Azithromycin treatment for nongonococcal urethritis negative for Chlamydia trachomatis,Mycoplasma genitalium,Mycoplasma hominis,Ureaplasma parvum,and Ureaplasma urealyticum

Some patients with nongonococcal urethritis (NGU) are negative for Chlamydia trachomatis, mycoplasmas, and ureaplasmas. The optimal antimicrobial chemotherapy for such NGU has not fully been clarified. We assessed the efficacy of azithromycin for treatment of nonmycoplasmal, nonureaplasmal, nonchlamydial NGU (NMNUNCNGU). Thirty‐eight men whose first‐pass urine was negative for Chlamydia trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum were treated with a single dose of 1 g azithromycin. Urethritis symptoms and polymorphonuclear leukocytes in urethral smears or in first‐pass urine were assessed before and after treatment with azithromycin. Thirty‐two (84.2%) of the 38 men with NMNUNCNGU showed no signs of urethral inflammation after treatment. The efficacy of this azithromycin regimen was comparable to that of the 7‐day regimen of levofloxacin, gatifloxacin, minocycline, or clarithromycin reported previously. A single dose of 1 g azithromycin, which is effective not only for NGU due to specific pathogens but also for NMNUNCNGU, is an appropriate treatment for NGU.     

Detection of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum (biovar 1) and Ureaplasma urealyticum (biovar 2) in patients with non-gonococcal urethritis using polymerase chain reaction-microtiter plate hybridization

AIM: To use polymerase chain reaction (PCR)-microtiter plate hybridization assays to detect Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum (biovar 1) and Ureaplasma urealyticum (biovar 2) in first-voided urine specimens from patients with non-gonococcal urethritis (NGU). METHODS: A total of 153 male patients with NGU, who visited one of 24 clinics in Japan, were recruited for this study. All were examined using PCR-microtiter plate hybridization assays for the presence of M. genitalium, M. hominis, U. parvum (biovar 1) and U. urealyticum (biovar 2) in first-voided urine specimens. They were also examined for the presence of Chlamydia trachomatis. RESULTS: Of these 153 patients, 73 (47.7%) were positive for C. trachomatis. Overall, the prevalence was 17.0% for M. genitalium, 16.3% for U. urealyticum (biovar 2), 7.8% for U. parvum (biovar 1) and 2.6% for M. hominis. In the 80 patients with non-chlamydial NGU, the prevalence of M. genitalium, U. urealyticum (biovar 2), U. parvum (biovar 1) and M. hominis was 23.8%, 18.8%, 8.8% and 2.6%, respectively. CONCLUSIONS: This study shows the prevalence of mycoplasmas and ureaplasmas in NGU in Japan. M. genitalium and U. urealyticum (biovar 2) might be pathogens of NGU and could be associated with persistent and recurrent urethritis. When patients with NGU are treated, such pathogens should be taken into account. This PCR-microtiter plate hybridization assay provides a useful method for diagnosing NGU caused by M. genitalium and U. urealyticum (biovar 2).     

Treatment of nongonococcal urethritis--studies on clinical effects of ofloxacin

Clinical effects of ofloxacin (OFLX) in the treatment of chlamydial urethritis was compared with those in the treatment of non-chlamydial urethritis. Chlamydia trachomatis was isolated from 33 (39.3%) out of 84 patients with nongonococcal urethritis. OFLX was administered at a dose of 100 mg, three times daily (300 mg) for 14 days. In 31 (93.3%) of the 33 patients with chlamydial urethritis, C. trachomatis was eliminated within 7 to 14 days after the start of administration, and, in two patients, inclusion bodies decreased in number but persisted. The subjective and objective clinical symptoms, urethral discharge, polymorphonuclear leucocyte (PMNL) in smears, and pyuria in VB1 of the patients with chlamydial urethritis, disappeared in 56.0, 57.6, and 63.0% of the cases, and improved in 24.0, 30.0 and 29.6% respectively, whereas those of the patients with non-chlamydial urethritis, urethral discharge, PMNL, and pyuria in VB1 disappeared in 57.6, 56.9 and 32.9%, and improved in 26.9, 13.7 and 37.9%, respectively. There was no significant difference in the clinical effects of OFLX between cases of chlamydial urethritis and those of non-chlamydial urethritis. Marked improvement in clinical symptoms were observed between day 7 and day 14 of medication in cases of both chlamydial and non-chlamydial urethritis. In nine out of 11 cases of non-chlamydial urethritis where OFLX was ineffective, no Ureaplasma nor aerobes, nor C. trachomatis, were isolated. In the remaining two cases where Ureaplasma and S. epidermidis were isolated respectively, these two bacteria were eradicated after medication, but urethral discharge and PMNL remained unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)     

武汉地区非淋菌性尿道炎患者泌尿生殖道支原体感染及药敏分析

目的：调查武汉地区非淋菌性尿道炎（NGU）患者泌尿生殖道支原体感染及耐药情况,为临床选择治疗支原体感染的抗生素提供参考依据。方法：采用支原体分离、鉴定、计数、药敏试剂盒检测拟诊为NGU患者的解脲脲原体（UU）和人型支原体（MH）,并分析药敏试验结果。结果：630例患者中支原体总阳性率38．6％,以UU（30％）感染为主,男性感染率明显高于女性。药敏试验结果显示,UU、MH和UU＋MH对药物的敏感性最高者依次为阿奇霉素和美满霉素,uu对氧氟沙星、司帕沙星和罗红霉素耐药性高,MH及uu＋MH则对罗红霉素、红霉素和克拉霉素耐药性高。结论：uu成为本地区NGU的主要病原体,治疗本地区泌尿生殖道支原体感染可首选阿奇霉素和美满霉素。     

Clinical feature of male non-gonorrhoea urethritis and minocycline treatment of Chlamydia or Ureaplasma-infected urethritis

Thirty-nine male patients with urethritis were studied for gonorrhoea or non-gonorrhoea infections. Only 2 patients were infected with N. gonorrhoeae, the other 37 patients were non-gonorrhoea urethritis (NGU). In 9 of these patients, C. trachomatis was identified and in 6 patients, U. urealyticum was isolated. No chlamydial urethritis was combined with ureaplasma. There was no clinical difference between chlamydia and ureaplasma infection, such as serous urethral discharge or mild pyuria. Minocycline was given orally at the dose of 200 mg daily for 7 to 42 days to these patients. Seven of the 9 patients (78%) with C. trachomatis and 7 of the 6 patients (67%) with U. urealyticum infection showed improvement of subjective and objective symptoms after minocycline. In no case, was an adverse reaction noted. Minocycline was effective in the treatment of both C. trachomatis and U. urealyticum urethral infection.     

Clinical analysis of male urethritis]

We reviewed 497 patients with male urethritis diagnosed between January, 1986 and March, 1989 at the Asama General Hospital. The incidence of gonococcal urethritis (GU) was 47.7%, and that of non-gonococcal urethritis (NGU) 52.3%. There was no difference in the age distribution between GU and NGU. Prostitutes were the most common source of the infection in both GU and NGU. Incubation periods were longer in NGU than in GU, statistically. Urethral discharge was the most common symptom. Purulent urethral discharge was seen more commonly than serous urethral discharge in GU. On the contrary, serous urethral discharge was more common in NGU. Penicillin-resistant gonococcus comprised 29.4% and mixed infection of the C. trachomatis existed 25.6% in GU. C. trachomatis was detected in 71.8% in NGU. In GU, new quinolones and penicillins were administered frequently. The effective rates 1 week after the administration were 80.6% and 83.3%, respectively. In NGU, new quinolones and minocycline were administered frequently. The effective rates were 70.4% and 85.3%, respectively. Ofloxacin (OFLX) showed the highest effective rate to NGU among the four new quinolones. The relapse rate for the two-week administration group was lower than that for the one-week-administration group, but the difference was not statistically significant.     

Assessment of Chlamydia trachomatis, Ureaplasma urealyticum, Ureaplasma parvum, Mycoplasma hominis, and Mycoplasma genitalium in semen and first void urine specimens of asymptomatic male partners of infertile couples

The purpose of this study was threefold: to compare semen and first void urine (FVU) specimens from asymptomatic infertile men for the detection of Chlamydia trachomatis, genital ureaplasma, and genital mycoplasma infections using in-house inhibitor-controlled polymerase chain reaction (PCR)-microtiter plate hybridization assay; to determine the prevalence of those organisms in infertile men in Tunisia; and to study the relationship between these bacteria and male infertility. Paired urine and semen specimens from 104 patients were examined by in-house PCR for the presence of DNA of Chlamydia trachomatis, genital ureaplasmas (Ureaplasma urealyticum and Ureaplasma parvum) and genital mycoplasmas (Mycoplasma hominis and Mycoplasma genitalium). Semen analysis was assessed according to the guidelines of the World Health Organization. Nominal scale variables, the Mann-Whitney test, and the Kruskal-Wallis nonparametric analysis of variance test were used for statistical analysis. There was a very high concordance (>95%) and a very good agreement (kappa > 0.9) between the detection of Chlamydia trachomatis, genital ureaplasmas, and Mycoplasma hominis in semen and corresponding FVU specimens. Our findings also show a high concordance (81.1%) and a good agreement (kappa = 0.79) between the detection of Mycoplasma genitalium in both specimens. C trachomatis, genital mycoplasmas, and genital ureaplasmas were found to be widespread among infertile male patients in Tunisia, as shown by their respective prevalences of 43.3%, 18.3%, and 14.4%. The mean values of seminal volume, sperm concentration, sperm viability, sperm motility, sperm morphology, and leukocyte count were not significantly related either to the detection of C trachomatis DNA or to that of genital ureaplasma or mycoplasma DNA in semen specimens. Using our in-house PCR, both semen and FVU were found to be sensitive diagnostic specimens for the detection of C trachomatis, ureaplasmas, and mycoplasmas. The FVU, a less invasive and self-collected specimen, can serve as a marker for the presence of these organisms in the genital tract and can be used as a reliable way of detecting asymptomatic carriers of infection.     

非淋菌性尿道炎实验诊断研究进展

非淋菌性尿道炎 (NGU)是常见的性传播疾病之一。沙眼衣原体是NGU最常见的病原体 ,NGU的病原体还包括溶脲脲原体、生殖支原体、阴道毛滴虫等。随着分子生物学、免疫学的发展 ,PCR、连接酶链反应 (LCR)等新技术被广泛用于实验室诊断研究中 ,因而有必要建立NGU快速、准确的实验诊断方法并将其标准化。本文就NGU的概念、病因学、临床表现、实验室诊断及治疗方面的研究进展作一概述     

DETECTION OF MYCOPLASMA GENITALIUM IN PATIENTS WITH URETHRITIS

Purpose

We attempted to detect Mycoplasma genitalium in urethral swab specimens by a polymerase chain reaction based assay to determine the prevalence of M. genitalium in patients with urethritis.

Materials and Methods

We examined a total of 171 Japanese men who presented to our hospital from February 1995 through January 1997. Of these men 150 had symptoms and signs compatible with acute urethritis and 21 had no symptoms or signs of urethritis. Urethral swab specimens were used to culture Neisseria gonorrhoeae, to detect Chlamydia trachomatis by an enzyme immunoassay and to detect M. genitalium by a polymerase chain reaction based assay.

Results

Gonococcal urethritis was diagnosed in 74 symptomatic men, and nongonococcal urethritis was diagnosed in 76 symptomatic men. Of the 74 cases of gonococcal urethritis 3 (4.1%) were positive for M. genitalium, and 14 (18.9%) were positive for C. trachomatis. Of the 76 cases of nongonococcal urethritis 10 (13.2%) were positive for M. genitalium, and 42 (55.2%) were positive for C. trachomatis. While only 1 of the 42 cases with chlamydial nongonococcal urethritis (2.4%) was positive for M. genitalium, 9 of the 34 chlamydia negative nongonococcal urethritis cases (26.5%) were positive for the mycoplasma. In contrast, all 21 cases men were negative for N. gonorrhoeae, M. genitalium, and C. trachomatis.

Conclusions

The prevalences of M. genitalium in patients with gonococcal urethritis and nongonococcal urethritis who attended our clinic were 4.1 and 13.2%, respectively. M. genitalium was detected significantly more often in men with nongonococcal urethritis than in asymptomatic men. In addition, its prevalence in men with chlamydia negative nongonococcal urethritis (26.5%) was significantly greater than in those with chlamydia positive nongonococcal urethritis (2.4%). These findings suggest that M. genitalium may be associated with the development of nongonococcal urethritis independent of C. trachomatis.     

男性非淋菌性尿道炎患者支原体对抗菌药物的敏感性

目的:了解支原体在男性非淋菌性尿道炎(NGU)的作用和体外对药物敏感性。方法:对864例疑为NGU的男性患者泌尿生殖道标本进行了支原体型别鉴定,用微量肉汤稀释法对支原体进行9种抗菌药物的敏感性测定。结果:272例(31.4%)支原体培养阳性,其中解脲支原体(Uu)176例,人型支原体(Mh)9例;Uu Mh混合感染87例。97.2%的支原体对9种抗菌药物有不同程度的耐药。Uu Mh混合感染的耐药率明显高于单纯Uu感染。结论:Uu Mh混合感染耐药性升高并发生耐药谱变化。对支原体的定期耐药性监测,对临床用药有重要指导意义。     

Clinical observation of non-gonococcal urethritis

Sixty-one male urethritis cases, 28 gonococcal urethritis and 33 nongonococcal urethritis (NGU), were out-patients at the Department of Urology, Asahi General Hospital, during the 4 months, Oct. 1, 1984-Jan. 31, 1985. Thirteen of the 33 NGU patients (39.4%) were infected with C. trachomatis (CT). The efficacy of Doxycycline and the route of infection was studied in the cases of CT-positive CT-negative-NGU. CT infection from prostitutes was not so frequent as in the other pathogen infection of NGU. The efficacy of Doxycycline (100 mg b.i.d. for 2 weeks) against CT infection was excellent in the disappearance of subjective complaints and that of white blood cells in the urethral discharge in the CT positive-NGU group (13/13), in comparison with CT negative-NGU group (7/18). The efficacy of Doxycycline against CT was also confirmed from the follow-up study by the isolation of CT and by detection of CT antigen from urethral swabs using FITC conjugated monoclonal antibody against CT antigen.     

Cytodiagnosis of Chlamydia trachomatis by the immunoperoxidase technic

The PAP-immunocytochemistry using a monoclonal antibody against Chlamydia trachomatis was applied to male patients with clinically manifest urethritis and their female sex partners. In addition, serum levels of the antibody were determined by means of an ELISA system. Immunoperoxidase reactions were recognized on urethral scrapes in 53 (33%) out of 160 cases, and on endocervical specimens in 13 (59%) out of 22 sex partners of PAP-positive patients. In patients with gonococcal urethritis, an infection of C. trachomatis was revealed immunocytochemically in 11 (31%) out of 36 cases, and in 29 (46%) out of 62 cases with non-gonococcal urethritis. Following medication with 200 mg of minocycline or doxycycline per day, PAP staining became negative in 23 (66%) out of 35 cases. The levels of serum antibody against C. trachomatis were undetectable in 8 (26%) out of 29 PAP-positive cases, but positive in 7 (15%) out of 44 PAP-negative cases.     

Treatment of chlamydial urethritis--studies on clinical effects of ofloxacin

Clinical effects of ofloxacin (OFLX) in the treatment of the patients with chlamydial urethritis was studied. OFLX was administered at a dose of 200 mg, three times daily (600 mg) for 14 days. In all of the 26 patients with chlamydial urethritis, C. trachomatis was eliminated in 7 to 14 days after the start of administration. The subjective clinical symptoms such as pain on urination and abnormal urethral feeling was disappeared in all cases within 7 days after the administration. The objective clinical symptoms, urethral discharge, polymorphonuclear leukocyte (PMNL) in urethral discharge and PMNL in first urine were improved in 94, 68, 91% respectively on 14 days after the administration. Overall clinical efficacy rate of OFLX on 7 days, 14 days and 21 days after the administration in this study was 63, 82, 91% respectively. Whereas subjective symptoms of side effects were noted in 2 patients (7.6%), any additional medical care was needed in none of them. Because of the marked improvement of clinical symptoms and the safety administration, OFLX could be the first regimen to be chosen for the treatment of the patients with chlamydial urethritis.     

泌尿生殖道炎症病人支原体感染现况及耐药性分析

目的 :了解泌尿生殖道炎症病人支原体感染现况及耐药性情况。　方法 :统计 1999～ 2 0 0 3年门诊诊断为非淋菌性尿道炎 (NGU)、慢性前列腺炎及盆腔炎等泌尿生殖道疾病病人 30 5 5例 ,分析其支原体培养及药物敏感试验结果。　结果 :30 5 5例病人共检出支原体感染 992例 ( 32 .5 % ) ,5年间差异无显著性 (P <0 .0 5 )。其中单纯溶脲脲原体 (Uu)感染 70 1例 ( 70 .7% ) ,单纯人型支原体 (Mh)感染 4 4例 ( 4 .4 % ) ,Uu和Mh混合感染 2 4 7例 ( 2 4 .9% ) ,单纯Uu感染远高于混合感染和单纯Mh感染 (P <0 .0 1)。单纯Uu感染计数≥ 10 4cfu/ml占 76 .7% ,而单纯Mh感染者≥10 4cfu仅占 18.2 %。对强力霉素、原始霉素、交沙霉素和四环素敏感性较高 ,分别为 94 .3%、96 .6 %、86 .5 %和97.4 % ,对红霉素和氧氟沙星敏感性仅 5 4 .8%和 2 9.4 %。　结论 :在对病人进行支原体检测时 ,应同时进行Uu和Mh的检测 ,并做支原体药物敏感试验 ,以合理选择抗生素。     

The importance and frequency of mixed infections with Chlamydia trachomatis and mycoplasmas in acute gonococcal urethritis

Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis are frequently involved in gonococcal urethritis. We investigated 143 male White and Black patients with gonococcal urethritis (average age 22,5 years). Of these 29% had coexisting Chlam. trachomatis infection, 34% U. urealyticum infection and 13% Mycoplasma hominis infection. Conventional penicillin therapy did not affect Chlam. trachomatis, U. urealyticum or Mycoplasma hominis, which persisted in the lower urogenital tract, causing a so-called 'post-gonococcal urethritis.' Additional therapy with tetracycline or erythromycin was successful in most cases.     

泌尿生殖道支原体感染及体外药敏试验分析

目的:分析本地区解脲脲原体(Uu)和人型支原体(Mh)的感染状况和耐药性,并对耐药机制进行讨论.指导临床合理用药.方法:对1 612例疑为非淋菌性尿道炎(NGU)患者的泌尿生殖道标本进行支原体检测,并对阳性标本进行抗生素敏感试验.结果:1612例标本中,支原体检出1160例,感染率为72%.其中Uu、Mh、Uu Mh感染率分别为71%、19.7%、9.3%,Uu感染明显高于Mh感染,男性Uu感染率(75.5%)高于女性(68%),女性Mh感染率(22.1%)高于男性(16.0%),总感染率女性(59.6%)高于男性(40.4%),差异有统计学意义(P＜0.05).Uu和Mh对强力霉素、交沙霉素、原始霉素较为敏感.耐药率都在5%以下.Uu和Mh对氟喹诺酮类药物耐药率较高.Mh对红霉素、阿奇霉素、克拉霉素耐药率较高.而Uu对其敏感.结论:NGU患者中支原体是主要病原体之一,鉴于耐药菌株的不断变化,建议在进行支原体检测时进行药敏试验,加强对耐药性的监测,并对其耐药机制进行深入研究,对指导临床治疗具有重要意义.新一代四环素类药物可作为Uu和Mh感染的一线药物.     

Clinical study of male urethritis in Oogaki Municipal Hospital

We studied 181 patients diagnosed with male urethritis at Oogaki Municipal Hospital from April 2002 to March 2004. Twenty-two out of 92 patients diagnosed with gonococcal urethritis (GU) and 52 out of 89 patients diagnosed with non-gonococcal urethritis (NGU) were positive for Chlamidia trichomatis by polymerase chain reaction (PCR). Most patients of male urethritis were in their twenties. Of GU patients, 39 (67%) were infected from commercial sex workers (CSWs). Of NGU patients, 12 (30%) were infected from CSWs, 24 (40%) from girl friends and 4 (10%) from their Twenty-eight (48%) out of GU patients were infected through oral sex. spouse. Eighty-three GU patients were treated with SPCM (2 g, one shot). Fifty-five patients could be evaluated for the efficacy of treatment. Elimination rate of Neisseria gonorrhoeae was 100% and 14 out of 18 patients with persisting urethritis had C. trichomatis. Eighty-two NGU patients were treated with minocycline, tosufloxacin, levofloxacin, gatiflixacin or clarithromycine. Sixty-six patients could be evaluated for the efficacy of treatment. Forty-one patients were diagnosed with non-gonococcal chlamydial urethritis (NGCU) and 25 patients were diagnosed with non-gonococcal, non-chlamydial urethritis (NGNCU). The clinical curative rate of NGCU and NGNCU was 93% (38/41) and 80% (20/25), respectively.     

1186例慢性前列腺炎且不育患者前列腺按摩液中病原体检测及耐药性分析

目的:探讨慢性前列腺炎伴不育患者EPS中分离的细菌菌谱分布及衣原体和支原体感染情况,为临床提供用药依据。方法:对临床采集的慢性前列腺炎且不育患者EPS标本进行培养、鉴定、药物敏感试验,用荧光PCR法检测沙眼衣原体,并对所得结果进行统计学分析。结果:1 186例患者的EPS标本中,病原体总阳性率51.7%,其中革兰阳性球菌364例;革兰阴性杆菌20例;其他菌株5例;支原体157例,其中溶脲脲原体116例、人型支原体41例;沙眼衣原体DNA阳性67例。分离到的葡萄球菌对万古霉素全部敏感;对青霉素类耐药率最高,为76.9%~100%。无乳链球菌对红霉素及克林霉素的耐药率最高,为100%;对β-内酰胺类、氨基糖苷类、复方新诺明、利福平、万古霉素全部敏感。溶脲脲原体对环丙沙星耐药率最高,为59.5%;对交沙霉素、四环素、磷霉素耐药率最低,为1.7%。人型支原体对红霉素的耐药率最高,为100%;对强力霉素、磷霉素全部敏感。结论:慢性前列腺炎伴不育患者EPS中有很大部分可分离到细菌及支原体和衣原体,表明感染是引起男性不育的一个重要因素,分离菌株对不同抗菌药物耐药性有较大差异。     

Case-control study of men with suspected chronic idiopathic prostatitis

We studied prospectively 50 asymptomatic men (24 men from infertile couples and 26 normal volunteers) with no history of genitourinary infection and 34 men referred for symptoms of chronic prostatitis. Both groups were evaluated by urethral and prostatic secretion cultures for Chlamydia trachomatis, 4-glass prostatic localization cultures for facultative aerobic bacteria (Ureaplasma urealyticum, Mycoplasma hominis and selected fungi) and counts of prostatic fluid leukocytes. The men with symptoms of prostatitis had more than 1,000 leukocytes per mm. in prostatic secretions more often than did controls (11 of 27 versus 0 of 44, p less than 0.001). The concentration of Ureaplasma urealyticum in prostatic secretions was 1 log higher in prostatic fluid localization cultures than in first voided urine in 0 of 30 patients versus 13 of 50 controls (p equals 0.0014). Chlamydia trachomatis was not isolated from any patient or control. No other significant differences were found between patients and controls. We did not identify an infectious cause of chronic nonbacterial prostatitis.     

甘肃省张掖市2 356例患者泌尿生殖道衣原体、支原体感染的调查与药敏分析

目的：了解甘肃省张掖市2000-2004年间2356例可疑非淋菌性尿道炎（NGU）患者泌尿生殖道分泌物衣原体、支原体感染及药敏状况。方法：应用衣原体试剂盒（胶体金法）定性检测衣原体抗原、支原体培养及药敏选用支原体药敏试剂盒,并对10种抗生素对支原体的敏感性进行了分析。结果：2356例可疑NGU患者检出衣原体阳性者384例（16．29％）,支原体阳性者324例（13．29％）,混合感染者57例（2．42％）。支原体敏感的药物是多西环素、交沙霉素、米诺环素,耐药的是环丙沙星、氧氟沙星、克林霉素。结论：张掖地区NGU患者的病原体仍然主要是衣原体、支原体,多西环素、交沙霉素、米诺环素可作为支原体感染的首选药物,同时,NGU的病原学检测和药敏试验对其防治尤为重要。