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Background: Methicillin-resistant Staphylococcus aureus (MRSA) can cause serious infections not only in hospitals but also in the community. The present study was aimed to characterize drug resistance and virulence determinants of community-associated (CA) MRSA isolate compared with healthcare-associated (HA) MRSA. Materials and Methods: A total of 44 patients with HA-MRSA and 11 patients with CA-MRSA infection (median age, 72 years) were included. The clinical isolates of MRSA were subjected to molecular analysis of virulence genes and drug susceptibility testing. Results: Panton-Valentine leucocidin (PVL) exotoxin and toxic shock syndrome toxin (TSST) genes were disproportionately distributed between CA- and HA-isolates. PVL genes were more likely to be found among CA-isolates (36.4%) than HA-isolates (18.2). TSST genes were identified in only 2 CA-MRSA isolates tested (18.2%) compared with 9 HA-isolates (20.5%). Exfoliative toxin- b gene was negative in all isolates, however, one HA-isolate was positive for exfoliative toxin-a. mec-A gene was present in all clinical isolates. CA-isolates were more likely to be susceptible to trimethoprim-sulfamethoxazole and vancomycin compared with HA-isolates. Vancomycin-intermediate resistance was found in 2 HA-isolates. All clinical isolates were also resistant to clindamycin. Conclusions: CA- and HA- MRSA isolates are epidemiologically and microbiologically distinct. Thus, the strategies to prevent and treat these infections would be different. Patients with CA- and HA-MRSA infections should be treated effectively and receive follow-up evaluation to ensure the resolution of their infection. Surveillance studies should be conducted to determine the extent of CA- and HA-MRSA dissemination in Iran.

Three hundred and sixty different samples were collected from different sources, including wound, burn, nasal, and oral swabs from several hospitals in Baghdad. A number of 150 (53%) Staphylococcus aureus samples were isolated and identified among a total of 283 samples. Then, the spread of the Toxic Shock Syndrome Toxin-1 gene (tsst-1) was investigated in β-lactamase resistant S. aureus. According to the source of samples, the distribution of S. aureus isolates was found to be significantly higher (p < 0.01) in wound samples as compared to other sources. According to the age, a highly significant distribution (p < 0.01) was recorded in the age group of 15-30 years, whereas gender comparison showed no statistically significant differences. All the isolates were subjected to susceptibility test against eight β-Lactam antibiotics by using the disc diffusion method. The antimicrobial susceptibility test showed that S. aureus had maximum resistance percentage to Carbenicillin (97.3%), while the lowest resistance rate was against Meropenem, with a sensitivity rate of up to 82%. In addition, 144 (96%) out of the 150 S. aureus isolates have multiple drug resistance (MDR). All the isolates were subjected to polymerase chain reaction to amplify tsst-1 toxin gene. A number of 70 isolates (46.7%) were found to be positive for tsst-1 gene. The results showed no significant correlation between tsst-1 gene with the individual antibiotic resistance and the multi-drug resistance patterns of the isolates (p = 0.226).

Methicillin-resistant Staphylococcus aureus (MRSA) is a widespread pathogen that could cause different illnesses in both human and animals. Presence of MRSA in animals raises concerns of their capacity to act as reservoirs, particularly in wild animals. This study aimed to characterize the resistance and virulence patterns of S.&nbsp, aureus strains isolated from bat guano in Algeria. From March to May 2016, 98 bat guano samples from Aokas’s cave (Bejaia, Algeria) were collected. Swabs were taken for microbiological studies. Isolates were identified by Vitek® MS system, and antibiotic susceptibility was determined by disk diffusion method. The clonal origin, virulence and antibiotic resistance profiles of S. aureus isolates were characterized by whole genome sequencing. Eleven S.&nbsp, aureus strains were obtained from the 98 guano samples. Seven isolates were sensitive to all antibiotics tested and four (36.3%) were resistant to penicillin G, cefoxitin and fusidic acid. The four MRSA isolates were assigned to the sequence type ST149 and related to spa type t010. These isolates harbored a SCCmecIV element and the fusidic acid resistance element Q6GD50 (fusC). They carried different virulence genes including several enterotoxins (sea, egc enterotoxin locus, sec, sel), and the toxic shock syndrome toxin (tst). Our results highlight that bat guano may constitute an important reservoir of MRSA strains.

Ο ανθεκτικός στη μεθικιλλίνη Staphylococcus aureus (MRSA) αποτελεί σημαντικό αίτιο ενδονοσοκομειακών λοιμώξεων (HA-MRSA) καθώς επίσης και της κοινότητας (CA-MRSA). Οι σοβαρές λοιμώξεις από MRSA έχουν συσχετιστεί με τον λοιμογόνο παράγοντα Panton-Valentine leukocidin, (PVL). Μέρος αυτής της μελέτης ήταν να διερευνήσει τα πρότυπα ευαισθησίας, την παρουσία γονιδίων τοξινών συμπεριλαμβανομένης και της PVL και την κλωνικότητα μεταξύ MRSA που συλλέχθηκαν από ασθενείς στην Ελλάδα κατά τη διάρκεια μιας περιόδου έξι ετών. Συνολικά, 1678 MRSA συλλέχθηκαν από τον Ιανουάριο του 2007 μέχρι το Δεκέμβριο του 2012 από δύο διαφορετικά νοσοκομεία στη Δυτική Ελλάδα και ταυτοποιήθηκαν με βάση την ανίχνευση των γονιδίων nuc και mecA με PCR. Η αντοχή στα αντιβιοτικά πραγματοποιήθηκε με τη μέθοδο διάχυσης των δίσκων και το E-test. Η παρουσία των γονιδίων που κωδικοποιούν την τοξίνη TSST-1, την PVL και ορισμένα γονίδια των εντεροτοξινών ελέγχθηκε με PCR. Τα γονοτυπικά χαρακτηριστικά των στελεχών αναλύθηκαν με την ταυτοποίηση των τύπων SCCmec και agr. Η κλωνικότητα καθορίστηκε μέσω PFGE και MLST. Η πλειοψηφία των PVL-θετικών MRSA ανήκε στον ST80-IV κλώνο ο οποίος διεσπάρη στην κοινότητα αλλά και τα νοσοκομεία. CA-MRSA απομονώθηκαν κυρίως από SSTIs, ενώ HA-MRSA συνδέθηκαν με χειρουργικές λοιμώξεις και μολύνσεις τραυμάτων. Κατά την περίοδο 2007-2012, ο ST80-IV έχει κυριαρχήσει στην Ελλάδα και έχει περιορίσει με επιτυχία την παρουσία άλλων PVL-θετικών κλώνων. Το δεύτερο μέρος της παρούσας μελέτης επικεντρώνεται στην μελέτη διασποράς των S. aureus και MRSA μεταξύ των ζώων συντροφιάς και του κτηνιατρικού προσωπικού (ΚΠ) στην Βόρεια Ελλάδα. Τα μοριακά χαρακτηριστικά των στελεχών αξιολογήθηκαν, προκειμένου να εκτιμηθεί εάν υφίσταται μετάδοση του S. aureus. Δείγματα (224) που αποίκισαν και μόλυναν 102 ζώα (92 σκυλιά, 10 γάτες) και 18 ΚΠ, συλλέχθηκαν κατά τη διάρκεια του 2012 και του 2013. Η ευαισθησία στα αντιβιοτικά διερευνήθηκε με τη μέθοδο διάχυσης των δίσκων και E-test. Τα mecA, mecC, tst και lukF/lukS-PV γονίδια μελετήθηκαν με PCRs. Οι γονότυποι προσδιορίστηκαν με την ταυτοποίηση των τύπων MLST, SCCmec, agr, spa και PFGE. Το ποσοστό απομόνωσης S. aureus μεταξύ των κατοικίδιων ζώων και του ΚΠ ήταν 36.3% (37/102) και 38.9% (7/18), αντίστοιχα. Τα νεώτερα ζώα συντροφιάς, όσοι ζουν σε αγροτικές περιοχές, νοσούσαν κατά την εισαγωγή ή ήταν ήδη αποικισμένοι με CNS έδειξαν στατιστικά σημαντικά αυξημένο κίνδυνο για προσβολή από S. aureus (p

Staphylococcus aureus is one of the predominant bacteria isolated from skin and soft tissue infections and a common cause of bloodstream infections. The aim of this study was to compare the rate of resistance to various antimicrobial agents and virulence patterns in a total of 200 S. aureus strains isolated from patients with bacteremia and chronic wounds. Disk diffusion assay and in the case of vancomycin and teicoplanin-microdilution assay, were performed to study the antimicrobial susceptibility of the isolates. The prevalence of genes encoding six enterotoxins, two exfoliative toxins, the Panton–Valentine leukocidin and the toxic shock syndrome toxin was determined by PCR. Of the 100 blood strains tested, the highest percentage (85.0%, 31.0%, and 29.0%) were resistant to benzylpenicillin, erythromycin and clindamycin, respectively. Out of the 100 chronic wound strains, the highest percentage (86.0%, 32.0%, 31.0%, 31.0%, 30.0%, and 29.0%) were confirmed as resistant to benzylpenicillin, tobramycin, amikacin, norfloxacin, erythromycin, and clindamycin, respectively. A significantly higher prevalence of resistance to amikacin, gentamicin, and tobramycin was noted in strains obtained from chronic wounds. Moreover, a significant difference in the distribution of sea and sei genes was found. These genes were detected in 6.0%, 46.0% of blood strains and in 19.0%, and 61.0% of wound strains, respectively. Our results suggest that S. aureus strains obtained from chronic wounds seem to be more often resistant to antibiotics and harbor more virulence genes compared to strains isolated from blood.

The aim of the present study was to identify predictors of fatality among patients with S. aureus infections requiring hospitalization. Cases hospitalized with S. aureus infections at the University General Hospital of Patras, Greece, during a 4-year period (2013-2016) were studied. mecA, lukS/lukF-PV (Panton-Valentine leukocidin, PVL), tst (toxic shock syndrome toxin), fnbA (fibronectin-binding protein A), eta, and etb (epidermolytic toxins) genes' carriage was detected by PCR in 149 selected patients. Among 464 patients, 346 were included (118 with missing data). Primary bacteremia predominated (44.2%), followed by lower respiratory tract infections (13.6%), deep seated infections (9.8%), osteoarticular (9.5%), and catheter-related bloodstream infections (6.1%). Methicillin-resistant S. aureus (MRSA) represented 33.8% of infections and were less likely to receive appropriate empiric treatment (79.5% versus 97.4%; P < 0.001). Thirty-day fatality was 14.5%. Multivariate analysis revealed that development of septic shock, Charlson Comorbidity Index, lower respiratory tract infection, bacteremia (primary or secondary), MRSA, and CRP was significantly associated with fatality. Appropriate empiric treatment was a predictor of good prognosis. Thirty-two out of 149 S. aureus (21.5%) carried lukS/lukF-PV genes, whereas, 14 (9.4%), 133 (78.7%), four (2.7%), and one (0.7%) carried tst, fnbA, eta, and etb genes, respectively. No difference was found among toxin genes' presence and mortality. PVL was significantly more frequently found among MRSA as compared to MSSA (45.1% versus 9.2%; P < 0.001). MRSA represented one third of the infections requiring hospitalization and were independently associated with fatality, probably since were more likely to receive inappropriate antibiotic treatment as compared to MSSA.

Intramammary infections are a serious problem in dairy sheep farming, and Staphylococcus epidermidis is one of the main etiological agents of ovine mastitis. In this work, 199 S. epidermidis isolates collected in Sardinia (Italy) from sheep milk samples and used for the preparation of inactivated autogenous vaccines were characterized with phenotypic and genotypic methods. The potential for biofilm production was evaluated phenotypically by assessing colony characteristics on Congo Red Agar (CRA), and genotypically by PCR for i) the icaA/D genes coding the polysaccharide intercellular adhesin (PIA) and ii) for the bhp, aap and embp genes coding biofilm accumulation proteins. Isolates were also investigated by PCR for the presence of autolysins (atlE and aae genes), microbial surface components recognizing adhesive matrix molecules (MSCRAMMs, sdrG and sdrF genes), enterotoxins (sea, seb, sec, sed and see genes), and the toxic shock syndrome toxin (tsst genes). In addition, the staphylococcal accessory gene regulator (agr), the most important locus responsible for the regulation of virulence factors, was characterized for the first time. As a result, only two isolates showed biofilm production on CRA and harbored the icaA/D genes. Four isolates, phenotypically classified as non-biofilm producers, possessed the icaA/D genes (n = 3) or only the icaA gene (n = 1). All isolates harbored the atlE, aae, embp and sdrG genes, but none harbored the genes encoding enterotoxins and tsst. Most isolates belonged to the agr-3se group (56.3%), followed by agr-1se (41.2%) and agr-2se (2.5%). All six isolates that harbored ica genes belonged to agr-1se. In conclusion, this study provides a detailed characterization of the putative virulence genes present in S. epidermidis strains circulating in Sardinian sheep. Because of their role in ovine mastitis pathogenesis, these might represent valuable candidates for vaccine development.

Background Staphylococcus aureus is a common pathogen causing hospital acquired infections (HAIs) in neonates. In this study, the epidemiology of methicillin-resistant S. aureus (MRSA) colonization and infections in a 30-bed, level III university-affiliated neonatal intensive care unit (NICU) located in a children's hospital was retrospectively investigated for the period 2014–2018. Methods Genes encoding Panton-Valentine Leukocidin (lukS/lukF-PV, PVL), toxic shock syndrome toxin (tst), exfoliative toxins (eta, etb), and the resistance genes mecA, mecC and fusB, were defined in 46 representative strains by PCRs. Relatedness of strains was assessed by MLST. Results Of 1538 neonates, 77 (5%) had a positive culture for MRSA (23/77 were NICU-acquired and 54/77 imported cases). Four MRSA bacteremias occurred. Most isolates were multi-resistant. One major clone was identified, ST225, among 40 tested neonatal strains (23/40, 58%). Of these, 14/23 were imported from the same maternity hospital (MH). Another clone, ST217, was predominant (4/6) among health care workers (HCWs), found colonized. Four isolates classified as ST80 were PVL-positive. Additional four strains carried tst (10%), belonging to ST30 and ST225 (two strains each), and two etb. The implicated MH was notified for the problem, decolonization treatment was successfully performed in HCWs and neonates. Strengthening of infection control measures with emphasis on hand hygiene was applied. Conclusions Uncovering reservoirs for on-going MRSA transmission in NICUs has proved challenging. Well known nosocomial MRSA clones are being constantly introduced and transmitted via MHs and HCWs. Effective infection prevention and control requires constant vigilance.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a common causative agent of pneumonia; however, the detailed mechanism underlying severe MRSA pneumonia, including association with oral hygiene or periodontitis, remains poorly characterized. In this study, we examined the pathogenic effect of Prevotella intermedia, a major periodontopathic pathogen, on MRSA pneumonia. Methods: The pathogenic effect of the supernatant of P. intermedia (Pi Sup) was investigated in a murine MRSA pneumonia model, using several clinical strains; whereas the bactericidal activity of polymorphonuclear leukocytes (PMNs) was investigated in vitro. The effect of Pi Sup on messenger RNA (mRNA) expression of the toxin/quorum sensing system (rnaIII) was investigated by quantitative reverse transcription PCR both in vitro and in vivo. Results: Mice infected by hospital-acquired MRSA (HA-MRSA) with Pi Sup exhibited a significantly lower survival rate, higher bacterial loads in the lungs, and higher α-hemolysin (hla) expression in the lungs, than those without Pi Sup. A similar effect of Pi Sup was not observed with MRSA strains producing Panton-Valentine leucocidin (PVL) or toxic shock syndrome toxin (TSST). In vitro, Pi Sup suppressed bactericidal activity of PMNs against the HA-MRSA strain. HA-MRSA was the clinical strain with the highest ability to proliferate in the lungs and was accompanied by time-dependent up-regulation of rnaIII and hla. Conclusions: Our results provide novel evidence that the product of P. intermedia exerts a pathogenic effect on MRSA pneumonia, in particular with a strain exhibiting strong proliferation in the lower airway tract. Moreover, our results indicate that P. intermedia affects MRSA toxin expression via quorum sensing in a strain-dependent fashion, which might be important for understanding the pathogenesis of severe MRSA pneumonia.

In this study one handered and five samples were collected from skin infection in hospital Diwaniyah Dermatology Consultancy in Al-Diwaniyah governorate. from December 2018 to April 2019. All samples were cultured and Identified by using phenotyping tests. The results revealed that 41 isolates were Staph. spp. and 30 Isolates out of them Diagnosed Staphylococcus aureus by using (API staph). Virulence factors were explicated by using polymerase chain reaction (PCR) methicillin-resistant staphylococcus aureus ( MRSA ), were identified by detecting (mecA gene), which revealed that all skin infections were MRSA ( 100 % ). Also, toxic shock syndrome toxin ( TSST ) were identified by using PCR to detect ( tst-1 gene 326 bp.), which revealed that 23 isolate were positive out of 30 isolate ( 76.33 % ).

Methicillin-resistant Staphylococcus aureus (MRSA) strains that carry the tst gene are disseminated worldwide with varying regional incidences and different genetic backgrounds. The data on molecular characteristics of these strains is insufficient in Iran. The present study aimed to assess the characteristics and distribution of spa types of tst-positive MRSA strains. We investigated 89 MRSA isolates carrying the tst gene with spa typing, resistance gene detection and in vitro antimicrobial susceptibility. Of the 89 tested isolates, 61 (68.5%) were confirmed as multidrug resistant (MDR). The isolates were distributed across seven clonal complexes (CCs) including CC22 (42.7%), CC8 (28.1%), CC5 (11.2%), CC59 (5.6%), CC30 (4.5%), CC80 (4.5%) and CC15 (3.4%). spa typing identified 11 distinct types, with t223 (16.9%) and t790 (15.7%) being the most prevalent. All high-level mupirocin-resistant strains belonged to t002 (n = 8) and low-level mupirocin-resistant strains belonged to t790 (n = 6) spa types. Fusidic-acid-resistant isolates belonged to t437 (n = 3). iMLSB phenotype was observed in t005 (6.7%), t002 (5.6%), t790 (3.4%), and t030, t044 and t084 (each 2.2%). It was found that in the tst-carrying MRSA strains, there were genetic diversities with a majority of the t223 spa type. Indeed, there is a necessity for more constructive surveillance/infection control strategies to address the prevalence and prevention of the emerging spa types.

Haemophilus influenzae was the main causative organism for acute epiglottitis in the pre-Haemophilus influenzae type b (Hib) vaccine era. However, with current widespread Hib vaccination, the causative organisms may have changed. Here, we report the case of a healthy infant with acute epiglottitis caused by community-acquired methicillin-resistant Staphylococcus aureus (MRSA). The patient was a healthy 17-day-old male infant without a family history of immunodeficiency syndrome. He had not been started on any vaccines. On the third day of illness, he was diagnosed with acute pharyngitis with exudation on the back of the larynx. Although treatment using cefotaxime was initiated, he showed stridor, difficulty in pronunciation, and cyanosis upon crying on the fourth day. On the fifth day, he was diagnosed with acute epiglottitis by laryngoscopy, which showed a downward spread of the exudation and laryngeal edema. He was intubated and started on artificial respiration. Due to the detection of MRSA from a pharyngeal swab culture, he was treated with vancomycin. His fever disappeared on the first day after admission, and he was extubated on the eighth day after admission. MRSA genome analysis of the patient sample revealed negative Panton-Valentine leukocidin, positive toxic shock syndrome toxin 1, and type IV clone of staphylococcal cassette chromosome mec. This is a first case of acute epiglottitis caused by MRSA with a Panton-Valentine leukocidin-negative and toxic shock syndrome toxin 1-positive staphylococcal cassette chromosome mec type IV clone, which is known as a community-acquired MRSA in Japan. Community-acquired MRSA may be considered a causative organism for acute epiglottitis in the post-Hib vaccine era.

Foods may potentially serve as vehicles for the transmission of antimicrobial-resistant variants of Staphylococcus aureus that are important in a human clinical context. Further, retail food products can be a cause of staphylococcal food poisoning. For these reasons and to account for source attribution and risk assessment, detailed information on the population structure, resistance, and virulence profiles of S. aureus originating from retail food products is necessary. In the current study, whole-genome sequences from 88 S. aureus isolates were subjected to bioinformatics analyses in relation to sequence types, antimicrobial resistance, and virulence profiles. The sequence types (ST) identified belonged to 13 clonal complexes (CC) with CC5 and CC398 being the most common. CC398 was identified as the dominant clone (n = 31). CC5 was identified as of avian origin, with the presence of φAVβ prophage genes (n = 13). In total, 39.8% of the isolates contained multiple resistance genes, and methicillin-resistant Staphylococcus aureus (MRSA) isolates were found in CC8, CC9, and CC398. Genes conferring resistance to the antimicrobial classes of β-lactams, tetracycline, and erythromycin were detected in this study, all of which are commonly used in Danish livestock production. The tst gene encoding the toxic shock syndrome toxin was for the first time identified in ST398 isolates, probably as a result of a single acquisition of a SaPI-like element. The sushi-CC398 isolates carrying the scn gene likely originated from a human reservoir, while the other isolates originated from livestock. Taken together, our results show that both human and animal reservoirs contribute to contamination in food products and that retail foods may serve as a vehicle of S. aureus between livestock and humans. Published version

Antimicrobial resistance of Staphylococcus aureus is a major problem in human and veterinary medicine. The aim of this study was to characterise S. aureus isolates from wild and zoo animals mainly associated with bacterial infections. In total, 23 S. aureus isolates, including nine from wild animals and 14 from zoo animals, were obtained during routine diagnostics. All isolates were subjected to multilocus sequence typing (MLST), spa typing, macrorestriction analysis with subsequent SmaI pulsed-field gelelectrophoresis (PFGE), antimicrobial susceptibility testing and S. aureus-specific DNA-microarray analysis. Resistant isolates were also tested for their respective resistance genes by PCR. Isolates from zoo animals and wildlife showed a high diversity of MLST types, spa types and PFGE patterns. Nineteen different spa types were identified, including three novel types and 16 main macrorestriction patterns. Only few isolates were resistant to members of four classes of antimicrobial agents and harboured the respective resistance genes (β-lactams [blaZ, mecA, mecC], tetracyclines [tet(K), tet(L)] and chloramphenicol [catpC221]) or mutations (fluoroquinolones). The DNA microarray analysis identified one isolate from a zoo animal harbouring the toxic shock syndrome toxin gene tst1. Moreover, several enterotoxin genes were detected in five S. aureus isolates. All isolates were negative for Panton-Valentine leukocidin (PVL) genes, but the animal-associated leukocidin genes lukM/lukF-P83 were found in three isolates from two animals.

The aim of this study was to investigate the toxin gene profile and antimicrobial resistance of Staphylococcus aureus isolates from raw chicken in the People's Republic of China. In total, 289 S. aureus isolates were characterized by antimicrobial susceptibility testing, and genes encoding enterotoxins, exfoliative toxins, Panton-Valentine leukocidin, and toxic shock syndrome toxin were revealed by PCR. Overall, 46.0% of the isolates were positive for one or more toxin genes. A high proportion of toxin genes were pvl (26.6%), followed by sej (12.5%), sea (9.0%), seh (8.3%), seb (6.9%), sec (6.9%), sed (4.8%), sei (3.1%), and see (2.4%). None of the isolates harbored seg, tsst-1, or exfoliative toxin genes. In total, 29 toxin gene profiles were obtained, and pvl (10.7%) was the most frequent genotype, followed by sea (5.9%), seb (4.8%), and sej (4.2%). Furthermore, 99.7% of the strains were resistant to at least one of the tested antimicrobial agents, and 87.2% of them displayed multidrug resistance. Resistance was most frequently observed to trimethoprim-sulfamethoxazole and erythromycin (86.2% for each), followed by tetracycline (69.9%), amoxicillin-clavulanic acid (45.0%), and ampicillin (42.6%). None of the strains were resistant to vancomycin. This study indicates that S. aureus isolates from raw chicken harbored multiple toxin genes and exhibited multiple antimicrobial resistance, which represents a potential health hazard for consumers.