High antibiotic susceptibility among bacterial pathogens in Swedish ICUs. Report from a nation-wide surveillance program using TA90 as a novel index of susceptibility

Global mapping of antibiotic resistance rates among clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis

INTRODUCTION

Infections caused by Stenotrophomonas maltophilia are clinically important due to its intrinsic resistance to a broad range of antibiotics. Therefore, selecting the most appropriate antibiotic to treat S. maltophilia infection is a major challenge.

AIM

The current meta-analysis aimed to investigate the global prevalence of antibiotic resistance among S. maltophilia isolates to the develop more effective therapeutic strategies.

METHOD

A systematic literature search was performed using the appropriate search syntax after searching Pubmed, Embase, Web of Science and Scopus databases (May 2023). Statistical analysis was performed using Pooled and the random effects model in R and the metafor package. A total of 11,438 articles were retrieved. After a thorough evaluation, 289 studies were finally eligible for inclusion in this systematic review and meta-analysis.

RESULT

Present analysis indicated that the highest incidences of resistance were associated with doripenem (97%), cefoxitin (96%), imipenem and cefuroxime (95%), ampicillin (94%), ceftriaxone (92%), aztreonam (91%) and meropenem (90%) which resistance to Carbapenems is intrinsic. The lowest resistance rates were documented for minocycline (3%), cefiderocol (4%). The global resistance rate to TMP-SMX remained constant in two periods before and after 2010 (14.4% vs. 14.6%). A significant increase in resistance to tigecycline and ceftolozane/tazobactam was observed before and after 2010.

CONCLUSIONS

Minocycline and cefiderocol can be considered the preferred treatment options due to low resistance rates, although regional differences in resistance rates to other antibiotics should be considered. The low global prevalence of resistance to TMP-SMX as a first-line treatment for S. maltophilia suggests that it remains an effective treatment option.

Global prevalence and distribution of antibiotic resistance among clinical isolates of Stenotrophomonas maltophilia: A systematic review and meta-analysis

OBJECTIVES

Stenotrophomonas maltophilia (S. maltophilia), an opportunistic pathogen, causes infection in patients undergoing immunosuppressive therapy, mechanical ventilation, or catheters and in long-term hospitalized patients. Due to its extensive resistance to various antibiotics and chemotherapeutic agents, S. maltophilia is challenging to treat. Using case reports, case series, and prevalence studies, the current study provides a systematic review and meta-analysis of antibiotic resistance profiles across clinical isolates of S. maltophilia.

METHODS

A systematic literature search was performed for original research articles published in Medline, Web of Science, and Embase databases from 2000 to 2022. Statistical analysis was performed using STATA 14 software to report antibiotic resistance of S. maltophilia clinical isolates worldwide.

RESULTS

223 studies (39 case reports/case series and 184 prevalence studies) were collected for analysis. A meta-analysis of prevalence studies demonstrated that the most antibiotic resistance worldwide was to levofloxacin, trimethoprim-sulfamethoxazole (TMP/SMX), and minocycline (14.4%, 9.2%, and 1.4%, respectively). Resistance to TMP/SMX (36.84%), levofloxacin (19.29%), and minocycline (1.75%) were the most prevalent antibiotic resistance types found in evaluated case reports/case series studies. The highest resistance rate to TMP/SMX was reported in Asia (19.29%), Europe (10.52%), and America (7.01%), respectively.

CONCLUSION

Considering the high resistance to TMP/SMX, more attention should be paid to patients' drug regimens to prevent the emergence of multidrug-resistant S. maltophilia isolates.

Growing consumption of antibiotics and epidemiology of Clostridioides difficile infections in Poland: A need to develop new solutions

Clostridioides (formerly Clostridium) difficile infections (CDIs) are becoming more common and more serious. C. difficile is the etiologic agent of antibiotic-associated diarrhea, pseudomembranous enterocolitis, and toxic megacolon while CDIs recur in 7.9% of patients. About 42.9 CDI cases/10,000 patient-days are diagnosed each day in Europe, whereas in Poland 5.6 CDI cases/10,000 patient-days are reported; however, the median for European countries is 2.9 CDI cases/10,000 patient-days. Epidemiology of CDIs has changed in recent years and risk of developing the disease has doubled in the past decade that is largely determined by use of antibiotics. Studies show that rate of antibiotic consumption in the non-hospital sector in Poland is much higher than the European average (27 vs. 21.8 DDD/1,000 patient-days), and this value has increased in recent years. Antibiotic consumption has also increased in the hospital sector, especially in the intensive care units - 1,520 DDD/1,000 patient-days (ranging from 620 to 3,960 DDD/1,000 patient-days) - and was significantly higher than in Germany 1,305 (ranging from 463 to 2,216 DDD/1,000 patient-days) or in Sweden 1,147 (ranging from 605 to 2,134 DDD/1,000 patient-days). The recent rise in CDI incidence has prompted a search for alternative treatments. Great hope is placed in probiotics, bacteriocins, monoclonal antibodies, bacteriophages, and developing new vaccines.

Consumption of Antibiotics and Epidemiology of Clostridioides difficile in the European Union in 2016-Opportunity for Practical Application of Aggregate ECDC Data

Background: The most important pathomechanism of Clostridioides difficile infections (CDI) is post-antibiotic intestinal dysbiosis. CDI affects both ambulatory and hospital patients. Aim: The objective of the study was to analyze the possibility of utilizing databases from the European Centre for Disease Prevention and Control subject to surveillance for the purpose of identifying areas that require intervention with respect to public health. Methods: The analysis encompassed data concerning CDI incidence and antibiotic consumption expressed as defined daily doses (DDD) and quality indicators for antimicrobial-consumption involving both ambulatory and hospital patients in 2016. Results: In 2016, in the European Union countries, total antibiotic consumption in hospital and outpatient treatment amounted to 20.4 DDD (SD 7.89, range 11.04–39.69); in ambulatory treatment using average of ten times more antibiotics than hospitals. In total, 44.9% of antibiotics used in outpatient procedures were broad-spectrum antibiotics. We have found a significant relationship between the quality of antibiotics and their consumption: The more broad-spectrum antibiotics prescribed, the higher the sales of antibiotics both in the community sector and in total. CDI incidence did not statistically significantly correlate with the remaining factors analyzed on a country-wide level. Conclusion: Antibiotic consumption and the CDI incidence may depend on many national variables associated with local systems of healthcare organization and financing. Their interpretation in international comparisons does not give clear-cut answers and requires caution.

Surveillance of Antibiotic Prescribing in Intensive Care Units in Poland

Antibiotic use and microbial resistance in health care-associated infections are increasing globally and causing health care problems. Intensive Care Units (ICUs) represent the heaviest antibiotic burden within hospitals, and sepsis is the second noncardiac cause of mortality in ICUs. Optimizing appropriate antibiotic treatment in the management of the critically ill in ICUs became a major challenge for intensivists. We performed a surveillance study on the antibiotic consumption in 108 Polish ICUs. We determined which classes of antibiotics were most commonly consumed and whether they affected the length of ICU stay and the size and category of the hospital. A total of 292.389 defined daily doses (DDD) and 192.167 patient-days (pd) were identified. Antibiotic consumption ranged from 620 to 3960 DDD/1000 pd. The main antibiotic classes accounted for 59.6% of the total antibiotic consumption and included carbapenems (17.8%), quinolones (14%), cephalosporins (13.7%), penicillins (11.9%), and macrolides (2.2%), respectively, whereas the other antibiotic classes accounted for the remainder (40.4%) and included antifungals (34%), imidazoles (20%), aminoglycosides (18%), glycopeptides (15%), and polymyxins (6%). The most consumed antibiotic classes in Polish ICUs were carbapenems, quinolones, and cephalosporins, respectively. There was no correlation between antibiotic consumption in DDD/1000 patient-days, mean length of ICU stay, size of the hospital, size of the ICU, or the total amount of patient-days. It is crucial that surveillance systems are in place to guide empiric antibiotic treatment and to estimate the burden of resistance. Appropriate use of antibiotics in the ICU should be an important public health care issue.

Trimethoprim/sulfamethoxazole for Acinetobacter spp.: A review of current microbiological and clinical evidence

Clinicians nowadays are confronted with an epidemic of multidrug-resistant (MDR) Acinetobacter infections and are forced to consider every treatment alternative, including older antibiotic agents, not conventionally used. This review aimed to evaluate the published evidence on the antimicrobial activity and clinical effectiveness of trimethoprim/sulfamethoxazole (TMP-SMX) against Acinetobacter spp. Selected in vitro studies included antimicrobial surveillance reports, microbiological studies regarding the activity of TMP-SMX against MDR Acinetobacter isolates, and clinical studies published after the year 2000. Non-susceptibility rates for Acinetobacter spp. in surveillance studies ranged from 4% to 98.2%; in 23 of 28 studies, non-susceptibility to TMP-SMX was >50% and in a subset of 15 studies non-susceptibility was >70%. In studies regarding MDR Acinetobacter spp., non-susceptibility rates ranged from 5.9% to 100%; however, 19 of 21 studies reported >70% non-susceptibility. Extensively drug-resistant Acinetobacter baumannii complex had total (100%) resistance in five of six studies. Carbapenem-resistant Acinetobacter spp. had non-susceptibility rates to TMP-SMX of >80% in 22 of 26 studies. One study on polymyxin-resistant A. baumannii showed a susceptibility rate of 54.2% (13/24). Only seven case reports evaluated TMP-SMX for Acinetobacter spp. infections, mainly in combination with other agents; all cases were deemed therapeutic successes. Although TMP-SMX is not usually active against Acinetobacter spp., it might be considered in cases where there are no other options.

Short- and long-term mortality in severe sepsis/septic shock in a setting with low antibiotic resistance: a prospective observational study in a Swedish university hospital

Background: There is little epidemiologic data on sepsis, particularly in areas of low antibiotic resistance. Here we report a prospective observational study of severe sepsis and septic shock in patients admitted to the Intensive Care Unit (ICU) at Karolinska University Hospital, Sweden. We aimed to evaluate short- and long-term mortality, and risk factors for sepsis-related death. A second aim was to investigate patient care in relation to gender.

Methods: One hundred and one patients with severe sepsis and septic shock, admitted to the ICU between 2005 and 2009, were prospectively enrolled in the study. Defined primary endpoints were day 28, hospital, and 1-year mortality. Risk factors for sepsis-related death was evaluated with a multivariate analysis in a pooled analysis with two previous sepsis cohorts. In the subset of patient admitted to the ICU through the emergency department (ED), time to clinician evaluation and time to antibiotics were assessed in relation to gender.

Results: In the septic cohort, the day 28, hospital, and 1-year mortality rates were 19, 29, and 34%, respectively. Ninety-three percent of the patients received adequate antibiotics from the beginning. Multi-resistant bacteria were only found in three cases. Among the 43 patients admitted to the ICU through the ED, the median time to antibiotics was 86 min (interquartile range 52–165), and overall 77% received appropriate antibiotics within 2 h. Female patients received antibiotics significantly later compared to male patients (p = 0.047).

Conclusion: The results demonstrate relatively low mortality rates among ICU patients with severe sepsis/septic shock, as compared to reports from outside Scandinavia. Early adequate antibiotic treatment and the low incidence of resistant isolates may partly explain these findings. Importantly, a gender difference in time to antibiotic therapy was seen.

High incidence of post-injury pneumonia in intensive care-treated trauma patients

INTRODUCTION

Trauma patients are susceptible to post-injury infections. We investigated the incidence, as well as risk factors for development of pneumonia in intensive care unit (ICU)-treated trauma patients. In addition, we report pathogens identified in patients that developed pneumonia.

METHODS

The study cohort consisted of 322 trauma patients admitted to the ICU at a level-one trauma centre following initial resuscitation. Patients 15 years or older with an ICU stay of more than 24 h were included. We investigated pre-hospital and hospital parameters during the first 24 h after admission and their possible association with pneumonia within 10 days of ICU admission.

RESULTS

Majority of the patients were male (78%) and the median age was 41 years. The overall degree of injury was high with a median Injury Severity Score (ISS) of 24. Overall 30-day mortality was 9%. Eighty-five (26%) patients developed pneumonia during their first 10 days in the ICU. Univariate logistic regression revealed that intubation in the field, shock, Glasgow Coma Scale (GCS) 3-8, major surgery within 24 h after admission, massive transfusion and ISS > 24 were all risk factors for subsequent development of pneumonia. In the multivariable model, only GCS 3-8 was identified as an independent risk factor. In 42 out of the 85 cases of pneumonia, the diagnosis was defined by significant growth of at least one pathogen where Enterobacteriaceae and Staphylococcus aureus were the most common.

CONCLUSIONS

Pneumonia is a common complication among ICU-treated trauma patients. Reduced consciousness is an independent risk factor for development of pneumonia after severe injury.

Pathogens in the lower respiratory tract of intensive care unit patients: impact of duration of hospital care and mechanical ventilation

BACKGROUND

Ventilator-associated pneumonia (VAP), the most common hospital-acquired infection in intensive care unit (ICU) patients, is caused by bacteria in the lower respiratory tract of mechanically ventilated patients.

METHODS

The current study was focused on 443 bacterial isolates from the lower respiratory tract of mechanically ventilated ICU patients (n = 346) in a Swedish University Hospital. Data were obtained from a prospective infection control database covering 9 y (2002-2010). We analysed the correlation between duration of hospital care and mechanical ventilation at the time of sampling on the occurrence of different pathogens.

RESULTS

Duration of hospital care and mechanical ventilation prior to sampling was similarly short for Streptococcus pneumoniae, beta-streptococci, and Haemophilus influenzae (≤ 2 days). In contrast, duration of hospital care and mechanical ventilation were longest for Stenotrophomonas maltophilia (6 and 11 days). For Staphylococcus aureus, the most common Gram-positive isolate, the duration was longer than for S. pneumoniae but shorter than for most Gram-negative bacteria. With the exception of S. maltophilia and Pseudomonas aeruginosa, the median duration of mechanical ventilation was short and similar for most bacteria. In samples taken on the first day of mechanical ventilation, the rate of pathogens expected to be resistant to cefotaxime was 23%.

CONCLUSIONS

The occurrence of pathogens with high antibiotic resistance in the lower respiratory tract increases with increased duration of hospital care and mechanical ventilation. An equally important result is that pathogens resistant to third-generation cephalosporins were more common than expected, even after a very short duration of hospital care and mechanical ventilation.

Variations and determinants of antibiotic consumption in Hungarian adult intensive care units

PURPOSE

The aim of this work was to study the use of systemic antibacterials and its possible determinants in Hungarian intensive care units (ICUs).

METHODS

Hospital pharmacy. departments provided package level dispensing data for their corresponding ICU (2006). Data were converted into defined daily doses (DDDs) and expressed as DDD per 100 patient-days and DDD per 100 admissions. Antibiotics were ranked by volume of DDDs, and the agents responsible for 90% of total use (DU90%) were noted. To explore differences and relationships between antibiotic use and antibiotic policy elements/ICU characteristics, the analysis of variances or the Pearson correlation analysis was performed.

RESULTS

Valid data were obtained for 44 ICUs. Antibiotic use varied widely (from 27.9 to 167.8 DDD per 100 patient-days and from 104.7 to 1784.6 DDD per 100 admissions). In total, 11-34 different antibacterials per ICUs were used, of which, 5-15 were in the DU90% segment. The proportional use of parenteral agents ranged from 46.2 to 98.3%. The mean of overall antibiotic use was highest for penicillins with beta-lactamase inhibitors, followed by quinolones and third-generation cephalosporins. Of the studied factors, only the ICU category (i.e., level of care) showed significant association with total antibacterial use.

CONCLUSIONS

The striking differences in total antibiotic use and the extensive use of the oral agents in some ICUs may indicate room for improvement. As none of the antibiotic policy elements were accompanied by lower antibiotic use in the pooled analysis, it suggests that--beside the ICU category--other unrevealed factors determine antibiotic use.

ICU stay promotes enrichment and dissemination of multiresistant coagulase-negative staphylococcal strains

Patients in the intensive care unit (ICU) are prone to be colonized and infected by multi-resistant bacteria. It is previously known that nosocomial infections are often preceded by cross-transmission events. The aim of the present investigation was to study the impact of the patient's length of ICU stay on the resistance patterns, diversity and dissemination of coagulase-negative staphylococci (CoNS) within and between patients. Two groups of patients were studied, including 20 consecutive patients sampled within 2 h from admission (short-stayers, SS), and all patients treated for at least 5 d in the ICU (long-stayers, LS), available for sampling every second week (n = 15). Sampling was performed from 5 sites: oropharynx, nares, neck, axilla and perineum. A total of 868 CoNS isolates deriving from LS patients and 403 isolates from SS patients were analysed for antimicrobial susceptibility, clonal diversity and dissemination within and between patients. The highest resistance rates were seen for oxacillin and ciprofloxacin, being 92% and 83%, respectively. Long-stayers were at significantly higher risk of being colonized with CoNS isolates resistant against oxacillin, clindamycin, ciprofloxacin, gentamicin as well as with multiresistant strains. By genotyping 22 phenotypes that were shared among at least 2 patients, 32 PFGE types of which 16 colonized more than 1 individual were identified. One of the clones was isolated from 10 individuals, including 2 SS patients, indicating an epidemic strain. Prolonged ICU stay was significantly correlated to decreased clonal diversity, increased endogenous dissemination of resistant strains and cross-transmission. The results emphasize the importance of good infection control practice, especially in this vulnerable group of patients.

Antimicrobial activity of tigecycline and comparative agents against clinical isolates of staphylococci and enterococci from ICUs and general hospital wards at three Swedish university hospitals

The activities of tigecycline and comparative agents on staphylococci and enterococci isolated from patients at general hospital wards (GHWs) and intensive care units (ICUs) at 3 university hospitals in Sweden were investigated. Oxacillin disc diffusion and minimal inhibitory concentration with E-test were used. The presence of mecA, vanA or vanB genes was determined with PCR. Statistically significant higher incidence of clindamycin, fusidic acid, rifampicin and multidrug-resistant CoNS was found at ICUs compared to GHWs. Resistance rates were low among S. aureus. Tigecycline, linezolid and vancomycin were the only agents with high activity against methicillin-resistant S. aureus and multidrug-resistant CoNS. Resistance rates were low among E. faecalis, except for high-level gentamicin-resistant (HLGR) E. faecalis. E. faecium showed high resistance rates to ampicillin, piperacillin/tazobactam and imipenem. The HLGR rates among E. faecium were lower than the rates for E. faecalis. Tigecycline and linezolid were the only drugs with high activity against all enterococci including vancomycin-resistant enterococci. No statistically significant differences in susceptibility rates were found between the ward levels for S. aureus and enterococcal isolates and no statistically significant differences were found between the hospitals.

Antibiotic susceptibility patterns and clones of Pseudomonas aeruginosa in Swedish ICUs

Pseudomonas aeruginosa is 1 of the bacteria most adaptive to anti-bacterial treatment. Previous studies have shown nosocomial spread and transmission of clonal strains of P. aeruginosa in European hospitals. In this study we investigated antibiotic susceptibility and clonality in 101 P. aeruginosa isolates from 88 patients admitted to 8 Swedish ICUs during 2002. We also compared phenotypes and genotypes of P. aeruginosa and carried out cluster analysis to determine if phenotypic data can be used for surveillance of clonal spread. All isolates were collected on clinical indication as part of the NPRS II study in Sweden and were subjected to AFLP analysis for genotyping. 68 isolates with unique genotypes were found. Phenotyping was performed using MIC values for 5 anti-pseudomonal agents. Almost 6% of the isolates were multi-drug resistant (MDR), and this figure rose to almost 8% when intermediate isolates were also included. We found probable clonal spread in 9 cases, but none of them was found to be an MDR strain. Phenotypical cluster analysis produced 40 clusters. Comparing partitions did not demonstrate any significant concordance between the typing methods. The conclusion of our study is that cross-transmission and clonal spread of MDR P. aeruginosa does not present a clinical problem in Swedish ICUs, but probable cross-transmission of non-MDR clones indicate a need for improved hygiene routines bedside. The phenotype clusters were not concordant with genotype clusters, and genotyping is still recommended for epidemiological tracking.

Surveillance of microbial resistance in European Intensive Care Units: a first report from the Care-ICU programme for improved infection control

PURPOSE

To report initial results from a European ICU surveillance programme focussing on antibiotic consumption, microbial resistance and infection control.

METHODS

Thirty-five ICUs participated during 2005. Microbial resistance, antibiotic consumption and infection control stewardship measures were entered locally into a web-application. Results were validated locally, aggregated by project leaders and fed back to support local audit and benchmarking.

RESULTS

Median (range) antibiotic consumption was 1,254 (range 348-4,992) DDD per 1,000 occupied bed days. The proportion of MRSA was median 11.6% (range 0-100), for ESBL phenotype of E. coli and K. pneumoniae 3.9% (0-80) and 14.3% (0-77.8) respectively, and for carbapenem-resistant P. aeruginosa 22.5% (0-100). Screening on admission for alert pathogens was commonly omitted, and there was a lack of single rooms for isolation.

CONCLUSIONS

The surveillance programme demonstrated wide variation in antibiotic consumption, microbial resistance and infection control measures. The programme may, by providing rapid access to aggregated results, promote local and regional audit and benchmarking of antibiotic use and infection control practices.

Molecular and descriptive epidemiologyof multidrug-resistant Enterobacteriaceae in hospitalized infants

OBJECTIVE

To investigate the epidemiology of multidrug-resistant Enterobacteriaceae (MDRE) in hospitalized infants.

METHODS

From 2000 through 2005, active surveillance cultures for MDRE were performed for patients admitted to a 40-bed neonatal intensive care unit (NICU) that provides care for critically ill infants 6 months of age or younger. MDRE epidemiology and the genetic relatedness of MDRE strains determined by repetitive-sequence polymerase chain reaction were analyzed.

RESULTS

Active surveillance cultures revealed that 759 (23%) of 3,370 NICU infants (or approximately 1 in 5) developed MDRE colonization or infection and that 613 (72%) of the 853 isolates with epidemiologic data available were healthcare acquired. MDRE colonization occurred more frequently (in 653 infants [86%]) than did MDRE infection (in 106 [14%]). Of the 653 infants with MDRE colonization, 119 (18%) eventually became infected, with 29 (4%) acquiring sterile site infections. The most commonly isolated organisms were the Enterobacter species, accounting for 612 (71%) of the 862 isolates. Molecular epidemiologic analysis revealed that genetic-relatedness clustering (related clusters defined as having a genetic similarity coefficient greater than 95%) varied depending on microbial species. Clustering was detected for 36 (78%) of the 46 Enterobacter aerogenes isolates, 22 (45%) of the 49 Enterobacter cloacae isolates, and 13 (59%) of the 22 Klebsiella pneumoniae isolates.

CONCLUSION

Hospitalized infants are at significant risk of acquiring MDRE, specifically Enterobacter species, at the study institution. Active surveillance cultures identified colonized patients who likely contributed to the institutional reservoir of MDRE. Molecular epidemiologic studies suggest that both patient-to-patient transmission and de novo acquisition of resistance play a role in the acquisition of these organisms, and that the clinical significance of such acquisition varies by species. The high percentage of E. aerogenes isolates that demonstrated genetic clustering suggests that monitoring the prevalence of this organism could serve as a useful measure of compliance with infection control procedures.

Sustained reduction of antibiotic use and low bacterial resistance: 10-year follow-up of the Swedish Strama programme

Increasing use of antibiotics and the spread of resistant pneumococcal clones in the early 1990s alarmed the medical profession and medical authorities in Sweden. Strama (Swedish Strategic Programme for the Rational Use of Antimicrobial Agents and Surveillance of Resistance) was therefore started in 1994 to provide surveillance of antibiotic use and resistance, and to implement the rational use of antibiotics and development of new knowledge. Between 1995 and 2004, antibiotic use for outpatients decreased from 15.7 to 12.6 defined daily doses per 1000 inhabitants per day and from 536 to 410 prescriptions per 1000 inhabitants per year. The reduction was most prominent in children aged 5-14 years (52%) and for macrolides (65%). During this period, the number of hospital admissions for acute mastoiditis, rhinosinusitis, and quinsy (peritonsillar abscess) was stable or declining. Although the epidemic spread in southern Sweden of penicillin-resistant Streptococcus pneumoniae was curbed, the national frequency increased from 4% to 6%. Resistance remained low in most other bacterial species during this period. This multidisciplinary, coordinated programme has contributed to the reduction of antibiotic use without measurable negative consequences. However, antibiotic resistance in several bacterial species is slowly increasing, which has led to calls for continued sustained efforts to preserve the effectiveness of available antibiotics.

Acinetobacter infections: a growing threat for critically ill patients

There has been increasing concern regarding the rise of Acinetobacter infections in critically ill patients. We extracted information regarding the relative frequency of Acinetobacter pneumonia and bacteraemia in intensive-care-unit (ICU) patients and the antimicrobial resistance of Acinetobacter isolates from studies identified in electronic databases. Acinetobacter infections most frequently involve the respiratory tract of intubated patients and Acinetobacter pneumonia has been more common in critically ill patients in Asian (range 4-44%) and European (0-35%) hospitals than in United States hospitals (6-11%). There is also a gradient in Europe regarding the proportion of ICU-acquired pneumonias caused by Acinetobacter with low numbers in Scandinavia, and gradually rising in Central and Southern Europe. A higher proportion of Acinetobacter isolates were resistant to aminoglycosides and piperacillin/tazobactam in Asian and European countries than in the United States. The data suggest that Acinetobacter infections are a growing threat affecting a considerable proportion of critically ill patients, especially in Asia and Europe.

Nosocomial pneumonia in the ICU: a prospective cohort study

Ventilator-associated pneumonia (VAP) is the most common intensive care unit (ICU)-acquired infection among patients requiring mechanical ventilation. A prospective surveillance programme of all patients has been implemented at the ICU, Karolinska University Hospital, Sweden since 2001. Within this programme, incidence and risk factors for ICU-acquired pneumonia and associated death over a 2-y period have been studied. Of 329 patients enrolled in the study, 221 required mechanical ventilation. 33 of 221 patients (15%) developed VAP, corresponding to a rate of 29 VAP/1000 ventilator d. Risk factors for VAP were aspiration (hazard ratio 3.79; 95% CI 1.48-9.68), recent surgery (HR 3.58; 95% CI 1.15-11.10) and trauma (HR 3.00; 95% CI 1.03-8.71). 11 patients of 33 (33%) with VAP died within 28 d compared to 46 of 288 (16%) without ICU-acquired pneumonia (odds ratio 2.73; 95% CI 0.97-7.63). We conclude that: 1) incidence of VAP was 15% and the most important risk factor was aspiration; 2) APACHE II score > or = 20 is a stronger predictor for poor outcome than VAP; 3) a minority of patients with APACHE II score > or = 20 develop VAP; and 4) continuous surveillance programmes are feasible and provide valuable data for improvement of quality of care.

Surveillance of antimicrobial use and antimicrobial resistance in German intensive care units (SARI): a summary of the data from 2001 through 2004

Objective:

To report the experience gained over 4 years in working with the German SARI project (Surveillance of Antimicrobial Use and Antimicrobial Resistance in Intensive Care Units), and to compare SARI with data from the Swedish STRAMA and the US AUR surveillance system.

Methods:

Prospective unit and laboratory based surveillance was carried out in 40 German ICUs from 2001 through 2004. WHO 2004 definitions of defined daily doses (DDD) per 1,000 patient days (pd) were used to express antimicrobial consumption (AD). Apart from the proportion of resistant isolates (RP), the incidence density of resistant isolates (RD) was calculated on the basis of the number of resistant isolates per 1,000 pd. To determine the changes over time, the Wilcoxon signed rank test for paired samples was used.

Results:

From 1/2001 through 12/2004, 40 ICUs provided data on 53,399 isolates, a total of 789,569 DDD and 597,592 pd. Total AD ranged from 427 to 2,798, with the median being 1,351. There was no statistically significant change in total antimicrobial use, but a statistically significant decrease was observed in the use of aminoglycosides. RD was highest for MRSA with 4.4 resistant isolates/1,000 pd followed by imipenem resistant Pseudomonas aeruginosa with 1.7 resistant isolates/1,000 pd. The corresponding RPs were 21.5% and 23.2%. Over the 4-year period (2001–2004), significant increases were seen in the RDs of third generation cephalosporin and ciprofloxacin resistant Escherichia coli. In 2004, the mean RD reached 0.28 and 1.41, respectively. In comparison, the RP of selected pathogens was highest in the US ICUs and lowest in Swedish ICUs, with the exception of imipenem resistant P. aeruginosa.

Conclusion:

Antibiotic consumption remained stable over a period of 4 years, (the mean being 1,321 DDD/1,000 pd). The same applied to the situation regarding resistance in Staphylococcus aureus, enterococci and P. aeruginosa. For most pathogens the RP was higher in SARI ICUs than in Swedish ICUs, but lower than in US ICUs.

Low antibiotic resistance rates in Staphylococcus aureus, Escherichia coli and Klebsiella spp but not in Enterobacter spp and Pseudomonas aeruginosa: a prospective observational study in 14 Swedish ICUs over a 5-year period

BACKGROUND

Intensive care units (ICUs) are hot zones for emergence and spread of antibiotic resistance because of frequent invasive procedures, antibiotic usage and transmission of bacteria. We report prospective data on antibiotic use and bacterial resistance from 14 academic and non-academic ICUs, participating in the ICU-STRAMA programme 1999-2003.

METHODS

The quantity of antibiotics delivered to each ICU was calculated as defined daily doses per 1,000 occupied bed days (DDD(1,000)). Specimens for culture were taken on clinical indications and only initial isolates were considered. Species-related breakpoints according to the Swedish Reference Group for Antibiotics were used. Antibiotic resistance was defined as the sum of intermediate and resistant strains.

RESULTS

Mean antibiotic use increased from 1,245 DDD(1,000) in 1999 to 1,510 DDD(1,000) in 2003 (P = 0.11 for trend). Of Staphylococcus aureus, 0-1.8% were methicillin resistant (MRSA). A presumptive extended spectrum beta-lactamase (ESBL) phenotype was found in <2.4% of Escherichia coli, based on cefotaxime susceptibility, except a peak in 2002 (4.6%). Cefotaxime resistance was found in 2.6-4.9% of Klebsiella spp. Rates of resistance among Enterobacter spp. to cefotaxime (20-33%) and among Pseudomonas aeruginosa to imipenem (22-33%) and ciprofloxacin (5-21%) showed no time trend.

CONCLUSION

MRSA and cefotaxime-resistant E. coli and Klebsiella spp strains were few despite high total antibiotic consumption. This may be the result of a slow introduction of resistant strains into the ICUs, and good infection control. The cause of imipenem and ciprofloxacin resistance in P. aeruginosa could reflect the increased consumption of these agents plus spread of resistant clones.

Prescription of antibiotic agents in Swedish intensive care units is empiric and precise

Since the prescription of antibiotics in the hospital setting is often empiric, particularly in the critically ill, and therefore fraught with potential error, we analysed the use of antibiotic agents in Swedish intensive care units (ICUs). We examined indications for antibiotic treatment, agents and dosage prescribed among 393 patients admitted to 23 ICUs at 7 tertiary care centres, 11 secondary hospitals and 5 primary hospitals over a 2-week period in November 2000. Antibiotic consumption was higher among ICU patients in tertiary care centres with a median of 84% (range 58-87%) of patients on antibiotics compared to patients in secondary hospitals (67%, range 35-93%) and in primary hospitals (38%, range 24-80%). Altogether 68% of the patients received antibiotics during the ICU stay compared to 65% on admission. Cefuroxime was the most commonly prescribed antibiotic before and during admission (28% and 24% of prescriptions, respectively). A date for decision to continue or discontinue antibiotic therapy was set in 21% (6/29) of patients receiving prophylaxis, in 8% (16/205) receiving empirical treatment and in 3% (3/88) when culture-based therapy was given. No correlation between antibiotic prescription and laboratory parameters such as CRP levels, leukocyte and thrombocyte counts, was found. The treatment was empirical in 64% and prophylactic in 9% of cases. Microbiological data guided prescription more often in severe sepsis (median 50%, range 40-60% of prescriptions) than in other specified forms of infection (median 32%, range 21-50%). The empirically chosen antibiotic was found to be active in vitro against the pathogens found in 55 of 58 patients (95%) with a positive blood culture. This study showed that a high proportion of ICU patients receive antimicrobial agents and, as expected, empirical-based therapy is more common than culture-based therapy. Antibiotics given were usually active in vitro against the pathogen found in blood cultures. We ascribe this to a relatively modest antibiotic resistance problem in Swedish hospitals.

Transmission of Staphylococcus aureus from maternity unit staff members to newborns disclosed through spa typing

BACKGROUND

We observed previously that newborn infants are colonized with Staphylococcus aureus, even if their mothers do not carry S aureus. This observation indicated a cross colonization, and, thus, a risk for nosocomial infection, although the infants are roomed in with their mothers.

METHODS

The S aureus colonization of infants, their parents, and staff members was measured at 3 maternity units. Possible transmission routes were determined using spa typing of S aureus isolates.

RESULTS

Infants had the highest S aureus carriage (45%) compared with fathers (39%), mothers (27%), and staff members (27%). In 13 out of 44 colonized infants, transmission from staff members was indicated. This transmission was more frequent than was transmission from their own parents (11 cases), and occurred even in cases when parents were colonized with S aureus of other spa types.

CONCLUSIONS

We confirm a high level of transmission of S aureus from staff members to infants, indicating a risk for patient safety, which necessitates continuing work with implementing scientific evidence for infection control. The spa typing is a rapid and valuable epidemiological tool, and it can be used in improving hospital hygiene control programs.

Central venous catheter infections at a county hospital in Sweden: a prospective analysis of colonization, incidence of infection and risk factors

BACKGROUND

Catheter-related infection (CRI) is one of the most serious complications of the use of central venous catheters (CVCs), with an incidence of 2-30/1000 days in different studies. No major prospective study has evaluated the rate of CRI in Scandinavia. Since 1999, we have had a thorough programme for the insertion and care of all CVCs used at our hospital and its outpatient clinics. The purpose of this survey was to study the incidence of catheter tip colonization and CRI and their risk factors, and to compare these data with previous non-Scandinavian studies.

METHODS

We studied prospectively 605 CVCs in 456 patients in relation to insertion data, patient and catheter characteristics, catheterization time and microbiological cultures. Risk factors were analysed by multivariate analysis.

RESULTS

Four hundred and ninety-five (82%) of all CVCs were assessed completely. The total catheterization time was 9010 days. The incidence of positive tip culture was 7.66/1000 days, and the predominant microorganism was coagulase-negative staphylococci. The incidence of CRI was 1.55/1000 days, and the only significant risk factor was the duration of catheterization with a relative risk of 1.009 per day [95% confidence interval (CI), 1.003-1.015]. Of the 14 cases with CRI, six were associated with candida species, and five of these were diagnosed in the intensive care unit.

CONCLUSION

In comparison with non-Scandinavian studies, our practice of strict basic hygiene routines for CVC insertion and care is associated with a low incidence of CRI. However, there was a high proportion of candida species amongst these infections. The only risk factor for CRI was the duration of catheterization.

Host defense peptides in burns

Overuse of antibiotics and failure to apply basic infection control policies and procedures have contributed to the increasing multi-drug resistance of many nosocomial pathogens. The alarming increase of multi-drug-resistant bacteria (e.g. Pseudomonas aeruginosa, methicilin-resistant Staphylococci, vancomycin-resistant Enterococci) causes infected wounds associated with high mortality and morbidity in burned patients and focuses attention on the need for better treatment and prevention of wound infections. The review points out and discusses some emerging alternatives to antibiotics used in clinical practice, with special emphasis on the role of the innate immune response and potential application of human host defense peptides in thermal injury.

Epidemiology and control of antibiotic resistance in the intensive care unit

PURPOSE OF REVIEW

Resistance to antibiotics is very high in the intensive care units of many countries, although there are several exceptions. Some infections are becoming extremely difficult to treat. The risk of cross-transmission of those strains is very high. This review focuses on recent data (2003 to the present) that may help understanding and dealing with this serious public health problem.

RECENT FINDINGS

Intensive care units can be considered as 'factories' for creating, disseminating and amplifying resistance to antibiotics, for many reasons: importation of resistant microorganisms at admission, selection of resistant strains with an extensive use of broad-spectrum antibiotics, cross-transmission of resistant strains via the hands or the environment. Some national programs can be considered as failures, as in the UK and the USA. Other countries have been able to maintain a low level of resistance (Scandinavian countries, Netherlands, Switzerland, Germany, Canada). There is clearly an 'inoculum effect' above which preventive measures become poorly efficient. Several preventive measures have been proposed including preventive isolation, systematic screening at admission, local, national or international antibiotic guidelines, antibiotic prescriptions advice by infectious-disease teams, antibiotic prevention with selective digestive decontamination, antibiotic strategies such as 'cycling', or rather, for some authors, the use of an 'à la carte' antibiotic strategy which could be considered as a 'patient-to-patient antibiotic rotation'.

SUMMARY

There is obviously an international concern regarding the level of resistance to antibiotics in the intensive-care-unit setting. A strong program including prevention of cross-transmission and better usage of antibiotics seems to be needed in order to be successful. We do not know if this kind of program will enable countries with a very high endemic level of resistance to decrease the level in future years.