Desiccation survival in Salmonella enterica, Escherichia coli and Enterococcus faecium related to initial cell concentration and cellular components

Salmonella enterica is well-known for its ability to survive and persist in low-moisture environments. Previous studies have indicated a link between the initial cell concentration and the population of Salmonella that survive upon desiccation and subsequent storage; however, how the initial cell concentration affects survival is unknown. This study examined the basis of this phenomena and whether it occurred in other microorganisms, specifically Shiga toxigenic Escherichia coli (STEC), and Enterococcus faecium . Salmonella, STEC, and E. faecium were grown as lawns on TSAYE and harvested using buffered peptone water (BPW). To determine recovery at different initial cell levels, cultures were diluted to 9, 7, and 5 log CFU/mL and applied to filters. Filters were dried for 24 h, then stored for 28 d at 25°C/33% RH. During storage, cells were recovered from filters using BPW and cultivated on TSAYE. Both Salmonella and E. coli , but not E. faecium , showed non-proportional recovery. Less viability remained with lower initial starting population after 24 h desiccation such that ≥10 log CFU/mL were recovered when 11 log CFU/mL was desiccated, but <3 log CFU/mL were recovered when 5 log CFU/mL was desiccated. Once dried, persistence did not appear affected by initial cell concentration. When dead cells (heat-treated) were added to the diluent, recovery of Salmonella was proportional with respect to the initial cell concentration. To further examine the response on desiccation, Salmonella was diluted in BPW containing one of 11 different test cell components related to quorum sensing or known to affect desiccation resistance to assess recovery and persistence. Of the 11 additions only cell debris fractions, cell-free extract, and peptidoglycan improved recovery of Salmonella . Desiccation survival appears related to cell wall components, however, the exact mechanism affecting survival remains unknown.

ISOLASI DAN IDENTIFIKASI Vibrio parahaemolyticus PADA UDANG VANAME (Litopenaeus vannamei) PENYEBAB PENYAKIT VIBRIOSIS

Penelitian ini bertujuan sebagai informasi yang berkaitan dengan isolasi identifikasi Vibrio parahaemolyticus yang dilakukan sebagai langkah dalam menjamin keamanan pangan hasil perikanan sehingga aman untuk di konsumsi. Penelitian ini dilakukan dengan metode ISO/TS 21872-1:2007 langkah yang dilakukan yaitu pre enrichment dengan menggunakan sampel sebanyak 25gram yang dilarutkan dengan menggunakan alkaline saline peptone water 225ml, lalu diinkubasi selama 6jam dengan suhu 41,50C sedangkan untuk sampel segar memerlukan waktu±1 jam, selanjutnya enrichment dengan suhu 41,5 0C selama 18 jam ± 1 jam, selanjutnya dilakukan isolasi serta identifikasi dengan menggunakan media Thiosulfate Citrate Bile Salts Sucrose (TCBS), lau dilakukan inkubasi pada suhu 37 0C selama 24 jam ± 3 jam, setelah itu dilakukan pengamatan dengan ciri-ciri koloni pada V. parahaemolyticus lembut warna hijau (sukrosa negatif) dengan diameter 2-3mm, dan dilakukan uji biokimia dengan melakukan inokulasi pada koloni dengan menggunakan media saline nutrient agar,lalu dilakukan pemeriksaan uji biokimia. Hasil penelitian dari pemeriksaan sampel yang dilakukan di laboratorium Stasiun Karantina Ikan Pengendalian Mutu dan Keamanan Hasil Perikanan Medan II (SKIPM) dapat disimpulkan bahwa dari 7 sampel yang di uji tidak ada yang menunjukkan hasil positif bakteri Vibrio parahaemolyticus dari sampel laut, untuk media dan reagen uji yang digunakan benar dan sesuai dengan pengujian pada kontrol positif bakteri Vibrio parahaemolyticus

Most Probable Number of Escherichia Coli in Fresh Milk at KPSP Ijen Makmur, Licin Sub-District, Banyuwangi

The study aimed to identify the total number of E. coli used in fresh cow milk in KPSP Ijen Makmur. The sample was used by as many as 16 samples from a group of cattle farmers. E. coli analyzed using Most Probable Number (MPN), 3 series of tubes. Before continuing the MPN test the milk must be diluted, 25 ml of milk was poured into the dilution of the 225ml peptone water buffered then homogenized for 2 minutes. MPN consist of presumptive coliform test if positive was found of gas and was cloudy, presumptive faecal coliform test positive was found in the gas and was cloudy, confirmed E.coli test if there was a black colony with or metallic green, continued by a biochemical test with red ring-positive Indole, Methyl Red positive the color is red, negative Voges Paskauer if there is no change in color, and negative citrate will turn green. Results showed that from the 16 samples of fresh milk used there were 7 samples of fresh milk that exceeded the contamination limit E. coli or < 3 apm /ml. Conclusion, number of E. coli in fresh milk at KPSP Ijen Makmur 43.75% of the total sample exceeded maximum contamination.

Assessing the Efciency of Detection of Vibrio cholerae Genetic Determinants Through Waterbody Vibrioflora Monitoring System

Objective of the study was to assess the effectiveness of PCR screening of Vibrio cholerae genetic determinants in samples from surface water reservoirs for optimization of the cholera microbiological monitoring system.Materials and methods. The study was carried out as a part of the vibrioflora monitoring in surface water bodies in Irkutsk city. The study design included: 1) PCR screening of V. cholerae genetic determinants in nutrient-enriched (1 % peptone water) samples from surface water reservoirs during the monitoring period (824 samples); 2) studying of the V. cholerae DNA accumulation dynamics applying PCR assay of the samples from surface water reservoirs during cultivation on the enriched media (16 samples in dynamics); 3) experimental study of the detected V. cholerae concentrations in samples from surface water reservoirs. Species-specifc (hlyA, toxR) and serogroup-specifc (wbeT, wbfR) V. cholerae determinants were indicated in PCR with hybridization-fluorescent and electrophoretic detection.Results and discussion. At the frst stage it was found that the proportion of the positive samples through PCR screening (33.9 %) exceeded the percentage of the positive samples in bacteriological examination (19.3 %) (t=6.6; p<0,01). In the assessment of DNA accumulation dynamics, a decrease in the threshold cycle (Ct) by 1.2–5.2 times was recorded, indicating an increase in the V. cholerae concentration and proving the detection of genetic determinants of viable forms during PCR screening. An extended study of PCR-positive but bacteriologically negative samples made it possible to additionally isolate 4 V. cholerae cultures. However, there were no differences in the sensitivity of PCR screening and bacteriological analysis in the experiment with water samples artifcially contaminated with V. cholerae unlike the analysis of the enriched native samples. It can be determined by the metabolism and adaptation peculiarities of the microorganism in different environmental conditions. The results of the integrated study indicate the epidemiological effectiveness of PCR screening which gives grounds to recommend its application in monitoring studies of vibrioflora from environment after preliminary enrichment on liquid nutrient media in the work of federal, territorial, and regional laboratories.

Determination of Microbial Pathogens and its Abundance in Fresh Kunun-Zaki Drinks: Huge Threat to Public Health

This study investigated the presence and abundance of microbial pathogens in fresh locally produced, packaged and distributed kunun-zaki drinks. A total of 20 samples were randomly purchased from 20 vendors and hawkers. Each of the samples obtained was tenfold serially diluted using sterile peptone water. From the appropriate dilutions, 0.1ml were removed and spread plated on Salmonella-Shigella agar, Mannitol salt agar, and Eosin methylene blue agar plates. The inoculated plates were then incubated at 37°C for 24 hours. This study found that of the 20 kunun-zaki samples investigated, 70% were contaminated by Staphylococcus aureus which ranged from 1.0x104 to 1.21x105 (CFU/ml). Salmonella spp ranged from 1.2x104 to 4.1x104 (CFU/ml), and contaminated 60% of the samples. Escherichia coli ranged from 0.2x104 to 1.1x104 (CFU/ml) and was found in 45% of the samples. The result showed that the locally produced, packaged and distributed kunun-zaki drinks were highly contaminated by foodborne microbial pathogens and it makes it unsafe for human consumption. It further showed that public health is put at risk when unsafe locally produced kunun-zaki beverage is consumed; hence, local producers and Agencies saddled with the responsibility to monitor, supervise and certify food safety must strictly ensure the protection of consumers and public health by insisting that traditional methods of production, packaging and distribution of kunun-zaki drinks follow, maintain and sustain standards that guarantee quality, safety and accessibility. Consumers must resist the urge to purchase kunun-zaki drinks from unverified sources; producers, vendors and hawkers.

Comparable Expressions of Bacillus species on Different Growth Media

An investigation was carried out using Pikovskaya Broth (PKB), Luria Bertani Broth (LBB), and Peptone Water (PW) to analyse growth expressions of constructed Bacillus subtilis sub sp and compared to a commercial Bacillus subtilis RIK 1285. The aim was to determine the effect of carbon, nitrogen and other elements at different variations on the metabolic activities under different conditions. The results obtained showed growth density of 4.1 g/ml at 70oC and 3.1 g/ml at pH 6.0; 3.3 g/ml at 70oC and 2.8 g/ml at pH 6.0; 3.8 g/ml at 60oC and 2.6 g/ml at pH 7.0 from PKB, LBB and PW respectively. The growth density of the commercial strain recorded 3.8 g/ml at 50oC and 2.8 g/ml at pH 7.0; 3.1 g/ml at 50oC and 2.3 g/ml; 3.0 at 50oC and 2.3 at pH respectively. The investigation showed importance and relevance of gene metabolic upgrade on the utilization of multiple nutrients present from one media to another. Keywords: media formulation, microbial reaction, growth promoters, growth density

Antibiotic Resistance Profiling of Salmonella sp. isolated from African Catfish (Clarias gariepinus)

The African catfish (Clarias gariepinus) is an important fresh water fish consumed by a large percentage of the populace globally and it may be contaminated by pathogenic bacteria such as Salmonella sp. In this study, a total of fifteen (15) samples of African catfish were collected from different markets in Lokoja, Nigeria. The Salmonella sp. were isolated from the catfish samples by pre-enrichment in peptone water and subsequent inoculation on selective medium namely brilliant-green agar (BGA), bismuth sulphite agar (BSA) and Salmonella-Shigella agar (SSA). The Salmonella isolates were tested for susceptibility to 10 different commercially available antibiotics using the disc diffusion method. A total of thirty-four Salmonella species was isolated. The percentage occurrence of Salmonella sp. in the catfishes examined was very high (80%). The incidence of Salmonella sp. in the intestine (86.7%) of the catfish was higher than for the gills (66.7%) and the skin (73.3%). Majority of the isolates were resistant to Amoxicillin, Sulfomethoxazole-trimethoprim, Amoxicillin-clavulanic acid and Streptomycin. This study therefore demonstrated the occurrence of Salmonella species in African catfish with some exhibiting antibiotic resistance. Thus, there is a potential risk of transmission of drug resistant Salmonella species to man when contaminated catfish is consumed. The use of antibiotics in fish farming should be regulated so as to decrease antibiotic residues in fish.

Antibiogram of the predominant bacterial contaminants of Nigerian currency notes in circulation in Ogun State, Nigeria

Currency notes can act as a vehicle for the transmission of pathogenic organisms. This study was carried out to determine the antibiotic susceptibility patterns of the predominant bacterial contaminants of Nigerian currency notes in circulation in parts of Ogun State. A total of 240 naira notes of 8 different denominations were collected from various persons into sterile polythene bags, transferred into universal bottles containing 10 mL of sterile buffered peptone water. The notes were removed; the resulting solution incubated overnight and the overnight solution inoculated onto Blood agar, Mannitol salt agar, Eosin Methylene Blue agar and MacConkey agar plates and incubated at 370C for 24 hours. The isolates were then identified by Gram reactions and Biochemical tests and their susceptibility profiles against 8 commonly used antibiotics were determined. A total of 95 out of the 240 samples showed bacterial contamination and the prevalent isolates include: Escherichia coli 31 (32.6 %), Salmonella typhi 26 (27.4 %), Staphylococcus aureus 20 (21.1 %) and Bacillus subtilis 18 (18.9 %) respectively. There was no bacteria growth on the control samples. 52.3 % of the isolates were resistant strains. EC 1 isolate showed the highest susceptibility with an inhibitory zone diameter (IZD) of 25 mm against ciprofloxacin while on the whole, 26.6 % of the isolates were susceptible to all the antibiotics evaluated with 20.9 % showing intermediate susceptibility. This study showed that most of the circulating currency notes harbored one or more bacteria, especially the resistant strains which could pose a severe public health challenge

CONTAMINATION OF CHICKEN EGGSHELLS AND EGG CONTENTS WITH SALMONELLA SPECIES FROM SELECTED FARMS IN KOSGAMA, COLOMBO DISTRICT

Salmonellosis is a common, widely distributed foodborne disease. Consumption of raw or undercooked chicken eggs infected with Salmonella has been reported in association with salmonellosis cases; however, minimum attention has been paid to regulate the quality of eggs released for consumption. This study aimed to investigate the presence of Salmonella in eggs collected from selected farms from Kosgama area and to compare the egg quality of backyard and commercial farms. Randomly purchased eggs from selected chicken farms were analyzed for the presence of Salmonella. Egg content was mixed thoroughly, and 25.0mL was inoculated into 225.0mL of 1% Buffered Peptone Water (BPW) and incubated at 350C (24h). From the pre-enriched specimen, 0.1ml was added to 10.0ml of Rappaport Vassiliadis broth and incubated at 420C (24h). The same procedure was followed for shells. Isolated cultures were streaked on Brilliant Green Agar (BGA) and Xylose Lysine Deoxycholate Agar (XLD) and incubated at 350C for 24h. Colonies were investigated with Gram staining, biochemical tests and serotyping was carried out to identify the species. Of 78 eggs, 35 were from backyard and 43 from commercial farms. Six specimens (4 from shell and 2 from content) yielded Salmonella (7.69 %). Four of the positive specimens were from backyard farms (4/35, 8.91%) and remaining two (2/43, 3.62%) were from commercial farms. Isolates were identified as S. Typhimurium and S. Enteriditis. The prevalence of Salmonella was 7.69 % (n=6). The proportion of Salmonella showed no significant difference (p=0.782) between backyard and commercial farms.

Antibacterial effect of titanium dioxide with or without silver as additive on staphylococcus aureus from clinical samples

Antibiotic resistance has now become a perpetual global problem due to the emergence and reemergence of old and new multiresistant bacteria that there is a constant need of newer drugs to combat this phenomenon. Nanoparticles are now considered for their antibacterial effect and those such as Titanium dioxide have a good mechanical properties and biocompatibility, especially being non toxic to human skin and cost effective. This study was done to show the antibacterial effect of Titanium dioxide with and without Silver as addendum on Staphylococcus aureus strains from clinical samples. Staphylococcus aureus isolated from various clinical samples was inoculated onto peptone water and further inoculated onto glass slides coated with TiO2 annealed at 200C, 400C and onto TiO2 with 0.1%, 0.3%, 0.6% and 0.8% silver as additive at 1 hour intervals each. The growth was observed after 18 hours of incubation. The highest antibacterial effect was observed within 2 hours of treatment with 0.8% Ag on TiO2 nanoparticles, while it took longer with the other concentrations of silver. With TiO2 and 0.1% Ag, it took at least 7 hours of treatment for complete antibacterial effect though within the first hour itself the effect was observed. Though TiO2 nanoparticles in pure form have significant antibacterial effect, there is a considerable increase in its antibacterial effect when silver is added as an additive, with higher concentrations of Ag having more effect.