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Background Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. Materials and methods We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with community-acquired (CA) and healthcare-associated (HCA) PM. Results One hundred eleven organisms were isolated from 96 (68.6%) patients with PM. Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S. aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). Conclusion Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea.

Subretinal abscesses due to endogenous staphylococcal blood stream infection is a rare occurrence. A young adult male presented with subretinal abscesses, necrotising pneumonia, pleural empyema, skin and soft tissue infection, muscle abscesses and deep vein thrombosis. Aspirate from one of the abscesses and blood culture revealed meticillin-susceptible Staphylococcus aureus. We present here a case of probable Panton–Valentine leucocidin (PVL) syndrome. PVL is a cytotoxin produced by S. aureus. Infection with PVL-positive S. aureus produces a clinical disease that is characterised by necrotising pneumonia and disseminated infection that often carries a high mortality. Our patient showed prompt clinical response to cloxacillin that was given for a total duration of 6 weeks. At the end of 6 weeks vision also recovered. The successful outcome in our patient was likely due to early and appropriate antibiotic therapy.

Despite the widespread use of contact precautions in acute care hospitals, even after decades of experience, the use of contact precautions (CP) remains controversial. This paper aims to review the current controversies related to CP in acute care hospital settings, identify potential areas for future study, and provides updated information where available.

The relative high burden of morbidity and mortality caused by Staphylococcus aureus (SA) in healthcare and community settings is a major concern worldwide. It can cause invasive infections, sepsis and deaths. Despite progress in methicillin-resistant S. aureus (MRSA) prevention in healthcare settings, there is a critical need for assessment of the problem in both healthcare and community settings. This study was conducted for examining the prevalence, risk factors and antimicrobial susceptibility of MRSA in Mansoura University Hospitals (MUHs), Egypt. Samples were collected from patients in MUHs with clinically suspected nosocomial infections. MRSA isolates were identified by the standard bacteriological methods, biochemical reactions and disc diffusion method as recommended by the Clinical & Laboratory Standards Institute (CLSI), then confirmed by MecA gene PCR. A total of 2006 isolates was obtained. SA (32%) was the most frequently isolated pathogen. MRSA (130 isolates) represented 20% of SA and 6.48 % of all isolates. The mecA PCR identified SA as MRSA in 99.2% of cases. MRSA was isolated with another organism (mostly Gram-negative bacilli) from 40.8% of cases while 59.2% of MRSA was isolated alone. The most important reported risk factors for MRSA infections were prolonged hospital stays, recent antibiotic therapy, ICU admission, indwelling devices and presence of surgical sutures. MRSA was resistant to many antibiotics but sensitive to vancomycin in 99.2% of cases. Minimizing exposure to the risk factors with rapid diagnosis of MRSA infections are essential for early initiation of appropriate antibiotic treatment and limitation of the non-optimal use of glycopeptides and deaths.

Background The production and commercialization of tilapia (Oreochromis niloticus) is fundamentally important to the semi-arid region of northeastern Brazil. In this region, one of the main forms of commercialization occurs in street markets (fairs). A high incidence of methicillin-resistant Staphylococcus aureus (MRSA) strains was previously detected in different food-related environments in Brazil. However, limited data is available about the presence of MRSA in street markets commercializing tilapias. In this study, we identified Staphylococcus aureus from tilapia and utensils used in the commercialization of tilapia in the street markets of a semi-arid Brazilian municipality and characterized the virulence potential of the isolates by analyzing their b-lactam resistance, intercellular adhesion and enterotoxin genes. Methods The study used samples from the 5 main markets in the city. Phenotypic tests to determine antimicrobial resistance, exopolysaccharide (EPS) production, the potential for biofilm formation and cell surface hydrophobicity were conducted on S. aureus isolates. The presence of antimicrobial resistance genes (mecA and blaZ), potential biofilm production genes (icaA and icaD) and enterotoxin (se) genes was investigated. Results Coagulase-positive staphylococci (CoPS) were detected in samples from all markets in discordance with the legal limits in force. Twelve isolates were confirmed to be S. aureus. Ten isolates demonstrated multidrug resistance (MDR). All isolates were able to produce EPS and form biofilms. Eight isolates exhibited strong hydrophobicity and six a high potential for biofilm formation. Twelve isolates were positive for mecA, blaZ, icaD and sed. Conclusions Tilapia marketed in unsuitable conditions may be a vehicle for staphylococcal food poisoning and for the dissemination of MRSA to consumers. Additionally, the ability of the isolates to produce biofilms is an alert to the presence and persistence of these virulent microorganisms on utensils used for the commercial distribution of tilapia.

The clinical significance of long-term methicillin-resistant Staphylococcus aureus (MRSA) bacteremia remains unclear. We evaluated the clinical, microbiological characteristics, and clinical outcomes of long-term MRSA bacteremia. A nested case-control study was conducted in a prospective cohort of adult patients with MRSA bacteremia at a tertiary hospital between August 2008 and December 2017. Patients with long-term MRSA bacteremia (≥ 14 days) were compared with control patients, defined as having bacteremia that resolved in less than 3 days. The following variables were documented: heteroresistance phenotype, genotypes, agr dysfunction, and the presence of 41 virulence genes in isolates. Of the total 890 patients studied, 69 patients (7.8%) exhibited long-term MRSA bacteremia and 599 (67.3%) exhibited resolving bacteremia. The most common sources of long-term bacteremia were central venous catheter–related infection (39%) and osteomyelitis (19%). Independent risk factors for long-term MRSA bacteremia included male sex (adjusted odds ratio [aOR] = 2.43), community-acquired bacteremia (aOR = 2.93), the presence of a prosthetic device (aOR = 3.40), and osteomyelitis (aOR = 7.98). Metastatic infections developed more frequently in patients with long-term bacteremia than in those with resolving bacteremia (56.5% vs. 8.0%; P

This study presents molecular characteristics of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) from pigs and swine workers in central Thailand. Sixty-three MRSA isolates were recovered from pigs (n = 60) and humans (n = 3). Two major LA-MRSA lineages, including sequence type (ST) 398 and clonal complex 9 (ST9 and ST4576, a novel single-locus variant of ST9), were identified. ST398 had spa type t034 (n = 55). ST9 and ST4576 had t337 (n = 8) and carried staphylococcal cassette chromosome mec (SCCmec) IX only. MRSA-ST398-t034 contained various SCCmec, including SCCmec V (n = 42), a novel SCCmec composite island (n = 12), and a nontypeable SCCmec (n = 1). All isolates were multidrug resistant and carried common resistance genes found in LA-MRSA. This is the first report of the presence of swine MRSA ST398 and multidrug resistance gene cfr in MRSA ST9 in Thailand. With identical molecular characteristics, pigs could be a source of MRSA ST398 spread to humans. A minor variation of genetic features and resistance gene carriage in both lineages represented a heterogeneous population and evolution of the endemic clones. A monitoring program and farm management, with prudent antimicrobial uses, should be implemented to reduce spreading. Strict hygiene and personal protection are also necessary to prevent transfer of LA-MRSA to humans.

Panton-Valentine leukocidin (PVL)-positive USA300 clone is a highly pathogenic and global epidemic community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone. Athletes are particularly vulnerable to CA-MRSA infection because of the frequency of skin trauma, close-contact situations, and sharing of equipment that is customary in the athletic setting. We experienced a case of Japanese collegiate football player with septic pulmonary emboli secondary to infectious iliofemoral deep venous thrombosis caused by the USA300 clone. Here, we screened the nasal carriage of USA300 clone colonization among asymptomatic teammate of the patient to elucidate the infection route. Among 69 nasal samples, CA-MRSA strains were found in 5.8% (four samples). Molecular epidemiological analyses showed that three of the CA-MRSA strains were USA300 clone. Furthermore, pulsed-field gel electrophoresis revealed that all nasal USA300 clones showed 100% identity with the USA300 clone isolated from their teammate with critical infection. Our findings indicate that nasal colonization of the PVL-positive CA-MRSA, especially USA300 clone, pose a threat among contact sport athletes in Japan likewise other countries. An immediate infection control strategy for contact sport athletes is necessary to prevent outbreaks of PVL-positive CA-MRSA infections.

Methicillin Resistant Staphylococcus aureus (MRSA) is type of Staphylococcus aureus resistant to beta-lactam antibiotics, such as meticillin, penicillin, amphycillin, and amoxycillin. The percentage of MRSA occurrence in Indonesia is quite high namely 23.5%. MRSA detection can be done using culture method and Polymerase Chain Reaction (PCR). This research aims to find out the comparison of speed and sensitivity between the culture method and Polymerase Chain Reaction (PCR) in detecting Methicillin Resistant Staphylococcus aureus towards the patients of RSUD Dr. Moewardi Surakarta. This research used experimental analytic research design along with comparative research design. This experiment observed 3 samples of bacterial isolates Staphylococcus aureus MRSA suspect patients of RSUD Dr. Moewardi Surakarta. The detection of MRSA was conducted using disk diffusion test of penicillin, amphycillin, amoxycillin and vancomisin as well as using Polymerase Chain Reaction (PCR). The results of the research indicate that Polymerase Chain Reaction (PCR) method was faster and more sensitive to detect Methicillin Resistant Staphylococcus aureus on the patients of RSUD Dr. Moewardi Surakarta.

Staphylococcus aureus (S. aureus) is one of the most concerning foodborne pathogens due to its ability to produce wide varieties of heat-stable enterotoxins. Hence, this study was designed to investigate the prevalence of the enterotoxigenic S. aureus strains and their enterotoxins in milk and in some representative artisanal Egyptian dairy products. Additionally, the prevalence of Methicillin-Resistant S. aureus (MRSA; antibiotic resistant strain) was considered throughout the study. Three-hundred and fifty samples (n = 350) were randomly collected from Assuit city in upper Egypt, including market cow's milk, yoghurt, Domiati cheese, Kareish cheese, Ras cheese, cooking butter and small-scale ice cream. The identification of the S. aureus strains was done using conventional biochemical method (catalase test, egg yolk reaction test, anaerobic utilization of mannitol and coagulase test) and PCR. Furthermore, Staphylococcal enterotoxins genes (SEA and SED) were detected by PCR while the classical enterotoxins were examined in 30 samples of Ras cheese and small-scale ice cream using ELISA technique. S. aureus was isolated from 142 out of 350 (41%) [95% CI: 35.4–45.7%] examined samples at levels of up to 5.79 log10 cfu/ml or g. The prevalence of S. aureus was significantly (P

Background & Objective: Diabetic foot ulcer (DFU), is one of the most frequent causes for hospitalizations in patients with diabetes. A major problem in the treatment of DFU is the increased-incidence of methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to determine the SCCmec types of MRSA isolates and their epidemiology among patients with diabetes. Methods: This study was carried out on 145 diabetic patients with DFUs. The antibiotic susceptibility tests (ASTs) were performed using the disk diffusion method and E-test technique. SCCmec typing was done by multiplex PCR. Moreover, the presence of virulence toxin genes, including pvl and lukED was detected by PCR assay. Results: In 145 samples from which S. aureus was predominantly isolated, 19.48% were MRSA. Analysis of MRSA isolates revealed that the most prevalent SCCmec type was type IV (46.7%) followed by type III (30.0%) and type V (20.0%). One strain (3.3%) was untypeable. The prevalence of pvl and lukED was 56.7% and 100%, respectively. Conclusion: The high prevalence of MRSA in DFUs represents the high levels of antibiotic usage among patients with diabetes. In this study, resistance to other important clinical antibiotics was detected among MRSA isolates. The high proportion of SCCmec type IV and V strains, even in former hospitalized patients, indicates the entrance of these clones to the clinical setting.

Background Several reports designate the recent increase in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) nasal carriage. Because of the scanty information regarding the nasal carriage sate of MRSA in the west of Iran, the purpose of the present study was to determine the frequency of CA-MRSA in Sanandaj city. Methods Swabs collected from anterior nares of 600 volunteers were analyzed for the presence of S. aureus. The isolates were further investigated for methicillin resistance by using the cefoxitin disk diffusion test, followed by PCR-amplification of the mecA gene. SCCmec types and the presence of the Panton-Valentine Leukocidin (pvl) encoding genes were determined through PCR. Finally, the antimicrobial susceptibility of the isolates was determined by the agar diffusion method. Results Nasal screening identified 181 S. aureus, of which 55 isolates were MRSA. SCCmec types IV and V were detected in MRSA at frequencies of 80 and 20%, respectively. The overall frequency of pvl genes among the MRSA isolates was 14.54%. MRSA isolates were highly susceptible (98.18%) to mupirocin, gentamicin, and fusidic acid. Conclusions The high prevalence of CA-MRSA carriage in the population could pose a serious public health concern for the region. Additionally, advent of drug-resistant pvl-positive strains demands continuous surveillance on the colonization state of CA-MRSA in order to prevent dissemination of the bacterium in the community.

Introduction: Staphylococcal colonization is a risk factor for healthcare-associated infections, which are frequent in Neonatal Intensive Care Units (NICU). This study analyzed microbiology, epidemiology and clinical aspects of Staphylococcus spp. colonizing neonates. Methodology: Nasal or periumbilical swabs were evaluated from 175 newborns admitted to a NICU of a Rio de Janeiro hospital from March to September 2009. Clinical data were obtained from the medical records. SCCmec typing and the mecA and Panton-Valentine Leukocidin (PVL) genes were detected by PCR. Clonal diversity was evaluated by pulsed-field gel electrophoresis. Results: Staphylococcus spp. isolates were detected in 98 (56%) neonates, 66.3% of them had birth weight ≤ 2500 g, 62.2% were preterm (˂ 37 weeks) and the mean length of hospitalization was 14.9 days. Among the 133 isolates identified, 48.1% were S. epidermidis, 23.3% S. haemolyticus and 13.5% S. aureus. Methicillin-resistant Staphylococcus isolate was detected in 77.6% of neonates. The methicillin-resistant S. aureus isolates carried the SCCmec type IV, while 94.6% of S. epidermidis and 85.7% of S. haemolyticus presented non-typeable cassettes. Among the S. aureus, 55.6% had PVL genes and the USA800 genotype was prevalent. Two genotypes of S. epidermidis and one of S. haemolyticus clustered 42.2% and 25.8% of the isolates, respectively. S haemolyticus colonization was associated with the use of parenteral nutrition and mechanical ventilation. Conclusion: High rate of neonates colonized by methicillin-resistant Staphylococcus species and the permanence of clones circulating in the NICU highlight the importance for continuous and preventive surveillance in this high-risk population.

Staphylococcus aureus (S.aureus) and coagulase negative Staphylococci (CONS) are the commonest pathogens that lead to severe bacterial infections. It is a bacterium with consistent resistance development against commonly used antibiotics, with emergence of Methicillin resistant staphylococcus aureus (MRSA) causing several infections in patients following hospitalization. Glycopeptides like vancomycin is used as primary drug for treating infectious diseases caused by MRSA. Due to indiscriminate use of vancomycin to treat MRSA, several strains with variable susceptibility to the same have emerged. Evaluation of Vancomycin Minimum Inhibitory Concentration (MIC) in the MRSA isolates obtained from clinical samples received in the diagnostic microbiology laboratory. About 120 Staphylococci obtained from different clinical samples in the diagnostic Microbiology laboratory, at tertiary health care center, South India, were included in the study. The isolates were identified and susceptibility to the relevant antibiotics was done by Vitek 2 an automated system. Vancomycin MIC was detected by Vitek 2 and E-test strip technique. Out of 120 Staphylococcal strains, 79(65.8%) S. aureus and 41(34.1%) CONS were isolated. Methicillin resistance was observed in 38 (48.1%) strains of S. aureus. Almost all 38 MRSA isolates were vancomycin sensitive with MIC range of 0.5 - 2µg/ml. Maximum isolates had MIC of 1 µg/ml i.e. 65.78% and 71% by E-Test and Vitek 2 respectively. The reported increased MIC of Vancomycin, though within the susceptible range, might experience poor clinical outcomes. Emergence and spread of resistance to glycopeptides like vancomycin needs to be kept in check by rapidly detecting the strains for resistance and strictly obeying the infection control practices.

Background Surgical site infection is a major postoperative complication after surgical procedures. The effectiveness of postoperative antimicrobial dressings in reducing surgical site infections is unclear and limited information is available on the efficacy of chlorhexidine gluconate (CHG)-impregnated postoperative dressings. Methods A pilot study was conducted to examine the efficacy of an innovative CHG-impregnated postoperative dressing in reducing the burden of methicillin-resistant Staphylococcus aureus (MRSA) in an in vivo porcine, incisional-wound model. Sutured incisional wounds were contaminated with MRSA and then covered with a CHG wound dressing, a placebo control, or a nonantimicrobial gauze. The surviving MRSA population was quantitatively cultured 3 days postprocedure. Results MRSA was not recovered from any of the 8 wounds that were treated with the CHG dressing (limit of detection, approximately 1.7 log10 colony-forming units [cfu]/g tissue). In contrast, the average microbial recovery from wounds treated with the placebo dressing was 4.2 log10 cfu/g and the average microbial recovery from wounds treated with the gauze dressing was 3.2 log10 cfu/g. Conclusions An innovative CHG dressing provided significant antimicrobial activity against MRSA contaminating a surgical wound in a porcine, incisional-wound model. Future clinical studies are needed to assess the efficacy of the CHG dressing to reduce the bacterial burden in postoperative wounds of surgical patients.

Objectives Most vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) are derived from hospital-associated MRSA due to treatment failure; however, the prevalence of hVISA/VISA in community settings remains unclear. Methods Four hundred and seventy-six community-associated isolates were collected between 2010 and 2011 during national surveillance for antimicrobial resistance in 31 county hospitals across China. Drug susceptibility evaluation and mecA detection were performed by using broth microdilution and PCR analysis, respectively. hVISA/VISA were identified by using macro-Etest and a modified population analysis profile (PAP)-AUC method. The genetic features of all hVISA/VISA isolates were genotyped. Results Among 476 isolates, MRSA and MSSA accounted for 19.7% (n = 94) and 80.3% (n = 382), respectively. Two VISA and 36 hVISA isolates were identified by PAP-AUC testing. The VISA isolates and 29 of the hVISA isolates were MRSA. The proportion of hVISA/VISA was significantly higher in MRSA (30.9%) than in MSSA (1.8%). The hVISA/VISA isolates were assigned to 18 STs classified into seven clonal complexes (CCs). CC121 (n = 12) followed by ST239 (n = 11) was the most prevalent hVISA/VISA clone. All ST239-hVISA/VISA were MRSA, while 12 CC121-hVISA isolates included 6 MSSA and 6 MRSA isolates. SCCmec III was predominant among MRSA-hVISA/VISA isolates. agr I and agr IV were detected in ST239 and CC121, respectively. All except two strains were positive for Panton–Valentine leucocidin genes. Conclusions To the best of our knowledge, this is the first report of CC121 as a prevalent hVISA clone in community settings, highlighting the necessity of surveillance and stricter infection control measures for this globally disseminated lineage.

The present study was conducted on 250 diseased Nile tilapia (Oreochromis niloticus) fish of various sizes were collected from different fish markets at Kaliobia Governorate, Egypt, during the period from May (2017) to January (2019) for inspection of Aeromonas and Pseudomonas strains. Samples were collected from apparently pathognomic lesions in muscle, liver, kidney, intestine and spleen for bacteriological examination. The results revealed that, 161 Aeromonas and Pseudomonas species; 118 Aeromonas (73.3%) and 43 Pseudomonas species (26.7%) were isolated mostly from 50 muscle lesion samples followed by 41 liver samples then 35 kidney samples ; 32 intestine samples and 3 spleen lesion samples . Aeromonas strains were highly sensitive to meropenem followed by ciprofloxacin; norfloxacin; gentamycin and florphenicol. Meanwhile, they were highly resistant for ampicillin and methicillin followed by oxacillin; penicillin-G; amoxicillin; cefotaxime; oxytetracycline and streptomycin. In addition, Pseudomonas strains were highly sensitive to meropenem followed by gentamycin; norfloxacin; ciprofloxacin and florphenicol. In contrast, they were highly resistant for ampicillin; methicillin and penicillin-G followed by amoxicillin; oxacillin and cefotaxime.

Introduction: Patients with hematological malignancies, who are in the high risk group for infectious complications and bacterial bloodstream infections. The aim of the study evaluated epidemiology and mortality in bacterial bloodstream infections in patients with hematologic malignancies. In addition to determine the risk factors, changes in the distribution and frequency of isolated bacterias. Methodology: In this retrospective study. There were investigated data from 266 patients with hematological malignancies and bacterial bloodstream infections who were hospitalized between the dates 01/01/2012 and 12/31/2017. Results: There were 305 blood and catheter cultures in febrile neutropenia attacks in total. In these total attacks, primary bloodstream infections were 166 and catheter-related bloodstream infections were 139. In blood cultures; Escherichia coli and Klebsiella pneumoniae bacteria were detected in 58,0% and 22,9% of the samples, respectively. 52,4% of the cultured Gram-negative bacterias were extended spectrum beta-lactamase (ESBL). Carbapenemase positive culture rate was 17,2% in Gram-negative bacteria cultures. Staphylococcus epidermidis was found in 38,4% of the Gram-positive bacteria cultures. In Gram-positive bacteria; methicillin resistance were detected in 82,2% of the samples. There was a statistically significant relationship between bloodstream infection and disease status. 60 patients with primary bloodstream infections were newly diagnosed. Conclusions: In patients with hematological malignancies, certain factors in the bloodstream infections increase the mortality rate. With the correction of these factors, the mortality rate in these patients can be reduced. The classification of such risk factors may be an important strategy to improve clinical decision making in high-risk patients, such as patients with hematological malignancies.

Methicillin-resistant Staphylococcus aureus (MRSA) nasal carriage is a major risk factor for infection, namely among populations in the community with inherent prompting factors, such as the homeless. In Portugal, there are no data on S. aureus/MRSA nasal carriage among the homeless community. A total of 84 homeless individuals living in Lisbon (34 with no permanent address and 50 living in shelter) were nasally screened for S. aureus/ MRSA. All isolates were characterized to determine antimicrobial susceptibility and clonal type. A total of 43 (51.2%) S. aureus carriers were identified, including a single individual colonized with MRSA (1.2%). S. aureus carriage rate was higher among individuals with no permanent address (58.8% versus 46%), younger (45.7 ± 12.7 versus 52.5 ± 10.8 years), and with diagnosis of asthma (9% versus 0%). The single MRSA belonged to the EMRSA-15 clone (PFGE D, ST15-SCCmec IVh, and spa type t790). Almost half of the methicillin-susceptible S. aureus (MSSA) isolates (41.9%, n = 18) belonged to two major clones, ST398-t1451 (n = 13) and ST30-t399/t11980/t12808 associated with PFGE I (n = 5). A high proportion of isolates showed non-susceptibility to mupirocin (64%), erythromycin (45%), and fusidic acid (20%) and induced resistance to clindamycin (39%). None of the isolates harboured PVL. Our results suggest that the homeless population of Lisbon does not constitute a reservoir of MRSA in the community, but harbour the highly transmissible ST398-t1451 MSSA lineage.

In this study, we investigated the clonality, antibiotic susceptibility and presence of different enterotoxin genes among 49 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from 131 fresh raw meat samples in Tehran, Iran during 2016. 47% of beef, 30% of chicken and 27% of turkey samples were MRSA positive. PhenePlate (PhP typing) revealed the presence of 12 PhP types consisting of five common types and seven single types, and 86% of the strains harbored staphylococcal cassette chromosome mec (SCCmec) type III and type 3 cassette chromosome recombinases (ccr). Moreover, SCCmec type IVa was positive in all isolates with SGA prophage types. High level resistance to ciprofloxacin, erythromycin, tobramycin and kanamycin was also observed. The rate of resistance to most of the antibiotics tested was higher in chicken samples compared to other meat samples. Out of eleven different enterotoxin genes found, sea, sek and seq were the dominant genes in all strains. Our results illustrate the presence and persistence of highly resistant clonal groups of enterotoxin-producing MRSA in meat samples. These isolates had PhP and SCCmec types and prophage patterns which were similar to the clinical isolates previously reported in Iran, supporting the notion of dissemination of the MRSA in the hospital, community, as well food products in Iran.

Summary Background Preterm infants and critically ill neonates are predisposed to nosocomial infections as sepsis. Moreover, these infants acquire commensal bacteria, which might become potentially harmful. On-ward transmission of these bacteria can cause outbreaks. Aim To report the findings of a prospective surveillance of bacterial colonization and primary sepsis in preterm infants and neonates. Methods The results of the surveillance of bacterial colonization of the gut and the respiratory tract, targeting meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and Gram-negative bacteria from November 2016 to March 2018 were analysed. Bacterial colonization was compared to surveillance of sepsis. Findings Six-hundred and seventy-one patients were admitted and 87.0 % (N=584) of the patients were screened; 48.3% (N=282) of the patients screened were colonized with at least one of the bacteria included in the screening; 26.2% of them (N=74) had multi-drug-resistant strains. A total of 534 bacterial isolates were found. The most frequently found species were Escherichia coli, Enterobacter cloacae, Klebsiella oxytoca and Klebsiella pneumoniae. Three MRSA but no VRE were detected. The surveillance detected a K. pneumoniae cluster involving nine patients. There were 23 blood-culture-confirmed sepsis episodes; 60.9% (N=14) were caused by staphylococci. Gram-negative bacteria (one Klebsiella aerogenes and two E. cloacae) caused three sepsis episodes which were preceded by colonization with the respective isolates. Conclusions Surveillance of colonization provided a comprehensive overview of species and antibiotic resistance patterns. It allowed early detection of a colonization cluster. Knowledge of colonization and surveillance of sepsis is useful for guiding infection control measures and antibiotic treatment.

Background/purpose: Methicillin-resistant Staphylococcus aureus (MRSA) can encode proteins which directly bind bacteria to many tissues and medical devices or catheters to trigger pathogenesis. However, the relationship between genetic backgrounds and virulent factors in MRSA isolates remained incompletely understood yet. Methods: MRSA isolates were collected from blood cultures of patients with infective endocarditis, bone/joint infection, skin/soft tissue infection, or catheter-related bacteremia in hemodialysis at a tertiary medical center between 2005 and 2011. MRSA isolates were characterized by the methods of spa, multilocus sequence, and staphylococcal cassette chromosome mec (SCCmec) typing. Identification of virulence gene expression was measured by Power SYBR Green PCR Master Mix. Results: Overall collected were 136 MRSA bacteremic isolates, including those from the cases of infective endocarditis (n = 23), bone/joint infection (n = 49), skin/soft tissue infection (n = 20), or catheter-related bacteremia in patients with acute kidney injury or end-stage renal stage receiving hemodialysis (n = 54). CC8-ST239-MRSA-SCCmec type III-spa type t037 was the most prevalent type observed in all of 136 MRSA bacteremic isolates. The prevalent genes in the group of infective endocarditis were clfA, clfB, fnbA, ebpS, eap, emp, sae, and eno; bone/joint infections clfA, emp, sae, and eno; skin/soft tissue infection eno; hemodialysis catheter-related bacteremia clfA and sae. The distribution of each gene was not statically different among four groups. Conclusions: A major MRSA lineage, CC8-ST239-MRSA-SCCmec type III-spa type t037, is noted among bacteremic MRSA isolates. No disease-specific virulent genes can be identified. Keywords: Bacteremia, Staphylococcus aureus, Virulence factors

Introduction: Methicillin resistant Staphylococcus aureus (MRSA), a major cause of zoonotic infections, has emerged globally in livestock, particularly pigs. People with occupational contact with food producing animals are at high risk of colonization. The aim of this study was to determine the prevalence of MRSA in pigs and abattoir workers throughout Trinidad and Tobago as well as their resistance to other antimicrobial agents. Methodology: Nasal and skin behind the ear swabs from pigs and nasal swabs from humans were enriched in Mueller Hinton broth with 6.5% sodium chloride, followed by phenol red mannitol broth with 75 mg/L aztreonam and 5 mg/L ceftizoxime. The enriched sample was then plated on both CHROMagar MRSA and Brilliance MRSA. All incubation was at 37ºC for approximately 24 h. Suspect MRSA isolates were confirmed as MRSA using the Penicillin-Binding Protein (PBP2a) test kit and polymerase chain reaction (PCR) to detect the mecA gene. Resistance of the S. aureus and MRSA isolates to 16 antimicrobial agents was determined using the disc diffusion method. Results: Of the 929 pigs and 44 humans sampled, MRSA strains were isolated at a frequency of 0.9% (8/929) and 2.3% (1/44) respectively. All isolates exhibited resistance to one or more of the 16 antimicrobial agents. Conclusions: The study demonstrated that pigs and workers at slaughter houses in Trinidad and Tobago harbour multidrug resistance S. aureus and MRSA. This is of public health significance as occupational exposure of humans can lead to an increased risk of infection and therapeutic failure.

Staphylococcus lugdunensis is a coagulase-negative staphylococcus (CoNS) with unusual pathogenicity resembling that of S. aureus. Unlike other CoNS, S. lugdunensis remains susceptible to most antibiotics. The resistance to penicillin varies widely (range, 15–87% worldwide), whereas methicillin resistance is still rare. We aimed to evaluate treatment options for infections caused by S. lugdunensis and more specifically to investigate whether penicillin G could be a better treatment choice than oxacillin. Susceptibility testing was performed using the disc diffusion method for penicillin G, cefoxitin, trimethoprim/sulfamethoxazole, erythromycin, clindamycin, gentamicin, norfloxacin, fusidic acid, rifampicin, and fosfomycin. Isolates susceptible to penicillin G were further tested with a gradient test for penicillin G and oxacillin. Of the 540 clinical isolates tested, 74.6% were susceptible to penicillin G. Among these penicillin-susceptible isolates, the MIC50 and MIC90 values for penicillin G were threefold lower than that for oxacillin. A majority of the isolates were susceptible to all other antibiotics tested. Breakpoints for fosfomycin have not yet been defined, and so no conclusions could be drawn. Two isolates were resistant to cefoxitin and carried the mecA gene; whole-genome sequencing revealed that both harbored the SCCmec element type IVa(2B). S. lugdunensis isolated in Sweden were susceptible to most tested antibiotics. Penicillin G may be a more optimal treatment choice than oxacillin. Although carriage of the mecA gene is rare among S. lugdunensis, it does occur. Electronic supplementary material The online version of this article (10.1007/s10096-019-03571-6) contains supplementary material, which is available to authorized users.

Background Staphylococcus lugdunensis is a significant pathogen that causes community-acquired and nosocomial infections. The high prevalence of oxacillin-resistant S. lugdunensis (ORSL) is of major concern. Resistance to β-lactams is caused by acquisition of the staphylococcal cassette chromosome mec (SCCmec) element. The cassette is highly diverse, both structurally and genetically, among CoNS. Isolates carrying SCCmec II-ST6 are the major persistent clones in hospitals. Objectives To investigate the structure and evolutionary origin of a novel type II SCCmec element in an endemic ST6 S. lugdunensis clone. Methods The structure of the SCCmec II element carried by ST6 strain CGMH-SL118 was determined by WGS and compared with those reported previously. Results A novel 39 kb SCCmec element, SCCmecCGMH-SL118, with a unique mosaic structure comprising 41 ORFs integrated into the 3′ end of the rlmH gene, was observed. Some regions of SCCmecCGMH-SL118 were homologous to SCCmec IIa of the prototype MRSA strain N315. The structure of SCCmecCGMH-SL118 was similar to that of SCCmec IIb of the MRSA strain, JCSC3063, mainly lacking the aminoglycoside resistance determinant pUB110 in the J3 region but containing the insertion sequence IS256 in the J2 region. Notably, SCCmecCGMH-SL118 deletions in the J1 region compared with SCCmec types IIa and IIb, and a high homology to SCCmec elements of Staphylococcus aureus JCSC4610 and Staphylococcus haemolyticus strain 621 were found. Conclusions The genetic diversity of the type II SCCmec element in ORSL suggests that CoNS is a potential reservoir for interspecies transfer of SCCmec to S. aureus in hospitals.

PurposeThis paper aims to evaluate the microbial quality of some traditional cheese samples (sheep, cow and koopeh cheeses) consumed in northwest of Iran, and to detect Shiga-like-toxin-producingEscherichia coli(STEC) and methicillin-resistantStaphylococcus aureus(MRSA) in cheese samples by polymerase chain reaction (PCR) method.Design/methodology/approachAlmost half of the project was based on counting the population of Staphylococcus aureus, total coliforms, Escherichia coli, and total aerobic mesophilic bacteria, also the other section was related to the isolation and the detection of the STEC and MRSA in cheese samples. The findings were compared with standard maximum and threshold values.FindingsThe results revealed that 36.99, 30.14 and 100% of cheeses exceeded the standard threshold value ofE. coli(102), total coliforms (104) andS. aureus(102). However, total coliforms, in any of the cheese samples examined, did not reach the maximum value and only 24.66% of samples exceeded the maximum value ofE. coli. Also, no significant difference (p> 0.05) in counts of each bacterial group examined in sheep, cow and koopeh cheeses was observed. The colony PCR method demonstrated the existence of 19 MRSA and 2 STEC isolates.Originality/valueThis research showed a general overview of the bacterial quality of cheeses in northwest of Iran.

Introduction Dalbavancin is approved for acute bacterial skin and skin structure infections (ABSSSIs) but offers a potential treatment option for complicated invasive gram-positive infections. Importantly, dalbavancin’s real benefits may be in treating complicated infections in vulnerable patient populations, such as persons who inject drugs (PWID). Methods A multicenter retrospective analysis was performed from March 2014 to April 2017 to assess 30- and 90-day clinical cure and adverse drug events (ADEs) in adult patients who received ≥ 1 dose of dalbavancin for a non-ABSSSI indication. Results During the study period, 45 patients received dalbavancin, 28 for a non-ABSSSI indication. The predominant infections treated included osteomyelitis (46%), endovascular infection (25%) and uncomplicated bacteremia (14%). Half of the patients had positive Staphylococcus aureus in cultures, 29% methicillin resistant and 21% methicillin susceptible. Most patients were prescribed dalbavancin as sequential treatment with a median of 13.5 days of prior antibiotic therapy. The most common reason for choosing dalbavancin over standard therapy use was PWID (54%). Seven patients were lost to follow-up at day 30. Of the remaining evaluable patients, 30-day clinical cure was achieved in 15/21 (71%) patients. The most common reason for failure was lack of source control (4/6, 67%). At day 90, relapse occurred in two patients. Three patients had a potential dalbavancin-associated ADE: two patients with renal dysfunction and one patient with pruritus. Conclusions This study demonstrates a possible role for dalbavancin in the treatment of non-ABSSSI invasive gram-positive infections in select vulnerable OPAT patients.

We consider a deterministic model of Methicillin-resistant Staphylococcus aureus infections in hospitals with seasonal oscillations of the antibiotic prescription rate. The model compartments consist of uncolonized patients with or without antibiotic exposure, colonized patients with or without antibiotic exposure, uncontaminated or contaminated healthcare workers, and free-living bacteria in the environment. We apply optimal control theory to this seven-compartment periodic system of ordinary differential equations to reduce the number of colonized patients and density of bacteria in the environment while minimizing the cost associated with environmental cleaning and antibiotic use in a particular time period. Characterizations of optimal control strategies are formulated and the ways hospitals should adjust these strategies for different scenarios are discussed. Numerical simulations strongly suggest that environmental cleaning is essential in the control of MRSA infections and antibiotic usage is suggested to be maintained at the least possible level. Screening, isolating, and shortening the extremely lengthened stays of colonized patients with antibiotic use history are all effective intervention strategies.

Staphylococcus aureus (SA) is a major cause of bacteremia in children. Methicillin-resistant SA (MRSA) is considered a public health threat; however, the differences in the prognosis of children with methicillin-susceptible SA (MSSA) versus MRSA bacteremia are not well defined.Data from all SA bacteremia events in children (0-16 years) from 2002 to 2016 in a single Israeli tertiary center were collected. Positive cultures within 48 hours of hospitalization were considered community associated (CA). Those obtained afterward or from children hospitalized within the previous year were considered health-care associated (HA).We recorded 427 events, 284 (66%) were HA, 64 (15%) were MRSA and 9 (2%) were CA-MRSA. There was no increase in MRSA during the study period. In-hospital, 30-day and 1-year mortality were 3% (12 cases), 3.5% (16 cases), and 12% (50 cases), respectively. A multivariable analysis controlling for demographics, admitting department and prior morbidity showed an increased 1-year mortality in children with HA bacteremia (hazard ratio [HR] 4.1; 95% confidence interval [CI]: 1.3-12) and prior chronic disease (HR 3.4; 95% CI 1.2 to 9.0). MRSA was not independently associated with increased one-year mortality compared with MSSA: HR (95% CI: 1.4 [0.6-3.1]).Short-term pediatric mortality after SA bacteremia is low. HA-SA bacteremia has an increased long-term risk for mortality, particularly in children with chronic diseases. Our data suggest mortality was not increased for MRSA compared with MSSA bacteremia. The very low rate of CA-MRSA bacteremia justifies the current practice not to include glycopeptides in the empiric treatment of CA bacteremia in Israel.

Healthcare-associated infections (HAIs) not only bring additional medical cost to the patients but also prolong the length of stay (LOS). 2119 HAI case-patients and 2119 matched control-patients were identified in 68 hospitals in 14 primary sampling provinces of 7 major regions of China. The HAI caused an increase in stay of 10.4 days. The LOS due to HAI increased from 9.7 to 10.9 days in different levels of hospitals. There was no statistically significant difference in the increased LOS between different hospital levels. The increased LOS due to HAI in different regions was 8.2 to 12.6 days. Comparing between regions, we found that the increased LOS due to HAI in South China is longer than other regions except the Northeast. The gastrointestinal infection (GI) caused the shortest extra LOS of 6.7 days while the BSI caused the longest extra LOS of 12.8 days. The increased LOS for GI was significantly shorter than that of other sites. Among 2119 case-patients, the non-multidrug-resistant pathogens were detected in 365 cases. The average increased LOS due to these bacterial infections was 12.2 days. E. coli infection caused significantly shorter LOS. The studied MDROs, namely, MRSA, VRE, ESBLs-E. coli, ESBLs-KP, CR-E. coli, CR-KP, CR-AB, and CR-PA were detected in 381 cases (18.0%). The average increased LOS due to these MDRO infections was 14 days. Comparing between different MDRO infections, we found that the increased LOS due to HAI caused by CR-PA (26.5 days) is longer than other MDRO infections (shorter than 19.8 days).

Staphylococcus aureus is an opportunistic pathogen causing dental infection and systemic infections in human body. This organism decreases susceptibility to several types of antibiotics every day and becomes more resistant which is a growing sense of concern in this era. Considering this fact, the study was attempted to characterize the S. aureus from human dental infection and to determine the antibiogram profile of isolates. Sixty four (64) samples were collected from the patients with dental infection who visited different dental clinics and hospitals in Mymensingh, Bangladesh for treatment. Isolation and identification of S. aureus were conducted by using cultural, morphological, and biochemical characteristics. Polymerase chain reaction was performed for final confirmation of S. aureus followed by detection of methicillin resistant S. aureus (MRSA) targeting mecA and mecC genes. Antibiotic susceptibility test of isolated bacteria was tested against seven antibiotics by disk diffusion methods. Forty isolates among 64 samples were found positive for S. aureus based on cultural characteristics. Among them 30 isolates were found positive in coagulase test. Depending on the result of coagulase test, all the 30 isolates were subjected to antibiotic sensitivity test and among them 25 were 100% resistant to penicillin, ampicillin and amoxicillin. All the 25 isolates were subjected to polymerase chain reaction (PCR) to identify methicillin resistant gene mecA and mecC. Eight isolates were positive for mecA gene while no isolates were positive for mecC. The present findings conclude that S. aureus is prevalent in dental infections and contain methicillin resistant genes. Key words: Dental infection, Staphylococcus aureus, antibiotic resistance, methicillin resistant S. aureus (MRSA).

The objective of this study was to determine methicillin and vancomycin resistance phenotypically by agar disc diffusion method (ADDM) and minimal inhibitory concentration (MIC) test and genotypically by polymerase chain reaction (PCR) in Staphylococcus aureus strains isolated from goat milk. A total of 466 milk samples were collected from 233 goats in herds with mastitis problems in Burdur province of Turkey. The microorganisms were isolated from 122 (26.18%) of goat milk samples and among these microorganisms 53 (42.06%) were coagulase negative staphylococci (CNS), 43 (34.23%) were Staphylococcus aureus, 16 (12.08%) were Escherichia coli, 10 (7.94%) were Candida spp. and 4 (3.17%) were Brucella melitensis. Seven of S. aureus isolates were determined resistant to methicillin by ADDM and five of these isolates were found resistant to methicillin by MIC. mecA and vanA genes can not be determined in S. aureus isolates by PCR. Staphylococcus aureus isolates were found to be susceptible to vancomycin by ADDM and MIC test. In conclusion, S. aureus and CNS are found to be the most isolated species from goat milk in Burdur province. In addition to that, the absence of mecA and vanA genes in the S. aureus isolated from goat milk showed that goat milk does not play a significant role in the spreading of MRSA.

Objective: Detection of sources of outbreaks caused by coagulase-negative Staphylococcus relies on molecular epidemiology methods. Little is known about the genetic diversity of the Staphylococcus epidermidis isolates isolated from various sources in Iran. We assessed the molecular epidemiology of S. epidermidis isolates collected from clinical and nonclinical sources from Tehran counties during 2014 to 2016 using MLVA (multilocus variable number tandem repeat analysis). Methods: One hundred and three clinical and nonclinical S. epidermidis isolates were collected from two hospitals in Tehran. Antibiotic susceptibility testing of isolates was evaluated for cefoxitin, tetracycline, erythromycin, clindamycin, mupirocin, vancomycin and linezolid according to Clinical and Laboratory Standards Institute, as well as prevalence of mecA gene was evaluated by PCR method. In addition, genetic relatedness of isolates was assessed by MLVA method. Results: Resistant rate to cefoxitin, tetracycline, erythromycin, clindamycin and mupirocin were 64, 36, 72, 44 and 23 in all isolates. All clinical and nonclinical isolates were susceptible to linezolid and vancomycin. In all, 49.5 of S. epidermidis isolates were multidrug resistant. Prevalence of mecA was 64. The MLVA profile consists of a series of allele numbers, corresponding to the number of repeats at each variable number tandem repeat locus. The results of MLVA showed 64 types among all 103 isolates. There were 16 MLVA types that were common in two hospitals and 15 MLVA types were existed in various sources of S. epidermidis isolates. The diversity index obtained with MLVA was 0.989 (95 confidence interval 0.984–0.993) for the 103 S. epidermidis isolates. A range of one to six alleles was identified at variable number tandem repeats loci with Simpson’s diversity values between 0.526 and 0.781. Conclusion: Our study demonstrated presence of high molecular diversity among S. epidermidis isolates. In addition, the main conclusion was that some MLVA types can be disseminated over the wards and between the hospitals. In other hand, resistance to various antibiotics in S. epidermidis isolates and prevalence of methicillin-resistant S. epidermidis and multidrug resistant S. epidermidis isolates to be increasing. Copyright s 2019 Wolters Kluwer Health, Inc. All rights reserved.

Objectives Diabetic foot ulcers (DFUs) often lead to hospital admissions, amputations and deaths; however, there is no up-to-date information on microbial isolates from DFUs and no mention of utilization of molecular techniques in Sub-Saharan Africa. We conducted a cross-sectional study among 83 adult patients at a tertiary hospital in Kenya over 12 months. The study aimed to isolate, identify bacteria, their antibiotic susceptibility patterns in active DFUs, and to compare standard microbiological methods versus a real-time PCR commercial kit in the detection of Staphylococcus aureus DNA and methicillin-resistant S. aureus (MRSA) DNA. Results Eighty swabs (94%) were culture-positive; 29% were Gram-positive and 65% were Gram-negative. The main organisms isolated were S. aureus (16%), Escherichia coli (15%), Proteus mirabilis (11%), Klebsiella pneumoniae (7%) and Pseudomonas aeruginosa (7%). The bacterial isolates showed resistance to commonly used antibiotics such as ampicillin, amoxicillin, cefepime, ceftazidime, cefuroxime, clindamycin, erythromycin, piperacillin–tazobactam, tetracycline and trimethoprim–sulphamethoxazole (TMPSMX). Thirty-one percent of the S. aureus isolated and 40% of the Gram-negatives were multi-drug resistant organisms (MDROs). There was a high prevalence of nosocomial bacteria. MRSA were not identified using culture methods but were identified using PCR. PCR was more sensitive but less specific than culture-based methods to identify S. aureus. Electronic supplementary material The online version of this article (10.1186/s13104-019-4278-0) contains supplementary material, which is available to authorized users.

To elucidate the molecular determinants of tetracycline resistance in clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates from the private health sector in KwaZulu-Natal province (KZN), South Africa (SA). Seventy-five clinical MRSA isolates were collected from the private hospital sector in KZN, SA over a one-year period. Susceptibility to antibiotics (tetracycline, doxycycline, minocycline and tigecycline) were determined and tetracycline resistant strains were screened using polymerase chain reaction (PCR) for the presence of four putative tetracycline resistance determinants (tet(K), tet(L), tet(M) and tet(O)). Efflux inhibitors were used to assess the possibility of efflux-mediated resistance.All isolates were mecA gene positive and susceptible to doxycycline, minocycline and tigecycline. Of note, 47 (62.67%) isolates were resistant to tetracycline. Doxycycline exhibited the largest number of intermediate resistance 20 (26.67%) in all the isolates. The tet(M)gene was found in all 47tetracycline-resistant isolates. No tet(L), tet(K) and tet(O) were detected. Efflux inhibitors did not have any significant effect on the sensitivity of tetracycline-resistant isolates suggesting that efflux played a minor role in tetracycline resistance. In conclusion; Tet(M) mainly mediates tetracycline resistance in MRSA in the private health sector in KZN, SA. This report on the prevalence and molecular determinants of tetracycline resistance is the first study on clinical MRSA isolates from the private health sector in SA.

BACKGROUND No study has examined the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia in Korean veterans' hospitals. We investigated the microbiological and clinical epidemiology of S. aureus bacteremia at the central Veterans Health Services (VHS) hospital in Korea. METHODS Patients with S. aureus bacteremia were consecutively enrolled from February to August 2015. Bacteremia was classified as hospital-acquired (HA), community-onset healthcare-associated (COHA), or community-acquired (CA). MRSA bacteremia risk factors were analyzed. Species identification, antimicrobial susceptibility, and presence of luk and tst were tested. Staphylococcal cassette chromosome mec (SCCmec) typing, spa sequence typing agr polymorphism typing, and multilocus sequence typing were performed. Biofilm production and δ-hemolysin activity were measured to determine agr function. RESULTS In total, 60 patients were enrolled (30 HA, 23 COHA, and seven CA bacteremia); 44 (73.3%) had MRSA bacteremia (26 HA, 16 COHA, and two CA). MRSA bacteremia occurred more frequently in non-CA patients and those who had received antibiotic treatment within the past month (P

Amaç: Staphylococcus aureus’un icaA ve icaR genleri üzerinden düzenlediği biyofilm yeteneği, oluşturdukları enfeksiyonlar ile mücadeleyi zorlaştırmaktadır. Bu çalışmada, Lactobacillus acidophilus ve Lactobacillus casei’nin, metisilin duyarlı (MSSA) ve metisilin dirençli (MRSA) S. aureus suşlarının icaA ve icaR gen ekspresyonlarına etkisinin in-vitro olarak incelenmesi amaçlanmıştır. Gereç ve Yöntem: IcaA ve icaR gen ekspresyonlarının kontrolü için 6 tüp hazırlandı. 37oC’da %5 CO2’li ortamda inkübe edildi. İnkübasyonun 6., 12., ve 24. saatinde RNA izolasyonları yapıldı. cDNA sentezi sonrasında,icaA, icaR ve 16SrRNA genlerine spesifik primerler ile real-time PCR’la çalışıldı. Delta delta Ct yöntemine göre sonuçlar analiz edildi. Bulgular: S. aureus ATCC 43300 (MRSA) ve S. aureus ATCC 29213 (MSSA) icaA gen ve icaR ekspresyonları, L. acidophilus ve L. casei ile karşılaşma sonrası sırasıyla down regülasyon ve upregulasyon göstermiştir. 12. saat ve 24. saatte saptanan icaA ve icaR gen ekspresyon seviyelerinin hem MRSA hem de MSSA suşlarında benzer olduğu gözlenmiştir. Öneri: Sonuç olarak, çalışmamız, probiyotik etkili L. acidophilus ve L. casei suşlarının S. aureus suşlarının biyofilm etkinliklerini icaA ve icaR gen ekspresyonlarını real-time PCR yöntemi ile araştıran ilk çalışmadır. L. acidophilus ve L. casei’nin in-vitro ortamda MRSA ve MSSA suşlarını etkileyerek icaA ve icaR gen ekspresyonlarını değiştirebildikleri saptanmıştır. Probiyotik etkili bu suşların antibiyofilm özelliklerinin S. aureus enfeksiyonlarına karşı yeni bir mücadele seçeneği olabileceği düşünülmektedir., Aim: Staphylococcus aureus’s biofilm ability which control via icaA and icaR gene is a serious problem in the treatment of infections. Aim of this study was to investigate in-vitro effects of important probiotic L. acidophilus and L. casei on the icaA and icaR genes expressions of the MRSA and MSSA strains. Materials and Methods: In this study, to determine the icaA and icaR gene expressions, 6 tubes in probiotics were prepared. Incubated at 37°C in 5% CO2 medium. RNA isolations were performed at the 6th, 12th, and 24th hours of incubation. After cDNA synthesis, real-time PCR with primers specific for icaA, icaR and 16S rRNA genes were studied. The results were calculated with delta delta Ct method. Results: S. aureus ATCC 43300 (MRSA) and S. aureus ATCC 29213 (MSSA) icaA gene and icaR gene expressions showed down regulation and upregulation respectively after encountering L. acidophilus and L. casei. The icaA and icaR gene expression ratios determined at 12 hours and 24 hours were found to be similar in both MRSA and MSSA strains. Conclusion: This study was the first study to investigate effect of L. acidophilus and L. casei strains on biofilm gene expression of the S. aureus strains by the real-time PCR method. It was determined that L. acidophilus and L. casei were able to alter icaA and icaR gene expression by affecting the MRSA and MSSA strains in-vitro. We believe that the antibiotic properties of these probiotic strains may be a new treatment option against S. aureus biofilm infections.

[EN] Staphylococcus aureus is acknowledged as one of the important pathogens isolated from humans and animals. However, the S. aureus causing severe respiratory diseases in rabbits have not been well characterised. A S. aureus named FZHW001, isolated from the lungs of dead rabbits with severe respiratory disease, was characterised by artificial infection of rabbits, detection of virulence factors, multi-locus sequencing typing and antimicrobial susceptibility test. The FZHW001 infected rabbits showed identical respiratory symptoms to those of naturally infected ones, and the isolate could spread through directed contact among rabbits. The isolate was typed into clonal complex 121 and carried 7 of 13 tested virulence factors. Furthermore, the isolate was identified to be methicillin-susceptible S. aureus and was susceptible to 7 of 12 tested antibiotics. This study first describes the characteristics of S. aureus isolated from rabbits causing severe respiratory disease, which will help in further understanding the pathogenic mechanisms of S. aureus in rabbits., This work was supported by the Outstanding Youth Fund of Fujian Academy of Agricultural Sciences (JC2018-1) and National Rabbit Industry Technology System of People’s Republic of China (CARS-43-G-5).