Evaluation of adhesin genes and risk factors associated with urinary tract infections by drug-resistant uropathogenic Escherichia coli in North of Iran.

BACKGROUND: Uropathogenic Escherichia coli (UPEC) isolates, have a wide variety of virulence factors to promote colonization and survival in the urinary tract. This study aimed to evaluate adhesin genes, biofilm formation ability, antibiotic resistance profiles of UPEC strains, and the related risk factors in patients with UTIs caused by drug-resistant UPEC. METHODOLOGY: A total of 105 UPEC isolates were evaluated for biofilm formation using 96-well microtiter plates, the presence of adhesin genes by PCR assay and the antimicrobial susceptibility pattern using the disk diffusion method. Demographic and clinical characteristics of patients were investigated to identify predisposing factors for drug-resistant isolates. RESULTS: Out of 105 UPEC isolates, 84.8% were positive for biofilm formation. Biofilm-producing isolates exhibited a significantly higher prevalence of fimH, kpsMTII, csgA, afa/draBC, and pap adhesin genes compared to non-biofilm-producing strains (p < 0.05). The results also revealed that 52.4% of the isolates were ESBL-producing, and 84.8% were multidrug-resistant (MDR). Further analysis of antibiotic susceptibility among ESBL-producing strains showed the highest resistance rates to ampicillin, ciprofloxacin, and trimethoprim-sulfamethoxazole. Conversely, the highest susceptibility, in addition to carbapenems, was observed for fosfomycin, amikacin, cefoxitin, and nitrofurantoin. We identified hypertension as a potential risk factor for infection with ESBL-producing UPEC strains. CONCLUSIONS: Our results revealed a significant rate of drug resistance among UPEC isolates obtained from UTIs in our region. This underscores the importance of monitoring the empirical use of antibiotics and identifying specific risk factors in our geographical area to guide the selection of appropriate empirical treatment for UTIs.

Global evaluation of the antibacterial activity of Ceftolozane/Tazobactam against ESBLs-producing Escherichia coli and Klebsiella pneumoniae: a systematic review and meta-analysis.

Background: Ceftolozane/Tazobactam is a ß-lactam/ß-lactamase inhibitor combination with a high range of efficacy and broad-spectrum action against multidrug-resistant bacterial strains. Objectives: The present study aimed to analyze the in vitro activity of Ceftolozane/Tazobactam against extended-spectrum ß-lactamases (ESBLs)-producing Escherichia coli (ESBLs-EC) and Klebsiella pneumonia (ESBLs-KP) in the published literature to provide international data on the antimicrobial stewardship programs. Design: Systematic review and meta-analysis. Methods: A systematic literature search was conducted on the Web of Science, Embase, PubMed, Scopus, and Google Scholar electronic databases from the beginning of databases to December 2022 to cover all published articles relevant to our scope. Results: At last, 31 publications that met our inclusion criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software. The pooled prevalence of Ceftolozane/Tazobactam susceptibility for ESBLs-EC and ESBLs-KP was estimated at 91.3% [95% confidence interval (CI): 90.1-92.5%] and 65.6% (95% CI: 60.8-70.2%), respectively. There was significant heterogeneity among the 31 studies for ESBLs-EC (χ2 = 91.621; p < 0.001; I2 = 67.256%) and ESBLs-KP (χ2 = 348.72; p < 0.001; I2 = 91.4%). Most clinical isolates of ESBLs-EC had MIC50 and MIC90 at a concentration of 0.5 and 2 µg/mL [minimum inhibitory concentration (MIC) at which 50% and 90% of isolates were inhibited], respectively. In contrast, most clinical isolates of ESBLs-KP had MIC50 and MIC90 at a concentration of 1 and 32 µg/mL, respectively. Conclusion: Based on the meta-analysis results, Ceftolozane/Tazobactam has a more promising in vitro antibacterial activity against ESBLs-EC isolates from different clinical sources than ESBLs-KP isolates. Therefore, Ceftolozane/Tazobactam can be a useful therapeutic drug as an alternative to carbapenems. Randomized clinical trials are needed to provide clinical evidence to support these observations.

Investigating of four main carbapenem-resistance mechanisms in high-level carbapenem resistant Pseudomonas aeruginosa isolated from burn patients.

BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen involved in many infections. Carbapenem-resistant P.aeruginosa has emerged as an important cause of infection in different hospitals worldwide. We aimed to determine frequencies of the four main resistance mechanisms [metallo-beta lactamase (MBL) production (blaIMP, blaVIM, blaSPM and blaNDM), overproduction of the MexAB-OprM and MexXY efflux pumps, overproduction of chromosome-encoded AmpC ß-lactamase, and reduced OprD expression] in high-level carbapenem-resistant P.aeruginosa isolated from patients with burns. METHODS: In a descriptive study, 107 P. aeruginosa isolates were collected from patients with burn injuries and tested for antibiotic susceptibility, by an E-test for carbapenems, an E-test for metallo-ß-lactamase producer isolates, and PCR to detect MBL genes. Furthermore, high-level carbapenem-resistant isolates were tested by real-time PCR for the expression levels of the mexB, mexY, ampC, and oprD genes. RESULTS: Amongst all P. aeruginosa isolates, 78.5%, 46.7%, and 15% were imipenem-, meropenem-, and doripenem-resistant, respectively; 72% of isolates were multidrug-resistant. The blaIMP and blaVIM genes were detected in 17.9% and 1.2% of isolates; respectively. The blaSPM and blaNDM genes were not observed. Among the resistant isolates, mexB overexpression (63.2%) was the most frequent mechanism, followed by mexY overexpression (52.6%), ampC overexpression (36.8%), and reduced oprD expression (21.1%). CONCLUSION: Emerging antimicrobial resistance in burn wound bacterial pathogens is a serious therapeutic challenge for clinicians. In the present study, most of the isolates were MDR. This finding indicated an alarming spread of resistant isolates and suggested that infection control strategies should be considered. Resistance to carbapenems is influenced by several factors, not all of which were evaluated in our study; however, the results showed that production of MBLs and overexpression of the mexB gene were the most frequent mechanisms in carbapenem-resistant isolates.

Oropharyngeal Colonization With Neisseria lactamica, Other Nonpathogenic Neisseria Species and Moraxella catarrhalis Among Young Healthy Children in Ahvaz, Iran.

BACKGROUND: Neisseria lactamica as one of the main commensal in oropharynx during the childhood is related to the induction of a natural immunity against meningococcal meningitis. Also Moraxella catarrhalis in oropharynx of children is a predisposing factor for otitis media infection. OBJECTIVES: The current study aimed to investigate the frequency of the N. lactamica, other nonpathogenic Neisseria spp. and M. catarrhalis in the oropharynx of young healthy children in Ahvaz, Iran by the two phenotypic tests and Polymerase Chain Reaction (PCR). MATERIALS AND METHODS: A total of 192 oropharyngeal swab samples of the young healthy children were studied during four months. Swabs were plated onto enriched selective media and non-selective media. Gram-negative and oxidase-positive diplococci were identified by several conventional biochemical tests. The PCR and sequencing were used to confirm the accuracy of laboratory diagnosis to identify N. lactamica and M. catarrhalis. RESULTS: Among 192 young healthy children with the mean age of 5.93 ± 2.5903 years, authors identified: N. lactamica (21.9%) in the age group of one to nine years; N. mucosa (6.3%); N. sicca (7.8%); N. cinerea (1.6%); N. subflava (biovar subflava) (4.2%); N. subflava (biovar perflava) (28.1%); N. subflava (biovar flava) (7.3%) and M. catarrhalis (42.7%). CONCLUSIONS: The young healthy children screening by colonization of N. lactamica and other nonpathogenic Neisseria spp. in oropharynx was the first report in Ahvaz, Iran. The study results demonstrated the high frequency of colonization of M. catarrhalis in the studied young healthy children other than Neisseria spp.

Comparative Proteomics Analysis of Two Strains of Neisseria meningitidis Serogroup B and Neisseria lactamica.

BACKGROUND: Antigenic similarities between Neisseria lactamica as a commensal species and N. meningitidis serogroup B (NmB) as an important cause of meningitis infection have been considered for the development of an effective vaccine based on their common proteins to prevent life-threatening bacterial meningitis. OBJECTIVES: The main aims of this study were to determine whole proteome profiles of N. lactamica strains and to compare them with whole proteome profile of a reference strain of NmB for identification of some of common proteins between the two species. MATERIALS AND METHODS: We compared the whole proteomic profiles of N. lactamica strains and a reference strain of NmB. Lysates from bacterial strains were resolved by two-dimensional gel electrophoresis (2-DE), followed by Coomassie Brilliant blue staining. Some of the protein spots were excised from the gel and subjected to matrix-assisted laser desorption/ionization-tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) analysis. RESULTS: The analysis of Coomassie-stained gels using ImageMaster 2D Platinum software identified approximately 800 reproducible protein spots in the range of pI 4.5 - 9.5 and M r of 8 - 100 kDa for each 2-DE gel of the studied bacterial strains. By comparing proteome maps of 2-DE gels, more than 200 common protein spots were recognized between the two species. Forty-eight common protein spots between the studied bacterial strains were identified by MALDI-TOF/TOF-MS. The results indicated that among the protein spots identified by MOLDI-TOF/TOF mass spectrometry, the groups of proteins included cell surface, energy metabolism, amino acid transport and metabolism, coenzyme metabolism, defense, multifunctional cellular processes, DNA, RNA and protein synthesis, ribosomal structure, regulatory functions, replication, transcription, translation, unknown and hypothetical proteins with unknown function. We found that N. lactamica strains have a proteome profile somewhat similar to each other and slightly different with NmB. CONCLUSIONS: These results show the usefulness of proteome analysis in successful identification of the common proteins between N. lactamica strains and NmB. This proteomics analysis is the starting point in the path of knowledge development about whole proteome profiles of N. lactamica strains.

Detection of Metallo-Beta Lactamases Among Carbapenem-Resistant Pseudomonas aeruginosa.

BACKGROUND: Carbapenems are important drugs used for the treatment of Pseudomonas aeruginosa infections, however metallo-ß-lactamases (MBL) are able to efficiently hydrolyze these classes of drugs. Immediate detection of the MBL-producing P. aeruginosa is necessary in order to accurately treat infections caused by this organism. OBJECTIVES: To determine the prevalence of MBL producing P. aeruginosa in burn and non-burn patients by two phenotypic tests and polymerase chain reaction (PCR) and to compare phenotypic tests with PCR. MATERIALS AND METHODS: A total of 223 non-duplicate strains of P. aeruginosa were collected from three teaching hospitals of Ahvaz, Iran. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) of carbapenems (imipenem, meropenem, doripenem and ertapenem) were determined by the Kirby-Bauer and E-test methods. Combined disk (CD) test, MBL E-test and PCR were performed for carbapenem-resistant P. aeruginosa isolates. RESULTS: Amongst all the P. aeruginosa isolates, 58.7% were resistant to imipenem while 31.8%, 13.5% and 74.4% were resistant to meropenem, doripenem and ertapenem, respectively. Amongst all the P. aeruginosa isolates, 44.4% were multidrug resistant and 13.45% were resistant to all of the carbapenems. The CD test with doripenem disk / 750 µg ethylene diamine tetra acetic acid (EDTA) had the highest efficiency compared to the other phenotypic tests. bla IMP and bla VIM genes were detected in 11.7% and 0.4% of isolates, respectively. bla SPM and bla NDM genes were not observed. CONCLUSIONS: Epidemiological and regional evaluation of MBL-producing P. aeruginosa through simple and inexpensive methods should be considered for effective treatment of carbapenem-resistant P. aeruginosa infections.

Characterization of Shigella strains in Iran by plasmid profile analysis and PCR amplification of ipa genes.

To characterize Shigella clinical strains, we studied 82 Shigella strains recovered from 719 stool samples of patients with bloody diarrhea in Shiraz, Iran, over the period from April to October 2003. Serological assay classified the Shigella isolates as follows: 61 (74.39%) Shigella sonnei isolates, 16 (19.51%) Shigella flexneri isolates, 3 (3.65%) Shigella boydii isolates, and 2 (2.43%) Shigella dysenteriae isolates. In an antibiogram test, all Shigella strains were susceptible to ceftazidime, ciprofloxacin, and ceftriaxone. They showed high degrees of sensitivity to nalidixic acid, gentamicin, cephalothin, and amikacin. Approximately 90.24% of the Shigella isolates were resistant to co-trimoxazole. The plasmid profile patterns of all strains were determined by a modified alkaline lysis method. The average number of plasmid bands for each strain was 9.5. By plasmid profile analysis we identified 56 genotypes among all isolates and 42, 14, 3, and 2 genotypes among the S. sonnei, S. flexneri, S. boydii, and S. dysenteriae strains, respectively. PCR assays showed that all isolates were positive for two virulence genes, ipaBCD and ipaH. In conclusion, these data mandate local monitoring of drug resistance and its consideration in the empirical therapy of Shigella infections. These results also demonstrate that plasmid profile analysis is more reliable than antibiotic susceptibility pattern analysis for the identification of Shigella epidemic strains isolated in Iran.