Real-time polymerase chain reaction detection of methicillin-resistant Staphylococcus aureus: impact on nosocomial transmission and costs.

OBJECTIVES: To assess the impact of real-time polymerase chain reaction (PCR) detection of methicillin-resistant Staphylococcus aureus (MRSA) on nosocomial transmission and costs. DESIGN: Monthly MRSA detection rates were measured from April 1, 2000, through December 31, 2005. Time series analysis was used to identify changes in MRSA detection rates, and decision analysis was used to compare the costs of detection by PCR and by culture.Setting. A 1,200-bed, tertiary care hospital in Canada. PATIENTS: Admitted patients at high risk for MRSA colonization. MRSA detection using culture-based screening was compared with a commercial PCR assay. RESULTS: The mean monthly incidence of nosocomial MRSA colonization or infection was 0.37 cases per 1,000 patient-days. The time-series model indicated an insignificant decrease of 0.14 cases per 1,000 patient-days per month (95% confidence interval, -0.18 to 0.46) after the introduction of PCR detection (P=.39). The mean interval from a reported positive result until contact precautions were initiated decreased from 3.8 to 1.6 days (P<.001). However, the cost of MRSA control increased from Can$605,034 to Can$771,609. Of 290 PCR-positive patients, 120 (41.4%) were placed under contact precautions unnecessarily because of low specificity of the PCR assay used in the study; these patients contributed 37% of the increased cost. The modeling study predicted that the cost per patient would be higher with detection by PCR (Can$96) than by culture (Can$67). CONCLUSION: Detection of MRSA by the PCR assay evaluated in this study was more costly than detection by culture for reducing MRSA transmission in our hospital. The cost benefit of screening by PCR varies according to incidences of MRSA colonization and infection, the predictive values of the assay used, and rates of compliance with infection control measures.

Impact and cost of infection control measures to reduce nosocomial transmission of extended-spectrum beta-lactamase-producing organisms in a non-outbreak setting.

We evaluated the impact of infection control interventions to reduce nosocomial extended-spectrum beta-lactamase (ESBL) transmission in a non-outbreak setting. This study was conducted at a tertiary 1200-bed hospital in Canada. The incidence of ESBLs was based on recovery of clinical isolates and assessed prospectively from 1999 to 2005. The incidence increased significantly from 0.28 to 0.67 per 1000 admissions during this period (P<0.001), reflecting an increase in the regional ESBL incidence from 1.32 to 9.28 per 100 000 population (P<0.001). Despite this increase, nosocomial ESBL rates increased only marginally, suggesting that infection control measures had an impact on nosocomial transmission. Infection control measures consisted of isolating all ESBL patients, as well as implementing the use of contact precautions for those with a high risk for transmission. The cost of these measures was CN$138 046.00 per year and CN$3191.83 per case admitted. A combination of control measures including active surveillance cultures, contact precautions for all colonized or infected patients and antimicrobial stewardship is required to significantly reduce the incidence of ESBLs.

Delays in the administration of antibiotics are associated with mortality from adult acute bacterial meningitis.

BACKGROUND: Bacterial meningitis continues to cause high mortality. Few studies address the possible association between this mortality and antibiotic administration delays. AIM: To determine whether delays in antibiotic administration are associated with mortality from bacterial meningitis, and to identify inappropriate diagnostic-treatment sequences leading to such delays. DESIGN: Retrospective case record study. METHODS: We reviewed 123 cases of adult acute bacterial meningitis in 119 patients aged >/=16 years admitted to hospital from January 1990 to March 2002, using multivariate regression analysis to assess the association between meningitis mortality and door-to-antibiotic time (the time elapsed between emergency room presentation and antibiotics administration). RESULTS: The case fatality rate was 13% (16/123). Adjusted odds ratios (OR) for mortality were: 8.4 (95%CI 1.7-40.9) for door-to-antibiotic time >6 h; 39.4 (95%CI 4.3-358.1) for afebrility at presentation; and 12.6 (95%CI 2.2-72.0) for severely impaired mental status at presentation. Factors associated with a door-to-antibiotic time of >6 h were: (i) failure to administer antibiotics prior to transfer from another institution (OR 21.8); (ii) the diagnostic-treatment sequence: head CT then lumbar puncture, then antibiotics (OR 5.6); and (iii) the absence of the classic meningitis triad (OR 4.9). DISCUSSION: There is an independent incremental association between delays in administrating antibiotics and mortality from adult acute bacterial meningitis. Inappropriate diagnostic-treatment sequences were significant predictors of such treatment delays.

Bacteremia due to persistent strains of coagulase-negative staphylococci in a neonatal intensive-care unit.

This retrospective case-control study was performed to determine risk factors for bacteremia due to persistent coagulase-negative staphylococci in our neonatal intensive-care unit. Enteral nutrition and the presence of a nasogastric tube were identified as possible risk factors for coagulase-negative staphylococcal bacteremia involving one of the persistent strains.

Epidemiology of methicillin-resistant Staphylococcus aureus in three Canadian tertiary-care centers.

OBJECTIVE: To describe the epidemiology and spread of methicillin-resistant Staphylococcus aureus (MRSA) in three tertiary-care centers in Ottawa, Ontario, Canada, where MRSA is encountered infrequently. DESIGN: Retrospective review over a 6-year period, from January 1, 1990, through December 31, 1995. SETTING: Three tertiary-care teaching hospitals in Ottawa. PARTICIPANTS: Patients and healthcare workers (HCWs) with MRSA isolated from any body site. METHODS: Patients and HCWs were identified retrospectively through hospital microbiology and infection control records. Patient charts were reviewed for clinical and epidemiological data, including age, gender, previous hospital admissions (where noted), and current and recent antibiotic use. MRSA isolates that were available were typed using pulsed-field gel electrophoresis (PFGE). Methicillin resistance was confirmed by standard methods and by polymerase chain reaction using mecA-specific primers. RESULTS: MRSA was identified in 53 patients and 2 HCWs. Three patients were excluded from further analysis because medical records were incomplete. Epidemiological data were collected on the remaining 52 individuals. Thirty-nine isolates from 31 patients and 2 HCWs were available for PFGE typing. Five epidemiologically linked nosocomial clusters involving 10 patients and 2 HCWs were identified and were confirmed by PFGE. MRSA isolates from a sixth cluster were not available for PFGE. In each cluster, nosocomial spread was minimized by standard infection control practices, including strict isolation of patients and screening of contacts. There was no evidence of secondary spread of MRSA involving the remaining 36 patients. Recent antibiotic use, surgery, admission to an intensive-care unit, and previous hospitalization were common among patients. There was no evidence of spread of MRSA among the three hospitals, and no endemic strains were apparent in any of these centers. CONCLUSIONS: MRSA remains an infrequent isolate in our centers, with no apparent interhospital spread. In institutions with little or no endemic MRSA, rigorous application of standard infection control practices is effective in limiting nosocomial transmission of this organism.

Three-year outbreak of pseudobacteremia with Burkholderia cepacia traced to a contaminated blood gas analyzer.

Between November 1990 and June 1993, Burkholderia cepacia was isolated from the blood cultures of 13 neonates born at the Ottawa General Hospital. Eight of the 13 neonates appeared symptomatic, and only 4 were treated with appropriate antimicrobial therapy, but all improved clinically. In August 1993, the blood gas analyzer in the neonatal intensive-care unit was found to be contaminated heavily with B cepacia. Eight available patient isolates were identical to the isolates recovered from the blood gas analyzer by ribotyping analysis. Infection control measures were implemented to prevent future contamination of the analyzer, and no further cases have been identified.

Polymicrobial tenosynovitis with Pasteurella multocida and other gram negative bacilli after a Siberian tiger bite.

Mammalian bites present a considerable clinical problem because they are often associated with bacterial infections. Pasteurella multocida is a microorganism that commonly infects both canine and small feline bites. Zoonotic infections developing after large feline bites have been recognised, although their reports are limited. We describe a 35 year old man who was bitten by a Siberian tiger and who developed infectious tenosynovitis secondary to P multocida, Bergeyella (Weeksella) zoohelcum, and Gram negative bacteria most like CDC group EF-4b and comamonas species. The latter three bacteria have not been isolated previously from large feline bite wounds.

Oxacillin susceptibility testing of Staphylococcus saprophyticus using disk diffusion, agar dilution, broth microdilution, and the Vitek GPS-105 card.

Eighty-three mecA negative isolates of S. saprophyticus had oxacillin zone diameters

Culture of dialysate in suspected CAPD associated peritonitis using the BacT/Alert system.

The BacT/Alert blood culture system was evaluated as a method of culturing dialysates by comparing inoculation of culture bottles directly (DBTA) or after centrifugation of 50 mL of dialysate (CBTA) with conventional culture. Of the 122 dialysates cultured, 84 were positive by one of the 3 methods. After eliminating contaminants, DBTA and CBTA detected 84% (59 of 70) and 93% (65 of 70) of the positive cultures, respectively, compared to 77% (54 of 70) for conventional culture. CBTA and DBTA detected 87% (82 of 94) and 73% (68 of 94) of the significant organisms isolated, respectively, compared to 61% (57 of 94) by conventional culture. However, 60% of the contaminants occurred with the CBTA method. When a dialysate was positive by all 3 methods, both BacT/ Alert methods detected growth earlier by a mean of almost 19 hours. The BacT/Alert system is a useful alternative method for culturing dialysates with the advantages of an earlier detection of positive cultures and minimal handling for the processing of negative cultures.

Direct detection of mecA, nuc and 16S rRNA genes in BacT/Alert blood culture bottles.

A benzyl alcohol-guanidine hydrochloride extraction method was used to remove sodium polyanetholesulfonate present in BacT/Alert blood culture bottles. Multiplex PCR using touchdown annealing was used to detect the mecA, nuc, and 16S rRNA genes in bottles growing staphylococci. This direct PCR assay demonstrated excellent sensitivity, specificity and improved accuracy compared to routine phenotypic methods for determination of methicillin resistance in coagulase negative staphylococci (CoNS). However, with this PCR assay, bottles that contained both methicillin-resistant CoNS and methicillin-susceptible Staphylococcus aureus would be misidentified as containing methicillin-resistant S. aureus.

Comparison of phenotypic methods to identify enterococci intrinsically resistant to vancomycin (VanC VRE).

Clinical laboratories must be able to differentiate between enterococci possessing acquired resistance to vancomycin (vanA and vanB genotypes) from those that are inherently resistant (vanC1 and vanC2/C3 genotypes). We compared several routine phenotypic tests to determine the species identity of clinical isolates of enterococci and a PCR assay for the van ligase genes was used to confirm identification of VanC VRE. The Vitek Gram Positive Identification card identified 53/60 (88%) Enterococcus faecalis and E. faecium isolates and 81/141 (57%) VanC VRE without additional testing. Another 32 of the VanC VRE required additional testing (e.g., motility and pigmentation) for correct identification. However, 7 of these 32 VanC VRE were nonmotile. The rapid ID 32 STREP strips identified 50/60 (83%) E. faecalis and E. faecium isolates and 102/141 (72%) VanC VRE. All E. faecalis and E. faecium isolates were nonmotile and did not acidify 1% methyl-alpha-D-glucopyranoside (MGP). Only 93/115 (81%) E. gallinarum and 21/26 (81%) E. casseliflavus/E. flavescens were motile but all 141 VanC VRE acidified MGP. MGP acidification can accurately differentiate VanC VRE from E. faecalis and E. faecium. Because some VanC VRE isolates are nonmotile, MGP acidification is preferred as a simple and less costly test for identification of these isolates.

Detection of methicillin resistance in coagulase-negative staphylococci initially reported as methicillin susceptible using automated methods.

Reliable detection of methicillin resistance in coagulase-negative staphylococci (CNS) is required for appropriate therapy of serious infections from these pathogens. To determine the most accurate method of measuring methicillin resistance in CNS initially reported as methicillin susceptible by automated methods, we compared mecA detection by polymerase chain reaction (PCR) with phenotypic methods. One hundred eighty-eight blood culture isolates of CNS that were initially reported as susceptible to methicillin using commercial methods (Vitek or MicroScan) were tested by agar dilution, disk diffusion, oxacillin salt agar screen plate, and a multiplex PCR assay using primer sets for mecA and 16S rRNA. Sixteen isolates (8.5%) previously reported as methicillin susceptible by automated methods contained the mecA gene. MICs of these isolates ranged from 0.5 microgram/mL to > or = 128 micrograms/mL. Ten of these isolates had MICs equal to or below the NCCLS breakpoint of 2 micrograms/mL. Six of the 10 isolates (4 with MICs of 0.5 microgram/mL and 2 with MICs of 2 micrograms/mL) did not grow on any of the oxacillin screen plates after 48 h of incubation at 30 degrees C or 35 degrees C. All six isolates were induced to grow in the presence of oxacillin at 128 micrograms/mL by serial passaging on plates containing increasing concentrations of antibiotic. Retesting with MicroScan and Vitek detected methicillin resistance in 7 and 10 isolates, respectively. Disk diffusion testing with incubation for 48 h proved to be the next best method after PCR for detection of methicillin resistance (15 of 16 isolates). Commercial automated methods and some methods recommended by National Committee for Clinical Laboratory Standards may not detect methicillin resistance in CNS that carry the mecA gene and have MICs just below breakpoint.

The presence of serum antibody to the chlamydial heat shock protein (CHSP60) as a diagnostic test for tubal factor infertility.

OBJECTIVE: To study the utility of testing for heat shock protein 60 (CHSP60) antibodies in the diagnosis of tubal factor infertility. DESIGN: Prospective case control. SETTING: Canadian university hospital infertility clinic. PATIENT(S): Women presenting for infertility investigation. INTERVENTION(S): Sera were collected from 77 patients. MAIN OUTCOME MEASURE(S): The relationship between tubal factor infertility and the presence of antibodies to Chlamydia trachomatis and CHSP60 was assessed. RESULT(S): There were no significant differences between antibodies to C. trachomatis in women with tubal factor infertility (63%) and other causes of infertility (46%). However, more women with tubal factor infertility (44%) had anti-CHSP60 antibodies compared with other causes of infertility (8%). Antibody testing for C. trachomatis has only a 63% sensitivity and a 54% specificity for detecting tubal factor infertility. In contrast, the CHSP60 antibody test has a 44% sensitivity and a 92% specificity for detecting tubal factor infertility. There is a good positive likelihood ratio of 5.5 for CHSP60 antibody testing detecting the presence of tubal factor infertility. Combining CHSP60 antibody with antibody testing for C. trachomatis has an excellent positive likelihood ratio of 10 for the detection of C. trachomatis-associated tubal factor infertility. CONCLUSION(S): CHSP60 antibody testing is a more accurate test than antibody testing for C. trachomatis for predicting chlamydia-associated tubal factor infertility. These tests, when used in combination at initial infertility evaluation, would provide a rapid noninterventive means of diagnosing tubal factor infertility.

Does serologic evidence of remote Chlamydia trachomatis infection and its heat shock protein (CHSP 60) affect in vitro fertilization-embryo transfer outcome?

OBJECTIVE: To examine IVF-ET outcome in patients with and without serologic evidence of Chlamydia trachomatis infection and chlamydia heat shock protein 60 (CHSP 60) antibodies. DESIGN: Retrospective case control. SETTING: University-affiliated IVF-ET program. MAIN OUTCOME MEASURES: A total of 195 IVF-ET patients with tubal factor infertility underwent oocyte pick-up, 166 of these women had ET resulting in a total of 37 pregnancies. Serum antibody testing for evidence of remote C. trachomatis and CHSP 60, as well as pregnancy outcome, were determined for all patients. RESULTS: There were no differences in pregnancy rates or outcomes between C. trachomatis seropositive versus seronegative groups: 27/118 (23%) C. trachomatis seropositive versus 10/77 (13%) C. trachomatis seronegative patients achieved pregnancy per oocyte pick-up. Pregnancy rates per ET were 27/105 (26%) in C. trachomatis seropositive versus 10/61 (16%) C. trachomatis seronegative patients. In the C. trachomatis positive subgroup, significantly higher pregnancy rates were found in the CHSP 60 antibody positive patients: 24/67 (36%) CHSP 60 positive versus 3/51 (6.0%) CHSP 60 negative patients were pregnant after oocyte pick-up (OR = 8.9, 95% CI = 2.3 to 27.5). Pregnancy rates per ET were 24/57 (42%) in CHSP 60 positive versus 3/48 (7%) CHSP 60 negative patients (OR = 10.9, 95% CI = 2.8 to 33.6). There were no significant differences in any group when examining the following pregnancy outcomes: spontaneous abortion, ectopic pregnancy, preterm and multiple pregnancy rates. CONCLUSIONS: [1] There are no differences in pregnancy rates or outcomes in patients with and without serologic evidence of previous C. trachomatis infections. [2] In women seropositive for C. trachomatis, significantly higher pregnancy rates are found in women who are CHSP 60 antibody positive versus negative. [3] Pregnancy outcomes do not appear to be different between these groups.

Staphylococcus epidermidis septic arthritis post arthroscopy.

A 61 year-old man developed painful swelling of his right knee shortly after arthroscopy of the joint. Synovial fluid analysis revealed a polymorphonuclear leukocytosis of 51,600 X 10(6) cells/litre and culture grew Staphylococcus epidermidis. He responded favorably to 4 weeks of intravenous therapy with cloxacillin. S. epidermidis, an important cause of prosthetic joint infection, must be considered a potential pathogen in other joint infections.

Noninvasive screening for genital chlamydial infections in asymptomatic men: Strategies and costs using a urine PCR assay.

OBJECTIVE: To evaluate cost saving strategies to screen for genital chlamydial infection in men using polymerase chain reaction (PCR) technology. METHODS: Men with no urethral symptoms presenting to a sexually transmitted disease (STD) clinic were recruited. Study participants underwent a questionnaire interview. Urethral swabs were taken to perform a smear for polymorphonuclear leucocytes (PMN) and for the detection of Chlamydia trachomatis by culture and PCR. First-catch urine was collected for a leukocyte esterase test (LET) and PCR. RESULTS: C trachomatis infection was detected in 36 of 463 (7.8%) men. LET and PMN were positive in 10 (28%) and 12 (33%) infected men, respectively. Risk factors for chlamydial infection were younger than age 25 years, LET-positive, PMN-positive and STD contact (P<0.001). The direct cost of genital chlamydial infection in men in Canada has been previously estimated at $381/case. Based on a sensitivity of 90% for urine PCR, the estimated direct cost of testing all participants to detect 32 cases was $453/case. Using risk factors recommended in the Canadian STD Guidelines (age younger than 25 years, new partner, STD contact or unprotected sex), the same number of cases would have been detected by testing only 384 men at $376/case. Using age younger than 25 years or STD contact as the screening criterion, 78% of those infected would have been detected at $259/case, and no new cases would have been detected by adding LET-positive or PMN-positive as risk factors. CONCLUSION: Targeted screening for chlamydial infection using urine PCR assay and risk factors recommended in the Canadian guidelines could substantially reduce the cost of screening at a STD clinic setting. LET and PMN smear did not appear to be useful indicators of chlamydial infection in this population.

Group A streptococcal endometritis: Report of an outbreak and review of the literature.

Two cases of group A streptococcus (gas) postpartum endometritis were diagnosed within 24 h following uncomplicated vaginal delivery. Investigation by the infection control service identified all 10 obstetric personnel who performed any invasive procedure on both cases. These personnel were questioned about a recent history of sore throat, skin lesions, vaginal or rectal symptoms. Throat and rectal cultures were obtained for gas from all 10 personnel. A carrier was identified among the personnel screened. This nurse was removed from direct patient care and treated with a two-week course of oral clindamycin and rifampin with documentation of carrier eradication of gas at the end of therapy, 30 days, 60 days and six months post-treatment. All three isolated strains were identical by restriction endonuclease analysis and by M and T typing. Rapid implementation of infection control measures were successful in arresting this outbreak, with no further cases of gas occurring in the subsequent year.

Chlamydia infection in street youth: Need for more aggressive screening programs.

OBJECTIVES: To determine, first, the sexual practices among street youth in the Ottawa-Carleton, Ontario region; second, the percentage of street youth who report previous sexually transmitted disease (STD) screening; and third, the rate of previous infection with Chlamydia trachomatis in this population. METHODS: This prospective street youth pilot study was cross-sectional in design. Street youth aged 15 to 20 years were recruited through a drop-in centre or shelter in Ottawa, Ontario between August and October 1993. Information on demographics, substance use, current sexual practices and STD screening and infection history were obtained through a structured face to face interview and a 75-item questionnaire. Past C trachomatis infection was determined by microimmunofluorescence assay with purified antigens of C trachomatis (serovars A to K), Chlamydia psittaci (avian strain 6BC) and Chlamydia pneumoniae (TW-183 strain). RESULTS: Ninety-eight per cent of the youth approached participated. Of the 100 street youth (61 males, mean age 17.8 years; 39 females, mean age 17.1 years), 94% were sexually active, with 21% of males and 26% of females having had four or more different sexual partners in the previous year. Only 27% of males and 8% of females reported consistent condom use with all partners all of the time. Thirty per cent of males and 50% of females reported previous STD testing. Of the 100 street youth, 22 (16 males and six females) had had previous C trachomatis infection by serotesting, but only three of 16 (19%) of these males and three of six (50%) of these females reported previous STD testing. None of the 22 recalled previous diagnosis or treatment for any STD. CONCLUSIONS: These street youth reported a high prevalence of risky sexual behaviour, and this supports the national STD guidelines for targeted screening in this population. The current screening guidelines for C trachomatis in this population do not reach the majority of street youth.

Urine testing for Chlamydia trachomatis and hassle-free follow-up is acceptable to street youth.

OBJECTIVE: To evaluate whether street youth would use a sexually transmitted disease (STD) screening program involving non-nominal, noninvasive testing of urine for Chlamydia trachomatis with hassle-free follow-up and partner self-notification. DESIGN: Cross-sectional pilot study in six centres frequented by street youth 13 to 25 years of age in the Regional Municipality of Ottawa-Carleton. INTERVENTIONS: A structured, non-nominal face-to-face interview using an 88-item questionnaire was administered by a trained research assistant. Immediate feedback was provided to participants about specific individual risk reduction strategies for high risk life styles. Each street youth provided a urine sample that was tested non-nominally for C trachomatis by polymerase chain reaction (PCR). A single dose of azithromycin therapy was provided to participants who tested positive, each of whom was requested to encourage recent sexual partners to come forward for testing and treatment. RESULTS: One hundred and sixty-three street youth were recruited (98 males and 65 females [male to female ratio 1.5:1]) over the four months of the study. The mean ages of participants were males 18.3+/-2.50 years and females 16.7+/-2.02 years. Ninety-two per cent (146) of all participants were sexually active and 99% of the sexually active youth (145 of 146) submitted urine samples. Urine samples were positive in 12 (8.2%) participants (seven males, five females), all of whom were asymptomatic. All those who tested positive were recruited from a single site (site specific rate 13.6%). Overall, only 25% of those tested returned spontaneously for test results; however, nine of 12 participants with positive results were treated due to investigator vigilance in locating the youth. Street youth partner self-notification resulted in five additional street youth requesting testing and treatment. CONCLUSIONS: Street youth participated in a STD testing program when a street friendly program and noninvasive methods were used. Although more expensive, urine PCR testing increased program acceptance by street youth compared with previous local results. Detection of C trachomatis was high in this hard-to-reach population. There is a need to address further the problem of poor return rates for results and treatment, as well as low rates of partner notification.

Relationship between antenatal group B streptococcal vaginal colonization and premature labour.

OBJECTIVE: To determine whether a population of pregnant women with group B streptococcal (GBS) vaginal colonization had an increased risk of specific epidemiological and intrapartum risk factors for early onset GBS disease. SETTING: Tertiary university centre in Ottawa, Ontario. DESIGN: Hospital-based retrospective cohort study. METHODS: Pregnant women who gave birth during a four-month period in 1994 were included in the study. Potential GBS risk factors were obtained from a review of medical records. The prevalence of each risk factor in colonized and noncolonized women was examined using chi(2) or Fisher's exact test. Multiple logistic regression was performed. RESULTS: A total of 986 women, including 94 (9.5%) women colonized with GBS, were studied. The proportion of women younger than 20 years of age in the colonized group was 2.1% (two of 94) versus 4.6% (41 of 891) in the noncolonized group (P=0.28). Similar rates of multiple births were observed among the colonized and noncolonized groups (2.1% [two of 94] versus 2.5% [22 of 891], respectively) (P=0.94). Likewise, there were no significant differences in either group in the prevalence of a previous pregnancy affected by GBS or diabetes mellitus (P=0.82 and P=0.79, respectively). Multivariable analyses indicated that women who were colonized with GBS were more than twice as likely to deliver prematurely (below 37 weeks' gestational age) (odds ratio [OR] 2.43, 95% CI 1.39 to 4.23). Similarly, colonized women were more likely to be febrile during labour (at least 38 degrees C) (OR 5.05, 95% CI 1.70 to 15.02). CONCLUSION: GBS vaginal colonization was associated with premature labour and intrapartum pyrexia in the population studied. According to Canadian and American guidelines, women with GBS vaginal colonization qualify for intrapartum chemoprophylaxis. The study results suggest that the identification of women at risk of premature labour may be one advantage of early prenatal screening for GBS.