Urinary-tract infections: etiology, microbiology, pathophysiology, diagnosis and management.

The increased incidence of urinary-tract infections (UTI) may be due to prolonged human longevity, increased drug resistance of pathogens, poor resistance of the urothelium and the existence of bacterial L forms. About 95 percent of recurrent infections are re-infections. The most common uropathogen is Escherichia coli, and the most virulent is Pseudomonas. UTI may be manifested as: a) asymptomatic bacteriuria, b) acute uncomplicated infection, c) acute complicated infection, or d) recurrent infection. Recurrent infections usually are refractory to treatment, and are caused by a pathogen different from the original one. Upper-tract (kidney) infections are difficult to cure, whereas bladder infections respond favorably. Prostatitis also responds poorly because effective drug levels are difficult to attain in prostatic tissue. Results of the antibody-coated bacteria test (ACB) and the bladder-washout test are helpful in locating the site of infection. Detailed outlines concerning diagnosis, management, chemotherapy and prophylaxis provide data on various types of infection and the effects of specific antimicrobial agents and other drugs at different sites in the urinary tract. A current plan for short-course prophylaxis does not fulfill expectations.

Influenza: epidemiology, etiology, immunization and management.

Influenza, an acute contagious respiratory infection caused by orthomyxoviruses A, B, and C, occurs in local outbreaks, epidemics and pandemics. Differences in the morphology and antigen patterns for these viruses account for the differences in virulence and immunity. Influenza A is virulent, B is mild, and C is nonvirulent. Swine influenza virus may spread from swine to man (recycling of human A virus), causing epidemics and pandemics. The 1976-77 influenza vaccination program involved swine virus, and was associated with 321 cases of Guillain-Barré syndrome and a mortality of 5 percent. Subsequent yearly programs with other types of vaccine are described. Dosages vary according to the age of the vaccinee. Those who need vaccination include persons over 65 years of age, patients with heart/lung, liver/lung or metabolic diseases, severe anemia, or a compromised antigenic system. Side effects include local reaction, fever, an allergic reaction (due to egg protein), and the Guillain-Barré syndrome (only with swine virus vaccine). In general, influenza vaccine is safe and confers 60-85 percent protection. Since immunity lasts only about a year, annual vaccination with recently isolated virus vaccine is recommended. Amantadine seems effective therapeutically and prophylactically for clinical influenza A infection.

Relative efficacy of carbenicillin indanyl sodium and of trimethoprim/sulfamethoxazole in urinary-tract infections.

In a 10-day study, carbenicillin indanyl sodium cured urinary-tract infections in 22 of 30 patients (ages, 24-91). In 3 of the remaining patients the treatment was a failure; in 3 others the drug had to be discontinued because of diarrhea and vomiting; and in 2 instances it induced overgrowth of Candida albicans in the urine. Carbenicillin was lethal to Pseudomonas aeruginosa in all 9 cases, to Proteus mirabilis in all 6 cases, and to enterococcus in all 3 cases. A trimethoprim/sulfamethoxazole combination cured urinary-tract infections in 18 of 30 other patients (ages, 28-91), but failed in 3. In 3 patients it gave rise to a skin rash; in 2 to elevation of blood urea nitrogen and creatinine levels; in 1 to neutropenia; and in 1 to overgrowth of Candida albicans in the urine. Reinfection occurred in 2 patients. Carbenicillin indanyl sodium was more effective than the sulfonamide/trimethoprim combination.

Urologic sepsis/shock.

At Columbia-Presbyterian Medical Center during the six-year period 1968-1973, there were 1236 cases of sepsis from Gram-negative pathogens; 124 of these originated in the urinary tract. Of these 124 patients, 19 died-a mortality rate of 15.3 percent. There were 205 deaths among the 1236 patients with sepsis from Gramnegative organisms-a mortality rate of 16.6 percent. Previously, in the 1959-1964 and 1965-19067 periods, the mortality rates had been 56.3 percent and 19.6 percent respectively. The lowered mortality rate during 1968-1973 for urologic sepsis/shock was associated with improved management procedures: a) preventive measures such as postponement of urologic instrumentation and surgical intervention in patients infected with drug-resistant urea splitters, until the infection is under control, with emergency surgical patients being treated by susceptibility-tested drugs to control possible postoperative complications; b) early diagnosis and treatment of sepsis and immediate administration of bactericidal antibiotics parenterally; c) immediate restoration of fluid/electrolyte balance, with monitoring of renal and pulmonary functions and metabolic acidosis; and d) early administration of large pharmacologic doses of glucocorticoids, with monitoring of the microcirculation and use of beta-adrenergic isoproterenol.

The changing pattern of bacterial sepsis since the introduction of antibiotic therapy.

During the six-year period, 1968-1973, sepsis developed in 1 of every 80 patients admitted to the Presbyterian Hospital, New York. In 1 of 133 patients the sepsis was due to Gram-positive organisms, and in 1 of 188 patients to Gram-negative organisms. The mortality rate for Gram-positive cases was 4.4 percent, for Gram-negative cases 19.1 percent, and for urologic cases 15.3 percent (versus 56.25 percent in 1959-1964). Data are presented on the relative incidences of involved pathogens in 1740 cases of Gram-positive sepsis /78 deaths), and in 1236 cases of Gram-negative sepsis (205 deaths). The lowering of the sepsis mortality rate has been the result of preventative measures, early diagnosis, and vigorous treatment. Treatment includes the correction of acidosis and anoxia, early administration of bactericidal antibiotics, and restoration of the microcirculation by administration of corticosteroids, beta-adrenergic drugs, and appropriate diuretics.

Glucocorticoid therapy in sepsis/shock caused by gram-negative microorganisms.

A review of the literature reveals that glucocorticoids have: 1) a protective effect both in vitro and in vivo against bacterial endotoxins and exotoxins, and 2) a protective or therapeutic effect in sepsis/shock caused by Gram-negative microorganisms. At the Columbia Presbyterian Medical Center, the 1968-1973 mortality rate for general sepsis/shock due to Gram-negative organisms was 16.6 percent and for urologic sepsis/shock 15.3 percent. This low rate was the result of early diagnosis and early use of massive dosages of glucocorticoids (hydrocortisone, methylprednisolone, dexamethasone), beta-adrenergic isoproterenol, and bactericidal antibiotics (gentamicin, kanamycin, carbenicillin, cephalothin-cefazolin, ampicillin).