Salwa Bdour

The stemness in keratinocyte stem cells (KSCs) is determined by their gene expression patterns. KSCs are crucial in maintaining epidermal homeostasis and wound repair and are widely used candidates for therapeutic applications. Although several studies have reported their positive identifiers, unique biomarkers for KSCs remain elusive. Here, we aim to identify potential candidate stem cell markers. Human epidermal keratinocytes (HEKs) from neonatal foreskin tissues were isolated and cultured. Single-cell clonal analysis identified and characterized three types of cells: KSCs (holoclones), transient amplifying cells (TACs; meroclones), and differentiated cells (DSCs; paraclones). The clonogenic potential of KSCs demonstrated the highest proliferation potential of KSCs, followed by TACs and DSCs, respectively. Whole-transcriptome analysis using microarray technology unraveled the molecular signatures of these cells. These results were validated by quantitative real-time polymerase chain reaction and flow cytometry analysis. A total of 301 signature upregulated and 149 downregulated differentially expressed genes (DEGs) were identified in the KSCs, compared to TACs and DSCs. Furthermore, DEG analyses revealed new sets of genes related to cell proliferation, cell adhesion, surface makers, and regulatory factors. In conclusion, this study provides a useful source of information for the identification of potential SC-specific candidate markers.

Background: Acinetobacter baumannii is an opportunistic pathogen causing community-acquired and nosocomial infections. Dissemination of infection to blood causes septicemia associated with serious morbidity and mortality of patients. Neutrophils are essential for the control of A. baumannii infections by different mechanisms, including oxidative burst. Aims: This study was conducted as an attempt to determine the effect of septicemic and non-septicemic A. baumannii isolates on the phagoburst response of neutrophils. Methods: Neutrophils were isolated from an immunocompetent individual; chronic myeloid leukemia (CML) and lung solid tumor (ST) patients. The phagoburst response of these neutrophils to various strains of A. baumannii isolated from septic and non-septic patients was investigated by flow cytometer. Results: The presence of this pathogen lowered the phagoburst response in the different types of neutrophils compared to their response to the opsonized Escherichia coli. The phagoburst response of the neutrophils from the immunocompetent individual was significantly higher than that of neutrophils from the immunodeficient patients when stimulated by the septicemic or nonsepticemic A. baumannii isolates. The isolate type (septicemic or non-septicemic) had no significant effect on the neutrophil phagoburst response of the immunocompetent individual and a significant effect on the phagoburst response of neutrophils from the immunodeficient patients. The phagoburst response of the neutrophils from the immunodeficient patients stimulated by septicemic A. baumannii isolates was significantly lower than that when neutrophils stimulated by the nonsepticemic isolates. Also, there was a significant difference in the phagoburst response of neutrophils from the CML and ST patients when stimulated by the septicemic and non-septicemic isolates. This observation might be due to the combined effect of virulent A. baumannii isolates and the chemotherapy regime the patient was undertaking. Conclusion: The results suggest that both the isolate type and the source of neutrophils have a significant effect on the neutrophil phagoburst response. The potential virulence of the septicemic A. baumannii isolates and dissemination to blood may be dependent on the host’s immune status and the neutrophils phagoburst response.

Torque teno virus (TTV) is the most common component of the human blood virobiota. Little is known, however, about the prevalence of TTV in humans and the most common farm domesticates in Jordan, or the history and modality of TTV transmission across species lines. We therefore tested sera from 396 Jordanians and 171 farm animals for the presence of TTV DNA using nested 5′-UTR-PCR. We then performed phylogenetic, ordination and evolutionary diversity analyses on detected DNA sequences. We detected a very high prevalence of TTV in Jordanians (~96%); much higher than in farm animal domesticates (~29% pooled over species). TTV prevalence in the human participants is not associated with geography, demography or physical attributes. Phylogenetic, ordination and evolutionary diversity analyses indicated that TTV is transmitted readily between humans across the geography of the country and between various species of animal domesticates. However, the majority of animal TTV isolates seem to derive from a single human-to-animal transmission event in the past, and current human-animal transmission in either direction is relatively rare. In conclusion, animal TTV in Jordan is historically derived from human variants; however, ongoing human-animal TTV exchange is minimal and zoonotic infection seems to be of limited importance.

The prevalence, seasonality and genotypes of rotavirus circulating in Jordan were determined to provide data useful for the implementation of a rotavirus vaccine in the national childhood vaccination program. During 2006/07, rotavirus was detected in 35% of hospitalized children, and 88% of the cases occurred in children aged between 6 and 23 months. Rotavirus infection persisted throughout the year and peaked in winter. Seven genotypes were identified by RT-PCR and sequencing: G1P[8], G9P[8], G2P[4], G1P[4], G3P[8], G4P[8] and G9P[6], which represented 69%, 8.8%, 2.4%, 2.0%, 1.2%, 0.4% and 0.4% of the rotavirus strains, respectively. Thirteen percent and 2.8% of the total strains were partially typed or untypeable, respectively. Eighty-eight percent and 12% of the rotavirus strains possessed a long and short electropherotype, respectively. As more than 90% of the rotavirus strains circulating in Jordan possessed the G1 or P[8]-genotype, it is concluded that the implementation of the rotavirus vaccine in the framework of the national childhood vaccination program of Jordan would most likely be very effective. Continuous monitoring of the currently circulating genotypes in Jordan should be encouraged.

This study was carried out to determine the prevalence, seasonal distribution of RSV, the signs and symptoms associated with it in Jordan. A total of 200 nasopharyngeal aspirates were obtained from hospitalized children (below 2 years old). RSV was detected in 12.5% of patients using direct immunofluorescence technique. Most infections were associated with bronchilolitis, and higher rates of hypoxemia, retractions, tachypnea, hyperinflation and interstitial infiltrates in 1 to 3 months old children. RSV showed a clear temporal periodicity. The epidemic began in December and disappeared in March with a peak of incidence during February 2003 and January 2004. The seasonal distribution showed a significant correlation with temperature, rainfall and relative humidity. This study provides further information on RSV epidemiology which could help in planning of prevention and control programs in Jordan, distinguishing RSV infections on the basis of the clinical picture and considering RSV between December and March each year.

A total of 100 Jordanian clinical Staphylococcus aureus isolates was analysed for the presence of the enterotoxin genes sea, seb, sec, sed and see using multiplex PCR. Twenty-three isolates (23 %) were potentially enterotoxigenic. The prevalence of sea, sec and sea plus sec among the total clinical isolates was 15, 4 and 4 %, respectively. None of the isolates harboured sed, seb or see genes. S. aureus isolates were subjected to DNA fingerprinting by randomly amplified polymorphic DNA (RAPD) analysis to test whether isolates harbouring the toxin genes were genetically clustered. A total of 13 genotypes was identified at a 47 % similarity level. Genotypes I and V accounted for the largest number of enterotoxigenic isolates (19 %). This study has demonstrated the genetic diversity of Jordanian clinical S. aureus isolates and shown that the presence of the toxin genes is not genotype specific.