Mohammad M. Obaidat

Inactivation of Salmonella and Escherichia coli O157:H7 on sliced and whole tomatoes by allyl isothiocyanate, carvacrol, and cinnamaldehyde in vapor phase.

Little is known about the effectiveness of antimicrobials in the vapor phase for control of pathogens on the surface of fresh produce. We determined the activity of allyl isothiocyanate (AIT), cinnamaldehyde, and carvacrol against Salmonella and Escherichia coli O157:H7 on sliced and whole tomatoes. Samples were treated with various concentrations of antimicrobial in the vapor phase at 4, 10, and 25 degrees C in a closed container. AIT exhibited the highest antimicrobial activity followed by cinnamaldehyde. The lowest level of AIT (8.3 microl/liter of air) inactivated Salmonella on sliced tomatoes by 1.0 and 3.5 log at 4 and 10 degrees C, respectively, in 10 days and by 2.8 log at 25 degrees C in 10 h. This level of AIT inactivated Salmonella on whole tomatoes to the detection limit of <2 log CFU per tomato at 4 and 10 degrees C in 10 days and by 1.3 log CFU per tomato at 25 degrees C in 10 h. AIT also inactivated E. coli O157:H7 on sliced tomatoes by 3.0 log at 4 and 10 degrees C in 10 days, but there was no inactivation at 25 degrees C in 10 h. AIT reduced E. coli O157:H7 on whole tomatoes surface by 3.0 and 1.0 log CFU per tomato at 4 and 10 degrees C, respectively, in 10 days and by 2.0 log CFU per tomato at 25 degrees C in 10 h. Overall, greater inactivation occurred at 10 than at 4 degrees C and on the tomato surface than between slices. Antimicrobials in vapor phase may be useful for controlling pathogens on fresh tomatoes marketed in packages containing enclosed headspace.

Inactivation of Escherichia coli O157:H7 on the intact and damaged portions of lettuce and spinach leaves by using allyl isothiocyanate, carvacrol, and cinnamaldehyde in vapor phase.

Antimicrobials in the vapor phase might be more effective in inactivating Escherichia coli O157:H7 cells attached to leafy greens than aqueous antimicrobials. We determined the activity of allyl isothiocyanate (AIT), cinnamaldehyde, and carvacrol against E. coli O157:H7 on intact and damaged lettuce and spinach tissue. Samples were treated with various concentrations of antimicrobial in the vapor phase at 0, 4, and 10 degrees C in an enclosed container. On intact lettuce surface, the vapor of the lowest concentration of these antimicrobials inactivated >4 log of E. coli O157:H7 at 0 and 4 degrees C in 4 days and at 10 degrees C in 2 days. However, at the tissue damaged by cutting, the highest concentration reduced the population by 4 log at 0 degrees C and 2 to 4 log at 4 degrees C in 4 days. These concentrations also reduced the population of the pathogen by 1 to 3 log at 10 degrees C in 2 days. The pathogen population on spinach surface was reduced by 1 log less than on lettuce surface. However, reduction of the pathogen within spinach tissue was 2 and 3 log less than within lettuce tissue at 0 and 4 degrees C, respectively. Overall, greater inactivation occurred on lettuce than spinach leaves and on the leaf surfaces than at the damaged area. Using antimicrobials in the vapor phase may improve the safety of refrigerated leafy greens marketed in sealed packages.

Characterization of Listeria monocytogenes from three countries and antibiotic resistance differences among countries and Listeria monocytogenes serogroups.

A total of 104 Listeria monocytogenes isolates from 330 fish samples from three countries were characterized by multiplex PCR for serogrouping and virulence markers determination and tested for antibiotics resistance. A 53·8% of the isolates belonged to serogroup 1/2a, 3a; 32% belonged to 1/2b, 3b, 7; 14·4% belonged to 4b, 4d, 4e and 1% belonged to 1/2c, 3c. All isolates exhibited resistance to at least one antibiotic but the resistance rates varied among countries. The isolates exhibited high resistance to penicillin, rifampicin, clindamycin, erythromycin and tetracycline, but low resistance to amoxicillin‐clavulanic acid, streptomycin, sulfamethoxazole–trimethoprim, gentamicin, chloramphenicol and kanamycin. When comparing countries, the resistance rate for rifampicin, clindamycin, erythromycin, tetracycline, amoxicillin‐clavulanic acid varied among countries. When comparing serogroup, 1/2a, 3a exhibited the highest resistance to clindamycin, erythromycin, tetracycline and vancomycin while serogroup 4b, 4d, 4e exhibited the highest resistance to amoxicillin‐clavulanic acid. All isolates carried inlA, inlC, inlJ and lmo2672. Listeriolysin S was carried by 42 and 30% of 4b and 1/2b isolates respectively.

Heavy metals in fish from the Red Sea, Arabian Sea, and Indian Ocean: effect of origin, fish species and size and correlation among the metals.

This study determined the levels of As, Cu, Pb, and Cd in fish from Red Sea, Arabian Sea, and Indian Ocean by graphite furnace atomic absorption spectrophotometry. Metal levels were compared with international standards. The levels among fish types and origin, the relationship among metals, and the correlation between the levels and fish size were statistically tested. Fish type and origin significantly affected the levels. None of the fish contained As, Cu, and Pb above the FAO and EU codes. However, Cd exceeded the Jordanian, FAO, and EC codes from the three origins. As and Cd positively correlated with each other in Arabian Sea fish. As and Pb correlated negatively, but Cu and Cd did not correlate with fish size. This study indicates that Cd is common in fish from the three origins regardless the fish size. This warrants continuous monitoring for heavy metals, especially Cd, in internationally traded fish.

Seroepidemiology and risk factors of Toxoplasma gondii infection in undergraduate university female students in Jordan.

This study estimated the seroprevalence and risk factors for acquiring Toxoplasma gondii infection by undergraduate female university students in Jordan. A cross-sectional study from September 2013 to July 2014 analysed 202 blood samples for IgG and IgM antibodies by enzyme-linked immunosorbent assay and a semi-constructed questionnaire was completed by participants to gather information about Toxoplasma infection risk factors. T. gondii IgG antibodies were detected in 66.5% of the females. Only one sample was positive for both IgG and IgM. Using χ2 test, six factors showed significant association with T. gondii infection (P ⩽ 0.01). The multivariate logistic regression model showed that female students living in houses, wet areas, with income >US

Seroprevalence and risk factors of Hepatitis E infection in Jordan’s population: First report

750/month and using spring (untreated) water were 47.42, 10.20, 5.00, 3.25 more times at risk to be seropositive for T. gondii, respectively, compared to female students living in apartments, dry areas, with income ≤ US

Antimicrobial Resistance Percentages of Salmonella and Shigella in Seafood Imported to Jordan: Higher Percentages and More Diverse Profiles in Shigella

750/month and using treated water, respectively. This study concluded that T. gondii infection in female university students in Jordan is high and most women become infected before marriage; however, congenital toxoplasmosis is still likely to occur in Jordan. Thus, dissemination of protective measures and knowledge by healthcare professionals is essential especially for pregnant women.

Major diseases, extensive misuse, and high antimicrobial resistance of Escherichia coli in large- and small-scale dairy cattle farms in Jordan

OBJECTIVES Hepatitis E virus (HEV) is hyperendemic in many countries, but data on this virus are not available in Jordan. This study determined the seroprevalence, risk factors and zoonotic potential of HEV in a Jordanian population. METHODS A total of 450 sera samples from 8 different governorates were tested for HEV-IgG. A pre-tested and validated questionnaire was used to collect risk factor data including animal interaction and environmental exposures. RESULTS The overall seroprevalence was 30.9%. Eating undercooked meat was significantly associated with HEV seropositivity (OR=2.06, 95%CI 1.04-4.06) after controlling for age, gender, travel history and source of water. Age was also associated with HEV seropositivity; the youngest (≤14 years of age) and oldest age groups (60 and 80 years of age) had the highest prevalence (45.5% and 53.2%, respectively), compared to those between 20 to 29 years of age and 30 to 39 years of age (20.2 and 15.2%, respectively), although the small sample size among the youngest group tempers this association. There was evidence of a marginal association between owning camels and an increased odds of HEV seropositivity. Place of residence and source of drinking water were not associated with infection. CONCLUSION This is the first study to report HEV seroprevalence in Jordan and shows that HEV exposure is high in Jordan. Surveillance for acute and chronic Hepatitis E is needed to estimate the frequency of the actual disease.

Evaluation of different drying techniques on the nutritional and biofunctional properties of a traditional fermented sheep milk product.

This study determined the prevalence and antimicrobial resistance of human-specific ( Shigella spp.) and zoonotic ( Salmonella enterica ) foodborne pathogens in internationally traded seafood. Sixty-four Salmonella and 61 Shigella isolates were obtained from 330 imported fresh fish samples from Egypt, Yemen, and India. The pathogens were isolated on selective media, confirmed by PCR, and tested for antimicrobial resistance. Approximately 79 and 98% of the Salmonella and Shigella isolates, respectively, exhibited resistance to at least one antimicrobial, and 8 and 49% exhibited multidrug resistance (resistance to three or more antimicrobial classes). Generally, Salmonella exhibited high resistance to amoxicillin-clavulanic acid, cephalothin, streptomycin, and ampicillin; very low resistance to kanamycin, tetracycline, gentamicin, chloramphenicol, nalidixic acid, sulfamethoxazole-trimethoprim, and ciprofloxacin; and no resistance to ceftriaxone. Meanwhile, Shigella spp. exhibited high resistance to tetracycline, amoxicillin-clavulanic acid, cephalothin, streptomycin, and ampicillin; low resistance to kanamycin, nalidixic acid, sulfamethoxazole-trimethoprim, and ceftriaxone; and very low resistance to gentamicin and ciprofloxacin. Salmonella isolates exhibited 14 resistance profiles, Shigella isolates 42. This study is novel in showing that a human-specific pathogen has higher antimicrobial resistance percentages and more diverse profiles than a zoonotic pathogen. Thus, the impact of antimicrobial use in humans is as significant as, if not more significant than, it is in animals in spreading antibiotic resistance through food. This study also demonstrates that locally derived antimicrobial resistance can spread and pose a public health risk worldwide through seafood trade and that high resistance would make a possible outbreak difficult to control. So, capacity building and monitoring harvest water areas are encouraged in fish producing countries.

Seroprevalence, risk factors and spatial distribution of West Nile virus in Jordan

This study aimed to determine the major diseases, antimicrobial use, and resistance in commensal Escherichia coli in dairy cattle in Jordan. Forty-three (large, n = 21; small, n = 22) farms were surveyed. A validated questionnaire was administered to the herdsmen to elicit information about disease prevalence, antimicrobial knowledge, and antimicrobial use. In addition, fecal samples were collected from 5 lactating animals on each farm. A total of 520 E. coli isolates were tested for resistance to 12 antimicrobials. From the herdsmens perspective, the diseases that require use of veterinary services in large and small production systems were mastitis (51.2%), metritis (51.2%), and enteritis (39.5%), and the most commonly used antimicrobials were oxytetracycline and streptomycin. Dairy herdsmen (83.7%) reported that it is easy to purchase antimicrobials without a veterinary prescription and 97.7% of them more frequently changed the antimicrobial drug rather than increasing the dose when presented with nonresponse to treatment. Escherichia coli isolates exhibited high resistance to streptomycin (47.5%), tetracycline (45.4%), and ampicillin (34.2%). Less than 10% of isolates were resistant to chloramphenicol, kanamycin, gentamicin, ciprofloxacin, and ceftriaxone. Overall, 64.6 and 37.1% of the E. coli isolates exhibited resistance to ≥1 antimicrobial and multidrug resistance (resistance to ≥3 antimicrobial classes), respectively. The isolates exhibited 107 antimicrobial resistance profiles. This study indicates that antimicrobials are frequently misused in dairies in Jordan and that resistance among commensal E. coli toward antimicrobials of human and veterinary importance is high. Therefore, educational programs for herdsmen and enacting regulations and guidelines are necessary to promote the judicious use of antimicrobials in dairy animals in Jordan.