Improvement of semen parameters after antibiotic therapy in asymptomatic infertile men infected with Mycoplasma genitalium.

OBJECTIVES: To elucidate the association between asymptomatic infections caused by Mycoplasma genitalium and male infertility, and evaluate the role of antibiotic therapy in treatment of this failure. METHODS: A total of 165 infertile males having abnormal semen parameters (study group) and 165 healthy fertile men (control group) were included. Semen samples were taken from all participants and after analyzing for semen parameters, undergone real-time PCR, microbial culture, and reactive oxygen species (ROS), as well as total antioxidant capacity (TAC) assays. Infected individuals of study group were treated with antibiotic. One month after the treatment completion, second semen samples were taken and subjected to all the tests mentioned. The data were analyzed using SPSS statistical software, version 22.0. RESULTS: The frequency of M. genitalium was significantly higher in the infertile men compared with the fertile ones (9.7% vs. 1.2%; p = 0.001). Mean cycle threshold (C t) value was lower in infected infertile than infected fertile men (p < 0.001). All semen parameters, except volume, pH, and viscosity, were improved (p < 0.05), most of which reached their normal range; leukocytes in seminal fluid decreased (p = 0.02), the level of TAC was elevated (p = 0.002), and ROS level as well as ROS/TAC ratio reduced after antibiotic treatment (p = 0.03). Wives of seven infected infertile men (43.8%) became pregnant 4 months after the treatment completion. CONCLUSIONS: Asymptomatic infection caused by M. genitalium is correlated with male infertility and antibiotic therapy can improve the semen quality and be used to treat male infertility.

Characterization of virulence factors, antimicrobial resistance pattern and clonal complexes of group B streptococci isolated from neonates.

Between January and December 2013, swab samples were taken for the throat and external ear canals of 1037 newborns for screening of Group B Streptococcus (GBS or S. agalactiae). Isolates were analyzed form Multilocus sequence typing (MLST), capsular type, virulence genes and antibiotic susceptibility. The MLST analysis of 19 GBS isolates showed 8 sequence types (STs). Overall the most common STs were ST19 and ST28. Other STs were ST1, ST4, ST8, ST12, ST335 and ST734 (a new ST). The most common clonal complexes (CCs) were CC19 (68.4%) and CC10 (21%). The scpB, hlyB and bca virulence genes were detected in all STS, while the bac gene was predominant in ST12 with capsular type (CT) Ib. The IS1548 and the rib genes were particularly prevalent in CTIII and were detected in isolates belong to ST19, ST335 and ST734 and were grouped in CC19. All isolates were susceptible to penicillin, vancomycin, linezolid and quinupristin-dalfopristin. Resistance to tetracycline was observed in all 19 (100%) strains and was correlated with presence of the tetM gene except for one isolate with ST12. All the ST8 and ST12 isolates were resistant to macrolide carrying two resistance genes; the ermTR and the ermB, respectively. The results of this study showed that the CC19 was a major clone in the neonatal intensive care unit (NICU) of Imam Khomeini hospital which can cause severe infections in susceptible neonates (particularly in premature infants). As a result, an intensive infection control policy is needed to prevent the spread of this clone.

Assessment and comparison of probiotic potential of four Lactobacillus species isolated from feces samples of Iranian infants.

The probiotic potential of Lactobacillus species isolated from infant feces was investigated. For this study, the antibiotic susceptibility, tolerance in gut-related conditions, antimicrobial activity, and ability to adhere to a human colorectal adenocarcinoma cell line (Caco-2 cells) of four common Lactobacillus species (Lactobacillus paracasei [n = 15], Lactobacillus rhamnosus [n = 45], Lactobacillus gasseri [n = 20] and Lactobacillus fermentum [n = 18]) were assessed. Most isolates that which were sensitive to imipenem, ampicillin, gentamycin, erythromycin and tetracycline were selected for other tests. L. gasseri isolates had the greatest sensitivity to gastric and intestinal fluids (<10% viability). L. fermentum (FH5, FH13 and FH18) had the highest adhesion to Caco-2 cells. The lowest antibacterial activity against pathogenic bacteria was shown by L. gasseri strains in spot tests. Furthermore, non-adjusted cell-free culture supernatants with low pH had greater antimicrobial activity, which was related to organic acid. The results showed that some isolates of L. rhamnosus and L. fermentum are suitable for use as a probiotic.

Evaluation of a new antigen for diagnosis of Helicobacter pylori infection in stool of adult and children.

BACKGROUND: Nowadays, there is an increasing interest in noninvasive methods to diagnose Helicobacter pylori infection. Indeed, they can profitably replace endoscopy in predicting the diagnosis. The stool antigen test for H. pylori is a noninvasive immunoassay to diagnose active infection with this bacterium in human fecal samples. The aim of this study was detection of alkyl hydroperoxide reductase protein (AhpC) antigen by immunoblotting in stool samples for diagnosis of H. pylori. MATERIALS AND METHODS: Chromosomal DNA from H. pylori was isolated. AhpC gene was amplified by PCR, These amplicons were cloned into pTZ57R/T cloning vector then subcloned into pQE30 expression vector and overexpressed using isopropyl-beta-D-thiogalactopyranoside in E. coli M15. AhpC protein was purified by affinity chromatography. Rabbits were immunized with the purified AhpC protein for the production of antibodies. To determine the accuracy of the test for diagnosing H. pylori infection from stool, we evaluated 84 patients (6-81 years old) using Western blot analysis by rabbit anti-AhpC antibody. Positive rapid urease test on biopsy samples was considered as the gold standard. RESULTS: AhpC gene was overexpressed, and AhpC protein was purified. Rabbit anti-AhpC antibody produced after immunization with the purified AhpC protein. By immunoblotting, we detected AhpC protein in the positive stool samples. The test showed a 83.3% sensitivity (95% CI: 69.8-92.5%) and a 91.7% specificity (95% CI: 77.5-98.2). Among the children, the sensitivity was 88.2% (95% CI: 63.6-98.5) and the specificity was 100% (95% CI: 69.2-100); in adults, the sensitivity and specificity were 80.6% (95% CI: 62.5-92.5) and 88.5% (95% CI: 69.8-97.6), respectively. CONCLUSIONS: Using of AhpC antigen for diagnosis of H. pylori infection is a useful noninvasive method, accurate in adolescents and children, and can be used for the development of a stool antigen detection kit for H. pylori.

Phenotypic and genotypic evaluation of fluoroquinolone resistance in clinical isolates of Staphylococcus aureus in Tehran.

BACKGROUND: Fluoroquinolones are broad-spectrum antibiotics widely used in the treatment of bacterial infections such as Staphylococcus aureus isolates. Resistance to these antibiotics is increasing. MATERIAL/METHODS: The occurrence of mutations in the grlA and gyrA loci were evaluated in 69 fluoroquinolone-resistant S. aureus isolates from 2 teaching hospitals of Tehran University of Medical Sciences. RESULTS: Out of the 165 S. aureus isolates, 87 (52.7%) were resistant to methicillin and 69 (41.8%) were resistant to fluoroquinolone. Fluoroquinolone-resistant S. aureus isolates had a mutation at codon 80 in the grlA gene and different mutational combinations in the gyrA gene. These mutational combinations included 45 isolates at codons 84 and 86, 23 isolates at codons 84, 86 and 106 and 1 isolate at codons 84, 86 and 90. Fluoroquinolone-resistant S. aureus isolates were clustered into 33 PFGE types. CONCLUSIONS: The findings of this study show that the fluoroquinolone-resistant S. aureus strains isolated in the teaching hospitals in Tehran had multiple mutations in the QRDRs region of both grlA and gyrA genes.

Analysis of Helicobacter pylori genotypes in Afghani and Iranian isolates.

The geographical variation in Helicobacter pylori genotypes is an observed phenomenon. Cytotoxin associated genes A (cagA) and E (cagE), and vacuolating cytotoxin (vacA) genotypes of H. pylori are associated with peptic ulcer disease (PUD). This study compared the distribution of these genotypes in Iranian and Afghani isolates and their association with clinical outcomes. H. pylori infected patients, as proven by positive culture, were recruited prospectively. A total of 70 patients, 55 Iranian (26 men and 29 women, mean age 48 +/- 18 years) and 15 Afghani immigrants (13 men and 2 women, mean age 34.8 +/- 11 years) living in Tehran, Iran were enrolled in this study. DNA was extracted from isolated H. pylori and polymerase chain reaction was carried out to determine the cagA and cagE status and vacA alleles. The number of gastric cancer, peptic ulcer and gastritis cases was 11, 23 and 36, respectively. The cagA positive isolates were more common in Iranian (67%) than Afghani isolates (60%). cagE was positive in 53% of Afghani compared to 51% of Iranian isolates. The most common vacA s-region genotype was s1; 80% in Afghani and 67% in Iranian. The slml was a frequently observed genotype in Afghani strains (53%) while s1m2 (47%) was more common in strains isolated from Iranian patients. There is a difference in the H. pylori strains between Iranian and Afghani groups, for instance Iranian isolates were similar to European isolates while Afghani isolates were similar to isolates from India. However, there was no significant association between cagA, cagE and vacA genotypes and clinical outcomes in Iranian and Afghani patients.

Distribution of Helicobacter pylori cagA, cagE, oipA and vacA in different major ethnic groups in Tehran, Iran.

BACKGROUND AND AIM: There are geographical variations in Helicobacter pylori virulence genes; cagA, cagE, vacA and oipA. The present study compared the distribution of these genotypes in major ethnic groups residing in Tehran, Iran and their association with clinical outcomes. METHODS: A total of 124 H. pylori-positive patients living in Tehran were enrolled in this study. The ethnic distribution was 74 Persians, 33 Turks and 17 other ethnics including Kurds, Lurs, Afghanis and Arabs. The presence of the cagA, cagE and oipA genes and vacA alleles (signal [s] and middle [m] region) were determined by polymerase chain reaction (PCR) from H. pylori DNA. RESULTS: The cagA-positive status was predominant in all three ethnic groups (e.g. 65% in Persians and 73% in Turks). In contrast, the cagE-positive status was less than half in Persians (47%) and Turks (30%), whereas it was 77% in other ethnicities (P = 0.008). The predominant vacA genotypes were s1 and m1 in all three ethnic groups (e.g. 68% in Persians and 70% in Turks were s1). There was no significant association between cagA and cagE status or vacA genotypes and clinical outcomes. The oipA-positive strains were more common in non-ulcer dyspepsia (NUD) (63%) than in peptic ulcer patients (15%) (P = 0.001) in Persians, but the association was not observed in other ethnic groups. CONCLUSION: There are some differences in the H. pylori genotypes among the ethnic groups in Iran. However, none of these markers seemed to be clinically helpful in predicting the clinical presentation of a H. pylori infection in Iran.

Prevalence of enteropathogenic and shiga toxin-producing Escherichia coli among children with and without diarrhoea in Iran.

The aim of the study was to determine the rates of detection of enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing E. coli (STEC) strains among children in two randomly-selected populations in Iran. In total, 1,292 randomly-selected faecal samples from children aged less than 10 years were screened for EPEC and STEC. Of the 1,292 cases participated in the study, 184 had diarrhoea, and 1,108 were healthy/asymptomatic children. The conventional culture method and slide agglutination with 12 different commercial EPEC antisera were used for the detection of EPEC. The colony sweep polymyxin-B extraction method, non-sorbitol fermentation (NSF) phenotype, and slide agglutination with O157: H7 antisera were used for the screening and detection of STEC. Of EPEC belonging to 11 different serogroups, 0111 and 0127 were most commonly found in 36.4% of the diarrhoeal cases and 7.2% of the asymptomatic children. A significant association (p<0.05) was found between isolation of EPEC and diarrhoea. 8.7% of the diarrhoeal cases and 2% of children without diarrhoea were infected with STEC, but none of the isolates belonged to the 0157:H7 serotype. A significant association (p<0.05) was found between STEC and diarrhoeal cases. Based on these findings, it can be concluded that different EPEC serogroups may be agents of endemic infantile diarrhoea, and STEC strains are an important enteropathogen among young children.

Determination of carbapenem resistance mechanism in clinical isolates of Pseudomonas aeruginosa isolated from burn patients, in Tehran, Iran.

Carbapenems are the most important therapeutic options that effect against serious infections caused by multidrug resistant Pseudomonas aeruginosa (MDR-PA) isolates. Carbapenems resistant isolates of P. aeruginosa are increasing worldwide. The aim of this study was to determine the carbapenem resistance mechanisms in clinical P. aeruginosa isolates from burn patients, in Tehran, Iran. A total of 53 non-duplicated isolates of carbapenem-resistant P. aeruginosa were collected from burn patients. The presence of carbapenemase genes were determined by PCR. AmpC overproducer isolates were detected by phenotypic method. The mutation and transcription level of oprD were determined by PCR-sequencing and quantitative Real-time PCR (RT-PCR), respectively. Twenty-seven (50.9%) isolates were positive for carbapenemase (blaVIM=25 and blaIMP=2) and showed high-level resistance to imipenem and meropenem. Twenty-eight isolates were AmpC overproducers. All isolates had a mutation in the oprD gene and down-regulation of oprD was found in 56.6% of MDR-PA isolates. Although the presence of carbapenemase is the common mechanism of resistant to carbapenem, but carbapenem resistance was found by oprD mutation-driven and the AmpC overproducing isolates in Tehran, Iran.

Asymptomatic Infection With Mycoplasma hominis Negatively Affects Semen Parameters and Leads to Male Infertility as Confirmed by Improved Semen Parameters After Antibiotic Treatment.

OBJECTIVE: To elucidate the association between asymptomatic infections caused by Mycoplasma hominis and male infertility and to evaluate the role of antibiotic therapy in the treatment of this failure. MATERIALS AND METHODS: A total of 165 infertile men having abnormal semen parameters (study group) as well as 165 healthy fertile men (control group) were included in this study. Semen samples were taken from all participants and, after analyzing for semen parameters, real-time polymerase chain reaction, microbial culture, and reactive oxygen species (ROS) as well as total antioxidant capacity (TAC) assays were performed. Infected individuals of the study group were treated with antibiotic. One month after the treatment completion, second semen samples were taken and all the tests mentioned were performed. The data were analyzed using SPSS statistical software, version 22.0. RESULTS: The frequency of M. hominis was significantly higher in the infertile men compared with the fertile ones (14.5% vs 3.6%, P = .001). The mean cycle threshold (Ct) value was lower in infected infertile men than in infected fertile men (P < .001). All semen parameters, except volume, pH, and viscosity, were improved (P < .05), most of which reached their normal range; leukocytes in seminal fluid were eliminated (P = .04); the level of TAC elevated (P < .001); and the ROS level as well as the ROS-to-TAC ratio reduced after antibiotic treatment (P = .02). Moreover, wives of 14 infected infertile men (58.3%) became pregnant 4 months after the treatment completion. CONCLUSION: Our data suggest that asymptomatic infection caused by M. hominis is correlated with male infertility and antibiotic therapy can improve the semen quality and fairly treat the male infertility.

Detection of typical and atypical enteropathogenic Escherichia coli (EPEC) in Iranian children with and without diarrhoea.

The present study was performed to investigate the contribution of typical and atypical enteropathogenic Escherichia coli (EPEC) as a cause of infectious diarrhoea among children less than 10 years old in Iran. During the summer months, 247 specimens from children with diarrhoea and 1108 from asymptomatic children were analysed for the presence of EPEC and other bacterial pathogens. Potential enteric pathogens were identified in 140 cases of children with diarrhoea (56.7%). EPEC was the most frequently identified agent (111 cases), followed by Shiga toxin-producing E. coli (13), Shigella (9), Salmonella (6) and Aeromonas sp. (1). EPEC isolates were examined for the presence of eaeA, bfpA and stx genes by PCR. EPEC isolates were classified as typical (eaeA+ bfpA+) or atypical (eaeA+ bfpA-). Typical EPEC was diagnosed in 35 cases (11.8%), compared with 8 (0.4%) in the asymptomatic group (P<0.05). Atypical EPEC strains were isolated from 23 cases (9.3%), compared with 13 (1.2%) of the healthy control group (P<0.05). In conclusion, the data suggest that typical and atypical EPEC are an important cause of diarrhoea in Iranian children.

Prevalence of Urogenital Mycoplasmas in Iran and Their Effects on Fertility Potential: A Systematic Review and Meta-Analysis.

BACKGROUND: Urogenital mycoplasmas are potentially pathogenic species causing genitourinary tract infections that may be initially asymptomatic but can progress and lead to severe complications and threaten reproductive health. However, the overall prevalence rate of this bacterium and its probable impacts on fertility potential have yet to be determined. METHODS: We searched both English and Persian electronic databases using key words such as "Mycoplasma," "Ureaplasma," "M. hominis," "M. genitalium," "U. urealyticum," "U. parvum," "prevalence," and "Iran". Finally, after some exclusion, 29 studies from different regions of Iran were included in our study, and a meta-analysis was performed on collected data. RESULTS: Urogenital mycoplasmas prevalence for women and men was high and ranged from 2%-40.5% and 2%-44.3%, respectively. The pooled prevalence in the male population was 11.1% (95% CI, 7.4%-16.4%) and in female was 12.8% (95% CI, 9.8%-16.5%). The prevalence of these bacteria was significantly higher in infertile men compared with that in fertile men. A high level of heterogeneity was observed for both men (I(2) = 92.4%; P<0.001) and women (I(2) = 93.3%; P<0.001). Some evidence for publication bias was observed in both men [Egger's test (two-tailed P=0.0007), and Begg's test (two-tailed P=0.0151)] and women [Egger's test (two-tailed P=0.0006), and Begg's test (two-tailed P=0.0086)] analysis. CONCLUSION: Since urogenital mycoplasmas may play a role in male infertility, screening strategies, particularly for asymptomatic individuals, and treatment of infected ones, which can reduce consequent complications, looks to be necessary.

Association of Chlamydia trachomatis with infertility and clinical manifestations: a systematic review and meta-analysis of case-control studies.

Background Chlamydia trachomatis is one of the sexually transmitted pathogens causing reproductive health-threatening diseases worldwide. However, its role in infertility, particularly in asymptomatic individuals, is not yet definitely determined. Methods For the study, electronic databases were searched using the following keywords; 'Chlamydia trachomatis', 'prevalence', 'frequency', 'fertile', 'infertile', 'case', 'control', 'symptomatic' and 'asymptomatic'. Finally, after some exclusions, 34 studies (19 fertile-infertile and 15 symptomatic-asymptomatic) from different countries were included in the study and meta-analysis was performed on the data collected. Results Odds ratios (ORs) for urogenital C. trachomatis prevalence in males in the fertile-infertile group, for infertile and fertile individuals, ranged from 1.3-3.7 and in females from 1.04-4.8, and the overall OR for both genders was 2.2 (95% CI). In the symptomatic-asymptomatic group, the overall OR in males and females was 4.9 (95% CI = 1.1-21.7) and 3.3 (95% CI = 1.7-6.3), respectively. In all of the analyses, there were high levels of heterogeneity (I(2) >50%, p-value <0.05) and, except for the females in the symptomatic-asymptomatic group, neither Egger's tests nor Begg's tests were statistically significant for publication bias. Conclusions C. trachomatis can impact on the potential for fertility and cause clinical manifestations and complications in both males and females. Thus, national programmes for adequate diagnosis, screening and treatment of infected individuals, particularly asymptomatic ones, seem to be necessary.

Prevalence of genital Chlamydia trachomatis in Iran: a systematic review and meta-analysis.

OBJECTIVE: To determine the overall prevalence of Chlamydia trachomatis in Iranian males and females and to find out the effect of this bacterium on fertility potential and its association with urogenital symptoms. METHODS: We searched both English and Persian electronic databases using keywords 'Chlamydia', 'Chlamydia trachomatis', 'prevalence', 'incidence', 'frequency', 'epidemiology' and 'Iran'. Finally, after some exclusion, 34 studies from different regions of Iran were included in our study, and a meta-analysis was performed to determine pooled prevalence estimates for each group. RESULTS: C. trachomatis prevalence for women and men was high and ranged from 0 to 32.7% and 0 to 23.3%, respectively (95% CI). The pooled prevalence of the bacterium in the female population was 12.3% (95% CI: 10.6-14.2%) and in men was 10.9% (95% CI: 7.6-15.4%). A high level of heterogeneity was seen for both men (I(2) = 77.4%; P < 0.001) and women (I(2) = 77.5%; P < 0.001); but in men and not in women, some evidence for publication bias was observed [Egger's test (two-tailed P = 0.013); Begg's test (two-tailed P = 0.025)]. In females analysis of symptomatic/infertile group with asymptomatic/fertile group in females, the overall OR was above 1 and the overall P-value was below zero. CONCLUSIONS: This bacterium may play a role in female infertility or be associated with clinical manifestations; thus, planning national programmes for adequate diagnosis of genital infections caused by this pathogen is necessary. Furthermore, screening strategies, particularly for asymptomatic individuals, and treatment of infected people can reduce consequent complications.

Virulence profiling and genetic relatedness of Shiga toxin-producing Escherichia coli isolated from humans and ruminants.

In the present study the occurrence, genotypic characteristics and relatedness of Shiga toxin-producing Escherichia coli (STEC) isolated from 235 fecal samples of diarrheic children (n=75), sheep (n=80), and cattle (n=80) were investigated. Overall, STEC was found in 4%, 61.2%, and 18.7% of diarrheic children, sheep and cattle, respectively. Three of the four STEC isolates from diarrheic children yielded the stx1/ehly profile. The predominant virulence profile of sheep isolates was stx1/ehly (85.2%), but cattle isolates were heterogeneous. Genetic relatedness and diversity of 36 selected isolates were analyzed by enterobacterial repetitive consensus sequences fingerprinting (ERIC) and phylogrouping. In total, 19 ERIC-types were observed in humans (n=2), sheep (n=5), and cattle (n=12) isolates. The majority of the sheep STEC were assigned into B1 phylogroup (83.3%), but cattle isolates belonged to different phylogroups with B1 predominance. Three human STEC isolates had the major characteristics of sheep isolates but revealed distinct fingerprint. These findings indicate that cattle can potentially carry a diverse group of STEC strains.

ISPpu22, a novel insertion sequence in the oprD porin gene of a carbapenem-resistant Pseudomonas aeruginosa isolate from a burn patient in Tehran, Iran.

BACKGROUND AND OBJECTIVES: The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistance to carbapenems such as imipenem and meropenem in Pseudomonas aeruginosa. MATERIALS AND METHODS: In this study, we investigated intrinsic resistance to carbapenems including mutation of oprD and AmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patient by phenotypic and molecular methods. RESULTS: In our study, the carbapenem-resistant P. aeruginosa isolate was resistant to imipenem, meropenem, cefepime, gentamicin, ceftriaxone, carbenicillin, aztreonam and ciprofloxacin but was susceptible to ceftazidime and polymyxin B. The minimum inhibitory concentrations (MICs) against imipenem, meropenem and ceftazidime were 64 µg/ml, 16 µg/ml and 2µg/ml, respectively. The isolate was ESBLs and AmpC overproducer. No carbapenemase activity was detected by Modified Hodge test (MHT). This isolate was carrying only bla OXA-10 . PCR amplification and sequencing of oprD performed on isolate resulted in PCR product of 2647bp. Sequence analysis of the 2647bp product revealed insertion of a sequence of 1232 bp at position 8 in coding region of oprD. CONCLUSION: According to the results of this study, oprD mutation and AmpC overproduction can cause the main mechanism of resistance of P. aeruginosa to carbapenems.

High Incidence of Macrolide and Tetracycline Resistance among Streptococcus Agalactiae Strains Isolated from Clinical Samples in Tehran, Iran.

BACKGROUND: Streptococcus agalactiae or Group B Streptococci (GBS) is an important bacterial pathogen that causes a wide range of infections including neonatal sepsis, meningitis, pneumonia and soft tissue or urinary tract infections. MATERIAL AND METHODS: One hundred and fifteen isolates of Streptococcus agalactiae collected from urine specimens of patients attending a hospital in Tehran. All isolates were screened for their capsular types and genes encoding resistance to the macrolide and tetracycline antibiotics by PCR and multiplex PCR-based methods. RESULTS: Most of isolates belonged to capsular types III (49%), V (19%), II (16%), and Ib (6%). Twelve isolates (10%) were nontypable. All isolates were susceptible to penicillin and Quinupristin-dalfopristin, but were resistant to clindamycin (35%), chloramphenicol (45%), erythromycin (35%), linezolid (1%) and tetracycline (96%). The most prevalent antimicrobial resistance gene was tetM found in 93% of the isolates followed by ermTR, ermB, and tetK, found in 23%, 16%, and 16% of isolates, respectively. The genes, tetL, tetO, ermA, ermC and mefA were not detected in any of the S. agalactiae isolates. Of the 110 tetracycline resistant S. agalactiae, 89 isolates harbored the tetM gene alone and eighteen isolates carried the tetM gene with the tetK gene. All erythromycin-resistant isolates exhibited cMLSB resistance phenotype, 22 isolates harbored the ermTR gene alone and five isolates carried the ermTR gene with the ermB gene. The rate of coexistence of genes encoding the erythromycin and tetracycline resistance determinants was 34%. CONCLUSION: The present study demonstrated that S. agalactiae isolates obtained from urine samples showed a high rate of resistance to tetracycline, chloramphenicol and macrolide antibiotics and were commonly associated with the resistance genes temM, ermTR or ermB.

Virulence factors, antimicrobial susceptibility and molecular characterization of Streptococcus agalactiae isolated from pregnant women.

Forty-one Streptococcus agalactiae isolates collected from pregnant women at 35-37 weeks of gestation were analysed for their capsular types, antimicrobial resistance determinants, distribution of virulence factors and genetic relatedness using PCR and multiplex PCR. Capsular type III was predominant (65.8%), followed by capsular type II (14.6%), Ib (7.3%), and V(4.9%). All isolates were susceptible to penicillin, vancomycin, linezolid and quinupristin-dalfopristin. Resistance to tetracycline, erythromycin and clindamycin were found in 97.6%, 24.4%, and 14.6% of isolates, respectively. The most common antimicrobial resistance gene was tetM found in 97.6% of the isolates followed by ermTR and ermB found in 12% and 7.3% of isolates, respectively. The most common virulence gene was hly (100%), followed by scpB (97.6%), bca (97.6%), rib (53.65%) and bac (4.9%). The insertion sequence IS1548 was found in 63.4% of isolates. By multi locus variable number of tandem repeat analysis (MLVA) typing, 30 different allelic profiles or MLVA types (MTs) were identified. The most frequent was the MT1 (5/41, 12.2%) and followed by MT2 (4/41, 9.75%). Our data revealed that population structure of these isolates is highly diverse and indicates different MLVA types.

Detection of AmpC-ß-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient.

BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa is responsible for devastating nosocomial infections among severely burn patients. Class C of cephalosporinase (AmpC-ß-lactamases) is important cause of multiple ß-lactam resistance in P. aeruginosa. The aim of this study was to detect the AmpC-ß-lactamases producing isolates among carbapenem resistant P. aeruginosa isolated from burn patient. MATERIAL AND METHODS: a total of 100 isolates of carbapenem resistant P. aeruginosa isolates from different burn patients were investigated. Three phenotypic methods were selected for identification of the AmpC-ß-lactamases producing isolates. RESULTS: Fifty four isolates were AmpC producer as detected by AmpC disk test. Seventeen isolates were identified as AmpC producer using combined disk method. Fifty two isolates showed a twofold or threefold dilution difference between the minimum inhibitory concentration of imipenem or ceftazidime and the minimum inhibitory concentration of imipenem or ceftazidime plus cloxacillin. One isolate was identified as AmpC producer using three methods. Three isolates produced AmpC as detected by both AmpC disk test and combined disk methods and 19 isolates were found as AmpC producer using both AmpC disk test and minimum inhibitory concentration methods. Six isolates were AmpC producer as shown by the MICs of both imipenem and ceftazidime. CONCLUSION: According to the results of this study, AmpC- ß-lactamase looks to be the main mechanism of resistance of Pseudomonas aeruginosa to cephalosporins and carbapenems in the study hospital.

Determination of extended spectrum beta-lactamases, metallo-beta-lactamases and AmpC-beta-lactamases among carbapenem resistant Pseudomonas aeruginosa isolated from burn patients.

BACKGROUND: Pseudomonas aeruginosa is an important cause of morbidity and mortality in patients with burns. METHOD: A total of 214 nonduplicated burn wound isolates of P. aeruginosa were recovered from burn patients. Identification of carbapenem resistant isolates and their antimicrobial susceptibility pattern was carried out using the phenotypic methods. The presence of genes encoding extended spectrum beta-lactamases (ESBLs) and metallo-beta-lactamases (MBLs) enzymes were determined by PCR. The genetic relationships between carbapenem resistant isolates were determined by Random Amplified Polymorphic DNA (RAPD)-PCR. RESULTS: Of 214 investigated P. aeruginosa isolates, 100 (46.7%) were carbapenem resistant. All carbapenem resistant P. aeruginosa were resistant to imipenem, meropenem, ertapenem, carbenicillin, aztreonam, gentamicin and ciprofloxacin but susceptible to polymyxin B. Among 100 carbapenem resistant P. aeruginosa isolates, 3%, 65% and 52% were identified as ESBLs, carbapenemase and AmpC overproduction positive isolates respectively. The most prevalent ESBLs and MBLs genes included blaOXA-10 (97%), blaTEM (61%), blaVIM (55%), blaPER (13%), blaIMP (3%) and blaAIM (1%). RAPD analysis yielded 13 distinct profiles among 92 isolates. A dominant RAPD type was designated as A that consisting of 80 isolates. CONCLUSION: This is the first report of Adelaide IMipenmase (AIM) MBLs producing P. aeruginosa from Iran and also of the high prevalence of AmpC overproduction isolates. According to the results of current study, P. aeruginosa isolates producing OXA-10, TEM, VIM, PER and IMP beta-lactamases are frequent and the population structures of these isolates are highly similar.