Antibiotic control of antibiotic resistance in hospitals: a simulation study

<p>Abstract</p> <p>Background</p> <p>Using mathematical deterministic models of the epidemiology of hospital-acquired infections and antibiotic resistance, it has been shown that the rates of hospital-acquired bacterial infection and frequency of antibiotic infections can be reduced by (i) restricting the admission of patients colonized with resistant bacteria, (ii) increasing the rate of turnover of patients, (iii) reducing transmission by infection control measures, and (iv) the use of second-line drugs for which there is no resistance. In an effort to explore the generality and robustness of the predictions of these deterministic models to the real world of hospitals, where there is variation in all of the factors contributing to the incidence of infection, we developed and used a stochastic model of the epidemiology of hospital-acquired infections and resistance. In our analysis of the properties of this model we give particular consideration different regimes of using second-line drugs in this process.</p> <p>Methods</p> <p>We developed a simple model that describes the transmission of drug-sensitive and drug-resistant bacteria in a small hospital. Colonized patients may be treated with a standard drug, for which there is some resistance, and with a second-line drug, for which there is no resistance. We then ran deterministic and stochastic simulation programs, based on this model, to predict the effectiveness of various treatment strategies.</p> <p>Results</p> <p>The results of the analysis using our stochastic model support the predictions of the deterministic models; not only will the implementation of any of the above listed measures substantially reduce the incidences of hospital-acquired infections and the frequency of resistance, the effects of their implementation should be seen in months rather than the years or decades anticipated to control resistance in open communities. How effectively and how rapidly the application of second-line drugs will contribute to the decline in the frequency of resistance to the first-line drugs depends on how these drugs are administered. The earlier the switch to second-line drugs, the more effective this protocol will be. Switching to second-line drugs at random is more effective than switching after a defined period or only after there is direct evidence that the patient is colonized with bacteria resistant to the first antibiotic.</p> <p>Conclusions</p> <p>The incidence of hospital-acquired bacterial infections and frequencies of antibiotic resistant bacteria can be markedly and rapidly reduced by different readily implemented procedures. The efficacy using second line drugs to achieve these ends depends on the protocol used for their administration.</p

Why do paediatricians prescribe antibiotics? Results of an Italian regional project

<p>Abstract</p> <p>Background</p> <p>To investigate determinants of antibiotic prescription in paediatric care, as a first step of a multilevel intervention to improve prescribing for common respiratory tract infections (RTIs) in a northern Italian region with high antibiotic prescription rate.</p> <p>Methods</p> <p>A two-step survey was performed: in phase I, knowledge, and attitudes were explored involving all family and hospital paediatricians of Emilia-Romagna and a sample of parents. In phase II, patient care practices were explored in a stratified random sample of visits, both in hospitals and family physician's clinics; parent expectations were investigated in a sub-sample of these visits.</p> <p>Results</p> <p>Out of overall 4352 visits for suspected RTIs, in 38% of children an antibiotic was prescribed. Diagnostic uncertainty was perceived by paediatricians as the most frequent cause of inappropriate prescription (56% of 633 interviewed paediatricians); but, rapid antigen detecting tests was used in case of pharyngitis/pharyngotonsillitis by 36% and 21% of family and hospital paediatricians only. More than 50% of paediatricians affirmed to not adopt a "wait and see strategy" in acute otitis. The perceived parental expectation of antibiotics was not indicated by paediatricians as a crucial determinant of prescription, but this perception was the second factor most strongly associated to prescription (OR = 12.8; 95% CI 10.4 - 15.8), the first being the presence of othorrea. Regarding parents, the most important identified factors, potentially associated to overprescribing, were the lack of knowledge of RTIs and antibiotics (41% of 1029 parents indicated bacteria as a possible cause of common cold), and the propensity to seek medical care for trivial infections (48% of 4352 children accessing ambulatory practice presented only symptoms of common cold).</p> <p>Conclusion</p> <p>A wide gap between perceived and real determinants of antibiotic prescription exists. This can promote antibiotic overuse. Inadequate parental knowledge can also induce inappropriate prescription. The value of this study is that it simultaneously explored determinants of antimicrobial prescribing in an entire region involving both professionals and parents.</p

Decolonisation of MRSA, S. aureus and E. coli by Cold-Atmospheric Plasma Using a Porcine Skin Model In Vitro

In the last twenty years new antibacterial agents approved by the U.S. FDA decreased whereas in parallel the resistance situation of multi-resistant bacteria increased. Thus, community and nosocomial acquired infections of resistant bacteria led to a decrease in the efficacy of standard therapy, prolonging treatment time and increasing healthcare costs. Therefore, the aim of this work was to demonstrate the applicability of cold atmospheric plasma for decolonisation of Gram-positive (Methicillin-resistant Staphylococcus aureus (MRSA), Methicillin-sensitive Staphylococcus aureus) and Gram-negative bacteria (E. coli) using an ex vivo pig skin model. Freshly excised skin samples were taken from six month old female pigs (breed: Pietrain). After application of pure bacteria on the surface of the explants these were treated with cold atmospheric plasma for up to 15 min. Two different plasma devices were evaluated. A decolonisation efficacy of 3 log10 steps was achieved already after 6 min of plasma treatment. Longer plasma treatment times achieved a killing rate of 5 log10 steps independently from the applied bacteria strains. Histological evaluations of untreated and treated skin areas upon cold atmospheric plasma treatment within 24 h showed no morphological changes as well as no significant degree of necrosis or apoptosis determined by the TUNEL-assay indicating that the porcine skin is still vital. This study demonstrates for the first time that cold atmospheric plasma is able to very efficiently kill bacteria applied to an intact skin surface using an ex vivo porcine skin model. The results emphasize the potential of cold atmospheric plasma as a new possible treatment option for decolonisation of human skin from bacteria in patients in the future without harming the surrounding tissue

Frequency and antimicrobial resistance patterns of bacteria implicated in community urinary tract infections: a ten-year surveillance study (2000-2009)

BACKGROUND Urinary tract infection (UTI) is one of the most common infectious diseases at the community level. In order to assess the adequacy of the empirical therapy, the prevalence and the resistance pattern of the main bacteria responsible for UTI in the community (in Aveiro, Portugal) was evaluated throughout a ten-year period. METHODS In this retrospective study, all urine samples from patients of the District of Aveiro, in ambulatory regime, collected at the Clinical Analysis Laboratory Avelab during the period 2000-2009 were analysed. Samples with more than 105 CFU/mL bacteria were considered positive and, for these samples, the bacteria were identified and the profile of antibiotic susceptibility was characterized. RESULTS From the 155597 samples analysed, 18797 (12.1%) were positive for bacterial infection. UTI was more frequent in women (78.5%) and its incidence varied with age, affecting more the elderly patients (38.6%). Although E. coli was, as usual, the most common pathogen implicated in UTI, it were observed differences related to the other bacteria more implicated in UTI relatively to previous studies. The bacteria implicated in the UTI varied with the sex of the patient, being P. aeruginosa a more important cause of infection in men than in women. The incidence of the main bacteria changed over the study period (P. aeruginosa, Klebsiella spp and Providencia spp increased and Enterobacter spp decreased). Although E. coli was responsible for more than an half of UTI, its resistance to antibiotics was low when compared with other pathogens implicated in UTI, showing also the lowest percentage of multidrug resistant (MDR) isolates (17%). Bacteria isolated from females were less resistant than those isolated from males and this difference increased with the patient age. CONCLUSIONS The differences in sex and age must be taken into account at the moment of empirical prescription of antimicrobials. From the recommended antimicrobials by the European Association of Urology guidelines, the first line drugs (pivmecillinam and nitrofurantoin) and the alternative antibiotic amoxicillin-clavulanic acid (AMX-CLA) are appropriate to treat community-acquired UTI, but the fluoroquinolones should not be suitable to treat male infections and the trimethoprim-sulfamethoxazole (SXT) shall not be used in the treatment of UTI at this level.Thanks are due to the University of Aveiro, Centre for Environmental and Marine Studies (CESAM) for funding the Microbiology Research Group (Project Pest-C/MAR/LA0017/2011) and to Clinical Analysis Laboratory Avelab (Portugal) for supplying the data.publishe

[Antibiotic microbial resistance surveillance in invasive infections caused by Streptococcus pneumoniae and Staphylococcus aureus: the EARSS (European Antimicrobial Resistance Surveillance System) project in Italy (April 1999-April 2000)].

This paper presents the results of an Italian multicentric study conducted in the period April 1999-April 2000 in 64 clinical microbiology laboratories, aimed at collecting antimicrobial resistance data using a standard European protocol (EARSS Project, European Antimicrobial Surveillance System). A total of 1701 strains of Staphylococcus aureus were isolated from blood and 367 strains of Streptococcus pneumoniae were isolated from blood (72.7%) or from CSF (27.3%). Methicillin resistance in S. aureus was found to be 42.1%; it was significantly higher in adults (RR = 6.6, CI 95% 2.5-17.0), in hospitals of Centre and North of Italy (respectively RR = 1.45, CI 95% 1.1-2.0; RR = 1.6, CI 95% 1.1-2.2), and in intensive care and surgery units (respectively RR = 1.8, IC 95% 1.6-2.0 and RR = 1.7, CI 95% 1.4-1.9). Penicillin resistance in S. pneumoniae was found to be 12.1%; it was higher in South Italy (RR = 3.5, CI 95% 1.9-6.6, in meningitis compared to sepsis (RR = 2.5, CI 95% 1.4-2.5) and in intensive care units compared to other departments (RR = 2.2, CI 95% 1.0-4.8). The level of erythromycin resistance in S. pneumoniae was of 28.2%, reaching 56.4% in penicillin resistant strains. These results suggest that a continued surveillance and effective control measures are required

Inferring the potential success of pneumococcal vaccination in Italy: serotypes and antibiotic resistance of Streptococcus pneumoniae isolates from invasive diseases.

To evaluate the potential impact of antipneumococcal vaccination in Italy, Streptococcus pneumoniae isolates from invasive disease were collected from 65 laboratories in the years 1997-2000. Of the 503 isolates examined, 15% were from children or = 65 years. The most frequent serogroups were, in ranking order, 14, 19, 6, and 23. Overall, 93.8% of the isolates belonged to serogroups enclosed in the 23-valent polysaccharide vaccine. Among children isolates, serotypes 14, 6B, and 23F comprised 60% of the isolates; overall, 72% of the isolates belonged to serotypes included in the heptavalent conjugate vaccine. Penicillin nonsusceptible isolates (10%) belonged to a limited number of serogroups, being more common in serogroups 19 and 9 and in the nonvaccine serogroups 24 and 35. Erythromycin-resistant isolates (29%) belonged to several serogroups, more frequently to serogroups 14, 6, and 19. Both vaccines are potentially able to prevent the majority of resistant infections in the respective age groups in Italy