Nosocomial Methicillin-resistant Staphylococcus Aureus Infections Research Articles

Increasing nosocomial infections of methicillin-resistant Staphylococcus aureus at a teaching hospital in Taiwan

Methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide important pathogen in nosocomial infections. To investigate the extent of the problem in Taiwan, analysis for the period of 1981–1994 was carried out of prospective surveillance data from the National Taiwan University Hospital, a major university teaching hospital in Taiwan. The number of nosocomial MRSA infections increased from five in 1981 to 133 in 1994, and the incidence increased from 0.2 episodes/1000 discharges in 1981 to 2.9 episodes/1000 discharges in 1994. The most common infection site was surgical wounds, which accounted for 26.3% of total 577 episodes of nosocomial MRSA infections during the study period. However, bacteraemia has become more and more common during the past 14 years. MRSA infections occured more frequently in patients stayed in the burn unit and other intensive care units than in the general wards. Other than oxacillin, the resistance rate to many other antibiotics also increased in S. aureus strains causing nosocomial infections in this hospital. Vancomycin remained active to all these S. aureus strains, even until 1994.

Prevention and Control of Methicillin-Resistant Staphylococcus aureus Nosocomial Infection in Barcelona (Spain)

Methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections with multiply-resistant epidemic strains are an important infection control problem in hospitals in Barcelona, Spain. A prospective survey, using a questionnaire mailed or faxed to all public network hospitals (n = 40) in Barcelona and the surrounding area, was used to evaluate the prevalence of MRSA nosocomial infections and the use of control measures. The questionnaire inquired about demographic, microbiological and epidemiological data regarding MRSA nosocomial infections and what measures were used to control them. All 9 large hospitals ( > 500 beds) and 15/31 smaller hospitals (

Control of Methicillin-Resistant Staphylococcus aureus at a University Hospital: One Decade Later

To investigate the cause of increasing rates of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection at a university hospital. Review of data collected by prospective hospital wide surveillance regarding rates of nosocomial MRSA colonization and infection. A 700-bed university hospital providing primary and tertiary care. Patients admitted to the hospital between 1986 and 1993 who were found to be infected or colonized with MRSA. Rates of MRSA infection and colonization. MRSA infection or colonization was identified in 399 patients (0.18%) admitted during the 8-year study. There was no correlation between the annual rates of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infections (P = .66). The frequency of both nosocomial and non-nosocomial cases increased significantly over the last 4 years of the study (P < .001 for trend). The ratio of patients who had acquired MRSA nosocomially to those admitted who already were infected or colonized decreased significantly during the study period (P = .002 for trend). There was a significant increase in the frequency of patients with MRSA being transferred from nursing homes and other chronic care facilities (P = .011). A cost-benefit analysis suggested that surveillance cultures of patients transferred from other healthcare facilities would save between $20,062 and $462,067 and prevent from 8 to 41 nosocomial infections. An increase in the incidence of nosocomial MRSA infection was associated with an increased frequency of transfer of colonized patients from nursing homes and other hospitals. The lack of correlation between rates of MRSA and MSSA infections suggested that MRSA infections significantly increased the overall rate of staphylococcal infection. Screening cultures of transfer patients from facilities with a high prevalence of MRSA may offer significant benefit by preventing nosocomial infections and reducing patient days spent in isolation.

Control of Methicillin-Resistant Staphylococcus aureus in a Hospital and an Intensive Care Unit

To describe methicillin-resistant Staphylococcus aureus (MRSA) control in a hospital, including a surgical intensive care unit (SICU) outbreak.Prospective surveillance of newly identified patients with MRSA. Barrier isolation (disposable gloves for direct contact with patient or immediate environment) was used for the routine care of hospitalized MRSA patients as of October 1991. Beginning in 1992, MRSA isolates were typed by restriction endonuclease enzyme analysis of plasmid DNA (REAP) and/or pulsed-field gel electrophoresis of genomic DNA (PFGE). Surveillance information and MRSA typing were used concurrently to identify nosocomial case clustering, confirm cross-infection, and support a need for additional outbreak control interventions.University-affiliated public hospital.Patients with newly identified MRSA colonization or infection from 1991 through 1993 and epidemiologically associated staff providing care to eight SICU patients in an outbreak.Barrier isolation for affected and unaffected patients in and admitted to the SICU institution when the outbreak was identified and cross-infection confirmed. Anterior nares cultures of staff in contact with outbreak cases for detection of MRSA colonization.Fifty-six hospitalized patients with community-acquired MRSA and 80 patients with nosocomial MRSA colonization or infection were identified during the 3 years. After the introduction of barrier isolation, the annual frequency of new nosocomial MRSA cases decreased and only one outbreak (eight cases in the SICU) caused by type-related isolates occurred. The other 35 nosocomial cases of MRSA during 1992 and 1993 were not epidemiologically related or were caused by isolates with different types. The SICU outbreak ended after instituting barrier isolation for all patients (with and without MRSA) in and admitted to the unit. Six colonized SICU staff were identified. All outbreak cases had identical or related MRSA types by PFGE and REAP. Staff isolates were different from case isolates by typing, and staff were not restricted and not given treatment for colonization. After more than 6 months of follow up, no further outbreaks of MRSA in the SICU or elsewhere in the hospital occurred despite returning to barrier isolation for affected patients only.MRSA in hospitals and outbreaks of MRSA in ICUs can be controlled by surveillance and minimal barrier interventions. REAP or PFGE typing of MRSA can be used to support or refute the presence of cross-transmission. Typing also may be helpful when planning and assessing the effectiveness of interventions directed at endemic, as well as outbreak, MRSA control.

Control of Methicillin-Resistant Staphylococcus aureus in a Hospital and an Intensive Care Unit

To describe methicillin-resistant Staphylococcus aureus (MRSA) control in a hospital, including a surgical intensive care unit (SICU) outbreak. Prospective surveillance of newly identified patients with MRSA. Barrier isolation (disposable gloves for direct contact with patient or immediate environment) was used for the routine care of hospitalized MRSA patients as of October 1991. Beginning in 1992, MRSA isolates were typed by restriction endonuclease enzyme analysis of plasmid DNA (REAP) and/or pulsed-field gel electrophoresis of genomic DNA (PFGE). Surveillance information and MRSA typing were used concurrently to identify nosocomial case clustering, confirm cross-infection, and support a need for additional outbreak control interventions. University-affiliated public hospital. Patients with newly identified MRSA colonization or infection from 1991 through 1993 and epidemiologically associated staff providing care to eight SICU patients in an outbreak. Barrier isolation for affected and unaffected patients in and admitted to the SICU institution when the outbreak was identified and cross-infection confirmed. Anterior nares cultures of staff in contact with outbreak cases for detection of MRSA colonization. Fifty-six hospitalized patients with community-acquired MRSA and 80 patients with nosocomial MRSA colonization or infection were identified during the 3 years. After the introduction of barrier isolation, the annual frequency of new nosocomial MRSA cases decreased and only one outbreak (eight cases in the SICU) caused by type-related isolates occurred. The other 35 nosocomial cases of MRSA during 1992 and 1993 were not epidemiologically related or were caused by isolates with different types. The SICU outbreak ended after instituting barrier isolation for all patients (with and without MRSA) in and admitted to the unit. Six colonized SICU staff were identified. All outbreak cases had identical or related MRSA types by PFGE and REAP. Staff isolates were different from case isolates by typing, and staff were not restricted and not given treatment for colonization. After more than 6 months of follow up, no further outbreaks of MRSA in the SICU or elsewhere in the hospital occurred despite returning to barrier isolation for affected patients only. MRSA in hospitals and outbreaks of MRSA in ICUs can be controlled by surveillance and minimal barrier interventions. REAP or PFGE typing of MRSA can be used to support or refute the presence of cross-transmission. Typing also may be helpful when planning and assessing the effectiveness of interventions directed at endemic, as well as outbreak, MRSA control.

当院におけるＭＲＳＡ感染症

To analyze the frequency of methicillin resistant staphylococcus aureus (MRSA) infection, we investigated the cases who were infected with MRSA in our hospital. From 1989 to 1993, 9906 cases of hospitalized patients were available for investigation. Of these 8372 cases required surgical treatment. There were 31 cases whose wounds were infected. Of these 10 cases were identified as having MRSA infection. Wound infection with MRSA increased in association with the increase in usage of third generation cephem antibiotics after surgical treatment. Another 10 cases, aged from 62 to 92 years (average 78.4 years), contracted MRSA infections, although they had not had not any surgical treatment although all of these patients were compromised hosts. The mortality rate of MRSA pneumonia was 33.3%. For prevention of nosocomial MRSA infection, systemic organization of an MRSA infection team is very important.

Potent in vitro bactericidal activity of polymyxin B against methicillin-resistant Staphylococcus aureus (MRSA).

Eradication of methicillin-resistant Staphylococcus aureus (MRSA) carried by inpatients or healthy hospital personnel by topical use of antibiotics is an important step for preventing outbreak of MRSA nosocomial infection. In the screening of the antibiotic best suited for this purpose, we have found that polymyxin B, a commonly used antibiotic for gram-negative infection, had an unexpected strong cytokilling activity towards MRSA clinical strains, which was more potent than that of vancomycin or gentamicin. The data suggested that polymyxin B could be an antibiotic of choice in the treatment of topical carriage of or infection caused by MRSA.

Genomic DNA fingerprinting by pulsed-field gel electrophoresis as an epidemiological marker for study of nosocomial infections caused by methicillin-resistant Staphylococcus aureus

In this study, we have compared genomic DNA fingerprintings among isolates of methicillin-resistant Staphylococcus aureus (MRSA) by using pulsed-field gel electrophoresis (PFGE). Chromosomal fragments digested with SmaI were most suitable for the PFGE separation. SmaI cut genomic DNA into 15 to 20 fragments whose sizes ranged from about 30 to 1,500 kb. Thirty-one distinctive fragment patterns were identified in 111 infecting and colonizing MRSA isolates from six different hospitals in Japan. On the basis of the genomic typing by PFGE, we performed an epidemiological investigation of an outbreak of nosocomial MRSA infections among inpatients in Nagoya University Hospital. Ten types of chromosomal digestion were identified in the 20 strains isolated from 18 infected patients and 1 from colonized hospital personnel. According to the restriction patterns, we found that four types of these strains had caused epidemic infections among 13 patients in the outbreak. Two types (types 1 and 4) of the strains were involved in the death of five patients. The other infections were sporadic. The clarity and polymorphism of the chromosomal digestion patterns enabled us to discriminate between isolates which could not be differentiated by antibiogram or plasmid analysis. Classification of the genomic DNA fingerprinting patterns by PFGE is therefore proposed as a useful method for investigating the source, transmission, and spread of nosocomial MRSA infections.

The clinical microbiology laboratory as an aid in infection control the application of molecular techniques in epidemiologic studies of methicillin-resistant Staphylococcus aureus

A microbiologic surveillance study was performed in order to estimate the point prevalence, source, and nosocomial acquisition of methicillin-resistant Staphylococcus aureus (MRSA) within the Iowa City Veterans Affairs Medical Center (IC VAMC). Immediately following the microbiologic surveillance study, a cluster of nosocomial MRSA infections was detected by routine infection control surveillance. An epidemiologic investigation was conducted and all isolates of MRSA detected during the microbiologic surveillance study and the subsequent cluster of nosocomial infections were characterized by restriction endonuclease analysis of plasmid DNA (REAP). REAP subtyping defined a total of ten distinct subtypes from 24 patients infected or colonized with MRSA. The documentation of a single subtype of MRSA (subtype A2) in nine patients from the surgical service, eight of which were hospitalized in the surgical intensive care unit, provided convincing evidence of a breakdown of infection control practices in that unit. REAP subtyping was a highly discriminating means of identifying different subtypes among the various isolates of MRSA and was useful in directing infection control efforts to specific problem areas within the hospital. Molecular typing methods, such as REAP, when used appropriately in conjunction with careful epidemiologic investigation provide an effective approach to the investigation and control of the spread of MRSA within the hospital.

Effectiveness of Simple Measures to Control an Outbreak of Nosocomial Methicillin-Resistant Staphylococcus aureus Infections in an Intensive Care Unit

Between June 1985 and March 1986, 14 cases of severe nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection, including septicemia, were observed in the intensive care unit (ICU) of a 400-bed cancer reference center. Simple control measures including contact isolation of colonized patients and reinforcement of handwashing practices among personnel were followed by a sharp decrease in the rate of infection and colonization. An epidemiological investigation showed that a single serophage variant MRSA strain was involved; peak incidence of infection was 17 per 100 ICU patient discharges; the index case was identified as a patient admitted from another hospital and the epidemic strain was then transmitted from patient-to-patient in the ICU; risk factors for acquiring infection were length of prior hospitalization, invasive procedures and number of antibiotic treatments; dissemination of the strain to other wards was only anecdotal. These results stress the effectiveness of simple measures to control outbreaks of MRSA nosocomial infections even in immunocompromised cancer patients.

Effectiveness of Simple Measures to Control an Outbreak of Nosocomial Methicillin-Resistant Staphylococcus aureus Infections in an Intensive Care Unit

AbstractBetween June 1985 and March 1986, 14 cases of severe nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection, including septicemia, were observed in the intensive care unit (ICU) of a 400-bed cancer reference center. Simple control measures including contact isolation of colonized patients and reinforcement of handwashing practices among personnel were followed by a sharp decrease in the rate of infection and colonization. An epidemiological investigation showed that a single serophage variant MRSA strain was involved; peak incidence of infection was 17 per 100 ICU patient discharges; the index case was identified as a patient admitted from another hospital and the epidemic strain was then transmitted from patient-to-patient in the ICU; risk factors for acquiring infection were length of prior hospitalization, invasive procedures and number of antibiotic treatments; dissemination of the strain to other wards was only anecdotal. These results stress the effectiveness of simple measures to control outbreaks of MRSA nosocomial infections even in immunocompromised cancer patients.

Prevalence and significance of methicillin-resistant Staphylococcus aureus in patients with cystic fibrosis.

Recent reports indicate that methicillin-resistant Staphylococcus aureus (MRSA) may be emerging as a significant pediatric nosocomial pathogen. Children with cystic fibrosis (CF) pulmonary disease are subject to many of the risk factors for MRSA colonization and/or infection. We retrospectively investigated the prevalence and significance of MRSA from sputum and throat cultures in 452 patients with CF followed during 1986. No MRSA had been isolated during 1984 or 1985. Although S. aureus was isolated from 212 patients (47%) in 1986, only 14 (3%) showed MRSA. The MRSA strains had 11 different antimicrobial susceptibility patterns. Neither age, clinical condition, nor recent prior hospitalization correlated with MRSA acquisition. Acquisition did not appear to directly affect the course of the pulmonary disease in these patients even though no patient received any treatment for their MRSA. The prevalence of MRSA is low, although patients with CF are subject to many risk factors. MRSA appears to be mainly community-acquired and to represent colonization rather than infection. However, the potential for nosocomial MRSA infection is present, and vigilance is required in monitoring any changes in frequency of isolation or infection with these organisms.