We aimed to characterise the staphylococcal cassette chromosome mec (SCCmec) type, genetic relatedness, biofilm formation and composition, icaADBC genes detection, icaD expression, and antibiotic susceptibility of planktonic and biofilm cells of Staphylococcus hominis isolates from blood. The study included 67 S. hominis blood isolates. Methicillin resistance was evaluated with the cefoxitin disk test. mecA gene and SCCmec were detected by multiplex PCR. Genetic relatedness was determined by pulsed-field gel electrophoresis. Biofilm formation and composition were evaluated by staining with crystal violet and by detachment assay, respectively; and the biofilm index (BI) was determined. Detection and expression of icaADBC genes were performed by multiplex PCR and real-time PCR, respectively. Antibiotic susceptibilities of planktonic cells (minimum inhibitory concentration, MIC) and biofilm cells (minimum biofilm eradication concentration, MBEC) were determined by the broth dilution method. Eighty-five percent (57/67) of isolates were methicillin resistant and mecA positive. Of the mecA-positive isolates, 66.7% (38/57) carried a new putative SCCmec type. Four clones were detected, with two to five isolates each. Among all isolates, 91% (61/67) were categorised as strong biofilm producers. Biofilm biomass composition was heterogeneous (polysaccharides, proteins and DNA). All isolates presented the icaD gene, and 6.66% (1/15) isolates expressed icaD. This isolate presented the five genes of ica operon. Higher BI and MBEC values than the MIC values were observed for amikacin, vancomycin, linezolid, oxacillin, ciprofloxacin, and chloramphenicol. S. hominis isolates were highly resistant to methicillin and other antimicrobials. Most of the detected SCCmec types were different than those described for S. aureus. Isolates indicated low clonality. The results indicate that S. hominis is a strong biofilm producer with an extracellular matrix with similar composition of proteins, DNA and N-acetylglucosamine; and presents high frequency and low expression of icaD gene. Biofilm production is associated with increased antibiotic resistance.

Chlamydia trachomatis is the causative agent of the most common bacterial sexually transmitted infection worldwide. The aim of this study was to investigate the frequency and genotypes of C. trachomatis in patients attending an obstetrics and gynecology clinic in Jalisco, Mexico and correlates them with sociodemographic, behavioral, and biological factors. C. trachomatis detection was performed in endocervical samples from 662 patients by direct fluorescence assay (DFA) and two PCR assays that amplified the phospholipase D endonuclease superfamily protein (PLDESP) and OmpA genes. Positive samples were genotyped using PCR–restriction fragment length polymorphism assays. Sociodemographic, behavioral, and biological data were collected. The mean age of the study population was 31 (range, 14–78) years. C. trachomatis positivity was detected by DFA in 16.7% (n = 111), PLDESP gene amplification in 14.2% (n = 94), and OmpA gene amplification in 14.5% (n = 96) of the population. Eight C. trachomatis genotypes were detected: E (39.6%), F (29.2%), D (15.6%), K (6.3%), L2 (3.1%), G, J, and I (2.1% each). C. trachomatis infection was associated with age, marital status, pregnancy, and hormonal contraceptive use (all p = 0.01); intrauterine device use and previous premature birth (both p = 0.03); and infection during pregnancy, previous ectopic pregnancy, pelvic inflammatory disease (PID), and green vaginal discharge (all p = 0.04). C. trachomatis genotype K was more likely to be detected in women histories of ≥2 sexual partners, genotype F was more likely in pregnant women, genotype L2 was more likely in women with PID, genotype D was more likely in women who had had infection during previous pregnancies, and genotype E was more likely in those with previous ectopic pregnancies and green vaginal discharge (all p = 0.01). The frequency of C. trachomatis in our population was higher than previously reported worldwide, but within the range reported for Mexico. Genotype E was detected most frequently in the study population. Infection by C. trachomatis and C. trachomatis genotypes K, F, D, and E was strongly associated with multiple sociodemographic, behavioral, and biological factors. C. trachomatis genotype L2 was detected in women with PID.

Acinetobacter baumannii has emerged as a threat to public health due to the high prevalence of multidrug-resistant isolates. Information regarding the clinical and molecular characterization of carbapenem-resistant A. baumannii (CRAB) infections in children is scarce. Our study aimed to describe the clinical and molecular characteristics of CRAB infections in children from third-level center in Mexico. Consecutive cases of CRAB infections were documented during 2017-2022. Clinical and demographic data were collected from clinical records. Mass spectrometry was used for the identification of the isolates. The identification of A. baumannii strains was confirmed by conducting a PCR assay targeting the gyrB sequence. In addition, the carbapenemase-encoding resistance genes were detected by PCR. 21 cases of CRAB infections were documented, 76% female. 62% were neonates. The median hospital length of stay at the time of positive culture was 37 days (interquartile range [IQR], 13-54). 64% of the isolates were recovered from bronchial secretions. A co-resistance rate greater than 60% was observed for most groups of antibiotics. All carbapenem-resistant isolates carried bla_OXA-24 genes. Bla_IMP genes were detected in half of the cases, with all strains co-harboring bla_OXA-24 genes. The present study demonstrated a high proportion of CRAB infections in the neonatal population, a high prevalence of co-resistance to antibiotics, and a high rate of isolates carrying bla_OXA-24 and bla_IMP genes. CRAB is a significant concern due to the mortality rate and the lack of therapeutic alternatives; implementing infection prevention and control programs is urgent to stop the spread of carbapenem-resistant Acinetobacter baumannii.

Sexually transmitted pathogens, coinfections and risk factors in patients attending obstetrics and gynecology clinics in Jalisco, Mexico

An alarming global public health and economic peril has been the emergence of antibiotic resistance resulting from clinically relevant bacteria pathogens, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species constantly exhibiting intrinsic and extrinsic resistance mechanisms against last-resort antibiotics like gentamycin, ciprofloxacin, tetracycline, colistin, and standard ampicillin prescription in clinical practices. The discovery and applications of antimicrobial peptides (AMPs) with antibacterial properties have been considered and proven as alternative antimicrobial agents to antibiotics. In this study, we have designed, produced, and purified a recombinant novel multifunctional hybrid antimicrobial peptide LL-37_Renalexin for the first time via the application of newly designed flexible GS peptide linker coupled with the use of our previously characterized small metal-binding proteins SmbP and CusF3H+ as carrier proteins that allow for an enhanced bacterial expression, using BL21(DE3) and SHuffle T7(DE3) Escherichia coli strains, and purification of the hybrid peptide via immobilized metal affinity chromatography. The purified tag-free LL-37_Renalexin hybrid peptide exhibited above 85% reduction in bacteria colony-forming units and broad-spectrum antimicrobial effects against Staphylococcus aureus, Escherichia coli, Methicillin-resistant Staphylococcus aureus (MRSA), and Klebsiella pneumoniae bacteria clinical isolates at a lower minimum inhibition concentration level (10–33 μM) as compared to its counterpart single-AMPs LL-37 and Renalexin (50–100 μM). Key points: • The hybrid antimicrobial peptide LL-37_Renalexin has been designed using a GS linker. • The peptide was expressed with the carrier proteins SmbP and CusF3H+. • The hybrid peptide shows antibacterial potency against clinical bacterial isolates.