Electron microscopic assay of bacterial biofilm formed on indwelling urethral catheters

Biofilm formation on indwelling urinary catheters is a leading cause of Urinary tract infection [UTI]. Presence of biofilm is associated with increased bacterial resistance to antimicrobial therapy and resultant treatment failure. The study detected a reliable method for diagnosis of biofilm formation by comparing scanning electron microscopy [SEM] and tissue culture plate method [TCP]. The work was conducted on 20 urinary catheters from patients ranging from 1.5 to 85 years with catheters that remained in situ for a period of 3 to 20 days. Samples of catheters for culture and SEM and samples of urine were taken at the same time. The correlation between renal conditions and biofilm formation was not significant [p=0.336]. No significant correlation [p =0.836, 0.163 respectively] was found between predisposing conditions [DM, renal insufficiency, diarrhea and impaired immunity] and development of Catheter associated urinary tract infection [CAUTI] and biofilm formation. Biofilm formation increased with duration of catheter in situ, but no significant correlation was found [p=0,095]. This could be due to small number of specimens. 9/20[45%] urine samples, 12/20[60%] catheter samples were positive by culture and 14/20[70%] catheters showed biofilm on SEM. 4/12[33.33%] organisms isolated from catheter culture produced biofilm by TCP method. 9 isolates were recovered from 9 positive urine cultures. The microorganisms isolated were non Candida albicans [3/9], E. coli [2/9], C. albicans [2/9] and Acenitobacter [2/9]. 14 isolates were recovered from 12 culture positive catheters. The organisms isolated were E. coli [3/14], non-Candida albicans [3/14], C. albicans [2/14], C tropicalis [2/14], Acenitobacter [2/14], Klebsiella [1/14] and Enterococcus [1/14]. Reduction in microbial diversity with antimicrobial use was noticed but the correlation was insignificant [p=0.317]. The correlation between urine culture results as well as catheter culture results and biofilm formation by SEM were both significant [p 0.008 and 0.000 respectively]. The correlation between urine culture and TCP assay was insignificant [p=237]. Using SEM as the gold standard method for the detection of biofilm, the sensitivity, specificity, total accuracy, PPV and NPV of urine culture and catheter culture were, 64.30%, 100%, 75%, 100%, 54% and 85.70%, 100%, 90%,100%,.75% respectively

Assessment of possible pulmonary involvement in patients with rheumatoid arthritis [RA] under methotrexate [MTX] therapy: comparison of clinical, functional, histopathological, high resolution computed tomography [HRCT] and laboratory features capability to detect pulmonary changes

Lung involvement in systemic disease may be a manifestation of the underlying pathological process, may be complication of the underlying disease or may be related to the treatment. Methotrexate [MTX], a folic acid antagonist is widely used in rheumatoid arthritis treatment; however, methotrexate-induced pulmonary drug toxicity occurs in 27% of patients. Difficulty in diagnosing these lesions had led-many researchers to assess the capability of every possible investigation [radiologic, functional, histopathologic, even 99mTc-DTPA scan] in reaching early diagnosis and differentiating it from those led by the original disease or that caused by infection, as early diagnosis and management carries good prognosis to an apparently fatal disease. Thus we compared in this study different diagnostic methods for detection of lung involvement due to MTX. We were able to detect pulmonary affection in some studies cases radiological and histopathologically, however, clinical and functional investigations lagged behind in their capabilieate the lung involvement.