Rev Esp Quimioter 2008;21(Núm. Ext. 1):2-6

Problematic bacteria

J. L. Muñoz Bellido 

  

Introduction. Because of the special characteristics of the critical patients, infections are one of the primary complications they suffer so that multiresistant microorganisms take on a special importance in this type of patient.

Sources. Search in Medline using the words ICU (Intensive Care Unit), multidrug resistant, critical patient.

Development. Glycopeptide resistant enterococci show a reduced prevalence in our setting and the VISA and hVISA are isolated sporadically. MRSA is, on the other hand, a major problem. In 2003-2005, it was already accounting for 28%-38% of the S. aureus isolated in the ICU, with a high percentage of fluoroquinolone (>90%) and macrolide (>65%) co-resistance. The extended-spectrum beta-lactamase producing enterobacteria (BLEE) also are a growing problem, worsened by their frequent co-resistance with fluoroquinolones, about 30% according to some studies. Carbapenem resistance in A. baumannii has doubled in recent years, with values greater than 50%, almost always associated to enzymes of the OXA group. P. aeruginosa also maintains high resistance values (25%-30% of resistance to imipenem, ceftazidime or ciprofloxacin), but more stable. However, high rates of multi-resistance are also observed, now about 50% of the isolations of imipenem resistant P. aeruginosa are also to fluoroquinolones. As a whole, recent studies show that the multiresistance has multiplied in recently years by 5 in P. aeruginosa and by 7 in A. baumannii. Conclusions. Multiresistant bacteria infections are one of the greatest problems to combat in critical patients and control of their spreading and the development of active antimicrobials against them is one of the principal challenges at present.

  

Key words: Critical patients. Intensive Care Unit (ICU). Multi-resistant bacteria. Nosocomial infection. Resistance 

 

Rev Esp Quimioter 2008;21(Núm. Ext. 1):2-6 [pdf]  

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Rev Esp Quimioter 2008;21(4):234-258

Guidelines for the treatment on infections caused by methicillin-resistant Staphylococcus aureus

J. Mensa ,  J. Barberán ,  P. Llinares ,  J.J. Picazo ,  E. Bouza ,  F. Álvarez-Lerma ,  M. Borges Sá ,  R. Serrano ,  C. León ,  Xavier Guirao Garriga ,  J Arias ,  E Carreras ,  M Sanz ,  J. Á. García Rodríguez 

  

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) have undergone important changes in the last five years that have influenced the choice of therapy: i) increase of their frequency in hospital-associated settings and, more recently, in community settings; ii) better knowledge of clinical implications of the pharmacokinetic and pharmacodynamic properties of vancomycin; iii) improvement of current standard methods for rapid detection of MRSA in clinical samples; iv) clear evidence that vancomycin is losing efficacy against MRSA with MIC > 1 μg/mL; and v) appearance of new antibiotics suitable for use in these infections (linezolid, daptomycin, tigecyclin). Under this situation guidelines for the treatment of common infections caused by MRSA appear to be necessary to improve the efficacy and reduce the mortality.

 

Key words: Methicillin-resistant S. aureus (MRSA). MRSA guidelines. New antibiotics.

Rev Esp Quimioter 2008;21(4):234-258 [pdf] 

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Rev Esp Quimioter 2008;21(4):224-233

Hepatotoxicity by antibiotics: update in 2008

M. Roble ,  R. J. Andrade 

  

Although antibiotics are the most commonly incriminated drugs in instances of hepatotoxicity in medical literature. However, it is mainly due to its wide prescription and the absolute risk of hepatotoxicity related to antibiotic use is thought to be low. Nevertheless, among the different penicillins, amoxicillin-clavulanate is the single leading drug involved in hepatotoxicity in cohorts of patients with druginduced liver injury (DILI), representing between 12.8% to 14% of the cases. It is the most frequent cause of hospitalization for DILI. The incidence of amoxicillin-clavulanate induced hepatotoxicity has been estimated to be 9.91 per 100 000 users and its clinical presentation varies, the type of injury strongly influenced by age, with the hepatocelullar pattern predominating in younger patients and the cholestatic/mixed ones in older subjects. Among macrolides, erythromycin is a classical example of drug capable of inducing cholestatic injury. Recently, concern has arisen regarding telithromycin, a new generation macrolide, is hepatotoxic came from the identification of several cases of DILI related to this drug, with a typical signature, including abrupt commence of fever, abdominal pain, jaundice and ascites in some cases. Tetracyclines, especially in intravenous high doses, may be associated with dose-dependent microvesicular steatosis, and minocycline has been involved in an autoimmune like type I hepatitis. Quinolones, in spite of their extensive use in patients with cirrhosis and biliary infections, have been very rarely associated with hepatotoxicity.

 

Keywords: Hepatotoxicity. Antibiotics. Amoxicillin-clavulanate. Age.

 

Rev Esp Quimioter 2008;21(4):224-233 [pdf]

 

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Rev Esp Quimioter 2008;21(4):217-223

Staphylococcus aureus bacteremia in Castellón General Hospital (2001-2005)

S. Sabater Vidal ,  R. Moreno Muñoz 

  

Objective. The aim of this study was to know the frequency of bacteremias produced by Staphylococcus aureus and the sensibility that strains showed, as well as the clinical characteristics of the patients.

Method. We retrospectively studied cases of S. aureus bacteremia detected in our hospital from 2001 to 2005 and also reviewed medical histories from patients during 2005.

Results. A total of 295 cases of S. aureus bacteremia were detected in this study. Annual distributions of the cases were as follows: 35, 54, 62, 64 and 80. By gender, 62.7 % related to males and 37.3 % to females. A total of 58.6 % of the patients were admitted to medical services and 49 % were older than 65 years. Regarding resistance, 34 % of the strains showed resistance to oxacillin, 33 % to ciprofloxacin, 41 % to erythromycin and 4.4 % to gentamicin. In one-third of the patients, S. aureus was isolated in other samples, the catheter being the most common. A total of the 73.5 % of the patients had some baseline disease and the most frequent predisposing factor was the intravascular catheter. The bacteremias were nosocomial-acquired in 73.5 % of the cases.

Conclusions. In our hospital, S. aureus bacteremia and oxacillin resistance has been increasing over the years of this study.    

 

Key words: Staphylococcus aureus. Bacteremia. Oxacillin resistance. Catheter. Nosocomial.   

 

Rev Esp Quimioter 2008;21(4):217-223 [pdf]

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Rev Esp Quimioter 2008;21(4):213-216

Evaluation of the cefoxitin 30 μg disk diffusion method for detection of methicillin-resistance in selected Staphylococcus aureus isolates

N. Batista Díaz ,  I. Gutiérrez González ,  M. Lara Pérez ,  F. Laich ,  S. Méndez Álvarez 

  

Oxacillin tests may fail to detect some methicillinresistant S. aureus populations. The objective of this study is to evaluate the discriminative capacity of the Clinical and Laboratory Standards Institute (CLSI) disk diffusion method with a cefoxitin 30 μg disk on S. aureus isolates with unusual phenotypic characteristics of antimicrobial resistance. We studied 53 clinical S. aureus isolates. The antimicrobial susceptibility of all isolates was routinely studied by the VITEK 2 System (bioMérieux). Methicillin resistance was also studied by CLSI oxacillin method and confirmed by a previously described multiplex polymerase chain reaction (PCR) method which permits S. aureus identification and simultaneous detection of methicillin resistance. MecA positive isolates presenting a diffuse growth within the zone of inhibition when exposed to oxacillin were considered heteroresistant; mecA negative, oxacillin intermediate or resistant isolates were considered borderline. All the isolates were tested with a cefoxitin 30 μg disk, according to the CLSI guidelines (susceptibility: > 22 mm; resistance: < 21 mm). Control strains for all assays included MRSA ATCC 43300 and MSSA ATCC 25923. The isolates formed four groups. Group I: 20 multiresistant, oxacillin susceptible and mecA negative isolates; group II: 16 resistant or with intermediate oxacillin susceptibility and mecA negative isolates; group III: 11 heteroresistant and mecA positive isolates; group IV: six mecA positive isolates with atypical resistance profiles (penicillin and oxacillin, or ciprofloxacin and erythromycin resistance). Thirty-five mecA negative isolates included in groups I and II showed inhibition zones > 22 mm; one isolate from group II showed 20 mm. The 17 mecA positive isolates from groups III and IV showed resistance to cefoxitin disk. The 30 μg cefoxitin disk diffusion method is proposed as an efficient method for the detection of methicillin resistance and permits a clear determination set S. aureus isolates, even those with atypical antimicrobial characteristics.

  

Key words: Staphylococcus aureus. Cefoxitin. Methicillin-resistance

 

Rev Esp Quimioter 2008;21(4):213-216 [pdf]

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Rev Esp Quimioter 2008;21(4):206-212

A day in Spanish microbiology. Descriptive study of the activity of the clinical microbiology departments

J. Prieto ,  J. Á. García Rodríguez ,  J. Barberán ,  J. J. Granizo ,  M. P. Rodicio ,  J. González     

Introduction. The laboratory is an essential part of the work in the Clinical Microbiology Department. This study has aimed to measure the activity of these laboratories.

Material and methods. A survey was self-administered on the activity occurring during one work day by each hospital in October 2007.

Results. Thirty six hospitals reported 14,076 tests. Serology was the most frequently reported test (30.3%) followed by urine culture (27.8 %), blood tests (13.2 %), respiratory tract samples (8%), feces (7.1%), urethral (5.8%), skin (5.3%) and cerebrospinal fluid (2.6%). According to species, 73.2% of the isolates were bacteria (22.9 % were positive), 8.9% were virus (17% positive), fungi 8.1% (25.2% positive), and 5.5% mycobacterias (5.9% were positive) and parasite 4.5% (12.5% positive). Susceptibility test were performed by automatic methods (62.3%) followed by diffusion test (27.1%) and E-test (9.1%). A total of 5.6% of the susceptibility tests showed in vitro resistance to antibiotics. Fungi were identified in 108 isolates. Candida and Aspergillus were the most frequent genus (85.1% and 8.3%, respectively). Origins of the samples were: lower respiratory tract (32.4 %), genital tract (24.1 %), urine (10.2 %), blood (10.2 %) and skin (10.2 %). Twelve identification techniques were used, the most frequent being the morphological test (54.8%) and biochemical test (39.7%). Broken down by departments, 20.4% were sent from the ICU, 16.7% from surgery, 29.6% from medicine and 18.5% from primary care.

Discussion. Although the workload of the laboratories has been measured in this work, aspects such as specimen manipulation, clinical advice and research were not considered.

  

Key words: Laboratory. Fungi. Activity. Assistance. Organization.

Rev Esp Quimioter 2008;21(4):206-212 [pdf]  

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Rev Esp Quimioter 2008;21(3):198-202

Why not revisiting tinidazole as potential treatment of odontogenic infections?

F. Manso ,  M. S. Gamboa ,  M. J. Giménez ,  A. Bascones ,  M. L. Gómez-Lus ,  L. Aguilar 

  

Tinidazole is a 5-nitroimidazole initially introduced into clinical medicine in 1969 for the treatment of unicellular parasites. Tinidazole offers selective bactericidal activity, not influenced by the inoculum size, against anaerobic bacteria, that make it of theoretical interest against periodontopathogen infections. This article reviews the required characteristics of an antibiotic directed to odontogenic anaerobic infections, as well as the pharmacodynamic pitfalls of common antibiotic treatments. In addition the in vitro, pharmacokinetic and pharmacodynamic properties of tinidazole are reviewed, assessing the degree of its adhesion to the required characteristics, as well as identifying the gaps to be fulfilled prior to its use in this medical field. Tinidazole offers interesting characteristics making worthy investigations as a candidate for the treatment of anaerobic odontogenic infections.

 

Key words: Tinidazole. Odontogenic infections. Odontopathogens. Pharmacodynamia.

Rev Esp Quimioter 2008;21(3):198-202  [pdf] 

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Rev Esp Quimioter 2008;21(3):194-197

Antimicrobial drugs errors: the silent epidemic in patient safety

M. D. Menéndez Fraga ,  J. J. Corte García ,  M. Alonso Álvarez ,  M. Espín Fernández ,  J. Solano Jaurrieta. ,  F. Vázquez Valdés 

  

Introduction. Prescribed drugs and the mistakes in the administration to patient is the first cause of adverse events in the hospitals. The aim of this study has been to evaluate antimicrobial drug mistakes in one of our hospital wards in a two year period 2005 and 2006.

Methods. All the errors were reported through the National Health Service IR2 form (England) on a voluntary basis and classified by means of process, type of errors, their causes and contributory factors, as well as the severity. We analyzed the economic costs.    

Results. A 1.3% of the inpatients had an antimicrobial error in the administration to the patient (0.84 by 1,000 prescribing orders). Classified by processes, the administration (32.4%) and dispensation (44.1%) were the most frequent errors. By type of error: the erroneous medication (32.4%), the main root cause the human factors (58.8 %) and the contribution factor due to design of tasks (55.9 %). The 5.9% of errors were severe events, mainly in the group of the betalactamic drugs, and mainly by parenteral administration (50%).

Conclusions. Antimicrobial drug errors, frequent and sometimes severe, suppose a silent epidemic not being detected without the patient safety methodology. They represent a high cost for a hospital.

  

Key words: Medication errors. Antimicrobial drugs. Patient safety.

Rev Esp Quimioter 2008;21(3):194-197 [pdf]   

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Rev Esp Quimioter 2008;21(3):189-193

In vitro activities of colistin combinations against Pseudomonas aeruginosa isolated from the intensive care unit

F. López-Fabal ,  E. Culebras ,  I. Bonilla ,  M. Gómez ,  J. J. Picazo 

  

Introduction. As the number of multidrug-resistant strains of Pseudomonas aeruginosa has risen in the intensive care unit (ICU) of the San Carlos Clinic Hospital, 12 consecutive isolates from different patients were collected to determine the possibility of an epidemic outbreak caused by the spread of a single strain. We determined the antimicrobial susceptibility to the most common agents used in the treatment of infections caused by this bacteria. The results of susceptibility studies suggest that different strains of P. aeruginosa are responsible for the respiratory tract infections in ICU.

Methods. The clonal relationship between the isolates using was determined using BOX and ERIC primers by means of repetitive sequence-based polymerase chain reaction (rep-PCR). The in vitro activity of these strains against colistin, rifampicin, doxicycline and azythromycin was studied to determine in which cases the combination of colistin with any of the other three antibiotics was synergistic.

Results. Sensitivity studies point out the presence of several strains of P. aeruginosa as the causal agents of respiratory infections produced by this microorganism in the ICU. Combinations of colistin with doxycicline and colistin with azithromycin were synergistic for some isolates in the synergy studies. 

Discussion. Clonal studies reveal the presence of five different clones among our isolates. Therefore we can conclude that there was no outbreak of P. aeruginosa in the ICU. Synergistic activity of combinations of colistin plus azithromycin, colistin plus doxicycline and colistin plus rifampicin was less than expected and a high percentage of indifferent results was observed.    

Key words: P. aeruginosa. Synergistic activity. Colistin. Rep-PCR.

 

Rev Esp Quimioter 2008;21(3):189-193 [pdf]  

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Rev Esp Quimioter 2008;21(3):184-188

Comparison between Phoenix system and agar-based methods for antimicrobial susceptibility testing of Streptococcus spp

L. Martínez-Lamas ,  M. Treviño Castellano ,  P. A. Romero-Jung ,  B. J. Regueiro García 

  

Introduction. Antibiotic resistance is an emerging problem among streptococcal species, especially for severe infections. Automated diagnostic systems for antimicrobial susceptibility testing, such as BD Phoenix, is a recently available instruments that makes it possible to obtain results within 12 h.

Methods. Antimicrobial susceptibility testing results of the BD Phoenix system were compared to those obtained from Clinical Laboratory Standards Institute (CLSI) disk-diffusion method. Two-hundred different clinical isolates of streptococci were assayed: beta-hemolytic (n=65), viridans (n=87), S. penumoniae (n=48).

Results. Overall, there was categorical agreement greater than 96.7% (94.8% for beta-hemolytic and 97.9% for viridans group) in relationship to the disk-diffusion method. The minor error rates were less than 10% for all the antibiotics. The greatest percentage of serious errors corresponded to erythromycin and clindamycin within the beta-hemolytic group (14.7%). Overall percentage of very serious errors was less 0.5%. The results for penicillin in viridans streptococci and S. pneumoniae results showed 89.7% and 91.7% of categorical agreement, respectively, using the Etest as reference.

Conclusions. The automated BD Phoenix system is a very useful and effective diagnostic tool for quantitative testing of sensitivity to antibiotics in the streptococci group.

  

Key words: Streptococcus. Antimicrobial susceptibility testing. Phoenix. Disk-diffusion. ETest

Rev Esp Quimioter 2008;21(3):184-188 [pdf]      

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