Specific Antimicrobial Therapy Research Articles

Foodborne Infections

This review provides a practical and simple clinical approach to the diagnosis and management of foodborne infections. Most episodes of acute diarrhea are self-limited, and investigations should be performed only if the results will influence management and outcome. After history taking and physical examination, the clinical should be able to classify the acute diarrheal illness, assess the severity, and determine whether investigations are needed. Most patients do not require specific antimicrobial therapy. Therapy should be directed mainly at preventing dehydration. Oral rehydration solutions suffice in mild, self-limited diarrhea, as they are formulated to stimulate sodium and water absorption. However, intravenous hydration therapy is required in diarrheal patients with severe dehydration. Antibiotic therapy is required in dysentery.

Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the Steris System 1 processor.

To assess nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa (IRPA) following bronchoscopy during August through October 1998. Traditional and molecular epidemiological investigation of a case series. University-affiliated community hospital. 18 patients with IRPA bronchial-wash isolates. We reviewed clinical data, performed environmental cultures and molecular analysis of all IRPA isolates, and observed disinfection of bronchoscopes. Of 18 patients who had IRPA isolated from bronchoscopic or postbronchoscopic specimens, 13 underwent bronchoscopy for possible malignancy or undiagnosed pulmonary infiltrates. Following bronchoscopy, 3 patients continued to have IRPA isolated from sputum and demonstrated clinical evidence of infection requiring specific antimicrobial therapy. The remaining 15 patients had no further IRPA isolated and remained clinically well 3 months following bronchoscopy. Pulsed-field gel electrophoresis revealed that all strains except one were >95% related. STERIS SYSTEM 1 had been implemented in July 1998 as an automatic endoscope reprocessor (AER) for all endoscopes and bronchoscopes. Inspection of bronchoscope sterilization cycles revealed incorrect connectors joining the bronchoscope suction channel to the STERIS SYSTEM 1 processor, obstructing peracetic acid flow through the bronchoscope lumen. No malfunction warning was received, and spore strips remained negative. The similarity of diverse connectors and limited training by the manufacturer regarding AER for bronchoscopes were the two factors responsible for the outbreak. Appropriate connections were implemented, and there was no further bronchoscope contamination. We suggest active surveillance of all bronchoscopy specimen cultures, standardization of connectors of various scopes and automated processors, and systematic education of staff by manufacturers with periodic on-site observation.

Acute Pharyngitis

The primary care physician needs to identify those patients with acute pharyngitis who require specific antimicrobial therapy and to avoid unnecessary and potentially deleterious treatment in the large majority of patients who have a benign, self-limited infection that is usually viral. In most cases, differentiating between these two types of infection can be accomplished easily if the physician considers the epidemiologic setting, the history, and the physical findings, plus the results of a few readily available laboratory tests. When antimicrobial therapy is required, the safest, narrowest-spectrum, and most cost-effective drugs should be used. Despite agreement on these principles by expert advisory committees, data from national surveys of ambulatory care indicate that antimicrobial agents continue to be prescribed indiscriminately for upper respiratory infections.

A Clinical Investigation of Community-Acquired Pneumonia in Mokpo Area

Background Community-acquired pneumonia(CAP) remains a leading cause of morbidity and mortality worldwide. Recently, the evolution of drug-resistant microorganisms has become a serious problem in CAP management. Specific antimicrobial therapy is the cornerstone of CAP management. However, obtaining an accurate etiologic diagnosis clinically is not easy and empirical antimicrobial treatment is usually administered prior to the correct microbiologic diagnosis. In this study, the clinical usefulness of empirical CAP treatment was investigated. Methods A total 35 cases were studied prospectively over a 16-month period in Mokpo Catholic Hospital from Dec. 1995 to Mar. 1997. The microbiologic diagnosis was made by sputum, blood culture, a specific serum antibody test and an immunologic study. Results The causative organisms were isolated in 10 (30%) out of 33 cases: 8 cases and 1 case on the sputum culture and blood culture respectively, and 1 case by an indirect hemagglutinin test. 12 cases had underlying diseases: pulmonary tuberculosis 4, alcoholism 4, diabetes mellitus 3, and liver cirrhosis 1. Antimicrobial treatment was given empirically and all cases recovered. Conclusion A definite microbiologic diagnosis before commencing the appropriate treatment in CAP is not straightforward. Empirical therapy according to a clinical assessment is important and helpful. However, every effort to make the correct etiologic diagnosis should be taken.

Syphilitic neuroretinitis, a report of three cases and review of literature

Acquired syphilis has a propensity to affect any of the ocular tissues including the optic nerve. With the present AIDS epidemic, the prevalence of concurrent syphilis is on the increase. It is important to recognize syphilitic involvement of the optic nerve in its earlier stages, because specific and effective antimicrobial therapy is available. As syphilitic neuroretinitis does not have any characteristic clinical pattern and VDRL has only a low sensitivity in ocular syphilis, the condition is often treated initially with systemic corticosteroids. Such a situation could be avoided by eliciting a detailed and careful history, performing meticulous evaluation for systemic signs such as skin involvement, and repeating the VDRL test for syphilis. In this report, we describe three cases of neuroretinitis in which the diagnosis of syphilis was initially missed and all cases were treated with systemic corticosteroids. We discuss reasons for such a delayed diagnosis and also present a review of the literature.

Diarrea por adenovirus y astrovirus en pacientes inmunodeficientes hospitalizados

Acute or chronic diarrheal illness are common complications in immunosuppressed patients such as human immunodeficiency virus (HIV)-infected, bone marrow or solid organ transplanted patients and those with leukaemias or other immune deficiency disorders. Due to the importance of recognizing the feasible etiologies of diarrhea in order to give the proper antimicrobial chemotherapy or to avoid a misdiagnosis of rejection in the case of transplanted patients, we have investigated adenovirus and astrovirus antigen in faeces from different immunosuppressed patients. Stool samples from 258 immunodeficient patients hospitalized at University Hospital Complex of Santiago of Compostela with acute or persistent diarrhea were collected between 1997-99 and assayed for astrovirus and adenovirus antigen. Viral antigen was detected by EIA. Other common enteric pathogens were also assayed. Adenovirus antigen was positive in 5 cases (2%) and astrovirus antigen in 12 cases (5%). The most commonly patients infected was those with haematologic disorders and premature infants. HIV-infected patients were positive for astrovirus antigen in 3 cases. The majority of the cases were related with intestinal bacterial diseases or other circumstances, such as Clostridium difficile infection, both associated with prolonged antimicrobial therapy. Astrovirus and adenovirus have to be considered as enteropathogens specially in immunocompromised hospitalized patients. An accurate diagnosis about diarrhea etiology is advisable in order to give a specific antimicrobial therapy, when it be necessary, or to avoid a misdiagnosis of rejection, in transplanted patients.

Canine Rickettsial Infections

Dogs that live in tick-infested areas are at risk for contracting rickettsial infections. Clinical signs associated with ehrlichiosis or Rocky Mountain spotted fever may be dramatic or mild. Clinicians must consider the possibility of rickettsial diseases to request laboratory tests that will permit a proper diagnosis. Specific antimicrobial therapy usually brings about clinical improvement, although some dogs may not be cleared of rickettsial organisms, even with prolonged treatment. A small percentage of dogs die of rickettsial infections, either in the acute stage or owing to chronic bone marrow suppression and generalized debilitation. Ocular lesions are an important clinical sign in canine rickettsial infections and may aid the clinician in making a diagnosis and monitoring response to therapy.

Etiology and Microbial Patterns of Pulmonary Infiltrates in Patients With Orthotopic Liver Transplantation

To evaluate the etiology and microbial patterns of pulmonary infiltrates in liver transplant patients using a bronchoscopic diagnostic approach and the impact of diagnostic results on antimicrobial treatment decisions. A prospective cohort study. A 1,000-bed tertiary-care university hospital. Fifty consecutive liver transplant patients with 60 episodes of pulmonary infiltrates (33 episodes during mechanical ventilation) were studied using flexible bronchoscopy with protected specimen brush (PSB) and BAL. A definite infectious etiology was confirmed in 29 episodes (48%). Eighteen episodes corresponded to probable pneumonia (30%), 10 episodes had noninfectious etiologies (17%), and 3 remained undetermined (5%). Opportunistic infections were the most frequent etiology (16/29, 55%, including 1 mixed etiology). Bacterial infections (mainly Gram-negative) accounted for 14 of 29 episodes (48%), including 1 of mixed etiology. The majority of bacterial pneumonia episodes (n = 10, 71%) occurred in period 1 (1 to 28 days posttransplant) during mechanical ventilation, whereas opportunistic episodes were predominant in periods 2 and 3 (29 to 180 days and > 180 days posttransplant, respectively; n = 14, 82%). Microbial treatment was changed according to diagnostic results in 21 episodes (35%). Microbial patterns in liver transplant patients with pulmonary infiltrates corresponded to nosocomial, mainly Gram-negative bacterial pneumonia in period 1, and to opportunistic infections in period 2 and, to a lesser extent, period 3. A comprehensive diagnostic evaluation including PSB and BAL fluid examination frequently guided specific antimicrobial therapy.

Bone and joint infections in the elderly: practical treatment guidelines.

Two types of haematogenous osteomyelitis that are seen in the elderly are vertebral and long bone osteomyelitis. Osteomyelitis secondary to contiguous foci of infection can occur in older adults without vascular insufficiency (secondary to pressure ulcers) or with vascular insufficiency due to diabetes mellitus or peripheral vascular disease from atherosclerosis. Most cases of osteomyelitis can be reasonably treated with adequate drainage, thorough debridement, obliteration of dead space, wound protection, and antimicrobial therapy. Patients are initially given a broad spectrum antimicrobial that is changed to specific antimicrobial therapy based on meticulous bone cultures taken at debridement surgery or from deep bone biopsies. Surgical management is often required in the treatment of osteomyelitis and includes adequate drainage, extensive debridement of all necrotic tissue, obliteration of dead spaces, stabilisation, adequate soft tissue coverage, and restoration of an effective blood supply. Bone repair and bone mineral density may be significantly retarded and may be corrected by eliminating risk factors, supplementing the diet with calcium, bisphosphonates, and/or vitamin D, and treating with testosterone and/or estrogen when deficient. Sodium fluoride treatment and anabolic steroids may be used as alternatives. Septic arthritis is a medical emergency, and prompt recognition and rapid and aggressive treatment are critical to ensuring a good prognosis. The treatment of septic arthritis includes appropriate antimicrobial therapy and joint drainage. Adverse effects of prescribed antibacterials occur more often in the elderly patient than in young adults. The physician can help to minimise the incidence of adverse effects and improve outcomes by being aware of the principles of clinical pharmacology, the characteristics of specific drugs, and the special physical, psychological and social needs of older patients.

Brucellosis in Saudi Arabia: Past, Present and Future

Brucellosis in Saudi Arabia: Past, Present and Future

Rhabdomyolysis and Acute Renal Failure in a Case of Child Abuse

The most common manifestations of child abuse are skin lesions, such as ecchymoses, abrasions, scars and burns. Bone fractures, failure to thrive, subdural and retinal hemorrhage, genital injuries, subgaleal hematoma, unkempt appearance, frozen stares, human bite marks, visceral injuries, etc., are additional manifestations. Munchausen syndrome by proxy is a rare presentation which has recently been well described in the literature. Various unusual manifestations of child abuse, such as fetal pepper aspiration, thirsting and hypernatremic dehydration, intentional microwave burns, transection and pseudocyst of the pancreas, tin ear syndrome, subcutaneous fat necrosis, etc., have also been recognized recently. These unusual symptoms deceive clinicians and prevent early diagnosis, thus endangering the life of the victim. There are very few reports in the world literature on the association of child abuse and acute renal failure induced by rhabdomyolysis. To our knowledge, this is the first confirmed case of child abuse with acute renal failure due to rhabdomyolysis in Saudi Arabia.

Octreotide in the Treatment of Refractory Diarrhea

Refractory chronic diarrhea that does not respond to specific antimicrobial therapy or standard unspecific medication may present a challening and serious clinical problem. Octreotide is a candidate drug for the treatment of these patients as it inhibits gastrointestinal motility, pancreatic secretion and inhibits intestinal absorption. Only few mostly uncontrolled studies in small patient groups were published evaluating the efficacy of octreotide in the treatment of patients with chemotherapy-induced diarrhea, short-bowel syndrome, AIDS-associated diarrhea and other conditions with chronic diarrhea not responding to standard treatment. Most of these studies are not conclusive as they yielded either negative or controversial results. Octreotide may be tried in the treatment of refractory diarrhea, in particular AIDS-associated diarrhea if patients do not respond to conventional treatment strategies. Well-designed controlled trials in large patient groups are needed in order to define the place of octreotide in the treatment of patients with refractory diarrhea.

Adult posttraumatic osteomyelitis of the tibia.

Posttraumatic tibial osteomyelitis results from trauma or nosocomial infection from the treatment of trauma that allows organisms to enter bone, proliferate in traumatized tissue, and cause subsequent bone infection. The resulting infection is usually polymicrobial. The patient may be classified using the May and the Cierny-Mader classification systems. The diagnosis is based on the isolation of the pathogen(s) from the bone, or blood cultures. Appropriate therapy of posttraumatic tibial osteomyelitis includes adequate drainage, thorough debridement, obliteration of dead space, stabilization when necessary, wound protection, and specific antimicrobial therapy.

Current practices for management of oral mucositis in cancer patients.

Many anticancer therapies induce oral mucositis, diminishing the patient's quality of life. Especially in neutropenic patients, it can lead to life-threatening systemic infection. Moreover, it can become a limiting factor in intensive treatment schedules. Many interventions are aimed at reducing trauma and the risk of secondary infection. The institution of good oral hygiene seems to play a crucial part and can be achieved manually or by means of antiseptic agents. More specific antimicrobial therapy may be indicated. In addition, local and/or systemic pain control may be required. The administration of hematological growth factors, cryoprotectants and other agents or measures that may be of help in the management of mucositis are discussed.

TREATMENT OF RETINAL VASCULITIS

Retinal vasculitis is an ocular finding that may represent a primary syndrome; may be part of an isolated ocular syndrome, such as birdshot chorioretinopathy; or may be a component of a systemic disease, such as Wegener's granulomatosis or multiple sclerosis. Regardless of the cause of the retinal vasculitis, there are some generalized treatment concepts that should be kept in mind. This article describes the authors' approach to the management of patients with retinal vasculitis. These general guidelines may somewhat vary depending on the underlying cause of the retinal vascular inflammation. As with other forms of uveitis, a stepwise treatment approach is offered. Not all patients with retinal vasculitis require therapeutic intervention. Therapy is probably indicated in a patient exhibiting any of the following symptoms: vision-limiting vitritis, capillary destruction around the foveal avascular zone, broad areas of capillary dropout, or cystoid macular edema. The following methods are discussed: observation, nonsteroidal antiinflammatory preparations, corticosteroids, and immunosuppressive agents. The role of surgical intervention is discussed, as well as some newer innovative approaches to the treatment of ocular inflammation. Certain conditions may vary from these generalized guidelines, and these are discussed later in the article. Before embarking on the use of any immunomodulating therapy, it is imperative for the clinician to have thoroughly evaluated the patient for the possibility of an infectious cause. This should have been done as part of the patient's history and ocular examination, as well as through the use of serologic studies, radiographs, and, if indicated, vitreous humor analysis. Bear in mind that the laboratory evaluation should be carefully guided by the results of a detailed medical history and review of organ systems. If this detailed history is negative then only a limited number of tests should be ordered.8 In most cases the laboratory shotgun approach will be both diagnostically unrewarding and expensive. If a specific infectious agent is identified, then specific antimicrobial therapy is indicated. If no infectious agent is found, then immunomodulating approaches may be indicated.

Diarrhea in Returning Austrian Tourists: Epidemiology, Etiology, and Cost-Analyses

Between 1995 and 1997, stool samples of 322 Austrian tourists returning from abroad with diarrhea were examined for bacteria, parasites and viruses. Epidemiologic data were collected from information furnished by physicians and hospitals and from questionnaires. Moreover, testing expenses and additional cost for treated cases were evaluated. In 97 of 322 patients examined (30%), one or more pathogens were detected in the stool. Bacteria were found in 38 patients (39%), parasites in 33 patients (34%) and viruses in 26 patients (27%). In 6 patients, mixed infections with parasites and viruses were detected and in 5 patients with bacteria and viruses. Among bacteria, Campylobacter jejuni was most frequent; among parasitic infections, Giardia lamblia. Significant correlations were established between the country of destination, age, travel style and length of stay. Forty-four percent of all patients visited Asia (including Turkey), 27% Africa, 18% Latin America, and only 10% southern Europe. The group between 20 and 29 years of age was most frequently affected (p<.001), the group between 0 and 19 years of age least. Fifty-seven percent stayed in a hotel without frequent changes of location; 43% undertook a trekking trip; and of those, 75% belonged to the group aged between 20 and 39. In terms of the correlation between travel style and pathogen, it was found that 74% of patients with bacterial infections stayed in a hotel (avg. 57.9%; p<.05) whereas 64% of all patients with parasitic infections undertook a trekking trip (avg. 42%; p<.001). Thirty-six percent of all patients with parasitic infections spent their vacation in India (avg. 13%; p<.001). The length of stay of patients with bacterial infections was shorter than average (72% spent between 1 and 2 weeks abroad, avg. 49.8%). Patients with parasitic infections spent significantly more time abroad than average (42% more than 2 months; avg. 17.7%; p<.001). Average cost of specific antimicrobial therapy was U.S.$31 whereas the average cost of identifying a patient needing such treatment was almost U.S.$580. Optimal detection rate and cost reduction for the diagnosis require precise history, adequate collection of samples using adequate transport media, and rapid transfer to the laboratory.

Infectious Crystalline Keratopathy Caused by Gram-negative Bacteria

To identify the characteristics and outcomes of infectious crystalline keratopathy caused by gram-negative bacteria. We reviewed all patients treated at a university eye center for infectious crystalline keratopathy from 1978 through 1995 and performed a nested case-comparison study by comparing patients with keratitis caused by gram-negative rods and those with keratitis caused by gram-positive cocci. Eighteen patients (mean age +/- SD, 59 +/- 17 years) displayed unilateral culture-positive infectious crystalline keratopathy. Among 18 eyes with crystalline keratopathy, five occurrences (28%) were caused by gram-negative rods (Acinetobacter lwoffi, Citrobacter koseri, Enterobacter aerogenes, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia), 10 (55%) were caused primarily by gram-positive cocci, and three (17%) were caused primarily by yeasts. Four cases grew two different isolates. No significant difference in predisposing factors, clinical appearance, or visual outcome was found between infections caused by gram-negative bacteria and those caused by gram-positive bacteria. Gram-negative bacteria can cause infectious crystalline keratopathy but have no distinguishing features from infectious crystalline keratopathy caused by streptococci and other gram-positive bacteria. Appropriate laboratory evaluation is therefore necessary to guide specific antimicrobial therapy.

Procalcitonin as a marker of bacterial sepsis in patients infected with HIV-1

Procalcitonin (ProCT) is a recently described marker of severe sepsis. It was decided to assess the value of proCT as a marker of secondary infection in patients infected with HIV-1. ProCT plasma levels were measured by immunoluminometric assay in a prospective study in 155 HIV-infected individuals: 102 asymptomatic and 53 with lever or suspected secondary infections. The baseline plasma level of ProCT was low (0.5 ng/ml +/- 0.37), even in the latest stages of the disease, and did not differ from the values of healthy subjects (0.54 ng/ml +/- 0.08). EDTA-treated whole blood was collected from patients before starting specific antimicrobial therapy. No elevation of ProCT level was detected in HIV-infected patients with evolving secondary infections including PCP (n = 4), cerebral toxoplasmosis (n = 4), viral infections (n = 9), mycobacterial infections (n = 5), localized bacterial (n = 12) and fungal infections (n = 4), malignancies (n = 3), and in various associated infectious and non-infectious febrile events (n = 13). All these plasma values were lower than 2.1 ng/ml. In contrast, high ProCT plasma levels were detected in one HIV-infected patient with a septicaemic Haemophilus influenzae infection (16.5 ng/ml) and another one with a septicaemic Pseudomonas aeruginosa infection (44.1 ng/ ml), ProCT values decreased rapidly under appropriate therapy. ProCT seems to be a specific marker of bacterial sepsis in HIV-infected patients, as no increase in other secondary infections could be detected in those patients. A rapid determination of ProCT level could be useful to confirm or refute bacterial sepsis for a better management of febrile HIV-infected patients.

Medical-legal considerations related to symptom duration and patient outcome after bacterial meningitis

Bacterial meningitis and viral encephalitis are infectious disease emergencies that can cause significant patient morbidity and mortality. Clinicians use epidemiologic, historical, and physical examination findings to identify patients at risk for these infections, and central nervous system (CNS) imaging and lumbar puncture (LP) may be needed to further evaluate for these diagnoses. The diagnosis of bacterial meningitis can be challenging, as patients often lack some of the characteristic findings of this disease with presentations that overlap with more common disorders seen in the emergency department. This article addresses considerations in clinical evaluation, need for CNS imaging before LP, interpretation of cerebrospinal fluid results, standards for and effects of timely antibiotic administration, and recommendations for specific antimicrobial therapy and corticosteroids.

Treatment of Vancomycin-Resistant Enterococcus faecium Infections

To define the clinical characteristics of patients infected with vancomycin-resistant enterococci (VRE) and the outcome of the infections without the availability of effective antimicrobial therapy. Charts of 28 patients with VRE infections were reviewed for demographics, clinical findings at the time of isolation of VRE, underlying medical problems, surgical procedures, invasive devices, treatment with antimicrobial agents, microbiological data, and patients' responses and outcomes. The infections included 6 cases of bacteremia, 9 surgical site infections (SSIs), 4 cases of peritonitis, 2 pelvic abscesses, 7 urinary tract infections (UTIs), and 2 soft tissue infections (STIs). Four of the 6 bacteremia cases were central-line related and resolved with line removal alone; 1 was treated with a combination product of quinupristin and dalfopristin (Synercid) and 1 had persistent bacteremia in the presence of a ventriculoperitoneal shunt. Seven of 9 SSIs resolved with surgical debridement and 2 of the 9 patients received antibiotics for organisms other than VRE. Similarly, 2 patients with STIs were treated with local debridement and antibiotics directed at organisms other than VRE and 2 patients with pelvic abscesses were treated with drainage and surgical debridement with antibiotics directed at other organisms; the infections resolved completely. Patients with peritonitis were treated with removal of their Tenckhoff catheters, drainage, and irrigation and 1 patient was treated with quinupristin-dalfopristin; 3 of 4 patients were cured. Two of 7 patients with UTIs were treated with nitrofurantoin and their urine cultures showed no growth after treatment; however, most patients with UTIs experienced resolution despite a lack of specific antimicrobial therapy. Although no antimicrobial agents are currently available for VRE infections, VRE line-related bacteremias could be treated by line removal alone. Surgical site infections, STIs, and abscesses could be managed by surgical debridement and drainage without specific antimicrobial agents against VRE and UTIs could be resolved with nitrofurantoin or removal of Foley catheters. Removal of foreign devices, debridement, and surgical drainage seemed to be important in the resolution of VRE infections.