Staphylococcus aureus with reduced susceptibility to vancomycin isolated from a patient with fatal bacteremia.

A Staphylococcus aureus isolate with reduced susceptibility to vancomycin was obtained from a dialysis patient with a fatal case of bacteremia. Comparison of the isolate with two methicillin-resistant S. aureus (MRSA) isolated obtained from the same patient 4 months earlier suggests that the S. aureus with reduced susceptibility to vancomycin emerged from the MRSA strain with which the patient was infected. Atypical phenotypic characteristics, including weak or negative latex-agglutination test results, weak or negative-slide coagulase test results, heterogeneous morphologic features, slow rate of growth, and vancomycin susceptibility (by disk diffusion test) were observed

Epidemiological analysis of methicillin-resistant Staphylococcus aureus isolates from adult patients with cystic fibrosis

Using pulsed-field gel electrophoresis, we genotyped 21 methicillin-resistant Staphylococcus aureus isolates from patients attending an adult cystic fibrosis unit. Eleven patients exhibited pulsotypes related to 2 locally endemic strains. Eleven chronically colonized patients were assessed over a period of up to 2 years, and all demonstrated a retention of strain type

Vancomycin-resistant enterococci outside the health-care setting: prevalence, sources, and public health implications.

Although nosocomial acquisition and subsequent colonization of vancomycin-resistant enterococci (VRE), an emerging international threat to public health, has been emphasized in the United States, colonization among nonhospitalized persons has been infrequently documented. In contrast, in Europe, colonization appears to occur frequently in persons outside the health-care setting. An important factor associated with VRE in the community in Europe has been avoparcin, a glycopeptide antimicrobial drug used for years in many European nations at subtherapeutic doses as a growth promoter in food-producing animals. In Europe, evidence suggests that foodborne VRE may cause human colonization. Although avoparcin has never been approved for use in the United States, undetected community VRE transmission may be occurring at low levels. Further studies of community transmission of VRE in the United States are urgently needed. If transmission with VRE from unrecognized community sources can be identified and controlled, increased incidence of colonization and infection among hospitalized patients may be prevented

Dynamics of bovine intramammary infections due to coagulase-negative staphylococci on four farms

The objectives of this study were to compare the impact of different coagulase-negative species (CNS) on udder health measured in terms of individual quarter milk somatic cell count (SCC) and duration of intramammary infection, and to get some insight into most likely routes of infection for different CNS species. This longitudinal observational study was performed on four farms that were sampled at 4-week intervals for a total of 12 visits each. Quarters infected with CNS were followed through time with milk samples being submitted for bacteriological culture and SCC determination. PCR amplification of the internal transcribed spacer region and sequencing of the sodA and rpoB genes were used for species allocation. Pulsed-field gel electrophoresis (PFGE) was performed to assess strain identity. The percentage of quarters affected per farm varied between 6 and 35%, with the most frequently isolated CNS species being Staphylococcus epidermidis, followed by Staph. simulans, Staph. chromogenes and Staph. haemolyticus. It was possible to follow 111 intramammary infections due to CNS through time. Duration of infection had a mean of 188 d and was not significantly different between CNS species. Geometric mean quarter SCC overall was 132 000 cells/ml and was also not significantly different between CNS species. Despite the possibility of a different epidemiology of infection, the impact in terms of udder health seems to be similar for different CNS species

Molecular epidemiology of clinical isolates of Pseudomonas aeruginosa isolated from horses in Ireland

Clinical isolates (n = 63) of Pseudomonas aeruginosa obtained from various sites in 63 horses were compared using ERIC2 RAPD PCR to determine their genetic relatedness. Resulting banding patterns (n = 24 genotypes) showed a high degree of genetic heterogeneity amongst all isolates examined, indicating a relative non-clonal relationship between isolates from these patients, employing this genotyping technique. This study characterised 63 clinical isolates into 24 distinct genotypes, with the largest cluster (genotype E) accounting for 10/63 (15.9%) of the isolates. ERIC2 RAPD PCR proved to be a highly discriminatory molecular typing tool of P. aeruginosa in isolates recovered from horses. With the adoption of several controls to aid reproducibility, this technique may be useful as an alternative to PFGE, particularly in epidemiological investigations of outbreaks where speed may be a significant parameter. This is the first report of clonal heterogeneity amongst P. aeruginosa from horses and demonstrated that ERIC RAPD PCR is a rapid method for the examination of this species in horses, which may be useful in outbreak analysis

Vancomycin in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection: End of an era?

Infection with meticillin-resistant Staphylococcus aureus (MRSA) continues to have significant morbidity and mortality. Vancomycin, which has been the mainstay of treatment of invasive MRSA infections, has several drawbacks related to its pharmacological properties as well as varying degrees of emerging resistance. These resistant subpopulations are difficult to detect, making therapy with vancomycin less reliable. The newer agents such as linezolid, daptomycin, ceftaroline, and the newer glycopeptides telavancin and oritavancin are useful alternatives that could potentially replace vancomycin in the treatment of certain conditions. By summarising the discussions that took place at the III MRSA Consensus Conference in relation to the current place of vancomycin in therapy and the potential of the newer agents to replace vancomycin, this review focuses on the challenges faced by the laboratory and by clinicians in the diagnosis and treatment of MRSA infections.No Full Tex

The speciation and genotyping of Cronobacter isolates from hospitalised patients

The World Health Organization (WHO) has recognised all Cronobacter species as human pathogens. Among premature neonates and immunocompromised infants, these infections can be life-threatening, with clinical presentations of septicaemia, meningitis and necrotising enterocolitis. The neurological sequelae can be permanent and the mortality rate as high as 40 – 80 %. Despite the highlighted issues of neonatal infections, the majority of Cronobacter infections are in the elderly population suffering from serious underlying disease or malignancy and include wound and urinary tract infections, osteomyelitis, bacteraemia and septicaemia. However, no age profiling studies have speciated or genotyped the Cronobacter isolates. A clinical collection of 51 Cronobacter strains from two hospitals were speciated and genotyped using 7-loci multilocus sequence typing (MLST), rpoB gene sequence analysis, O-antigen typing and pulsed- field gel electrophoresis (PFGE). The isolates were predominated by C. sakazakii sequence type 4 (63 %, 32/51) and C. malonaticus sequence type 7 (33 %, 17/51). These had been isolated from throat and sputum samples of all age groups, as well as recal and faecal swabs. There was no apparent relatedness between the age of the patient and the Cronobacter species isolated. Despite the high clonality of Cronobacter , PFGE profiles differentiated strains across the sequence types into 15 pulsotypes. There was almost complete agreement between O-antigen typing and rpoB gene sequence analysis and MLST profiling. This study shows the value of applying MLST to bacterial population studies with strains from two patient cohorts, combined with PFGE for further discrimination of strains

Prospective study of the feasibility of point-of-care testing strategy for carbapenem-resistant organism detection

Background/aims: In an investigator-initiated, prospective study, we evaluated the feasibility of a five-gene sequence point-of-care (POC) testing strategy (Xpert CARBA-R Assay, Cepheid Inc., Sunnyvale, CA, USA), compared to reference laboratory PCR (48 – 72 hours turnaround time, two gene sequences), in patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and in a hospital outbreak investigation. Methods: After informed consent, patients undergoing ERCP (September 2015 – April 2016, n = 191) at Mayo Clinic and potential hospital contacts (n = 9) of an index carbapenem-resistant organism (CRO)-positive inpatient were included. Two rectal swabs, one each for reference and POC assays were obtained. The Xpert CARBA-R Assay enables qualitative rapid detection of five beta-lactamase gene sequences associated with carbapenem-non-susceptibility in Gram-negative bacteria. Feasibility parameters (specimen processing and assay run time, ease of use) and percent agreement between the tests were calculated using JMP Pro11 (SAS Corp, Cary, NC, USA). Results: Mean age was 62 ± 15 years; 108 (54 %) were male. Both tests were successfully performed in all patients. The POC test was rated by endoscopy nurses as easy/very easy to conduct in 193 patients (97 %); median assay run time and median time for specimen collection and processing were 55 minutes (interquartile range IQR: 53 – 55 minutes) and 3 minutes (IQR: 3 – 6 minutes), respectively. In 200/201 (99.5 %) tests, there was agreement between the POC and reference PCR. Conclusions: The more comprehensive POC CRO testing of patients in the endoscopy suite is feasible and results are available in \u3c 1 hour. This strategy may enable rapid risk stratification of duodenoscope exposure to CRO and potentially improve operational efficiency and decrease costs