Distribution of Ambler class A, B and D β-lactamases among Pseudomonas aeruginosa isolates

Objectives

We determined the prevalence rate of classes A, B and D β-lactamases among extended-spectrum cephalosporin (ESC)-non-susceptible Pseudomonas aeruginosa clinical isolates from burned patients.

Methods

Disc susceptibility testing was performed on 156 P. aeruginosa isolates collected during 2010 at Prince Salman Hospital in Riyadh, Saudi Arabia. Phenotypic screening of ESBLs and MBLs in the isolates resistant to ceftazidime (MIC > 8 mg/L) was carried out. Genes encoding ESBLs and MBL were sought by PCR in ESBL- and MBL-producing isolates.

Results

The resistance rate to ceftazidime was 22.43%. The resistance rates for ESC-non-susceptible P. aeruginosa isolates to piperacillin, piperacillin/tazobactam, cefepime, aztreonam, imipenem, amikacin, gentamicin and ciprofloxacin were 100%, 71.14%, 88.57%, 48.57%, 70.0%, 82.5%, 87.5%, and 90.0% respectively. No resistance was detected to polymyxine B. The prevalence of ESBL and MBL in ESC-non-susceptible P. aeruginosa was 69.44% and 42.85%, respectively. The prevalence of structural genes for VEB-1, OXA-10 and GES ESBLs in P. aeruginosa was 68%, 56% and 20%, respectively. VIM gene was detected in 15 (100%) of MBL-producing isolates. OXA-10 like gene was concomitant with VEB, GES and/or VIM. Eight isolates harbored OXA-10 with VEB (imipenem MIC 6–8 mg/L), while five isolates harbored OXA-10 with VIM (imipenem MIC ≥ 32 mg/L) and one isolate contained OXA-10, VEB and GES (imipenem MIC 8 mg/L). PER was not detected in this study.

Conclusion

VEB-1 and OXA-10 are the predominant ESBL genes and bla_VIM is the dominate MBL gene in ESC-non-sensitive P. aeruginosa isolates in Saudi Arabia. VEB, OXA-10 and GES ESBLs have not been reported previously in Saudi Arabia and GES has not been reported previously in Middle East and North Africa.     

The fate of acutely inflamed joints with a negative synovial fluid culture

Purpose

The purpose of this study was to evaluate the management and fate of acutely inflamed joints with a negative synovial fluid culture.

Methods

Between January and December 2009, all the patients who presented to our institution with an acutely inflamed joint and were subjected to microbiological assessment of their synovial fluid, were included in the study. Patients with a positive synovial fluid culture, a prosthetic joint replacement in situ and where an aspirate was obtained for a rheumatological diagnosis were excluded. This cohort was then divided into two groups depending on whether a diagnosis could be established through the course of their treatment. Group I included patients in whom a diagnosis could be established and group II included patients in whom a diagnosis could not be established. A thorough review of the patients’ medical records and the hospital database was performed. Following this, a database consisting of the patient demographics, clinical features, investigations, treatment and outcome was created.

Results

A total of 144 patients met the inclusion criteria (group I: 95, group II: 49). The most commonly affected joint in both the groups was the knee. The average time to presentation was shorter in group II. Clinical findings at presentation were comparable in both groups. However, inflammatory markers were more likely to be raised in group II in comparison with group I. Eighty-two percent of group II required antibiotic treatment compared with 15% of group I. The mean duration of antibiotic treatment in group I was ten days and in group II was 26 days. Mean hospital stay differed significantly between the two groups, with group II being more than twice as long as compared with group I (p = 0.001). The rate of mortality was also higher in group II (8.2%, p = 0.03).

Conclusion

Our study shows that patients presenting with an acutely inflamed joint and a negative synovial fluid culture in whom a diagnosis cannot be established during their hospital stay have a longer hospital stay and an increased rate of mortality as compared with patients in whom a diagnosis can be established.     

Rectal imaging: part 1, High-resolution MRI of carcinoma of the rectum at 3 T

OBJECTIVE: MRI is currently the imaging modality of choice for the detection, characterization, and staging of rectal cancer. A variety of examinations have been used for preoperative staging of rectal cancer, including digital rectal examination, endorectal (endoscopic) ultrasound, CT, and MRI. Endoscopic ultrasound is the imaging modality of choice for small and small superficial tumors. MRI is superior to CT for assessing invasion to adjacent organs and structures, especially low tumors that carry a high risk of recurrence. CONCLUSION: High-resolution MRI is an accurate and sensitive imaging method delineating tumoral margins, mesorectal involvement, nodes, and distant metastasis. In this article, we will review the utility of rectal MRI in local staging, preoperative evaluation, and surgical planning. MRI at 3 T can accurately delineate the mesorectal fascia involvement, which is one of the main decision points in planning treatment.     

Hepatoprotective effect of the selective mineralocorticoid receptor antagonist, eplerenone against carbon tetrachloride-induced liver injury in rats

Background. Eplerenone is a selective mineralocorticoid receptor (MR) antagonist, and its potential protective role in cardiovascular injury has been reported by several studies. However, whether and how this drug can ameliorate hepatic injury in rats is unknown.Material and methods. The present study was conducted to investigate effect of eplerenone against liver injury induced by carbon tetrachloride (CCl₄) in rats. The biochemical liver function tests and oxidative stress parameters including malondialdehyde (MDA), reactive oxygen species (ROS), in addition to the reduced glutathione (GSH) levels were evaluated. Moreover, serum tumor necrotic factors (TNF-α) level and histopathological changes were examined.Results. Our results show that pre-treatment with eplerenone (4 mg/kg per day for 4 weeks) revealed attenuation in serum activities of alanine aminotransferase (ALT), aspartate aminotransferase, (AST), alkaline phosphatase (ALP) and bilirubin levels that were enhanced by CCl₄. Further, pre-treatment with eplerenone inhibited the elevated hepatic MDA content and restored hepatic GSH to its normal level. The enhanced hepatic ROS production in CCl₄-treated group was markedly decreased by eplerenone administration. Eple-renone pre-treatment significantly attenuated the inflammatory responses caused by CCl₄ as evident by the decreased serum TNF-α level. Histopathological studies showed that eplerenone alleviated the liver damage and reduced the lesions caused by CCl₄.Conclusion. Collectively, the present study provides a proof to hepatoprotective actions of eplerenone via reducing oxidative stress and inflammatory responses in CCl₄-induced liver damage in rat model.     

Single-centre experience with cyclosporin in 106 children with idiopathic focal segmental glomerulosclerosis.

BACKGROUND: Although remission is achieved in most children with nephrotic syndrome by treatment with corticosteroids, a significant proportion of patients experience relapses. Continuous or repeated use of corticosteroids inevitably induces features of steroid side-effects. Cyclosporin (CsA) has been used in the treatment of idiopathic steroid-dependent and -resistant nephrotic syndrome. However, relapse often occurs shortly after the CsA treatment is terminated. Furthermore, long-term clinical outcome of patients treated with CsA is unclear. METHODS: We retrospectively reviewed the data of 106 nephrotic children having primary focal segmental glomerulosclerosis (FSGS) who received CsA between 1993 and 2002. Indications of CsA therapy were steroid resistance (n = 45) and steroid dependence with steroid toxicity (n = 61). Fifty-four patients received cyclophosphamide prior to CsA therapy. CsA starting dose was 6 mg/kg/day to be readjusted to maintain a whole blood trough level of 80-150 ng/ml. The drug was received for 6-48 months (mean: 22.1+/-11 months). The observation period was 5.8+/-3 and 6.1+/-1.9 years before and after CsA treatment, respectively. RESULTS: Complete remission [proteinuria <4 mg/h/m2 body surface area (BSA)], partial remission (proteinuria 4.1-40 mg/h/m2 BSA) and resistance to CsA (proteinuria > or =45 mg/h/m2 BSA) were observed in 71.7, 7.5 and 20.8% of patients, respectively. CsA-sensitive and -resistant patients differed only in the percentage of steroid responsiveness, being 66.7% in the former group and 22.7% in the later (P<0.0001). Logistic regression analysis identified steroid resistance as the only predictor of resistance to CsA (odds ratio: 12.9; P = 0.03). Hypertension, renal impairment (>30% rise of serum creatinine), gingival hyperplasia and hypertrichosis occurred in 12.3, 6.6, 22.6 and 51.9% of patients, respectively. With the exception of hypertrichosis, side effects were significantly more frequent among CsA-resistant children. We were able to stop steroids in 91 patients, of whom 31 patients relapsed. Out of 20 patients for whom CsA was intentionally discontinued while in remission, 16 patients relapsed. Of these, four (25%) were resistant to a second course of CsA. At the last follow-up, one child had developed end-stage renal failure and three had chronic renal insufficiency. CONCLUSIONS: CsA is effective in the treatment of children with idiopathic FSGS, but with a high relapse rate on drug withdrawal. Renal dysfunction and hypertension, which may be drug-induced or natural progression, are the most serious complications; therefore, close monitoring is essential.     

The sensitivity of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma

Pleural malignant mesothelioma (MM), which is an aggressive neoplasm with a high mortality, frequently manifests initially as pleural effusions. The sensitivity of cytologic examination for its diagnosis varies widely in literature and most of the figures are from earlier studies with conventional cytologic preparations. The objective of this study was to provide the current evidence on the role and sensitivity of cytologic examination of pleural fluid in the diagnosis of MM. We reviewed the cytologic findings in pleural effusions of a large series of histologically proven MM (234 cases) diagnosed in our institution between 2001 and 2008. Of all cases, 154 (66%) had cytologic material examined. A specific diagnosis of MM was rendered or suspected in 53% (79 patients). The lowest sensitivity (20%) was noticed in sarcomatoid MM cases. MM was favored over adenocarcinoma in 97% of patients with positive cytologic findings that have been confirmed with immunohistochemistry. In this series, five cases were inadequate and five cases were initially reported as atypical, whereas 65 cases (44%) were reported as negative for malignancy. On review of the cytology slides, only four cases were upgraded from benign to suspicious compared to four cases downgraded from suspicious to atypical but no significant improvement to the diagnosis could be made on revision. These data suggested that a cytologic diagnosis contributed useful information in patients with epithelioid and biphasic pleural MM. Limitations of the cytologic examination of MM should also be acknowledged. Diagn. Cytopathol. 2010;38:874–879. © 2010 Wiley‐Liss, Inc.     

Living donor liver transplantation in adults: vascular variants important in surgical planning for donors and recipients

OBJECTIVE: The purpose of our study was to explore the frequency with which surgically important hepatic vascular variants occur independently as well as in genetically related adult candidates for donation or receipt of a liver transplant. MATERIALS AND METHODS: We conducted a retrospective study of 107 adult living donor liver transplant candidates. From this pool of candidates, 50 sets of close relatives were selected to undergo transplantation. As part of the preoperative evaluation, all underwent multidetector CT angiography for evaluation of arterial and venous anatomy. Nonionic IV contrast material (180 mL) was given at a rate of 5 mL/sec, and collimations of 1.25 and 2.50 mm were used for true arterial and portal hepatic venous phase scanning, respectively. Image processing included three-dimensional volume renderings and multiplanar reformations. Two radiologists assessed the prevalence of vascular variants that were important for surgical planning and execution. RESULTS: We identified surgically important hepatic vascular variants in 70 (65%) of the 107 patients. A total of 129 variants were identified, of which 27 were important surgical considerations for recipients, 37 were important for donors, and 65 were important for both recipients (19 variants) and donors (46 variants). Of the 50 pairs of close relatives, 10 (20%) of the pairs were found to have the same hepatic vascular variant or one that was similar. However, when the pairs were set randomly, with no genetically related pairs included, similar variants were noted in 11 pairs (22%). The most common hepatic arterial variant in all candidates was an accessory right or left hepatic artery. The most common hepatic venous variant was an accessory right inferior hepatic vein. CONCLUSION: We observed a high prevalence of surgically important vascular variants in living adult candidates for living liver transplant donation and receipt. Because of the frequent occurrence, similar variants are to be expected among these sets of patients, regardless of whether they are closely related.