Trends in the use of laboratory tests for the diagnosis of Clostridium difficile infection and association with incidence rates in Quebec, Canada, 2010-2014.

BACKGROUND: Several Clostridium difficile infection (CDI) surveillance programs do not specify laboratory strategies to use. We investigated the evolution in testing strategies used across Quebec, Canada, and its association with incidence rates. METHODS: Cross-sectional study of 95 hospitals by surveys conducted in 2010 and in 2013-2014. The association between testing strategies and institutional CDI incidence rates was analyzed via multivariate Poisson regressions. RESULTS: The most common assays in 2014 were toxin A/B enzyme immunoassays (EIAs) (61 institutions, 64%), glutamate dehydrogenase (GDH) EIAs (51 institutions, 53.7%), and nucleic acid amplification tests (NAATs) (34 institutions, 35.8%). The most frequent algorithm was a single-step NAAT (20 institutions, 21%). Between 2010 and 2014, 35 institutions (37%) modified their algorithm. Institutions detecting toxigenic C difficile instead of C difficile toxin increased from 14 to 37 (P < .001). Institutions detecting toxigenic C difficile had higher CDI rates (7.9 vs 6.6 per 10,000 patient days; P = .01). Institutions using single-step NAATs, GDH plus toxigenic cultures, and GDH plus cytotoxicity assays had higher CDI rates than those using an EIA-based algorithm (P < .05). CONCLUSIONS: Laboratory detection of CDI has changed since 2010. There is an association between diagnostic algorithms and CDI incidence. Mitigation strategies are warranted.

Optical nonlinearity for few-photon pulses on a quantum dot-pillar cavity device.

Giant optical nonlinearity is observed under both continuous wave and pulsed excitation in a deterministically coupled quantum dot-micropillar system, in a pronounced strong-coupling regime. Using absolute reflectivity measurements we determine the critical intracavity photon number as well as the input and output coupling efficiencies of the device. Thanks to a near-unity input-coupling efficiency, we demonstrate a record nonlinearity threshold of only 8 incident photons per pulse. The output-coupling efficiency is found to strongly influence this nonlinearity threshold. We show how the fundamental limit of single-photon nonlinearity can be attained in realistic devices, which would provide an effective interaction between two coincident single-photons.

Agreement analysis of LENSTAR with other techniques of biometry.

PURPOSE: To assess the agreement of the optical low-coherence reflectometry (OLCR) device LENSTAR LS900 with partial coherence interferometry (PCI) device IOLMaster and applanation and immersion ultrasound biometry. METHODS: We conducted the study at the Ophthalmology Clinic, University of Malaya Medical Center, Malaysia. Phakic eyes of 76 consecutive cataract patients were measured using four different methods: IOLMaster, LENSTAR and A-scan applanation and immersion ultrasound biometry. We assessed the method agreement in the LENSTAR-IOLMaster, LENSTAR-applanation, and LENSTAR-immersion comparisons for axial length (AL) and intraocular lens (IOL) power using Bland-Altman plots. For average K, we compared LENSTAR with IOLMaster and the TOPCON KR-8100 autorefractor-keratometer. SRK/T formula was used to compute IOL power, with emmetropia as the target refractive outcome. RESULTS: For all the variables studied, LENSTAR agreement with IOLMaster is strongest, followed by those with immersion and applanation. For the LENSTAR-IOLMaster comparison, the estimated proportion of differences falling within 0.33 mm from zero AL and within 1D from zero IOL power is 100%. The estimated proportion of differences falling within 0.5 D from zero average K is almost 100% in the LENSTAR-IOLMaster comparison but 88% in the LENSTAR-TOPCON comparison. The proportion of differences falling within 0.10 mm (AL) and within 1D (IOL power) in the LENSTAR-IOLMaster comparison has practically significant discrepancy with that of LENSTAR-applanation and LENSTAR-immersion comparisons. CONCLUSIONS: In phakic eyes of cataract patients, measurements of AL, average K, and IOL power calculated using the SRK/T formula from LENSTAR are biometrically equivalent to those from IOLMaster, but not with those from applanation and immersion ultrasound biometry.

Identification of multidrug- and carbapenem-resistant Acinetobacter baumannii in Canada: results from CANWARD 2007.

OBJECTIVES: Multidrug-resistant (MDR) Acinetobacter baumannii is a growing concern in many countries. This report describes patient demographics, antimicrobial susceptibilities and molecular characteristics of A. baumannii cases identified through the Canadian Ward Surveillance Study (CANWARD). In addition, clinical cases involving MDR carbapenem-resistant A. baumannii are also detailed in this report. METHODS: From January to December 2007, 12 hospital centres across Canada submitted pathogens from clinics, emergency rooms, intensive care units and medical/surgical wards as part of the CANWARD study. MICs were determined using microbroth dilution (CLSI). PCR and sequence analysis identified OXA genes among carbapenem-resistant isolates. PFGE was used to determine genetic relatedness and compare representatives of the Midlands 2 strain, OXA-23 clone 1 or 2, T strains and isolates collected from military sources. RESULTS: This study identified A. baumannii in 0.33% (n = 26) of infections. The majority of isolates remained susceptible to the antimicrobials tested, however, 7.7% (n = 2) displayed an MDR phenotype, including resistance to carbapenems. In one isolate bla(OXA-58) was found to be the likely cause of carbapenem resistance while the other isolate had an insertion sequence element upstream of its intrinsic bla(OXA-51). The clinical data of these two isolates suggest that one is travel-related while the source of the other remains unknown. CONCLUSIONS: A. baumannii infections from Canadian hospitals were relatively low. Carbapenem-resistant MDR A. baumannii were also rare and unrelated to previously observed isolates from military sources. Continued surveillance in Canada is suggested in order to determine if such organisms will become a problem.

The use of preserved bovine pericardium for emergency temporizing graft in corneal perforation.

Corneal perforation is an ocular emergency that requires early intervention to avoid permanent visual loss from endophthalmitis or irreversible structural changes. Although tectonic keratoplasty is the best choice for patching a large perforation, a donor cornea is not always immediately available. Consequently, an alternative material is required while awaiting a donor cornea. We report the use of preserved bovine pericardium as a temporizing graft to maintain the ocular integrity in two patients with corneal perforation.

Pursuing scale and quality in STI interventions with sex workers: initial results from Avahan India AIDS Initiative.

BACKGROUND: Migration, population mobility, and sex work continue to drive sexually transmitted epidemics in India. Yet interventions targeting high incidence networks are rarely implemented at sufficient scale to have impact. India AIDS Initiative (Avahan), funded by the Bill and Melinda Gates Foundation, is scaling up interventions with sex workers (SWs) and other high risk populations in India's six highest HIV prevalence states. METHODS: Avahan resources are channelled through state level partners (SLPs) to local level non-governmental organisations (NGOs) who organise outreach, community mobilisation, and dedicated clinics for SWs. These clinics provide services for sexually transmitted infections (STIs) including Condom Promotion, syndromic case management, regular check-ups, and treatment of asymptomatic infections. SWs take an active role in service delivery. STI capacity building support functions on three levels. A central capacity building team developed guidelines and standards, trains state level STI coordinators, monitors outcomes, and conducts operations research. Standards are documented in an Avahan-wide manual. State level STI coordinators train NGO clinic staff and conduct supervision of clinics based on these standards and related quality monitoring tools. Clinic and outreach staff report on indicators that guide additional capacity building inputs. RESULTS: In 2 years, clinics with community outreach for SWs have been established in 274 settings covering 77 districts. Mapping and size estimation have identified 187,000 SWs. In a subset of four large states covered by six SLPs (183,000 estimated SWs, 65 districts), 128,326 (70%) of the SWs have been contacted through peer outreach and 74,265 (41%) have attended the clinic at least once. A total of 127,630 clinic visits have been reported, an increasing proportion for recommended routine check ups. Supervision and monitoring facilitate standardisation of services across sites. CONCLUSION: Targeted HIV/STI interventions can be brought to scale and standardised given adequate capacity building support. Intervention coverage, service utilisation, and quality are key parameters that should be monitored and progressively improved with active involvement of SWs themselves.

Managing HIV-infected patients on antiretroviral therapy in Rio de Janeiro, Brazil: do providers follow national guidelines?

The objective of the paper was to compare provider practices in prescribing antiretroviral (ARV) drug regimens and use of laboratory monitoring at three health care facilities and to determine whether Brazilian national guidelines are being followed. A retrospective, cross-sectional survey was employed. We selected a sequential sample of patients on ARV therapy who registered at three health care facilities in Rio de Janeiro, Brazil, during 2001. We abstracted 2001 patient visit data from medical records using standardized data forms. Provider practice was compared to the 2000 Brazil national guidelines for ARV use. Providers who prescribed recommended or acceptable regimens were considered as having conformed to guidelines. Only 2% of patient records (N=984) reported use of inappropriate regimens as defined by the Brazil 2000 national ARV guidelines. Forty-nine per cent of patients at the Evandro Chagas hospital, 17% of those at Hospital Geral, and 57% of those at Centro da Saude were prescribed recommended therapies. Twenty per cent of patients seen at the public district hospital received dual ARV therapy, an acceptable regimen at the time. Although the national guidelines do not provide recommendations on laboratory monitoring, during the 1 year study period a majority of patients had at least one CD4+ cell count (92%) or viral load measurement (86%). Providers' practices in prescribing ARV regimens at these Rio de Janeiro facilities conform to national guidelines. Physicians would benefit from Brazilian ARV guidelines which incorporate the international consensus on the frequency of laboratory monitoring appropriate for patients in resource-constrained settings.

Multilaboratory comparison of proficiencies in susceptibility testing of Helicobacter pylori and correlation between agar dilution and E test methods.

Susceptibility testing was performed at seven Canadian microbiology laboratories and the Helicobacter Reference Laboratory, Halifax, Nova Scotia, Canada, to assess susceptibility testing proficiency and the reproducibility of the results for clarithromycin and metronidazole and to compare the Epsilometer test (E test) method to the agar dilution reference method. Control strain Helicobacter pylori ATCC 43504 (American Type Culture Collection) and 13 clinical isolates (plus duplicates of four of these strains including ATCC 43504) were tested blindly. The National Committee for Clinical Laboratory Standards (NCCLS) guidelines for agar dilution testing were followed, and the same suspension of organisms was used for agar dilution and E test. Antimicrobials and E test strips were provided to the investigators. Methods were provided on a website (www.Helicobactercanada.org). Each center reported MICs within the stated range for strain ATCC 43504. Compared to the average MICs, interlaboratory agreements within 2 log(2) dilutions were 90% (range, 69 to 100%) for clarithromycin by agar dilution, with seven very major errors [VMEs], and 85% (range, 65 to 100%) by E test, with three VMEs. Interlaboratory agreements within 2 log(2) dilutions were 83% (range, 50 to 100%) for metronidazole by agar dilution, with six VMEs and eight major errors (MEs), and 75% (range, 50 to 94%) by E test, with four VMEs and four MEs. At lower and higher concentrations of antibiotic, E test MICs were slightly different from agar dilution MICs, but these differences did not result in errors. When a standardized protocol based on NCCLS guidelines was used, most participants in this study correctly identified clarithromycin- and metronidazole-susceptible and -resistant strains of H. pylori 93% of the time by either the agar dilution or E test method, and the numbers of errors were relatively equivalent by both methods.

Factores asociados a niveles de parathormona intacta (PTHi): en 136 pacientes en hemodiálisis crónica / Associated factors of levels intact parathormone (PTHi): at 136 patients of chronic hemodialysis

El hiperparatiroidismo secundario (HPT2) es una complicación de alta prevalencia en pacientes en hemodiálisis crónica (HD) (1,2,3). El objetivo de este estudio fue conocer la correlación existente entre factores demográficos, nutricionales y bioquímicos, con la severidad del HPT2 medido a través de los niveles plasmáticos de parathormona intacta (PTHi). La población estudiada fue de 136 pacientes en HD trisemanal (84 hombres, 52 mujeres y 28 diabéticos en el grupo total). Edad promedio de 53,9 años (DS 19,6), PTHi promedio de 326 pg/dl (DS 591). Se calculó los promedios diarios de ingesta calórica, proteica y de fosfatos a partir de recordatorio de ingesta en 24 hrs. La ingesta calórica fue de 1.735 kcal, la proteica de 55,9 g y la de fosfatos de 875 mg en 24 horas respectivamente.Los pacientes diabéticos presentaron niveles menores de PTHi (179 pg/dl), con relación a los no diabéticos cuyos valores de PTHi (456,7 pg/dl) fueron significativamente mayores.Se encontró una correlación directa entre la ingesta de fosfatos con la ingesta calórica y la proteica. Los niveles de PTHi se correlacionaron directamente con el tiempo de permanencia en HD medido en meses (mHD) y tuvieron correlación inversa con la edad, ingesta calórica, ingesta de fosfatos y fosfatemia

Lower respiratory tract infections in Inuit infants on Baffin Island.

BACKGROUND: It has long been suspected that Canadian Inuit children suffer from frequent severe lower respiratory tract infections (LRTIs), but the causes and risk factors have not been documented. This study assessed the infectious causes and other epidemiologic factors that may contribute to the severity of LRTI in young Inuit children on Baffin Island. METHODS: A prospective case study was carried out at the Baffin Regional Hospital in Iqaluit, Nunavut, of infants less than 6 months of age, who were admitted to hospital between October 1997 and June 1998 with a diagnosis of LRTI. Immunofluorescent antibody testing was used to identify respiratory viruses, and enzyme immunoassay (EIA) and polymerase chain reaction (PCR) were used to test for Chlamydia trachomatis. Demographic and risk factor data were obtained through a questionnaire. RESULTS: The annualized incidence rate of admission to hospital for bronchiolitis at Baffin Regional Hospital was 484 per 1000 infants who were less than 6 months of age; 12% of the infants were intubated. Probable pathogens were identified for 18 of the 27 cases considered in our study. A single agent was identified for 14 infants: 8 had respiratory syncytial virus, 2 adenovirus, 1 rhinovirus, 1 influenza A, 1 parainfluenza 3 and 1 had cytomegalovirus. For 4 infants, 2 infectious agents were identified: these were enterovirus and Bordetella pertussis, adenovirus and enterovirus, cytomegalovirus and respiratory syncytial virus, and respiratory syncytial virus and adenovirus. C. trachomatis was not identified by either EIA or PCR. All infants were exposed to maternal smoking in utero, second-hand smoke at home and generally lived in crowded conditions. INTERPRETATION: Inuit infants in the Baffin Region suffer from an extremely high rate of hospital admissions for LRTI. The high frequency and severity of these infections calls for serious public health attention.

Surveillance of invasive Streptococcus pneumoniae infection in the province of Quebec, Canada, from 1996 to 1998: serotype distribution, Antimicrobial susceptibility, and clinical characteristics.

In the province of Quebec, Canada, from 1996 to 1998, 3,650 invasive Streptococcus pneumoniae infections were reported. A total of 1,354 isolates were serotyped and tested for antimicrobial susceptibility. The distribution of serotypes remained stable over the 3 years, with serotypes 14, 6B, 4, 9V, 23F, and 19F accounting for 61% of the isolates. Overall, 90% of isolates were included in the current 23-valent vaccine and 67% were included in the 7-valent conjugate vaccine. We were able to determine that resistance to penicillin and to other antibiotics is increasing.

Antiretroviral therapy and declining AIDS mortality in New York City.

The objective was to evaluate the association between antiretroviral therapy and AIDS mortality in New York City (NYC). Design was a population-based case-control study. We randomly selected 150 case patients and 150 control patients whose AIDS diagnosis was made during 1994 to 1996 (male:female, 2:1) from among 19,238 persons reported to the NYC Health Department HIV/AIDS Reporting System (HARS). Case patients had died of AIDS-related causes in 1996. Control patients, category matched with case patients on gender, were not known to have died by the end of 1996. Analysis was performed on 279 patients (142 cases and 137 controls). Cases and controls were similar in age, gender, race, HIV transmission category, and health insurance coverage. The median baseline CD4 count was 30 cells/microL for those who died and 103 cells/microL for survivors (p < 0.001). The prescription of HAART (antiretroviral combination that includes at least one protease inhibitor) in 1996 was strongly associated with survival in univariate analysis (OR = 5.1, 95%CI = 2.5-10.2). This association remained in a logistic regression analysis after adjusting for sex, age, race, health insurance status, HIV transmission categories, year of AIDS diagnosis, baseline CD4 count, and other antiretroviral therapy (AOR = 8.6, 95%CI = 3.5-20.7). Prescription of combination therapy other than HAART in 1996 and baseline CD4 count were also associated with survival, but less strongly so. The survival benefit of HAART extends beyond the confines of a few highly selected patients into the "real world," reducing AIDS deaths at the population level. This population-based study supports the likelihood that the introduction of HAART in 1996 played a primary role in the decline in NYC AIDS mortality.

Genetic variability determinants of Helicobacter pylori: influence of clinical background and geographic origin of isolates.

Helicobacter pylori has an unusual pattern of genetic variation, which complicates research on this organism. To gain a better understanding of the forces behind this phenomenon, the extent to which recombination and single point mutations affect genetic variability in H. pylori was quantified and the influence of both geographical distance and clinical background were assessed. Site-directed restriction-endonuclease digestion of 2 gene fragments was performed on 168 isolates from Montreal and Berlin. Allelic diversity was found to be much higher for H. pylori than for other bacterial species. This finding is consistent with those of previous studies on H. pylori that were conducted using other techniques. However, nucleotide diversity was within the range reported for other bacterial species. Phylogenetic analysis found no grouping of strains with clinical background or geographical origin. Recombination at a rate that resulted in linkage equilibrium within genes can explain these observations.

Is Helicobacter pylori eradication associated with gastroesophageal reflux disease?

OBJECTIVES: A recent report has suggested an association between Helicobacter pylori eradication and the development of gastroesophageal reflux disease (GERD). We therefore assessed the incidence of GERD among comparable patients having undergone successful versus failed H. pylori eradication in a controlled trial. We also compared the H. pylori strains in the subjects that developed GERD to those that did not. METHODS: Patients with a history of proven duodenal ulcer and H. pylori infection were randomised into a H. pylori eradication study. Patients subsequently underwent gastroscopy with gastric biopsies every 3 months for 1 yr. At each visit, the presence of GERD symptoms and endoscopic esophagitis were noted, and the incidence of these variables among patients in whom H. pylori eradication was successful was compared to those in whom it was not. In a subgroup, the presence of the cagA, cagE, and vacA genotypes and of cagA antibodies were determined. RESULTS: Of 98 patients randomized into this study, 11 dropped out before determination of H. pylori eradication, leaving 87 patients with analyzable results. H. pylori eradication was successful in 63 (72%). By the end of the follow-up period, patients with GERD symptoms or endoscopic esophagitis were more prevalent in the successful than in the failed eradication group (37% [95% CI: 25-50%] vs 13% [95% CI: 3-32%], p = 0.04, 95% CI for the difference: 6-42%), as were patients with GERD symptoms alone (29% [95% CI: 18-41%] vs 8% [95% CI: 1-27%], p = 0.04, 95% CI for the difference: 4-36%) or esophagitis alone (21% [95% CI: 12-33%] vs 4% [95% CI: 0-21%], p = 0.10, 95% CI for the difference: 4-29%, respectively). Multivariate analysis revealed no significant association between the incidence of symptoms or esophagitis and age, gender, Quetelet index, caffeine or alcohol intake, smoking, weight change, or the presence of a hiatus hernia. There were also no differences in the prevalence of H. pylori genotypes from patients who developed GERD as compared to those who did not. CONCLUSIONS: In this patient population, the incidence of new GERD-type symptoms or endoscopic esophagitis was greater in patients in whom successful eradication was achieved. This difference does not appear to be attributable to weight gain, habits, or specific H. pylori strains.

Association of Helicobacter pylori genotype with gastroesophageal reflux disease and other upper gastrointestinal diseases.

OBJECTIVE: Helicobacter pylori (H. pylori) is a recognized pathogen, but it may also have a protective effect for gastroesophageal reflux disease (GERD). We compared the prevalence of potential virulence factors (cagA, cagE, vacA genotypes) in GERD to other upper gastrointestinal diseases and controls. METHODS: A total of 405 patients underwent gastroscopy with H. pylori isolation and serum testing. Patient diagnostic subgroups were prospectively defined. Genotypes were determined by amplification using polymerase chain reaction. CagA antibodies were determined by western blot, enzyme-linked immunosorbent, and flow microsphere immunofluorescent assays. RESULTS: Patients were grouped as follows: nonulcer dyspepsia (26%), GERD (20%), gastric ulcer (17%), duodenal ulcer (12%), gastric cancer (6%), or controls (19%). The cagA gene was present in 94-97% of subjects in all categories, but the cagA antibody was less prevalent in nonulcer dyspepsia (69%, 95% CI: 48-86%, p = 0.02) and GERD (69%, CI: 39-91%, p < 0.05) than in those with gastroduodenal pathology including gastric ulcer, duodenal ulcer, and gastric cancer (92%, CI: 81-98%). The cagE gene and vacA S1 genotype were more frequent in patients with gastroduodenal pathology (p < 0.01). GERD was associated with a significantly lower rate of vacA S1 genotype than controls (29% (CI: 10-56%) versus 80% (CI: 59-93%), p < 0.01). The vacA S1 genotype was associated with the presence of cagA antibodies. CONCLUSIONS: The cagE and vacA S1 genotypes are more prevalent in patients with peptic ulcer or gastric cancer, suggesting a potential function in virulence for these genes. However, the vacA S1 genotype was also more prevalent in controls than GERD, suggesting a potential protective effect against GERD.

Predictors of failure of Helicobacter pylori eradication and predictors of ulcer recurrence: a randomized controlled trial.

OBJECTIVE: In light of evidence that Helicobacter pylori treatment fails 5% to 20% of the time, the objective of this study was to determine predictors of unsuccessful H. pylori eradication and of duodenal ulcer recurrence. DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Gastroenterology services of 2 general hospitals in Montreal, Que. PATIENTS: All patients (aged 16 to 90) with an endoscopically proven duodenal ulcer within the previous year and H. pylori infection detected on antral biopsy were asked to participate; 85 were included. INTERVENTIONS: Patients were randomized in double-blind fashion to 1 of 2 eradication therapies, consisting of metronidazole, bismuth subcitrate and either amoxicillin or placebo. Endoscopy was performed at follow-up every 3 months for 12 months. OUTCOME MEASURES: Demographic data, characteristics of patients and disease, previous history and family history of ulcer disease, compliance at day 10 and day 28 of therapy; in vitro metronidazole resistance of H. pylori; eradication of H. pylori (determined by endoscopic biopsy 3 months after therapy); and ulcer recurrence within 12 months after therapy. RESULTS: Metronidazole resistance (odds ratio [OR] 0.11, 95% confidence interval [CI] 0.017 to 0.69) was the only independent predictor of eradication. Compliance (as defined in the study), density of organisms on culture, as well as several other factors examined, were not significant predictors. Treatment group, although a significant factor on univariate analysis, was not an independent predictor on multivariate analysis, as there were relatively good eradication rates (82% and 97% among compliant patients) in both groups. With regard to ulcer recurrence, 3 independent predictors were identified: failed H. pylori eradication (OR 86.5, 95% CI 4.2 to 1769), unemployment (OR 13.2, 95% CI 1.8 to 95) and a family history of ulcer disease (OR 12.2, 95% CI 1.2 to 128). CONCLUSIONS: The best predictor of ulcer recurrence is failure of H. pylori eradication, which, in turn, depends on metronidazole resistance. Hence, treatments containing metronidazole should be avoided in populations with high rates of metronidazole resistance. A family history of ulcer disease and unemployment were also predictors of ulcer recurrence, which suggests a potential role for treatment of contacts.

Aortitis due to Salmonella: report of 10 cases and comprehensive review of the literature.

We describe ten cases of aortitis due to Salmonella that were treated at the University of Toronto-affiliated Hospitals between 1978 and 1997. Predisposing conditions included hypertension, diabetes mellitus, and myelodysplastic syndrome. Main presenting symptoms were fever and abdominal and back pain. The most frequent site involved was the abdominal aorta, followed by the thoracic aorta. All but one patient were treated with intravenous bactericidal antibiotics; seven also underwent surgery, four with axillobifemoral grafts and three with in situ grafts. Four of seven patients died within 1 month of the surgical procedure (three patients with in situ grafts and one patient with axillobifemoral graft). We also reviewed the pathogenesis, clinical and laboratory characteristics, and treatment of 140 cases of aortitis due to Salmonella reported in the literature since 1948. The use of bactericidal antibiotics, together with early surgical intervention and long-term suppressive antibiotic therapy, has led to improved survival.

An outbreak of Serratia marcescens infections related to contaminated chlorhexidine.

An outbreak of Serratia marcescens infections occurred in a university tertiary-care hospital. Alcohol-free chlorhexidine solutions were contaminated with S marcescens. The majority of patient and chlorhexidine strains had similar pulsed field-gel electrophoresis banding patterns. Chlorhexidine was recalled, and the rate of S marcescens isolation returned to baseline. Chlorhexidine without alcohol should not be used as an antiseptic.

Utility of serology in determining Helicobacter pylori eradication after therapy.

OBJECTIVE: To determine the usefulness of four serological tests in confirming cure of H pylori infection before the previously reported six-month post-treatment delay. PATIENTS AND METHODS: As part of a prospective, blinded, controlled trial, in which patients with duodenal ulcers were randomized to receive different combinations of antibiotics, serum samples were obtained in 89 patients before treatment, as well as on several occasions after treatment. Antibody titres were determined by ELISA with Bio-Rad immunoglobulin (Ig) A, Bio-Rad IgG, Pyloriset EIA-A for IgA and Pyloriset EIA-G for IgG. Eradication was confirmed with antral biopsy three months after therapy. RESULTS: The percentage drop in titre following treatment was significantly larger for the group of patients who were treated successfully with all four kits. Optimal cut-offs for identifying successful therapy were determined, and accuracy improved as the interval between testing and therapy was prolonged. Six months after therapy, the IgG test from Bio-Rad achieved 100% sensitivity and 80% specificity, and that from Pyloriset achieved 88% sensitivity and 100% specificity. At three months, however, test performance was quite good, with 90% sensitivity and 80% specificity when using a Pyloriset IgA titre drop of 20% or greater to predict successful eradication. CONCLUSION: Serology is a simple, easily available, noninvasive method that exhibits good positive predictive value in the confirmation of successful cure of H pylori infection three or six months after treatment.