Meropenem-Resistant Achromobacter xylosoxidans, Subspecies Denitrificans Bacteremia in a Patient With Stage IV Adenocarcinoma of the Lung.

Achromobacter xylosoxidans,subspecies denitrificans is a rare Gram-negative bacillus that causes health care associated infections in immunocompromised hosts. Carbapenems and anti-pseudomonal penicillins are listed as suitable empiric therapy in the literature. Herein, we report a case of a 77-year-old male with stage IV adenocarcinoma of the lung who presented with and was improving from Salmonella javiana enterocolitis, only to subsequently develop A. xylosoxidans,subspecies denitrificans bacteremia that was resistant to both meropenem and piperacillin-tazobactam. With empiric antibiotic coverage falling short of microbial clearance, timelyin vitrosusceptibility testing and prompt infectious disease consultation are of the utmost importance for treatment.

Glove and gown effects on intraoperative bacterial contamination.

OBJECTIVE: Experiments were performed to determine the risk of bacterial contamination associated with changing outer gloves and using disposable spunlace paper versus reusable cloth gowns. BACKGROUND: Despite decades of research, there remains a lack of consensus regarding certain aspects of optimal aseptic technique including outer glove exchange while double-gloving and surgical gown type selection. METHODS: In an initial glove study, 102 surgical team members were randomized to exchange or retain outer gloves 1 hour into clean orthopedic procedures; cultures were obtained 15 minutes later from the palm of the surgeon's dominant gloved hand and from the surgical gown sleeve. Surgical gown type selection was recorded. A laboratory strike-through study investigating bacterial transmission through cloth and paper gowns was performed with coagulase-negative staphylococci. In a follow-up glove study, 251 surgical team members, all wearing paper gowns, were randomized as in the first glove study. RESULTS: Glove study 1 revealed 4-fold higher levels of baseline bacterial contamination (31% vs 7%) on the sleeve of surgical team members wearing cloth gowns than those using paper gowns [odds ratio (95% confidence interval): 4.64 (1.72-12.53); P = 0.0016]. The bacterial strike-through study revealed that 26 of 27 cloth gowns allowed bacterial transmission through the material compared with 0 of 27 paper gowns (P < 0.001). In glove study 2, surgeons retaining outer gloves 1 hour into the case had a subsequent positive glove contamination rate of 23% compared with 13% among surgeons exchanging their original outer glove [odds ratio (95% confidence interval): 1.97 (1.02-3.80); P = 0.0419]. CONCLUSIONS: Paper gowns demonstrated less bacterial transmission in the laboratory and lower rates of contamination in the operating room. Disposable paper gowns are recommended for all surgical cases, especially those involving implants, because of the heightened risk of infection. Outer glove exchange just before handling implant materials is also recommended to minimize intraoperative contamination.

Stability and compatibility of antimicrobial lock solutions.

PURPOSE: Published stability and compatibility data on a growing array of solutions used for antimicrobial lock therapy (ALT) are reviewed. SUMMARY: ALT involves the instillation of a highly concentrated antimicrobial, often in combination with an anticoagulant, into a central venous catheter (CVC) lumen; this technique is often used for prophylaxis after CVC insertion or as an adjunctive treatment in cases of central line-associated bloodstream infection (CLABSI) if catheter removal is not feasible. Optimal selection of stable and compatible antimicrobials and additives can maximize catheter dwell times, streamline pharmacy compounding practices, and help ensure patient safety. Of 98 articles on ALT solutions identified in a literature search, 17 met the prespecified criteria for the use of validated stability and compatibility methodology. Antimicrobials active against common CLABSI pathogens that may be appropriate for ALT include cefazolin, cefotaxime, ceftazidime, ciprofloxacin, daptomycin, gentamicin, linezolid, telavancin, ticarcillin-clavulanic acid, and vancomycin; validated data demonstrate the stability of these agents in solution with heparin or nonheparin anticoagulants over 72-96 hours or longer. Other antifungal agents and antiinfectives (e.g., ethyl alcohol) have been used in specific patients and ALT situations. The prolonged stability of several antimicrobial-additive combinations may allow for extended dwell times and less frequent lock solution exchanges. CONCLUSION: Pharmacists' knowledge of diverse combinations of antimicrobial agents and additives in lock solutions, including several shown to be stable and compatible for extended periods, can help expand and optimize the use of ALT in both treatment and prophylactic modalities.

Diagnosing and reporting of central line-associated bloodstream infections.

BACKGROUND: The diagnosis of central line-associated bloodstream infections (CLABSIs) is often controversial, and existing guidelines differ in important ways. OBJECTIVE: To determine both the range of practices involved in obtaining blood culture samples and how central line-associated infections are diagnosed and to obtain members' opinions regarding the process of designating bloodstream infections as publicly reportable CLABSIs. DESIGN: Electronic and paper 11-question survey of infectious-diseases physician members of the Infectious Diseases Society of America Emerging Infections Network (IDSA EIN). PARTICIPANTS: All 1,364 IDSA EIN members were invited to participate. RESULTS: 692 (51%) members responded; 52% of respondents with adult practices reported that more than half of the blood culture samples for intensive care unit (ICU) patients with central lines were drawn through existing lines. A sizable majority of respondents used time to positivity, differential time to positivity when paired blood cultures are used, and quantitative culture of catheter tips when diagnosing CLABSI or determining the source of that bacteremia. When determining whether a bacteremia met the reportable CLABSI definition, a majority used a decision method that involved clinical judgment. CONCLUSIONS: Our survey documents a strong preference for drawing 1 set of blood culture samples from a peripheral line and 1 from the central line when evaluating fever in an ICU patient, as recommended by IDSA guidelines and in contrast to current Centers for Disease Control and Prevention recommendations. Our data show substantial variability when infectious-diseases physicians were asked to determine whether bloodstream infections were primary bacteremias, and therefore subject to public reporting by National Healthcare Safety Network guidelines, or secondary bacteremias, which are not reportable.

Recognition and prevention of nosocomial vascular device and related bloodstream infections in the intensive care unit.

Central venous catheters have become a mainstay in the care of critically ill patients but, unfortunately, are associated with a significant risk of bloodstream infections. There are 80,000 catheter-related bloodstream infections that occur annually in the United States, with a high human and financial cost. This paper reviews the main tools for prevention and diagnosis of central venous catheter-related bloodstream infections in the intensive care unit. We discuss specific aspects of prevention, including education, hand hygiene, sterile technique, skin cleansing, choice of catheter site, antimicrobial-impregnated catheters, catheter site dressings, antibiotic lock solutions, anticoagulation, catheter changes, and needleless connection devices. An analysis of studies evaluating the use of catheter "bundles" is also included. Diagnostic methods discussed include how to obtain blood cultures, when to culture catheter tips, how to interpret culture results, and the best methods for diagnosis.

Wide variability in the use of antimicrobial lock therapy and prophylaxis among infectious diseases consultants.

We surveyed infectious diseases physicians to determine their practice patterns with regard to both antimicrobial lock prophylaxis and antimicrobial lock therapy. Antimicrobial lock prophylaxis is relatively uncommon; only 19% of infectious diseases physicians reported using it at least once. Although antimicrobial lock therapy is more commonly used, we found a significant variation in practice patterns.

Effects of antibiotic-impregnated external ventricular drains on bacterial culture results: an in vitro analysis.

OBJECT: Treatment of ventriculoperitoneal shunt infections frequently requires placement of an external ventricular drain (EVD). Surveillance specimens obtained from antibiotic-impregnated (AI) EVDs may be less likely to demonstrate bacterial growth, potentially resulting in undertreatment of an infection. The purpose of this study was to assess whether AI EVDs had any significant effect on bacterial culture results compared with nonantibiotic-impregnated (NAI) EVDs. METHODS: In vitro assays were performed using AI EVDs containing minocycline and rifampin (VentriClear II, Medtronic) and NAI EVD controls (Bioglide, Medtronic). The presence of antibiotics was evaluated via capillary electrophoresis of sterile saline drawn from AI and NAI EVDs after predefined incubation intervals. Antimicrobial activity was assessed by evaluating zones of inhibition created by the catheter aspirates on plates inoculated with a quality control strain of Staphylococcus epidermidis (American Type Culture Collection strain 12228). To determine the effects of cultures drawn through AI compared with NAI EVDs, the quality control strain was then incubated within 4 new AI and 4 new NAI EVDs for predefined intervals before being plated on culture media. Spread and streak plate culture results from each type of catheter were compared at each time interval. RESULTS: Capillary electrophoresis showed that more minocycline than rifampin was eluted from the AI EVDs. Sterile saline samples incubated within the AI EVDs demonstrated zones of growth inhibition when placed on plates of S. epidermidis at all time intervals tested. No zones of inhibition were noted on NAI EVD control plates. When a standardized inoculum of S. epidermidis was drawn through AI and NAI EVDs, antimicrobial effects were observed after incubation in the AI EVD group only. Colony counting demonstrated that significantly fewer colonies resulted from samples drawn through AI compared with NAI EVDs at the multiple time intervals. Similarly, streak plating yielded a statistically significant number of false-negative results from AI compared with NAI EVDs at 2 time intervals. CONCLUSIONS: The findings in the current study indicate that the risk of a false-negative culture result may be increased when a CSF sample is drawn through an AI catheter. In the management of a known shunt infection, a false-negative result from an EVD culture specimen may lead to an inappropriately short duration of antibiotic therapy. These data have significant clinical implications, particularly given the widespread use of AI drains and the current high rates of shunt reinfection after EVD use worldwide.

Health care-associated bloodstream infections associated with negative- or positive-pressure or displacement mechanical valve needleless connectors.

BACKGROUND: Health care-associated, central venous catheter-related bloodstream infections (HA-BSIs) are a major cause of morbidity and mortality. Needleless connectors (NCs) are an important component of the intravenous system. NCs initially were introduced to reduce health care worker needlestick injuries, yet some of these NCs may increase HA-BSI risk. METHODS: We compared HA-BSI rates on wards or intensive care units (ICUs) at 5 hospitals that had converted from split septum (SS) connectors or needles to mechanical valve needleless connectors (MV-NCs). The hospitals (16 ICUs, 1 entire hospital, and 1 oncology unit; 3 hospitals were located in the United States, and 2 were located in Australia) had conducted HA-BSI surveillance using Centers for Disease Control and Prevention definitions during use of both NCs. HA-BSI rates and prevention practices were compared during the pre-MV period, MV period, and post-MV period. RESULTS: The HA-BSI rate increased in all ICUs and wards when SS-NCs were replaced by MV-NCs. In the 16 ICUs, the HA-BSI rate increased significantly when SS-NCs or needles were replaced by MV-NCs (6.15 vs 9.49 BSIs per 1000 central venous catheter [CVC]-days; relative risk, 1.54; 95% confidence interval, 1.37-1.74; P < .001). The 14 ICUs that switched back to SS-NCs had significant reductions in their BSI rates (9.49 vs 5.77 BSIs per 1000 CVC-days; relative risk, 1.65; 95% confidence interval, 1.38-1.96; p < .001). BSI infection prevention strategies were similar in the pre-MV and MV periods. CONCLUSIONS: We found strong evidence that MV-NCs were associated with increased HA-BSI rates, despite similar BSI surveillance, definitions, and prevention strategies. Hospital personnel should monitor their HA-BSI rates and, if they are elevated, examine the role of newer technologies, such as MV-NCs.

Surgical site infection as a surrogate marker of physician impairment.

Our report details an implant-associated outbreak of surgical site infections related to the adverse effects of treatment for hepatitis C virus infection administered to surgeon X. During the 12-month period of this outbreak, 14 (9.5%) of 148 of surgeon X's patients developed a surgical site infection, a rate of SSI that was 8-fold higher than the rate during the 14-month baseline period or the 14-month follow-up period (P = .001), and higher than the rate among peer surgeons (P = .02).

Activity of novel antibiotic lock solutions in a model against isolates of catheter-related bloodstream infections.

BACKGROUND: Catheter-related bloodstream infections (CRBSIs) are a primary concern in patients with indwelling central venous catheters (CVCs). Instillation of an antibiotic lock solution may serve as an adjunctive therapy. OBJECTIVE: To evaluate the efficacy of novel antibiotic-anticoagulant lock solutions using an in vitro model of CVC infection. METHODS: The following lock solutions were evaluated: daptomycin 1 mg/mL (reconstituted with lactated Ringer's [LR]) plus heparin 5000 units/mL, tigecycline 0.5 mg/mL plus ethylenediaminetetraacetate (EDTA) 30 mg/mL, gentamicin 5 mg/mL plus EDTA 30 mg/mL, cefazolin 5 mg/mL plus heparin 5000 units/mL, and phosphate-buffered NaCl 0.9% as the control solution. Analysis was performed on Hickman catheter segments inoculated with the following organisms: methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Staphylococcus epidermidis, and Pseudomonas aeruginosa. The catheters were incubated in the candidate lock solutions for 0, 2, 4, and 24 hours. Student's t-tests were conducted to evaluate reduction in log(10) colony-forming units/milliliter (cfu/mL) of individual lock solutions compared with the control solution. For each organism, analysis of variance and Student's t-tests were performed to determine whether differences existed among the lock solutions. RESULTS: Gentamicin plus EDTA (G+EDTA) and tigecycline plus EDTA (Ti+EDTA) resulted in significant reductions (p < 0.05) of log(10) cfu/mL at 24 hours for all organisms tested. Daptomycin, reconstituted in LR, plus heparin (D+LR+H) demonstrated potent activity against all staphylococcal species (p < 0.05). With respect to MRSA, G+EDTA displayed significantly better activity than Ti+EDTA and cefazolin plus heparin (p < 0.05), but there was no significant difference compared with D+LR+H. No antagonism was noted with the addition of anticoagulants to the solutions. CONCLUSIONS: Gentamicin, tigecycline, and daptomycin in combination with anticoagulants as lock solutions displayed potent activity against common pathogens responsible for CRBSIs. Each of these lock solutions deserves strong consideration for study in a clinical trial. Further data on compatibility and stability of these solutions are needed before routine clinical use can be recommended.

Role of ethylene diamine tetra-acetic acid (EDTA) in catheter lock solutions: EDTA enhances the antifungal activity of amphotericin B lipid complex against Candida embedded in biofilm.

Ethylene diamine tetra-acetic acid (EDTA) is an anticoagulant with antibiofilm-enhancing activity. We therefore used an in vitro biofilm model to determine the activity of amphotericin B lipid complex (ABLC) with or without EDTA against Candida embedded in biofilm on silicone disk surfaces. Clinical blood isolates from cancer patients infected with Candida albicans or Candida parapsilosis were used. Silicone disks were colonised with C. albicans or C. parapsilosis and were sequentially incubated in plasma and then in Mueller-Hinton broth containing 10(5) colony-forming units of each organism. All tests were performed in triplicate. The disks were subsequently placed and incubated for 6h and 8h in solutions containing ABLC alone, EDTA alone, ABLC+EDTA or broth (control). Disks were then removed, sonicated and colony counts were determined. ABLC+EDTA (30 mg/mL) was significantly more effective than ABLC, EDTA and control against C. parapsilosis at 6h (P < or = 0.01) and against C. albicans at 8h (P < or = 0.04). In patients with catheter-related candidaemia when catheter removal is not feasible, the combination of ABLC+EDTA may be considered for antifungal catheter lock solution as part of a catheter salvage therapy.

Preventing the airborne spread of Staphylococcus aureus by persons with the common cold: effect of surgical scrubs, gowns, and masks.

OBJECTIVE: Transmission of Staphylococcus aureus via air may play an important role in healthcare settings. This study investigates the impact of barrier precautions on the spread of airborne S. aureus by volunteers with experimentally induced rhinovirus infection (ie, the common cold). DESIGN: Prospective nonrandomized study. SETTING: Wake Forest University School of Medicine (Winston-Salem, NC).Participants. A convenience sample of 10 individuals with nasal S. aureus carriage selected from 593 students screened for carriage. INTERVENTION: Airborne S. aureus dispersal was studied in the 10 participants under the following clothing conditions: street clothes, surgical scrubs, surgical scrubs and a gown, and the latter plus a face mask. After a 4-day baseline period, volunteers were exposed to a rhinovirus, and their clinical course was followed for 12 days. Daily swabs of nasal specimens, pharynx specimens, and skin specimens were obtained for quantitative culture, and cold symptoms were documented. Data were analyzed by random-effects negative binomial models. RESULTS: All participants developed a common cold. Incidence rate ratios (IRRs) indicated that, compared with airborne levels of S. aureus during sessions in which street clothes were worn, airborne levels decreased by 75% when surgical scrubs were worn (P<.001), by 80% when scrubs and a surgical gown were worn (P<.001), and by 82% when scrubs, a gown, and a face mask were worn (P<.001). The addition of a mask to the surgical scrubs and gown did not reduce the airborne dispersal significantly (IRR, 0.92; P>.05). Male volunteers shed twice as much S. aureus as females (incidence rate ratio, 2.04; P=.013). The cold did not alter the efficacy of the barrier precautions. CONCLUSIONS: Scrubs reduced the spread of airborne S. aureus, independent of the presence of a rhinovirus-induced cold. Airborne dispersal of S. aureus during sessions in which participants wore surgical scrubs was not significantly different from that during sessions in which gowns and gowns plus masks were also worn.

"Gesundheit!" sneezing, common colds, allergies, and Staphylococcus aureus dispersion.

BACKGROUND: Staphylococcus aureus is among the most important pathogens in today's hospital setting. METHODS: The effects of sneezing on the airborne dispersal of S. aureus and other bacteria were assessed in 11 healthy nasal S. aureus carriers with experimentally induced rhinovirus colds. Airborne dispersal was studied by volumetric air sampling in 2 chamber sessions with and without histamine-induced sneezing. After 2 days of preexposure measurements, volunteers were inoculated with a rhinovirus and monitored for 14 days. Daily quantitative nasal- and skin-culture samples for bacteria and nasal-culture samples for rhinovirus were obtained, cold symptoms were assessed, and volunteer activities were recorded during sessions. RESULTS: All participants developed a cold. Sneezing caused a 4.7-fold increase in the airborne dispersal of S. aureus, a 1.4-fold increase in coagulase-negative staphylococci (CoNS), and a 3.9-fold increase in other bacteria (P < .001). An additional 2.83 colony forming units (cfu) of S. aureus/m3/min, 3.24 cfu of CoNS/m3/min, and 474.61 cfu of other bacteria/m3/min were released per sneeze. Rhinovirus exposure did not change the frequency of sneezing or airborne dispersal. Having respiratory allergies increased the spread of S. aureus by 3.8-fold during sneezing sessions (P < .001). CONCLUSION: Nasal S. aureus carriers disperse a significant amount of S. aureus into the air by sneezing. Experimental colds do not alter bacterial dispersal, but respiratory allergies multiply the effect of dispersing S. aureus.

Comparative in vitro efficacies of various catheter lock solutions.

MEDTA (minocycline-edetate calcium disodium), taurolidine (2%)-polyvinylpyrolidine (5%) (T/PVP), and ethanol as potential catheter lock solutions have a unique mechanism of action, broad-spectrum activity, and anticoagulant properties. Traditional lock solutions minocycline (M), rifampin (R), ciprofloxacin (C), and vancomycin, except pharmacologic concentrations of C and R and of M and R, were less effective than MEDTA and T/PVP.

A randomized, controlled trial of a new vascular catheter flush solution (minocycline-EDTA) in temporary hemodialysis access.

BACKGROUND AND OBJECTIVE: We previously demonstrated that minocycline-EDTA was efficacious at preventing catheter-related bloodstream infections (BSIs) in three patients with recurrent infections. This study compared heparin with minocycline-EDTA as flush solutions used among dialysis patients with central venous catheters, a high-risk group for catheter-related BSI. METHODS: Patients were enrolled within 72 hours of catheter insertion and randomized to receive heparin or minocycline-EDTA as a flush after each dialysis session. Each syringe containing flush solution was wrapped in orange plastic to conceal the type of solution it contained. Patients were observed for evidence of infection and catheter thrombosis. After catheters were removed, cultures were performed to determine whether microbial colonization had occurred. RESULTS: During a 14-month period, 60 patients were enrolled (30 in each group). The two groups had similar demographics and underlying diseases. Catheter survival at 90 days was 83% for the minocycline-EDTA group versus 66% for the heparin group (P = .07). Significant catheter colonization, a surrogate measure of catheter-related infection, was significantly more frequent in the heparin group (9 of 14 vs 1 of 11; P = .005). There was only one catheter-related bacteremia and it occurred in the heparin group. CONCLUSIONS: When compared with heparin, minocycline-EDTA had a better 90-day catheter survival (P = .07) and a decreased rate of catheter colonization. This pilot study warrants a larger prospective, randomized trial.

Dispersal of Staphylococcus aureus into the air associated with a rhinovirus infection.

OBJECTIVE: To determine whether healthy adult nasal carriers of Staphylococcus aureus can disperse S. aureus into the air after rhinovirus infection. DESIGN: We investigated the "cloud" phenomenon among adult nasal carriers of S. aureus experimentally infected with a rhinovirus. Eleven volunteers were studied for 16 days in an airtight chamber wearing street clothes, sterile garb, or sterile garb plus surgical mask; rhinovirus inoculation occurred on day 2. Daily quantitative air, nasal, and skin cultures for S. aureus; cold symptom assessment; and nasal rhinovirus cultures were performed. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Wake Forest University undergraduate or graduate students who had persistent nasal carriage of S. aureus for 4 or 8 weeks. RESULTS: After rhinovirus inoculation, dispersal of S. aureus into the air increased 2-fold with peak increases up to 34-fold. Independent predictors of S. aureus dispersal included the time period after rhinovirus infection and wearing street clothes (P < .05). Wearing barrier garb but not a mask decreased dispersal of S. aureus into the air (P < .05). CONCLUSION: Virus-induced dispersal of S. aureus into the air may have an important role in the transmission of S. aureus and other bacteria.