Semiquantitative Culture Research Articles

Detection of mixed microbial biofilms on central venous catheters removed from Intensive care Unit Patients

Central venous catheters from intensive care unit patients were subjected to microbiological methods (semiquantitative culture) and scanning electron microscopy in order to assess microbial attachment and correlate it with blood cultures. During the period of the survey, 59 patients with inserted central venous catheters were studied. The type of catheter used was nontunneled, noncuffed, single lumen, made of polyurethane. Blood samples for cultures were collected at the moment of catheter removal. Data on the patient's age, gender, catheter insertion site, and duration of catheterization were also obtained. From 63 catheters tips analysed, 30 (47.6%) showed microbial colonization. Infection proved to be more prevalent in 26 (41.3%) patients with catheters inserted via subclavia vein than in 2 (3.2%) inserted via the jugular vein. Infection was observed more frequently in catheters which were kept in place more than seven days. A. baumannii, Citrobacter freundii, E. aerogenes, P. aeruginosa and S. saprohyticus were isolated as causal agents of catheter-related bloodstream infections. The antimicrobial agent with greater in vitro activity against Gram-negative bacteria was imipenen and against Gram-positive were vancomycin, cefepime, penicillin, rifampin and tetracycline. The SEM analyses revealed biofilms on surfaces of all the catheters examined.

Apport diagnostique de l'écouvillonnage de la zone d'insertion cutanée dans l'exploration des infections liées aux cathéters veineux centraux dans un service de réanimation médicochirurgicale

Objective. – To evaluate the predictive value of pericatheter skin cultures in detecting catheter-related infections in critically-ill patients. Study design. – Prospective study. Patients and methods. – Over a 5 months period (from August 1 st 2001 to December 31 2001), 500 patients were hospitalised, and 108 central venous catheters were prospectively examined. For each catheter, blood cultures, pericatheter skin cultures and semiquantitative culture of the catheter tip were performed. Results. – The median duration of catheterization was 8 days (interquartile: 8 days). Catheter was removed because of suspected infection in 54 cases (50%). Systemic catheter-related infection was found in 12 cases (11%) and the responsible organism was a gram-negative rod in 11 cases (92%). The negative predictive values of pericatheter skin cultures in the diagnosis of catheter-related infections and in case of suspected catheter-related infection were 89 and 86%, respectively. Conclusion. – These results indicate that the pericatheter skin cultures are not an effective procedure for the conservative diagnosis of catheter-related infections and that the skin-insertion wound is not the major source of catheter-contamination in our unit.

Acridine orange leukocyte cytospin test for central venous catheter–related bloodstream infection: A pediatric experience

The aim of this study was to evaluate the acridine orange leukocyte cytospin (AOLC) test for the rapid diagnosis of septicemia caused by central venous catheters (CVCs), without removing the catheter, in a pediatric intensive care unit population. Twenty-six patients admitted in the pediatric intensive care unit of Azienda Ospedaliera “Ospedali Riuniti di Bergamo”, Italy, were prospectively evaluated for CVC-related infection. Blood for culture was taken from all patients. Quantitative endoluminal cultures of the removed catheter tip by Cleri's technique and semiquantitative superficial cultures of the hub were performed. Gram staining and an AOLC smear were done according to Kite's technique. Four Staphylococcus CVC-related bloodstream infections were identified. CVC colonization was detected in 8 patients. Four had septicemia ( Enterococcus faecalis, Escherichia coli, Klebsiella oxytoca, Candida glabrata) without CVC involvement. However, Gram staining and the AOLC test were negative in all cases. We conclude that cytocentrifugation and acridine orange staining of blood withdrawn by Kite's method from an in situ catheter, although simple, quick, and inexpensive, did not aid diagnosis in this pediatric population.

Meta-Analysis: Methods for Diagnosing Intravascular Device–Related Bloodstream Infection

No consensus exists on the best methods for diagnosis of intravascular device (IVD)-related bloodstream infection. To identify the most accurate methods for diagnosis of IVD-related bloodstream infection. 51 English-language studies published from 1966 to 31 July 2004. Studies of diagnostic tests for IVD-related bloodstream infection that described a reference standard and provided sufficient data to calculate sensitivity and specificity. Study quality, diagnostic tests examined, patient characteristics, prevalence, sensitivity, and specificity. Pooled sensitivity and specificity were calculated for 8 diagnostic methods. Summary measures of accuracy were Q* (the upper leftmost point on the summary receiver-operating characteristic curve) and mean D (a log odds ratio). Subgroup analyses were used to assess heterogeneity. Overall, the most accurate test was paired quantitative blood culture (Q* = 0.94 [95% CI, 0.88 to 1.0]), followed by IVD-drawn quantitative [corrected] blood culture (Q* = 0.89 [CI, 0.79 to 0.99]) and the acridine orange leukocyte cytospin test (Q* = 0.89 [CI, 0.79 to 0.91]). The most accurate catheter segment culture test was quantitative culture (Q* = 0.87 [CI, 0.81 to 0.93]), followed by semi-quantitative culture (Q* = 0.84 [CI, 0.80 to 0.88]). Significant heterogeneity in pooled sensitivity and specificity was observed across all test categories. The limited number of studies of some of the diagnostic methods precludes precise estimates of accuracy. Paired quantitative blood culture is the most accurate test for diagnosis of IVD-related bloodstream infection. However, most other methods studied showed acceptable sensitivity and specificity (both >0.75) and negative predictive value (>99%). The positive predictive value of all tests increased greatly with high pretest clinical probability. Catheters should not be cultured routinely but rather only if IVD-related bloodstream infection is suspected clinically.

Differential quantitative blood cultures for the diagnosis of catheter-related bloodstream infections associated with short- and long-term catheters: A prospective study

We prospectively evaluated the value of two levels of differential quantitative blood culture (DQBC) ratio (≥2:1 or ≥5:1) in diagnosing catheter-related bloodstream infections (CRBSIs) in patients with malignancy that have short-term and long-term central venous catheters (CVCs) (<30 and ≥30 days of placement). Diagnosis of CRBSIs was based on results of semiquantitative cultures of removed catheters. For short-term CVCs a 5:1 or greater DQBC ratio had an 18% sensitivity, 67% specificity, 18% positive predictive value (PPV) and 67% negative predictive value (NPV), whereas a 2:1 or greater cut-off point for the DQBC was associated with a 45% sensitivity, 48% specificity, 26% PPV, and 68% NPV for the diagnosis of CRBSIs. For long-term CVCs, a cut-off point of 5:1 or greater of the DQBC had an 81% sensitivity, 40% specificity, 36% PPV, and 83% NPV for the diagnosis of CRBSIa, whereas a 2:1 or greater cut-off point had a 90% sensitivity, 30% specificity, 35% PPV, and 88% NPV for the diagnosis of CRBSIs. In conclusion, DQBCs are not diagnostic of CRBSIs for short-term CVCs. In long-term CVCs, DQBCs at 2:1 or greater or 5:1 or greater are sensitive but associated with low specificity and positive predictive value.

Bacterial Colonization and Home Mechanical Ventilation: Prevalence and Risk Factors

To investigate the prevalence of bacterial contamination of ventilators and colonization of patients, the bacteria implicated, and predisposing factors in noninvasive home ventilation. Forty patients on a home noninvasive ventilation program (mean [SD] age: 63.1 [12] years; time on ventilation: 30.7 [25] months; daily use: 8.1 [2] hours) were enrolled in this descriptive cross-sectional study. Microbiological samples for semiquantitative cultures were swabbed from the ventilator (mask and tubing) and the nostrils. A questionnaire was completed on the underlying disease, time on the ventilation program, type of ventilator, presence of a humidifier, and attention to ventilator cleanliness and maintenance. We defined "colonization" as the presence of microorganisms in the nostrils without evidence of a host immune response, and "contamination" as the presence of surface microorganisms (on tubing or the nasal mask). Potentially pathogenic bacteria were isolated from 6 ventilators (15%) and the nasal swabs of 10 patients (25%). Staphylococcus aureus was the most frequently isolated one (in 5 ventilators and 6 patients--contamination coinciding with colonization in 3 cases). Other potentially pathogenic bacteria isolated were Proteus species (from the nostrils of 2 patients) and an unidentified gram-negative bacillus from the ventilator. On analysis by underlying disease, 60% of the patients with obesity had been colonized. No other findings of note were obtained for other diseases. Contamination and colonization correlated with attention to cleanliness and maintenance of the ventilator but not with type of ventilator, time on the ventilation program, or use of a humidifier. Home mechanical ventilators are a potential source of nasal colonization. The most frequently encountered microorganism was S. aureus. The degree of ventilator cleaning and disinfection seems to affect contamination; thus it is necessary to impress on patients the need for adequate maintenance of their ventilators.

Candida parapsilosis bloodstream infection in pediatric oncology patients: results of an epidemiologic investigation.

To investigate an outbreak of Candida parapsilosis bloodstream infections (BSIs) involving three patients admitted to a pediatric oncology unit between April and June 2002. After the third case was documented, cultures were performed of the hands of all medical and paramedical staff members in the pediatric oncology unit and of environmental surfaces in the rooms occupied by the three patients. Electrophoretic karyotyping with pulsed-field gel electrophoresis and arbitrarily primed polymerase chain reaction were used to assess the genetic relatedness among C. parapsilosis isolates. The three cases of C. parapsilosis BSI were diagnosed based on blood cultures performed during a 38-day period. Evidence of prior C parapsilosis colonization of the gastrointestinal tract was present in only the first case. Each patient had an indwelling central venous catheter (CVC), which was promptly removed, and semiquantitative catheter tip cultures also revealed C. parapsilosis. None of the 30 environmental cultures performed was positive for C. parapsilosis, but the fungus was isolated from the hands of 6 of the 20 nurses tested. Both molecular typing methods revealed identical DNA fingerprinting patterns for all 13 patient isolates (7 from blood, 3 from CVC tips, and 3 from the gastrointestinal tract) and for 5 of the 6 recovered from the nurses' hands. These findings suggest the possibility of cross-infection with a single C. parapsilosis strain that was transmitted (probably during CVC dressing changes) by nurses whose hands were colonized with it. The role of previous gastrointestinal colonization in the first case cannot be excluded.

Prevention of catheter-related bloodstream infection in critically ill patients using a disinfectable, needle-free connector: A randomized controlled trial

Objective The aim of this study was to assess the efficacy of a disinfectable, needle-free connector in the prophylaxis of catheter-related bloodstream infection. Methods A randomized controlled trial was performed in a polyvalent intensive care unit. Patients who needed multilumen central venous catheters were randomly assigned to a study or a control group. All catheters were inserted and manipulated according to the Centers for Disease Control and Prevention (CDC) recommendations. Study group patients were equipped with catheters with disinfectable, needle-free connectors whereas control group patients were equipped with catheters with 3-way stopcocks. Two peripheral blood cultures and a semiquantitative culture of the catheter tip were performed on removal of the catheter. Results The study included 243 patients, with a total of 278 central venous catheters. The catheters' mean insertion duration was 9.9 days. Both groups were comparable regarding patient and catheter characteristics. Incidence rate of catheter-related bloodstream infection was 0.7 per 1000 days of catheter use in the study group, compared with 5.0 per 1000 days of catheter use in the control group ( P = .03). Conclusions To add a disinfectable, needle-free connector to the CDC recommendations reduces the incidence of catheter-related bloodstream infection in critically ill patients with central venous catheters.

Mutans streptococci, lactobacilli in saliva and acidity from organisms in dental plaque: changes after restorative treatment.

The effect of restorative dental treatment was evaluated on mutans streptococci and lactobacilli in saliva, as well as acid production by plaque bacteria. We used semiquantitative culture kits at time points up to 6 months following treatment. Changes in eating habits and oral hygiene during the study period were ruled out using a questionnaire. Mutans streptococci, lactobacilli, and acidity all had decreased significantly at 1 week after treatment. Acidity often was the first variable to return to pretreatment levels, while abundant at 6 than 3 months. Lactobacilli showed the most durable response to treatment. Restorative treatment achieves import temporary decreases in caries-associated bacteria, especially lactobacilli, without influence from potentially relevant behavioral changes. In addition, follow up examinations at relatively long intervals at least 3 month would appear most effective for dental health management.

DIAGNOSIS OF BACTERIAL VAGINOSIS IN A RURAL SETUP : COMPARISON OF CLINICAL ALGORITHM, SMEAR SCORING AND CULTURE BY SEMIQUANTITATIVE TECHNIQUE

This study was undertaken to estimate the prevalence of bacterial vaginosis (BV) and other sexually transmitted infections (STIs) in a rural set up and compare the smear scoring system to that of culture by semiquantitative technique. A total of 505 married women, who were in sexually active age group of 15-44 years, were selected from three different villages. High vaginal swabs, endocervical swabs, vaginal discharge and blood were collected and processed in the laboratory. Overall prevalence of 29% reproductive tract infection was detected. Endogenous infection was commonly observed (27.92%), and very low prevalence of STIs (Trichomonas 1.18%, Syphilis 0%, Gonorrhea 0%) was detected. Diagnosis of BV was possible in 104 (20.5%) women by smear alone and 88 (17.42%) women by semiquantitative culture.

Frequency and colonization rate of intravascular catheters

Clinical signs are not sufficiently reliable for establishing diagnosis of intravascular catheter-related infection. Therefore, microbiological confirmation, based on the culture of the catheter tip after its removal, is necessary in diagnosing the infection. The aim of this study was to determine the frequency and the degree of microbial colonization of intravascular catheters (IVK), and the risk for the onset of sepsis, by using qualitative, semiquantitative (roll plate) and quantitative (vortexing) catheter culture techniques. During the period April 2001-December 2002, 289 intravascular catheters were cultured. A total of 284 microorganisms were isolated from 217 (75%) culture-positive catheters. The frequency of isolation of some organisms was the following: coagulase-negative staphylococci (CNS) 41%, Staphylococcus aureus 19%, Enterococci spp 6%, other gram-positive microorganisms 9%, gram-negative microorganisms 21%, and fungi 4%. In 35 catheters, cultures were polymicrobial; two microorganisms were found in 25 cultures and three were found to be in 10 cultures. There were 122 (46%) intravascular catheters, which were found significantly colonized. A high rate of positivity and a high rate of S. aureus isolates and gram-negative bacteria indicate the need of establishing the exact microbiological diagnosis of these infections, and the rigorous undertaking of adequate control and preventive measures.

Diagnosis of ventilator-associated pneumonia

This review examines the various techniques used to diagnose ventilator-associated pneumonia. The ideal diagnostic test not only helps the clinician to recognize whether pneumonia is present, but also to influence clinical outcome. Several studies have suggested that the clinical pulmonary infection score can be used to detect the onset of ventilator associated pneumonia. Serial clinical pulmonary infection scores have also been useful in helping to decide when to stop therapy. Semiquantitative culture methods have been used for nonbronchoscopic and bronchoscopic samples. Adequate initial empiric therapy for those organisms identified in these samples has been associated with improved survival. This supports the use of these culture techniques to diagnose patients with ventilator-associated pneumonia. Diagnostic testing for ventilator-associated pneumonia can identify those patients at risk for a poor clinical outcome.

Evaluation of a new chromogenic medium, Uriselect 4, for the isolation and identification of urinary tract pathogens

Aims: To compare the performance of a new chromogenic medium, Uriselect 4, with cystine lactose electrolyte deficient (CLED) agar and an established chromogenic agar, CPS ID 2 medium, for detection...

Fungal contamination of elementary schools: a new environmental hazard

Sensitivity to fungi is a significant cause of allergic diseases, and prolonged indoor exposure to fungi is a growing health concern. This study evaluates the health effects of mold-contaminated schools on students and teachers. A discussion of the effectiveness of current methods for evaluating these schools, with a focus on the importance of using total mold spore counts, is also provided. Two Connecticut public schools were tested using multiple air quality testing methods, with the standard for a healthy indoor environment being total mold spore counts lower than 1,000 spores/m3. The health impact of the mold exposure at each school was evaluated using the validated Rhinitis Outcomes Questionnaire. The testing of the first school found indoor mold counts ranging from 6,000 to 50,000 spores/m3. Eighty-five of the students and teachers reported significant allergic symptoms to the school nurse. This school is currently being demolished. More than 2 years after the exposure ended, a number of occupants of the school continue to have elevated symptoms compared with before their exposure to the school. The testing of the second school revealed total mold spore counts ranging between 2,000 and 9,000 spores/m3, qualifying it an unhealthy environment in need of immediate remediation. Students reported significant allergic symptoms from exposure to certain rooms that are currently being remediated. Because of the negative impact on health that indoor mold exposure has, particularly in atopic patients, schools should be routinely tested for fungal contamination. Total mold spore counts should be performed using volumetric air sampling such as the Allergenco MK-3 (Allergenco, San Antonio, TX) because testing air quality via semiquantitative culture sampling alone does not give a true reflection of the extent of fungal contamination. Finally, the standard for a healthy indoor environment should be defined as having <1,000 spores/m3.

Screening for Significant Bacteriuria in Patients with Upper Tract Calculi Using Dipstick Urine Analysis

Screening for Significant Bacteriuria in Patients with Upper Tract Calculi Using Dipstick Urine Analysis

Eficacia de dos métodos semiautomáticos para la exclusión de bacteriuria

A quick and reliable method for detecting bacteriuria would allow to exclude the presence of microorganisms in the urine on the same day the sample is obtained.Objectives. Two semiautomatic methods have been evaluated for bacteriuria screening, taking the semiquantitative culture as reference method. A prospective study of urine samples from patients suspected of having a urinary infection was designed. One method is based on bioluminescence that detects the presence of ATP liberated by the bacterial cell (Utiscreen-Coral Biomedical). The other semiautomatic method uses a nephelometry technique (Uro-quick). The results of each semiautomatic method were compared with the semiquantitative culture. Samples presenting counts > 104 UFC/ml of one or two microorganisms were considered as having urinary-tract infection (equivalent to significative bacteriuria). Cultures with counts < 5,000 UFC/ml or containing three or more microorganisms were classified as non-representative of significant bacteriuria. The nephelometric system allows to obtain results at two different times. Samples were divided into two groups to compare both situations. 1,090 urine samples, received consecutively, were considered. In the case of the bioluminescence system, the study was prolonged to 1,565 samples. The values obtained were: a) bioluminescence: general data, sensibilitiy (S) 5 94.4%; especificity (E) 5 72.8%; positive predictive value (PPV) 5 46.2% and negative predictive value (NPV) 5 98.2%; hospitalized patients only, S 5 97.5%; E 5 77.3%; PPV 5 61.2% and NPV 5 98.8%; and b) nephelometry: 195 min, S 5 96.7%; E 5 88.8%; PPV 5 67.9% and NPV 5 99.1%; 235 min, S 5 95.5%; E 5 81.0%; PPV 5 58.7% and NPV 5 98.4%. A negative predictive value from both methods under these conditions would allow them to be used in medical centers for the exclusion of bacteriuria.

Prevention and Management of Long-Term Catheter Related Infections in Cancer Patients

Long-term central venous catheters (CVC) are necessary in the care of cancer patients. However, catheter-related bloodstream infection (CRBSI) is commonly associated with serious complications resulting in considerable morbidity and mortality. The diagnosis of CRBSI frequently requires catheter removal to confirm the diagnosis by either quantitative or semiquantitative catheter culture method. Differential time to positivity, whereby a nonquantitative blood culture drawn from the CVC that becomes positive at least 2 hr earlier than the peripheral blood culture, is a new method for the diagnosis of CRBSI without removing the catheter. Prevention of CRBSI may be accomplished with the use of strict infection control measures, antimicrobial-impregnated catheters, and antibiotic-lock technique, as well as other methods. Once infection develops, management of long-term CRBSI is dictated by the type of organism, the severity of the infection, and availability of other venous access sites. If the infection is caused by Staphylococcus aureus, gram-negative bacilli, or Candida, the catheter should be removed and systemic antimicrobial therapy given for 10–14 days or longer in cases of complicated or deep-seated infection. In some cases, where there is no other venous access site, the catheter can remain in place, but a combination of systemic antimicrobials and antibiotic-lock therapy should be used.

Pneumonia after cardiac surgery is predictable by tracheal aspirates but cannot be prevented by prolonged antibiotic prophylaxis

Background. The purpose of this study was to assess the value of tracheal aspirate as a predictor of pneumonia after coronary artery bypass grafting and to evaluate the efficacy of prolonged perioperative antibiotic prophylaxis. Methods. Tracheal aspirates of 500 patients undergoing coronary artery bypass grafting were taken immediately after intubation and analyzed for microorganisms by Gram stain and semiquantitative microbiologic cultures. All patients received 2 g ceftriaxone as a single-dose perioperative antibiotic prophylaxis before operation. Results of Gram stains were available before the patients were transferred to the intensive care unit. After the results were known, both groups of patients (positive Gram stain, group 1; negative Gram stain, group 2) were randomly assigned to either conventional antibiotic prophylaxis (A), consisting of ceftriaxone 2 g on postoperative day 1, or prolonged antibiotic prophylaxis (B), with ticarcillin + clavulanic acid 3 × 5.2 g during 72 hours. Results. From 500 patients, 91 had a positive Gram stain whereas 409 had a negative one. The incidence of pneumonia was significantly higher in patients with preoperative positive tracheal aspirates (15.3%) than in patients with a negative one (3.6%; p < 0.01). However, prolonged prophylaxis did not reduce the rate of postoperative pneumonia, which was as high as 13% in untreated positive patients versus 17% in treated positive patients, and 2% in untreated negative patients versus 4% in treated patients. In patients who had pneumonia, there was a high correlation between the microorganisms found in preoperative aspirates and those observed when aspirates were repeated (100% correlation in patients with conventional antibiotic prophylaxis and 87% in those with prolonged prophylaxis). Conclusions. Early postoperative pneumonia (<7 days) is most likely caused by microorganisms that colonize the respiratory tract before operation. The risk of pulmonary infection after coronary artery bypass grafting can be predicted from the preoperative tracheal aspirates. Prolonged perioperative antibiotic prophylaxis has no efficacy in reducing the incidence of pulmonary infections.

Resolution of infectious parameters after antimicrobial therapy in patients with ventilator-associated pneumonia.

Although recommended durations of antimicrobial therapy for ventilator-associated pneumonia (VAP) range from 7 to 21 d, these are not based on prospective studies and little is known about the resolution of symptoms after start of antibiotics. Resolution of these symptoms was investigated in 27 patients. VAP was diagnosed on clinical, radiographic, and microbiological criteria, including quantitative cultures of bronchoalveolar lavage. All patients received appropriate antibiotic therapy. Highest temperatures, leukocyte counts, Pa(O(2))/FI(O(2)) ratios, and semiquantitative cultures of endotracheal aspirates were recorded from start of therapy until Day 14. Resolution was defined as the first day that these parameters fulfilled the following definition: temperature < or = 38 degrees C, leukocytes < or = 10 x 10(9)/L, Pa(O(2))/FI(O(2)) ratio > or = 25 kPa, and no or +1 of bacterial growth of etiologic pathogens in cultures of endotracheal aspirate. VAP was caused by Enterobacteriaceae (n = 14), P. aeruginosa (n = 7), S. aureus (n = 6), H. influenzae (n = 3), and S. pneumoniae (n = 1). H. influenzae and S. pneumoniae were eradicated from tracheal aspirates, whereas Enterobacteriaceae, S. aureus, and P. aeruginosa persisted, despite in vitro susceptibility to antibiotics administered. Significant improvements were observed for all clinical parameters, most apparently within the first 6 d after start of antibiotics. Newly acquired colonization, especially with P. aeruginosa and Enterobacteriaceae, occurred in the second week of therapy. Six patients developed a recurrent episode of VAP, four of them with P. aeruginosa. Clinical responses to therapy for VAP occur within the first 6 d of therapy, endotracheal colonization with Gram-negative bacteria persists despite susceptibility to therapy, and acquired colonization usually occurs in the second week of therapy and frequently precedes a recurrent episode.

Catheter-Related Infections: Diagnosis and Intravascular Treatment

The diagnosis of catheter-related infections relies on the presence of clinical manifestations of infection and the evidence of colonization of the catheter tip by bacteria, mycobacteria or fungi. The reference method to confirm the latter requires the withdrawal of the catheter for culturing, which frequently turns out to be inconvenient, unnecessary and costly. New methods try to avoid these inconveniences and to assess the presence of tip colonization without withdrawal. One of these methods uses quantitative blood cultures with a jump (>5) in colony counts between blood obtained from the catheter lumen and simultaneously from a peripheral vein. It has a high sensitivity (>80%) and specificity (94%-100%) but is cumbersome and requires both an easy backflow of blood in the catheter and the existence of bacteremia. Cytocentrifugation and acridine orange staining of blood withdrawn from an infected catheter lumen has a sensitivity and a specificity of over 90% for the diagnosis of tip colonization.“Superficial cultures” consist in the semiquantitative culture of the hub, of the skin surrounding the catheter entrance and of the first (1 cm) subcutaneous portion of the catheter after swabbing. Sensitivity of this method is >90% and specificity is >80%, and positive and negative predictive values for catheters (considering together those with and without clinical data of infection) are 66% and 97%, respectively.Endoluminal brushing has turned out to be an impractical and unreliable procedure, at least in our experience.New methods based on the speed of bacterial growth to detectable levels of microorganisms in conventional blood cultures are a new and interesting way of assessing catheter-related infections. Besides, as use of antimicrobial-coated catheters becomes more prevalent, the existing definitions of catheter colonization and catheter-related infection may need to be modified, because such coatings may lead to false-negative culture results.Many catheter infections, diagnosed without catheter withdrawal, can be handled nowadays with the so-called “antibiotic lock-in technique”, which consists in locking the infected catheter lumen with a solution containing antibiotics. A high proportion of infected catheters, mainly those with coagulase-neg-ative staphylococci, can be maintained in place and sterilized with this technique, including catheters in patients with therapeutic failure after receiving conventional intravenous antibiotic therapy.New diagnostic and therapeutic techniques may avoid the unnecessary withdrawal of thousands of efficient, difficult to replace and expensive intravascular lines.