Emergence of vancomycin resistance in Staphylococcus aureus. Glycopeptide-Intermediate Staphylococcus aureus Working Group.

BACKGROUND: Since the emergence of methicillin-resistant Staphylococcus aureus, the glycopeptide vancomycin has been the only uniformly effective treatment for staphylococcal infections. In 1997, two infections due to S. aureus with reduced susceptibility to vancomycin were identified in the United States. METHODS: We investigated the two patients with infections due to S. aureus with intermediate resistance to glycopeptides, as defined by a minimal inhibitory concentration of vancomycin of 8 to 16 microg per milliliter. To assess the carriage and transmission of these strains of S. aureus, we cultured samples from the patients and their contacts and evaluated the isolates. RESULTS: The first patient was a 59-year-old man in Michigan with diabetes mellitus and chronic renal failure. Peritonitis due to S. aureus with intermediate resistance to glycopeptides developed after 18 weeks of vancomycin treatment for recurrent methicillin-resistant S. aureus peritonitis associated with dialysis. The removal of the peritoneal catheter plus treatment with rifampin and trimethoprim-sulfamethoxazole eradicated the infection. The second patient was a 66-year-old man with diabetes in New Jersey. A bloodstream infection due to S. aureus with intermediate resistance to glycopeptides developed after 18 weeks of vancomycin treatment for recurrent methicillin-resistant S. aureus bacteremia. This infection was eradicated with vancomycin, gentamicin, and rifampin. Both patients died. The glycopeptide-intermediate S. aureus isolates differed by two bands on pulsed-field gel electrophoresis. On electron microscopy, the isolates from the infected patients had thicker extracellular matrixes than control methicillin-resistant S. aureus isolates. No carriage was documented among 177 contacts of the two patients. CONCLUSIONS: The emergence of S. aureus with intermediate resistance to glycopeptides emphasizes the importance of the prudent use of antibiotics, the laboratory capacity to identify resistant strains, and the use of infection-control precautions to prevent transmission.

A cluster of pseudofungemia associated with hospital renovation adjacent to the microbiology laboratory.

OBJECTIVE: To determine the clinical significance and source of fungemia following a cluster of positive blood cultures during a 3-day period. DESIGN: Chart review was used to determine the clinical significance of positive blood cultures. Microbiologic sampling of the laboratory environment was used to determine potential sources of fungal contamination. SETTING: A large, tertiary care, community teaching hospital. PATIENTS: All patients with blood cultures positive for Aspergillus species, Penicillium species, or both during the outbreak period. RESULTS: Thirteen patients, all children, were reported to have positive blood cultures for fungus during a 3-day period in early 1990. None had clinical features consistent with fungemia. Investigation of specimen processing procedures revealed that microbiologic plates were not processed--as per protocol--under the biologic hood but inadvertently were left open to air on the work bench by laboratory technicians. Settling plates left at the workbench, at door entry sites, and at sites of renovation immediately adjacent to the laboratory were positive for Aspergillus and/or Penicillium; control plates placed elsewhere were negative. Airflow patterns suggested spread into the microbiologic laboratory through an open door located near the implicated workbench station and a false ceiling above the workbench area. CONCLUSIONS: Our investigation demonstrates that faulty technique in the laboratory coupled with a change in environmental conditions can result in false-positive cultures and an outbreak of pseudofungemia.

Complications associated with central venous catheters inserted in critically ill neonates.

OBJECTIVE: To assess the incidence and spectrum of complications associated with central venous catheter (CVC) placement in the critically ill infant. DESIGN: A prospective study of all babies hospitalized in a neonatal intensive care unit (NICU) from January 1989 to December 1989. Potential risk factors associated with infection were evaluated by a case-control comparison. SETTING: Conducted at a university-affiliated, tertiary care community hospital. PATIENTS: Neonates requiring intensive care and a central venous catheter. Controls consisted of noninfected babies. RESULTS: Of 263 critically ill neonates, only 13 (4.9%) required a CVC insertion. Seventeen CVCs were placed in these 13 neonates for a total duration of 600 days (median, 32 days/cannula). Fifteen (88%) of these cannulas had one or more complications during its catheter life including dislodgement or leakage (53%), occlusion or thrombosis (47%), infections (29%), or minor bleeding (12%). Five babies (29%) developed 6 episodes of bloodstream infection including 3 sporadic cases due to Staphylococcus epidermidis and a cluster of fungemia due to Malassezia furfur associated with lipid emulsion therapy. Infants with a CVC-associated infection were a younger gestational age (24 weeks versus 32 weeks, p = .04) and weighed less at birth (580 g versus 1285 g, p = .02). The overall rate of bloodstream infection was one episode per 100 days of catheter use. CONCLUSIONS: CVCs may be lifesaving to a critically ill neonate, but complications occur frequently. Use must be restricted to infants in whom alternate delivery routes of intravenous therapy or support are otherwise unavailable.

Person-to-person transmission of Brucella melitensis.

Human brucellosis is primarily an occupational hazard in the USA; in the Middle East and Africa ingestion of contaminated dairy products is an important route of infection. Whether human beings can become infected via person-to-person spread is uncertain. During an investigation of a commonsource, laboratory-associated outbreak due to Brucella melitensis, biotype 3, the wife of a microbiologist with serologically proven brucellosis became infected. Her blood isolate was indistinguishable from the epidemic strain. In the absence of other risk factors, we suggest that sexual intercourse is a possible means of transmission.

The clinical spectrum of endophthalmitis: incidence, predisposing factors, and features influencing outcome.

Endophthalmitis is a virulent ocular inflammation typically developing suddenly and progressing rapidly. To better understand the incidence and factors predisposing to infection and influencing outcome, records of 114 patients with endophthalmitis hospitalized at one institution from 1980 to 1986 were reviewed. An infectious origin was confirmed in 79 patients (69%). The most common pathogens included staphylococcal species (Staphylococcus epidermidis, 33 cases; Staphylococcus aureus, 8 cases), streptococci (18 cases), gram-negative organisms (10 cases), and fungi (7 cases). Predisposing factors for infective endophthalmitis included preceding ocular surgery (67%), penetrating trauma (13%), systemic infection (11%), and periocular infection (5%). Despite vitrectomies and aggressive use of antibiotics, 42 patients (53%) with infective endophthalmitis suffered major visual loss. Morbidity was less pronounced with infection caused by S. epidermidis (23%; P less than .05). Patients with infective endophthalmitis more likely required repeated vitrectomies, were hospitalized longer, and had a worse outcome (as measured by complete enucleation) than those with "sterile" endophthalmitis. On the basis of these data, empiric vancomycingentamicin might be initiated in patients with endophthalmitis. Studies to define optimal management are needed, because the morbidity associated with this entity remains pessimistically high despite state-of-the-art treatment.

Infections caused by Moraxella, Moraxella urethralis, Moraxella-like groups M-5 and M-6, and Kingella kingae in the United States, 1953-1980.

From 1953 to 1980 the Centers for Disease Control received 933 isolates of bacteria belonging to species of the genus Moraxella, Moraxella-like Moraxella urethralis, now renamed Oligella urethralis, unnamed groups M-5 and M-6, and Kingella kingae. Ordinarily sterile sites were the source of 233 isolates. Moraxella nonliquefaciens, the most common isolate (356 strains), was recovered from upper respiratory or ocular sites in 208 (58%) of the cases. Moraxella osloensis was next most common (199 strains) but was the most frequent blood isolate (44 cases). K. kingae appeared especially invasive, with 58 of 78 isolates from blood, bone, or joint. Of the K. kingae strains, 75% were recovered from children under 6 years, compared with 23% of the other strains from that age group (P less than .01). Of the 74 isolates of group M-5, 53 were from wounds caused by dog bites; no other organism in this series was recovered from such wounds. Sixteen of the 28 M. urethralis isolates were from urine. Cases occurred as single infections, with no evidence of clusters. Of patients with infection of ordinarily sterile sites, 9.3% died; only bacteremia, meningitis, and empyema caused fatalities. Most referring laboratories (98%) had not identified the organisms to species, and only 30% had identified them to correct genus. Susceptibility testing by broth dilution revealed low MICs of penicillin (mean, 0.3; 64% less than 1 micrograms/mL). Moraxella, M. urethralis, M-5, M-6, and Kingella are important but frequently misidentified pathogens for humans; penicillin appears to be the treatment of choice.

Disseminated cryptococcosis presenting as cellulitis with necrotizing vasculitis.

Patients with disseminated cryptococcosis infrequently present with cutaneous involvement. Skin lesions, when present, are usually multiple and polymorphous in appearance. Cellulitis caused by Cryptococcus neoformans is rare, and necrotizing vasculitis associated with cryptococcal vascular invasion has not to our knowledge been reported. We report here a case of disseminated cryptococcosis in a renal transplant recipient who had cellulitis and necrotizing vasculitis and in whom a diagnostic skin biopsy allowed for early therapy with cure and salvage of the renal allograft.

Bacteremias due to Citrobacter diversus and Citrobacter freundii. Incidence, risk factors, and clinical outcome.

From 1974 to 1982, 38 patients developed Citrobacter bacteremia at two adult community-teaching hospitals in the Detroit Medical Center (incidence, 1.2 cases per 10,000 discharges). Citrobacter accounted for 0.7% of all bacteremias during the study period. Of 31 cases reviewed, Citrobacter bacteremia frequently developed in elderly patients (65%) and was hospital acquired (77%). Initial sites of infection included the urinary tract (39%), gastrointestinal tract (27%), wound (10%), and unknown (13%). More bacteremias caused by Citrobacter diversus tended to arise from the urinary tract, while patients with Citrobacter freundii bacteremia had significantly more gallbladder disease. Patients with Citrobacter bacteremia were more likely than patients with Escherichia coli bacteremia to have had additional pathogens in the bloodstream, to develop bacteremia in the hospital, and to have undergone invasive procedures contributing to infection. Significant differences were not observed in demographic, host, or other epidemiologic or clinical factors examined. Of patients with Citrobacter bacteremia, 48% died.

Bacterial meningitis in the United States, 1978 through 1981. The National Bacterial Meningitis Surveillance Study.

From 1977 to 1981, 18,642 cases of bacterial meningitis were reported to the Centers for Disease Control. We analyzed data from 27 states with full participation from 1978 through 1981. Hemophilus influenzae was the most frequent cause of bacterial meningitis (48.3%), followed by Neisseria meningitidis (19.6%) and Streptococcus pneumoniae (13.3%). Overall attack rates for males were greater than for females (3.3 v 2.6 cases per 10(5) population per year). Attack rates were highest in children under 1 year of age (76.7 per 10(5) population per year). Case-fatality ratios were highest for gram-negative and miscellaneous causes of bacterial meningitis (33.7%) and lowest for meningitis caused by H influenzae (6.0%). Neisseria meningitidis and S pneumonia meningitis occurred preponderantly during the winter, while H influenzae meningitis had peak activity in the spring and fall. Ampicillin resistance among H influenzae increased from 18.7% in 1978, to 23.9% in 1981. Serogroup B Neisseria meningitidis was the most common serogroup identified during the reporting period (51.1%), followed by serogroup C (22.3%), serogroup Y (5.8%), and serogroup A (4.7%) infections.

Prevention of Hemophilus influenzae type b disease.

To determine the efficacy of rifampin prophylaxis in eradication of oropharyngeal carriage of Hemophilus influenzae type b and prevention of secondary H influenzae type b disease, we conducted a multicenter placebo-controlled trial among selected persons with invasive H influenzae type b disease. Households and day-care classrooms were randomized so that their members received either rifampin (initially at a dose of 10 mg/kg/dose for two to four days [rifampin-10], but subsequently at 20 mg/kg/dose for four days [rifampin-20]) or placebo. Pretherapy H influenzae type b colonization rates were similar in the treatment groups. Therapy with either rifampin regimen significantly reduced carriage (rifampin-20, 97%; rifampin-10, 63%; placebo, 28%). New acquisition of carriage was also significantly reduced by either rifampin regimen (rifampin-20 or rifampin-10, 2% v placebo, 6%). No rifampin-resistant H influenzae type b isolates emerged after treatment. Four of 765 placebo-treated contacts experienced secondary disease in contrast to zero of 1,112 rifampin-treated contacts. Because chemoprophylaxis of close contacts with rifampin seems to reduce significantly the risk of secondary H influenzae type b disease, we recommend the administration of prophylaxis in households or day-care classrooms where children younger than 4 years have been exposed to the disease.

Recommendations for the care of automated peritoneal dialysis machines: can the risk of peritonitis be reduced?

Automated peritoneal dialysis systems have helped make intermittent peritoneal dialysis an alternative to hemodialysis for long-term management of patients with end-stage renal disease. However, if not cleaned and maintained properly, these machines provide a reservoir for pathogens. The microbiologic barriers in these machines are not impenetrable, but sterile dialysate fluid can be produced if the machines are adequately cleaned and disinfected. Potential shortcomings of the microbiologic barriers are discussed, and guidelines to prevent contamination of the internal parts of a machine are suggested.

Trimethoprim and rifampin in combination for chemoprophylaxis of household contacts of patients with invasive infections due to Haemophilus influenzae type b.

We compared the effectiveness of rifampin-trimethoprim in fixed combination (3.75:1) to rifampin alone in the eradication of Haemophilus influenzae type b carriage among contacts of patients with invasive infection caused by this organism. The study population was composed of 127 index patients and 620 contacts. Twenty-six percent of contacts were colonized. Rifampin-trimethoprim eradicated carriage in 77.6% of contacts (71.1% in contacts less than 5 years, 84.2% in contacts greater than or equal to 5 years) whereas rifampin eradicated carriage in 69.9% of contacts (56.4% in contacts less than 5 years, 81.8% in contacts greater than or equal to 5 years). A single isolate resistant to rifampin and rifampin-trimethoprim was encountered. The eradication rate achieved with this regimen of rifampin-trimethoprim was too low to recommend its routine use. However, a higher dose or longer course might merit clinical trial.

Recurrent urban histoplasmosis, Indianapolis, Indiana, 1980-1981.

In January 1981, informal surveillance of acute histoplasmosis in Indianapolis, Indiana, revealed a marked increase in disease activity for the last quarter of 1980. Fifty-one patients with onset of acute histoplasmosis during this period were identified through review of hospital admissions, emergency room visits, and serologic records at Indianapolis hospitals and the Indiana State Board of Health. In a retrospective case-control study, the authors found a significant association between developing acute histoplasmosis during this period and working or attending classes in a 2 sq mi (5.2 sq km) area encompassing the Indiana University-Purdue University campus (p = 0.015, Fisher's exact test). A review of construction activities on or near the campus during the epidemic period suggested that the probable source of infection was excavation activity for a large new indoor swimming complex (natatorium). Skin tests and serosurveys of students on campus by a newly developed radioimmunoassay for histoplasmal immunoglobulin M antibodies supported the association of infection with exposure to this site (p less than 0.05).

Pseudomonas aeruginosa serotype 0:9. New cause of whirlpool-associated dermatitis.

In a five-day period, dermatitis developed in nearly one fourth of the guests staying at a large Georgia hotel. Dermatitis was associated with use of the hotel's whirlpool (p less than 0.001) and indoor swimming pool (p less than 0.001). Attack rates were highest among persons more frequently exposed to the whirlpool, in persons under 10 years of age, and during periods of heaviest bather load. Pseudomonas aeruginosa was isolated from skin lesions of 13 of 20 patients from whom culture specimens were taken. Ten isolates were serotype 0:9. The whirlpool's water grew P. aeruginosa serotype 0:9; however, the whirlpool's automatic chlorinator was functioning properly, the pH of the water was 7.2, and the free chlorine level was 0.6 mg/liter. This is the first report of a whirlpool-associated outbreak caused by P. aeruginosa serotype 0:9. Our findings suggest that this strain may not be readily sensitive to recommended chlorine concentrations.

Pseudomonas folliculitis: an outbreak and review.

In November 1980, an outbreak of folliculitis due to Pseudomonas aeruginosa occurred in members of a health spa in Tennessee. The source of infection was traced to the health spa swimming pool, which had not been chlorinated for two days due to equipment malfunction. Thirty-seven (62%) of 60 members who used the swimming pool on these two days developed a papulopustular rash within eight hours to five days after swimming in the pool. The rash had a characteristic distribution, predominantly involving the buttocks, hips, and axillae. Other manifestations of infection included otitis externa (49%) and mastitis (11%). P. aeruginosa serogroup 0-11 was isolated from pustules of six people. A swab from the edge of the swimming pool also grew P. aeruginosa serogroup 0-11. With the rising popularity of home whirlpools and hot tubs, physicians may expect to encounter this disease with increasing frequency.

Risk factors for development of toxic shock syndrome. Association with a tampon brand.

In September 1980, we interviewed by telephone 50 patients with menstrually associated toxic shock syndrome (TSS) who had onset of illness in July or August 1980. These women were asked to provide information about the type of menstrual sanitary products used during the menstrual period associated with their illness. We also interviewed 150 age-matched control subjects, who were asked the same questions for the menstrual period that occurred in the same month as the illness of the matched case. All 50 cases, but only 125 of 150 controls, used tampons. Among women using tampons, cases were more likely to have used Rely brand tampons when compared with controls. No differences were found between cases and controls in the absorbency of tampon products used. No other factors studied through analysis of a follow-up questionnaire mailed five months after the first study were found to be significantly associated with the development of menstrually associated TSS.

Resistance of Mycobacterium chelonei-like organisms to formaldehyde.

Mycobacterium chelonei-like organisms have been isolated from patients in two outbreaks of peritonitis involving chronic peritoneal dialysis machines routinely disinfected with 2 to 3% formaldehyde. Susceptibility studies revealed that water-adapted M. chelonei-like organism strains could survive 2 h of exposure to 10% formaldehyde.