The effect of lactic acid bacteria isolates on the urinary tract pathogens to infants in vitro

Emerging Non-Antibiotic Options Targeting Uropathogenic Mechanisms for Recurrent Uncomplicated Urinary Tract Infection

Urinary tract infections (UTIs) are the most frequent bacterial infections in the clinical setting. Even without underlying anatomic or functional abnormalities, more than 40% of women experience at least one UTI in their lifetime, of which 30% develop recurrent UTIs (rUTIs) within 6 months. Conventional management with antibiotics for rUTIs may eventually lead to the development of multidrug-resistant uropathogens. Targeting of the pathogenicity of rUTIs, the evolution of uropathogenic Escherichia coli (UPEC), and inadequate host defenses by immune responses should be explored to provide non-antibiotic solutions for the management of rUTIs. The adaptive evolution of UPEC has been observed in several aspects, including colonization, attachment, invasion, and intracellular replication to invade the urothelium and survive intracellularly. Focusing on the antivirulence of UPEC and modulating the immunity of susceptible persons, researchers have provided potential alternative solutions in four categories: antiadhesive treatments (i.e., cranberries and D-mannose), immunomodulation therapies, vaccines, and prophylaxis with topical estrogen therapy and probiotics (e.g., Lactobacillus species). Combination therapies targeting multiple pathogenic mechanisms are expected to be a future trend in UTI management, although some of these treatment options have not been well established in terms of their long-term efficacy. Additional clinical trials are warranted to validate the therapeutic efficacy and durability of these techniques.

Non-antibiotic Approaches to Preventing Pediatric UTIs: a Role for D-Mannose, Cranberry, and Probiotics?

PURPOSE OF REVIEW

While antibiotics have been a staple in the management and even prevention of urinary tract infections (UTIs), it is not without significant consequences due to intolerance and development of antibiotic resistant bacteria. These concerns necessitate alternatives to antibiotic use in the management of pediatric UTIs. This review seeks to evaluate non-antibiotic means of preventing UTI in the pediatric population.

RECENT FINDINGS

The search for preventative alternatives to antibiotics has included D-mannose, cranberry, and probiotics. These products similarly work through competitive inhibition of uropathogens in the urinary tract. Pediatric studies exist highlighting the use of cranberry extract/juice and probiotics in UTI prevention, although significant heterogeneity amongst studies have limited overarching recommendations for their use. Data of D-mannose use is extrapolated from adult literature. More studies are required in the utility of each treatment, with some emphasis on larger sample sizes and clarifications regarding dosing and formulation.

Enterococcus faecalis inhibits Klebsiella pneumoniae growth in polymicrobial biofilms in a glucose-enriched medium

Catheter-related urinary tract infections are one of the most common biofilm-associated diseases. Within biofilms, bacteria cooperate, compete, or have neutral interactions. This study aimed to investigate the interactions in polymicrobial biofilms of Klebsiella pneumoniae and Enterococcus faecalis, two of the most common uropathogens. Although K. pneumoniae was the most adherent strain, it could not maintain dominance in the polymicrobial biofilm due to the lactic acid produced by E. faecalis in a glucose-enriched medium. This result was supported by the use of E. faecalis V583 ldh-1/ldh-2 double mutant (non-producer of lactic acid), which did not inhibit the growth of K. pneumoniae. Lyophilized cell-free supernatants obtained from E. faecalis biofilms also showed antimicrobial/anti-biofilm activity against K. pneumoniae. Conversely, there were no significant differences in planktonic polymicrobial cultures. In summary, E. faecalis modifies the pH by lactic acid production in polymicrobial biofilms, which impairs the growth of K. pneumoniae.

Lactic Acid Bacteria and Their Bacteriocins: Classification, Biosynthesis and Applications against Uropathogens: A Mini-Review

Several lactic acid bacteria (LAB) isolates from the Lactobacillus genera have been applied in food preservation, partly due to their antimicrobial properties. Their application in the control of human pathogens holds promise provided appropriate strains are scientifically chosen and a suitable mode of delivery is utilized. Urinary tract infection (UTI) is a global problem, affecting mainly diabetic patients and women. Many uropathogens are developing resistance to commonly used antibiotics. There is a need for more research on the ability of LAB to inhibit uropathogens, with a view to apply them in clinical settings, while adhering to strict selection guidelines in the choice of candidate LAB. While several studies have indicated the ability of LAB to elicit inhibitory activities against uropathogens in vitro, more in vivo and clinical trials are essential to validate the efficacy of LAB in the treatment and prevention of UTI. The emerging applications of LAB such as in adjuvant therapy, oral vaccine development, and as purveyors of bioprotective agents, are relevant in infection prevention and amelioration. Therefore, this review explores the potential of LAB isolates and their bacteriocins to control uropathogens, with a view to limit clinical use of antibiotics.

Efficacy of Locally Isolated Lactic Acid Bacteria Against Antibiotic-Resistant Uropathogens

Background:

Antibiotic resistance represents a serious global health threat to public health, so infections such as pneumonia and urinary tract infection (UTI) are becoming harder to treat. Therefore, it is necessary to develop an action plan to restrain the problem of antibiotic resistance. One approach in UTI control could be the use of lactobacilli because these indigenous inhabitants in human intestine have been found to play an important role in protecting the host from various infections.

Objectives:

We sought to check the efficacy of locally isolated Lactobacillus species to eradicate antibiotic-resistant pathogenic bacteria causing UTI.

Materials and Methods:

Lactic acid bacteria isolated from spoiled fruits and vegetables and grown in MRS medium were screened against multi-drug-resistant Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus fecalis.

Results:

Fifty-four lactic acid bacteria were isolated from spoiled fruits and vegetables, of which 11 Gram-positive and catalase-negative Lactobacillus isolates were identified by carbohydrate assimilation profiles as Lactobacillus acidophilus, L. paracasei, L. delbrueckii, L. casei, L. helveticus, L. brevis, L. salivarius, L. fermentum, L. rhamnosus, L. animalis, and L. plantarum. The latter organism had the highest abundance of all the samples, so its isolates were also verified through 16S rRNA gene sequencing. The isolated Lactobacilli were screened against multi-drug-resistant uropathogens, viz. C. albicans, P. aeruginosa, K. pneumoniae, E. fecalis, and E. coli. The growth inhibition zone (GIZ) was over 10 mm against all the uropathogenic test organisms, where L. fermentum and L. plantarum strains demonstrated remarkable inhibitory activities against E. coli and E. faecalis, with a GIZ up to 28 mm. The susceptibility test to 16 antibiotics showed multidrug resistance (3 to 5 antibiotics) among all the tested uropathogens.

Conclusions:

The obtained results revealed that all the Lactobacillus isolates displayed antimicrobial activity against 6 out of 7 antibiotic-resistant uropathogens, indicating that these bacteria could represent a good ecological plan for the control and prevention of UTI.

Evaluation and management of recurrent urinary tract infections in children: state of the art

Urinary tract infections (UTIs) represent an important cause of febrile illness in young children and can lead to renal scarring and kidney failure. However, diagnosis and treatment of recurrent UTI in children is an area of some controversy. Guidelines from the American Academy of Pediatrics, National Institute for Health and Clinical Excellence and European Society of Paediatric Radiology differ from each other in terms of the diagnostic algorithm to be followed. Treatment of vesicoureteral reflux and antibiotic prophylaxis for prevention of recurrent UTI are also areas of considerable debate. In this review, we collate and appraise recently published literature in order to formulate evidence-based guidance for the diagnosis and treatment of recurrent UTI in children.

Lactococcus lactis as an adjuvant and delivery vehicle of antigens against pneumococcal respiratory infections

Most studies of Lactococcus lactis as delivery vehicles of pneumococcal antigens are focused on the effectiveness of mucosal recombinant vaccines against Streptococcus pneumoniae in animal models. At present, there are three types of pneumococcal vaccines: capsular polysaccharide pneumococcal vaccines (PPV), protein-polysaccharide conjugate pneumococcal vaccines (PCV) and protein-based pneumococcal vaccines (PBPV). Only PPV and PCV have been licensed. These vaccines, however, do not represent a definitive solution. Novel, safe and inexpensive vaccines are necessary, especially in developing countries. Probiotic microorganisms such as lactic acid bacteria (LAB) are an interesting alternative for their use as vehicles in pneumococcal vaccines due to their GRAS (Generally Recognized As Safe) status. Thus, the adjuvanticity of Lactococcus lactis by itself represents added value over the use of other bacteria, a question dealt with in this review. In addition, the expression of different pneumococcal antigens as well as the use of oral and nasal mucosal routes of administration of lactococcal vaccines is considered. The advantages of nasal live vaccines are evident; nonetheless, oral vaccines can be a good alternative when the adequate dose is used. Another point addressed here is the use of live versus inactivated vaccines. In this sense, few researchers have focused on inactivated strains to be used as vaccines against pneumoccoccus. The immunogenicity of live vaccines is better than the one afforded by inactivated ones; however, the probiotic-inactivated vaccine combination has improved this matter considerably. The progress made so far in the protective immune response induced by recombinant vaccines, the successful trials in animal models and the safety considerations of their application in humans suggest that the use of recombinant vaccines represents a good short-term option in the control of pneumococcal diseases.

Administration of a probiotic associated with nasal vaccination with inactivated Lactococcus lactis-PppA induces effective protection against pneumoccocal infection in young mice

Streptococcus pneumoniae is a serious public health problem, especially in developing countries, where available vaccines are not part of the vaccination calendar. We evaluated different respiratory mucosa immunization protocols that included the nasal administration of Lactococcus lactis-pneumococcal protective protein A (PppA) live, inactivated, and in association with a probiotic (Lc) to young mice. The animals that received Lc by the oral and nasal route presented the highest levels of immunoglobulin (Ig)A and IgG anti-PppA antibodies in bronchoalveolar lavages (BAL) and IgG in serum, which no doubt contributed to the protection against infection. However, only the groups that received the live and inactivated vaccine associated with the oral administration of the probiotic were able to prevent lung colonization by S. pneumoniae serotypes 3 and 14 in a respiratory infection model. This would be related to a preferential stimulation of the T helper type 1 (Th1) cells at local and systemic levels and with a moderate Th2 and Th17 response, shown by the cytokine profile induced in BAL and by the results of the IgG1/IgG2a ratio at local and systemic levels. Nasal immunization with the inactivated recombinant strain associated with oral Lc administration was able to stimulate the specific cellular and humoral immune response and afford protection against the challenge with the two S. pneumoniae serotypes. The results obtained show the probiotic-inactivated vaccine association as a valuable alternative for application to human health, especially in at-risk populations, and are the first report of a safe and effective immunization strategy using an inactivated recombinant strain.