The screening of methicillin-resistant staphylococcus aureus in vascular surgery patients: a comparison of molecular testing and broth-enriched culture

Epidemiology and clinical relevance of Staphylococcus aureus intestinal carriage: a systematic review and meta-analysis

INTRODUCTION

Recent data highlight the importance of screening more than one site for improving the detection of S. aureus colonization. Intestinal carriage is frequently under-investigated and its clinical impact ought to be defined a better way. Areas covered: This review and meta-analysis provide an updated overview of prevalence, characteristics and clinical significance of S. aureus intestinal carriage in different populations, both for methicillin-susceptible and -resistant S. aureus strains. Expert commentary: Intestinal S. aureus carriage is documented with higher prevalence in children and in patients with S. aureus skin and soft tissue infections. This site of colonization was shown to be associated with a high risk of dissemination in the environment and with S. aureus infection. Intestinal carriage is frequently retrieved in nasal carriers, reflecting probably an association with a high bacterial load. Exclusive intestinal carriage present in one third of intestinal carriers can be associated with infection. Comparative genotyping analysis of different strains from nasal and extra-nasal sites of carriage, including the intestinal ones, in the same individuals, would allow a better comprehension of the pathophysiology of S. aureus endogenous infection. It could also permit to improve the prevention of these infections by decolonization of sites implicated in infection genesis.

Carriage of multidrug-resistant organisms in a tertiary university hospital in Albania-a point prevalence survey

BACKGROUND

Antimicrobial resistance has been recognised as a serious global Public Health problem. Prevalence of Multiple-Drug-Resistant (MDR) organism carriage in Albania is largely unknown since no national surveillance system is in place and few publications are accessible in the literature.

METHODS

A 1-day point-prevalence-survey (PPS) screening for nasal methicillin-resistant Staphylococcus aureus (MRSA) and rectal MDR Gram-negative carriage was carried out at the high-dependency wards in the country's only tertiary care hospital, in Tirana.

RESULTS

A total of 106 nasal and 104 rectal swabs were collected. 14.2 % of patients (95 % Confidence Interval [95 CI]: 8.1-22.3 %) were MRSA nasal carriers. Resistance to aminoglycosides and fluoroquinolones was common in these isolates (≥80 %) but no resistance was identified against glycopeptides, nitrofurantoin and the relatively newer agents, tigecycline and linezolid. Fifty Enterobacteriaceae isolates were cultivated from 33 of 104 screened patients (31.7 % [95 CI: 22.9-41.6 % 95 CI]). The prevalence of Extended Spectrum Beta-Lactamase (ESBL) production in Enterobacteriaceae was 41.3 % (95 CI: 31.8-51.4 %). The two more commonly isolated Enterobacteriaceae were E. coli ([n = 28], 24 ESBL positive; 1 AmpC positive and 3 without an identified mechanism of resistance) and Klebsiella pneumoniae ([n = 13], all ESBL positive; 1 also AmpC and metallo-β-lactamase (MBL) positive). Susceptibility to carbapenems (≥98 %), fosfomycin (90 %) and amikacin (70 + 20 % intermediate) was high but a high level of resistance to all other agents tested was noted. Non-fermenting Gram-negative bacilli were less commonly isolated {22 isolates: Acinetobacter baumannii (9); Pseudomonas aeruginosa (8) and Stenotrophomonas maltophilia (5)}.

CONCLUSION

Although a significant rate of MRSA carriage was identified, the main resistance challenge in Albania appears to be linked with Gram-negative organisms, particularly ESBL in Enterobacteriaceae.

Carriage and Genetic Diversity of Methicillin-Resistant Staphylococcus aureus among Patients and Healthcare Workers in a Serbian University Hospital

OBJECTIVES

There is a paucity of data on methicillin-resistant Staphylococcus aureus (MRSA) epidemiology among Balkan countries. The aim of our study was to determine the prevalence of nasal and pharyngeal carriages and diversity of MRSA among patients and healthcare workers (HCWs) in the major referral centre in Serbia, and to evaluate performance of three different media for MRSA screening.

METHODS

Nasal and pharyngeal swabs were obtained from 195 patients and 105 HCWs in Emergency Department (ED), Surgical Department (SD) and Medical Department (MD). After broth enrichment, samples were inoculated onto MRSA-ID, ORSA and oxacillin-MSA and incubated for 24/48 hours. Characterisation of isolated MRSA strains was determined by MLVA, spa, SCCmec and agr typing, PVL genes detection and antimicrobial susceptibility.

RESULTS

MRSA carriage prevalence was 11.8% in patients and 7.6% in HCWs. Introduction of pharyngeal swabs in screening procedure increased MRSA carriage rate by over 30%. Variable found to be independently associated with an increased risk for MRSA carriage was ED (odd ratio (OR) = 4.45, 95% confidence interval (CI) 1.78-11.14). A higher risk of multidrug-resistant MRSA carriage was observed among patients (OR = 22; 95% CI 1.92-251.54). CC5-MRSA-SCCmecI was the dominant clone among patients and HCWs in ED and MD, while high genetic diversity of community-associated MRSA (CA-MRSA) was shown in SD especially among HCWs. MRSA-ID was superior to the other tested media with a sensitivity/specificity of 95.2% and 99.6% after 48 hours of incubation.

CONCLUSIONS

These results indicate high MRSA carriage rate in the hospital and emergence of CA-MRSA through HCWs in these settings. MRSA-ID was the optimal available choice for MRSA screening.

Potentiation of the in vitro antistaphylococcal effect of oxacillin and tetracycline by the anti-inflammatory drug diacetyl rhein

BACKGROUND

The anti-inflammatory drug diacetyl rhein has been found to possess promising antistaphylococcal effects against various drug-resistant strains in our previous study. In the present work, we explored the in vitro combinatory interactions of diacetyl rhein with oxacillin and tetracycline against 13 standard strains and clinical isolates of Staphylococcus aureus, including those resistant to erythromycin, methicillin and tetracycline.

METHODS

Minimum inhibitory concentrations were determined by broth microdilution assay, and the effects of combinations were evaluated according to the sum of fractional inhibitory concentrations (ΣFICs).

RESULTS

Synergistic or additive effects were observed against all S. aureus strains (ΣFIC 0.258-1), whereas diacetyl rhein-oxacillin appeared to be the most effective combination, synergistically inhibiting the growth of 4 strains tested.

CONCLUSION

To our best knowledge, this is the first report on a synergistic antibacterial effect of diacetyl rhein. Our results suggest this promising compound for further evaluation of its synergistic anti-infective potential as an agent with a combined anti-inflammatory and synergistic antibacterial action.

Using daptomycin in hospitalised patients with cSSTI caused by Staphylococcus aureus has an impact on costs

BACKGROUND

The aim was to assess the cost impact of daptomycin compared to vancomycin treatment in patients hospitalised for complicated skin and soft-tissue infection (cSSTI) with suspected methicillin-resistant Staphylococcus aureus infection in the UK.

METHODS

A decision model was developed to estimate the costs associated with cSSTI treatment. Data on efficacy, treatment duration and early discharge from published clinical trials were used, with data gaps on standard clinical practice being filled by means of clinician interviews.

RESULTS

Total health-care costs per patient were GBP 6,214 and GBP 6,491 for daptomycin and vancomycin, respectively. A sensitivity analysis suggested that modifying the parameters within a reasonable range does not impact on the conclusion that the higher cost of daptomycin is likely to be offset by lower costs of monitoring and hospitalisation.

CONCLUSIONS

This study demonstrates that daptomycin not only provides an alternative treatment for multiple resistant infections, but may also reduce National Health Service costs.

Oxacillin resistance and antimicrobial susceptibility profile of Staphylococcus saprophyticus and other staphylococci isolated from patients with urinary tract infection

BACKGROUND

Staphylococcus saprophyticus is the second most frequent community-acquired causative agent of urinary tract infection (UTI). The objective of this study was to evaluate the susceptibility profile and resistance detection in Staphylococcus species. isolated from patients with UTI.

MATERIALS AND METHODS

The isolates were investigated using the disk diffusion method, Vitek I system, E-test®, and detection of the mecA gene.

RESULTS

Most isolates (76.2%) were resistant to oxacillin by the disk diffusion method, followed by those resistant to penicillin (72.2%). The oxacillin disk diffusion method, E-test, and Vitek I method showed higher sensitivity (94.4%) and lower specificity (28.9, 26.5, and 24.0%, respectively) than the cefoxitin disk diffusion test (sensitivity: 83.5%, specificity: 85.5%) for the detection of oxacillin resistance.

CONCLUSIONS

The large number of oxacillin-resistant isolates indicates that the breakpoint value recommended by the Clinical and Laboratory Standards Institute may overestimate oxacillin resistance in S. saprophyticus. Thus, changes in these guidelines are necessary for the correct detection of this resistance.