Investigation of SCCmec types I-IV in clinical isolates of methicillin-resistant coagulase-negative staphylococci in Ahvaz, Southwest Iran

The pathogenicity and virulence of the opportunistic pathogen Staphylococcus epidermidis

The pervasive presence of Staphylococcus epidermidis and other coagulase-negative staphylococci on the skin and mucous membranes has long underpinned a casual disregard for the infection risk that these organisms pose to vulnerable patients in healthcare settings. Prior to the recognition of biofilm as an important virulence determinant in S. epidermidis, isolation of this microorganism in diagnostic specimens was often overlooked as clinically insignificant with potential delays in diagnosis and onset of appropriate treatment, contributing to the establishment of chronic infection and increased morbidity or mortality. While impressive progress has been made in our understanding of biofilm mechanisms in this important opportunistic pathogen, research into other virulence determinants has lagged S. aureus. In this review, the broader virulence potential of S. epidermidis including biofilm, toxins, proteases, immune evasion strategies and antibiotic resistance mechanisms is surveyed, together with current and future approaches for improved therapeutic interventions.

Staphylococcus capitis Bloodstream Isolates: Investigation of Clonal Relationship, Resistance Profile, Virulence and Biofilm Formation

Staphylococcus capitis has been recognized as a relevant opportunistic pathogen, particularly its persistence in neonatal ICUs around the world. Therefore, the aim of this study was to describe the epidemiological profile of clinical isolates of S. capitis and to characterize the factors involved in the persistence and pathogenesis of these strains isolated from blood cultures collected in a hospital in the interior of the state of São Paulo, Brazil. A total of 141 S. capitis strains were submitted to detection of the mecA gene and SCCmec typing by multiplex PCR. Genes involved in biofilm production and genes encoding enterotoxins and hemolysins were detected by conventional PCR. Biofilm formation was evaluated by the polystyrene plate adherence test and phenotypic resistance was investigated by the disk diffusion method. Finally, pulsed-field gel electrophoresis (PFGE) was used to analyze the clonal relationship between isolates. The mecA gene was detected in 99 (70.2%) isolates, with this percentage reaching 100% in the neonatal ICU. SCCmec type III was the most prevalent type, detected in 31 (31.3%) isolates and co-occurrence of SCCmec was also observed. In vitro biofilm formation was detected in 46 (32.6%) isolates but was not correlated with the presence of the ica operon genes. Furthermore, biofilm production in ICU isolates was favored by hyperosmotic conditions, which are common in ICUs because of the frequent parenteral nutrition. Analysis of the clonal relationship between the isolates investigated in the present study confirms a homogeneous profile of S. capitis and the persistence of clones that are prevalent in the neonatal ICU and disseminated across the hospital. This study highlights the adaptation of isolates to specific hospital environments and their high clonality.

Molecular identification and biofilm formation of aerobic and anaerobic coinfection bacterial isolated from cystic fibrosis patients in southwest Iran from 2014 to 2022

BACKGROUND

Coinfections and resistant bacterial infections are more likely to occur in cystic fibrosis patients because their immune systems are weak. The purpose of this study was to identify by molecular means as well as the formation of biofilm of aerobic and anaerobic coinfection bacteria isolated from cystic fibrosis patients in southwest Iran from 2014 to 2022.

METHODS

In this investigation, 130 clinical specimens were collected from 130 CF patients by universal primer. Biofilm formation was investigated using the microtiter plate method. Antibiotic resistance was measured using Vitec 2 device. In addition, identification of methicillin-resistant Staphylococcus aureus using genes mecA was performed.

MAIN FINDINGS

In aerobic bacteria, Pseudomonas aeruginosa was detected in (32%) of samples. In anaerobic bacteria (16%) Prevotella spp. was the most frequently isolated anaerobe bacteria found in of the CF patients. In this study, 75% of the bacteria could form biofilms, while 23% were unable to biofilm formation.

CONCLUSION

In conclusion, P. aeruginosa was found to be the most frequently isolated bacterium from patients with CF, and many of these bacteria could form biofilms. Additionally, the high prevalence of antibiotic resistance indicates the urgent need for increased attention to antibiotic preparation and patient screening concerning bacterial coinfections and the virulence and adhesion factors of these bacteria. Furthermore, the present study demonstrates that the coinfection of bacteria with high antibiotic resistance and a high capacity for biofilm formation can pose a life-threatening risk to CF patients, mainly due to their weakened immune systems.

Identification and characterization of SCCmec typing with psm-mec positivity in staphylococci from patients with coagulase-negative staphylococci peritoneal dialysis-related peritonitis

BACKGROUND

Peritonitis is the most important complication of peritoneal dialysis (PD) and coagulase-negative staphylococci (CNS) are a frequent cause of dialysis-related infections. The association between SCCmec typing with psm-mec positivity in staphylococci and PD-related infections has not been identified. We aim to investigate the molecular epidemiology of CNS isolated from PD-peritonitis in a single Chinese center, focusing on the genetic determinants conferring methicillin resistance.

METHODS

We collected 10 genetically unrelated CNS isolates from 10 patients with CNS PD-related peritonitis. The patients were divided into two groups based on the results of MIC to oxacillin: the methicillin-resistant CNS (MRCNS) and methicillin-sensitive CNS (MSCNS) groups. The biofilm formation group (BFG) and the non-biofilm formation group (NBFG) were used as the control groups. Phenotypic and molecular methods were used to analyze SCCmec types I, II and III, associated genes and biofilm formation and the existence of psm-mec. The demographic data and clinical indicators were collected.

RESULTS

Ten CNS PD-related peritonitis patients were enrolled for this study. There were 6 MRCNS and 4 MRCNS isolates. SCCmec types were fully determined in 10 isolates. Seven staphylococci (70%) carried SCCmec, of which 4 isolates carried single SCCmec type I (40%) and 3 isolates had multiple SCCmec elements (I + III). Of the 6 MRCNS isolates, 3 carried SCCmec type I (50%) and 2 isolates carried SCCmec type I + III (33.3%). A high diversity of ccr types, mec complexes and ccr-mec complex combinations was identified among the 10 CNS isolates. The psm-mec gene was detected in 2/10 (20%) CNS isolates. There was no mutation in the psm-mec gene.

CONCLUSIONS

The majority of isolates were hospital-associated isolates. Furthermore, 2 psm-mec positive isolates were MRCNS in the NBFG. The PD patients frequent exposure to hospital would be the main risk factor. The presence of the psm-mec signal in the spectra of the MRCNS tested here demonstrates the presence of certain SCCmec cassettes that convey methicillin resistance.

Study of the antibacterial effects of the starch-based zinc oxide nanoparticles on methicillin resistance Staphylococcus aureus isolates from different clinical specimens of patients from Basrah, Iraq

This study aimed to assess the efficacy of starch-based zinc oxide nanoparticles (ZnO-NPs) against methicillin-resistant Staphylococcus aureus (MRSA) isolates from clinical specimens in Basrah, Iraq. In this cross-sectional study, 61 MRSA were collected from different clinical specimens of patients in Basrah city, Iraq. MRSA isolates were identified using standard microbiology tests, cefoxitin disc diffusion and oxacillin salt agar. ZnO-NPs were synthesized in three different concentrations (0.1 M, 0.05 M, 0.02 M) by the chemical method using starch as the stabilizer. Starch-based ZnO-NPs were characterized using ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The antibacterial effects of particles were investigated by the disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the most effective starch-based ZnO-NPs were determined using a broth microdilution assay. The UV-Vis of all concentrations of starch-based ZnO-NPs exhibited a strong absorption band at 360 nm which was characteristic of the ZnO-NPs. XRD assay confirmed the representative hexagonal wurtzite phase of the starch-based ZnO-NPs, and their purity and high crystallinity. The spherical shape with a diameter of 21.56 ± 3.42 and 22.87 ± 3.91 was revealed for the particles by FE-SEM and TEM, respectively. EDS analysis confirmed the presence of zinc (Zn) (61.4 ± 0.54%) and oxygen (O) (36 ± 0.14%). The 0.1 M concentration had the highest antibacterial effects (mean ± SD of inhibition zone = 17.62 ± 2.65 mm) followed by the 0.05 M concentration (16.03 ± 2.24 mm) and the 0.02 M concentration (12.7 ± 2.57 mm). The MIC and the MBC of the 0.1 M concentration were in the range of 25-50 µg/mL and 50-100 µg/mL, respectively. Infections caused by MRSA can be treated with biopolymer-based ZnO-NPs as effective antimicrobials.

Loop mediated isothermal amplification of Clostridioides difficile isolates in gastrointestinal patients

This study investigated the prevalence of Clostridioides difficile by culture, multiplex polymerase chain reaction (M-PCR), and loop mediated isothermal amplification (LAMP) in patients with suspected C. difficile infections (CDIs). Also, the results of three methods were compared. All stool specimens collected from CDI suspected patients were cultured on selective C. difficile cycloserine-cefoxitin fructose agar and incubated in an anaerobic jar up to 7 days. The bacterial isolates were identified using standard tests. Multiplex-PCR (M-PCR) was performed for detection of tcdA, tcdB, and tpi genes. The LAMP assay was performed to detect the tcdB gene of C. difficile. C. difficile was isolated from 20.0% (n = 10/50) of samples by culture. M-PCR showed that 34.0% (n = 17/50) of the specimens were positive for C. difficile based on the presence of tpi gene. Out of the 17 C. difficile, 13 strains (76.0%) were positive for tcdB gene using M-PCR. However, the LAMP assay showed that 30.0% (15/50) of specimens were positive for the presence of tcdB gene. M-PCR and LAMP methods showed 100.0% sensitivity compared to the culture method. However, the specificity of the LAMP (87.5%) was relatively higher than the M-PCR (82.5%) compared to the culture. Based on the results of this study, the prevalence of toxigenic C. difficile strains was high in suspected CDI patients. So, the differentiation between toxigenic and non-toxigenic strains is necessary. Our data showed that the LAMP assay is a good method for direct detection of toxigenic C. difficile strains from stool specimens.

Detection of partial and/or complete Y chromosome microdeletions of azoospermia factor a (AZFa) sub-region in infertile Iraqi patients with azoospermia and severe oligozoospermia

BACKGROUND

This study aimed to analyze the incidence of azoospermia factor a (AZFa) microdeletions in the Y chromosome and their association with male infertility in a population with azoospermia and severe oligozoospermia from Iraq.

METHODS

A total of 75 infertile Iraqi males and 25 healthy controls were included in this study. The semen analysis was performed to determine the azoospermia, severe oligozoospermia, or normal cases. The AZFa microdeletions were investigated using the real-time polymerase chain reaction (real-time PCR). Then, AZFa sub-region deletions were investigated by a conventional PCR.

RESULTS

In total, 40 men with azoospermia and 35 men with severe oligozoospermia were selected. Out of 75 infertile males, 46 (61.3%) individuals had AZFa microdeletions, of whom 32 (69.6%) had partial deletion, while 14 (30.4%) males had complete deletion using real-time PCR. The frequency of microdeletions was significantly different between the infertile and control group (p-value < 0.00001). The proportion of AZFa microdeletions appeared higher in azoospermia men (72.5%, n = 29/40) than severe oligozoospermia men (48.6%, n = 17/35), but based on the conventional PCR results, only one azoospermia patient (2.2%) was shown to have complete AZFa deletion, while the other 45 patients (97.8%) had partial AZFa deletions.

CONCLUSION

In this study, the partial AZFa microdeletions were more numerous than complete AZFa deletion. According to our results, the AZFa microdeletions might be associated with male infertility and spermatogenic failure. It is recommended to investigate the AZFa sub-region microdeletions in patients that shown AZFa microdeletions in primary screening.

Identification and detection of pathogenic bacteria from patients with hospital-acquired pneumonia in southwestern Iran; evaluation of biofilm production and molecular typing of bacterial isolates

Background

Hospital-acquired pneumonia (HAP) is the second most common nosocomial infection in intensive care units (ICUs). The present study aims to determine the prevalence of pathogenic bacteria, their biofilm formation, and molecular typing from patients with HAP in southwestern Iran.

Methods

Fifty-eight patients with HAP participated in this cross-sectional study. Sputum and endotracheal aspirate were collected from each patient for isolation and detection of bacteria. Biofilm formation was evaluated using Congo red agar or Microtiter plate assay. The antimicrobial susceptibility patterns of the isolates were investigated. The multiplex polymerase chain reaction (M-PCR) technique was used to determine the Staphylococcal Cassette Chromosome mec (SCCmec) types of methicillin-resistant Staphylococcus aureus (MRSA) strains. All S. aureus isolates were typed using the agr typing method. A repetitive element sequence-based PCR (rep-PCR) typing method was used for typing of Gram-negative bacteria. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) software version 15 and the chi-square test.

Results

Bacteria were isolated in 52 (89.7%) of patients. Acinetobacter baumannii (A. baumannii) was the most prevalent organism (37%), followed by S. aureus, Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli). Using the PCR method, 56 bacteria were detected. A. baumannii was the most prevalent (35.7%) organism. A. baumannii and P. aeruginosa were biofilm-producing. All Gram-negative isolates were colistin-sensitive, and most of the A. baumannii isolates were multidrug-resistant (MDR). MRSA was identified in 12 (80%) S. aureus isolates, and 91.6% of MRSA were SCCmec type III. The agr type III was the most predominant. The rep-PCR analysis showed seven different patterns in 20 A. baumannii, six patterns in 13 P. aeruginosa, and four patterns in 6 E. coli.

Conclusion

A. baumannii was more prevalent than S. aureus in ventilator-associated pneumonia (VAP), while S. aureus is a major pathogen in non-ventilator hospital-acquired pneumonia (NV-HAP), possibly due to the tendency of the former to aquatic environments. Based on the rep-PCR typing method, it was concluded that bacteria were transmitted from patients or healthcare workers among different wards. Colistin can be used as a treatment in Gram-negative MDR isolates.

Oxacillin (Methicillin) Resistant Staphylococci in Domestic Animals in the Czech Republic

The aim of this study was to describe the prevalence of different Staphylococcus species isolated from pathological processes and lesions in domestic animals in the Czech Republic and to detect and describe oxacillin (methicillin)-resistant strains (MRS). During the years 2019–2020, a total of 5218 veterinary clinical samples from the Czech Republic were tested. Testing was performed by culture methods and typing by molecular phenotypic methods MALDI-TOF MS and PCR. Antimicrobial susceptibility testing of the strains was performed by the disk diffusion method. A total of 854 staphylococci strains were identified (16.37% prevalence), out of which 43 strains of 6 species of staphylococci were MRS (n = 43; 0.82% prevalence). Of the MRS strains, the most prevalent species were Staphylococcus pseudintermedius (n = 24; 0.46% prevalence) and Staphylococcus aureus (n = 7; 0.13% prevalence). Susceptibility testing showed resistance to beta-lactam antibiotics and, depending on the species, also to trimethoprim/sulfamethoxazole, gentamicin, tetracycline, erythromycin, clindamycin, and enrofloxacin. For further characterization of MRS, PCR assay for virulence factor genes was performed. Seven of the 14 target genes were observed only in S. aureus, except for the eno gene encoding laminin-binding protein, which was also detected in other staphylococci. It is necessary to emphasize the issue of correct using of antimicrobials in practice and antibiotic policy in university teaching and to create stricter legislation that would prevent the widespread use of antimicrobials in veterinary medicine, especially in livestock to reduce the emergence and spread of antimicrobial resistance.

Study of aerobic and anaerobic bacterial profile of nosocomial infections and their antibiotic resistance in a referral center, Southwest Iran: A three year cross-sectional study

BACKGROUND

The drug resistance is expected to be the most important challenge in infection control in Iran, where there is no local report or standard drug resistance monitoring system. Therefore, this study aimed to investigate the aerobic and anaerobic bacterial profile of nosocomial infections and their antibiotic resistance in Ahvaz, southwest Iran.

METHODOLOGY

The gram-positive and gram-negative bacteria were identified on the basis of conventional culture and biochemical tests. The antibiotic resistance of the bacterial isolates against antibiotics was determined by the disk diffusion method.

RESULTS

Among total 1156 collected positive samples, E. coli and coagulase-negative staphylococci (CoNS) were the most frequent pathogenic gram negative bacteria (GNB) and gram positive bacteria (GPB) respectively. Drug susceptibility testing revealed that among GNB, P. aeruginosa was 100% resistant to amikacin, cefepime, ciprofloxacin and tetracycline. In the case of E. coli, the resistance rate was (98%) for trimethoprim sulfamethoxazole and cefepime. For GPB, S. aureus showed the highest resistance rates to amikacin (100%) and clindamycin (100%). In addition, CoNS strains showed a high level of resistance to doxycycline (100%), erythromycin (100%) and cefoxitin (97%). In Bacteroeides fragilis isolates, the highest resistance rate belonged to clindamycin (72%), and Clostridium perfringens strains showed high level of resistance to penicillin (46%).

CONCLUSION

The results highlighted that there are distinct factors leading to antimicrobial resistance in Ahvaz, southwest Iran. The primary contributors to the resistance development, include poor surveillance of drug-resistant infections, poor quality of available antibiotics, clinical misuse, and the ease of access to antibiotics. Moreover, similar factors such as self-medication and the lack of regulation on medication imports play a role in antibiotic resistance in the region.

Distribution and antibiotic-resistance of different Staphylococcus species identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) isolated from the oral cavity

BACKGROUND

The use of antibiotics in dentistry is associated with the emergence and spread of antibiotic-resistant microorganisms, including commensal staphylococci.

METHODS

A total of 367 oral samples were collected, from which staphylococci were isolated and identified by using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). The antibiotic susceptibility of the isolates was determined and molecular characteristics for methicillin-resistant staphylococci was performed.

RESULTS

A total of 103 coagulase-negative staphylococci (CoNS), among them S. warneri, S. haemolyticus, S. saprophyticus, S. pasteuri, S. epidermidis, S. hominis, S. xylosus, S. equorum, S. kloosii, S. succinus, S. cohnii, and S. simulans, were confirmed by MALDI-TOF. Resistance to most tested antibiotics was statistically higher in CoNS than in S. aureus isolates (P-value < 0.05). CoNS isolates showed high resistance to penicillin (S. saprophyticus 88.9%), erythromycin (S. haemolyticus 84.6%), fusidic acid (S. saprophyticus 77.8%), co-trimoxazole (S. epidermidis 71.4%), gentamicin (S. warneri 63.8%), and tetracycline (S. saprophyticus 55.6%). Multidrug resistance was largely observed, especially among S. haemolyticus and S. saprophyticus species. Methicillin-resistance in S. haemolyticus (38.5%), S. saprophyticus (22.2%) and S. aureus (13.5%) was associated with the presence of the mecA gene and SCCmec type IV or V.

CONCLUSION

Coagulase-negative staphylococci, especially S. haemolyticus and S. saprophyticus, seem to be a reservoir of methicillin resistance and multidrug resistance in the oral cavity.

Susceptibility to biocides and the prevalence of biocides resistance genes in clinical multidrug-resistant Pseudomonas aeruginosa isolates from Hamadan, Iran

BACKGROUND

This study aimed to investigate the association between biocides' reduced susceptibility and the presence of efflux pump genes including cepA, qacEΔ1 and qacE in multidrug-resistant (MDR) Pseudomonas aeruginosa.

METHODS AND RESULTS

The MDR P. aeruginosa isolates were collected and identified from different clinical samples. The minimum inhibitory concentrations (MIC) of four biocides (chlorhexidine gluconate 1%, benzalkonium chloride 1%, Kohrsolin® extra, and SEPTI-Turbo) were determined by microbroth dilution with and without carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Polymerase chain reaction (PCR) was performed for detecting the efflux pump genes. In total, 92 MDR P. aeruginosa isolates were collected. The reduced susceptibility (8-128 µg/ml) was seen against chlorhexidine gluconate 1%, benzalkonium chloride 1%, Kohrsolin® extra, and SEPTI-Turbo in 63 (68.5%), 59 (64.1%), 64 (69.6%), and 65 (70.6%) isolates, respectively. The Kohrsolin® extra was the most effective biocide. The cepA, qacE, and qacEΔ1 were detected in 56 (60.9%), 1 (1.1%), and 34 (36.9%) isolates, respectively. There was a significant association between the presence of biocide resistance genes and reduced susceptibility to studied biocides (P = 0.00001). The CCCP had no effect on benzalkonium chloride 1% and Kohrsolin® extra, but reduced the MICs of chlorhexidine gluconate 1% and SEPTI- Turbo by 2 to 128 fold.

CONCLUSIONS

The P. aeruginosa isolates exhibited varying degrees of tolerance to biocides. The cepA was the most prevalent gene. There was a significant connection between the occurrence of the efflux pump genes cepA and qacEΔ1 with reduced biocide susceptibility.

Prevalence of Antibiotic Resistance of ESKAPE Pathogens Over Five Years in an Infectious Diseases Hospital from South-East of Romania

PURPOSE

This study aimed at identifying the main antimicrobial resistance of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli) pathogens in a Romanian infectious diseases hospital. This antimicrobial resistance is a global threat, having high rates of multidrug resistance and limited treatment options.

PATIENTS AND METHODS

This retrospective study (2016-2020) assessed the antimicrobial resistance of ESKAPE pathogens isolated from the patient's biological samples. The microbiological diagnosis was performed by classical culture methods. The antimicrobial susceptibility analysis used the Kirby-Bauer disk-diffusion method and the method of minimum inhibiting concentration with the automated Vitek, according to the CLSI (Clinical and Laboratory Standards Institute) standards.

RESULTS

Included in this study were 4293 bacterial isolates: 67% Gram-negative bacilli, 31% Gram-positive cocci and 2% other morphotinctorial bacteria. ESKAPE pathogens were found in 97% of the bacterial isolates strains; E. coli (38.26%) and Staphylococcus aureus (26%) were the most prevalent. Most bacterial strains were isolated from urine cultures (45.6%), skin and soft tissue secretions/collections (35.9%) and also blood cultures (4.2%). Increased antimicrobial resistance was observed for methicillin-resistant Staphylococcus aureus (MRSA)s, extended spectrum beta-lactamase producing (ESBL) Enterobacterales, carbapenem-resistant (CR) Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. No vancomycin resistance was found for Enterococcus faecium. The highest prevalence rates of multidrug resistance were found in methicillin-resistant Staphylococcus aureus (86.6%), Acinetobacter baumannii (36.8%), Pseudomonas aeruginosa (29.1%) and Klebsiella pneumoniae (24.4%).

CONCLUSION

ESKAPE pathogens are frequently isolated in the infectious diseases hospital, with main antimicrobial resistance: ESBL, MRSA and CR. The local antimicrobial resistance pattern is essential in updating the local protocols and for appropriately prescribing antibiotics. Streamlining microbiological diagnosis and aligning with the European standards for antimicrobial susceptibility testing are necessary steps in harmonizing the regional network for good antimicrobial resistance control practices.

Occurrence of Multiple-Drug Resistance bacteria and their antimicrobial resistance patterns in burn infections from southwest of Iran

BACKGROUND

Burn infection continues to be a major issue of concern globally and causes more harm to developing countries. This study aimed to identify the aerobic bacteriological profiles and antimicrobial resistance patterns of burn infections in three hospitals in Abadan, southwest Iran.

METHODS

The cultures of various clinical samples obtained from 325 burn patients were investigated from January to December 2019. All bacterial isolates were identified based on the standard microbiological procedures. Antibiotic susceptibility tests were performed according to the CLSI.

RESULTS

A total of 287 bacterial species were isolated burn patients.P. aeruginosa was the most frequent bacterial isolate in Gram-negative bacteria and S. epidermidis was the most frequent species isolated in Gram-positive bacteria. The maximum resistance was found to ampicillin, gentamicin, ciprofloxacin, while in Gram-negative bacteria, the maximum resistance was found to imipenem, gentamicin, ciprofloxacin, ceftazidime, and amikacin. The occurrence of multidrug resistance phenotype was as follows: P. aeruginosa (30.3 %), Enterobacter spp (11.1 %), Escherichia coli (10.5 %), Citrobacter spp (2.1 %), S. epidermidis (2.8 %), S. aureus, and S. saprophyticus (0.7 %).

CONCLUSION

Owing to the diverse range of bacteria that because burn wound infection, regular investigation, and diagnosis of common bacteria and their resistance patterns is recommended to determine the proper antibiotic regimen for appropriate therapy.

Low prevalence of Moraxella catarrhalis in the patients who suffered from conjunctivitis in the southwest of Iran

Objective

Moraxella catarrhalis is a non-motile Gram-negative diplococcus bacterium that contributed to several human infections including conjunctivitis. This study aimed to reveal the prevalence of M. catarrhalis in patients who suffered from conjunctivitis in Ahvaz city, southwest of Iran.

Results

Out of 100 conjunctiva swab specimens, M. catarrhalis was isolated only from one (1%) conjunctivitis cases using the culture method. This strain was isolated from a 34 years old female patient. Also, the results of the polymerase chain reaction (PCR) were in agreement with the culture method, and the specimen that showed positive culture was also positive for specific gene of M. catarrhalis. The remaining 99 specimens did not show positive results with any of the culture and PCR methods.

Resistotyping and extended-spectrum beta-lactamase genes among Escherichia coli from wastewater treatment plants and recipient surface water for reuse in South Africa

The spread of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has increased in different environments. This study aimed to evaluate the patterns of antibiotic resistance and ESBL genes among E. coli isolates collected from wastewater and recipient surface water in South Africa. Fifteen samples containing nine wastewater and six river water samples were collected from a local wastewater treatment plant. The E. coli isolates were detected using standard microbiology methods. Antibiotic susceptibility testing was performed using disc diffusion agar. The occurrence of bla_CTX-M, bla_SHV and bla_TEM ESBL genes was investigated by PCR. Exactly 140 isolates were selected from the primary enumeration plates with a log₁₀ CFU/mL count that ranged from 4.1 to 4.2 (influent), 4.2 to 4.5 (biofilter) and 2.5 to 3.3 (effluent). The wastewater effluent showed an impact on the receiving water environment, as the treatment efficiency was 92% and the downstream log₁₀ CFU/mL count (range, 3.6–3.8 log₁₀ CFU/mL) was higher than the upstream count (range, 3.3–3.6 log₁₀ CFU/mL). Antibiotic testing results showed that 40% to 100% of E. coli isolates were resistant to ampicillin, penicillin, tetracycline and cefotaxime but susceptible to imipenem, meropenem and ciprofloxacin. A total of 40 studied isolates (28.6%) had both the bla_TEM and bla_CTX-M genes, while no bla_SHV was detected. The wastewater treatment plants contributed multidrug-resistant ESBL-producing E. coli isolates that can be potential environmental health risks. Regular monitoring policies are recommended to prevent the spread of antibiotic resistance in the region.

Emergence of multidrug-resistant Shigella species harboring extended-spectrum beta-lactamase genes in pediatric patients with diarrhea from southwest of Iran

Owing to the scarce evidence about the multidrug-resistant (MDR) beta-lactamase-producing Shigella isolates in Iran, this study aimed to evaluate the occurrence of extended-spectrum beta-lactamases (ESBL) and AmpC β-lactamases in Shigella species collected in the southwest of Iran. This study was conducted on Shigella species isolated from stool samples of pediatric patients aged less than 15 years suffering from diarrhea. These isolates were identified by bacteriology tests, serotyping, and polymerase chain reaction (PCR). The antibiotic resistance was determined by disc diffusion. The production of ESBLs and AmpC was investigated by phenotypic confirmatory tests and PCR. In total, 79 Shigella isolates, including 46.8% (n = 37) of S. flexneri and 53.2% (n = 42) of S. sonnei, were isolated, respectively. The most effective antibiotic was imipenem with 93.7% of susceptibility followed by ampicillin (29.1%), and cotrimoxazole (30.4%).The resistance rates of ceftriaxone, ceftazidime, and cefotaxime were 41.8%, 34.2%, and 41.8%, respectively. Also, a total of 57 (72.2%) isolates showed MDR profiles. The phenotypic tests showed that 43.0% (34/79) of isolates can produce ESBLs, and no one was positive for ApmC. The frequency of bla_TEM and bla_CTX-M were 30.4% and 32.9%, respectively, while the bla_PER, bla_SHV, and AmpC genes were not detected. The ESBL-producing isolates had a significant (p-value ˂ 0.05) resistance rate against ceftriaxone, ceftazidime, cefotaxime, cefepime, erythromycin, and amikacin. The significant prevalence of MDR Shigella isolates harboring ESBL genes highlights the need for effective surveillance measures to prevent the more spread of drug resistance among species.