Coagulase-positive Staphylococci Research Articles

Sanitary Surveillance Program for pools in Matosinhos, Portugal

Abstract The use of pools for sports, recreational, and therapeutic activities has increased over time. It is important to ensure and control the quality of the water and surrounding areas, as well as the hygienic-sanitary conditions of these spaces. The ‘2018 Pool Sanitary Surveillance Program’ of the Portuguese Northern Regional Health Administration proposes the surveillance of water quality, teaching accessories, and surfaces. The aim of this investigation is to conduct microbiological analysis of the teaching accessories and surfaces in public pools in the municipality of Matosinhos and assess if this program has improved the results for water quality, teaching accessories, and surfaces from 2018 to 2023. The environmental health team of our Public Health Unit performed swabs of the teaching accessories and surfaces of all seven public pools in Matosinhos for microbiological analysis. The swabs were performed in 2018 (21), 2019 (48) and 2023 (42). During each visit, three random points were selected for analysis. In 2019, 31 rugs (64,6%) were analysed, but in 2023 only 10 (23,8%) were rugs. It was found that rugs had the highest contamination by P. aeruginosa (94,4%), fungi (60,8%), and the only sample with coagulase-positive Staphylococci. There was a decrease in samples from twelve to six with P. aeruginosa and an increase from 22 (46.8%) to 29 (69.0%) with fungi from 2019 to 2023. Bacterial colonies grew in 20 samples (95.2%) in 2018, 44 (91,6%) in 2019, and 42 (100%) in 2023. All water samples collected for the evaluation of microbiological parameters outlined obtained compliant results. Fungal and P. aeruginosa detection indicate a potential risk to the health of pool users. A quality report with corrective measures was produce for each pool in each visit. Surveillance of pool water, teaching materials and surrounding surfaces, is crucial to ensure water quality and safety. By doing so, we may lower the risk of disease transmission and protect the population’s health. Key messages • To ensure the safety of pool users is a public health challenge. It would be relevant to have legislation that addresses this issue. • To survey pools and its surroundings and accessories must be a continuous task, allied with literacy to management and users.

Performance Characteristics of the Quantitative Method for Staphylococcus aureus in Food Products Correspond to ISO 16140-3: 2021

Staphylococcus aureus is a pathogenic bacterium that poses significant health risks when present in food products. High levels of Staphylococcus aureus in food can indicate poor hygiene and handling practices during food production, processing, or storage. In order to maintain food safety and quality, verification of the quantitative method of Staphylococcus aureus is very important. Method verification represents a crucial stage in guaranteeing that all employed procedures conform to the necessary criteria for dependable and precise data. Following the guidelines established in ISO 16140-3:2021, method verification is accomplished through the calculation of the Intralaboratory Reproducibility Standard Deviation (SIR) for implementation validation and the eBias value for verifying the suitability of the method for assessing specific food items. This research was conducted with the objective of confirming the ISO 6888-1:2021 as the designated reference method for quantifying Staphylococcus aureus in food products. For the purpose of confirming the implementation of the method, Cheese was utilized as the test food item. In the context of verifying the method's applicability to different food products, a range of items including condensed milk, margarine, baby porridge, cassava chips and ready-to-eat sausage were examined as challenging foods. Every chosen food item was artificially contaminated with Staphylococcus aureus WDCM 00034. The SIR value obtained was 0.04 ≤ 2× 0.11 (the lowest mean of SR value from ISO 6888-1:2021) which indicated that the National Quality Control Laboratory of Drug and Food (NQCLDF), Indonesian FDA was able to implement the method very well. In addition, the eBias value for all types of food tested was below 0.5log10, which showed that the quantitative method for coagulase-positive Staphylococci (Staphylococcus aureus and other types) could be applied in the NQCLDF laboratory for the extensive scope of food.

Increased incidence of methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis in the skin and nasal carriage among healthcare workers and inanimate hospital surfaces after the COVID-19 pandemic.

Healthcare workers in hospitals are exposed to infectious diseases that occur in the hospital making them a source of infection for the patients. It is interfaced as cross-contamination agents for MRSA and MR-CoNS, and preventive measures need to be adapted accordingly. The study aimed to assess Methicillin-Resistant Staphylococcus (MRS) on the skin and nasal cavities of healthcare workers (HCWs) and identifying isolates to the species level. Swab samples were cultured on mannitol salt agar (MSA) to obtain MRS and determine their ability to produce coagulase. Their susceptibility to antibiotics were determined by agar screening and disk diffusion methods and further identification was done at the species level. The highest percentage of methicillin resistant coagulase positive Staphylococci (MRCoPS) was reported among skins of male HCWs, (71.4%) were identified as MRSA. The highest levels of methicillin resistant coagulase negative Staphylococci (MRCoNS) were mainly detected in both nasal cavities, (75%) were identified as MRSE. MRSA was reported from doctors (p-value 0.033), whereas the highest incidence of MRSE was obtained from the nurses (p-value 0.048). This study highlighted that incidence of MRSA was mainly detected in doctors and MRCoNS in both nasal cavities. The highest percentage of MRCoNS was recovered from the patients' room followed by the reception table. Moreover, vancomycin is suggested to be highly effective in managing and controlling S. aureus, MRSA- and MRSE related infections.

A comprehensive study on the autochthonous microbiota, volatilome, physico-chemical, and morpho-textural features of Montenegrin Njeguški cheese

The present study aims to deepen the knowledge of the microbiota, gross composition, physico-chemical and morpho-textural features, biogenic amines content and volatilome of Njeguški cheese, one of the most popular indigenous cheeses produced in Montenegro. Cheese samples were collected in duplicate from three different batches produced by three Montenegrin artisan producers. For the first time, the microbiota of Njeguški cheese was investigated using both culture-dependent techniques and metagenomic analysis. Coagulase positive staphylococci viable counts were below the detection limit of the analysis (<1 log cfu g−1). Salmonella spp., Listeria monocytogenes and staphylococcal enterotoxins were absent. However, relatively high viable counts of Enterobacteriaceae, Escherichia coli, Pseudomonadaceae and eumycetes were detected. Metataxonomic analysis revealed a core microbiome composed of Lactococcus lactis, Streptococcus thermophilus, Debaryomyces hansenii, and Kluyveromyces marxianus. Furthermore, the detection of opportunistic pathogenic yeasts such as Magnusiomyces capitatus and Wickerhamiella pararugosa, along with the variable content of biogenic amines, suggests the need for increased attention to hygienic conditions during Njeguški cheese production. Significant variability was observed in humidity (ranging from 38.37 to 45.58 %), salt content (ranging from 0.70 to 1.78 %), proteins content (ranging from 21.42 to 25.08 %), ash content (ranging from 2.97 to 4.05 %), hardness, springiness, and color among samples from different producers. Gas chromatography-mass spectrometry analysis showed a well-defined and complex volatilome profile of the Njeguški cheese, with alcohols (ethanol, isoamyl alcohol, phenetyl alcol), esters and acetates (ethyl acetate, ethyl butanoate, isoamyl acetate), ketones (acetoin, 2-butanone), and acids (acetic, butanoic, hexanoic acids) being the main chemical groups involved in aroma formation. This research will provide new insights into the still poorly explored identity of Njeguški cheese, thus serving as a first baseline for future studies aimed at protecting its tradition.

A foodborne outbreak caused by staphylococcal enterotoxins in cheese sandwiches in northern Italy

Staphylococcus aureus can produce numerous toxins, including staphylococcal enterotoxins, namely, SEs, SEA to SEE, SEG to SEI, and SER to SET. They have demonstrated emetic activity and can cause food poisoning outbreaks (FBOs). Here, we report a multidisciplinary investigation conducted by authorities competent in food safety in collaboration with veterinary and health and hygiene services. The issue was foodborne intoxication which involved eight members (aged 12–74 years) of the same family. Notification reported that time to symptom onset was about 3 hours after lunch, which suggests that the food contained preformed toxins. Ham and cheese used for the preparation of sandwiches consumed by all symptomatic relatives were suspected to be the source of FBO. The day after symptoms appeared, samples were collected at the restaurant and delivered to the food safety laboratory. All analyses performed on official food samples are validated according to ISO 17025:2017 and accredited. The cheese subsamples were all positive for coagulase-positive staphylococci CPS (range: 1.1*103 CFU/g to 8.1*103 CFU/g). The pooled sample tested positive for staphylococcal enterotoxin D (SED) at 0.649 ng/g. This concentration can cause symptoms of FBO. Following the notification of suspected food poisoning, a rapid response by the district food safety agency is necessary. In the case described here, the multidisciplinary collaboration facilitated the collection of samples at the food business plant aimed at identifying a suspected source of intoxication and to withdraw unsafe food from the market.

Маститы – проблема безопасности, качества и сыропригодности молока сырого

Bovine mastitis is a common hygiene-related issue in milk production. It increases the somatic cell count in milk. Somatic cell count is an important indirect indicator of milk quality. Somatic cells include those of udder and blood. Normally, one healthy udder lobe secretes ≤ 500,000 somatic cells per 1 cm3 milk. In the presence of pathogenic bacteria, the same amount indicates a latent infection. Inflammatory processes in the udder include impaired secretion and mastitis. They increase the number of leukocytes and other blood cells in the total somatic cell count, which means that the milk came from sick cows. Raw milk for cheese production must contain ≤ 4×105 cells per 1 cm3. Mastitis, or garget milk is not suitable for cheese production. Staphylococcus aureus is the most common causative agent of staphylococcal mastitis in cows. Coagulase-positive staphylococci are responsible for 30-50% cases of infectious mastitis. They pose great risks for bulk-formed cheeses. Mastitis affects milk processing, taste, and storage capacity. It is high in chlorides and low in lactose, which gives it a flat and salty-bitter taste. If somatic cell count exceeds 5×105 cells per 1 cm3, the resulting milk has poor thermal stability. As the content of somatic cells in milk increases, so does the rennet coagulation time: fat goes into whey and moisture in curd increases, which eventually reduces cheese yield.

Evaluation of symbiotic relationships of oral microorganisms and their effect on the development of inflammatory changes of the oral mucosa in the complete absence of teeth

Introduction. By fixing on the exposed surfaces of complete removable dentures and oral soft tissues, bacteria form a biofilm, thereby increasing their overall virulence and resistance. The microorganisms that make up the biofilm are often in a symbiotic relationship, which allows them to increase their pathogenic potential and cause the development of denture stomatitis. Accordingly, when a particular strain is present in the oral cavity, the risks of symbiosis are significantly increased. The aim of the study was to evaluate the effect of symbiotic relationships of oral bacteria on the development of inflammatory changes in the oral cavity in the absence of teeth. Materials and methods. Two groups of patients belonging to the elderly age according to WHO systematization (60–74 years) with complete absence of teeth (K08.1) were formed, differing in the presence of clinical manifestations of inflammation (82 men and 49 women). Biological material sampled from the oral cavity of patients was studied using the culture method and RT-PCR. To quantify the interaction between members of the microbiocenosis, we used the Jaccard similarity coefficient. Results. Coagulase-negative and coagulase-positive staphylococci, Neisseria, Candida spp., Enterobacterales and F. nucleatum were more frequently found in patients with complete absence of teeth. Expressed symbiotic relations between microorganisms of the Enterobacterales order, Lactobacillus, Neisseria and Corynebacterium genera, as well as S. salivarius, C. albicans, F. nucleatum were established. The nature of these relations depended on the presence of inflammatory changes in the oral mucosa and, in turn, influenced the development of the latter. Thus, in the absence of inflammation, Corynebacterium, Lactobacillus and S. salivarius showed stable synergism. In case of inflammation, the association between these bacteria was accompanied by the introduction of F. nucleatum and displacement of S. salivarius. Conclusion. Thus, conditionally pathogenic microorganisms, forming microbial associations with multidirectional symbiotic relations increase their virulence, which allows them to occupy free niches in the oral cavity and subsequently trigger the development of pathological process of inflammatory character of prosthetic bed tissues.

Virulence and host specificity of staphylococci from Staphylococcus intermedius group of pigeon origin with an emphasis on Staphylococcus intermedius

The Staphylococcus intermedius group (SIG) includes coagulase-positive staphylococci commonly found in animals. The taxonomic classification within the SIG has evolved with molecular techniques distinguishing five species. Despite their similarities, these species exhibit varied host affinities, with unclear implications for virulence and host interaction.This study aimed to investigate the presence of coagulase-positive staphylococci in pigeons and to detect genes encoding for selected virulence factors in isolated strains. Another goal was to determine the adhesion capabilities of randomly selected pigeon S. intermedius, S. delphini, and canine S. pseudintermedius strains to canine and pigeon corneocytes and their adhesion and invasion abilities to canine keratinocytes in vitro.In total, 121 coagulase-positive strains were isolated from domestic and feral pigeons. The most prevalent species were S. delphini B and S. intermedius in domestic and feral pigeons, respectively. We proved that pigeon strains carried genes encoding for exfoliative toxin SIET and leukotoxin Luk-I. Moreover, we found that S. intermedius showed higher adherence to pigeon than to canine corneocytes, aligning with its presumed natural host. No difference in adherence abilities of S. pseudintermedius to canine and pigeon corneocytes was observed. In this study, we also observed that S. pseudintermedius could successfully invade the canine keratinocytes, in contrary to S. delphini and S. intermedius. Moreover, only S. intermedius was not able to invade canine keratinocytes at all.These findings highlight the complex interplay between SIG bacteria, and their hosts, underscoring the need for further research to understand the mechanisms of host adaptation and pathogenicity within this group.

Infections in Children with Acute Lymphoblastic Leukemia.

Background and Objectives: Infections are the most common and potentially life-threatening complications of the treatment of children with acute lymphoblastic leukemia (ALL). The aim of this study was to determine epidemiological, clinical, and microbiological characteristics of infections in pediatric patients with ALL. Materials and Methods: Twenty-three children (16 males and 7 females, with a mean age of 5.9 years (range of 1.3 to 12.2 years)) with ALL, treated at the Division of Hematology, Oncology, and Clinical Genetics, Department of Pediatrics, Clinical Hospital Center Rijeka, Croatia, from 1 January 2015 to 31 December 2020, were included in the study. Results: One hundred and four infectious episodes (IEs) were reported (an average of 4.5 IE per patient). IEs were more frequent in the intensive phases of antileukemic treatment. Neutropenia was present in 48 IEs (46.2%) with a duration greater than 7 days in 28 IEs (58.3%). The respiratory tract was the most common infection site (48.1%). We documented 49 bacterial (47.1%), 4 viral (3.9%), 4 fungal (3.9%), and 10 mixed isolates (9.6%), while in 37 IEs (35.6%), a pathogen was not isolated. The most common causes of bacteremia were coagulase-positive staphylococci. The most frequent empirical therapy was third- and fourth-generation cephalosporins, followed by piperacillin/tazobactam. The modification of first-line antimicrobial therapy was performed in 56.9% of IEs. Granulocyte-colony stimulating factor was administered in 53.8% of IEs, and intravenous immunoglobulins were administered in 62.5% of IEs. One patient required admission to the intensive care unit. No infection-related mortality was reported. Conclusions: ALL patients have frequent IEs. Close monitoring, the identification of risk factors, the rapid empirical use of antibiotics in febrile neutropenia, and the timely modification of antimicrobial therapy play key roles in reducing infection-related morbidity and mortality in children with ALL.

The microbial contaminants of plant-based meat analogues from the retail market

The aim of the study was to analyse the key microbial contaminants of plant-based meat analogues (PBMA) from retail. A total of 43 samples of PBMAs (12 frozen/31 chilled) in the “ready-to-cook” category, such as hamburgers, meatballs or breaded imitation steaks were purchased in retail stores in the Czech Republic in summer (n = 21) and autumn 2022 (n = 22). The detected indicator bacteria (total viable count, lactic acid bacteria, Enterobacteriaceae, yeasts, moulds) had relatively low values in the analysed PBMA samples and only rarely reached levels of 7 log CFU/g. E. coli, STEC and coagulase-positive staphylococci were not detected by isolation from plates in any of analysed samples. Mannitol positive Bacillus spp. were isolated from almost half of the analysed samples of the PBMA. B. cereus sensu lato was isolated from 3 samples by isolation from plates, and after enrichment in 35 samples (81 %). Clostridium perfringens could not be detected by isolation from plates, nevertheless after multiplication, it was detected in 21 % of samples. Analyses of PBMA samples revealed considerable variability in microbial quality. The presence of spore-forming bacteria with the potential to cause foodborne diseases is alarming. However, to evaluate the risks, further research focused on the possibilities of growth under different conditions of culinary treatment and preservation is needed.

ETIOPATHOGENETIC REASONING OF URETHRAL MICROBIOTA REHABILITATION IN PATIENTS WITH ACUTE INFECTIOUS URETHRITIS

The microbiota of the male genitourinary tract is a complex dynamic system that has not been sufficiently studied. Unlike the microbiome of the female urethral mucosa, which is constantly changing, the taxonomic composition and population level of the male urethral microbiome is more stable and independent of age. The aim of the study. To improve the results of treatment of patients with inflammatory processes of the urethra by determining the taxonomic composition, population level and microscopic indicators of the "macroorganism-microbiome" ecosystem of the microbiota of the urethra in men with acute urethritis.Material and methods. The taxonomic composition and population level of the first portion of urine of 69 sexually mature men (average age 34.8±7.14 years) with acute infectious (nonspecific) urethritis were investigated. Isolation of conditionally pathogenic bacteria was carried out by the bacteriological method using optimal nutrient media, their pH, temperature and cultivation time for each taxon. The identification of isolated pure cultures was carried out according to morphological, tinctorial, cultural, biochemical properties, as well as signs of pathogenicity and antigenic structure. To determine the mechanisms of colonization of the mucous membrane of the urethra by conditionally pathogenic microorganisms, the microecological method was used.Research results. According to the taxonomic composition and the level of microecological indicators of the "macroorganism-microbiome" ecosystem of the urethra microbiota (Margalef's species richness index, Whittaker's species diversity index, and Simpson's and Berger-Parker's species dominance indices), vulgar (common), hemolytic, and enteropathogenic Escherichia coli, coagulase-positive staphylococcus. The leading role in the formation of urethritis is played by ordinary enterobacteria - E. coli, a slightly smaller etiological role in the formation of urethritis in men belongs to S. aureus (less by 17.83%), E. coli Hly+ (less by 28.35%), enteropathogenic Escherichia coli (by 83.12%). Other microorganisms have a minimal etiological role. Conclusions. Acute urethritis in men is a polyetiological disease. Enterobacteria E. coli, E. coli Hly+, enteropathogenic Escherichia coli, K. pneumoniae, S. aureus, S. epidermidis, S. viridans are involved in the formation of the inflammatory process of the urethra. The leading causative agents of acute urethritis in men are E. coli, S. aureus, E. coli Hly+, enteropathogenic escherichia, which belong to uropathogenic escherichia.

Modeling the effects of ripening at refrigeration and ambient temperatures on physic-chemical and microbiological parameters of artisanal Minas cheese

This study aimed to assess the effects of ripening at refrigeration and ambient temperatures on physic-chemical and microbiological parameters of artisanal Minas cheeses (made from raw milk) and to model the kinetics of lactic acid bacteria – LAB, Escherichia coli – Ec, and coagulase-positive staphylococci – Sa along the ripening. Cheese pH, acidity, and moisture, fat, and protein contents were quantified, as well as LAB, Ec, and Sa concentrations. Richards and simplified Lotka-Volterra models were used to describe the microbial kinetic data. The fits were assessed by statistical indices, and the Monte-Carlo method was applied to identifiability analysis. Cheese moisture was reduced along the ripening, increasing protein concentration and acidity values. Cheese pH showed a reduction followed by an increase. LAB concentration increased to the stationary phase after a few days; Ec and Sa concentrations increased and then decreased due to interactions with LAB and low moisture content. Mathematical models successfully described the kinetics of LAB, Ec, and Sa in cheese throughout ripening. Most parameters were not correlated to each other and were estimated with narrow confidence intervals.

New Insights into Molecular Characterization, Antimicrobial Resistance and Virulence Factors of Methicillin-Sensitive Coagulase-Positive Staphylococcus spp. from Dogs with Pyoderma and Otitis Externa

The first Tunisian national molecular survey of coagulase-positive staphylococci (CoPS) isolated from dogs with pyoderma and otitis externa was conducted to evaluate the prevalence of CoPS and identify its phenotypic and genotypic diversities. A total of 99 out of the 195 samples collected from 39 sick dogs were identified across multiple sites as methicillin-susceptible CoPS belonging to the species S. pseudintermedius (64.4%), S. aureus (20.2%), S. coagulans (10.1%), and S. hyicus (5%). Fifteen sampled dogs carried more than one Staphylococcus species. Their antibiotic resistance and virulence factors were determined using conventional and molecular methods. Of the S. pseudintermedius isolates found, 17.4% were multidrug-resistant, whereas high rates of virulence genes were observed among the S. aureus isolates. On polystyrene surfaces, 75% of S. aureus isolates were biofilm producers, of which 15% were classified as strong producers. The capsular polysaccharide cap8 genotype was predominant among them. A MultiLocus Sequence Typing (MLST) analysis clustered the S.aureus isolates into five distinct sequence types (STs), with four assigned for the first time. Our findings highlight the spread of CoPS among diseased dogs and, especially, the emergence of S. hyicus, S. coagulans, multidrug-resistant S. pseudintermedius and S. aureus isolates with high genetic variability. The precise characterization of these strains, as well as their continuous monitoring, is necessary for the implementation of preventive strategies given the significant public health risk.

Assessing microbiological and heavy metal pollution in surface waters associated with potential human health risk assessment at fish ingestion exposure

Fish represent a significant source of nutrients but also cause negative health effects due to their bioaccumulation capacity for pollutants. The aim of this study was to examine the transfer of metals from the water of several rivers (Somes, Tisa, Sasar, Lapus, Lăpusel) to fish (Caras sp) tissue (subcutaneous fat, muscles, liver, intestines, kidneys, gills, brain, and eyes) and to identify and assess the carcinogenic and non-carcinogenic health risks of Arsenic (As), Cadmium (Cd), Nickel (Ni), Manganese (Mn), Cooper (Cu), Lead (Pb), Chromium (Cr) and Zinc (Zn) through the ingestion of fish (muscles and subcutaneous fat tissues). The obtained results indicated that a diet consisting of fish is particularly vulnerable, particularly in children compared to adults. The risk assessment results were below the threshold limit, although the fish samples contained heavy metals, with values exceeding the permitted limits of Fe (4.41–1604 mg/kg), Cr (727–4155 µg/kg), Zn (4.72–147 mg/kg), and Ni (333–2194 µg/kg). The studied surface waters are characterized by low and high degrees of pollution with heavy metals, as indicated by the heavy metal pollution index scores (HPI: 12.4–86.4) and the heavy metal evaluation index scores (HEI: 1.06–17.6). The considerable pollution levels are attributed to the high Mn content (0.61–49.7 µg/kg), which exceeded the limit up to fifty times. A consistent set of physico-chemical analysis (pH, electrical conductivity, total hardness, turbidity, chloride, sulphate, nitrate, nitrite, ammonium, Ca, Mg, Na, K) was analysed in water samples as well. Considering the water quality index scores (WQI: 16.0–25.2), the surface waters exhibited good quality. Microbiological results indicated the presence of Listeria monocytogenes and atypical colonies of coagulase-positive staphylococcus in fish. In contrast, the surface waters from which fish samples were collected were positive for Escherichia coli, and coliform bacteria intestinal Enterococci. Based on the study’s results, it is recommended to exercise caution in the case of children related to the consumption of fish and using the waters for drinking purposes. This study provides important data of considerable novelty to the riparian population, researchers, and even policy makers on the quality status and potential levels of contamination of river waters, fish and the bioaccumulation of heavy metals in fish that may cause adverse effects on human health if consumed, and similarly the heavy metal pollution degree of waters and the non-carcinogenic risk of heavy metals through ingestion and skin absorption of water in children and adults (the study area is a significant source of fisheries).

Comparative Antimicrobial Resistance and Prevalence of Methicillin Resistance in Coagulase-Positive Staphylococci from Conventional and Organic Dairy Farms in South Korea.

Bovine mastitis (BM) has caused huge economic and financial losses in the dairy industry worldwide, with Staphylococcus aureus as one of its major pathogens. BM treatment still relies on antibiotics and its extensive use often generates methicillin-resistant S. aureus (MRSA) and mupirocin-resistant S. aureus (MuRSA). This study compared the antimicrobial resistance trend in coagulase-positive Stapholococci (CoPS) isolated from BM milk in conventional and organic dairy farms and checked prevalence of MRSA and MuRSA. A total of 163 presumptive Staphylococci were isolated, wherein 11 out of 74 from 4 conventional farms (CF1, CF2, CF3, CF4) and 17 out of 89 from 3 organic farms (OF1, OF2, OF3) exhibited coagulase activity. Multiplex-PCR amplification confirmed at least one coagulase-positive isolate from CF1, CF2, CF3, CF4, and OF1 as S. aureus, denoted by the presence of the nuc gene. Three isolates from CF2 contained the mecA gene, indicating MRSA prevalence, while the MuRSA gene marker, mupA, was not detected in any of the isolates. Antimicrobial testing showed that conventional farm isolates were more resistant to antibiotics, especially ampicillin and tetracycline. This suggests a risk of developing multidrug resistance in dairy farms if antibiotic use is not properly and strictly monitored and regulated.

Avaliação microbiológica de carne bovina comercializadas no Brasil e conhecimentos de consumidores sobre segurança de alimentos

Meat is highly perishable and is often associated with foodborne disease outbreaks. The risk associated with handling food at home is underestimated, as consumers generally associate foodborne disease outbreaks with food from food services. This study aimed to quantify Escherichia coli, coagulase-positive staphylococci, mesophilic aerobic bacteria, and Salmonella spp. in ground beef samples sold at commercial establishments in Pelotas, Rio Grande do Sul State, Brazil, and to evaluate the knowledge of food safety among consumers in the region. Microbiological analyses were performed on 70 ground beef samples, and the knowledge of 92 meat consumers was analyzed using an online questionnaire based on the World Health Organization (WHO) safe food guidelines. Fifty percent of the meat samples had aerobic mesophilic microorganism counts above the limit established by Brazilian legislation, indicating unacceptable food quality. Only two samples (2.86%) had counts of coagulase-positive staphylococci above those allowed by legislation. The consumer knowledge regarding food safety showed that items related to “cook thoroughly” and “keeping food at safe temperatures” had the lowest percentage of correct answers. Dissemination of information about temperatures that ensure food safety is essential for consumers, especially considering that even with high levels of contamination, most microorganisms are destroyed by heat.

Four-Year Bacteriological Profile and Antibiotic Resistance Rate of Neonatal Blood Cultures in a Major Neonatal Intensive Care Unit (NICU) in Shiraz, Southwest Iran

Background: Bacterial infections are the leading cause of death in newborns. The growing resistance of bacteria to antibiotics is a major concern. In this study, we identified isolates from blood cultures in the neonatal intensive care unit (NICU) of a major referral hospital in Shiraz in southwest Iran and determined antibiotic resistance patterns. Methods: All newborns admitted to the NICU were evaluated in a four-year study. The blood samples were cultured using a BACTEC system. From May 2015 to March 2020, 5937 blood culture samples were analyzed. The antibacterial sensitivity test was conducted using the disk diffusion method, following the guidelines of Clinical &amp; Laboratory Standards Institute (CLSI) 2018. Results: In this study, 507 isolates were obtained from 5937 specimens. The most commonly isolated gram-negative bacteria were Acinetobacter (8.7%), Escherichia coli (5.7%), Klebsiella (1.6%), Enterobacter (1.4%), and Pseudomonas (0.9%). Among the gram-positive bacteria, coagulase-positive staphylococci (51.1%), coagulase-negative staphylococci (15.4%), Staphylococcus epidermidis (10.2%), non-hemolytic streptococci (2.4%), alpha-hemolytic streptococci (1.4%), and Streptococcus pneumonia (1.3%) were the most frequently isolated bacteria. Of the 318 Staphylococcus aureus isolates, 88.5% were resistant to methicillin. Conclusion: Staphylococcus, with a high frequency in the NICU, can be an alarm for medical centers. Also, in dead infants, the most observed bacterial infection was Acinetobacter infection, which requires the serious attention of the hospital infection control unit.

Microbiological quality of ready-to-eat street foods in Lisbon, Portugal

Street food sector is an important component of the food distribution system in many cities. However, foods exposed for sale on the roadside are generally associated with conditions that favors its potential microbiological contamination. In this study, the microbiological quality of 118 ready-to-eat street foods sold in the metropolitan area of Lisbon, Portugal was evaluated. Mesophilic aerobic bacteria, yeasts, moulds, Enterobacteriaceae and Escherichia coli were used as spoilage/hygiene indicators. Listeria monocytogenes, Salmonella spp., coagulase-positive staphylococci (CPS), Clostridium perfringens, Bacillus cereus and E. coli pathotypes implicated in gastrointestinal disease were used as food safety/hygiene indicators. Thirty-five (29.7%) of the samples were classified as satisfactory, 29 (24.6%) as questionable and 51 (43.2%) as unsatisfactory. Three samples (2.6%) were unsatisfactory/ potentially dangerous, due to the presence of the L. monocytogenes > 102 cfu/g and/or B. cereus > 105 and/or CPS > 104. B. cereus genes encoding causative toxins were detected in the strains isolated from two samples containing > 105 cfu/g. Salmonella spp., Clostridium perfringens and pathogenic E. coli were not detected in any of the examined samples. CPS was detected in 26.3% of the samples.A significant relationship between microbiological quality and food groups, with the increase of questionable and unsatisfactory classifications for those samples including raw components, like fruits and vegetables, was observed (Fisher-Freeman-Halton = 29.01, p < 0.001). The obtained data highlights for the need of education and training of street-food vendors to improve the food safety management system in the place of sale.

Mozzarella cheese in Italy: Characteristics and occurrence of Listeria monocytogenes and coagulase-positive staphylococci at retail

Mozzarella cheese is a popular type of fresh cheese, originating from Mediterranean countries and worldwide consumed. As for other soft cheeses, its characteristics might support the growth of Listeria monocytogenes; therefore, the research's aim was to determine the occurrence of L. monocytogenes strains and Listeria spp. on mozzarella cheese at the time of purchase (T0) and at the end of shelf life (Tf). Given the relevance in dairy products, occurrence of coagulase-positive staphylococci was also explored. Retail batches (n = 106) collected in Italy, in supermarkets, discounts and small retailers, were analysed for pH and to detect L. monocytogenes, other Listeria spp. and coagulase-positive staphylococci. Three batches were positive for L. monocytogenes (2.8%; 3/106) and nine (9/106) for other species of Listeria spp. with an occurrence of 10.4% for Listeria spp. Coagulase-positive staphylococci were never detected. Mozzarella cheese showed variability in terms of pH (from 4.30 to 6.24 at T0) and residual shelf life (from 3 to 22 days). This research confirms that L. monocytogenes can be found in mozzarella cheese at retail. However, a low concentration of the pathogen (below the limit of quantification of 10 cfu g−1) was found in the contaminated products at the time of purchase and/or at the end of shelf life. This evidence is relevant since mozzarella cheese is not undergoing further treatment before consumption therefore thus represent the level of contamination to which the consumer might be exposed. Considering the technological steps of mozzarella production, preventing food contamination in food-processing and retail-handling environments is crucial to reduce the level of exposure to the consumer.

The influence of different forms of black cumin (Nigella sativa L.) on the characteristics of sheep’s curd cheese

The influence of different forms of Nigella sativa (seeds, powder, alcoholic extract, and oil) on the traditional sheep curd was investigated by comparison with a control simple curd considering a series of sensorial, physical–chemical, and microbiological aspects. The analysis was performed on curds freshly prepared and after 10 days of refrigeration. The sensory analysis of the curds was performed using a variety of methods such as scaling method, the method of quality describing, the method of ordering by rank, “triangle” method, and “duo-trio” method. The analyzed curds were assessed and classified according to their sensory characteristics and typicality. The N. sativa supplementing of the sheep curds improved their physical–chemical characteristics by raising the fat content with 0.88–2.82% and decreasing the titratable acidity with 1.42–2.32% compared to the control curd without additive. After 10 days of refrigeration, the titratable acidity increased with 1.58–3.25% and moisture decreased (8.43–13.17%). The microbiological quality of the curd samples was influenced by the addition of black cumin in different forms, with variations in the total number of bacteria (TNB) between 4.33 and 4.39 log CFU/g compared to the control sample 5.03 log CFU/g, Enterobacteriaceae (2.53–2.58 log CFU/g) compared to the control sample 2.60 log CFU/g, and coagulase-positive staphylococci (CPS) 2.30–2.68 log CFU/g compared to the control sample 2.75 log CFU/g. After 10 days of refrigeration, the number of microorganisms decreased, TNB (4.13–4.31 log CFU/g), Enterobacteriaceae (2.34–2.53 log CFU/g), and CPS (2.02–2.55 log CFU/g), while for the control sample the values increased. The most obvious antimicrobial effect was observed in the case of the cold-pressed oil addition (1%), followed by the alcoholic extract (1%), seeds (3%), and powder (3%).