Charles V. Sanders

Infections related to the ingestion of seafood Part I: viral and bacterial infections

Foodborne diseases cause an estimated 76 million illnesses in the USA each year. Seafood is implicated in 10-19% of these illnesses. A causative agent can be traced in about 44% of seafood-related outbreaks, viruses accounting for around half of these illnesses. Although viruses are the most common cause of seafood-related infections, most hospitalisations and deaths are due to bacterial agents. A wide variety of viruses, bacteria, and parasites have been implicated in seafood-related outbreaks, which are reported worldwide. The factor most commonly associated with infection is consumption of raw or undercooked seafood. People with underlying disorders, particularly liver disease, are more susceptible to infection. The first part of this two-part review summarises the general incidence of seafood-related infections and discusses the common viral and bacterial causes of these infections. For each agent, the microbiology, epidemiology, mode of transmission, and treatment are discussed. In the May issue of the journal we will discuss parasites associated with seafood consumption, the safety of seafood, and the measures put in place in the USA to increase its safety.

Serratia marcescens infections from inhalation therapy medications: nosocomial outbreak.

Abstract An outbreak of nosocomial infections caused by non-pigmentedSerratia marcescensis described. There were 655 bacterial isolates from 374 patients during a 10-month period; 50.4% of isolates...

Activities of ciprofloxacin and ofloxacin against rapidly growing mycobacteria with demonstration of acquired resistance following single-drug therapy.

The susceptibility to ciprofloxacin of 548 clinical isolates of rapidly growing mycobacteria belonging to eight subgroups or species was determined. The 170 isolates of Mycobacterium fortuitum biovar.fortuitum were most susceptible; the MIC for 90% of the organisms was 0.125 micrograms/ml. The other biovariants of M. fortuitum, M. smegmatis, and the M. chelonae-like organisms were less susceptible; the modal MIC was 0.5 micrograms/ml, and the MIC for 90% of organisms was 1.0 micrograms/ml. The two subspecies of M. chelonae were generally resistant, with only 8% of 206 isolates falling in the moderately susceptible category (MIC, 2 micrograms/ml) and only 2% falling in the susceptible category (MIC, less than or equal to 1 micrograms/ml). MICs of ofloxacin averaged 1 to 2 dilutions higher than those of ciprofloxacin for all subgroups tested. Three patients with M. fortuitum cutaneous disease relapsed after an initial response to therapy with ciprofloxacin, and their isolate was shown to have acquired drug resistance. Mutational frequencies for M. fortuitum with ciprofloxacin were relatively high (10(-5) to 10(-7), and MICs for single-step mutants were similar to those for the clinically resistant strains. Thus, despite the excellent activity of ciprofloxacin against rapidly growing mycobacterial groups other than M. chelonae, single-drug therapy should be used with caution because of the risk of development of mutational resistance.

Unusual manifestations of invasive pneumococcal infection

Unusual pneumococcal infections occurred frequently in the preantibiotic age but rapidly declined with the advent of the antibiotic era. Unfortunately, the morbidity and mortality associated with invasive pneumococcal disease remain high despite antibiotic therapy and monumental advances in medical technology. The incidence of invasive pneumococcal disease has increased recently because of the onset of the human immunodeficiency virus (HIV) epidemic and the emergence of antibiotic-resistant pneumococcus. Robert Austrian described the clinical triad of pneumococcal pneumonia, meningitis, and endocarditis, a syndrome that now bears his name. Although seen infrequently today, unusual manifestations of pneumococcal infection such as those Austrian reported still occur. A review of these cases is warranted because, as drug-resistant organisms continue to emerge worldwide, more unusual pneumococcal infections will be seen. Streptococcus pneumoniae is responsible for a remarkable array of disease processes; our literature review uncovered 95 different types of unusual pneumococcal infections representing 2,064 cases. Examples of these infections included pancreatic and liver abscesses, aortitis, gingival lesions, phlegmonous gastritis, inguinal adenitis, testicular and tubo-ovarian abscesses, and necrotizing fasciitis. We also reviewed predisposing underlying illnesses and conditions. Alcoholism, HIV infection, splenectomy, connective tissue disease, steroid use, diabetes mellitus, and intravenous drug use remain common risk factors for invasive pneumococcal infections. Currently, multidrug-resistant S. pneumoniae remains susceptible to vancomycin and several new third-generation fluoroquinolones. As what some fear will be a possible postantibiotic era approaches, clinicians must be able to recognize and manage unusual pneumococcal infections.

Myonecrosis Caused by Edwardsiella tarda: A Case Report and Case Series of Extraintestinal E. tarda Infections

Edwardsiella tarda is an unusual human pathogen. It is primarily associated with gastrointestinal disease, although recent reports of extraintestinal disease are broadening the current understanding of the clinical spectrum of E. tarda. A series of 11 cases of extraintestinal E. tarda infection is presented, including the first reported case of myonecrosis in an immunocompetent patient. Wound infections were the most common manifestation, and 3 of 5 patients with infected wounds had been exposed to a marine environment. One patient had bacteremia, and the remaining 5 patients developed abscesses that required surgical drainage. Four patients had E. tarda isolated in pure culture, including the patient with myonecrosis. Although it is often difficult to ascertain the contribution of E. tarda to infection when it is isolated as part of a mixed culture, this case series suggests that E. tarda is singularly capable of causing limb- and life-threatening infections.

Bacteremia due to Bacteroides fragilis group: distribution of species, beta-lactamase production, and antimicrobial susceptibility patterns.

ABSTRACT A retrospective analysis of susceptibility data on 542 blood isolates of the Bacteroides fragilis group tested from 1987 to 1999 by the same NCCLS-recommended broth microdilution method throughout is presented. Metronidazole, β-lactam-β-lactamase inhibitor combinations, carbapenems, and trovafloxacin were the most active agents (susceptibility of ≥93%). Among the cephalosporin-cephamycins, the order of activity was cefoxitin > ceftizoxime > cefotetan = cefotaxime = cefmetazole > ceftriaxone. All isolates were resistant to penicillin G, and 22% were resistant to clindamycin. The susceptibility rates to piperacillin-tazobactam, imipenem, and meropenem were affected least among isolates resistant to cefoxitin or clindamycin. Except for piperacillin-tazobactam, imipenem, and meropenem, the B. fragilis species was more susceptible than were the non-B. fragilis species. These data underscore the importance of susceptibility testing of the B. fragilis group and can serve as a guide in the choice of empirical antimicrobial therapy.

Comparison of the activities of penicillin G and new beta-lactam antibiotics against clinical isolates of Bacteroides species.

MICs were determined for 218 clinical isolates of Bacteroides by a broth microdilution method. Imipenem was the most active antibiotic tested. Azlocillin, mezlocillin, and cefoxitin had comparable activities, with resistance among members of the B. fragilis group and B. capillosus. Ceftizoxime was the most active cephalosporin tested. Members of the B. fragilis group showed high levels of resistance to cefotetan and ceftazidime. Resistance to penicillin G varied from 0 to 14%.

Vibrio vulnificus infection: Case report and update since 1970

Vibrio vulnificus infections is being reported with increasing frequency in coastal regions of the United States. Raw seafood consumption, particularly raw oysters, and wounds acquired in a marine environment predispose to infection. Patients with advanced liver disease are at increased risk of developing septicemia. V. vulnificus is a virulent pathogen producing significant morbidity and mortality; its virulence relates in part to the production of exotoxin. Skin lesions occur early in the clinical course of infection and provide means of specific diagnosis. The patient and the consulting physician are well served by the dermatologist capable of recognizing this infectious disease.

Candidal Suppurative Peripheral Thrombophlebitis

Transient candidemia is common with prolonged intravenous therapy. Sustained candidemia, however, usually indicates a persistent focus of infection. A complication of intravenous therapy not previously emphasized is persistent candidemia caused by candidal suppurative peripheral thrombophlebitis. We report six cases that appeared during intravenous therapy: the infection was characterized by a thrombosed peripheral vein at an intravenous site with manifestations for candida septicemia with or without disseminated candidiasis. In two patients, the source of the process was occult; the examination showed only a thrombosed noninflamed vein. In all cases, surgical exploration showed the thrombosed veins to be suppurative with positive cultures for Candida. Special stains, moreover, showed Candida in the luminal clot and the vascular wall. In the five surviving patients, cure was achieved by excision of the affected vein. Four received a short course of amphotericin B and 5-fluorocytosine, and one patient received amphotericin B only.

Single-dose cefaclor therapy of urinary tract infection: Evaluation of antibody-coated bacteria test and C-reactive protein assay as predictors of cure

The efficacy of single-dose (cefaclor, 2 g orally) and multidose (cefaclor, 250 mg orally three times a day for 10 days) antibiotic regimens in the therapy of acute uncomplicated urinary tract infections (UTI) in nonpregnant women were compared. The patients clinical status and results of urine cultures were compared in retrospect with the results of the antibody-coated bacteria (ACB) test and C-reactive protein (CRP) test in order to determine if either test would predict the patients response. Overall, 10 of 30 patients (33 percent) and 18 of 22 patients (81 percent) given single doses and multidoses, respectively, had negative urine cultures four weeks after completion of therapy. A negative urine culture at four weeks correlated with a negative ACB test utilizing the less inclusive criteria for negativity (less than 5 bacteria with fluorescence in 5 minutes of search) but not with a negative ACB test utilizing the more inclusive criteria (less than 10 percent bacteria with fluorescence) or with a negative CRP test. The cure rate in the ACB-negative single-dose group (7 of 9 patients) utilizing the less inclusive criteria for negativity was similar to the cure rate in the ACB-negative multidose group (8 of 10 patients). This study suggests that the ACB test, if properly standardized, might permit identification of a population of patients with UTI who would respond to single-dose cefaclor therapy.