Analysis of Salmonella spp. with resistance to extended-spectrum cephalosporins and fluoroquinolones isolated in North America and Latin America: report from the SENTRY Antimicrobial Surveillance Program (1997-2004)

Emerging antimicrobial-resistant Salmonella spp. requires increased efforts to appropriately test susceptibility. The SENTRY Antimicrobial Surveillance Program monitored Salmonella spp. and detected nalidixic acid-resistant strains with elevated fluoroquinolone minimum inhibitory concentration (MIC) results and strains with extended-spectrum beta-lactamase (ESBL) "phenotypes" over the last 8 years. A total of 786 stool and bloodstream isolates from North American and Latin American medical centers (2001-2003) were tested by reference broth microdilution methods. Genetic analysis was used to further characterize the resistance mechanisms. Twenty-one sites forwarded 89 (11.3%) nalidixic acid-resistant (MIC, > or =32 microg/mL) strains. Nineteen of these isolates were studied to determine mutations in the quinolone resistance-determining region (QRDR). Among the nalidixic acid-resistant Salmonella spp. isolates, fluoroquinolone MIC values were also elevated (8- to 32-fold) compared with "wild-type" strains. Ciprofloxacin and gatifloxacin (MIC(90), 0.5 microg/mL) were more potent than levofloxacin and garenoxacin (1 microg/mL) against nalidixic acid-resistant strains. Single gyrA mutations were responsible for elevated fluoroquinolone MIC values and included D87Y (5), S83F (7), D87N (5), and S83Y (2). During 2001, 9 sites contributed 11 (2.9%) strains that met ESBL screening criteria (> or =2 microg/mL) for aztreonam or ceftazidime or ceftriaxone. ESBL confirmation was evaluated by Etest (AB BIODISK, Solna, Sweden) ESBL strips and the enzymes were characterized by polymerase chain reaction and gene sequencing. The ESBL phenotype isolates had the following MIC patterns: ceftazidime (> or =16 microg/mL), aztreonam (4 to >16 microg/mL), and ceftriaxone (8-32 microg/mL). All strains were susceptible to cefepime, carbapenems, gentamicin, and fluoroquinolones. No strains were inhibited by clavulanic acid consistent with all isolates producing the identified CMY-2, AmpC-like enzyme. Fluoroquinolones may be compromised among isolates with QRDR mutations detected using nalidixic acid as a screening agent. Salmonella spp. with ESBL phenotypes were likely to harbor CMY-2 (not an ESBL) and remain susceptible to cefepime, carbapenems, and fluoroquinolones, which can be used for serious invasive Salmonella spp. infections. Compared with the stool culture isolates, the blood culture isolates had higher QRDR mutations, but remained susceptible to the fluoroquinolones. The blood culture isolates were more susceptible to penicillins (ampicillin and ticarcillin) and not significantly different for ceftriaxone or trimethoprim/sulfamethoxazole susceptibility patterns. No QRDR trends over time were detected in North America, but increased resistance was observed in Latin America.     

Accurate estimates of absolute left ventricular volumes from equilibrium radionuclide angiographic count data using a simple geometric attenuation correction

To simplify and clarify the methods of obtaining attenuation-corrected equilibrium radionuclide angiographic estimates of absolute left ventricular volumes, 27 patients who also had biplane contrast cineangiography were evaluated. Background-corrected left ventricular end-diastolic and end-systolic counts were obtained by semiautomated variable and hand-drawn regions of interest and were normalized to cardiac cycles processed, frame rate and blood sample counts. Blood sample counts were acquired on (d degree) and at a distance (d') from the collimator. A simple geometric attenuation correction was performed to obtain absolute left ventricular volume estimates. Using blood sample counts obtained at d degree or d', the attentuation-corrected radionuclide left ventricular end-diastolic volume estimates using both region of interest selection methods correlated with the cineangiographic end-diastolic volumes (r = 0.95 to 0.96). However, both mean radionuclide semiautomated variable left ventricular end-diastolic volumes (179 +/- 100 [+/- 1 standard deviation] and 185 +/- 102 ml, p less than 0.001) were smaller than the average cineangiographic end-diastolic volume (217 +/- 102 ml), and both mean hand-drawn left ventricular end-diastolic volumes (212 +/- 104 and 220 +/- 106 ml) did not differ from the average cineangiographic end-diastolic volume. Using the blood sample counts obtained at d degree or d', the attenuation-corrected radionuclide left ventricular end-systolic volume estimates using both region of interest selection methods correlated with the cineangiographic end-systolic volumes (r = 0.96 to 0.98). Also, using blood sample counts at d degree, the mean radionuclide semiautomated variable left ventricular end-systolic volume (116 +/- 98 ml, p less than 0.05) was less than the average cineangiographic end-systolic volume (128 +/- 98 ml), and the other radionuclide end-systolic volumes did not differ from the average cineangiographic end-systolic volume. Therefore, it is concluded that: 1) a simple geometric attenuation-correction of radionuclide left ventricular end-diastolic and end-systolic count data provides accurate estimates of biplane cineangiographic end-diastolic and end-systolic volumes; and 2) the hand-drawn region of interest selection method, unlike the semiautomated variable method that underestimates end-diastolic and end-systolic volumes, provides more accurate estimates of biplane cineangiographic left ventricular volumes irrespective of the distance blood sample counts are acquired from the collimator.     

Altered myosin light-chain phosphorylation in resting platelets from premenopausal women with diabetes

Gender-related differences in the rate of coronary heart disease (CHD) between premenopausal women and men are greatly diminished in women with diabetes mellitus (DM). This may be related, in part, to altered platelet function in premenopausal diabetic women. Hyperglycemia may contribute to increase platelet aggregation through enhancement of oxidative stress, increased nitric oxide (NO) destruction, and increased myosin light-chain (MLC) phosphorylation (MLC-P). Accordingly, we investigated functional and biochemical parameters of platelet function in 32 women (14 premenopausal and postmenopausal controls and 18 age-matched patients with DM); platelet MLC-P and cyclic guanosine monophosphate ([cGMP] reflecting NO) were assessed. Other parameters including age, body mass index (BMI), waist to hip ratio, total cholesterol, and platelet count were not different in the control and diabetic groups. In the premenopausal women, baseline MLC-P was lower in women with DM versus the control group (P = .02). GMP levels were similar in the two groups at baseline (22.7 +/- 3 fmol/mL in controls v 23.1 +/- 3 fmol/mL in diabetic subjects) and 3 minutes after insulin exposure. The platelet content of ascorbic acid (AA), an endogenous antioxidant compound, was elevated in premenopausal women with DM (P = .02) compared with the controls. Despite similar estradiol (beta,E2) levels, platelets of premenopausal women with DM exhibited reduced MLC-P. This paradoxic difference may be accounted for by an increase in platelet AA, as this suggests decreased platelet oxidative stress in this patient population. These observations indicate that an altered redox state and associated MLC-P of platelets does not contribute to enhanced platelet aggregation and CHD in premenopausal women with DM.     

Multiple analysis of three common genetic alterations associated with thrombophilia.

We have previously reported the use of a novel mini-sequencing protocol for detection of the factor V Leiden variant, the first nucleotide change (FNC) technology. This technology is based on a single nucleotide extension of a primer, which is hybridized immediately adjacent to the site of mutation. The extended nucleotide that carries a reporter molecule (fluorescein) has the power to discriminate the genotype at the site of mutation. More recently, the prothrombin 20210 and thermolabile methylene tetrahydrofolate reductase (MTHFR) 677 variants have been identified as possible risk factors associated with thrombophilia. This study describes the use of the FNC technology in a combined assay to detect factor V, prothrombin and MTHFR variants in a population of Australian blood donors, and describes the objective numerical methodology used to determine genotype cut-off values for each genetic variation. Using FNC to test 500 normal blood donors, the incidence of Factor V Leiden was 3.6% (all heterozygous), that of prothrombin 20210 was 2.8% (all heterozygous) and that of MTHFR was 10% (homozygous). The combined FNC technology offers a simple, rapid, automatable DNA-based test for the detection of these three important mutations that are associated with familial thrombophilia.     

Immunocytochemical localization of a granuliberin-like peptide in Rana pipiens brain

The histamine-releasing peptide “granuliberin”, originally isolated from the skin of Rana rugosa, was localized by immunofluorescence within nerve cell bodies and fibers in the brain of Rana pipiens. The granuliberin-positive neurons were characterized ultrastructurally by electron microscopic observation of ultrathin sections stained either with immunoperoxidase or with conventional stains. Granuliberin-positive nerve cell bodies were seen throughout the hypothalamus, from the suprachiasmatic area rostrally to the full length of the periinfundibular grey matter caudally. Similarly positive nerve fibers were localized in the hypothalamus radiating upwards to the optic vesicles in the midbrain, extending through the preoptic area into the subpallium in the forebrain, and throughout the white matter surrounding the floor and lateral walls of the fourth ventricle in the brainstem. The granuliberin-positive nerve cells showed the presence of variable numbers of small cytoplasmic neurosecretory granules. Possessing an electron dense elongated core, and measuring 250–350 nm in their largest diameter. The functional significance of a granuliberin-like peptide in neurons of the frog brain is not known.     

Is the presence of an uncleaved embryo on day 3 a useful predictor of outcomes following day 5 transfer?

Purpose

This study aimed to determine whether the presence of an uncleaved embryo on day 3 is predictive of cycle outcome after day 5 transfer (D5 ET).

Methods

In vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles from January 2013 to November 2014 with D5 ET were analyzed for the presence of at least one uncleaved embryo on day 3 (D3). Each index cycle (n = 70) was compared with two matched control cycles without uncleaved embryos. The main outcome measures included embryo quality, implantation rate, and clinical pregnancy rate.

Results

Fifty-nine of 3896 total embryos in this study were uncleaved on D3 (1.5 %). Cycles with uncleaved embryos had more oocytes retrieved (20.6 vs. 17.5), lower proportions of good quality embryos on D3 (52.4 vs. 66.1 %), and fewer usable embryos (transferred or frozen) on D5 (42.4 vs. 50.8 %). However, there were no significant differences in the incidence of cycles with a positive hCG, or in the rates of implantation, clinical pregnancy, or live birth.

Conclusions

Although an uncleaved embryo on D3 is associated with reduced conversion of sibling embryos to the blastocyst stage on D5, overall quality of those embryos forming blastocysts is not markedly decreased and clinical outcomes are not compromised.     

Meconium stained fluid: approach to the mother and the baby

Meconium aspiration syndrome (MAS) is a common problem that most pediatricians will encounter in the delivery room and normal newborn nursery. Approximately 13% of all live births are complicated by meconium stained amniotic fluid (MSAF). MAS is defined as respiratory distress in an infant born through MSAF whose symptoms cannot be otherwise explained. Optimal care for an infant born through MSAF involves cooperation between the obstetrician and pediatrician, each with separate but imperative roles.     

Rupture of the primigravid uterus: a review of the literature

Uterine rupture is a catastrophic obstetric complication, associated with high rates of perinatal morbidity and mortality. The most common risk factor is previous uterine surgery, and most cases of uterine rupture occur in women with a previous cesarean delivery. Traditionally, the primigravid uterus has been considered almost immune to spontaneous rupture. In fact, although spontaneous rupture of the primigravid uterus is indeed a very rare event, a number of such cases have been reported recently. Prompt recognition of uterine rupture and expeditious recourse to laparotomy are critical in influencing perinatal and maternal morbidity. Not all uterine ruptures present with the typical clinical picture of abdominal pain, hypovolemia, vaginal bleeding, and fetal compromise. Therefore, it is important to maintain a high index of suspicion for uterine rupture in women presenting with some, or all, of these features, regardless of parity. Here we provide a systematic review of cases of spontaneous uterine rupture in primigravid women reported in the literature to date. Clinical presentation, differential diagnosis, common etiological factors, complication rates, and appropriate management of this rare obstetric event are discussed. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to recall that uterine rupture in a primigravida is a rare event, without typical signs and symptoms, and explain that the morbidity and mortality of the mother and child is directly related to a high index of suspicion and prompt treatment by the clinician.