Frequency Of Positive Cultures Research Articles

Time-Dependent Bacterial Contamination of a Surgical Suction Tip.

Background: No in vitro surgical study has evaluated the time-dependent contamination of surgical suction tips compared with controls. Our purpose was to determine the difference in suction tip bacterial contamination rates between suction-positive and suction-negative tips. Materials and Methods: A matched-pair analysis of the contamination of surgical suction tips over a six-hour period was performed in two clean operating rooms. One suction tip was connected to standard wall suction (suction-positive group), with a matched control tip not connected to wall suction (suction-negative group). At time zero and then at hourly intervals for six hours, the distal 3 cm of suction tips were removed, placed in nutrient broth for 48 hours, then plate cultured. One hundred tips were collected for each time interval. Results: Eighty-two of 700 (11.7%) suction tips had bacterial contamination. Sixty-three (18.0%) of 350 suction-positive tips were contaminated, with 19 (5.4%) of the 350 suction-negative tips contaminated (χ2 = 26.7, p < 0.001). Suction tip contamination was time-dependent with the first significant difference between groups occurring after two hours of continuous suction (χ2 = 4.0, p = 0.04). Contamination rate in the suction-positive group increased significantly after one hour compared with time-zero controls (χ2 = 7.1, p = 0.008). There was no significant difference in frequency of positive cultures over time in the suction-negative group compared with time-zero controls. Conclusions: This is the first controlled laboratory study suggesting a time-dependent increase in positive suction tip cultures. From our data, operating room staff should have an awareness that suction tips represent a potential source of bacterial concentration. We recommend that when not in use, suction tip valves be closed if this feature is available, that hosing be manipulated to cease suction when not needed, that suckers be disconnected from tubing, or that suckers be exchanged at frequent intervals. Doing so may reduce bacterial contamination on the suction tip.

191. Predictive Value of Procalcitonin across Disease States within an Inpatient Veteran Population

Abstract Background Procalcitonin (PCT) can be elevated with certain bacterial infections. Debate continues as to how to best use this biomarker to guide antibiotic use. The primary objective of this study was to evaluate the correlation of PCT levels and the presence of bacterial infection on admission in the total population and in different disease states. Methods This was a multicenter retrospective cross-sectional study of patients admitted with specified infectious diagnoses to two VA Medical Centers from 4/1/2019 to 7/1/2021. Patients were stratified into 4 cohorts for analysis; those with COVID-19, sepsis from respiratory source_(S-R), sepsis from non-respiratory source (S-NR), and respiratory source without sepsis (R). Electronic medical records were reviewed to collect the following: initial procalcitonin, cultures, SIRS criteria, comorbidities (CKD, ESRD, HF, immunosuppressed, surgery within the 7 days), and c-reactive protein. PCT elevation was defined as ≥0.25 ng/mL. The frequency of positive cultures within 72 hours was evaluated for patients with elevated and normal PCT levels to determine the diagnostic performance of PCT overall and for each cohort. Results 632 of 664 patients were evaluated in this study. PCT is elevated twice as often in the septic groups as compared to the non-septic groups (figure 1). Positive predictive value (PPV) varies from 27% to 63% as compared to negative predictive value (NPV) 53%-79% among the disease state groups (figure 2). Although small numbers, the NPV of PCT improves to 83% in patients with elevated temperature and white blood cells (WBC) (figure 3). Figure 1Figure 2Figure 3 Conclusion The findings that NPV of PCT appears to be better than PPV, support current recommendations against using this as a diagnostic tool, but rather as a tool to assist with antibiotic de-escalation. Further studies are necessary to confirm whether there are specific markers such as temperature or WBC which may improve the NPV. Our data suggests PCT is less helpful in identifying the presence or absence of bacterial infection in septic versus non-septic patients. Disclosures All Authors: No reported disclosures.

Evaluation of gallbladder microorganisms in patients undergoing cholecystectomy and its relationship with clinical and laboratory parameters

Introduction: Acute cholecystitis is one of the most common gallbladder diseases. Surgical operation is still the main treatment of biliary diseases, but there may be required a period of stabilization in the hospital before cholecystectomy. Infected bile in different studies has been reported from 50% to 75%. Therefore, identification of microbial mass followed by antibiotic treatment for this disease is important. Objectives: In this study, bacterial spectrum in patients undergoing cholecystectomy was evaluated based on clinical symptoms and laboratory parameters. Patients and Methods: In this prospective cross-sectional study, all patients requiring cholecystectomy were enrolled in the study. In the study, the data on age, gender, clinical signs of all patients and laboratory results and biliary liquid experiments were collected. Results: Fourteen cases including 13 cases of E. coli and a Staphylococcus strain had positive cultures. No significant correlation was detected between gender, fever, vomiting, tenderness right upper quadrant (RUQ), anorexia, jaundice, age group and microbial growth (P&gt;0.05). Moreover, no significant correlation between laboratory parameters such as white blood cell (WBC), total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, amylase and microbial growth was seen (P&gt;0.05). Conclusion: Bile culture was positive in 14% of patients undergoing cholecystectomy and E. coli was the predominant microorganism. Frequency of positive culture is low and has no relationship with demographic, clinical and laboratory factors and could not have a significant effect on the occurrence of postoperative complications; therefore, it seems that the administration of antibiotics before surgery is not necessary.

Evaluation of mare endometrial cytology using the novel cytotape technique

The cytobrush is considered the method of choice to obtain endometrial samples. Rigid brush fibers, however, may induce endometrial irritation and bleeding, or cell fragmentation, decreasing quality and diagnostic value of the samples. It was hypothesized that samples collected using a novel cytotape would provide sample smears of greater quality and less blood contamination than the cytobrush. Endometrial samples were collected with a cytotape and a cytobrush from ten mares without endometritis. Endometritis was then induced with artificial insemination, and samples were again collected 6 h after insemination. A cytology smear and bacterial culture were prepared from each sample. The collection methods and times were compared in terms of number and integrity of endometrial cells; number, integrity, and percentage of neutrophils; number of red blood cells, and number of colony-forming units. Frequency of positive cytology and culture was compared when there was use of each technique. The sensitivity, specificity, positive predictive value, and negative predictive value of cytology and culture for each technique was calculated using endometrial biopsy as the gold standard. While all samples had adequate and comparable cellularity and cell integrity, cytotape samples had less red blood cell contamination compared to cytobrush samples (P < 0.05). The number and percentage of PMNs, frequency of positive cytology diagnosis, number of colony-forming units and frequency of positive cultures did not differ between collection methods. In conclusion, the cytotape is a rapid, easy, and practical technique that can provide endometrial samples with similar diagnostic value to the cytobrush, but with less blood contamination.

Antimicrobial resistance increased over an 8-year period in Enterobacteriaceae cultured from canine urine samples.

The aims of the present study were to describe the prevalence of positive urinary bacterial culture in dogs, to identify the most commonly isolated microorganisms and to analyse changes in antimicrobial susceptibility patterns over time. A retrospective case series was performed using culture and susceptibility results from canine urine samples collected between January 2010 and December 2017. The presence or absence of infection, identity of the bacterium with heaviest growth, and susceptibility profile were recorded for each sample. Trends in the frequency of positive culture and antimicrobial resistance were assessed by Poisson regression modelling. Prevalence rate ratio and 95% confidence interval were reported for resistance to each antimicrobial. A positive urine culture was documented in 771 (22.5%) of 3420 samples. Escherichia coli was the most commonly isolated microorganism. There was no significant increase in the frequency of positive bacterial culture over the study period (prevalence rate ratio 0.98; 95% confidence interval: 0.92 to 1.0). Overall, there was an increase in antimicrobial resistance within Enterobacteriaceae from 5.2 to 35.6%. The prevalence of multidrug-resistant bacteria varied from year to year throughout the study period. However, the Poisson regression model identified a significant increase in the frequency of multidrug-resistant Enterobacteriaceae over this period, averaging approximately 22% per year (prevalence rate ratio 1.22, 95% confidence interval: 1.06 to 1.42). The significant increase in antimicrobial resistance observed in this study is concerning and may have implications for veterinary and public health. Appropriate measures, such as antibiotic stewardship programmes, should be implemented to address increasing antimicrobial resistance.

The Effect of Tracheal Fluid Culture Sampling Method and Culture Results on Antibiotic Use in Neonates

Abstract Objective As part of quality improvement effort to decrease antibiotic use for presumed pneumonia (PNA) in our neonatal intensive care unit, we introduced minibronchoalveolar lavage (mBAL) to obtain culture specimens. We evaluated the effect of tracheal sampling method and culture results on antibiotic use. Methods We performed a retrospective review of culture results of samples obtained by tracheal aspirates (TAs) and mBAL between January 2017 and April 2018. Noting the time cultures were obtained, we reviewed the records to determine if the patients met the Center for Disease Control and Prevention (CDC) criteria for PNA and evaluated culture results and antibiotic treatment practice. Fisher's exact and Mann–Whitney's tests when appropriate were used for the analysis. Results Thirty-five (35) mBAL (on 21 patients) and 42 TAs (on 39 patients) were done prior to antibiotic therapy. The tests were done at similar median day of life in both groups (mBAL 55 days and TA 62 days). The frequencies of positive culture were similar in both groups (mBAL 60% and TA 57%). At the time of obtaining the sample, more mBAL patients met the CDC criteria for PNA (mBAL 54% and TA 26%). Antibiotic days and duration of antibiotic treatment were significantly higher in the mBAL group compared with the TA group. In patient with no clinical PNA, antibiotic days were significantly higher in those with positive cultures (which more likely reflect colonizing microbes) than those with negative cultures and were also higher in the mBAL group than in the TA group. There was a significant increase in the frequency of positive cultures in patients with longer hospital stay. Conclusion Our results show that tracheal cultures on sick neonates with no clinical PNA and with long hospital stay might contribute to unnecessary antibiotic use regardless of the tracheal sampling method.

Ocular Surface Microbial Flora in Patients with Chronic Limbal Stem Cell Deficiency Undergoing Cultivated Oral Mucosal Epithelial Transplantation.

PURPOSE:The purpose of this study is to analyze the ocular surface microbial flora in patients with chronic limbal stem cell deficiency (LSCD) due to Stevens–Johnson Syndrome (SJS) and ocular chemical injury undergoing cultivated oral mucosal epithelial transplantation (COMET).METHODS:Patients of SJS and chemical injury who had bilateral total LSCD planned for COMET were studied. Conjunctival swab was taken before surgery. Parameters evaluated were organism cultured, sensitivity pattern, frequency of positive culture, and clinical impact on management strategy.RESULTS:Thirteen patients were included in which nine were males and four females. All patients had positive conjunctival swab culture. Most common organism isolated was Staphylococcus epidermidis, followed by Staphylococcus aureus and Pseudomonas aeruginosa. The staphylococcal species isolated were sensitive to all the conventional antibiotics while Pseudomonas cultured showed resistance to cefuroxime, ceftriaxone, and ceftazidime. Repeat conjunctival swab sent after a week of topical antibiotic therapy yielded positive culture of the same organism twice in 25% (3/12), thrice in 58.3% (7/12), and four times in 16.6% (2/12) of the patients. One patient had a polymicrobial flora with positive yield of S. aureus (thrice), S. epidermidis (twice), and P. aeruginosa (twice) in consecutive conjunctival swab culture in the absence of clinical infection. Two patients with persistent positive cultures had to undergo repeat oral mucosal harvesting as the transplantation of the cultivated explants had to be deferred.CONCLUSION:Ocular surface in LSCD patients yielded pathogenic organisms on culture. Poor ocular surface with absent tear film could be the contributing factors. It is important to perform the conjunctival swab culture before COMET surgery.

Frequency of MRSA Isolates in Mobile Phones, Ears and Hands of Healthcare Workers

Background: Mobile devices and hand of Healthcare Workers may contaminate with bacteria and become a source of infection. Objective: This study was conducted to identify the types of bacteria in mobile phones, ears, and hands of health workers (HCWs) in Kosti teaching hospital and to determine the frequency of MRSA among Staphylococcus auerus isolates from these specimens. Materials and Methods: This was a cross-sectional, hospital and laboratory based study, was carried out in Kosti Teaching Hospital. A total of 120 swab samples were collected from mobile phone, hand and ear of healthcare workers. All the swabs were cultured directly on blood agar, MacConkey agar and chocolate agar. Identification of isolates was did base on colonial appearance, Gram stain, and conventional biochemical tests. All Staphylococcus auerus isolates were subjected to antibiotics susceptibility testing using disc diffusion technique. Data were analyzed by statistical package for social sciences (SPSS) software version 17 and presented in form of tables. Results: The frequency of positive culture among mobile phone, ear, and hand swabs were were 95% (57/60), 100% (30/30) and 96.7% (29/30), respectively. The frequency of MRSA was 98.6%. Conclusions: Mobile phone, ear and hand of Healthcare Workers were the source of nosocomial infections. Good basic hygiene measures are extremely important, not only for hospital staff but also for patients and visitors, and it has a positive impact in infection control.

Influence of Handprint Culture Training on Compliance of Healthcare Workers with Hand Hygiene.

Objective We aimed to study the effect of visual observation of bacterial growth from handprints on healthcare workers' (HCWs) compliance with hand hygiene (HH). Settings Medical and postoperative cardiac surgery units. Design Prospective cohort study. Subject The study included 40 HCWs. Intervention Each HCW was interviewed on 3 separate occasions. The 1st interview was held to obtain a handprint culture before and after a session demonstrating the 7 steps of HH using alcohol-based hand rub, allowing comparison of results before and after HH. A 2nd interview was held 6 weeks later to obtain handprint culture after HH. A 3rd interview was held to obtain a handprint culture before HH. One month before implementation of handprint cultures and during the 12-week study period, monitoring of HCWs for compliance with HH was observed by 2 independent observers. Main Results There was a significant improvement in HH compliance following handprint culture interview (p < 0.001). The frequency of positive cultures, obtained from patients with suspected healthcare-associated infections, significantly declined (blood cultures: p = 0.001; wound cultures: p = 0,003; sputum cultures: p = 0.005). Conclusion The visual message of handprint bacterial growth before and after HH seems an effective method to improve HH compliance.

Pediatric Ventilator-Associated Infections: The Ventilator-Associated INfection Study.

Suspected ventilator-associated infection is the most common reason for antibiotics in the PICU. We sought to characterize the clinical variables associated with continuing antibiotics after initial evaluation for suspected ventilator-associated infection and to determine whether clinical variables or antibiotic treatment influenced outcomes. Prospective, observational cohort study conducted in 47 PICUs in the United States, Canada, and Australia. Two hundred twenty-nine pediatric patients ventilated more than 48 hours undergoing respiratory secretion cultures were enrolled as "suspected ventilator-associated infection" in a prospective cohort study, those receiving antibiotics of less than or equal to 3 days were categorized as "evaluation only," and greater than 3 days as "treated." Demographics, diagnoses, comorbidities, culture results, and clinical data were compared between evaluation only and treated subjects and between subjects with positive versus negative cultures. PICUs in 47 hospitals in the United States, Canada, and Australia. All patients undergoing respiratory secretion cultures during the 6 study periods. None. Treated subjects differed from evaluation-only subjects only in frequency of positive cultures (79% vs 36%; p < 0.0001). Subjects with positive cultures were more likely to have chronic lung disease, tracheostomy, and shorter PICU stay, but there were no differences in ventilator days or mortality. Outcomes were similar in subjects with positive or negative cultures irrespective of antibiotic treatment. Immunocompromise and higher Pediatric Logistic Organ Dysfunction scores were the only variables associated with mortality in the overall population, but treated subjects with endotracheal tubes had significantly lower mortality. Positive respiratory cultures were the primary determinant of continued antibiotic treatment in children with suspected ventilator-associated infection. Positive cultures were not associated with worse outcomes irrespective of antibiotic treatment although the lower mortality in treated subjects with endotracheal tubes is notable. The necessity of continuing antibiotics for a positive respiratory culture in suspected ventilator-associated infection requires further study.

Bronchoscopic Abnormalities in Pediatric Chronic Cough: A Case-Control Study

Background: Lower airway abnormalities, inflammation and bacterial infection are frequently described in children with chronic cough but its frequency in asymptomatic children is unknown. We report bronchoscopic abnormalities observed in children with chronic cough and in children undergoing fiberoptic bronchoscopy for causes other than chronic cough. Methods and findings: Retrospective case-control cohort study. The clinical records of children who had fiberoptic bronchoscopy for a history of chronic cough between 2008 and 2014 and of control children who required fiberoptic bronchoscopy for other causes were reviewed. Bronchoscopic findings and bronchoalveolar lavage results were assessed. Cases were 50 [27 female, median age 5.5 (0.5-12) years]. Their cough was wet in 37 (74%). Controls were 29 [12 female, median age 5.6 (0.5-14) years]. Airway malacia was observed in 25 cases (50%) vs 4 controls (14%) (p=0.001) and profuse secretions in 22 (44%) vs 6 (21%) (p = 0.03). When bronchoalveolar lavage was performed relevant organisms were isolated in 18 (45%) cases vs 4 (18%) controls (p=0.03). H influenzae (9), M catarrhalis (4) and S pneumonia (3) were seen only in cases. Polymerase chain reaction to viruses was positive in 13 (33%) cases vs 4 (14%) controls (p=0.04). Similar viruses were found in both: Rhinovirus and Adenovirus. Conclusions: Airway abnormalities were observed in seven out of ten cases the commonest one being airway malacia. It was associated with a higher frequency of positive cultures mostly for non typable H. influenzae and M. catarrhalis which were not isolated in controls. Similar viruses (Rhinovirus and Adenovirus) were found in both groups, although isolation was more frequent in cases.

Variations of Potentially Pathogenic Bacteria Found on the External Genitalia of Stallions During the Breeding Season

Potentially pathogenic bacteria such as, beta-hemolytic Streptococcus equi subspecies zooepidemicus, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia, are commonly isolated from cultures of the external genitalia of healthy stallions and can pose a risk to the fertility of stallions and mares. We hypothesized that there would be no difference in the frequency of cultures testing positive for potentially pathogenic bacteria throughout the breeding season and that when individual stallions cultured positive, they were not more likely to continue to culture positive. Nine Thoroughbred stallions, bred exclusively by live cover, were used. Samples for bacteriologic evaluation were taken from the prepuce and postejaculate urethra at a sampling interval of every 10th mare bred. All stallions were considered to be healthy and of sound breeding status as well as breeding a minimum of 20 mares during the season. The breeding season was divided into three different time periods, with February and March being early breeding season, April being midseason, and May and June being late breeding season. There was no difference in the frequency of positive cultures between the three separate time periods (P = .1677). However, a post hoc pairwise comparison revealed a tendency (P = .07) for more cultures to be positive at the end of the breeding season compared with the beginning of the season. Furthermore, the presence of a positive culture did not increase the incidence of positive cultures from the same stallion on subsequent collections (P = .1025). In conclusion, these results suggest a transient colonization of potentially pathogenic bacteria of the external genitalia of stallions.

GENDER FEATURES OF NEWLY DIAGNOSED INFILTRATIVE PULMONARY TUBERCULOSIS

Analysis of gender difference in presentation of newly diagnosed infiltrative pulmonary tuberculosis included data of 252 males and 147 females and showed that females develop the disease more frequently in childbearing age (20 to 29 years) and have more frequent contacts with TB patients. The ways to diagnose the disease, clinical manifestations, irregular fluorographic examination, and delayed seeking the aid were not related to gender. Despite more localized lung injury in females the frequency of positive culture was similar in females and males but multidrug resistance of M. tuberculosis was registered 1.6-fold more often in females. This could indicate higher risk of TB transmission from a woman with pulmonary TB to children owing to their close contact.

Atypical Mycobacterium Detection in Refractory Chronic Rhinosinusitis

Atypical mycobacterium (AM) involvement in refractory chronic rhinosinusitis (CRS) is sought by some surgeons with customary acid-fast bacilli cultures (AFBC) in the operating room (OR). We evaluate our experience with AM in CRS by describing (1) associated risk factors, (2) species identified, and (3) frequency of positive cultures in clinic versus OR. Case series with chart review. Tertiary rhinology practice. AFBC taken between 2005 and 2011 were identified from a microbiology laboratory database. Charts were reviewed for gender, age, medical history, risk factors for AM, pathogen types, and treatments, with statistical comparison using Pearson χ(2). The benefit of "targeted AFBC" for cases with high clinical suspicion was compared with "customary AFBC" in the OR. Thirty-seven patients were identified with AM, of which 10 had one or more risk factors for AM including foreign body (n = 4), non-HIV immune dysfunction (n = 4), and previous chemoradiation (n = 4). Six different AM species were identified: most frequently Mycobacterium abscessus (57.1%), followed by Mycobacterium avium-intracellulare complex (14.3%) and Mycobacterium chelonae (14.3%). "Targeted AFBC" from the outpatient setting were positive in 10 of 190 (5.3%) patients, whereas 10 of 373 (2.6%) patients of "customary AFBC" in the OR were positive (P = .12). Macrolide therapy was employed in 23 of 37 (62%) patients with AM-associated CRS but was not prescribed in patients with positive "customary AFBC" alone. AM-associated CRS is an uncommon condition that can occur in the absence of foreign body or overtly altered innate/adaptive immunity. Indications and efficacy of macrolide therapy, as well as the potential relationships between existence of AM in tap water, AM biofilms, and frequent use of nasal irrigations warrant further investigation in refractory CRS.

Atypical Mycobacterium Detection in Refractory Chronic Rhinosinusitis

Objective: Atypical mycobacterium (AM) involvement in refractory chronic rhinosinusitis (CRS) is sought by some surgeons with customary acid-fast bacilli cultures (AFBC) in the operating room (OR). We evaluate our experience with AM in CRS by describing: 1) associated risk factors, 2) species identified, and 3) frequency of positive cultures in clinic vs OR. Method: AFBC taken between 2005 and 2010 were identified from microbiology laboratory databases. Charts were reviewed for gender, age, medical history, risk factors for AM, pathogen types, and treatments with statistical comparison using PearsonX2. Benefit of “targeted AFBC” for cases with high clinical suspicion was compared with “customary AFBC” in OR. Results: Thirty-one patients were identified with AM, of which 10 had one or more risk factors for AM, including foreign body (n = 4), non-HIV immune dysfunction (n = 4), and previous chemo-radiation (n = 4). Six different AM species were identified: most frequently M abscessus (50%), followed by M avium-intracellulare complex (20%) and M chelonae (17%). “Targeted AFBC” from outpatient setting were positive in 10 out of 190 (5.3%), whereas 10 out of 393 (2.5%) of “customary AFBC” in OR were positive ( P = .09). Macrolide therapy was employed in 16 out of 31 (52%) patients with AM-associated CRS but was not prescribed in patients with positive “customary AFBC” alone. Conclusion: AM-associated CRS is an uncommon condition that can occur in the absence of foreign body or overtly altered innate/adaptive immunity. Management with macrolide therapy, as well as the potential relationships between existence of AM in tap water, AM biofilms, and frequent nasal irrigations, warrant further investigation in refractory CRS.

Effectiveness of Fluconazole for Suppressive Maintenance Therapy in Patients with RVVC: a Randomized Placebo-Controlled Study

Recurrent vulvovaginal candidiasis (RVVC) is seen in 5% of women with Candida vaginitis. Use of fluconazole as prophylactic treatment has been suggested for RVVC. The aim of the present study was to evaluate the efficacy of fluconazole suppressive therapy in RVVC patients, as a randomized, placebo-controlled, double-blind prophylactic study. Among the 330 women with acute symptomatic vulvovaginal candidiasis referred to Mirza-kouchak Khan gynecology hospital, 64 eligible subjects with RVVC were enrolled. Then, all of them were treated with fluconazole (150 mg orally every 3 days, for three doses). This was followed by microscopical and clinical examination. Next, patients were randomly divided into two groups. In the fluconazole group (n = 32), patients received fluconazole 150 mg, per week for 6 months and in the control group (n = 32) they received placebo. All the patients were revisited on a monthly basis and at the end of treatment, as well as 3 and 6 months after treatment. At the end of treatment, the frequency of positive culture in fluconazole group was significantly lower than the placebo group (25% vs. 62.5%, P = 0.05). Furthermore, the rate of clinical recurrence was significantly lower in the fluconazole group,with respect to the placebo group (18.8% vs. 50%, P = 0.017). However, following band 6 months after treatment, patients who received fluconazole maintenance therapy had a non-significant differences, compared to the placebo group, based on the rate of clinical recurrence or the frequency of positive cultures. Resistance to fluconazole (MIC ≥ 64) was comparable between groups. Despite the fact that fluconazole is well tolerated by the patients, suppressive treatment with fluconazole in RVVC patients had an insufficient effect on prevention from recurrence of clinical signs and the improvement of vaginal mycological status in long term (3-6 months after treatment).

Ability of Chemomechanical Preparation with Either Rotary Instruments or Self-adjusting File to Disinfect Oval-shaped Root Canals

Introduction Oval-shaped root canals might represent a great challenge for proper disinfection. This study compared the capability of a newly developed instrument, the self-adjusting file (SAF), and rotary nickel-titanium (NiTi) instrumentation to eliminate Enterococcus faecalis populations from long oval root canals of extracted human teeth. As a secondary purpose, the ability of a modification in sampling technique to recover bacteria lodged in recesses of oval canals was evaluated. Methods Long oval canals from mandibular incisors and maxillary second premolars were infected with E. faecalis (ATCC 29212) for 30 days and then randomly distributed into 2 experimental groups. In group 1, canals were prepared up to a 40/04 rotary BioRaCe instrument by using irrigation with NaviTip needles; in group 2, canals were prepared by using the SAF system with continuous irrigation. NaOCl and ethylenediaminetetraacetic acid were used as irrigants. Bacteriologic samples were taken before (S1) and after preparation (S2a and S2b). Results Reduction in the bacterial populations was highly significant in both groups ( P < .001). Preparation of long oval canals with the SAF was significantly more effective than rotary NiTi instrumentation in reducing intracanal E. faecalis counts ( P = .01). Frequency of positive cultures in S2 samples was 11 of 20 (55%) for rotary instrumentation and 4 of 20 (20%) for SAF instrumentation ( P = .048). S2b samples (modified method) yielded more positive samples than S2a (12/40 vs 5/40), but this difference reached no statistical significance ( P > .05). Conclusions The SAF system was significantly more effective than rotary NiTi instrumentation used with syringe/needle irrigation in disinfecting long oval root canals in vitro. A modified sampling technique might be necessary for oval canals.

The Liver Plays a Major Role in Clearance and Destruction of Blood Trypomastigotes in Trypanosoma cruzi Chronically Infected Mice

Intravenous challenge with Trypanosoma cruzi can be used to investigate the process and consequences of blood parasite clearance in experimental Chagas disease. One hour after intravenous challenge of chronically infected mice with 5×106 trypomastigotes, the liver constituted a major site of parasite accumulation, as revealed by PCR. Intact parasites and/or parasite remnants were visualized at this time point scattered in the liver parenchyma. Moreover, at this time, many of liver-cleared parasites were viable, as estimated by the frequency of positive cultures, which considerably diminished after 48 h. Following clearance, the number of infiltrating cells in the hepatic tissue notably increased: initially (at 24 h) as diffuse infiltrates affecting the whole parenchyma, and at 48 h, in the form of large focal infiltrates in both the parenchyma and perivascular spaces. Phenotypic characterization of liver-infiltrating cells 24 h after challenge revealed an increase in Mac1+, CD8+ and CD4+ cells, followed by natural killer (NK) cells. As evidence that liver-infiltrating CD4+ and CD8+ cells were activated, increased frequencies of CD69+CD8+, CD69+CD4+ and CD25+CD122+CD4+ cells were observed at 24 and 48 h after challenge, and of CD25−CD122+CD4+ cells at 48 h. The major role of CD4+ cells in liver protection was suggested by data showing a very high frequency of interferon (IFN)-γ-producing CD4+ cells 24 h after challenge. In contrast, liver CD8+ cells produced little IFN-γ, even though they showed an enhanced potential for secreting this cytokine, as revealed by in vitro T cell receptor (TCR) stimulation. Confirming the effectiveness of the liver immune response in blood parasite control during the chronic phase of infection, no live parasites were detected in this organ 7 days after challenge.

Pulmonary infection in mild variant cystic fibrosis: Implications for care

Background Disease phenotype in cystic fibrosis (CF) shows considerable heterogeneity. Atypical or mild mutations in the CFTR gene have been linked to late-onset pulmonary disease; however, few reports document the condition of the airway in infants and young children with apparent “mild” disease. Prognosis is uncertain in this group of patients and this, in turn, has led to inconsistency in management. Our initial experience of pulmonary infection in children with mild variant CF prompted a more detailed review of clinical outcome. Methods A retrospective cohort study was carried out comparing frequency of bacterial isolates and clinical outcomes in eleven compound heterozygotes for ΔF508 and a second mild mutation, mainly R117H, with a matched group of ΔF508 homozygotes. Results Staphylococcus aureus was isolated in 8 of the 11 patients with mild variant disease and Pseudomonas aeruginosa found in 7 (64%), although the frequency of positive cultures was significantly less (2.8/year) than the ΔF508 homozygotes (6.1/year, p < 0.05). Shwachman scores (median + range) were significantly higher in patients with mild mutations — 94, 74–92 vs. 88, 77–91; p < 0.005); there was also a small but significant difference in chest radiograph (Chrispin–Norman) scores (median + range) (mild 5.1, 4–9, vs. severe 5.8, 3–10; p 0.04). There was little difference in lung function in terms of FEV 1 (median + range) between the two groups (% predicted, mild 86.5, 68–87 vs. severe 76.0, 65–88; p 0.5). Conclusions Most patients with mild variant CF will have bacterial isolates from airway cultures requiring antibiotic therapy three to four times a year. Infection with both S. aureus and P. aeruginosa is common. Anti-staphylococcal prophylaxis for the first two years should be considered.

Fluoroquinolone therapy in Mycobacterium chelonae keratitis after lamellar keratectomy

To characterize a rabbit model of Mycobacterium chelonae keratitis after lamellar keratectomy and assess the effectiveness of fluoroquinolone therapy. University Laboratory, University of California, Irvine, California, USA. Twenty-eight New Zealand white rabbits had unilateral lamellar keratectomy with placement of 2.5 x 10(5) colony-forming units of log-phase M chelonae under each flap. Eyes (7 per group) were randomized and treated with sterile balanced salt solution, gatifloxacin 0.3%, ciprofloxacin 0.3%, or levofloxacin 0.5% 4 times daily. Two masked observers examined all eyes on days 2, 5, and 7 and weekly for 4 weeks. Severity of disease and bacterial culture results were the main outcomes measured. The means and standard deviations were calculated, and differences between the groups were statistically analyzed. All eyes developed clinical disease. At the time the rabbits were killed, eyes treated with balanced salt solution, ciprofloxacin, levofloxacin, and gatifloxacin were culture positive in 6 (85.7%), 7 (100%), 6 (85.7%), and 3 (42.9%) of 7 eyes per group, respectively. Frequency of positive culture and the severity of clinical disease in gatifloxacin-treated eyes were significantly less (P < .05) than in the other groups combined. The rabbit model of M chelonae keratitis was successfully developed in our study. A fourth-generation quinolone (gatifloxacin) showed the best performance among the fluoroquinolones tested in our experimental approach. The fourth-generation fluoroquinolone, gatifloxacin, could be effectively used for the treatment of mycobacterial keratitis.