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The aim of this work is to emphasize that particular stains on the third cervical of the buccal and lingual surfaces in mixed dentition, called "black stain." Previous research showed the microbiological etiology of this discoloration by chromogen bacterias. Our study shows bacteria spp involved in stains by means of PCR process and electrophoresis gel on the agarose medium. Sample was formed by 100 subject with black stain and 100 control subjects stain-free.A statistical analysis (SPSS 10.0) using X2 was performed in this study. Porphyromonas gingivalis and Prevotella melaninogenica, were not involved in both in black stain subjects and in the control. On the contrary, Actinomyces could be involved in the pigmentation process.

Antimicrobial resistance (AMR) is a major threat to global health. Understanding the emergence, evolution, and transmission of individual antibiotic resistance genes (ARGs) is essential to develop sustainable strategies combatting this threat. Here, we use metagenomic sequencing to analyse ARGs in 757 sewage samples from 243 cities in 101 countries, collected from 2016 to 2019. We find regional patterns in resistomes, and these differ between subsets corresponding to drug classes and are partly driven by taxonomic variation. The genetic environments of 49 common ARGs are highly diverse, with most common ARGs carried by multiple distinct genomic contexts globally and sometimes on plasmids. Analysis of flanking sequence revealed ARG-specific patterns of dispersal limitation and global transmission. Our data furthermore suggest certain geographies are more prone to transmission events and should receive additional attention.

Seven Klebsiella pneumoniae isolates from dogs and cats in Spain were found to be highly resistant to aminoglycosides, and ArmA methyltransferase was responsible for this phenotype. All isolates were typed by multilocus sequence typing (MLST) as ST11, a human epidemic clone reported worldwide and associated with, among others, OXA-48 and NDM carbapenemases. In the seven strains, armA was borne by an IncR plasmid, pB1025, of 50 kb. The isolates were found to coproduce DHA-1 and SHV-11 ␤-lactamases, as well as the QnrB4 resistance determinant. This first report of the ArmA methyltransferase in pets illustrates their importance as a reservoir for human multidrug-resistant K. pneumoniae.

BackgroundStudies have implicated Staphylococcus aureus as the leading cause of septicemia in the Tamale metropolis of Ghana. The aim of this study was to determine the prevalence and antibiotic susceptibility of S. aureus and Methicillin Resistant S. aureus (MRSA) in the environments of three hospitals in Ghana.MethodsA total of 120 swab samples were taken from door handles, stair railings and other points of contact at Tamale Teaching Hospital, Tamale Central Hospital and Tamale West Hospital. The swab samples were directly plated on Mannitol Salt and Baird Parker agar plates and incubated at 37 °C (± 2) for 18–24 h. An antibiotic susceptibility test was performed using the Clinical Laboratory Standard Institute’s guidelines. Isolates resistant to both cefoxitin and oxacillin were considered to be MRSA.ResultsA total of 47 (39%) positive S. aureus samples were isolated from all three hospitals, of which, eight (17%) were putative MRSA isolates. One MRSA isolate was resistant to all the antibiotics used (cefoxitin, oxacillin, ciprofloxacin, erythromycin, tetracycline, ampicillin, streptomycin and sulfamethoxazole-trimethoprim). Five of the MRSA isolates were multi-drug resistant, whilst the other three were resistant to only two antibiotics. All the multi-drug resistant MRSA isolates were resistant to at least four antibiotics. The percentage of isolates resistant to oxacillin, ampicillin, ciprofloxacin, tetracycline, streptomycin, erythromycin, and sulfamethoxazole/trimethoprim were 17, 13, 9, 28, 89, 13 and 11% respectively.ConclusionThe high multi-drug resistance of MRSA in hospital environments in Ghana reinforces the need for the effective and routine cleaning of door handles in hospitals. Further investigation is required to understand whether S. aureus from door handles could be the possible causes of nosocomial diseases in the hospitals.Electronic supplementary materialThe online version of this article (doi:10.1186/s13756-017-0203-2) contains supplementary material, which is available to authorized users.