Bacterial Susceptibility Profiles Research Articles

Prevalence and antimicrobial susceptibility profile of uropathogens in dogs and cats with signs of urinary tract infection.

To determine the prevalence of uropathogens in dogs and cats with signs of urinary tract infection and to characterise their antimicrobial susceptibility. Urine samples from canine and feline patients with clinical signs of urinary tract infection were collected between September 2015 and December 2019 in Santiago, Chile. Bacterial identification and bacterial susceptibility profile was performed through biochemical and antimicrobial susceptibility tests. Four hundred sixty-six samples from dogs (37.7%) and 152 from cats (26.1%) showed bacterial growth. Positive samples were mainly from females (dogs: 52.8%; cats: 48.0%), with the highest infection rates in senior dogs (57.7%) and adult cats (45.4%). A single organism caused the infection in 78.2% of the cases, whereas the remaining 21.8% corresponded to a mixed infection. The most prevalent isolated pathogen in dogs and cats was Escherichia coli (42.6% and 49.7%, respectively). Staphylococcus spp. (15.6% and 14.6%), Enterococcus spp. (8.6% and 15.2%) and Proteus spp. (9.7% and 6.4%) were also commonly isolated. A total of 52.4% of Escherichia coli isolates were resistant to amoxicillin, 44.3% to amoxicillin/clavulanic acid, 40.0% to cephradine and 25.3% to ciprofloxacin. Regarding the other three uropathogens commonly isolated in this study, all of them showed a percentage of resistance to the antimicrobials analysed. In addition, 24.6% of multidrug resistance was detected in the E. coli isolates. Penicillin, cephalosporins and fluoroquinolones showed the lowest susceptibility levels. The observed high rates of resistance to commonly prescribed antimicrobials raise concerns for public health.

The volatile organic compounds detection in MDR Gram-negatives antimicrobial susceptibility testing: Results from a four-month laboratory experience

Systemic bacterial infections represent a significant clinical challenge due to the increasing resistance rate towards antimicrobials. An essential key to controlling antimicrobial resistance spread is to administer targeted therapy after a precise minimum inhibitory concentration reporting. Among the available fast technologies for antimicrobial susceptibility testing (AST), the VITEKⓇ REVEAL™ (Biomerieux, Florence, Italy) proposes volatile organic compounds (VOC) colourimetric arrays to discriminate between susceptible and resistant Gram-negative isolates directly from positive blood cultures. We evaluated this methodology during a four-month laboratory experience on 40 positive blood culture samples, reporting a comparison to standard culture-based methods. The protocol revealed an essential agreement of 100 % between the conventional and the experimental procedures, while the categorical agreement resulted in 97.5 % due to one very major error (VME) for meropenem/vaborbactam in K. pneumoniae. Although further studies will be necessary to investigate its performance on rare microorganisms, the VITEKⓇ REVEAL™ demonstrated an optimal sensitivity in defining MIC values for multi-drug resistant (MDR) microorganisms. These results encourage the application of the method in all high-risk epidemiological areas, confirming the effectiveness of VOC detection in monitoring bacterial susceptibility profiles.

Indoor air microbial load, antibiotic susceptibility profiles of bacteria, and associated factors in different wards of Arba Minch General Hospital, southern Ethiopia.

The levels of indoor air microbial load in hospitals are very crucial to the health of patients and health care workers and are to be regularly monitored and maintained at an acceptable level. However, this problem remains overlooked, particularly in developing countries including Ethiopia. A hospital-based cross-sectional study is designed to determine the indoor air microbial load (settle plate technique), microbial isolates (standard microbiological techniques), bacterial susceptibility profiles (Kirby-Bauer disk diffusion technique), and associated factors, in different wards of the title Hospital, southern Ethiopia. An observational checklist was used to collect relevant information related to the associated factors; descriptive and inferential statistics were applied using Statistical Package for Social Sciences (SPSS); p-values ≤ 0.05 in the multivariable analysis were considered statistically significant. The total average bacterial and fungal load of the selected wards was 1914±1081.4 Colony Forming Units (CFU)/m3 (95% CI: 1718.5–2109.48 CFU/m3) and 1533.7±858.8 CFU/m3 (95% CI: 1378.5-1688CFU/m3) respectively. The highest mean bacterial (1914±1081.4 CFU/m3) and fungal (1533.7±858.8 CFU/m3) loads were found in the male surgical and female medical wards respectively. A total of 229 bacterial and 139 fungal isolates were obtained; Gram-positive bacteria were the predominant type, 130 (56.7%), particularly the isolates of Staphylococcus aureus, 46 (20.1%). The predominant fungal isolates were Aspergillus sp., 53(38%). Percentages of multidrug-resistant (MDR), extended-spectrum beta-lactamase (ESBL), and carbapenemase producers respectively were 48.5, 26.5, and 25%. High room crowd index [p = 0.003; Adjusted Odds Ratio (AOR) 12.5 (Confidence Interval (CI) 95%: 2.42–65)], presence of damp/wet materials [p = 0.025; AOR 7 (CI 95%: 1.3–37.4)], intense room traffic [p = 0.004; AOR 9.6 (CI 95%: 1.2–79.3)], inappropriate storage of food and drugs [p = 0.008; AOR 7.5 (CI 95%: 1.7–32)], and unclean environment [p = 0.03; AOR 5.8 (CI 95%: 1.2–28)] showed statistical significance concerning the indoor air microbial loads; most of the wards in Arba Minch General Hospital (AMGH) stand high and not in an acceptable level as per the WHO and the European Commission standards on indoor air microbial load. Periodic air surveillance and infection prevention control programs are required to reduce the transmission of these microbes to inpatients, visitors, and health care workers.

The first report of the blaIMP-10 gene and complete sequence of the IMP-10-encoding plasmid p12NE515 from Pseudomonas aeruginosa in China

ObjectiveTo investigate a detailed genomic characterization of the blaIMP-10-carrying plasmid p12NE515 from a Pseudomonas aeruginosa isolate in China. MethodsPlasmid p12NE515 was subjected to whole-genome sequencing and the complete sequence was compared with related plasmid sequences. Transferability of plasmid, carbapenemase activity and bacterial susceptibility profiles were determined to assess p12NE515-mediated resistance phenotypes. ResultsP. aeruginosa 12NE515 was identified as a less common sequence type of ST1976. p12NE515 harboring blaIMP-10 possessed a backbone identical to plasmid p60512-IMP (carrying blaIMP-1), but the accessory resistance regions differed. Only one accessory module, Tn7339, was carried in p12NE515, and this transposon was an insertion sequence-mediated transposition unit generated by the insertion of a novel class 1 integron, In1814, at the downstream end of ISPa17. Here, blaIMP-10 together with aacA7 was located in In1814, being at evolution stage III of Tn402-associated integron due to truncation of the tni module. ConclusionThis study is the first to determine the complete sequence of a blaIMP-10-carrying plasmid, and this is also the first report of a blaIMP-10-producing strain in China. The prevalence of the blaIMP-10 gene and the genetic characterization of the blaIMP-10-carrying plasmid should be analyzed to provide deeper insight into the transmission mechanism of antimicrobial resistance genes.

Etiological Agents of Urinary Tract Infection and 7 Years Trend of Antibiotic Resistance of Bacterial Uropathogens in Sudan

Introduction: Bacterial infections of the urinary tract represent a major cause of outpatient visits as well as hospital-acquired infections. As the prevalence of multidrug-resistant uropathogens is increasing, updated knowledge of the commonest bacterial causes and their susceptibility patterns is crucial for the proper selection and use of antimicrobial drugs and the development of effective local prescribing guidelines. Methods: Handling of urine samples, identification of organisms and antimicrobial susceptibility testing were made according to guidelines in Monica Cheesbrough 2000, 2006. The prevalence of resistance of the pathogens against each antibiotic was calculated as the proportion of resistant isolates over the entire tested isolates. Data were analyzed using Epi info; the chi-square test and Fisher exact test were used to assess the statistical significance of results. Results: In this study, 774 samples were cultured from patients with suspected urinary tract infection (UTI), 705 (91%) urinary isolates showed significant growth (>105 CFU /L) while the other 69 samples showed no significant growth. 431 (61%) of the patients were female, while the other 274 (39%) were males. 13 types of pathogens were identified in 705 urinary isolates. E.Coli was the main bacterial uropathogen identified. Microbiological susceptibility of a total of 28 antibiotics was tested; for each urinary isolate, different sets of these antibiotics were used. 601(96%) of the bacteria were resistant to at least one antibiotic. 17 antibiotics were found to have a bacterial resistance rate of more than 50%, including all B lactams (except cefuroxime), Nalidixic acid, Ciprofloxacin, Norfloxacin, Clindamycin, Co-Trimoxazole and Tetracyclines(Tetracycline and Doxycycline). Other antibiotics were found to have resistance rates of less than 50%. Amikacin & Imipenem had the highest susceptibility rates. Throughout the 7 years, resistance to most of the antibiotics showed an incremental pattern. Conclusion: Current empirical antibiotic therapy for UTI should be modified, and new guidelines should be established based on local resistance rates. This study comes up with precious regional data for evidence-based empirical antibiotic treatment, but a national sentinel surveillance system and regional antibiograms should be established to track the bacterial susceptibility profiles in Sudan.

Understanding the risk of emerging bacterial resistance to over the counter antibiotics in topical sore throat medicines

The aims of this study were to explore the development of bacterial resistance and cross-resistance in four common human pathogens following realistic exposure to antibiotics found in over-the-counter (OTC) sore throat medicines: gramicidin, neomycin, bacitracin and tyrothricin. Bacterial exposure to in-use (concentration in the product before use) and diluted concentration (i.e. during use) of antibiotic where conducted in broth for 24h or until growth was visible. The changes in bacterial susceptibility profile before and after exposure was determined using standardized ISO microdilution broth. Antibiotic testing was performed according to EUCAST guidelines. We demonstrated that test bacteria were able to survive exposure to the in-use concentrations of some antibiotics used in OTC medicines. Exposure to during use concentrations of bacitracin resulted in stable increase in minimal inhibitory concentration (MIC) (>8-fold) in Staphylococcus aureus and Acinetobacter baumannii. Exposure to tyrothricin resulted in a stable increase in MIC (2·4-fold) in Klebsiella pneumoniae, and exposure to neomycin resulted in a stable increase MIC (5000-fold higher than the baseline) in Streptococcus pyogenes. Clinical cross-resistance to other antibiotics (ciprofloxacin, fusidic acid, gentamicin, cefpodoxime, amoxicillin/clavulanic acid and cefotaxime) was also demonstrated following exposure to bacitracin or tyrothricin. Bacitracin exposure lead to a stable bacterial resistance after 10 passages. Our results indicate that OTC antibiotic medicines have the potential to drive resistance and cross-resistance in vitro. Tackling antibiotic resistance is a high worldwide priority. It is widely accepted that the overuse and misuse of antibiotics increase the risk of the development and spread of antibiotic resistance within communities. A number of OTC sore throat products, widely available across the world for topical use in respiratory indications, contain locally delivered antibiotics. Our findings showed that these antibiotics in OTC medicines present a risk for emerging cross-resistance in a number of bacterial respiratory pathogens.

A broad-spectrum beta-lactam-sparing stewardship program in a middle-income country public hospital: antibiotic use and expenditure outcomes and antimicrobial susceptibility profiles

BackgroundAntimicrobial stewardship programs are an efficient way to reduce inappropriate use of antimicrobials and costs; however, supporting data are scarce in middle-income countries. The aim of this study was to evaluate antibiotic use, bacterial susceptibility profiles, and the economic impact following implementation of a broad-spectrum beta-lactam-sparing antimicrobial stewardship program. MethodsAn interrupted time-series analysis was performed to evaluate antibiotic use and expenditure over a 24-month period (12 months before the antimicrobial stewardship program and in the 12 months after implementation of the antimicrobial stewardship program). Antibiotics were classified into one of two groups: beta-lactam antibiotics and beta-lactam-sparing antibiotics. We also compared the antimicrobial susceptibility profiles of key pathogens in each period. ResultsBeta-lactam antibiotics use decreased by 43.04 days of therapy/1000 patient-days (p=0.04) immediately following antimicrobial stewardship program implementation, whereas beta-lacta-sparing antibiotics use increased during the intervention period (slope change 6.17 days of therapy/1000 patient-days, p<0.001). Expenditure decreased by $2089.99 (p<0.001) immediately after intervention and was maintained at this level over the intervention period ($−38.45; p=0.24). We also observed that a greater proportion of pathogens were susceptible to cephalosporins and aminoglycosides after the antimicrobial stewardship program. ConclusionsThe antimicrobial stewardship program significantly reduced the use of broad-spectrum beta-lactam-antibiotics associated with a decrease in expenditure and maintenance of the susceptibility profile in Gram-negative bacteria.

Hydroxyethoxy phenyl butanone, a new cosmetic preservative, does not cause bacterial cross-resistance to antimicrobials.

Introduction. Biocide-induced cross-resistance to antimicrobials in bacteria has been described and is a concern for regulators. We have recently reported on a new protocol to predict the propensity of biocide to induce phenotypic resistance in bacteria.Aim. To measure bacterial propensity to develop antimicrobial resistance following exposure to a new cosmetic preservative developed by L’Oréal R and I.Methodology. Well-established antimicrobials including triclosan (TRI) and benzalkonium chloride (BZC) and a new molecule hydroxyethoxy phenyl butanone (HEPB) were investigated for their antimicrobial efficacy, effect on bacterial growth, and their potential to induce resistance to chemotherapeutic antibiotics using a new predictive protocol.Results. The use of this predictive protocol with Staphylococcus aureus , Escherichia coli and Pseudomonas aeruginosa showed that TRI and BZC significantly affected bacterial growth, MICs and minimum bactericidal concentrations (MBCs). There was no change in antibiotic susceptibility profile following exposure to BZC, but E. coli became intermediate resistant to tobramycin following treatment with TRI (0.00002 % w/v). HEPB did not change the antimicrobial susceptibility profile in P. aeruginosa and S. aureus but E. coli became susceptible to gentamicin. TRI exposure resulted in bacterial susceptibility profile alteration consistent with the literature and confirmed the use of TRI as a positive control in such a test.Conclusion. Data produced on the propensity of a molecule to induce bacterial resistance is useful and appropriate when launching a new preservative.

Looking beyond Typical Treatments for Atypical Mycobacteria.

The genus Mycobacterium comprises not only the deadliest of bacterial pathogens, Mycobacterium tuberculosis, but several other pathogenic species, including M. avium and M. abscessus. The incidence of infections caused by atypical or nontuberculous mycobacteria (NTM) has been steadily increasing, and is associated with a panoply of diseases, including pulmonary, soft-tissue, or disseminated infections. The treatment for NTM disease is particularly challenging, due to its long duration, to variability in bacterial susceptibility profiles, and to the lack of evidence-based guidelines. Treatment usually consists of a combination of at least three drugs taken from months to years, often leading to severe secondary effects and a high chance of relapse. Therefore, new treatment approaches are clearly needed. In this review, we identify the main limitations of current treatments and discuss different alternatives that have been put forward in recent years, with an emphasis on less conventional therapeutics, such as antimicrobial peptides, bacteriophages, iron chelators, or host-directed therapies. We also review new forms of the use of old drugs, including the repurposing of non-antibacterial molecules and the incorporation of antimicrobials into ionic liquids. We aim to stimulate advancements in testing these therapies in relevant models, in order to provide clinicians and patients with useful new tools with which to treat these devastating diseases.

Comparison of Initial and Postlavage Bacterial Culture Results of Septic Peritonitis in Dogs and Cats.

Septic peritonitis is a common, life-threatening condition encountered in dogs and cats. Efficacy of peritoneal lavage has not been proven in veterinary studies. Our objective was to evaluate differences in bacterial identity and susceptibility in samples obtained pre- and postlavage in animals who underwent laparotomy for treatment of septic peritonitis and to assess the effect of empirical antimicrobial selection on survival. Culture samples were collected from the peritoneal surface pre- and postlavage from dogs and cats treated surgically for septic peritonitis. Culture results were compared for each patient with regard to bacterial isolates and bacterial susceptibility profiles. Survival to discharge was evaluated. Microbial growth occurred in at least one culture in 88.6% of patients. There was no significant difference in bacterial isolates or susceptibility profiles pre- versus postlavage. Positive culture pre- or postlavage and appropriate antimicrobial selection did not significantly affect survival. For individual animals, culture results differed between pre- and postlavage samples, although no definitive effect of peritoneal lavage was seen for the population as a whole. Antimicrobials most commonly effective against isolates were Cefotaxime, Ceftazidime, and Imipenem. If prompt surgical source control is employed, antibiotic choice may not affect clinical outcome.

The role of Enterococcus spp. and multidrug-resistant bacteria causing pyogenic liver abscesses

BackgroundPyogenic liver abscesses (PLA) remain a significant clinical problem. Unfortunately, little is known about current bacterial susceptibility profiles and the incidence of multidrug resistant organisms (MDROs) causing PLA in Western countries. Yet, this crucial information is pivotal to guide empirical antibiotic therapy. Aim of this study was to provide detailed characteristics of PLA with a special focus on underlying bacterial pathogens and their susceptibility to antibiotics.MethodsA retrospective study of patients diagnosed with PLA from 2009 to 2015 in a large tertiary reference center in Germany was performed in order to characterize PLA and antimicrobial susceptibility profiles of causative bacterial species.ResultsOverall, 86 patients were included. The most common causes of PLA were bile duct stenosis/obstruction (31.4%) and leakage of biliary anastomosis (15.1%). Frequent predisposing diseases were malignancies (34.9%), diabetes (24.4%) and the presence of liver cirrhosis (16.3%). Of note, Enterococcus spp. were the most frequently cultured bacterial isolates (28.9%), and in 1/3 of cases vancomycin resistance was observed. In addition, a relevant frequency of gram-negative MDROs was identified. In particular, an alarming 10% and 20% of gram-negative bacteria were resistant to carbapenems and tigecycline, respectively. Of note, MDRO status did not predict ICU stay or survival in multivariate regression analysis. The mortality rate in our series was 16.3%.ConclusionOur study demonstrates an as yet underreported role of Enterococcus spp., often associated with vancomycin resistance, as well as of gram-negative MDROs causing PLA.

Aislamiento bacteriano y la susceptibilidad microbiana en muestras biológicas de perros

Bacterial infections are of great importance in veterinary medicine and antimicrobial of choice must be made judiciously. This study aims to identify the bacteria and describe the bacterial susceptibility profile in biological samples of dogs sent for analysis in a particular laboratory in Belém, Pará, Brazil. For this, 59 biological samples were analyzed, 34 samples of ear secretion and 25 urine samples submitted for culture and sensitivity. Animal data such as sex, age and race were also considered and subsequently planned and analyzed in Microsoft Excel®. The main bacterial agent identified in ear secretions was Staphylococcus sp., while in urine samples Escherichia coli was the most frequent. None of the antimicrobial agents was able to inhibit the growth of the agents in this study, however, amikacin, ampicillin, ceftriaxone and imipenem obtained the best sensitivity results.

Prevalence and antimicrobial susceptibility profle of ESKAPE pathogens from the Federal District, Brazil

Introduction: the leading cause of hospital-acquired infections are the pathogens named by the acronym ESKAPE, which are the initials for the following bacterial: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa and Enterobacter spp., which have high resistance rates by escaping the action of the antimicrobial. Objective: to trace the antimicrobial susceptibility profile of the ESKAPE pathogens in a primary public hospital in the Federal District, Brazil. Methods: a cross-sectional, retrospective and descriptive study was conducted by analyzing the corresponding data from January 2010 to December 2015 of samples considered positive to ESKAPE pathogens in order to generate an antimicrobial susceptibility profile. Results: analyzing the Gram-positive bacteria, almost 80% of E. faecium strains were vancomycin-resistant enterococci (VRE) and almost 40% of S. aureus strains were methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). It was observed that gram-negative strains (the ESKAPE group) examined in this study have a higher resistance rate to carbapenems than in other studies. In the molecular analysis, four Klebsiella pneumoniae strains were positive to blaKPC gene, three strains to blaNDM and one Acinetobacter baumanni strain was positive to blaOXA-23 gene. Conclusion: studies such as this should be performed periodically in order to evaluate the bacterial susceptibility profile. They demonstrate the importance of implementing strategies to prevent hospital-acquired infections, as well as greater antibiotic prescribing control.

The effect of cationic microbicide exposure againstBurkholderia cepaciacomplex (Bcc); the use ofBurkholderia latastrain 383 as a model bacterium

The extensive use of microbicides in a wide range of applications has been questioned with regard to their role in the development of bacterial resistance to antimicrobials. This study aims to measure the phenotypic and genotypic changes in Burkholderia lata strain 383 exposed to chlorhexidine gluconate (CHG) and benzalkonium chloride (BZC), two commonly used cationic microbicides. The susceptibility of B. lata strain 383 to CHG and BZC and a range of antibiotics was determined using standardized MIC, MBC and antibiotic susceptibility testing protocols before and after short-term exposure to a low microbicide concentration. Measurements were performed on four separate occasions over a 1-year period. Changes in gene expression were investigated using quantitative real-time PCR. Although the susceptibility profile to CHG and BZC was not altered, a change in antibiotic susceptibility profile was observed for ceftazidime, and for imipenem and ciprofloxacin in 2/4 repeats. An outer membrane protein and ABC transporter were found to be significantly upregulated following treatment with BZC and CHG, respectively. The comparison of MIC and MBC results following microbicide exposure with baseline data offered a prospective protocol to quantify any change in bacterial susceptibility profile. However, the use of a standardized antibiotic susceptibility protocol with B. lata strain 383 showed some inconsistencies in results between repeats. With ever-increasing interest in the impact of microbicides on emerging antimicrobial resistance in bacteria growing, this study demonstrated that comparing susceptibility profile obtained after exposure to microbicides with baseline susceptibility values could play a role in establishing the potential risk of microbicide resistance and cross-resistance development and also in the development of a protocol that allows the prediction of microbicide resistance.

Fluorocyclines. 2. Optimization of the C-9 Side-Chain for Antibacterial Activity and Oral Efficacy

Utilizing a fully synthetic route to tetracycline analogues, the C-9 side-chain of the fluorocyclines was optimized for both antibacterial activity and oral efficacy. Compounds were identified that overcome both efflux (tet(K), tet(A)) and ribosomal protection (tet(M)) tetracycline-resistance mechanisms and are active against Gram-positive and Gram-negative organisms. A murine systemic infection model was used as an oral efficacy screen to rapidly identify compounds with oral bioavailability. Two compounds were identified that exhibit both oral bioavailability in rat and clinically relevant bacterial susceptibility profiles against major respiratory pathogens. One compound demonstrated oral efficacy in rodent lung infection models that was comparable to marketed antibacterial agents.

Exploring the antibacterial properties of honey and its potential

Exploring the antibacterial properties of honey and its potential

Actualización de la resistencia a antimicrobianos de bacilos Gram negativos aislados en hospitales de nivel III de Colombia: años 2006, 2007 y 2008

Antimicrobial resistance has been identified as one of the major public health problems worldwide. To facilitate its control, bacterial resistance levels must be monitored permanently by effective surveillance systems. To describe the antimicrobial resistance patterns of Gram negative bacilli in Colombian hospitals over a 3-year period. This descriptive study used the bacterial susceptibility profiles provided by 14 tertiary-care hospitals belonging to the Colombian Nosocomial Resistance Study Group. The hospitals were located in 7 major cities in Colombia, and provided records over the period January 2006 to December 2008. Using WHONET 5.4, the antimicrobial resistance patterns were described for the Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae) and non-fermenters (Pseudomonas aeruginosa and Acinetobacter baumannii). Comparisons were made in the bacterial responses to selected antibiotics in samples from general wards and from adult intensive care units. The antimicrobial resistance frequencies of several Enterobacteriaceae species showed a decreasing trend. In contrast, P. aeruginosa was demonstrated to be a multidrug-resistance organism with increasing resistance frequencies. These data emphasize the importance of surveillance programs in detecting presence of multidrug-resistant organisms. This information will aid the implementation of protocols aimed to strengthen the infection control strategies and antibiotic stewardship in each hospital.

Long-term epidemiology of bacterial susceptibility profiles in adults suffering from febrile neutropenia with hematologic malignancy after antibiotic change

The aim of this study was to investigate the epidemiology and antibiotic susceptibility profiles of isolated bacterial organisms in relation to empiric treatment of neutropenic fever over a 15-year period. All patients with or at risk for febrile neutropenia and treated in the hematology ward of the Antwerp University Hospital during 1994-2008 were prospectively included. Skin, blood, and urine cultures were taken. Oral quinolone prophylaxis was started in patients with neutropenia without fever. Empiric starting therapy consisted of amikacin in combination with cefepime. A total of 3624 bacteria were isolated. The most common pathogens were coagulase-negative Staphylococci (46%), followed by Escherichia coli (25%), Enterobacteriaceae (15.6%), Staphylococcus aureus (7.2%), and Pseudomonas aeruginosa (3.8%). The balance between Gram-positive and Gram-negative bacteria remained stable, with a majority of Gram-positive bacteria. A shift from oxacillin-sensitive to oxacillin-resistant coagulase-negative Staphylococci was observed. Regarding susceptibility patterns, no vancomycin resistance was detected in coagulase-negative Staphylococci or in S. aureus. The E. coli susceptibility rates remained stable. However, 66% of bloodstream infections were ciprofloxacin-resistant. A reduced susceptibility of P. aeruginosa strains to meropenem was noticed. Improvement in antibiotic susceptibility of inducible Enterobacteriaceae following a switch of empiric antibiotic therapy was maintained 15 years after starting the latter treatment. Further improvement in antibiotic susceptibility of these bacteria to ceftazidime was observed, but continuous vigilance is warranted.