Biomedical subjects
Publications and source records attributed to D Shamsuddin.
A 62-year-old man presented with haemoptysis and radiographic features compatible with pulmonary tuberculosis. His course was complicated by severe haemoptysis that required surgical lobectomy. Mycobacterium xenopi was cultured from sputum and lung tissue. The post-operative course was complicated by gastro-intestinal haemorrhage and the patient died.
To study the natural course of catheter-induced endocarditis secondarily infected with Staphylococcus epidermidis, 29 rabbits had catheters introduced surgically through the carotid artery to the aortic valve. Forty-eight hours later the catheters were removed from five rabbits. The rabbits were inoculated intravenously with 10(8) colony-forming units of S epidermidis. Autopsies done at various intervals showed all rabbits with indwelling catheters had noticeable aortic valve vegetations with positive cultures for S epidermidis. In the group with catheters removed after 48 hours, less severe valvular lesions were noted. Metastatic seeding to kidneys, spleen, and liver were noted in both groups. Because of low cure rate in the treatment of S epidermidis endocarditis, this rabbit model could be used to study antibiotic regimens for valvular endocarditis.
Antibiotic susceptibility and synergy were studied in 12 clinical isolates of Listeria monocytogenes from patients with meningitis and septicemia. Rifampin and trimethoprim-sulfamethoxazole (TMP-SMX) were the most potent single drugs tested. Approximately 80% of the strains demonstrated full synergistic bactericidal activity with rifampin in combination with penicillin or ampicillin. Clinical experience dictates that ampicillin or penicillin should remain the antibiotic of choice in the treatment of severe infections, such as meningitis caused by L. monocytogenes. Where the use of penicillin is contraindicated (e.g., allergy or failure to respond), use of TMP-SMX might be considered. Further in vitro and vivo studies are needed before therapy with rifampin or TMP-SMX in combination with penicillin or ampicillin can be recommended.
Cefoxitin sodium, a new cephamycin antibiotic, is active against many aerobic and anaerobic bacteria. Four patients with infections of the head and neck (otitis externa with cellulitis, parotiditis, tracheitis, and facial cellulitis), who had failed to respond to initial antibiotic regimens, responded satisfactorily to cefoxitin therapy. No adverse effects were noted in any of these patients. Results of this report suggest cefoxitin is a safe and well-tolerated antibiotic that is efficacious in the treatment of head and neck bacterial infections that are sensitive to this drug.
Street heroin and injection paraphernalia have been implicated as sources of bacteria causing infections in drug abusers [1]. Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus cereus are common etiologic agents. In a previous study of the microbiology of street heroin and injection paraphernalia, Bacillus species was the predominant isolate [2]. We did not find S. aureus, but one study reported isolates of identical phage type from heroin powder and from an infected patient [3]. To reconcile the results of our recent investigation among drug abusers with panophthalmitis, we theorized that the drug mixture might have an antibacterial effect. Of the samples of street heroin tested, all except one were bactericidal against S. aureus. The single sample with no heroin content was not bactericidal against one isolate of S. aureus and was the only sample that exhibited some degree of inhibitory and bactericidal activity against P. aeruginosa. All samples were bactericidal against the two isolates of B. cereus tested. Quinine exhibited bactericidal activity against S. aureus and B. cereus but was ineffective against P. aeruginosa. Our findings indicate that most samples of street heroin have antibacterial effects against S. aureus and B. cereus but no activity against P. aeruginosa. Such activity may be due to the quinine content of the mixture. The apparent lack of recovery of S. aureus from street heroin may be partially explained by this phenomenon.
Serious infections with the "nonpathogenic" Bacillus species are increasingly being recognized, especially in drug abusers. Cases of panophthalmitis secondary to infection with Bacillus cereus, with and without associated bacteremia, have been reported. Three drug abusers with panophthalmitis seen in our hospitals during a three-year period are described, and the similar cases reported in the literature are reviewed. The syndrome is characterized by an acute onset with a rapid fulminating course that eventually leads to enucleation or evisceration of the eye. The pathogenic mechanism is unknown, but is probably related to the production of toxin (lecithinase) by B. cereus. Clindamycin appears to be the antibiotic of choice in the treatment of this infection. In order to identify a possible source of the organism, 59 samples of heroin and injection paraphernalia were cultured. Twenty cultures yielded organisms; Bacillus species were the predominant isolates. Thirty-eight percent of the isolates were identified as B. cereus. Thus, infections caused by Bacillus species in drug abusers can probably be associated with intravenous heroin abuse because heroin mixtures and injection paraphernalia are frequently contaminated with this organism.