Streptococcal infection in a regional burns centre and a plastic surgery unit

Outbreak of infections caused by Group A Streptococcus after modified radical mastectomy

BACKGROUND

Eight infections occurred after modified radical mastectomies in a tertiary-care hospital. Group A streptococci (GAS) were isolated from three of the eight patients.

METHODS

To control the outbreak, an epidemiologic investigation was conducted, and healthcare workers were screened for pathogens. Strains isolated from healthcare workers were compared with patient strains by emm typing.

RESULTS

One surgeon attended one of the eight operations and observed the other seven. Streptococcus strains from the hands of this surgeon were identical to the patient strains. After the surgeon was suspended from duty and underwent eradication treatment, the outbreak was controlled.

CONCLUSIONS

This outbreak of GAS infection is believed to have occurred by airborne transmission. Suspending patient care by healthcare workers who carry the causative GAS in a site(s) other than the respiratory tract for only the first 24 h they are receiving chemoprophylaxis may not be long enough. Sampling of the hands of healthcare workers during an investigation of nosocomial GAS infection is valuable.

Hospital-acquired invasive group a streptococcal infections in Ontario, Canada, 1992-2000

BACKGROUND

A significant proportion of invasive group A streptococcal infections are hospital acquired. No large, prospective studies have characterized this subgroup of cases and evaluated the risk of transmission in hospitals.

METHODS

We conducted prospective, population-based surveillance of invasive group A streptococcal infections in Ontario, Canada, from 1992 to 2000. Epidemiologic and microbiologic investigations were conducted to identify cross-transmission.

RESULTS

We identified 291 hospital-acquired cases (12.4%) among 2351 cases of invasive group A streptococcal disease. Hospital-acquired invasive group A streptococcal infections are heterogeneous, including surgical site (96 cases), postpartum (86 cases), and nonsurgical, nonobstetrical infections (109 cases). Surgical site infections affected 1 of 100,000 surgical procedures and involved all organ systems. Postpartum infections occurred at a rate of 0.7 cases per 10,000 live births and exhibited an excellent prognosis. Nonsurgical, nonobstetrical infections encompassed a broad range of infectious syndromes (case-fatality rate, 37%). Nine percent of cases were associated with in-hospital transmission. Transmission occurred from 3 of 142 patients with community-acquired cases of necrotizing fasciitis requiring intensive care unit (ICU) admission, compared with 1 of 367 patients with community-acquired cases without necrotizing fasciitis admitted to the ICU and 1 of 1551 patients with other cases (P<.001). Fifteen outbreaks were identified; 9 (60%) involved only 2 cases. Hospital staff were infected in 1 of 15 outbreaks, but colonized staff were identified in 6 (60%) of 10 investigations in which staff were screened.

CONCLUSIONS

Presentation of hospital-associated invasive group A streptococcal infections is diverse. Cross-transmission is common; illness occurs in patients but rarely in staff. Isolation of new cases of necrotizing fasciitis and intervention after a single nosocomial case may also prevent transmission.

A Streptococcus pyogenes outbreak caused by an unusual serotype of low virulence: the value of typing techniques in outbreak investigations

OBJECTIVES

To investigate and stop the spread of an outbreak of Streptococcus pyogenes infection in a district general hospital, involving 19 patients and two nurses over a 20-day period.

METHODS

All suspected persons were investigated using conventional bacteriological techniques, followed by M, T and exotoxin gene-typing of the isolates in a national reference laboratory.

RESULTS

11 patients and both nurses were associated with the acute surgical ward on one floor of the hospital. They were infected with serotype M 9/T B3264, a strain with apparently low virulence, which has not been previously associated with outbreaks. Two other patients on the same floor each had different types and there were two clusters of another S. pyogenes serotype on other floors, each involving two patients. Two (unrelated) patients yielded other types of S. pyogenes. The patients were not seriously ill but had some delay in wound healing.

CONCLUSIONS

The value of typing the isolates of S. pyogenes in this outbreak was in defining which patients were involved. No added value could be ascribed to the exotoxin gene-typing results.

Beta-haemolytic Streptococcus infection in burns

Group A beta haemolytic Streptococcus has been one of the most serious infections in the burn patients resulting in severe cellulitis and sepsis. Penicillin has been used ever since its introduction as prophylaxis against these conditions. Penicillin prophylaxis was used in our burn unit as well without any serious evaluation until December 1992. This prospective study was therefore, undertaken to evaluate the incidence of beta haemolytic Streptococcus infection in burn patients, and its clinical outcome over a period of 5 years in the absence of prophylaxis with penicillin. 14 of the 1213 burn patients admitted to the Al-Babtain Centre for Plastic Surgery and Burns from January 1993 to December 1997 had either colonization or infection with Streptococcus spp. Their mean age was 15 years (range 1 month to 52 years) and the mean burn surface area was 20% (range 5 to 90%). Streptococci were isolated from burn wounds in 10 patients, throat in 3 and blood culture in 1. Group A Streptococcus was found in 5, group C in 3 and group D in 6 patients. In all patients except one the organisms were isolated > or =72 h post burn. The infections were successfully controlled by antibiotic and no detrimental effect was observed either on wound healing or skin graft take. There was no mortality amongst these 14 patients. The study showed that only 1.1% of the burn patients in our unit acquired Streptococcus of which only one third comprised of group A. This study thus demonstrates that the practice of penicillin prophylaxis during the first five post burn days may not be of any value and therefore, deserves discontinuation in units where the incidence of this organism is minuscule.

Beta-haemolytic streptococcal infections in burned patients

Colonization of burn wounds by beta-haemolytic streptococci can lead to the loss of autografts. The present study investigated the beta-haemolytic streptococcal infections in burned patients treated in the Burns Centre of the Emergency Medical Institute 'N. I. Pirogov'. Sofia during a 12-month period (March 1991-March 1992). As many as 117 beta-haemolytic streptococcal strains were isolated in 114 burned patients (52 children and 62 adults). The distribution of the streptococcal strains according to their serogroup was 64 strains (54.7 per cent) group A; 34 strains (29.1 per cent) group B; nine strains (7.7 per cent) group G; five strains (4.25 per cent) group C and five other strains (4.25 per cent) group F. Antibiotic sensitivity tests demonstrated the presence of some differences among the serogroups, especially between groups A and B. The sources of the streptococcal infections were found in 26 (29.2 per cent) of the patients. Epidemiological relationships were established between the strains from one source and the wound swab. For the successful treatment of beta-haemolytic streptococcal infections in burns it is essential to bear in mind the role of non-group A beta-haemolytic streptococci (45.3 per cent according to our study).

Streptococcus pyogenes outbreak in a long-term care facility

BACKGROUND

Although outbreaks involving Streptococcus pyogenes have been uncommon among the elderly population, recent reports suggest that this organism is an important nosocomial pathogen among institutionalized older patients and carries significant morbidity and mortality. An outbreak of S. pyogenes, type M12, T12, occurred in a large long-term care institution serving the ill and chronically disabled. The outbreak involved 14 residents of the intermediate care facility and lasted for 4 months.

METHODS

A prospective epidemiologic investigation was initiated at the onset of the outbreak. Pertinent clinical and demographic information regarding both residents and personnel was obtained by interview, review of medical and surveillance records, and examination of patients for lesions. Cultures were obtained within 24 hours of symptom onset from those with characteristic clinical symptoms. Unpaired convalescent sera were tested for group A streptococcal extracellular antigens by a rapid hemagglutination slide test. Control measures included active surveillance of residents and staff for suspicious clinical syndromes, transfer of high-risk patients, elimination of a common seating area, and improved handwashing and hygiene measures.

RESULTS

The attack rate was 7.5%, with 64.3% of these patients residing on one unit. S. pyogenes was isolated from eight residents, 5 residents had a characteristic syndrome and an elevated streptozyme hemagglutination titer of 400, and 1 resident died within hours of having cellulitis of the groin. Clinical syndromes included cellulitis, pharyngitis, bronchitis, pneumonia, and septicemia. Seven residents required acute care; two residents died within 3 weeks of the onset, yielding a case fatality rate of 14.3%.

CONCLUSIONS

The major means of transmission appeared to be direct contact between residents, although transmission from an infected staff member may have accounted for some cases. The hypothesis of long-term colonization was supported by the extended times between infections. The severity of illness and the apparent transmission through direct contact between residents warrants (1) early detection of infected lesions, (2) recognition of invasive illness, (3) prompt effective treatment, and (4) surveillance for S. pyogenes infections among residents and personnel.

An outbreak of group A streptococcal skin infection: control by source isolation and teicoplanin therapy

Streptococcus pyogenes is a potential cause of serious infections in plastic surgery and burns units. We report an outbreak of this organism in one such unit, which was successfully managed by closing the ward, and treating infected patients with a new antibiotic, teicoplanin.