Nosocomial antimicrobial resistance surveillance

Staphylococcus aureus nasal carriage among the diabetic and non-diabetic haemodialysis patients

Staphylococcus aureus is the most common cause of serious infections in patients undergoing long-term haemodialysis (HD). S. aureus infections in HD patients are associated with considerable morbidity and mortality. Especially, methicillin-resistant S. aureus (MRSA) strains are becoming increasingly multidrug-resistant and have recently developed resistance to vancomycin, used successfully to treat MRSA for more than 30 years. In vitro determination of resistance patterns of S. aureus is critical in terms of administering suitable antimicrobial treatment. The objective of this study was to identify the frequency of S. aureus among diabetic and non-diabetic HD patients and to investigate resistance patterns against various antibiotics used broadly for treatment. This study was carried out between January 2004 and December 2004. In the present survey, 261 patients undergoing HD treatment from three HD units in Hatay were examined. A total of 148 Staphylococcus aureus strains were processed to assess their occurrence rates and antimicrobial susceptibility profiles. S. aureus positivity was determined in 148 (56.7%) of the 261 HD patients and 26 (16.2%) of the 160 individuals in the control group. The difference was significant (p < 0.001). HD length was found to be 38.4 +/- 24.3 months in the patients of S. aureus carrier and 27.3 +/- 18.5 months in non-carrier patients. Significant correlation was also identified between durations those on HD and the isolation of S. aureus (p < 0.001). However, the carrier state was unrelated to the presence of diabetes mellitus (DM), age or sex. In conclusion, nasal carriage of S. aureus was found to be more prevalent in HD patients than that in those in the control group. Also, it is concluded that DM was not a risk factor for the nasal carriage of S. aureus. In addition, the rates of antibiotic resistance of S. aureus strains were found to be quite higher in HD patients than in the control group (p < 0.05).

[Meticillin-resistant Staphylococcus aureus: incidence, risk factors and interest of systematic screening for colonization in intensive-care unit]

OBJECTIVE

To summarize recent international and national epidemiological data of methicillin-resistant Staphylococcus aureus (MRSA) colonization in ICU.

STUDY DESIGN

Review articles using Medline, CDC (Atlanta, GA, USA) and IVS (St Maurice, France) databases (1994-2004): critical assessment of literature and data of MRSA colonization epidemiology in ICU.

RESULTS

MRSA colonization varied from 3 to 14% on ICU admission. Five to twelve percent of patient acquired MRSA colonization during hospitalization. This reservoir is often unknown as clinical sample identifies only a part of MRSA colonization. The probability to develop an infection caused by MRSA in colonized patients is about 30%. Acquisition of MRSA in ICU patients is strongly and independently influenced by colonization pressure.

CONCLUSION

Systematic screening for colonization on ICU admission and during hospitalization is essential for many authors to control the spread of MRSA. Other policies such as implementation of isolation precaution and antibiotic use also contribute to decrease the MRSA incidence rate observed for several years in French ICU.

[Methicillin-resistant Staphylococcus aureus (MRSA) in rehabilitation and chronic-care-facilities: what is the best strategy?]

BACKGROUND

The risk associated with methicillin-resistant Staphylococcus aureus (MRSA) has been decreasing for several years in intensive care departments, but is now increasing in rehabilitation and chronic-care-facilities (R-CCF). The aim of this study was to use published data and our own experience to discuss the roles of screening for MRSA carriers, the type of isolation to be implemented and the efficiency of chemical decontamination.

DISCUSSION

Screening identifies over 90% of patients colonized with MRSA upon admission to R-CCF versus only 50% for intensive care units. Only totally dependent patients acquire MRSA. Thus, strict geographical isolation, as opposed to "social reinsertion", is clearly of no value. However, this should not lead to the abandoning of isolation, which remains essential during the administration of care. The use of chemicals to decolonize the nose and healthy skin appeared to be of some value and the application of this procedure could make technical isolation unnecessary in a non-negligible proportion of cases.

SUMMARY

Given the increase in morbidity associated with MRSA observed in numerous hospitals, the emergence of a community-acquired disease associated with these strains and the evolution of glycopeptide-resistant strains, the voluntary application of a strategy combining screening, technical isolation and chemical decolonization in R-CCF appears to be an urgent matter of priority.

Emergence, spread, and characterization of phage variants of epidemic methicillin-resistant Staphylococcus aureus 16 in England and Wales

Epidemic methicillin-resistant Staphylococcus aureus 16 (EMRSA-16) and EMRSA-15 are the two most important and prevalent EMRSA strains found in the United Kingdom and have also been found in a number of European countries and the United States. We describe for the first time the spread of an EMRSA strain (EMRSA-16) from its point of origin in one hospital to the surrounding hospitals and regions over the following 2 years. In the first 18 months after its original appearance, 136 hospitals referred EMRSA-16 isolates for typing, and interhospital and intraregional spread were reported: it was more prevalent in males between 60 and 80 years old and was isolated from sputum and throat more often than EMRSA-15. Important characteristics, e.g., carriage of the enterotoxin A (sea) and toxic shock syndrome toxin (tst) genes and production of urease, are described. Phage-variant strains of EMRSA-16 which share some of the characteristics of the classical strain, including toxin carriage and urease production, emerged, but without genotypic investigations, their relationship could only be inferred. A total of 129 clinical isolates from 52 hospitals, collected between March 1998 and April 1999 and representing classical EMRSA-16 (49 isolates) or phage variants (80 isolates), were compared by phage typing, pulsed-field gel electrophoresis (PFGE) following SmaI macrorestriction, antimicrobial susceptibility testing, urease production, and PCR detection of toxin gene carriage. PFGE analysis revealed 29 profiles, A1 to A29, with A1 representing the prototypic strain, NCTC 13143. All other profiles differed from A1 by 1 to 6 bands, but some differed from each other by up to 10 bands.

Methicillin-resistant Staphylococcus aureus (MRSA) in rehabilitation and chronic-care-facilities: what is the best strategy?

Background

The risk associated with methicillin-resistant Staphylococcus aureus (MRSA) has been decreasing for several years in intensive care departments, but is now increasing in rehabilitation and chronic-care-facilities (R-CCF). The aim of this study was to use published data and our own experience to discuss the roles of screening for MRSA carriers, the type of isolation to be implemented and the efficiency of chemical decolonization.

Discussion

Screening identifies over 90% of patients colonised with MRSA upon admission to R-CCF versus only 50% for intensive care units. Only totally dependent patients acquire MRSA. Thus, strict geographical isolation, as opposed to "social reinsertion", is clearly of no value. However, this should not lead to the abandoning of isolation, which remains essential during the administration of care. The use of chemicals to decolonize the nose and healthy skin appeared to be of some value and the application of this procedure could make technical isolation unnecessary in a non-negligible proportion of cases.

Summary

Given the increase in morbidity associated with MRSA observed in numerous hospitals, the emergence of a community-acquired disease associated with these strains and the evolution of glycopeptide-resistant strains, the voluntary application of a strategy combining screening, technical isolation and chemical decolonization in R-CCF appears to be an urgent matter of priority.

The impact of methicillin-resistant Staphylococcus aureus in a neurosurgical unit: a growing problem

OBJECT

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a growing problem worldwide. To investigate the severity of the problem, the authors surveyed the incidence of MRSA colonization and infection in the neurosurgical unit at their institution.

METHODS

Patients colonized or infected with MRSA who had been treated in the neurosurgical unit between 1993 and 1999 were retrospectively identified from laboratory records. There were 203 patients with MRSA-positive cultures, and the incidence of infection increased between 1993 (16 cases; 1.9% of admissions) and 1999 (60 cases; 6.7% of admissions). The mean duration of hospital stay was longer in patients with MRSA than in all patients treated in the unit (33.6 compared with 10.3 days, p < 0.001). Methicillin-resistant S. aureus was isolated from the nose in 89 patients, the throat in 79, the perineum in 52, surgical wounds in 16, sputum in 15, blood in 10, and from multiple sites in 69 patients. Fifty-six patients (28%) were infected with MRSA, and there were 15 deaths, of which three (20%) were likely to be due to the infection. The sources of MRSA included the neurosurgical ward in 84 patients, the intensive care unit in 28, other hospitals in 39, and the community in 17. The common strains of MRSA isolated were epidemic (E)MRSA- 16 (110 cases) and EMRSA-15 (31 cases). The microorganism was eradicated in 16 cases, not eradicated in 20, and 167 patients were discharged from the hospital before eradication was achieved. All MRSA isolates were sensitive to vancomycin and teicoplanin and there was reduced sensitivity to mupirocin.

CONCLUSIONS

Infection with MRSA is a growing problem in the neurosurgical population, and most cases are hospital-acquired and are associated with longer hospital stays. Asymptomatic colonization by this organism is far more common than infection of the surgical wound, although there is still morbidity due to MRSA sepsis. Most patients with MRSA are discharged before eradication of infection is achieved, thus increasing the risk that the infection will spread in the community. Strict adherence to the basic principles of infection control is the key to eradication of MRSA.

CP6679, a new injectable cephalosporin with broad spectrum and potent activities against methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa

The antibacterial activities of CP6679, a new injectable cephalosporin with a broad antibacterial spectrum, were compared with those of other cephalosporins. CP6679 had stronger in-vitro activity than ceftazidime and cefpirome against methicillin-resistant Staphylococcus aureus(MRSA), methicillin-resistant coagulase-negative staphylococci, and Pseudomonas aeruginosa. Its activity against MRSA was eight times stronger than that of cefpirome, and it showed high binding affinity for penicillin-binding protein 2' of MRSA. Furthermore, the antibacterial activity of CP6679 against ceftazidime-resistant and imipenem-resistant P. aeruginosawas eight times stronger than that of ceftazidime and four times stronger than that of imipenem. In addition to its in-vitro activities, CP6679 showed the highest efficacy among all cephalosporins tested in murine models of systemic infection induced by MRSA or P. aeruginosa. It was more effective than vancomycin and cefpirome against respiratory tract infections induced by MRSA in mice.

Methicillin-resistant Staphylococcus aureus in geriatric patients: usefulness of screening in a chronic-care setting

OBJECTIVE

To evaluate the contribution of screening to the detection of cases of methicillin-resistant Staphylococcus aureus (MRSA) in a chronic-care facility.

DESIGN

Surveillance and laboratory observational study.

METHODS

During a 7-month period, we compared imported and acquired MRSA in a chronic-care center by screening patients for carriage of MRSA on admission and discharge, and by recording all cases of clinical specimens positive for MRSA.

SETTING

The study was conducted in a 120-bed chronic-care center. This center admits approximately 850 patients per year. Approximately 90% of the patients were elderly and were admitted from other hospitals.

RESULTS

Of 519 patients admitted during the study period, 129 were positive for MRSA at some point during their residence, including 60 (11.6%) with MRSA found within 48 hours of admission and 69 (13.3%; 53% of all positives) with nosocomial MRSA Of the 519 admissions, 332 (64%) were discharged, of whom 62 (19%) were positive for MRSA Of these 62, 43 (69%) acquired their MRSA during their stay in the center.

CONCLUSIONS

Our study confirms the amplification effect of chronic-care facilities on MRSA propagation. It also shows that screening for MRSA carriage in a chronic-care center facilitates the early identification of a large proportion of patients with MRSA.

Methicillin-resistant Staphylococcus aureus in the community: new battlefronts, or are the battles lost?

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial infections worldwide. Interpretation of community MRSA trends is problematical, in that the term is ill-defined, and related data are difficult to put into context. There are four relevant battlefronts, all of interest to risk assessment and prevention. These comprise the following: the issues relating to an increasing pool of patients with MRSA discharged from hospitals into the community; MRSA spreading to patients in nursing and residential homes; and MRSA spreading from patients and healthcare workers to others in the community. There are often difficulties in determining whether the fourth issue, MRSA arising apparently de novo in the community, is in fact due to one of these other fronts. All these battlefronts are important and not yet lost. However, we must agree on definitions and design-appropriate surveillance strategies, so that we can best inform prevention and control activities to contain these emerged or emerging problems.