Use of ginger extract and bacterial inoculants for the suppression of Alternaria solani causing early blight disease in Tomato.

Early blight (EB), caused by Alternaria solani, is a serious problem in tomato production. Plant growth-promoting rhizobacteria promote plant growth and inhibit plant disease. The present study explored the bio-efficacy of synergistic effect of rhizobacterial isolates and ginger powder extract (GPE) against tomato EB disease, singly and in combination. Six fungal isolates from symptomatic tomato plants were identified as A. solani on the basis of morphological features i.e., horizontal septation (6.96 to 7.93 µm), vertical septation (1.50 to 2.22 µm), conidia length (174.2 to 187.6 µm), conidial width (14.09 to 16.52 µm), beak length (93.06 to 102.26 µm), and sporulation. Five of the twenty-three bacterial isolates recovered from tomato rhizosphere soil were nonpathogenic to tomato seedlings and were compatible with each other and with GPE. Out of five isolates tested individually, three isolates (St-149D, Hyd-13Z, and Gb-T23) showed maximum inhibition (56.3%, 48.3%, and 42.0% respectively) against mycelial growth of A. solani. Among combinations, St-149D + GPE had the highest mycelial growth inhibition (76.9%) over the untreated control. Bacterial strains molecularly characterized as Pseudomonas putida, Bacillus subtilis, and Bacillus cereus and were further tested in pot trials through seed bacterization for disease control. Seeds treated with bacterial consortia + GPE had the highest disease suppression percentage (78.1%), followed by St-149D + GPE (72.2%) and Hyd-13Z + GPE (67.5%). Maximum seed germination was obtained in the bacterial consortia + GPE (95.0 ± 2.04) followed by St-149D + GPE (92.5 ± 1.44) and Hyd-13Z + GPE (90.0 ± 2.04) over control (73.8 ± 2.39) and chemical control as standard treatment (90.0 ± 2). Ginger powder extracts also induce the activation of defence-related enzymes (TPC, PO, PPO, PAL, and CAT) activity in tomato plants. These were highly significant in the testing bacterial inoculants against A. solani infection in tomato crops.

Antimicrobial resistance profile of Staphylococcus aureus and its in-vitro potential inhibition efficiency.

BACKGROUND: Staphylococcus aureus infection is associated with hospitals and caused mortality in hospitalized patients. These biofilm-forming bacteria are associated with chronic infections in patients. OBJECTIVES: To investigate the biofilm forming ability of multidrug resistant bacteria associated with hospital environment and analyze anti-biofilm compounds from the natural sources. METHODS: The hospital wastewater sample was used for the isolation of drug resistant S. aureus strains. The biofilm producing ability was analyzed and the isolated S. aureus strains were tested for antibiotic susceptibility patterns against various antibiotics. To screen suitable antibacterial agent, essential oil was extracted from Teucrium polium by hydrodistillation method and the compounds were determined by GC-MS analysis. The antimicrobial potential of essential oil was studied against S. aureus strains by disc diffusion method and biofilm inhibition property of essential oil was analyzed. The synergistic activity of essential oil was also analyzed. RESULTS: A total of 13 S. aureus strains were isolated and almost all bacterial strains showed biofilm forming ability. Most of the isolated S. aureus strains showed resistance to ampicillin, cefoxitin, ciprofloxacin, erythromycin, gentamicin, chloramphenicol and vancomycin. The extracted essential oil showed pale yellow in colour with pleasant odour and the yield was about 0.9%. Twenty-two compounds were detected in GC-MS analysis which shared about 96% of the total determined chemical composition. The major compounds determined were α-pinene (5.3%), linalool (16.2%), caryophyllene (10.04%), germacrene D (37.2%), and ß-eudesmol (6.1%). The extracted essential oil showed antibacterial activity and the zone of inhibition varied from 15 ± 1 to 21 ± 2 mm against S. aureus strains. The essential oil showed antibiofilm activity and synergistic activity against S. aureus strains. CONCLUSIONS: This study analyzed biofilm forming ability of drug resistant S. aureus strains isolated from the hospital wastewater. The isolated bacterial strains showed resistance against various tested antibiotics. The essential oil extracted from T. polium showed antibacterial and anti-biofilm activity.

Methicillin and multidrug resistant pathogenic Staphylococcus aureus associated sepsis in hospitalized neonatal infections and antibiotic susceptibility.

BACKGROUND: Neonatal infection is infection of the newborn or neonate acquired in first four weeks of life or during prenatal development. Microorganism associated neonatal infections caused severe mortality in recent years. It is developed either prenatally or within 28 days of neonatal period. This infection is mainly transmitted from mother to child through placenta. It has been well associated with the premature rupture of membranes which markedly enhances the risk of neonatal sepsis. METHODS: The present experiment was designed to analyze bacteria, their antibiotic resistance pattern and possible risk factors among neonatal patients with sepsis. The neonates specimen was subjected for the isolation of bacteria and antibiotic susceptibility test. Neonates were analyzed with previous clinical history such as, previous admission in hospitals, mode of delivery, birth weight, and feeding type in accordance with questionnaire. RESULTS: Gram-positive bacteria isolates were found to be high (79 strains, 64.22%) than the Gram-negative bacteria (44 strains, 32.5%). Staphylococcus aureus (33 strains, 26.9%) was the major Gram-positive groups of bacteria. Multidrug resistance analysis accounted more S. aureus (26.9%) and 5 strains (15.15%) showed methicillin resistance, whereas 84.9% were found to be sensitive to methicillin. CONCLUSION: In this study, S. aureus and K. pneumoniae were the highest frequency of isolates. The overall percentage of multidrug resistant isolates was high in this study. Highest degree of resistance was observed in ampicillin against all isolates. Hence much attention is required while diagnosing sepsis among neonates. To analyze the risk for neonatal sepsis, it is not preferable for caesarian mode of delivery. Moreover, frequent screening of mother, suitable prenatal care of newborns with proper clinical interventions isthe key elements to control sepsis.

Detection of Campylobacter jejuni and Salmonella typhimurium in chicken using PCR for virulence factor hipO and invA genes (Saudi Arabia).

Campylobacter jejuni and Salmonella typhimurium are the leading causes of bacterial food contamination in chicken carcasses. Contamination is particularly associated with the slaughtering process. The present study isolated C. jejuni and S. typhimurim from fifty chicken carcass samples, all of which were acquired from different companies in Riyadh, Saudi Arabia. The identification of C. jejuni was performed phenotypically by using a hippurate test and genetically using a polymerase chain reaction with primers for 16S rRNA and hippurate hydrolase (hipO gene). For the dentification of S. typhimurim, a serological Widal test was carried out using serum anti-S. typhimurium antibodies. Strains were genetically detected using invA gene primers. The positive isolates for C. jejuni showed a specific molecular size of 1448 bp for 16S rRNA and 1148 bp for hipO genes. However, the positive isolates of the invA gene exhibited a specific molecular size at 244 bp using polymerase chain reaction (PCR). Comparing sequencing was performed with respect to the invA gene and the BLAST nucleotide isolates that were identified as Salmonella enterica subsp. enterica serovar typhimurium strain ST45, thereby producing a similarity of 100%. The testing identified C.jejuni for hippuricase, GenBank: Z36940.1. While many isolates of Salmonella spp. that contained the invA gene were not necessarily identified as S. typhimurim, the limiting factor for the Widal test used antiS. typhimurum antibodies. The multidrug resistance (MDR) of C. jejuni isolates in chickens was compared with the standard C. jejuni strain ATCC 22931. Similarly, S. typhimurium isolates were compared with the standard S. typhimurium strain ATCC 14028.

Prevalence of methicillin-resistant (mecA gene) and heat-resistant Staphylococcus aureus strains in pasteurized camel milk.

Staphylococcus aureus is a significant opportunistic pathogen in humans, dairy cattle, and camels. The presence of antibiotic-resistant and heat-resistant bacteria in camel milk has become a potential public health issue. The phenotypic and molecular characterization of methicillin-resistant staphylococcal strains recovered from pasteurized camel milk distributed in retail markets of Saudi Arabia was assessed. A total of 100 samples were collected between March and May 2017. Out of the 20 S. aureus isolates that were recovered from the pasteurized camel milk, 10 were found to be resistant to cefoxitin (30 µg) and, thus, were designated as methicillin-resistant strains. The resistance ratio of methicillin-resistant S. aureus isolates for a different class of antibiotics was determined by performing the antimicrobial susceptibility test and was estimated to be approximately 60%. Polymerase chain reaction assay was performed to amplify the methicillin-resistant gene mecA, and furthermore, nucleotide sequencing was performed to detect and verify the presence of methicillin-resistant strains. Upon sequencing the putative S. aureus methicillin-resistant strains, we obtained 96 to 100% similarity to the penicillin-binding protein 2a gene (mecA) of the S. aureus strain CS100. Moreover, the 10 methicillin-resistant S. aureus isolates were also identified to be heat resistant and were stable at temperatures up to 85°C for 60 s, with 3 isolates being heat resistant even at 90°C for 60 or 90 s. The mean decimal reduction time (D85 value) was 111 s for all the 10 isolates. No difference was observed in the profile of total protein between the 10 methicillin- and heat-resistant S. aureus isolates and the S. aureus strain ATCC 29737, which was determined by sodium dodecyl sulfate-PAGE analyses. Therefore, we could conclude that a relatively high percentage of the tested pasteurized camel milk samples were contaminated with S. aureus (20%) and methicillin- and heat-resistant S. aureus (10%).

Prevalence and antibiotic resistance of Listeria monocytogenes in camel meat.

In the present study, a total of 50 raw camel meat samples were analyzed for the presence of Listeria monocytogenes. The isolates were characterized via morphological and culture analyses; identification of isolates was confirmed by polymerase chain reaction (PCR) and sequencing of the listeriolysin O gene. The API Listeria system was used for further chemical identification and verification of the strains. L. monocytogenes was identified in eight raw camel meat samples, which was the highest incidence (16%) of contamination, followed by L. seeligeri 3(6%), L. innocua and L. welshimeri 2 (2% each), and L. grayi 1 (1%). According to Basic Local Alignment Search Tool (BLAST) analysis, isolated strains that were positive for the listeriolysin O gene were >99% similar to the published database sequences for L. monocytogenes strain LM850658 (sequence ID: CP009242.1). We studied the antibiotic resistance profile of the L. monocytogenes strains with common antibiotics used to treat human listeriosis and demonstrated that almost all strains tested were susceptible to the antibiotics.

Molecular detection of methicillin heat-resistant Staphylococcus aureus strains in pasteurized camel milk in Saudi Arabia.

Antibiotic- and heat-resistant bacteria in camel milk is a potential public health problem. Staphylococcus aureus (S. aureus) is an opportunistic pathogen in humans, dairy cattle and camels. We characterized the phenotype and genotype of methicillin-resistant staphylococcal strains recovered from pasteurized and raw camel milk (as control) distributed in the retail markets of Saudi Arabia. Of the 100 samples assessed between March and May 2016, 20 S. aureus isolates were recovered from pasteurized milk, 10 of which were resistant to cefoxitin, and as such, were methicillin-resistant. However, raw camel milk did not contain methicillin-resistant S. aureus (MRSA). Antimicrobial susceptibility tests showed that the resistance ratio for other antibiotics was 60%. We performed a polymerase chain reaction (PCR) assay using primers for the methicillin-resistant gene mecA and nucleotide sequencing to detect and verify the methicillin-resistant strains. Basic local alignment search tool (BLAST) analysis of the gene sequences showed a 96-100% similarity between the resistant isolates and the S. aureus CS100 strain's mecA gene. Ten of the methicillin-resistant isolates were heat-resistant and were stable at temperatures up to 85°C for 60 s, and three of these were resistant at 90°C for 60 or 90 s. The mean decimal reduction time (D85-value) was 111 s for the ten isolates. Sodium dodecyl sulfate (SDS)/polyacrylamide gel electrophoresis (PAGE) showed that there was no difference in the total protein profiles for the ten methicillin heat-resistant S. aureus (MHRSA) isolates and for S. aureus ATCC 29737. In conclusion, a relatively high percentage of the tested pasteurized camel milk samples contained S. aureus (20%) and MHRSA (10%).