Global spread of epidemic methicillin-resistant Staphylococcus aureus (MRSA) is an issue of increasing clinical concern especially problematic community-associated (CA) -MRSA. However, data regarding MRSA epidemiology in regions of the Middle East, including Qatar, are still insufficient. A representative subset of 61 MRSA isolates from multinational patients from hospital in Qatar during a 2-year period (2009/2010) was examined. Molecular characterization for MRSA isolates was performed by pulsed-field gel electrophoresis (PFGE), SCCmec, spa and dru typing, and PCR for the presence of the arginine catabolic mobile element and genes for the Panton-Valentine leukocidin (PVL). Prevalence of MRSA among S. aureus isolated was 176/840 (21%). Of the 61 MRSA isolates examined, three (5%) represented hospital-acquired infection. By PFGE, 32 isolates (52%) were CA-MRSA USA300 (n = 4), USA400 (n = 3), USA1100/Southwest (SW) Pacific (n = 17) and ST80-MRSA-IV (n = 8) strains. The remaining isolates were well-known healthcare-associated EMRSA-15 (n = 8) and USA800 (n = 13). Three isolates were USA900, one was USA1200 and four were unrelated to any known strains in the international database. Unexpectedly, the USA900 isolates were all positive for PVL and USA400 isolates were PVL negative. Five of the eight EMRSA-15 isolates were PVL positive. ST80-MRSA-IV and USA300 strains exhibited typical dru types (dt10a and dt9g, respectively). Eleven different spa types were observed in this study. All USA300 isolates were arginine catabolic mobile element positive. The high prevalence of CA-MRSA, especially including USA300, in this setting underscores the importance of global epidemiological monitoring to better understand and hopefully help prevent the emergence and spread of these problem pathogens in patient populations.

Background. This study described various molecular and epidemiological characters determining antibiotic resistance patterns in Pseudomonas aeruginosa isolates. Methods. A total of 34 carbapenem-resistant P. aeruginosa clinical isolates were isolated from samples collected at a tertiary hospital in Riyadh, Saudi Arabia, from January to December 2011. Susceptibility testing, serotyping, molecular characterization of carbapenem resistance, and pulsed-field gel electrophoresis (PFGE) were performed. Results. All isolates were resistant to ceftazidime, and more than half were highly resistant (minimum inhibitory concentration (MIC) > 256 mg/L). Fifteen isolates had MIC values ≥64 mg/L for any of the carbapenems examined. Vietnamese extended-spectrum β-lactamase (VEB-1) (n = 16/34) and oxacillinase (OXA-10) (n = 14/34) were the most prevalent extended-spectrum β-lactamase and penicillinase, respectively. Verona imipenemase (VIM-1, VIM-2, VIM-4, VIM-11, and VIM-28) and imipenemase (IMP-7) variants were found in metallo-β-lactamase producers. A decrease in outer membrane porin gene (oprD) expression was seen in nine isolates, and an increase in efflux pump gene (MexAB) expression was detected in five isolates. Six serotypes (O:1, O:4, O:7, O:10, O:11, and O:15) were found among the 34 isolates. The predominant serotype was O:11 (16 isolates), followed by O:15 (nine isolates). PFGE analysis of the 34 carbapenem-resistant P. aeruginosa isolates revealed 14 different pulsotypes. Conclusions. These results revealed diverse mechanisms conferring carbapenem resistance to P. aeruginosa isolates from Saudi Arabia.

Here, 210 healthy participants including community personnel (70), clinical students (68), and healthcare workers (HCWs) (72) from the eastern region of Saudi Arabia were studied. Sixty-three Staphylococcus aureus isolates were obtained from the nares of 37% of the community personnel and 26% of the clinical students and HCWs. Methicillin-resistant S. aureus (MRSA) was found in 16% (10 isolates) of the 63 isolates; six were from HCWs. Molecular characterization revealed high clonal diversity among the isolates, with 19 different spa types, 12 clonal complexes (CCs), and seven sequence types (STs) detected. The most common strain type was USA900, CC15, and t084, seen in 11 methicillin-susceptible S. aureus (MSSA) isolates. Moreover, three novel spa types in six isolates and one novel ST in two isolates were identified, most from HCWs. Interestingly, 29 isolates were mecA positive by PCR, whereas only 10 isolates were MRSA by disk diffusion (cefoxitin resistant). Of the 19 MSSA mecA-positive isolates, 16 were PBP2a negative, leaving three unique isolates from HCWs that were mecA and PBP2a positive yet cefoxitin susceptible. Our findings highlight the importance of phenotypically and genotypically characterizing S. aureus strains isolated from healthy communities to monitor the risk of possible cross-transmission to hospitalized patients. The identified strains showed a clonal lineage relationship with previously reported S. aureus and MRSA strains acquired from hospital settings.

In this study, we examined aqueous extracts of the edible mushrooms Pleurotus ostreatus (oyster mushroom) and Lentinula edodes (shiitake mushroom). Proteome analysis was conducted using LC-Triple TOF-MS and showed the expression of 753 proteins by Pleurotus ostreatus, and 432 proteins by Lentinula edodes. Bioactive peptides: Rab GDP dissociation inhibitor, superoxide dismutase, thioredoxin reductase, serine proteinase and lectin, were identified in both mushrooms. The extracts also included promising bioactive compounds including phenolics, flavonoids, vitamins and amino acids. The extracts showed promising antiviral activities, with a selectivity index (SI) of 4.5 for Pleurotus ostreatus against adenovirus (Ad7), and a slight activity for Lentinula edodes against herpes simplex-II (HSV-2). The extracts were not cytotoxic to normal human peripheral blood mononuclear cells (PBMCs). On the contrary, they showed moderate cytotoxicity against various cancer cell lines. Additionally, antioxidant activity was assessed using DPPH radical scavenging, ABTS radical cation scavenging and ORAC assays. The two extracts showed potential antioxidant activities, with the maximum activity seen for Pleurotus ostreatus (IC50 µg/mL) = 39.46 ± 1.27 for DPPH; 11.22 ± 1.81 for ABTS; and 21.40 ± 2.20 for ORAC assays. This study encourages the use of these mushrooms in medicine in the light of their low cytotoxicity on normal PBMCs vis à vis their antiviral, antitumor and antioxidant capabilities.

This study was conducted to investigate the molecular epidemiology of resistance in Acinetobacter baumannii isolates collected at a hospital in Riyadh, Saudi Arabia, from January through December 2010. Twenty-seven A. baumannii were highly resistant (MIC > 256 μg/ml) to ceftazidime, cefepime, and aztreonam. Imipenem resistance was seen in 24 isolates, of which 18 had an minimum inhibitory concentration (MIC) >32 μg/mL. Ciprofloxacin, gentamicin, and amikacin resistance was found in 93%, 52%, and 37% of all the isolates, respectively. Moreover, 8 (30%) isolates showed colistin resistance, and 15 (56%) were found to have MICs ≥4 μg/mL for tigecycline. The frequency of ADC, GES-1, GES-11, and GES-5 were 96.3% (n = 26), 18.5% (n = 5), 11% (n = 3), and 3.7% (n = 1), respectively. OXA-23 was found in 63% (n = 17) of the isolates; ISAba1 was found upstream of OXA-23 in 16. OXA-24/40 was detected in only one strain. Multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) analysis revealed that the 27 strains were distributed in 8 sequence types (STs) and 16 clonal pulsotypes (A-P). Five singleton STs were identified, including ST15 and ST113-ST116. The emergence of multidrug-resistant A. baumannii is becoming a major concern in Saudi Arabia. Metallo-β-lactamases have no role in carbapenem resistance in this collection. The spread of OXA-23 in our strains occurred across different STs and pulsotypes, unlike what has been observed in many other countries. PFGE typing was more discriminatory than MLST. The high frequency of colistin and tigecycline resistance found in the isolates calls for continuous monitoring. This study describes the first identification of GES-5 conferring carbapenem resistance in A. baumannii.

Acinetobacter baumannii is currently considered as one of the most common successful pathogens in the healthcare system due to its ability to quickly develop resistance. Ten carbapenem-resistant A. calcoaceticus-baumannii complex were isolated from the eastern region, Saudi Arabia in 2014. All isolates were resistant to ciprofloxacin, however, 8 of 10 isolates were tigecycline resistant. Susceptibility test was also carried out for three aminoglycosides, resistance to gentamicin was 80%, amikacin was 90%, and tobramycin was 50%. Colistin susceptibility was seen in all isolates. The 10 isolates harbored bla and ISAba1 and 9 of them also carried bla. Three isolates of 10 harbored bla coding for NDM metallo-β-lactamase (MBL) with coexistence of bla together with either bla or bla or both. Those three isolates exhibited negative Etest MBL screening test. Pulsed-field gel electrophoresis revealed the high clonal variability of the isolates, although two isolates were indistinguishable. The risk of dissemination of carbapenem resistance through presence of ISAba1 upstream of OXA-23-like in all isolates raises the concern about emergence of higher carbapenem prevalence rates in the future in our region. This study also demonstrated the importance of molecular surveillance to provide accurate and reliable data about the resistance rates of A. baumannii. Finally, the high incidence of NDM-1 among our isolates requires a routine surveillance to monitor the future prevalence of this enzyme in the region.

In this study, we investigated aqueous extracts of three edible mushrooms: Agaricus bisporus (white button mushroom), Pleurotus columbinus (oyster mushroom), and Pleurotus sajor-caju (grey oyster mushroom). The extracts were biochemically characterized for total carbohydrate, phenolic, flavonoid, vitamin, and protein contents besides amino acid analysis. Triple TOF proteome analysis showed 30.1% similarity between proteomes of the two Pleurotus spp. All three extracts showed promising antiviral activities. While Pleurotus columbinus extract showed potent activity against adenovirus (Ad7, selectivity index (SI) = 4.2), Agaricus bisporus showed strong activity against herpes simplex II (HSV-2; SI = 3.7). The extracts showed low cytotoxicity against normal human peripheral blood mononuclear cells (PBMCs) and moderate cytotoxicity against prostate (PC3, DU-145); colorectal (Colo-205); cecum carcinoma (LS-513); liver carcinoma (HepG2); cervical cancer (HeLa); breast adenocarcinoma (MDA-MB-231 and MCF-7) as well as leukemia (CCRF-CEM); acute monocytic leukemia (THP1); acute promyelocytic leukemia (NB4); and lymphoma (U937) cell lines. Antioxidant activity was evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging, 2,2′-Azinobis-(3-Ethylbenzthiazolin-6-Sulfonic Acid) ABTS radical cation scavenging, and oxygen radical absorbance capacity (ORAC) assays. The three extracts showed potential antioxidant activities with the maximum activity recorded for Pleurotus columbinus (IC50 µg/mL) = 35.13 ± 3.27 for DPPH, 13.97 ± 4.91 for ABTS, and 29.42 ± 3.21 for ORAC assays.

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