Inadequate antibiotic therapy of genitourinary tract infections could be responsible for viral sexually transmitted diseases
Ann Ig 2013; 25: 553-555
di
Giuseppe Alessio Messano
TO THE EDITOR: I have read with great interest the paper authored by Nardis and colleagues entitled “Vaginal microbiota and viral sexually transmitted diseases” (1). The Authors reported that these infections are a global public health problem with an estimated number of 19 million incident cases each year. Improper lifestyle behaviour is certainly at the basis of such a high infection rate (2,3). In addition, the Authors stressed the concept that the disruption of vaginal commensal flora, mostly non-pathogenic lactobacilli, is essential to promote installation and infection by viral pathogens, including HIV and HPV (1). It is very important, however, to remember that although humans are continuously exposed to a large amount of environmental factors potentially affecting their microbial ecology, incorrect antibiotic administration is probably the main promoter of such a disruption. For example, antibiotic therapy and consequent disruption of residential vaginal flora in a sample of healthy women, was responsible for a 16% incidence rate of vulvovaginal candidiasis, another frequent – although not viral- genitourinary tract infection (4). In a recent study on 128 strains of Mycoplasma hominis collected from genitourinary tract samples of adult males, we found that almost 90% of them were resistant to erythromycin and azithromycin and 50% to ofloxacin and ciprofloxacin (5). These data suggest two important aspects. First, if the majority of these strains were multi-resistant to antibiotics, they must have been previously subjected to several improper antibiotic therapies, which promoted their antibiotic resistance. Therefore, the sources of infections - mostly females with vaginal infection in our study - must necessarily undergo frequent (and improper) antibiotic therapy. Second, treatment of these micoplasmoses necessarily required the use of heavy and alternative antibiotic therapies which probably caused the disruption of the residential microflora of the genitourinary tract. In conclusion, I suggest that the interesting paper of Nardis and colleagues could be completed by considering the problem of frequent and improper antibiotic therapy for genitourinary tract infections. Indeed, since most lactobacilli are susceptible to beta-lactams and macrolides (6), this is the basis of the imbalance of the bacterial homeostasis in the human vagina.
Giuseppe Alessio Messano
Department of Public Health and Infectious Diseases, Section of Hygiene, Sapienza University, Rome, Italy
Antibiotic Effects on Vaginal MicrobiotaIN RESPONSE:The letter of G.A. Messano (1) requires some considerations.
The gold standard of antibiotic therapy should involve the use of an antibiotic only after the ascertainment of the nature of the bacterial infection and the identification of the most appropriate antibiotic for treatment. Unfortunately, in primary care, patients are often treated empirically without preceding culture or susceptibility testing. Due to the increasing prevalence of antibiotic resistant bacteria, particularly the extended spectrum beta-lactamase producing gram-negative bacteria, it is crucial to avoid antibiotic overprescribing. To reduce the selection of resistant bacteria, empiric prescribing of broad-spectrum antibiotics should be avoided in patients with trivial and uncomplicated infections, such as uncomplicated urinary tract infection. Furthermore, critically important antibiotics, such as fluoroquinolones, should be restricted to the most severe infections and always be preceded by a susceptibility test. Moreover, antibiotics where resistance rates of the most frequent uropathogens exceed 10 -20% should be avoided due to an increased risk of treatment failure and complications (2). An emerging issue of improper or unnecessary antibiotic use concerns the effect on the resident microbial ecosystem (microbiota) of human body. Indeed, as a consequence of antibiotic therapy the endogenous microbiota is altered or lost. Antibiotic treatment is typically followed by a decrease in the diversity of the microbiota, although the community is resilient and resembles the pretreatment state in a matter of days or weeks (3). The microbiota protects the host from incoming pathogens and changes in the microbiota as a consequence of antibiotic treatment can result in the dysregulation of host immune homeostasis and an increased susceptibility to disease (3). One of the most striking example is antibiotic-associated diarrhea, caused by the expansion of Clostridium difficile, and subsequent pseudomembranous colitis. It has been found that administration of antimicrobial substances alters the microbial balance of the vagina and suppresses certain bacterial groups (4). In the vaginal environment, antibiotic treatment can promote an overgrowth of anaerobic bacteria, which are commonly present in low concentrations in the vaginal flora of healthy women leading to a clinical condition, known as bacterial vaginosis (BV), characterized by reduction or absence of vaginal lactobacilli. However, BV pathogenesis still remains unknown and the antibiotic susceptibility of lactobacilli cannot be considered the only cause, given the high BV prevalence in the worldwide population, particularly in developing countries. The recurrence rate of BV is high, with more than 50% relapses within 6 months from specific antimicrobial therapy (5). The dominance of lactobacilli in healthy vaginal microbiota and its depletion in BV has given rise to the concept of oral or vaginal use of probiotic Lactobacillus strains for treatment and prevention of BV. The possibility of utilizing lactobacilli in the maintenance of a healthy state in the human female urogenital tract is based onthe capacity of these probiotic microorganisms to produce a barrier population (6) and to reduce vaginal proinflammatory cytokines (7). Probiotic administration could be suggested in cases of recurrent BV, to avoid repeated use of antibiotics and as prophylaxis for dismicrobism with depletion of lactobacilli in the female genital tract following systemic antibiotic administration.
Chiara Nardis, Paola Mastromarino
Department of Public Health and Infectious Diseases, Section of Microbiology, Sapienza University, Rome, Italy
