Tigecycline: a critical update

Tigecycline is the first Food and Drug Administration (FDA) approved glycylcycline antibiotic. It has shown remarkable in vitro activity against a wide variety of gram-positive, gram-negative and anaerobic bacteria including many multidrug resistant (MDR) strains. However, it has minimal activity against Pseudomonas aeruginosa and Proteus spp. To date, little resistance to tigecycline has been reported. Clinical trials studying complicated skin and skin-structure infections (cSSSIs) demonstrated that tigecycline has equivalent efficacy and safety compared with the combination of vancomycin and aztreonam. For complicated intra-abdominal infections (cIAIs), tigecycline was found to be as effective as imipenem/cilastatin. Adverse events related to tigecycline therapy, i.e. nausea and vomiting, were tolerable. Currently available data suggest that tigecycline may play an important role in the future as a monotherapy alternative to older broad-spectrum antibiotics, such as advanced generation cephalosporins, carbapenems, fluoroquinolones, piperacillin/tazobactam, and gram-positive directed agents (e.g. daptomycin, linezolid and quinupristin/dalfopristin) for which resistance is being increasingly reported from all parts of the world.     

Comparative In Vitro Activity of Tigecycline Against Aerobic and Facultative Isolates Recovered from Hospitalized Patients: An Argentinean Multicenter Study

Abstract

Tigecycline, the 9-t-butylglycylamino derivative of minocycline is the first commercially available glycylcycline exhibiting an extended spectrum of antibacterial activity due to its capacity to evade the tetracycline ribosomal and efflux resistance mechanisms. We conducted a collaborative In Vitro study determining the activity of tigecycline compared to 14 antimicrobials against clinically relevant isolates obtained from adult patients hospitalized in 9 Argentinean institutions. Minimum inhibitory concentrations (MICs) were determined by the reference broth microdilution method. The number of isolates and MICs 50/90 (mg/L) for tigecycline were the following: Acinetobacter spp. 132 (0.5/1); Escherichia coli 220 (0.12/0.25); Klebsiella spp. 220 (0.5/1), Enterobacter spp. 205 (0.5/1); Serratia spp. 84 (0.5/2); Haemophilus influenzae 96 (0.25/0.5); Staphylococcus aureus 223 (0.12/0.25); Streptococcus pneumoniae 98 (≤0.25/1); S. agalactiae 51 (0.5/0.5); Enterococcus spp. 104 (0.06/0.12); Pseudomonas aeruginosa 169 (8/16). We conclude that tigecycline is a promising drug for the treatment of infections in hospitalized patients in Argentina.     

Susceptibility of 228 Non-fermenting Gram-Negative Rods to Tigecycline and Six Other Antimicrobial Drugs

Abstract

The aim of the study was to determine the in vitro activity of tigecycline and 6 other antimicrobial drugs used in clinical practice against 228 clinical isolates of nonfermenting Gram-negative rods (NFGNRs) including Acinetobacter spp. Stenotrophomonas maltophilia, and Pseudomonas aeruginosa. Minimum inhibitory concentrations (MICs) were determined according to the recommendations of the Clinical and laboratory Standards institute. For tigecycline, we used the criteria approved by the FDA. Almost 50% of the clinical isolates of Acinetobacter spp. were resistant to piperacillin/tazobactam, ciprofloxacin, gentamicin, and ceftazidime. Strains of this microorganism were more susceptible to imipenem, and even more susceptible to colistin and tigecycline; no strains were resistant to tigecycline. Stenotrophomonas maltophilia showed even greater resistance to the drugs tested. Thus, all strains were resistant to imipenem and a large percentage (82.6%) were resistant to piperacillin/tazobactam. Resistance to the other agents tested was also high, with the exception of tigecycline, with only 3 resistant strains (MIC <8 mg/ml). Tigecycline, on the other hand, was scarcely active against Pseudomonas aeruginosa, which bears efflux pump systems such as MexXY-OprM. Almost 90% of strains were resistant to ciprofloxacin; only 8% were resistant to gentamicin; over half were colistin-intermediate or -resistant, and finally, approximately half of the strains were susceptible to the 3 beta-lactams studied. In conclusion, NFGNRs present variable susceptibility patterns, although they are generally highly resistant to antimicrobial agents including those considered more specific. Tigecycline, which showed good activity against most of the strains examined, broadens the spectrum of drugs available for the treatment of infections caused by these complex microorganisms.     

Aetiology and antibiotic resistance issues regarding urological procedures

Abstract

There are specific indications in urological procedures [transurethral resection of the prostate (TURP), transurethral resection of the bladder (TURB), endoscopic procedures, and all interventions classified as contaminated or dirty] requiring antibiotic prophylaxis. Most postoperative infections are caused by enterococci of the Gram-positive strains and Enterobacteriaceae of the Gram-negative ones. As reported by the European Center for Disease Prevention and Control (ECDC), there are increasing numbers of antibiotic-resistant pathogens. Most Enterococcus faecium strains are ampicillin-resistant and the Enterobacteriaceae have a high prevalence of extended-spectrum beta-lactamase (ESBL) producers, for which the cephalosporins and penicillins are not drugs of choice. In recent years, there are also increasing numbers of Gram-negative strains that are able to produce carbapenemases and for which the only therapeutic options are gentamicin, tigecycline and colistin. An alternative to these drugs, from a prophylactic point of view, is fosfomycin, an old antibiotic that maintains bactericidal activity against both enterococci and multidrug-resistant Enterobacteriaceae. Available in an oral formulation as trometamol salt, fosfomycin reaches high plasma and urine concentrations, and is therefore a possible alternative to other drugs both for therapy and urological prophylaxis.     

Antimicrobial Activity of Daptomycin Tested Against Gram-Positive Strains Collected in European Hospitals: Results from 7 Years of Resistance Surveillance (2003-2009)

Abstract

Daptomycin is a cyclic lipopeptide approved by the European medicines Agency (EMEA) for the treatment of complicated skin and soft tissue infections (cSSTI) and Staphylococcus aureus bacteremia and endocarditis. We evaluated the in vitro activity of daptomycin and comparators tested against clinical isolates from European hospitals over a 7-year period (2003-2009). A total of 36,769 consecutive isolates were collected in 34 medical centers located in 13 European countries, turkey and Israel. the collection included S. aureus (18,352; 27.2% oxacillin-resistant [MRSA]); coagulase-negative staphylo-cocci (CoNS; 6,874), Enterococcus spp. (7,241; 9.4% vancomycin-resistant),β-hemolytic (3,009), viridans group streptococci (1,176), and Streptococcus bovis/gallolyticus (107). The organisms were isolated mainly from patients with bloodstream infection (56%) or cSSTI (23%). Daptomycin was very active against S. aureus and CoNS (MIC_50/90, 0.25/0.5 mg/L for both organisms), and its activity was not adversely influenced by oxacillin resistance. All Enterococcus faecalis strains were susceptible to daptomycin (MIC_50/90, 1/1 mg/L). Daptomycin (MIC_50/90, 2/2 mg/L; 100.0% susceptible) and linezolid (MIC_50/90, 1/2 mg/L; 99.7% susceptible) were the most active agents tested against vancomycin-resistant E. faecium. Vancomycin-resistant and -susceptible enterococcal strains were equally susceptible to daptomycin. Daptomycin was also active against β-hemolytic streptococci (MIC_50/90, 0.06/0.25 mg/L; 100.0% susceptible), viridans group streptococci (MIC_50/90, 0.25/0.5 mg/L; 99.8% susceptible) and S. bovis (MIC_50/90, 0.06/0.12 mg/L; 100.0% susceptible).

In summary, daptomycin was very potent against this large collection (36,769) of Gram-positive organisms isolated in European hospitals, and its activity remained stable across the 7-year period evaluated (2003-2009), using reference methods and interpretive criteria. Decreases in daptomycin potency were not observed since EMEA approval and widespread clinical use, and emerging resistance to other compounds did not adversely influence daptomycin activity against contemporary Gram-positive species.     

Antimicrobial Spectrum and Potency of Dalbavancin Tested Against Clinical Isolates from Europe and North America (2003): Initial Results from an International Surveillance Protocol

Abstract

Dalbavancin is a bactericidal dimethylaminopropyl amide glycopeptide derivative possessing an extended serum elimination half-life in humans that allows onceweekly dosing for the therapy of Gram-positive infections. Strains from this baseline surveillance protocol in North America (NA; USA and Canada) and Europe (EU, 14 countries) were sampled in 2003. A total of 7,765 Gram-positive isolates (3,695 from NA and 4,070 from EU) were tested by reference broth microdilution methods against dalbavancin and 10 comparator agents. Species were analyzed separately by resistance phenotypes such as methicillin- (oxacillin-) resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and penicillin- resistant Streptococcus pneumoniae. Dalbavancin and other glycopeptides were very active against staphylococci (n=4648) with dalbavancin being 16- to 32- fold more potent than vancomycin (MIC₉₀, 0.06 versus 2 mg/L). MRSA rates were greater (31.6%) in NA than in EU (26.1%). Quinupristin/dalfopristin resistance (MIC, ≥ 2 mg/L; 0.1 - 0.5%) was documented more often in EU compared to NA. Dalbavancin (MIC₅₀, 0.03 - 0.06 mg/L) was active against enterococci, except VanA resistance phenotypes. VRE rates were lower in EU (8.3%) then in NA (35.9%) from this resistance-enhanced enterococcal collection. Streptococci (dalbavancin MIC₉₀, 0.016 - 0.03 mg/L) were generally most susceptible to glycopeptides (100.0%), quinupristin/dalfopristin (98.6 - 100.0%) and linezolid (100.0%); but dalbavancin was 16-fold more active than comparators. All vancomycin-susceptible enterococci and > 90% of vanB VRE had dalbavancin MIC values at ≤ 1 mg/L, but vanA VRE strains had dalbavancin MIC results ranging from 0.06 to > 8 mg/L (median MIC, ≥ 8 mg/L). Dalbavancin MIC values were not adversely influenced by geographic region or resistance phenotype (except vanA VRE). Infrequently isolated Gram-positive organisms such as Bacillus spp. (MIC₉₀, 0.12 mg/L), Corynebacterium spp. (MIC₉₀, 0.12 mg/L), Listeria monocytogenes (MIC₉₀, 0.25 mg/L) and Micrococcus spp. (MIC₉₀, 0.03 mg/L) were very susceptible to dalbavancin. In conclusion, these 2003 baseline resistance surveillance findings confirm the potent dalbavancin activity compared to several comparator agents against important Gram-positive pathogens. This high volume international survey indicates potential therapeutic roles for dalbavancin against many troublesome resistant Gram-positive phenotypes.     

Antimicrobial susceptibility among E. faecalis and E. faecium from France,Germany, Italy,Spain and the UK (T.E.S.T. Surveillance Study, 2004-2009)

Abstract

We report on antimicrobial activity against E. faecalis and E. faecium collected in France, Germany, Italy, Spain, and the UK between 2004 and 2009 as part of the Tigecycline Evaluation and Surveillance Trial (UK in vitro data not included due to low isolate numbers). Overall, 1·1% (n?=?23/2068) of E. faecalis and 11·5% (n?=?103/893) of E. faecium were vancomycin-resistant. High levels of minocycline-resistant E. faecalis were reported in Germany, Spain, France, and Italy (40·2–44·2%); levofloxacin resistance was high in Germany, Italy, and Spain (31·1–41·6%). Minocycline non-susceptibility increased significantly among E. faecalis in Spain and Italy (P<0·001). No tigecycline-resistant E. faecalis were reported. Among E. faecium, resistance ranged from 72·9% (France) to 93·3% (Germany) for ampicillin, from 56·1% (France) to 90·2% (Germany) for levofloxacin, and from 75·3% (Italy) to 94·7% (Germany) for penicillin. Levofloxacin non-susceptibility increased significantly among E. faecium in France and Spain (P<0·001). The lowest rates of antimicrobial resistance among E. faecium were reported for tigecycline (2/893; 0·2%) and linezolid (3/893; 0·3%).     

Tigecycline as a therapeutic option in Stenotrophomonas maltophilia infections

Abstract

Trimethoprim-sulfamethoxazole (TMP-SMZ) is recommended as the treatment of choice for Stenotrophomonas maltophilia infections. However, when the administration of TMP-SMZ is not possible, alternative treatment options for S. maltophilia infections has not been clearly established. We compare the efficacy of tigecycline treatment with TMP-SMZ in nosocomial S. maltophilia infections during a 3-year period. For the treatment of S. maltophilia infection, 26 (57·8%) patients received TMP-SMZ and 19 (42·2%) patients received tigecycline. Culture positivity rate was 95·7% in TMP-SMZ group and 70·6% in tigecycline group at the seventh day (P?=?0·028), whereas 26·3% versus 18·8% at the fourteenth day (P?=?0·700). Clinical improvement was observed 69·2% in TMP-SMZ group and 68·4% in tigecycline group at the fourteenth day (P?=?0·954). Mortality rates at the thirtieth day were respectively, 30·8 and 21·1% in TMP-SMZ and tigecycline groups (P?=?0·517). There were no significant differences in mortality and clinical response rates between TMP-SMZ and tigecycline treatment. Tigecycline can be considered as an alternative option beyond TMP-SMZ in treatment of S. maltophilia infections.     

Hepatocyte growth factor protects the liver against hepatitis C virus in patients on regular hemodialysis

Abstract

Propolis is produced by bees and is reported to have several pharmaceutical properties. Its antibacterial activity against strains causing upper respiratory tract infections is particularly important: Propolis might be used as a therapeutic agent to prevent the bacterial infections that sometimes overlap viral infections.

In this study the in vitro activity of both an alcoholic solution and a hydroglyceric extract of Propolis as well as its active principles, was tested against bacteria responsible for respiratory infections (Streptococcus pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis and Streptococcus pyogenes).

We also evaluated the in vitro activity of a combination of propolis and its active principles and some beta-lactams, macrolides and fluoroquinolones. Our results, though not demonstrating a clearly synergistic activity between antibiotics and Propolis and its constituents, show the possibility of using natural preparations, due to their antimicrobial and anti-inflammatory properties, to enhance antibacterial therapy.     

An Observational Study on the Epidemiology of Respiratory Tract Bacterial Pathogens and Their Susceptibility to Four Injectable Beta-Lactam Antibiotics: Piperacillin,Piperacillin/Tazobactam,Ceftazidime and Ceftriaxone

Abstract

Bacterial infections of the respiratory tract account for a large proportion of total medical consultations in general practice. In recent years, antibiotic resistance has increased alarmingly in a number of bacterial species that are common causes of these infections. The aim of this observational study was to determine the antibiotic resistance of microbial agents isolated from patients with acute or acutely exacerbated respiratory infections. Subjects recruited as potential sources of bacteria were either outpatients seen in a number of specialized clinics and hospital practices, or hospitalized patients. Overall, 64-a8 consecutive patients (67% male, mean age 48.1 ± 27.0 years) with infection of the upper or lower respiratory tract were observed during a 13-month period. A total of 551 pathogenic microbial strains were isolated and tested for their in vitro susceptibility to piperacillin, piperacillin/tazobactam, ceftazidime, and ceftriaxone. Among all isolates, the four most frequent pathogens were Pseudomonas aeruginosa (132 isolates, 24%), Streptococcus pyogenes (99 isolates, 18%), Staphylococcus aureus (93 isolates, 17%), and Klebsiella pneumoniae (46 isolates, 8%). The susceptibility of Gram-positive isolates ranged from 97.5% to 95.1%, and no remarkable difference was found in the antibacterial activity of tested b-lactam antibiotics. The susceptibility of Gram-negative isolates to piperacillin and piperacillin/tazobactam was also similar: 96.5% and 97.1%, respectively. In contrast, differences were found between piperacillin (or piperacillin/tazobactam) and either ceftazidime (p=0.003) or ceftriaxone (p<0.0003) in Gram-negative isolates.

We conclude that, despite the extensive use of beta-lactam antibiotics (piperacillin, ceftazidime, and ceftriaxone) in medical practice during the past three decades, the susceptibility of the most common pathogens involved in the etiology of upper and lower respiratory tract infections to these antibiotics is still high. In particular, bacterial resistance developed by Gram-positive organisms against piperacillin is negligible and not alarming.     

Successful Treatment of Murine Listeriosis and Salmonellosis with Levofloxacin

Abstract

Levofloxacin (L-ofloxacin) is a fluoroquinolone derivative. It is the active substance contained in ofloxacin with a broad spectrum of antibacterial activity against both Gram-negative and Gram-positive bacteria. In this work we examined the activity of levofloxacin against the facultative intracellular bacteria Listeria monocytogenes and Salmonella typhimurium in vitro, in tissue culture and in animal models of infection. The minimum inhibitory concentrations (MICs) MIC₉₀ for Salmonella enterica and L. monocytogenes were 0.078 mg/l and 4 mg/l, respectively. Levofloxacin was bactericidal against L. monocytogenes and S. typhimurium because 8 × MIC killed 90% of the initial inoculum of L. monocytogenes EGD and S. typhimurium LT2 within 4 hours and 3 hours, respectively. Levofloxacin was more effective than ampicillin against L. monocytogenes EGD infecting tissue culture cells. Also in tissue culture cells infected with S. typhimurium LT2, levofloxacin was slightly more effective than ciprofloxacin. In animal models of infection, levofloxacin was as potent as the reference substances. In conclusion, levofloxacin is a candidate for the treatment of infections caused by facultative intracellular Gram-positive and Gram-negative bacteria.     

Surgical technique and biomaterials for totally implanted port catheter systems

Abstract

The antibacterial activity of S-4661, a new parenteral carbapenem antibiotic, was assessed against the major urological pathogens isolated from patients with complicated urinary tract infections. S-4661 was slightly less active than imipenem and panipenem, but more active than meropenem and ceftazidime against Gram-positive bacteria. Against Gram-negative bacteria, S-4661 was similar to meropenem, similar to or more effective than imipenem, and more active than panipenem and ceftazidime. Thus S-4661 possesses potent and well-balanced wide-spectrum antibacterial activity against various urological pathogens.     

Fourth Generation Cephalosporins in the Antimicrobial Chemotherapy of Surgical Infections

Abstract

Surgical infections include a variety of entities such as secondary peritonitis, intra-abdominal abscesses, obstetric and gynecological infections as well as bone-joint and soft-tissue infections. By definition the term “surgical infection” implies that surgery itself plays the major role in therapy, while antimicrobial chemotherapy is only supplementary. Broad-spectrum empirical regimens employed include the combination of a 1^st or 2^nd generation cephalosporin plus clindamycin or metronidazole ± aminoglycoside (depending on the severity of the condition). Cefepime and cefpirome are new 4^th generation parenteral cephalosporins with a spectrum of activity which makes them suitable for the treatment of infections caused by a wide variety of bacteria. They are active against both Gram-positive and Gram-negative organisms, including Staphylococcus aureus and Pseudomonas aeruginosa with activity comparable to or greater than that of cefotaxime or ceftazidime respectively. Cefepime in particular is also very active against strains of Enterobacter and Pseudomonas spp resistant to these two agents. In comparison with 3^rd generation cephalosporins, cefepime appears to be less likely to induce resistance, due to a lower rate of hydrolysis by ß-lactamases, a low affinity for these enzymes and more rapid permeation into the cell. Despite the fact that a 4^th generation cephalosporin is well-suited for the treatment of polymicrobial infections, the following should be kept in mind: (I) MRSA strains and Bacteroides fragilis group are not included in their spectrum of activity. (II) Cefpirome is the only cephalosporin with in vitro activity against Enterococci. (III) Severe surgical infections of nosocomial origin, and particularly in settings where Enterobacter spp predominate, represent the major indication for empirical use of a 4^th generation cephalosporin in combination with a nitroimidazole.     

Eight-year (2002-2009) Summary of the Linezolid (Zyvox® Annual Appraisal of potency and Spectrum; ZAAPS) Program in European Countries

Abstract

The linezolid surveillance network (ZAAPS program) has been monitoring linezolid activity and susceptibility rates for eight years (2002-2009) in European medical centers. Samples from 12-24 sites annually in 11 countries were monitored by a central laboratory design using reference MIC methods with international and regional interpretations (EUCAST). A total of 13,404 Gram-positive pathogens were tested from 6 pathogen groups. Linezolid remained without documented resistance from 2002 through 2005, but beginning in 2006 resistant strains emerged at very low rates among Staphylococcus aureus (G2576T mutant in ireland, 2007), coagulase-negative staphylococci (CoNS; usually Staphylococcus epidermidis, France and italy in 2006-2009) and enterococci (Enterococcus faecium in Germany [2006, 2008, 2009] and E. faecalis in Sweden [2008], United Kingdom [2008] and Germany [2009]); all but one strain having a target mutation. A mobile cfr was detected in an italian CoNS strain (2008 and 2009), and clonal spread was noted for linezolid-resistant strains (pfGe results). Overall the linezolid susceptibility rates were >99.9, 99.7 and 99.6% for S. aureus, CoNS and enterococci, respectively; and all streptococcal strains were susceptible (MIC₉₀, 1 mg/L). In conclusion, the ZAAPS program surveillance confirmed high, sustained levels of linezolid activity from 2002-2009 and without evidence of MIC creep or escalating resistance in Gram-positive pathogens across monitored European nations.     

In Vitro Combinations of Five Intravenous Antibiotics with Dalfopristin-Quinupristin Against Staphylococcus aureus in a 3-Dimensional Model

Abstract

We compared the in vitro activity of dalfopristin and quinupristin combined with five intravenous antibiotics in a 3-dimensional model. We tested six strains of Staphylococcus aureus selected with different patterns of resistance to methicillin and eryth-romycin. Dalfopristin and quinupristin displayed a very synergistic activity against all the strains with a mean 16- or 32-fold decrease of inhibitory concentrations in combination. That synergy was even better against erythromycin-resistant strains. In combination with tigecycline or fosfomycin, the antibacterial activity could be consistently enhanced with the same decrease of inhibitory concentrations. A synergy was also observed, less regularly and at a lower level, with rifampin, gentamicin or vancomycin. Combinations of dalfopristin and quinupristin with tigecycline or fosfomycin could be very interesting in clinical practice because the inhibitory effect could be achieved with very low oncentrations of each component, even when erythromycin-resistant strains are concerned.     

A systematic review of implications,mechanisms, and stability of in vivo emergent resistance to colistin and tigecycline in Acinetobacter baumannii

The potential of A. baumannii for acquired resistance to last resort antibiotics (colistin and tigecycline) during treatment has important clinical implications, especially when dealing with patients failing to improve despite treatment with an active antimicrobial. However, the relevant literature remains scattered. Therefore, a systematic search was conducted in PubMed and Scopus. Several studies reported emergence of resistance to colistin or tigecycline during treatment, in most cases (86%) resulting in persistent or recurrent infections, especially in cases of emergent resistance without fitness cost. Lipopolysaccharide modification in the case of colistin and overexpression of efflux pumps in the case of tigecycline were the main mechanisms of resistance. Emergent colistin resistance is often associated with fitness cost which may result in re-emergence of the fitter and more virulent colistin susceptible strain after cessation of antibiotic pressure. Prospective studies are needed to determine the frequency of emergent resistance during treatment and its impact on patient outcomes.     

Bacterial Isolates from Severe Infections and Their Antibiotic Susceptibility Patterns in Italy: a Nationwide Study in the Hospital Setting

Abstract

The most frequent agents of severe bacterial infections and their antibiotic susceptibility patterns were determined in patients admitted to 45 Italian hospitals over the years 2002-2003. The most common diagnoses were: sepsis (33.8%), pneumonia (9.4%), intravascular catheter-associated infections (9.3%) and ventilator- associated pneumonia (8.1%). Overall, 5115 bacterial isolates were identified from 4228 patients. Three bacterial species, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, accounted for more than 50% of the isolates. Other prevalent bacterial isolates were Staphylococcus epidermidis and Enterococcus faecalis, while Acinetobacter baumanii ranked third among all Intensive Care Unit (ICU) isolates. 7% of S. aureus had intermediate resistance to vancomycin. Although E. faecalis displayed no vancomycin resistance, 34% of vancomycin- resistant isolates were found among Enterococcus faecium, one of the highest rates found to date, emphasizing the difference between these two enterococcal species. All the Gram-positive pathogens were susceptible to linezolid, with the exception of approximately 2% of the enterococcal isolates that were intermediate with a minimum inhibitory concentration (MIC)=4 μg/ml. Almost 10% of Escherichia coli, 14% of Klebsiella pneumoniae, 22% of Serratia marcescens and 50% of Enterobacter cloacae were non-susceptible to cefotaxime. Amikacin was the most active antibiotic against P. aeruginosa that showed lack of susceptibility to ceftazidime, gentamicin, piperacillin and ciprofloxacin ranging from 20 to 35%. Finally, Acinetobacter baumanii showed a high level of resistance to all the antibiotics tested including imipenem (58%). The results obtained in this study, the first of its kind in Italy, offer indications for guiding empirical therapy and implementing specific interventions to fight antibiotic-resistant bacterial infections and their transmission in the hospital setting in Italy.     

Antibiotic resistance patterns of Gram-negative and Gram-positive strains isolated from inpatients with nosocomial infections in a tertiary hospital in Beijing,China from 2011 to 2014

This study was to evaluate the resistance of antimicrobial agents against pathogens from inpatients with nosocomial infection collected in Beijing, China, during 2011–2014. Measurement of minimum inhibitory concentrations (MICs) was carried out using the broth microdilution method with the Clinical and Laboratory Standards Institute (CLSI) guidelines as the indicator. A total of 5442 Gram-negative and 806 Gram-positive isolates were collected in this study in 2011–2014. Two carbapenem-resistant strains appeared among Escherichia coli (E. coli), while imipenem-resistant isolates increased in proportion from 0% to 8.2% among Klebsiella pneumonia (K. pneumonia) during 4 year. Acinetobacter baumannii (A. baumannii) revealed severe antibacterial resistance to most antimicrobial agents. In contrast, a decreasing trend on resistance had been observed among Pseudomonas aeruginosa (P. aeruginosa) especially after 2012, range from 1.8% for co-trimoxazole to 13.5% for piperacillin. The resistance of Staphylococcus aureus (S. aureus) also had the lowest resistant to linezolid and vancomycin (0.1%). In summary, antimicrobial-resistant nosocomial pathogens have gradually increased from 2011 to 2014, so improved surveillance of hospital-acquired infections and effective infection-control measures may be the best way to solve the present problem.     

DR. ZECKEL'S REPLY:

Abstract

The aim of the study was to monitor the prevalence of pathogens and development of resistance in bacteria isolated from bacteremic patients.

Five University Clinics and/or Regional Hospitals in the Slovak Republic participated in the study and a total of 421 isolates were collected in the second half of the year 2002. The most prevalent organisms were coagulase-negative staphylococci (CONS) (19%) Staphylococcus aureus (18.3%), among Gram-negative bacteria Escherichia coli (13.3%) Klebsiella pneumoniae (11.4%) and Pseudomonas aeruginosa (7.8%) followed by enterococci Acinetobacter baumannii and Enterobacter sp. All CONS and S. aureus were susceptible to vancomycin; resistance to oxacillin was observed for 55% of the CONS and only for 4% of S. aureus isolates. A higher prevalence of resistance to erythromycin, clindamycin, gentamicin and ofloxacin was found in CONS in comparison to S. aureus. Enterococcus sp. isolates were fully susceptible to vancomycin and teicoplanin. Gentamicin, amoxicillin/ clavulanate, third generation cephalosporins and ciprofloxacin showed good activity against E. coli. Although 17% of K. pneumoniae isolates were resistant to ciprofloxacin, it was the most effective drug against K. pneumoniae; the prevalence of resistance to other antibiotics was rather higher. Gentamicin and ciprofloxacin were the most active against Enterobacter sp. isolates and ceftazidime and meropenem against P. aeruginosa.