Cefepime-resistant Pseudomonas aeruginosa

Antimicrobial Resistance Pattern of Pseudomonas aeruginosa: An 11-Year Experience in a Tertiary Care Hospital in Makkah, Saudi Arabia

Purpose

Pseudomonas aeruginosa (P. aeruginosa) is a common causative pathogen in healthcare settings and displays increasing levels of resistance to common antimicrobial drugs. Its capacity to resist has been reported in multiple locations across the world. This study evaluates current levels of antibiotic resistance and seeks to understand antibiotic resistance patterns in the context of the clinical isolates of P. aeruginosa.

Methods

All clinical isolates were cultured at 37 °C for 24 h in different media: blood sheep agar, McConkey agar, and cystine-lactose-electrolyte-deficient agar (CLED), bacterial identification and antibiotic susceptibility patterns were determined using the Vitek-2 (bioMérieux) automated system.

Results

In total, there were 61,029 patient specimens, of which 5534 were identified as non-duplicated P. aeruginosa clinical isolates, most being from males aged over 60 years. The research findings revealed that the maximum antibiotic resistance associated with P. aeruginosa isolates was found in colistin (97%), which was followed by piperacillin/tazobactam (75.8%). The maximum resistance rates in P. aeruginosa isolates were found in relation to cefepime (42.7%,) which was followed by ciprofloxacin (34.3%).

Conclusion

The antibiotic resistance rate during the first six years of the research period was notably higher than in the last years, due to the application of infection control protocols and strict policies to control antibiotic prescriptions in all Saudi hospitals.

Pseudomonas aeruginosa in tracheal aspirate: Colonization, infection, and recurrence

INTRODUCTION

Pseudomonas aeruginosa respiratory infections are challenging, and the risk of recurrence is a frequent problem. The aim of this study was to investigate the risk factors associated with the presence of P. aeruginosa, and the risk factors related to the recurrence and death of lower airway infections in inpatients in a Brazilian hospital.

METHODS

Retrospective cohort with inpatients that had a sample of airways culture (tracheal aspirate or bronchoalveolar lavage) with the detection of P. aeruginosa. The patients with clinical criteria of infection were classified as ventilator-associated, hospital-acquired, or community-acquired pneumonia. P. aeruginosa in respiratory samples without symptoms was considered colonization. The antimicrobial treatment adequacy and the clinical data were evaluated. Outcome variables included mortality and recurrence.

RESULTS

One hundred and fifty-four patients were included in the study, most of them were men, and the majority (102) were considered infected. The average length of stay was superior to 30 days. Previous pulmonary disease was associated with the occurrence of colonization. Aminoglycosides were the most active drug according to susceptibility tests and were successfully used as monotherapy. Septic shock was a risk factor for death in the infected patients. The use of adequate antimicrobial therapy was associated with major survival, independent of the infection classification.

CONCLUSION

It is possible to evaluate clinical data associated with recurrence and mortality in patients with different lung infections by P. aeruginosa. Aminoglycoside monotherapy is safe and effective in P. aeruginosa respiratory infections.

Distribution of serotypes and antibiotic resistance of invasive Pseudomonas aeruginosa in a multi-country collection

Background

Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of acute and chronic infections and is frequently associated with healthcare-associated infections. Because of its ability to rapidly acquire resistance to antibiotics, P. aeruginosa infections are difficult to treat. Alternative strategies, such as a vaccine, are needed to prevent infections. We collected a total of 413 P. aeruginosa isolates from the blood and cerebrospinal fluid of patients from 10 countries located on 4 continents during 2005–2017 and characterized these isolates to inform vaccine development efforts. We determined the diversity and distribution of O antigen and flagellin types and antibiotic susceptibility of the invasive P. aeruginosa. We used an antibody-based agglutination assay and PCR for O antigen typing and PCR for flagellin typing. We determined antibiotic susceptibility using the Kirby-Bauer disk diffusion method.

Results

Of the 413 isolates, 314 (95%) were typed by an antibody-based agglutination assay or PCR (n = 99). Among the 20 serotypes of P. aeruginosa, the most common serotypes were O1, O2, O3, O4, O5, O6, O8, O9, O10 and O11; a vaccine that targets these 10 serotypes would confer protection against more than 80% of invasive P. aeruginosa infections. The most common flagellin type among 386 isolates was FlaB (41%). Resistance to aztreonam (56%) was most common, followed by levofloxacin (42%). We also found that 22% of strains were non-susceptible to meropenem and piperacillin-tazobactam. Ninety-nine (27%) of our collected isolates were resistant to multiple antibiotics. Isolates with FlaA2 flagellin were more commonly multidrug resistant (p = 0.04).

Conclusions

Vaccines targeting common O antigens and two flagellin antigens, FlaB and FlaA2, would offer an excellent strategy to prevent P. aeruginosa invasive infections.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02427-4.

Cephalosporins Interfere With Quorum Sensing and Improve the Ability of Caenorhabditis elegans to Survive Pseudomonas aeruginosa Infection

Pseudomonas aeruginosa utilizes the quorum sensing (QS) system to strategically coordinate virulence and biofilm formation. Targeting QS pathways may be a potential anti-infective approach to treat P. aeruginosa infections. In the present study, we define cephalosporins' anti-QS activity using Chromobacterium violaceum CV026 for screening and QS-regulated mutants of P. aeruginosa for validation. We quantified the effects of three cephalosporins, cefepime, ceftazidime, and ceftriaxone, on (1) pyocyanin production using spectrophotometric assay, (2) bacterial motility using agar plate assay, and (3) biofilm formation using scanning electron microscopy. We also studied isogenic QS mutant strains of PAO1 (ΔlasR,ΔrhlR,ΔpqsA, and ΔpqsR) to compare and distinguish QS-mediated effects on the motility phenotypes and bacterial growth with and without sub-MIC concentrations of antibiotics. Results showed that cephalosporins have anti-QS activity and reduce bacterial motility, pyocyanin production, and biofilm formation for CV026 and PAO1. Also, sub-MICs of cefepime increased aminoglycosides' antimicrobial activity against P. aeruginosa PAO1, suggesting the advantage of combined anti-QS and antibacterial treatment. To correlate experimentally observed anti-QS effects with the interactions between cephalosporins and QS receptors, we performed molecular docking with ligand binding sites of quorum sensing receptors using Autodock Vina. Molecular docking predicted cephalosporins' binding affinities to the ligand-binding pocket of QS receptors (CviR, LasR, and PqsR). To validate our results using an infection model, we quantified the survival rate of Caenorhabditis elegans following P. aeruginosa PAO1 challenge at concentrations less than the minimum inhibitory concentration (MIC) of antibiotics. C. elegans infected with PAO1 without antibiotics showed 0% survivability after 72 h. In contrast, PAO1-infected C. elegans showed 65 ± 5%, 58 ± 4%, and 49 ± 8% survivability after treatment with cefepime, ceftazidime, and ceftriaxone, respectively. We determined the survival rates of C. elegans infected by QS mutant strains ΔlasR (32 ± 11%), ΔrhlR (27 ± 8%), ΔpqsA (27 ± 10%), and ΔpqsR (37 ± 6%), which suggest essential role of QS system in virulence. In summary, cephalosporins at sub-MIC concentrations show anti-QS activity and enhance the antibacterial efficacy of aminoglycosides, a different class of antibiotics. Thus, cephalosporins at sub-MIC concentrations in combination with other antibiotics are potential candidates for developing therapies to combat infections caused by P. aeruginosa.

A Meta-Analysis of the Prevalence of Class 1 Integron and Correlation with Antibiotic Resistance in Pseudomonas aeruginosa Recovered from Iranian Burn Patients

The role of integrons has been highlighted in antibiotic resistance among Pseudomonas aeruginosa isolates. Therefore, we here reviewed the prevalence of class 1 integrons and their correlations with antibiotic resistance of P. aeruginosa isolated from Iranian burn patients. This review was conducted according to the guidelines of Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA). Cross-sectional and cohort studies published from January 1, 2000 until December 31, 2018 were enrolled. Meta-analysis was performed by Comprehensive Meta-Analysis (CMA) software using the random effects model, Cochran's Q, and I2 tests. Publication bias was estimated by Funnel plot and Egger's linear regression test. Nine out of 819 studies met the eligibility criteria. The overall combined prevalence of class 1 integrons in P. aeruginosa isolates was 69% (95% confidence interval [CI]: 50.5-83%). The highest combined resistance was reported against Cloxacillin (87.7%), followed by Carbenicillin (79.1%) and Ceftriaxone (77.3%). The combined prevalence of multidrug-resistant (MDR) isolates was 79.3% (95% CI: 31.1-97%). Also, a significant correlation was noted between the presence of class 1 integrons and antibiotic resistance in 55.5% of the included studies (P < .05). The results showed high prevalence of class 1 integrons, antibiotic resistance, and MDR strains in P. aeruginosa isolated from Iranian burn patients. Also, most of the included studies showed a significant correlation between the presence of class 1 integrons and antibiotic resistance.

Microbial Resistance Movements: An Overview of Global Public Health Threats Posed by Antimicrobial Resistance, and How Best to Counter

Antibiotics changed medical practice by significantly decreasing the morbidity and mortality associated with bacterial infection. However, infectious diseases remain the leading cause of death in the world. There is global concern about the rise in antimicrobial resistance (AMR), which affects both developed and developing countries. AMR is a public health challenge with extensive health, economic, and societal implications. This paper sets AMR in context, starting with the history of antibiotics, including the discovery of penicillin and the golden era of antibiotics, before exploring the problems and challenges we now face due to AMR. Among the factors discussed is the low level of development of new antimicrobials and the irrational prescribing of antibiotics in developed and developing countries. A fundamental problem is the knowledge, attitude, and practice (KAP) regarding antibiotics among medical practitioners, and we explore this aspect in some depth, including a discussion on the KAP among medical students. We conclude with suggestions on how to address this public health threat, including recommendations on training medical students about antibiotics, and strategies to overcome the problems of irrational antibiotic prescribing and AMR.

Risk factors for hospitalized patients with resistant or multidrug-resistant Pseudomonas aeruginosa infections: a systematic review and meta-analysis

Background

Identifying risk factors predicting acquisition of resistant Pseudomonas aeruginosa will aid surveillance and diagnostic initiatives and can be crucial in early and appropriate antibiotic therapy. We conducted a systematic review examining risk factors of acquisition of resistant P. aeruginosa among hospitalized patients.

Methods

MEDLINE®, EMBASE®, and Cochrane Central were searched between 2000 and 2016 for studies examining independent risk factors associated with acquisition of resistant P. aeruginosa, among hospitalized patients. Random effects model meta-analysis was conducted when at least three or more studies were sufficiently similar.

Results

Of the 54 eligible articles, 28 publications (31studies) examined multi-drug resistant (MDR) or extensively drug resistant (XDR) P. aeruginosa and 26 publications (29 studies) examined resistant P. aeruginosa. The acquisition of MDR P. aeruginosa, as compared with non-MDR P. aeruginosa, was significantly associated with intensive care unit (ICU) admission (3 studies: summary adjusted odds ratio [OR] 2.2) or use of quinolones (4 studies: summary adjusted OR 3.59). Acquisition of MDR or XDR compared with susceptible P. aeruginosa was significantly associated with prior hospital stay (4 studies: summary adjusted OR 1.90), use of quinolones (3 studies: summary adjusted OR 4.34), or use of carbapenems (3 studies: summary adjusted OR 13.68). The acquisition of MDR P. aeruginosa compared with non-P. aeruginosa was significantly associated with prior use of cephalosporins (3 studies: summary adjusted OR 3.96), quinolones (4 studies: summary adjusted OR 2.96), carbapenems (6 studies: summary adjusted OR 2.61), and prior hospital stay (4 studies: summary adjusted OR 1.74). The acquisition of carbapenem-resistant P. aeruginosa compared with susceptible P. aeruginosa, was statistically significantly associated with prior use of piperacillin-tazobactam (3 studies: summary adjusted OR 2.64), vancomycin (3 studies: summary adjusted OR 1.76), and carbapenems (7 studies: summary adjusted OR 4.36).

Conclusions

Prior use of antibiotics and prior hospital or ICU stay was the most significant risk factors for acquisition of resistant P. aeruginosa. These findings provide guidance in identifying patients that may be at an elevated risk for a resistant infection and emphasize the importance of antimicrobial stewardship and infection control in hospitals.

Penicillin-Binding Protein 3 Is Essential for Growth of Pseudomonas aeruginosa

Penicillin-binding proteins (PBPs) function as transpeptidases, carboxypeptidases, or endopeptidases during peptidoglycan synthesis in bacteria. As the well-known drug targets for β-lactam antibiotics, the physiological functions of PBPs and whether they are essential for growth are of significant interest. The pathogen Pseudomonas aeruginosa poses a particular risk to immunocompromised and cystic fibrosis patients, and infections caused by this pathogen are difficult to treat due to antibiotic resistance. To identify potential drug targets among the PBPs in P. aeruginosa, we performed gene knockouts of all the high-molecular-mass (HMM) PBPs and determined the impacts on cell growth and morphology, susceptibility to β-lactams, peptidoglycan structure, virulence, and pathogenicity. Disruptions of the transpeptidase domains of most HMM PBPs, including double disruptions, had only minimal effects on cell growth. The exception was PBP3, where cell growth occurred only when the protein was conditionally expressed on an integrated plasmid. Conditional deletion of PBP3 also caused a defect in cell division and increased susceptibility to β-lactams. Knockout of PBP1a led to impaired motility, and this observation, together with its localization at the cell poles, suggests its involvement in flagellar function. Overall, these findings reveal that PBP3 represents the most promising target for drug discovery against P. aeruginosa, whereas other HMM PBPs have less potential.

Analysis of the third- and fourth-generation cephalosporin use for the treatment of infections caused by Gram-negative bacteria in hospital settings

OBJECTIVE

The aims of our study were to assess the prevalence and distribution of Gram-negative (G-) bacteria in hospital isolates, their sensitivity to the third- and fourth-generation cephalosporins (c3 and c4), therapeutic use of c3 and c4 in the treatment of G- infections and drug utilisation data.

RESEARCH DESIGN AND METHODS

This cross-sectional study collected medical records data from the General Hospital "Gornji Milanovac" (GM) and the University Medical Center "Bezanijska kosa" (BK). The time frame of the study was 12 months. Microbiological and clinical parameters, and c3/c4 drug utilisation were analysed.

RESULTS

Escherichia coli were the most predominant pathogen in GM and BK, accounting for 43% and 28% of all G- isolates, respectively (GM), 884 G- isolates obtained from 606 patients; BK, 1766 isolates obtained from 1045 patients). Nearly half of the isolates (55% and 43%) were obtained from urine samples collected from the surgical ward (GM), and the internal medicine wards and intensive care unit (BK). On average, the resistance rate of G- strains against c3 and c4 reached 40% and 70%, respectively (lowest in E. coli, 8%-25%; highest in Acinetobacer baumannii, 67%-100%). Resistance rate of Pseudomonas spp. to cefepime and ceftazidime was low/moderate (0%-30% and 19%-47%). In BK, the adult patients were older than in GM (75 vs 66 years), with longer hospital stay (19 vs 10 days) and bacteria were isolated later during hospitalisation (10 vs 2 days). C3 and c4 were more often used in empirical therapy (83% vs 64%) in BK. Ceftazidime and cefepime were used more often in BK than in GM (2.036 vs 69 DDD/y and 586 vs. 126 DDD/y, respectively).

CONCLUSION

The use of c3 and c4 in the treatment of G- infections in both hospitals should be re-evaluated in accordance with current guidelines and local resistance.

SHV-129: A Gateway to Global Suppressors in the SHV β-Lactamase Family?

Enzymes are continually evolving in response to environmental pressures. In order to increase enzyme fitness, amino acid substitutions can occur leading to a changing function or an increased stability. These evolutionary drivers determine the activity of an enzyme and its success in future generations in response to changing conditions such as environmental stressors or to improve physiological function allowing continual persistence of the enzyme. With recent warning reports on antibiotic resistance and multidrug resistant bacterial infections, understanding the evolution of β-lactamase enzymes, which are a large contributor to antibiotic resistance, is increasingly important. Here, we investigated a variant of the SHV β-lactamase identified from a clinical isolate of Escherichia coli in 2011 (SHV-129, G238S-E240K-R275L-N276D) to identify the first instance of a global suppressor substitution in the SHV β-lactamase family. We have used this enzyme to show that several evolutionary principles are conserved in different class A β-lactamases, such as active site mutations reducing stability and requiring compensating suppressor substitutions in order to ensure evolutionary persistence of a given β-lactamase. However, the pathway taken by a given β-lactamase in order to reach its evolutionary peak under a given set of conditions is likely different. We also provide further evidence for a conserved stabilizing substitution among class A β-lactamases, the back to consensus M182T substitution. In addition to expanding the spectrum of β-lactamase activity to include the hydrolysis of cefepime, the amino acid substitutions found in SHV-129 provide the enzyme with an excess of stability, which expands the evolutionary landscape of this enzyme and may result in further evolution to potentially include resistance to carbapenems or β-lactamase inhibitors.

Acquisition of Pseudomonas aeruginosa and its resistance phenotypes in critically ill medical patients: role of colonization pressure and antibiotic exposure

INTRODUCTION

The objective of this work was to investigate the risk factors for the acquisition of Pseudomonas aeruginosa and its resistance phenotypes in critically ill patients, taking into account colonization pressure.

METHODS

We conducted a prospective cohort study in an 8-bed medical intensive care unit during a 35-month period. Nasopharyngeal and rectal swabs and respiratory secretions were obtained within 48 hours of admission and thrice weekly thereafter. During the study, a policy of consecutive mixing and cycling periods of three classes of antipseudomonal antibiotics was followed in the unit.

RESULTS

Of 850 patients admitted for ≥ 3 days, 751 (88.3%) received an antibiotic, 562 of which (66.1%) were antipseudomonal antibiotics. A total of 68 patients (8%) carried P. aeruginosa upon admission, and among the remaining 782, 104 (13%) acquired at least one strain of P. aeruginosa during their stay. Multivariate analysis selected shock (odds ratio (OR) = 2.1; 95% confidence interval (CI), 1.2 to 3.7), intubation (OR = 3.6; 95% CI, 1.7 to 7.5), enteral nutrition (OR = 3.6; 95% CI, 1.8 to 7.6), parenteral nutrition (OR = 3.9; 95% CI, 1.6 to 9.6), tracheostomy (OR = 4.4; 95% CI, 2.3 to 8.3) and colonization pressure >0.43 (OR = 4; 95% CI, 1.2 to 5) as independently associated with the acquisition of P. aeruginosa, whereas exposure to fluoroquinolones for >3 days (OR = 0.4; 95% CI, 0.2 to 0.8) was protective. In the whole series, prior exposure to carbapenems was independently associated with carbapenem resistance, and prior amikacin use predicted piperacillin-tazobactam, fluoroquinolone and multiple-drug resistance.

CONCLUSIONS

In critical care settings with a high rate of antibiotic use, colonization pressure and non-antibiotic exposures may be the crucial factors for P. aeruginosa acquisition, whereas fluoroquinolones may actually decrease its likelihood. For the acquisition of strains resistant to piperacillin-tazobactam, fluoroquinolones and multiple drugs, exposure to amikacin may be more relevant than previously recognized.

Non-fermentative gram-negative bacteria in hospital tap water and water used for haemodialysis and bronchoscope flushing: prevalence and distribution of antibiotic resistant strains

This study provides a detailed description of the distribution of non-fermentative gram-negative bacteria (NFGNB) collected in water sources (tap water and water used for haemodialysis and bronchoscope flushing) from different wards of a tertiary care hospital. The aim is to identify risk practices for patients or to alert clinicians to the possible contamination of environment and medical devices. The resistance profile of NFGNB environmental isolates has shown that more than half (55.56%) of the strains isolated were resistant to one or more antibiotics tested in different antimicrobial categories. In particular, 38.89% of these strains were multidrug resistant (MDR) and 16.67% were extensively drug resistant (XDR). The most prevalent bacterial species recovered in water samples were Pseudomonas aeruginosa, Pseudomonas fluorescens, Ralstonia pickettii and Stenotrophomonas maltophilia. Analysis of antibiotic resistance rates has shown remarkable differences between Pseudomonadaceae (P. aeruginosa and P. fluorescens) and emerging pathogens, such as S. maltophilia and R. pickettii. Multidrug resistance can be relatively common among nosocomial isolates of P. aeruginosa, which represent the large majority of clinical isolates; moreover, our findings highlight that the emergent antibiotic resistant opportunistic pathogens, such as R. pickettii and S. maltophilia, isolated from hospital environments could be potentially more dangerous than other more known waterborne pathogens, if not subjected to surveillance to direct the decontamination procedures.

Clinical and economic consequences of hospital-acquired resistant and multidrug-resistant Pseudomonas aeruginosa infections: a systematic review and meta-analysis

Background

Increasing rates of resistant and multidrug-resistant (MDR) P. aeruginosa in hospitalized patients constitute a major public health threat. We present a systematic review of the clinical and economic impact of this resistant pathogen.

Methods

Studies indexed in MEDLINE and Cochrane databases between January 2000-February 2013, and reported all-cause mortality, length of stay, hospital costs, readmission, or recurrence in at least 20 hospitalized patients with laboratory confirmed resistant P. aeruginosa infection were included. We accepted individual study definitions of MDR, and assessed study methodological quality.

Results

The most common definition of MDR was resistance to more than one agent in three or more categories of antibiotics. Twenty-three studies (7,881 patients with susceptible P. aeruginosa, 1,653 with resistant P. aeruginosa, 559 with MDR P. aeruginosa, 387 non-infected patients without P. aeruginosa) were analyzed. A random effects model meta-analysis was feasible for the endpoint of all-cause in-hospital mortality. All-cause mortality was 34% (95% confidence interval (CI) 27% – 41%) in patients with any resistant P. aeruginosa compared to 22% (95% CI 14% – 29%) with susceptible P. aeruginosa. The meta-analysis demonstrated a > 2-fold increased risk of mortality with MDR P. aeruginosa (relative risk (RR) 2.34, 95% CI 1.53 – 3.57) and a 24% increased risk with resistant P. aeruginosa (RR 1.24, 95% CI 1.11 – 1.38), compared to susceptible P. aeruginosa. An adjusted meta-analysis of data from seven studies demonstrated a statistically non-significant increased risk of mortality in patients with any resistant P. aeruginosa (adjusted RR 1.24, 95% CI 0.98 – 1.57). All three studies that reported infection-related mortality found a statistically significantly increased risk in patients with MDR P. aeruginosa compared to those with susceptible P. aeruginosa. Across studies, hospital length of stay (LOS) was higher in patients with resistant and MDR P. aeruginosa infections, compared to susceptible P. aeruginosa and control patients. Limitations included heterogeneity in MDR definition, restriction to nosocomial infections, and potential confounding in analyses.

Conclusions

Hospitalized patients with resistant and MDR P. aeruginosa infections appear to have increased all-cause mortality and LOS. The negative clinical and economic impact of these pathogens warrants in-depth evaluation of optimal infection prevention and stewardship strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/2047-2994-3-32) contains supplementary material, which is available to authorized users.

Clinical characteristics and risk factors for mortality in cefepime-resistant Pseudomonas aeruginosa bacteremia

BACKGROUND

To identify the clinical characteristics and risk factors for mortality of patients with cefepime-resistant Pseudomonas aeruginosa (FRPa) bacteremia.

METHODS

This retrospective study analyzed adult patients with FRPa bacteremia hospitalized between January 2006 and December 2011.

RESULTS

Seventy eight patients (46 male, 32 female; mean age: 72.2 ± 14.1 years) were included. Of them, 46 (59.0%) had ventilator use and 45 (57.7%) had intensive care unit stay. All the bacteremia episodes were health-care associated or hospital acquired, and 55.1% of FRPa blood isolates were multidrug resistant. The sources of bacteremia were identified in 42 patients (53.8%), with pneumonia being the most common one (28/42; 66.7%). The mean interval between admission and the sample date of the first FRPa-positive blood culture was 45.8 ± 52.6 days. The mean Pittsburgh bacteremia score was 5.0 ± 3.4. The 15-day and 30-day mortality rates were 50.0% and 65.4%, respectively. Patients (41; 52.6%) on appropriate antibiotic therapy within 72 hours of the first FRPa-positive blood culture had a higher 30-day survival rate than those without (48.8% vs. 18.9%, p = 0.011 by log-rank test). Multivariate analyses revealed that a higher Pittsburgh bacteremia score was an independent risk factor for either 15-day (p = 0.002) or 30-day mortality (p = 0.010), and appropriate antibiotic therapy within 72 hours was an independent protecting factor for either 15-day (p = 0.049) or 30-day mortality (p = 0.017).

CONCLUSION

FRPa bacteremia had a high mortality rate. The disease severity and appropriate antimicrobial therapy within 72 hours of positive blood culture were related to the patients' outcome.

Epidemiological interpretation of studies examining the effect of antibiotic usage on resistance

Bacterial resistance to antibiotics is a growing clinical problem and public health threat. Antibiotic use is a known risk factor for the emergence of antibiotic resistance, but demonstrating the causal link between antibiotic use and resistance is challenging. This review describes different study designs for assessing the association between antibiotic use and resistance and discusses strengths and limitations of each. Approaches to measuring antibiotic use and antibiotic resistance are presented. Important methodological issues such as confounding, establishing temporality, and control group selection are examined.

Changes in the incidence of multiresistant pathogens and its consequences in intensive care unit

Incidence of nosocomial infections and antibiotics resistance in intensive care units is increasing worldwide. Blood-stream infections of Gram-negative non-fermentive bacteria are associated with higher mortality. Aim and methods: The aim of this study was to compare the antibiotic sensitivity of nosocomial blood-stream infections between years 2008–2010. Results: There was no difference in the sensitivity of methycillin-resistant Staphylococcus aureus and extended-spectrum beta lactamase producing Klebsiella spp. and Escherichia coli infections between the two years examined. Antibiotic resistance of Acinetobacter baumannii and Pseudomonas infections showed a marked increase in 2010 when compared to that found in 2008: there was no multiresistant Acinetobacter infection in samples obtained in 2008, but all these infections were found to be sensitive only to colistin in samples investigated in 2010. Sensitivity of Pseudomonas infections to carbapenems and piperacillin/tazobactam decreased significantly during this time. In addition, the authors found that the mortality of multiresistant Gram-negative blood-stream infections was higher compared to that caused by non-multiresistant bacteria. Conclusions: These results emphasize the importance of infection control, adequate dosing and timing of antibiotics, and an appropriate number of nurses in intensive care unit. Orv. Hetil., 2011, 152, 1486–1491.