Sixty-two A. faecalis infection cases were sporadically reported in the medical literature before 1997 (Table 7) [28-43]. The most commonly reported cases involved bacteremia and meningitis, and most cases occurred in newborns and infants. Most cases were treated with sulfonamides. Besides, no adequate information was mentioned in the literature. The age of patients, infection sites, and antibiotic therapy of A. faecalis infection cases before 1997 are different from A. faecalis infection cases after 1997. We separated the literature review in two periods (before and after 1997). Inappropriate and inadequate infection control strategies may be the cause of A. faecalis meningitis and A. faecalis bacteremia in high-risk newborns and infants. In 1960, Doxiadis reported 33 cases of bacteremia in newborns, which was the largest cases series before 1997 [37]. A. faecalis was resistant to sulfonamides, and there were 20 deaths due to A. faecalis bacteremia.
Table 7: Alcaligenes faecalis infection cases
Year/diagnosis
|
Before 1997
|
1997 to 2019
|
Our cases
|
cystitis
SSTI
Pneumonia
APN
Bacteremia
Pleural empyema
Otitis media
Meningitis
Endocarditis
Ocular infection
Peritonitis
Infectious diarrhea
specific sites infection
Total
|
0
0
0
0
39
0
0
15
2
2
0
3
1
62
|
10
12
6
0
3
0
21
1
1
8
2
0
2
66
|
25
11*
8
7
3
2
2
0
0
0
1
0
2
61
|
*: including 9 cases of diabetic foot infection, 1 case of surgical wound infection and 1 case of burn wound infection.
To our knowledge, there were 66 sporadically reported cases of A. faecalis infection in the literature after 1997 [1,2,7-26]. Fillipe reported 20 cases of chronic otitis media in Angola [19]. The use of bird feces by residents as a traditional remedy to prevent ear discharge was related to these A. faecalis chronic otitis media cases. The other infections from A. faecalis, in order of occurrence, were skin and soft tissue infection (SSTI), UTI, endophthalmitis, and pneumonia. In our series, the most frequent cases were, in order, UTI, SSTI, and pneumonia. We did not find any cases of endophthalmitis. The cases reported in the literature after 1997 (excluding the 20 cases of chronic otitis media in Angola) and our cases indicate that the most frequent A. faecalis infection sites, in order, were the urinary tract, skin and soft tissue (diabetic foot ulcer accounts for 56.5% of skin and soft tissue infection), and lung.
Whether A. faecalis isolation in mixed culture is pathogen or contaminant
In Tena’s report, two out of five skin and soft tissue A. faecalis cases were mixed with other bacterial infections [17]. In Filipe’s series, all the twenty A. faecalis otitis media cases were mixed with other bacterial infections [19]. Kahveci reported a case of A. faecalis peritonitis and made the conclusion that it was very important to view A. faecalis as a pathogen rather than contaminant [15]. Junejo mentions that it is evident that any organism found in the culture should not be completely disregarded, rather labeled as contaminant [23]. In 2017, Laham reported a clinical samples study of A. faecalis strain isolated from 2 outpatients and 3 inpatients, including 4 wounds cultures and one urine culture [44]. The study conducted for 3 months period only. In 2013, Khajuria reported a total of 15 clinical isolates of A. faecalis specimens such as urine, pus, blood, and body fluids from January 2012 through December 2012 [45]. We believe many cases of A. faecalis infections cases exist, but have not been reported in the literature. Our series of A. faecalis infection cases were about 10 cases every year, which was only a very small part of the infectious diseases in our hospital. We agreed the opinion of Junejo and we thought the A. faecalis was the infectious pathogen rather than contaminant.
The trend of antibiotic sensitive rate of A. faecalis
In 1997, Bizet first reported that A. faecalis strains were resistant to amoxicillin, ticarcillin, and gentamicin [1]. Amoxicillin-clavulanic acid and cefotaxime provided a successful treatment outcome for patients with A. faecalis infection. In 2000, Pereira reported that a strain of A. faecalis resistant to expanded-spectrum beta-lactamase cephalosporins was isolated from the urine of an inpatient [2]. In 2005, Dubois described the isolation of A. faecalis with ESBL in a patient with a concurrent urinary tract infection [11]. In 2017 and 2018, 2 cases of XDR A. faecalis pneumonia were reported by Agarwal and Junejo [22,23]. In 2019, Hasan reported a 60-year-old female with pandrug-resistant A. faecalis bacteremia who was treated with double-dose tigecycline and had a successful treatment outcome [26]. A pandrug-resistant A. faecalis pathogen had been found.
In our hospital, In March 2015, the strain A. faecalis showed sensitivity only to imipenem and meropenem in a pneumonia patient. In May 2018, a strain of XDR A. faecalis susceptible only to tigecycline was isolated from a pneumonia patient. The A. faecalis strain changed into XDR A. faecalis, which was remarkably faster than in the literature. There were 4 cases with XDR A. faecalis infection in our series, including 2 cases of pneumonia and 2 cases of diabetic foot infection.
In view of individual antibiotics, ciprofloxacin revealed a very low susceptibility rate of A. faecalis from 2014 to 2019. Piperacillin/tazobactam was significant in decreasing the susceptibility rate of A. faecalis since 2016. Emerging resistant strains of A. faecalis to imipenem and meropenem was found since 2018. A high resistance rate of many antibiotics was found in 2019. The best sensitivity rate to A. faecalis was 66.7% for three antibiotics (imipenem, meropenem, and ceftazidime). Two antibiotics (ciprofloxacin and piperacillin/tazobactam) sensitivity rates to A. faecalis were less than 50%.
From our experience, we recommend that ciprofloxacin and piperacillin/tazobactam are not good choices for empiric therapy of A. faecalis infection. Instead, we choose an appropriate antibiotic for a susceptible A. faecalis infection patient according to the results of his or her antibiotics sensitivity test. If the A. faecalis organism is an ESBL strain, carbapenem is an appropriate antibiotic. If the A. faecalis is an XDR strain, only polymyxin B or tigecycline is effective.
Treatment failure of A. faecalis infection cases
Among our reported cases of A. faecalis infection, there were seven treatment failure cases, including two cases of pneumonia, two cases of cystitis complicated with sepsis, three cases of diabetic foot infection. The overall treatment failure rate was 11.5%. We studied twenty-four A. faecalis cases with reported treatment outcome in the literature after 1997. Among them, there were three treatment failure cases, including one peritonitis case, one pneumonia case, and one diabetic foot ulcer case. The overall treatment failure rate was 12.5% [14,17,22]. A. faecalis is a low virulence bacterium. With adequate intravenous antibiotic therapy, patients with A. faecalis infection will usually have a good treatment outcome.
Four cases were cured with non-covering antibiotics, including 2 cases of diabetic foot infection,1 case of pleural empyema, and 1 case of surgical wound infection. The four cases had received appropriate wound care, adequate abscess drainage, and surgical intervention may be crucial for curing of infections.
Limitations
Our clinical study of A. faecalis infection was a small case series and therefore can provide only minimal clinical experience. Additional case series reports of A. faecalis infection will add to the knowledge of how to treat A. faecalis infection.