Clinical trials in multiple sclerosis: past, present, and future.

For the past four decades, multiple sclerosis (MS) has been a focus for clinical trial development and execution. Advances in translational neuroimmunology have led to the development of effective disease-modifying therapies (DMTs) that greatly benefit patients with MS and mitigate their burden of disease. These achievements also stem from continued progress made in the definition and discovery of sensitive disease diagnostic criteria, objective disability assessment scales, precise imaging techniques, and disease-specific biomarkers. As a result, our knowledge of MS pathophysiology is more mature; the established clinical practice for the diagnosis and management of MS could serve as a roadmap to guide the development of more disease-specific interventions. In this article we briefly review the main achievements in the evolution of clinical trials for MS, and discuss opportunities for improvements.

Adverse event profile differences between rituximab and ocrelizumab: Findings from the FDA Adverse Event Reporting Database.

BACKGROUND: Rituximab and ocrelizumab are anti-CD20 monoclonal antibodies that have shown a marked reduction in multiple sclerosis (MS) inflammatory activity. However, their real-world safety profile has not been adequately compared. OBJECTIVE: To investigate the adverse event (AE) profile of rituximab and ocrelizumab reported to the Food and Drug Administration Adverse Event Reporting System (FAERS) database. METHODS: The FAERS database was filtered by indication (MS) and drug (rituximab or ocrelizumab). Disproportionality analyses including but not limited to reporting odds ratio (ROR) were conducted to identify drug-AE associations. A signal was detected if the lower limit of the 95% confidence interval of ROR (ROR025) exceeded 1. RESULTS: There were 623 and 7948 reports for rituximab and ocrelizumab, respectively. The most frequent AEs with rituximab and ocrelizumab were infusion-related reaction (4.82%) and urinary tract infection (10.52%), respectively. The strongest drug-AE association for rituximab and ocrelizumab were ear pruritus (ROR025: 47.53) and oral herpes (ROR025: 38.99), respectively. Ocrelizumab was associated with an almost two times higher frequency of infections than rituximab (21.93% vs 11.05%, respectively). CONCLUSION: This study revealed differences in reporting AEs between rituximab and ocrelizumab. Infections were reported more frequently with ocrelizumab. Although speculative, a potentially different or more extensive B-cell depletion by ocrelizumab might explain these findings. Additional pharmacovigilance studies need to be performed to better characterize differences in the AE profile in B-cell-depleting therapies.

Histopathological correlation of diffusion basis spectrum imaging metrics of a biopsy-proven inflammatory demyelinating brain lesion: A brief report.

Diffusion basis spectrum imaging (DBSI) models diffusion-weighted magnetic resonance imaging (MRI) signals as a combination of discrete anisotropic diffusion tensors and a spectrum of isotropic diffusion tensors. Here, we report the histopathological correlates of DBSI in the biopsied brain tissue of a patient with an inflammatory demyelinating lesion typical of multiple sclerosis (MS). Increased radial diffusivity (marker of demyelination), decreased fiber fraction (apparent axonal density), elevated nonrestricted isotropic fraction (marker of vasogenic edema), but unchanged axial diffusivity (marker of integrity of residual axons) seen in the lesion appeared consistent with histopathological findings of inflammatory demyelination with relative axonal sparing. Our report supports the application of DBSI as a biomarker in human studies of MS.

Natalizumab for Multiple Sclerosis: A Case in Point for the Impact of Translational Neuroimmunology.

Advances in translational neuroimmunology over the last two decades have revolutionized the treatment of relapsing forms of multiple sclerosis. A pathological hallmark of multiple sclerosis is the presence of leukocytes in the areas of disease activity in the CNS. Natalizumab inhibits the trafficking of lymphocytes from the blood into the brain and spinal cord by blocking the adhesion molecule α4-integrin. Representing the enormous success of a molecular targeted approach, natalizumab was the first mAb approved for the treatment of relapsing-remitting multiple sclerosis. However, only a few months after its approval, natalizumab was withdrawn from the market because of an unanticipated life threatening adverse effect: progressive multifocal leukoencephalopathy. Natalizumab was later reintroduced with required adherence to a strict monitoring program. In this article, we review the bench-to-bedside journey of natalizumab, along with the lessons learned from postmarketing studies.

Disability progression in aggressive multiple sclerosis.

OBJECTIVE: To examine disease progression in 'aggressive' multiple sclerosis (MS), British Columbia, Canada (1980-2009). METHODS: Aggressive (or 'malignant') MS was defined as Expanded Disability Status Scale (EDSS) ⩾6 within 5 years from onset. The first EDSS ⩾6 was termed 'baseline'. Within 2, 3 and 5 years post-baseline, patients were categorized as follows: 'worsened' or 'improved', relative to baseline EDSS (the remainder exhibited no change or had no new scores). The associations between patient characteristics (sex, relapsing onset/primary progressive, onset age, onset symptoms, disease duration, cumulative prior relapses and baseline EDSS) and worsening in disability were examined longitudinally using logistic regression. RESULTS: Of the 225/4341 (5.2%) aggressive/malignant MS patients, 134 (59.6%) were female, 167 (74.2%) were relapsing onset, 94 (41.8%) had received disease-modifying drugs at some point and the mean follow-up was 8.7 years. The proportion of patients who 'worsened' increased from 40.4% to 57.8%, while those who 'improved' varied little (range, 8.9%-10.2%). The odds of worsening increased with disease duration (adjusted odds ratio (AOR) = 1.36; 95% confidence interval (CI) = 1.22-1.52) and the presence of primary progressive (vs relapsing-onset) MS (AOR = 1.85; 95% CI = 1.01-3.38). CONCLUSION: Apart from disease duration and a primary progressive course, no clinically useful associations of subsequent disease worsening in patients with aggressive/malignant MS were identified.

Finger tapping impairments are highly sensitive for evaluating upper motor neuron lesions.

BACKGROUND: Identifying highly sensitive and reliable neurological exam components are crucial in recognizing clinical deficiencies. This study aimed to investigate finger tapping performance differences between patients with CNS demyelinating lesions and healthy control subjects. METHODS: Twenty-three patients with multiple sclerosis or clinically isolated syndrome with infratentorial and/or cervical cord lesions on MRI, and 12 healthy controls were videotaped while tapping the tip of the index finger against the tip and distal crease of the thumb using both the dominant and non-dominant hand. Videos were assessed independently by 10 evaluators (three MS neurologists, four neurology residents, three advanced practice providers). Sensitivity and inter-evaluator reliability of finger tapping interpretations were calculated. RESULTS: A total of 1400 evaluations (four videos per each of the 35 subjects evaluated by 10 independent providers) were obtained. Impairments in finger tapping against the distal thumb crease of the non-dominant hand, identified by neurologists, had the greatest sensitivity (84%, p < 0.001) for detecting impairment. Finger tapping against the thumb crease was more sensitive than the thumb tip across all categories of providers. The best inter-evaluator reliability was associated with neurologists' evaluations for the thumb crease of the non-dominant hand (kappa = 0.83, p < 0.001). CONCLUSIONS: Impaired finger tapping against the distal thumb crease of the non-dominant hand was a more sensitive technique for detecting impairments related to CNS demyelinating lesions. Our findings highlight the importance of precise examinations of the non-dominant side where impaired fine motor control secondary to an upper motor injury might be detectable earlier than the dominant side.

Marginal structural Cox models for estimating the association between ß-interferon exposure and disease progression in a multiple sclerosis cohort.

Longitudinal observational data are required to assess the association between exposure to ß-interferon medications and disease progression among relapsing-remitting multiple sclerosis (MS) patients in the "real-world" clinical practice setting. Marginal structural Cox models (MSCMs) can provide distinct advantages over traditional approaches by allowing adjustment for time-varying confounders such as MS relapses, as well as baseline characteristics, through the use of inverse probability weighting. We assessed the suitability of MSCMs to analyze data from a large cohort of 1,697 relapsing-remitting MS patients in British Columbia, Canada (1995-2008). In the context of this observational study, which spanned more than a decade and involved patients with a chronic yet fluctuating disease, the recently proposed "normalized stabilized" weights were found to be the most appropriate choice of weights. Using this model, no association between ß-interferon exposure and the hazard of disability progression was found (hazard ratio = 1.36, 95% confidence interval: 0.95, 1.94). For sensitivity analyses, truncated normalized unstabilized weights were used in additional MSCMs and to construct inverse probability weight-adjusted survival curves; the findings did not change. Additionally, qualitatively similar conclusions from approximation approaches to the weighted Cox model (i.e., MSCM) extend confidence in the findings.

Association between beta-interferon exposure and hospital events in multiple sclerosis.

PURPOSE: A systematic evaluation of hospital events can be an important surrogate measure for drug effectiveness or adverse effects. The purpose of this study was to examine the association between beta-interferon use and hospital events in a large cohort of patients with multiple sclerosis (MS). METHODS: Retrospective cohort study comparing beta-interferon exposed and unexposed patients using clinical data from the British Columbia MS (BCMS) database linked with health administrative databases, 1996-2008. For each patient, the primary outcome was the number of hospital events in each month, analyzed by quasi Poisson regression. Beta-interferon exposure was examined two ways: current and cumulative exposure. Secondary outcomes included whether a hospital event occurred in each month for each specific primary diagnoses, grouped by International Classification of Diseases categories. RESULTS: Current exposure to beta-interferon was not associated with an altered rate of hospital events (adjusted incident rate ratio 1.018; 95% CI 0.803-1.290). Similarly, there was no association with cumulative exposure. Cumulative beta-interferon exposure was associated with a lower odds of respiratory disease-related hospital events compared to those never exposed to beta-interferon. CONCLUSIONS: Exposure to beta-interferon for MS was not associated with a change in overall hospital event rates. Preliminary evidence suggests that the beta-interferons may have a protective effect against respiratory diseases requiring hospitalization in MS patients.

Exploring the association between weight loss-inducing medications and multiple sclerosis: insights from the FDA adverse event reporting system database.

Background: Several studies have demonstrated that early childhood and adolescent obesity are risk factors for multiple sclerosis (MS) susceptibility. Obesity is thought to share inflammatory components with MS through overproduction of pro-inflammatory adipokines (e.g., leptin) and reduction of anti-inflammatory adipokines (e.g, adiponectin). Recently, drug repurposing (i.e. identifying new indications for existing drugs) has garnered significant attention. The US Food and Drug Administration Adverse Event Reporting System (FAERS) database serves not only as a resource for mining adverse drug reactions and safety signals but also for identifying inverse associations and potential medication repurposing opportunities. Objective: We aimed to explore the association between weight-loss-inducing drugs and MS using real-world reports from the FAERS database. Design: Secondary analysis of existing data from the FAERS database. Methods: We conducted a disproportionality analysis using the FAERS database between the fourth quarter of 2003 and the second quarter of 2023 to explore associations between MS and weight loss-inducing drugs. Disproportionality was quantified using the reporting odds ratio (ROR). An inverse association was defined when the upper limit of the 95% confidence interval for ROR was <1. Results: We found an inverse association between MS and anti-diabetic weight loss-inducing drugs including semaglutide (ROR: 0.238; 95% CI: 0.132-0.429), dulaglutide (ROR: 0.165; 95% CI: 0.109-0.248), liraglutide (ROR: 0.161; 95% CI: 0.091-0.284), empagliflozin (ROR: 0.234; 95% CI: 0.146-0.377), and metformin (ROR: 0.387; 95% CI: 0.340-0.440). No inverse associations were found for other weight loss-inducing drugs such as phentermine, bupropion, topiramate, zonisamide, and amphetamine. An exception was naltrexone (ROR: 0.556; 95% CI: 0.384-0.806). Conclusion: Our findings suggest a potential consideration for repurposing anti-diabetic weight loss-inducing drugs including semaglutide, dulaglutide, and liraglutide (glucagon-like peptide-1 receptor agonists), empagliflozin (sodium-glucose cotransporter-2 inhibitor), and metformin (biguanide), for MS. This warrants validation through rigorous methodologies and prospective studies.

Characterising aggressive multiple sclerosis.

OBJECTIVE: To explore the occurrence and characteristics of aggressive multiple sclerosis (AMS) in adult-onset multiple sclerosis (MS) patients. METHODS: Prospectively collected data (1980-2009) from British Columbia, Canada, were retrospectively analysed. AMS was defined in three different ways (AMS1, 2 and 3): 'AMS1'--confirmed Expanded Disability Status Scale (EDSS) ≥ 6 within 5 years of MS onset; 'AMS2'--confirmed EDSS ≥ 6 by age 40; and 'AMS3'--secondary progressive MS within 3 years of a relapsing-onset course. Three respective 'non-aggressive' MS comparison cohorts were selected. Patients' characteristics were compared between aggressive and non-aggressive cohorts using multivariable logistic regression, with findings expressed as adjusted OR (AOR) and 95% CI. RESULTS: Application of the three definitions to the source population of 5891 patients resulted in 235/4285 (5.5%) patients fulfilling criteria for AMS1 (59.6% were female; 74.5% had relapsing-onset MS), 388/2762 (14.0%) for AMS2 (65.2% were female; 92.8% had relapsing-onset MS) and 195/4918 (4.0%) patients for AMS3 (61.0% were female). Compared to the respective control cohorts, those with AMS were more likely to be male (AOR=1.5, 95% CI 1.1 to 2.0 (AMS1); 1.6, 95% CI 1.3 to 2.1 (AMS2); 1.8, 95% CI 1.3 to 2.4 (AMS3)), older at MS symptom onset (AOR=1.1; 95% CI 1.1 to 1.1 (AMS1 and AMS3)) and have primary progressive MS (AOR=2.3, 95% CI 1.6 to 3.3 (AMS1); 2.7, 95% CI 1.7 to 4.4 (AMS2)). CONCLUSIONS: AMS was identified in 4-14% of patients, depending on the definition used. Although there was a relative preponderance of men and primary progressive MS presenting with AMS, the majority of patients were still women and those with relapsing-onset MS.

Oligoclonal bands and cerebrospinal fluid markers in multiple sclerosis: associations with disease course and progression.

BACKGROUND: The use of oligoclonal bands (OCBs) and cerebrospinal fluid (CSF) parameters are established in the diagnosis of MS, but poorly as markers of disease. OBJECTIVE: To investigate the role of OCBs in disease course and progression. METHODS: CSF data for 1120 patients with MS were analyzed for associations between OCBs and CSF parameters and clinical data (disease course [relapsing-onset MS (ROMS) vs primary-progressive MS (PPMS)]), disability progression (proportion reaching Expanded Disability Status Scale 6 within 10 years of onset and progression index) and ethnicity. RESULTS: Of patients with MS, 72.5% had detectable OCBs. For patients with detectable OCBs, 84.6% had ROMS and 15.4% PPMS versus 89.7% and 10.3%, respectively for those without detectable OCBs (p=0.04). Total CSF IgG and protein levels were higher in PPMS compared with ROMS (p<0.001). Disease progression appeared independent of OCB status. Patients with CSF (vs without) data were more likely to be male, older at onset, have PPMS and lack optic neuropathy at onset (p<0.001). CONCLUSIONS: OCB positivity and elevated total CSF IgG and protein were moderately associated with a PPMS disease course, but not disease progression. Patients with atypical clinical presentations were more likely to have had CSF work-up, suggesting a testing bias.

Disseminated Aspergillosis in a Patient With Neurosarcoidosis: Persistent Contrast Enhancement in CNS Despite Prolonged Antifungal Treatment: A Case Report.

A 56-year-old Caucasian man was diagnosed with definite neurosarcoidosis after he presented with progressive bilateral lower extremity weakness and dysesthesia. He was started on a combination immunosuppressant regimen of dexamethasone, methotrexate and infliximab. Two months into treatment with immunosuppressants, he developed devastating disseminated aspergillosis which clinically stabilized with aggressive antifungal treatment however had a protracted radiological course despite prolonged anti-fungal treatment for over two years. Interestingly, he remained in remission from neurosarcoidosis off immunosuppression during the same period. This case emphasizes need for vigilance for fungal infections in patients treated with combination immunosuppressive therapy particularly TNF-α inhibitors such as infliximab.

Temporal trends of disability progression in multiple sclerosis: findings from British Columbia, Canada (1975-2009).

BACKGROUND: Recent natural history studies suggest that multiple sclerosis (MS) is a more slowly progressing disease than previously thought. These observations are from studies separated by time, geography and methodological approach. OBJECTIVES: We investigated whether MS disease progression has changed over time in British Columbia, Canada. METHODS: The British Columbia MS database was queried for relapsing-onset MS patients with symptom onset from 1975 to <1995, first assessed within 15 years from onset and with at least two Expanded Disability Status Scale (EDSS) scores. Latest follow-up was to 2009. Patients were grouped by 5-year onset intervals (1975 to <1980, 1980 to <1985, 1985 to <1990, 1990 to <1995). Outcome was defined as time to reach sustained and confirmed EDSS 6 within 15 years of disease duration. Kaplan-Meier analysis was used to compare: the proportion of patients reaching EDSS 6 (primary analysis) and the time to EDSS 6 (secondary analysis) across the time-period groups. RESULTS: A total of 2236 relapsing-onset MS patients (73.4% female; mean age at onset: 32.3 ± 8.8 years) were included. No significant temporal trend was found in the proportion of patients reaching EDSS 6 within 15 years from onset (28.5%, 26.4%, 27.7%, 22.3% for intervals 1975 to <1980, 1980 to <1985, 1985 to <1990, 1990 to <1995, respectively; p = 0.09) or in survival curves for time to reach the outcome (p = 0.14). CONCLUSIONS: Rates of disease progression remained relatively stable over two decades of MS onset in British Columbia, Canada. Our results suggest that differences in disease progression findings between natural history studies may be related to factors other than time period.

Association between use of interferon beta and progression of disability in patients with relapsing-remitting multiple sclerosis.

CONTEXT: Interferon beta is widely prescribed to treat multiple sclerosis (MS); however, its relationship with disability progression has yet to be established. OBJECTIVE: To investigate the association between interferon beta exposure and disability progression in patients with relapsing-remitting MS. DESIGN, SETTING, AND PATIENTS: Retrospective cohort study based on prospectively collected data (1985-2008) from British Columbia, Canada. Patients with relapsing-remitting MS treated with interferon beta (n = 868) were compared with untreated contemporary (n = 829) and historical (n = 959) cohorts. MAIN OUTCOME MEASURES: The main outcome measure was time from interferon beta treatment eligibility (baseline) to a confirmed and sustained score of 6 (requiring a cane to walk 100 m; confirmed at >150 days with no measurable improvement) on the Expanded Disability Status Scale (EDSS) (range, 0-10, with higher scores indicating higher disability). A multivariable Cox regression model with interferon beta treatment included as a time-varying covariate was used to assess the hazard of disease progression associated with interferon beta treatment. Analyses also included propensity score adjustment to address confounding by indication. RESULTS: The median active follow-up times (first to last EDSS measurement) were as follows: for the interferon beta-treated cohort, 5.1 years (interquartile range [IQR], 3.0-7.0 years); for the contemporary control cohort, 4.0 years (IQR, 2.1-6.4 years); and for the historical control cohort, 10.8 years (IQR, 6.3-14.7 years). The observed outcome rates for reaching a sustained EDSS score of 6 were 10.8%, 5.3%, and 23.1% in the 3 cohorts, respectively. After adjustment for potential baseline confounders (sex, age, disease duration, and EDSS score), exposure to interferon beta was not associated with a statistically significant difference in the hazard of reaching an EDSS score of 6 when either the contemporary control cohort (hazard ratio, 1.30; 95% CI, 0.92-1.83; P = .14) or the historical control cohort (hazard ratio, 0.77; 95% CI, 0.58-1.02; P = .07) were considered. Further adjustment for comorbidities and socioeconomic status, where possible, did not change interpretations, and propensity score adjustment did not substantially change the results. CONCLUSION: Among patients with relapsing-remitting MS, administration of interferon beta was not associated with a reduction in progression of disability.

Anti-Neurofascin Antibodies Associated with White Matter Diseases of the Central Nervous System: A Red Flag or a Red Herring?

Autoantibodies against nodal and paranodal proteins, specifically anti-neurofascin antibodies (ANFAs), have been recently described in central and peripheral nervous system demyelinating disorders. We retrospectively reviewed the charts of six individuals evaluated at our Multiple Sclerosis Program who tested positive for serum ANFAs on Western blot. We describe these patients' clinical and diagnostic findings and attempt to identify features that might guide clinicians in checking for ANFAs. In our series, the women-to-men ratio was 2:1. At presentation, the median age was 60 years (range 30-70). The clinical presentation was pleiotropic and included incomplete transverse myelitis (n = 3), progressive myelopathy (n = 1), recurrent symmetric polyneuropathy (n = 1), and nonspecific neurological symptoms (n = 1). Atypical features prompting further workup included coexisting upper and lower motor neuron features, older age at presentation with active disease, atypical spinal cord MRI features, and unusual cerebrospinal fluid findings. The serum ANFAs panel was positive for the NF-155 isoform in five patients (IgM n = 2; IgG n = 2; both n = 1) and the NF-140 isoform in two (IgG n = 2). Larger studies are needed to assess the relevance of ANFAs in demyelinating nervous system diseases, their impact on long-term clinical outcomes, and associated therapeutic implications.

Lymphomatoid papulosis in a patient treated with glatiramer acetate and the glatiramoid Glatopa for multiple sclerosis: A case report.

A 48-year-old Caucasian woman with history of multiple sclerosis (MS) presented with erythematous papulonodular lesions in her extremities and trunk. She was being treated with glatiramer acetate (GA) for the past 10 years and the glatiramoid, Glatopa, for 2 years prior to this presentation. A skin biopsy showed CD30+ lymphoproliferative disorder consistent with lymphomatoid papulosis (LyP). Three weeks after stopping Glatopa, her skin lesions were improved. It remains unclear whether GA's or Glatopa's capability to alter T-cell differentiation, may have a link with LyP. This case report is a reminder to be vigilant for skin lesions in patients with MS.

Aging and efficacy of disease-modifying therapies in multiple sclerosis: a meta-analysis of clinical trials.

Background: Disease-modifying therapies (DMTs) for multiple sclerosis (MS) are approved for the treatment of disease activity and are effective in reducing relapses and new magnetic resonance imaging (MRI) lesions. However, disease activity generally subsides with time, and age-dependent changes in DMT efficacy are not well-established. We aimed to investigate whether age impacts the efficacy of DMTs in treating disease activity in patients with relapsing-remitting MS (RRMS). Methods: DMT efficacy related to age was assessed through a meta-analysis of clinical trials that evaluated the efficacy of DMTs in RRMS patients as measured by reductions in the annualized relapse rate (ARR), new T2 lesions, and gadolinium-enhanced lesions on MRI. Using the mean baseline patient age from each trial, a weighted linear regression was fitted to determine whether age was associated with treatment efficacy on a group level. Results: Group-level data from a total of 28,082 patients from 26 trials of 14 different DMTs were included in the meta-analysis. There were no statistically significant associations between age and reductions in ARR, new T2 lesions, and gadolinium-enhanced lesions of the treatment group compared with placebo. Conclusion: DMTs for RRMS show efficacy in treating disease activity independent of age as demonstrated by group-level data from DMT clinical trials. Nevertheless, clinical trials select for patients with baseline disease activity regardless of age, thereby not representing real-world patients with RRMS, where disease activity declines with age.

The association between handedness and clinicodemographic characteristics in people with multiple sclerosis: a brief report.

A relationship between handedness and clinicodemographic profiles of people with multiple sclerosis was sought using data from the Multiple Sclerosis Partners Advancing Technology Health Solutions network of 10 multiple sclerosis centers in the USA and Europe. Handedness data were available for 8888 multiple sclerosis patients, of which 917 (10.3%) were left-handed. Clinicodemographic profiles of right versus left-handed multiple sclerosis patients were similar except for a slightly increased proportion of men who were left-handed, and slightly reduced performance on the manual dexterity test using the non-dominant hand in left-handed patients. We found no evidence to suggest a prognostic implication of handedness in multiple sclerosis.

Diffusion basis spectrum imaging for identifying pathologies in MS subtypes.

Diffusion basis spectrum imaging (DBSI) combines discrete anisotropic diffusion tensors and the spectrum of isotropic diffusion tensors to model the underlying multiple sclerosis (MS) pathologies. We used clinical MS subtypes as a surrogate of underlying pathologies to assess DBSI as a biomarker of pathology in 55 individuals with MS. Restricted isotropic fraction (reflecting cellularity) and fiber fraction (representing apparent axonal density) were the most important DBSI metrics to classify MS using brain white matter lesions. These DBSI metrics outperformed lesion volume. When analyzing the normal-appearing corpus callosum, the most significant DBSI metrics were fiber fraction, radial diffusivity (reflecting myelination), and nonrestricted isotropic fraction (representing edema). This study provides preliminary evidence supporting the ability of DBSI as a potential noninvasive biomarker of MS neuropathology.

Antimicrobial resistance pattern of Gram-negative bacilli of nosocomial origin at 2 university hospitals in Iran.

The purpose of this study was to investigate the antimicrobial resistance pattern among common Gram-negative bacilli isolated from patients with nosocomial infection. A total of 200 samples of common Gram-negative bacilli (Klebsiella, Pseudomonas, Acinetobacter, and Escherichia coli) were collected from 2 university hospitals in Iran during a 1.5-year period from June 2004 to December 2005. All samples were examined for the antimicrobial activity of imipenem, cefepime, ciprofloxacin, ceftriaxone, and ceftazidime using E-test methods. The most frequent pathogens were Klebsiella spp. (38.5%) followed by Pseudomonas aeruginosa (28.5%), Acinetobacter spp. (20.5%), and E. coli (12.5%). The most active antibiotic was imipenem (84%). The susceptibility of the studied microorganisms was 25% for cefepime, 24% for ciprofloxacin, 20.5% for ceftazidime, and 11.8% for ceftriaxone. The susceptibility rates of Klebsiella to imipenem, cefepime, ciprofloxacin, ceftazidime, and ceftriaxone were 90.9%, 20.8%, 18.2%, 10.4%, and 5.2%, respectively. Likewise, these rates were 88%, 19%, 17%, 21%, and 21% for E. coli. Among Acinetobacter spp., the susceptibility rates were 77% for imipenem and 21% for ciprofloxacin. Among Pseudomonas, the rates were 75% for imipenem and 39% for ciprofloxacin. The antibiotics resistance among Gram-negative bacilli was widespread, so an antibiotic policy is urgently needed to delay the resistance development.