Detection of major food-borne pathogens in raw milk samples from dairy bovine and ovine herds in Iran

First detection of tick-borne encephalitis virus (TBEV) in raw milk samples in North-Western Iran

Tick-borne encephalitis virus (TBEV) is a significant cause of flaviviral infections affecting the human central nervous system, primarily transmitted through tick bites and the consumption of unpasteurized milk. This study aimed to assess the prevalence of TBEV and identify new natural foci of TBEV in livestock milk. In this cross-sectional study, unpasteurized milk samples were collected from livestock reared on farms and analysed for the presence and subtyping of TBEV using nested reverse transcription-polymerase chain reaction , alongside the detection of anti-TBEV total IgG antibodies using ELISA. The findings revealed that the highest prevalence of TBEV was observed in goat and sheep milk combined, whereas no TBEV was detected in cow milk samples. All identified strains were of the Siberian subtype. Moreover, the highest prevalence of anti-TBEV antibodies was detected in sheep milk. These results uncover new foci of TBEV in Iran, underscoring the importance of thermal processing (pasteurization) of milk prior to consumption to mitigate the risk of TBEV infection.

Genotyping and antibiotic susceptibility of Campylobacter species isolated from raw milk samples in Qazvin, Iran

OBJECTIVE

Campylobacter species are major causes of foodborne illnesses, with unpasteurized milk being a significant carrier of these bacteria, posing a public health risk. One of the challenges in managing Campylobacter infections is the emergence and spread of antibiotic resistance. We conducted a study in Qazvin, Iran, testing 84 raw cow's milk samples to determine the frequency of C. jejuni and C. coli using culture-based and multiplex PCR methods. Additionally, the disk diffusion and RAPD-PCR approaches were utilized to evaluate the phenotypic antibiotic resistance profile and genetic diversity of Campylobacter strains.

RESULTS

The findings indicated that Campylobacter spp. was present in 19.05% of the samples, with C. coli being the predominant isolate. We tested eight antibiotic agents, and the resistance levels of the isolates were as follows: erythromycin 100%, tetracycline 75%, doxycycline 56.25%, ceftriaxone 43.75%, chloramphenicol 37.5%, amoxicillin-clavulanic acid 25%, nalidixic acid 12.5%, and azithromycin 6.25%. Genetic diversity analysis categorized Campylobacter isolates into 39 clusters, indicating a wide diversity among strains. However, no significant correlation was observed between antibiotic resistance and cluster patterns. These findings underscore the role of raw milk as a reservoir for Campylobacter spp. and highlight the substantial antibiotic resistance and genetic diversity within the species population.

Campylobacter prevalence from food, animals, human and environmental samples in Iran: a systematic review and meta-analysis

BACKGROUND

Campylobacter regarded as a major cause of foodborne gastroenteritis in humans. The present study aimed to determine the prevalence of campylobacter in food, animal and human samples of Iran.

RESULTS

Quantitative synthesis was performed from 119 articles. White meat had the highest pooled prevalence of Campylobacter spp. (43.9%). Pooled prevalence of 7.9% and 5.5% for Campylobacter, respectively, were determined for red meat and eggs from Iran. Campylobacter was seen in 14.9% of environmental samples and 8.4% of human samples. In most of the samples C. jejuni had higher frequency than C. coli. Most of the isolated Campylobacter harbored several of the known virulence related genes of this pathogen.

CONCLUSION

Chicken was identified as the Campylobacter reservoir. As such preventive strategies in all stages of poultry production until consumption are necessary to control foodborne human infection with Campylobacter in Iran.

Occurrence and risk factors of brucellosis among domestic animals: an artificial neural network approach

Brucellosis is a zoonotic infectious disease with a worldwide distribution. This cross-sectional study aimed to determine the occurrence of Brucella in milk and blood samples of ruminants and the importance factors associated with animal brucellosis in Eastern Iran. A total of 200 paired samples, including blood (100) and milk (100), were obtained from the goats, sheep, and cows in Eastern Iran. Serum agglutination (SAT) and 2-mercapto ethanol (2-ME) tests were performed on the sera. A multiplex-polymerase chain reaction (m-PCR) assay was performed to identify the following species of Brucella, including B. abortus biovar 1, 2, 4, 3b, 5, 6, and 9, B. abortus S19, B. melitensis, and B. melitensis Rev.1 vaccine strain. B. abortus RB51 vaccine strain was also investigated in a second PCR assay. Risk factors for infection with Brucella spp. including the effect of abortion, contact with the wild animals, herd type, age, and previous vaccination in predicting blood contamination with B. abortus biovar 1, 2, and 4 were modeled by use of the artificial neural network. A total of 23 samples were seropositive regarding SAT and 2-ME tests. In total, B. abortus was detected in 35% and 15% of blood and milk samples, respectively, by the m-PCR assay. One sample of each of milk and blood was detected to have B. melitensis. Some samples were simultaneously contaminated with two Brucella species or two biovars of B. abortus. B. abortus S19 and B. melitensis Rev.1 vaccine strains were also detected in milk and blood samples. The sensitivity and specificity of the ANN model were 81% and 62%, respectively. In conclusion, B. abortus had higher frequency than B. melitensis in blood and milk samples. ANN determined herd type, previous vaccination, and age of the animal as the largest predictors of blood contamination with B. abortus.

Frequency of etiological agents of acute bacterial meningitis using culture and polymerase chain reaction assay

Bacterial meningitis is one of the most severe infectious diseases with high rate of morbidity and mortality in developing countries. The current study aimed to investigate the frequency of etiological agents of bacterial meningitis among patients admitted to three hospitals in Zanjan, Iran. A total of 100 cerebrospinal fluid (CSF) samples were collected aseptically, and cytochemical analysis, Gram staining, culture, and PCR were performed. Forty-six percent of CSF samples had positive bacterial culture results. However, PCR showed a higher detection rate of bacterial meningitis causing pathogens when compared with culture (52% vs. 46%; p > 0.05). Fifty-two percent of patients with bacterial meningitis were aged <1 year. The most prevalent pathogen was Streptococcus pneumoniae (36.5%), followed by Neisseria meningitidis (28.8%) and Streptococcus agalactiae (15.4%). Listeria monocytogenes was not isolated from CSF culture. The frequency of Haemophilus influenzae, L. monocytogenes and Escherichia coli was 7.7%, 1.9% and 9.6%, respectively. Although in patients aged <1 year, S. pneumonia, N. meningitidis and group B streptococcus were the most common pathogens causing meningitis, and in patients aged between 1 and 10 years, Escherichia coli was the most common. According to the results, the culture was less effective for diagnosis of bacterial meningitis than PCR. Our findings indicate that the most common causative agents of bacterial meningitis in Iran may be vaccine-preventable pathogens. Therefore, the prevention and control measures should be considered to reduce the incidence of bacterial meningitis.

Identification of Coxiella burnetii in Raw Milk of Livestock Animal in Iran

Coxiella burnetii is the causative agent of Q fever in humans and animals. This study aimed to determine the frequency of C. burnetii in milk samples of dairy animals (goats, sheep, and cattle) in some selected regions in Iran, where there is no information about prevalence of C. burnetii. In this study, 162 individual milk samples were collected from 43 farms in three provinces (Tehran, Hamadan, and Mazandaran). Real-time PCR was used for the detection of IS1111a element of C. burnetii. In total, 23 of 162 samples (14.2%, 95% confidence interval (CI): 9.65–20.2%) were positive for C. burnetii by real-time PCR. C. burnetii was detected in 10.17% (95% CI: 4.74–20.46) of goat milk samples. In sheep milk samples, 18.6% (95% CI: 9.74–32.62) were positive, and C. burnetii was detected in 15% (95% CI: 8.1–26.11) of cattle milk samples. Molecular evidence of the presence of C. burnetii was seen in milk samples of dairy animals in all the studied regions. These findings demonstrated that C. burnetii infection, especially in raw milk samples, deserves more attention from the health care system and veterinary organization in Iran.

Worldwide meta-analysis of the prevalence of Campylobacter in animal food products

The objective of this meta-analysis was to summarize available information on the prevalence of thermotolerant Campylobacter in different animal food products. A number of multilevel random-effect meta-analysis models were fitted to estimate mean prevalence of thermotolerant Campylobacter and to compare them among animal food products (cattle, pigs, broiler, hen, goat, sheep). The mean prevalence of Campylobacter spp. in animal food products was 29.6% (95% CI 27.6%-31%), and the mean prevalence of C. jejuni and C. coli were 19.3% and 9.7%, respectively. The prevalence of Campylobacter spp. was higher in products whose sources were broiler meat (p-estimate = 47.8%; 95% CI 44.9%-50.6%). C. jejuni was mainly observed in broiler meat where prevalence estimate (p-estimate) was 33.7% (95% CI 30.7%-36.8%). On the other hand, C. coli was observed in broiler meat (p-estimate = 14.1%; 95% CI 12.3%-16.1%) and sheep meat (p-estimate = 11.0%; 95% CI 3.6%-29.1%). The animal food products with the lowest prevalence of Campylobacter spp. were milk and dairy products (p-estimate = 3.5%; 95% CI 1.8%-6.5%), eggs (p-estimate = 4.0%; 95% CI 1.4%-10.7%), sausage (p-estimate = 9.4%; 95% CI 3.3%-24.0%), This meta-analysis concluding that C. jejuni is the most prevalent species worldwide and broiler meat is the main contamination source for human. The prevalence of Campylobacter species has public health importance and national authorities must monitor the situation in each country with the aim to establish the appropriate risk management measures.

The prevalence of Brucella spp. in dairy products in the Middle East region: A systematic review and meta-analysis

Brucellosis, known as Malta fever or Mediterranean fever, is one of the most common bacterial zoonotic diseases caused by Brucella spp. which can result in serious health issues. The objective of the present study was to systematically review and summarize the studies regarding the prevalence of Brucella spp. in milk and milk products in the Middle East region. Some international databases (PubMed, Web of Science, Scopus, Science Direct, and Google Scholar) were searched to retrieve relevant reports published between 1 January 2008 and 30th October 2018. After assessing for eligibility, 30 articles containing 9281 samples, were included in the current study. The highest number of publications were found in Iran and Turkey (n = 12 and 7, respectively), while Saudi Arabia, Kuwait, and Syria had the lowest number of publications (n = 1). Besides, the highest and lowest prevalence was observed in Kuwait (62%) and Egypt (15%), respectively. The highest and lowest overall prevalence of Brucella spp. in milk was found in raw cow milk 36% (95%CI: 28-54%) and raw buffalo milk 13% (95%CI: -22-48%), respectively. The overall prevalence in cheese estimated to be 9% (95%CI: -16-35%). The overall prevalence of Brucella spp. in dairy products in the Middle East was estimated to be 29% (95%CI: 23-35%). The results indicate that more risk management plans are needed to reduce the incidence of Brucella spp. in dairy products in the Middle East, especially in cow milk.

Prevalence of Coxiella burnetii in milk collected from buffalo (water buffalo) and cattle dairy farms in Northwest of Iran

The present study was conducted to determine the prevalence of C. burnetii in raw milk samples collected from water buffalos and cattle in Northwest of Iran (West Azerbaijan Province). A total number of 840 milk samples were randomly collected from buffalos and cattle belonged to three different geographical regions in west Azerbaijan (the map is necessary). The milk samples were collected seasonally during 2018 and the age of animals were recorded. All the milk samples were subjected to DNA extraction. Nested-PCR was used to detect C. burnetii based on the transposable gene IS1111. The results showed that 16.9% (95% CI: 14.5%-19.6%) of the examined milk samples (19.3% buffalo and 14.6% cattle samples) were positive for C. burnetii. There was a significant difference in C. burnetii shedding in milk between different age groups in cattle but not in buffalos (p value <0.05). The shedding of C. burnetii in milk was highly prevalent in summer (31.1%) (p < 0.05, 95% CI: 26.1%-38.4%). There were significant regional and seasonal variations in the prevalence of C. burnetii in the examined milk samples. It was concluded that buffalo population in west Azerbaijan should be considered as an important factor in the epidemiology of Q fever and consequently in public health.

Molecular prevalence of Coxiella burnetii in milk in Iran: a systematic review and meta-analysis

Q fever is a major zoonotic disease in the world. The aim of this meta-analysis was to estimate the prevalence of Coxiella burnetii in animal milk in Iran. We systematically reviewed the literature to identify eligible studies from January 2008 to June 2016 in English or Farsi (Persian) databases. We extracted the molecular prevalence of C. burnetii in milk from cows, goats, sheep, and camels in Iran. The total prevalence of C. burnetii in cow milk was 15.09% (95% CI 11.08-19.10) by PCR methods. The highest and lowest prevalence of Q fever agent were seen in the East Azerbaijan (25.55%) and Khorasan-Razavi (4.22%) provinces, respectively. The molecular prevalence of C. burnetii in goat milk was 7.80% (95% CI 3.54-12.07%). The provinces of Qom (0%) and Lorestan (44.71%) had the lowest and the highest frequency of C. burnetii infection in goat's milk, respectively. Total prevalence of C. burnetii in sheep milk was 3.79% (95% CI 0.72-6.87%). The highest frequency of C. burnetii in sheep milk was detected in the Khorasan-Razavi province (34.78%). The frequency of C. burnetii in camel milk was 1.43%. High infection of C. burnetii in milk is an important health problem in Iran, amplified by the traditional preparations of dairy products.

High prevalence and risk factors of Coxiella burnetii in milk of dairy animals with a history of abortion in Iran

Coxiella burnetii is causative agent of Q fever, which is a public health problem in most countries. The aim of this study was to study the prevalence rate of C. burnetii in raw milk of dairy animals in Iran with previous history of abortion. In this survey, milk samples were collected from different dairy animals with history of abortion from Qom province (center of Iran). Samples were tested by Nested PCR and Real-time PCR for detection of IS1111 gene of C. burnetii. In total, 34.92% (44 of 126) milk samples were positive for C. burnetii. Prevalence of C. burnetii in cattle, sheep and goat milk was 33.33%, 35.71% and 35.71%, respectively. Age was a significant risk factor for shedding of C. burnetii in cattle (P = 0.02) and goat (P = 0.05). Shedding of C. burnetii was high prevalence in milk of dairy animals with history of abortion in Iran. The high prevalence of this bacterium in milk (especially in animals with history of abortion) indicates that Excreted by milk as a potential source to spread of infection in the environment.

Epidemiology of Listeria monocytogenes prevalence in foods, animals and human origin from Iran: a systematic review and meta-analysis

Background

Listeria monocytogenes as the main causative agent of human listeriosis is an intracellular bacterium that has the capability to infect a wide range of cell types. Human listeriosis is a sporadic foodborne disease, which is epidemiologically linked with consumption of contaminated food products. Listeriosis may range from mild and self-limiting diseases in healthy people to severe systemic infections in susceptible populations. This study aimed to investigate the prevalence of L. monocytogenes in food resources and human samples from Iran.

Methods

A systematic search was performed by using electronic databases from papers that were published by Iranian authors Since January of 2000 to the end of April 2017. Then, 47 publications which met our inclusion criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software.

Results

The pooled prevalence of L. monocytogenes in human origin was 10% (95% CI: 7–12%) ranging from 0 to 28%. The prevalence of L. monocytogenes in animals was estimated at 7% (95% CI: 4–10%) ranging from 1 to 18%. Moreover, the pooled prevalence of L. monocytogenes in Iranian food samples was estimated at 4% (95% CI: 3–5%) ranging from 0 to 50%. From those 12 studies which reported the distribution of L. monocytogenes serotypes, it was concluded that 4b, 1/2a, and 1/2b were the most prevalent serotypes.

Conclusions

The prevalence of L. monocytogenes and prevalent serotypes in Iran are comparable with other parts of the world. Although the overall prevalence of human cross-contamination origin was low, awareness about the source of contamination is very important because of the higher incidence of infections in susceptible groups.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5966-8) contains supplementary material, which is available to authorized users.

Prevalence of Campylobacter jejuni and Campylobacter coli in raw milk and some dairy products

Aim:

This study was accomplished to test raw milk and certain dairy products sold in local markets of Qena, Egypt, for the presence of Campylobacter coli and Campylobacter jejuni.

Materials and Methods:

A total of 150 samples of raw milk, kareish cheese, and yoghurt (50 samples each) were subjected first to enrichment in Bolton broth at 42°C for 2 days under a microaerobic condition, subsequently campylobacter blood free selective agar plates were cultured and incubated in the same condition of the broth. Based on the morphological and biochemical themes of the growing colonies, it was further classified into Campylobacter spp. The identified isolates were later affirmed by polymerase chain reaction using primers that were designed to locate hipO genes in C. jejuni and glyA in C. coli.

Results:

Of the total 150 examined samples of raw milk and soft cheese samples; 37 (24.6%) samples were contaminated with Campylobacter spp. C. jejuni was dominating in this study in 20%, 14%, and 8% of the examined raw milk, kareish cheese, and yoghurt samples, respectively. No sample harbored C. coli.

Conclusion:

Campylobacter spp. could be detected in 24.6% of the investigated samples. C. jejuni isolated from 14% of the total tested samples, while C. coli could not be detected from the examined samples. Campylobacter spp. is rampant in the areas of poor hygienic conditions making products made from raw milk of public health hazard.