Yersinia enterocolitica septicemia with septic arthritis.

We report a case of Yersinia enterocolitica septicemia with septic arthritis. Gentamicin administration controlled the septicemia but failed to eradicate the organisms in the joint, in spite of a synovial fluid level four times its minimal inhibitory concentration after four days of therapy. Development of azotemia necessitated change of antibiotic therapy to chloramphenicol, which eradicated the infection. While Y enterocolitica infection in the United States is uncommon, it must be added to the list of organisms causing suppurative arthritis and septicemia in susceptible hosts. Septic arthritis must be distinguished from the much more common reactive theumatic polyarthritis associated with Y enterocolimica infection, for which antibiotic therapy is neither needed nor helpful.

Acute meningococcal pericarditis without meningitis.

Meningococcla pericarditis without evidence of meningitis of pericardial effusion in an 18-year-old man was cured following a ten-day course of orally administered ampicillin. Acute pericarditis resembling benign or viral pericarditis amy rarely be due to N meningitidis.

Antibiotic-resistant flora in nursing home patients admitted to the hospital.

To study carriage of multiply resistant gram-negative bacilli, 50 patients admitted to the hospital from nursing homes (NHs) and 50 control admissions not from NHs were matched for age and recent antibiotic use. Their antibiotic resistance patterns were similar: 20 NH patients and 14 controls had resistant strains. However, significantly more patients (64%) from NHs with large numbers of "skilled beds" had resistant bacteria than did patients from small NHs (21%) or controls (28%). Also, more patients from NHs had members of the Proteus-Providencia-Morganella group in their urine than did controls. Discriminant analysis showed that residence in NHs with large numbers of skilled beds, recent antibiotic use, and bladder dysfunction (indwelling catheter or incontinence) were independently important in predicting carriage of resistant strains in NH and control patients. Over 75% of resistant isolates were from rectal specimens, emphasizing the occult way that such strains are brought into the hospital.

Strategies for prevention and control of multiple drug-resistant nosocomial infection.

Multiple drug-resistant bacteria are common in the hospital and are often isolated from patients on admission. Spread in hospital and occasional epidemics result from transient contamination of the personnel's hands, environmental contamination and excessive use of antibiotics. Traditional control measures have relied on improved asepsis and handwashing, isolation (or cohorting) of infected and colonized patients, antibiotic control and elimination of any significant environmental sources. Newer approaches have focused on ways of preventing (or eliminating) patient carriage of multiple drug-resistant strains. We have tailored selected barrier-type "antibiotic resistance precautions" for everyday use to control endemic aminoglycoside resistant gram-negative bacilli. We detail our multifaceted approach and suggest its ongoing use for key multiple drug-resistant strains, in "epi-centers," such as intensive care units, for potential heavy shedders of multiple drug-resistant strains, and when certain epidemic thresholds are reached.

Pyogenic sacroiliitis.

Seven definite and three probable cases of pyogenic sacroiliitis are presented and compared to 72 cases found in the English literature. Patients may present with a subacute localized or an acute systemic illness. Six of our patients were parenteral drug abusers. Symptoms often were vague, but sacroiliac tenderness was invariably found on examination. Sacroiliac uptake of gallium67 citrate and/or technetium99m pyrophosphate suggested the diagnosis which was confirmed by fluoroscopically controlled joint aspiration when blood cultures were sterile. Gram-negative organisms, group B streptococci and a Staphylococcus were isolated. Antibiotic treatment for four to six weeks was uniformly successful. Surgery should be reserved for abscess or sequestrum formation, neither of which were encountered in this series.

False localization of site of endocarditis by cardiac catheterization with quantitative cultures.

The authors present a patient with relapsing Pseudomonas aeruginosa endocarditis in whom cardiac catheterization with quantitative cultures falsely localized the infection to the tricuspid valve, probably because the patient was having intermittent rather than continuous bacteremia. After catheterization the patient developed mitral insufficiency and congestive heart failure. This experience suggests that quantitative cultures during cardiac catheterization may give misleading results and that the procedure may have significant complications.

Pseudomonas in the sinks in an intensive care unit: relation to patients.

Sink drains in a medical-surgical intensive care unit (ICU) were cultured during six consecutive weeks as part of a seven month prospective study of acquisition of Pseudomonas aeruginosa by ICU patients. Isolates were typed serologically and by aminoglycoside and chlorhexidine susceptibility patterns. All 11 sinks contained multiple strains of P aeruginosa; some strains persisted for weeks while others were isolated once. Of the sink isolates 56% had high level resistance to gentamicin and tobramycin whereas none of the strains found in patients. In sink isolates chlorhexidine resistance correlated with aminoglycoside resistance and with the presence of a chlorhexidine dispenser at a sink. The sequence of recovery of phenotypically similar isolates suggested that sinks were the source of at most two acquisitions of P aeruginosa by patients during the six weeks. Our study confirms that sinks may be reservoirs for large numbers of highly resistant P aeruginosa but are rarely the source of organisms colonising patients in our ICU.

Infections with gram-negative bacilli in a cardiac surgery intensive care unit: the relative role of enterobacter.

A 7-month prospective survey for cefazolin-resistant Gram-negative bacilli in cardiac surgery patients, receiving cefazolin prophylaxis, showed that 58 (67%) of 87 were colonized with enterobacter, 37 (64%) with citrobacter, 33 (57%) with Pseudomonas aeruginosa, and seven (2%) with Serratia marcescens. About 50% of colonization occurred before cefazolin prophylaxis and was present on admission to the intensive care unit. Typing of strains showed that horizontal transmission accounted for at most 14% of carriage. Cefazolin prophylaxis (and high gastric pH) were associated with increased levels of postoperative colonization, most notably for enterobacter. About 25% of colonization with enterobacter, pseudomonas, and serratia was followed by clinical infection. Enterobacter cloacae was the most common pathogen and pneumonia the most common infection. Infections contributed to eight of 11 deaths; four of the eight involved enterobacter. Potential control measures include eliminating endogenous Gram-negative flora by gut decontamination or at least stemming the increase in level of colonization that occurred after surgery.

In vitro activity of 5-episisomicin in bacteria resistant to other aminoglycoside antibiotics.

Eighty-seven isolates of Pseudomonas, Enterobacteriaceae, and Staphylococcus, chosen because of their resistance to other aminoglycosides, were tested for susceptibility to 5-episisomicin. Tests were performed in Mueller-Hinton agar and also, with 38 of these isolates, in Mueller-Hinton broth. Of Enterobacteriaceae, 85 and 95.5% were inhibited by 5 and 10 mug of 5-episisomicin per ml, respectively. Amikacin inhibited 74 and 91% of the strains at 10 and 20 mug/ml, respectively. Fifty-four percent of P. aeruginosa were inhibited by 5-episisomicin and amikacin. Eighty-three percent of S. aureus were inhibited by netilmicin and amikacin, whereas only 50% were inhibited by 5-episisomicin. Isolates resistant to 5-episisomicin were most often resistant to the other aminoglycosides and occurred in gram-negative bacilli that did not carry aminoglycoside-modifying enzymes. Five of 23 isolates that carried a 6'-N-acetyltransferase (AAC-6') and one of two that carried an aminoglycoside 3-acetyltransferase were resistant to and acetylate 5-episisomicin. Strains carrying other aminoglycoside-modifying enzymes were inhibited by 5-episisomicin. Thus, 5-episisomicin is a promising aminoglycoside not attacked by most aminoglycoside-modifying enzymes. Resistance will probably most often be based upon nonenzymatic mechanisms which will also affect other aminoglycosides.

Subacute staphylococcal meningitis secondary to postpartum endometritis.

A woman with Staphylococcus aureus meningitis following postpartum endometritis presented with lumbar backache and fever of several weeks' duration. Thick, green exudate was aspirated at lumbar puncture hours before death. Histologic examination demonstrated subacute inflammation of the meninges and chronic inflammation of the endometrium. Although rare, postpartum endometritis followed by low back pain and fever should alter the physician to the possibility of serious infection involving the central nervous system. Diagnosis and treatment at this early stage would be expected to decrease mortality.

Hemophilus influenzae f cellulitis with bacteremia, peritonitis, and pleuritis in an adult with nephrotic syndrome.

Hemophilus influenzae f was responsible for cellulitis with bacteremia, pleuritis, and peritonitis in an adult patient with the nephrotic syndrome. The patient rapidly responded to ampicillin. H influenzae f has previously been rarely found to cause pleuritis and bacteremia, but has not been reported as a cause of cellulitis or primary peritonitis. Patients with the nephrotic syndrome are prone to serious infection with encapsulated bacteria. The relative frequency of infection with the various encapsulated bacteria most likely parallels that of colonization by these organisms.

In vitro activity of Sch 21420, derivative of gentamicin B, compared to that of amikacin.

The minimal inhibitory concentration of Sch-21420 closely paralleled amikacin for 125 strains of aerobic gram-negative bacilli and Staphylococcus aureus primarily selected for testing because of resistance to other aminoglycoside antibiotics. Fifteen of 26 strains requiring 20 mug or more of amikacin per ml for inhibition were inhibited by two- to fourfold less Sch 21420. The majority of organisms resistant to both agents owed their resistance to mechanisms other than the carriage of aminoglycoside-modifying enzymes. Most strains carrying aminoglycoside 6'-acetyltransferase, capable of modifying amikacin, were susceptible to 10 mug or less of Sch 21420 per ml.

In vitro comparison of netilmicin, a semisynthetic derivative of sisomicin, and four other aminoglycoside antibiotics.

One hundred isolates of Pseudomonas and Enterobacteriaceae, of which 85 were chosen because of their resistance to gentamicin or amikacin, were tested for susceptibility to netilmicin (SCH 20569), a new semisynthetic derivative of sisomicin, and to four other aminoglycosides. Tests were performed in Mueller-Hinton agar and, with 43 of these isolates, also in Mueller-Hinton broth. Most isolates of Escherichia coli, Klebsiella, Enterobacter, Citrobacter, and Serratia that were gentamicin resistant proved to be susceptible to netilmicin and amikacin. Tests of representative isolates of this group showed that they owed their resistance to the production of aminoglycoside-adenylylating enzymes. Four isolates of Serratia, detected by their resistance to amikacin, were also highly resistant to netilmicin but were susceptible to gentamicin. These isolates produced aminoglycoside-acetylating enzymes. Gentamicin-resistant Proteus and Providencia were, in general, highly resistant to netilmicin but were susceptible to amikacin. These isolates also produced aminoglycoside-acetylating enzymes. Most gentamicin-resistant strains of Pseudomonas were resistant to netilmicin, either by enzymatic aminoglycoside modification or by other undefined mechanisms. Thus, like amikacin, netilmicin extends the aminoglycoside susceptibility pattern of Enterobacteriaceae to include gentamicin-resistant isolates that produce aminoglycoside-adenylylating enzymes. It is ineffective against strains, some of them susceptible to amikacin, gentamicin, or tobramycin, that produce aminoglycoside-acetylating enzymes.

Infections due to gentamicin-resistant Staphylococcus aureus strain in a nursery for neonatal infants.

An apparently homogeneous strain of Staphylococcus aureus resistant to gentamicin (Gmr), kanamycin, tobramycin, and sisomicin, but susceptible to amikacin and netilmicin, caused multiple infections in neonatal infants in a special care nursery. Nasal cultures revealed a high rate of carriage of the Gmr staphylococcus in infants without clinical infection. Segregating patients according to a modified cohort system and use of careful aseptic techniques led to apparent elimination of the Gmr strain. The resistance to aminoglycosides in this strain was mediated by an aminoglycoside 6'-N-acetyltransferase and a gentamicin phosphotransferase. Genetic determinants for these enzymes were borne on a circular covalently closed plasmid of approximately 11 megadaltons. These resistance determinants closely resemble those found in isolates of S. aureus that have caused nosocomial infections in patients in Europe.

Endemic aminoglycoside resistance in gram-negative bacilli: epidemiology and mechanisms.

Isolates of gentamicin-resistant gram-negative bacilli from clinical specimens peaked at nine to 10 per month in 1973-1974. Instituting barrier-type precautions during 1974-1977 was associated with a sustained 87% reduction in resistant Enterobacteriaceae. The number of resistant Pseudomonadaceae fell temporarily by 28%, paralleling gentamicin usage. During an endemic 15-month period in 1976-1977 nonenzymatically mediated resistant Pseudomonas aeruginosa often emerged after aminoglycoside therapy in patients who had prior carriage of sensitive strains of the same serotype (P = 0.002); this resistance was associated with wound or sputum isolates (P = 0.003). Resistant Enterobacteriaceae more often demonstrated the converse, that is, spread of urinary tract isolates with enzymatically mediated resistance from patients not on aminoglycoside therapy. These findings suggest that control measures to minimize occurrence of resistant bacilli include barrier-type precautions for patients with resistant Enterobacteriaceae, evaluation of transfers and readmissions as a source of resistant organisms, and reduction of aminoglycoside use to decrease the selection of nonenzymatic resistance.

Pilot trial of selective decontamination for prevention of bacterial infection in an intensive care unit.

Selective decontamination of the oropharynx and gastrointestinal tract with nonabsorbable antimicrobials and sucralfate, a stress ulcer prophylactic that maintains the normal gastric acid bacterial barrier, were compared for prevention of pneumonia in a cardiac surgery intensive care unit. Over 8 months, 51 patients received selective decontamination and 56 received sucralfate. The selective decontamination regimen included polymyxin, gentamicin, and nystatin given as an oral paste and as a solution; patients also received standard antacid or histamine2 blocker stress ulcer prophylaxis. Patients in the selective decontamination group had significantly less colonization of the oropharynx and stomach by gram-negative bacilli (12% vs. 55%, P less than .001), significantly fewer infections due to gram-negative bacilli (6% vs. 20%, P = .02), and fewer infections overall (12% vs. 27%, P = .04). There was one episode of pneumonia in the selective decontamination group and five in the sucralfate group. Mortality and length of stay did not differ between the groups, but those receiving selective decontamination had less than one-third as many days of systemic antibiotic therapy with no increase in colonization or infection with resistant gram-negative bacilli. Thus, selective decontamination appeared to reduce both extrapulmonary and pulmonary infections.

Occult aminoglycoside resistance in Pseudomonas aeruginosa: epidemiology and implications for therapy and control.

The epidemiology of aminoglycoside-resistant Pseudomonas aeruginosa was evaluated in an intensive care unit (ICU) with serial surveillance cultures of throat and rectum. Bacterial population analysis performed by replica plating of primary isolation plates onto gentamicin-containing agar revealed the presence of resistant subpopulations in the initial isolates from 41 (71%) of 58 consecutive assessable patients; these isolates were stably resistant and proportionately less susceptible to other aminoglycosides. An increase in resistant subpopulations occurred during the ICU stay in 34% of 38 colonized patients cultured serially as opposed to none of 23 followed after ICU discharge (P = .0008). Isolates of P. aeruginosa from patients who received aminoglycosides in the ICU were more likely to show an increase in resistance than were isolates from other patients (55% vs. 11%; P = .005); decreasing resistance after ICU discharge followed discontinuation of antibiotic administration. ICU mortality was higher in patients with increasingly resistant subpopulations (69% vs. 16%; P = .0004). The difficulty in treating infections with P. aeruginosa and in controlling drug resistance likely relates to the common carriage of clinically undetected resistant subpopulations that emerge during therapy.