Aminoglycosides are often used to treat severe infections with gram-positive organisms. Previous studies have shown concentration-dependent killing by aminoglycosides of gram-negative bacteria, but limited data are available for gram-positive bacteria. We compared the in vitro pharmacodynamics of gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa. Five S. aureus strains were examined (ATCC 29213 and four clinical isolates). Time-kill studies (TKS) in duplicate (baseline inocula of 107 CFU/ml) were conducted to evaluate bacterial killing in relation to increasing gentamicin concentrations (0 to 16 times the MIC). Serial samples were obtained over 24 h to quantify bacterial burden. Similar TKS with P. aeruginosa ATCC 27853 were conducted, and the time courses of the all bacterial strains were mathematically modeled for quantitative comparison. A dose fractionation study (using identical daily doses of gentamicin) in an in vitro hollow-fiber infection model (HFIM) over 5 days was subsequently used for data validation for the two ATCC strains. Model fits to the data were satisfactory; r2 values for the S. aureus and P. aeruginosa ATCC strains were 0.915 and 0.956, respectively. Gentamicin was found to have a partially concentration-dependent killing effect against S. aureus; concentrations beyond four to 8 times the MIC did not result in significantly faster bacterial killing. In contrast, a concentration-dependent profile was demonstrated in suppressing P. aeruginosa regrowth after initial decline in bacterial burden. In HFIM, thrice-daily gentamicin dosing appeared to be superior to once-daily dosing for S. aureus, but they were similar for P. aeruginosa. Different killing profiles of gentamicin were demonstrated against S. aureus and P. aeruginosa. These results may guide optimal dosing strategies of gentamicin in S. aureus infections and warrant further investigations.

Comparative Pharmacodynamics of Gentamicin against Staphylococcus aureus and Pseudomonas aeruginosa

This article presents the main problems derived from the mammary infections (mastitis) caused by Staphylococcus aureus, and the consequences of the presence of its toxins in milk for human health. S. aureus is one of the most important microorganisms that can be transmitted through the food products. Hence, the possibility of transmission of stafilococal gastroenteritis by consumption of raw milk and heat-treated milk, containing heat-resistant enterotoxins, is discussed. Some aspects regarding the toxigenic potential of S. aureus strains and the main characteristics of stafilococal entorotoxins are presented. Taking into account that S. aureus is also one of the most prevalent agents of mastitis, considerations are made on the methods for the controlling of stafilococal infections in dairy cattle, in order to prevent the occurrence of toxins in milk and milk products.

/pdf/infeccoes-intramamarias-causadas-por-staphylococcus-aureus-e-vphmft5msv.pdf

Infecções intramamárias causadas por Staphylococcus aureus e suas implicações em paúde pública

Escherichia coli O157:H7 is recognized as a significant food-borne pathogen, so rapid identification is important for food hygiene management and prompt epidemiological investigations. The limited prevalence data on Shiga toxin-producing E. coli (STEC) and E. coli O157:H7 in foods and animals in Korea made an assessment of the risks difficult, and the options for management and control unclear. The prevalence of the organisms was examined by newly developed kit-E. coli O157:H7 Rapid kit. For the isolation of E. coli O157:H7, conventional culture, immunomagnetic separation, and E. coli O157:H7 Rapid kit were applied, and multiplex PCR and randomly amplified polymorphic DNA (RAPD) were performed for the molecular determination. There was high molecular relatedness among 11 Korean isolates and 17 U.S. strains at 63% level. Additionally, distinct differentiation between pig and cattle isolates was determined. It implied that RAPD had a capacity to distinguish strains with different sources, however it could not discriminate among isolates according to their differences in the degree of virulence. In antimicrobial susceptibility tests, 45.5% of isolates showed antibiotic resistance to two or more antibiotics. Unlike the isolates from other countries, domestic isolates of E. coli O157:H7 was mainly resistant to ampicillin and tetracyclines. In summary, the application of E. coli O157:H7 Rapid kit may be useful to detect E. coli O157:H7 due to its sensitivity and convenience. Moreover, combinational analysis of multiplex PCR together with RAPD can aid to survey the characteristics of isolates.

/pdf/isolation-and-identification-of-escherichia-coli-o157-h7-58x5yacf6q.pdf

Isolation and identification of Escherichia coli O157:H7 using different detection methods and molecular determination by multiplex PCR and RAPD.

Staphylococcus aureus is a known major cause of foodborne illnesses, and milk and dairy products are often contaminated by enterotoxigenic strains of this bacterium. In the present study, 122 S. aureus isolates collected from different dairy products were characterised by phenotypic properties, by the distribution of genes encoding staphylococcal enterotoxins (sea, sec, sed, seg, seh, sei, sej, and sel) and by randomly amplified polymorphic DNA PCR (RAPD-PCR). Moreover, strain resistance to vancomycin and methicillin (oxacillin) was studied. The differences in the RAPD-PCR profiles obtained with the primers M13 and AP4 revealed the presence of a great genetic heterogeneity among the different S. aureus strains. Using the primer AP4 and M13, eight groups were distinguished by RAPD-PCR cluster analysis, although, except in few cases, it was not possible to correlate the isolates of different animal species (cow or ovine) with the presence of se genes. None of the isolates showed resistance to vancomycin or methicillin.

/pdf/phenotypic-and-genotypic-characterization-of-staphylococcus-418kq3axsc.pdf

Phenotypic and Genotypic Characterization of Staphylococcus aureus Strains from Italian Dairy Products

Aims: To evaluate the utility of random amplification of polymorphic DNA (RAPD) technique for routine practice in public health laboratories for epidemiological studies of Vibrio cholerae O1 isolates.



Materials and Results:  Seventy-nine strains were examined by PCR for the toxin genes (ctx A, zot and ace), virulence-associated genes (tcp A and tox T) and RAPD sequences. Except for one strain (no. 1123) from the Amazonas State, all the strains analysed carried the genes ctx A, zot, ace, tcp A and tox T. RAPD fingerprinting revealed variability but no correlation with serotype, biotype or geographical origin of the isolates was found.



Conclusion:  A standardized RAPD method does not enable the establishment of a pattern data bank for the identification of V. cholerae O1 strains.



Significance and Impact of the Study:  The simplicity and discriminative capacity of this technique make it useful for detecting genetic diversity among micro-organisms from a defined group or for outbreak investigation.

https://sfamjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2004.02090.x

Evaluation of a RAPD-based typing scheme in a molecular epidemiology study of Vibrio cholerae O1, Brazil.

Aims:  To investigate genetic diversity among Staphylococcus aureus and to delineate the geographical distribution of the strains found.



Methods and Results:  RAPD-PCR and ribotyping-PCR were employed for the characterization of Staph. aureus isolates from bovine and nosocomial origin. Among the strains, five to nine groups were distinguished by RAPD-PCR, depending on which primer was used, while ribotyping-PCR distinguished seven ribotypes.



Conclusions, and Significance and Impact of the Study:  These results demonstrate the genetic heterogeneity of the strains studied, and the large dissemination of some clones throughout different regions and hosts, findings that may allow the monitoring of Staph. aureus infections.

https://sfamjournals.onlinelibrary.wiley.com/doi/pdf/10.1046/j.1472-765X.2002.01127.x

Typing of human and bovine staphylococcus aureus by rapd-pcr and ribotyping-pcr

Introduction Spinal cord infarction (SCI) in children is rare and difficult to diagnose. Fibrocartilaginous embolism (FCE) is probably the underlying cause for some unexplained cases of spinal cord infarcts. Abrupt back pain followed by a progressive syndrome of myelopathy appears to be the typical presentation, with a close temporal relationship between the onset of symptoms and preceding minor trauma. Supportive care and rehabilitation are essential in the treatment of children with SCI. Case report A previously healthy 12-year-old girl who practiced acrobatic gymnastics was admitted to a rehabilitation centre 14 days after being diagnosed with an acute anterior SCI with no identified cause. Sensory modality of pin prick and light touch were impaired, with the former more significantly affected. She was not able to run and had difficulty on monopodal standing and performing motor sequencing. Additionally, she mentioned ineffective cough along with flatus incontinence and normal bladder function. After a 4-week multidisciplinary rehabilitation program her neurologic deficits improved. Discussion Given the patient's age and clinical presentation, a literature review led to the consideration of FCE as the most likely definitive diagnosis. It should be recognized as a cause of SCI especially in those involved in sport activities, even if previous trauma is denied.

Spinal cord infarction in children: Can gymnastics be a cause?

Chorea is a hyperkinetic movement disorder characterised by brief involuntary, random, and irregular contractions. It’s caused by multiple conditions, including neurodegenerative diseases, cerebrovascular disease, structural damage to deep brain structures, neoplastic diseases, or metabolic derangements, such as hyperglycaemic states. 
We present a case of an 81-year-old woman, with a history of long-term poorly controlled type 2 diabetes mellitus, admitted to the emergency department with hyperkinetic delirium in the last 48h. At examination, she presented with mild right central facial paresis, and involuntary bilateral movement of the four limbs, more prominent on the right side. Laboratory tests showed hyperglycaemia of 799 mg/dl with ketonemia of 5.2 mg/dL and glycated hemoglobin of 11%. Computed tomography (CT) scan of the brain showed bilateral hyperdensity of the corpus striatum. The treatments included glycemic control with insulin, intravenous fluids, and anti-epileptic drugs. A clinical improvement was observed however, the patient continued to show chorea-like movements of the four limbs. The magnetic resonance imaging (MRI) showed a T2-flair and T2-weighted area of hypo-intensity involving bilaterally the striatum corpus and the corresponding signal in T1. She was then diagnosed with hyperglycaemia-associated chorea and improved significantly after initiation and titration of clonazepam and tetrabenazine.
This case report pretends to highlight the importance of considering a rare manifestation of a very common disease. A hyperglycaemic state that can lead to cerebral lesions and specific neurological manifestations.

Chorea as a rare neurological complication of hyperglycaemia

The May–Thurner Syndrome (MTS) is a rare anatomical condition in which the compression of the left common iliac vein by the right common iliac artery causes an outflow obstruction, presenting frequently as chronic venous insufficiency or deep venous thrombosis (DVT). This variant is rarely considered when investigating DVT, especially in patients with other risk factors. MTS requires careful workup and management to avoid complications such as chronic venous insufficiency, post-thrombotic syndrome, and primary lymphedema. 
The authors present a 63-year-old woman admitted to the emergency department with a 24-hour history of left lower limb pain and edema. Initial assessment, with computed tomography of the lower left limb and pelvis, showed compression of the left common iliac vein with an extensive thrombus of the left common iliac and external iliac veins, as well as femoral and popliteal left veins, consistent with MTS. Therapeutic enoxaparin initially implemented, was then switched to oral anticoagulation. At 6 months reevaluation, venous duplex ultrasound showed only partial recanalization of the femoral vein. 
Investigation for May-Thurner Syndrome in patients with left lower limb venous thrombotic events, regardless of risk factors, should always be present since the establishment of an effective therapeutic plan and eventually, endovascular treatment can minimize the long-term sequelae of deep vein thrombosis.

Margarida Pereira

Papers

Typing of human and bovine staphylococcus aureus by rapd-pcr and ribotyping-pcr

Spinal cord infarction in children: Can gymnastics be a cause?

Chorea as a rare neurological complication of hyperglycaemia

May-Thurner Syndrome: a case of unilateral left lower limb deep vein thrombosis