Appropriateness of empiric gentamicin and vancomycin therapy for bacteremias in chronic dialysis outpatient units in the era of antibiotic resistance.

Bacteremias in inpatient chronic HD units have been described, but there is little information on bacteremias in ambulatory HD units. To determine the frequency of bacteremia and pathogen distribution in ambulatory chronic HD units, we retrospectively reviewed our experience with 107 bacteremias in 5 chronic ambulatory HD units over a 3 year period. The object of the study was twofold. The first objective was to determine if bacteremias in ambulatory HD setting were substantially different in frequency or type than in the inpatient HD setting. Secondly, febrile patients suspected of having bacteremia in chronic HD patients are often empirically treated with vancomycin and gentamicin. Chronic HD patients require repeated and frequent venous access for HD. Bacteremias are common in chronic HD patients and may be primary or secondary and are often related to venous access site infections. The distributions of bacteremia pathogens in chronic HD patients are predominantly reflective of skin flora, i.e., staphylococci and to lesser extent aerobic Gram-negative bacilli. After S. aureus (MSRA/MSSA) and coagulase-negative staphylococcus (CoNS), enterococci are the next most important Gram-positive pathogens in bacteremic HD patients. Most strains of E. faecalis are sensitive to vancomycin and for practical purposes should be considered as vancomycin sensitive enterococci (VSE). In contrast, most strains of E. faecium are resistant to vancomycin and should be considered as vancomycin resistant enterococci (VRE). We retrospectively reviewed 107 patients on chronic ambulatory HD to determine the adequacy of empiric vancomycin and gentamicin prophylaxis. We found amikacin is preferred to gentamicin and that meropenem is an effective alternate substitution for gentamicin and vancomycin combination therapy.

Trimethoprim-sulfamethoxazole versus pentamidine for Pneumocystis carinii pneumonia in AIDS patients: results of a large prospective randomized treatment trial.

OBJECTIVE: To compare the clinical efficacy and safety of trimethoprim-sulfamethoxazole (TMP-SMX) with pentamidine in the therapy of Pneumocystis carinii pneumonia (PCP) in patients with AIDS. PATIENTS, PARTICIPANTS: TMP-SMX (TMP, 20 mg/kg/day plus SMX, 100 mg/kg/day) was compared with pentamidine (4 mg/kg/day), both administered intravenously for 21 days in a prospective randomized treatment trial of 163 patients diagnosed with PCP between November 1984 and May 1988. RESULTS: Ninety-two evaluable patients received TMP-SMX as initial therapy; 68 received pentamidine. Failure to complete therapy was common. Of those receiving TMP-SMX, 39 (42%) required change in therapy because of failure to respond, and an additional 31 (34%) because of drug toxicity. This compared with 27 (40%; P = 0.733) and 17 (25%; P = 0.235), respectively, in the pentamidine-treated group. The overall survival rates were similar in the two groups, 62 out of 92 (67%) initially administered TMP-SMX versus 50 out of 68 (74%) initially administered pentamidine (P = 0.402). The survival rates for patients requiring a change in therapy because of failure to respond was 46% (18 out of 39) for the TMP-SMX group compared with 56% (15 out of 27) for the pentamidine group. When a change in therapy was made because of toxicity, survival rates were 97% (30 out of 31) for those receiving TMP-SMX versus 94% (16 out of 17) for those receiving pentamidine. CONCLUSION: TMP-SMX and pentamidine are of equivalent efficacy as initial therapies for PCP in patients with AIDS.

Mycobacterial meningitis. Retrospective analysis from 1970 to 1983.

The clinical presentation and course of tuberculous meningitis in 21 patients treated between 1970 and 1983 are analyzed. Tuberculous meningitis may present as acute, subacute, or chronic meningitis. Although characteristic cerebrospinal fluid findings of lymphocytic pleocytosis, low glucose level, and elevated protein level occur in the majority of cases, there are many atypical presentations. The protein level, glucose level, and white blood cell count may be normal, and there may be a predominance of polymorphonuclear cells rather than lymphocytes in the cerebrospinal fluid. Poor prognostic factors in this series were age greater than 65, underlying diseases, and stage 3 presentation. Incorrect or inadequate therapy had a disastrous outcome. Nontuberculous mycobacteria rarely are involved in central nervous system disease. Tuberculous meningitis must be considered in the differential diagnosis of any patient with fever and change in sensorium. A deteriorating mental status and falling cerebrospinal fluid glucose level in the presence of negative findings on bacterial culture and india ink preparation should lead to strong consideration for empiric initiation of anti-tuberculous therapy.

Use of mycobacterial smears in the diagnosis of pulmonary tuberculosis in AIDS/ARC patients.

Pulmonary tuberculosis in AIDS/ARC patients is an increasing problem. To assess the utility of acid-fast smears of pulmonary secretions in this patient population, we evaluated 38 AIDS/ARC patients with culture-positive pulmonary infection. A control group consisted of 57 non-AIDS/ARC patients, who also did not belong to an AIDS risk group, diagnosed during the same period. The number of culture-positive sputum samples evaluated per patient was similar in both groups (3.82 +/- 3.11 AIDS/ARC vs 4.47 +/- 2.83 control group). Significantly fewer AIDS/ARC patients, 45 percent, however, had a positive acid-fast smear compared with the control group, 81 percent (p less than 0.001). The initial sputum smear submitted was positive in only 29 percent of the AIDS/ARC group compared with 61 percent of control subjects (p less than 0.01). Further, greater than or equal to 5 negative smears were found in 60 percent of the evaluable AIDS/ARC patients compared with just 13 percent of control subjects (p less than 0.01). More extensive findings on chest roentgenograms were not associated with a significantly higher yield of smear positivity in the AIDS/ARC group. We conclude that acid-fast smears on sputum specimens are a relatively insensitive test for pulmonary tuberculosis in AIDS/ARC patients.

Treatment of fever.

Fever is an important indicator of disease and should not be routinely suppressed by antipyretics. There is considerable evidence that fever may actually benefit the host defense mechanism. In most patients, fever is short-lived and causes only minor discomfort. Antipyretic agents are effective in lowering temperature, but have significant side effects. Routine antipyretic therapy should be avoided but may be necessary in individual patients with underlying cardiovascular or neurologic disorders.

Infections associated with steroid use.

Patients receiving chronic steroids have an increased susceptibility to many different types of infections. The risk of infection is related to the dose of steroid and the duration of therapy. Although pyogenic bacteria are the most common pathogens, chronic steroid use increases the risk of infection with intracellular pathogens such as Listeria, many fungi, the herpes viruses, and certain parasites. Clinicians should consider both common and unusual opportunistic infections in patients receiving chronic steroids.

Cytomegalovirus and legionella species as the cause of liver enzyme elevations in haemodialysis patients.

We conclude that reinfection or recurrent infection with CMV or legionella may be responsible for serum glutamic-pyruvic transaminase (SGPT) elevations in up to one fourth of haemodialysis patients. Since NANB infection or asymptomatic coinfection with these agents cannot be discounted with certainty, it seems prudent to maintain haemodialysis patients with abnormal liver-function tests on Body Fluid Precautions, even if they remain asymptomatic.

New uses of older antibiotics.

Despite the development of extended-spectrum penicillins, cephalosporins, and quinolones, the older antimicrobial agents, doxycycline, minocycline, TMP-SMX, clindamycin, and metronidazole, still play an important role in the treatment of infectious diseases. All of these older drugs are well absorbed by the oral route, attaining serum levels equivalent to those achieved by parenteral administration. The availability of generic forms of the older drugs reduces their cost. Besides traditional uses, some older drugs have become the preferred therapy for newly recognized infectious diseases. Doxycycline is the preferred drug for rickettsial tickborne diseases, ehrlichiosis and early Lyme disease. TMP-SMX is the preferred drug for I. belli and Cyclospora. Minocycline has been used to treat MRSA and MRSE infections. Clindamycin or metronidazole combined with a quinolone is an excellent oral regimen for polymicrobial infections. [table: see text]

Third-generation cephalosporins.

Third-generation cephalosporins are broad-spectrum antimicrobial agents useful in a variety of clinical situations. No one cephalosporin is appropriate for all infectious disease problems. Cefotaxime and ceftizoxime have the best gram-positive coverage of the third-generation agents. Ceftazidime and cefoperazone are the only third-generation drugs that provide antipseudomonal coverage. Ceftriaxone's long half-life allows for once-daily dosing, making ceftriaxone an excellent drug for outpatient antibiotic therapy of community-acquired infections. Ceftriaxone is also useful for the treatment of Lyme disease and sexually transmitted diseases. The third-generation cephalosporins except for cefoperazone penetrate cerebrospinal fluid and are indicated for the treatment of bacterial meningitis. Their proven record of clinical efficacy, favorable pharmacokinetics, and low frequency of adverse effects make third-generation cephalosporins the preferred antibiotic in many clinical situations.

Tetracyclines.

Tetracyclines are relatively safe drugs with a broad antimicrobial spectrum. Doxycycline remains the preferred tetracycline agent for most indications. Doxycycline has a long half-life, which makes convenient twice-a-day dosing possible. It is well absorbed orally even in the presence of food, has excellent tissue penetration, and does not require a dose adjustment in renal insufficiency. Doxycycline is a useful agent for the treatment of atypical pneumonias, sexually transmitted diseases, traveler's diarrhea, rickettsial infections, and Lyme disease. Minocycline is the preferred drug for MRSA colonization/infection.

The psychologist as admitting clinician. A single case example.

An experiential view of significant issues associated with independent hospital practice for psychologists is offered through a case presentation. The example is a model of practice in effect at a 90-bed, free-standing, inpatient facility opened in 1985, that gives psychologists full professional staff privileges.

Brain abscess mimicking brain tumor.

We review our experience with brain abscesses presenting as primary brain tumor over a 5-year period (1983 to 1988). Four of 66 (6%) patients admitted with the diagnosis of primary brain tumor by computed tomographic scans were found at craniotomy to have brain abscesses. Periapical abscesses found after surgery were determined to be the cause of brain abscess in two of four patients. Our experience suggests that periapical abscess may be a more frequent cause of brain abscess than previously thought, and should be considered before surgery in patients with a suspected brain tumor.

Postoperative Serratia marcescens endophthalmitis.

Endophthalmitis after ophthalmic surgery is a rare but serious complication. Postoperative endophthalmitis presents clinically with conjunctival erythema and lid edema with eye pain and decrease in visual acuity. Diagnosis requires invasive culture techniques because postoperative external eye cultures are not reflective of intraocular organisms. The most common pathogens causing postoperative endophthalmitis are staphylococci and streptococci. Less common organisms associated with exogenous endophthalmitis include gram-negative aerobic bacilli and fungi. We report a case of Serratia marcescens postoperative endophthalmitis in a normal host.

Poststernotomy mediastinitis.

The clinician should suspect mediastinitis in patients after sternotomy who have unexplained fever or leukocytosis, sternal wound tenderness, or atypical chest or neck discomfort 2 to 3 weeks following surgery. Mediastinitis should be considered if any of these features are present. The diagnosis should be aggressively pursued by mediastinal aspiration via the suprasternal notch. Early empiric treatment with an antibiotic(s) with antistaphylococcal and gram-negative coverage is critical to survival.

Listeria monocytogenes meningitis in a human immunodeficiency virus-positive patient undergoing hemodialysis.

Listeria monocytogenes bacteremia without meningitis has been reported in patients who have undergone long-term hemodialysis and have transfusional iron overload. On the other hand, cases of Listeria bacteremia without meningitis have occurred sporadically among the acquired immunodeficiency syndrome population, mostly homosexuals. There have been no reports of Listeria meningitis occurring among persons who are antibody positive to human immunodeficiency virus or are intravenous drug abusers having chronic renal failure and undergoing hemodialysis. This patient represents the first case of Listeria bacteremia and meningitis to occur in an intravenous drug abuser who is human immunodeficient antibody positive, is receiving hemodialysis, and has transfusional iron overload.

Early seizures in patients with acquired immunodeficiency syndrome without mass lesions.

Generalized tonic-clonic seizures in persons infected with the human immunodeficiency virus have usually occurred in the setting of space-occupying lesions in the brain. Seizures have also been known to occur in patients with acquired immunodeficiency syndrome-related dementia. Two patients, each with prior history of human immunodeficiency virus infection, had seizures early in the course of their illness. Neither patient had evidence of space-occupying lesions or dementia at the time of admission for the seizures. Patients with human immunodeficiency virus infection may present with seizures and may not have a clinically detectable focus for their seizures.

Klebsiella pneumoniae pneumonia.

Klebsiella pneumoniae is an uncommon cause of community-acquired pneumonia except in alcoholics. Klebsiella may mimic pulmonary reactivation tuberculosis because it presents with hemoptysis and cavitating lesions. Klebsiella pneumoniae is a difficult infection to treat because of the organism's thick capsule. Klebsiella is best treated with third- and fourth-generation cephalosporins, quinolones, or carbapenems. Monotherapy is just as effective as a combination treatment in Klebsiella pneumoniae because newer agents are used. In the past, older agents with less anti-Klebsiella activity were needed for effective treatment. The patient we present was initially thought to have pulmonary tuberculosis, and when found to have Klebsiella pneumoniae, the suggested treatment was monotherapy with ceftriaxone. The patient was treated parenterally initially, and then was treated for 3 weeks with oral ofloxacin.

The selection and use of cephalosporins: a review.

Cephalosporins are among the most frequently prescribed antibiotics as a result of their broad spectrum of microbiologic activity, favorable pharmacokinetics, low incidence of adverse reactions, and proven clinical efficacy for a wide variety of infections. Cephalosporins differ in their gram-positive, gram-negative, and anaerobic spectra, serum half-lives, penetration of the cerebrospinal fluid, and resistance to beta-lactamases. The first-generation and some second-generation agents maintain excellent activity against streptococci and staphylococci, while the third-generation agents have expanded gram-negative coverage. Two third-generation cephalosporins, ceftazidime and cefoperazone, are active against Pseudomonas. Ceftizoxime has become the workhorse third-generation cephalosporin. The fourth-generation agent cefepime provides excellent activity against gram-positive and gram-negative pathogens, including antibiotic-resistant Enterobacteriaceae. A major dilemma facing the practitioner is how to select the "right" cephalosporin for a particular patient, as no one drug will satisfy all clinical needs. This review describes a practical approach to selecting an appropriate cephalosporin for common infectious disease problems.