Aerobic and anaerobic microbiology of paronychia

Pus specimens from 28 patients with paronychia of the finger yielded bacterial growth by techniques for cultivation of aerobic and anaerobic bacteria. Anaerobic and aerobic organisms only were isolated in pure culture in five (18%) and eight patients (29%), respectively; mixed aerobic and anaerobic flora were present in 15 patients (54%). Seventy-two isolates were recovered, or 2.6 isolates per specimen. The predominant anaerobic organisms were Gram-positive anaerobic cocci, Bacteroides species, and Fusobacterium species. The predominant aerobic organisms were Staphylococcus aureus, gamma-hemolytic streptococci, Eikenella corrodens, group A beta-hemolytic streptococci, alpha-hemolytic streptococci, and Klebsiella pneumoniae. Candida albicans was recovered in four cases. This study demonstrates the mixed aerobic and anaerobic bacteriology of paronychia.     

Asporogenic anaerobic empyema--clinical and bacteriological investigations of 31 patients with anaerobic empyema

The author reviewed the records of 31 patients with asporogenic anaerobic empyema mostly seen in the wards of Internal Medicine, Juntendo University Hospital during the 27 years between 1961 and 1988, and obtained the following results. 1. There were 25 males and 8 females with an average age of 57.8 and 51.0 y/o (range, 25 to 79 y/o), respectively males more than forty years old occupied 74.2 percent of all cases. 28 patients (90%) had underlying conditions. 2. The cases of mixed infections with anaerobes and aerobes were only 22.6%. 3. The isolated bacteria were microaerophilic streptococcus, Bacteroides spp., Peptostreptococcus spp., Fusobacterium spp. etc. in this order. 4. There were no relationships between anaerobic infections with or without aerobes and putrid odor of pleural effusion. 5. Bacteroides spp. were isolated most in the group with putrid pleural effusion, however, they were not isolated in the group without putrid pleural effusion at all. This fact suggests that there is an intimate relationship between putrid odor and Bacteroides spp. 6. There was no deceased case which pleural effusion had been drained sufficiently with open or closed drainage. It suggests that sufficient drainage is the most important in therapeutic procedures of asporogenic anaerobic empyema.     

Pericarditis due to anaerobic bacteria

This review describes the microbiology, diagnosis and management of pericarditis due to anaerobic bacteria. The predominant anaerobes recovered from patients with pericarditis were: gram-negative bacilli (mostly of the Bacteroides fragilis group), anaerobic streptococci, Clostridium spp., Fusobacterium spp., and Bifidobacterium spp. Anaerobic bacteria can be isolated in pericarditis resulting from the following mechanisms: (1) spread from a contiguous focus of infection, either de novo or after surgery or trauma (pleuropulmonary, esophageal fistula or perforation, and odontogenic); (2) spread from a focus of infection within the heart, most commonly from endocarditis; (3) hematogenous infection, and (4) direct inoculation as a result of a penetrating injury or cardiothoracic surgery. No differences were found in the clinical diagnostic features between cases of pericarditis due to anaerobic bacteria and those due to aerobic and facultative bacteria. Anaerobic gram-negative bacilli have increased their resistance to penicillins and other antimicrobials in the last decade. Complete identification and testing for antimicrobial susceptibility and lactamase production are therefore essential for the management of infections caused by these bacteria. Treatment of pericarditis involving anaerobic bacteria includes the use of antibiotic therapy effective against these organisms.     

Chronic sinusitis in children and adults: Role of bacteria and antimicrobial management

The nasopharynx serves as the reservoir for anaerobic bacteria as well as pathogenic bacteria that can cause respiratory infections including sinusitis. Some of these organisms possess the ability to interfere with the growth of potential pathogens and may play a role in preventing infections. Anaerobic bacteria emerge as pathogens as the infection becomes chronic. This may result from the selective pressure of antimicrobial agents that enable resistant anaerobic organisms to survive, and from the development of conditions appropriate for anaerobic growth, which include the reduction in oxygen tension and an increase in acidity within the sinus. Anaerobes were identified in chronic sinusitis in adults and children whenever techniques for their cultivation were employed. The predominant isolates were pigmented Prevotella, Fusobacterium, and Peptostreptococcus spp. The choice of antimicrobial agent in chronic sinusitis should provide coverage for the usual pathogens in acute sinusitis as well as beta-lactamase-producing aerobic and anaerobic organisms.     

Gastric microflora in patients receiving H2-blocker

The gastric microflora of 21 cases receiving histamine H2-receptor antagonists (H2-blocker) were studied. Patients not given H2-blocker were also examined for gastric microflora. The gastric pH of patients who were receiving H2-blocker ranged from 1.91 to 6.51 (mean, 4.32). The gastric pH of over 5.00 was seen in 10 cases. Aerobic bacteria were isolated from 20 cases (95%). Aerobic bacterial counts per ml of gastric aspirates correlated positively with the pH of those aspirates but was little correlation between the pH of the gastric aspirates and the number of anaerobic bacteria of the samples, which were positive in 7 cases (33%). Candida and Staphylococcus were predominant isolates with positive rates of 82% and 41%, respectively. While Fusobacterium was isolated from 33% of the samples, none of the Bacteroides fragilis group organisms were isolated. It was also observed in the control group that aerobic and anaerobic bacteria were isolated from the gastric aspirates with high pH. These results suggest that in patients receiving H2-blocker anaerobes as well as aerobes may have the possibility to become pathogen for aspirate pneumonia and so on because of the overgrowth of anaerobic bacteria in the gastric fluid.     

Bacteriology and beta-lactamase activity in acute exacerbation of chronic bronchitis.

OBJECTIVES: To assess the bacteriology of beta-lactamase (BL) enzyme activity in sputum of 40 patients with acute exacerbation of chronic bronchitis (AECB). METHODS: The microbiology, BL production by the different isolates, and BL contents in the sputum were determined. RESULTS: Eighty-four isolates were recovered (2.1 isolates per specimen), 44 aerobic and facultative (1.1 isolates per specimen), and 40 anaerobic (1.0 isolate per specimen). Aerobic bacteria were recovered in only 9 (22.5%) specimens, anaerobic bacteria in 9 (22.5%), and mixed aerobic and anaerobic bacteria were found in 22 (55%). The predominant aerobic isolates were Streptococcus pneumoniae (15 isolates), Haemophilus influenzae (11), Moraxella catarrhalis and Klebsiella pneumoniae (4 each). The predominant anaerobes were Peptostreptococcus sp. (19), Prevotella sp. (11), and Fusobacterium sp.(6). Mixed flora were present in 25 (62.5%) specimens, and the number of isolates varied from 2 to 5 per specimen. Thirty-nine beta-lactamase-producing bacteria (BLPB) were isolated in 33 (82.5%) of the 40 cases. The predominant aerobic BLPB were H. influenzae, M. catarrhalis, K. pneumoniae, Staphylococcus aureus, and Escherichia coli. The predominant anaerobic BLPB were Prevotella sp. and Fusobacterium sp. Beta-lactamase activity was detected in 26 (79%) of 33 of specimens in which BLPB were isolated, and in none of the seven specimens that did not harbor BLPB. CONCLUSIONS: The rapid detection of BL activity in sputum specimens may have implications for the antimicrobial management with AECB.     

Endocarditis due to anaerobic bacteria

This review describes the microbiology, diagnosis and management of endocarditis due to anaerobic bacteria. Anaerobic bacteria are an uncommon but important cause of endocarditis. Most cases of anaerobic endocarditis are caused by anaerobic cocci, Propionibacterium acnes and Bacteroides fragilis group. Predisposing factors and signs and symptoms of endocarditis caused by anaerobic bacteria are similar to those seen in endocarditis with facultative anaerobic bacteria with the following exceptions: the gastrointestinal tract was the most common source for B. fragilis group endocarditis, the head and neck were the most common origin for Fusobacterium and Bacteroides spp., and the head and neck and genitourinary tract were the most common source for peptostreptococci. Complications with anaerobic endocarditis include valvular destruction, multiple mycotic aneurysms, aortic-ring abscess, aortitis, cardiogenic shock, dysrhythmias and septic shock. The mortality rate for patients with anaerobes endocarditis is 21-43%. Treatment of endocarditis involving anaerobic bacteria includes the use of antibiotic therapy effective against these organisms.     

Bacterial colonization, tracheobronchitis, and pneumonia following tracheostomy and long-term intubation in pediatric patients.

Serial tracheal cultures for aerobic and anaerobic bacteria were obtained from 27 pediatric patients during one year of follow-up. The patients had required tracheostomy and prolonged intubation for periods ranging from 3 to 12 months (average, 7 1/2 months). Cultures of tracheal aspirates yielded 1,508 isolates of pathogenic aerobic (969 isolates) and anaerobic (539 isolates) bacteria. The most frequent aerobic isolates were Streptococcus pneumoniae and Staphylococcus aureus. The predominant anaerobes were anaerobic gram-positive cocci, Fusobacterium nucleatum, and Bacteroides fragilis. Replacement of one pathogen by another occurred frequently. Tracheobronchitis occurred in 24 patients, all of whom had episodes of pneumonia. The data suggest that anaerobic bacteria are a part of the bacterial flora in colonization, tracheobronchitis, and pneumonia in patients with tracheostomy and prolonged intubation.     

Bacteriology of bronchial secretions in non-tubercular lower respiratory tract infections

Fifty samples of bronchial secretions collected from patients of non-tubercular lower respiratory tract infections through fiberoptic bronchoscopy (FOB) were cultured both for aerobic and anaerobic organisms. Thirty-three (66%) samples yielded bacteria. Out of these, thirty were isolated in pure culture and from three, a mixed growth of aerobic and anaerobic micro-organisms was obtained. Aerobic bacteria were the predominant isolates. Stephylococcus aureus (10), pseudomonas (9) and streptococcus pneumoniae (8) were the major aerobic isolates. Ciprofloxacin was found to be the most effective drug against aerobes and metronidazole against anaerobes in vitro susceptibility tests.     

The bacteriology of aspiration pneumonia

A prospective study of 54 cases of pulmonary infection following aspiration was performed. Specimens utilized for bacteriologic study were either transtracheal aspirates, empyema fluid or blood. Appropriate anaerobic bacteriologie methods were employed. Anaerobic bacteria were recovered in 50 patients (93 per cent) and were the only pathogens in 25 (46 per cent). The predominant species were Bacteroides melanino-genicus, Fusobacterium nucleatum and anaerobic or microaerophilic gram-positive cocci. Bacteroides fragilis, which is resistant to many commonly used antibiotics, was recovered in nine patients (17 per cent). Aerobic and facultative bacteria were present in 29 patients (54 per cent), but anaerobes were present concurrently in all but 4. Enteric gram-negative bacilli and pseudomonads were particularly common in patients whose disease developed in the hospital. Eleven patients with mixed aerobic and anaerobic infections were treated successfully with antibiotics which were active only against the anaerobic isolates, thereby further implicating the pathogenic role of these microorganisms. The results indicate that anaerobes play a key role in most cases of infection following aspiration.     

Microbiology of severe aspiration pneumonia in institutionalized elderly

We sought to investigate prospectively the microbial etiology and prognostic indicators of 95 institutionalized elders with severe aspiration pneumonia, and to investigate its relation to oral hygiene in using quantitative bronchial sampling. Data collection included demographic information, Activity of Daily Living, Plaque Index, antimicrobial therapy, and outcome. Out of the 67 pathogens identified, Gram-negative enteric bacilli were the predominant organisms isolated (49%), followed by anaerobic bacteria (16%), and Staphylococcus aureus (12%). The most commonly encountered anaerobes were Prevotella and Fusobacterium species. Aerobic Gram-negative bacilli were recovered in conjunction with 55% of anaerobic isolates. The Plaque Index did not differ significantly between the aerobic (2.2 +/- 0.4) and the anaerobic group (2.3 +/- 0.3). Functional status was the only determinant of the presence of anaerobic bacteria. Although seven cases with anaerobic isolates received initially inadequate antimicrobial therapy, six had effective clinical response. The crude mortality was 33% for the aerobic and 36% for the anaerobic group (p = 0.9). Stepwise multivariate analysis identified hypoalbuminemia (p < 0.001) and the burden of comorbid diseases (p < 0.001) as independent risk factors of poor outcome. In view of the rising resistance to antimicrobial agents, the importance of adding anaerobic coverage for aspiration pneumonia in institutionalized elders needs to be reexamined.     

Clinical spectrum of bacteroidaceae in a tertiary care hospital

Members of Bacteroidaceae family are the most commonly isolated anaerobic pathogens in humans. This study summarises our experience of isolation and antimicrobial susceptibility pattern of these anaerobes from diverse clinical infections in a tertiary care hospital. Over a period of 5 years, 611 samples were received for anaerobic culture. Of these, 53 specimens yielded 62 anaerobic isolates. Thirty of the 62 isolates (48.4%) belonged to Bacteroidacea family obtained from 29 patients. They comprised of 14 (14/32; 43.7%) Prevotella spp., 13 (13/32; 40.6%) Bacteroides spp., 3 (3/32; 9.3%) Porphyromonas spp and Fusobacterium (2/32; 6.2%). In 14 of 27 patients (48%) the infection was polymicrobial. All the isolated strains were sensitive to metronidazole. This study highlights need for adopting anaerobic culture technique as a routine diagnostic procedure and constant monitoring of antimicrobial susceptibility of all anaerobic isolates.     

Characteristics of brain abscess with isolation of anaerobic bacteria

In view of its localization, brain abscess (BA) usually requires medical and surgical care. A broad spectrum of bacteria is involved. Recent reports stress the increasing frequency of anaerobes, but their impact has not been well evaluated. A retrospective review was conducted of all episodes of documented BA admitted in a tertiary-care hospital over a 10 y period. BA due to anaerobic bacteria (group A) were compared with other cases (group B) to determine the frequency and eventual characteristics of BA with isolated anaerobic bacteria. Between 1991 and 2000, BA were diagnosed in 42 patients (28M, 14F, mean age 54.6 y). No differences in clinical features and laboratory findings were found between patients with BA caused by anaerobic (n = 22) and only aerobic (n = 20) bacteria. Using appropriate microbiological techniques, 41 anaerobic bacteria strains were isolated in 22 of 42 patients (52.4%) with BA. Anaerobic bacteria were associated with aerobic strains in 5 patients (12%), whereas in 17 patients (40.5%) only anaerobic strains were isolated in cerebral puncture cultures. The most frequently isolated species were Fusobacterium nucleatum (n = 14), Prevotella sp. (n = 8), Actinomyces sp. (n = 6) and Bacteroides sp. (n = 4). Compared with group B, group A had more cases of a single abscess (p = 0.03) and ear, nose and throat (ENT) as a source of infection (p = 0.04), and seemed to have a better outcome (p = 0.07). These results emphasize the important role that anaerobic bacteria play in BA. The presence of such pathogens must be evoked when faced with a single abscess, an ENT infection, or both. Therapy should take into account this high frequency.     

Role of anaerobic bacteria in spontaneous peritonitis of cirrhosis: report of two cases and review of the literature.

The role of anaerobic or microaerophillic bacteria in spontaneous peritonitis of cirrhosis has not been clearly defined. Among 126 cases recorded in the literature, in only eight (6 per cent), including the two reported here, was bacterascites associated with anaerobic or microaerophilic bacteria. Clinical features in these cases were indistinguishable from those associated with aerobic bacteria. However, polymicrobial bacterascites occurred in four of eight cases associated with anaerobes, as contrasted with only 10 of 118 cases (8 per cent) associated with aerobes alone. On the other hand, concurrent bacteremia occurred in only one of eight cases associated with anaerobes as contrasted with 52 of 118 cases (44 per cent) of aerobic spontaneous peritonitis. Experimental evidence is cited in an attempt to explain this relatively low incidence of spontaneous peritonitis associated with anaerobic or microaerophilic bacteria, despite the high density of these organisms in the normal bowel flora.     

Linezolid in the treatment of brain abscess due to Peptostreptococcus

Brain abscesses can be caused by bacteria, fungi, and parasites. Among bacteria, anaerobic organisms include the Bacteroides species group, Fusobacterium, Peptostreptococcus, and Propionibacterium. In these cases, a 4-week course of parenteral penicillin/cefalosporin and metronidazole is the standard of treatment. We describe a case of brain abscess secondary to anaerobic infection with Peptostreptococcus, which was successfully treated with parenteral and oral linezolid after failure of standard therapy.     

Susceptibility of the liver and biliary tract to anaerobic infection in extrahepatic biliary tract obstruction. Bacteriological investigations - an experimental study in rabbits.

The influence of common duct occlusion on susceptibility to infection with anaerobic gram-negative rods was investigated in rabbits. Intravenous inoculation was performed with three B. fragilis strains isolated from human infections and with a stock culture of Fusobacterium mortiferum. Liver tissue, gallbladder, bile, and blood were investigated. Anaerobic culture procedures were based on the use of a 'glove-box' with an oxygen-free atmosphere and pre-reduced, anaerobically sterilized media. Anaerobic transport was based on flushing of samples with oxygen-free carbon dioxide and transport-time less than 30 minutes. In regard to two B. fragilis strains (ss. fragilis) and in regard to Fusobacterium mortiferum, common duct occlusion significantly increased the number of infected animals compared to a control group of inoculated animals without common duct occlusion. Spontaneous infection did not arise in a control group of animals with common duct ligation. It is concluded that: 1) in biliary tract occlusion, anaerobic bacteria are able to invade the biliary tract from the blood stream, and 2) biliary tract occlusion produces sufficient anaerobic conditions for obligate anaerobic bacteria to multiply in the bile.     

Aerobic and anaerobic microbiology of external otitis.

Microbiological and clinical data from 46 patients with external otitis were retrospectively evaluated. Specimens were processed for isolation of aerobic and anaerobic bacteria. A total of 42 aerobic bacteria, 22 anaerobic bacteria, and 3 Candida albicans organisms were recovered. Aerobic bacteria only were isolated from 31 patients (67%), anaerobic bacteria only were isolated from 8 (17%), and mixed aerobic and anaerobic bacteria were isolated from 4 (9%). C. albicans alone was recovered from two patients (4%), and the organism was mixed with aerobic bacteria in one case (2%). The most common isolates were Pseudomonas aeruginosa (19 instances), Peptostreptococcus species (11), Staphylococcus aureus (7), and Bacteroides species (5). One isolate was recovered from 30 patients (65%), 2 isolates were recovered from 11 (24%), and 3 isolates were recovered from 5 (11%). beta-Lactamase activity was detected in 32 isolates recovered from 27 specimens (59%). These data illustrate the polymicrobial nature of external otitis in one-third of the patients and the role of anaerobic bacteria in one-quarter of them. Further prospective studies are warranted for evaluating the role of anaerobic bacteria in this infection and the therapeutic implications of these findings.     

The bacteriology of pleural infection by genetic and standard methods and its mortality significance

BACKGROUND: Antibiotic choices for pleural infection are uncertain as its bacteriology is poorly described. METHODS: Pleural fluid from 434 pleural infections underwent standard culture and a screen for bacteria by amplification and sequencing of bacterial 16S ribosomal RNA gene. RESULTS: Approximately 50% of community-acquired infections were streptococcal, and 20% included anaerobic bacteria. Approximately 60% of hospital-acquired infections included bacteria frequently resistant to antibiotics (methicillin-resistant Staphylococcus aureus, 25%; Enterobacteriaceae, 18%; Pseudomonas spp., 5%, enterococci, 12%). Mortality was increased in hospital-acquired infection (hospital, 17/36 [47%]; community, 53/304 [17%]; relative risk, 4.24; 95% confidence interval, 2.07-8.69; p < 0.00001; chi(2), 1 df = 17.47) and in gram-negative (10/22 [45%]), S. aureus (15/34 [44%]), or mixed aerobic infections (13/28 [46%]), compared with streptococcal infection (23/137 [17%]) and infection including anaerobic bacteria (10/49 [20%]; p < 0.00001, chi(2), 4 df = 23.35). CONCLUSION: Pleural infection differs bacteriologically from pneumonia and requires different treatment. Antibiotics for community-acquired infection should treat aerobic and anaerobic bacteria. Hospital-acquired, gram-negative S. aureus and mixed aerobic infections have a high mortality rate.     

Microflora in the trophic ulcers of the foot in leprosy

Out of 25 cases of trophic ulcers of the foot, 10 (40%) were both aerobic and anaerobic, 14 (56%) only aerobic and one (4%) showed no growth of bacteria. With the exception of two cases (8%) in the aerobic group, all others showed mixed infections. A wide range of bacteria is reported. Topical application of gentamicin and chloramphenicol is recommended, based on the results of in vitro sensitivity.     

Outpatient management of uncomplicated lower-extremity infections in diabetic patients

Most diabetic foot infections are believed to be caused by both aerobic and anaerobic bacteria and to require hospitalization and parenteral antimicrobial therapy. We prospectively evaluated diabetic patients with non-limb-threatening lower-extremity infections not yet treated with antibiotics. The patients were randomized to outpatient treatment with oral clindamycin hydrochloride or cephalexin for 2 weeks and evaluated every 3 to 7 days. In 56 assessable patients, curettage yielded a mean of 2.1 microorganisms. Aerobic gram-positive cocci were isolated in 50 cases (89%), and were the sole pathogen in 21 (42%) of these. Aerobic gram-negative bacilli and anaerobes were isolated in 20 (36%) and 7 (13%) cases, respectively, and almost always in polymicrobial infections. Fifty-one infections (91%) were eradicated, 42 (75%) after 2 weeks of treatment; only 5 (9%) were initially treatment failures, and 3 (5%) were subsequently cured with further outpatient oral antibiotic treatment. After a mean follow-up of 15 months, no further treatment was required in 43 (84%) of the cured patients. Previously untreated lower-extremity infections in diabetic patients are usually caused by aerobic gram-positive cocci, and generally respond well to outpatient management with oral antibiotic therapy.