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Title: Staphylococcus aureus infections among Polish patients of selected hospitals and care institutions


Hospital infections are an important cause of morbidity and mortality worldwide, especially if the etiological factor is drug-resistant microorganisms, also in Europe in recent decades there has been steady increase in nosocomial infections caused by bacteria resistant to antibiotics. Therefore, drug resistance of microorganisms is one of the most serious public health problems today. It is a consequence of the increasing selective pressure of antibiotics and chemotherapeutics, their abuse and misuse. The share of multidrug resistant strains significantly limits the possibilities of therapeutic options and severely worsens the prognosis, especially when it concerns the population of the most vulnerable patients, including patients of geriatric wards or neonatal intensive care. The multidrug resistance phenomenon is a global problem concerning bacteria occurring both in the hospital and in the non-hospital population.Staphylococus aureus is a component of human commensal flora. It colonizes mucous membranes, including the skin, and at the same time, having at its disposal various pathogenic factors determining pathogenicity and mechanisms of resistance to antibacterial drugs, is one of the most dangerous bacterial pathogens that cause human infection. The strains of these microorganisms have the potential to produce various toxins and other virulence factors that facilitate bacterial growth and adverse effects on the host organism. Low birth weight, immaturity of the immune barrier, initially severe condition of hospitalized, invasive methods of therapy and monitoring of patients mainly: intubation and vascular lines are factors conducive to the development of infections. The clinical picture of staphylococcal infection is associated with the possibility of producing various virulence factors including.The conducted research allowed to describe in detail the epidemiology of infections with S.aureus aetiology in southern Poland. Epidemiological analysis was carried out in various analytical areas, such as: type of care of a patient with infections (hospital/LTCF), a patient with infection (operated patients/newborns\geriatric patients), clinical form of infection.Operated patients: In 2004, in the examined trauma and orthopaedic units 1095 surgical treatments were carried out, treatments with the use of implants accounted for 53%, with a morbidity of SSI of 2.6% in total, 67.7% of surgical site infection of total hip replacements cases concerned patients that underwent knee or hip arthroplasty and others. Superficial infections constituted a majority (65%), however, deep and organ damages were only found after prosthetic surgery. Two deaths of patients with a diagnosis of SSI were found to be indirectly affected by infection of mixed aetiology. Among etiological factors of all the clinical forms of the SSI, a dominant part was consisted of S.aureus (65.4%) of which 31,3% were resistant to methicillin. Additionally, they showed resistance to gentamicin at a frequency of 54,8%, or ciprofloxacin in 30%, the lack of sensitivity to fusidic acid showed 6.5% of the studied strains, all remained susceptible to vancomycin and fusidic acid ; The resistance of MRSA strains was associated with the lack of sensitivity to aminoglycosides (81%), lincosamides and fluoroquinolones (50.6%). In 2005, it was decided to focus only on hip replacement surgeries which were associated with the highest risk of infection, 479 hip prosthesis patients and 172 patients after knee prosthesis underwent the analysis. Morbidity was found to be 2.3% and 7.0%, respectively. Among many examined, the only significant factor affecting the risk of infection was the length of the surgery - and only in relation to total knee arthroplasty, ICD-9: 81.54 (T=2.009, p<0.05). Reoperations were necessary in half of patients diagnosed with SSI after hip replacement and 33.3% of patients after knee replacement. After applying the SSI risk index, the significantly higher risk of SSI after surgery in the knee area was found compared to the reference data. In the analysed period, microbiological confirmation was obtained in 62% of SSI cases, and the share of S.aureus after hip surgery was 16.7%, while after knee replacement: 40.0%. No MRSA strain was identified and gentamycin resistant strains accounted for 20%, against ciprofloxacin and fusidic acid: 10% of strains. All of them were sensitive to vancomycin.Newborns with very low birth weight: S.aureus was an etiological factor in 6,5% of infections cases (total: early+late), most often in blood infections (55.2%) and pneumonia (39.7%). The MRSA phenotype was found in 32.8%, insignificantly more frequent in blood infections. The MRSA phenotype was significantly related to time, i.e. it was related to infections detected on average on the 14th day (vs. 23 days for MSSA, p = 0.0194). Multivariate analysis did not show a relationship between the phenotype and the clinical form of the infection or the clinical condition of the newborn. Antibiotic consumption expressed as the duration of therapy (DOT) and defined daily doses (DDD) associated with the treatment of S. aureus infections was not significantly dependent on the phenotype: DOT for MSSA: 11.2 and MRSA 12.3 and DDD respectively: 30.2 and 26.0. A significant difference in consumption was found only in relation to DOT for β-lactams: Z=-2.8, p= 0.005; for MRSA, the average is 3.5; SD 1.37; median 3,5, max 5; for MSSA, average 7.8; SD 4.15; median 7; max 21. The tested strains were not characterized by significantly high resistance or virulence ; of infection) in 17.6% of residents. The risk of colonization (presence in the wound or vestibule of the nose) was significantly related to the type of care (ZOL vs. DPS) and the general stats of the resident: the presence of urinary or catheter incontinence in the urinary bladder, feeding by gavage, and particularly low Barthel score and mobility restrictions. For the S.aureus infection the following factors were also significantly important: previous colonization of MRSA, and the presence of chronic wounds, especially leg ulcers. Multivariate analysis indicated that the risk of MRSA was remarkably associated with: age, physical activity and chronic wounds. Residents with MRSA were highly more often hospitalized due to infections, than those with the MSSA phenotype. S.aureus strains isolated from infections were significantly resistant to fluoroquinolones, tobramycin and amikacin.In total, from various forms of infections isolated from neonatal patients and long-term care residents 49 strains were with the MRSA phenotype. Genetic typing was carried out with the use of a pulse electrophoresis method PFGE. Strains from neonatal infections (MSSA and MRSA) and MRSA strains from long-term care residents (colonization and/or infection) were subjected to this method. Strains isolated from newborns were additionally catalogued by the spa-typing method and the type of chromosomal SCCmec cassette was identified.PFGE typing showed that the majority of MRSA strains isolated from neonatal infections were characterised by unique pulsotypes. The vast majority of MRSA strains (14 out of 16) had an identical pulsotype, they were included in one clone. Strains with identical pulsotypes came from the NICU department of one hospital. In PFGE analysis of MRSA strains derived from LTCF residents (n=33) 5 major clonal groups were detected. The most frequent one was pulsotype A, it was demonstrated in 14 strains.The spa gene from 16 MRSA strains was sequenced with the use of spa-typing. The most common spa type was t015, it occurred in 15 of the tested strains. One strain had the type spa t011. The type of chromosomal cassette SCCmec within which the mecA gene responsible for the MRSA phenotype is coded was also specified in MRSA isolates. The most frequently detected type of chromosomal cassette is SCCmec IV. By comparing the results obtained with different genotyping methods, it was shown that among the tested neonatal MRSA isolates, the isolates with the t015 spa type and the SCCmecIV are the largest group.So far, in Poland there have been realized no multicentre studies concerning MRSA nosocomial infections, the presented data are the first to concern such key populations as neonatology and geriatrics in modern medicine. It was found:1 ; The incidence of SSIs of hip prosthesis in our study was comparable to the incidence in the German KISS, and in the American NHSN program where surveillance is integrating a highly sensitive postdischarge detection. On the other hand, we observed a higher, statistically significant cumulative incidence in case of knee endoarthroplasty. Microbiology and drug resistance of etiological factors of infectionsafter the implementation of surveillance (ie 2004-2005) did not differ from those described in other multi-center programs in the world.2. The general condition of residents has a significant impact at the risk of infections of MRSA aetiology in long-term care - people with limited mobility (lying, self-changing positions or not) transferred transfer to other medical facilities , i.e. a hospital, a dialysis center should be subject to special supervision including contact insulation. The risk of MRSA presence did not depend on the age of residents. In case of necessity of the screening tests, focus on high risk populations should be recommended – according to the conducted analyzes. The Barthel scale may be the determinant (target screening), which significantly reduces the cost of the procedures3. There is no association of MRSA phenotypes with the length of VLBW newborns hospitalization, which means the risk of such infections, even in the first days of life. Horizontal transmission of MRSA strains has also been observed - which indicates a strong influence of intensive departments Neonatal therapy work organization and principles of cooperation with neonatal caregivers (parents) for the risk of transmission of infections.4. The high consumption of glycopeptides in the treatment of MSSA infections indicates the need to improve drug management in the examined wards (antimicrobial stewardship) and the introduction of research based on rapid methods, eg genetic methods for early detection of the infection aetiology and the implementation of targeted antimicrobial therapy.5. A large diversity of identified genotypes, among others in the PFGE method, which indicates a strong penetration of non-hospital and hospital environment, which proves that drug resistant strains occur not only in a closed health care of hospital but simultaneously in long-term care facilities.

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2 - studia doktoranckie

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Uniwersytet Jagielloński. Collegium Medicum. Wydział Lekarski.


Jadwiga Wójkowska-Mach ; Agnieszka Chmielarczyk

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Biblioteka Medyczna Uniwersytetu Jagiellońskiego- Collegium Medicum

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Mar 12, 2021

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Jun 30, 2020

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ZB-130754 Mar 12, 2021


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