Occurrence of Methicillin-Resistant Staphylococcus spp. on Brazilian Dairy Farms that Produce Unpasteurized Cheese

RAPD-PCR-Based Fingerprinting Method as a Tool for Epidemiological Analysis of Trueperella pyogenes Infections

In this study, a Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) method for genetic typing of Trueperella pyogenes, an opportunistic bacterial pathogen, was designed. The method optimization was performed for 37 clinical T. pyogenes strains isolated from various infections in different animal species. Optimal conditions for reliable and reproducible DNA fingerprinting were determined according to the modified Taguchi method. The developed method was assessed regarding its typeability, reproducibility, and discriminatory power using the Hunter’s and Gatsons’ index of discrimination. A high degree of genetic diversity was shown between the studied strains, which represented 31 genotypes. The generated RAPD profiles were relatively complex and simultaneously easy to interpret due to the wide size range of amplicons. The discriminatory index of the designed method was sufficiently high; thus, only strains epidemiologically related displayed identical RAPD genotypes. In conclusion, the DNA fingerprinting of T. pyogenes by the developed RAPD-PCR method is a reliable typing tool that may allow a better understanding of the epidemiology as well as pathogenesis of infections caused by this pathogen.

Antimicrobial Resistance of Staphylococcus sp. Isolated from Cheeses

Simple Summary

As far as it is known, studies dealing with antimicrobial resistance in certain species of staphylococci, in particular, S. chromogenes and S. simulans, isolated from products made from unpasteurized milk are limited. In addition to that, little attention was paid to the resistance of staphylococcal isolates from regional sheep and goat cheeses. At this level, works are published that focus on the evaluation of resistance from only one sheep product, Bryndza. Other studies are only focused on the evaluation of resistance from raw sheep’s or goat’s milk. The study contributes to the knowledge of the possible spread of antimicrobial resistance from the farm to the final consumer in this area.

Abstract

S. aureus and some species of coagulase-negative staphylococci, including S. chromogenes and S. simulans, commonly cause intramammary infections. However, little attention was paid to the antimicrobial resistance of these species with respect to their occurrence in dairy products, for example, popular sheep and goat cheeses made from unpasteurized milk. The aim of this study was to investigate such sheep and goat cheeses for the occurrence and antimicrobial resistance of the relevant staphylococci species. The staphylococcal isolates were identified by polymerase chain reaction (130 isolates) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. The most common species of S. aureus (56 isolates) were identified, as well as S. chromogenes (16 isolates) and S. simulans (10 isolates). Antimicrobial resistance to penicillin, oxacilin, ceftaroline, teicoplanin, gentamicin, erythromycin, tetracycline and ofloxacin was subsequently determined in these species using the agar dilution method. The highest resistance was confirmed in all species, especially to penicillin (91%) and erythromycin (67%). The highest sensitivity was confirmed to ofloxacin (83%). Due to the high incidence of penicillin and oxacilin-resistant staphylococci, the mecA gene was detected by polymerase chain reaction, which was confirmed only in S. aureus isolates (19%). Our study shows that the tested strains (77%) were resistant to more than one antibiotic at a time.

Draft Genome Sequences of Five Staphylococcus saprophyticus Strains Isolated from African Fermented Nono in Nigeria

Five Staphylococcus saprophyticus strains were isolated from the fermented milk product nono in Nigeria and were sequenced using an Illumina MiSeq platform. The genome sizes ranged from 2.53 to 2.60 Mbp, while the GC contents ranged from 32.99 to 33.07 mol%. The genomes possessed 2,505 to 2,687 protein-coding sequences.

Five Staphylococcus saprophyticus strains were isolated from the fermented milk product nono in Nigeria and were sequenced using an Illumina MiSeq platform. The genome sizes ranged from 2.53 to 2.60 Mbp, while the GC contents ranged from 32.99 to 33.07 mol%. The genomes possessed 2,505 to 2,687 protein-coding sequences.

Methicillin-Resistant Staphylococci and Macrococci at the Interface of Human and Animal Health

The global impact of methicillin-resistant Staphylococcus aureus (MRSA) clonal lineages on human and animal health continues, even considering the decreasing MRSA rates in some parts of the world [...].