Infection polymicrobial

It is often difficult to narrow the spectrum of activity of the antibiotic choice since the infections are usually polymicrobial. As such, patients may receive long courses of broad-spectrum antibiotics such as imipenem/cilastatin and... 

Cellulitis is a bacterial infection of the dermis and subcutaneous tissue. S. aureus and P-hemolytic streptococci are the most common causes of acute cellulitis in otherwise healthy hosts. Persons who are immunocompromised, have vascular insufficiency, or use injection drugs are at risk for polymicrobial cellulitis. 

The pathogenesis of diabetic foot infection stems from three key factors neuropathy, angiopathy, and immunopathy. Aerobic gram-positive cocci, such as S. aureus and P-hemolytic streptococci, are the predominant pathogens in acutely infected diabetic foot ulcers. However, chronically infected wounds are subject to polymicrobial infection and require treatment with broad-spectrum antibiotics. 

Injection drug use also predisposes individuals to polymicrobial cellulitis. The antecubital region of the arm is usually the site of infection. S. aureus, the most common isolate, is frequently associated with abscess formation. Because some injection drug users lick their needles to clean them, antibiotics with anaerobic coverage should be used. Occasionally, Candida spp. are isolated, and the patient may require antifungal therapy.18... 

Pressure sore infections develop from breaks in skin integrity and contamination from dirty areas of close proximity. Pressure sore infections generally are polymicrobial.39... 

Systemic antibiotics are indicated for pressure sores associated with spreading cellulitis, osteomyelitis, or bacteremia. Because the infections usually are polymicrobial, antibiotic therapy should target gram-positive, gram-negative, and anaerobic bacteria. The duration of treatment is generally 10 to 14 days, unless osteomyelitis is present.38... 

I Bite-wound infections generally are polymicrobial. On average, five different bacterial species can be isolated from an infected animal bite wound.3 Both the normal flora of the biter s mouth and that of the bite recipient s skin can be implicated. The bacteriology of the cat and dog mouth is quite similar. Pasteurella multocida, a gram-negative aerobe, is one of the predominant pathogens, isolated in up to 50% of dog and 75% of cat bites. S. viridans are the most frequently cultured bacteria from human bite wounds.3,43 Table 70-10 provides a comprehensive list of cat, dog, and human bite-wound pathogens. 

Because of the diverse bacteria present in the GI tract, secondary intraabdominal infections are often polymicrobial.12 The mean number of different bacterial species isolated from infected intraabdominal sites ranged from 2.9 to 3.7, including an average of 1.3 to 1.6 aerobes and 1.7 to 2.1 anaerobes.13 14... 

Most infections are polymicrobial, and the most frequently isolated organisms are Pasteurella spp., streptococci, staphylococci, Moraxella, and Neisse-... 

Open/compound fractures Neurosurgery 5. aureus, S. epidermidis, gram-negative bacilli, polymicrobial Cefazolin 1 gx 1 preoperatively, then every 8 hours for a course of presumed infection Gram-negative coverage (i.e, gentamicin) often indicated for severe open fractures IA... 

Imipenem-cilastatin is one of the drugs of first choice for the empirical therapy of many polymicrobial pulmonary, intraabdominal, and soft tissue infections. The notable adverse effect of imipenem-cilastatin is seizures affecting 1% of patients. Risk factors for seizures are old age, head trauma, previous seizure disorder, cerebrovascular accident, and renal failure. Among patients with a history of penicillin allergy, 10% are cross-sensitive to imipenem-cilastatin. 

Acute salpingitis (pelvic inflammatory disease) due to Neisseria gonorrhoeae. Chlamydia trachomatis, or both is often complicated by superinfection with gramnegative bacilli and anaerobes. A combination of gentamicin, clindamycin, and doxycycline has been shown to be an effective treatment for this polymicrobial infection. 

To treat polymicrobial infections such as intra-abdominal abscesses. The antimicrobial combination chosen should cover the most common known or suspected pathogens but need not cover all possible pathogens. The availability of antimicrobials with excellent polymicrobial coverage (eg, 13-lactamase inhibitor combinations or imipenem) may reduce the need for combination therapy in the setting of polymicrobial infections. 

Opal, S.M. Palardy, J.E. Chen, W.H., Parejo, N.A., Bhattacharjee, A.K., Cross, A.S, Active immunization with a detoxified endotoxin vaccine protects against lethal polymicrobial sepsis Its use with CpG adjuvant and potential mechanisms. J Infect Dis 192 (2005) 2074-2080. 

Combination therapy is often used when dealing with infections caused by both aerobic and anaerobic bacteria [50,80]. Combination of metronidazole with either gentamicin or ciprofloxacin appeared to be effective in preventing infection of abdominal trauma [101] when combined with ciprofloxacin, metronidazole was affective as a preoperative antibiotic in colorectal surgery and appeared equal in efficacy to impipenem/cilastin for the treatment of complicated intraabdominal infections [103]. Combination therapy is not always indicated for the treatment of polymicrobial infections. New antibiotics, whose spectrum includes multiple classes of microorganisms (e.g., imipenem), may often preclude combination therapy. 

Case Conclusion Because the etiology of intra-abdominal infections is most often polymicrobial (gram-negative and anaerobic bacteria) and the patient has an allergy to penicillin, FD can be treated empirically with tobramycin and metronidazole or clindamycin. This regimen provides adequate empiric coverage of the most noteworthy pathogens associated with intra-abdominal infections. 

Combination antibiotic therapy may be indicated for polymicrobial infections (abdominal, gynecologic infections), to produce synergistic killing ( 8-lactam plus aminoglycoside versus Pseudomonas aeruginosa), or to prevent the emergence of resistance. 

A variety of factors may be responsible for an apparent lack of response to therapy. ° Patients who fail to respond over 2 to 3 days require a thorough reevaluation. It is possible that the disease is not infectious or is nonbacterial in origin, or there is an undetected pathogen in a polymicrobial infection. Other factors include those... 

Infections from dog bite wounds are caused predominantly by organisms documented to be from the dog s oral flora. Most infections are polymicrobial, with approximately five bacterial isolates per culture. Pasteurella species are the most frequent isolates. Other common aerobes include streptococci, staphylococci, Moraxella, and Neisseria. The most common anaerobes are Fusobacterium, Bacteroides, Porphyromonas, and Prevotella Wound-site cultures in both infected and noninfected patients have similar bacteria present, with aerobic organisms isolated from 74% to 90% and anaerobic organisms isolated from 41% to 49%. ... 

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