Chronic rhinosinusitis (CRS) significantly lowers the quality of life of patients. The common use of broad spectrum antibiotics for its treatment may alter the pathogens that promote the persistence of this condition. However, the data concerning the distribution of bacteria species. in patients with CRS are not consistent.

Acute appendicitis is a common cause of acute abdomen requiring an emergency appendicectomy. Complications such as perforation and peritoneal contamination leading to peritonitis can result from delay in presentation and an emergency operation. This study prospectively recruited 101 patients diagnosed with acute appendicitis to correlate the bacterial flora with the severity of appendicitis. The results show that 90 patients had acutely inflamed or gangrenous appendicitis and 11 had perforated appendicitis. The ages ranged from 6 to 49 years with a median of 20 years. There were 59 females and 42 males. The commonest isolates were aerobic bacteria such as Escherichia coli, Group D streptococci and Klebsiella pneumoniae. Mixed infection with anaerobes such as Bacteroides fragilis was seen only in perforated appendicitis. The best choices of antibiotic were a fluoroquinolone, cephalosporin and aminoglycoside for aerobic organisms and metronidazole for anaerobes.

Anaerobic bacteria commonly cause infection in children. Anaerobes are the most predominant components of the normal human skin and mucous membranes bacterial flora and are therefore a common cause of bacterial infections of endogenous origin. Because of their fastidious nature, they are difficult to isolate from infectious sites and are often overlooked. Anaerobic infections can occur in all body sites, including the central nervous system, oral cavity, head and neck, chest, abdomen, pelvis, skin, and soft tissues. They colonize the newborn after delivery and have been recovered from several types of neonatal infections. These include cellulitis of the site of fetal monitoring, neonatal aspiration pneumonia, bacteremia, conjunctivitis, omphalitis, and infant botulism. The failure to direct adequate therapy against these organisms may lead to clinical failures. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens. Treatment of anaerobic infection is complicated by the slow growth of these organisms, by their polymicrobial nature, and by the growing resistance of anaerobic bacteria to antimicrobials. Antimicrobial therapy is often the only form of therapy required, whereas in others it is an important adjunct to a surgical approach. Because anaerobic bacteria generally are recovered mixed with aerobic organisms, the choice of appropriate antimicrobial agents should provide for adequate coverage of both types of pathogen.

Aspiration pneumonia is an important and frequent complication following aspiration of infectious material from the oropharynx or stomach. Therefore the microbiological flora generally comprises a mixed spectrum of microbes including aerobic, microaerobic and anaerobic mircoorganisms. There are a number of risk factors for aspiration such as compromised consciousness or esophageal diseases. Aspiration pneumonia presents as a subacute or chronic disease. An endoscopic inspection of the bronchial system and a bacteriological evaluation should be performed in all patients. The principal therapeutic strategy for aspiration pneumonia is an antibiotic therapy. In uncomplicated cases a treatment for 7-10 days should be sufficient, but in case of complications like necrotizing pneumonia or lung abscess a prolonged administration (14-21 days, up to weeks or months) will be necessary. Recommended antibiotic regimens include clindamycin +/- cephalosporin, ampicillin/sulbactam and moxifloxacin.

Pneumonia complicates the course of 50% of patients on mechanical ventilation, requiring three or more days of mechanical ventilation and potentially increasing the relative risk of mortality by 20-40%. The predominant potentially pathogenic micro-organisms are Streptococcus pneumoniae, Staphylococcus aureus (sensitive to methicillin in the previously healthy host), Pseudomonas aeruginosa (aerobic gram-negative bacilli), and methicillin-resistant Staphylococcus aureus in the host with underlying disease. Approximately 85% of pneumonias are endogenous, caused by bacteria present in the patient's oropharyngeal flora. Bacteria present on admission cause primary endogenous pneumonia (55%), whereas bacteria acquired in the unit lead to supercarriage or secondary carriage and subsequently secondary endogenous pneumonia (30%). The remaining 15% are exogenous, ie the bacteria causing pneumonia are not carried by the patient. The diagnosis is usually based on clinical, radiological, and microbiological criteria, using the non-invasive method of tracheal aspirate, which yields >/=10(5) micro-organisms. Seven randomized trials have evaluated three non-antibiotic prophylactic maneuvers: hygiene (1 trial), subglottic drainage (4 trials), and semirecumbent position (2 trials). The impact on pneumonia was mixed, whereas mortality was unchanged. Selective digestive decontamination, using parenteral and enteral antimicrobials to control the three types of pneumonia, has been evaluated in 54 trials and showed an absolute mortality reduction of 8%. The therapy of pneumonia relies on six basic principles: (a) surveillance and diagnostic cultures to identify micro-organisms; (b) immediate and adequate antibiotic treatment to sterilize the lower airways, (c) the source of potential pathogens requires elimination for recovery of the original infection and prevention of relapses and/or superinfections; (d) aerosolized antimicrobials; (e) removal or replacement of the endotracheal tube; and (f) surveillance samples are indispensable to monitor efficacy of treatment. The aim of our review was to evaluate up to date facts regarding control of bacterial pneumonias during mechanical ventilation in intensive care unit settings.

Pulmonary infections due to anaerobic bacteria usually occur in children prone to aspiration. The source of the anaerobic bacteria is the oropharyngeal bacterial flora, where these organisms outnumber aerobic and facultative organisms in a 10:1 ratio. The most common lower respiratory tract infections where anaerobic bacteria are recovered mixed with aerobic organisms are aspiration pneumonia, lung abscess, and empyema. The predominant isolated anaerobic bacteria are Peptostreptococcus, Fusobacterium, pigmented Prevotella, and Porphyromonas spp. and Bacteroides fragilis group. Management of these infections includes the administration of antimicrobials effective against the anaerobic as well as the aerobic pathogens.

Colonization of the tracheobronchial tree with microorganisms almost always follows tracheal intubation, tracheostomy, or the use of ventilatory tubes. Infection of the tracheostomy wound site frequently occurs after prolonged use of the tracheostomy. The long-term-ventilated child is at high risk for developing tracheobronchitis or nosocomial pneumonia, generally involving aerobic gram-negative or gram-positive bacteria. Several studies have illustrated the role of anaerobic bacteria in lower respiratory tract and tracheostomy wound site infection in intubated children. The predominant anaerobic bacteria were Peptostreptococcus spp and pigmented Prevotella and Porphyromonas spp. Most of these infections are due to polymicrobial aerobic-anaerobic bacterial flora. Appropriate management of mixed pulmonary aerobic and anaerobic infections requires the administration of antimicrobials that are effective against both the aerobic and anaerobic components of the infection.

The authors studied the bacterial flora of the dog oral cavity and of bite wounds, Aerobic bacteria were isolated from mouth swabs of 16 normal and 5 rabid dogs as well as from infected dog-bite wounds from 18 patients. A total of 20 different microbial species were recovered from mouth swab cultures. The most frequently isolated organisms were Klebsiella pneumoniae ssp pneumoniae, Escherichia coli, Staphylococcus aureus, Citrobacter freundii, Enterobacter cloacae, Acinetobacter calcoaceticus, and Pasteurella species. There were no differences in the aerobic bacterial flora between rabid and nonrabid dogs. From the cultures of the bite wound swabs, the authors found that almost all of the organisms identified were part of the normal oral flora of the dog. One or more aerobic bacteria were isolated from the infected dog-bite wounds. Two patients had four, 3 had three, 4 had two, and 6 had one of the nine organisms in their wounds. The predominant species of bacteria involved in infection of bite wounds were, as follows: Staphylococcus aureus, Pasteurella multocida, E. coli, Moraxella species, Pasteurella canis, and Enterobacter cloacae. However, three wound cultures had no aerobic bacterial growth. The results of this study show that the infected bite wounds may contain a mixed bacterial flora that colonize human skin and the oral cavity of dogs.

Anaerobic bacteria are predominant components of normal oral cavity, upper respiratory tract, gastrointestinal, genital and skin flora. They are involved in infections such as pneumonia, aspiration pneumonia, lung abscess and empyema. Laboratory diagnosis of anaerobic infections is based on recovering the etiological agents from clinical materials. Appropriatte specimens include: pus, purulent fluid, biopsy specimen of lung, transtracheal aspirates and bronchoalveolar lavage (BAL). Lower respiratory infections are usually either polymicrobial or mixed anaerobic-aerobic infections. Peptostreptococcus, Fusobacterium, Prevotella and Bacteroides are the most common anaerobes. Anaerobic bacteria are susceptible to metronidazole, tinidazole (exception of Gram-positive rods), amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin/tazobactam, imipenem and clindamycin. Treatment includes an antibiotics regimen with an agent active against anaerobic and aerobic bacteria (therapy with 2 or 3 antimicrobial drugs).

Anaerobic bacteria commonly cause infection in children. Anaerobes are the most predominant components of the normal human skin and mucous membrane bacterial flora, and are therefore a common cause of bacterial infections of endogenous origin. Because of their fastidious nature, they are difficult to isolate from infectious sites and are often overlooked. Anaerobic infections can occur in all body sites, including the central nervous system, oral cavity, head and neck, chest, abdomen, pelvis, skin, and soft tissues. Anaerobic bacteria colonize the newborn after delivery and have been recovered from several types of neonatal infections. These include cellulitis of the site of fetal monitoring, neonatal aspiration pneumonia, bacteremia, conjunctivitis, omphalitis, and infant botulism. The lack of directing adequate therapy against these organisms may lead to clinical failures. Their isolation requires appropriate methods of collection, transportation, and cultivation of specimens. Treatment of anaerobic infection is complicated by the slow growth of these organisms, by their polymicrobial nature, and by the growing resistance of anaerobic bacteria to antimicrobials. Antimicrobial therapy is often the only form of therapy required, whereas in other cases it is an important adjunct to a surgical approach. Because anaerobic bacteria generally are recovered mixed with aerobic organisms, the choice of appropriate antimicrobial agents should provide for adequate coverage of both types of pathogens.

Relatively simple objective criteria are now available to predict which patients are at risk for bad outcomes from community-acquired pneumonia. In general, these include older patients and those with certain coexisting illnesses (especially neoplastic disease) or findings of altered mental status, hypotension, severe tachycardia, tachypnea, fever, acidemia, azotemia, hypoxemia, hyperglycemia, anemia, or hyponatremia. The major causes of severe pneumonia are S pneumoniae, H influenzae, and L pneumophila. Less common causes include mixed aerobic and anaerobic mouth flora, as well as M pneumoniae, C pneumoniae, gram-negative bacilli, and S aureus. Specific diagnosis is hampered by a lack of reliable diagnostic tests, but Gram's stain of expectorated sputum and cultures of sputum and blood may occasionally be helpful. Many empirical treatment regimens have been recommended, including those of the American Thoracic Society and the Infectious Diseases Society of America, which are reviewed here. It is hoped that better diagnostic tools will permit future targeting of microbes with narrow-spectrum therapy to diminish the risk of selection of resistant strains with empirical regimens.

Clinical and laboratory data from 1973 to 1988 were retrospectively reviewed to study the microbiology of infection following trauma. A total of 368 specimens obtained from 340 trauma patients showed bacterial growth. The traumas included lacerations (163), blunt trauma (76), penetrating trauma (65), bites (20), and open fractures (10). Anaerobic bacteria only were isolated in 119 (32%) specimens, aerobic bacteria only in 58 (16%), and mixed aerobic-anaerobic flora in 191 (52%). A total of 444 anaerobic (1.2 isolates per specimen) and 267 aerobic or facultative (0.7 per specimen) were recovered. The predominant anaerobic bacteria included Bacteroides fragilis group (119 isolates), Peptostreptococcus spp (113), Clostridium spp (78), Prevotella spp (58), and Fusobacterium spp (23). The predominant aerobic bacteria included Escherichia coli (83), Staphylococcus aureus (61), Streptococcus pyogenes (27), Streptococcus group D (16), and Klebsiella pneumoniae (16). The types of infections included abscesses (109), bacteremia (32), bites (13), empyema (10), osteomyelitis (21), peritonitis (52), thrombophlebitis (12), and wounds (116, including posttraumatic wounds, cellulitis, stump wound, decubitus ulcers, myositis, and fasciitis). S. aureus was isolated at all sites. However, organisms of the oropharyngeal flora predominated in infections that originated from that location (ie, head and neck wounds, and abscesses or bites), and those of the gastrointestinal flora predominated in infections that originated from that site (ie, peritonitis, abdominal abscesses, decubitus ulcers). This study showed the polymicrobial nature of many infections that follow trauma.

The goal of this work was to study the microbiology and clinical characteristics of patients with infections associated with malignancy treated over a period of 17 years. A total of 668 specimens were obtained from 605 patients. The malignancies include 224 hematological malignancies and 381 nonhematogenic malignancies. Anaerobic bacteria only were isolated in 201 (30%) specimens, aerobic bacteria in 226 (34%), mixed aerobic-anaerobic bacteria in 231 (35%) and Candida spp. in 10 (1%). A total of 683 anaerobic (1.0 isolates per specimens) and 592 aerobic or facultative (0.9 per specimen) organisms were recovered. The predominant anaerobic bacteria included Bacteroides fragilis group isolates (181), Peptostreptococcus spp. (166), Prevotella spp. (106), Clostridium spp. (70), and Fusobacterium spp. (43). The predominant aerobic bacteria included Escherichia coli (133), Staphylococcus aureus (100), Klebsiella pneumoniae (48), and Pseudomonas aeroginosa (45). The type of infections included abscesses (221), bacteremia (198), wounds (175), including 61 cellulitis, 24 post-surgical wounds and 23 decubitus ulcers), peritonitis (48), empyema (12), cholecystitis (6) and thrombophlebitis (5). S. aureus and Peptostreptococcus spp. were isolated from all sites. However, organisms of the oropharyngeal flora (Prevotella and Fusobacterium spp.) predominated in local infections and bacteremia that originated from this site (head and neck wounds and abscesses and pulmonary infections), and organisms of the gastrointestinal tract flora predominated in infections that originated from this site (peritonitis, abdominal abscesses and decubitus ulcers). This retrospective study demonstrates polymicrobial features of many infections associated with malignancies.

Microbiological and clinical data from 56 patients with endodontic infections were evaluated. Samples were collected using autoclaved paper points. Specimens were processed for isolation of aerobic and anaerobic bacteria. Antimicrobial sensitivity and resistance profiles of the recovered isolates was also performed. Forty nine positive cultures (87.5%) were obtained from the 56 consecutive necrotic root canal systems which were sampled. A total of 69 aerobic bacteria and 21 anaerobic bacteria were recovered. Aerobic bacteria were isolated from 35 patients (72%), anaerobic bacteria from 3 (6%) and mixed aerobic and anaerobic bacteria from 11 patients (22%). The most common aerobic isolate was Klebsiella pneumoniae. The predominant anaerobic isolate was Bacteroides species. One isolate was recovered from 25 patients (51%) whereas in the remaining 24 patients (49%) more than 1 isolate were recovered. These data illustrate the polymicrobial nature of endodontic infections in half the patients studied and the role of anaerobic bacteria in a quarter of them.

The paper presents the views on the etiology of infections in the respiratory system. Beside the so called "old pathogens" such as Streptococcus pneumoniae, Haenophilus influenzae, Moraxella catarrhalis, "atypic" microorganisms are becoming more and more important, i.e. Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia pneumoniae. Mixed flora with aerobic and anaerobic bacteria is observed in chronic infections. Viral infections facilitate bacterial infections. Antibiotic used first should be active against the "old" and "new" pathogens. Future prospects are set on macrolides such as clarythromycin.

The quantitative aerobic and anaerobic microbiology of bronchial aspirates, obtained using protective brush catheters, from 10 children with ventilator-associated pneumonia, is presented. Aerobic or faculative organisms only were isolated in 1 child, anaerobic bacteria only in 3, and aerobic mixed with anaerobic bacteria in 6. There were 10 aerobic or faculative and 17 anaerobic isolates. The predominant aerobes were Pseudomonas aeruginosa (2 isolates) and Klebsiella sp. (2). The predominant anaerobes were pigmented Prevotella and Porphyromonas species (5), Peptostreptococcus sp. (4), Fusobacterium sp. and B. fragilis group (2). A total of 10 beta-lactamase-producing aerobic and anaerobic bacteria were isolated in 8 patients. All patients except 1 responded to antimicrobial therapy directed against the recovered isolates. These data highlight the polymicrobial aerobic-anaerobic flora isolated from pulmonary specimens of patients with ventilator-associated pneumonia.

The aerobic and anaerobic microbiology of 38 children from Surabaya, Indonesia, who suffered from chronic suppurative otitis media (CSOM) was studied using strict microbiological methodology. A total of 106 isolates (49 anaerobic and 57 aerobic) were recovered. Aerobic organisms alone were isolated from 11 (29%), anaerobic bacteria only in 4 (11%) and mixed aerobic and anaerobic flora were present in 23 (60%). The predominant organisms were Peptostreptococcus sp., Prevotella sp., Bacteroides sp., Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and Fusobacterium sp. Thirty-nine beta-lactamase-producing bacteria were recovered from 22 (58%) patients. These findings demonstrate the role of penicillin resistant aerobic and anaerobic bacteria in the polymicrobial etiology of CSOM in children from Indonesia. Judicious use of antimicrobial therapy may prevent the development of antimicrobial resistance.

Aspiration is the leading cause of anaerobic lung infections. Risk factors for these infections include a depressed level of consciousness, a history of seizure, general anesthesia, central nervous system or neuromuscular disease, cerebrovascular accident, impaired swallowing and use of a tracheal or nasogastric tube. Clinical presentation includes fever, weight loss, malaise and cough productive of foul-smelling sputum. Diagnosis is based on radiographic findings, clinical features and a characteristic morphology of mixed flora on Gram stain of uncontaminated pulmonary specimens. The diagnosis is confirmed by isolation of organisms, usually polymicrobial, on culture. Treatment includes proper drainage, debridement of necrotic tissue and an antibiotic regimen (often initially empiric) with an agent active against anaerobic and aerobic organisms.

Cultures of paronychia of the fingers have grown aerobic and anaerobic bacteria. Each was recovered individually in only about a quarter of the patients and a mixed aerobic/anaerobic flora was isolated in half of the patients. The predominant anaerobic organisms were Gram-positive anaerobic cocci, Bacteroides species and Fusobacterium species. The predominant aerobic organisms were Staphylococcus aureus, gamma-haemolytic streptococci, Eikenella corrodens, group A beta-hemolytic streptococci, alpha-hemolytic streptococci, and Klebsiella pneumoniae. Candida albicans was recovered in about 15% of the cases. The management of this infection is discussed.

Bronchial aspirates collected from a group of 100 patients with respiratory infections undergoing broncho-fiberscopic examination have been tested bacteriologically. Twenty five patients was suffered from bronchopneumonia, 35 patients have had acute bronchitis, and 40 patients chronic bronchitis. Aerobic bacterial flora has been detected in 15% of patients, anaerobic flora in 13%, an mixed bacterial flora in 20%, totally in 48% of cases. Aerobic bacteria predominated in pneumonia. Bacteroides melaningogenicus prevailed in anaerobic flora. The tests of bacterial sensitivity to antibiotics have shown high sensitivity to cefotaxime, cefamandole, metronidazole, and rifampicin.

For optimal prevention of infection subsequent to a surgical intervention, it is necessary to follow a series of general principles, including the classification of the type of surgical intervention, the characteristics of the antibiotic used, and the route and the time of its administration. Moreover, with reference to the different types of surgery, other factors assume importance: the etiology of the infection and the ability of the antibiotic to achieve adequate levels in the tissues at the beginning of the infective process. In general abdominal, biliary, and obstetric-gynecologic surgery, which covers many clean-contaminated and contaminated interventions for which antibiotic prophylaxis has been shown to be the most effective, the etiology is often mixed (aerobic and anaerobic flora) with a predominance of gram-negative microorganisms. Thus, an appropriate prophylactic regimen must consider a third-generation cephalosporin, such as cefotaxime, that is effective against most gram-negative bacteria, in particular against Klebsiella pneumoniae. Acylureido penicillins can also be used because of their activity against enterococci, gram-positive microorganisms that are also causes of infection in this area of surgical intervention. Combining an antimicrobial such as clindamycin or metronidazole, which are particularly active against anaerobes, may be recommended as well. In urologic surgery, most infections are caused by Enterobacteriaceae; in addition to the antimicrobial spectrum, the ability of the antibiotic to concentrate adequately in the urine and renal tissue must also be considered. Beta-lactam antibiotics are the agents of choice, in particular, third-generation cephalosporins, aztreonam, and acylureido penicillins. In cardiac, orthopedic, and partially in neurologic surgery, where most infections are due to gram-positive bacteria (primarily methicillin-resistant staphylococci), antibiotic prophylaxis should include a glycopeptide agent (teicoplanin, vancomycin). In the field of surgical prophylaxis, more experience has been accumulated with cefotaxime, used as a short-course regimen or as a convenient single dose, than with any other newer cephalosporin. Cefotaxime's broad spectrum of action provides coverage against most potential pathogens and, when used as a single dose, is both convenient and cost-effective.

In summary, the selection of a specific antimicrobial agent for the treatment of infections caused by anaerobic microorganisms depends upon the site of infection, the suspected anaerobic and aerobic microorganisms causing the infection, and the pharmacokinetics and drug distribution of the antimicrobial agent. Appropriate surgical debridement or drainage of abscess material is as important, if not more so, than the selection of a specific antimicrobial agent for the successful management of patients with infections caused by anaerobic microorganisms. The availability of new antimicrobials with activity against anaerobic microorganisms, and combination therapy for managing infection caused by mixed flora of aerobic and anaerobic microorganisms, has increased our ability to successfully manage hospitalized patients with infections caused by these microorganisms.