Muco-cutaneous colonization and nosocomial infections caused by methicillin-resistant Staphylococcus aureus and Acinetobacter baumanii in intensive care patients

This study was designed to assess the frequency and risk factors for colonization with MRSA and A. baumanii in the intensive care unit, and to analyse the relationship between colonization and infection with MRSA or A. baumanii. During a 24-day survey period, colonization was studied weekly with nasal, throat and digit skin swabs; nosocomial infections were routinely monitored according to CDC recommendations. Clinical data and invasive procedures were registered during a one-year non-epidemic period; 103 ICU patients hospitalized for more than 7 days were prospectively included. We investigated acquired colonization and nosocomial infection with SAMR or A. baumanii for 87 patients not colonized by SAMR or A. baumanii on admission. The colonization acquisition rate was 56% for MRSA and 27% for A. baumanii. Infection incidence (cases per 1,000 patient-days) was 6.46 for MRSA and 1.61 for A. baumanii. On univariate analysis, acquired MRSA colonization was associated with longer ICU stays, longer mechanical ventilation and longer central venous catheterization. Multivariate analysis only showed an association with longer ICU stay. Acquired A. baumanii colonization was associated with SAPSII, longer mechanical ventilation, and longer central venous catheterization in univariate analysis. Multivariate analysis only showed an association with SAPSII and longer mechanical ventilation. In this study, SAMR or A. baumanii infections were not associated with colonization or clinical setting or invasive procedures.     

Methicillin-resistant Staphylococcus aureus (MRSA) in an intensive care unit: a one-year survey

Methicillin-resistant Staphylococcus aureus (MRSA) is frequently isolated in nosocomial outbreaks. In our study, we analysed the occurrence of colonisation and infection in an Intensive Care Unit of our hospital during a 12-month period. We also evaluated the possibility of using automated ribotyping as a molecular method in order to type the isolates. Twice a week a nasal swab and a rectal swab were performed on all patients; from ventilator-assisted patients, a sputum culture was also taken. All the MRSA isolated were identified by using commonly phenotypic procedures and on all isolates susceptibility tests were performed. An automated ribotyping using EcoRI was also done. Out of 292 patients enrolled in the study, 205 were never colonised (group N); among the other 87 who were colonised by MRSA (29.8%), 40 patients (group A) were MRSA carriers at the time of admission, while 47 (group B) were colonised in the ICU. Twenty-seven patients (11 from group A, 15 from group B and 1 from group N) developed 31 infections due to MRSA. Patients from group A exhibited, as a rule, worse clinical conditions than those from the other two groups. For the former group, MRSA infection was frequently systemic (sepsis), while in group B pneumonia was the predominant infection. The prevalence of colonisations in our study was 30%, which is a value comparable to those presented by other authors in similar cases. MRSA colonisation is a necessary condition for subsequent infections in almost all cases, with an average lag of 7 days. Susceptibility tests were non-discriminating among the isolates: all the strains were susceptible to glycopeptides; nearly all of them were resistant to erythromycin, clindamycin, ciprofloxacin and gentamicin. Automated ribotyping allowed us to distinguish 12 different ribogroups, the most frequent of which was composed of 146 isolates. In our study, this molecular method was able to define a possible endemic clone that should be better investigated by using methods with a higher discriminatory power, such as RAPD or PFGE. The method that we employed is highly reliable, easy to perform and not time-consuming. In our opinion, it could be the method of choice in the first screening of high numbers of isolates.     

Outbreak of methicillin-resistant Staphylococcus aureus in general hospital intensive care unit]

Mantes' hospital polyvalent intensive care unit (ICU) experienced an outbreak episode caused by methicillin resistant Staphylococcus aureus (MRSA). Suspicion of physicians was strengthened by observing the weekly reading of multiresistant germs and the significative increase of MRSA carriers incidence rate, compared with the number of admission in the ICU: 5.5% to 11.3%. This outbreak was surprising: it happened immediately after the installation in a new hospital and the reinforcement of nosocomial infection surveillance (systematic screening of every patient admitted to the I.U.C., his isolation if he presents risk factors to multiresistant germs, increasing of handwashing stations). The overlapping period of hospitalisation concerning the 13 patients being reported as SARM carrier, having the same antibiogram, and the epidemic curve suggested a cross contamination. The index case was a MRSA carrier the day of her admission and have had a recent hospitalisation in a high risk unit. MRSA has always been isolated in nasal swab. Six patients among the thirteen carriers developed an infection and have been treated by vancomycin: two systemic infections and four pulmonary infections. The mortality rate was 33% and only one of them seemed to be directly due to MRSA. Area samples were all negative. The clinical staff have been screened with nasal swab. We identified only one nasal MRSA carrier. The pulsed-field gel electrophoresis study showed that 9/11 which have been analysed were identical. This outbreak brought about staff, more sensibilisation to the nosocomial infection and updating of plain hygien rules leaded to its stop five months later.     

A sociologic study of health care accessibility in an urban milieu in Tunis

In developing countries, the study of access to medical care reveals the inequality of health coverage. In rural areas, the two main limiting factors are the lack of health services and the difficulty of access, especially distance. But the relevant factors in urban areas have been little studied. In Mellassine, which is the largest slum of Tunis, we studied the behaviour of 400 under-4 children's mothers in relation to health care. The following factors proved relevant: sex of the child, size of the family, father's profession, level of education, material resources; distance, cost and quality of reception of health services; finally the cultural pattern, particularly the representation of children disease by the mothers. Such an approach allows a reflection to reduce the inequality of access to medical care.     

Urinary catheter related nosocomial infections in paediatric intensive care unit

The present prospective study was carried out in the Paediatric Intensive Care Unit (PICU) of a tertiary care teaching hospital in Mumbai. The objective was to determine the incidence, risk factors, mortality and organisms responsible for urinary catheter related infections (UCRI). Colonization and/or bacteriuria was labelled as urinary catheter related infection (UCRI). Forty-four patients with 51 urinary catheters were studied. Incidence of UCRI was 47.06%. Age, female sex and immunocompromised status did not increase the risk of UCRI. Duration of catheter in-situ and duration of stay in the PICU were associated with higher risk of UCRI. The mortality was not increased by UCRI. Commonest organism isolated in UCRI was E. coli, which had maximum susceptibility to nitrofurantoin and amikacin.     

Vancomycin susceptibility of oxacillin-resistant Staphylococcus aureus isolates causing nosocomial bloodstream infections

Nosocomial oxacillin-resistant Staphylococcus aureus (ORSA) bloodstream isolates were tested to determine the prevalence of vancomycin heteroresistance. We screened 619 ORSA nosocomial bloodstream isolates from 36 hospitals between 1997 and 2000. Only one isolate exhibiting heterotypic resistance was detected. Thus, vancomycin heteroresistance in clinical bloodstream isolates remains rare in the United States.     

Staphylococcus aureus nasal carriage as a marker for subsequent staphylococcal infections in intensive care unit patients

From January to December 1994, 752 consecutive patients admitted to intensive care units (ICU) for more than two days were studied prospectively forStaphylococcus aureus colonization and infection. Nasal swabs were obtained at admission and weekly during the ICU stay. At ICU admission 166 patients (22.1%) wereStaphylococcus aureus nasal carriers, while 586 were free of nasal colonization. Of the 166 nasal carriers, 163 harbored methicillin-sensitiveStaphylococcus aureus (MSSA) and three methicillinresistantStaphylococcus aureus (MRSA). During the ICU stay 24 of the 586 noncolonized patients became nasal carriers (11 MSSA and 13 MRSA), and one nasal carrier initially colonized by MSSA was recolonized by MRSA. Staphylococcal infections were documented in 51 (6.8%) of the total 752 patients. After 14 days of ICU stay, the probability of developing staphylococcal infections was significantly higher for those patients who were nasal carriers at ICU admission than for those found to be initially negative (relative risk 59.6, 95% Cl 20.37–184.32; p<0.0001). In patients with ICU-acquired nasal colonization, most infections were documented prior to or at the time of the detection of the nasal colonization; thus, in this group of patients nasal carriage showed a lower predictive value for subsequentStaphylococcus aureus infections than that described classically. Paired isolates of nasal colonizing and clinical strains were studied by pulsed-field gel electrophoresis (PFGE) andmecA polymorphism analysis in 30 patients; identity was demonstrated in all but two patients. The results suggest that, outside the setting of an outbreak of MRSA, the detection ofStaphylococcus aureus nasal carriers on admission may be particularly useful in identifying those patients who are at high risk for developing staphylococcal infections during their ICU stay.     

Inquiry into the incidence of nosocomial infections and evaluation of the transmission of methicillin-resistant Staphylococcus aureus in an orthopedic surgical unit]

Nosocomial infections are an important cause of morbidity and mortality. Methicillin resistant Staphylococcus aureus (MRSA) is often the severe causal agent in this kind of infections. In order to evaluate risk factors for nosocomial infections and nasal MRSA carriage, an incidence study was carried out on patients hospitalized in an orthopaedic surgery department in Boucicaut Hospital (Paris). This study was carried out over a five month period. Data of all the patients who stayed more than two days in the unit were collected in medical and nursing records. Nasal swab specimens were taken at the admission of each patient included in order to screen nasal MRSA carriers. Statistical analysis were performed using Epi Info software version 6.0. A total of 451 patients were included in the study. Nosocomial infections incidence rate was 11.5%. Risk factor significantly associated with nosocomial infection was high wound containation classes III and IV (Altemeier). Incidence rate of MRSA carriage was 3.1%. A previous hospitalization in a general hospital 6 months before an admission at Boucicaut Hospital was the only risk factor identified. According to this, these patients, when they are admitted, are proposed to be preventely isolated awaiting their microbiological results.     

Epidemic of Staphylococcus aureus nosocomial infections resistant to methicillin in a maternity ward

Methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections frequently occur in the hospital environment, but their incidence is less often observed in neonates. In the present investigation, seventeen cases were recorded over a nine-week period (two cases per week). Pulsed field gradient gel electrophoresis confirmed the clonal character of the strain. The hypothesis of manually-transmitted infection due to contamination from multiple sources was reinforced by the fact the epidemic persisted in spite of the elimination of the main human infectious source and an absence of risk factors determined by the case-control study. The role of environmental factors in the persistence of this outbreak of MRSA infection has been considered.     

Impact of an ambulatory care clerkship on the attitudes of students from five classes (1985-1989) toward primary care

This study was designed to evaluate the effects of a required ambulatory care clerkship during the fourth year of medical school on the students' knowledge of primary care medicine and their subsequent career choices. A questionnaire was mailed to the graduates of the Albert Einstein College of Medicine classes of 1985-1989. Fifty-six percent (408) of the questionnaires were returned. An average of 74% of the respondents answered yes to six items that asked whether the clerkship had successfully introduced them to basic concepts and practices of outpatient medicine (range from 58% to 93%, depending on the item). In addition, 90% reported that the clerkship had enhanced their understanding of primary care medicine, while 41% indicated that the rotation had wholly or partially influenced their career choices. The survey findings suggest that exposure to outpatient medicine during medical school plays an important role in facilitating students' knowledge of primary care medicine and influencing their career choices.     

Methicillin-resistant Staphylococcus aureus nosocomial infections in ICU: risk factors, morbidity and cost

OBJECTIVE: Methicillin resistance and infections caused by methicillin-resistant Staphylococcus aureus represent a growing problem and a challenge for health-care institutions. We evaluated risk factors, morbidity and cost of infections caused by methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus. DESIGN: We performed an un-matched case-control study in an 20-bed medical intensive care unit from 1994-2001 at Nantes teaching hospital, France. All patients with pneumonia, bacteraemia and urinary MRSA (cases) or MSSA (controls) nosocomial infections were included in the study. RESULTS: Twenty four patients with MRSA infection were compared to 64 patients with MSSA infections. Patients with MRSA infection were older (56 vs. 45 years, P < 0.01), had longer length of stay (47 vs. 35 days, P < 0.05) and were infected later (22 vs. 10 days, P < 0.00001) than patients with MSSA infection. No difference was observed between the two groups according to the Omega index, acute simplify index and mortality. MRSA infections involved extra cost due to antimicrobial treatment (184 vs. 72 Euros, P < 0.005) and length of stay (37,278 vs. 27,755 Euros, P < 0.05). CONCLUSION: Patient infected by MRSA seems to be different from patient infected by MSSA but without consequence on Omega index and mortality. But methicillin-resistance involves extra cost due to antimicrobial treatment and length of stay.     

Antimicrobial resistance in Staphylococcus aureus in Australian teaching hospitals, 1989-1999

An annual survey of antimicrobial resistance in clinical isolates of Staphylococcus aureus was conducted in 21 Australian teaching hospital microbiology laboratories in eight major cities from 1989 to 1999. A total of 19,000 isolates were tested for susceptibility to 18 antimicrobials, with 3795 being methicillin-resistant (MRSA). Resistance to ciprofloxacin in MRSA increased from 4.9% to 75.9%. The proportion of MRSA resistant to erythromycin decreased significantly (99.0%-88.9%), as did that to trimethoprim (98.4%-82.4%) and to tetracycline (96.5%-80.1%). The proportion of MRSA isolated increased in Sydney, Melbourne, Canberra, Adelaide, Perth, and Darwin, but not in Brisbane. The proportion in Hobart peaked in 1994. MRSA in Perth were predominantly non-multiresistant (nmMRSA) throughout the survey (i.e., resistant to less than three of eight indicator antibiotics) due mainly to local strains that originated in the community. The proportion of nmMRSA increased to modest levels in the other cities. In eastern cities, this was due to the appearance of strains closely related to nmMRSA seen in other countries of the southwestern Pacific.     

Recurrent community-acquired methicillin-resistant Staphylococcus aureus infections in an HIV-infected person

HIV-infected persons are at heightened risk for recurrent community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections, but there are limited data regarding the molecular characterization of these events. We describe an HIV-infected patient with 24 soft tissue infections and multiple colonization events. Molecular genotyping from 33 nonduplicate isolates showed all strains were USA300, Panton-Valentine leukocidin (PVL) and arginine catabolic mobile element (ACME) positive, and genetically related.     

Staphylococcus aureus infections in psittacine birds

Staphylococcus aureus was isolated from internal organs of 13 different psittacine birds submitted for necropsy over a period of 6 years. The birds all had lesions consistent with septicaemia. S. aureus isolates included three different phage types. In seven of the 13 birds, concurrent infections with Chlamydophila species, Enterococcus hirae, Candida species, unidentified streptococci and coagulasenegative staphylococci were detected. One bird also had lesions of lymphoid leucosis. Few indications were found that staphylococcosis associated problems may spread epidemically. The present studies suggest that S. aureus is pathogenic for psittacine birds, although it does not seem to be a frequent cause of disease.     

Can we do better in controlling and preventing methicillin-resistant Staphylococcus aureus (MRSA) in the intensive care unit (ICU)?

Methicillin-resistant Staphylococcus aureus (MRSA) is prevalent in many hospitals, but many of its most serious clinical manifestations, such as bloodstream infection and ventilator-associated pneumonia, are seen in the intensive care unit (ICU). Many interventions to prevent and control MRSA were initially pioneered in the ICU and subsequently extended to the rest of the hospital. Recent studies confirm how many of these are effective. Active surveillance reveals higher numbers of cases when compared with the sole use of clinical specimens to identify MRSA-positive patients. Although one recent study from the UK has suggested that isolation has no impact on MRSA transmission in the ICU, current recommendations include isolation or cohorting, combined with decolonisation (e.g., mupirocin to the nose and chlorhexidine baths) as major control measures. However, the excessive use of mupirocin for nasal MRSA decolonisation leads to resistance. Improved compliance with hand hygiene recommendations and better antibiotic stewardship are also important. Rapid diagnosis such as PCR may utilise isolation facilities more effectively by identifying MRSA patients earlier. However, all these measures must be combined with adequate numbers of staff and suitable space and facilities, e.g., single rooms, to be maximally effective. Finally, while much can be done within the ICU itself, MRSA in the ICU often reflects the difficulties elsewhere in the acute hospital and the health service generally, in terms of the control and prevention of healthcare-associated infection.     

Community-acquired methicillin-resistant Staphylococcus aureus infections: an emerging threat in Spain

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has not been recognised previously as a cause of MRSA infections in Spain. Nineteen patients carrying Panton–Valentine leukocidin (PVL)-positive MRSA were identified in a Barcelona hospital, of whom 15 were immigrants, mostly from South America. Twelve developed skin and soft-tissue infections. The associated isolates carried the PVL gene and staphylococcal chromosomal cassette (SCC) mec IV. A dominant clone belonging to sequence type (ST)8 and related to the USA300 clone was identified by pulsed-field gel electrophoresis. This clone is emerging in Spain, primarily among immigrants from South America, but dissemination to the native Spanish population could increase.     

Emergence and control of an outbreak of infections due to Panton-Valentine leukocidin positive,ST22 methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit

Methicillin resistant Staphylococcus aureus (MRSA) infection can cause significant morbidity and mortality in neonates. We investigated a nosocomial MRSA outbreak in a neonatal intensive care unit (NICU), using a novel typing method. Following two fatal cases, in May 2011, a prospective outbreak investigation was conducted, involving neonates, mothers and healthcare workers in a large tertiary NICU in Sydney. MRSA isolates were characterized by antimicrobial susceptibility testing, a multiplex PCR-based reverse line blot (mPCR/RLB) binary typing system and other molecular typing methods. Over 7 months, 14 neonates were colonized with MRSA and six infected: three with superficial lesions and three with life-threatening disease, including the two index cases, who died despite empirical treatment with vancomycin. Isolates from 15 neonates were indistinguishable by RLB typing and identified as a PVL-producing ST22 SCCmec IV MRSA strain, which was resistant to gentamicin and trimethoprim-sulphamethoxazole. The outbreak strain was also isolated from one healthcare worker, one environmental swab and one father, but the source remained obscure. During the same period several different non-multiresistant and multiresistant MRSA strains were isolated from five neonates, five mothers (including two whose infants were colonized with the outbreak strain), one father, three healthcare workers and two environmental swabs. Rapid turnaround time of typing results allowed us to recognize and define the outbreak and implement targeted infection control interventions. PVL-producing ST22 SCCmec IV MRSA appears to be a virulent and highly transmissible pathogen in the NICU, which was difficult to control.     

Methicillin resistance in Staphylococcus aureus infections among patients colonized with methicillin-susceptible Staphylococcus aureus

Objectives

We have noticed that patients colonized with methicillin-susceptible Staphylococcus aureus (MSSA) rarely get methicillin-resistant S. aureus (MRSA) infections. The purpose of this study was to compare the odds of a Staphylococcus aureus (SA) infection being an MRSA infection in MSSA carriers, MRSA carriers and non-carriers of SA.