Bacterial profiles and their antibiotic resistance background in superinfections caused by multidrug-resistant bacteria among COVID-19 ICU patients from southwest Iran.

This study investigated the bacterial causes of superinfections and their antibiotic resistance pattern in severe coronavirus disease 2019 (COVID-19) patients admitted to the intensive care unit (ICU) of Razi Hospital in Ahvaz, southwest Iran. In this cross-sectional study, endotracheal tube (ETT) secretion samples of 77 intubated COVID-19 patients, confirmed by reverse transcription-quantitative polymerase chain reaction, were investigated by standard microbiology test and analytical profile index kit. Antibiotic susceptibility testing was performed by disc diffusion. The presence of Haemophilus influenzae and Mycoplasma pneumoniae was investigated by the polymerase chain reaction (PCR). Using culture and PCR methods, 56 (72.7%) of the 77 COVID-19 patients (mean age of 55 years, 29 male and 27 female) had superinfections. Using culture, 67 isolates including 29 (43.2%) Gram-positive and 38 (56.7%) Gram-negative bacteria (GNB) were identified from 49 COVID-19 patients. The GNB were more predominant than the Gram-positive pathogens. Klebsiella pneumoniae (28.4%, n = 19/67) was the most common isolate followed by Staphylococcus aureus (22.4%, n = 15/67). Using PCR, 10.4% (8/77) and 11.7% (9/77) of ETT secretion specimens had H. influenzae and M. pneumoniae amplicons, respectively. Gram-positive and Gram-negative isolates showed high resistance rates (>70.0%) to majority of the tested antibiotics including fluoroquinolone, carbapenems, and cephalosporins and 68.7% (46/67) of isolates were multidrug-resistant (MDR). This study showed a high frequency rate of superinfections by MDR bacteria among COVID-19 patients in southwest Iran. The prevention of long-term consequences caused by COVID-19, demands continuous antibiotic surveillance particularly in management of bacterial superinfections.

Antibacterial effects of Octenicept, and benzalkonium chloride on Acinetobacter baumannii strains isolated from clinical samples and determination of genetic diversity of isolates by RAPD-PCR method.

BACKGROUND: Acinetobacter baumannii (A. baumannii) is among the important causes of nosocomial infections. Due to the emergence of antibiotic resistance, many problems have been raised in the successful treatment of patients infected by this bacterium with the subsequent mortality. Therefore, the present study was performed to evaluate the antibacterial effect of Octenicept (OCT), and Benzalkonium chloride (BZK) against A. baumannii strains isolated from clinical samples, and to determine the genetic diversity of strains by RAPD-PCR method. METHODS: A total of 119 A. baumannii isolates were collected and confirmed by conventional culture and biochemical tests and PCR assay. Susceptibility of the isolates to antibiotics was evaluated by standard antibiotic susceptibility testing (AST). For antiseptics OCT and BZK, Minimum inhibitory concentration (MIC) was assessed by broth microdilution method. The prevalence of qacE and qacΔE1 genes related to antiseptics was estimated by PCR assay. Finally, genetic diversity of strains was determined by using RAPD-PCR. RESULTS: All 119 suspected isolates were confirmed as A. baumannii using conventional microbiologic tests and PCR assay. The isolates were mostly originated from blood samples. In AST, the lowest resistance was seen for ciprofloxacin and gentamicin. For antiseptics, the MIC values were reported as 15.26 µg/ml for OCT and 640 µg/ml for BZK. The antiseptic genes of qacE and qacΔE1 were found to be present in 56 (47.05%) and 59 (49.57%) of isolates respectively. RAPD typing revealed great diversity among A. baumannii isolates, with 37 clusters in isolates from ICU, of which 32 clusters were single and 5 were multiple. CONCLUSIONS: Considering the increase of resistance to antiseptics, it is of importance to monitor the susceptibility of A. baumannii to antiseptics and to promote antiseptic stewardship in hospitals. Furthermore, in this study great diversity was observed among A. baumannii isolates, which is important in understanding the molecular epidemiology of the outbreaks caused by this organism in the hospitals.

Distribution of genes encoding resistance to macrolides, lincosamides, and streptogramins among methicillin-resistant Staphylococcus aureus strains isolated from burn patients.

The increasing resistance to macrolide, lincosamide, and streptogramin B agents among methicillin-resistant Staphylococcus aureus (MRSA) is a worldwide problem for the health community. This study aimed to investigate the prevalence of ermA, ermB, ermC, and msrA in MRSA strains isolated from burn patients in Ahvaz, southwest of Iran. A total of 76 isolates of S. aureus were collected from January to May 2017 from Taleghani Burn Hospital in Ahvaz. Among 76 S. aureus strains collected, 60 (78.9%) isolates were MRSA. The antimicrobial susceptibility testing for MRSA showed extreme high resistance rate to clarithromycin (100%) and azithromycin (100%), followed by erythromycin (98.3%). The PCR assay revealed that the frequency rates of msrA, ermA, and ermC genes were 23 (38.3%), 28 (46.7%), and 22 (36.7%), respectively. In addition, none of the MRSA isolates had the ermB gene. Because of the high prevalence of macrolide and lincosamide resistance found in MRSA isolates from infections of burn patients in Ahvaz, southwest of Iran, it is recommended that local periodic survey be performed for controlling the dissemination of antimicrobial resistance.

Preparing and evaluating the anti-microbial effect of Allium jesdianum mouthwash on some of the most common oral microorganisms.

Background: Due to the increasing resistance of bacteria to antibiotics and anti-bacterial compounds in plants, Allium jesdianum Boiss plant extract can be used in mouthwash compounds with its anti-microbial activity. Methods and Materials: The anti-bacterial and anti-fungal activity of A. jesdianum mouthwash was investigated on Streptococcus mutans, Streptococcus sanguis, S. salivarius and Candida albicans, and Candida tropicalis. To analyse the anti-microbial effect of this mouthwash, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the broth microdilution method. Results: The average MIC and MBC of A. jesdianum mouthwash for S. mutans were 1.56 and 3.12 (mg/ml), respectively, for S. salivarius, 0.25 and 0.65 (mg/ml), and for S. sanguis, respectively, 0.25 and 0.65 (mg/ml). The highest MIC and MBC values were for S. mutans, and the MIC and MBC values were equal for S. sanguis and S. salivarius. Average MIC and MBC were determined as 2.41 and 4.16 (mg/ml) for C. albicans and 2.34 and 5.72 (mg/ml) for C. tropicalis, respectively. MIC values of mouthwash were higher for C. albicans and MBC values for C. tropicalis. Conclusion: Our results showed a promising anti-fungal-anti-bacterial effect of A. jesdianum extract. A. jesdianum extract may be used as an alternative to chemical mouthwashes.

Distribution of genes encoding resistance to aminoglycoside modifying enzymes in methicillin-resistant Staphylococcus aureus (MRSA) strains.

Today Methicillin-Resistant Staphylococcus aureus (MRSA) have acquired multiple resistance to a wide range of antibiotics including aminoglycosides. So, this study was aimed to investigate the rate of aminoglycoside resistance and the frequency of aminoglycoside resistance mediated genes of aac(Ia)-2, aph(3)-IIIa and ant(4')-Ia among MRSA strains. A total of 467 staphylococci isolates were collected from various clinical samples. S. aureus strains were identified by standard culture and identification criteria and investigating of presence of 16S rRNA and nuc genes. Cefoxitin disk diffusion, and oxacillin-salt agar screening methods were used to detect the MRSA strains with subsequent molecular identification for the presence of mecA gene. Antibiotic susceptibility of MRSA strains against aminoglycoside antibiotics was evaluated by using agar disk diffusion method. Multiplex PCR for the presence of aac(Ia)-2, aph(3)-IIIa and ant(4')-Ia encoding genes for aminoglycosides were performed for MRSA strains. From total staphylococci tested isolates, 262 (56.1%) were identified as S. aureus, of which 161 (61.45%) were detected as MRSA and all comprised mecA gene. The resistance pattern of MRSA strains to aminoglycoside antibiotics were: gentamicin 136 (84.5%); amikacin 125 (77.6%); kanamycin 139 (86.3%); tobramycin 132 (82%); and neomycin 155 (96.3%). The frequency of aac(Ia)-2, aph(3)-IIIa, and ant(4')-Ia genes among MRSA strains, were 64%, 42% and 11.8% respectively. In conclusion, as MRSA strains are of great concern in human infections, the results of present study could provide a useful resource for health sectors for choosing appropriate antibiotics for the effective treatment of infections due to MRSA strains.

Identification of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from burn patients by multiplex PCR.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) as important human pathogens are causes of nosocomial infections worldwide. Burn patients are at a higher risk of local and systemic infections with these microorganisms. OBJECTIVE: A screening method for MRSA by using a multiplex polymerase chain reaction (PCR) targeting the 16S ribosomal RNA (rRNA), mecA, and nuc genes was developed. The aim of the present study was to investigate the potential of this PCR assay for the detection of MRSA strains in samples from burn patients. METHODS: During an 11-month period, 230 isolates (53.11%) of Staphylococcus spp. were collected from burn patients. The isolates were identified as S. aureus by using standard culture and biochemical tests. DNA was extracted from bacterial colonies and multiplex PCR was used to detect MRSA and MRCoNS strains. RESULTS: Of the staphylococci isolates, 149 (64.9%) were identified as S. aureus and 81 (35.21%) were described as CoNS. Among the latter, 51 (62.97%) were reported to be MRCoNS. From the total S. aureus isolates, 132 (88.6%) were detected as MRSA and 17 (11.4%) were methicillin-susceptible S. aureus (MSSA). The presence of the mecA gene in all isolates was confirmed by using multiplex PCR as a gold standard method. CONCLUSION: This study presented a high MRSA rate in the region under investigation. The 16S rRNA-mecA-nuc multiplex PCR is a good tool for the rapid characterization of MRSA strains. This paper emphasizes the need for preventive measures and choosing effective antimicrobials against MRSA and MRCoNS infections in the burn units.