Archive for July 6, 2017

Coagulase-negative staphylococci.

Clin Microbiol Rev. October 2014 V.27 N.4 P.870-926.                         

Becker K1, Heilmann C2, Peters G2.

Author information

1 Institute of Medical Microbiology, University Hospital Münster, Münster, Germany

2 Institute of Medical Microbiology, University Hospital Münster, Münster, Germany.


The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic.

Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns.

While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis.

In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections.

This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies.

Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important.

Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides.



July 6, 2017 at 9:55 pm

EDITORIAL – Estafilococos coagulasa negativos: el enemigo silente

Revista Argentina de Microbiología (2007) 39: 1-3


Departamento de Microbiología, Instituto de Investigaciones Médicas Alfredo Lanari, Facultad de Medicina, Universidad de Buenos Aires. Avda. Combatientes de Malvinas 3150 (C1427ARO) Ciudad Autónoma de Buenos Aires, Argentina.

Correspondencia. E-mail:

Los estafilococos coagulasa negativos (ECN) o estafilococos coagulasa-negativa (ambas formas de expresión son correctas) son parte de la microbiota residente de humanos y animales.

Se encuentran alojados en forma preferencial según las distintas especies –ya más de treinta– en las diferentes zonas de la piel y de las mucosas….


July 6, 2017 at 9:22 pm

Staphylococcus haemolyticus – an emerging threat in the twilight of the antibiotics age

Microbiology (2015), 161, 2061–2068

Tomasz Czekaj, Marcin Ciszewski and Eligia M. Szewczyk

Department of Pharmaceutical Microbiology and Microbiological Diagnostics, Medical University

of Ło´dz´, Pomorska 137, 90-235 Ło´dz´, Poland

Staphylococcus haemolyticus is one of the most frequent aetiological factors of staphylococcal infections. This species seems to lack the important virulence attributes described in other staphylococci.

However, studies have shown that the presence of various enzymes, cytolysins and surface substances affects the virulence of S. haemolyticus. Nevertheless, none of them has been identified as crucial and determinative.

Despite this, S. haemolyticus is, after Staphylococcus epidermidis, the second most frequently isolated coagulase-negative staphylococcus from clinical cases, notably from blood infections, including sepsis.

This raises the question of what is the reason for the increasing clinical significance of S. haemolyticus?

The most important factor might be the ability to acquire multiresistance against available antimicrobial agents, even glycopeptides.

The unusual genome plasticity of S. haemolyticus strains manifested by a large number of insertion sequences and identified SNPs might contribute to its acquisition of antibiotic resistance.

Interspecies transfer of SCCmec cassettes suggests that S. haemolyticus might also be the reservoir of resistance genes for other staphylococci, including Staphylococcus aureus.

Taking into consideration the great adaptability and the ability to survive in the hospital environment, especially on medical devices, S. haemolyticus becomes a crucial factor in nosocomial infections caused by multiresistant staphylococci.


July 6, 2017 at 9:21 pm

Estudio molecular de Staphylococcus haemolyticus resistente a meticilina en un hospital de México

Rev Invest Clin 2006; 58 (6): 580-585

Natividad Castro,* María Salomé Loaiza-Loeza,* Amparo Calderón-Navarro,** Alejandro Sánchez,*** Jesús Silva-Sánchez***

* Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero.

** Hospital General de Acapulco, Secretaría de Salud de Acapulco.

*** Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública.


Caracterizar molecularmente los aislamientos clínicos de Staphylococcus haemolyticus resistentes a meticilina (SHRM) obtenidos de pacientes del Hospital General de Acapulco, Guerrero, México. Métodos.

Se incluyeron 63 aislamientos de Staphylococcus ssp., colectados durante el periodo de septiembre de 2000 a octubre de 2002.

La susceptibilidad antimicrobiana se determinó por el método de difusión en disco y la presencia del gen mecA se detectó por la técnica de reacción en cadena de la polimerasa (PCR).

Los aislamientos de SHRM fueron caracterizados por electroforesis en gel por campos pulsados (PFGE).


La frecuencia de S. haemolyticus correspondió al 28.5% (18 de 63 aislamientos clínicos), todos los aislamientos fueron resistentes a meticilina confirmándose el genotipo mecA. Se identificó una clona mayoritaria A con ocho subtipos. Esta clona fue identificada durante 20 meses, principalmente de los servicios de cirugía en 55%, seguido de pediatría en 27.7%.


La permanencia de S. haemolyticus resistente a meticilina como patógeno nosocomial en este hospital sugiere establecer programas de control para disminuir la prevalencia de este patógeno multirresistente


July 6, 2017 at 9:19 pm

Staphylococcus coagulasa-negativa clínicamente significativos. Especies más frecuentes y factores de virulencia

Rev Chilena Infectol 2013; 30 (5): 480-488

Norma Fariña, Letizia Carpinelli, Margarita Samudio, Rosa Guillén, Florentina Laspina, Ramona Sanabria, Sonia Abente, Ladis Rodas, Pedro González y Herminia M. de Kaspar

Instituto de Investigaciones en Ciencias de la Salud Asunción, Paraguay. (NF, LC, MS, RG, FL, RS, SA, HM). Laboratorio San Roque. Asunción, Paraguay (LR, PG).


Coagulase-negative staphylococci have emerged as responsible for a large number of infections. However, it is often difficult to assess its pathogenic role or to discard it as a contaminant.


The goal of this study was to identify clinically significant coagulase-negative staphylococci to the species level and their virulence factors. Isolates came from patients consulting at the San Roque Laboratory from 2009 to 2011.

Material and Methods

Species identification was performed by De Paulis et al simplified method. Production of biofilm, hemolysins, lipases, lecithinases and DNase were determined by conventional methods; methicillin-resistance by diffusion method and mecA and Panton-Valentine genes, by multiplex PCR.


Out of 64 isolates, 40.6% were S. epidermidis; 20.3%, S. haemolyticus, and 15.6%, S. lugdunensis. Biofilm production was detected in 73.1% of S. epidermidis, 53.8% of S. haemolyticus and 40% of S. lugdunensis. mecA gene was identified in 69.2% of S. epidermidis, 92.3% of S. haemolyticus and none of S. lugdunensis. 83% of mecA (+) S. epidermidis isolates were biofilm producers as compared to 50% of the mecA (-).


The frequency of S. lugdunensis, the most virulent coagulase-negative staphylococci species, was relatively high. The main virulence factor in S. epidermidis was biofilm production, being higher in those resistant to methicillin.


July 6, 2017 at 9:17 pm

Validation of the diagnosis ‘prosthetic joint infection’ in the Danish Hip Arthroplasty Register

Rev. Bone & Joint Journal 2016 Vol. 98 N.3 P.320-325       

H. Gundtoft, A. B. Pedersen, H. C. Schønheyder, S. Overgaard



The purpose of this study was to validate the diagnosis of periprosthetic joint infection (PJI) in the Danish Hip Arthroplasty Register (DHR).

Patients and Methods

We identified a cohort of patients from the DHR who had undergone primary total hip arthroplasty (THA) since 1 January 2005 and followed them until first-time revision, death, emigration or until 31 December 2012. Revision for PJI, as registered in the DHR, was validated against a benchmark which included information from microbiology databases, prescription registers, clinical biochemistry registers and clinical records. We estimated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for PJI in the DHR alone and in the DHR when combined with microbiology databases.


In total, 1382 of the 37 826 primary THAs in the DHR were registered as having been revised for any cause once 26 patients with errors in registration had been excluded: 232 of these were for PJI. For this group, the sensitivity was 67%, specificity 95%, PPV 77%, and NPV 92%. Combining the data from the DHR with those from microbiology databases increased the sensitivity to 90% and also improved specificity (100%), PPV (98%) and NPV (98%).


Only two thirds of revisions for PJI were captured in the DHR and only 77% of the PJI reported to the DHR could be confirmed to be infected. Take home message: combining the data from the DHR with those from microbiology databases substantially improved the validity of the diagnosis of PJI and should enable future register-based studies.



July 6, 2017 at 8:46 am

Managing uncertainty – a qualitative study of surgeons’ decision-making for one-stage and two-stage revision surgery for prosthetic hip joint infection

Rev. BMC Musculoskeletal Disorders 2017 V.18 N.4 P.154

Andrew J. Moore, Ashley W. Blom, Michael R. Whitehouse and Rachael Gooberman-Hill

1 School of Clinical Sciences, University of Bristol, Bristol, UK.

2 School of Clinical Sciences, University of Bristol, Bristol, UK.



Approximately 88,000 primary hip replacements are performed in England and Wales each year. Around 1% go on to develop deep prosthetic joint infection.

Between one-stage and two-stage revision arthroplasty best treatment options remain unclear.

Our aims were to characterise consultant orthopaedic surgeons’ decisions about performing either one-stage or two-stage revision surgery for patients with deep prosthetic infection (PJI) after hip arthroplasty, and to identify whether a randomised trial comparing one-stage with two-stage revision would be feasible.


Semi-structured interviews were conducted with 12 consultant surgeons who perform revision surgery for PJI after hip arthroplasty at 5 high-volume National Health Service (NHS) orthopaedic departments in England and Wales. Surgeons were interviewed before the development of a multicentre randomised controlled trial. Data were analysed using a thematic approach.


There is no single standardised surgical intervention for the treatment of PJI. Surgeons balance multiple factors when choosing a surgical strategy which include multiple patient-related factors, their own knowledge and expertise, available infrastructure and the infecting organism. Surgeons questioned whether it was appropriate that the two-stage revision remained the best treatment, and some surgeons’ willingness to consider more one-stage revisions had increased over recent years and were influenced by growing evidence showing equivalence between surgical techniques, and local observations of successful one-stage revisions. Custom-made articulating spacers was a practice that enabled uncertainty to be managed in the absence of definitive evidence about the superiority of one surgical technique over the other. Surgeons highlighted the need for research evidence to inform practice and thought that a randomised trial to compare treatments was needed. Most surgeons thought that patients who they treated would be eligible for trial participation in instances where there was uncertainty about the best treatment option.


Surgeons highlighted the need for evidence to support their choice of revision. Some surgeons’ willingness to consider one-stage revision for infection had increased over time, largely influenced by evidence of successful one-stage revisions.

Custom-made articulating spacers also enabled surgeons to manage uncertainty about the superiority of surgical techniques.

Surgeons thought that a prospective randomised controlled trial comparing one-stage with two-stage joint replacement is needed and that randomisation would be feasible.


July 6, 2017 at 8:45 am

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