Issam Raad

Quantitative tip culture methods and the diagnosis of central venous catheter-related infections☆

The diagnostic usefulness of two quantitative catheter culture methods was compared in a prospective study of central venous arterial catheters. The roll-plate method followed by sonication was used to culture 177 catheters from 85 patients, and the sonication method was used to culture 136 catheters from 68 patients. All patients were evaluated for catheter-related infections. Catheter-related infections were associated with greater than or equal to 100 colony-forming units (CFU) isolated from catheter tips by either roll plate (p = 0.01) or sonication (p less than 0.001). The sensitivity, specificity, and positive and negative predictive values of greater than or equal to 10(3) CFU by roll plate for catheter-related septicemia were 56%, 97%, 63%, and 96% compared with 93%, 95%, 76%, and 99%, respectively, for the same level by sonication. For central venous and arterial catheters, the sonication method can distinguish infection from contamination and is superior to the roll-plate method in that it may offer a more sensitive and predictive alternative in the diagnosis of catheter-related septicemia.

Central Venous Catheter Related Infections: The Role of Antimicrobial Catheters

Intravascular devices are indispensable in modern-day medical practice, especially in the care of critically and chronically ill patients, such as patients in intensive care units (ICU), cancer patients, patients with renal failure requiring chronic hemodialysis, or patients requiring organ or bone marrow transplantation. Additionally surgical patients especially the ones with short bowel syndrome, totally depend on intravenous catheters for their nutritional support. These devices are used to administer intravenous fluids, medications, blood products and total parenteral nutrition (TPN) fluids, as well as for hemodynamic status monitoring of critically ill patients.

Trifluorothymidine: potential non-invasive diagnosis of herpes simplex infection using 19F nuclear magnetic resonance in a murine hepatitis model

n Abstractn n Trifluorothymidine (TFT) is known to be concentrated in herpes simplex virus (HSV) infected cells in vitro in the form of phosphorylated derivatives. We studied a murine hepatitis model of HSV infection to determine whether this in vitro observation would also be demonstrable in vivo. Following i.v. injection of 100 or 160 mg/kg TFT, TFT was found in significantly higher concentrations in the livers of HSV-2 infected mice than in the livers of uninfected mice, mice infected with murine hepatitis virus (MHV-A59) or mice with hepatitis from carbon tetrachloride treatment. Neither altered renal function, nor altered pharmacokinetics could account for this difference. 19F Nuclear Magnetic Resonance spectroscopy readily detected the 19F from TFT in both liver extracts and whole livers, particularly at higher tissue levels, i.e. > 50 μg/g tissue. If further studies with living animals support these preliminary observations, clinical application could be pursued.n n

Infection of the salivary and lacrimal glands

Sialadenitis is infection of the salivary glands. This is a relatively common disease. Sialadenitis can be acute, subacute, or chronic in nature and can be of bacterial or viral origin. Bacterial infections may reach the salivary gland tissue mostly via the ductal system, whereas viral infections invade the salivary glands via the bloodstream. The incidence of bacterial sialadenitis is in direct relation to factors such as old age, nutritional and health status, trauma, anatomic abnormalities, and use of drugs that decrease the salivary flow. There are several etiological predisposing local and systemic generalized factors that play an important role in the development and course of sialadenitis (Table 9.1). ACUTE BACTERIAL SIALADENITIS Acute bacterial sialadenitis is also known as suppurative sialadenitis and mainly affects the parotid and submandibular glands. Sialadenitis of the intraoral and sublingual glands is very rare. This may be due to the fact that the serous saliva produced by the parotid gland has less bacteriostatic activity or may result from a secretory disorder that changes the amount and chemical composition of saliva, including most of the protein, mucins, and electrolytes. Primary acute bacterial parotitis (ABP) has been reported mainly in elderly patients suffering from dehydration, malnutrition, Sjogrens disease, poor oral hygiene, ductal obstructions due to sialolithiasis, tumor or foreign bodies, chronic tonsillitis, dental infection, neoplasm of the oral cavity, liver cirrhosis, or diabetes mellitus.

The Performance of Quantitative Real-Time Polymerase Chain Reaction and Galactomannan for Invasive Fungal Infections in Patients with Hematologic Malignancies

Background: Non-invasive methods to diagnose invasive fungal infections are needed to improve the poor outcome of these infections. We conducted this study to evaluate the diagnostic values of quantitative real time polymerase chain reaction and galactomannan in hematological malignancy patients. nResults: Eighty-two consecutive patients with cancer were identified and prospectively followed for three nmonths. Molecular testing using a quantitative polymerase chain reaction assay amplifying two primers 5.8S and 18S rRNA fungal genes and galactomannan was performed on 1540 blood samples and correlated with clinical data. Amplification of the 5.8S rRNA fungal gene had significantly higher sensitivity than amplification of the 18S rRNA gene for samples from either source (for blood samples: 90% vs 50%, p=0.007; for serum samples: 64% vs 5%, p<0.001). nConclusions: Galactomannan when used alone had a sensitivity of 38% and a specificity of 100%. The nsensitivity of the combination assay of quantitative polymerase chain reaction plus galactomannan was significantly higher than that of GM test alone (71% vs 38%, p=0.03). Detection of the 5.8S rRNA fungal gene had significantly higher sensitivity than the 18S rRNA gene for samples from either source blood or serum. The combination of quantitative polymerase chain reaction plus galactomannan assay improved the diagnostic value of invasive fungal infections.