 2-CAB (39.8%ab) did not show any difference from the others. There was no difference (P > 0.05) among treatments in total number of cells: 1-CA (63.1a), 2-CAB (57.2a), 3-IO (60.9a), 4-IOB (72.4a), and 5-EL (58.4a). However, there was a difference (P < 0.01) in the percentage of viable cells between treatments 1-CA (49.9%a), 2-CAB (45.8%a), 3-IO (64.9%a), and 4-IOB (50.9%a) in comparison to 5-EL (82.7%b). In conclusion, BSA, when associated with IO, had a negative effect on embryonic developmental rates. The different calcium ionophores used and the BSA did not improve embryo quality. Although there were no significant differences between electrical and chemical activation on the rate of blastocyst formation, it is important to point out that higher quality embryos were achieved by using electrical activation. This work was supported by FAPESP 03/00156-9.

Production of a cloned calf from a fetal fibroblast cell line

The present study examined the in vitro and in vivo development of bovine nuclear-transferred embryos. A bovine fetal fibroblast culture was established and used as nucleus donor. Slaughterhouse oocytes were matured in vitro for 18 h before enucleation. Enucleated oocytes were fused with fetal fibroblasts with an electric stimulus and treated with cytochalasin D and cycloheximide for 1 h followed by cycloheximide alone for 4 h. Reconstructed embryos were cultured for 7-9 days and those which developed to blastocysts were transferred to recipient cows. Of 191 enucleated oocytes, 83 (43.5%) were successfully fused and 24 (28.9%) developed to blastocysts. Eighteen freshly cloned blastocysts were transferred to 14 recipients, 5 (27.8%) of which were pregnant on day 35 and 3 (16.7%) on day 90. Of the three cows that reached the third trimester, one recipient died of hydrallantois 2 months before term, one aborted fetus was recovered at 8 months of gestation, and one delivered by cesarian section a healthy cloned calf. Today, the cloned calf is 15 months old and presents normal body development (378 kg) and sexual behavior (libido and semen characteristics).

Environmental contamination by multidrug-resistant Acinetobacter baumannii in an intensive care unit

Contamination in an intensive care unit caused by multidrug-resistant Acinetobacter baumannii complex (MRAB)-colonized patients was evaluated using environmental and patient cultures. MRAB occurred in 21% of patients' cultures, 2.1% of 513 areas surrounding MRAB-patients, and one of 372 common areas. No transmission to other patients occurred. Barrier precautions and ethanol disinfection may prevent dissemination.

In vitro susceptibility of gram-positive cocci isolated from skin and respiratory tract to azithromycin and twelve other antimicrobial agents

This study was conducted to evaluate the activity of azithromycin in comparison to 12 other antibacterial agents against recent isolates obtained consecutively from patients with respiratory tract or skin infections, from January to July, 2000. A total of 717 Gram-positive cocci were analyzed in this study and the following species were studied: Staphylococcus aureus (n=576), beta-hemolytic streptococci (n=115), and Streptococcus pneumoniae (n=26). Susceptibility testing was carried out by the disk diffusion method and interpreted according to NCCLS breakpoints. The activity of azithromycin was compared to erythromycin, clindamycin, chloramphenicol, ciprofloxacin, ofloxacin, oxacillin, penicillin, ceftriaxone, tetracycline, trimethoprim/sulfamethoxazole, teicoplanin, and vancomycin. Of the 26 S. pneumoniae isolates recovered from the respiratory tract, 5 (19.2%) were intermediate resistant to penicillin. All of these strains were susceptible to chloramphenicol, ofloxacin, and vancomycin, and 24 (92%) were also susceptible to azithromycin, clindamycin, and erythromycin. Among the 67 beta-hemolytic streptococci strains isolated from the respiratory tract, 66 (99%) were susceptible to azithromycin, erythromycin, clindamycin, and ofloxacin. All 48 beta-hemolytic streptococci strains isolated from skin were susceptible to azithromycin and clindamycin, 47 (98%) were susceptible to erythromycin, and 46 (96%) were susceptible to ofloxacin. Of the 576 strains of S. aureus, 253 (43.9%) were isolated from the respiratory tract and 323 (56.1%) from skin. Among S. aureus isolates from the respiratory tract and skin, 46 (18%) and 78 (24%), respectively were resistant to oxacillin. Isolates from the respiratory tract and skin showed the same percentage of resistance (36%) to azithromycin. These in vitro results suggest that azithromycin can be a therapeutic option for treatment of infections caused by these bacteria since the newer macrolides have several distinct advantages over erytromycin including improved oral bioavailability, longer half-life allowing once or twice daily administration, higher tissue concentrations and less gastrointestinal adverse effects.

In vitro activity of fluoroquinolones (gatifloxacin, levofloxacin and trovafloxacin) and seven other antibiotics against Streptococcus pneumoniae

In recent years, the level of resistance of S. pneumoniae to beta-lactam and/or macrolides has increased around the world including some countries in South America. Because of this resistance, it is necessary to test the therapeutic alternatives for treating this pathogen, including the newer quinolones. This study was carried out in order to compare the in vitro activity of fluoroquinolones gatifloxacin, levofloxacin and trovafloxacin, to penicillin G, amoxicillin, amoxicillin-clavulanate, cufuroxime sodium, ceftriaxone, azithromycin and clarithromycin, against 300 strains of S. pneumoniae. Of the 300 samples tested, 18.6% were not susceptible to penicillin (56 strains) and 7% (21 strains) were resistant to the second generation cephalosporin. Among the macrolides, resistance ranged from 6.7% for clarithromycin to 29.6% for azithromycin. Susceptibility to the newer quinolones was 100% including the 56 strains not susceptible to penicillin. Among the 10 antibiotics evaluated, the fluoroquinolones gatifloxacin, levofloxacin, and trovafloxacin displayed high levels of in vitro activity against S. pneumoniae.

Left ventricular mass and function in young obese women

OBJECTIVE

Obesity is associated with a high mortality rate due to cardiovascular disease. Left ventricular (LV) hypertrophy has been described in relation to obesity. The aim of this study was to evaluate echocardiographically the LV mass and function in young obese women as compared to lean women with similar characteristics.

DESIGN

Prospective study.

SUBJECTS

Eighty-two young women (< or =40 y), with obesity degree varying from I to III (BMI from 30 to 50 kg/m2) were compared to eighty young lean women. All of them were normotensive, none had cardiovascular complaints or any previous history of pulmonary disease, and none were taking any medication. The LV mass was calculated by the Devereux and Reichek formula.

RESULTS

The LV mass was strongly increased in all obese groups (P<0.00003 to 0.000005) compared to lean subjects. LV mass adjusted indexes for height, BMI or volume were also increased compared to lean subjects and when adjusted for weight it was decreased. However when comparing LV mass/body surface area index this difference was not statistically significant. The linear regression analysis showed a strong association between the degree of obesity and LV mass, (r=0.52, P<0.001). Systolic and diastolic function in obese patients were similar to lean subjects, except for a lower E/A ratio in the obese group (P=0.005).

CONCLUSION

In asymptomatic young obese women, there are some echocardiographic findings suggesting early cardiac involvement that seems to be related to the degree of obesity.

Whipple's disease. Report of five cases with different clinical features

Whipple's disease (WD) is a rare systemic disease of infectious etiology which involves the small intestine but can virtually affect any organ. We present here five cases (four males and one female) ranging in age from 20 to 59 years. All patients had intestinal involvement associated or not with clinical manifestations linked to this organ. Vegetation in the tricuspid valve was observed in one patient, suggesting endocarditis caused by Tropheryma whippelii, with disappearance of the echocardiographic alterations after treatment. In one of the male patients the initial clinical manifestation was serologically negative spondylitis, with no diarrhea occurring at any time during follow-up. Ocular involvement associated with intestinal malabsorption and significant weight loss were observed in one case. In the other two cases, diarrhea was the major clinical manifestation. All patients were diagnosed by histological examination of the jejunal mucosa and, when indicated, of extraintestinal tissues by light and electron microscopy. After antibiotic treatment, full remission of symptoms occurred in all cases. A control examination of the intestinal mucosa performed after twelve months of treatment with sulfamethoxazole-trimethoprim revealed the disappearance of T. whippelii in four patients. The remaining patient was lost to follow-up.

Nosocomial infections caused by multiresistant Pseudomonas aeruginosa

A case-control study was done to evaluate factors associated with nosocomial infections by multiresistant Pseudomonas aeruginosa (MRPA). Results showed that MRPA was associated with the use of immunosuppressive and antimicrobial drugs. Five typing methods indicated that the MRPA infections were due to multiple strains rather than a single strain.

[In vitro antimicrobial activity of cefpirome compared to other broad-spectrum beta-lactam drugs against 804 clinical isolates from 9 Brazilian hospitals]

OBJECTIVE

To evaluate the in vitro activity of the fourth-generation cephalosporin cefpirome in comparison to that of ceftazidime, ceftriaxone, cefotaxime and imipenem in a multicenter study involving nine hospitals from six cities (four States).

MATERIAL AND METHOD

A total of 804 isolates from patients hospitalized in either intensive care units or Oncology/Hematology units was evaluated. The isolates were collected between June and November of 1995, i.e. before cefpirome became commercially available in Brazil, and susceptibility tested by broth microdilution following the NCCLS procedures. All isolates resistant to cefpirome were retested by E-test.

RESULTS

Against Enterobacteriaceae (n = 344), cefpirome demonstrated an activity 2 to 32-fold higher than that of the third-generation cephalosporins (TGCs) and similar to that of imipenem. The percentages of Enterobacteriaceae susceptible were: 88%, 69% and 96% for cefpirome, TGCs and imipenem, respectively. The cefpirome spectrum was greater or equal than that of imipenem against Citrobacter freundii, Enterobacter aerogenes, Morganella morganii and Serratia marcescens. Against Acinetobacter sp. (n = 77), cefpirome was slightly more active than ceftazidime; however, the percentages of isolates resistant to these compounds were high (84% and 88%, respectively). The activities of cefpirome, ceftazidime and imipenem were very similar against P. aeruginosa isolates (n = 128), with MIC50(mg/ml)/percent susceptible of 8/59%, 8/62% and 4/62% respectively. Against aerobic gram-positive bacteria, the cefpirome activity was 4 to 16-fold higher than that of TGCs but 2 to 8-fold lower than that of imipenem.

CONCLUSION

The results suggest that, in Brazil, cefpirome has a spectrum of activity which is higher than that of the TGCs against aerobic gram-negative (Enterobacteriaceae and non-Enterobacteriaceae) and gram-positive bacteria and similar to that of imipenem against some Enterobacteriaceae species and P. aeruginosa.

Evaluation of the in vitro activity of cefepime compared to other broad-spectrum cephalosporins against clinical isolates from eighteen Brazilian hospitals by using the Etest

The in vitro activity of cefepime was compared to that of ceftazidime, ceftriaxone, and cefotaxime in a multicenter study involving 10 clinical microbiology laboratories and clinical isolates from 18 Brazilian hospitals from 7 cities (4 states). A total of 982 isolates consecutively collected between December 1995 and March 1996 were susceptibility tested by using Etest and following the NCCLS procedures for agar diffusion tests. The cefepime spectrum was broader than that of the other broad-spectrum cephalosporins against both Gram-negative rods and Gram-positive cocci. Cefepime was particularly more active against Enterobacter sp. (MIC90, 2 micrograms/ml), Serratia sp. (MIC90, 2 micrograms/ml) and oxacillin-susceptible Staphylococcus aureus (MIC90, 3 micrograms/ml). Against Pseudomonas aeruginosa, cefepime (MIC90, 16 micrograms/ml) was slightly more active than ceftazidime (MIC90, 32 micrograms/ml) and 8- to 16-fold more active than ceftriaxone of cefotaxime (MIC90, > 256 micrograms/ml). Our results show that nosocomial bacteria, especially Gram-negative rods, have a high rate of cephalosporin resistance in Brazil. However, part of these resistant bacteria remains susceptible to cefepime. The Etest was shown to be an excellent method for multicenter studies of the in vitro evaluation of new antimicrobial agents.

[In vitro activity of cefetamet compared with other antimicrobial agents against bacteria isolated from respiratory tract infections]

Cefetamet pivoxil is a new beta lactamase orally stable administered cephalosporin. Antimicrobial resistance among respiratory pathogens has become an important problem for both the physician and the microbiologist and the patterns of resistance vary greatly depending on geographic location, often requiring in vitro susceptibility testing of isolates.

PURPOSE

The in vitro activity of cefetamet, the microbiologically active metabolite of the prodrug cefetamet pivoxil, was compared with other 11 drugs against 376 bacterial strains recently isolated from patients with respiratory tract infections.

METHODS

The comparative activity in vitro of cefetamet and other 11 antimicrobial agents was measured against 376 bacterial strains isolated from patients with respiratory tract infections, during a six month period. Through the determination of minimum inhibitory concentration by the microdilution technique, patterns of antimicrobial resistance were reported.

RESULTS

Cefetamet showed high in vitro activity against all the bacterial tested, possessing a spectrum of activity similar to that other recently developed oral cephalosporins. The good activity of cefetamet against beta-lactamase producing isolates, like Moraxella catarrhalis, can be due to its beta-lactamase stability. At a concentration of 1.0 microgram/mL, cefetamet inhibited 97% of all the tested bacteria.

CONCLUSION

The MIC90 of the cumulative susceptibility results of the 12 antimicrobics tested in the 376 strains studied, confirm the excellent activity of cefetamet against the common respiratory tract pathogens.

In vitro activity of ampicillin-sulbactam against clinical multiresistant Acinetobacter baumannii isolates

We evaluated the in vitro activity of ampicillin-sulbactam in comparison with that of broad-spectrum antimicrobial agents against Acinetobacter baumannii isolates. Two hundred and twelve clinical isolates collected between January 1993 and March 1995 from two tertiary hospitals located in São Paulo, Brazil were tested for susceptibility by the disk diffusion method against several broad-spectrum antimicrobial agents, including imipenem, ciprofloxacin, ceftazidime, aztreonam, amikacin, and polymyxin B. All strains were susceptible to polymyxin B. The second most active compound was the combination ampicillin-sulbactam (88% susceptibility). Only 79% of the isolates were susceptible to imipenem. Ciprofloxacin was active against 60 (28%) and amikacin against 34 (16%) isolates. Ceftazidime was the most active cephalosporin; however, only 9% of the isolates were susceptible to this compound. Both aztreonam and ampicillin alone showed very poor activity against this species (1% susceptibility). The prevalence of severe infections due to A. baumannii is increasing very rapidly in the tertiary hospitals of São Paulo and there are very few options for the treatment of these infections. Polymyxin B is invariably in vitro active against this species; however, this compound can cause severe side effects and is not commercially available for intravenous use in Brazil and in several other countries. Our results indicated that the combination ampicillin-sulbactam may be an alternative drug for the treatment of infections due to multiresistant A. baumannii; however, further studies are necessary to evaluate the clinical role of this compound for the treatment of severe infections.

[Study of the susceptibility of Staphylococcus sp. and Enterococcus sp. to teicoplanin and vancomycin]

PURPOSE

The study was performed in order to evaluate the susceptibility of Enterococcus and Staphylococcus to teicoplanin and vancomycin.

METHODS

150 Enterococcus strains and 450 Staphylococcus strains (298 Staphylococcus aureus and 152 negative coagulase strains) isolated in three Brazilian hospitals were studied. The MICs were determined using teicoplanin and vancomycin E Test strips. The range of the antimicrobial concentration in each strip went from 256 mcg/mL to 0.016 mcg/mL. Diffusion tests using disks impregnated with 10 mcg of teicoplanin and 30 mcg of vancomycin were also performed.

RESULTS

All the 298 Staphylococcus aureus strains were susceptible to the two antimicrobials. Three of the 152 negative coagulase strains presented intermediate susceptibility to teicoplanin (MICs between 8 and 16 mcg/mL). Four of the 150 Enterococcus strains presented intermediate susceptibility to vancomycin but were totally susceptible to teicoplanin.

CONCLUSION

According to these results teicoplanin and vancomycin are good therapeutical options in the treatment of staphylococcal and enterococcal infections.

An outbreak of multiresistant Acinetobacter baumanii in a university hospital in São Paulo, Brazil

A case-control (46 cases, 23 controls) study was done to determine risk factors for an outbreak of a multiresistant Acinetobacter baumanii (only susceptible to colistin) in a university hospital. The use of antecedent antibacterials and intubation were independent risk factors. No common source was found. With control measures, the outbreak resolved gradually.

Epidemiologic investigation of an outbreak of coagulase-negative Staphylococcus primary bacteremia in a newborn intensive care unit

Infections due to coagulase-negative Staphylococcus (CNS) are an ever-increasing nosocomial problem, particularly in the pediatric population. The authors describe a cluster of three primary bloodstream infections due to CNS in a newborn intensive care unit that occurred between November 23 and December 2, 1992. Two children died as a direct consequence of the bacteremia; at autopsy, one had a large bacteria-containing thrombus extending from the insertion site of a central catheter to the superior vena cava. The children were placed in isolation, and the nursing and medical staff were given topical nasal mupirocin. Plasmid analysis performed later disclosed three different blood isolates that also were different from any of the staff's nasal isolates. The authors concluded that molecular methods such as plasmid analysis are important tools in identifying true outbreaks and can prevent needless interventions, such as those during this cluster.

[Abdominal aortic aneurysm infected with Campylobacter fetus spp fetus. Report of a case and review of the literature]

Aortic aneurysm infected with Campylobacter fetus spp fetus is rare, the first case having been reported in 1971. We present a case of abdominal aortic aneurysm, with a history of abdominal pain, fever and chills, with identification of this gram negative bacillus in the culture of the aortic wall and visualization of the microorganism in histological examination. Surgical correction was performed by interposition of a dracon prosthetic graft. The patient had a good postoperative course, receiving prolonged antibiotic therapy (intravenous cephalothin for 7 days and oral erythromycin for 6 months), remaining without symptoms for 12 months, when the follow-up was ended. In the 11 cases reported in the literature, 9 presented fever, suggesting the infectious etiology. Four were operated on with the aneurysm already ruptured and all of them died. The other patients, with non-ruptured aneurysms at the time of the operation, were all symptomatic, and they survived. Anatomic reconstruction was performed in 4 cases, with dacron graft interposition and antibioticotherapy, without reported signs of infection on the follow-up (6 to 45 months). Aortic infection with Campylobacter fetus spp fetus is potentially fatal, needing immediate surgical treatment. It is possible to have good long term results with an anatomically placed prosthetic graft and antibiotic therapy.

Electric showers as a control measure for Legionella spp. in a renal transplant unit in São Paulo, Brazil. Legionellosis Study Team

After an outbreak of legionnaires' disease Legionella pneumophila serogroup 1 in a renal transplant unit in São Paulo, Brazil, periodic hyperchlorination and flushing of pipes were instituted as control measures. These were only partially effective as every two to five months water cultures turned positive or new cases of the disease occurred. In November 1993 the hot water was disconnected from the unit and small, plastic electric showers were installed in each bathroom. Over a period of 12 months water from showers and taps was cultured for Legionella spp. every two weeks. On only one occasion was a water culture positive for L. pneumophila from a sink tap. No water sample obtained from showers was positive during the study period. No cases of legionnaires' disease occurred. We considered the use of electric showers an inexpensive and effective method of controlling the problem of Legionella spp. in the water system of our renal transplant unit.

[Hospital bacteremia at the "Instituto do Coração do Hospital das Clínicas da FMUSP": a four-year retrospective study]

We conducted a retrospective study to establish mortality rates and prevalence of nosocomial bacteremias at our institute. We found 1.21 nosocomial bacteremias per 100 hospital discharges with an overall Mortality rate of 29.5%. Primary bacteremias increased during the four-year-study-period from 31 to 41%. Staphylococcus, both coagulase-positive and coagulase-negative, was the bacteria most frequently isolated. An abrupt increase in the isolation of P.aeruginosa occurred in 1992. We concluded that a blood-culture surveillance program is required for determining an endemic rate.

[Teicoplanin and vancomycin susceptibility in Staphylococcus aureus and coagulase-negative staphylococci]

Members of the genera Staphylococcus are the most common pathogens found in the hospital environment and they are acquiring resistance to multiple drugs. PURPOSE--To evaluate the in vitro activity of teicoplanin and vancomycin against 195 strains of staphylococci isolated from in-patients. METHODS--One hundred strains of Staphylococcus aureus (50% methicillin-resistant) and 95 strains of coagulase-negative staphylococci (46.3% strains methicillin-resistant) were tested by the agar dilution and the disk diffusion techniques. RESULTS--All strains (100%) were susceptible to vancomycin, S. aureus strains presented MIC90 of 0.5 microgram/mL whereas strains of coagulase-negative staphylococci showed MIC90 of 1.0 microgram/mL. For teicoplanin, 98.5% of the strains were susceptible. MIC90 values were 0.5 microgram/mL for S. aureus strains, 2.0 micrograms/mL for coagulase-negative methicillin-susceptible staphylococci strains and 8.0 micrograms/mL for coagulase-negative methicillin-resistant staphylococci strains. CONCLUSION--From the microbiological point of view, the results showed a high potential for both drugs as therapeutic agents in staphylococcal infections due to multiresistant strains of hospital origin.

An outbreak of nosocomial Legionnaires' disease in a renal transplant unit in São Paulo, Brazil. Legionellosis Study Team

From June 1989 to March 1990 there were eight cases of Legionnaires' disease caused by Legionella pneumophila serogroup 1 in a renal transplant unit. There were seven cases of pneumonia and one case of pleural effusion. A study was conducted to identify the source of the outbreak. Legionella anisa was cultured from tap water. Twenty-seven staff members of the unit were serologically tested and antibody titres were positive in two. The probable source of infection was the potable water system. Control measures were hyperchlorination and heating of the water, after which there were no further cases during 5 months' follow up. We believe this is the first reported Legionnaires' disease outbreak in Latin America.

[In vitro susceptibility to a new antimicrobial agent (imipenem) of pathogens isolated from inpatients at various centers]

Imipenem is a beta lactam antibiotic, a highly potent new carbapenem with broad antibacterial spectrum. To test the "in vitro" efficacy of this antimicrobial agent in pathogens more frequent in several Medical Centers in Brazil, susceptibility testing with 10 mcg imipenem disks and, or corresponding MIC were carried out with 1231 recent isolates of 41 different bacterial species, obtained mainly from hospitalized patients in 5 different medical centers of the cities of S. Paulo, Rio de Janeiro and Salvador. Our preliminary results with this antibiotic, in final phases of clinical and laboratorial experimentation in this country, are very promissing with, 96.79% of susceptibility of test isolates to 10 mcg imipenem disks and corresponding MIC correlation of up to 4 micrograms/ml. (92.31%). Of the 9 bacterial species more frequently isolated totaling 1108 (82%) of the 1230 test isolates, disk susceptibility was 99% (E. coli), 93% (Pseudomonas aeruginosas), 87% (Staphylococcus aureus), 100% (Klebsiella pneumoniae), 98% (Klebsiella sp), 97% (Proteus mirabiles), 94% (Enterobacter sp), 100% (Streptococcus faecalis) with good MIC correlation (up to 8 mcg/ml) and 100% for the anaerobic species Bacteroides sp (MIC up to 4 micrograms/ml). "In vitro" efficacy to hospital pathogens with high frequency of resistance to most antibiotics as Pseudomonas aeruginosa and to anaerobes notably Bacteroides sp is emphasized.

Campylobacter fetus endocarditis on a prosthetic heart valve

Campylobacter fetus infection in man is rare. Few cases of Campylobacter endocarditis have been described, and none have been associated with a prosthetic heart valve. We have reported a case of Campylobacter fetus ssp fetus on a prosthetic mitral valve in a 48-year-old woman who was treated successfully with penicillin and streptomycin (and later with gentamicin). Replacement of the prosthetic valve was done because of stenosis and vegetations. Pathologic examination showed vegetations on a calcified prosthesis, but no bacteria were seen.

Rapid, automated identification of novobiocin-resistant, coagulase-negative staphylococci

A modified automated method that uses the MS-2 system (Abbott Laboratories, Diagnostics Div., Irving, Tex.) to verify the reaction of coagulase-negative staphylococci to novobiocin is described. This technique permits the testing of a great number of specimens in an average time of 99 min and results in a 100% match with the traditional method of culturing.