scholarly journals Reliability of mecA in Predicting Phenotypic Susceptibilities of Coagulase-Negative Staphylococci and Staphylococcus aureus

2020 ◽  
Vol 7 (12) ◽  
Author(s):  
Manon C Williams ◽  
Samuel R Dominguez ◽  
Andrea Prinzi ◽  
Kayla Lee ◽  
Sarah K Parker

Abstract The mecA gene is commonly used to identify resistance in Staphylococcus aureus, but historically is not used for coagulase-negative staphylococci (CoNS). Analysis of 412 staphylococcal blood cultures (2014–2018) revealed that the absence of mecA had high concordance (100%) with oxacillin susceptibility for S. aureus and CoNS alike.

2004 ◽  
Vol 25 (8) ◽  
pp. 685-689 ◽  
Author(s):  
Florian Daxboeck ◽  
Werner Rabitsch ◽  
Alexander Blacky ◽  
Maria Stadler ◽  
Paul A. Kyrle ◽  
...  

AbstractObjective:To assess the influence of prophylactic selective bowel decontamination (SBD) on the spectrum of microbes causing bloodstream infection (BSI).Design:The microbes causing BSI in neutropenic patients of a hematologic ward (HW) and a bone marrow transplantation unit (BMTU), respectively, were compared by retrospective analysis of blood culture results from January 1996 to June 2003.Setting:A 30-bed HW (no SBD) and a BMTU including a 7-bed normal care ward and an 8-bed intensive care unit (SBD used) of a 2,200-bed university teaching hospital.Results:The overall incidences of bacteremia in the HW and the BMTU were similar (72.6 vs 70.6 episodes per 1,000 admissions; P = .8). Two hundred twenty episodes of BSI were recorded in 164 neutropenic patients of the HW and 153 episodes in 127 neutropenic patients of the BMTU. Enterobacteriaceae (OR, 3.14; CI95, 1.67–5.97; P = .0002) and Streptococcus species (OR, 2.04; CI95, 1.14–3.70; P = .015) were observed more frequently in HW patients and coagulase-negative staphylococci more frequently in BMTU patients (OR, 0.15; CI95, 0.09–0.26; P< .00001). No statistically significant differences were found for gram-negative nonfermentative bacilli (P = .53), Staphylococcus aureus (P = .21), Enterococcus species (P = .48), anaerobic bacteria (P = .1), or fungi (P = .50).Conclusions:SBD did not lead to a significant reduction in the incidence of bacteremia, but significant changes in microbes recovered from blood cultures were observed. SBD should be considered when empiric antimicrobial therapy is prescribed for suspected BSI.


2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
S Habjan ◽  
B Erzen ◽  
M Miklic ◽  
A Skarlovnik

Abstract Background Catheter-related right atrial thrombosis is a rare, but potentially life threatening complication in patients with central venous catheters (CVCs). Echocardiography is an indispensable tool in the diagnosis of right atrial thrombosis. We present a case of a young man with lymphoma, Staphylococcus aureus sepsis and a peripherally inserted central catheter (PICC) who had a septic thrombus in the right atrium. Case summary A 23-year-old male patient with recently diagnosed Hodgkin’s lymphoma had an inserted PICC for the purpose of chemotherapy application. Three days after the first chemotherapy application a thrombosis of the cephalic and subclavian veins at the site of PICC was found. The PICC was removed and the patient was treated with therapeutic doses of dalteparin. A day after the discovery of thrombosis, the patient became clinically septic, with high inflammatory markers and Staphylococcus aureus was isolated from his blood cultures. He was promptly treated with flucloxacillin. Due to pain in his left knee, a knee puncture was performed, and Staphylococcus aureus was isolated also from the knee synovial fluid. A transthoracic echocardiography revealed a 2.8 x 2.8 cm sessile thrombus on the lateral wall of the right atrium. There were no vegetations on the tricuspid or other valves. Due to increasing pain in his left knee and an increase in inflammatory markers a synovectomy was performed. After the operation the clinical status improved and the inflammatory parameters decreased. A magnetic resonance imaging of the heart was performed, which confirmed the thrombus described by echocardiography and excluded the presence of abscesses. All the time the patient was treated in the intensive care unit with standard heparin, flucloxacillin, and piperacillin/tazobactam due to neutropenia. The inflammatory markers slowly decreased and all further blood cultures were negative. Follow-up echocardiography after 16 days of antibiotic and anticoagulant therapy revealed that the mass in the right atrium, attached on the lateral atrium wall, was slightly smaller than before. The mass was centrally un-echogenic with echogenic cover, appearing as a partial regression of the septic thrombus with a central colliquation. The heart valves remained free of vegetations. There was a minor pericardial effusion, with no signs of constriction. Due to improved clinical status the patient was able to start with chemotherapy again after a pause of three weeks. Conclusion The patient had three important risk factors for thrombosis: PICC, sepsis and malignancy. Echocardiography is an important tool for mass diagnosis and the exclusion of vegetations in a septic patient. Often there is a need for further specification of the mass etiology or for the exclusion of other pathology, like abscesses in our case. Magnetic resonance is an important tool that can complement the echocardiographic examination. Abstract P1498 Figure. Right atrial thrombus


Pathogens ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 381
Author(s):  
Wedad Ahmed ◽  
Heinrich Neubauer ◽  
Herbert Tomaso ◽  
Fatma Ibrahim El Hofy ◽  
Stefan Monecke ◽  
...  

The aim of this study was to characterize staphylococci and streptococci in milk from Egyptian bovides. In total, 50 milk samples were collected from localities in the Nile Delta region of Egypt. Isolates were cultivated, identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic susceptibility testing was performed by the broth microdilution method. PCR amplifications were carried out, targeting resistance-associated genes. Thirty-eight Staphylococcus isolates and six Streptococcus isolates could be cultivated. Staphylococcus aureus isolates revealed a high resistance rate to penicillin, ampicillin, clindamycin, and erythromycin. The mecA gene defining methicillin-resistant Staphylococcus aureus, erm(C) and aac-aphD genes was found in 87.5% of each. Coagulase-negative staphylococci showed a high prevalence of mecA, blaZ and tetK genes. Other resistance-associated genes were found. All Streptococcus dysgalactiae isolates carried blaZ, erm(A), erm(B), erm(C) and lnuA genes, while Streptococcus suis harbored erm(C), aphA-3, tetL and tetM genes, additionally. In Streptococcus gallolyticus, most of these genes were found. The Streptococcus agalactiae isolate harbored blaZ, erm(B), erm(C), lnuA, tetK, tetL and tetM genes. Streptococcus agalactiae isolate was analyzed by DNA microarray analysis. It was determined as sequence type 14, belonging to clonal complex 19 and represented capsule type VI. Pilus and cell wall protein genes, pavA, cadD and emrB/qacA genes were identified by microarray analysis.


1984 ◽  
Vol 5 (3) ◽  
pp. 142-143 ◽  
Author(s):  
D.J. Flournoy

Coagulase-negative staphylococci (CONS) have only recently gained notoriety as pathogens. Several reports have established their pathogenicity in bacterial endocarditis, prosthetic heart valve endocarditis, intraventricular shunts for treatment of hydrocephalus and intravenous catheters. One difficult decision for physicians is determining whether a particular CONS isolate is pathogenic or contaminant. The differentiation of pathogenic and contaminant CONS has recently been noted, but further studies are needed to aid in this differentiation. Data on antimicrobial susceptibilities of positive blood culture isolates were recently compiled at this institution. This report compares antimicrobial susceptibilities of pathogenic and contaminant CONS and Staphylococcus aureus blood culture isolates from 1961-1981 at this institution.


Folia Medica ◽  
2019 ◽  
Vol 61 (4) ◽  
pp. 559-565
Author(s):  
Raina T. Gergova ◽  
Virna-Maria S. Tsitou ◽  
Ivan G. Mitov

Background: Invasive infections caused by methicillin resistant Staphylococcus aureus and coagulase-negative staphylococci (MRSA/MRSCoN) require fast, adequate treatment.&nbsp; The aim of this study was to develop a faster protocol for direct detection of MRSA/MRSCoN in blood cultures and in abscess punctures based on mecA and species specific identification of S. aureus by polymerase-chain reaction (PCR). Materials and methods: We examined 77 growth-positive BACTEC blood cultures and 50 abscess punctures by routine microbiological assay and simultaneous PCR detection of MRSA/MRSCoN. The speci&#64257;city of the PCR was evaluated by using DNA from another 15 microbial species for negative controls. We determined the minimum inhibitory concentration (MIC) of oxacillin, vancomycin, tigecycline, linezolid, levofloxacin, clindamycin, and erythromycin against the S. aureus isolates using the E-test.&nbsp; Results: In the blood cultures, the two methods detected 39.3% of MRSA, and 93.9% of MRCoNS. In the punctures, the PCR assay identified 20.9% of MRSA and 79.2% of MSSA. In the puncture cases, there were three PCR MRSA positive and culture negative samples. Screening for susceptibility to 14 antimicrobial agents demonstrated significantly higher (p<0.05) methicillin resistance in blood culture isolates than in the puncture ones (39.3% and 20.0%, respectively).&nbsp; Conclusion: The new PCR protocol was very fast and specific. It was more sensitive in detecting MRSA from abscess punctures than the routine microbiological techniques. This protocol will speed up the right choice of empirical therapy, which is extremely important for saving patients&rsquo; lives.


2019 ◽  
Vol 12 (11) ◽  
pp. 1760-1768 ◽  
Author(s):  
Nimita Venugopal ◽  
Susweta Mitra ◽  
Rituparna Tewari ◽  
Feroze Ganaie ◽  
Rajeswari Shome ◽  
...  

Background and Aim: Methicillin-resistant staphylococci are among the emerging pathogens which have become a threat to both human and animal health. The present investigation intended to examine the occurrence and the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) recovered from cattle, its handlers, and their environment. Materials and Methods: A total of 666 specimens were subjected to culture method and genus-specific polymerase chain reaction (PCR) for the identification of Staphylococcus. Methicillin resistance was substantiated by PCR identification of mecA and mecC resistance determinants. Species-specific identification of mecA positive isolates was conducted by multiplex PCR. The unidentified species were deciphered by 16S rRNA gene sequencing approach. The mecA positive isolates were further characterized by staphylococcal cassette chromosome mec (SCCmec) typing and multilocus sequence typing (MLST). Results: Duplex PCR identified 728 Staphylococcus isolates, of which 66 (9%) were positive for mecA gene. MRSA constituted 24% of the total mecA positive isolates. Among MRCoNS, Staphylococcus epidermidis (42%), and Staphylococcus haemolyticus (11%) were the most common species identified. Overall, 47% of the mecA positive isolates belonged to SCCmec type V. MLST analysis showed eight different sequence types (STs) among MRSA isolates of which five were novel STs. Among methicillin-resistant S. epidermidis, 19 different STs were found, of which nine novel STs were detected. Conclusion: The increase in the prevalence of mecA positive staphylococci, especially MRCoNS in cattle is a great concern in view of their transmission potential. Hence, continuous monitoring and molecular characterization of methicillin-resistant staphylococci should be elucidated in human and animal sectors so as to prevent the spread of these resistant pathogens.


Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 676
Author(s):  
Miryam Bonvegna ◽  
Elena Grego ◽  
Bruno Sona ◽  
Maria Cristina Stella ◽  
Patrizia Nebbia ◽  
...  

Swine farming as a source of methicillin-resistant Staphylococcus aureus (MRSA) has been well documented. Methicillin-resistant coagulase-negative staphylococci (MRCoNS) have been less studied, but their importance as pathogens is increasing. MRCoNS are indeed considered relevant nosocomial pathogens; identifying putative sources of MRCoNS is thus gaining importance to prevent human health hazards. In the present study, we investigated MRSA and MRCoNS in animals and environment in five pigsties in a high farm-density area of northwestern Italy. Farms were three intensive, one intensive with antibiotic-free finishing, and one organic. We tested nasal swabs from 195 animals and 26 environmental samples from three production phases: post-weaning, finishing and female breeders. Phenotypic tests, including MALDI-TOF MS, were used for the identification of Staphylococcus species; PCR and nucleotide sequencing confirmed resistance and bacterial species. MRCoNS were recovered in 64.5% of nasal swabs, in all farms and animal categories, while MRSA was detected only in one post-weaning sample in one farm. The lowest prevalence of MRCoNS was detected in pigs from the organic farm and in the finishing of the antibiotic-free farm. MRCoNS were mainly Staphylococcus sciuri, but we also recovered S. pasteuri, S. haemolyticus, S. cohnii, S. equorum and S. xylosus. Fifteen environmental samples were positive for MRCoNS, which were mainly S. sciuri; no MRSA was found in the farms’ environment. The analyses of the mecA gene and the PBP2-a protein highlighted the same mecA fragment in strains of S. aureus, S. sciuri and S. haemolyticus. Our results show the emergence of MRCoNS carrying the mecA gene in swine farms. Moreover, they suggest that this gene might be horizontally transferred from MRCoNS to bacterial species more relevant for human health, such as S. aureus.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5177-5177
Author(s):  
Ghazi S. Alotaibi ◽  
Irwindeep Sandhu ◽  
Joseph M. Brandwein ◽  
Lalit Saini

Abstract INTRODUCTION: The pathogenesis of infective endocarditis (IE) , a typical biofilm-associated infectious disease frequently caused by commensal or pathogenic bacteria, is mainly attributed to the formation of septic vegetations, which are fibrin-platelet complexes embedded with bacteria on heart valves detected by echocardiography. Patients with acute myeloid leukemia (AML) are prone to neutropenia, immunosuppression and central venous catheters leading to high rates of bacteremia. It has been postulated that despite high rates of bacteremia, patients with AML undergoing intensive chemotherapy are only rarely able to form vegetations due the frequent thrombocytopenia associated with such treatment (McCormick 2002). Here, we sought to determine the rate of echocardiographic detection of IE in patients with AML and chemotherapy induced thrombocytopenia . METHODS: To assess the yield of echocardiography, we conducted a retrospective, single center, analysis of patients with AML who underwent treatment using anthracycline or fludarabine induction and intermediate/high dose cytarabine based consolidation. At all time points, patients with febrile neutropenia were empirically treated with piperacillin/tazobactam ± aminoglycosides and underwent appropriate investigations including blood cultures. Cultures were drawn every 24 to 48 hours with fevers and daily, if positive, till culture clearance. Patients with positive blood cultures for organisms associated with IE underwent an echocardiogram as standard of care. RESULTS: From January 2010 to January 2018, 296 patients underwent curative intent chemotherapy for treatment of acute myeloid leukemia (AML) at the University of Alberta Hospital, Edmonton, Canada. The median age of all patients was 56.7 years (IQR: 44-64) and 40.2% were females. During the induction or consolidation chemotherapy , 53 echocardiogram were done to investigate 53 episodes of bacteremia in 50 patients (16.9%) who had organisms associated with IE (Table 1). Two echocardiograms were done to investigate possible culture negative IE based upon clinical suspicion. Transesophageal echocardiogram were utilized in 19 patients (36%) while transthoracic echocardiogram were done in 34 patients (64%). The median platelets count on the day of the echocardiogram was 23 x109/L (IQR: 14-38). Viridans Group Streptococci and Staphylococcus aureus were the most frequent isolates cultured in the blood in 36% and 16% of cases, respectively. The median duration of bacteremia was 1 day (IQR 1-2). Three (5.6%) patients had echocardiographic findings suggestive of IE based on a positive transesophageal study (n=2) or transthoracic study (n=1). Among these, two were secondary to Enterococcus bacteria and involved the mitral valve and the third was secondary to a non-HACEK gram-negative bacteria leading to tricuspid valve involvement . CONCLUSION: This study is the first to suggest that despite the high prevalence of Viridans Group Streptococci and Staphylococcusaureus in patients with AML undergoing chemotherapy, echocardiographic findings of IE in these patients are rare, with the notable exception of Enterococcal and Non-HACEK gram negative organisms. In contrast, in the general population, Viridans Group Streptococci and Staphylococcus aureus and bacteremia are associated with IE in 20% and 63% %, respectively (Westling 2009, Rasmussen 2011). The low incidence in our cohort may be attributed to impaired fibrin-platelet deposition in these patients with inability to mount a vegetation response, or the early initiation of broad spectrum antibiotics. Given these findings, the value of routine echocardiography should be questioned in patients with AML without other clinical features of IE. Disclosures Sandhu: Bioverativ: Honoraria; Celgene: Honoraria; Novartis: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Brandwein:Pfizer: Consultancy; Celgene: Consultancy; Boehringer Ingelheim: Consultancy, Research Funding; Novartis: Consultancy; Lundbeck: Consultancy.


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