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.