Bacterial Diversity and Antibiotic Resistance Patterns of Community-Acquired Urinary Tract Infections in Mega Size Clinical Samples of Egyptian Patients: A Cross-Sectional Study

BACKGROUND

 Community-acquired urinary tract infection (UTI) is one of the most common infectious diseases nowadays. Alarming increased levels of antimicrobial resistance are developing globally which limit treatment options and may lead to life-threatening problems.

AIM

Our study aimed to collect surveillance data on non-hospitalized Egyptian UTI cases and to develop strategies against multidrug-resistant pathogens (MDR). According to our knowledge, this is the first study to screen this high number (15,252 urine samples) in a short period (three months), providing valuable data on resistance profiles in non-hospitalized Egyptian UTI patients.

METHODS

A total of 15,252 urine samples were collected from different patients. Positive cultures were identified using a semi-quantitative method. Kirby-Bauer's disc diffusion method was used for antibiotic susceptibility testing, the double disc diffusion method was used for extended-spectrum beta-lactamases-producing strains, and the Chi-square test was used for statistical data processing.

RESULTS

The results showed 61% positive cultures, females accounted for 67.5%. Infants and elderly patients showed the highest positive cultures (74.4% and 69.2%, respectively). Despite Escherichia coli being the most common uropathogen (47.19%), Klebsiella species(24.42%) were the most MDR and extended-spectrum β-lactamase (ESBL)-producing organisms. E. coli and Klebsiella spp. displayed increased resistance to cephalosporins (75% and 81%, respectively). In contrast, both organisms displayed high sensitivity to carbapenems. Unlike Klebsiella spp., E. coli was highly sensitive (92%) to first-line treatment (nitrofurantoin) for UTI. Moreover, trimethoprim/sulfamethoxazole showed higher sensitivity rates compared to other nations.

CONCLUSION

 Despite Escherichia coli being the most often identified bacteria in our isolates Klebsiella spp. displayed higher resistance to the majority of tested antibiotics. Fortunately, trimethoprim/sulfamethoxazole significantly increased sensitivity, especially against E. coli. However, both species showed high rates of cephalosporin resistance. Moreover, It is important to promote Egypt's national action plan for antimicrobial resistance in collaboration with the World Health Organization, especially in the community to minimize the chance of bacterial resistance in the Egyptian community.

Roles of Lipopolysaccharide Glycosyltransferases in Maintenance of Helicobacter pylori Morphology, Cell Wall Permeability, and Antimicrobial Susceptibilities

Helicobacter pylori has a unique lipopolysaccharide structure that is essential in maintaining its cell envelope integrity and imbues the bacterium with natural resistance to cationic antimicrobial peptides (CAMPs). Our group has recently elucidated the complete set of LPS glycosyltransferase genes in H. pylori reference strain G27. Here, with a series of eight systematically constructed LPS glycosyltransferase gene mutants (G27ΔHP1578, G27ΔHP1283, G27ΔHP0159, G27ΔHP0479, G27ΔHP0102, G27ΔwecA, G27ΔHP1284 and G27ΔHP1191), we investigated the roles of H. pylori LPS glycosyltransferases in maintaining cell morphology, cell wall permeability, and antimicrobial susceptibilities. We demonstrated that deletion of these LPS glycosyltransferase genes did not interfere with bacterial cell wall permeability, but resulted in significant morphological changes (coccoid, coiled "c"-shape, and irregular shapes) after 48 h growth as compared to the rod-like cell shape of the wild-type strain. Moreover, as compared with the wild-type, none of the LPS mutants had altered susceptibility against clarithromycin, levofloxacin, amoxicillin, tetracycline, and metronidazole. However, the deletion of the conserved LPS glycosyltransferases, especially the O-antigen-initiating enzyme WecA, displayed a dramatic increase in susceptibility to the CAMP polymyxin B and rifampicin. Taken together, our findings suggest that the LPS glycosyltransferases play critical roles in the maintenance of the typical spiral morphology of H. pylori, as well as resistance to CAMPs and rifampicin. The LPS glycosyltransferases could be promising targets for developing novel anti-H. pylori drugs.

Antimicrobial Susceptibilities and Laboratory Profiles of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis Isolates as Agents of Urinary Tract Infection in Lebanon: Paving the Way for Better Diagnostics

Background: Urinary tract infections (UTIs) are major healthcare problems that are usually treated empirically. However, antimicrobial resistance has been increasing across many settings. This study aims to elucidate the antibiotic resistance profiles of three common uropathogens, Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), and Proteus mirabilis (P. mirabilis) and compare between extended spectrum beta-lactamase (ESBL) and non-ESBL strains among Lebanese patients. Methods: This retrospective study was conducted at multiple tertiary healthcare centers in South Lebanon, between January and September 2017, including 551 patients of all age groups. Demographic, clinical, and laboratory data of patients were collected and analyzed statistically. Results: The prevalence of UTI in Lebanon was highest in adults between 19 and 64 years (44%). E. coli was the predominant uropathogenic organism (67.1%) followed by K. pneumoniae (10%) and P. mirabilis (3.7%). ESBL represented 32.9% of the UTI agents. The three common uropathogens studied were found to be most susceptible to imipenem (100%) and meropenem (100%). Interestingly, 115 (25.1%) out of the 458 E. coli isolates were resistant to more than eight antibiotics while 107 (23.4%) were susceptible to all antibiotics studied. Conclusions: Our study underlined the importance of adequate antimicrobial prescription for UTIs in Lebanon to avoid multidrug resistance.

Antimicrobial Susceptibilities of Oral Isolates of Abiotrophia and Granulicatella According to the Consensus Guidelines for Fastidious Bacteria

Background: The genera Abiotrophia and Granulicatella, previously known as nutritionally variant streptococci (NVS), are fastidious bacteria requiring vitamin B₆ analogs for growth. They are members of human normal oral microbiota, and are supposed to be one of the important pathogens for so-called "culture-negative" endocarditis. Methods: The type strains and oral isolates identified, by using both phenotypic profiles and the DNA⁻DNA hybridization method, were examined for susceptibilities to 15 antimicrobial agents including penicillin (benzylpenicillin, ampicillin, amoxicillin, and piperacillin), cephem (cefazolin, ceftazidime, ceftriaxone, and cefaclor), carbapenem (imipenem), aminoglycoside (gentamicin), macrolide (erythromycin), quinolone (ciprofloxacin), tetracycline (minocycline), glycopeptide (vancomycin), and trimethoprim-sulfamethoxazole complex. The minimum inhibitory concentration and susceptibility criterion were determined, according to the consensus guideline from the Clinical and Laboratory Standards Institute. Results: Isolates of Abiotrophia defectiva were susceptible to ampicillin, amoxicillin ceftriaxone, cefaclor, imipenem, ciprofloxacin, and vancomycin. Isolates of Granulicatella adiacens were mostly susceptible to benzylpenicillin, ampicillin, amoxicillin, cefazolin, ceftriaxone, imipenem, minocycline, and vancomycin. The susceptibility profile of Granulicatella elegans was similar to that of G. adiacens, and the susceptibility rate was higher than that of G. adiacens. Conclusions: Although Abiotrophia and Granulicatella strains are hardly distinguishable by their phenotypic characteristics, their susceptibility profiles to the antimicrobial agents were different among the species. Species-related differences in susceptibility of antibiotics should be considered in the clinical treatment for NVS related infections.

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Use with Positive Blood Cultures: Methodology, Performance, and Optimization

Early initiation of effective antibiotics for septic patients is essential for patient survival. Matrix-assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized clinical microbiology for isolate identification and has the possibility to impact how blood culture testing is performed. This review discusses the various uses of MALDI-TOF MS for the identification and susceptibility testing of positive blood cultures, the performance of these methods, and the outcomes involved with its implementation.

Investigation of toxin gene diversity and antimicrobial resistance of Clostridium difficile strains

The incidence of Clostridium difficile infection (CDI) has been previously reported in a number of studies. However, data collected from the Chinese population is limited. In the present study, the diversity of the toxin genes, tcdA and tcdB, of 57 Clostridium difficile (C. difficile) isolates from a Chinese population were investigated by polymerase chain reaction (PCR) (38 A⁺B⁺, 14 A^-B⁺ and 5 A^-B^-). Quantitative PCR was used to check the expression of these two genes and it was found that the genes were not expressed by all the strains. The absence of tcdA or tcdB expression in certain strains could be due to the lower expression of tcdD and the higher expression of tcdC, which are positive and negative regulators for these two toxin genes, respectively. In addition, the antimicrobial susceptibilities of 57 isolates were investigated. Therefore, these data would aid in the future prevention of CDI outbreaks and improve the understanding of the infection.

Antimicrobial susceptibility patterns of Ureaplasma species and Mycoplasma hominis in pregnant women

BACKGROUND

Genital mycoplasmas colonise up to 80% of sexually mature women and may invade the amniotic cavity during pregnancy and cause complications. Tetracyclines and fluoroquinolones are contraindicated in pregnancy and erythromycin is often used to treat patients. However, increasing resistance to common antimicrobial agents is widely reported. The purpose of this study was to investigate antimicrobial susceptibility patterns of genital mycoplasmas in pregnant women.

METHODS

Self-collected vaginal swabs were obtained from 96 pregnant women attending an antenatal clinic in Gauteng, South Africa. Specimens were screened with the Mycofast Revolution assay for the presence of Ureaplasma species and Mycoplasma hominis. The antimicrobial susceptibility to levofloxacin, moxifloxacin, erythromycin, clindamycin and tetracycline were determined at various breakpoints. A multiplex polymerase chain reaction assay was used to speciate Ureaplasma positive specimens as either U. parvum or U. urealyticum.

RESULTS

Seventy-six percent (73/96) of specimens contained Ureaplasma spp., while 39.7% (29/73) of Ureaplasma positive specimens were also positive for M. hominis. Susceptibilities of Ureaplasma spp. to levofloxacin and moxifloxacin were 59% (26/44) and 98% (43/44) respectively. Mixed isolates (Ureaplasma species and M. hominis) were highly resistant to erythromycin and tetracycline (both 97% resistance). Resistance of Ureaplasma spp. to erythromycin was 80% (35/44) and tetracycline resistance was detected in 73% (32/44) of Ureaplasma spp. Speciation indicated that U. parvum was the predominant Ureaplasma spp. conferring antimicrobial resistance.

CONCLUSIONS

Treatment options for genital mycoplasma infections are becoming limited. More elaborative studies are needed to elucidate the diverse antimicrobial susceptibility patterns found in this study when compared to similar studies. To prevent complications in pregnant women, the foetus and the neonate, routine screening for the presence of genital mycoplasmas is recommended. In addition, it is recommended that antimicrobial susceptibility patterns are determined.