Escherichia coli tetracycline efflux determinants in relation to tetracycline residues in chicken

ObjectiveTo screen for Escherichia coli (E. coli) resistant to tetracycline, followed by identification of tet efflux genes by polymerase chain reaction (PCR). In addition, detection of tetracycline residues in chicken livers and kidneys were conducted using high performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS).MethodsStrains of E. coli were isolated from samples of chicken colon and screened for tetracycline resistance. Tetracycline genes conferring resistance (Tc^r) were detected by polymerase chain reaction (PCR). Most of the isolates were resistant to tetracycline (97.9%).ResultsPCR analysis indicated that Tc^r E. coli R-plasmids contained tet(A), tet(B) and a combination of both efflux genes. None of the isolates contained other efflux tet genes tet (C, D, E and Y). High performance liquid chromatography-tandem quadrupole mass spectrometry (HPLC-MS-MS), a sensitive technique, was used to detect residues of chlortetracycline (CTC), oxytetracycline (OTC), doxycycline (DC) in chicken livers and kidneys. The samples containing tetracycline residues were at 0.13-0.65 pg/μL levels.ConclusionsTetracycline and other antibiotics are commonly used in the poultry and meat production industry for prevention of microbial infections. Multiple antibiotic resistant bacteria in Oman have increased to alarming levels, threatening public health, domestic and may have adverse effect on environment.     

Can one stop nucleic acid sampling (OSNA) predict nodal positivity following neoadjuvant chemotherapy? A prospective cohort study of 293 patients

Until recently, axillary node clearance had long been the standard of care in patients with axillary node-positive disease. One stop nucleic acid sampling (OSNA) has been used to guide intraoperative decision-making regarding suitability for axillary node clearance (ANC). The aim of this study is to evaluate the use of OSNA following neoadjuvant chemotherapy (NACT) and whether it can predict lymph node burden in ANC. A single center, prospective cohort study was performed on 297 patients having OSNA between 2016 and 2019. Patients were sub-classified according to node positivity at diagnosis and those treated with NACT and outcomes included copy number and lymph node harvest. Axillary complete pathological response was observed in 24/36 patients (67%) following NACT. 14/16 patients (87%) having axillary node clearance had axillary node disease limited to 4 nodes. OSNA copy numbers were significantly higher in patients showing disease progression following NACT. Overall, 73% of patients with lymph node positivity at diagnosis could be successfully treated with a combination of NACT and lymph node excision of four nodes. De-escalating axillary surgical treatment to resection of four nodes following NACT may be effective in balancing oncological resection and limiting treatment morbidity. ONSA can correctly identify patients experiencing disease progression who would benefit from traditional three-level ANC.     

A Correlation of the Platelet Count with D-Dimer Levels as an Indicator for Component Therapy in Children with Dengue Hemorrhagic Fever

Dengue Fever (DF) may evolve into two life threatening forms—Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS). DHF is associated with increased vascular permeability and plasma leakage causing thrombocytopenia and loss of clotting factors into the third space and may result in bleeding initially due to thrombocytopenia and later due to disseminated intravascular coagulation (DIC), often as a terminal event. Prompt recognition and treatment of minor bleeds in DF children with incipient DIC with component therapy may be associated with improved survival while failure to do so is usually catastrophic. A sensitive marker for early DIC is the presence of D-dimer (DD) in the blood. To determine the correlation between the severity of thrombocytopenia and early DIC in children with DHF. The impact of additional factors like age and shock will also be evaluated. Case control prospective study of 60 DHF sero -positive children (1–15 years) with thrombocytopenia. After clinical evaluation they were divided into two equal groups based on the degree of thrombocytopenia (more than/less than 30,000/mm³). PT/APTT and DD levels were estimated in all children of both groups and statistical correlation was done. There was no significant difference in the DD levels between the two groups. However, children in either group, presenting with clinical features of shock and thrombocytopenia had significantly higher DD levels. Empirical component therapy in children with DHF based purely on their low platelet counts may not be justified. However, in DHF children with thrombocytopenia and features of shock, aggressive component therapy may prevent subsequent bleeding and may be justified.