Bismuth Sulfite Agar Research Articles

Prevalence of Non-typhoidal Salmonella Species in Food and Stool Samples in Port Harcourt, Rivers State, Nigeria

Aim: To assess the prevalence of Non-Typhoidal Salmonella spp isolated from food and stool samples in Port Harcourt. Study Design: This was a cross-sectional study with simple randomized sampling. Methodology: In this study, 210 stool samples and 210 food samples collected from December 2022 to November 2023 were tested for Salmonella using standard bacteriological and biochemical tests. The Salmonella species were isolated from the samples using Salmonella-Shigella agar (SSA), and Bismuth Sulfite Agar (BSA) after pre-enrichment and enrichment methods had been carried out using peptone water and Selenite F Broth after which biochemical tests were carried out for further identification. Data collected was analyzed with Graph pad prism version 8. Results: The prevalence and distribution of Salmonella were presented in frequencies and percentages with all analysis done at a 95% confidence interval and P-values less than .05 were considered significant. From chi-square analysis there was a 3.3% prevalence rate in food samples in comparison to stool samples that had a 2.4% prevalence (P value = .56). A higher prevalence was also reported in the female subjects (3.7%) compared to the male subjects (1.0%) (P value = .19). There was a statistically significant difference in relation to the age groups with the ‘above 50’ and ‘0 – 10’ age groups having a higher prevalence (11.1% and 10% respectively) compared to other age groups (P value = .02). For the food samples, samples in the chicken category had the highest prevalence (8.7%) (P value = 0.11). Conclusion: This study reports a relatively lower prevalence of Non-Typhoidal Salmonella species at 2.9% with the age, education and occupation of the subjects being significantly associated (P value < .05) with the prevalence of the infection. Health promotion and appropriate surveillance system should be put in place to continually reduce the burden of this disease.

Spread of Multi-drug Resistant Aerosolised Salmonella sp and Escherichiacoli from Dumpsites in Built Environment of Abraka Town, Nigeria

Waste dumpsites are known to be hot spots for the development of multi-drug resistant (MDR) pathogenic microorganisms, which can be dispersed via aerosols. The dispersal of MDR Salmonella sp and E. coli in dumpsite-infested neighbourhoods of Abraka, a university town, was therefore investigated. Eosine Methylene Blue and Bismuth Sulphite agar plates were used to isolate airborne E. coli and Salmonella sp, respectively using settling plate technique. Air sampling was carried out at 3 neighbourhood dumpsites and at intervals of 50m up to 200m away from the dumpsites along the cardinal directions. The isolates were tested for antibiotics resistance using 10 antibiotics and those with multiple antibiotics resistance (MAR) index≥0.3 were considered MDR and subsequently subjected to plasmid curing, and re-tested for antibiotics resistance. The population of both organisms varied with cardinal directions and dumpsites, but generally declined as the distance from dumpsites increased (E. coli, 2.96-1.72 log cfu/m3 ; Salmonella sp, 2.65-0.00 cfu/m3 ). By overall assessment, mean MAR index for E. coli isolates was 0.39±0.01-0.64±0.04 and 0.37±0.02-0.68±0.03 for Salmonella sp isolates. MDR E. coli and Salmonella sp constituted 26.7-45.7 and 0.0-47.1% of the total population, respectively; and were encountered up to 200m away from the dumpsites at all directions although with decreasing numbers. There were significant reductions (P<0.05) in the MAR indexes of both organisms after curing thereby indicating plasmid involvement in the MDR. In conclusion, the aerosolised plasmid-encoded and chromosome-based genes in MDR organisms from dumpsites can be dispersed in neighbourhoods; and plasmids can spread antibiotics resistant genes by horizontal transfer and compound therapeutic options

Microbial carriage of Dermanyssus gallinae ticks

The effectiveness of the development of the poultry industry depends on the veterinary well-being of farms, in particular, in relation to invasive diseases. One of the most widespread ectoparasites among poultry farms is the gamasic mite Dermanyssus gallinae. As a result of tick parasitism, the egg and meat productivity of chickens decreases, often the death of young birds. Dermanyssus ticks are hematophagous and can be carriers of pathogens of infectious diseases of chickens, including zooanthroponosis. The research method was used to investigate the presence of specific pathogens carried by Dermanyssus gallinae. In laboratory conditions, inoculation was carried out from the homogenate of ticks isolated from chickens and objects of poultry premises on nutrient media (blood agar, yolk-salt agar, Saburo, Simmons, Endo, Ploskirev, bismuth-sulfite agar). As a result of bacteriological studies of Dermanyssus gallinae isolated from different substrates, microorganisms belonging to three species and four genera were isolated – Staphylococcus spp., Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli. Dermanyssus ticks isolated from chickens were carriers of only two genera and one species of microorganisms – Staphylococcus spp. (37.5 %) and Euterococcus facalis (31.3 %). Moreover, monoisolates (77.8 %) were most often isolated from ticks, the majority of which were Staphylococcus spp. (44.5 %), less – Enterococcus faecalis (33.3 %). Bacterial associations were rarely identified (22.2 %). Dermanyssus ticks, isolated from the objects of the poultry house environment, turned out to be carriers of a larger spectrum of microorganisms, where Staphylococcus spp. were more often isolated (100 %) and Escherichia coli (43.8 %), less often – Klebsiella pneumoniae (37.5 %) and Enterococcus faecalis (18.8 %). The isolates were dominated by associations of microorganisms (62.5 %). The monoisolate was represented only by Staphylococcus spp. (37.5 %). The data obtained by us regarding the isolated microorganisms further expand the vector role of D. gallinae, proving their danger for poultry enterprises producing food products. In general, dermanyssiosis can seriously affect the health of chickens both because of ectoparasites – hematophages, and because of the ability to transmit pathogens.

Deteksi Bakteri Gram-Negatif Pada Permukaan Daun Kemangi (Ocimum basilicum) dari Tiga Pasar Tradisional di Bogor

Ocimum basilicum or basil is commonly consumed raw by Indonesian. However, it is easily contaminated by pathogenic bacteria. This study aimed to detect Gram-negative bacteria in basil leaves obtained from three traditional markets in Bogor. Isolation and quantification of bacteria using serial dilution showed that the average number of bacteria on the surface of basil leaves was 9.6 × 107 CFU/g. Basil leaves obtained from the second traditional market had the highest number of bacteria, namely 11.3 × 107 CFU/g. All isolated bacteria have the same morphology namely bacilli, then further purified and characterized physiologically. The nine bacterial isolates obtained were able to grow on selective-differential media including Salmonella-Shigella agar (SSA), bismuth sulphite agar (BSA), and eosin-methylen blue (EMBA). Gram staining showed that all bacterial isolates were classified as Gram-negative bacteria. The hemolytic ability of bacterial isolates was tested using blood agar base media, three out of nine bacterial isolates were able to produce hemolysin. Molecular identification based on 16S rRNA sequences showed that the bacterial isolates belonged to the Providencia sp., Proteus sp., Pseudomonas sp., and Kluyvera sp. groups.

Combination of the electronic nose with microbiology as a tool for rapid detection of Salmonella

Salmonella is one of the most important foodborne pathogens and its analysis in raw and processed products is mandatory in the food industry. Although microbiological analysis is the standard practice for Salmonella determination, these assays are commonly laborious and time-consuming, thus, alternative techniques based on easy operation, few manipulation steps, low cost, and reduced time are desirable. In this paper, we demonstrate the use of an e-nose based on ionogel composites (ionic liquid + gelatine + Fe3O4 particles) as a complementary tool for the conventional microbiological detection of Salmonella. We used the proposed methodology for differentiating Salmonella from Escherichia coli, Pseudomonas fluorescens, Pseudomonas aeruginosa, and Staphylococcus aureus in nonselective medium: pre-enrichment in brain heart infusion (BHI) (incubation at 35 °C, 24 h) and enrichment in tryptone soy agar (TSA) (incubation at 35 °C, 24 h), whereas Salmonella differentiation from E. coli and P. fluorescens was also evaluated in selective media, bismuth sulfite agar (BSA), xylose lysine deoxycholate agar (XLD), and brilliant green agar (BGA) (incubation at 35 °C, 24 h). The obtained data were compared by principal component analysis (PCA) and different machine learning algorithms: multilayer perceptron (MLP), linear discriminant analysis (LDA), instance-based (IBk), and Logistic Model Trees (LMT). For the nonselective media, under optimized conditions, taking merged data of BHI + TSA (total incubation time of 48 h), an accuracy of 85% was obtained with MLP, LDA, and LMT, while five separated clusters were presented in PCA, each cluster corresponding to a bacterium. In addition, for evaluation of the e-nose for discrimination of Salmonella using selective media, considering the combination of BSA + XLD and total incubation of 72 h, the PCA showed three separated and well-defined clusters corresponding to Salmonella, E. coli, and P. fluorescens, and an accuracy of 100% was obtained for all classifiers.

Cultural, morphological and biochemical properties of Salmonella typhimurium indicator bacteria used in the Ames test and their applicability for the assessment of the test system quality

Introduction. The Ames test has been widely used to study the mutagenicity of chemicals. In view of the implementation of a quality management system in the test facilities, the cultural, morphological and biochemical properties of strains used in the Salmonella/microsome test system were studied. An assessment of their applicability as additional characteristics of quality of the tester strain was made.
 Materials and methods. The study of cultural and morphological characteristics of S. typhimurium strains was carried out using the commercial media. 
 The biochemical properties of S. typhimurium cultures were evaluated using a Vitek-2 system.
 Results. Studies have shown that the procedure of marker verification for confirming the reference properties of tester strains, in addition to evaluation of the spontaneous mutation level and phenotypic characteristics (-his phenotype, the presence or absence of the R-factor plasmids, rfa- and ∆uvrB mutations), can be extended by periodically assessing their biochemical properties. Most of the biochemical characteristics of bacteria of the Salmonella typhimurium serovar are inherent for tester strains. Compared to the wild-type bacteria atypical features of tester strains are a negative reaction in the hydrogen sulfide production test, positive activity of tyrosine arylamidase, the ability to utilize 5-keto-D-gluconate, unstable activity of alpha-galactosidase. Differential selective media used to maintain wild-type Salmonella cultures are not universal for the growth of strains of the Salmonella/microsome test system. When choosing media for cytotoxicity, survival, or sterility assessment, it is necessary to take into consideration the growth characteristics of the Salmonella tester strains on different media: the ability to grow on selective media decreases in the series of Endo-agar > Salmonella Shigella -agar > Bismuth-sulfite agar > Ploskirev’s agar.
 Limitations. The research is limited to the study of cultural, morphological and biochemical characteristics of S. typhimurium, but not Escherichia coli.
 Conclusion. The described cultural and morphological properties of tested strains on different media can be used to assess cytotoxicity/survival of treated cultures performing studies according to OECD 471. The use of additional biochemical markers of authenticity and morphological properties of tester strains will help to ensure the quality of studies using the Ames test in the processes of conservation, reproduction, and routine testing.

Determination of Total Microbial Bioload and Pathogen Testing from Bakery Products

Bakery products are the most widely consumed food on the planet. Microbiological spoilage is one of the most common reasons for bakery products having a short shelf life. This study reports on isolation of microorganisms from bakery products. The study aimed to prospect the isolation of bacteria, total colony count and pathogen testing were carried out nutrient agar media and specific media. Isolation of bacteria was done using nutrient agar medium, total colony count was prosecuted by colony counting method and pathogen testing was performed using specific media like mannitol salt agar, EMB agar, cetrimide agar and bismuth sulphite agar. Biochemical characterization was executed for the obtained pathogen. It was preceded by test like indol test, MRVP test, simmon’s citrate test, catalase test, gelatinase test and TSI test. After completion of these tests it was concluded the obtained microorganism was Salmonella species.

Биологические, биохимические и серологические особенности сальмонеллеза в пчелиных хозяйствах Масаллинского района (Азербайджан)

The article presents the issues of studying the biological, biochemical and serological features of bee salmonellosis in bee farms of Azerbaijan in the years 2018 and 2019. Sick bees with clinical signs were examined. In order to study the biological, biochemical and serological features of bee salmonellosis, a diagnostic study of bees was conducted (drip agglutination reaction and serological reactions). On the meat-peptone agar, small transparent colonies with a soft bluish tinge appear on the 2-3 day. The isolation of bacteria from the intestine, hemolymph and pectoral muscles with subsequent crops was studied on meat-peptone broth (MPB), agar (MPA) and bismuth sulfite agar.

Study of the effectiveness of the use of closed-type UV-recirculators for air disinfection in enclosed space

Introduction. The research is devoted to assessing the results of our studies of indoor air concerning microbial contamination during the operation of a UV recirculator with different modes (different UV doses). Also, a theoretical calculation of the influence of the ratio of the capacity of the UV recirculator to the air volume of the treated room on the efficiency of air disinfection has been made. Materials and methods. The study of indoor air in terms of total bacterial count (TBC), including coccal microflora and yeast and mould fungi, were carried out. Air sampling and evaluation were carried out under the requirements of Methodical guidelines MUK 4.2.2942-11 “Methods of sanitary and bacteriological studies of environmental objects, air and sterility control in medical institutions”. The evaluation of the results was carried out following R 3.5.1904-04, "The use of ultraviolet bactericidal radiation for disinfection of indoor air". During the study, agar culture media were used: Sabouraud agar, yolk-salt agar (YSA), meat-peptone agar (MPA), nutrient agar with the addition of 5% sheep blood (blood agar), bismuth sulfite agar, XLD-agar, cetrimide-agar, “Shine” agar, Endo agar. Results. As a result of the studies carried out, it was shown that a dose of UV irradiation of the order of 12-15 mJ/cm2 leads to an insignificant change in the concentration of bacteria (TBC) and fungi in the air (the efficiency was 58% and 69%, respectively). UV doses of the order of 25-30 mJ/cm2 significantly reduce the concentration of bacteria (TBC) and fungi in the air (efficiency was 99.99% and 99.4%, respectively). A theoretical calculation showed that it is practical to use a UV recirculator of such a capacity that provides an air exchange rate in the room of at least 4 (with ventilation operating at a rate of at least 2). Conclusion. To effectively use UV recirculators in enclosed spaces against bacteria and fungi, it is necessary to use models that provide a UV dose of at least 25-30 mJ/cm2. In contrast, their air capacity should provide an air exchange rate of at least 4.

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.

Abundance of Multiple-Antibiotic-Resistant Salmonella Strains in Fecal Samples of Rhinoceros unicornis of the Kaziranga National Park, India

Aims: This study was undertaken to assess the abundance of multiple-antibiotic-resistant (MAR) Salmonella strains in fecal samples of Rhinoceros unicornis of the Kaziranga National Park (KNP), India.
 Study Design: Antibiotic-resistance profile of the Salmonella isolates from fecal samples of rhinoceros was carried out by replica plating on Muller Hinton Agar (MHA) plates containing antibiotics. The presence of class 1 integrons in metallo-β-lactamase (MBL) producing Salmonella isolates was determined by multiplex PCR.
 Place and Duration of Study: The study was carried out on rhinos of KNP situated in the Golaghat district of Assam, India in April 2015.
 Methodology: Fresh rhino fecal samples (designated as 1R, 2R, 3R, 4R and 5R) were dilution plated onto MacConkey agar. Purified bacterial colonies were then streaked separately on bismuth sulphite (BS) agar plates. All black colonies which are characteric growth of Salmonella were selected and used to make master plates on Luria Agar. To determine the antibiotic-resistance profile of the isolates, master-plates of purified single colonies of Salmonella spp. were replicate-printed on plates containing antibiotics from the β-lactam, aminoglycoside, or quinolone groups. To detect the presence of an integron, a conserved segment polymerase chain reaction was used.
 Results: 97.6% of the Salmonella isolates tested were resistant to >1 antibiotics (multidrug resistant or MAR). A total of 100 isolates from two fecal samples, 4R and 5R, were found to be imipenem resistant; 52 of them tested positive for the presence of MBLs. Five of the twenty MBL producing strains contained class 1 integrons.
 Conclusion: Because Salmonella is usually spread by drinking contaminated water, it is likely that water bodies in KNP are contaminated with MAR Salmonella strains. In case of Salmonellosis outbreak among Indian one-horned rhinos, our antibiogram will assist the veterinarians to choose the appropriate regimen of antibiotics for the rhinos in the KNP.

Chemical and Microbiological Properties of Kefir Produced by Kefir Grains in Raw and Pasteurized Cow’s Milk

The traditional production of kefir uses raw milk as a fermentation substrate which is not acceptable due to food safety issues. However, kefir grains were reported to have antimicrobial properties. Hence, this study determined if kefir grains inhibited certain spoilage and pathogenic microorganisms by comparing the chemical and microbiological properties of the initial substrates: raw milk (RM) and pasteurized milk (PM) to the final products: raw milk kefir (RMK) and pasteurized milk kefir (PMK). Both final products had a significant decrease in fat, moisture, and pH, and a significant increase in protein, total solids, and titratable acidity than RM and PM, respectively. Total solids, titratable acidity, pH, total alcohol, and ethanol were significantly higher in PMK than RMK. RMK had a significantly lower coliform count than RM while both RMK and PMK had significantly higher lactic acid bacteria, yeast and mold count than RM and PM, respectively. Kefir grains’ microbial inhibiting activity was examined if plates were positive or negative against spoilage and pathogenic microorganisms. Escherichia coli-positive plates in Levine’s eosin methylene blue agar decreased in RMK. Salmonella spp.-positive plates in bismuth sulphite agar (BSA), Hektoen enteric agar, and xylose lysine deoxycholate agar decreased in RMK and PMK except for RMK in BSA. Staphylococcus aureus-positive plates in Baird-Parker agar decreased in RMK. RMK and PMK attained the kefir’s standard values for the chemical composition, lactic acid bacteria, yeast and mold count. Nonetheless, the mere presence of spoilage and pathogenic microorganisms in the final products made it unsafe for consumption.

High concentrations of pathogenic Salmonella spp. during the wet season on bathing beaches in Makassar City, Indonesia

Pathogenic bacteria in coastal areas have been found to contribute to the outbreak of acute infections among tourists, and can be transmitted through contact with polluted recreational water. Salmonella spp. are bacteria frequently associated with waterborne diseases, they can cause various symptoms from mild gastroenteritis to death. This research aimed to determine the concentration of Salmonella in bathing beaches and to evaluate whether the concentrations could be harmful to human health. Samples were collected for the analysis of bacteria and water quality at six different bathing beach sites in Makassar, Indonesia. Salmonella analysis was conducted using a membrane filtration method, where the filter was then placed on Bismuth Sulphite Agar (BSA), a selective medium for Salmonella growth. Salmonella identification was based on a suite of biochemical reaction tests. Salmonella concentration per membrane was determined using a colony counter. Salmonella concentrations were compared between sites using one-way ANOVA with post hoc test, while the correlation between Salmonella concentrations and water quality was evaluated using Principal Component Analysis (PCA). Three colony types grew on the BSA. Salmonella were detected at all six bathing beaches in Makassar. Salmonella concentrations were highest in Tanjung Bayang Beach, followed by Akkarena Beach, Kayangan Island, Lae-lae, Samalona Island, and Bulo Gading Beach. Salmonella concentration correlated with high total organic matter levels, and exceeded the EEC standard for recreational swimming and bathing water at all six bathing beaches in Makassar.

Isolation of Enteric Bacteria from Various Sources in Selected Poultry Farms in Kaduna State

This study was designed to isolate enteric bacteria from various sources in selected poultry farms in Kaduna state. One hundred and fifty samples of poultry feed, water and droppings from five poultry farms in Kafanchan, Zaria, Gonin-gora, Kamazou and Ungwan Television were examined for the presence of enteric bacteria. 30 samples were collected from each farm and were analysed using spread plate method. The culture media used were Selenite Feaces (SF) broth) and Bismuth sulphite agar. The contaminants isolated include Escherichia coli, Salmonella spp and Proteus mirabilis. The distribution of the isolates based on sample type were droppings (1.33%) and feed (2.67%). There was no significant difference in each of the samples (p>0.05). The percentage distribution of isolates based on location were: Kafanchan (0.00%), Zaria (0.00%), Kamazou (33.33%) for Salmonella and (16.67%) for Proteus mirabilis, Gonin-gora (50%), and Television (0.00%). The results showed that the poultry feeds and droppings from the poultry farms visited in Kaduna, Nigeria had bacteria contaminants. The presence of these bacteria may be a serious health concern as these organisms are involved in causing various diseases. Therefore, hygienic measures should be taken in processing and handling of the poultry products being sold to general public. The national and local health authorities should enforce the food hygiene regulations to reduce the spread of diseases caused by these enteric bacteria. Public enlightenment programmes on the modes of transmission of Salmonella, E. coli and P. mirabilis should be conducted by Human and Veterinary Public Health services. Further studies should be conducted to know the extent of distribution of these organisms in different areas of Kaduna State and the country at large.

Variation in Salmonella typhi Infection Among Local Populations in Southern Benue, Nigeria

Background: Typhoid fever caused by Salmonella typhi is endemic in many developing countries. Objective: This study aimed to investigate the prevalence of S. typhi in patients attending secondary health centers within the 9 local government areas (LGAs) of Benue. Materials and Methods: A total of 1022 stool samples, from 583 (57.0%) males and 439 (43.0%) females were collected from patients diagnosed using Widal reaction between August 2016 and July 2017. Selenite broth, Salmonella-Shigella agar, Xylose Lysine Deoxycholate agar and Bismuth Sulfite agar were used for isolation. S. typhi was identified using cultural and biochemical characteristics. Univariate analysis and multivariate logistic regression were performed to analyze the collated data. Results: A high prevalence of S. typhi (43.7%, n = 447) and significant differences were observed (P < 0.05) in the study site, age, sex and month of sampling. Oju LGA accounted for the highest rate, 64.2% (n = 123). S. typhi infection was highest in patients aged ≤10 years (52.7%, n = 243). Males had a significantly higher isolation frequency of 46.8% (adjusted odds ratio [AOR] = 1.321, CI = 1.027–1.700) than females (39.6%). Isolation rates were higher between January (50.0%, n = 31) and May (61.8%, n = 76). Some Widal positive samples were negative for S. typhi upon culturing. Conclusion: These findings suggest the existence of a significant public health hazard which can negatively affect the livelihood of rural dwellers. There is a need for a review of the approach to the diagnoses of typhoid fever in the study area. Increased efforts at sanitation and personal hygiene are advocated.

LACTOSE FERMENTING SALMONELLA TYPHIMURIUM, SALMONELLA STRATFORD AND SALMONELLA BLEGDAM

the general concept that lactose fermenting Salmonella (lac+ Salmonella) are rare may be correct; however, these strains can become endemic in a given geographic area. Failure to detect these strains presents a public health problem.This study report cases of lactose fermenting Salmonella Typhimurium (4 isolates), Salmonella Stratford (2 isolates) isolated from diarrheic calves and S.Blegdam (one isolate) isolated from diseased chicken. The strains are strong lactose fermenter and resemble Escherichia coli on primary plating media and in triple sugar iron agar. The aim of this study was to compare the capacity of 4 different selective media:- Xylose Lysine Deoxycholate agar (XLD), novobiocin – brilliant green – glucose agar (NBG), modified semisolid Rappaport –Vassiliadis agar (MSRV) and Bismuth sulphite agar (BS) to detect the growth of lactose fermenting S. Typhimurium, S. Stratford and S.Blegdam inoculated in milk replacer. They were cultured, in parallel, on these media, both by direct cultivation and after selective enrichment in selenite broth. The performance of BS was the excellent medium of all media used followed by XLD in combination with lysine iron agar (LIA). On MSRV only two strains grew and only one produced swarming. On NBG after 48h in the cases where there was growth, the number of colonies was much lower and the rest were inhibited. Antibiotic sensitivity pattern differed between lactose -positive Salmonella isolates and lactose-negative Salmonella Typhimurium standard strain ATCC 14028. Lactose-positive strains showed a higher degree of resistance than lactose-negative strain. The differences in resistance were seen in the case of erythromycin, chloramphenicol, streptomycin and tetracycline.

Evaluation of Selective-Enrichment and Chromogenic Media for Salmonella Detection in Raw Shell Egg Contents with a Low Microbial Load.

The current study was conducted to evaluate the ability to recover Salmonella from shell egg contents by culture methods. A total of 4,000 eggs were obtained from a grading and packing center located in the Gyeonggi Province of South Korea, and 200 samples were created by pooling 20 broken eggs. The pooled samples were held at room temperature for 4 d before a 25-mL aliquot of each pool was added to 225 mL of modified trypticase soy broth (mTSB) and incubated at 35°C for 24 ± 2 h. A loopful of the culture was streaked onto chromogenic Druggan-Forsythe-Iversen (DFI) agar and incubated at 36 ± 1°C for 18-24 h. In addition, 1 mL and/or 0.1 mL of the mTSB cultures were added to 10 mL of Muller-Kauffmann tetrathionate with novobiocin (MKTTn) or Rappaport-Vassiliadis (RV) broth, and they were incubated for 24 ± 2 h at 35 ± 2°C or 42 ± 0.2°C, respectively. A loopful from these cultures was streaked onto Brilliant Green (BG), xylose lysine deoxycholate (XLD), and bismuth sulfite (BS) agar plates, respectively. Directly streaking onto DFI agar revealed the presence of Salmonella in 14 out of the 200 pooled samples (7%); whereas the combination of RV medium and BG, XLD, and BS agar detected the pathogen in only 9 (4.5%), 7 (3.5%), and 3 (1.5%) of the pooled samples, respectively. When MKTTn broth was used, Salmonella was detected in 7 (3.5%), 2 (1%), and 0 (0%) of the samples when streaked onto BG, XLD, and BS agar, respectively. The results indicate that direct plating onto DFI agar without enrichment was the most suitable among the methods evaluated in this study for detecting Salmonella in raw shell egg contents with a low microbial load.

Effects of organic acids to prolong the shelf-life and improve the microbial quality of fresh cut broccoli florets

This study was conducted to evaluate the effectiveness of a combination of specific organic acids for disinfecting fresh cut broccoli floret samples contaminated with Listeria monocytogenes serotype 1/2b and Salmonella enterica serovar Typhimurium. In addition, the effects of organic acids on the microbial load of broccoli samples during storage at +4 °C were determined for 7 days. The organic acids tested were acetic, benzoic, sorbic, fumaric, malic, tartaric, lactic and succinic acids and the concentrations used were 1 and 2% (w/v and v/v). L. monocytogenes and S. Typhimurium were grown on the selective media before the contamination. The broccoli samples were dipped first into the pathogen solutions containing L. monocytogenes and S. Typhimurium, then into the organic acids and subsequently counted on Oxford agar and bismuth sulphite agar, respectively. The broccoli samples dipped into the organic acids without pathogen culture were also investigated in terms of total mesophilic aerobic microorganisms,...

English

Bloodstream infections remain public health problem and have resulted to morbidity and mortality in HIV/AIDS patients. This study was therefore aimed at determining the prevalence of bacteremia in HIV infected patients on highly active anti-retroviral therapy (HAART) attending Federal Medical Centre, Ido-Ekiti, Ekiti State. A total of 105 blood samples were cultured using brain heart infusion and subcultured on bismuth sulphite agar, MacConkey agar and chocolate agar. Isolates were identified using cultural and biochemical characterization. Antibiotic susceptibility test was done using disc diffusion method. The prevalence of bloodstream infection in HIV infected patients on HAART was found to be 22.9% and they were having the CD4+ T-cell counts of <300 cells/µl. There were five males and 19 females that had bloodstream bacterial infection. A total number of 24 isolates were recovered with Escherichia coli being the most prevalent bacterial isolates 12(50.0%), followed by Staphylococcus aureus, 8 (33.3%) and Streptococcus pneumoniae, 4 (16.7%). The antibiotic susceptibility test revealed a high level of resistance with highest resistance seen in Cotrimoxazole (87.5%), followed by ciprofloaxcin (83.3%), ampicillin (79.2%), levofloxacin (62.5%) while ceftazidime, ceftriaxone and gentamycin (54.2% each) showed the least resistance. The overall percentage of antibiotics resistance of the 7 selected antibiotics tested against isolated bacterial had 71.4, 67.9 and 66.1% resistance for S. pneumonia, Escherichia coli and S. aureus, respectively. However, the prevalence of bloodstream infection among HIV patients on HAART in Ekiti was relatively high and resistance to cephalosporins drugs was lower as compared to fluoroquinolones. Therefore, cephalosporin group of antibiotics is recommended for the treatment of bacteria bloodstream infection in HIV/AIDS patients. Key words: Bacteremia, human immunodeficiency virus (HIV), antibiotics resistance, Nigeria.

&lt;span lang="EN-GB" style="font-size: 12.0pt; font-family: Times New Roman"&gt; The Survey of Microbial Quality of the Dry Sample, Extract and Brewing of some Medicinal Plants &lt;/span&gt;&lt;/p&gt;

Medicinal plants may be exposed to a wide range of microbial contamination during pre- and post- harvest stages and they can present high microbial counts. In this study, the microbial quality of 44 samples of dry herbs namely: mint (Menthaspp.), lemon balm (Melissa officinalis), summer savory (Satureja hortensis), zataria (Zataria multiflora), Indian valerian (Valeriana wallichii), their brewing and extracts were analyzed. Total count using plate count agar medium (PCA), coliform count by Violet Red Bile Agar (VRBL), Enterobacteriacea by Violet Red Bile Glucose (VRBG) were evaluated. Medium Baird-Parker agar (BP) medium and Tryptone Bile X-Gluc (TBX) medium were used for the isolation and enumeration of Staphylococcus aurous and E. coli spp. respectively. Furthermore, Xylose Lysine Deoxycholate agar medium (XLD) and Bismuth Sulfite Agar medium(BSA) were used for detection of Salmonella spp. Fungal and mold contamination was assessed using yeast extract glucose chloramphenicol agar. The results showed that the contamination of the samples with total count (100%) and Enterobacteriaceae (85%), total coliform (83%), mold and yeast (98%) and E. coli ssp. (2.27) were detected, including in the study samples the absence of pathogenic bacteria like Staphylococcus aurous, Salmonella spp. Moreover, the extract had a lower microbial load in comparison to dry herb samples. Also, the lowest and the highest of contamination rates were observed for Indian valerian and zataria, respectively. According to the results, there is a need to control the environmental conditions and improve hygiene in the production process; even more, it is recommended to choose a suitable decontamination method for disinfection during packing medicinal plants and during post-packing manipulation and transport.