Enterococcal pneumonia

Enterococcal Pneumonia Occurrence in Patients Receiving Broad-Spectrum Antibiotic Regimens and Enteral Feeding

STEVEN L. BERK, M.D. ABRAHAM VERGHESE, M.D. SHIRLEY A. HDLTSCLAW, MS. J. KELLY SMITH, M.D. JohnsonCity, Tennessee

Enterococcal pneumonla occurred as a superinfectionIn two patlentswhorecehWdkoadspecttum-WY.~pe#ents were receiving enteral hyperallmentatlonby Dobb-Hoff tube. The organlsmwas Isolated from transtracheal aspirate In pure cutture and gram-positive cocci were visible on gram-stained smear. Enterococcal pneumonia may occur in patients recelvlng cephalosporln-amlnoglycosldetherapy, and may be antlclpated as a consequence of third-generationcephalosporlntherapy. Enterococcus is a common cause of urinary tract infection [ 11, bacteremia [2], and endocarditis [3,4]. The organism has not been implicated as a lower respiratory tract pathogen except, perhaps, in the setting of aspiration of amniotic fluid in the neonate [2]. EnterocoCcal superinfection has recently been associated with the new third-generation cephalosporins. Yu [5] has repotted on four ca5es of enteroccccal urinary tract infection or bacteremia in patients who had been treated with moxalactam. In 198 1, we treated two patients who had enterococca I pneumonia. In both cases, patients were receiving a combination of cefamandole-aminoglycoside therapy when the pneumonia developed. Enterococci were isolated in pure growth by transtracheal aspiration. CASE REPORTS

Case 1. An 85-year-old white man was transferred to the Veterans Ad-

Fromthe QulllenDishnerCollege of Msdicine arKI Veterans Administration Medical Center, JohnsonCity, Tennessee.Requests for reprints shouldbe addressedto Dr. StevenL. Berk(11l), VeteransAdminibdraHon MedicalCenter.Johnson ths

City, Tennessee 37694. February 23, 1982.

Manuscript accepted

ministration Medical Center after left hemiplegla secondary to cerebral thrombosis developed. He had been receiving enteral hyperalimentation by DobbHoff tube. On admission he was febrile, with a temperature of 102’F. A right lower lobe infiltrate was documemed on chest x-ray. A transtracheal aspirate was performed, which showed many gram-negative coccobacilli ongramstain.ThepatientwastreatedwlthcefamafXW (2geveryfouhoW and tobramycin (80 mg every eight hours) with clinical improvement. Five days later the patient became febrile, with a temperature of 103OF;his white blood cell count was 18.8. Chest x-rays showed mid-lung field and left upper lobe consolidation. A repeat transtracheal aspiration showed many white blood cells and gmm-positivecocci.ErythmmycinwasaddedtotheanWotic regimen but the patient did not improve. Two days later the transtracheal aspirate was reported as growing 4+ enterococci. as confirmed by the organisms’ ability to grow and react in bile esculin medium, and in trypticase soy broth containing 8.5 percent sodium chloride. The organism produced gamma hemolysis and was resistant to penicillin. Treatment with ampicillin

January 1983 The American Jsurnd of Msdlohm volema 74

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ENTEROCOCCAL PNEUMONIA-BERK

ET AL.

(12 g/day) was begun, but the patient died on the following day. Legionella and viral titers were negative. Postmortem examination was not performed. Case 2. A H-year-old black man was admitted for hyponatremia and became febrile and comatose while hospitalized. The patient was treated empirically with cefamandole (1 g every four hours) and amikacin (500 mg every 12 hours). l-4 became afebrile and enteral hyperalimentation was begun. On the sixth day of antibiotic therapy, the patient again became febrile (1OlOF) and a left lower lobe infiltrate developed. Transtracheal aspirate showed many polymorphonuclear leukocytes and gram-positive cocci. Culture grew 4-F enterocoocus. Identification was determined by (1) production of gamma hemolysis, (2) growth in 6.5 percent sodium chloride and growth after heating for 30 minutes at 60°C, (3) positive reaction in bile esculin medium, (4) resistance to penicillin greater than 4 pg/ml minimal inhibitory concentration, and (5) identification by API 20 STM(Analytab Products, Inc., New York) as group D enterococcus-Streptococcus fecalis. Administration of cefamandole and amikacin was discontinued and treatment with ampicillin (1 g every six hours) was begun. The patient improvedclinically and the

infiltrate resolved.

COMMENTS

Two patients with clinical and x-ray evidence of pneumonia had enterococcus isolated in pure growth by transtracheal aspiration and visible on gram-stained smear. Both patients were being fed by Dobb-Hofftube and both were receiving cefamandole and an aminoglycoside when pneumonia developed. lt is possible that the duodenum of these patients became colonized with bowel flora, that enterococci were selected by antibiotic therapy, and that pneumonia was the result of aspiration. Enterococci are relatively resistant to third-generation cephalosporins [6] and to the combination of cephalosporin-aminoglycoside [ 71, so that superinfection with enterococci may be expected with these regimens. It will be important to document cases of enterococcal pneumonia during therapy with thirdgeneration cephalosporins and other broad-spectrum antibiotic regimens so that this disease can be better characterized. Enterococcal pneumonia will require specific therapy with ampicillin, vancomycin, or a penicillin-aminoglycoside regimen.

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