Postobstructive Pneumonia: An Underdescribed Syndrome.

BACKGROUND: Postobstructive community-acquired pneumonia (PO-CAP) is relatively common in clinical practice. The clinical syndrome is poorly defined, and the role of infection as a cause of the infiltrate is uncertain. We prospectively studied patients with PO-CAP and compared them to a cohort of patients with bacterial community-acquired pneumonia (B-CAP). METHODS: We prospectively studied patients hospitalized for CAP; 5.4% had PO-CAP, defined as a pulmonary infiltrate occurring distal to an obstructed bronchus. Sputum and blood cultures, viral polymerase chain reaction, urinary antigen tests, and serum procalcitonin (PCT) were done in nearly all cases. Clinical and laboratory characteristics of patients with PO-CAP were compared to those of patients with B-CAP. RESULTS: In a 2-year period, we identified 30 patients with PO-CAP. Compared to patients with B-CAP, patients with PO-CAP had longer duration of symptoms (median, 14 vs 5 days;P< .001). Weight loss and cavitary lesions were more common (P< .01 for both comparisons) and leukocytosis was less common (P< .01) in patients with PO-CAP. A bacterial pathogen was implicated in only 3 (10%) PO-CAP cases. PCT was <0.25 ng/mL in 19 (63.3%) patients. Although no differences were observed in disease severity or rates of intensive care unit admissions, 30-day mortality was significantly higher in PO-CAP vs B-CAP (40.0% vs 11.7%;P< .01). CONCLUSIONS: Although there is substantial overlap, PO-CAP is a clinical entity distinct from B-CAP; a bacterial cause was identified in only 10% of patients. Our study has important implications for the clinical recognition of patients with PO-CAP, the role of microorganisms as etiologic agents, and the use of antibiotic therapy.

Clinical Diagnosis, Viral PCR, and Antibiotic Utilization in Community-Acquired Pneumonia.

We evaluated the intensity of antibiotic therapy in patients in whom the etiology of community-acquired pneumonia (CAP) was determined using newly available diagnostic techniques. For 1 year, we studied all patients admitted for findings consistent with CAP. Sputum and blood cultures, urinary pneumococcal and Legionella antigens, and viral polymerase chain reaction (PCR) were studied prospectively. Patients were stratified based on the final diagnoses: proven bacterial, presumptive bacterial, viral, fungal, undetermined, and uninfected. We determined the number of antibiotics given, duration of antibiotic therapy, and intensity of antibiotic use determined by antibiotic-days defined as the sum, in each patient, of all antibiotics given for CAP and the number of days given. Median duration and intensity of antibiotics were 12 and 18 days for proven, and 13 and 16.5 days for presumed bacterial CAP (P > 0.9). When positive viral PCR results were not disclosed to primary care physicians, antibiotic use was similar to that in bacterial CAP. However, in 11 cases, when positive viral PCR results were disclosed, duration and intensity of antibiotic use were reduced to 7 and 9 days, respectively (P = 0.05 and 0.08, respectively). Antibiotic use was similar in patients with bacterial pneumonia and those judged on clinical grounds to have likely nonbacterial infection. Despite obvious differences in clinical syndromes and final diagnoses, the intensity of antibiotic therapy was similar in all groups of patients admitted for CAP with the exception of those who were uninfected and whose primary care physicians were informed of a positive viral PCR.

Use of string test and stool specimens to diagnose pulmonary tuberculosis.

BACKGROUND: The Xpert MTB/RIF (MTB/RIF) test has advanced the field of tuberculosis (TB) diagnostics; however, depending on age and HIV status, 10-85% of individuals with presumed pulmonary TB (PTB) are unable to produce sputum. METHODS: The feasibility of using MTB/RIF and culture on stool and string test specimens from 13 adult patients with presumed PTB was studied. RESULTS: The string test was well tolerated with a median Wong Baker Faces score of 2. The string test had 100% sensitivity and specificity by MTB/RIF and 87.5% sensitivity and 100% specificity by culture. In stool, Mycobacterium tuberculosis DNA was detected in all cases of culture-confirmed PTB. CONCLUSION: The string test and stool provide diagnostic specimens that warrant further investigation.

Aerococcal infection at three US Tertiary Care Hospitals.

OBJECTIVES: The aim of the present study was to determine clinical features of Aerococcus infections and the significance of the Aerococcus species isolated from any clinical samples. METHODS: Electronic records of all cultures yielding Aerococcus species from 2002 to 2012 were obtained from three tertiary care hospitals. We performed an in-depth review of medical records. RESULTS: Aerococcus was isolated from ≥ 1 site in 93 patients. Blood cultures were positive in 64 patients; 15 with definite bacteremia, including 3 with endocarditis, 7 with urinary tract infections, 13 with probable bacteremia, and 36 in which Aerococcus was judged to be a possible contaminant. Of 19 urine isolates, 10 were from patients with symptomatic urinary tract infections and 7 were from patients with asymptomatic bacteriuria; in 2 cases, urine isolates were regarded as possible contaminants. Most patients with urinary isolates had underlying urological abnormalities. Other sources for Aerococcus included synovial fluid, bile, bone, intraabdominal abscess, and ovarian abscess. All of the isolates tested with ampicillin, cefazolin, clindamycin, and vancomycin were susceptible. A total of two patients with definite Aerococcus infection died, but all of the others responded to antibiotic therapy. CONCLUSIONS: Aerococcus often is considered a contaminant; however, in our case series, 35% of cases in which Aerococcus was isolated from any site indicated a definite infection. In patients with positive blood cultures for Aerococcus, at least 23% were associated with infection. Appropriate attention needs to be directed to Aerococcus when it is isolated from a normally sterile site.

Trypanosoma cruzi meningoencephalitis in a patient with acquired immunodeficiency syndrome.

As a result of global migration, a significant number of people with Trypanosoma cruzi infection now live in the United States, Canada, many countries in Europe, and other non-endemic countries. Trypanosoma cruzi meningoencephalitis is a rare cause of ring-enhancing lesions in patients with acquired immunodeficiency syndrome (AIDS) that can closely mimic central nervous system (CNS) toxoplasmosis. We report a case of CNS Chagas reactivation in an AIDS patient successfully treated with benznidazole and antiretroviral therapy in the United States.

Cutaneous leishmaniasis in Cuban immigrants to Texas who traveled through the Darién Jungle, Panama.

Cutaneous leishmaniasis is rarely seen in the United States. Four Cuban immigrants traveled along the same route at different times from Cuba to Ecuador, then northward, including through the Darién Jungle in Panama. These patients had chronic ulcerative non-healing skin lesions and were given a diagnosis of leishmaniasis.

Can an etiologic agent be identified in adults who are hospitalized for community-acquired pneumonia: results of a one-year study.

INTRODUCTION: Determining the cause of community-acquired pneumonia (CAP) remains problematic. In this observational study, we systematically applied currently approved diagnostic techniques in patients hospitalized for CAP in order to determine the proportion in which an etiological agent could be identified. METHODS: All patients admitted with findings consistent with CAP were included. Sputum and blood cultures, urine tests for pneumococcal and Legionella antigens, nasopharyngeal swab for viral PCR, and serum procalcitonin were obtained in nearly every case. Admission-related electronic medical records were reviewed in entirety. RESULTS: By final clinical diagnosis, 44 patients (17.0%) were uninfected. A causative bacterium was identified in only 60 (23.2%) cases. PCR identified a respiratory virus in 42 (16.2%), 12 with documented bacterial coinfection. In 119 (45.9%), no cause for CAP was found; 69 (26.6%) of these had a syndrome indistinguishable from bacterial pneumonia. Procalcitonin was elevated in patients with bacterial infection and low in uninfected patients or those with viral infection, but with substantial overlap. CONCLUSIONS: Only 23.2% of 259 patients admitted with a CAP syndrome had documented bacterial infection; another 26.6% had no identified bacterial etiology, but findings closely resembled those of bacterial infection. Nevertheless, all 259 received antibacterial therapy. Careful attention to the clinical picture may identify uninfected patients or those with viral infection, perhaps with reassurance by a non-elevated procalcitonin. Determining an etiologic diagnosis remains elusive. Better discriminators of bacterial infection are sorely needed.

IRIS iQ200 workstation as a screen for performing urine culture.

We cultured 1000 urines and tested them with the iQ200 Workstation (Iris Diagnostics, Chatsworth, CA, and Arkray, Edina, MN, USA) for leukocyte esterase and nitrite (LE/N), white blood cells (WBC), all small particles (ASP), bacteria, and yeast. Positive culture grew ≥ 10(4) CFU/mL of 1 or 2 uropathogens. Method A assessed LE/N, WBCs ≥ 6/µL, and bacteria/yeast. Method B assessed WBCs ≥ 6/µL, bacteria/yeast, and ASP ≥ 10,000. Each was compared to culture results, clinician's diagnosis (CD), or expert review (ER). Sensitivities by culture were 88.7% (Method A) and 88.3% (Method B), with negative predictive values (NPVs) of 94.4% and 94.2%, respectively. Sensitivity and NPV increased for comparison to the CD (99.6%) and NPVs of 99.0% and 99.3% compared to ER. ASP did not enhance specificity, sensitivity, or NPV. The iQ200 Workstation performed well by any standard, thus providing a reliable system by which to improve the use of laboratory resources.

In vitro activity and durability of a combination of an antibiofilm and an antibiotic against vascular catheter colonization.

Catheter-associated infections can cause severe complications and even death. Effective antimicrobial modification of catheters that can prevent device colonization has the potential of preventing clinical infection. We studied in vitro the antimicrobial activities of central venous catheters impregnated with N-acetylcysteine (NAC), an antibiofilm agent, and a broad-spectrum antibiotic against a range of important clinical pathogens. NAC-levofloxacin-impregnated (NACLEV) catheters were also evaluated for their antiadherence activity. NACLEV catheters produced the most active and durable antimicrobial effect against both Gram-positive and Gram-negative isolates and significantly reduced colonization (P < 0.0001) by all tested pathogens compared to control catheters. These in vitro results suggest that this antimicrobial combination can potentially be used to combat catheter colonization and catheter-associated infection.

In vitro potency and in vivo efficacy of a novel bis-indole antimicrobial compound in reducing catheter colonization.

Vascular catheters coated with a novel antimicrobial agent (MBX1631) were studied for their ability to protect against bacterial colonization in vitro and in a rabbit model. MBX1631-coated catheters were significantly less likely to become colonized than control catheters both in vitro and in vivo (P < 0.001). Furthermore, device-associated infection was significantly lower in MBX1631-coated catheters than in uncoated ones (P < 0.005).

Impact of an assay that enables rapid determination of Staphylococcus species and their drug susceptibility on the treatment of patients with positive blood culture results.

OBJECTIVE: To determine whether an earlier determination of staphylococcal species and their antibiotic susceptibility decreases unnecessary antistaphylococcal treatment and/or facilitates earlier appropriate treatment. METHODS: We used the Xpert MRSA/SA BC system (Cepheid) for immediate determination of species and their drug susceptibility in patients whose blood cultures revealed gram-positive cocci in clusters. We compared the treatment of patients whose physicians received early notification of these results (group 1) with the treatment of patients in a historical cohort with delayed reporting after traditional microbiological studies (group 2). Outcomes were analyzed according to whether blood culture was positive for Staphylococcus species other than S. aureus, methicillin-susceptible S. aureus (MSSA), or methicillin-resistant S. aureus (MRSA) and whether the drugs used were appropriate for methicillin-susceptible or methicillin-resistant staphylococci (hereafter referred to as "MSS drug" or "MRS drug" therapy, respectively). RESULTS: There were 44 (76%) of 58 patients with bacteremia due to Staphylococcus species other than S. aureus in group 1 and 58 (55%) of 106 patients with bacteremia due to Staphylococcus species other than S. aureus in group 2 who received no antistaphylococcal antibiotics (P < .01). Five (6%) of 89 patients in group 1 and 31 (25%) of 123 patients in group 2 received 0-168 hours (0-7 days) of MRS drug therapy (P < .01). Among patients with MSSA bacteremia, the mean time to initiation of appropriate therapy was 5.2 hours in group 1 and 49.8 hours in group 2 (P = .007). Excluding patients who received MRS drug therapy for unrelated conditions, the mean duration of treatment was 19.7 hours in group 1 and 80.7 hours in group 2 (P = .003). Six (50%) of the 12 patients in group 1 and 39 (81%) of the 48 patients in group 2 received MRS drug therapy for MSSA bacteremia (P = .025). Time to initiation of therapy for MRSA bacteremia did not differ between groups. CONCLUSIONS: The use of an assay with rapid results reduced the use of antistaphylococcal therapy among patients who did not have S. aureus bacteremia; it also decreased the use of MRS drug therapy and led to earlier appropriate therapy among patients with MSSA bacteremia.

Pulmonary paragonimiasis diagnosed by fine-needle aspiration biopsy.

We report a case of paragonimiasis involving a 12-year-old Latin American boy. The diagnosis was made by fine-needle aspiration biopsy of a pulmonary nodule. Identification of the species by morphometric analysis of the eggs indicated that the infection was caused by Paragonimus mexicanus.

Sequential outbreaks of infections by distinct Acinetobacter baumannii strains in a public teaching hospital in Houston, Texas.

Invasive disease due to Acinetobacter baumannii is an increasing problem in health care settings worldwide. Whether certain clones of A. baumannii are more likely to cause invasive disease in hospitalized patients is unknown. We studied all patients at a public teaching hospital in Houston, Texas, from whom the Acinetobacter calcoaceticus-Acinetobacter baumannii complex was isolated over a 14-month period in 2005 to 2006. One hundred seven unique patient isolates were identified, with 87 of the strains classified as being A. baumannii, the majority of which were multidrug resistant. The A. baumannii isolates were comprised of 18 unique pulsed-field types, with strains of clone A and clone B accounting for 66 of the 87 isolates. Epidemiologic analysis showed the predominance of the two A. baumannii clones at distinct time periods, with the remainder of the A. baumannii and non-A. baumannii strains being evenly distributed. Patients from whom clone A strains were isolated were more likely to be bacteremic than were patients with other A. baumannii isolates. Conversely, clone B strains were more likely to be isolated from patients with tertiary peritonitis. Patients from whom clone A was isolated had a significantly higher rate of mortality. Multilocus sequence typing demonstrated that clones A and B are related to each other and to A. baumannii strains previously isolated in Western Europe, sharing five of seven alleles. Taken together, we conclude that the outbreak of the A. calcoaceticus-A. baumannii complex in our institution was due to two distinct A. baumannii clones that were associated with significantly different patient outcomes.

Oral step-down therapy is comparable to intravenous therapy for Staphylococcus aureus osteomyelitis.

BACKGROUND: We hypothesized that regimens with an early switch to oral antibiotics are as effective as prolonged parenteral regimens for staphylococcal osteomyelitis. METHODS: We retrospectively reviewed records of adult patients with osteomyelitis caused by Staphylococcus aureus as determined by sterile site cultures, who had at least 6 months of follow-up post-therapy. The population was divided into two treatment groups: (1) an intravenous group (i.v.) that received > or = 4 weeks of parenteral therapy, and (2) a switch group that received < 4 weeks of intravenous followed by oral therapy. RESULTS: A total of 72 patients (36 in each group) were identified with groups evenly matched for demographic and clinical characteristics. The overall apparent cure rate was 74%; 69% for the i.v. group and 78% for the switch group (P=0.59). Apparent cure rates were similar regardless of duration of intravenous therapy: 83% < 2 weeks, 72% 2-4 weeks, 75% 4-6 weeks and 66% > or = 6 weeks (P=0.68). Among the 39 patients who received rifampin-based combinations, those treated simultaneously with vancomycin and rifampin did significantly worse than those who received other rifampin combinations (P<0.02). Overall, MRSA infections responded poorly compared to MSSA (65% apparently cured versus 83%). However, 11/14 (79%) MRSA patients who received rifampin combinations, other than vancomycin and rifampin simultaneously, were apparently cured. CONCLUSIONS: Overall outcomes did not differ significantly between i.v. and switch groups. Given the markedly lower costs and ease of administration, prolonged oral regimens after initial intravenous therapy may be a preferred regimen for staphylococcal osteomyelitis.

Bacteraemia in the elderly: predictors of outcome in an urban teaching hospital.

OBJECTIVES: To analyze the underlying factors of mortality in elderly adults with bacteraemia. METHODS: The study included 238 episodes of bacteraemia in an urban public teaching hospital. Retrospective chart review recorded demographic information, comorbid conditions, length of stay, source of infection, and physiologic and laboratory data on admission. RESULTS: Of the 238 episodes of bacteraemia, 128 patients were 65-74 years of age and 110 patients were > or =75 years of age. Eighty-one percent came from home. Fifty-four percent had Gram positive cocci detected in blood cultures and 36% had Gram negative bacilli. Factors associated with increased odds of mortality included underlying renal disease, admission to MICU, hypotension and hypoalbuminemia. Decreased odds of mortality were associated with being admitted from home and receiving appropriate antibiotics. CONCLUSIONS: Bacteraemia in the elderly has a high mortality rate, but is not significantly increased in those >or =75 years of age. The recent microbiology has shifted from Gram negative bacilli to Gram positive cocci. Physiologic abnormalities on admission predict worse outcomes in the elderly bacteraemic patient. Hypoalbuminemia on admission is associated with higher mortality rates in the elderly.