Frequency of isolation of enterotoxigenic staphylococci from milk of nursing mothers in Kaduna, Nigeria (original) (raw)

Staphylococcal Enterotoxins and Enterotoxigenic Staphylococcus aureus in Raw Milk: A Screening Study

Kocatepe Veterinary Journal, 2020

Staphylococcus aureus is one of the most important cause of foodborne intoxications in human beings. Staphylococcal enterotoxins (SEs) may lead to outbreaks because of taking food such as milk and dairy products. The aims of this study were to analyze the presence of staphylococcal enterotoxins and enterotoxigenic properties of the S. aureus isolates in 120 raw milk samples. One hundred and twenty raw milk samples were analyzed to detect SEs using the enzim-linked immunosorbent assay (ELISA) method. Staphylococcal entertoxin genes (sea, seb, sec, sed, see) were analysed by polymerase chain reaction (PCR). In the current study, SEs were found 2 of 120 bulk tank milk samples. Totally 18 (38.3%) of 69 isolates were confirmed by PCR targeting nuc and coa genes in S. aureus. SEs genes were detected as 3 (16.6 %) of 18 S. aureus isolates. Staphylococcal enterotoxins in foods like milk and dairy products are the potential public health hazards. Surveillance programs and effective monitoring systems are required for controlling staphylococcal enterotoxins in raw milk.

Staphylococcus aureus enterotoxin genes detected in milk from various livestock species in northern pastoral region of Kenya

Food Control, 2019

Staphylococcus aureus (SA) food poisoning results from consumption of preformed S. aureus enterotoxins in food. The enterotoxins are one of the most important virulence factors of the bacterium. The risk posed by contamination of milk intended for human consumption by pathogenic S. aureus in pastoral areas in Kenya is still generally not well documented yet this information is critical for ensuring safety to consumers who sometimes may take unpasteurized milk. This study, therefore determined the prevalence of S. aureus enterotoxin genes in raw milk from cattle, goats, sheep and camels intended for human consumption in northern Kenya. A total of 603 milk samples from 57 zebu cattle, 346 galla goats, 8 red Maasai and dorper sheep, 4 one-humped camel (Camelus dromedaries) and 188 pooled from all animals were collected from Isiolo and Marsabit counties of Kenya. S. aureus isolates were cultured from milk samples using a selective media, mannitol salt agar (MSA). Suspect colonies of SA were further analyzed using biochemical tests. Polymerase chain reaction and sequencing techniques were used to confirm SA and detect sea, seb, sec, sed and see enterotoxin genes. Overall, potentially pathogenic S. aureus harboring enterotoxic genes were detected in 85 (14.09%, 95% CI: 11.55-17.1%) of the total milk samples. Genes encoding enterotoxins were detected in the S. aureus bacteria isolated from the milk samples. At least one type of S. aureus enterotoxin gene (SE) was detected in 74.11% (95% CI: 63.91-82.24%) of the 85 isolates. The most frequently encountered gene in the two counties was see (51; 60%, 95% CI: 49.73-69.76%) followed by sea (22; 25.88%, 95% CI: 17.76-36.09%) and sec (19; 22.35%, 95% CI: 14.8-32.29%). None of the isolates tested positive for sed. Overall, 21 of the 85 (24.7%, 95% CI: 16.76-34.83%) strains harbored more than one enterotoxin gene. More than half of the S. aureus isolates harbored at least one of the enterotoxin coding genes, indicating milk samples contaminated by S. aureus could have a high chance of causing staphylococcal food intoxication. Consumption of raw and sour milk in the region could increase the risk of staphylococcal food poisoning and pastoral communities in the region are therefore advised to consume pasteurized milk.

Factors determining the load of Staphylococci species from raw bovine milk in Khartoum State, Khartoum North, Sudan

In this study, 644 raw milk samples were collected from various milk sources of Khartoum state during May 2003 till April 2004. Using the API kits, both coagulase positive and negative Staphylococci (CPS and CNS) were identified. Most of the CPS isolates were Staphylococcus aureus, while the majority of CNS were Staphylococcus epidermidis. 23.8% of the samples were found to be positive to both CPS and CNS while 33.7% of the samples were negative to both CPS and CNS. Forty one percent of CPS isolates was found to be S. aureus and 39% of CNS were S. epidermidis. The coagulase positive Staphylococci (CPS) were determined in 45% of the tested samples while coagulase negative Staphylococci (CNS) were found in 44.7% of them, of which 16.5% exceeded the recommended bacterial safety limits for CPS. The highest of the samples that exceeded this limit was found in vendor milk samples (19.4%) while the market milk was 18.4%.

Enterotoxin genes in coagulase-negative and coagulase-positive staphylococci isolated from bovine milk

Journal of Dairy Science, 2013

The objective of this study was to isolate and identify the main staphylococcal species causing bovine mastitis in 10 Brazilian dairy herds and study their capability to produce enterotoxins. Herds were selected based on size and use of milking technology, and farms were visited once during the study. All mammary glands of all lactating cows were screened using the California Mastitis Test (CMT) and a strip cup. A single aseptic milk sample (20 mL) was collected from all CMT-positive quarters. Identification of Staphylococcus spp. was performed using conventional microbiology, and PCR was used to determine the presence of enterotoxinencoding genes (sea, seb, sec, and sed). Of the 1,318 CMT-positive milk samples, Staphylococcus spp. were isolated from 263 (19.9%). Of these isolates, 135 (51%) were coagulase-positive staphylococci (CPS) and 128 (49%) were coagulase-negative staphylococci (CNS). Eighteen different species of CNS were isolated, among which S. warneri, S. epidermidis and S. hyicus were the most frequent. The distribution of Staphylococcus species was different among herds: S. epidermidis was found in 8 herds, S. warneri was found in 7 herds, and S. hyicus in 6 herds. Some of the CNS species (S. saprophyticus ssp. saprophyticus, S. auricularis, S. capitis, and S. chromogenes) were isolated in only one of the farms. Genes related to production of enterotoxins were found in 66% (n = 85) of all CNS and in 35% of the CPS isolates. For both CNS and CPS isolates, the most frequently identified enterotoxin genes were sea, seb, and sec; the prevalence of sea differed between CPS (9.5%) and CNS (35.1%) isolates. Staphylococcus warneri isolates showed a greater percentage of sea than seb, sec, or sed, whereas S. hyicus isolates showed a greater percentage of sea than sec. Over 60% of CNS belonged to 3 major species, which carried 62.2 to 81.3% of the enterotoxin genes. The high prevalence highlights the potential for food poisoning caused by these species. For possible high-risk situations for food poisoning, such as milk produced with total bacterial counts greater than regulatory levels and stored under inappropriate temperatures, monitoring contamination with CNS could be important to protect human health. Because the prevalence of CNS intramammary infections in dairy herds is usually high, and these species can be found in great numbers in bulk milk, identification of risk factors for production of staphylococcal enterotoxins should be considered in future studies.

Characterization of coagulase-positive Staphylococcus spp., antimicrobial resistance profile, and presence of enterotoxin-producing genes in goat milk in Paraná State

Semina: Ciências Agrárias

Goat milk presents interesting characteristics to consumers, but the production of this food faces several challenges that influence its quality. Process failures from milking to processing and commercialization can expose milk to contamination by pathogenic microorganisms, including the coagulase-positive Staphylococcus group. Although Staphylococcus aureus is the most relevant species in mastitis and food poisoning, other species in this group are also important, especially those related to food poisoning. This study aimed to identify the coagulase-positive Staphylococcus species in goat milk using biochemical tests, determine the prevalence of antimicrobial resistance using the disc diffusion test, and investigate enterotoxin-producing genes, sea, seb, sec, sed, see, seg, seh, and sei by multiplex PCR. A total of 384 coagulase-positive Staphylococcus strains obtained from raw goat milk collected from nine farms in Paraná during four seasons of the year were studied. Biochemical t...

Enterotoxigenic coagulase positive Staphylococcus in milk and milk products, lben and jben, in northern Morocco

The Journal of Infection in Developing Countries, 2009

Background: The aim of this research was to determine the prevalence of enterotoxin genes (sea-seo) in Coagulase Positive Staphylococcus (CPS) isolated from unpasteurized milk and milk products. These results were compared with the results obtained by using the detection kit SET-RPLA for the specific detection of staphylococcal enterotoxins (SEA-SED). Methodology: Eighty-one samples of milk and milk products were analyzed for the presence of Staphylococcus strains. Forty-six coagulase positive Staphylococcus isolates were tested for the production of staphylococcal enterotoxins (SEA-SED) by using the reversed passive latex agglutination method. The strains were also tested for the presence of se genes (sea-seo) by polymerase chain reaction. Results: One or more classical enterotoxin products (SEA-SED) were observed in 39% of the strains tested, while se genes were detected in 56.5%. SEA and sea were most commonly detected. For newly discovered se genes among CPS isolates tested in this study, except the seh gene which was revealed in four isolates (8.7 %), none of the strains harbored any of the other se genes (see, seg, sei, sej, sek, sel, sem, seo and sen). Conclusions: The finding of a pathogen such as staphylococci-producing SEs and containing se genes in milk and milk products in northern Morocco may indicate a problem for public health in this region. The presence of enterotoxigenic strains in food does not always necessarily mean that the toxin will be produced. For that reason, the combination of both methods (RPLA and PCR) is a guarantee for success in diagnostic analysis tests.

Contamination Level of Staphylococcus spp. in Raw Goat Milk and Associated Risk Factors

This study was aimed to investigate the presence of pathogenic bacteria in raw goat milk by using Staphylococcus spp. as indicator bacteria, and also to evaluate the potential risk factors associated with them. Information regarding potential risk factors was collected by questionnaire. The conventional bacteriological method for bacterial isolation and the indirect test (California Mastitis Test (CMT)) for determining udder inflammation status were employed. A sample size of 300 udder halves milk samples from three commercial dairy goat farms in the Bogor District, West Java Province, Indonesia were investigated for counts and prevalence of indicator bacteria. Ten potential risk factors were also evaluated in relation to counts and prevalence of indicator bacteria. The results showed that the median value of indicator bacterial count from overall udder-half milk samples was 3.00 log cfu/ml. The indicator bacterial count from udder-half milk samples was significantly different (P&lt...

Safety issues of raw milk: evaluation of bacteriological and physicochemical characteristics of human milk from a bank in a teaching hospital, focusing on Staphylococcus species

2021

Many infants are nurtured with milk supplied by human banks, whose bacteriological and physical-chemical profiles are a major issue. We investigated the bacteriological and physical-chemical characteristics, as well as genotypic and phenotypic and profiles of Staphylococcus species isolated from 240 samples of breast milk from a bank in a teaching hospital. Dornic acidity of milk revealed that 95.4% (229/240) had acceptable limits (< 8.0 oD). Caloric intake showed a wide variation in cream content (4%), fat (4%) and energy values (559.81 Kcal/L). Staphylococcus (105/186 or 56.5%) and Enterobacter (25/186 or 13.4%) were the most prevalent genera, although other microorganisms were identified, including Klebsiella pneumoniae and Pseudomonas aeruginosa. Amoxicillin/clavulanic acid (125/157 or 79.6%), vancomycin (115/157 or 73.2%), and cephalexin (112/157 or 71.3%) were the most effective antimicrobials. High resistance rates of isolates were found to penicillin G (141/157 or 89.8%),...

Assessment of exposure to staphylococcal enterotoxins genes by consumption of ready to consume milk products in milk shop outlets in Mbeya, Tanzania

African Journal of Food Science, 2019

This study assessed the exposure of humans to Staphylococcus species expressing the Enterotoxins genes (SEs) through consumption of boiled-milk-served-hot and fermented milk in Mbeya, Tanzania. A survey involving 120 consumers revealed that 67.5% of the respondents were buying raw milk from milk shops for home consumption. About 76% of respondents boiled milk before consumption, 14.8% ferment the milk after boiling and 5.8% consumed fermented milk without boiling. Children (30%) consumed milk more frequently than other members in the family. Among consumers who buy milk from the milk shops, 71% were daily consumers of both boiled milk served hot and fermented milk. Approximately, 1197 L (90% CI, 987-1416) of ready to consume milk was sold per day. Of which 860 L (90% CI, 645-1071) and 337 L (90% CI, 168-530) were boiled-milk-served-hot and fermented milk, respectively. Out of the ready to consume milk, 490 L (90% CI, 464-516) of boiled-milk-served-hot was contaminated with SEs gene compared to 77.5 L (90% CI, 67-88) of fermented milk. Daily 2394 people were consumers of milk and their products. Exposure assessment shows that the probability of consuming boiled-milk-served-hot and fermented milk contaminated with SEs gene at a milk shop was 0.42 (90% CI, 0.071-0.838) and 0.17 (90% CI, 0-0.62), respectively. It was estimated that every day, 363 (90% CI, 341-385) and 58 (90% CI, 49-66) people were likely to consume boiled milk taken hot and fermented milk contaminated with SE gene, respectively. The finding shows that exposure to SEs gene was two times more likely to occur in people who consume boiled-milk-served-hot than in people who consume fermented milk (OR. 2.221 (90% CI, 0.6-6.16). Awareness creation on proper food handling among milk handlers to reduce contamination along the milk value chain is recommended.

AENSI Journals Advances in Environmental Biology Subclinical mastitis on the raw milk as a risk factor for the transmission of Staphylococcus.aureus and coagulase-negative staphylococci, multidrug resistance in Sidi

In Algeria, the milk is consumed directly, generally in the raw state thus escaping any quality control. The subclinical mastitis becomes a problem of food security. Our hypothesis is that consumption of the raw milk of the cows with subclinical mastitis is a tool for transmission of antibiotic resistant staphylococci, which can pass unobserved to man. A total of 981 raw milk samples were obtained from 250 cow's quarters. The California Mastitis test (CMT) has been performed to diagnose the presence of subclinical mastitis. Milk samples were subjected to a bacteriological study and presumptive colonies were confirmed by biochemical characterization using the API-Staph-20 system. The sensitivity tests were performed by disc diffusion method on Muller-Hinton agar, for 13 antibiotics commonly used in veterinary medicine in Algeria, and the VITEK 2 system is used for the determination of the minimum inhibitory concentrations (MIC) for the strains confirmed as S. aureus. The biochemical identification showed that 73.75% of the isolates are CoNS, and that 26.25% are S.aureus. Resistance to penicillin G touches 61.02% of the strains of CoNS that with the tetracycline is of 74.58%. For S. aureus, we found a high resistance to penicillin G 80.95% and with the tetracycline 71.43%. According to our results, 02 (9.52%) isolate is S. aureus resistant to the methicillin , with modified penicillin-binding proteins , identified by the test of the disk of the oxacillin with a diameter of: R≤10 mm, and confirmed by one MIC ≥ 4 µg / l. The MIC of the vancomycin has proved that one strain is a VRSA with one MIC ≥ 32 µg / ml, and a second strain is a hetero-VISA with one MIC ˃ 1 µg / ml. We noted that for the 21 strains of S. aureus, 11 different phenotypes of resistances dominated by resistance to "penicillin G". Our results indicated that there's a multi-resistant staphylococci passage in raw milk consumed in the western region of Algeria, harmful for the health and the security of the consumer, with a higher prevalence of coagulase negative staphylococci compared with S.aureus. Despite unknown pathogenicity of the species, organisms may be the tanks of the resistant to antibiotics; which requires periodic monitoring of antimicrobial resistance of staphylococci in order to control their spread.