Paratuberculosis (pTB) is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP) in a wide variety of domestic and wild animals. Control of pTB is difficult due to the lack of sensitive, efficacious and cost-effective diagnostics and marker vaccines. Microscopy, culture, and PCR have been used for the screening of MAP infection in animals for quite a long time. Besides, giving variable sensitivity and specificity, these tests have not been considered ideal for large-scale screening of domestic livestock. Serological tests like ELISA easily detects anti-MAP antibodies. However, it cannot differentiate between the vaccinated and infected animals. Nanotechnology-based diagnostic tests are underway to improve the sensitivity and specificity. Newer generation diagnostic tests based on recombinant MAP secretory proteins would open new paradigm for the differentiation between infected and vaccinated animals and for early detection of the infection. Due to higher seroreactivity of secretory proteins vis-a-vis cellular proteins, the secretory proteins may be used as marker vaccine, which may aid in the control of pTB infection in animals. Secretory proteins can be potentially used to develop future diagnostics, surveillance and monitoring of the disease progression in animals and the marker vaccine for the control and eradication of pTB.
Background: Global increase in the prevalence of virulent extended-spectrum betalactamase (ESBL)-producing uropathogenic Escherichia coli (UPEC), which is also multidrug resistant (MDR), leads to increase in severity of urinary tract infections (UTIs), decrease in the efficacy of the first-line antibiotics, and therefore increase in the morbidity and mortality rates. Methods: We investigated the distribution of ESBL-producing UPEC in 78 E. coli isolates from community-acquired UTI patients in southern Iran. The prevalence of three major ESBL genes, antimicrobial resistance patterns against 15 conventional antibiotic disks, and the presence of 11 important virulence genes that involve in the development and progression of UTIs were evaluated in these isolates. Results: Of the UPECs, 34.6% were ESBL-positive and 96.3% of the ESBL-producers were MDR. Among the ESBL-producers, 100% harbored bla CTX-M , 63% harbored bla SHV , and 11.1% harbored bla TEM genes. ESBL-producers showed a higher level of resistance to the tested cephalosporins, fluoroquinolones, trimethoprim-sulfamethoxazole, and tetracycline than non-ESBL producers. All isolates were resistant to the tested penicillins. Prevalence of resistance to about two-third of the tested antibiotics was higher than 50% and 93.6% of the isolates were MDR. High prevalence of virulence factors particularly the adhesins (82.1% csgA, 73.1% fimH genes) and siderophore (73.1% sitA gene) was seen in the UPECs. But fortunately in MDR isolates, the virulence score and prevalence of hemagglutinin (tsh), hemolysin toxin (hlyD) and invasin (ibeA) genes were lower than in non-MDR UPECs. Shockingly, among the 15 common antibiotics, only nitrofurantoin (<20% resistance) could be recommended as an appropriate drug for the treatment of UTIs due to our ESBL-producer UPECs. Conclusion: The alarming level of virulent MDR ESBL-producer E. coli strains in this study necessitates the performing of an antibiotic stewardship program, regional screening of ESBL-producers and their virulence properties to select appropriate antibiotic, or designing new therapeutic methods for UTIs by inactivation of the essential virulence factors of UPECs.
Background Salmonella enterica serovar Enteritidis (S. Enteritidis) is one of the most common serovars, associated with human salmonellosis. The food-borne outbreak of this bacterium is mainly related to the consumption of contaminated poultry meat and poultry products, including eggs. Therefore, rapid and accurate detection, besides investigation of virulence characteristics and antimicrobial resistance profiles of S. Enteritidis in poultry and poultry egg samples is essential. A total of 3125 samples (2250 poultry and 875 poultry egg samples), sent to the administrative centers of veterinary microbiology laboratories in six provinces of Iran, were examined for Salmonella contamination, according to the ISO 6579 guideline. Next, duplex PCR was conducted on 250 presumptive Salmonella isolates to detect invA gene for identification of the genus Salmonella and sdf gene for identification of S. Enteritidis. Subsequently, the S. Enteritidis isolates were examined for detection of important virulence genes (pagC, cdtB, msgA, spaN, tolC, lpfC, and spvC) and determination of antibiotic resistance patterns against nalidixic acid, trimethoprim-sulfamethoxazole, cephalothin, ceftazidime, colistin sulfate, and kanamycin by the disk diffusion method. Results Overall, 8.7 and 2.3% of poultry samples and 6.3 and 1.3% of eggs were contaminated with Salmonella species and S. Enteritidis, respectively. The invA and msgA genes (100%) and cdtB gene (6.3%) had the highest and the lowest prevalence rates in S. Enteritidis isolates. The spvC gene, which is mainly located on the Salmonella virulence plasmid, was detected in 50.8% of S. Enteritidis isolates. The S. Enteritidis isolates showed the highest and the lowest resistance to nalidixic acid (87.3%) and ceftazidime (11.1%), respectively. Unfortunately, 27.0% of S. Enteritidis isolates were multidrug-resistant (MDR). Conclusion The rate of contamination with Salmonella in the poultry and egg samples, besides the presence of antimicrobial resistant and MDR Salmonella isolates harboring the virulence genes in these samples, could significantly affect food safety and subsequently, human health. Therefore, continuous monitoring of animal-source foods, enhancement of poultry farm control measures, and limiting the use of antibiotics for prophylactic purposes in food producing animals, are essential for reducing the zoonotic risk of this foodborne pathogen for consumers and also choosing effective antibiotics for the treatment of salmonellosis.
SUMMARY:The aim of this study was to determine the resistance patterns of uropathogenic Escherichia coli (UPEC) isolates and to investigate the frequency of several virulence genes, including fimH, papA, hlyD, cnf-1, sitA, and tsh, among various phylogenetic groups of UPEC isolates. A total of 85 E. coli isolates were recovered from urine samples from outpatients with a clinical diagnosis of uncomplicated urinary tract infections. A molecular approach to examine the antimicrobial resistance patterns was employed using PCR and the disc diffusion method. The detected frequencies of the virulence factor genes determined using PCR were: fimH (34.1z), papA (9.4z), hlyD (21.2z), cnf-1 (3.5z), sitA (15.3z), and tsh (27.1z). These results revealed that the isolates were resistant to trimethoprimsulfamethoxazole (SXT) (74.1z), cefotaxime (CTX) (68.2z), and amoxicillin-clavulanic acid (AMC) (94.1z), and they were relatively less resistant to N (56.5z). According to these results, further investigation is needed to determine exactly whether or not SXT, CTX, and AMC are appropriate antibiotics for the treatment of UPEC infections in southern Iran. Although these results demonstrate that fimH is the most frequent virulence gene among UPEC isolates, the high prevalence of isolates that do not encode fimH (75.9z) and the relatively low frequency of isolates that carry other virulence genes require further investigation to clarify the role of the other potential virulence factors in the pathogenesis of these isolates.
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