The effect of probiotics on the incidence of Clostridioides difficile: Retrospective cohort analysis

BACKGROUND

Conflicting evidence exists regarding probiotics and the incidence of Clostridioides difficile infection (CDI). This study evaluates whether probiotics are efficacious for CDI prophylaxis in patients receiving antibiotics.

METHODS

A retrospective cohort analysis of patients admitted to NYU Winthrop Hospital who received at least 1 dose of antibiotics considered high risk of inducing CDI. Patients were grouped according to probiotic use; association between probiotic use and incident CDI was examined. A model for incident CDI adjusting for known CDI risk factors was estimated.

RESULTS

Of 3,267 patients, 4.6% had CDI within 12 weeks of antibiotics initiation. A total of 5.1% received probiotics within 24 hours of initiation, and 6.6% initiated probiotics during the 12-week follow-up. Of those taking probiotics within 24 hours of antibiotics, 9.6% had CDI, and of those not taking probiotics 4.2% had CDI (relative risk, 2.3; 95% confidence interval, 1.4, 3.7). In time-dependent Cox models accounting for probiotic initiation and adjusting for potential confounders, a positive association between probiotics and CDI remained significant (hazard ratio, 2.7; P < .001).

DISCUSSION

Patients who received antibiotics with concurrent probiotics were more likely to have an incident of CDI compared with those who did not receive probiotics. Additional risk factors were histamine 2 receptor antagonists, proton pump inhibitors, and administration of multiple antibiotics simultaneously.

CONCLUSIONS

The present study, because of its large population and inclusion of multiple variables playing a role in CDI, serves as a valuable resource when considering efficacy of probiotics as CDI prophylaxis.

Lack of Pharmacokinetic Basis of Weight-Based Dosing and Intra-Operative Re-Dosing with Cefazolin Surgical Prophylaxis in Obese Patients: Implications for Antibiotic Stewardship

Traditionally, there have been uniform antibiotic dosing guidelines for prophylaxis for clean-clean-contaminated surgery in both non-obese and obese adults. All other factors predisposing to surgical site infections (SSIs) being equal, over time, the preferred drug is cefazolin. The usual dose, given immediately pre-procedure, has been 1 g intravenously (IV) in non-penicillin-allergic patients, which has been highly effective, Recently, it has become common practice to use high-dose cefazolin; i.e., 3 g IV, in obese patients. This article reviews the literature on high-dose cefazolin prophylactic regimens in the obese from a pharmacokinetic (PK) point of view. There are no comparative studies to support this approach, which is based largely on the theory "more must be better." Weight-based dosing of cefazolin in the obese is flawed, because it does not take into account PK factors, which are critical in the obese. Cefazolin is a water-soluble (hydrophilic) antibiotic that does not penetrate adipose tissue regardless of IV dose. Importantly, adipose tissue is not a valid target tissue in clean-clean-contaminated SSI prophylaxis, as it does not become infected. Higher doses result in proportionately higher serum/non-adipose tissue concentrations, but adipose tissue concentrations are unaffected. Cefazolin displays time-dependent killing kinetics so that as long as serum/tissue concentrations are above the minimum inhibitory concentration (MIC) of SSI pathogens, there is no enhanced killing with higher concentrations relative to concentration-dependent antibiotics. Taking into account PK principles, a cefazolin 1 g IV bolus results in peak serum concentrations of ∼185 mcg/mL, provides at least six hours of intra-operative protection, aside from any post-antibiotic effects, and eliminates any rationale for intra-operative re-dosing for procedures lasting six hours or less. Some have argued that a cefazolin 3 g IV dose in the obese does not matter, as more must necessarily be better. However, from an antibiotic stewardship program (ASP) perspective, unneeded antibiotics are unnecessary. Moreover, the costs of cefazolin 1 g (IV push) at $0.75 versus 2 g (IV piggyback) at $ 6.83 can be significant in large centers using cefazolin prophylaxis for cardiothoracic, orthopedic, obstetric/gynecology, and bariatric surgery. Excessive antibiotics also expose the patient to potential adverse effects; i.e., Clostridium difficile. There is no dose-dependent or duration of exposure effect on resistance with one or two pre-operative or intra-operative doses. Well-done PK-based studies in obese patients clearly demonstrate the lack of benefit of using a 3-g dose or intra-operative re-dosing and show no incremental increase in adipose tissue concentrations with high doses. From an ASP point of view, antibiotic dosing recommendations should be reviewed and revised on the basis of PK principles that indicate that weight-based dosing has no basis for pre-operative prophylaxis in obese patients.

HIV adult with fever and shortness of breath: Influenza B misdiagnosed as Pneumocystis (carinii) jiroveci pneumonia (PCP)

Clinical correlation is essential in assessing the relevance of the patient's history and physical findings in making a clinical presumptive diagnosis. False diagnostic associations may result in misdiagnosis. We present a case of an elderly female with HIV on HAART who presented with shortness of breath assumed to have Pneumocystis (carinii) jiroveci pneumonia (PCP) even though she had a clinical diagnosis of influenza B. She was thought to have PCP only because she had HIV. Tests for PCP were negative including BAL staining. Influenza B present in her respiratory secretions by PCR and was also cultured from BAL fluid. Diagnostic associations are helpful in suggesting diagnostic possibilities but must be supported by clinical correlation of characteristic clinical features.

Legionnaire's disease presenting with encephalitis, myoclonus, and seizures: Successful treatment with doxycycline

Legionnaire’s disease (LD) is a non-zoonotic atypical community acquired pneumonia (CAP) with several characteristic extra-pulmonary findings. Pending diagnostic test results, selected characteristic findings when considered together are the basis of clinical syndromic diagnosis and the basis of empiric antimicrobial therapy. Of the extra-pulmonary manifestation of LD, neurologic findings are among the most common, e.g., headache, mental confusion. In LD, encephalitis is rare as are myoclonus and seizures.

This is a most interesting case of LD that presented with encephalitis, myoclonus and seizures. Pulmonary infiltrates developed early after admission. LD was suspected on the basis of otherwise unexplained characteristic findings, e.g., hypophosphatemia, elevated serum transaminases, microscopic hematuria, elevated ferritin, and empiric doxycycline therapy was started. The diagnosis of LD was further supported by prominent and persistent myoclonus and seizures, rare but characteristic neurologic findings in LD.

On week 12 of hospitalization, he finally seroconverted with negative urinary antigen tests indicating his LD was due to a non-L. pneumophilia (serotype 01) strain. On doxycycline, he made a slow but complete recovery. We believe this is the first reported case of LD presenting with encephalitis, myoclonus, and seizures successfully treated with doxycycline.

514. The Effect of Probiotics on the Incidence of Clostridium difficile

Background

Currently there is conflicting evidence regarding probiotics affecting the incidence and/or severity of Clostridium difficile infection (CDI). According to the IDSA guidelines, there are insufficient data to support the use of probiotics as primary prophylaxis of CDI. The primary objective of this study was to evaluate whether the administration of probiotics is efficacious for CDI prophylaxis in patients who are on antibiotics making them at increased risk for contracting CDI.

Methods

The study is an Institutional Review Board approved retrospective cohort study looking at patients who were admitted to NYU Winthrop University Hospital and received at least one dose of antibiotics considered high-risk of inducing CDI. Patients were grouped according to concurrent probiotic use and the association between probiotic use and incident CDI was examined. A model for incident CDI adjusting for number of concurrent antibiotics, patient age, proton pump inhibitors, histamine receptor antagonists, presence of colitis, and chemotherapy was also estimated. Microbiology reports were analyzed for up to 12 weeks post initial administration of antibiotics to determine whether patient acquired CDI. If no CDI occurred during the admission or post discharge, data was censored at 12 weeks.

Results

Of 2,208 patients, 1,502 (68%) were included in the interim analysis. Ninety-six out of 1,502 patients (6.39%) had CDI within 12 weeks of antibiotics initiation. One hundred thirty-five (9%) were on probiotics during antibiotic use and 1,367 (91%) were not. Of those taking probiotics, 11.1% had an incident of CDI and of those not taking probiotics, 5.9% had an incident of CDI with a relative risk of 1.88 (1.11, 3.16) and a P = 0.02. After adjustment, although a positive association between probiotics and CDI was still observed, it was not statistically significant (P = 0.24)

Conclusion

Based on the interim analysis, probiotics were associated with a higher risk of CDI in univariate analysis, however, when adjusted for several confounding factors this association, while still positive, was no longer statistically significant.Further data collection is ongoing to corroborate these results.

Disclosures

All authors: No reported disclosures.

How safe is doxycycline for young children or for pregnant or breastfeeding women?

Tetracycline antimicrobials entered into clinical usage in the late 1940s. Permanent dental staining from tetracyclines was first appreciated in 1956, eventually leading to avoidance of this class of antibiotics whenever possible in young children and pregnant or breastfeeding women. Doxycycline, introduced in 1967, binds calcium less avidly than prior tetracyclines and is regarded by some authorities as safe to prescribe for pregnant women and young children. Review of the available data, however, suggests that this interpretation may be incorrect or at least premature. In conclusion, until more definitive data are developed, doxycycline should continue to be only selectively prescribed for young children and pregnant or breastfeeding women for whom alternative, safer antibiotics are not available, and courses of treatment should be of as short a duration as possible.

Intracranial complications of acute bacterial endocarditis

Background:

Infectious endocarditis (IE) clinically manifests as either subacute bacterial endocarditis (SBE) or acute bacterial endocarditis (ABE). Neurologic manifestations are markedly different for these two entities. ABE is caused by invasive, highly virulent pathogens (e.g., Staphylococcus aureus), whereas SBE is attributed to relatively avirulent, non-invasive organisms (e.g., viridans streptococci).

Methods:

Here, we reviewed the clinical and radiographic presentations of a patient with cranial complications attributed to ABE. Such patients typically develop central nervous system (CNS) septic emboli resulting in stroke (with/without intracranial hemorrhage (ICH)) and/or mycotic aneurysms resulting in ICH bleeds.

Results:

With ABE, cerebrospinal fluid (CSF) seeding may result in acute bacterial meningitis (ABM), documented by positive Gram stain and/or culture for S. aureus, decreased glucose, highly elevated lactose acid levels, or ICH. Alternatively, in SBE, the CSF profile reflects an aseptic (viral) meningitis (i.e., Gram stain and culture negative, a normal glucose, and lymphocytic pleocytosis), while septic microemboli to the vasa vasorum contribute to an inflammatory reaction in the adventitia/muscle layer that weakens the vessel wall and results in mycotic aneurysms that may leak but often do not rupture causing ICH.

Conclusion:

Here, we reviewed the literature for intracranial pathology accompanying ABE versus SBE. ABE typically results in acute ischemia, septic emboli, stroke/hemorrhagic infarcts, or ICH. SBE more classically produces septic microemboli and mycotic aneurysms that may leak, but rarely producing ICH. We also presented a patient with ABE attributed to S. aureus whose septic emboli/stroke was accompanied by a mycotic aneurysm; the ruptured resulting in a large right occipital ICH.

A rare case of influenza A in a hospitalized adult presenting with encephalitis and a seizure

Influenza A in hospitalized adults uncommonly may present with neurologic manifestations, e.g., encephalitis. Encephalitis is the most common influenza related neurologic complication in adults, However, seizures in hospitalized adults due to influenza are extremely rare. This is a case of a 58 year old female hospitalized for influenza A. On admission, she was confused and obtunded. Her EEG showed diffuse global slowing indicative of encephalitis. On hospital day (HD) #2, she had a seizure. She had no history of a seizure disorder, and was not febrile at the time of the seizure. While seizures are not uncommon in children (febrile seizures) with influenza B, but in adults with influenza A, only a few cases of seizures have been reported. This case was most interesting in having both encephalitis and seizure complicating influenza A. If present, neuropsychiatric manifestations may be due to ostelamivir, but encephalitis and seizures are not among the neurologic adverse effects of ostelamivir. In adults hospitalized with influenza A, clinicians should be alert to the possibility of neurologic complications.

Enhanced Efficacy of High Dose Oral Vancomycin Therapy in Clostridium difficile Diarrhea for Hospitalized Adults Not Responsive to Conventional Oral Vancomycin Therapy: Antibiotic Stewardship Implications

Current therapy of Clostridium difficile diarrhea (CDD) is problematic. Optimal treatment for CDD remains oral vancomycin, but there is little data on oral vancomycin dosing regimens. The objective of this C. difficile diarrhea study was to compare the efficacy of "high dose" vancomycin, 500 mg (PO) q6h, as sole treatment and in those who after 72 h failed to respond to conventional doses of oral vancomycin, 125-250 mg (PO) q6h. Hospitalized adults with CDD were evaluated by various oral vancomycin regimens, i.e., a conventional dose group (125-250 mg (PO) q6h), a "high dose escalation" dose group (250 mg → 500 mg (PO) q6h), and a "high dose" group (500 mg (PO) q6h). Oral vancomycin treatment groups were compared by time to improvement, i.e., decrease in >50% of watery stools/day and duration of therapy. The high dose escalation and high dose oral vancomycin groups showed the most rapid resolution of diarrhea. There was marked decrease in stools/day after "high dose" vancomycin escalation from conventional dosing, i.e., 250 mg (PO) q6h → 500 mg (PO) q6h. This study demonstrated that "high dose" escalation or initial high dose oral vancomycin, i.e., 500 mg (PO) q6h was the most efficacious regimen for CDD.

Lyme carditis with isolated left bundle branch block and myocarditis successfully treated with oral doxycycline

Lyme disease may present with a variety of cardiac manifestations ranging from first degree to third degree heart block. Cardiac involvement with Lyme disease may be asymptomatic, or symptomatic. Atrioventrical conduction abnormalities are the most common manifestation of Lyme carditis. Less common, are alternating right bundle branch block (RBBB) and left bundle branch block (LBBB). We present an interesting case of a young male whose main manifestation of Lyme carditis was isolated LBBB. He also had mild Lyme myocarditis. The patient was successfully treated with oral doxycycline, and his isolated LBBB and myocarditis rapidly resolved.

Acute Encephalitis in an Adult with Diffuse Large B-Cell Lymphoma with Secondary Involvement of the Central Nervous System: Infectious or Non-Infectious Etiology?

Both infectious and non-infectious etiologies of acute encephalitis have been described, as well as their specific presentations, diagnostic tests, and therapies. Classic findings of acute encephalitis include altered mental status, fever, and new lesions on neuroimaging or electroencephalogram (EEG). We report an interesting case of a 61-year-old male with a history of diffuse large B-cell lymphoma with secondary involvement of the central nervous system (SCNS-DLBCL). He presented with acute encephalitis: altered mental status, fever, leukocytosis, neuropsychiatric symptoms, multiple unchanged brain lesions on computed tomography scan of the head, and EEG showed mild to moderate diffuse slowing with low-moderate polymorphic delta and theta activity. With such a wide range of symptoms, the differential diagnosis included paraneoplastic and autoimmune encephalitis. Infectious and autoimmune/paraneoplastic encephalitis in patients with SCNS-DLBCL are not well documented in the literature, hence diagnosis and therapy becomes challenging. This case report describes the patient’s unique presentation of acute encephalitis.

Legionnaire's Disease: A Clinical Diagnostic Approach

Legionnaire's disease is a nonzoonotic atypical pneumonia caused by Legionella sp that occurs sporadically or in outbreaks. Legionnaire's disease pneumonia is accompanied by several extrapulmonary clinical and laboratory findings. Rather than testing all pneumonias for Legionnaire's disease, the clinical challenge is to recognize the diagnostic significance of Legionnaire's disease's. The pretest probability of Legionnaire's disease is increased if several characteristic extrapulmonary findings are present. Similarly, if certain key findings are absent, Legionnaire's disease may be eliminated from further diagnostic consideration. If characteristic clinical findings are present, then specific tests should be ordered to confirm or rule out Legionnaire's disease.

Legionnaire's Disease and its Mimics: A Clinical Perspective

Whenever the cardinal manifestations of a disorder occur in similar disorders, there is potential for a disease mimic. Legionnaire's disease has protean manifestations and has the potential to mimic or be mimicked by other community acquired pneumonias (CAPs). In CAPs caused by other than Legionella species, the more characteristic features in common with legionnaire's disease the more difficult the diagnostic conundrum. In hospitalized adults with CAP, legionnaire's disease may mimic influenza or other viral pneumonias. Of the bacterial causes of CAP, psittacosis and Q fever, but not tularemia, are frequent mimics of legionnaire's disease.

Sarcoidosis with fever and a splenic infarct due to CMV or lymphoma?

We present a case of an adult female with a past history of pulmonary sarcoidosis who presented with fever, night sweats, profound fatigue, and LUQ abdominal pain. Sarcoidosis is an afebrile disorder (excluding Lofgren's syndrome, Heerfordt's syndrome or neurosarcoidosis). Therefore, the presence of fever with sarcoidosis should suggest infection, usually viral, or lymphoma. Sarcoidosis-lymphoma syndrome describes the evolution of a lymphoma in long standing sarcoidosis. Fever aside, possible lymphoma is suggested by otherwise unexplained fever, pleural unilateral effusion, highly elevated ESR or ferritin levels. In this case, a viral etiology was suggested because of atypical lymphocytosis and mildly elevated transaminases. In this patient, CMV IgM titers and elevated CMV PCR viral load confirmed the diagnosis of CMV infectious mononucleosis with lung and liver involvement. In this case CMV infectious mononucleosis was accompanied by procoagulant activity which resulted a DVT, pulmonary emboli and splenic infarct. We believe this to be the first reported case of CMV infectious mononucleosis splenic infarct in a patient with a history of sarcoidosis.

Viral influenza-like illnesses: dynamic interrelationships during the 2015-2016 influenza season in hospitalized patients

In hospitalized children and adults, the temporal relationship of viruses causing influenza-like illnesses (ILIs) and influenza has not been well described. During the 2015-2016 influenza season at our hospital, the dynamic interrelationships between ILI viruses (human metapneumovirus, respiratory syncytial virus, human parainfluenza viruses 3 and 4, rhinoviruses/enteroviruses, and coronaviruses) and influenza A were characterized in 768 hospitalized children and adults.

Burkholderia contaminans Colonization from Contaminated Liquid Docusate (Colace) in a Immunocompetent Adult with Legionnaire's Disease: Infection Control Implications and the Potential Role of Candida pellucosa

Objective:B. contaminans was cultured from respiratory secretions and liquid docusate (Colace) in a Neurosurgical Intensive Care Unit (NICU) patient with community-acquired Legionnaire’s disease but not from another bottle given to the patient. Unexpectedly, C. pelliculosa was cultured from two bottles, but not the B. contaminans bottle or respiratory secretions. Methods:B. cepacia, later identified as B. contaminans, was cultured from a bottle of liquid docusate (Colace) dispensed to a non-cystic fibrosis patient. His respiratory secretions were colonized with B. contaminans. Results: Eradication of B. contaminans colonization in the patient’s respiratory secretions was attempted. With levofloxacin, B. contaminans developed multidrug resistance (MDR). Subsequent TMP-SMX therapy did not result in further MDR. Nine other ICU patients were given docusate from the same lot, but there were no other B. contaminans isolates. Conclusion:B. contaminans colonization of respiratory secretion may be difficult to eliminate. The significance of C. pelliculosa cultured from liquid docusate (Colace) remains to be elucidated. In this case, it appeared that B. contaminans may have inhibited the growth of C. pelliculosa in the same bottle. Others should be alerted to the possibility that C. pelliculosa may be present in B. contaminans–contaminated lots of liquid docusate (Colace).

Diagnostic dilemma: Epstein-Barr virus (EBV) infectious mononucleosis with lung involvement or co-infection with Legionnaire's disease?

BACKGROUND

Hospitalized adults with fever and "pneumonia" can be a difficult diagnostic challenge particularly when the clinical findings may be due to different infectious diseases.

METHODS

We recently had an elderly female who presented with fever, fatigue and dry cough with elevated serum transaminases and lung infiltrates. The diagnosis of Epstein-Barr virus (EBV) infectious mononucleosis (IM) was made based on a positive Monospot test, elevated EBV VCA IgM titer, and highly elevated EBV viral load. Her chest infiltrates were not accompanied by hilar adenopathy which may occur with EBV IM. Her dry cough persisted and she developed abdominal pain.

RESULTS

Legionnaire's disease was considered because she had extra-pulmonary findings characteristic of Legionnaire's disease, e.g., relative bradycardia, abdominal pain, hyponatremia, hypophosphatemia, elevated ferritin levels, microscopic hematuria. Legionella titers were negative, but Legionella (serogroup 1) urinary antigen was positive.

CONCLUSIONS

We present a diagnostic dilemma in an elderly female with both Legionnaire's disease and Epstein-Barr virus infectious mononucleosis with pulmonary involvement.

Chikungunya fever presenting with protracted severe pruritus

Travelers returning from the tropics often present with rash/fever. Those with rash/fever and myalgias/arthralgias are most likely due to chikungunya fever, dengue fever, or Zika virus. In these arthropod viral transmitted infections, the rash may be pruritic. The case presented here is that of chikungunya fever remarkable for the intensity and duration of her pruritis.

Coxsackie B5 infection in an adult with fever, truncal rash, diarrhea and splenomegaly with highly elevated ferritin levels

Coxsackie viruses are enteroviruses most common in children. Coxsackie B viral infections often present with biphasic fever, headache, pharyngitis, nausea/vomiting, diarrhea and a maculopapular rash that spares the palms and soles. These clinical features may be present in other viral infections. We present a case of a hospitalized adult with rash and fever with highly elevated ferritin levels later found to be due to Coxsackie B5. We believe this is the first case of Coxsackie B infection with otherwise unexplained highly elevated ferritin levels.

Fever in a traveler returning from the Amazon. Do not forget hepatitis A

Travelers returning from the tropics with fever remain a diagnostic challenge. Fever and chills suggest malaria, but may be present in dengue, chikungunya and influenza, and splenomegaly favors malaria or typhoid fever. In terms of laboratory tests, leukopenia suggests dengue fever, chikungunya fever or influenza. Atypical lymphocytes are present in malaria, dengue fever, chikungunya fever and influenza HAV, but not typhoid fever. Thrombocytopenia is profound in dengue fever, is also present in influenza and malaria. Mildly increased serum transaminases are common in malaria, typhoid fever, dengue fever, chikungunya fever and influenza while very high serum transaminases point to HAV. We present a case of a young woman traveler returning from the Amazon with splenomegaly, leukopenia, atypical lymphocytes, elevated LDH and minimally elevated serum transaminases who was found to have acute hepatitis A infection.

Adult human metapneumonovirus (hMPV) pneumonia mimicking Legionnaire's disease

In adults hospitalized with viral pneumonias the main differential diagnostic consideration is influenza pneumonia. The respiratory viruses causing viral influenza like illnesses (ILIs), e.g., RSV may closely resemble influenza. Rarely, extrapulmonary findings of some ILIs may resemble Legionnaire's disease (LD), e.g., adenovirus, human parainfluenza virus (HPIV-3). We present a most unusual case of human metapneumonovirus pneumonia (hMPV) with some characteristic extrapulmonary findings characteristic of LD, e.g., relative bradycardia, as well as mildly elevated serum transaminases and hyphosphatemia. We believe this is the first reported case of hMPV pneumonia in a hospitalized adult that had some features of LD.

A Case of Pneumonia Caused by Pneumocystis Jirovecii and Cryptococcus Neoformans in a Patient with HTLV-1 Associated Adult T- Cell Leukemia/Lymphoma: Occam's Razor Blunted

Adult T-cell leukemia/lymphoma (ATLL) is usually preceded by infection with human T-cell lymphotropic virus I (HTLV-I). Patients with ATLL frequently get opportunistic infections of the lungs, intestines, and central nervous system. Pneumocystis pneumonia is commonly known as an AIDS defining illness. Grocott's methenamine silver stain of bronchoalveolar lavage (BAL) samples obtained via bronchoscopy remain the gold standard for diagnosis. Pulmonary cryptococcosis is seen in patients with T-cell deficiencies and a diagnosis is made by culture of sputum, BAL, or occasionally of pleural fluid. We present the second case of coinfection with these two organisms in a patient with ATLL who was successfully treated with trimethoprim-sulfamethoxazole, corticosteroids, and fluconazole. We illustrate the need for high clinical vigilance for seeking out an additional diagnosis, especially in immunocompromised patients if they are not improving despite receiving appropriate treatment.

Legionnaires' disease

Since first identified in early 1977, bacteria of the genus Legionella are recognised as a common cause of community-acquired pneumonia and a rare cause of hospital-acquired pneumonia. Legionella bacteria multisystem manifestations mainly affect susceptible patients as a result of age, underlying debilitating conditions, or immunosuppression. Water is the major natural reservoir for Legionella, and the pathogen is found in many different natural and artificial aquatic environments such as cooling towers or water systems in buildings, including hospitals. The term given to the severe pneumonia and systemic infection caused by Legionella bacteria is Legionnaires' disease. Over time, the prevalence of legionellosis or Legionnaires' disease has risen, which might indicate a greater awareness and reporting of the disease. Advances in microbiology have led to a better understanding of the ecological niches and pathogenesis of the condition. Legionnaires' disease is not always suspected because of its non-specific symptoms, and the diagnostic tests routinely available do not offer the desired sensitivity. However, effective antibiotics are available. Disease notification systems provide the basis for initiating investigations and limiting the scale and recurrence of outbreaks. This report reviews our current understanding of this disease.

Fever of unknown origin: a clinical approach

Fevers of unknown origin remain one of the most difficult diagnostic challenges in medicine. Because fever of unknown origin may be caused by over 200 malignant/neoplastic, infectious, rheumatic/inflammatory, and miscellaneous disorders, clinicians often order non-clue-based imaging and specific testing early in the fever of unknown origin work-up, which may be inefficient/misleading. Unlike most other fever-of-unknown-origin reviews, this article presents a clinical approach. Characteristic history and physical examination findings together with key nonspecific test abnormalities are the basis for a focused clue-directed fever of unknown origin work-up.