Erythromycin Resistance Research Articles

Prevalence of nasal carriers of methicillin-resistant Staphylococcus aureus in primary health care units in Brazil.

ABSTRACTNasal carriage of Staphylococcus aureus by healthcare workers is of great clinical importance as it facilitates the contamination of medical devices and cross-transmission. However, studies regarding the epidemiology and dissemination of S. aureus and Methicillin-resistant S. aureus (MRSA) within the Primary Health Care in Brazil are scarce. The current study aimed to detect and characterize S. aureus and MRSA strains from the nasal cavities of 63 healthcare working in primary health care units in order to determine the prevalence of S. aureus and MRSA, biofilm formation and resistance profile of these isolates. PCR reactions were performed for detecting mecA, icaA and icaD genes. The phenotypic antimicrobial susceptibility was assessed by the disk diffusion method and biofilm formation by the Congo Red Agar (CRA) method. The MRSA isolates were typed for the Staphylococcal Cassette Chromosome mec (SCCmec). The prevalence of nasal carriage of S. aureus was 74.6%, of which 72.3% were MRSA carrying SCCmec type I (24.4%), III (34.1%), IV (36.6%). Two (4.9%) isolates presented a non-typeable cassette by the performed technique. The antimicrobial susceptibility evaluation evidenced penicillin resistance in 66.1% of S. aureus, erythromycin resistance in 49.2%, while 37.3% were resistant to oxacillin, 28.8% to cefoxitin, 5.1% to levofloxacin and 5.1% to clindamycin. All isolates were biofilm producers and 96.6% of the strains contained the ica biofilm-forming genes (icaA and/or icaD). We have demonstrated a high prevalence of S. aureus and MRSA carriage among health care working in Primary Health Care units, the presence of SCCmec types I, III and IV, in addition to their high ability to form biofilm, factors that possibly contribute to the dissemination and persistence of these pathogens within the primary care services. These observations highlight the importance of broadening the perspective of Health Care-Associated Infections prevention, including all health care levels, which are currently little explored. In addition, the dynamics and resistance mechanisms of S. aureus transmission still need to be further clarified to enable the implementation of more effective prevention measures.

Determination of Capsular Serotypes, Antibiotic Susceptibility Pattern, and Molecular Mechanism of Erythromycin Resistance among Clinical Isolates of Group B Streptococcus in Isfahan, Iran.

Background:Documented streptococcal resistance to erythromycin has recently been raised. The aim of this study is to identify the molecular mechanism of erythromycin resistance among group B Streptococcus (GBS) strains and to correlate with the clinical origin of strains.Materials and Methods:A total number of 134 colonizing (n = 36), invasive (n = 36), noninvasive (n = 46), and asymptomatic (n = 16) GBS isolates were characterized by the detection of dltS gene, capsular serotyping, antibiotic susceptibility profiles using disc diffusion method, and screening of the ermB, ermTR, and mefA resistance genes.Results:The distribution of capsular serotypes was as follow: serotype III (24.6%), Ia (21.6%), V (17.9%), Ib (14.9%), II (8.9%), IV (8.9%), VI (1.5%), and VII (1.5%). From 134 GBS isolates, 51 (38%) isolates were resistant to erythromycin. The constitutive macrolide lincosamide streptogrmin B (MLSB) was the most common resistance phenotype (62.7%), followed by inducible MLSB (27.4%) and M phenotype (9.8%). Erythromycin resistance rate was higher among asymptomatic GBS strains (13/16, 81.2%). Serotype III was the most prevalent type among resistant isolates (41.1%). The ermB gene highly distributed among resistant strains (64.7%), followed by ermTR (21.5%) and mefA (9.8%). The ermB gene was related to constitutive MLSB phenotype (84.3%, P < 0.05) and serotypes III (61.9%), Ib (87.5%), and V (83.3%). All M phenotype strains harbored mefA gene and were in association with serotype Ia (90%).Conclusion:The current study suggests that ribosomal modification with erm genes is the main mechanism of erythromycin resistance. Because of relatively high prevalence of erythromycin resistance, double disc test highly recommended for GBS disease treatment and intrapartum prophylaxis among penicillin intolerant patients in our region.

High incidence of multidrug resistance and class 1 and 2 integrons in Escherichia coli isolated from broiler chickens in South of Iran.

The objective was to investigate the multidrug resistance and presence of class 1 and 2 integrons in 300 Escherichia coli isolates obtained from 20 broiler farms during three rearing periods (one-day-old chicks, thirty-day-old chickens, and one day before slaughter) in Fars, South Iran. Results showed that 81.00%, 82.00%, and 85.00% of isolates were multidrug-resistant on the first day, thirty-day-old chickens, and one day before slaughter, respectively. Multidrug-resistant E. coli isolates were further examined for the presence of class 1 and 2 integrons using PCR assay. The existence of class 1 integron-integrase gene (intI1) was confirmed in 68.40%, 72.70%, and 60.90% of multidrug-resistant isolates from stage 1, stage 2, and stage 3 of the rearing period, respectively. The frequency of class 2 integron-integrase gene (intI2) during the first to the third stage of sampling was 2.60%, 25.50%, and 30.40%. Also, sequence analysis of the cassette arrays within class 1 integron revealed the presence of the genes associated with resistance for trimethoprim (dfrA), streptomycin (aadA), erythromycin (ereA), and orfF genes. The results revealed that percentages of antimicrobial resistance in E. coli isolates were significantly higher in the middle and end stages of the rearing period. In conclusion, widespread dissemination of class 1 integrons in all three stages and rising trends of class 2 integrons existence in E. coli isolates during the rearing period of broiler chickens could exacerbate the spread of resistance factors among bacteria in the poultry industry. Future research is needed to clarify its implication for human health.

Rate and Mechanism of Erythromycin Resistance in Streptococcus pyogenes in Beni-Suef University Hospital

Background: Group A streptococci (GAS) is a major cause of morbidity and mortality. Erythromycin is an effective macrolide antibiotic for treating GAS infections. However, GAS macrolide resistance has been increased due to either an efflux mechanism (M phenotype), encoded by mef A gene, or by methylation of the ribosomal target resulting in resistance to macrolide, lincosamide, and streptogramin B (MLS) antibiotics. Methylase can be expressed either constitutively (cMLS phenotype) or inducibly (iMLS phenotype). Objectives: The present study aimed to find out frequency of S. pyogenes isolated from patients with upper respiratory tract infections at Beni-Suef University Hospital, determine rate and mechanism of macrolide resistance. Methodology: The present study was conducted on patients with upper respiratory tract infections attended to otorhinolaryngology clinic, Beni-Suef University Hospital, Egypt, in the period from February to December 2015. Detailed history taking was carried and clinical findings were obtained. Throat or ear swabs were taken and processed by conventional bacteriological methods. S. pyogenes isolates were further tested to determine erythromycin resistance phenotype by D- test, MIC of Erythromycin by tube broth dilution method and for mef A gene by PCR. Results: Forty two S. pyogenes isolates were identified from (100) swabs taken from either ear or throat specimens (42%), isolates resistance to erythromycin and clindamycin was 83.3% (35) and 31% (13) respectively. The pattern of macrolide resistance was 31% (13/ 42) cMLS phenotype, 52.3% (22/42) M phenotype and no isolate was iMLSB phenotype. Most strains with M phenotype expressed low-level macrolide resistance (MIC 1-4μg/ml), while cMLSB isolates showed a high level of erythromycin resistance (MIC ≥64 μg/ml) (highly significant: p-value 0.0001). The results confirmed a strong correlation between the M phenotype and the mef A gene in GAS (highly significant: p-value =0.001). Conclusion: Incidence of erythromycin resistance was evident among the isolates. To preserve the necessary efficacy, limited use of erythromycin is recommended.

Analysis of Kytococcus sedentarius Strain Isolated from a Dehumidifier Operating in a University Lecture Theatre: Systems for Aerobic Respiration, Resisting Osmotic Stress, and Sensing Nitric Oxide

A strain of Kytococcus sedentarius was isolated from a dehumidifier operating in a university lecture theatre. Genome analysis and phenotypic characterisation showed that this strain, K. sedentarius MBB13, was a moderately halotolerant aerobe with a branched aerobic electron transport chain and genes that could contribute to erythromycin resistance. The major compatible solute was glycine betaine, with ectoine and proline being deployed at higher osmolarities. Actinobacteria possess multiple WhiB-like (Wbl) regulatory proteins, and K. sedentarius MBB13 has four (WhiB1, WhiB2, WhiB3, and WhiB7). Wbls are iron-sulfur proteins that regulate gene expression through interactions with RNA polymerase sigma factors and/or other regulatory proteins. Bacterial two-hybrid analyses suggested that WhiB1 and WhiB2, but not WhiB3 and WhiB7, interact with the C-terminal domain of the major sigma factor, σ^A; no interaction was detected between any of the Wbl proteins and the only alternative sigma factors, σ^B, σ^H, or σ^J. The interaction between σ^A and WhiB1 or WhiB2 was disrupted in a heterologous system under growth conditions that produce nitric oxide and the iron-sulfur clusters of the isolated WhiB1 and WhiB2 proteins reacted with nitric oxide. Thus, K. sedentarius strain exhibits the major phenotypic characteristics of the type strain and a comprehensive examination of the interactions between its four Wbl proteins and four sigma factors suggested that the Wbl proteins all operate through interaction with σ^A.

Captive Snakes from Brazil as Carriers of Multidrug-Resistant Enterococci

Brazil has one of the most diverse herpetofauna and snakebites are an important health issue. The oral cavity of snakes harbored a wide range of bacteria. Enterococci have been isolated from animals, however, few studies have taken in snakes. In this sense, the present study aimed to evaluate Entero-coccus spp. and their virulence attributes including antimicrobial resistance in oral cavities of healthy snake species in Brazil. Oral swabs from wild and captive snakes were screened for enterococci distri-bution, antimicrobial susceptibility, resistance and virulence genes, and CRISPRs elements by PCR. Overall, 116 enterococci were detected and Enterococcus faecalis was dominant in all snake species, followed by E. faecium, E. avium, and E. hirae. Interestingly, no resistant enterococci were detected in wild snakes. In contrast, captive snakes were found to be carriers of resistant strains, including resistance to erythromycin, rifampicin, norfloxacin, ciprofloxacin, and tetracycline. Enterococcus faecium (50%) and E. faecalis (15.78%) isolates were multi-drug-resistant. Erythromycin resistance genes, the msrC and ermB, were detected in 13.33% and 6.67% of the isolates, respectively. The tetM (70%), tetL (30%) and tetS (10%) genes were detected in the tetracycline-resistant strains. Among the virulence genes, gelE was the most frequent in all strains. CRISPR1-cas, orphan CRISPR2, and CRISPR3-cas elements were present in 16.03%, 15.79%, and 18.31% of the isolates, respectively. No antibiotic resistance was associated with CRISPRs. In conclusion, resistant enterococci in captive snakes are the result of confinement, antibiotic therapy and human contact. Resistant bacteria in captive snakes provide crucial information about public health safety.

Staphylococcus aureus’un Onbeş Yılda Metisilin Direnç ve Antibiyogram Direnç Profilinin ve Görülme Sıklığının Değişimi

Objective: The aim of this retrospective study was to evaluate the rate and antimicrobial resistance profile of community-acquired (CA) and hospital-acquired (HA) methicillin-resistant and sensitive Staphylococcus aureus (MRSA, MSSA) strains between 2004 and 2019. Method: Within the scope of the research, the rate of MRSA and MSSA and the change in antimicrobial resistance profile over time were investigated using two research data of 210 Staphylococcus aureus strains isolated in 2004, and 401 in 2019. Results: While any significant change was not seen in the rates of CA-MRSA (32.4%) and CA-MSSA (67.6%) in 2004, and of CA-MRSA (31.6%) and CA-MSSA (68.4%) in 2019, the prevalence of HA-MRSA decreased by 56.1% in 2004 and 30.7% in 2019 and of HA-MSSA increased by 43.9% in 2004 and 69.3% in 2019. No resistance to vancomycin and teikoplanin was observed in MRSA strains. Resistance of CA-MRSA against ciprofloxacin, levofloxacin, clindamycin and gentamicin decreased. In CA-MSSA an increase of penicillin resistance as well as a decrease in gentamicin resistance was observed. In resistance of HA-MRSA against ciprofloxacin, levofloxacin, erythromycin, clindamycin, gentamicin decreased. HA-Resistance of MSSA against fusidic acid increased and against ciprofloxacin and trimethoprim/sulfamethoxazole and erythromycin resistance decreased. Conclusion: It was found that the rate of HA-MRSA decreased during the given period of 15 years. Vancomycin or teicoplanin resistance was not observed in MRSA and MSSA. While against ciprofloxacin, levofloxacin, clindamycin, gentamicin decreased in both CA-MRSA and HA-MRSA. A closer follow-up of the prevalence and antimicrobial resistance profiles of these strains is of utmost importance for the successful control of the infections caused by MRSA and MSSA.

Group B Streptococcus serotypes associated with different clinical syndromes: Asymptomatic carriage in pregnant women, intrauterine fetal death, and early onset disease in the newborn.

ObjectivesTo study Group B Streptococcus (GBS) isolates associated with different clinical syndromes: asymptomatic carriage in pregnant women, intrauterine fetal death (IUFD), and early onset disease (EOD) in the newborn.MethodsGBS isolates were collected from asymptomatic pregnant women admitted for labor, IUFD cases, and neonates with EOD. Serotypes and antibiotic susceptibilities were determined. Multilocus sequence typing (MLST) was performed to assess genetic epidemiology.ResultsGBS carriage rate was 26.1% (280/1074). The dominant serotype among asymptomatic pregnant women was VI [98/240 women (40.8%)], followed by serotypes III, V and IV in 42/240 (17.5%), 30/240 (12.5%) and 28/240 (11.7%) women, respectively. The dominant serotype in IUFD cases was serotype VI [10/13 (76.9%)]. In contrast the prevalent serotype among EOD cases was III [16/19 (84.2%)]. ST-1 was associated with IUFD [7/13 (53.8%)], ST-17 was associated with serotype III and EOD in the newborn 14/19 (73.7%)]. Erythromycin and clindamycin resistance reached 36.8%, 7.7% and 20.0%among EOD, vaginal carriage and IUFD, respectively.ConclusionsSerotypes VI and ST-1 were dominant among asymptomatic pregnant women and in IUFD cases while EOD was associated with serotype III and ST-17. Invasive mechanisms thus may differ between IUFD and EOD in the newborn and virulence may be related to capsule serotype. Resistance rates to erythromycin and clindamycin were high in EOD cases.

Resistance of Streptococcus pneumoniae Strains Isolated from Clinical Samples to Various Antibiotics

Objective: It was aimed to determine the antibiotics resistance rates of Streptococcus pneumoniae (S. pneumoniae) strains which are important causes of mortality and morbidity with increasing resistance rates.&#x0D; Methods: Antibiotic susceptibilities of 80 S. pneumoniae specimens identified from samples sent from various clinics in our hospital were analyzed retrospectively. Isolated strains were identified by classical methods and BD Phoenix 100 system (Becton Dickinson Diagnostic, USA) and their antimicrobial susceptibility was evaluated by Kirby-Bauer disc diffusion method according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) document. Penicillin, cefotaxime and meropenem susceptibilities were examined by gradient test; while erythromycin, clindamycin, trimethoprim-sulfamethoxazole, levofloxacin, tetracycline, vancomycin and linezolid resistances were analyzed by disc diffusion method.&#x0D; Results: A total of 80 isolates including 32 blood samples, 29 respiratory samples, 10 cerebrospinal fluid (CSF), 5 vitreous, 3 pleural fluid and 1 abscess aspiration were included in the study. Penicillin resistance in CSF isolates was 70% and there was no resistance to cefotaxime and meropenem. Of 70 non-CSF isolates, 15 (21.4%) were moderately resistant, 14 (20%) were highly resistant and 41 (58.6%) were susceptible to penicillin. Cefotaxime resistance was detected in 2 (2.9%) of these isolates. Intermediate values were found in 2 (2.9%) isolates and remaining 66 (94.2%) isolates were susceptible to cefotaxime. There was no meropenem resistance in non-CSF isolates. Resistance rates of erythromycin, clindamycin, trimethoprim-sulfamethoxazole, levofloxacin and tetracycline in all isolates were 32.5%, 27.5%, 42.5%, 3.7% ve 30% respectively. There was no resistance to vancomycin and linezolid.&#x0D; Conclusion: Penicillin resistance is high in S. pneumoniae strains and penicillin has no place in empirical treatment of pneumococcal meningitis. Periodic monitoring of infectious agents and antibiotic susceptibilities in certain regions may guide clinicians to initiate empirical treatment.

Research Note: Antimicrobial resistance of Campylobacter species isolated from chickens near Ulaanbaatar city, Mongolia

There has been no report on the prevalence of Campylobacter spp. in farm animals in Mongolia. To uncover the prevalence of Campylobacter spp. in chickens in Mongolia and their antimicrobial resistance, in this study, we isolated and characterized Campylobacter spp. from chickens in Mongolia. We collected 71 cloacal swabs of chickens from 5 farms including 4 layer farms and one broiler farm near Ulaanbaatar city and isolated 25 Campylobacter jejuni and 6 Campylobacter coli isolates. All isolates were resistant to tetracycline, and 3 C. coli isolates were resistant to erythromycin. The C. coli isolates possessed either the erm(B) gene or nucleotide substitution at nt 2,075 of 23S rDNA, both of which are known to be associated with erythromycin resistance. Sixteen of the 31 C. jejuni/C. coli isolates (51.6%) were resistant to nalidixic acid and fluoroquinolones. All the fluoroquinolone-resistant isolates possessed amino acid substitution from threonine to isoleucine at codon 86 (nucleotide substitution: ACA to ATA). Multilocus sequence typing and phylogenetic analyses showed a variation in C. jejuni/C. coli in chickens in Mongolia. In addition, some of the C. jejuni isolates seemed to be phylogenetically close to isolates in Asian and Oceanian countries. This is the first report on the characterization of antimicrobial resistance of Campylobacter spp. in farm animals in Mongolia and is valuable for implementation of measures for a prudent use of antimicrobials in farm animals.

Shared requirements for key residues in the antibiotic resistance enzymes ErmC and ErmE suggest a common mode of RNA recognition

Erythromycin-resistance methyltransferases are SAM dependent Rossmann fold methyltransferases that convert A2058 of 23S rRNA to m62A2058. This modification sterically blocks binding of several classes of antibiotics to 23S rRNA, resulting in a multidrug-resistant phenotype in bacteria expressing the enzyme. ErmC is an erythromycin resistance methyltransferase found in many Gram-positive pathogens, whereas ErmE is found in the soil bacterium that biosynthesizes erythromycin. Whether ErmC and ErmE, which possess only 24% sequence identity, use similar structural elements for rRNA substrate recognition and positioning is not known. To investigate this question, we used structural data from related proteins to guide site-saturation mutagenesis of key residues and characterized selected variants by antibiotic susceptibility testing, single turnover kinetics, and RNA affinity-binding assays. We demonstrate that residues in α4, α5, and the α5-α6 linker are essential for methyltransferase function, including an aromatic residue on α4 that likely forms stacking interactions with the substrate adenosine and basic residues in α5 and the α5-α6 linker that likely mediate conformational rearrangements in the protein and cognate rRNA upon interaction. The functional studies led us to a new structural model for the ErmC or ErmE-rRNA complex.

Inducible clindamycin resistance in clinical isolates of staphylococcus aureus in Suez Canal University Hospital, Ismailia, Egypt.

The increasing incidence of methicillin resistance among Staphylococci has led to renewed interest in the usage of macrolide-lincosamide-streptogramin B (MLSB) antibiotics to treat S. aureus infections, with clindamycin being the preferable agent owing to its excellent pharmacokinetic properties. Inducible clindamycin resistance my lead to therapeutic failure. Detection of the prevalence of constitutive and inducible clindamycin resistance in clinical isolates of S. aureus to improve the clinical outcomes in patients. A total of 176 non-duplicate staphylococcal isolates were isolated from different clinical samples. Methicillin resistance was detected using Cefoxitin disk diffusion (CDD) method. Phenotypic clindamycin resistance was performed for all isolates by D test. Polymerase Chain Reaction (PCR) assay were done for detection of erm resistance genes (ermA, ermB and ermC). Out of 176 strains of S. aureus, 108 isolates (61.3%) were identified as MRSA. Erythromycin and clindamycin resistance was detected in 96 isolates (54.5%) and 68 isolates (38.6%) respectively. Clindamycin resistance (cMLSB) was significantly higher (p value < 0.001) in MRSA strains (56 isolates) compared to MSSA (12 isolates). Resistant genes were detected in 160 isolates (91%). The ermA gene was detected in 28 isolates (16%), the ermB gene was detected in 80 isolates (45.5%) (p < 0.001). The frequency of constitutive and inducible clindamycin resistance in MRSA isolates emphasizes the need to use D test in routine antimicrobial susceptibility testing to detect the susceptibility to clindamycin as the inducible resistance phenotype can inhibit the action of clindamycin and affect the treatment efficacy.

A Possible Role of Insertion Sequence IS1216V in Dissemination of Multidrug-Resistant Elements MESPM1 and MES6272-2 between Enterococcus and ST59 Staphylococcus aureus.

Sequence type 59 (ST59) is the dominant type of community-associated methicillin-resistant Staphylococcus aureus (MRSA) in Taiwan. Previously, we reported that ST59 MRSA harbors enterococcal IS1216V-mediated multidrug-resistant composite transposons MESPM1 or MES6272-2. The MES were found to have a mosaic structure, largely originating in enterococci and partly native to S. aureus. The current study aimed to track the origin of the MES and how they disseminated from enterococci to ST59 S. aureus. A total of 270 enterococcal isolates were analyzed, showing that two ST64 Enterococcus faecalis isolated in 1992 and 11 clonal complex 17 Enterococcus faecium harbored MESPM1-like and MES6272-2-like structures, respectively. Sequence analysis revealed that ST64 E. faecalis strain N48 acquired the MESPM1-like structure on the plasmid pEflis48. The pEflis48 harbored the enterococci-originated region (erythromycin, kanamycin, and streptomycin resistances) and the S. aureus-originated region (chloramphenicol resistance) of MESPM1 but was separated by the replication region of the plasmid. Homologous recombination between the two direct repeats of IS1216V resulted in excision of the replication region of the plasmid to regenerate MESPM1. The p4780-1 and pV19 of E. faecium carried MES6272-2-like structures with IS1216V, albeit with multiple insertions by other insertion sequences. The findings show that IS1216V plays important roles in bidirectional gene transfer of multidrug resistance between enterococci and S. aureus.

Erythromycin Resistance in Bacterial Isolates from Patients with Respiratory Tract Infections in Ikere-Ekiti, Nigeria

Abstract The occurrence of erythromycin resistance in bacteria causing respiratory tract infections varies among populations and is associated with inappropriate antibiotic usage. This study was undertaken to determine erythromycin resistance in bacterial isolates from patients with respiratory tract infections in Ikere-Ekiti. Bacteria were isolated from sputum specimens using standard microbiological protocols while the antibiotic susceptibility pattern of isolates was determined using the Kirby-Bauer method. Erythromycin resistance genes: mefA, ermA, and ermB were detected using multiplex polymerase chain reaction (PCR). Out of the 157 bacterial isolates identified using standard microbiological methods, Klebsiella spp. 40 (25%) was the most frequent followed by Staphylococcus aureus 34 (22%) and Proteus spp. 34 (22%) while Streptococcus spp., Escherichia coli, and Bacillus spp. had 19 (12%), 20 (13%), and 10 (6%) respectively. Most of the bacterial isolates were resistant to penicillin 148 (94%), cloxacillin 147 (93.6%), amoxicillin-clavulanic acid 141 (90%), erythromycin 141 (90%), and tetracycline 124 (79%). However, the isolates were least resistant to trimethoprim-sulfamethoxazole 57 (36%). Out of the 48 bacterial isolates investigated using multiplex PCR amplification for erythromycin resistance genes, 10 (20.8%) were positive for mefA, 3 (6.3%) were positive for ermA, and 2 (4.2%) were positive for ermB. The association between the presence of mefA, ermA, and ermB genes and erythromycin resistance was not significant (p=0.464). The presence of erythromycin resistant genes in pathogenic bacterial isolates from the respiratory tract was revealed in this study. Awareness of the risk of self-medication and abuse of antibiotics should be emphasized.

Toxinotyping and molecular characterization of antimicrobial resistance in Clostridium perfringens isolated from different sources of livestock and poultry

The present study was designed to understand the presence of antimicrobial resistance among the prevalent toxinotypes of Clostridium perfringens recovered from different animals of Tamil Nadu, India. A total of 75 (10.76%) C. perfringens were isolated from 697 multi-species fecal and intestinal content samples. C. perfringens type A (90.67%), type C (2.67%), type D (4%) and type F (2.67%) were recovered. Maximum number of isolates were recovered from dog (n = 20, 24.10%) followed by chicken (n = 19, 5.88%). Recovered isolates were resistant to gentamicin (44.00%), erythromycin (40.00%), bacitracin (40.00%), and tetracycline (26.67%), phenotypically and most of the isolates were found to be resistant to multiple antimicrobials. Genotypic characterization revealed that tetracycline (41.33%), erythromycin (34.66%) and bacitracin (17.33%) resistant genes were present individually or in combination among the isolates. Combined results of phenotypic and genotypic characterization showed the highest percentage of erythromycin resistance (26.66%) among the isolates. None of the isolates showed amplification for lincomycin resistance genes. The correlation matrix analysis of genotypic resistance showed a weak positive relationship between the tetracycline and bacitracin resistance while a weak negative relationship between the tetracycline and erythromycin resistance. The present study thus reports the presence of multiple-resistance genes among C. perfringens isolates that may be involved in the dissemination of resistance to other bacteria present across species. Further insights into the genome can help to understand the mechanism involved in gene transfer so that measures can be taken to prevent the AMR spread.

Comparative Assessment of Antibiotic Resistance in Lactic Acid Bacteria Isolated from Healthy Human Adult and Infant Feces

Lactic acid bacteria are normal inhabitants of the gastrointestinal tract of humans. Their occurrence in infant and adult feces is abundant. The current study assesses and compares the antibiotic resistance in lactic acid bacteria isolated from healthy human adult and healthy infant fecal samples. A total of 255 lactic acid bacteria isolates (126 from adult feces and 129 from infant feces) were isolated and characterized from 60 fecal samples. Lactobacillus spp., Pediococcus spp. and Enterococcus spp. were included in the study. The study was done using the WHONET software for the analysis of antibiotic susceptibility data of lactic acid bacteria. Most of the Lactobacillus and Pediococcus strains were sensitive to vancomycin. Enterococcus strains showed resistance against vancomycin. Ampicillin, ciprofloxacin and cefuroxime resistance were significantly (p&lt;0.05) higher in Lactobacillus strains isolated from adult fecal samples than those isolated from infant fecal samples. A similar pattern was observed in Enterococcus strains with erythromycin, gentamycin and tobramycin resistance. Pediococcal isolates from adult feces showed significantly higher resistance against tobramycin, ciprofloxacin, gentamycin, cefotaxime and cefuroxime in comparison with infant fecal isolates. Antibiotic resistance was exhibited by lactic acid bacteria against most commonly used antibiotics and it was higher in strains isolated from adult fecal samples than in the strains isolated from infant fecal samples. The increasing trend in antibiotic resistance from infant to adult might be due to food habits and antibiotic intakes. Thus, the widespread antibiotic resistance in different lactic acid bacteriamay pose a food safety concern as well.

Early Inoculation of Microbial Suspension in Suckling Piglets Affects the Transmission of Maternal Microbiota and the Associated Antibiotic Resistance Genes.

Antibiotic resistance of microbes thriving in the animal gut is a growing concern for public health as it may serve as a hidden reservoir for antibiotic resistance genes (ARGs). We compared 16 control piglets to 24 piglets fed for 3 weeks with S1 or S2 fecal suspensions from two sows that were not exposed to antibiotics for at least 6 months: the first suspension decreased the erythromycin resistance gene ermB and the aminoglycoside phosphotransferase gene conferring resistance to kanamycine (aphA3), while the second decreased the tetracycline resistance gene tetL, with an unexpected increase in ARGs. Using 16S RNA sequencing, we identified microbial species that are likely to carry ARGs, such as the lincosamide nucleotidyltransferase lnuB, the cephalosporinase cepA, and the tetracycline resistance genes tetG and tetM, as well as microbes that never co-exist with the tetracycline resistance gene tetQ, the erythromycin resistance gene ermG and aphA3. Since 73% of the microbes detected in the sows were not detected in the piglets at weaning, a neutral model was applied to estimate whether a microbial species is more important than chance would predict. This model confirmed that force-feeding modifies the dynamics of gut colonization. In conclusion, early inoculation of gut microbes is an interesting possibility to stimulate gut microbiota towards a desirable state in pig production, but more work is needed to be able to predict which communities should be used.

Antimicrobial Resistance and Biofilm Formation by Staphylococcus aureus Isolated From Ocular Infections

Background: Untreated staphylococcal ocular infections may cause injuries in the ocular structure and lead to visual impairments, lesions in the anatomical ocular surface, and blindness. The aim of the study was to describe the characteristic of 90 Staphylococcus aureus (SA) strains from hospital and community treated ocular infections with a special emphasis on ability of biofilm formation and drug resistance. The biofilm formation was carried out using the Congo red agar (CRA) method applying Congo red dye. Studies have demonstrated that the CRA method is simple, fast, and repeatable and that modifications of some components can easily increase its accuracy. Methods: Biofilm formation was examined by the method with CRA test. On CRA, slime-producing strains formed black colonies, whereas nonproducing strains developed red colonies in 6 kinds of colors, from very red to very black: very red, red, burgundy, almost black, black, and very black. Antimicrobial susceptibility testing was performed by disc diffusion or the E-test method according to the current guidelines of the EUCAST. The MRSA, and MLSB phenotypes were detected. Polymerase chain reaction (PCR) was used to detect the mecA, and mupA genes. Erythromycin resistance genes (ermA, ermB, ermC, and msr) were detected by multiplex PCR. Results: A positive result of the CRA test was accomplished in 66.2% cases; significantly more often in hospital strains (73.4% vs 45.4%; OR, 3.3; 55% CI, 1.2–9.3). Moreover, 73.4% isolates were fully susceptible. In hospitalized patients, the level of resistance to at least 1 antimicrobial category has been identified as 40.9%, and this rate was 27.2% in outpatients. Among the tested strains, 5 (6.0%) had the resistance phenotype MRSA and 22 (26.5%) the resistance phenotype MLSB; 4 strains manifested both mechanisms; erythromycin resistance was 25.3% in those resistant to fluoroquinolones. Resistance to fluoroquinolones was 5 times more often found in ambulatory patients. All of the tested isolates were vancomycin sensitive. Conclusions: Biofilm formation is an important risk factor for developmental staphylococcal hospital-acquired ocular infections. Our results prove that hospital strains have demonstrated much greater biofilm-forming ability than nonhospital strains. Studies indicate the high efficacy of chloramphenicol and fluoroquinolones treatments, as well as the need to implement new solutions due to the aforementioned bacteria’s high resistance to neomycin and anatomic barriers difficulties.Disclosures: NoneFunding: None

Effects of Glycerol and Shikimic Acid on Rapamycin Production in Streptomyces rapamycinicus

Rapamycin, derived from Streptomyces rapamycinicus, is an important bioactive compound having a therapeutic value in managing Parkinson’s disease, rheumatoid arthritis, cancer, and AIDS. Because of its pharmaceutical activity, studies over the past decade have focused on the biosynthesis of rapamycin to enhance its yield. In this study, the effect of rapG on rapamycin production was investigated. The rapG expression vector was constructed by utilizing the integration vector pSET152 under the control of the erythromycin resistance gene (ermE*), a strong constitutive promoter. The rapamycin yield of wild type (WT) and WT/ rapG overexpression mutant strains, under fermentation conditions, was analyzed by high-performance liquid chromatography (HPLC). Our results revealed that overexpression of rapG increased rapamycin production by approximately 4.9-fold (211.4 mg/l) in MD1 containing 15 g/l of glycerol, compared to that of the WT strain. It was also found that Illicium verum powder (10 g/l), containing shikimic acid, enhanced rapamycin production in both WT and WT/rapG strains. Moreover, the amount of rapamycin produced by the WT/rapG strain was statistically higher than that produced by the WT strain. In conclusion, the addition 15 g/l glycerol and 15 g/l I. verum powder produced the optimal conditions for rapamycin production by WT and WT/rapG strains.

Spectrum and resistance determinants of oral streptococci clinical isolates.

The profiles of oral streptococci sensitivity to antibacterial drugs may reflect information about the presence of macroorganism resistance determinants. The aim of the work was to isolate the spectrum of oral streptococci from the microbiota of the oral cavity of patients and to determine their sensitivity to a wide range of antibiotics. A total of 342 microbial streptococcal isolates were isolated from saliva samples and a periodontal pocket and tested for antibiotic sensitivity. Species identification of streptococci was carried out using biochemical API test systems. Evaluation of antibiotic resistance was performed using E-tests. Real-time PCR was used to identify the presence of tetracycline and macrolide resistance genes. The study identified six types of oral streptococci: S. oralis, S. salivarius, S. mitis, S. sanguinis, S. anginosus and S. mutans. All streptococci were sensitive to linezolid and meropenem. The proportion of penicillin-resistant streptococci in the subgroup S. oralis / mitis / mutans was 47,8% versus 23,5% in the subgroup S. salivarius / sanguinis / anginosus (p = 0.020). Significant levels of resistance were revealed to macrolides (erythromycin) - 47,9%, tetracyclines (tetracycline) - 44,4% and quinolones (ofloxacin) - 41%. Multiple drug resistance (MDR) was detected in 31,9% of oral streptococcal isolates, a combination of erythromycin, tetracycline and ofloxacin resistance was prevalent in 79 isolates (23,1%). The most common genotypes of macrolides and tetracycline resistant oral streptococci (in 127 streptococcal isolates with combined resistance) were ermB-mefE + and tetM + tetQ-, respectively. Thus, S. oralis / mitis / mutans group streptococci predominated in the structure of antibiotic-resistant oral streptococci, including MDR. So, being in one of the most densely populated biotopes of a macroorganism, oral streptococci can mediate the transfer of resistance determinants to more pathogenic and clinically significant microorganisms, which requires careful monitoring of their level of susceptibility to antimicrobial agents.