Seroprevalence and risk factors of antibodies against Coxiella burnetii among dog owners in southwestern Québec, Canada

Coxiella burnetii is a zoonotic agent responsible for human Q fever, a potentially severe disease that can lead to persistent infection. This cross-sectional study aimed to estimate the seroprevalence to C. burnetii antibodies and its association with potential risk factors in the human population of five regions of Québec, Canada. A serum bank comprising sera from 474 dog owners was screened by an enzyme-linked immunosorbent assay followed by confirmation of positive or equivocal sera by an indirect immunofluorescence assay. Observed seroprevalences of 1.2% (95% confidence interval (CI): 0.0–6.6), 2.6% (95% CI: 0.5–7.4) and 5.9% (95% CI: 3.4–9.6) were estimated in the regions of Montréal, Lanaudière and Montérégie, respectively, which all included at least 83 samples. Having lived or worked on a small ruminant farm (prevalence odds ratio (POR) = 5.4; 95% CI: 1.6–17.7) and being a veterinarian or veterinary student (POR = 6.1; 95% CI: 1.6–24.0) were significantly associated with C. burnetii seropositivity. Antibodies against C. burnetii were detected in the human population of Québec. Although seropositivity to this agent was associated with occupational contact with domestic animals, antibodies were also detected in people with no reported professional exposure. No associations with ruminant farm proximity were identified.

Intuitive wireless control of a robotic arm for people living with an upper body disability

Assistive Technologies (ATs) also called extrinsic enablers are useful tools for people living with various disabilities. The key points when designing such useful devices not only concern their intended goal, but also the most suitable human-machine interface (HMI) that should be provided to users. This paper describes the design of a highly intuitive wireless controller for people living with upper body disabilities with a residual or complete control of their neck and their shoulders. Tested with JACO, a six-degree-of-freedom (6-DOF) assistive robotic arm with 3 flexible fingers on its end-effector, the system described in this article is made of low-cost commercial off-the-shelf components and allows a full emulation of JACO's standard controller, a 3 axis joystick with 7 user buttons. To do so, three nine-degree-of-freedom (9-DOF) inertial measurement units (IMUs) are connected to a microcontroller and help measuring the user's head and shoulders position, using a complementary filter approach. The results are then transmitted to a base-station via a 2.4-GHz low-power wireless transceiver and interpreted by the control algorithm running on a PC host. A dedicated software interface allows the user to quickly calibrate the controller, and translates the information into suitable commands for JACO. The proposed controller is thoroughly described, from the electronic design to implemented algorithms and user interfaces. Its performance and future improvements are discussed as well.

Cefotaxime, desacetyl-cefotaxime, and bactericidal activity in spontaneous bacterial peritonitis

We have prospectively studied 13 episodes of spontaneous bacterial peritonitis (SBP) in 12 patients treated with cefotaxime (CTX) 2 g intravenously every 8 h (mean duration, 5.3 days). Ascitic fluid was inoculated at the bedside. The cultures were done before, during (day 3 after CTX initiation), and 48-72 h (mean, 56 h) after the end of therapy. All SBP episodes were monomicrobial. During treatment, the concentrations of CTX and desacetyl-cefotaxime (d-CTX) in ascitic fluid were high in all 13 SBP episodes, and d-CTX was still present in 6 patients who had residual ascitic bactericidal titer (ABT) activity after the last dose of CTX. ABTs were >/=1:128 during CTX therapy in 12 episodes and were measurable in 7 patients after the last dose. All patients were cured. The present study provides scientific rationale to the clinical studies that suggest treating SBP episodes with lower doses of antibiotics and shorter treatment duration.

Management of intra-abdominal infections. The case for intraoperative cultures and comprehensive broad-spectrum antibiotic coverage. The Canadian Intra-abdominal Infection Study Group

OBJECTIVE

To test the hypothesis that comprehensive broad-spectrum empirical antimicrobial therapy is superior to limited-spectrum empirical antimicrobial therapy in intra-abdominal infections.

DESIGN

Prospective, randomized, double-blinded study.

SETTING

University-affiliated hospitals in Canada.

PATIENTS

Two hundred thirteen patients with intra-abdominal infections and planned operative or percutaneous drainage.

INTERVENTION

Limited-spectrum empirical antimicrobial therapy consisted of cefoxitin sodium, 2 g, intravenously, every 6 hours (n = 109). Comprehensive broad-spectrum empirical antimicrobial therapy consisted of a combination of imipenem and cilastatin sodium, 500 mg, intravenously, every 6 hours (n = 104).

MAIN OUTCOME MEASURES

Failure to cure the intra-abdominal infection (persistence of infection or death).

RESULTS

Of initial isolates, 98% were sensitive to imipenem plus cilastin sodium compared with 72% for cefoxitin. No difference was found in the failure rate between treatment groups. Among various reasons for failure (including technical), 12 of 80 patients in the limited-spectrum empirical antimicrobial therapy group had resistant organisms at a second intervention compared with 1 of 74 in the comprehensive broad-spectrum empirical antimicrobial therapy group (P < .003, chi 2). One death in the limited-spectrum empirical antimicrobial therapy group was due to autopsy-proved disseminated Pseudomonas aeruginosa (blood, peritoneum, lung, and pleural fluid) that was resistant to cefoxitin, and the other was associated with peritonitis due to cefoxitin-resistant Enterobacter cloacae. One death in the comprehensive broad-spectrum empirical antimicrobial therapy group was associated with peritonitis from Clostridium perfringens that was sensitive to imipenem plus cilastin sodium, and the other was associated with peritonitis from Pseudomonas aeruginosa that was resistant to imipenem plus cilastin sodium.

CONCLUSION

Treatment failure of intra-abdominal infection may be due, in part, to the presence of resistant pathogens at the site of infection. Therefore, routine culture of these sites seems worthwhile and empirical therapy should be as comprehensive as possible and should cover all potential pathogens.

Pneumococcal resistance to antimicrobial agents in the province of Québec, Canada

The serogroup/serotypes (SGTs) and antimicrobial susceptibilities to 10 antimicrobial agents of 110 clinical strains of Streptococcus pneumoniae were determined. Strains intermediately resistant or highly resistant to penicillin G (80 of 110) belonged predominantly to SGTs 23 (45.0%), 19 (13.7%), 6 (10.0%), 9 (6.2%), and 14 (3.7%). The MICs of all cephalosporins, tetracycline, trimethoprim-sulfamethoxazole, and chloramphenicol increased along with the MICs of penicillin G. However, erythromycin resistance and clindamycin resistance were observed more frequently among the intermediately penicillin-resistant strains. Multiple resistance was observed for 32 strains, of which 25 were highly resistant to penicillin G and belong to SGT 23F. All strains were susceptible to vancomycin.

Longitudinal study of susceptibilities of species of the Bacteroides fragilis group to five antimicrobial agents in three medical centers

A total of 579 clinical isolates of the Bacteroides fragilis group collected from three Canadian hospitals were tested for susceptibility to five antimicrobial agents by using an agar dilution method. During the 4-year survey, isolates from intra-abdominal infections were collected from the following sites: abdominal abscesses (48%), peritoneal fluid (39%), blood (10%), and bile (3%). B. fragilis was the most prevalent species (35.4%), followed by B. thetaiotaomicron (19.2%), B. ovatus (15.9%), and B. vulgatus (11%). No metronidazole- or imipenem-resistant strains were found during the survey. Resistance profiles varied among the different species tested: 7.8, 2.9, and 7.3% of B. fragilis strains (n = 205) and 68.1, 17.2, and 9.4% of non-B. fragilis strains (n = 373) were resistant to cefotetan, cefoxitin, and clindamycin, respectively. B. fragilis and B. vulgatus demonstrated lower resistance rates than B. thetaiotaomicron, B. ovatus, B. distasonis, and B. caccae. During the study, rates of resistance to cefotetan and clindamycin fluctuated but rates of resistance to cefoxitin increased, particularly at one center. These data indicate a need to determine the susceptibility patterns of the B. fragilis group periodically at each hospital.

[Comparative efficacy of antibiotic prophylaxis using cefoxitin in one or in three doses in cesarean section]

To compare the effectiveness of three doses and of a single dose of cefoxitin, a second-generation cephalosporin, in preventing infection after nonelective cesarean section, we carried out a prospective study in 255 women who underwent the procedure between March 1983 and February 1985. The rate of postoperative infection was 7% in the group that received three doses and 8% in the one-dose group. The sensitivity and specificity of perioperative cultures were low. The rate of asymptomatic bacteriuria was high, at 20%, but few symptomatic urinary tract infections were found. Routine antibiotic prophylaxis with a single dose is suggested for all nonelective cesarean sections.

Comparison of agar disk diffusion, microdilution broth, and agar dilution for testing antimicrobial susceptibility of coagulase-negative staphylococci

A collection of 120 oxacillin-susceptible and 120 oxacillin-resistant coagulase-negative staphylococci (CNS) from six tertiary care hospital laboratories were tested by agar disk diffusion, three microdilution broth systems (Sensititre, Dynatech, and Alpkem), and the Vitek AutoMicrobic system for comparison with reference agar dilution results. The antimicrobial agents tested were oxacillin, cefazolin, cefotaxime, cefuroxime, cefamandole, fusidic acid, rifampin, and vancomycin. Incubation was at 30 or 35 degrees C for 24, 48, and 72 h. The broth media were supplemented with 2% NaCl for some antimicrobial agents, and the agar dilution method was used with and without the addition of 4% NaCl. The CNS were identified to species by the method of Kloos and Schleifer. The results showed a lack of concordance between two hospitals with respect to oxacillin susceptibility testing by agar dilution with no NaCl supplement. The reasons are not clear but may be related to variations in media. The 4% NaCl supplement or extended incubation to 48 h eliminated this difference. The cefazolin and cefotaxime susceptibility results in the agar disk diffusion test were unreliable if accepted at face value. Cefamandole testing correlated well with the reference method regardless of the method used, and salt supplementation is not recommended. Most of the oxacillin-resistant CNS were resistant to the other beta-lactam drugs except cefamandole. Of 22 CNS resistant to cefamandole, 21 were S. haemolyticus.

Predictors of asymptomatic gonorrhea among patients seen by private practitioners

Nineteen physicians participating in a program for detecting and treating gonorrhea and other sexually transmitted diseases (STD) in high-risk groups filled out encounter forms for the initial visits by the first 3144 patients. This information was used to describe the program users and, by means of logistic regression analysis, to identify predictors of gonorrhea in asymptomatic patients. Overall, 17.3% of the users had culture-proved gonorrhea. Of the symptomatic patients 24.5% had gonorrhea. Of the asymptomatic patients 20.4% of those with a history of contact with a known or suspected case of STD had the disease, and 5.3% of those without a history of contact had the disease. The independent predictors of gonorrhea identified were, in order of importance, a history of contact with a case of STD and being aged less than 30 years. These predictors underline the importance of contact tracing, an underused but productive method of gonorrhea control that can be used effectively in private practice.

In vitro inhibition of growth of Neisseria gonorrhoeae by Neisseria meningitidis isolated from the pharynx of homosexual men

Despite the high prevalence of pharyngeal gonorrhea and of meningococcal carriage among homosexual men, Neisseria gonorrhoeae and Neisseria meningitidis are rarely co-isolated from the throat. Forty-seven meningococcal isolates from the pharynx of homosexual men were examined, by a lawn-spotting method, for their ability to inhibit N. gonorrhoeae in vitro. Eight (17%) of the meningococcal isolates were inhibitory when tested against gonococci from the same patient, while 31 (66%) were inhibitory when tested against N. gonorrhoeae strain 650 (T1). The colonial type T1 of a given strain was, in all cases tested, more sensitive to the inhibitory activities than the corresponding T4 type. Since the meningococci co-isolated from the throat with gonococci were at least as inhibitory in vitro as those isolated without gonococci, the natural resistance to gonococcal pharyngitis cannot be explained on the basis of the inhibitory activities produced by the meningococci in vitro. The inhibitory strains of N. meningitidis were identified in decreasing importance as: nonserogroupable, W135, C, B, 29E, and X. The addition of trypsin to the solid medium removed the inhibition produced by the meningococci, an observation suggesting the involvement of protein inhibitors.

[Use of cephalosporins as antibiotic prophylaxis in cesarean section]

Cefoxitin, a second-generation cephalosporin, was compared with cefazolin, a first-generation cephalosporin, and a placebo in a prospective, double-blind study of antibiotic prophylaxis in women undergoing nonelective cesarean section. In the groups that received cefazolin or the placebo there eas no statistically significant change in colonization of the cervix by aerobic bacteria by the fourth day after the operation, but there was a statistically significant increase in colonization by anaerobes. Cefoxitin had the opposite effect. Of the 14 postoperative infections in 11 patients, significantly more were in patients who had received the placebo; the numbers were too small to show a difference in effectiveness between the two antibiotics. Of the microorganisms implicated as the infectious agents, group B Streptococcus was the most frequent aerobe, and Peptostreptococcus and Bacteroides bivius were the most frequent anaerobes. Among the 15 patients for whom at least one perioperative specimen yielded positive culture results, a postoperative infection developed in 5 of the 6 who received the placebo, 2 of the 4 who received cefazolin and 1 of the 5 who received cefoxitin.