Background: Stenotrophomonas maltophilia (S.maltophilia) is an intrinsically drug resistant opportunistic pathogen associated with serious infections in humans. Acquired resistance to trimethoprim-sulfamethoxazole (SXT,co-trimoxazole), the main stay of therapy against S. maltophilia ,has made its treatment more problematic. Objectives: This work aimed to determine the occurrence of SXT resistance among S. maltophilia isolated from Zagazig University Hospitals in Egypt and to assess the association of sul genes and integron1 with SXT-resistant isolates. Material and Methods: Thirty-two S.maltophilia isolates were identified in this study during the period from 2013 to 2015. Screening of SXT-resistant isolates was done by Kirby-Bauer method. Minimum inhibitory concentration(MIC) values for SXT were determined by agar dilution. S. maltophilia isolates were tested for the presence of sul1, sul2, sul3, and int 1 genes by multiplex polymerase chain reaction. Results: Amongst the 32 S. maltophilia isolates, 12(37.5%) were resistant to SXT. All SXT-resistant isolates were found to harbor sul1 gene and integron1. One of these isolates had sul2 gene (1/12,8.3%). Meanwhile, sul3 gene was not detected in any of the SXT-resistant isolates. Only 2 of the 20 SXT-susceptible isolates was found to yield positive PCR results for sul1 gene, one of them gave positive result for class 1 Integron. The association of sul genes and Integrin1 with resistance to SXT had a statistically significant difference( P<0.0001). Conclusion: Our study indicated a high frequency of SXT resistance among clinical S.maltophilia isolates from Zagazig University Hospitals, in which sul genes and class 1 integron were found to have a major role.

Noroviruses (NoV) are identified as the major cause of epidemic and sporadic acute gastroenteritis. Controlling the spread of the disease needs early recognition of NoV. This study investigated the contribution of norovirus to sporadic cases of pediatric gastroenteritis in Zagazig University Hospitals and studied the performance characteristics of enzyme linked immunosorbent assay(EIA) and immunochromatographic (ICT) assay for their ability to detect NoV. Two hundred stool specimens were collected from pediatric patients with acute gastroenteritis. Samples were tested for Norovirus presence by reverse transcription PCR (RT-PCR), ICT kit and EIA. 27% of the samples showed the 338-bp portion of the RNA-dependent RNA polymerase (RdRp) gene of both Norovirus genogroups I and II by RT-PCR. The ICT assay showed high specificity (97.94%) and high sensitivity (85.18%). The EIA showed high specificity (93.8%) but low sensitivity (64.8%). In conclusion, the high detection rate of NoV as the cause of diarrhea in children reported in this study supports their addition in screenings to identify sporadic cases of acute gastroenteritis. The ICT and RIA Norovirus kits may be useful for rapid screening of stool samples from patients with acute gastroenteritis. However, RT-PCR should be considered for negative samples to be confirmed. CHARACTERISTIQUES DE PERFORMANCE DU DOSAGE IMMUNO -ENZYMATIQUE ET TEST IMMUNOCHROMATOGRAPUIQUE RAPIDE POUR LE DEPISTAGE ROUTINE DU NOROVIRUS HUMAINE