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Abstract
Alteration in the host microbiome at skin and mucosal surfaces plays a role in the function of the immune system, and may predispose immunocompromised patients to infection. Because obligate anaerobes are the predominant type of bacteria present in humans at skin and mucosal surfaces, immunocompromised patients are at increased risk for serious invasive infection due to anaerobes. Laboratory approaches to the diagnosis of anaerobe infections that occur due to pyogenic, polymicrobial, or toxin-producing organisms are described. The clinical interpretation and limitations of anaerobe recovery from specimens, anaerobe-identification procedures, and antibiotic-susceptibility testing are outlined. Bacteriotherapy following analysis of disruption of the host microbiome has been effective for treatment of refractory or recurrent Clostridium difficile infection, and may become feasible for other conditions in the future.
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Affiliation(s)
- Deirdre L Church
- Departments of Pathology & Laboratory Medicine and Medicine, University of Calgary, and Division of Microbiology, Calgary Laboratory Services, Calgary, Alberta, Canada T2N 1N4
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Are incidence and epidemiology of anaerobic bacteremia really changing? Eur J Clin Microbiol Infect Dis 2015; 34:1621-9. [PMID: 26017663 DOI: 10.1007/s10096-015-2397-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/29/2015] [Indexed: 10/23/2022]
Abstract
Incidence, prognosis and need of performing blood cultures for anaerobic bacteria are under debate, mainly due to the belief that the presence of anaerobes in blood can be easily suspected on clinical basis. We aimed to assess these three points in a retrospective analysis of a 10-year experience in our tertiary hospital. All episodes of significant anaerobic bacteremia diagnosed from 2003 to 2012 were included. Risk factors for mortality and clinical predictability of anaerobic bacteremia were evaluated in 113 randomly selected episodes. Overall incidence of anaerobic bacteremia was 1.2 episodes/1000 admissions, with no significant changes during the 10-year study period. B. fragilis group (38.1 %) and Clostridium spp. (13.7 %) were the most frequent isolated microorganisms. As for the clinical study, 43.4 % of the patients had a comorbidity classified as ultimately fatal or rapidly fatal according to the McCabe and Jackson scale. Clinical manifestations suggestive of anaerobic involvement were present in only 55 % of the patients. Twenty-eight patients (24.8 %) died during the hospitalization. Independent predictive factors of mortality were a high Charlson's comorbidity index and presentation with septic shock, whereas, an adequate source control of the infection was associated with a better outcome. In our centre, incidence of anaerobic bacteremia remained stable during the last decade. The routine use of anaerobic BCs seems to be adequate, since in about half of the cases anaerobes could not be suspected on clinical bases. Moreover, prompt source control of infection is essential in order to reduce mortality of patients with anaerobic bacteremia.
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Hamadah AM, Elrashidi MY, McDonald FS. 65-year-old woman with confusion. Mayo Clin Proc 2013; 88:e1-5. [PMID: 23274028 DOI: 10.1016/j.mayocp.2012.07.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 07/01/2012] [Accepted: 07/13/2012] [Indexed: 11/29/2022]
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Paul M, Shani V, Muchtar E, Kariv G, Robenshtok E, Leibovici L. Systematic review and meta-analysis of the efficacy of appropriate empiric antibiotic therapy for sepsis. Antimicrob Agents Chemother 2010; 54:4851-63. [PMID: 20733044 PMCID: PMC2976147 DOI: 10.1128/aac.00627-10] [Citation(s) in RCA: 476] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 07/06/2010] [Accepted: 08/14/2010] [Indexed: 11/20/2022] Open
Abstract
Quantifying the benefit of early antibiotic treatment is crucial for decision making and can be assessed only in observational studies. We performed a systematic review of prospective studies reporting the effect of appropriate empirical antibiotic treatment on all-cause mortality among adult inpatients with sepsis. Two reviewers independently extracted data. Risk of bias was assessed using the Newcastle-Ottawa score. We calculated unadjusted odds ratios (ORs) with 95% confidence intervals for each study and extracted adjusted ORs, with variance, methods, and covariates being used for adjustment. ORs were pooled using random-effects meta-analysis. We examined the effects of methodological and clinical confounders on results through subgroup analysis or mixed-effect meta-regression. Seventy studies were included, of which 48 provided an adjusted OR for inappropriate empirical antibiotic treatment. Inappropriate empirical antibiotic treatment was associated with significantly higher mortality in the unadjusted and adjusted comparisons, with considerable heterogeneity occurring in both analyses (I(2) > 70%). Study design, time of mortality assessment, the reporting methods of the multivariable models, and the covariates used for adjustment were significantly associated with effect size. Septic shock was the only clinical variable significantly affecting results (it was associated with higher ORs). Studies adjusting for background conditions and sepsis severity reported a pooled adjusted OR of 1.60 (95% confidence interval = 1.37 to 1.86; 26 studies; number needed to treat to prevent one fatal outcome, 10 patients [95% confidence interval = 8 to 15]; I(2) = 46.3%) given 34% mortality with inappropriate empirical treatment. Appropriate empirical antibiotic treatment is associated with a significant reduction in all-cause mortality. However, the methods used in the observational studies significantly affect the effect size reported. Methods of observational studies assessing the effects of antibiotic treatment should be improved and standardized.
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Affiliation(s)
- Mical Paul
- Unit of Infectious Diseases, Rabin Medical Center, Beilinson Hospital, Petach Tikva, Israel.
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Bishara J, Wattad M, Leibovici L, Samra Z, Lev B, Abramson E, Paul M. Predictors for anaerobic bacteraemia beyond the source of infection: Retrospective, nested, case-control study. ACTA ACUST UNITED AC 2009; 41:33-6. [DOI: 10.1080/00365540802510168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Park Y, Lee Y, Kim M, Choi JY, Yong D, Jeong SH, Kim JM, Lee K, Chong Y. Recent Trends of Anaerobic Bacteria Isolated from Clinical Specimens and Clinical Characteristics of Anaerobic Bacteremia. Infect Chemother 2009. [DOI: 10.3947/ic.2009.41.4.216] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Yongjung Park
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
| | - Yangsoon Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
| | - Myungsook Kim
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
| | - Jun Yong Choi
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Dongeun Yong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
| | - Seok Hoon Jeong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
| | - June Myung Kim
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Korea
| | - Kyungwon Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
| | - Yunsop Chong
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, College of Medicine, Yonsei University, Seoul, Korea
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Wilson M. Medical Microbiology: Assuring the Quality of Clinical Microbiology Test Results. Clin Infect Dis 2008; 47:1077-82. [DOI: 10.1086/592071] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Wilson JR, Limaye AP. Risk factors for mortality in patients with anaerobic bacteremia. Eur J Clin Microbiol Infect Dis 2004; 23:310-6. [PMID: 15024626 DOI: 10.1007/s10096-004-1111-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Risk factors for mortality in anaerobic bacteremia have been incompletely defined. The aims of the present study were to determine clinical significance by pathogen for a broad range of obligate anaerobic organisms isolated from blood, and to define the factors independently associated with mortality among those with clinically significant bacteremia. All patients who had anaerobic bacteria isolated from blood over a 19-month period (from 1 September 1998 to 1 April 2000) at two urban teaching hospitals were included in this study. Each case was analyzed for clinical significance by means of a retrospective medical record review using predetermined definitions. Information was collected on a broad range of clinical and microbiological factors, which were evaluated for their association with mortality using a Cox proportional hazards model. Among 166 patients with obligate anaerobic bacteria isolated from blood, 73 (44%) were deemed to have clinically significant bacteremia. Clinical significance ranged from 0% (0/53) for Propionibacterium spp. to 96% (43/45) for Bacteroides spp. The crude mortality rate in patients with clinically significant anaerobic bacteremia was 25% (18/73). Mortality was significantly associated with age, polymicrobial infection, and underlying heart, kidney or liver disease in univariate analysis. Only the presence of liver disease (relative risk, 5.3; 95% confidence interval, 1.7-16.0; P=0.003) and patient age (relative risk, 1.06/y; 95% confidence interval, 1.0-1.1; P=0.005) remained significant in multivariate analysis. Among patients with anaerobic bacteremia, clinical significance varies markedly by pathogen and mortality is independently associated with age and underlying liver disease.
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Affiliation(s)
- J R Wilson
- Departments of Laboratory Medicine and Medicine, University of Washington Medical Center, 1959 Northeast Pacific Street, Box 357110, Seattle, WA 98195-7110, USA
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Diekema DJ, Beekmann SE, Chapin KC, Morel KA, Munson E, Doern GV. Epidemiology and outcome of nosocomial and community-onset bloodstream infection. J Clin Microbiol 2003; 41:3655-60. [PMID: 12904371 PMCID: PMC179863 DOI: 10.1128/jcm.41.8.3655-3660.2003] [Citation(s) in RCA: 206] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2002] [Revised: 05/01/2003] [Accepted: 06/04/2003] [Indexed: 11/20/2022] Open
Abstract
We performed a prospective study of bloodstream infection to determine factors independently associated with mortality. Between February 1999 and July 2000, 929 consecutive episodes of bloodstream infection at two tertiary care centers were studied. An ICD-9-based Charlson Index was used to adjust for underlying illness. Crude mortality was 24% (14% for community-onset versus 34% for nosocomial bloodstream infections). Mortality attributed to the bloodstream infection was 17% overall (10% for community-onset versus 23% for nosocomial bloodstream infections). Multivariate logistic regression revealed the independent associations with in-hospital mortality to be as follows: nosocomial acquisition (odds ratio [OR] 2.6, P < 0.0001), hypotension (OR 2.6, P < 0.0001), absence of a febrile response (P = 0.003), tachypnea (OR 1.9, P = 0.001), leukopenia or leukocytosis (total white blood cell count of <4500 or >20000, P = 0.003), presence of a central venous catheter (OR 2.0, P = 0.0002), and presence of anaerobic organism (OR 2.5, P = 0.04). Even after adjustments were made for underlying illness and length of stay, nosocomial status of bloodstream infection was strongly associated with increased total hospital charges (P < 0.0001). Although accounting for about half of all bloodstream infections, nosocomial bloodstream infections account for most of the mortality and costs associated with bloodstream infection.
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Affiliation(s)
- D J Diekema
- Department of Internal Medicine, Roy J and Lucille A Carver University of Iowa College of Medicine, Iowa City, Iowa, 52242, USA
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Créixems MR, Fron C, Muñoz P, Sánchez C, Peláez T, Bouza E. Use of anaerobically incubated media to increase yield of positive blood cultures in children. Pediatr Infect Dis J 2002; 21:443-6. [PMID: 12150188 DOI: 10.1097/00006454-200205000-00025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
During a 3-year period we received 10024 blood samples for culture from pediatric patients. Overall 181 episodes of significant bacteremia were documented. During the study period we would have missed 35 (19%) of all significant episodes of pediatric bloodstream infections if we had not been using the anaerobically incubated blood bottle. Anaerobically incubated blood samples are also necessary in the pediatric population.
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Affiliation(s)
- Marta Rodríguez Créixems
- Servicio de Microbiología Clínica y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Madrid, Spain
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Wilson ML, Mirrett S, Meredith FT, Weinstein MP, Scotto V, Reller LB. Controlled clinical comparison of BACTEC plus anaerobic/F to standard anaerobic/F as the anaerobic companion bottle to plus aerobic/F medium for culturing blood from adults. J Clin Microbiol 2001; 39:983-9. [PMID: 11230415 PMCID: PMC87861 DOI: 10.1128/jcm.39.3.983-989.2001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To determine the optimal anaerobic companion bottle to pair with BACTEC Plus Aerobic/F medium for recovery of pathogenic microorganisms from adult patients with bacteremia and fungemia, we compared Plus Anaerobic/F bottles with Standard Anaerobic/F bottles, each of which was filled with 4 to 6 ml of blood. The two bottles were paired with a Plus Aerobic/F bottle filled with 8 to 12 ml of blood. A total of 14,011 blood culture sets were obtained. Of these, 11,583 sets were received with all three bottles filled adequately and 12,257 were received with both anaerobic bottles filled adequately. Of 818 clinically important isolates detected in one or both adequately filled anaerobic bottles, significantly more staphylococci (P < 0.001), streptococci (P < 0.005), Escherichia coli isolates (P < 0.02), Klebsiella pneumoniae isolates (P < 0.005), and all microorganisms combined (P < 0.001) were detected in Plus Anaerobic/F bottles. In contrast, significantly more anaerobic gram-negative bacilli were detected in Standard Anaerobic/F bottles (P < 0.05). Of 397 unimicrobial episodes of septicemia, 354 were detected with both pairs, 30 were detected with Plus Aerobic/F-Plus Anaerobic/F pairs only, and 13 were detected with Plus Aerobic/F-Standard Anaerobic/F pairs only (P < 0.05). Significantly more episodes of bacteremia caused by members of the family Enterobacteriaceae (P < 0.05) and aerobic and facultative gram-positive bacteria (P < 0.025) were detected with Plus Anaerobic/F bottles only. In a paired-bottle analysis, 810 of 950 isolates were recovered from both pairs, 90 were recovered from Plus Aerobic/F-Plus Anaerobic/F pairs only, and 50 were recovered from Plus Aerobic/F-Standard Anaerobic/F pairs only (P < 0.001). Paired Plus Aerobic/F-Plus Anaerobic/F bottles yielded significantly more staphylococci (P < 0.001), streptococci (P < 0.05), and members of the family Enterobacteriaceae (P <0.001). We conclude that Plus Anaerobic/F bottles detect more microorganisms and episodes of bacteremia and fungemia than Standard Anaerobic/F bottles as companion bottles to Plus Aerobic/F bottles in the BACTEC 9240 blood culture system.
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Affiliation(s)
- M L Wilson
- Department of Pathology and Laboratory Services, Denver Health Medical Center, Denver, Colorado 80204, USA.
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Gómez J, Esquinas A, Agudo MD, Sánchez Nieto JM, Núñez ML, Baños V, Canteras M, Valdes M. Retrospective analysis of risk factors and prognosis in non-ventilated patients with nosocomial pneumonia. Eur J Clin Microbiol Infect Dis 1995; 14:176-81. [PMID: 7614956 DOI: 10.1007/bf02310352] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Although nosocomial pneumonia in non-ventilated patients continues to be frequent and have high mortality rates, knowledge of the associated risk and prognostic factors is still limited. This retrospective study was designed to analyze epidemiological characteristics, risk and prognostic factors in patients with nosocomial pneumonia admitted to a hospital internal medicine department. Data on epidemiological, clinical and microbiological factors as well as diagnosis and clinical course were obtained from the medical records of 104 patients diagnosed with nosocomial pneumonia, according to Centers for Disease Control criteria, and from 104 control subjects. The incidence of nosocomial pneumonia was 18.8 per 1000 admissions. Risk factors significantly associated with contracting the disease were female sex, hospital stay longer than 14 days, other admission in the previous month and use of antibiotics during the previous six weeks. The most frequent underlying diseases were cardiorespiratory in nature (59.4%). Prognostic factors significantly associated with increased mortality were serious underlying disease, initially critical clinical status, severe and moderate respiratory insufficiency and bilateral radiological signs. More epidemiological data are needed to improve the diagnosis, treatment and prevention of nosocomial pneumonia.
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Affiliation(s)
- J Gómez
- Internal Medicine Service, Virgen de Arrixaca University Hospital, Murcia, Spain
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